New data indicate that patients who develop bundle branch block (BBB) and/or require a new permanent pacemaker after undergoing transcatheter aortic valve implantation (TAVI) have a significantly increased risk of late all-cause mortality. They also have a higher risk of heart failure hospitalisation. These findings suggest that contrary to some previous studies, BBB and/or pacemaker implantation after TAVI is not a harmless complication.
Troels H Jørgensen (Rigshospitalet, The Heart Centre, Copenhagen, Denmark) and others write in the JACC: Cardiovascular Interventions that the clinical impact of conduction abnormalities, such as BBB, “remains controversial”. They explain: “New-onset left BBB and post-procedural permanent pacemaker implantation have shown inconsistent effects of mortality and heart failure after TAVI.” Therefore, the aim of the present study was to further review the incidence and outcomes of the TAVI-induced BBB and/or permanent pacemaker implantation.
Reviewing data from their centre (Rigshospitalet, Copenhagen, Denmark), Jørgensen et al identified 816 patients who underwent TAVI between August 2007 and September 2017. Of these, 437 did not develop conduction abnormalities, 247 developed new BBB, and 132 required a permanent pacemaker implantation. “More patients with new BBB (19) received permanent pacemakers later than 30 days after TAVI compared with patients with no conduction abnormalities (15),” the authors observe.
Five-year all-cause mortality was significantly higher for patients who developed BBB and/or required a pacemaker: 48.4% and 46.7% vs. 32.8% for those without conduction abnormalities (p=0.0003). While the hazard rates of early (<1 year) and late (≥1 year) mortality were both significantly higher for patients with BBB compared with those without conduction abnormalities, only late mortality was significantly higher for patients with a permanent pacemaker (vs. those without conduction abnormalities). Jørgensen et al comment that, potentially, patients with a permanent pacemaker were protected from the risk of sudden cardiac death that has been in patients with left BBB.
Furthermore, the hazard rate of first heart failure hospitalisation was higher for both patients with BBB and those who had a pacemaker vs. those who did not have conduction abnormalities but no pacemaker. The mean number of recurrent heart failure hospitalisations up to five years after TAVI was also higher for these groups. However, when patients with no heart failure admissions were excluded from the analysis, there were no significant differences between groups in the mean number of recurrent heart failure hospitalisations.
Left ventricular ejection fraction (LVEF) was significantly reduced in both patients with BBB and those with a pacemaker. The authors note that this finding and the increased risk for heart failure hospitalisation that was seen in these groups “could be a co-factor in the increased risk of mortality observed in these patients compared with those with no conduction abnormalities”. “Thus, neither new BBB nor permanent pacemaker implantation appears benign in the long-term, indicating that prevention is the best long-term treatment of TAVI-induced conduction abnormalities and that these patients may benefit from closer follow-up,” they add.
Speaking to Cardiovascular News about the data, Jørgensen comments that their results would “not necessarily” be any different had they only reviewed new-generation TAVI devices (given the study reviewed data from 2007, first-generation devices would have been included). He says: “Considering the similar rates of both new-onset BBB and need for permanent pacemaker with the newer generation transcatheter heart valves as compared with the early iterations, it is not probable that the risk of new-onset conduction abnormalities would have been different if only including newer generation valves. Further, the pathophysiology behind new-onset conduction abnormality leading to late death would be expected to be the same regardless of type of implanted valve.” In terms of prevent conduction abnormalities (and potential pacemaker implantation), Jørgensen states: “As with the risk of paravalvular leakage that has been reduced over the past decade, the risk of new-onset conduction abnormalities might be reduced by focused design features of future transcatheter heart valve generations.”