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Objectives: Cardiac surgery using cardiopulmonary bypass contributes to a robust systemic inflammatory process. Local intrapericardial postsurgical inflammation is believed to trigger important clinical implications, such as postoperative atrial fibrillation and postsurgical intrathoracic adhesions. Immune mediators in the pericardial space may underlie such complications., Methods: In this prospective pilot clinical study, 12 patients undergoing isolated coronary artery bypass graft surgery were enrolled. Native pericardial fluid and venous blood samples (baseline) were collected immediately after pericardiotomy. Postoperative pericardial fluid and venous blood samples were collected 48-hours after cardiopulmonary bypass and compared with baseline. Flow cytometry determined proportions of specific immune cells, whereas multiplex analysis probed for inflammatory mediators., Results: Neutrophils are the predominant cells in both the pericardial space and peripheral blood postoperatively. There are significantly more CD163 lo macrophages in blood compared with pericardial effluent after surgery. Although there are significantly more CD163 hi macrophages in native pericardial fluid compared with baseline blood, after surgery there are significantly fewer of these cells present in the pericardial space compared with blood. Postoperatively, concentration of interleukin receptor antagonist 6, and interleukin 8 were significantly higher in the pericardial space compared with blood. After surgery, compared with blood, the pericardial space has a significantly higher concentration of matrix metalloproteinase 3, matrix metalloproteinase 8, and matrix metalloproteinase 9. The same trend was observed with transformational growth factor β., Conclusions: Cardiac surgery elicits an inflammatory response in the pericardial space, which differs from systemic inflammatory responses. Future work should determine whether or not this distinct local inflammatory response contributes to postsurgical complications and could be modified to influence clinical outcomes., (© 2023 The Author(s).)

Background: Recently, there is interest in the clinical importance of monitoring abdominal muscles during respiratory failure. The clinical interpretation relies on the assumption that expiration is a passive physiologic process and, since diaphragm and abdomen are arranged in series, any inward motion of the abdominal wall represents a sign of diaphragm dysfunction. However, previous studies suggest transversus abdominis might be active even during eupnea and is preferentially recruited over the other abdominal muscles., Objective: 1) Is transversus abdominis normally recruited during eupnea? 2) What is the degree of activation of transversus abdominis during hypercapnia? 3) Does the end-inspiratory length of transversus abdominis change during hypercapnia, while diaphragm function is normal?, Methods: In 30 spontaneously breathing canines, awake without confounding anesthetic, we measured directly both electrical activity and corresponding mechanical length and shortening of transversus abdominis during eupnea and hypercapnia., Results: Transversus abdominis is consistently recruited during eupnea. During hypercapnia, transversus abdominis recruitment is progressive and significant. Throughout hypercapnia, transversus abdominis baseline end-inspiratory length is not constant: baseline length decreases progressively throughout hypercapnia. After expiration, into early inspiration, transversus abdominis shows a consistent neural mechanical post -expiratory expiratory activity (PEEA) at rest, which progressively increases during hypercapnia., Conclusion: Transversus abdominis is an obligatory expiratory muscle, reinforcing the fundamental principle expiration is not a passive process. Beyond expiration, during hypercapnic ventilation, transversus abdominis contributes as an "accessory inspiratory muscle" into the early phase of inspiration. Clinical monitoring of abdominal wall motion during respiratory failure may be confounded by action of transversus abdominis., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Objective: There is a paucity of data on the inflammatory response that takes place in the pericardial space after cardiac surgery. This study provides a comprehensive assessment of the local postoperative inflammatory response., Methods: Forty-three patients underwent cardiotomy, where native pericardial fluid was aspirated and compared with postoperative pericardial effluent collected at 4, 24, and 48 hours' postcardiopulmonary bypass. Flow cytometry was used to define the levels and proportions of specific immune cells. Samples were also probed for concentrations of inflammatory cytokines, matrix metalloproteinases (MMPs), and tissue inhibitors of metalloproteinases (TIMPs)., Results: Preoperatively, the pericardial space mainly contains macrophages and T cells. However, the postsurgical pericardial space was populated predominately by neutrophils, which constituted almost 80% of immune cells present, and peaked at 24 hours. When surgical approaches were compared, minimally invasive surgery was associated with fewer neutrophils in the pericardial space at 4 hours' postsurgery. Analysis of the intrapericardial concentrations of inflammatory mediators showed interleukin-6, MMP-9, and TIMP-1 to be highest postsurgery. Over time, MMP-9 concentrations decreased significantly, whereas TIMP-1 levels increased, resulting in a significant reduction of the ratio of MMP:TIMP after surgery, suggesting that active inflammatory processes may influence extracellular matrix remodeling., Conclusions: These results show that cardiac surgery elicits profound alterations in the immune cell profile in the pericardial space. Defining the cellular and molecular mediators that drive pericardial-specific postoperative inflammatory processes may allow for targeted therapies to reduce immune-mediated complications., (© 2022 The Author(s).)

Objective: We aimed to compare transit-time flow measurement (TTFM) parameters for on-pump (ONCAB) and off-pump (OPCAB) coronary artery bypass procedures., Methods: The database of the Registry for Quality AssESsmenT with Ultrasound Imaging and TTFM in Cardiac Bypass Surgery (REQUEST) study was retrospectively reviewed. Only single grafts were included (ie, no sequential or Y/T grafts). Primary end points were mean graft flow (MGF), pulsatility index (PI), diastolic fraction (DF), and backflow (BF). Unadjusted and propensity score-matching comparisons were performed., Results: Of 1016 patients in the REQUEST registry, 846 had at least 1 graft for which TTFM was performed. Of these, 512 patients (60.6%) underwent ONCAB and 334 (39.4%) OPCAB procedures. Mean arterial pressure (MAP) during measurements was higher in the OPCAB group. After propensity score-matching, 312 well balanced pairs were left. In these matched patients, MGF was higher for the ONCAB versus the OPCAB group (32 vs 28 mL/min, respectively, for all grafts [ P  < .001]; 30 vs 27 mL/min for arterial grafts [ P  = .002]; and 35 vs 31 mL/min for venous grafts [ P  = .006], respectively). PI was lower in the ONCAB group (2.1 vs 2.3, for all grafts; P  < .001). Diastolic fraction was slightly lower in the ONCAB group (65% vs 67.5%; P  < .001). The backflow was also lower in the ONCAB group (0.6 vs 1.3; P  < .001) with trends similar to MGF and PI for venous and arterial grafts. There were 21 (3.3%) revisions in the OPCAB group and 14 (2.1%) in the ONCAB group ( P  = .198)., Conclusions: ONCAB surgery was associated with higher MGF and lower PI values, especially in venous grafts. Different TTFM cutoff values for ONCAB versus OPCAB surgery might be considered., (© 2022 The Author(s).)

