Expansion Rates of Asymptomatic Popliteal Artery Aneurysms

Popliteal artery aneurysm ultrasound criteria for reporting characteristics

INTRODUCTION

Duplex ultrasound (DUS) is the modality of choice for surveillance of popliteal artery aneurysms (PAAs). However, noninvasive vascular laboratories have no standard guidelines for reporting results. This study assessed reports of PAA DUS for inclusion of information pertinent to operative decision-making and timing of surveillance.

METHODS

This study was a retrospective review of a multi-institutional repository that was queried for all patients with a PAA from 2008 to 2022 and confirmed via manual chart review. DUS reports were abstracted and images were individually annotated for features of interest including dimensions, flow abnormalities, and percent thrombus burden.

RESULTS

A total of 166 PAAs in 130 patients had at least one DUS available for viewing. Postoperative surveillance of PAAs was performed at several intervals: the first at 30 months (IQR 3.7-113, n = 44), the second at 64 months (IQR 20-172, n = 31), and the third at 152 months (IQR 46-217, n = 16) after the operation. The largest diameter of operative PAAs (median 27.5 mm, IQR 21.8-38.0) was significantly greater than nonoperative PAAs (median 20.9 mm, IQR 16.7-27.3); p < 0.01. Fewer than 33 (21%) reports commented on patency of distal runoff. We calculated an average percent thrombus of 60% (IQR 19-81) in nonoperative PAAs, which is significantly smaller than 75% (IQR 58-89) in operative PAAs; p < 0.01.

CONCLUSION

In this multi-institutional retrospective study, PAAs are often not followed at intervals recommended by the Society for Vascular Surgery guidelines and do not include all measurements necessary for clinical decision-making in the multi-institutional repository studied. There should be standardization of PAA DUS protocols performed by all noninvasive vascular laboratories to ensure completeness of PAA DUS images and inclusion of characteristics pertinent to clinical decision-making in radiology reports.

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.

The Society for Vascular Surgery clinical practice guidelines on popliteal artery aneurysms

The Society for Vascular Surgery clinical practice guidelines on popliteal artery aneurysms (PAAs) leverage the work of a panel of experts chosen by the Society for Vascular Surgery to review the current world literature as it applies to PAAs to extract the most salient, evidence-based recommendations for the treatment of these patients. These guidelines focus on PAA screening, indications for intervention, choice of repair strategy, management of asymptomatic and symptomatic PAAs (including those presenting with acute limb ischemia), and follow-up of both untreated and treated PAAs. They offer long-awaited evidence-based recommendations for physicians taking care of these patients.

Modelling the growth of popliteal artery aneurysms

Background

Popliteal artery aneurysms (PAAs) comprise up to 85 per cent of all peripheral aneurysms. Few longitudinal studies track their progression. This study aimed to track the growth of asymptomatic PAAs in a hospital-based ultrasound service, and compare models of aneurysm growth.

Methods

This retrospective single-centre cohort study included patients who had a PAA on arterial duplex ultrasound imaging of the lower limbs between 1 January 2011 and 1 January 2016. Progression of PAA size and progression to event or intervention were the primary outcome measures.

Results

Some 282 images were analysed: 47 limbs with PAA were included in a cohort of 32 patients (15 had bilateral PAAs). Twenty patients also had an abdominal aortic aneurysm (AAA). Linear multilevel modelling estimated that PAA growth was 2·4 (95 per cent c.i. 1·6 to 3·7) mm a year. Growth was estimated at 0·8 (0·1 to 1·5) mm per year in patients without an AAA and 3·5 (2·9 to 4·2) mm per year in those with a known AAA (previous open repair, previous endovascular aneurysm repair or AAA under surveillance) (P &lt; 0·001).

Conclusion

Growth rates of PAA were heterogeneous but were optimally predicted by multilevel modelling. Patients with an existing AAA may have faster PAA progression than those without.

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.

Update on the Diagnosis and Management of Popliteal Aneurysm and Literature Review

Popliteal artery aneurysms (PAAs) are the most frequent peripheral aneurysm with a significant morbidity if left untreated. Open surgical technique is still considered the gold standard; however the revolution in endovascular repair has proven to be a valid alternative option in selected patients. The role of endovascular treatment in PAA is still considered in its infancy. In addition, the indications for use of endovascular stents as compared to standard open surgery have not yet been fully defined and more studies are warranted to characterize the durability of this technique. This article describes the general principles of the natural history, clinical presentation, and long-term limb salvage and survival outcomes for patients with such aneurysms. It also details the features and results for the devices in current use and highlights the current consensus in the management of PAA.

Update on aneurysm disease: current insights and controversies: peripheral aneurysms: when to intervene - is rupture really a danger?

