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Cardiac surgeons are occasionally faced with ascending aorta graft kinking following ascending aorta replacement. Although it may be difficult to precisely assess the correct length of the graft during aortic clamping, while performing proximal and distal graft anastomoses on an empty heart, the major reason for graft kinking is its excessive length. Haemolytic anaemia, graft thrombosis or even heart failure have been reported as a consequence of unrecognised and uncorrected kinking of the ascending aortic graft. This paper describes a modification and improvement of an old aortic graft non-clamping technique to solve the problem of kinked tubular graft without resuming cardiopulmonary bypass.

There is still debate whether radial artery (RA) conduits are better grafts then saphenous vein grafts (SVG) as a second conduit in coronary artery bypass grafting (CABG) surgery. Although it has been confirmed that RA grafts have significantly better patency over years, only some observational studies have associated RA use with reduced all-cause mortality. So far, no randomized controlled trial (CRT) has confirmed significantly better survival for RA graft recipients versus SVG recipients. Therefore, we have to wait for the results of the ongoing ROMA (CRT) study, to draw relevant conclusions about the impact of the second graft on long-term survival in patients undergoing CABG surgery.

Background/Aim. The treshold that defines a low, moderate or high-risk patients is not uniformly determined for the European System for Cardiac Operative Risk Evaluation (EuroSCORE II) by literature at present. The aim of this study was to suggest risk groups categorization within EuroSCORE II risk statification model. Methods. A 7,641 consecutive patients were scored preoperatively using EuroSCORE II. The end point for the study was in-hospital mortality accross the risk group categories. Patients with EuroSCORE II values of ? 2.50, > 2.50?6.50%, and > 6.50% were defined to be at low, moderate, and high perioperative risk, respectively. Discriminative power of the model was tested by calculating the area under the receiver operating characteristic curve (AUC). The calibration of the model was assessed by Hosmer-Lemeshow statistics, and with observed/expected (O/E) mortality ratio. Results. Inhospital mortality observed in our sample was 3.85% (295 out of 7,641 patients). The EuroSCORE II discriminative power was acceptable (AUCs > 0.70) for the low and high risk groups, while it failed to confirm good discrimination in the moderate risk group. Hosmer-Lemeshow statistics confirmed good calibration across risk group categories. The O/E mortality ratio failed to confirm good calibration in the low and high risk group (slight, but significant underprediction ratio of 1.24; 95% confidence interval 1.05?1.43), but confirmed good calibration in all three subcategories of the high risk group. Conclusion. The results of this study showed an acceptable overall performance of the Euro- SCORE II in terms of discrimination and accuracy of model predictions for perioperative mortality across risk group categories. Validation of EuroSCORE II performances across risk group categories needs to be further studied for a continuous improvement of patients' risk stratification before planned cardiac surgery.

Background/Aim. A protection of heart and other organs from ischemic-reperfusion injuries can be provided by remote ischemic preconditioning (RIPC) by brief episodes of ischemia and reperfusion in distant tissues. The aim of this study was to assess effects of RIPC on early outcomes in patients underwent coronary bypass surgery (CABG) following acute coronary syndrome without persistent ST segment elevation (NSTEMI ACS). Methods. This trial included 42 patients randomized into two groups: the group 1 received RIPC and the group 2 was without RIPC (control group). Pre-, intra- and postoperative parameters were compared but primary endpoint was myocardial injury reflected as value of troponin I measured preoperatively and 1, 6, 12, 24, 48 and 72 h postoperatively. The secondary endpoints were hemodynamic parameters, blood loss, intensive care unit stay, mortality etc. Results. The groups 1 and 2 were similar in preoperative characteristics including age, New York Heart Association (NYHA) class, EuroSCORE II, left ventricular ejection fraction. The only significant difference between groups was for triple vessel coronary disease with dominance in the RIPC group [20 (100%) vs. 17 (77.3%), p = 0.049]. Cardiopulmonary bypass time [mean (? standard deviation): 83.0 (22.9) vs. 67.0 (17.4) minutes, p = 0.015], cross clamp time [57.9 (15.4) vs. 44.3 (14.3) minutes, p = 0.005] and number of conduits [median (25?75th percentile): 23.5(3?4) vs. 3(2?3), p = 0.002] were different. Other intra- and postoperative variables did not differ between groups. There were no differences in C reactive protein levels and postoperative hemodynamic parameters. Average troponin values in all time points revealed no significant differences between groups (p0h = 0.740, p1h = 0.212, p6h = 0.504, p12h = 0.597, p24h = 0.562, p48h = 0.465 and p72h = 0.715, respectively). Furthermore, there were no significant differences in adverse events, hospital stay and mortality between groups. Conclusion. Treatment with RIPC during CABG following NSTEMI ACS did not provide better myocardial protection and hemodynamics characteristics but further larger randomized studies are needed t. prove its real value.

