Female Sex Portends Increased Risk of Major Amputation Following Surgical Repair of Symptomatic Popliteal Artery Aneurysms

Deciphering Popliteal Artery Aneurysm Patient Diversity: Insights From a Cluster Analysis of the POPART Registry

BACKGROUND

Popliteal artery aneurysms (PAAs) are the most common peripheral aneurysm. However, due to its rarity, the cumulative body of evidence regarding patient patterns, treatment strategies, and perioperative outcomes is limited. This analysis aims to investigate distinct phenotypical patient profiles and associated treatment and outcomes in patients with a PAA by performing an unsupervised clustering analysis of the POPART (Practice of Popliteal Artery Aneurysm Repair and Therapy) registry.

METHODS AND RESULTS

A cluster analysis (using k-means clustering) was performed on data obtained from the multicenter POPART registry (42 centers from Germany and Luxembourg). Sensitivity analyses were conducted to explore validity and stability. Using 2 clusters, patients were primarily separated by the absence or presence of clinical symptoms. Within the cluster of symptomatic patients, the main difference between patients with acute limb ischemia presentation and nonemergency symptomatic patients was PAA diameter. When using 6 clusters, patients were primarily grouped by comorbidities, with patients with acute limb ischemia forming a separate cluster. Despite markedly different risk profiles, perioperative complication rates appeared to be positively associated with the proportion of emergency patients. However, clusters with a higher proportion of patients having any symptoms before treatment experienced a lower rate of perioperative complications.

CONCLUSIONS

The conducted analyses revealed both an insight to the public health reality of PAA care as well as patients with PAA at elevated risk for adverse outcomes. This analysis suggests that the preoperative clinic is a far more crucial adjunct to the patient's preoperative risk assessment than the patient's epidemiological profile by itself.

Sex disparities in popliteal artery aneurysms

OBJECTIVE

Only 5% of patients with popliteal artery aneurysms (PAAs) are female. Evidence on PAA treatment and outcomes in women is therefore scarce. The POPART Registry provides one of Europe's largest data collections regarding PAA treatment. Data on clinical presentation, aneurysm morphology, and perioperative outcomes after open surgical PAA repair in women will be presented.

METHODS

POPART is a multicenter, noninterventional registry for open and endovascular PAA repair, with 42 participating centers in Germany and Luxembourg. All patients aged >18 years who have been treated for PAA since 2010 are eligible for study inclusion. Data collection is based on an online electronic case report form.

RESULTS

Of the 1236 PAAs, 58 (4.8%) were in women. There were no significant differences in age or cardiopulmonary comorbidities. However, female patients had a lower prevalence of contralateral PAAs and abdominal aortic aneurysms (P < .05). PAAs in women were more likely to be symptomatic before surgery (65.5% vs 49.4%; P = .017), with 19% of women presenting with acute limb ischemia (vs 11%; P = .067). Women had smaller aneurysm diameters than men (22.5 mm vs 27 mm; P = .004) and became symptomatic at smaller diameters (20 mm vs 26 mm; P = .002). Only 8.6% of women and 11.6% of men underwent endovascular aneurysm repair (P > .05); therefore, the perioperative outcome analysis focused on open surgical repair. In total, 23.5% of women and 16.9% of men developed perioperative complications (P > .05). There were no differences in major cardiovascular events (P > .05), but women showed a higher incidence of impaired wound healing (15.7% vs 7.2%; P = .05) and major amputation (5.9% vs 1.1%; P = .027). Female sex was significantly associated with the need for nonvascular reinterventions within 30 days after surgery (odds ratio: 2.48, 95% confidence interval: 1.26-4.88), whereas no significant differences in the odds for vascular reinterventions were observed (odds ratio: 1.98, 95% confidence interval: 0.68-5.77). In the multiple logistic regression model, female sex, symptomatic PAAs, poor quality of outflow vessels, and graft material other than vein graft were independently associated with perioperative reinterventions.

CONCLUSIONS

Women have smaller PAAs, are more likely to be symptomatic before treatment, and are more often affected by nonvascular reinterventions in the perioperative course. As our understanding of aneurysmatic diseases in women continues to expand, sex-specific treatment strategies and screening options for women in well-selected cohorts with modified screening protocols should be continuously re-evaluated.

