Spontaneous Regression of Possible Transcatheter Aortic Valve Thrombosis Without Additional Anticoagulant: Two-Year Follow-Up

J INVASIVE CARDIOL 2017;29(5):E64.

Key words: transcatheter aortic valve implantation, leaflet thrombosis, computed tomography

An 84-year-old man received transfemoral transcatheter aortic valve implantation (TAVI) with a 23 mm Sapien XT (Edwards Lifesciences). Dual-antiplatelet therapy was continued for 6 months post TAVI, and aspirin alone used thereafter. Multidetector computed tomography (MDCT) using retrospective electrocardiography-gated scanning with contrast media was performed at hospital discharge, as well as at 6-month, 1-year, and 2-year follow-up exams. No findings were observed up to 6 months; however, two-dimensional MDCT revealed a new hypo-attenuated leaflet thickening (HALT) on the right and non-coronary cusp leaflets at 1 year after TAVI (Figure 1A, arrows; Video 1). Reduced leaflet motion was confirmed by four-dimensional, volume-rendered MDCT (Figure 1B). At the 2-year follow-up exam, two-dimensional MDCT (Figure 1C) and four-dimensional, volume-rendered MDCT (Figure 1D) revealed improved leaflet mobility (Video 2) with spontaneous regression of HALT on both cusps (arrowheads). Moreover, transthoracic echocardiography performed at the 1-year follow-up exam revealed a decrease in the indexed aortic valve area (from 1.43 cm² to 1.01 cm²) compared to the area at hospital discharge; no marked increase was observed in the mean aortic gradient (from 8 mm Hg to 9 mm Hg). The patient was asymptomatic without neurological events throughout the entire follow-up period; therefore, no antithrombotic agent was added.   

To our knowledge, this is the first reported patient in whom a subclinical HALT regressed spontaneously without any additional anticoagulant, along with recovery of leaflet mobility on four-dimensional MDCT over a follow-up period of 2 years. The HALT in this patient was not confirmed with histopathological examination. However, we suspected the HALT to be a transcatheter heart valve thrombosis, because it was a reversible abnormality and regressed spontaneously, along with improvement of the leaflet motion. 

Although anticoagulants could be effective for this phenomenon, they also increase bleeding risk and may not be beneficial in elderly patients. This finding provokes thought on appropriate antithrombotic strategies for possible leaflet thrombosis.

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From the ¹Department of Cardiology, Keio University School of Medicine, Tokyo, Japan; and ²Department of Diagnostic Radiology, Keio University School of Medicine, Tokyo, Japan.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Hayashida is a proctor for Edwards Lifesciences. Dr Jinzaki reports grants from Toshiba Medical Systems. The remaining authors report no conflicts of interest regarding the content herein.

Manuscript submitted September 30, 2016, provisional acceptance given October 1, 2016, final version accepted October 5, 2016.

Address for correspondence: Kentaro Hayashida, Department of Cardiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan. Email: k-hayashida@umin.ac.jp