Impact of Antithrombotic Regimen and Platelet Inhibition Extent on Leaflet Thrombosis Detected by Cardiac MDCT after Transcatheter Aortic Valve Replacement

Abstract

The impact of antithrombotic regimen and platelet inhibition extent on subclinical leaflet thrombosis (SLT) detected by cardiac multidetector computed tomography (MDCT) after transcatheter aortic valve replacement (TAVR) is not well established. Hypoattenuation affecting motion (HAM) has been proposed as a surrogate marker of SLT, and is characterized by hypoattenuated leaflet thickening (HALT) and concomitant reduction in leaflet motion (RELM). We sought to investigate (i) the prevalence of HAM and HALT after TAVR detected by MDCT, (ii) the predictors of SLT, (iii) the impact of oral anticoagulant (OAC) and platelet inhibition extent assessed by platelet reactivity index vasodilator stimulated phosphoprotein (PRI-VASP) and closure time adenosine diphosphate (CT-ADP) on SLT. Of 187 consecutive patients who underwent TAVR from 1 August 2017 to 31 March 2018, 90 of them had cardiac CT at relevant follow-up. Clinical, biological, echocardiographic, procedural characteristics and treatments were collected before, at discharge, and 1 year after TAVR. P2Y12 platelet inhibition extent and primary haemostasis disorders were investigated using platelet PRI-VASP and CT-ADP point-of-care assays. Eighty-five post-TAVR CTs out of 90 were ranked for clarity and assessed with sufficient diagnostic quality. HAM was evidenced in 13 patients (15.3%) and HALT in 30 patients (35%). Procedural characteristics, including aortic valve calcium score, annulus size, or procedural heparin regimens, were equivalent between groups. Likewise, no impact of P2Y12 inhibition (PRI-VASP) nor primary haemostasis disorders (CT-ADP) on SLT could be evidenced. No impact of SLT on valve deterioration evaluated by transthoracic echocardiography (TTE) and clinical events could be established at 12 months follow-up. By multivariate analysis, lack of oral anticoagulant therapy at discharge (HR 12.130 CI 95% (1.394–150.582); p = 0.028) and higher haemoglobin levels were evidenced as the sole independent predictors of SLT. In four patients with HAM, MDCT follow-up was obtained after initiation of OAC therapy and showed a complete regression of HAM. SLT was evidenced in a sizeable proportion of patients treated by TAVR and was mainly determined by the lack of oral anticoagulant therapy. Conversely, no impact of platelet inhibition extent on SLT could be evidenced.

Paradoxical Increase of Stroke in Patients with Defect of High Molecular Weight Multimers of the von Willebrand Factors following Transcatheter Aortic Valve Replacement

“…25,26 The recent demonstration that the development of bioprosthetic valve thrombosis is mainly platelet-independent emphasizes a primary role for contact phase and more likely to be efficiently targeted by OACs. 27,28 Initial enthusiasm for a liberal use of OACs was damped by the early discontinuation of the GALILEO study. 29 In this trial, efficacy and tolerance evaluation of rivaroxaban 10 mg/day combined with aspirin 75 mg/day for 3 months compared with conventional DAPT for 3 months showed an increase in all-cause mortality, thromboembolic, and bleeding events in the rivaroxaban group.…”

Impact of leaflet thrombosis on hemodynamics and clinical outcomes after bioprosthetic aortic valve replacement: A meta‐analysis

“…Anticoagulation seems to reduce the occurrence of subclinical LT more effectively than antiplatelets. Despite the RESOLVE and SAVORY registries mentioned in this article, the FRANCE‐TAVI registry experiment, which investigated subclinical thrombotic events in 12 804 patients, showed that LT rates were significantly lower in patients who received an anticoagulation regimen . Jimenez et al observed that lack of oral anticoagulant therapy at discharge was an independent predictor of MDCT‐defined LT in patients following TAVR.…”

Anticoagulation Therapy After Transcatheter Aortic Valve Replacement

“…JCM [20] TAVR: n = 85 114 days (median interval) -Mean transaortic gradient at 30 days and 1 year was similar between patients with and without subclinical leaflet thrombosis.…”

“…Thus, it is unlikely that patients received therapeutic anticoagulation at the time of CT in this series. Multiple other studies have reported a protective role of anticoagulation for subclinical leaflet thrombosis [13,18,20,25].…”