Findings from a PARTNER 3 substudy presented at TCT 2019 suggest that despite the high incidence of hypo-attenuated leaflet thickening (HALT) and reduced leaflet motion in transcatheter and surgical aortic bioprosthetic valves, "lack of a clear association with serious clinical events such as death, MI and stroke does not justify the routine prophylactic use of anticoagulation in all patients."

The blinded substudy by Raj R. Makkar, MD, FACC, and colleagues analyzed serial CT scans in 408 low-risk patients at 30 days and one year post-TAVR with SAPIEN 3 or surgery. The goals: to assess differences in transcatheter and surgical bioprosthetic aortic valves; natural history of HALT and reduced leaflet motion in the absence of anticoagulation; and impact on valve hemodynamics and clinical outcomes.

Researchers observed the incidence of HALT and reduced leaflet motion were frequently present in the bioprosthetic valves. According to Makkar, the incidence in the entire cohort was 10 percent at 30 days and increased to 24 percent at one year. In terms of TAVR vs. SAVR, the prevalence of HALT and reduced leaflet motion was significantly higher in TAVR than SAVR at 30 days, but not at one year.

In other findings, HALT was dynamic and spontaneously resolved (50 percent) in the absence of anticoagulation, while new HALT appeared in 20 percent of patients at one year. Makkar also noted a minimal but clinically insignificant increase in valve gradients was also seen as a result of HALT and reduced leaflet motion. No deaths or myocardial infarctions were seen in patients with HALT. While the pooled rates of death, stroke and thromboembolic events were numerically higher in patients with HALT, the data are inconclusive and only hypothesis generating, Makkar said.

Looking ahead, longer term follow-up and larger data sets will further clarify the impact on clinical outcomes. However, Makkar notes the findings do suggest that routine post-TAVR/SAVR CT scans, outside of research protocols are not indicated. Rather, he said, CTs should be prompted by increased gradients or thromboembolic events.

Keywords: TCT19, Transcatheter Cardiovascular Therapeutics, Thrombosis, Tomography, X-Ray, Percutaneous Coronary Intervention, Angiography

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