Pelvic venous disorders and orthostatic intolerance: A systematic review of diagnostic associations and treatment outcomes

Pelvic venous disorders (PeVD) are recognised causes of chronic pelvic pain; emerging evidence suggests that venous outflow obstruction or reflux can also provoke orthostatic intolerance (OI) by infra-diaphragmatic pooling and reduced preload. Diagnostic and therapeutic frameworks for this overlap remain poorly defined. We systematically searched PubMed, Ovid MEDLINE, Scopus, and Cochrane to 20 May 2025. Two reviewers extracted data; risk of bias used design-specific validated tools. Sixteen studies met criteria (4 case reports, 7 case series, 2 single-arm cohorts, 2 case-control, 1 cross-sectional), comprising 964 participants (93% female; age 7-67 years). Case-control data suggested left common iliac or left renal-vein compression is more prevalent in patients with postural tachycardia syndrome than in controls. Paediatric series linked left renal-vein entrapment with orthostatic symptoms and proteinuria. Imaging confirmation used duplex ultrasound, CT, CT-venography, intravascular ultrasound, and dynamic MRA with 4D-flow. Eleven studies reported interventions (iliac stenting, ovarian/internal-iliac embolization, superficial venous ablation, renal-vein transposition or robotic auto-transplantation). Orthostatic symptoms generally improved; cohorts using the Orthostatic Hypotension Questionnaire showed ∼50% mean reduction, and several stented patients no longer met POTS criteria. Follow-up was typically ≤12 months. Overall risk of bias was high for single-arm cohorts and moderate for case-control studies. Available evidence supports a biologically plausible link between pelvic venous obstruction and OI suggests PeVD-directed procedures can ameliorate OI in selected patients. Prospective, multicentre studies with standardized imaging thresholds, objective autonomic endpoints, and longer follow-up are needed to define patient selection and comparative effectiveness.