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Failure to close the side branches of the internal mammary artery can result in ischemia due to coronary steal through a patent mammary artery side branch after coronary artery bypass grafting. The authors present the case of a 56-year-old man with recurrent angina after 6 month surgical myocardial revascularization underwent coronary angiography that showed patent left branch of the internal mammary artery. After demonstration of inducible ischemia, effective percutaneous treatment was performed using coil embolization, improving blood flow and clinical symptoms., (© 2024 Wiley Periodicals LLC.)

Background: Graft choices other than left anterior descending artery (LAD)-internal thoracic artery (ITA) anastomosis in coronary artery bypass grafting (CABG) surgery are still controversial. Although 2-dimensional transthoracic echocardiography (2D TTE) is still the most commonly used method, more is needed to diagnose myocardial dysfunction. Ventricular strain values obtained by speckle tracking echocardiography (STE) or tissue Doppler imaging (TDI) methods can much better detect subclinical changes. This study aims to detect early postoperative myocardial function changes compared to single ITA/Bilateral Internal Thoracic Artery (BITA) use by measuring 3-dimensional ejection fraction (3D EF) and ventricular strain values and comparing them according to graft preference., Methods: The study included 35 isolated CABG patients. All patients underwent on-pump CABG via sternotomy. The patients were divided into two groups using single ITA and BITA. Preoperative and postoperative 1st-week 3D EF and ventricular strain values of the patients were calculated using semi-automatic software. The recorded data were compared and evaluated between the two groups., Results: Of The 35 patients participating in the study, 74.3% (n = 26) were male, 25.7% (n = 9) were female, and their average age was 62.7 ± 7.9 years. Preoperative 3D EF values of the patients were 54.4 ± 8.3% and postoperative 49.5 ± 8.2%. The mean preoperative Apical Long Axis Longitudinal Strain (APLAX LS) was calculated as - 16.2 ± 5.0%, 4 Chambers Longitudinal Strain (4CH LS)-16.8 ± 4.6%, 2 Chambers Longitudinal Strain (2CH LS) - 17.0 ± 4.9%, and Global Longitudinal Ventricular Strain (GLVS) - 16.7 ± 4.2%. Postoperative strain values were measured as - 15.1 ± 4.8%, - 14.7 ± 4.9%, - 14.6 ± 5.6% and - 14.8 ± 4.6%, respectively. When the groups were evaluated within themselves, the mean preoperative 3D EF of the patients in the single ITA group was 52.5 ± 8.8%, while the postoperative mean was 47.7 ± 6.0%. In the BITA group, preoperative 3D EF was 56.3 ± 7.5 and postoperative 51.4 ± 9.8. A decrease in strain values was detected in all groups except APLAX planes., Conclusions: In our study, no statistically significant difference was observed in terms of myocardial function changes according to the use of ITA/BITA. However, the decline in postoperative strain values of patients in the BITA group was more remarkable, and it was thought that this may be due to prolonged aortic cross clamp (CC) and cardiopulmonary bypass (CPB) times., (© 2024. The Author(s).)

Background: Studies on the relationship between the preoperative quantitative flow ratio (QFR) and parameters of intraoperative transit time flow measurement (TTFM) are extremely rare. In addition, the predictive value of QFR and TTFM parameters for early internal mammary artery (IMA) failure after coronary artery bypass grafting still needs to be validated., Methods and Results: We retrospectively collected data from 510 patients who underwent in situ IMA grafting to the left anterior descending (LAD) artery at Fuwai Hospital. Spearman correlation coefficients between preoperative QFR of the LAD artery and intraoperative TTFM parameters of the IMA were -0.13 (P=0.004) for mean graft flow (Qm) and 0.14 (P=0.002) for the pulsatility index (PI). QFR and TTFM exhibited similar and good predictive value for early IMA failure (5.7% at 1 year), and they were better than percentage diameter stenosis (area under the curve 0.749 for QFR, 0.733 for Qm, 0.688 for PI, and 0.524 for percentage diameter stenosis). The optimal cut-off value of QFR was 0.765. Both univariate and multivariable regression analyses revealed that QFR >0.765, Qm ≤15 mL/min, and PI >3.0 independently contributed to early IMA failure., Conclusions: There were statistically significant correlations between preoperative QFR of the LAD artery and intraoperative TTFM parameters (Qm, PI) of the IMA. Preoperative QFR and intraoperative Qm and PI exhibited excellent predictive value for early IMA failure.

In coronary artery bypass grafting (CABG) the use of the internal thoracic artery (ITA), is a Class I indication for the left anterior descending (LAD) artery. Atherosclerosis is a systemic disease, and peripheral arterial disease (PAD) is an important complicator of CABG, present in about one-third of the patients with coronary disease. In Leriche Syndrome, ITA can be the source of collateral circulation for arteries below the level of occlusion. Its inadvertent use can lead to serious ischemic complications in the dependent territories.

Background: Suitable autologous conduits may be lacking when performing coronary artery bypass grafting. The aim of this review is to determine the status of nonautologous grafts in coronary artery bypass grafting., Methods: We conducted a literature search on MEDLINE All, Embase Classic, and Embase through Ovid from 1960 to April 2020., Results: Of the 1579 records identified, 21 studies were included in the review. The following grafts were assessed for patency: 109 homologous saphenous veins (patency rates ranged from 66.7% at a median follow-up of 8.5 months to 0% at 6-12 months and 7-18 months, respectively), 29 expanded polytetrafluoroethylene grafts (from 80% at a median follow-up of 5 months to 14.3% at 45 months), 12 human umbilical veins (50% at a median follow-up of 6 months), 50 Bioflow bovine internal mammary arteries (from 15.8% to 0% at a mean follow-up of 9.5 months and 19 months, respectively), 39 Perma-Flow grafts (80% and 76.9% at 1-3 months and 12 months, respectively), 20 No-React bovine internal mammary arteries (57.1% at a median follow-up of 28 months and 23.1% at a mean follow-up of 7 months), 40 autologous venous endothelial cell-seeded expanded polytetrafluoroethylene grafts (94.7% and 81% at a mean follow-up of 27 months and 60 months, respectively), and 12 autologous venous endothelial cell-seeded cryopreserved homologous veins (83.3% at a mean follow-up of 8.5 months)., Conclusions: The goal of an alternative conduit with patency and attributes that match those of autografts remains elusive. Autologous endothelial cell-seeded synthetic grafts have demonstrated promising results but require further investigation., (Copyright © 2021 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: The use of the left internal thoracic artery (LITA) is the gold standard in coronary artery bypass graft surgery (CABG). Multiarterial grafting for CABG is being increasingly emphasized. This study aimed to resolve the utility of the right internal thoracic artery (RITA) for multiple CABG as "free" RITA and described new evidence., Methods: One hundred sixty-three patients received solo CABG with bilateral internal thoracic arteries between 2005 and 2018. The RITA was used as in situ RITA, group A (n = 62), and the composite graft created with saphenous vein graft (SVG), group B (n = 101). The patency rate and graft size of the composite free RITA and SVG were examined by coronary computed tomography angiography., Results: The average number of distal anastomoses per patient was 3.4 ± 1.0 in group A, and 4.2 ± 1.1 in group B (P < .001). The sequential grafting with free RITA was in 86 patients. The patency rate of both LITA and RITA was similar in both groups. In group B, 40 patients received late computed tomography angiography at a mean of 46 months (range, 17 to 175). The late patency rate was 95.1% in LITA and 96.9% in free RITA. The diameter of free RITA increased from 2.06 ± 0.34 mm to 2.37 ± 0.23 mm (P = .036); that of in situ LITA increased from 2.08 ± 0.51 mm to 2.44 ± 0.49 mm (P = .047); and that of composite SVG decreased from 4.1 ± 0.9 mm to 2.6 ± 0.7 mm (P < .001)., Conclusions: Multiple bypass grafting can be sufficiently achieved with LITA and free RITA. The growth potential of free RITA and in situ LITA might play the important role of expected long-term patency., (Copyright © 2021 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Objectives: We compared 10-year graft patency rates and long-term clinical outcomes after off-pump coronary artery bypass grafting using the saphenous vein composite grafts based on the left internal thoracic artery with those using total arterial composite grafts., Methods: A total of 483 patients who underwent off-pump coronary artery bypass grafting using composite grafts based on the left internal thoracic artery were included. The saphenous vein was used as a second (connected to the left internal thoracic artery; n = 63) or a third (connected to the second arterial graft; n = 40) composite graft in 103 patients (SV group); total arterial composite grafting was performed in 380 patients (ART group). A propensity score-matched analysis was used to match the SV group to the ART group (n = 103 patients in each). The median follow-up duration was 128 (97-139) months., Results: There were no differences in operative mortality and postoperative complication rates between the 2 matched groups. Propensity score-matched analyses showed no differences in the overall survival and freedom from cardiac death rates between the 2 groups (P = .369 and P = .206, respectively) up to 12 years after surgery. Freedom rates from reintervention and major adverse cardiac and cerebrovascular events were also similar between the 2 matched groups (P = .695 and P = .758, respectively) up to 12 years after surgery. Generalized mixed-effects models showed that the 2 matched groups demonstrated no differences in overall and composite graft patency rates during 10 years after surgery (P = .568 and P = .702, respectively)., Conclusions: The saphenous vein composite grafts were equivalent to arterial composite grafts in terms of 10-year graft patency and long-term clinical outcomes., (Copyright © 2020 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Fueled by the global surge in aging, atherosclerotic cardiovascular disease reached pandemic dimensions putting affected individuals at enhanced risk of myocardial infarction, stroke, and premature death. Atherosclerosis is a systemic disease driven by a wide spectrum of factors, including cholesterol, pressure, and disturbed flow. Although all arterial beds encounter a similar atherogenic milieu, the development of atheromatous lesions occurs discontinuously across the vascular system. Indeed, the internal mammary artery possesses unique biological properties that confer protection to intimal growth and atherosclerotic plaque formation, thus making it a conduit of choice for coronary artery bypass grafting. Its endothelium abundantly expresses nitric oxide synthase and shows accentuated nitric oxide release, while its vascular smooth muscle cells exhibit reduced tissue factor expression, high tPA (tissue-type plasminogen activator) production and blunted migration and proliferation, which may collectively mitigate intimal thickening and ultimately the evolution of atheromatous plaques. We aim here to provide insights into the anatomy, physiology, cellular, and molecular aspects of the internal mammary artery thereby elucidating its remarkable resistance to atherogenesis. We propose a change in perspective from risk to resilience to decipher mechanisms of atheroresistance and eventually identification of novel therapeutic targets presently not addressed by currently available remedies.