Peripheral artery aneurysms are rarer than abdominal aortic aneurysms (AAA), although the true prevalence is not well known. They often coexist with aortic and other peripheral artery aneurysms. In contrast to AAA, where the principal risk is that of rupture, thromboembolism is more common, contributing a bigger risk in the more common lesions. Although rupture does occur, with incidence related to anatomical site, aneurysm diameter cannot be used to guide management with the same confidence as in AAA. In addition, the rarity of these lesions results in a paucity of evidence with which to guide intervention. Consequently they are difficult lesions to manage, and numerous aneurysm and patient factors must be considered to provide treatment individualised for each case. We discuss popliteal, femoral, carotid, subclavian, upper limb, visceral and false aneurysms, focussing on the risk of rupture and thromboembolism, and current thresholds for intervention, based on the available published literature.

[Popliteal artery aneurysm: surgical and endovascular therapy]

Aneurysms of the popliteal artery are the most common form of peripheral aneurysm with an incidence of 70-80 %. An enlargement of the popliteal artery of more than 50% of the original diameter is defined as a popliteal artery aneurysm and is found mainly in male patients older than 65 years of age. The incidence is 1%, in 50% of cases is bilateral and in up to 50% in association with other large vessel aneurysms (e.g. abdominal aorta). Differential diagnoses are Baker's cyst, cystic adventitial disease, entrapment syndrome and epitheloid hemangioma. One third of all diagnosed popliteal artery aneurysms are asymptomatic incidental findings, whereas two thirds are conspicuous due to symptoms (acute or chronic ischemia, local compression, rupture). The indications for invasive treatment are given for patients with patent aneurysms at a diameter of more than 2 cm or if a thrombus is present within the aneurysm. Symptomatic popliteal artery aneurysms are always an indication for therapy. Treatment strategies are surgical techniques and endovascular interventions, which both have a similar outcome and graft patency in midterm results.

Nonoperative versus surgical management of small (less than 3 cm), asymptomatic popliteal artery aneurysms

Popliteal artery aneurysms represent a common pathology that vascular surgeons are often confronted with. However, several issues remain incompletely understood, including indications for intervention and optimal methods of treatment. In the following article, our discussants debate the appropriate management of small popliteal artery aneurysms. Further complicating this discussion is the unclear relationship between popliteal artery aneurysm diameter and subsequent complications. Whereas with abdominal aortic aneurysms diameter is linked to rupture risk, it is less clear with popliteal artery aneurysms where complications are more likely to include thrombosis, embolization, and compression whether aneurysm diameter is accurately predictive. Perhaps other anatomic features should be included in our management algorithms? Regardless, our debaters will try to convince us whether small popliteal artery aneurysms warrant repair or not.

Growth and risk factors for expansion of dilated popliteal arteries

OBJECTIVES

The aims of this study were to investigate the change in maximum diameter of ectatic popliteal arteries during ultrasound surveillance and assess clinical predictors of their expansion.

METHODS

Over a ten year period 67 patients with ectasia affecting one (n = 1) or both (n = 66) popliteal arteries entered this surveillance study. Patients were followed for a median of 3.1 years, at a median scan interval of 7.6 months.

RESULTS

Growth of ectatic popliteal arteries was typically slow (<1 mm/yr). Initial artery diameter at entry to the study was not found to be predictive of subsequent growth. Seven patients followed for a median of 2 years had an expansion in popliteal artery diameter to >or=20 mm during follow-up. All of these patients had undergone aneurysm repairs at other arterial sites and none of them had diabetes. These participants also had a significantly higher rate of previous intervention of the contralateral popliteal artery in comparison to those that did not reach the 20 mm threshold (p < 0.001). Growth profiles of arteries that underwent significant expansion during surveillance were frequently characterised by a staccato pattern.

CONCLUSIONS

Expansion of ectatic popliteal arteries is typically slow but difficult to predict. Trends observed in this study suggest that patients with extra-popliteal aneurysms, patients with previously treated contralateral popliteal artery ectasia and those who are not diabetics may be more prone to significant expansion. Further studies are required to validate these potential growth predictors.

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.

Popliteal aneurysms: from John Hunter to the 21st century

Popliteal aneurysms are rare and tend to occur in older men with significant co-morbidity. Historically, management of popliteal aneurysms can be considered in three broad groups: (i) the technique of Antyllus; (ii) techniques relying upon a collateral circulation; and (iii) techniques involving maintenance or restoration of circulation. Bypass and exclusion is currently been challenged by endovascular techniques which show promise in selected cases. Current controversies in popliteal aneurysms management are: when to repair asymptomatic aneurysms, what operation to do and how to manage acute thrombosis. These have been addressed by studying, prospectively, 73 patients presenting with 116 popliteal aneurysms. Diameter greater than 2 cm is often stated as being an indication for elective operation in asymptomatic popliteal aneurysms. However, distortion of the aneurysm appears to be at least as important as size in determining whether symptoms are likely to develop. Of 17 popliteal aneurysms followed for a median of 34 months with a diameter 2-3 cm and distortion less than 45 degrees , none thrombosed. This is no worse than patency following elective bypass (P = 0.064). Popliteal aneurysms greater than 3 cm in diameter in patients who are unfit or who declined an operation were significantly more likely to develop thrombosis or any other symptom (P = 0.01 and P = 0.004, respectively). Popliteal aneurysms less than 3 cm in diameter with distortion less than 45 degrees can safely be managed by ultrasound surveillance. Popliteal aneurysms with greater diameter or distortion are best operated upon. Bypass, combined with proximal and distal ligation of the aneurysm, resulted in 5-year graft patency of 78% and 65% for popliteal aneurysms originally patent or thrombosed, respectively, with good long-term exclusion of the aneurysm. In addition to the general complications of intra-arterial thrombolysis, acute deterioration of the limb during lysis appears to be a particular problem when dealing with thrombosed popliteal aneurysms. It occurs in about 13% of cases which compares with 2% when dealing with thrombosed grafts or native arteries. Intra-arterial thrombolysis for thrombosed popliteal aneurysms is associated with unacceptably high numbers of complications and thrombolysis should be reserved for intra-operative use only.