Objectives: Despite society guideline recommendations, intraoperative high-frequency ultrasound (HFUS) and transit-time flow measurement (TTFM) use in coronary artery bypass grafting (CABG) has not been widely adopted worldwide. This retrospective review of the REQUEST (REgistry for QUality assESsmenT with Ultrasound Imaging and TTFM in Cardiac Bypass Surgery) study assesses the impact of protocolled high-frequency ultrasound/TTFM use in specific technical circumstances of CABG., Methods: Three REQUEST study sub-analyses were examined: (i) For off-pump (OPCAB) versus on-pump (ONCAB) procedures: strategy changes from preoperative plans for the aorta, conduits, coronary targets and graft revisions; and for all REQUEST patients, revision rates in: (ii) arterial versus venous grafts; and (iii) grafts to different cardiac territories., Results: Four hundred and two (39.6%) of 1016 patients undergoing elective isolated CABG for multivessel disease underwent OPCAB procedures. Compared to ONCAB, OPCAB patients experienced more strategy changes regarding the aorta [14.7% vs 3.4%; odds ratios (OR) = 4.03; confidence interval (CI) = 2.32-7.20], less regarding conduits (0.2% vs 2.8%; OR = 0.09; CI = 0.01-0.56), with no differences in coronary target changes or graft revisions (4.1% vs 3.5%; OR = 1.19; CI = 0.78-1.81). In all REQUEST patients, revisions were more common for arterial versus venous grafts (4.7% vs 2.4%; OR = 2.05; CI = 1.29-3.37), and inferior versus anterior (5.1% vs 2.9%; OR = 1.77; CI = 1.08-2.89) and lateral (5.1% vs 2.8%; OR = 1.83; CI = 1.04-3.27) territory grafts., Conclusions: High-frequency ultrasound/TTFM use differentially impacts strategy changes and graft revision rates in different technical circumstances of CABG. Notably, patients undergoing OPCAB experienced 4 times more changes related to the ascending aorta than ONCAB patients. These findings may indicate where intraoperative assessment is most usefully applied., Clinical Trial Registration Number: ClinicalTrials.gov: NCT02385344., (© The Author(s) 2021. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)

Transit time flow measurement (TTFM) allows quality control in coronary artery bypass grafting but remains largely underused, probably because of limited information and the lack of standardization. We performed a systematic review of the evidence on TTFM and other methods for quality control in coronary artery bypass grafting following PRISMA standards and elaborated expert recommendations by using a structured process. A panel of 19 experts took part in the consensus process using a 3-step modified Delphi method that consisted of 2 rounds of electronic voting and a final face-to-face virtual meeting. Eighty percent agreement was required for acceptance of the statements. A 2-level scale (strong, moderate) was used to grade the statements based on the perceived likelihood of a clinical benefit. The existing evidence supports an association between TTFM readings and graft patency and postoperative clinical outcomes, although there is high methodological heterogeneity among the published series. The evidence is more robust for arterial, rather than venous, grafts and for grafts to the left anterior descending artery. Although TTFM use increases the duration and the cost of surgery, there are no data to quantify this effect. Based on the systematic review, 10 expert statements for TTFM use in clinical practice were formulated. Six were approved at the first round of voting, 3 at the second round, and 1 at the virtual meeting. In conclusion, although TTFM use may increase the costs and duration of the procedure and requires a learning curve, its cost/benefit ratio seems largely favorable, in view of the potential clinical consequences of graft dysfunction. These consensus statements will help to standardize the use of TTFM in clinical practice and provide guidance in clinical decision-making.

Objectives: Acute kidney injury (AKI) is common after cardiac surgery. We quantified the mortality and costs of varying degrees of AKI using a population-based cohort in Alberta, Canada., Methods: A cohort of patients undergoing cardiac surgery from 2004 to 2009 was assembled from linked Alberta administrative databases. AKI was classified by Kidney Disease Improving Global Outcomes stages of severity. Our outcomes were in-hospital mortality, length of stay, and costs; among survivors, we also examined mortality and costs at 365 days. Estimates were adjusted for demographic characteristics, comorbidities, and other covariates., Results: Ten thousand one hundred seventy participants were included, of whom 9771 patients were discharged to community. Overall in-hospital mortality, costs, and length of stay were 4%, 7 days, and Can $34,000, respectively. Postcardiac surgery, AKI occurred in 25%. Compared with those without AKI, AKI was independently associated with increased in-hospital mortality across severity categories, with the highest risk (adjusted odds ratio, 37.1; 95% confidence interval, 26.3-52.1; P < .001) in patients who required acute dialysis. AKI severity was associated with increased hospital days and costs, with costs ranging from 1.21 for stage 1 AKI (95% confidence interval, 1.17-1.23) to 2.74 for acute dialysis (95% confidence interval, 2.49-3.00) (P < .001) times higher than in patients without AKI, after covariate adjustment. Postdischarge to 365 days, patients with AKI continued to experience increased costs up to 1.35-fold, and patients who required dialysis acutely continued to experience a 2.86-fold increased mortality., Conclusions: AKI remains an important indicator of mortality and health care costs postcardiac surgery., (Copyright © 2020 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Background: Intraoperative graft assessment with tools like Transit Time Flow Measurement (TTFM) is imperative for quality control in coronary surgery. We investigated the variation of TTFM parameters before and after protamine administration to identify new benchmark parameters for graft quality assessment., Methods: The database of the REQUEST ("REgistry for QUality AssESsmenT with Ultrasound Imaging and TTFM in Cardiac Bypass Surgery") study was retrospectively reviewed. A per graft analysis was performed. Only single grafts (i.e., no sequential nor composite grafts) where both pre- and post-protamine TTFM values were recorded with an acoustical coupling index > 30% were included. Grafts with incomplete data and mixed grafts (arterio-venous) were excluded. A second analysis was performed including single grafts only in the same MAP range pre- and post- protamine administration., Results: After adjusting for MAP, we found a small increase in MGF (29 mL/min to 30 mL/min, p = 0.009) and decrease in PI (2.3 to 2.2, p <  0.001) were observed after the administration of protamine. These changes were especially notable for venous conduits and for CABG procedures performed on-pump., Conclusion: The small changes in TTFM parameters observed before and after protamine administration seem to be clinically irrelevant, despite being statistically significant in aggregate. Our data do not support a need to perform TTFM measurements both before and after protamine administration. A single TTFM measurement taken either before or after protamine may suffice to achieve reliable data on each graft's performance. Depending on the specific clinical situation and intraoperative changes, more measurements may be informative., Trial Registration: Clinical Trials Number: NCT02385344 , registered February 17th, 2015., (© 2021. The Author(s).)