Introduction: Left internal mammary artery (LIMA) grafts should be used in patients undergoing CABG. No other procedure results in patency equivalent to that of the left anterior descending coronary artery (LAD)-LIMA bypass graft. The CHA2DS2-Vasc-HS scoring system can be used to successfully predict CAD severity in stable CAD patients. We aimed to investigate the relationship between LIMA flow and the CHA2DS2-Vasc-HS score., Methods: A total of 684 patients, who underwent CABG surgery, were included in this study. Previous history of bypass surgery, emergency operations, patients with Leriche syndrome and patients with severe obstructive pulmonary and subclavian artery disease were excluded from our study. Patients with a LIMA flow that was suitable for bypass grafting, as determined during the intraoperative evaluation, were included in the low LIMA flow group, and the CHA2DS2-Vasc-HS score was calculated for all patients., Results: Patients in the low LIMA flow group (Group 1) were older. The CHA2DS2-Vasc-HS score (P < 0.001), presence of mild or moderate COPD (P = 0.022), number of severely diseased vessels (P = 0.036), and BMI (P < 0.001) were independent predictors of poor LIMA flow. The cutoff value of the CHA2DS2-VASc-HS score for the prediction of poor LIMA flow was >5.5, with a sensitivity of 92.9% and specificity of 83.4% (AUC: 0.938, 95% Cl: 0.906 - 0.970, P < 0.001)., Conclusion: A preoperative high CHA2DS2-Vasc-HS score can be used to predict low intraoperative LIMA flow. The CHA2DS2-Vasc-HS score is an easy-to-use and reliable estimation method and can be used as an additional preoperative of LIMA flow in patients undergoing CABG due to severe CAD.

Background Several randomized trials have compared the patency of coronary artery bypass conduits. All of the published studies, however, have performed pairwise comparisons and a comprehensive evaluation of the patency rates of all conduits has yet to be published. We set out to investigate the angiographic patency rates of all conduits used in coronary bypass surgery by performing a network meta-analysis of the current available randomized evidence. Methods and Results A systematic literature search was conducted for randomized controlled trials comparing the angiographic patency rate of the conventionally harvested saphenous vein, the no-touch saphenous vein, the radial artery (RA), the right internal thoracic artery, or the gastroepiploic artery. The primary outcome was graft occlusion. A total of 4160 studies were retrieved of which 14 were included with 3651 grafts analyzed. The weighted mean angiographic follow-up was 5.1 years. Compared with the conventionally harvested saphenous vein, both the RA (incidence rate ratio [IRR] 0.54; 95% CI, 0.35-0.82) and the no-touch saphenous vein (IRR 0.55; 95% CI, 0.39-0.78) were associated with lower graft occlusion. The RA ranked as the best conduit (rank score for RA 0.87 versus 0.85 for no-touch saphenous vein, 0.23 for right internal thoracic artery, 0.29 for gastroepiploic artery, and 0.25 for the conventionally harvested saphenous vein). Conclusions Compared with the conventionally harvested saphenous vein, only the RA and no-touch saphenous vein grafts are associated with significantly lower graft occlusion rates. The RA ranks as the best conduit. Registration URL: https://www.crd.york.ac.uk/prospero; Unique identifier: CRD42020164492.

Purpose: The left internal mammary artery (LIMA) is the preferred graft for coronary artery bypass grafting, but the reasoning for LIMA occlusion is unclear. We sought to examine whether the wall shear stress (WSS) values of LIMA grafts during the perioperative period reflected the 1-year patency by using combining computational fluid dynamics (CFD) and coronary computed tomography angiography (CCTA) images., Methods: CCTA was performed in 233 patients with LIMA graft perioperatively and 1 year later from October 2014 to May 2017. LIMA occlusion was detected in six patients at the 1-year follow-up CCTA. Two patients were excluded due to poor imaging quality. The remaining four patients were enrolled as occlusive (OCC) group, and eight patients with patent LIMA were recruited as patent (PAT) group. The WSS values of LIMA during perioperative period were calculated. LIMA graft was artificially divided into three even segments, proximal (pLIMA), middle (mLIMA) and distal (dLIMA) segments. The independent samples t -test and the Student-Newman-Keuls test were used., Results: The WSS values of dLIMA were significantly higher in the PAT group than in the OCC group (4.43 vs. 2.56, p  < 0.05). The WSS values of dLIMA in the PAT group were significantly higher than pLIMA, which was absent in the OCC group., Conclusions: A higher WSS value of the distal segment of LIMA and a higher WSS value of the distal segment compared with the proximal segment of LIMA in the PAT were observed; this tendency might be helpful in predicting the 1-year patency of LIMA., Competing Interests: None declared., (Thieme. All rights reserved.)

Objectives: The aim of this study was to elucidate the remodelling of the internal mammary artery (IMA)-left anterior descending artery anastomosis and compare 2 different anastomosis techniques (end-to-side versus side-to-side) using computational fluid dynamics., Methods: This study included 9 patients. Computed tomography (CT) angiography was performed immediately after coronary artery bypass grafting (CABG) and at 3-6 months later. The computational fluid dynamics models were made using the CT data. The pulsatile 3-dimensional blood flow was achieved with the finite volume method to evaluate the postoperative morphological and haemodynamic changes at the anastomosis in each patient. Flow velocity distribution, wall shear stress (WSS) and its fluctuation oscillatory shear index were measured., Results: No early or mid-term graft occlusion was observed in the study series. In the side-to-side anastomosis, pouch formation at the distal end of IMA caused a vortex flow with low WSS immediately after CABG. However, at 3-6 months after surgery, this pouch disappeared. As a result, the laminar straight flow with uniform WSS distribution was achieved inside the anastomosis. In the end-to-side anastomosis, the anastomosis shape was remodelled, resulting in a laminar flow pattern with uniform WSS distribution. A patchy high oscillatory shear index was detected at the IMA wall on the top of anastomosis in either anastomosis techniques immediately after the surgery, but it disappeared at 3-6 months after surgery., Conclusions: Regardless of the anastomosis technique used, a successful remodelling of the IMA-left anterior descending artery anastomosis shape was achieved a few months after surgery, resulting in a straightforward flow streamline, with uniform WSS distribution and minimal oscillatory shear index., (© The Author(s) 2020. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)

Transit-time flow measurement (TTFM) is frequently used to evaluate intraoperative quality control during coronary artery bypass grafting (CABG) and has the ability to assess graft failure intraoperatively. However, perioperative factors affecting TTFM during CABG remain poorly understood. Patients who underwent CABG at a single institution between July 2016 and May 2018 were prospectively evaluated. TTFM and blood viscosity were measured haemodynamically, while mean flow (mL/min), pulsatility index, and diastolic filling were recorded. Arterial blood gas was analysed immediately after left internal mammary artery to left descending artery anastomosis and before sternal closure. Factors associated with TTFM were assessed using multiple linear regression analysis. We evaluated 57 of the 62 patients who underwent CABG during the study period, including 49 who underwent off-pump and 8 who underwent on-pump surgeries. Blood viscosity was not significantly associated with TTFM (p > 0.05). However, TTFM was significantly associated with body mass index, systolic blood pressure, and cardiac index (p < 0.05 each). In conclusion, maintaining the SBP in the perioperative period and maintaining the CI with inotropic support or fluid resuscitation can be important in improving blood flow of graft vessels after surgery.