Background Controversies exist how to predict medium term mortality (Mt) in diabetics (DM) with 3 vessel (3VD) and/or left main (LM) disease undergoing myocardial revascularization ranging from Syntax Score II (SSII) where DM was not predicative variable up to FREEDOM formula which was derived, just from population with DM (without LM), having DM patients (Pts) requirement of insulin as one of predicative variable. Purpose To compare predicative power of SSII, FREEDOM and formula developed in our institution in Pts post first isolated CABG with 3VD and/or LM with DM. Methods From our prospective data base of 2455 consecutive pts who had the first isolated CABG in the period 01/2012–12/2014 with complex Ischemic Heart Disease with 100% follow up of 4 years all-cause Mt we created by random sampling Training (1321; Mt:10.4%; DM 511; Mt:13.3%) and Validation (1134; Mt:10.0%; DM 414; Mt: 11.8%) sets. After deriving predicative formula (Cox regression) from training population we validated FREEDOM, SSII and Our Formula in 414 pts with DM from the Validation set. Results Characteristics of pts, our formula, predicating power by C Statistics, Calibration plots and Brier scores are presented in Picture 1. Conclusions FREEDOM formula designed just for DM pts with complex Ischemic Heart Disease without LM had the smallest standard error in the estimate, but moderate C statistics as Syntax Score II and our formula which may be used for pts with and without DM and 3VD and/or LM. Picture 1 Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Ministry of education, science and technology development, Republic of Serbia

Background Freedom formula (FF) was derived very recently to assist in decision making by Heart Team in patients (Pts) with diabetes (DM) who are in need for myocardial revascularization (Percutaneous Coronary Intervention or Coronary artery bypass grafting (CABG)) due to complex ischemic Heart disease (but without left main steam disease (LM)). In external validation moderate C statistics values were obtained. Purpose To validate FF predictive value in Pts with DM and more complex patients (three vessel (3VD) and/or LM as well lower left ventricular ejection fraction (LVEF)) than in FREEDOM population. Methods From our prospective data base of 2455 consecutive pts who had the first isolated CABG in the period 01/2012–12/2014 with 3VD and/or LM with 100% follow up of 4 years All-cause Mortality (Mt) we retrieved 925 pts with DM. Results DM was present in 925 Pts (Mt: 12.6%). On insulin were 318 (34.3%; Mt 14.5%). We analysed the predicative value of FF in the whole group (925) of pts with DM as well as in subgroups with LM (294) and without LM (631; most similar to original Freedom population), separately. Characteristics of pts, Freedom formula, predicating power by C Statistics, Calibration plots and Brier scores are presented in Picture 1. Conclusions Our external validation of FF was almost identical as previous published one. Furthermore, the FF may be of value even in pts with LM disease and other vessels involved. Of note our pts as seen by combined LVEF, ClCr and LM were sicker than pts in FREEDOM. Picture 1 Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Ministry of education, science and technological development, Republic of Serbia

