Association and post-iliac vein stenting symptom improvement of postural orthostatic tachycardia syndrome and orthostatic intolerance with pelvic venous disorders: two retrospective studies

Background Patients with Postural Orthostatic Tachycardia Syndrome (POTS) and Orthostatic Intolerance (OI) commonly present with symptoms suggestive of Pelvic Venous Disorders (PeVD). The presence of PeVD may contribute to orthostatic symptoms in these patients due to venous obstruction with stasis and pooling. Iliac vein compression, a PeVD, has historically been treated with iliac venous stenting. The authors hypothesize that patients with POTS frequently have findings of PeVD, that venous outflow obstruction from iliac vein compression exacerbates POTS/OI symptomatology, and that treating PeVD improves POTS/OI symptoms. Methods This paper reports results from two studies at two different institutions with a partially overlapping patient population. The first was a retrospective cross-sectional observational study of patients with POTS/OI who presented to Emory University Cardiology (Atlanta, GA, USA) from October 2019 to June 2023. We aimed to evaluate the prevalence of concurrent POTS/OI and PeVD using screening pelvic venous ultrasound, MR and/or CT, compared to venogram with intravascular ultrasound (IVUS). We secondarily evaluated the efficacy of each imaging modality in screening accuracy for PeVD. The second study was a retrospective review of medical records for 271 female patients with POTS/OI who received treatment of PeVD with iliac vein stenting from June 2019 to November 2024 at Minimally Invasive Procedure Specialists (Highlands Ranch, CO). The primary objective of this study was to explore quality of life (QoL) outcomes in female patients with POTS/OI before and after treatment. The secondary objective was to record the prevalence of associated pelvic pain, systemic symptoms, and response to therapy in this population. Findings In the first cohort, 129 patients (84% cis female) with a diagnosis of POTS/OI and symptoms of PeVD were assessed by standard imaging for venous pathology. 107 patients (83%) had confirmed pelvic venous compression (iliac vein, renal vein, or both) or pelvic venous congestion on imaging with at least one screening modality. All screening modalities were relatively insensitive in detecting iliac venous compression compared with venography and IVUS. In the second cohort, following iliac vein stenting, significant improvements were seen in Orthostatic Hypotension Questionnaire (OHQ) composite scores at three months (p < 0·001) and at 12 months (p < 0·001). The OHQ Symptom Assessment (OHSA) and Daily Activities Scale (OHDAS) subscores, International Pelvic Pain Society (IPPS) score, Pelvic Congestion Syndrome (PCS) score, Pelvic Pain and Urgency/Frequency Symptom Scale (PUF) score, and Ancillary symptom score all demonstrated statistically significant decreases at three months that persisted at 12 months (all p < 0·001) as well. Interpretation The high prevalence of PeVD in POTS/OI patients suggests an association between the two diagnoses. In the absence of expert clinical review, screening with US, CT, and MR may not be sufficient to rule out PeVD. Significant improvements were seen in QoL in patients with POTS/OI and PeVD who underwent iliac vein stenting. These results call for additional trials to examine the clinical and hemodynamic effects of venous stenting on POTS/OI symptomatology and associated systemic symptoms, including pelvic pain. Funding These studies received no funding.