Predictors of Outcomes After Coronary Artery Bypass Grafting: The Effect of Concomitant Mitral Repair

Abstract

Background Ischemic mitral regurgitation (IMR) or functional MR intensity with or without repair increases the risk of coronary artery bypass grafting (CABG), and if the contaminant is undertaken, it doubles the risk of the surgery. This study aimed to characterize patients with concomitant CABG and mitral valve repair (MVR) and assess the surgical and long-term outcomes. Methods We conducted a cohort study from 2014 to 2020 on 364 patients who underwent CABG. A total of 364 patients were enrolled and divided into two groups. Group I (n= 349) included patients with isolated CABG, and Group II included patients who underwent CABG with concomitant mitral valve repair (MVR) (n= 15). Results Regarding preoperative presentation, most patients were male: 289 (79.40%), hypertensive 306 (84.07%), diabetic 281 (77.20%), dyslipidemic 246 (67.58%), presenting with NYHA classes III-IV: 200 (54.95%), and upon angiography, found to have the three-vessel disease: 265 (73%). Regarding their age mean± SD and Log EuroSCORE median (Q1-Q3), they had a mean age of 60.94± 10.60 years and a median score of 1.87 (1.13-3.19). The most prevalent postoperative complications were low cardiac output 75 (20.66%), acute kidney injury (AKI) 63 (17.45%), respiratory complications 55 (15.32%), and atrial fibrillation (AF) 55 (15.15%). Regarding long-term outcomes, most patients reported class I NYHA 271 (83.13%) and an echocardiographic decrease in MR severity. Patients with a CABG + MVR were significantly younger (53.93± 15.02 vs. 61.24± 10.29 years; P= 0.009), had a lower ejection fraction (33.6 [25-50] vs. 50 [43-55] %; p= 0.032), and had a higher prevalence of LV dilation (32 [9.17%]). EuroSCORE was significantly higher in patients with mitral repair (3.59 [1.54-8.63] vs. 1.78 (1.13-3.11); P= 0.022). The mortality percentage was higher with MVR but did not attain statistical significance. Intraoperative CPB and ischemic durations were longer in the CABG + MVR group. Furthermore, neurological complications were higher in patients with mitral repair (4 (28.57%) vs. 30 (8.65%), P= 0.012). The study's follow-up duration median was 24 (9-36) months. The composite endpoint occurred more frequently in older patients (HR: 1.05 [95% CI: 1.02-1.09]; 0.001), patients with low ejection fraction (HR: 0.96 [95% CI: 0.93-0.99]; P= 0.006) and in patients with preoperative myocardial infarction (MI) (HR: 2.3 [95%: 1.14- 4.68]; P= 0.021). Conclusion Most IMR patients benefited from CABG and CABG + MVR, as evident by NYHA class and echocardiographic follow-up. CABG + MVR had a higher Log EuroSCORE risk with increased intraoperative cardiopulmonary bypass (CPB) and ischemic durations, which may have played a role in increasing the incidence of postoperative neurological complications. On follow-up, no differences were reported between the two groups. However, age, ejection fraction, and a history of preoperative MI were identified as factors affecting the composite endpoint.