Clinical and laboratory risk factors of thrombotic complications after pacemaker implantation: a prospective study

Venous lesions, including obstruction and thromboembolism (VTE), are not uncommon after pacemaker implantation. The purpose of this prospective study was to assess the role of various patient and procedure-related risk factors in the development of these complications. A prospective venography-based study of 150 consecutive pacemaker implantations with a 6-month follow-up was conducted. Current case-control study included all cases (n = 47) with a new venous lesion, and their matched controls. Several surgical and technical factors, i.e. lead burden, choice of venous access, operator experience and procedure duration, as well as patient-related classic risk factors of VTE were assessed. Plasma markers of coagulation and endothelial activation [prothrombin fragment 1 + 2 (F1 + 2), D-dimer (DD), von Willebrand factor (vWF), thrombomodulin (Tm)] were used to evaluate the extent of acute surgical trauma. All cases with venous lesions were also screened for thrombophilia. None of the procedure-related variables were predictive of VTE. Mean levels of vWF, F1 + 2 and DD increased significantly (P < 0.001) and equally in both cases and controls. No single clinical factor predicted venous lesions, but significant (P < 0.05) clustering of classic clinical VTE risk factors was seen among the cases. Thrombophilia was overrepresented in patients with symptomatic pulmonary embolism (2/5, 40%). Pacemaker implantation induces a transient hypercoagulable state, but its degree does not predict subsequent venous thromboembolism, and neither did the grade of endothelial damage as reflected by plasma markers. The aetiology of these lesions seems to be multifactorial, and clustering of classic thrombotic risk factors plays a role in the pathogenesis.