Background: The method of coronary-coronary bypass grafting was described in 1987 but has not been widely used, and there are only a few studies that report good short-term and mid-term results as well as some individual cases of long-term follow-up. In our medical institution, we carried out an analysis of the long-term results of coronary-coronary bypass grafting, which are presented in this study., Methods: This was a retrospective single-center study on 95 patients who underwent coronary-coronary bypass grafting as a supplement to the standard coronary bypass grafting procedure. All patients underwent angiographic assessment of the coronary bypass grafts during the long-term follow-up period. The observation period was up to 123 months. Angiographic assessment of 109 coronary-coronary grafts was carried out., Results: Twelve (7.6%) arterial and 11 (19.3%) venous conduits were found to be occluded, and 8 (10.3%) arterial and 10 (31.3%) venous coronary-coronary grafts were occluded during the observation period., Conclusion: Arterial coronary-coronary artery bypass grafting represents an alternative technique that allows complete myocardial revascularization.

Background: Recent coronary surgery practice is to graft arterial conduits to more severely stenosed coronary targets than in the past. We aimed to investigate postoperative arterial graft patency with native coronary stenosis at the time of surgery, using the left internal mammary artery and radial artery (RA) as a composite Y graft (LIMA-RA-Y). In the study timeframe, it was routine clinical practice to graft coronary arteries with >50% stenosis., Methods: Of 464 patients previously reported 1996-1999, 346 who underwent LIMA-RA-Y at the Royal Melbourne Hospital, 76 had postoperative angiograms at the same institution. Each anastomosis was considered separately. For arterial grafts a "string sign" was analysed as being occluded. Predictor of patency was performed with a generalised linear mixed model (GLMM)., Results: Seventy-six (76) patients had postoperative angiograms at 5.8±5.4 years (range 0.23-19.4; interquartile range 1.7-10.0) years postoperative; with age at operation 62.5±10.7 years and 3.4±0.8 grafts per patient, 82% were male. Of 256 anastomoses, 230 were to coronary targets >50% stenosis. Overall patency was 84.0% (214/256). For coronary stenosis >50%, patency was 88% (201/230) and varied by coronary territory left anterior descending (LAD) 94% (87/93), circumflex 90% (71/79) and right coronary artery (RCA) 74% (43/58). Interaction for coronary territory was significant (p=0.022). Higher preoperative coronary stenosis predicted higher patency; with odds ratio for improved patency of 1.83 (95% CI 1.51, 2.22), p<0.001 for each 10% increase in stenosis., Conclusions: Late patency of composite arterial grafts is acceptable when grafted to coronary arteries of greater than 50% stenosis., (Crown Copyright © 2019. Published by Elsevier B.V. All rights reserved.)

Background: Where each patient has all three conduits of internal mammary artery (IMA), saphenous vein graft (SVG) and radial artery (RA), most confounders affecting comparison between conduits can be mitigated. Additionally, since SVG progressively fails over time, restricting patient angiography to the late period only can mitigate against early SVG patency that may have occluded in the late period., Methods: Research protocol driven conventional angiography was performed for patients with at least one of each conduit of IMA, RA and SVG and a minimum of 7 years postoperative. The primary analysis was perfect patency and secondary analysis was overall patency including angiographic evidence of conduit lumen irregularity from conduit atheroma. Multivariable generalized linear mixed model (GLMM) was used. Patency excluded occluded or "string sign" conduits. Perfect patency was present in patent grafts if there was no lumen irregularity., Results: Fifty patients underwent coronary angiography at overall duration postoperative 13.1 ± 2.9, and age 74.3 ± 7.0 years. Of 196 anastomoses, IMA 62, RA 77 and SVG 57. Most IMA were to the left anterior descending territory and most RA and SVG were to the circumflex and right coronary territories. Perfect patency RA 92.2% was not different to IMA 96.8%, P = 0.309; and both were significantly better than SVG 17.5%, P < 0.001. Patency RA 93.5% was also not different to IMA 96.8%, P = 0.169, and both arterial conduits were significantly higher than SVG 82.5%, P = 0.029. Grafting according to coronary territory was not significant for perfect patency, P = 0.997 and patency P = 0.289. Coronary stenosis predicted perfect patency for RA only, P = 0.030 and for patency, RA, P = 0.007, and SVG, P = 0.032. When both arterial conduits were combined, perfect patency, P < 0.001, and patency, P = 0.017, were superior to SVG., Conclusions: All but one patent internal mammary artery or radial artery grafts had perfect patency and had superior perfect patency and overall patency compared to saphenous vein grafts.

Coronary artery disease (CAD) remains one of the most important causes of morbidity and mortality worldwide, and the availability of percutaneous or surgical revascularization procedures significantly improves survival. However, both strategies are daunted by complications which limit long-term effectiveness. In-stent restenosis (ISR) is a major drawback for intracoronary stenting, while graft failure is the limiting factor for coronary artery bypass graft surgery (CABG), especially using veins. Conversely, internal thoracic artery (ITA) is known to maintain long-term patency in CABG. Understanding the biology and pathophysiology of ISR and vein graft failure (VGF) and mechanisms behind ITA resistance to failure is crucial to combat these complications in CAD treatment. This review intends to provide an overview of the biological mechanisms underlying stent and VGF and of the potential therapeutic strategy to prevent these complications. Interestingly, despite being different modalities of revascularization, mechanisms of failure of stent and saphenous vein grafts are very similar from the biological standpoint., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2019. For permissions, please email: journals.permissions@oup.com.)

Background: Internal thoracic artery (ITA) grafts are the most durable conduits available for coronary artery bypass grafting (CABG). However, little is known about long-term angiographic outcomes of ITA grafts used in different configurations and whether sequential or Y grafting compromises patency of the inflow ITA graft., Methods: From January 1972 to August 2016, 60,500 patients underwent primary isolated CABG, of whom 326 received ITA grafts placed in sequential or Y configuration and were studied angiographically (median 4.8 years to first follow-up angiogram). Each sequential or Y segment was studied individually using a mixed-effects longitudinal model with the patient as the random effect., Results: At 15 years, patency of the proximal ITA segment (n = 331) was 99%; of a sequential segment (n = 222), 97%; and of the segment beyond anastomosis of a Y graft (n = 109), 99%. Patency of the Y grafts (n = 109) was 92% at 5 years, 91% at 10 years, and 90% at 15 years. After adjusting for proximal stenosis and graft location, Y grafts were associated with greater occlusion than the inflow segment of ITA grafts (odds ratio; 51, 95% confidence interval, 6.1 to 422; p = 0.003) and of sequential grafts (odds ratio, 12; 95% confidence interval, 1.14 to 120; p = 0.04)., Conclusions: Long-term patency of ITA grafts in sequential or Y configuration is similar qualitatively, but not quantitatively, to the known patency of single ITA-to-left anterior descending grafts. Sequential or Y grafting does not compromise patency of the inflow portion of an ITA graft. Y-graft patency is lower than sequential graft patency but is still better than known patency of saphenous vein grafts., (Copyright © 2019 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

A best evidence topic was constructed according to a structured protocol. The question addressed was whether the configuration of bilateral internal thoracic arteries (BITAs) influences survival, patency or repeat revascularization in patients undergoing coronary artery bypass grafting. Five hundred and seventy-one papers were found using the reported searches, of which 8 represented the best evidence to answer the clinical question. One systematic review, 4 randomized trials and 3 observational studies were selected. The authors, date, journal, study type, population, main outcome measures and results are tabulated. All 4 prospective randomized trials found no significant difference in graft patency or mortality when comparing Y-graft and in situ configurations. Three of the 4 randomized trials found no difference in major adverse cardiovascular and cerebrovascular events or repeat revascularization at follow-up. An exception was Glineur et al. (Bilateral internal thoracic artery configuration for coronary artery bypass surgery: a prospective randomized trial. Circ Cardiovasc Interv 2016;9:7), who found that the Y-configuration resulted in lower rates of major adverse cardiovascular and cerebrovascular events. All 3 observational studies reviewed found no alteration in survival, cardiac events or repeat revascularization between in situ and Y-graft BITA configurations. One systematic review found similar outcomes with respect to mortality, cardiac events and repeat revascularization with in situ and composite BITA. In summary, existing literature demonstrates no difference in clinical outcomes between composite and in situ graft configurations. Furthermore, the configuration of BITA does not affect mortality, graft patency or repeat revascularization.