Background/Aim. The EuroSCORE II has recently been developed with an idea to provide better accuracy in prediction of perioperative mortality in the patients who underwent open heart surgery. The aim of this study was to validate clinical performances of the European System for Cardiac Operative Risk Evaluation (EuroSCORE) II risk stratification model in the Serbian adult cardiac surgical population undergoing open heart surgery. Methods. The Euro- SCORE II values on 10,048 consecutive patients undergoing major adult cardiac surgery from 1st January 2012 to 31st March 2017, were prospectively calculated and entered the institutional database. The discriminative power of the model was tested by calculating the area under the receiver operating characteristic curve (AUC). The calibration of the model was assessed by the Hosmer-Lemeshow (H-L) statistics and the observed to expected (O/E) mortality ratio. The patients with the EuroSCORE II values of 0.5?2.50%, > 2.50?6.50%), and > 6.50% were defined to be at low, moderate, and high perioperative risk, respectively. Results. The observed in-hospital mortality was 3.86% (388 of 10,048) and the mean predicted mortality by the Euro- SCORE II was 3.61%. The discriminatory power was very good for the entire cohort as well as for all subgroups [coronary, valve(s), combined (coronary plus valve), aortic and other] of performed cardiac procedures (all AUCs > 0.75). The H-L test confirmed good calibration only for category other cardiac procedures. The O/E mortality ratio confirmed good calibration for the whole sample [O/E ratio 1.07, 95% confidence interval (CI) 0.96?1.18] and for all subgroups of performed cardiac procedures, excluding significant underprediction of mortality for aortic surgery (O/E ratio 1.64; 95% CI 1.31?1.97). The EuroSCORE II overestimated perioperative risk in a low and underestimated perioperative risk in a high risk group, with acceptable discrimination (both AUCs = 0.72). On the contrary, the O/E mortality ratio confirmed good calibration for all three subcategories of high risk group. Conclusion. The results of our study confirmed acceptable overall performances of the EuroSCORE II risk stratification model in terms of discrimination and the accuracy of model when applied to the contemporary Serbian cardiac surgical cohort undergoing open heart surgery at our Institute.

Objective To compare and validate the original EuroSCORE risk stratification models with the renewed EuroSCORE II model in a contemporary cardiac surgical practice. Design A consecutive observational study to validate EuroSCORE II performances, conducted as retrospective analysis of prospectively collected data. Setting A tertiary university institute for cardiovascular diseases. Participants Adult patients undergoing cardiac surgery between January and December 2012. Methods One thousand eight hundred sixty-four consecutive patients were scored preoperatively using additive and logistic EuroSCORE as well as EuroSCORE II. The discriminative power of the EuroSCORE models was tested by calculating the area under the receiver operating characteristic curve (AUC). The calibration of the models was assessed by Hosmer-Lemeshow statistics and with observed-to-expected mortality ratio. Measurements and Main Results The in-hospital overall mortality was 3.65%, with predicted mortalities according to additive EuroSCORE, logistic EuroSCORE, and EuroSCORE II of 5.14%, 6.60%, and 3.51%, respectively. The observed-to-expected (O/E) mortality ratio confirmed good calibration for the entire cohort only for EuroSCORE II (1.05, 95% confidence interval 0.81 – 1.29). Hosmer-Lemeshow test confirmed overall good calibration only for additive EuroSCORE (p = 0.129). The EuroSCORE II confirmed very good discriminatory power for a prolonged intensive care unit (ICU) stay of>2 days and>5 days (AUCs>0.75). Acceptable discriminatory power was confirmed for a prolonged postoperative stay of>7 days and>12 days (AUCs>0.70). Conclusion EuroSCORE II confirmed very good discriminatory capacity, good calibration ability (O/E mortality ratio), and good capability to predict prolonged ICU and postoperative stays in a contemporary patient cohort undergoing cardiac surgery.

Surgery for acute aortic dissection is challenging, especially in cases of cerebral malperfusion. Should we perform only the aortic repair, or should we also reconstruct the arch vessels when they are severely affected by the disease process? Here we present a case of acute aortic dissection with multiple tears that involved the brachiocephalic artery and caused cerebral and right upper-extremity malperfusion. The patient successfully underwent complete replacement of the brachiocephalic artery and the aortic arch during deep hypothermic circulatory arrest, with antegrade cerebral protection. We have found this technique to be safe and reproducible for use in this group of patients.

Background/Aims: Study elucidates and compares the mitochondrial bioenergetic-related molecular basis of sevoflurane and propofol cardioprotection during aortic valve replacement surgery due to aortic valve stenosis. Methods: Twenty-two patients were prospectively randomized in two groups regarding the anesthetic regime: sevoflurane and propofol. Hemodynamic parameters, biomarkers of cardiac injury and brain natriuretic peptide (BNP) were measured preoperatively and postoperatively. In tissue samples, taken from the interventricular septum, key mitochondrial molecules were determined by Western blot, real time PCR, as well as confocal microscopy and immunohisto- and immunocyto-chemical analysis. Results: The protein levels of cytochrome c oxidase and ATP synthase were higher in sevoflurane than in propofol group. Nevertheless, cytochrome c protein content was higher in propofol than sevoflurane receiving patients. Propofol group also showed higher protein level of connexin 43 (Cx43) than sevoflurane group. Besides, immunogold analysis showed its mitochondrial localization. The mRNA level of mtDNA and uncoupling protein (UCP2) were higher in propofol than sevoflurane patients, as well. On the other hand, there were no significant differences between groups in hemodynamic assessment, intensive care unit length of stay, troponin I and BNP level. Conclusions: Our data indicate that sevoflurane and propofol lead to cardiac protection via different mitochondrially related molecular mechanisms. It appears that sevoflurane acts regulating cytochrome c oxidase and ATP synthase, while the effects of propofol occur through regulation of cytochrome c, Cx43, mtDNA transcription and UCP2. Copyright (C) 2012 S. Karger AG, Basel Ministry of Education and Science [173055, 173054]

