Cardiovascular Function during First 24 Hours after Off-Pump and On-Pump CABG—A Prospective Observational Comparative Study

Purpose: Myocardial revascularization by coronary artery bypass grafting (CABG) in ischemic heart disease patients has direct impact on hemodynamic parameters in the immediate post-operative period. The peri-operative cardiovascular functioning is an important determinant for outcome of surgery. In On-Pump CABG (ONCAB), the cardiopulmonary bypass has a negative effect on myocardium. Off-Pump CABG (OPCAB) avoids the effect of CPB but complete revascularization with difficult positioning of heart is technically demanding. This study is aimed to compare the cardiovascular functioning in the immediate post-operative period after OPCAB and ONCAB. Methods: Total 106 patients were operated for CABG from January 2015 to June 2016, of which 75 patients were operated for OPCAB and 31 patients were operated for ONCAB. For the comparison, hemodynamic parameters were measured during anesthesia before surgery, postoperatively after 1 and 4 hours (h) in the ICU, and in the morning after surgery, approximately after 20 h. Results: The time-dependent rise of hemodynamic parameters like Cardiac Output (CO), Cardiac Index (CI), Stroke volume (SV) and Left Ventricular Stroke Work Index (LVSWI) in the immediate post-operative hours (1 h and 4 h) are more predominant in OPCAB group than ONCAB group although the difference is eliminated mostly at 20 h. The better peripheral vasodilation after OPCAB causes immediate fall of Systemic Vascular Resistance Index (SVRI) after OPCAB. Conclusion: Better cardiovascular functioning immediately after OPCAB than ONCAB may be important for better hemodynamic stability. The difference is however eliminated after 24 hours indicating little significance in long term outcome.

Level of Cardiac Biomarkers in Immediate Post-Operative Period after Off-Pump CABG and Its Comparison with On-Pump CABG: A Prospective Analytical Study

Background: Coronary artery bypass grafting (CABG) is an important modality of treatment for ischemic heart disease. Both off-pump and on-pump CABG have direct effect on the level cardiac biomarkers in the perioperative period. The use of cardiopulmonary bypass (CPB) and aortic cross-clamping may cause additive myocardial damage leading to further elevation of blood markers. The present study is aimed at measuring and comparing the cardiac biomarker levels in immediate post-operative period after on-pump CABG (ONCAB) and off-pump CABG (OPCAB). Methods: All the patients who underwent CABG from January 2015 to June 2016 on elective or emergency basis at Nilratan Sircar Medical College & Hospital have been included in the study. Total 106 patients were operated for CABG of which 75 patients were operated for OPCAB and 31 patients were operated for ONCAB. For the comparison of data the blood markers Troponin-T (Trop-T) and Creatine Kinase-MB (CK-MB) are measured during anesthesia before surgery, post-operatively after 1 hour, post-operatively after 4 hours and post-operatively after 20 hours. All recorded data are analyzed using standard statistical methods. Results: We found the markers are elevated immediately after surgery and gradually come down within 24 hours after surgery in both OPCAB and ONCAB groups. The elevation is more after ONCAB than OPCAB group in immediate post-operative period but the difference is not significant after 20 hours of surgery. Conclusion: Elevated levels of cardiac biomarkers in the immediate post-operative period indicate myocardial damage during surgery, especially after ONCAB in comparison to OPCAB. This may attribute to the better hemodynamic stability in the immediate post-operative period after OPCAB than ONCAB assuming comparable and adequate revascularization in patients of both groups. The avoidance of CPB and cross-clamp may explain better myocardial functioning immediately after OPCAB. But after 20 hours, the level of cardiac markers is comparable in both groups indicating little difference in post-operative recovery and long-term prognosis.