FREQUENCY OF DISTRIBUTION PATTERNS OF COLLATERALS IN ILLEOFEMORAL THROMBOSIS

Abstract

Background:
Iliofemoral deep vein thrombosis (DVT) involves thrombus formation in the iliac and/or common femoral veins, posing a high risk for complications such as venous insufficiency and post-thrombotic syndrome. The body compensates through collateral vein development, which helps maintain venous drainage. However, the anatomical distribution and prevalence of these collaterals remain poorly documented. A clearer understanding can enhance diagnostic precision and support tailored therapeutic interventions.

Objective:
To evaluate the distribution patterns of collateral veins in patients with iliofemoral thrombosis and determine how demographic and clinical factors influence these patterns.

Methods:
This cross-sectional study included 60 patients (37 males, 23 females) aged 18–80 years (mean 47.7 ± 13.5 years) with confirmed iliofemoral thrombosis via Doppler ultrasound. Patients were selected using simple random sampling at the Diagnostic Radiology Department of Doctors Hospital and Medical Center, Lahore. All participants underwent contrast-enhanced CT venography using a Toshiba Aquilion scanner to assess collateral vein distribution above and below the inguinal ligament. A structured proforma recorded presence or absence of specific collaterals, and data were analyzed using SPSS version 22.0.

Results:
Thrombosis location was isolated above the inguinal ligament in 17 patients (28.3%), below in 12 patients (20.0%), and involved both regions in 31 patients (51.7%). Homolateral collaterals included internal iliac vein tributaries (65%), ascending lumbar veins (53.3%), and subcutaneous cavocaval pathways (46.7%). Contralateral collaterals were found in 41.7% (cross-pubic) and 31.7% (transpelvic). Below the inguinal ligament, medial thigh collaterals were observed in 61.7%, lateral in 65%, anterior in 51.7%, and posterior in 30% of patients.

Conclusion:
Collateral vein patterns in iliofemoral thrombosis show significant variability. Detailed imaging-based mapping supports the development of more precise and personalized management strategies. Future longitudinal studies are needed to validate these findings and explore their clinical implications.