Factors affecting primary patency of stenting for TransAtlantic Inter-Society (TASC II) type B, C, and D iliac occlusive disease

Blood Flow Quantification in Peripheral Arterial Disease: Emerging Diagnostic Techniques in Vascular Surgery

The assessment of local blood flow patterns in patients with peripheral arterial disease is clinically relevant, since these patterns are related to atherosclerotic disease progression and loss of patency in stents placed in peripheral arteries, through mechanisms such as recirculating flow and low wall shear stress (WSS). However, imaging of vascular flow in these patients is technically challenging due to the often complex flow patterns that occur near atherosclerotic lesions. While several flow quantification techniques have been developed that could improve the outcomes of vascular interventions, accurate 2D or 3D blood flow quantification is not yet used in clinical practice. This article provides an overview of several important topics that concern the quantification of blood flow in patients with peripheral arterial disease. The hemodynamic mechanisms involved in the development of atherosclerosis and the current clinical practice in the diagnosis of this disease are discussed, showing the unmet need for improved and validated flow quantification techniques in daily clinical practice. This discussion is followed by a showcase of state-of-the-art blood flow quantification techniques and how these could be used before, during and after treatment of stenotic lesions to improve clinical outcomes. These techniques include novel ultrasound-based methods, Phase-Contrast Magnetic Resonance Imaging (PC-MRI) and Computational Fluid Dynamics (CFD). The last section discusses future perspectives, with advanced (hybrid) imaging techniques and artificial intelligence, including the implementation of these techniques in clinical practice.

Blood Flow Quantification in Peripheral Arterial Disease: Emerging Diagnostic Techniques in Vascular Surgery

The assessment of local blood flow patterns in patients with peripheral arterial disease is clinically relevant, since these patterns are related to atherosclerotic disease progression and loss of patency in stents placed in peripheral arteries, through mechanisms such as recirculating flow and low wall shear stress (WSS). However, imaging of vascular flow in these patients is technically challenging due to the often complex flow patterns that occur near atherosclerotic lesions. While several flow quantification techniques have been developed that could improve the outcomes of vascular interventions, accurate 2D or 3D blood flow quantification is not yet used in clinical practice. This article provides an overview of several important topics that concern the quantification of blood flow in patients with peripheral arterial disease. The hemodynamic mechanisms involved in the development of atherosclerosis and the current clinical practice in the diagnosis of this disease are discussed, showing the unmet need for improved and validated flow quantification techniques in daily clinical practice. This discussion is followed by a showcase of state-of-the-art blood flow quantification techniques and how these could be used before, during and after treatment of stenotic lesions to improve clinical outcomes. These techniques include novel ultrasound-based methods, Phase-Contrast Magnetic Resonance Imaging (PC-MRI) and Computational Fluid Dynamics (CFD). The last section discusses future perspectives, with advanced (hybrid) imaging techniques and artificial intelligence, including the implementation of these techniques in clinical practice.

Covered Stents for Endovascular Treatment of Aortoiliac Occlusive Disease: A Systematic Review and Meta-Analysis

PURPOSE

The treatment of aortoiliac occlusive disease (AIOD) has largely shifted to endovascular techniques, with primary stenting constituting the preferred treatment approach. The goal of the current study was to summarize available literature and to determine whether covered stents are superior to bare metal stents for the treatment of AIOD, in terms of both periprocedural and long-term outcomes.

METHODS

A meta-analysis of 47 studies was conducted with the use of random effects modeling. The incidence of adverse events during follow up among the individual included studies was synthesized.

RESULTS

Most of the lesions were located at the common iliac arteries and were chronic total occlusions. The procedure was technically successful in almost all cases in both groups, with a low rate of periprocedural complications observed in both groups. The reported primary patency rates for the non-covered and covered stent group during an average follow up of 24.3 months among the individual studies, were 84% and 92% respectively, while surgical or endovascular re-intervention was required in 10% of non-covered stent cases and in 6% of covered stent cases. Eight studies comparing covered vs non-covered stents in terms of patency demonstrated superiority of covered stents (OR: 2.47; 95% CI: 1.01-6.01; p = 0.047 Combining TASC C/D lesions together 12 studies reported 92% (95%CI:89%-95%) primary patency in the covered stent group, while 7 studies reported 75% (95%CI: 60%-88%) primary patency for cases treated with non-covered stents.

