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Subclinical Leaflet Thrombosis in Prosthetic Valves
Quick Takes
- Subclinical leaflet thrombosis is common both on transcatheter and surgical aortic valve replacements.
- Hypoattenuated leaflet thickening of bioprosthetic aortic valves is associated with restricted leaflet motion and increased valve gradients.
Study Questions:
What are the prevalence and outcomes of subclinical leaflet thrombosis on computed tomography (CT) of bioprosthetic aortic valves?
Methods:
This PARTNER 3 (The Safety and Effectiveness of the SAPIEN 3 Transcatheter Heart Valve in Low-Risk Patients With Aortic Stenosis) CT substudy evaluated low-risk patients with aortic stenosis randomized to transcatheter aortic valve replacement (TAVR) or surgical aortic valve replacement (SAVR), and performed cardiac CTs at 30 days and 1 year to evaluate for subclinical leaflet thrombosis by hypoattenuated leaflet thickening (HALT) and restricted leaflet motion (RLM).
Results:
There were 435 patients randomized in this study, with TAVR and SAVR performed in 221 and 214 subjects, respectively. HALT was observed in 10% of total cases at 30 days and 21% at 1 year. At 30 days, HALT was more frequent with TAVR versus SAVR (13% vs. 5%, p = 0.03), with no difference at 1 year (28% vs. 20%, p = 0.19). HALT observed at 30 days spontaneously resolved at 1 year in 54% of patients. At 30 days, all patients with HALT had RLM, and all patients without HALT had normal leaflet motion. Overall, there was no difference in aortic valve gradients between patients with versus without HALT, but patients with HALT noted both at 30 days and 1 year had higher mean gradients than those without HALT at both time periods (17.8 ± 2.2 mm Hg vs. 12.7 ± 0.3 mm Hg, p = 0.04). At 30 days, the pooled rate of death, stroke, transient ischemic attack, and thromboembolic complications was higher in those with versus without HALT (8.6% vs. 2.9%, relative risk, 3.0; 95% confidence interval [CI], 0.8-10.4).
Conclusions:
Subclinical leaflet thrombosis in low-risk aortic stenosis patients treated with bioprosthetic valves is common, and often spontaneously resolves. Patients with persistent HALT at both 30 days at 1 year have increased aortic valve gradients, and HALT is associated with increased pooled adverse events.
Perspective:
Subclinical leaflet thrombosis is common both in patients treated with TAVR and SAVR, with increased rates in TAVR at 30 days, but not at 1 year. There is a strong association between HALT and RLM, and the presence of HALT at both 30 days and 1 year was associated with increased aortic valve gradients. While the rate of adverse events was low, the pooled event rate was higher in patients with HALT at 30 days. It remains unclear whether treatment changes would alter these findings or improve outcomes, and this requires further study. Larger studies with longer-term follow-up that include additional TAVR devices are needed to better assess the clinical significance of subclinical leaflet thrombosis.
Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Valvular Heart Disease, Aortic Surgery, Cardiac Surgery and VHD, Interventions and Imaging, Interventions and Structural Heart Disease, Computed Tomography, Nuclear Imaging
Keywords: Aortic Valve Stenosis, Cardiac Surgical Procedures, Diagnostic Imaging, Heart Valve Diseases, Heart Valve Prosthesis, Ischemic Attack, Transient, Risk, Stroke, Thrombosis, Tomography, Tomography, X-Ray Computed, Transcatheter Aortic Valve Replacement, Vascular Diseases
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