Homocysteine (Hcy) is an independent risk factor for endothelial dysfunction in cardiovascular diseases. We hypothesized that the eNOS transcription enhancer AVE3085 may protect the endothelial function damaged by Hcy in the human internal mammary artery (IMA). Cumulative concentration-relaxation curves to acetylcholine (-10 to -4.5 log mol/L) or sodium nitroprusside were established in IMA from patients undergoing coronary artery surgery precontracted by U46619 (-8 log mol/L) in the absence/presence of Hcy (100 μmol/L) with/without AVE3085 (30 μmol/L) in vitro in a myograph. RT-qPCR and ELISA were used to quantify the mRNA and protein levels of eNOS. Colorimetric assay method was used to detect the production of nitric oxide (NO). Maximal relaxation was significantly attenuated by Hcy in human IMA. Co-incubation with AVE3085 protected endothelium from the impairment by Hcy and increased the production of NO. Exposure to Hcy for 24 h downregulated eNOS protein expression (P < 0.05) whereas it upregulated the expression of eNOS at mRNA levels (P < 0.05). The presence of AVE3085 in addition to Hcy significantly increased the eNOS protein (P < 0.05) and slightly decreased the mRNA level. The study for the first time revealed that in the human blood vessels (IMA) the clinically-relevant high concentration of Hcy directly causes endothelial dysfunction by downregulating eNOS protein that may be reversed by AVE3085. These findings not only provide new direction for protecting endothelium during coronary artery bypass grafting and improving long-term patency of the grafts, but also provide evidence to the use of eNOS enhancer in the patients with endothelial dysfunction in various pathological conditions., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Using the atomic force microscopy- (AFM-) PeakForce quantitative nanomechanical mapping (QNM) technique, we have previously shown that the adventitia of the human internal mammary artery (IMA), tested under dehydrated conditions, is altered in patients with a high degree of arterial stiffening. In this study, we explored the nanoscale elastic modulus of the tunica media of the IMA in hydrated and dehydrated conditions from the patients with low and high arterial stiffening, as assessed in vivo by carotid-femoral pulse wave velocity (PWV). In both hydrated and dehydrated conditions, the medial layer was significantly stiffer in the high PWV group. The elastic modulus of the hydrated and dehydrated tunica media was significantly correlated with PWV. In the hydrated condition, the expression activity of certain small leucine-rich repeat proteoglycans (SLRPs), which are associated with arterial stiffening, were found to be negatively correlated to the medial elastic modulus. We also compared the data with our previous work on the IMA adventitia. We found that the hydrated media and dehydrated adventitia are both suitable for reflecting the development of arterial stiffening and SLRP expression. This comprehensive study of the nanomechanical properties integrated with the proteomic analysis in the IMAs demonstrates the possibility of linking structural properties and function in small biological samples with novel AFM methods. The IMA is a suitable target for predicting arterial stiffening.

Objective: The aim of the present study was to identify morphological and pathophysiological factors associated with long-term patency of grafts used in coronary artery bypass grafting (CABG)., Methods: A total of 127 patients who underwent CABG between 2000 and 2006 and presented for computed tomography evaluation of graft patency at 139.78±36.64 months post-CABG were analyzed. Patients received 340 grafts (2.68 grafts/patient), 399 distal anastomoses (3.14 anastomoses/ patient), 220 (55.14%) performed using arterial grafts, and 179 (44.86%) using saphenous vein grafts (SVGs)., Results: Graft patency varied according to vessel type and coronary territory. Overall graft patency was 90.16% for the left internal thoracic artery (LITA), 75.55% for the right internal thoracic artery (RITA), 79.25% for the radial artery (RA), and 74.3% for the SVG. The maximum patency rate was obtained with the RA (80.65%) for the right coronary territory, RITA (92.86%) for the anterolateral territory, and SVG (82.54%) for the circumflex territory. The LITA-left anterior descending artery graft occluded in 13 (7.93%) cases, 7 due to competitive flow. The influence of graft length on patency rates after indexing to height was not significant. The target vessel degree of stenosis influenced arterial graft patency rates with an occlusion odds ratio (OR) of 3.02 when anastomosed to target vessels with <90% stenosis. Target vessel caliber also influenced patency rates with occlusion ORs of 2.63 for SVGs and 2.31 for arterial grafts when anastomosed to ≤1.5 mm target vessels., Conclusion: Morphological parameters, such as graft type, target territory, target vessel caliber, and degree of stenosis, are important factors conditioning long-term graft patency.

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether the anterolateral or the inferior wall served as a better location for the 2nd arterial graft in a 3-system coronary artery bypass grafting procedure. In total, more than 1800 papers were found, of which 6 represented the best evidence to answer the clinical question. All papers demonstrated equivalent early postoperative mortality and morbidity. The 3 largest studies comparing bilateral internal thoracic arteries showed no difference in perioperative mortality and morbidity regardless of whether the 2nd internal thoracic artery was used to graft the left or right system. One of these studies, however, showed significant survival benefit for the left-sided group at 8 years, whereas another study showed a reduced patency of right internal thoracic arteries when grafted to the right coronary artery and when used in situ. One study compared radial grafts to the right- and left-sided targets and showed no difference in long-term patency. Another study also reported on the angiographic patency of right internal thoracic arteries. The authors noted a non-significant increase in graft failure when non-left anterior descending arteries were grafted but no difference between circumflex or posterior descending arteries. All studies demonstrated similar or better mid- and long-term outcomes and patency rates when using the 2nd arterial graft to revascularize left-sided targets when compared with the right. However, all outcomes were similar when comparing non-left anterior descending left-sided targets with non-right coronary artery right-sided targets. Therefore, the right coronary artery itself should probably be avoided as the 2nd arterial target.

Objectives: The in situ internal thoracic artery (ITA) is recognized as the best conduit for coronary artery bypass surgery. The ITA-if it is used as an in situ graft-has a much higher late patency rate than any other arterial graft, including a free ITA graft. We sought to determine if the use of the ITA as an in situ/free graft and its storage in preservation solutions, have an effect on endothelial function., Methods: The ITA was harvested as either a free or in situ graft in a porcine model. Free grafts were stored in different preservation solutions (saline, Custodiol and Tiprotec [both Köhler Chemie GmbH, Bensheim, Germany]). The ITA was anastomosed off pump to the left anterior descending artery (as in situ/free graft). Freshly harvested ITA served as a control. After 2 hours of reperfusion, the implanted grafts were harvested. The assessment of endothelial function, histopathological analysis, and gene expression were performed., Results: Endothelial function and integrity were severely impaired after reperfusion in the free ITA groups, however, it was partially preserved in the Tiprotec group. Reperfusion injury resulted in increased nitro-oxidative stress, DNA breakage, vascular cell adhesion protein 1, intercellular adhesion molecule-1, and caspase-3 scores, and a decreased endothelial nitric oxide synthase score in the free ITA groups. The in situ ITA graft showed no signs of injury. mRNA levels were significantly altered among the groups., Conclusions: An early, severe endothelial dysfunction of the stored, free ITA as described, could be completely prevented by the use of an in situ ITA graft. Tiprotec might be a feasible option for storage of free arterial grafts during coronary artery bypass grafting., (Copyright © 2018 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Background: The left internal thoracic artery (LITA) is the most commonly used arterial bypass conduit in coronary artery bypass graft (CABG) patients and inadequate LITA flow can result in an increase in morbidity and mortality. In this study, we evaluated the effect of excision of the distal spasmodic segment of the LITA on the free flow in CABG patients., Methods: This study consisted of 47 patients who underwent elective CABG performed with or without other cardiac surgery, between July 2015 and December 2015. Excised LITA length was shorter than 15mm in group 1, between 15mm and 30mm in group 2 and longer than 30mm in group 3. Left ITA free flow was measured for 60seconds into a container before and after the distal LITA excision. The inter-measurement differences were calculated for the three groups. Thereafter, the comparison was performed in terms of free flow difference amongst the three groups., Results: The mean difference of LITA free flow was 27.6±22.7ml/minute in group 1, 35.4±26.7ml/minute in group 2, and 52.6±26.1ml/minute in group 3. There were significant differences in terms of free flow difference between the groups (p=0.008). Also, differences were statistically significant in group 1 versus group 3 (p=0.003) and group 2 versus group 3 (p=0.038) in the intergroup comparisons., Conclusions: The distal part of the LITA has more spasmodic potential than other segments. This spasm may result in low flow of LITA grafts. Therefore, an as long as possible excision of the distal LITA segment may be required to avoid the spasmodic effect., (Copyright © 2017 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.)