Objectives: Factors such as more diffuse atherosclerosis, plaque instability and accelerated vascular calcification in patients with chronic and end-stage renal disease (ESRD) can potentially present intraoperative challenges in coronary artery bypass grafting (CABG) procedures. We evaluated whether patients with chronic and ESRD experienced more surgical strategy changes and/or graft revisions than patients with normal renal function when undergoing CABG procedures according to a protocol for intraoperative high-frequency ultrasound and transit-time flow measurement (TTFM)., Methods: Outcomes of CABG for patients with chronic and ESRD and patients with normal renal function enrolled in the multicentre prospective REQUEST (REgistry for QUality assESsmenT with Ultrasound Imaging and TTFM in Cardiac Bypass Surgery) study were compared retrospectively. The primary end point was frequency of intraoperative surgical strategy changes. The secondary end point was post-protamine TTFM parameters., Results: There were 95 patients with chronic and ESRD and 921 patients with normal renal function. Patients with chronic and ESRD undergoing CABG according to a protocol for intraoperative high-frequency ultrasound and TTFM had a higher rate of strategy changes overall [33.7% vs 24.3%; odds ratio (OR) = 1.58; 95% confidence interval (CI) = 1.01-2.48; P = 0.047] and greater revisions per graft (7.0% vs 3.4%; odds ratio = 2.14; 95% CI = 1.17-3.71; P = 0.008) compared to patients with normal renal function. Final post-protamine graft TTFM parameters were comparable between cohorts., Conclusions: Patients with chronic and ESRD undergoing CABG procedures with high-frequency ultrasound and TTFM experience more surgical strategy changes than patients with normal renal function while achieving comparable graft flow., Clinical Trial Registration Number: ClinicalTrials.gov NCT02385344., (© The Author(s) 2021. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)

Background: Endothelial dysfunction is an early pathogenic event in the progression of cardiovascular disease in patients with Type 2 Diabetes (T2D). Endothelial KCa2.3 and KCa3.1 K + channels are important regulators of arterial diameter, and we thus hypothesized that SKA-31, a small molecule activator of KCa2.3 and KCa3.1, would positively influence agonist-evoked dilation in myogenically active resistance arteries in T2D., Methodology: Arterial pressure myography was utilized to investigate endothelium-dependent vasodilation in isolated cremaster skeletal muscle resistance arteries from 22 to 24 week old T2D Goto-Kakizaki rats, age-matched Wistar controls, and small human intra-thoracic resistance arteries from T2D subjects. Agonist stimulated changes in cytosolic free Ca 2+ in acutely isolated, single endothelial cells from Wistar and T2D Goto-Kakizaki cremaster and cerebral arteries were examined using Fura-2 fluorescence imaging., Main Findings: Endothelium-dependent vasodilation in response to acetylcholine (ACh) or bradykinin (BK) was significantly impaired in isolated cremaster arteries from T2D Goto-Kakizaki rats compared with Wistar controls, and similar results were observed in human intra-thoracic arteries. In contrast, inhibition of myogenic tone by sodium nitroprusside, a direct smooth muscle relaxant, was unaltered in both rat and human T2D arteries. Treatment with a threshold concentration of SKA-31 (0.3 μM) significantly enhanced vasodilatory responses to ACh and BK in arteries from T2D Goto-Kakizaki rats and human subjects, whereas only modest effects were observed in non-diabetic arteries of both species. Mechanistically, SKA-31 enhancement of evoked dilation was independent of vascular NO synthase and COX activities. Remarkably, SKA-31 treatment improved agonist-stimulated Ca 2+ elevation in acutely isolated endothelial cells from T2D Goto-Kakizaki cremaster and cerebral arteries, but not from Wistar control vessels. In contrast, SKA-31 treatment did not affect intracellular Ca 2+ release by the sarco/endoplasmic reticulum Ca 2+ -ATPase (SERCA) inhibitor cyclopiazonic acid., Conclusions: Collectively, our data demonstrate that KCa channel modulation can acutely restore endothelium-dependent vasodilatory responses in T2D resistance arteries from rats and humans, which appears to involve improved endothelial Ca 2+ mobilization., Competing Interests: Declaration of competing interest None., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objectives: We evaluated the influence of transit-time flow measurement with epicardial and epiaortic high-frequency ultrasound in patients undergoing coronary artery bypass grafting procedure., Methods: The Registry for Quality Assessment with Ultrasound Imaging and Transit-time Flow Measurement in Cardiac Bypass Surgery study is a multicenter, prospective study among 7 international centers performing coronary artery bypass grafting procedures. The primary end point was any change in the planned surgical procedure. Major secondary end points consisted of the rate and reason for surgical changes related to the aorta, in situ conduits, coronary targets, and completed grafts, and the rate of in-hospital mortality and major morbidity., Results: Between April 2015 and December 2017, 1046 patients were enrolled. Of those, 1016 were included in the final analyses. Mean age was 65.9 years, 14.0% were women, and diabetes was present in 39.6%. Off-pump procedures were performed in 39.6% and bilateral internal thoracic arteries in 30.5%. The primary end point occurred in 25.2% of patients (n = 256) and in 77% (197 out of 256) this was based on transit-time flow measurement and/or high-frequency ultrasound. Surgical changes were related to the aorta in 9.9%, to in situ conduits in 2.7%, and the coronary targets in 22.6%. Graft revision occurred in 7.8%, including revisions of the proximal and/or distal anastomosis in 6.6%. In-hospital adverse event rates were 0.6% for mortality, 1.0% for cerebrovascular events, and 0.3% for myocardial infarction., Conclusions: Surgical changes related to the aorta, conduits, coronary targets, and anastomosis were made in 25% of patients. This was associated with low operative mortality and low major morbidity. Transit-time flow measurement and high-frequency ultrasound may improve the quality, safety, and efficacy of coronary artery bypass grafting procedures and should be considered as a routine procedural aspect., (Copyright © 2019 The American Association for Thoracic Surgery. All rights reserved.)

