Clinical Outcome of Isolated Popliteal Artery Aneurysms Treated with a Heparin-bonded Stent Graft

Bypass Patency and Amputation-Free Survival after Popliteal Aneurysm Exclusion Significantly Depends on Patient Age and Medical Complications: A Detailed Dual-Center Analysis of 395 Consecutive Elective and Emergency Procedures

Background/Objectives: A popliteal artery aneurysm (PAA) is traditionally treated by an open PAA repair (OPAR) with a popliteo-popliteal venous graft interposition. Although excellent outcomes have been reported in elective cases, the results are much worse in cases of emergency presentation or with the necessity of adjunct procedures. This study aimed to identify the risk factors that might decrease amputation-free survival (efficacy endpoint) and lower graft patency (technical endpoint). Patients and Methods: A dual-center retrospective analysis was performed from 2000 to 2021 covering all consecutive PAA repairs stratified for elective vs. emergency repair, considering the patient (i.e., age and comorbidities), PAA (i.e., diameter and tibial runoff vessels), and procedural characteristics (i.e., procedure time, material, and bypass configuration). Descriptive, univariate, and multivariate statistics were used. Results: In 316 patients (69.8 ± 10.5 years), 395 PAAs (mean diameter 31.9 ± 12.9 mm) were operated, 67 as an emergency procedure (6× rupture; 93.8% severe acute limb ischemia). The majority had OPAR (366 procedures). Emergency patients had worse pre- and postoperative tibial runoff, longer procedure times, and more complex reconstructions harboring a variety of adjunct procedures as well as more medical and surgical complications (all p < 0.001). Overall, the in-hospital major amputation rate and mortality rate were 3.6% and 0.8%, respectively. The median follow-up was 49 months. Five-year primary and secondary patency rates were 80% and 94.7%. Patency for venous grafts outperformed alloplastic and composite reconstructions (p < 0.001), but prolonged the average procedure time by 51.4 (24.3-78.6) min (p < 0.001). Amputation-free survival was significantly better after elective procedures (p < 0.001), but only during the early (in-hospital) phase. An increase in patient age and any medical complications were significant negative predictors, regardless of the aneurysm size. Conclusions: A popliteo-popliteal vein interposition remains the gold standard for treatment despite a probably longer procedure time for both elective and emergency PAA repairs. To determine the most effective treatment strategies for older and probably frailer patients, factors such as the aneurysm size and the patient's overall condition should be considered.

Outcomes of popliteal stent-graft placement at the artery hinge point for popliteal artery aneurysm

OBJECTIVES

to assess whether stent-grafts crossing the hinge point (HP) in the popliteal artery are associated with increased complications and decreased patency rates, after endovascular treatment of the popliteal artery aneurysm.

METHODS

This was a single-center, case-control study. Patients were allocated to either the HP group (subjects with stent-grafts crossing the HP) or the control group (subjects with stent-grafts above and/or below the HP) based on stent-graft location in the femoropopliteal artery. HP was defined as the main curve in the popliteal artery in the most acute angle toward the femur that appeared during knee flexion, which was identified by reviewing post-operative angiograms. Independent, blinded reviews were performed for all imaging data. Graft evaluation by CTA or duplex ultrasound was performed at 1, 3, 6, and 12 months and annually thereafter. Outcomes measured included: stent-graft patency, stent-graft fracture, other stent-related complications, and major adverse events, including reintervention, death, amputation, stroke, and myocardial infarction.

RESULTS

A total of 44 limbs treated with placement of heparin-bonded Viabahn endoprostheses were included in this study. Twenty and Twenty Four patients were allocated to the HP group and the control group, respectively. Primary patency rates of the HP group at 1, 2, 3, and 5 years were 84.1±8.4%, 84.1±8.4%, 84.1±8.4%, and 72.1±13.3%, respectively. The primary patency rates of the control group were 87.0±7.0%, 82.4±8.0%, 82.4±8.0%, and 82.4±8.0%, respectively. There was no significant difference between the two groups (P=0.81). No reintervention was performed in the control group. In the HP group, 5 limbs (25.0%) developed endoleak, 3 (15.0%) developed thrombosis, and one (5.0%) developed a stent fracture followed by thrombosis. Thrombosis occurred in 2 limbs (8.3%) of the control group, and stent-graft migration was observed in another 2 cases (8.3%). Neither group demonstrated stent-graft infection or acute popliteal artery embolism. Overall, incidence of stent-related complications were significantly higher in the HP group (P=0.04). Event-free survival rates of the HP group at 1, 2, 3, and 5 years were 75.0±9.7%, 69.6±10.4%, 61.9±11.8%, and 29.0±12.8%, respectively. Corresponding rates in the control group were 79.2±8.3%, 79.2±8.3%, 79.2±8.3%, and 79.2±8.3%, respectively. The difference was not statistically significant between the two groups (P=0.20) CONCLUSIONS: crossing the HP with femoropopliteal artery stent-grafts increased the risk of stent-related complications and reinterventions but did not decrease stent patency or event-free survival.

