Venous Stenting in Proximal Venous Outflow Obstruction: Outcome Predictors

Abstract

The objective of this study was to identify risk factors, including patient and surgical characteristics, associated with postoperative outcomes after iliac vein stenting for chronic proximal venous outflow obstruction (PVOO). The study is based on a composite retrospective and prospective database of 628 patients who underwent iliac vein stent placement for chronic PVOO at a single institution from January 2013 to April 2017. Patient characteristics, clinical presentation, and outcomes at 30 days, 90 days, 6 months, 1 year, and >1 year were queried. Univariate and multivariate ordinal regression, with stepwise backward elimination, was used to determine predictors of postoperative outcomes at various time points. Demographic characteristics included 351 (55.9%) women and mean age of 59.7 years. Edema was present in 568 (93%) patients. History of varicose veins or presence of varicose veins at the time of surgery was observed in 431 (70.4%) patients. Active ulceration was present in 94 (15%) patients. Clinical, Etiology, Anatomy, and Pathophysiology class 3 was noted for 69.4%. Bilateral stenting was performed in 385 (63.2%) patients. Univariate analysis showed that improvement in outcomes at 30 days was associated with edema (odds ratio [OR], 2.7; confidence interval [CI], 1.4-5.0; P = .002) and active ulceration (OR, 1.6; CI, 1.0-2.6; P = .03). Poorer outcomes at 30 days were associated with bilateral stenting (OR, 0.62; CI, 0.44-0.88; P = .007). At 90 days, improvement was associated with varicose veins (OR, 1.6; CI, 1.0-2.4; P = .03), edema (OR, 3.2; CI, 1.5-6.8; P = .002), and history of vein surgery (OR, 1.7; CI, 1.2-2.5; P = .008). At 6 months, univariate analysis demonstrated that being female (OR, 0.62; CI, 0.40-1.00; P = .03) resulted in poorer outcomes. Patients who had edema had better outcomes at 1 year (OR, 5.5; CI, 1.8-17.4; P = .003) and at >1 year (OR, 6; CI, 1.5-24.5; P = .013). At 30 days, multivariate analysis showed that the effects of edema and bilateral stenting persisted. At 90 days, the effects of edema and history of vein surgery persisted. In addition, multivariate analysis revealed that a history of deep venous thrombosis (DVT; OR, 0.405; CI, 0.213-0.771; P = .0059) resulted in poorer outcomes at 90 days, whereas active ulcerations (OR, 2.447; CI, 1.337-4.479; P = .0037) resulted in better outcomes. The effect of sex on outcomes at 6 months persisted. At outcomes >1 year, multivariate analysis revealed that acute DVT (OR, 0.111; CI, 0.015-0.838; P = .0331), DVT history (OR, 0.313; CI, 0.116-0.843; P = .0216), and bilateral stenting (OR, 0.349; CI, 0.132-0.921; P = .0335) were associated with poorer outcomes. Outcomes of iliac vent stenting are affected by multiple factors. Patients with edema are likely to benefit from iliac vein stenting. The benefits of venous stenting in active ulcers warrant further investigation as unreported here is the frequency of negative venography and IVUS among patients with active ulcers. Our findings may guide selection of patients and better counsel patients about the outcomes of venous stents in chronic PVOO.