Nitroglycerin is commonly used as an antispasmodic for treating spasm of coronary artery bypass grafts. This study investigated whether the presence of renal failure affects reactivity to nitroglycerin in internal thoracic arteries obtained from patients undergoing coronary bypass surgery. The patients were divided into three groups according to estimated glomerular filtration rate (eGFR, mL/min/1.73 m 2 ): without renal failure (60 ≤ eGFR, n = 13), with moderate renal failure (30 ≤ eGFR < 60, n = 10), and with severe renal failure (eGFR < 30, n = 10). Organ chamber technique was used to evaluate concentration-related responses of isolated internal thoracic arteries to vasodilators. Nitroglycerin induced a concentration-dependent relaxation, which was significantly augmented in patients with severe but not moderate renal failure than in those without renal failure. In addition, there was a negative correlation between eGFR and the relaxant efficacy of nitroglycerin (P = 0.016). On the other hand, relaxant responses to BAY 60-2770 (which enhances cGMP generation as with nitroglycerin) were similar among three grades of renal function. An inverse relationship of eGFR to the relaxant efficacy of BAY 60-2770 was not observed, either (P = 0.314). These findings suggest that severe renal failure specifically potentiates nitroglycerin-induced relaxation in internal thoracic artery grafts.

Background: The long-term benefits of a third arterial conduit to the right circulation in triple-vessel disease remain debatable. This retrospective, single-center, propensity-matched study investigates the impact of a third arterial conduit to the right circulation on early and intermediate survival after coronary artery bypass grafting., Methods: Data were retrospectively collected from 2004 to 2014 for all surgical revascularizations for triple-vessel disease with at least 2 arterial conduits to the left circulation and a third arterial or venous conduit to the right circulation. A total of 167 pairs were propensity matched to arterial versus venous third conduit to right circulation. Hazard functions were obtained with Cox multivariate regression and Kaplan-Meier survival curves were compared between the matched cohorts., Results: Extracardiac arteriopathy, logistic euroSCORE, and left main stem disease were significant predictors of adverse survival. A third arterial conduit to the right circulation was not a significant predictor of improved survival in multivariate analysis (HR, 0.72; 95% CI, 0.34-1.55; P = .411). 30-day mortality was 0.6% in both groups. There was no significant difference in early or intermediate survival in the propensity-matched groups (venous vs arterial, 99.2% vs 99.2%; P = 1.000 at 1 year; 85.2% vs 88.8%; P = .248 at 5 years and 69.2% vs 88.8%; P = .297 at 7 years) CONCLUSIONS: The use of a third arterial versus a venous conduit to the right circulation does not improve early or intermediate survival up to 7 years in triple-vessel coronary artery disease in this study. Longer follow-up and larger cohorts may be needed for differences to emerge., (Copyright © 2017 The American Association for Thoracic Surgery. All rights reserved.)

Background: Endothelial shear stress (ESS) has been suggested as a factor affecting atherosclerosis and remodeling of native vessels and bypass conduits. We compared ESS levels of internal thoracic artery (ITA) and saphenous vein (SV) composite grafts intraoperatively and 1 year after coronary artery bypass grafting (CABG)., Methods: Intraoperative ESS was calculated by measuring flow volumes and diameters of proximal and distal ITAs and SV conduits in 23 patients who received SV Y-composite grafts based on the in situ left ITA. Early (1.2 ± 0.5 days) and 1-year (12.9 ± 1.1 months) postoperative angiograms were performed in 23 and 15 patients, respectively. An intragraft Doppler-guidewire study for ESS measurement was performed in 6 patients during 1-year angiography., Results: Intraoperative diameters of proximal and distal ITAs and SV conduits were 2.0 ± 0.2 mm, 1.8 ± 0.3 mm, and 3.2 ± 0.4 mm, respectively. ESS levels were significantly different between them (41.0 ± 21.0, 28.4 ± 25.2, and 4.3 ± 3.0 dyne/cm 2 , respectively). Proximal and distal ITA diameters increased significantly on early angiograms and remained unchanged, but SV diameter increased to 3.7 mm (95% confidence interval, 3.5 to 4.0 mm; p < 0.001) on the early angiogram and decreased to 2.9 mm (95% confidence interval, 2.7 to 3.2 mm; p < 0.001) at 1 year. Significant correlations were found between the initial ESS and proportional changes in conduit diameters during postoperative year 1. SV ESS increased in all 6 patients at 1 year, with no significant differences in ESS levels between the 3 conduits (29.9 ± 7.9, 28.8 ± 7.9, and 21.6 ± 16.3 dyne/cm 2 , respectively)., Conclusions: Initial ESS appears to be associated with proportional changes in conduit diameters in the first year after CABG. ESS values of SV composite grafts were similar to left ITA conduits 1 year after CABG., (Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

This study aimed to evaluate the feasibility and the mid-term efficacy of an in situ skeletonized right internal mammary artery (IMA) bypass grafting to a left anterior descending artery (LAD), and to determine risk factors for IMA graft failure in a single-center study.From January 2012 to December 2015, 189 patients (173 males, 50.6 ± 6.0 years old) undergoing first isolated coronary artery bypass grafting surgery with the in situ skeletonized right IMA grafting to the LAD were included in this study. Baseline characteristics, peroperative data, and follow-up outcomes were investigated and analyzed.The length of the in situ skeletonized right IMA grafts was 18.6 ± 1.2 cm (17.0-22.0 cm). Intraoperative graft flow of the in situ skeletonized right IMA grafting to LAD was 42 ± 9 mL/minute (18-72 mL/minute) associated with measured pulsatility index of 0.8-4.3. In-hospital mortality was 0.5%. Postoperative morbidity included acute myocardial infarction (0.5%), stroke (0.5%), and deep sternal wound infections (1.1%). The mid-term survival was 97.2% and the incidence of repeat revascularization was 0.6%. The patency rate of the in situ skeletonized right IMA grafting to the LAD was 97.1% by computed tomography angiography examination during the follow-up period of 23.2 ± 9.7 months. Additionally, logistic regression analysis showed that intraoperative graft flow had an independent influence on the risk of the mid-term right IMA graft failure.The strategy of the in situ skeletonized right IMA grafting to the LAD is feasible and effective. Intraoperative graft flow was an independent risk factor for the mid-term right IMA graft failure.