CONCLUSION

This study demonstrated that covered stents are safe and effective when utilized for the treatment of AIOD. Covered stents were associated with a statistically significant higher odds of primary patency in both the overall cohort and in more complex TASC C/D lesions. However, additional high-quality comparative analyses between covered vs bare metal stents and between several types of covered stents are needed to determine the most optimal treatment modality for AIOD.

Society for Vascular Surgery femoral runoff score is associated with limb-based patency after aortofemoral bypass

OBJECTIVE

Despite advancements, aortofemoral bypass (AFB) remains the most durable option for aortoiliac occlusive disease. Although runoff has been shown to be associated with AFB patency, the association of the Society for Vascular Surgery (SVS) thigh runoff scoring system with patency has not been assessed. The aim of the present study was to evaluate the association between the SVS runoff scoring system and limb-based primary patency after AFB.

METHODS

Institutional data for patients undergoing AFB with preoperative runoff imaging available from 2000 to 2017 were queried. Runoff scores were assigned according to the presence of occlusive disease in the superficial femoral artery and profunda femoris artery (minimum, 1; maximum, 10) as described by the 1997 SVS reporting standards for lower extremity ischemia. Limb-based patency was the primary endpoint. Kaplan-Meier analysis was used to compare the long-term limb-based patency and freedom from reintervention between limbs with runoff scores ≥6 and those with runoff scores <6. Propensity score-weighted Cox proportional hazards modeling was used to evaluate the association between a runoff score of ≥6 and primary patency loss, controlling for other factors associated with primary patency.

RESULTS

In 161 patients, 316 limbs had undergone revascularization. The mean patient age was 66.7 ± 11.3 years, and 51.6% were women. Most limbs had undergone revascularization for claudication (56.5%). Most (89.4%) had TransAtlantic InterSociety Consensus class D lesions, 27.3% had required suprarenal or higher clamping, and 11.2% had undergone concomitant mesenteric intervention. A femoral outflow adjunct and concurrent lower extremity bypass was required in 41.8% and 2.9% of limbs, respectively. Those with a runoff score of ≥6 had experienced greater rates of 30-day myocardial infarction (11% vs 1%; P = .005), respiratory failure (11% vs 1%; P = .005), and mortality (8% vs 0%; P ≤ .006). The median follow-up period was 4.0 years (interquartile range, 6.5 years). The 1-, 3-, and 5-year primary patency was 94.6% (95% confidence interval [CI], 91.9%-97.3%), 89.2% (95% CI, 85.4%-93.2%), and 81.4% (95% CI, 76.0%-87.1%), respectively. The 5-year primary-assisted patency, secondary patency, and freedom from reintervention were 84.9% (95% CI, 79.7%-90.5%), 91.7% (95% CI, 87.3%-96.3%), and 83.3% (95% CI, 78.3%-88.7%), respectively. Patients with a runoff score of ≥6 had lower primary (log-rank P < .01), primary-assisted (P < .01), and secondary patency (P = .01). The factors associated with the loss of primary patency included a high runoff score (runoff score of ≥6: hazard ratio [HR], 4.1; 95% CI, 2.1-8.0; P < .01), simultaneous mesenteric endarterectomy (HR, 13.5; 95% CI, 1.9-97.8; P = .01), and chronic kidney disease (HR, 4.6; 95% CI, 1.5-14.6; P = .01). Increasing age (HR, 0.94 per year; 95% CI, 0.91-0.97; P < .01) and hyperlipidemia (HR, 0.44; 95% CI, 0.23-0.85; P = .01) were protective.

CONCLUSIONS

The SVS femoral runoff score is an important factor associated with long-term AFB limb patency. Scores of ≥6 portend for worse limb outcomes and a greater incidence of operative complications. The SVS score can be determined from preoperative axial imaging studies and serve as a guide in decision-making and operative planning.

Analysis of Preoperative CT Scan Can Help Predict Technical Failure of Endovascular Treatment of TASC C-D Aortoiliac Chronic Total Occlusions

BACKGROUND AND AIMS

To evaluate if features of occlusion analyzable on preoperative computed tomography scan could predict risks of technical failure or iliac rupture of endovascular treatment of TransAtlantic InterSociety Consensus C-D aortoiliac chronic total occlusion.

