ENDOVASCULAR REPAIR OF POPLITEAL ARTERY ANEURYSMS: TECHNIQUES, CURRENT EVIDENCE AND RECENT EXPERIENCE

Popliteal artery aneurysms treatments: early midterm results of the use of endovascular stent grafts

Background/aim

Popliteal artery aneurysms (PAAs) are abnormal bulgings, which account for 70% of all peripheral artery aneurysms. They are usually asymptomatic. In this study, we present our long-term results of endovascular stent grafts in the treatment of PAA in the light of literature data.

Material and methods

A total of 63 legs of 63 patients with PAA, who were treated with endovascular techniques in our clinic between July 2010 and July 2019, were retrospectively analyzed. All patients underwent color Doppler ultrasound (DUS), magnetic resonance angiography (MRA), or computed tomography angiography (CTA) to identify the diameter and length of PAAs, vessel tortuosity, the presence and degree of thrombus, and diameter in the healthy landing zone and to visualize tibioperoneal vascular structures. A Viabahn stent graft was inserted in all patients.

Results

57 patients (90.5%) were males with a mean age of 76.35 ± 7 years. 24 patients (38.1%) were symptomatic, while 11 patients (17.5%) had a concomitant abdominal aortic aneurysm (AAA). The mean follow-up period was 46.05 ± 25.01 months. The primary patency rate was 79.3%. A graft thrombosis was observed in 13 patients (20.6%) during a mean follow-up period of 8.31 ± 5.91 months. The number of distal arteries was significantly lower in the patients with thrombosis than those without.

Conclusions

Endovascular treatment of PAA using stentgrafts is safe in selected cases. However, it is reasonable to avoid endovascular treatment due to an increased risk for thrombosis in patients with a low number of patent distal arteries or impaired distal flow.

Patient-specific computational fluid dynamics of femoro-popliteal stent-graft thrombosis

Intra-stent thrombosis is one of the major failure modes of popliteal aneurysm endovascular repair, especially when the diseased arterial segment is long and requires overlapping stent-grafts having different nominal diameters in order to accommodate the native arterial tapering. However, the interplay between stent sizing, post-operative arterial tortuosity, luminal diameter, local hemodynamics, and thrombosis onset is not elucidated, yet. In the present study, a popliteal aneurysm was treated with endovascular deployment of two overlapped stent-grafts, showing intra-stent thrombosis at one-year follow-up examination. Patient-specific computational fluid-dynamics analyses including straight- and bent-leg position were performed. The computational fluid-dynamics analysis showed that the overlapping of the stent-grafts induces a severe discontinuity of lumen, dividing the stented artery in two regions: the proximal part, affected by thrombosis, is characterized by larger diameter, low tortuosity, low flow velocity, low helicity, and low wall shear stress; the distal part presents higher tortuosity and smaller lumen diameter promoting higher flow velocity, higher helicity, and higher wall shear stress. Moreover, leg bending induces an overall increase of arterial tortuosity and reduces flow velocity promoting furtherly the luminal area exposed to low wall shear stress.

Two Decades of Endovascular Repair of Popliteal Artery Aneurysm--A Meta-analysis

OBJECTIVE/BACKGROUND

Over the last two decades endovascular repair (EVR) of popliteal artery aneurysms has emerged as a treatment alternative to conventional open surgical repair (OSR). The aim of this review was to evaluate the safety and efficiency of each repair method, comparing the following outcomes after EVR and OSR: (i) primary patency; (ii) operating time; (iii) length of hospital stay; (iv) peri-operative complications; (v) limb salvage; and (vi) patient survival.

METHODS

The PubMed and Cochrane Central Register of Controlled Trials were searched for publications that compared outcomes after EVR and OSR (last search November 2014). Randomized controlled trials (RCTs), prospective and retrospective observational cohort studies were included. The quality of studies was evaluated using the Newcastle-Ottawa scale and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. Random effect models were employed to estimate odds ratios (ORs), mean differences, and hazard ratios (HRs).

RESULTS

One RCT combined with a prospective cohort study and four retrospective cohort studies with an overall total of 652 cases (236 EVR, 416 OSR) were identified. GRADE quality of evidence was low or very low for all outcomes. After a median follow up of 33 months, patients who received EVR showed equal primary patency rates to patients who received OSR (HR 1.46, 95% confidence interval [CI] 0.92-2.33). Lengths of operation and hospitalization were significantly shorter following EVR; rates of 30 day graft thrombosis (OR 3.16, 95% CI 1.31-7.62) and 30 day re-intervention (OR 2.15, 95% CI 1.02-4.55) were significant higher for patients who received EVR compared with those who received OSR. There was no effect on mortality (OR 2.31, 95% CI 0.37-14.49) or limb loss (OR 0.59, 95% CI 0.16-2.15).

CONCLUSION

EVR of popliteal artery aneurysm showed mid-term results comparable to open surgery and appears to be a safe alternative to OSR. However, the existing empirical evidence base is too fragmentary to draw firm conclusions. Further research and the introduction of population based registries will be needed to allow reliable evaluation of EVR.

