Frequency and prognosis of new bundle branch block induced by surgical aortic valve replacement

Recently, transcatheter aortic valve implantation has been introduced, but one of its complications is left bundle branch block (LBBB), a conduction disturbance that has been associated with increased mortality. We investigated the incidence and fate of both right bundle branch block (RBBB) and LBBB after aortic valve replacement (AVR) using a retrospective analysis. We also studied the predictive value of both disorders for all-cause mortality.

All patients who underwent AVR, with or without concomitant coronary artery bypass grafting surgery, between 2002 and 2010 in our centre were included. All-cause mortality was compared between patients who did and those who did not develop persistent new bundle branch block (BBB) within 7 days postoperatively. Patients were not eligible if one of their electrocardiogram (ECG) recordings prior to AVR showed a BBB or pacemaker activity. A postoperative period of 3-12 months was used to collect follow-up ECGs.

Of the 2279 AVR patients, 2033 patients were eligible for analysis. After excluding patients lacking baseline or follow-up ECG (n = 269), 1764 patients remained for analysis. Early LBBB and RBBB occurred in 71 (4.0%) and 92 (5.2%) patients, respectively. At follow-up, LBBB was persistent in 29 patients (1.6%) and RBBB in 74 patients (4.2%). During a median follow-up of 4.5 (2.4-6.5) years, the mortality rate was 16.3% (n = 271) in patients without BBB, 24.1% (n = 7) in patients with persistent LBBB and 18.9% (n = 14) in patients with persistent RBBB (log-rank P = 0.49). Though, in univariate analysis, the hazard ratio for mortality was 1.54 and 1.10 for LBBB and RBBB, respectively, the small numbers precluded identifying AVR-induced LBBB and RBBB as a predictor of mortality.

In the current practice of AVR, persistent postoperative LBBB and RBBB occur infrequently (∼ 5% of cases), a percentage less than half of that in current transcatheter aortic valve implantation procedures. Given the adverse effects of LBBB, the lower prevalence of procedure-induced LBBB in AVR should be taken into account while deciding which valve replacement procedure is chosen for a patient.