Popliteal aneurysms: Distortion and size related to symptoms

Objectives. To examine size and distortion of popliteal aneurysms (PA) in relation to symptoms produced at presentation. Methods. A prospective study of all PA presenting to a single unit 1988-1994. Wherever possible patients underwent angiography, duplex scanning and measurement of both PA diameter and the most proximal angle of distortion. Symptoms and measurements were noted at the time of first presentation. Results. Seventy-three patients presented with 116 PA. At initial diagnosis 44 PA (38%) were asymptomatic and 39 (34%) produced acute ischaemia. As the PA increased in diameter so did the degree of distortion (p < 0.0001). Size and distortion were greater in PA producing acute ischaemia or acute thrombosis than in asymptomatic PA (p < 0.01). Degree of distortion differentiated symptomatic from asymptomatic PA (p = 0.0066). Size was not significantly different between these two groups. For PA 3 cm or larger in diameter with greater than 45 degrees distortion sensitivity, specificity and positive and negative predictive values for thrombosis were 90, 89, 83 and 94%, respectively. Conclusion. Distortion and size can differentiate between PA producing different symptoms. Combining the two provides a reliable method of differentiating PA which should be managed by early elective repair.