Despite there being numerous studies of intraoperative graft flow assessment by transit-time flow measurement (TTFM) on outcomes after coronary artery bypass grafting (CABG), the adoption of contemporary TTFM is low. Therefore, on 31 January 2018, a systematic literature search was performed to identify articles that reported (i) the amount of grafts classified as abnormal or which were revised or (ii) an association between TTFM and outcomes during follow-up. Random-effects models were used to create pooled estimates with 95% confidence intervals (CI) of (i) the rate of graft revision per patient, (ii) the rate of graft revision per graft and (iii) the rate of graft revision among grafts deemed abnormal based on TTFM parameters. The search yielded 242 articles, and 66 original articles were included in the systematic review. Of those articles, 35 studies reported on abnormal grafts or graft revisions (8943 patients, 15 673 grafts) and were included in the meta-analysis. In 4.3% of patients (95% CI 3.3-5.7%, I2 = 73.9) a revision was required and 2.0% of grafts (95% CI 1.5-2.5%; I2 = 66.0) were revised. The pooled rate of graft revisions among abnormal grafts was 25.1% (95% CI 15.5-37.9%; I2 = 80.2). Studies reported sensitivity ranging from 0.250 to 0.457 and the specificity from 0.939 to 0.984. Reported negative predictive values ranged from 0.719 to 0.980 and reported positive predictive values ranged from 0.100 to 0.840. This systematic review and meta-analysis showed that TTFM could improve CABG procedures. However, due to heterogeneous data, drawing uniform conclusions appeared challenging. Future studies should focus on determining the optimal use of TTFM and assessing its diagnostic accuracy., (© The Author(s) 2019. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery.)

In humans and other mammals, isocapnic hypoxia sustained for 20-60 min exhibits a biphasic ventilation pattern: initial increase followed by a significant ventilatory decline ("roll-off") to a lesser intermediate plateau. During sustained hypoxia, the mechanical action and activity of the diaphragm have not been studied; thus we assessed diaphragm function in response to hypoxic breathing. Thirteen spontaneously breathing awake canines were exposed to moderate levels of sustained isocapnic hypoxia lasting 20-25 min (80 ± 2% pulse oximeter oxygen saturation). Breathing pattern and changes in muscle length and electromyogram (EMG) activity of the costal and crural diaphragm were continuously recorded. Mean tidal shortening and EMG activity of the costal and crural diaphragm exhibited an overall biphasic pattern, with initial brisk increase followed by a significant decline ( P < 0.01). Although costal and crural shortening did not differ significantly with sustained hypoxia, this equivalence in segmental shortening occurred despite distinct and differing EMG activities of the costal and crural segments. Specifically, initial hypoxia elicited a greater costal EMG activity compared with crural ( P < 0.05), whereas sustained hypoxia resulted in a lesser crural EMG decline/attenuation than costal ( P < 0.05). We conclude that sustained isocapnic hypoxia elicits a biphasic response in both ventilation and diaphragmatic function and there is clear differential activation and contribution of the two diaphragmatic segments. This different diaphragm segmental action is consistent with greater neural activation of costal diaphragm during initial hypoxia, then preferential sparing of crural activation as hypoxia is sustained. NEW & NOTEWORTHY In humans and other mammals, during isocapnic hypoxia sustained for 20-60 min ventilation exhibits a biphasic pattern: initial increase followed by significant ventilatory decline ("roll-off"). During sustained hypoxia, the function of the diaphragm is unknown. This study demonstrates that the diaphragm reveals a biphasic action during the time-dependent hypoxic "roll-off" in ventilation. These results also highlight that the two diaphragm segments, costal and crural, show differing, distinctive contributions to diaphragm function during sustained hypoxia.

The "Achilles heel" of coronary artery bypass graft (CABG) surgery is graft patency. While long-term patency is determined by the type of conduit and the progression of graft and native vessel disease, short-term patency is affected by intra-operative technical issues. Transit-time flow measurements and epicardial ultrasound have been shown to accurately assess intra-operative graft patency. This review will examine the evidence to support the premise that intra-operative graft assessment is essential in determining graft patency and should be the standard of care when performing CABG surgery., (© 2018 Wiley Periodicals, Inc.)

Objective: To assess the prevalence and clinical significance of incidental findings identified during computed tomography imaging of coronary artery bypass grafts., Results: This prospective study includes 144 patients undergoing coronary graft patency assessment using computed tomography. Incidental findings were classified as significant if they were considered to need an immediate action or treatment, short-term work-up or follow-up, or minor. A total of 211 incidental findings were present in 109 (75.7%) patients. Seventy-one incidental findings (33.6%) were cardiac and 140 (66.4%) were extracardiac. Most common cardiac incidental findings were atrial dilatation [39 patients, 48 incidental findings (67.6%)] and aortic valve calcifications (7 patients, 9.9%). Among the 140 extracardiac incidental findings, the most common were lung nodules (51 patients, 54 nodules, 38.6%), and emphysema (21 patients, 15%). Thirty-six (25.7%) extracardiac incidental findings were significant and notably, 23 (63.9%) were lung nodules. Follow-up was recommended in 37 cases, among which all patients with significant lung nodules (23 patients, 62.2%). In conclusion, most common computed tomography incidental findings in patients with coronary grafts were lung nodules and emphysema.