Background There is ongoing debate regarding the efficacy of the radial artery (RA) as an aortocoronary conduit, with few solid data regarding long-term clinical results. We sought to determine if the use of the RA as the second arterial conduit, beside left internal thoracic artery (LITA), would improve long-term clinical outcome after CABG as compared to saphenous vein graft (SVG). Methods Between March 2001 and November 2003, 200 patients underwent isolated CABG and were randomized in 1:1 fashion to receive either LITA and RA grafts or LITA and SVGs. The primary end point was composite of cardiovascular mortality, non-fatal myocardial infarction and need for repeat myocardial revascularization (either surgical or percutaneous). Results There was no significant difference in absolute survival, with 12 deaths in each group during the study period (log rank = 0.01, p = 0.979). There were 3 and 2 cardiac deaths in RA and SVG groups, respectively. There was no difference in long-term clinical outcome between the groups (log rank = 0.450, p = 0.509). Eleven patients in RA group had one or more non-fatal events; 7 patients suffered a myocardial infarction, 9 patients underwent percutaneous coronary angioplasty, and 1 patient required redo coronary surgery. Likewise, 13 patients in SVG group had non-fatal event; 7 patients had myocardial infarction, 13 patients had percutaneous coronary intervention and 3 patients required redo coronary surgery. Angiograms were performed in 23 patients in RA group (patency rate 92 %) and 24 in SVG group (patency rate 86 %) (p = 0.67). Conclusion In this small randomised study our data indicate that there is no difference in the 8 year clinical outcomes in relatively young patients between those having a RA or a saphenous vein graft used as a second conduit, beside LITA, for surgical myocardial revascularisation.

Coronary artery bypass grafting (CABG) is the standard surgical procedure for the treatment of advanced coronary artery disease. CABG surgery has been demonstrated to improve symptoms and, in specific subgroups of patients, to prolong life. Despite its success, the long-term outcome of coronary bypass surgery is strongly influenced by the fate of the vascular conduits used. Impressive long-term disease-free patency rate of the left internal thoracic artery-left anterior descending coronary artery (LITA-LAD) graft, coupled with proven long-term survival benefits, has led to its becoming a 'golden standard' of CABG. Previous long-term studies have also shown unsatisfactory patency of saphenous vein grafts used for myocardial revascularization, compared with internal thoracic artery grafts. Thus, the use of arterial conduits has expanded beyond the internal thoracic arteries (ITAs) to include the right gastroepiploic artery, the inferior epigastric artery, and the radial artery. The assumption is that although the performance of one or two arterial ITA graft is superb, more arterial grafts should perform better in the long-term follow-up. Several studies concerning the use of the radial artery bypass grafts have documented excellent clinical results and satisfactory short-term as well as mid-term patency rates at restudy angiography, supporting its continued use as a bypass conduit. However, a note of caution concerning radial artery conduit patency rate have appeared in few recent reports. Thus, in this paper, we summarize the current evidence about the radial artery as a conduit in CABG surgery, with special emphasis on the clinical results.