Background and Aims: Obesity is a risk factor for endothelial dysfunction and atherosclerosis. However, perivascular adipose tissue can release adipokines and other unknown adipose-derived relaxing factors. Therefore, we investigated the impact of obesity on vascular function and expression of genes in perivascular adipose tissue from internal mammary arteries of patients with coronary artery disease undergoing coronary artery bypass grafting., Methods: The vessel function was compared between groups of patients with a body-mass index (BMI) between 25 and 30 kg/m 2 . The groups did not differ in age, gender (males), and ejection fraction. Vascular segments of internal mammary arteries were examined in a Mulvany myograph. Following preconstriction with noradrenaline, dose-response curves were assessed for relaxation with acetylcholine and sodium nitroprusside., Results: Maximum contraction in response to potassium and noradrenaline was increased in obese patients with a BMI >30 kg/m 2 . EC50 of endothelium-dependent relaxation was impaired in patients with a BMI above 25, but below 30 kg/m 2 . Sodium nitroprusside-mediated maximal relaxation was not different between study groups. Integrin alpha X chain (ITGAX/CD11c) and macrophage mannose receptor (MRC1/CD206) expression was reduced in perivascular adipose tissue of patients with a BMI above 30 kg/m 2 , while adiponectin (ADPQ) expression was increased in the same tissue., Conclusion: Our data suggest a partially reduced endothelial function in internal mammary arteries of adipose patients with a BMI between 25 and 30 kg/m 2 undergoing coronary artery bypass grafting surgery. Increased adiponectin expression in perivascular tissue might contribute to maintenance of endothelial function in obese patients with a BMI above 30 kg/m 2 ., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Objectives: This study aimed to examine the effect of off-pump coronary artery bypass grafting (CABG) in patients who underwent revascularization with bilateral internal thoracic arteries (ITAs)., Methods: Between January 2000 and December 2014, 499 patients underwent isolated CABG with bilateral ITAs for complete revascularization of the left coronary system at our institution. On-pump CABG was performed in 137 patients, and off-pump CABG was performed in 362 patients. We retrospectively compared the clinical outcomes and patency of the ITAs., Results: The off-pump group showed less respiratory failure and required a shorter postoperative stay than the on-pump group. The survival probability, freedom from cardiac events and early graft patency were similar in both groups. Five-year patency of the ITA anastomosed to the left anterior descending artery was significantly greater in the on-pump group than in the off-pump group (98.8% vs 91.2%, P = 0.010). The incidence of string change in the off-pump group was higher than that in the on-pump group (P = 0.017). There was no significant difference between the groups in the 5-year patency of the ITA anastomosed to the left circumflex artery (on-pump group: 93.8%, off-pump group: 91.8%; P = 0.46)., Conclusions: The early graft patency and the late patency of the ITA anastomosed to the left circumflex artery between the groups were similar, implying an equivalent quality of anastomoses. However, the patency of the ITA anastomosed to the left anterior descending artery in the off-pump group showed late deterioration, mainly because of string sign development., (© The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)

Background: The aim of this prospective study was to compare the effect of application of nitroglycerin and verapamil solution (GV) by organ bath technique with other methods of applications and solutions on the free blood flow of LITA. The technique was not described for in situ graft before., Method: The patients were randomly assigned to four groups: group I (n&#95;32, GV solution by organ bath technique), group II (n&#95;30, papaverine solution by organ bath technique), group III (n&#95;29, topical GV solution) or group IV (n&#95;29, topical papaverine solution). In each patient, pedicled LITA was harvested; thereafter applied with the randomized different methods and solutions. The free flow from the distal end of the divided LITA was measured for 15s under controlled hemodynamic conditions after harvesting (Flow 1). The flow of LITA was measured again just prior to anastomosing the conduit (Flow 2)., Result: The mean blood flow in LITA was 56.2±5.0ml/min before application of solutions. After application, the mean blood flow in group I:102.3±7.0ml/min, in group II: 92.7±3.4ml/min, and in group III: 88.6±2.2ml/min and in group IV: 81.4±2.1. Proportional increases in blood flow observed in group I (82.6%)>group II (65.1%)>group III (57.6)>group IV (44.8%) (p<0.05)., Conclusions: GV solution by organ bath technique is effective and superior in comparison to use of papaverine using organ bath technique or topical spray of GV or papaverine solution., (Copyright © 2017 Cardiological Society of India. All rights reserved.)

There is higher long-term failure of the saphenous vein graft (SVG) compared with the left internal mammary artery (LIMA) graft, which is affected by the hemodynamic environment. A comprehensive analysis of postoperative structure-function changes is important to study the atherogenesis in the SVG A comparison of morphometric and hemodynamic parameters was carried out between LIMA grafts and SVGs and between different time points postoperatively. Various parameters were obtained from the image reconstruction and flow simulation in patients, who underwent CT exams for ~1 year, 5 and 10 years after revascularization. Morphometric data showed a decrease in lumen size in the entire SVG and anastomosis of different patients in a sequence of ~1 year, 5 and 10 years postoperatively despite negligible changes of LIMA size. Computational results indicated the fourfold increased surface area ratio (SAR) of low time-averaged wall shear stress (TAWSS) in the SVG and anastomosis at postoperative 10 years than that at postoperative ~1 year. The SAR of high TAWSS gradient (TAWSSG) at the distal anastomosis between SVG and coronary arteries was significantly higher (14 ± 9% vs. 6 ± 8%) than that in the LIMA group at postoperative ~1 year. There were strong correlations between morphometric and hemodynamic parameters in the SVG and distal anastomosis at various time points postoperatively, which showed deterioration relevant to persistent diffuse diseases at postoperative ~10 years., (© 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.)

The procedure of coronary artery bypass grafting continues to be the "gold standard" for patients with multivessel coronary artery disease and left main stenosis due to favourable long-term and consistent outcomes despite the advent of new generations of stents. But the targeted better long-term outcome of surgical revascularization over percutaneous interventions depends on several variables and aspects; one of them is the choice of conduits used to bypass the stenosed arteries. Coronary artery bypass surgery has been studied and debated for decades and the same applies to the selection of grafts. Current data provide significant benefits for patients who receive full arterial revascularization using both internal thoracic arteries and, if applicable, the radial artery. Unfortunately, the use of multiple arterial grafts is still not performed widely despite the evidence of superiority over multiple saphenous vein grafts that are still the most used grafts in cardiovascular procedures. In this review article, we present current trends and evidences for graft selection and give an overview of controversial data regarding the comparison of the radial artery and saphenous vein. Additionally, few words are spelt on alternative conduits.

Background: Nearly 50% of patients undergoing coronary artery bypass grafting have diabetes. However, little is known about the influence of diabetes on long-term patency of bypass grafts. Because patients with diabetes have more severe coronary artery stenosis, we hypothesized that graft patency is worse in patients with than without diabetes., Objectives: This study sought to examine the influence of diabetes on long-term patency of bypass grafts., Methods: From 1972 to 2011, 57,961 patients underwent primary isolated coronary artery bypass grafting. Of these, 1,372 pharmacologically treated patients with diabetes and 10,147 patients without diabetes had 15,887 postoperative angiograms; stenosis was quantified for 7,903 internal thoracic artery (ITA) grafts and 20,066 saphenous vein grafts. Status of graft patency across time was analyzed by longitudinal nonlinear mixed-effects modeling., Results: ITA graft patency was stable over time and similar in patients with and without diabetes: at 1, 5, 10, and 20 years, 97%, 97%, 96%, and 96% in patients with diabetes, and 96%, 96%, 95%, and 93% in patients without diabetes, respectively (early p = 0.20; late p = 0.30). In contrast, saphenous vein graft patency declined over time and similarly in patients with and without diabetes: at 1, 5, 10, and 20 years, 78%, 70%, 57%, and 42% in patients with diabetes, and 82%, 72%, 58%, and 41% in patients without diabetes, respectively (early p < 0.002; late p = 0.60). After adjusting for patient characteristics, diabetes was associated with higher early patency of ITA grafts (odds ratio: 0.63; 95% confidence limits: 0.43 to 0.91; p = 0.013), but late patency of ITA grafts was similar in patients with and without diabetes (p = 0.80). Early and late patency of saphenous vein grafts were similar in patients with and without diabetes (early p = 0.90; late p = 0.80)., Conclusions: Contrary to our hypothesis, diabetes did not influence long-term patency of bypass grafts. Use of ITA grafts should be maximized in patients undergoing coronary artery bypass grafting because they have excellent patency in patients with and without diabetes even after 20 years., (Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This meta-analysis aims to assess the graft patency quantitatively and statistically., Methods: Eleven observational studies were identified by systematic literature search, incorporating 3311 patients undergoing coronary endarterectomy (CE) + coronary artery bypass graft (CABG) and 3990 undergoing isolated CABG, which were analysed using random-effects modelling. Heterogeneity, quality of scoring and risk of bias were assessed and reangiographic outcomes were documented., Results: Adjunctive CE decreased graft patency [odds ratios = 0.43, 95% confidence interval [0.29-0.63], z  = 4.33, P  < 0.0001] with moderate heterogeneity, while the baseline demographics differed considerably., Conclusions: Whether CE remains a viable option to CABG requires novel studies collecting corresponding data from bench to bedside. To achieve satisfactory efficacy, surgeons should carefully weigh possible benefits and adverse effects of CE and prepare the surgical strategy adequately., (© The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)

