VESS06 - Percent Thrombus Predicts Popliteal Artery Aneurysm Related Thromboembolic Events

Objectives: Popliteal artery aneurysms (PAAs) are associated with high morbidity and mortality. Current guidelines recommend operative repair for PAAs with a diameter greater than 20 mm based on very limited evidence. The objective of this study was to identify clinical and anatomic characteristics of PAA associated with limb threatening and thromboembolic events (TEs).

Methods: This multi-institutional retrospective cohort was derived from the Massachusetts General Brigham Research Patient Data Registry. The registry was queried for all patients with a PAA from 2008 to 2022 and chart review was performed for presence of a PAA, defined as greater than 1cm on any imaging modality. Duplex ultrasound (DUS) characteristics of PAAs were abstracted by certified registered physicians in vascular interpretation. The primary outcome was symptom status, which was divided into three categories: symptomatic PAA with documented claudication or chronic limb ischemia (CLI), limb threatening PAA with a TE, acute limb ischemia, or rupture, and asymptomatic PAA without symptoms or limb threatening events.

Results: There were 470 PAAs identified in 331 patients. The mean age was 74 years old at diagnosis, 94% of patients were white, and 97% of patients were male. Cardiovascular comorbidities were prevalent in and similar between all patient groups studied, and almost all patients were on anticoagulation or antiplatelet therapy at the time of diagnosis (96%). Patient comorbidities and medications were not associated with symptom status. Higher percent thrombus was significantly associated with PAA with a TE, PAAs with a limb threatening event, and symptomatic PAAs in a multivariable model including age (Table I). Channel area, thrombus area, largest diameter, and mural thrombus did not have any significant association with symptom status or limb threatening events. A largest diameter threshold of 20.4 mm was predictive of a TE (sensitivity 78.1%, specificity 40.5%), but percent thrombus threshold of 62% outperformed largest diameter as a predictor of a TE (sensitivity of 81.3%, specificity 52.0%) (Fig 1).

Conclusions: Percent thrombus was significantly associated with TEs, symptomatic PAAs, and limb threatening events, whereas diameter was not significantly associated with any symptom group. Percent thrombus greater than 62% outperformed largest diameter as a predictor of a TE. This analysis supports the use of percent thrombus in identifying high risk PAAs that warrant repair.