Coronary artery bypass grafting (CABG) is the standard surgical procedure for the treatment of advanced coronary artery disease. CABG surgery has been demonstrated to improve symptoms and, in specific subgroups of patients, to prolong life. Despite its success, the long-term outcome of coronary bypass surgery is strongly influenced by the fate of the vascular conduits used. Previous long-term studies have shown unsatisfactory patency of saphenous vein grafts used for myocardial revascularisation, compared with internal mammary artery grafts. Recently, the use of radial artery for CABG has enjoyed a revival, on the basis of the belief that it will help improving long-term results of coronary operations. The recent reports of encouraging mid-term and long-term patency rates of the radial artery, supports its continued use as a bypass conduit. In this paper, we review the current knowledge about the radial artery as a bypass graft, with special emphasis on the clinical results. Hirurška revaskularizacija miokarda je standardna procedura u tretmanu uznapredovale koronarne bolesti. Dokazano je da koronarna hirurgija uklanja simptome i produžava život određenih kategorija koronarnih bolesnika. Dugotrajni rezultati hirurške revaskularizacije miokarda u velikoj meri ovise o promenama koje se vremenom javljaju na upotrebljenom graftu. Studije dugoročnog praćenja operisanih bolesnika potvrdile su izuzetan kvalitet i prednost grafta unutarnje torakalne arterije u odnosu na venski graft. U skorije vreme obnovljeno je interesovanje za graft radijalne arterije, sa uverenjem da će njegova primena omogućiti bolje dugoročne rezultate. U poslednje vreme prikazani su radovi koji potvrđuju izuzetnu kratkoročnu i dugoročnu prohodnost grafta radijalne arterije i govore u prilog intenzivnije primene toga grafta u hirurškoj revaskularizaciji miokarda. Na prikaz je pregled sadanjih saznanja o radijalnoj arteriji kao graftu u kardiohirurgiji, sa posebnim osvrtom na kliničke rezultate.

The pedicled left internal thoracic artery graft is the mandatory conduit in coronary artery bypass surgery. A grossly emphysematous lung may sometimes present a significant problem for positioning of the pedicled left internal thoracic artery conduit. An inverted pedicled left internal thoracic artery graft (internal thoracic artery transected near its origin, thus supplied by retrograde flow from superior epigastric and musculophrenic arteries) might occasionally be the conduit of choice for those patients.

Heavily calcified ascending aorta significantly increased morbidity and lethality during open-heart surgery. Cannulation and clamping (partial or total) of severely atherosclerotic ascending aorta can easily cause damage and rupture of aortic wall, with consequential distal (often fatal) embolization with atheromatous debris (brain, myocardium). From June 1998. until June 2000, 11 of 2 136 (0.5%) patients who underwent coronary artery bypass grafting were with the severe atheromatous ascending aorta. The site of cannulation was in the aortic arch in three patients (aorta was occluded with Foley catheter in one case, and single clamp technique was used in the other two cases). The femoral artery was the cannulation site in other five cases. Profound hypothermia, ventricular fibrillation, and circulatory arrest, with no cross-clamping or cardioplegia, were used in three patients. Two patients were operated on with extracorporeal circulation, one in normothermia, on the beating heart, the other in moderate hypothermia, on fibrillating heart. In three patients myocardial revascularization was performed on the beating heart, in normothermia, without extracorporeal circulation. Postoperative course was uneventful in all 11 patients. Neither atheroembolism in the peripheral organs, nor atheroembolism of the extramities occurred. The proposed surgical approaches have the potential to reduce the prevalence of stroke and systemic embolization associated with coronary artery bypass grafting in patients with heavily calcified ascending aorta. This result was achieved due to the applied modifications of standard cardiosurgical technique.

Coronary artery bypass surgery in patient with bad left ventricular function is a challenge for surgical time. Specially important is monitoring of haemodynamics. We performed this open, prospective, randomized study with the aim to assess haemodynamics and oxygen profile monitoring. 34 pts for coronary surgery (EF < 40%) were divided in two groups. Group A, 17 pts. Received glucose-insulin-potassium (GIK) solution. Group B, 127 pts. Received Ringer solution. Haemodynamic and oxygen metabolism parameters were measured in four time points. I after the induction in anesthesia; II after the operation; III 6 hours post op.; IV 24 hour post op. Data are expressed as mean +/- SD, Anova for repeated measures followed by Newman-Keuls testing were used. In both groups were evident deterioration of cardiac function during first 6 h as well as VO2 and DO2, more prominent in Group B. Significant recovery and improvement of cardiac function were evident in Group A after 24 h. CI during the time in Group A improves significantly (2.14 +/- 0.36 v. 3.05 +/- 0.55; p = 0.0002) and difference during the time between groups was p = 0.005. LVSWI improved significantly during the time him Group A (AIII vs. AIV) p = 0.007. Simultaneously. VO2 improves significantly in Group A (103 +/- 21 vs. 164 +/- 30, p = 0.00001) while difference between groups in DO was p = 0.037. Importance of oxygen metabolism monitoring for both, left ventricular function and haemodynamics assessment was evident in our study.