Association Between Conduit Type and Outcomes After Open Repair of Popliteal Artery Aneurysms

INTRODUCTION

Prior studies have demonstrated acceptable midterm outcomes with prosthetic conduits for above-knee bypass for occlusive disease in patients with inadequate segment great saphenous vein (GSV). In this study we aimed to investigate whether this holds true for open repair of popliteal artery aneurysms (PAA).

METHODS

We queried the Vascular Quality Initiative data for patients who underwent open PAA repair (OPAR). We divided the cohort into three groups based on the conduit used: GSV, other autologous veins, or prosthetic graft. Study outcomes included primary patency, freedom from major amputation, amputation-free survival, and overall survival at 1 y. Kaplan-Meier survival estimates, log-rank tests and multivariable Cox regression were used to compare outcomes between study groups.

RESULTS

A total of 4016 patients underwent bypass for PAA from January 2010 to October 2021. The three cohorts were significantly different in many demographic and clinical characteristics. The adjusted odds of postoperative amputation among symptomatic patients were 3-fold higher for prosthetic conduits compared to the GSV (odds ratio, 3.20; 95% CI, 1.72-5.92; P < 0.001). For the 1-y outcomes, the adjusted risk of major amputation was almost 3-fold higher for patients with symptomatic disease undergoing bypass with prosthetic conduits (hazard ratio [HR], 2.97; 95% CI, 1.35-6.52; P = 0.007). When compared with GSV, prosthetic conduits were associated with 96% increased risk of death when used for repair in symptomatic patients (adjusted hazard ratio (aHR), 1.96; 95% CI, 1.29-2.97; P = 0.002) but no significant association with mortality in asymptomatic patients (aHR, 0.83; 95% CI, 0.37-1.87; P = 0.652). When compared with GSV, prosthetic conduits were associated with a 2-fold increased risk of 1-y major amputation or death when used for repair in symptomatic patients (aHR, 2.03; 95% CI, 1.40-2.94; P < 0.001) but no significant association with mortality in asymptomatic patients (aHR, 0.91; 95% CI, 0.42-1.98; P = 0.816). Comparing bypass with other veins to the GSV among patients with symptomatic disease, there was no statistically significant difference in major amputation risk (HR; 2.44; 95% CI, 0.55-10.82; P = 0.242) and no difference in the adjusted risk of all-cause mortality (aHR, 0.77; 95% CI, 0.26-2.44; P = 0.653). There were no differences in the adjusted risk of loss of primary patency comparing other veins to GSV (HR, 1.53; 95% CI, 0.85-2.76; P = 0.154) and prosthetic conduits to GSV (HR, 0.85; 95% CI, 0.57-1.26; P = 0.422).

CONCLUSIONS

This large study shows that among patients undergoing OPAR, 1-y primary patency does not differ between conduit types. However, prosthetic conduits are associated with significantly higher risk of amputation and death compared to GSV among symptomatic patients. Though non-GSV autologous veins are less often used for OPAR, they have comparably acceptable outcomes as GSV.

Apolipoprotein E (ApoE) Rescues the Contractile Smooth Muscle Cell Phenotype in Popliteal Artery Aneurysm Disease

Popliteal artery aneurysm (PAA) is the most frequent peripheral aneurysm, primarily seen in male smokers with a prevalence below 1%. This exploratory study aims to shed light on cellular mechanisms involved in PAA progression. Sixteen human PAA and eight non-aneurysmatic popliteal artery samples, partially from the same patients, were analyzed by immunohistochemistry, fluorescence imaging, Affymetrix mRNA expression profiling, qPCR and OLink proteomics, and compared to atherosclerotic (n = 6) and abdominal aortic aneurysm (AAA) tissue (n = 19). Additionally, primary cell culture of PAA-derived vascular smooth muscle cells (VSMC) was established for modulation and growth analysis. Compared to non-aneurysmatic popliteal arteries, VSMCs lose the contractile phenotype and the cell proliferation rate increases significantly in PAA. Array analysis identified APOE higher expressed in PAA samples, co-localizing with VSMCs. APOE stimulation of primary human PAA VSMCs significantly reduced cell proliferation. Accordingly, contractile VSMC markers were significantly upregulated. A single case of osseous mechanically induced PAA with a non-diseased VSMC profile emphasizes these findings. Carefully concluded, PAA pathogenesis shows similar features to AAA, yet the mechanisms involved might differ. APOE is specifically higher expressed in PAA tissue and could be involved in VSMC phenotype rescue.