Wound haematoma following defibrillator implantation: incidence and predictors in the Shockless Implant Evaluation (SIMPLE) trial.

Aims: Pocket haematoma is a common complication after defibrillator [implantable cardioverter defibrillator (ICD)] implantation, which is not only painful, but also increases the risk of device-related infection, and possibly embolic events. The present study seeks to evaluate the rate and predictors of clinically significant pocket haematoma.

Methods and results: This study included 2500 patients receiving an ICD in the SIMPLE trial. A clinically significant pocket haematoma was defined as a haematoma that required re-operation or interruption of oral anticoagulation (OAC) therapy. Clinically significant pocket haematoma occurred in 56 of 2500 patients (2.2%) of which 6 (10.7%) developed device-related infection. Patients who developed pocket haematoma were older (mean age 67.6 ± 8.8 years vs. 62.7 ± 11.6 years, P < 0.001), were more likely to have permanent atrial fibrillation (30.4 vs. 6.7%, P < 0.001) and a history of stroke (17.9 vs. 6.7%, P = 0.004), or were more likely to receive peri-operative OAC (50.0 vs. 28.4%, P < 0.001), unfractionated heparin (16.1 vs. 5.2%, P = 0.003), or low-molecular-weight heparin (37.5 vs. 17.5%, P < 0.001). Independent predictors of wound haematoma on multivariable analysis included the use of heparin bridging (OR 2.65, 95% CI 1.48-4.73, P = 0.001), sub-pectoral location of ICD (OR 2.00, 95% CI 1.12-3.57, P =0.020), previous stroke (OR 2.47, 95% CI 1.20-5.10, P = 0.015), an upgrade from permanent pacemaker (OR 2.52, 95% CI 1.07-5.94, P = 0.035), and older age (OR 1.03, 95% CI 1.00-1.06, P = 0.049).

Conclusion: Pocket haematoma remains an important complication of ICD implantation and is associated with a high risk of infection. Independent predictors of pocket haematoma include heparin bridging, prior stroke, sub-pectoral placement of ICD, older age, and upgrade from a pacemaker.