Impact of On-Clopidogrel Platelet Reactivity on Incidence of Hypoattenuated Leaflet Thickening After Transcatheter Aortic Valve Replacement

Objectives

To assess the impact of on-clopidogrel platelet reactivity (PR) on HALT, the authors prospectively tested whether patients with below-median on-clopidogrel PR have a lower incidence of HALT compared with those with above-median on-clopidogrel PR.

Long-Term Follow-Up of Hypoattenuated Leaflet Thickening After Transcatheter Aortic Valve Replacement

BackgroundEarly hypoattenuated leaflet thickening (HALT) occurs in at least 10% of all transcatheter aortic valve replacement (TAVR) patients. The long-term prognostic impact of HALT is uncertain.ObjectivesThe aim of this study was to assess the long-term risk of early HALT post-TAVR.MethodsWe report outcome data from our prospective observational registry with post-TAVR computed tomography angiography performed between May 2012 and December 2017. The outcomes were survival, cardiovascular mortality, ischemic cerebrovascular events, and symptomatic hemodynamic valve deterioration.ResultsEarly HALT was diagnosed in 115 (16.0%) of 804 patients. During a median follow-up of 3.25 years, survival rates did not differ significantly between patients with and without HALT (Kaplan-Meier 3-year estimates for survival 70.1% vs 74.0%, P = 0.597). The 3-year cardiovascular mortality rate was 13.2% versus 11.3% (with vs without HALT, P = 0.733). The 3-year event rate for cerebrovascular events was 2.0% versus 4.4% (with vs without HALT, P = 0.246), and the 3-year event rate of symptomatic hemodynamic valve deterioration was 9.4% versus 1.5% (with vs without HALT, P < 0.001). Multivariable analysis revealed the following predictors of symptomatic hemodynamic valve deterioration: HALT (HR: 6.10; 95% CI: 2.59-14.29; P < 0.001), the mixed valve–type group (HR: 6.51; 95% CI: 2.38-17.81; P < 0.001), and prosthesis diameter (HR valve size per 3 mm [HR: 0.37; 95% CI: 0.17-0.79]; P = 0.011).ConclusionsDuring a median follow-up of more than 3 years, HALT was not associated with mortality or cerebrovascular events. However, we observed an association of HALT with symptomatic hemodynamic valve deterioration.     

Bioprosthetic Aortic Valve Leaflet Thickening in the Evolut Low Risk Sub-Study

BackgroundSubclinical leaflet thrombosis has been reported after bioprosthetic aortic valve replacement, characterized using 4-dimensional computed tomographic imaging by hypoattenuated leaflet thickening (HALT) and reduced leaflet motion (RLM). The incidence and clinical implications of these findings remain unclear.ObjectivesThe aim of this study was to determine the frequency, predictors, and hemodynamic and clinical correlates of HALT and RLM after aortic bioprosthetic replacement.MethodsA prospective subset of patients not on oral anticoagulation enrolled in the Evolut Low Risk randomized trial underwent computed tomographic imaging 30 days and 1 year after transcatheter aortic valve replacement (TAVR) or surgery. The primary endpoint was the frequency of HALT at 30 days and 1 year, analyzed by an independent core laboratory using standardized definitions. Secondary endpoints included RLM, mean aortic gradient, and clinical events at 30 days and 1 year.ResultsAt 30 days, the frequency of HALT was 31 of 179 (17.3%) for TAVR and 23 of 139 (16.5%) for surgery; the frequency of RLM was 23 of 157 (14.6%) for TAVR and 19 of 133 (14.3%) for surgery. At 1 year, the frequency of HALT was 47 of 152 (30.9%) for TAVR and 33 of 116 (28.4%) for surgery; the frequency of RLM was 45 of 145 (31.0%) for TAVR and 30 of 111 (27.0%) for surgery. Aortic valve hemodynamic status was not influenced by the presence or severity of HALT or RLM at either time point. The rates of HALT and RLM were similar after the implantation of supra-annular, self-expanding transcatheter, or surgical bioprostheses.ConclusionsThe presence of computed tomographic imaging abnormalities of aortic bioprostheses were frequent but dynamic in the first year after self-expanding transcatheter and surgical aortic valve replacement, but these findings did not correlate with aortic valve hemodynamic status after aortic valve replacement in patients at low risk for surgery. (Medtronic Evolut Transcatheter Aortic Valve Replacement in Low Risk Patients; NCT02701283)     

Subclinical leaflet thrombosis following transcatheter aortic valve replacement

Since the inception of transcatheter aortic valve replacement (TAVR), there have been significant reductions in complications due to improvements of transcatheter heart valve (THV) designs and technologies. Given expanding TAVR applications, reducing complications further and better understanding THV durability has become a focus within the structural heart space. Recently, dedicated cardiac computed tomographic angiography (CTA) performed at 1 month post‐TAVR has identified subclinical leaflet thrombosis (SLT), with rates as high as 40%. From the SLT imaging hallmarks of hypoattenuated leaflet thickening (HALT) to hypoattenuation affecting motion (HAM), a postulated timeline of THV thrombosis advancing to clinical symptoms can be recognized. This review article focuses on leaflet thrombosis particularly following TAVR explaining the spectrum of this disease process, its diagnosis, current treatment options, and future directions in the field.