Real-world data of popliteal artery aneurysm treatment. Analysis of the POPART registry

OBJECTIVE

Popliteal artery aneurysm (PAA) is a rare disease with a prevalence of 0.1-1%. Within the last years, endovascular repair of PAA (ER) has been performed more frequently despite the lack of high-level evidence compared to open surgery (OR). In 2014, the POPART registry was initiated to validate current treatment options in PAA repair.
 METHOD: POPART is a multinational multicenter registry for peri- and postoperative outcome of endovascular and open PAA repair. Data sets are recorded by the online survey tool "SurveyMonkey®". Regular monitoring and plausibility checks of the data sets are performed to ensure reliability. The aim of this study is to present results of the POPART registry, with data of 41 centers.
 RESULTS: From June 2014 to August 2019, a total of 794 cases were recorded in the PAA registry. OR was performed in 662 patients and ER in 106 patients; 23 Patients were treated conservatively. Four of the 106 patients with primary ER underwent conversion to OR. ER patients were significantly older (ER x˜= 71 vs. OR x˜= 67 (p<0.05). There were no other significant differences in demographics or comorbidities and aneurysm morphology between the two groups. 50.3% patients in the OR group were symptomatic; in the ER group 29.2% (p<0.05). Emergency treatment for acute ischemia, critical ischemia or rupture was necessary in 149 patients (22.5%) in the OR group vs. 11 patients (10.3%) in the ER group.
Most frequent complications after surgery were impaired wound healing (OR n=47, 7.1%; ER n=3, 2.8%, p>0.05) and major bleeding (OR n=26, 3.9%; ER n=3, 2.8%, p>0.05). In-hospital length of stay (= 10d [3-65] OR vs. x˜=7d [1-73] ER) was significantly higher in the OR group. Overall patency was 83.2% vs. 44.7% (OR/ER, p<0.005) after 12 months and 74.2% vs. 29.1% (OR/ER, p<0.005) after 24 months. There was a significantly poorer outcome for prosthetic graft compared to autologous vein in the OR group (71.4% vs. 88.1% 12-month primary patency).
 CONCLUSION: 
 In order to evaluate new treatment techniques such as endovascular repair (ER) for PAA, real world data is of essential importance. This analysis of the first results for the POPART registry shows good perioperative results for endovascular treatment of PAA in asymptomatic patients with good outflow vessels. The perioperative complication rate is low and the postoperative hospital stay is shorter than after OR. However, the patency rates after 12 and 24 months are low in the ER group compared to patients treated with open repair. More follow-up data is required for further interpretation; the completion of the data sets in the registry is ongoing.

Four-year outcomes following endovascular repair in patients with traumatic isolated popliteal artery injuries

OBJECTIVE

The effectiveness of endovascular treatment for popliteal arterial injury has not been well-documented. This study was aimed to investigate the midterm outcomes of endovascular repair of traumatic isolated popliteal arterial injury.

METHODS

Medical records of the patients who underwent endovascular repair for traumatic popliteal arterial injuries from January 2012 to February 2020 were reviewed retrospectively. Clinical data including patient demographics, Injury Severity Score, type of injury, classification of acute limb ischemia, concomitant extremity fracture, runoff vessel status, complications, time of endovascular procedure, time interval from injury to blood flow restoration, length of hospital stay, reintervention, and follow-up were collected and analyzed.

RESULTS

Endovascular repair was performed in 46 patients with traumatic popliteal arterial injuries. The mean Injury Severity Score was 15.8 ± 6.2. The overall limb salvage rate was 89.1%. There were 10 penetrating and 36 blunt injuries (78.3%). The initial angiographic findings revealed occlusion in 34 patients (73.9%), pseudoaneurysm in 2 (4.4%), active extravasation in 9 (19.5%), and arteriovenous fistulas in 1 (2.2%). Technical success was achieved in all 46 patients, via antegrade access in 24 patients (52.2%) and concurrent retrograde access in 22 (47.8%). The mean time interval from popliteal artery injury to blood flow restoration was 10.6 ± 4.9 hours and mean operative time was of 54.9 ± 10.0 minutes. The mean follow-up was 36.1 ± 14.5 months. The primary patency rate was 75.3% at 12 months, 61.9% at 24 months, and 55.7% at 48 months. The secondary patency rate was 92.2% at 12 and 24 months and 85.2% at 48 months. A Cox multivariate analysis revealed that single vessel runoff was an independent risk factor for primary patency loss.

