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

BACKGROUND: Compared 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.

OBJECTIVES: The 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.

METHODS: This 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.

RESULTS: Persistent 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.

CONCLUSION: This 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.