Acute compartment syndrome related to stent-graft exclusion of a popliteal arterial aneurysm

The purpose of this morbidity and mortality case report is to discuss a characteristic of the Viabahn (W.L. Gore, Newark, DE) stent-graft deployment as well as a complication related to wire trauma during endovascular exclusion of a popliteal artery aneurysm. We encountered a phenomenon not described in the literature during deployment of a Viabahn stent graft. This necessitated further wire purchase, which resulted in perforation of a branch vessel within the calf. The rapid recognition of the clinical findings and prompt diagnosis of compartment syndrome was essential to early intervention, which prevented further complication and permanent sequelae.

Endovascular treatment of peripheral vascular disease

Peripheral arterial disease (PAD) affects about 27 million people in North America and Europe, accounting for up to 413,000 hospitalizations per year with 88,000 hospitalizations involving the lower extremities and 28,000 involving embolectomy or thrombectomy of lower limb arteries. Many patients are asymptomatic and, among symptomatic patients, atypical symptoms are more common than classic claudication. Peripheral arterial disease also correlates strongly with risk of major cardiovascular events, and patients with PAD have a high prevalence of coexistent coronary and cerebrovascular disease. Because the prevalence of PAD increases progressively with age, PAD is a growing clinical problem due to the increasingly aged population in the United States and other developed countries. Until recently, vascular surgical procedures were the only alternative to medical therapy in such patients. Today, endovascular practice, percutaneous transluminal angioplasty with or without stenting, is used far more frequently for all types of lower extremity occlusive lesions, reflecting the continuing advances in imaging techniques, angioplasty equipment, and endovascular expertise. The role of endovascular intervention in the treatment of limb-threatening ischemia is also expanding, and its promise of limb salvage and symptom relief with reduced morbidity and mortality makes percutaneous transluminal angioplasty/stenting an attractive alternative to surgery and, as most endovascular interventions are performed on an outpatient basis, hospital costs are cut considerably. In this monograph we discuss current endovascular intervention for treatment of occlusive PAD, aneurysmal arterial disease, and venous occlusive disease.

Hybrid Approach for Treatment of Behind the Knee Popliteal Artery Aneurysms

We describe herein a combined approach to the treatment of popliteal artery aneurysms (PAA) that averts extensive dissections and potential blood loss particularly in cases of behind-the-knee aneurysms. Over the last 4 years, 13 patients (12 males) with mean age of 75 ± 8 years were treated for PAAs at our institution with a combined surgical and endovascular approach. The mean size of popliteal aneurysms was 2.9 cm ± 1.7 cm. One of the 13 cases (8%) was performed for acute ischemia and an additional 5 (38%) for claudication. All operations were performed under general anesthesia in supine position. Vein conduits (eight ipsilateral great saphenous veins, two contralateral great saphenous veins and one arm vein) were utilized for 11 bypasses. Of these, eight were from superficial femoral artery (SFA) to below the knee popliteal artery, two popliteal to popliteal and one SFA to posterior tibial artery. In addition, two expanded polytetrafluoroethylene femoral popliteal bypasses were performed. The distal anastomosis was performed after the popliteal artery was ligated distal to the aneurysm. Next, coil embolization of the aneurysmal sac was performed under fluoroscopic or ultrasound guidance. Coils were embolized through a 5F sheath. Lastly, the popliteal artery was ligated distal to the proximal anastomosis. Completion studies were obtained with duplex in six cases and arteriography in the remaining five cases. Mean follow-up was 11.6 months ± 9.6. One bypass occluded in 2 months after surgery. One patient demonstrated continued growth of his aneurysm despite coil embolization twice and underwent an open ligation of the branches perfusing the aneurysm from within the sac through a posterior approach. This approach may be particularly useful for PAAs located behind the knee where optimal surgical exposure is often difficult and the collateral circulation is abundant. The proposed technique is simple, effective and averts extensive dissections required to minimize blood loss.

Role of Stents, Drug-Eluting Stents, and Stent-Grafts in Treatment of Infrainguinal Arterial Disease

Infrainguinal peripheral arterial disease is increasingly treatable by endovascular techniques. Bare-metal, drug-eluting, and covered stents (stent-grafts) are increasingly important adjuncts to percutaneous transluminal angioplasty in the treatment of occlusive and aneurysmal disease. Preliminary data suggest bioabsorbable stents may also have a significant clinical impact as well. In this article, we describe the available evidence supporting use of stents in the femoropopliteal and tibial arteries, as well as some of their limitations and complications.

[PTA and stent placement distal to the superficial femoral artery]

Although angioplasty and stent applications in the iliac vessels and the superficial femoral artery have become routine procedures, their usefulness for the treatment of lesions of the popliteal artery and the lower leg arteries is still under discussion. For the popliteal artery, limitations are mainly due to the high mechanical stress in this area, causing high traction forces. Moreover, beyond the occlusive atherosclerotic changes, specific pathological entities such as aneurysms, emboli, entrapment syndromes, and cystic adventitial disease have to be differentiated. There is hope that the development of innovative stent designs with high flexibility might overcome the limitations. For lesions of the lower leg arteries treatment with percutaneous transluminal angioplasty (PTA) has become the method of choice. However, stent designs as used for cardiac interventions have been adapted for their application below the knee, and first encouraging results may help to justify their broad use in the future. Regarding PTA, innovative equipment and techniques for the treatment of arterial lesions below the knee include dedicated, long, and very flexible balloons, cutting balloon cryoplasty, and laser angioplasty. Regarding stents, bare metal stents, stents with passive or active coatings, and bioabsorbable stents have all been successfully used.