Clinical impact of a new left bundle branch block following TAVI implantation: 1-year results of the TAVIK cohort.

backgroundCompared with surgical aortic valve replacement, transcatheter aortic valve implantation (TAVI) is associated with a higher risk of developing a new conduction disorder that necessitates permanent pacemaker implantation (PM). The most frequently observed conduction disorder is left bundle branch block (LBBB), which impairs left ventricular function.

objectivesThe primary objective of this study was to assess the incidence and prognostic significance of persistent new-onset LBBB following TAVI. Factors predictive of persistent new-onset LBBB were also explored.

methodsThis study included a total of 793 patients who underwent TAVI between May 2008 and April 2012. Patients were divided into two groups: those with persistent new-onset LBBB and those without persistent new-onset LBBB. Follow-up was conducted within 1-year of TAVI.

resultsPersistent new-onset LBBB was observed in 31.1 % (n = 197) out of 634 eligible patients. At 30 days and 1-year post-TAVI, the all-cause mortality rate was higher in patients with persistent new-onset LBBB (6.1 %, n = 12 and 20.8 %, n = 41, respectively) than in patients without new-onset LBBB (3.3 %, n = 10 and 13.0 %, n = 57, respectively; p = 0.014 and p = 0.010 for the two time points). Multivariate regression analyses revealed, that persistent new-onset LBBB was an independent predictor of all-cause mortality at 1 year (HR 1.84, 95 %CI 1.35-2.02). PM implantation was observed slightly more frequently in patients with persistent new-onset LBBB (14.2 %) than in those without (9.4 %; HR 1.60, 95 %CI 0.96-2.67). Risk factors for pacemaker (PM) were baseline RBBB (HR 6.23, 95 %CI 3.76-10.33), chronic atrial fibrillation (HR 1.75, 95 %CI 1.10-2.56) and the Medtronic CoreValve implantation (HR 2.40, 95 %CI 1.55-3.75). At 1-year follow-up, the mean survival of patients with PM (81.2 %) was slightly lower, but not significantly different from that of patients without PM (85.0 %; p = 0.377). Upon multivariable logistic binary regression analysis Medtronic CoreValve was associated with an increase rate of persistent new-onset LBBB (HR 2.52, 95 %CI 1.67-3.80) and PM implantation. Mortality during 1 year of follow-up, however, was neither increased in the total population (p = 0.232), nor in a subgroup of those with LBBB in a comparison of Medtronic CoreValve and Edwards SAPIEN.

conclusionThis study demonstrated that persistent new-onset LBBB was associated with increased mortality in patients undergoing TAVI. Compared with the Edwards SAPIEN valve, implantation of the Medtronic CoreValve resulted in a higher rate of both persistent new-onset LBBB and PM but not death.