DAPT during valve-in-valve TAVR may reduce stroke risk—more data still required
Treating patients with dual antiplatelet therapy (DAPT) after valve-in-valve transcatheter aortic valve replacement (TAVR) instead of single antiplatelet therapy (SAPT) may help reduce their risk of experiencing a stroke, according to new findings published in JACC: Cardiovascular Interventions.[1]
“Although the data indicate a beneficial effect of less intensive antithrombotic therapy, it remains uncertain whether these findings apply to patients undergoing TAVR for bioprosthetic valve disfunction (valve-in-valve), as no studies have been conducted on this specific population,” wrote corresponding author Francesco Saia, MD, PhD, a cardiologist with IRCCS University Hospital of Bologna, and colleagues. “These patients may be particularly prone to thrombosis: in vitro and computational models of valve-in-valve TAVR showed markedly reduced blood flow in aortic sinuses, neosinuses (i.e. spaces between the new valve and the degenerated bioprosthesis) and on the aortic side of the leaflets. Such low-flow conditions create a prothrombotic milieu through mechanisms involving both platelets and coagulation cascade. Furthermore, valve underexpansion with consequent ‘pinwheeling’ effect (i.e. twisting of the leaflet free edges due to tissue redundancy), is more frequent in this population and was identified as a predictor of subclinical leaflet thrombosis.”
To learn more, Saia et al. tracked data from 278 valve-in-valve TAVR patients treated from January 2008 to 2023 at one of 10 facilities. Patients with failed surgical and transcatheter heart valves were included.
While 59% of patients were treated with DAPT following valve-in-valve TAVR, the remaining 41% were treated with SAPT. The median DAPT duration was six months. When patients were treated with SAPT, 94.7% of them were given aspirin. When patients were treated with DAPT, meanwhile, 99.4% received clopidogrel in addition to aspirin.
The group was primarily focused on tracking major adverse cardiac and cerebrovascular events (MACCEs) and bleeding events after one year. A MACCE was defined as any cardiovascular mortality, stroke or myocardial infarction.
Tracking major adverse events after one year
The one-year MAACE rates were 5.6% for DAPT and 7.5% for SAPT. This was not seen as a significant difference. All-cause mortality, cardiovascular mortality and myocardial infarction rates were also comparable after one year. The stroke rate, however, was lower in patients treated with DAPT (0.6%) than those treated with SAPT (4.6%).
The authors did add that two of the SAPT-related strokes occurred on the day of the procedure. If excluding those two patients, the stroke rates are much closer (0.6% vs. 2.7%) for the two treatment options.
“Although the analysis suggests a lower stroke incidence in patients treated with DAPT, this finding should be interpreted with caution due to the limited number of events,” the authors wrote. “Given the observed event rate, a substantially larger population would be required to obtain optimal statistical power. Therefore, the observed association, although statistically significant, should be considered as hypothesis-generating.”
Other key outcomes
When it came to major bleeding events, on the other hand, there was no significant risk between the two groups after one year. Minor bleeding events, the authors added, were more frequent for DAPT patients than SAPT patients. This was an expected outcome among patients receiving both medications following treatment.
Another key finding from this study is the fact that SAPT patients were associated with an increase in mean transvalvular gradient on follow-up echocardiography results. This trend, which did not lead to a significant difference in clinically relevant valve degeneration, was not seen with DAPT patients.
Overall, perhaps the biggest takeaway from this study is that additional research is still necessary. DAPT was associated with a lower stroke rate, but excluding any strokes that occurred during the valve-in-valve TAVR procedures resulted in comparable stroke rates for the two therapy options.
“Further studies are needed to confirm our findings and to investigate a potential role of more intense antithrombotic treatment in this setting,” the authors concluded.
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Michael has more than 19 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.