Cardiovascular computed tomography in the evaluation of post-TAVI prosthesis dysfunction: the thin line between hypo attenuated leaflet thickening and clinical valve thrombosis.

Abstract

It is accepted that hypo attenuated leaflet thickening (HALT) can be detected in 12% and 32% of transcatheter aortic valve implantation (TAVI) patients on oral anticoagulation or dual antiplatelet therapy at 3 months, respectively.1 Clinically relevant TAVI thrombosis is rare, with up to 1% incidence.2 We present the case of an 86-year-old male with a history of ischemic cardiomyopathy, atrial fibrillation (on apixaban 5 mg BID), and 4 months post-TAVI (Sapien 3–29 mm) who presented to the Emergency Department with worsening dyspnea and elevated cardiac biomarkers: HS-Tn (1689 ng/L) and NT-proBNP (>5000 pg/mL). Echocardiogram showed new severe systolic dysfunction (left ventricular EF = 30%) and elevated gradients (compared to the basal post-TAVI study) with limited visualization of the valve (central figure, Panels A and B). He underwent invasive coronary angiography, which showed no coronary artery disease progression as to explain the clinical changes. Given the rapidly worsening clinical status, a cardiovascular computed tomography (CCT) was ordered over transesophageal echocardiogram for better evaluation. The CCT was acquired using retrospective gating without ECG dose modulation (IQon, Philips) for high-quality full-cycle images (Panels C–F). There was severe symmetrical tri-leaflet thickening with sparing of the distal tips (meniscal shape), classically described in HALT.3 The Hounsfield units were more consistent with thrombus (<100 HU) (Panel C), and significantly reduced tri-leaflet motion was also noted on functional images (see Supplementary data online, Video S1). Despite being treated with i.v. heparin and guideline-directed medical therapy for HFrEF, the patient developed refractory cardiogenic shock and expired. The best antithrombotic regimen for patients undergoing TAVI remains controversial.4 Bioprosthetic valve thrombosis involves a spectrum with different grades of clinical manifestation. The CCT is paramount for establishing the etiology of the dysfunction and providing prognostic information for patient management.5