Popliteal aneurysms: controversies in their management

Natural history, growth rates, and treatment of popliteal artery aneurysms

BACKGROUND

The natural history of a cohort of patients monitored for popliteal artery aneurysms (PAAs) has not been well described. A prevailing uncertainty exists regarding the optimal surveillance strategies and timing of treatment. The primary aim of the present study was to describe the care trajectory of all patients with PAAs identified at two tertiary vascular centers, both in surveillance and eventually treated. The secondary aim was to define the PAA growth rates.

METHODS

A retrospective, multicenter cohort study was performed of all patients with PAAs at two vascular centers in two countries (Sweden, 2009-2016; New Zealand, 2009-2017). Data were collected from electronic medical records regarding the comorbidities, treatment, and outcomes and analyzed on a patient- and extremity-specific level. Treatment was indicated at the occurrence of emergent symptoms or considered at a PAA threshold of >2 cm. The PAAs were divided into small (≤15 mm) and large (>15 mm) aneurysms. The mean surveillance follow-up was 5.1 years.

RESULTS

Most of the 241 identified patients (397 limbs) with a diagnosis of PAAs had bilateral aneurysms (n = 156). Most patients were treated within the study period (163 of 241; 68%), and one half of the diagnosed extremities with PAA had been treated (54%; 215 of 397). Among those who had undergone elective repair, treatment had usually occurred within 1 year after the diagnosis (66%; 105 of 158). More small PAAs were detected in the group that had required emergent repair compared with elective repair (6 of 57 [11%] vs 12 of 158 [8%]; P < .001). No differences were found in the mean diameters between the elective and emergent groups (30.1 mm vs 32.2 mm; P = .39). Growth was recorded in 110 PAAs and on multivariate analysis was associated with a larger index diameter (odds ratio, 1.138; 95% confidence interval, 1.040-1.246; P = .005) and a concurrent abdominal aortic aneurysm (odds ratio, 2.553; 95% confidence interval, 1.018-6.402; P = .046).

CONCLUSIONS

The present cohort of patients represented a true contemporary clinical setting of monitored PAAs and showed that most of these patients will require elective repair, usually within 1 year. The risk of emergent repair is not negligible for patients with smaller diameter PAAs. However, the optimal selection strategy for preventive early repair is still unknown. Future morphologic studies are needed to support the development of individualized surveillance protocols.

Patients with abdominal aortic aneurysm have a high prevalence of popliteal artery aneurysms

Patients with abdominal aortic aneurysms (AAA) are more prone to develop popliteal artery aneurysms (PAA), but the prevalence is not well known. Our aim was to investigate the prevalence of PAA in patients with AAA, and to determine whether a certain risk factor profile is more commonly found in patients with concurrent aneurysms. All AAA patients (ICD code I71.3, I71.4) attending the outpatient clinic at the Karolinska University Hospital between 2011 and 2013 were included in the study cohort ( n=465); 48% (225) had been subjected to an ultrasound or computed tomography scan of their popliteal arteries. In these patients, three definitions of PAA were considered (⩾ 10.5, ⩾ 12, ⩾ 15 mm), although the overall analysis is based on PAA ⩾ 12 mm. The mean age was 70.7 years (SD 7.5), 89% were men, and the mean AAA diameter was 47 mm (SD 14). The prevalence of PAA was 19% ( n=43) by definition ⩾ 12 mm, and 11% ( n=25) with 15 mm. Claudication was more frequently found in AAA patients with PAA than patients without PAA. Sensitivity between clinical examination and radiology was 26%, and the specificity for clinical examination was 90%. In conclusion, owing to the high prevalence of PAA in AAA patients, described by us and others, the low cost and risks associated with ultrasound and the poor sensitivity at clinical examination, all women and men with AAA should undergo one radiological examination of their popliteal arteries.

Popliteal Artery Aneurysm Surgery: The Role of Emergency Setting

The aim of this study was to compare the outcomes of emergent surgery caused by acute complications versus elective surgery of popliteal artery aneurysms (PAAs) and to evaluate the advantages of elective repair related to limb salvage and bypass patency rates. Fifty PAAs were operated on in 40 patients from January 2000 to December 2004. Surgery was elective in 34 cases (68%) and emergent in 16 (32%). Emergent repair was performed because of acute complications. All patients were treated surgically. Early results in terms of limb salvage, primary patency, and assisted patency were assessed. Follow-up consisted of clinical and/or ultrasonographic examinations at 10 days and 1, 3, 6, and 12 months and yearly thereafter. Long-term limb salvage and bypass patency rates were analyzed. The mean follow-up was 17 months. The 1-year limb salvage rate in the elective group was 97.1% versus 56.3% in the emergent group ( P = .0007). The bypass patency rate at 1 year was 94.1% in the elective group versus 66.7% in the emergent group ( P = .03). In this study, the outcomes of the PAA repair were significantly better in the group operated electively and without acute symptoms at presentation compared with the group with acute complications, operated on emergently, especially related to limb salvage and bypass patency rates.

Endovascular treatment of popliteal artery aneurysms

Popliteal artery aneurysms are relatively uncommon but potentially limb-threatening lesions that can thrombose or cause distal embolization. Identification of these aneurysms, especially in patients with abdominal aortic aneurysms, is imperative, and prophylactic treatment with either surgical exclusion and bypass or endoluminal stent grafting is critical to prevent these poor outcomes. Endovascular approaches currently using the Viabahn stent graft offer several advantages, including a minimally invasive approach, fewer perioperative complications, and a faster recovery. This must be balanced with a potentially higher failure rate or requirement for reintervention, although contemporary series report comparable short-term outcomes. We present our approach to the evaluation and diagnosis of popliteal aneurysms, the technical aspects of endovascular popliteal aneurysm repair, and a representative case study.