Purpose of Review: The coronary artery bypass graft (CABG) operation is one of the few remaining operations/interventions on diseased arteries that are not routinely verified during or immediately after the procedure. This review answers the 'how', 'when' and 'why' of intraoperative CABG assessment., Recent Findings: More recent than new literature on this topic, is the increased interest in quality assurance of CABG. This is most likely due to reports in the last 5 years suggesting CABG superiority to percutaneous coronary intervention (PCI) for improved mid-term and long-term outcomes; for example, for patients with diabetes mellitus (Freedom Trial by Farkouh in 2012), and for patients with SYNTAX score ≥ 33 (SYNTAX Trial by Mohr in 2013). Possibly CABG is re-emerging from the era-of-better-and-better-stents and is now deemed worthy of improvement., Summary: In order to fully compliment PCI, the operative major adverse cardiac event rate of CABG must rival that of PCI. In order to reduce technical errors, it is best practice to perform intra-operative assessment of bypasses, especially since we have the tools.

Purpose: A large multicenter randomized trial (RCT) is needed to assess off-pump coronary artery bypass graft (CABG) patency when performed by skilled surgeons. This prospective multicenter randomized pilot study compares graft patency after on-pump and off-pump techniques and addresses the feasibility of such an RCT., Materials and Methods: Consecutive patients were prospectively recruited for ≥64-slice computed tomography angiography graft patency assessment 1 year after randomization to off-pump or on-pump CABG. Blinded assessment of graft patency was performed, and the results were categorized as normal, ≥50% stenosis, or occlusion. A multilevel model with random effects on the patient was used to account for correlation of results in patients with multiple grafts., Results: A total of 157 patients (3 centers, 84 off-pump and 73 on-pump patients, 512 grafts, assessability rate 98.4%) were included. Patency index (% nonoccluded grafts) was 89% for the off-pump technique and 95% for the on-pump technique (P=0.09). Patency was similar for arterial and vein grafts (both 92%; P=0.88), as well as between target territories (89% to 94%; P=0.53)., Conclusions: In this pilot study, 1-year graft patency results after off-pump and on-pump surgery were similar. This feasibility trial demonstrates that a large multicenter RCT to compare CABG patency after on-pump with that after off-pump techniques is feasible and can be reliably undertaken using computed tomography angiography.

Objectives: The purpose of this study was to compare effectiveness of the 1999 logistic EuroSCORE (LES) and of the 2012 EuroSCORE II (ESII) in a real-world patient population of 1125 patients undergoing total arterial grafting (TAG) coronary artery bypass graft (CABG) surgery., Methods: The performance of the two risk scores was compared using (i) discrimination (accuracy of discriminating non-survivors from survivors), (ii) calibration (assessment of agreement between the predicted/observed outcomes) and (iii) agreement between the two scores. By averaging medians of LES and ESII and then sub-division into 10 equal groups, actual operative mortality rate was compared with the median LES and ESII within each risk group, the difference plotted against the average risk score (as in a Bland and Altman plot), and using the traditional risk groupings for EuroSCORE of low (0-2.99), medium (3-5.99) and high risk (6.0 and above), the reclassification rate of ESII was compared with that of LES., Results: In 1125 consecutive total arterial CABG patients, demographics included: mean age 64.6 years, 79% males, 35% diabetic patients, 57% urgent/emergent patients, 37% off-pump and 77% bilateral mammary grafting. Overall operative mortality was 3.2% (36 patients). Comparison of the LES and ESII showed (i) good discrimination for both LES and ESII (area under the curve for LES was 0.85 and for ESII was 0.87); (ii) neither score was well calibrated: LES tended to overestimate and ESII underestimated risk. In general, the ESII provided a better estimate of risk in lower risk patients and LES was better for the highest risk group. (iii) In terms of agreement, in the lower four risk groups the risk was overestimated by both scores, in five of the higher six risk groups ESII underestimated risk and LES overestimated risk, and in the highest risk group LES was very close (17.2 cf. 17.7) compared with ESII (5.6 cf. 17.7). In addition, ESII downgraded risk in 96.8% of survivors and in 97.2% of non-survivors., Conclusions: In 1125 consecutive TAG CABG patients, neither LES nor ESII performed well enough to be used as a consistent risk stratification tool; LES overestimated risk but was highly accurate for the highest of 10 risk groups and ESII consistently underestimated risk in all patients., (© The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)

Coronary artery disease is the leading cause of morbidity and mortality even in the elderly population. Treatment opportunities in the elderly population are often underappreciated. Revascularization procedures (coronary artery bypass graft surgery and percutaneous coronary intervention) can be associated with important benefits in symptom control, quality of life, and long-term mortality, at an upfront cost of an increased risk of in-hospital mortality and morbidity. Risk models to assess periprocedural risk are useful. The best models would balance unique aspects of risk with the very real potential benefit of revascularization. Current models fall short in this regard. Frailty, a clinical syndrome of vulnerability, is present in 25%-50% of cardiac patients, and is associated with increased morbidity and mortality. The addition of frailty can improve the discrimination of risk models. Elderly patients commonly consider quality of life to have greater importance than mortality outcomes. Furthermore, hospital admission is associated with a reduction in mobilization, loss of muscle strength, and worsening frailty, and interferes with a fundamental value in the elderly: the maintenance of independence. Therefore, an understanding of frailty, quality of life, and other unique aspects of risk, as well as individual patient goals, can assist in further defining prognosis and refine decision-making in this important and vulnerable population., (Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Action of the uppermost medial internal intercostal muscles-the parasternals-during rapid eye movement (REM) is uncertain; no direct recordings exist of shortening of these muscles during sleep. Historically, motor inhibition of skeletal muscles during REM sleep is thought to cause global loss of chest wall muscle function, REM "atonia," with preservation of only diaphragm function. However, recent evidence during wakefulness shows parasternals as distinctive obligatory inspiratory muscles. Therefore we hypothesized that attenuation of chest wall function during sleep may spare the parasternals along with the diaphragm, as essential muscles of inspiration during REM. We studied seven canines, comparing costal and crural diaphragm and parasternal intercostal muscle function during wakefulness and non-REM (NREM) and REM sleep, during normal spontaneous sleep, continuously recording ventilation and simultaneous muscle electromyogram (EMG) and length from sonomicrometry microtransducers. Ventilation during sleep declined significantly from wakefulness. From wakefulness to NREM and REM, costal and crural tidal EMG increased, while parasternal tidal EMG was preserved unchanged. Costal and crural shortening per breath during NREM and REM did not change significantly from wakefulness. Concurrently, parasternal shortening decreased equally in both NREM and REM despite preservation of the parasternal EMG. We conclude that diaphragm and parasternals are not inhibited, and both remain active together as essential inspiratory muscles, during REM sleep. The lesser contraction of parasternal intercostals compared with diaphragm may be attributed to net changes in mechanics affecting the chest wall during sleep., (Copyright © 2016 the American Physiological Society.)

