Pre-operative anaemia-does it influence post-operative outcomes after isolated coronary artery bypass grafting?

Introduction: Preoperative anaemia is prevalent in a number of patients undergoing coronary artery bypass grafting. Studies provide conflicting results due to several reasons including variation in the threshold of haematocrit used to define anaemia. We aimed to assess the independent effect of preoperative anaemia on outcomes in patients undergoing off pump coronary artery bypass grafting (OPCAB). Methods: In this retrospective study, patients with a hemoglobin level less than 11g/dl (haematocrit <33%) were considered to have moderate-to-severe anaemia as per the recommendations of the World Health Organization. Association between haematocrit <33% and mortality as well as adverse post-operative outcomes was assessed. Multivariable logistic regression (MLR) was carried out to assess the independent effect of haematocrit<33% on 30-day mortality and other outcomes. Results: The study included 4957 consecutive patients undergoing isolated OPCAB surgery between 2015 and 2020. Out of 4957, 635 (12.8%) had haematocrit <33% and 4322 (81.2%) had haematocrit ≥33%. Patients with haematocrit < 33% had a 30-day mortality of 13 (2%) compared to 38 (0.9%) in patients without anaemia and had a greater requirement for blood transfusion (p<0.0001). It was also associated with an increased incidence of renal failure (p<0.0001), tracheostomy (p=.0.012) and risk of re-intubation (p=0.006). On multiple linear regression (MLR), haematocrit < 33% was not an independent predictor of 30-day mortality odds ratio (OR) 1.47, 95% confidence interval (CI) 0.745-2.917; p=0.26. It was however an important independent risk factor for blood transfusion (OR 1.80, 95% CI 1.29-2.50, p<0.001) and renal failure (OR 3.06, 95% CI 1.338-7.012, p=0.008). The receiver operating characteristic (ROC)-area under the curve (AUC) was 0.63 suggesting moderate discriminatory value of haematocrit < 33% for 30-day mortality. Conclusion: Haematocrit < 33% is an important risk factor for adverse outcomes following isolated, primary, elective OPCAB. Supplementary Information: The online version contains supplementary material available at 10.1007/s12055-024-01746-1.

Impact of distension pressure on saphenous vein endothelial injury in coronary artery bypass grafting.

Introduction: Long saphenous vein grafts (LSVGs) are pivotal conduits in coronary artery bypass grafting (CABG), yet concerns persist regarding early failure and long-term patency. Endothelial damage, a potent initiator of graft failure, necessitates exploration of factors contributing to endothelial injury during LSVG preparation. Methods: A prospective, single-center study was conducted, assessing the impact of unregulated distension pressure on LSVG endothelium during CABG. Histological and CD31 (cluster of differentiation 31) immunohistochemical analyses were performed on 21 paired vein samples, categorized into non-distended (group A) and distended (group B) groups. Pressure recordings were obtained using different syringe sizes during vein distension. Results: Histological examination revealed a significantly higher percentage of endothelial cell loss in distended veins (31.95% ± 31.31) compared to non-distended veins (11.67% ± 28.65) (p = 0.034). CD31 immunohistochemistry corroborated greater endothelial cell loss in distended veins (p = 0.001). The pressure recordings with a 20-cc syringe, as opposed to using a 10-cc syringe, were considerably lower (44.5 mmHg vs. 92.75 mmHg) emphasizing the inverse relationship between syringe size and pressure generated. In our study, pre-existing endothelial injury was observed in one-third of diabetic patients (36%), with all instances of such injury exclusively identified in individuals with diabetes. Conclusion: Unregulated distension pressure during LSVG preparation is associated with greater endothelial damage, as evidenced by histological and immunohistochemical analyses. The inverse relationship between syringe size and pressure underscores the importance of controlled distension.

Cardiac magnetic resonance imaging for myocardial viability assessment: Optimizing surgical revascularization in ischemic heart disease.

