Transcatheter aortic valve replacement (TAVR) or implantation (TAVI) demonstrably changed the treatment of high-risk patients with severe aortic stenosis, particularly those at high risk for surgical replacement of the aortic valve. However, greater acceptance of TAVR also raised concerns of complications, particularly increased risks for stroke or neurological and cognitive impairments from embolic events.
The entry of embolic protection devices (EPD) into the European (EU) market, with designs that deflect or collect potentially damaging micro-debris associated with TAVR, presents an evolving risk-reduction safety strategy to manage patients, who usually are elderly, with frail health or existing comorbidities.
This paper explores the potential for such EPDs as well as factors IQVIA MedTech believes sponsors should consider when developing or using EPDs in clinical trials.
Since the adoption of TAVR, stroke rates among patients appear to have declined due to enhanced devices, surgical expertise and patient selection. However, measures vary by stroke classification – major, minor, transient – and whether assessed during the hospital procedure or at a later date. Below are several studies frequently used as indicators of TAVRrelated stroke risk.
One of the most recent TAVR stroke evaluations is an April 2016 meta-analysis of eight studies and five registries. This review reported that study-stroke rates 30 days after TAVR ranged from 4.9 to 0.0 percent – and not significantly different from SAVR rates within each study, which varied from 6.2 to 0.5 percent. Similarly, the five registries reported 30-day rates of 2.5 to 4.1 percent and one-year rates of 4.1 to 4.5 percent. The registries included those in France, Germany and the United Kingdom, as well as that of the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry (STS/ACC).
Notably, STS/ACC data, published in 2013, often is cited on its own because it represents the largest singlesource evaluation of stroke in TAVR patients: 7,710 from the United States. This assessment examined major strokes both during the procedural hospital stay, 2.0 percent, and 30 days after, 2.8 percent.
One of the longest follow-up of stroke rates stems from the five-year data from The Placement of Aortic Transcatheter Valves (PARTNER) study, a randomized trial of TAVR vs. SAVR. The stroke rate at 30-days for TAVR was 3.8 percent, increasing to 5.1 percent at one year and 10.4 percent at five years. Notably, only the one-year rate significantly differed from SAVR.
Other studies have shown increased risk of stroke over time after TAVR. The U.S. CoreValve High Risk Study reported 30-day rates for any strokes at 4.9 percent and major strokes, 3.9 percent. At one year, the rates increased to 8.8 and 5.8 percent, respectively. The study did not find an increased risk of stroke from TAVR compared to SAVR.