Dissection of the left main coronary artery during coronary artery bypass graft (CABG) surgery is a rare, potentially lethal complication, usually diagnosed at post-mortem. During the cross-clamp period of a 4-vessel coronary artery bypass graft procedure in a 74-year old hypertensive woman, retrograde dissection occurred in a diffusely diseased marginal artery when perfused with cardioplegic solution at a pressure of 140-150 mmHg through a vein graft. The dissection extended back to the left main artery, included the posterior proximal ascending aorta and then down the left anterior descending artery (LAD). Transoesophageal echocardiography (TOE) confirmed the left main dissection and showed anterior-septal-lateral akinesis in a previously normally functioning left ventricle (LV). The circumferentially calcified proximal LAD was grafted with a saphenous vein by carving an oval area of calcium creating an elliptical opening in the artery wall. Normal LV function returned and, in the area of the left main dissection, there was only thickening with no colour flow. Eight months postoperatively cardiac catheterization showed normal LV function, patent vein grafts to the right coronary artery and proximal LAD, left internal mammary artery to distal LAD and an occluded sequential marginal vein graft. Twelve years postoperatively, the patient is well with Class I angina, on medication. There is no previous documentation of a diagnosed and successfully treated left main dissection during CABG surgery. Since this case using the technique of creating an oval opening in a circumferentially calcified coronary artery (with an otherwise satisfactory lumen), the author has been using this technique to bypass otherwise non-bypassable arteries; this technique may be useful to help patients with severe calcific coronary artery disease., (© The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)

Objective: At this consensus conference, we developed evidence-informed consensus statements and recommendations on the practice of off-pump coronary artery bypass graft (OPCAB) by systematically reviewing and performing meta-analysis of the randomized controlled trials (RCTs) comparing OPCAB and conventional coronary artery bypass (CCAB)., Methods: All RCTs of OPCAB versus CCAB through April 2013 were screened, and 102 relevant RCTs (19,101 patients) were included in a systematic review and meta-analysis (15 RCTs of 9551 high-risk patients; and 87 RCTs of 9550 low-risk patients) in accordance with the Cochrane Collaboration and PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) methodology. Consensus statements for the risks and benefits of OPCAB surgery in mortality, morbidity, and resource use were developed based on best available evidence., Results: Compared to CCAB, it is reasonable to perform OPCAB to reduce risks of stroke [class IIa, level of evidence (LOE) A], renal dysfunction/failure (class IIa, LOE A), blood transfusion (class I, LOE A), respiratory failure (class I, LOE A), atrial fibrillation (class I, LOE A), wound infection (class I, LOE A), ventilation time, and ICU and hospital length of stay (class I, LOE A). However, OPCAB may be associated with a reduced number of grafts performed (class I, LOE A) and with diminished graft patency (class IIa, LOE A, with increased coronary reintervention at 1 year and beyond (class IIa, LOE A), as well as increased mortality at a median follow-up of 5 years (class IIb, LOE A)., Conclusions: OPCAB compared with CCAB may improve outcomes in the short-term (stroke, renal dysfunction, blood transfusion, respiratory failure, atrial fibrillation, wound infection, ventilation time, and length of stay). However, over the longer-term, OPCAB may be associated with reduced graft patency, and increased risk of cardiac re-intervention and death.

