Antithrombotic therapy and the risk of pocket hematoma after subcutaneous implantable cardioverter-defibrillator implantation

Abstract Introduction The PRAETORIAN trial, which randomized S-ICD versus TV-ICD in patients with a class I or IIa indication for ICD therapy, showed that clinically significant pocket hematomas were more frequent following S-ICD implantation. Many ICD recipients have comorbidities requiring anticoagulant (AC) and/or antiplatelet (AP) therapy, which increase the risk for hematoma formation post implantation. In contrast to TV-ICD implantation, little data exists regarding the optimal AC and AP strategy during S-ICD implantation to prevent pocket hematomas. Methods All patients who underwent de novo S-ICD implantations between February 2009 and January 2023 at our tertiary center were included. Data was collected retrospectively from electronic patient records. Clinically significant pocket hematomas were defined as an accumulation of blood at the pocket site within 30 days after S-ICD implantation, necessitating actions including applying a pressure bandage, surgical evacuation, drain insertion, a change in medication or an extended hospital stay or blood transfusion. Results A total of 348 patients were included of which 224 (64.4%) patients used antithrombotic therapy pre-implantation. Median age at implantation was 50 years (IQR: 36-61 years), 33.4% of the patients were female and the vast majority of implants were intermuscular (90.2%). Eighteen (5.2%) patients developed a clinically significant pocket hematoma. A total of 94 (27%) patients used AC therapy prior to the implantation of which 73 (21%) patients used a vitamin K antagonist (VKA). A total of 130 (37.4%) patients used AP therapy at baseline of which 49 (14.1%) patients were on dual AP therapy (DAPT). Continuation of VKA and continuation of DAPT with ticagrelor were independent predictors for pocket hematoma formation (p<0.001, and p<0.001 respectively). There were significantly more pocket hematomas in patients with continued VKA compared to patients with interrupted VKA (27.3 % (6/22) vs. 4.3% (2/47), respectively, p=0.011). Moreover, continuation of DAPT with ticagrelor was associated with significantly more pocket hematomas post implantation compared to continuation of DAPT with clopidogrel (4/12 vs 1/28, respectively, p=0.022). Conclusion This study showed that continuation of VKA during S-ICD implantation was associated with an increased risk of pocket hematoma formation compared to interruption of VKA. The continuation of DAPT with ticagrelor was an independent predictor of pocket hematoma formation and showed significantly more pocket hematomas compared to continuation of DAPT with clopidogrel. These findings support the need for specific peri-operative thrombotic therapy guidelines for S-ICD implantations to reduce the risk of pocket hematomas.