CONCLUSIONS

Endovascular repair of an isolated popliteal artery injury may be a safe and effective alternative treatment in select patients, with acceptable midterm outcomes. Single vessel runoff was an independent risk factor for primary patency loss.

Progressive stenosis of a popliteal artery stent graft by laminated thrombus

We present a case of failed popliteal artery aneurysm repair using a Viabahn stent graft (W. L. Gore & Associates, Flagstaff, Ariz) due to laminated thrombus formation. A 75-year-old man presented with a symptomatic popliteal artery aneurysm. He was treated with a Viabahn stent graft. On follow-up, the patient complained of lower extremity claudication, and duplex ultrasound examination showed a focal intrastent stenosis. A computed tomography scan showed a significant stenosis within the stent graft, at the level of the knee joint creases. The patient underwent superficial femoral artery to distal popliteal surgery. This case report aims to expand on the mechanism of stent graft failure in popliteal aneurysms.

Eligibility of Endovascular Repair for Popliteal Artery Aneurysms According the Instructions for Use

BACKGROUND

Popliteal artery aneurysms (PAAs) are the most common peripheral aneurysms. Although rare and often asymptomatic, there is a significant risk of thrombosis, embolism, and limb loss. The aim of this study was to evaluate the eligibility for endovascular repair of patients treated for symptomatic and asymptomatic PAAs in accordance with the instructions for use (IFU).

METHODS

All patients treated for PAA with open surgical repair between the years 2010 and 2017 were analyzed if suitable for endovascular treatment. Preoperative imaging was reviewed for applicability with an interventional radiologist and 2 vascular surgeons. Evaluation was performed in accordance with the following criteria adopted from the IFU of the Gore ® Viabahn stent graft: at least a single-vessel tibial runoff, proximal and distal landing zone more than 2 cm, no large difference in vessel diameter proximal and distal to the aneurysm, no overstenting of significant collaterals necessary, and no inadequate kinking of the artery. The patients were classified in 3 categories: the patient was eligible, endovascular treatment was feasible, and endovascular treatment was not appropriate.

RESULTS

51 patients with 61 symptomatic and asymptomatic PAAs were identified. Forty-five cases were asymptomatic, 11 cases showed clinical symptoms such as claudication, and in 5 cases, the patients presented with acute ischemia. Twenty-four patients were eligible for endovascular intervention, 14 cases were feasible, and in 23 cases, it was not appropriate in accordance with the IFU.

CONCLUSIONS

In this study, more than one-third of the patients with PAA were not eligible for endovascular treatment in accordance with the IFU and another 23 % showed substantial reasons against endovascular treatment. These data suggest that endovascular repair remains a treatment option for selected patients only. Cross-sectional imaging is mandatory for procedure selection.

Point-of-Care Adipose-Derived Stromal Vascular Fraction Cell Isolation and Expanded Polytetrafluoroethylene Graft Sodding

Adipose-derived stromal vascular fraction (SVF) cell populations are being evaluated for numerous clinical applications. The current study evaluated a point-of-care technology, the Tissue Genesis "TGI 1000" Cell Isolation System™, to perform an automated isolation of adipose-derived SVF cells to be used in the fabrication of a tissue-engineered vascular graft in the operating room. A total of seven patients were enrolled in this study and received femoral to tibial expanded polytetrafluoroethylene bypass grafts to treat peripheral arterial disease. Lipoaspiration of fat was performed on five patients, and the fat sample was processed immediately in the automated system in the operating room. The mean processing time, from the point of fat delivery into the instrument to removal of the SVF-containing syringe, was 70 min. The SVF cell population was evaluated for cell yield, cell viability, endotoxin levels, and microbial contamination. Samples of the SVF preparation were further subjected to microbiologic evaluation both microscopically before implantation of the graft and through a microbiologic screening using aerobic and anaerobic culture conditions. Mean cell yield was 1E5 cells per cc of fat, and endotoxin levels were below the FDA recognized standards. All SVF preparations were released for graft preparation, and the intimal surface of 90-cm-long grafts was pressure sodded with cells at a concentration of 2E5 cells/cm². The sodded grafts (n = 5) and control grafts (n = 2) were immediately implanted and graft patency assessed for 1 year. One year patency was 60% for sodded grafts and 50% for control grafts. Automated preparation of autologous adipose-derived SVF cells for immediate use to create cellular linings on vascular grafts is feasible and safe.