Early complications and long-term outcome after open surgical treatment of popliteal artery aneurysms: is exclusion with saphenous vein bypass still the gold standard?

BACKGROUND

Popliteal artery aneurysms (PAAs) are rare, but thromboembolic complications may result in limb loss. To define complications and outcomes after open surgical repairs, we reviewed our experience.

METHODS

Clinical data of patients with PAA seen between 1985 and 2004 at Mayo Clinic, Rochester, Minnesota, were reviewed and outcomes in 289 patients with open revascularization were analyzed. Kaplan-Meier method with log-rank tests, chi(2), and Wilcoxon rank sum tests were used for analysis.

RESULTS

A total of 358 PAAs were treated in 289 patients, consisting of 281 (97%) men and eight (3%) women. There were 133 (46%) unilateral and 156 (54%) bilateral PAAs with a mean diameter of 2.9 cm (range, 1.5 to 9 cm). Abdominal aortic aneurysm (AAA) was more frequent with bilateral than unilateral PAAs (65% [101/156] vs 42% [56/133] P = .001). There were 144 (40%) asymptomatic limbs (group 1), 140 (39%) had chronic symptoms (group 2), and 74 (21%) had acute ischemia (group 3). Great saphenous vein (GSV) was used in 242 limbs (68%), polytetrafluoroethylene (PTFE) in 94 (26%), and other types of graft in 22 (6%). Early mortality was 1% (3/358), all in group 3 (4% [3/74]). Six of seven patients with perioperative myocardial infarctions belonged to group 3 (8%). The 30-day graft thrombosis rate was 4%, with 1% in group 1 (1/144), 4% in group 2 (5/140), and 9% in group 3 (7/74). All six early amputations (8%) were in group 3, five with failed bypass (4 PTFE, 1 GSV). Mean follow-up was 4.2 years (range, 1 month to 20.7 years). The 5-year primary and secondary patency rates were 76% and 87%, respectively, higher with GSVs (85% and 94%) than PTFE (50% and 63%, P < .05). Seven recurrent PAAs (2%) required reintervention. The 5-year freedom from reintervention was 100% after endoaneurysmorrhaphy vs 97% after ligations (P = .03). Five-year limb salvage rate was 97% (85% in group 3). There was no limb loss in group 1 and none in group 2 with GSV. In group 3, preoperative thrombolysis reduced the amputation rate in class II patients with marginally threatened limbs (96% vs 69%, P = .02).

CONCLUSION

Acute presentation of PAA continues to carry high mortality and cardiac morbidity; although preoperative thrombolysis appears to improve results, the 8% early and 15% late amputation rates remain ominous. Early elective repair is recommended because these patients had no surgical mortality, a low rate of complications, and asymptomatic patients had no limb loss at 5 years. GSV and endoaneurysmorrhaphy continues to be the gold standard for open repair of PAA.

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.

A Contemporary Review of Popliteal Artery Aneurysms

Popliteal artery aneurysms account for 85% of all peripheral aneurysms and are frequently associated with abdominal aortic aneurysms. Up to 75% of all popliteal artery aneurysms are discovered in symptomatic patients who present with arterial insufficiency, leg swelling, or pain. Popliteal artery aneurysms can be diagnosed with duplex ultrasonography. Aneurysm repair should be considered for all symptomatic patients with rest pain or limb-threatening symptoms. Asymptomatic aneurysms larger than 2 cm should also be treated to prevent the development of limb-threatening ischemia and assure better surgical bypass graft patency and longer freedom from amputation. Conventional aneurysm repair consists of either opening the aneurysm sac and interposing a bypass graft or aneurysm ligation combined with bypass grafting. If the aneurysm sac is left intact, side branch perfusion may persist and the aneurysm may continue to enlarge and can rupture. Endovascular popliteal aneurysm repair has not demonstrated clinical equipoise to standard surgery but may be advantageous in select high-risk patients.

Popliteal aneurysms: controversies in their management

Popliteal artery aneurysms (PAs) occur in older men with significant comorbidity and limited life expectancy. This needs to be remembered when planning elective operation for asymptomatic aneurysms. In the absence of significant distortion PAs <3 cm in diameter can be managed by sequential ultrasound scanning. Their rate of thrombosis is no worse than that of grafts after elective bypass. Intra-arterial thrombolysis for acute thrombosis should be restricted to intra-operative usage to clear run off.