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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/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. 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.

Abstract.: Resveratrol, a stilbene polyphenol found in grapes and red wine, produces vasorelaxation in both endothelium-dependent and endothelium-independent manners. The mechanisms by which resveratrol causes vasodilatation are uncertain. The aim of this study was to investigate the mechanism(s) of endothelium-independent resveratrol-induced vasorelaxation in human internal mammary artery (HIMA) obtained from male patients undergoing coronary artery bypass surgery and to clarify the contribution of different K+ channel subtypes in resveratrol action in this blood vessel. HIMA rings without endothelium were precontracted with phenylephrine. Resveratrol induced a concentration-dependent relaxation of the HIMA. A highly selective blocker of ATP-sensitive K+ channels, glibenclamide, as well as nonselective blockers of Ca2+-sensitive K+ channels, tetraethylammonium and charybdotoxin, did not block resveratrol-induced relaxation of HIMA rings. 4-Aminopyridine (4-AP), non selective blocker of voltage-gated K+ (KV) channels, and margatoxin that inhibits KV1.2, KV1.3, and KV1.6 channels abolished relaxation of HIMA rings induced by resveratrol. In conclusion, we have shown that resveratrol potently relaxed HIMA rings with denuded endothelium. It seems that 4-AP- and margatoxin-sensitive K+ channels located in smooth muscle of HIMA mediated this relaxation. Keywords:: resveratrol, vasorelaxation, human internal mammary artery, K+ channel

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.

Abstract Background Prognostic value of concomitant aprtic regurgitation (AR) in patients operated for severe aortic stenosis (AS) is not clarified. The aim of this study was to prospectively examine the impact of presence and severity of concomitant AR in patients operated for severe AS on long-term functional capacity, left ventricular (LV) function and mortality. Methods Study group consisted of 110 consecutive patients operated due to severe AS. The patients were divided into AS group (56 patients with AS without AR or with mild AR) and AS+AR group (54 patients with AS and moderate, severe or very severe AR). Follow-up included clinical examination, six minutes walk test (6MWT) and echocardiography 12 and 104 months after AVR. Results Patients in AS group had lower LV volume indices throughout the study than patients in AS+AR group. Patients in AS group did not have postoperative decrease in LV volume indices, whereas patients in AS+AR group experienced decrease in LV volume indices at 12 and 104 months. Unlike LV volume indices, LV mass index was significantly lower in both groups after 12 and 104 months as compared to preoperative values. Mean LVEF remained unchanged in both groups throughout the study. NYHA class was improved in both groups at 12 months, but at 104 months remained improved only in patients with AS. On the other hand, distance covered during 6MWT was longer at 104 months as compared to 12 months only in AS+AR group (p = 0,013), but patients in AS group walked longer at 12 months than patients in AS+AR group (p = 0,002). There were 30 deaths during study period, of which 13 (10 due to cardiovascular causes) in AS group and 17 (12 due to cardiovascular causes) in AS+AR group. Kaplan-Meier analysis showed that the survival probability was similar between the groups. Multivariate analysis identified diabetes mellitus (beta 1.78, p = 0.038) and LVEF < 45% (beta 1.92, p = 0.049) as the only independent predictor of long-term mortality. Conclusion Our data indicate that the preoperative presence and severity of concomitant AR has no influence on long-term postoperative outcome, LV function and functional capacity in patients undergoing AVR for severe AS.

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., (Copyright © 2021 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.)