Early and mid-term results in the endovascular treatment of popliteal aneurysms with the multilayer flow modulator

Background The endovascular approach became an alternative to open surgical treatment of popliteal artery aneurysm over the last few years. Heparin-bonded stent-grafts have been employed for endovascular popliteal artery aneurysm repair, showing good and stable results. Only few reports about the use of multilayer flow modulator are available in literature, providing small patient series and short follow-up. The aim of this study is to report the outcomes of patients with popliteal artery aneurysm treated with the multilayer flow modulator in three Italian centres. Methods We retrospectively analysed a series of both symptomatic and asymptomatic patients with popliteal artery aneurysm treated with the multilayer flow modulator from 2009 to 2015. Follow-up was undertaken with clinical and contrast-enhanced ultrasound examinations at 1, 6 and 12 months, and yearly thereafter. Computed tomography angiography was performed in selected cases. Primary endpoints were aneurysm sac thrombosis; freedom from sac enlargement and primary, primary-assisted and secondary patency during follow-up. Secondary endpoints were technical success, collateral vessels patency, limb salvage and aneurysm-related complications. Results Twenty-three consecutive patients (19 males, age 72 ± 11) with 25 popliteal artery aneurysms (mean diameter 23 mm ± 1, 3 symptomatic patients) were treated with 40 multilayer flow modulators during the period of the study. Median follow-up was 22.6 ± 16.7 months. Complete aneurysm thrombosis occurred in 92.9% of cases (23/25 cases) at 18 months. Freedom from sac enlargement was 100% (25/25 cases) with 17 cases of aneurysm sac shrinkage (68%). At 1, 6, 12 and 24 months, estimated primary patency was 95.7%, 87.3%, 77% and 70.1%, respectively. At the same intervals, primary-assisted patency was 95.7%, 91.3%, 86% and 86%, respectively, and secondary patency was 100%, 95.7%, 90.3% and 90.3%, respectively. Technical success was 100%. The collateral vessels patency was 72.4%. Limb salvage was 91.4% at 24-month follow-up. One multilayer flow modulator fracture was reported in an asymptomatic patient. Conclusions Multilayer flow modulator seems a feasible and safe solution for endovascular treatment of popliteal artery aneurysms in selected patients.

A Matched Case-Control Study on Open and Endovascular Treatment of Popliteal Artery Aneurysms

Objective:

To compare early and late results of open and endovascular management of popliteal artery aneurysm in a retrospective single-center matched case-control study

Methods:

From 1981 to 2015, 309 consecutive interventions for popliteal artery aneurysm were performed in our institution, in 59 cases with endovascular repair and in 250 cases with open repair. Endovascular repair was preferred in older asymptomatic patients, while open repair was offered more frequently to patients with a thrombosed popliteal artery aneurysm and a poor run-off status. A one-to-one coarsened exact matching on the basis of the baseline demographic, clinical, and anatomical covariates significantly different between the two treatment options was performed and two equivalent groups of 56 endovascular repairs and open repairs were generated. The two groups were compared in terms of perioperative results with χ2 test and of follow-up outcomes with the Kaplan–Meier curves and log-rank test.

Results:

There were no differences between the two groups in terms of perioperative outcomes. Median duration of follow-up was 38 months. Five-year survival rates were 94% in endovascular repair group and 89.5% in open repair group (p = 0.4, log-rank 0.6). Primary patency rates at 1, 3, and 5 years were 81%, 78%, and 72% in endovascular repair group and 82.5%, 80%, and 64% in open repair group (p = 0.8, log-rank 0.01). Freedom from reintervention at 5 years was 65.5% in endovascular repair group and 76% in open repair group (p = 0.2, log-rank 1.2). Secondary patency at 1, 3, and 5 years was 94%, 86%, and 74% in endovascular repair group, and 94%, 89%, and 71% in open repair group, respectively (p = 0.9, log-rank 0.01). The rates of limb preservation at 5 years were 94% in endovascular repair group and 86.4% in open repair group (p = 0.3, log-rank 0.8).

Conclusion:

Open repair and endovascular repair of popliteal artery aneurysms provided in this retrospective single-center experience similar perioperative and follow-up results in equivalent groups of patients.