# Prevalence and risk of deep vein thrombosis recurrence in Thai patients with iliac compression syndrome

## TL;DR

This study found that 37% of Thai patients with leg blood clots had iliac compression syndrome, which was linked to a higher risk of future clots.

## Contribution

The study is the first to report the prevalence of iliac compression syndrome in Thai DVT patients and its association with DVT recurrence.

## Key findings

- Iliac compression syndrome was found in 37% of DVT patients.
- Patients with ICS had a 4.71 times higher risk of recurrent DVT.
- Younger age was significantly associated with the presence of ICS.

## Abstract

Iliac compression syndrome (ICS) results from compression of the left common iliac vein by the overlying right common iliac artery. The true prevalence of ICS remains unknown.

To study the prevalence of ICS in patients with deep vein thrombosis (DVT) of the legs and to evaluate outcomes, including recurrent DVT, pulmonary embolism, and postthrombotic syndrome, in ICS patients.

We conducted a retospective study from January 2015 to December 2023. Patients objectively confirmed diagnosis of DVT who underwent imaging either CT or MRI of the lower abdomen were included. The imaging studies were reviewed by 2 radiologists.

Among the 180 patients included, the prevalence of ICS was 37.2% (67/180). Left leg DVT was more frequent in ICS patients than in non-ICS patients (62.7% vs 23.9%; P = .01). There was no significant difference in iliac vein involvement (34.3% vs 22.1%; P = .07), pulmonary embolism (13.4% vs 20.4%; odds ratio [OR], 0.61; 95% CI, 0.3-1.4; P = .24), or postthrombotic syndrome (4.5% vs 1.8%; OR, 2.60; 95% CI, 0.4-16.0; P = .30). Recurrent DVT was more frequent in ICS patients (17.9% vs 4.4%; OR, 4.71; 95% CI, 1.6-14.1; P = .003). Factors significantly associated with recurrent DVT were ICS (OR, 8.26; 95% CI, 2.03-33.66; P = .003), previous venous thromboembolism (OR, 34.29; 95% CI, 7.38-159.1; P < .001), and autoimmune diseases (OR, 6.31; 95% CI, 1.47-26.96; P = .01).

The prevalence of ICS in DVT patients in this study was 37%. ICS was associated with an increased risk of recurrent DVT. ICS might be an underinvestigated contributor to recurrent DVT and warrants further exploration.

•Prevalence and clinical consequences of iliac compression syndrome (ICS) remain unclear.•ICS was identified by abdominal CT or MRI imaging in DVT patients.•ICS prevalence was 37% with younger age significantly associated with its presence.•Patients with ICS had significantly higher recurrent DVT which suggests an under investigated contributor.

Prevalence and clinical consequences of iliac compression syndrome (ICS) remain unclear.

ICS was identified by abdominal CT or MRI imaging in DVT patients.

ICS prevalence was 37% with younger age significantly associated with its presence.

Patients with ICS had significantly higher recurrent DVT which suggests an under investigated contributor.