BACKGROUND: Patients with poor ejection fraction undergoing coronary artery bypass grafting carry higher operative risk and have poor long-term survival. Cardiac magnetic resonance is a useful modality to assess viability which can identify patients likely to benefit most from revascularization. In this study, we aimed to assess the outcome in patients selected for surgical revascularization by cardiac magnetic resonance imaging and identify predictors associated with poor outcomes. METHODS: The study included patients with severely impaired left ventricular function but with at least six viable segments. Patients requiring emergency surgery, undergoing combined procedures, or where cardiopulmonary bypass was required were excluded. Cardiac magnetic resonance was carried out both preoperatively and at six months postoperatively by the same radiologist in all cases. Late gadolinium enhancement was used for the evaluation of myocardial viability. RESULTS: Amongst a total of 493 segments studied, there were 89 (18.1%) non-viable, 117 (23.7%) hibernating and 287 (58.2%) viable segments. At six months, the number of non-viable segments changed from 89 (18.1%) to 97 (19.7%), with an increase in viable segments from 287 (58.2%) to 374 (75.8%) and a corresponding reduction of hibernating segments from 117 (23.7%) to 22 (4.5%). There was improvement in ejection fraction from 28 ± 5.54 to 37 ± 5.86 (p < 0.0001) in the entire cohort at six months. Overall mortality was 1 (3.2%). Preoperative left ventricular end-systolic volume had the strongest negative correlation with post-operative ejection fraction. CONCLUSION: Cardiac magnetic resonance aided revascularization is associated with low mortality. Preoperative left ventricular end-systolic volume is an important determinant of postoperative ejection fraction.

Incidence, predictors, and outcome for post-operative atrial fibrillation in Indian patients undergoing off-pump coronary artery bypass grafting-a prospective observational study.

Purpose: Indian patients who undergo surgical revascularization are relatively younger than their Western counterparts and are predominantly revascularized using off-pump coronary artery bypass grafting (OPCAB) technique. They may therefore be at a reduced risk of developing post-operative atrial fibrillation (POAF). The aim of this study was to assess the incidence of POAF, measure its impact on outcomes, and identify the predictors for POAF in the Indian patients undergoing OPCAB. Besides, the ability of European System for Cardiac Operative Risk Evaluation (EuroSCORE) and Society of Thoracic Surgeons (STS) scores in predicting POAF was also assessed. Methods: In this prospective observational study, all patients undergoing isolated OPCAB in a single institution over a 12-month period were included. Patients undergoing re-operative surgery, emergency procedure, concomitant surgery, or those with history of previously diagnosed or treated atrial fibrillation were excluded. Logistic regression was performed to identify the predictors of POAF. The receiver operating characteristic (ROC) curve was used to determine the ability of EuroSCORE and STS scores to assess risk of developing POAF. Results: We recruited 1108 patients in the study of which 88 (7.94%) patients developed POAF. Age (OR = 1.082, p < 0.001, 95%CI: 1.050-1.114), unstable angina (OR = 16.32, p = 0.036, 95%CI: 1.2-221.4), presence of diabetes mellitus (OR 1.781, p = 0.025, 95%CI: 1.074-2.955), left atrial size (OR 2.506, p = 0.001, 95%CI: 1.478-4.251), and presence of chronic renal failure (OR 8.7, p = 0.001, 95%CI: 2.4-31.53) were significant predictors of POAF. Both the EuroSCORE (p = 0.035) and the STS score (p = 0.001) were significantly higher in patients developing POAF. The area under the ROC curve for the EuroSCORE II was 0.62 and for the STS score was 0.64 suggesting satisfactory and similar discriminatory power of both the scores to predict POAF in these patients. POAF was associated with significantly increased adverse outcomes like stroke and prolonged hospital stay. Conclusions: In our study, the incidence of POAF was much lower (7.94%) than that reported previously. POAF significantly increased adverse outcomes and length of hospital stay. Both EuroSCORE II and STS scores had similar discriminating power in predicting POAF.

Lactate levels: A reliable tool to predict mortality in acute type A aortic dissections?

Lactate levels are surrogate markers of malperfusion in patients presenting with type A aortic dissections. Lactate measurement is simple, easy to perform, universally available, and thus can be an important tool for predicting mortality. However, the discriminatory power varies between studies and no cut-off point has been defined that can determine outcomes in the most reliable fashion. The risk prediction based on lactate levels can be improved when combined with other clinical and laboratory prognostic factors. Further studies with a much larger sample size, need to be carried out using serial measurements at well-defined time points to try and identify a cut-off value. The addition of lactate values to existing risk prediction scores or developing a new score based on it should be the subject of future research.

Comparison of European System for Cardiac Operative Risk Evaluation (EuroSCORE) and the Society of Thoracic Surgeons(STS) score for risk prediction in Indian patients undergoing coronary artery bypass grafting.

