# Sclerotherapy embolism: a novel etiology for chronic thromboembolic pulmonary disease

## TL;DR

This paper reports a rare case series linking sclerotherapy procedures to chronic pulmonary artery obstruction, offering new insight into a possible cause of chronic thromboembolic pulmonary disease.

## Contribution

The study is the first to document a histopathological link between sclerotherapy and chronic pulmonary artery obstruction.

## Key findings

- Four patients with a history of sclerotherapy were found to have chronic pulmonary artery obstruction confirmed by histopathology.
- Post-surgery hemodynamic improvements and absence of recurrence suggest successful treatment via pulmonary endarterectomy.
- The findings highlight the importance of considering iatrogenic causes in unexplained pulmonary vascular disease.

## Abstract

Chronic thromboembolic pulmonary disease (CTEPD) includes both chronic thromboembolic pulmonary hypertension (CTEPH) and disease without pulmonary hypertension. Although the main cause of CTEPH is mostly due to thromboembolic events, other rare non-thrombotic etiologies may also contribute to chronic pulmonary artery obstruction. This case series presents a unique observation of foreign material embolization related to prior sclerotherapy procedures, confirmed histopathologically after pulmonary endarterectomy (PEA).

From a prospectively maintained database of 1,105 patients undergoing PEA between 2011 and 2025, four patients (three women and one man; median age 32.5 years, range: 28–41) with a history of sclerotherapy were identified. All underwent sclerotherapy for varicose vein treatment. They were referred for surgery with a preoperative diagnosis of CTEPD, with or without pulmonary hypertension. The final diagnosis was confirmed by histopathological examination of surgical specimens.

All four patients had segmental or lobar perfusion defects and vascular obstruction consistent with organized embolic material. Preoperative mean pulmonary artery pressure (mPAP) was 24.3 ± 7.4 mmHg, and mean pulmonary vascular resistance (mPVR) was 219.3 ± 104.6 dyn·s/cm⁻⁵. Although the surgery was challenging because of difficulty establishing dissection plane, no perioperative morbidity or mortality occurred. Postoperative hemodynamic improvement was observed, with mPAP reduced to 16.3 ± 1.5 and mean PVR to 119.3 ± 45.8 dyn·s/cm⁻⁵ (p > 0.05). The mean six-minute walk test distance increased from 381.5 ± 63.2 m preoperatively to 470.0 ± 66.8 m after surgery (p > 0.05). Histopathological analysis confirmed the presence of sclerotherapy-related foreign material in all cases. All patients had unilateral lobar obstruction. During a median follow-up of 50 months, no mortality or recurrence of symptoms or pulmonary hypertension was observed.

This report is the first case series to document a direct histopathological link between sclerotherapy and chronic pulmonary artery obstruction. These findings emphasize the need to consider iatrogenic etiologies in patients with unexplained pulmonary vascular disease and support the diagnostic and therapeutic value of PEA in selected cases.

The online version contains supplementary material available at 10.1186/s12890-025-04052-7.