Background: Spasm of arterial grafts is still a clinical problem in coronary artery bypass surgery. The present study was designed to examine the effect of particulate guanylyl cyclase activator (carperitide) as an antispastic agent in internal thoracic artery and gastroepiploic artery grafts., Methods: Isolated arterial grafts taken during surgery were studied in organ bath in three ways: the relaxing effect of carperitide on vasoconstrictor-induced precontraction; the inhibitory effect of pretreatment with carperitide on subsequent vasoconstrictor-induced contraction; and the effect of carperitide and nitroglycerin on increase of intracellular cyclic guanosine monophosphate levels., Results: Carperitide produced a concentration-related, endothelium-independent relaxation contracted with potassium chloride, phenylephrine, prostaglandin F 2α , or endothelin-1. Carperitide showed significantly higher potency and efficacy than nitroglycerin and nifedipine. Pretreatment with carperitide significantly attenuated the subsequent vasoconstrictor-induced contraction. Carperitide produced more cyclic guanosine monophosphate than nitroglycerin., Conclusions: Carperitide has a potent inhibitory effect on the vasoconstriction mediated by different vasoconstrictors in human internal thoracic artery and gastroepiploic artery grafts. The use of carperitide in patients during and after coronary artery bypass surgery is favored for the prevention and reversal of graft spasm., (Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Objective: The hemolytic product free-hemoglobin (fHb) reduces nitric oxide (NO) bioavailability. The present study aims to establish whether administration of different blood transfusions result in increased circulating fHb levels and NO consumption with effects on arterial NO-dependent blood flow in patients undergoing CABG surgery., Methods: Ninety-five consecutive patients undergoing elective CABG surgery were prospectively divided in four groups based on blood transfusion requirements during surgery: stored blood cells (SBC, n. 21), intraoperative autologous salvaged blood (ASB, n. 25), SBC and ASB (n.22), no transfusion (control, n. 27). Blood samples were collected before and after intervention to analyse plasma levels of fHb and NO consumption. Endothelium-dependent relaxation was assessed in left internal mammary artery (LIMA) rings harvested before chest closure. Peripheral artery tonometry was assessed after intervention., Results: Transfusions with SBC increased plasma fHb (p<0.05). Transfusions of ASB resulted in higher plasma fHb compared to SBC (p<0.01). fHb concentrations directly correlated with NO consumption (r=0.65, p<0.001). Maximal endothelium-dependent relaxation in LIMA was significantly attenuated in SBC and ASB patients compared to control (15.2±3.1% vs 21.1±2.5% vs 43±5.0% respectively; p<0.01). Significant correlations were identified between the aortic pressure wave velocity, plasma fHb concentration and NO consumption (p<0.01)., Conclusions: Intraoperative blood transfusions and particularly autologous salvaged blood impair endothelium-dependent relaxation through NO scavenging by fHb. These findings obtained in vitro and in vivo provide new insights into the adverse relation between blood transfusions and patient outcome., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Cyclooxygenase-2 (COX-2) induction in human internal mammary arteries (IMA) under inflammatory conditions has been associated with attenuated norepinephrine (NE)-induced vasoconstriction. This effect was associated with increased prostaglandin (PG) E 2 and prostacyclin (PGI 2 ) releases. The present study was designed to assess the role of these PG and their receptors (EP and IP, respectively) on the vascular reactivity during acute inflammation. Isolated IMA were cultured in the absence (Control conditions) or presence (Inflammatory conditions) of both interleukin-1 beta (IL-1β) and lipopolysaccharide (LPS). The vasorelaxation and the increased content of cyclic adenosine monophosphate (cAMP) induced by iloprost, a PGI 2 analogue, were significantly reduced under inflammatory conditions and restored in preparations cultured with the IP antagonist (CAY10441). Decreased cAMP levels under inflammatory conditions are due to at least increased phosphodiesterase (PDE) 4B expression. On the other hand, PGE 2 , thromboxane analogues and EP agonists-induced vasoconstrictions were not affected under inflammatory conditions. No vasorelaxation was observed with PGD 2 , PGE 2 or the EP2/4 agonists in pre-contracted IMA. Finally, using RT-qPCR and immunohistochemistry, the COX-2, IP receptor and PGI 2 synthase (PGIS) were detected. A significant increase of COX-2 and moderate increase of IP mRNA expression was observed under inflammatory conditions, whereas PGIS mRNA level was not affected. This study demonstrates that PGI 2 /IP receptor signalling and PGI 2 -induced relaxation are impaired in human IMA during acute inflammation, whereas the responses induced by other prostanoids are not affected. These results could explain some of the mechanisms of vascular dysfunction reported in inflammatory conditions., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: The objective of this study is to test the effect of permanent right internal mammary artery device closure on coronary collateral function and myocardial ischemia., Methods and Results: This was a prospective, open-label clinical trial in 50 patients with coronary artery disease. The primary study end point was coronary collateral flow index as obtained during a 1-minute proximal right coronary artery (RCA) and left coronary artery balloon occlusion at baseline before and at follow-up examination 6 weeks after distal right internal mammary artery device closure. Collateral flow index is the ratio between simultaneously recorded mean coronary occlusive pressure divided by mean aortic pressure, both subtracted by central venous pressure. Secondary study end points were fractional flow reserve during vessel patency, the quantitative intracoronary ECG ST-segment elevation, and angina pectoris during the same 1-minute coronary occlusion. Collateral flow index in the untreated RCA and left coronary artery changed from 0.071±0.082 at baseline to 0.132±0.117 ( P <0.0001) at follow-up examination and from 0.106±0.092 to 0.081±0.079 ( P =0.29), respectively. RCA fractional flow reserve increased significantly ( P =0.0029) from baseline to follow-up examination, despite deferral of coronary intervention in all patients. There was a decrease in intracoronary ECG ST-elevation during RCA occlusion from baseline to follow-up examination ( P =0.0015); it did not change in the left coronary artery. Angina pectoris during RCA occlusion tended to occur in fewer patients at follow-up versus baseline examination ( P =0.06)., Conclusions: Permanent right internal mammary artery device closure seems to augment extracardiac ipsilateral coronary supply to the effect of reducing ischemia in the dependent myocardial region., Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02475408., (© 2017 The Authors.)

Background: Harvesting the internal thoracic artery (ITA) with semiskeletonization is an alternative technique between conventional wide pedicle and skeletonization. It is almost as simple as pedicle harvesting; however, it is supposed to provide the advantage of graft flow and length. Since the heart is unique being the only organ which is perfused during diastole, for comparing the intraoperative graft flow characteristics of semiskeletonization and pedicle technique, we used diastolic filling (DF) using transit-time flow measurement as a primary result. The objective of this study is to compare if semiskeletonized ITA has a greater effect on the intraoperative DF of graft flow versus conventional pedicled ITA in coronary artery bypass., Methods: Between July 2015 and May 2016, a prospective evaluation of 60 consecutive patients undergoing coronary artery bypass grafting for left anterior descending artery revascularization were randomized to having semiskeletonized (n = 30) or conventional pedicled (n = 30) ITA graft harvested by the same surgeon. Intraoperative transit-time flows were obtained. The DF of the ITA graft at the end of operation was evaluated in two groups., Results: The intraoperative DF was significantly greater in the semiskeletonized grafts than in the pedicled grafts (70.50 ± 14.15 versus 57.6 ± 19.39%; p = 0.005). No statistical difference was observed comparing quantitative pulsatile flow and pulsatile index at the end of the operation in the two groups. However, the free flow of the conduit during the cardiopulmonary bypass before the anastomosis performed was greater in semiskeletonized group than in pedicled group (94 ± 48.37 versus 56.35 ± 34.90 ml/min; p = 0.003). The total operative time was comparable between two groups (p = 0.092)., Conclusions: Semiskeletonized ITA resulted in superior DF of left anterior descending bypass graft flow as compared with pedicled ITA. It is also provide a greater free flow and length of the graft without the long-delayed operative time., Trial Registration: Trial registration number (Study ID): TCTR20160913002 Date of registration: September 10, 2016.