Objective: Coronary artery bypass graft (CABG) surgery with arterial conduits is considered optimal. A deterrent to bilateral internal thoracic artery (BITA) grafting is the risk of deep sternal wound infection (DSWI). We introduced infection prevention measures sequentially, attempting to reduce DSWIs. The aim was to determine (1) if the absence of DSWIs in the last 469 of 1001 consecutive operations was significant; (2) which measures explained the change; and (3) the impact of diabetes., Methods: The measures included internal thoracic artery (ITA) skeletonization, no bone wax, wound irrigation, 1 observer per case, harmonic scalpel harvest of ITAs, vancomycin paste on sternal marrow, iodine-impregnated skin drapes, chlorhexidine-alcohol skin preparation, no BITA grafts in obese, diabetic women, more off-pump procedures, aseptic wound care, and marrow irrigation before sternal approximation., Results: Mean age was 65±10.4 years, 78% were male, 34% had diabetes, and 34% were obese. The first 532 patients had 16 DSWIs (3%) and the subsequent 469 had none (P<.001). Analysis of the data suggested that the first 11 measures likely contributed to the absence of DSWI and less likely, the twelfth. Key measures were likely chlorhexidine-alcohol use and avoidance of BITAs in obese diabetic women who had a 10-fold higher DSWI rate than the other patients (21.4% vs 2.0%). Other diabetics, including obese men, had no increased risk of DSWI., Conclusions: The measures applied caused a substantial reduction in DSWIs. Key measures included the use of chlorhexidine-alcohol and avoidance of BITA grafting in obese diabetic females. These measures reduced DSWIs after BITA grafting in most diabetics., (Copyright © 2014 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Objectives: Skeletonization of the internal mammary artery (IMA) facilitates arterial grafting and has been shown to reduce deep sternal infection but is more time-consuming and tedious than pedicle harvest. We wished to determine if use of harmonic technology (HT) facilitates skeletonization of the IMA and is as safe as the conventional technique of skeletonization., Methods: In a consecutive series of 1057 patients with isolated coronary artery bypass graft (CABG) surgery from 2003 to 2013, adverse events and recorded harvest times were compared between harmonic (965 patients) and non-harmonic patients (86 patients)., Results: HT was used to harvest 1640 IMAs in 965 (91%) of 1057 consecutive CABG patients and skeletonization with the traditional technique (use of an electrocautery tip as a dissector) was used to harvest 147 IMAs in 86 patients. Six patients had no IMA harvested with this surgery (4 patients had an IMA used from a previous CABG, 1 had no disease of the left anterior descending coronary artery and 1 patient was in cardiogenic shock precluding IMA use). Excluding patients with single-vessel disease, 730/987 (74%) of patients received bilateral IMAs. Demographics of patients with and without harmonic skeletonization, respectively, were the following: mean age: 64.7 vs 67.7 years; diabetes: 33 vs 34%; women: 21 vs 26% and median European System for Cardiac Operative Risk Evaluation: 2.9 vs 3.2. The mean harvest time for 77 non-harmonic skeletonized mammary arteries (49 surgeries) was 32.2 min (95% confidence interval (CI): 30.1, 34.3), for harmonic skeletonized arteries after 450 surgeries was 28.4 min, (95% CI: 27.8, 29.1) and in the last 100 IMAs harvested for the isolated harmonic device use/mammary was 15.4 min (95% CI: 14.0, 16.7). Major adverse events for patients with and without harmonic skeletonization, respectively, were: reoperation for bleeding: 2.7 vs 3.5% (difference = 0.8%, 95% CI: -3.2, 4.8); damaged mammaries: 0.4 vs 0.7% (difference = 0.3%, 95% CI: -1.0, 1.7); deep sternal infection: 1.6 vs 1.2% (difference = -0.4%, 95% CI: -2.8, 2.0) and perioperative infarction: 1.7 vs 2.3% (difference = 0.7%, 95% CI: -2.6, 4.0)., Conclusion: In this largest series to date of harmonic IMA skeletonization, this technique results in rare damage, is quicker and with a comparable adverse event rate compared with the non-harmonic method.

Objective: Coronary artery bypass grafting (CABG) with incomplete revascularization (ICR) is thought to decrease survival. We studied the survival of patients with ICR undergoing total arterial grafting., Methods: In a consecutive series of all-comer 1000 patients with isolated CABG, operative and midterm survival were assessed for patients undergoing complete versus ICR, with odds ratios and hazard ratios, adjusted for European System for Cardiac Operative Risk Evaluation category, CABG urgency, age, and comorbidities., Results: In this series of 1000 patients with 98% arterial grafts (2922 arterial, 59 vein grafts), 73% of patients with multivessel disease received bilateral internal mammary artery grafts. ICR occurred in 140 patients (14%). Operative mortality was 3.8% overall, 8.6% for patients with ICR, and 3.2% for patients with complete revascularization (P = .008). For operative mortality using multivariable logistic regression, after controlling for European System for Cardiac Operative Risk Evaluation category (P < .001) and CABG urgency (P = .03), there was no evidence of a statistically significant increased risk of death due to ICR (odds ratio, 1.73; 95% confidence interval, 0.80-3.77). For midterm follow-up (median, 54 months [interquartile range, 27-85 months]), after controlling for European System for Cardiac Operative Risk Evaluation category (P < .001) and comorbidities (P = .017) there was a significant interaction between age ≥ 80 years and ICR (P = .017) in predicting mortality. The adjusted hazard ratio associated with ICR for patients older than age 80 years was 5.7 (95% confidence interval, 1.8-18.0) versus 1.2 (95% confidence interval, 0.7-2.1) for younger patients., Conclusions: This is the first study to suggest that ICR in patients with mostly arterial grafts is not associated with decreased survival perioperatively and at midterm in patients younger than age 80 years. Arterial grafting, because of longevity, may balance survival between complete revascularization and ICR., (Crown Copyright © 2014. Published by Mosby, Inc. All rights reserved.)

Background: The efficacy of coronary artery bypass graft surgery (CABG) and percutaneous coronary intervention (PCI) in patients with coronary artery disease has been well defined by randomized controlled trials. However, patients with severe left ventricular dysfunction (ejection fraction <35%) were underrepresented in these trials, and management of these complex patients remains unclear. The purpose of this study was to compare the outcomes of patients with coronary artery disease and left ventricular dysfunction undergoing CABG versus PCI., Methods: The Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH), a clinical data collection and outcome monitoring initiative for the province of Alberta, Canada, was used to identify 2925 patients with coronary artery disease and left ventricular dysfunction undergoing CABG (n = 1,326) or PCI (n = 1,599) between 1995 and 2008. Patients were propensity matched to obtain comparable subgroups among left ventricular dysfunction patients., Results: Cox proportional hazard analysis of the propensity-matched subgroups identified that CABG was significantly associated with lower rates of repeat revascularization and better survival compared with PCI at 1, 5, 10, and 15 years. Other significant independent predictors of poor long-term survival included age, renal failure, heart failure, diabetes mellitus, peripheral vascular disease, prior myocardial infarction, left main coronary artery disease, and prior CABG., Conclusions: For patients with coronary artery disease and left ventricular dysfunction, CABG was associated with lower rates of repeat revascularization and improved survival over PCI, after adjustment for baseline risk profile differences. Further research exploring the factors leading to use of a particular revascularization modality in this patient population is required., (Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Purpose of Review: Arterial grafting is superior to venous grafting in coronary artery bypass graft surgery with respect to graft patency and long-term patient outcome, but it may be difficult to achieve complete arterial revascularization., Recent Findings: Use of arterial grafts, especially bilateral internal mammary artery grafts, is not common, whereas there are clear indications that it may increase survival. Definitions of complete revascularization are varied and confusing, making study comparisons difficult. Technical challenges in complete revascularization with arterial grafts can be minimized by surgical techniques. Competitive flow in moderately stenosed coronary arteries grafted with arterial conduits may result in reduced patency. While internal mammary arteries may be used in arteries with at least 60% stenosis, radial artery and gastroepiploic grafts are best placed onto coronaries with severe stenosis. Moderate lesions in the left coronary circulation should be bypassed, but right coronary artery lesions can be left untouched as there is minimal progression over time. Complete revascularization may not be necessary or possible in every patient because of technical challenges., Conclusion: Complete revascularization with arterial grafts presents both technical and physiological challenges. However, with techniques to maximize length of arterial conduits, knowledge of competitive flow and which moderate lesions should be addressed, complete revascularization with arterial grafts can be accomplished in the majority of patients, notwithstanding it may not be possible or even indicated for every patient.

