Objective: This study investigated the proportion of silent venous obstruction in patients who underwent pacemaker or lead reimplantation for various reasons. We also investigated independent predictors or risk factor of venous obstruction in this patient population.
Methods: Seventy-three patients who underwent pacemaker pulse generator and/or lead reimplantation in our institution between 2007 and 2010 were enrolled for this retrospective case-control study. Prior to procedure, patients underwent ipsilateral venography. Patients' venographies were classified as non-significant obstruction (stenosis ≤70%, including normal venogram), significant obstruction (stenosis >70%) and complete obstruction. Continuous and categorical data were compared with Mann-Whitney U test and Chi-square statistics respectively. Logistic regression analysis was used to identify independent predictors of venous obstruction.
Results: Complete or significant silent central venous obstruction (CVO) proportion was detected as 9.5% (n=7). Basal characteristics of patients with or without CVO were comparable. Significantly increased pacemaker pocket erosion incidence (57% vs 0%, p=0.001, in groups with and without CVO respectively) and significantly higher mean pacemaker age (15.3 ± 10.2 years vs 10.4 ± 5.1 years, p=0.047, in groups with and without CVO respectively) were found in group with CVO. Pacemaker pocket erosion (OR 3.00; 95% CI 1.024-9.302; p=0.001), higher pacemaker age (OR 1.33; 95% CI 1.026-1.733; p=0.02) were found as independent CVO predictors in multiple logistic regression analysis. Correlation analysis also revealed a significant correlation between previous or current pacemaker pocket erosion and CVO (r=0.80, p=0.001).
Conclusion: Ipsilateral venography is a useful procedure prior to pacemaker or lead reimplantation to detect CVO. In addition to the increased pacemaker age, current or past history of erosion and infection at pacemaker pocket are probable clinical conditions related to CVO. These clinical conditions create a predisposition to CVO with unknown mechanisms, according to the results of this preliminary study.