Endothelial dysfunction and inflammation are key mechanisms of vascular disease. We hypothesised that heterogeneity of monocyte subpopulations may be related to the development of vascular dysfunction in coronary artery disease (CAD). Therefore, we examined the relationships between monocyte subsets (CD14 ++ CD16 - "classical - Mon1", CD14 ++ CD16 + "intermediate - Mon2" and CD14 + CD16 ++ "nonclassical - Mon3"), endothelial function and risk factor profiles in 130 patients with CAD undergoing coronary artery bypass grafting. This allowed for direct nitric oxide (NO) bioavailability assessment using isometric tension studies ex vivo (acetylcholine; ACh- and sodium-nitropruside; SNP-dependent) in segments of internal mammary arteries. The expression of CD14 and CD16 antigens and activation markers were determined in peripheral blood mononuclear cells using flow cytometry. Patients with high CD14 + CD16 ++ "nonclassical" and low CD14 ++ CD16 - "classical" monocytes presented impaired endothelial function. High frequency of CD14 + CD16 ++ "nonclassical" monocytes was associated with increased vascular superoxide production. Furthermore, endothelial dysfunction was associated with higher expression of activation marker CD11c selectively on CD14 + CD16 ++ monocytes. Nonclassical and classical monocyte frequencies remained independent predictors of endothelial dysfunction when major risk factors for atherosclerosis were taken into account (β=0.18 p=0.04 and β=-0.19 p=0.03, respectively). In summary, our data indicate that CD14 + CD16 ++ "nonclassical" monocytes are associated with more advanced vascular dysfunction measured as NO- bioavailability and vascular reactive oxygen species production.

Transit-time flow measurement (TTFM) is a reliable method to check the graft function intraoperatively in coronary surgery. The given parameters are: Mean Graft Flow (MGF); Pulsatility Index (PI) and Insufficiency Ratio (%BF). Some cutoffs of these parameters have been identified as predictors for unfair 1-y clinical outcome: mean graft flow (MGF) less than 20 ml/min and high pulsatility index greater than 5. Other cutoffs have been found as related to postoperative angiography: MGF 15 ml/min or less and pulsatility index at least 3 (sensitivity 94%; specificity 61%); MGF less than 15 ml/min and pulsatility index greater than 3 for left coronary artery or pulsatility index greater than 5 for right coronary artery (sensitivity 96%; specificity 77%); MGF 15 ml/min or less and pulsatility index at least 5.1 left coronary artery (sensitivity 98%; specificity 26%). Hence, with the need to improve the diagnostic accuracy of TTFM, high-resolution epicardic coronary ultrasound module has been added to graft flow evaluation providing 2D ultrasound imaging (either in short-axis or long-axis) and color-flow mapping, allowing an accurate morphological evaluation of body graft and anastomosis. An intraoperative method aimed to verify coronary grafts should be easy to handle, not time consuming, minimally invasive, easily meaningful and relatively cheap; in addition, it should offer objective parameters more than qualitative criteria. We herein report the results of our experience with intraoperative graft verification with TTFM and high-resolution imaging along with a systematic review of the literature in this field with the aim to provide a road map to be followed.

There is a significant variety of vascular conduits options for coronary bypass surgery. Adequate graft selection is the most important factor for the success of the intervention. To ensure durability, permeability, and bypass function, there must be a morphological similarity between the graft and the coronary artery. The objective of this review was to analyze the morphological characteristics of the grafts that are most commonly used in coronary bypass surgery and the coronary arteries that are most frequently occluded. We included clinical information regarding the characteristics that determine the behavior of the grafts and its permeability over time. Currently, the internal thoracic artery is the standard choice for bypass surgery because of the morphological characteristics of the wall that makes less prone to developing atherosclerosis and hyperplasia. The radial and right gastroepiploic arteries are the following second and third best options, respectively. The ulnar artery is the preferred choice when other conduits are not feasible.

Objectives: The present study was designed to evaluate the association between chronic kidney disease and the endothelial function of internal thoracic artery (ITA) grafts in patients undergoing coronary bypass surgery. An isometric tension study was performed in ITA strips obtained during surgery. Concentration-response curves for acetylcholine (ACh) and sodium nitroprusside were constructed in ITA strips partially precontracted with phenylephrine under the inhibition of cyclooxygenase. The integrity of the endothelium was verified histologically by en-face staining of the luminal surface with the use of silver nitrate solution., Results: In endothelium-intact ITA strips, ACh produced a concentration-dependent relaxation in patients with glomerular filtration rate (GFR, mL/min/1.73 m 2 ) > 60. A concentration-dependent relaxation response also was observed in patients with GFR 30 to 60, but it was reduced significantly compared with those with GFR > 60. In both groups, removal of endothelium or treatment with nitric oxide (NO) synthase inhibitors almost abolished the ACh-induced relaxation. On the other hand, in patients with GFR < 30, mild contraction rather than relaxation was induced at a high concentration of ACh, which was modified neither by treatment with NO synthase inhibitors nor by removal of the endothelium. Vasodilator responses to sodium nitroprusside were comparable among the 3 groups. The relaxation of endothelium-intact strips to a peak ACh concentration correlated positively with GFR. This relationship held true in a multiple linear regression model, and interaction terms between GFR and other risk factors were not statistically significant., Conclusions: Endothelial function of ITA grafts to release NO is impaired at the time of surgery in patients with chronic kidney disease., (Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Transit time flow measurement (TTFM) is a quality control tool for intraoperative graft evaluation in coronary artery bypass graft (CABG) surgery. A critical review of the literature available using TTFM in CABG surgery is the focus of this article. The main objectives will be to detail precise parameters for flow evaluation, to show limitations of TTFM and to prove its predictive impact on postoperative graft failure rate. Publications listed in the PubMed database were reviewed, searching for intraoperative graft verification in coronary surgery by TTFM, with postoperative imaging follow-up (FU) modality and with a special focus on publications released after European guidelines from 2010. Nine included publications revealed an overall graft failure rate of ∼12%. Mean graft flow had a positive predictive value in the largest study, and cut-offs, of at least 20 ml/min for internal mammary artery (IMA) grafts, therein partially confirming guidelines, and 30-40 ml/min for saphenous venous grafts (SVGs) were proposed. An explicit correlation between graft flow, patency rate and severity of coronary stenosis, by indicating the fractional flow reserve, was found for IMA grafts. Increased pulsatility index and increased systolic reverse flow probably predict worse outcome and may help identifying competitive flow. Diastolic filling, rarely indicated, could not be confirmed as the predictive marker. No significant correlation of TTFM and graft failure rate for radial and other arterial grafts could be found, partially due to the small number of these types of grafts analysed. Larger target vessels and lower postoperative CK-MB levels may predict better graft patency rates. Low sensitivity for TTFM to reliably detect graft failure is certainly a major issue, as found in randomized analyses. However, methodical limitations and varying threshold values for TTFM render a general consensus difficult. Influence of quantity (vessel territory distribution) and quality (myocardial scar) of the graft perfusion area, on TTFM and FU outcome, was not included by anyone and should be part of future research. TTFM is probably not the tool of choice to detect progressive late graft failure of SVG. Peroperative TTFM values should be correlated with one type of conduit, differentiating between early and late graft failure (by applying a uniform, appropriated definition), to precise and confirm threshold values., (© The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)

Background: During coronary artery bypass grafting (CABG), the ratio of powers of the fundamental frequency and its first harmonic (F0/H1) in fast Fourier transformation (FFT) analysis of the graft's flow waves has been used in the field of evaluation of the patency in anastomosis. But there is no report about using the FFT method to evaluate the magnitude of competitive flow. This study is aiming at exploring the relationship between competitive flow and FFT analysis of the flow waves in left internal mammary artery (LIMA) graft, and finding a new method to evaluate the magnitude of competitive flow., Methods: At first, establishing the CABG multiscale models of different stenosis in left anterior descending artery (LAD) to get different magnitude of competitive flows. Then, calculating the models by ANSYS-CFX and getting the flow waves in LIMA. Finally, analyzing the flow waves by FFT method and comparing the FFT results with the magnitude of competitive flow., Results: There is no relationship between competitive flow and F0/H1. As for F0/H2 and F0/H3, they both increase with the reduction of the stenosis in LAD. But the increase of F0/H3 is not obviously enough and it can't identify the significant competitive flow clearly, so it can't be used as the evaluation index. It is found that F0/H2 increases obviously with the increase of the competitive flow and can identify the significant competitive flow., Conclusion: The FFT method can be used in the evaluation of competitive flow and the F0/H2 is the ideal index. High F0/H2 refers to the significant competitive flow. This method can be used during CABG to avoid the risk of competitive flow.