Since first introduced in the mid-1960s, coronary artery bypass grafting (CABG) has become the standard of care for patients with coronary artery disease. Surprisingly, the fundamental surgical technique itself did not change much over time. Nevertheless, outcomes after CABG have dramatically improved over the first 50 years. Randomized trials comparing percutaneous coronary intervention (PCI) to CABG have shown converging outcomes for select patient populations, providing more evidence for wider use of PCI. It is increasingly important to focus on the optimization of the short- and long-term outcomes of CABG and to reduce the level of invasiveness of this procedure. This review provides an overview on how new techniques and widespread consideration of evolving strategies have the potential to optimize outcomes after CABG. Such developments include off-pump CABG, clampless/anaortic CABG, minimally invasive CABG with or without extending to hybrid procedures, arterial revascularization, endoscopic vein harvesting, intraprocedural epiaortic scanning, graft flow assessment, and improved secondary prevention measures. In addition, this review represents a framework for future studies by summarizing the areas that need more rigorous clinical (randomized) evaluation.

Surgical treatment for angina pectoris was first proposed in 1899. Decades of experimental surgery for coronary artery disease finally led to the introduction of coronary artery bypass grafting (CABG) in 1964. Now that we are approaching 50 years of CABG experience, it is appropriate to summarize the advancement of CABG into a procedure that is safe and efficient. This review provides a historical recapitulation of experimental surgery, the evolution of the surgical techniques and the utilization of CABG. Furthermore, data on contemporary clinical outcomes are discussed.

Objectives: The management strategy remains controversial for patients presenting with type A acute aortic dissection with cerebrovascular accident or coma. The present study aimed to help guide surgeons treating these high-risk patients., Methods: Of 1873 patients with type A acute aortic dissection enrolled in the International Registry for Acute Dissection, 87 (4.7%) presented with cerebrovascular accident and 54 (2.9%) with coma. The hospital and 5-year results were stratified by the presence and type of brain injury (no injury vs stroke vs coma) and management type (medical vs surgical). Independent predictors of short- and mid-term survival were identified., Results: Presentation with shock, hypotension, or tamponade (46.8% vs 25.2%; P < .001) and arch vessel involvement (55.0% vs 36.1%; P < .001) was more likely in patients with brain injury. Surgical management was avoided more often in patients with coma (33.3%) or cerebrovascular accident (24.1%) than in those without brain injury (11.1%; P < .001). The overall hospital mortality was 22.7% without brain injury, 40.2% with cerebrovascular accident, and 63.0% with coma (P < .001). Mortality varied among the management types for both cerebrovascular accident (76.2% medical vs 27.0% surgical; P < .001) and coma (100% medical vs 44.4% surgical; P < .001). Postoperatively, cerebrovascular accident and coma resolved in 84.3% and 78.8% of cases, respectively. On logistic regression analysis, surgery was protective against mortality in patients presenting with brain injury (odds ratio 0.058; P < .001). The 5-year survival of patients presenting with cerebrovascular accident and coma was 23.8% and 0% after medical management versus 67.1% and 57.1% after surgery (log rank, P < .001), respectively., Conclusions: Brain injury at presentation adversely affects hospital survival of patients with type A acute aortic dissection. In the present observational study, the patients selected to undergo surgery demonstrated improved late survival and frequent reversal of neurologic deficits., (Copyright © 2013 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

Background: Although bilateral internal thoracic artery (BITA) grafting in coronary artery bypass grafting (CABG) is associated with low morbidity and good long-term results, controversy exists about the age after which BITA grafting is no longer beneficial. We sought to determine if such an age cutoff point exists., Methods: The study cohort consisted of 5,601 consecutive patients from a cardiac surgery registry who underwent isolated CABG (1,038 [19%] BITA grafts, 4,029 [72%] single internal thoracic artery [SITA] grafts, 534 [10%] vein-only grafts) between 1995 and 2008. A Cox model was used to compare survival by use of bilateral, single, or no internal thoracic artery (ITA) grafts, adjusting for baseline clinical and demographic characteristics., Results: Mean follow-up was 7.1 years. Patients undergoing BITA grafting had the lowest 1-year mortality (2.4% versus 4.3% SITA grafting and 8.2% vein-only grafting; p < 0.0001). Relative to SITA grafting, a crude survival benefit of 54% existed for BITA grafting (hazard ratio [HR] 0.46; 95% confidence interval [CI], 0.37 to 0.57; p < 0.0001) with worse survival for vein-only grafts (HR, 1.16; 95% CI, 0.99 to 1.37; p = 0.07). After adjustment, the benefit of BITA grafting was no longer statistically significant (HR, 0.87; 95% CI, 0.69 to 1.08; p = 0.2). However age may be an effect modifier: a spline analysis plotting HR (BITA grafting versus SITA grafting) against age suggested a potential survival advantage associated with BITA grafting in patients younger than 69.9 years., Conclusions: Bilateral internal thoracic artery grafting is a reasonable revascularization strategy in suitable patients up to age 70 years. As benefits of arterial grafting become more obvious over time, a longer period of follow-up will be needed to confirm the advantage of a BITA grafting strategy. In the meantime the BITA grafting advantage for patients older than 70 years is not clear., (Copyright © 2011 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)