Incidence, characteristics, and treatment of valve thrombosis after TAVR

Certain studies have carried out a tomographic follow-up of patients who underwent transcatheter aortic valve replacement (TAVR) and described the frequency of leaflet thrombosis; however, in most cases, it is unclear whether this finding requires some sort of intervention. The difference between this work and those previously published is that this study is not focused on imaging, it is centered on the clinical symptoms of this event.

This retrospective analysis included 642 consecutive patients who underwent TAVR between 2007 and 2015 (305 patients had self-expanding valves; 281 received balloon-expandable valves, and 56 received mechanically expanding valves). Oral anticoagulation was indicated in 261 patients, while 377 patients received dual-antiplatelet therapy.

The global incidence of clinical valve thrombosis was 2.8% (n = 18). No patient receiving anticoagulation developed thrombosis.

Of all detected thrombosis cases, 13 patients had a balloon-expandable valve, 3 had a self-expanding valve, and 2 had a mechanically expanding valve. Thrombosis occurred significantly more frequently with balloon-expandable valves (odds ratio [OR]: 3.45; 95% confidence interval [CI]: 1.22 a 9.81; p=0.01) and in valve-in-valve procedures (OR: 5.93; 95% CI: 2.01 to 17.51; p = 0.005). The mean time from procedure to diagnosis of valve thrombosis was 181 days. In all thrombosis cases, computerized tomography showed hypoattenuating areas with reduced leaflet motion, which was associated with a mean gradient of 34 ± 14 mmHg and a valve area of 1.0 ± 0.46 cm².

Initiation of oral anticoagulation resulted in significant reduction of gradient and improvement of patient dyspnea. No thrombosis was associated to cardiovascular death.

Conclusion

Clinical transcatheter valve thrombosis is more common than previously suspected, and it is characterized by dyspnea, hypoattenuating areas in imaging, and increased pro-brain natriuretic peptide (proBNP) levels. Oral anticoagulation proved to be effective in both prevention and treatment of this event. The ideal antithrombotic therapy after transcatheter valve replacement is still unknown.

Original title: Clinical Bioprosthetic Heart Valve Thrombosis After Transcatheter Aortic Valve Replacement. Incidence, Characteristics, and Treatment Outcomes.

Reference: John Jose et al. J Am Coll Cardiol Intv 2017;10:686-97.

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