Unveiling the Hidden Threat: Delayed High-Grade Atrioventricular Block After TAVI

Transcatheter aortic valve implantation (TAVI) has revolutionised the treatment of aortic stenosis in elderly patients and those at high surgical risk. However, one significant complication that can occur post-TAVI is high-grade atrioventricular block (HGAVB), which often necessitates the implantation of a permanent pacemaker (PPM). While acute HGAVB, occurring during the procedure or within the first 48 hours, is well-documented, this research explores the less understood realm of delayed HGAVB. This condition typically manifests more than 48 hours after TAVI or following discharge and can lead to syncope and even sudden cardiac death. Under the supervision of Professor Ravinay Bhindi, Dr Karan Rao’s comprehensive review aims to estimate the incidence of delayed HGAVB and identify the limitations of current literature in this domain.

To achieve this objective, Dr Karan Rao conducted a systematic review by meticulously searching prominent online databases, including Medline, Cochrane, Web of Science, and Scopus. Dr Rao and his team specifically sought studies that defined their outcomes as “delayed” or “late” atrioventricular block following TAVI. To maintain the focus on the delayed form of HGAVB, they excluded patients with prior PPM or aortic valve surgery. Their initial search cast a wide net, yielding 775 relevant studies. After a rigorous screening process, they narrowed their selection down to 19 studies that met their criteria.

Their analysis encompassed data from 19 studies, involving a total of 14,898 patients. These patients had an average age of 81.7 years, with 46.3% being male. The mean Society of Thoracic Surgeons (STS) score, a common measure of surgical risk, was 5.6%. Notably, 31.3% of the patients had known atrial fibrillation, a common cardiac arrhythmia. In terms of the TAVI procedures themselves, the most frequently used access site was transfemoral (84.8%). Balloon-expandable valves were employed in 62.1% of cases, while self-expanding valves were used in 34.0%, and mechanically expanding valves in 3.9%.

One of the key findings of their review was the wide range in the reported incidence of delayed HGAVB, spanning from 1.7% to 14.6%. Notably, they observed significant methodological heterogeneity among the studies they included.

Dr Rao and his team found that delayed high-grade atrioventricular block is a prevalent and potentially serious complication associated with TAVI. It shares several risk factors with its acute counterpart, making it an issue of paramount concern. Given the growing trend towards early discharge following TAVI procedures, further prospective studies on delayed HGAVB are urgently warranted. These studies should aim to enhance the understanding of predisposing factors, incidence rates, timing of onset, and the clinical implications of this condition. By shedding light on the hidden risks and nuances of delayed HGAVB, healthcare providers can be better equipped to manage this complication and ensure the well-being of TAVI patients. As the field of cardiology continues to evolve, knowledge and research in this area will be crucial for enhancing patient care and outcomes.

To read the full version of Dr Karan Rao’s systematic review of delayed high-grade atrioventricular block after transcatheter aortic valve implantation click here.