Cardiac surgeons are treating an increasing number of patients after different sorts of complications occurring during various percutaneous procedures. Wire entrapment has been described in the literature and numerous maneuvers have been developed to solve this complication. If they fail, surgical management is absolutely indicated. In such cases the operation can be very demanding. After hardware removal the artery quality is usually unsatisfactory and endarterectomy with adjacent revascularization is mandatory. We report a case in which we used a termino-terminal interposition of the greater saphenous vein to restore a disintegrated part of the coronary artery.

Quadricuspid aortic valve is rare congenital anomaly. There are only 197 cases published in literature so far. That includes clinical and autopsy reports. This congenital anomaly occurs more often in pulmonary valve but function stays normal in 10 of 11es. On the other side, in aortic position valve is malfunctioning in 50% of cases. Valve regurgitation is more likely to occur than stenosis In this kind of malformation, valves are prone to early dysfunction and endocarditis due to different valve architecture and unequal distribution of mechanical stress along valve cusps. Aortic valve replacement is indicated in younger population of these patients. This is a case report of rare congenital anomaly of big blood vessels - aortic valve with four cusps. This anomaly produced significant aortic regurgitation so this patient was indicated for aortic valve replacement.

Adequate open exposure of the mitral valve is necessary to accomplish reconstruction or replacement of the diseased mitral valve apparatus. The technique employed by most cardiac surgeons for mitral valve access involves median sternotomy and vertical left atriotomy posterior to the interatrial sulcus. However, certain conditions can sometimes make this approach very difficult. Different approaches are discussed with particular emphasis on our case in which the transaortic double valve replacement have been performed.

Background Central (ScVO2) and mixed venous oxygen saturation (SvO2) and blood lactate are useful measurement tools for evaluating the degree of hypoperfusion in patients with different disease processes. The aim was to study incidence of both low as well as high ScvO2 and assessed their relationship to markers of tissue hypoxia, course and outcome in patients undergoing elective cardiac surgery.

We read with great interest the article by Chalmers et al. [1] regarding external validation of the EuroSCORE II performances. Since the EuroSCORE (European System for Cardiac Operative Risk Evaluation) was introduced in daily cardiac surgical practice [2], it has been used as a measure of operative risk of adult cardiac surgery patients in more than 1300 formal citations in the medical literature [3]. Although both the additive and the logistic both the additive and the logistic version of the EuroSCORE have remained very good discriminatory power, suspicions were raised that the model may now be inappropriately calibrated for current cardiac surgery [3]. Therefore, the old EuroSCORE was renewed into EuroSCORE II (database of 22 381 consecutive patients undergoing adult cardiac surgery in 154 hospitals in 43 countries over a 3 month period in 2010) in order to optimize its discriminatory power and especially its calibration [3]. Although the Hosmer–Lemeshow test was used in 95% of published manuscripts to test the calibration of the old EuroSCORE [4], the calibration of the EuroSCORE II was assessed using the observed/expected (O/E) ratio of mortality. Ideally, this ratio equals one (the observed mortality equals expected mortality, thus the predictive model is perfectly calibrated). A value above one means that the model underestimates mortality, whereas a value below one means that model overestimates mortality. If the 95% confidence interval (CI) of the O/E ratio excludes the value 1.0, it may be considered statistically significant [4]. Chalmers et al. [1] used Hosmer–Lemeshow statistics to validate the calibration ability of the EuroSCORE II (a single-institution experience; 5576 patients, including coronary surgery, valve surgery, mixed cases, aortic surgery and miscellaneous cases). The Hosmer–Lemeshow test confirmed good calibration of the EuroSCORE II model for all subgroups of cardiac surgery patients (P-values of 0.052–0.99), while overall calibration (all 5576 patients) was poor (P < 0.001). The calculated O/E ratio (using the data presented in Table 1 of Chalmers et al. [1]) and its 95% CI confirmed good calibration for all subgroups, except for miscellaneous cases (the model underestimated mortality). Observed mortality for all patients was 2.2%, and predicted mortality (EuroSCORE II) was 2.0% (112 patients). The O/E ratio confirmed good calibration. This would be a nice argument to support the opponents of Hosmer–Lemeshow statistics, were these data not misleading. In fact, all the data of categorical variables showed in the second column (all patients) of Table 1 of Chalmers et al. [1] were miscalculated (i.e. hypercholesterolaemia, 3866 of 5576, as 84.3% instead of 69.3%; urgent operation, 1295 of 5576 as 28.3%, instead of 23.2% etc.). In-hospital mortality has also been presented incorrectly. Neither is 101 of 5576 patients 2.2% (it is 1.8%), nor is the total number of all patients who died 101 (the correct overall number of patients who died is 191; then corrected mortality appears to be 3.43%). That leads us to the conclusion that the O/E ratio (191/112) is 1.71 (95% CI 1.47–1.95), thus not including the value of 1.0. Therefore, overall poor calibration has been confirmed with the O/E ratio of mortality, as well as with Hosmer– Lemeshow statistics.

