Introduction and objectives: Thrombocytopenia frequently occurs after transcatheter aortic valve implantation (TAVI) but its impact is poorly understood. We aimed to analyze the incidence, clinical impact, and predictors of acquired thrombocytopenia after TAVI.

Methods: This retrospective multicenter registry included 3913 patients undergoing TAVI with a baseline platelet count of ≥ 100 *109/L. Acquired thrombocytopenia was defined as a decrease in baseline platelet count of ≥ 50% (early nadir ≤ 3 days and late nadir ≥ 4 days) post-TAVI. The primary endpoint was 30-day all-cause mortality and secondary endpoints were procedural safety and 2-year all-cause mortality.

Results: The incidence of acquired thrombocytopenia was 14.8% (early nadir: 61.5%, late nadir: 38.5%). Thirty-day mortality occurred in 112 (3.0%) patients and was significantly higher in those with thrombocytopenia (8.5% vs 2.0%, adjusted OR, 2.3; 95%CI, 1.3-4.2). Procedural safety was lower and 2-year mortality was higher in patients with thrombocytopenia vs those without (47.9 vs 33.0%; P < .001, and 30.2% vs 16.8%; HR, 2.2, 95%IC, 1.3-2.7) and especially in those with late nadir thrombocytopenia (54.2% vs 45.5%; P = .056, and 38.6% vs 23.8%, HR, 2.1; 95%CI, 1.5-2.9). Independent predictors of thrombocytopenia comprised baseline and procedural factors such as body surface area, absence of diabetes, poorer renal function, peripheral vascular disease, nontransfemoral access, vascular complications, type of transcatheter heart valve, and earlier TAVI procedures.

Conclusions: Acquired thrombocytopenia was common (15%) after TAVI and was associated with increased short- and mid-term mortality and decreased procedural safety. Moreover, late thrombocytopenia compared with early thrombocytopenia was associated with significantly worse clinical outcomes. Further investigations are needed to elucidate the etiologic mechanisms behind these findings.