Early Platelet Reduction After Transcatheter Aortic Implantation: Results from the PORTRAIT Study

Objective: Platelet count reduction (PR) is a not fully understood phenomenon occurring after trans-catheter aortic valve implantation (TAVI). Moreover, literature reported that patients receiving balloon-expandable valves (BEV) experienced a higher PR than self-expandable valves (SEV) patients. The study aimed to investigate the occurrence and the clinical impact of PR in TAVI patients. Methods: 1.122 adult patients undergone trans-catheter aortic valve implantation (TAVI) from July 2009 to January 2020 in 9 different centres joining the Post-Operative Thrombocytopenia After Bio-prosthesis Implantation study. BEV and SEV were propensity score-matched in a 1:1 ratio. Platelet count variation, early post-operative adverse events, and in-hospital mortality were analyzed. Results: A total of 632 patients (BEV:316; SEV:316) were matched. A mixed regression model for repeated analyzes showed that post-procedural platelet count varied according to a parabolic curve in all patients (estimate:-4,27, standard error:4,75, p:0,369; Figure 1). Platelet count varied similarly in both BEV and SEV patients (p=0,472). The minimum platelet count value occurred three days after implantation (PID3) (BEV:157 vs. SEV:159; p:0,081). On PID3, 14,6% of patients (92/632) had a platelet count <100.000/uL (BEV:51/316; SEV:41/316; p=0,266), that was significantly associated to a high need for blood product transfusions (red blood cells, p<0,001; fresh frozen plasma, p=0,007; platelet, p=0,001), a longer in-hospital length of stay (p<0,001), and increased in-hospital mortality rate (p<0,001). Conclusions: Transcatheter aortic valve implantation is associated with a significant but transient PR, regardless the type of valve. TAVI patients who experience a PR below 100.000/uL are exposed to high rate of complication and in-hospital mortality rate. Further prospective studies are warrantied to investigate and explain mechanism and related outcomes.