Iliac Vein Stenosis: An Underdiagnosed Cause of Pelvic Venous Insufficiency

Abstract

Pelvic venous insufficiency (PVI) is a common cause of chronic pelvic pain in women. Reflux in the ovarian veins, with or without an obstructive venous outflow component, is reported to be the primary cause of PVI. The degree to which venous outflow obstruction plays a role in PVI is currently ill-defined. We retrospectively reviewed the charts of 220 women who underwent 227 procedures for PVI at the Center for Vascular Medicine from January 2012 to September 2015. Assessments and treatments consisted of an evaluation for other causes of chronic pelvic pain by a gynecologist; visual analog scale (VAS) for pain score before and after intervention; complete venous duplex ultrasound examination; and clinical, etiologic, anatomic, and pathophysiologic (CEAP) classification. All patients underwent diagnostic venography of their pelvic and left ovarian veins as well as intravascular ultrasound (IVUS) examination of their iliac veins. Patients were treated in one of six ways: ovarian vein embolization (OVE) alone (chemical ± coils), OVE with staged iliac vein stenting, OVE with simultaneous iliac vein stenting, iliac vein stenting alone, OVE with venoplasty, and venoplasty alone. In patients with ovarian vein reflux and iliac vein stenosis, it was our policy to treat the ovarian veins first and to stage the iliac vein stenting. In patients with travel restrictions, OVE and stenting were performed simultaneously. In addition to VAS scores before and after intervention, symptoms were also assessed in terms of complete, partial, or no symptom resolution. Of the 220 women treated, the average age and number of pregnancies were 44.8 ± 10.4 years and 3.08 ± 2.21, respectively. CEAP class for 181 patients was documented as follows: C0, 16; C1, 62; C2, 45; C3, 42; C4, 13; C5, 2; and C6, 1. Treatment distribution was the following: OVE, n = 39; OVE with staged stenting, n = 88; OVE with simultaneous stenting, n = 32; stenting alone, n = 50; OVE with venoplasty, n = 8; and venoplasty alone, n = 3. Seven patients in the OVE and stenting groups (staged) and one patient in the OVE with venoplasty group required a second embolization of the left ovarian vein. Eighty-two percent of patients (181/220) demonstrated an iliac stenosis >50% by IVUS. Average stent diameter was between 20 and 22 mm. Of the six therapies employed, complete, partial, and no symptom resolution was observed as follows: stenting alone, 70%, 20%, 10%; OVE with stenting, 58%, 36%, 5%; OVE alone, 35%, 54%, 5%; OVE with venoplasty, 50%, 50%, 0%; and venoplasty alone, 33%, 63%, 0%. Dyspareunia and fullness responded best to OVE with stenting and worst to OVE alone. Average VAS scores before and after intervention for the entire cohort were 8.45 ± 1.11 and 1.86 ± 1.61 (P ≤ .001). Scores before and after intervention between groups did not differ except for venoplasty alone (P ≤ .01). To assess the role of stenting for alleviation of pain in patients with ovarian vein reflux and iliac vein occlusive disease, we analyzed the OVE staged and simultaneous groups separately. In the staged group, only 9 of 88 patients reported a decrease in the VAS score with OVE alone. The remaining 79 reported no improvement. After stenting, a significant decrease in VAS score was reported. The VAS score decreased from 8.6 ± 0.89 before OVE to 7.97 ± 2.10 after OVE (P ≤ .01). After the planned staged stenting, VAS score decreased to 1.33 ± 2.33 (P ≤ .001). Similarly, in the simultaneous group, preintervention scores were 8.63 ± 1.07 and decreased to 2.36 ± 2.67 after OVE with stenting (P ≤ .001). The postintervention scores between the staged and simultaneous groups were significantly different (P ≤ .04). The majority of patients in our series (82%) demonstrated a significant iliac vein stenosis. These observations indicate that the incidence of iliac vein outflow obstruction in PVI is greater than previously reported. In patients with combined ovarian vein reflux and iliac vein outflow obstruction, our data suggest that pelvic venous outflow lesions should be treated first and that ovarian vein reflux should be treated only if symptoms persist. We recommend that during pelvic venography, IVUS should be performed routinely as part of the diagnostic evaluation.