BACKGROUND: For risk stratifying patients undergoing coronary artery bypass graft (CABG), the Society of Thoracic Surgeons (STS) risk score and the European System for Cardiac Operative Risk Evaluation (EuroSCORE) are currently used. However, the superiority of one over the other in the context of Indian patients has not been assessed. The aim of this study was to compare these 2 scoring systems in Indian patients undergoing CABG. METHODOLOGY: This was a retrospective analysis of prospectively collected data between January 2015 and September 2020 of all patients undergoing CABG. Observed mortality in the cohort was compared with the predicted mortality using the STS and the EuroSCORE II. Sensitivity and specificity were calculated for both the scores. Receiver operating characteristic (ROC) curves were constructed for both the STS and the EuroSCORE II and area under the ROC curve (AUC) was calculated. RESULTS: A total of 4895 patients were included in the study. The overall observed mortality in the entire cohort was 74 (1.5%). The EuroSCORE II-predicted mortality was 1.9 ± 2.5 whereas the STS score-predicted mortality was 1.2 ± 1.8. The observed to predicted mortality ratio for EuroSCORE was 0.79 and 1.25 for the STS score. The discriminative ability for operative mortality of the STS score was 0.72 (0.71 to 0.74) and 0.713 for the EuroSCORE, suggesting satisfactory discriminatory power. There was no difference between the STS score and the EuroSCORE in terms of discriminatory power (p = 0.58) and a difference in the AUC being 0.01. The discriminatory power of the EuroSCORE and the STS score was best in the high-risk category. CONCLUSIONS: Both the EuroSCORE and the STS scores had satisfactory and similar discriminatory power. However, in the Indian population, while the EuroSCORE II overestimated mortality, the STS score underestimated it to a similar degree of error.

Timing of coronary artery bypass grafting after acute myocardial infarction: does it influence outcomes?

INTRODUCTION: The optimal timing of coronary artery bypass grafting (CABG) operations in patients with recent acute myocardial infarction (AMI) remains unclear. AIM: To assess the influence of timing on post-operative outcomes in patients undergoing CABG following AMI. MATERIAL AND METHODS: In this retrospective analysis 12,224 consecutive patients undergoing CABG were included. 2477 (20.5%) patients had a history of AMI. Based on timing, patients were divided into 3 groups: those operated within 7 days of AMI; those operated after 7 days but within 1 month; and a third group operated after 1 month but within 3 months. The 3 groups were compared in terms of baseline, intra-operative, and post-operative morbidity and mortality. Multivariate analysis was carried out to assess the independent influence of timing of CABG on outcomes. RESULTS: There was no difference in terms of previous neurological events (p = 0.554), presence of carotid artery disease (p = 0.555), prevalence of hypertension (p = 0.119), diabetes (p = 0.144), hypothyroidism (p = 0.53), chronic obstructive pulmonary disease (p = 0.079), peripheral vascular disease (p = 0.771), and impaired left ventricular function (p = 0.072). On univariate analysis, mortality risk was highest between 1 week and 1 month (p = 0.003). Multivariate analysis showed that the closer the MI and CABG duration, the higher the mortality (co-efficient -0.517; p = 0.019; odds ratio = 0.596; 95% CI: 0.388-0.917). CONCLUSIONS: The duration between MI and CABG has a direct influence on outcomes after CABG. While it is clear that the longer the duration between MI and CABG, the lower the mortality risk, it is however difficult to decide on an exact cut-off time frame.

Surgical repair of total anomalous pulmonary venous connection: Lateral approach.

We describe the lateral approach to the surgical repair of a total anomalous pulmonary venous connection in this video tutorial. The goal of the operation is to create an unobstructed anastomosis between the pulmonary confluence and the left atrium, ligate the systemic venous connections, and close the atrial septal defect. After a median sternotomy and initial dissection of the structures surrounding the heart, cardiopulmonary bypass is initiated by aortobicaval cannulation. The patient is then cooled to attain mild hypothermia (30°C). The heart is arrested by a dose of antegrade cold cardioplegia. The right pleural cavity is opened widely. The heart is retracted and pushed into the right pleural cavity. The vertical vein is ligated near its connection with the innominate vein. An incision is made along the length of the confluence, stopping short of the individual pulmonary veins. The left atrial appendage is retracted, and the left atrium is opened in alignment with the opening in the confluence. The left atrium and the pulmonary confluence are anastomosed widely with 7-0 polypropylene suture material. The heart is put back into the mediastinum. Rewarming is started. The atrial septal defect is closed through the right atrium using a large untreated autologous pericardium patch. The patient is then weaned off cardiopulmonary bypass.