Upper extremity deep venous thrombosis and stenosis after implantation of pacemakers and defibrillators; A prospective study MORTEZA SAFI 1,2 , MOHAMMAD ALI AKBARZADEH 1,2 , AZADEH AZINFAR 1,2 , MOHAMMAD HASAN NAMAZI 1,2 , ISA KHAHESHI 1,2 1 Cardiovascular Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran 2 Cardiology Department, Shahid Modarress Hospital, Tehran, Iran Background. Obstruction of the access vein following cardiac pacemaker and defibrillator implantation is a common complication. However, the exact incidence and contributing risk factors are unknown. The aim of this study is to determine the incidence and analyze the contribution of each risk factor. Methods. 57 consecutive patients candidate for their first transvenous pacemaker, implantable cardioverter-defibrillator (ICD), or cardiac resynchronization therapy device implantation were enrolled. After implantation, venography of the ipsilateral peripheral arm was performed. Patients underwent their second venography after the follow-up period of 3 to 6 months. Results. 42 patients (13 females, mean age 59.71 ± 12.33) completed the study. The follow- up venography showed significant venous obstruction (more than 50%) in 9 (21%) patients, but in none of the individuals, venography revealed total occlusion of the veins. Patients with obstruction had more leads in their veins (2.56 ± 0.53 vs 1.58 ± 0.71, P = 0.001). Venous obstruction was significantly more prevalent in patients with implanted cardiac resynchronization therapy device compared with an ICD or pacemaker (p = 0. 01). Age, gender, diabetes mellitus, hypertension, ischemic heart disease and antiplatelet consumption did not reveal any other contribution to the risk of thrombosis. In multivariate analysis, total lead number was a positive predictor for venous occlusion (P = 0.015, OR:19.2, and CI: 1.7-207.1). Conclusion. Venous obstruction is relatively frequent after pacemaker or ICD implantation. This study also shows that pacemaker and ICD leads have a similar risk for lead-related venous obstruction. However, patients with multiple leads are associated with an increased risk. Key words: Complications; Venous obstruction; Risk factors; Pacemaker; Implantable cardio- verter-defibrillator. INTRODUCTION Obstruction of the access vein is a common and well-known complication following cardiac pacemaker and defibrillator implantation [1, 2]. Although the clinical symptom is rare, it can make the follow-up procedures such as system revision and lead extraction or upgrade difficult or even impossible [2, 3]. This complication was mostly evaluated at the time of generator replacement as a late complication, but in a few studies, it has been shown that it can occur very soon (in the first three months) after implantation, and its incidence is not really low in the first few months [4-6]. One the other hand, the risk factors for the development of device-associated venous obstruction have not been clearly determined till now [7]. Such data can provide insight into thrombotic risks among patients prior to implantation and may be used to guide prophylactic strategies in high risk patients. MATERIALS AND METHODS This prospective observational study was per- formed at the Department of Cardiology of Modarress Hospital, Tehran, Iran. The study protocol was approved by the institutional ethic committee of cardiovascular research center of Shahid Beheshti University of Medical Sciences. Written informed consent was obtained from all participants prior to the device implant. Between November 2015 and April 2015, consecutive patients above 18 years of age who were admitted to our institution for their first transvenous implant of pacemaker, implantable cardioverter-defibrillator (ICD), or cardiac resyn- ROM. J. INTERN. MED., 2017, 55, 3, 139–144