The incidence of postcardiotomy myocardial failure (PMF) requiring mechanical circulatory support beyond IABP is reported to be 0.2% to 1.2%. From Dec. 1989 through Dec. 1995, 18 patients (0.3% of the total pump cases) were supported with roller pump type of LVAD. Assisted flow ranged from 3.5 up to 5 L/min with average support time of 35.5 hours. Six (33.3%) patients (pts) died while on LVAD. The causes of additional seven deaths (pts weaned of LVAD) were: myocardial failure (4), stroke (2) and intractable bleeding during removal of the LVAD (1). Overall, five patients (27.8 %) were successfully discharged from the hospital. Two out of five long-term survivors died later, 6 months and 4 years postoperatively, both of cardiac causes. The actuarial survival rate of long-term survivors was 60% at 7 years, all of them being in NYHA functional class II. These results have proved efficiency of roller pump driven LVAD for short-term circulatory support in pts with PMF. Results are comparable to so far published data on postcardiotomy support with the same, as well as other types of more versatile and costly devices.

We read with great interest the article by Nashef et al .[ 1] regarding the construction and validation of the EuroSCORE II risk model. This manuscript is an outstanding contribution in the creation of a risk stratification model that is robust enough for use in cardiac surgery worldwide. However, we would like to know which statistical procedure should be used to determine calibration of the EuroSCORE II? The Hosmer–Lemeshow goodness-of-fit test has been the most popular test to validate calibration [2, 3], measuring the differences between expected and observed outcomes (mortality) over deciles (test results are acceptable with cohort divided in at least terciles) of risk. A well-calibrated model gives a corresponding P value >0.05. Recently, it has been claimed that a nonsignificant Hosmer–Lemeshow test meant that there was no evidence of bad calibration, but that this result did not mean that there was good calibration [4]. In our opinion, statistical results are either significant or nonsignificant, black or white; there are no grey results in statistics. However, if that is true, how has it come to pass that we needed more than 10 years (during which Hosmer–Lemeshow statistics was used in more than 95% of manuscripts to test the calibration of additive and logistic EuroSCORE in cardiac surgery) to find out that Hosmer– Lemeshow test is no longer valid to determine calibration, and that it should be replaced with the risk-adjusted mortality ratio, [RAMR = observed/predicted (expected) – O/E mortality], as it is now suggested by Nashef et al [1]. An O/E ratio of 1.0 means that the score predicts mortality perfectly. An O/E ratio > 1.0 means that the model underpredicts mortality [in EuroSCORE II, for a validation data set of 5553 patients, the O/E ratio was 1.058 (4.18%/3.95%)], while an O/E ratio < 1.0 means that the model overpredicts mortality. However, how are we going to check the statistical significance of the RAMR value? Conceptually, if the observed number of deaths is equal to the expected number of deaths (as predicted by the scoring system), the RAMR would have a value of 1.0. Thus, the statistical test for the significance of the RAMR is whether it is different from 1.0. To gauge the statistical significance of the RAMR, we must first calculate the 95% confidence interval for the RAMR. If the 95% confidence interval excludes the value ‘1.0’, it may be considered statistically significant (no matter whether it overpredicts or underpredicts mortality). On the contrary, Bhatti et al .[ 5] suggested χ 2 statistics

The established superiority of the internal thoracic artery as a coronary arterial conduit has led to its mandatory use in coronary artery bypass grafting surgery. Therefore, the damage of the internal thoracic artery during harvesting is an abysmal complication, after which the conduit is usually discarded. An alternative approach is presented here, which has allowed us to use the distal two thirds of the proximally damaged left internal thoracic artery as an in situ (with retrograde blood supply from superior epigastric and musculophrenic arteries), reversed arterial conduit to revascularize the left anterior descending coronary artery.