METHODS AND RESULTS

All patients treated by endovascular techniques for a TransAtlantic InterSociety Consensus C-D aortoiliac chronic total occlusion between 2009 and 2016 were included (107 patients, 148 iliac arteries). We evaluated the location of the occlusion and the importance of the arterial calcifications. For this factor, patients were divided into 3 groups: the Black occlusion group with mild or no calcifications, the white occlusion group with moderate no protrusive calcifications, and the white protrusive occlusion group with heavy endoluminal calcifications. Technical failure occurred in 11 iliac arteries and peroperative iliac rupture in 6. The location in the external iliac artery is the most significate risk factor of technical failure in univariate (OR = 9.93; P = 0.0012) and multivariate analysis (OR = 15.26; P = 0.0006). The presence of heavy endoluminal calcifications is a further significate risk factor (OR = 13.88; P = 0.0365). Rupture rate was comparable between the 3 groups.

CONCLUSIONS

Preoperative computed tomography scan can predict risk of technical failure but not of iliac rupture.

An Endovascular-First Approach for Aortoiliac Occlusive Disease is Safe: Prior Endovascular Intervention is Not Associated with Inferior Outcomes after Aortofemoral Bypass

BACKGROUND

Although prior endovascular intervention is a risk factor for inferior outcomes after infrainguinal bypass, there are few studies evaluating the effect of prior aortoiliac endovascular intervention (AIEI) on outcomes after aortofemoral bypass (AFB). We sought to determine if prior AIEI was predictive of adverse events after AFB.

METHODS

The Vascular Quality Initiative was queried for all patients who underwent AFB form 2009 to 2019. Urgent/emergent cases and repeat procedures were excluded. Primary outcomes were major perioperative complications, major adverse limb event (MALE)-free survival, and long-term survival. Multivariable logistic regression identified predictors of major complications. Predictors of MALE-free survival were identified with Cox proportional hazards modeling.

RESULTS

There were 3,056 patients who underwent AFB; 618 had a prior AIEI. Mean age was 60.3 ± 8.7 years, and 58.7% of patients were men. There was no difference in major complications between the 2 groups (AIEI: 23.8%, no AIEI: 24.5%; P-value = 0.70). Factors associated with major complications were chronic obstructive pulmonary disease (odds ratio [OR]: 1.28, 95% confidence interval [CI]: 1.07-1.54; P = 0.008), simultaneous lower extremity intervention (endarterectomy, bypass, or transluminal intervention, OR 1.41, 95% CI: 1.18-1.69; P < 0.001), congestive heart failure (CHF) (OR 1.58, 95% CI: 1.15-2.16; P = 0.004), increased age (OR 1.03 per year, 95% CI: 1.02-1.04; P < 0.001), increasing operative blood loss (OR 1.35 per liter, 95% CI: 1.21-1.50; P < 0.001), increasing operative time (OR 1.07 per hour, 95% CI: 1.02-1.13; P = 0.008), and end-to-side proximal anastomosis (OR 1.23, 95% CI: 1.03-1.46; P = 0.022). One-year MALE-Free survival was 88.2% (95% CI: 85.2-90.7%) for the prior AIEI group and 89.7% (95% CI: 88.3-90.7%) for the group without prior AIEI (logrank P-value = 0.201). Predictors of MALEs/death were history of a bypass (hazard ratio [HR] 1.51, 95% CI: 1.16-1.96; P = 0.002), increasing degree of ischemia on presentation (HR 1.28 per increasing level of ischemia, 95% CI: 1.16-1.41; P < 0.001), diabetes (HR 1.29, 95% CI: 1.05-1.59; P = 0.014), simultaneous peripheral vascular intervention (HR 2.06, 95% CI: 1.02-4.15; P = 0.044), CHF (HR 1.60, 95% CI: 1.18-2.18; P = 0.002), end-stage renal disease on hemodialysis (HR 5.07, 95% CI: 2.45-10.48; P < 0.001), and presenting hemoglobin<9 g/dl (HR 1.76, 95% CI: 1.02-3.02; P = 0.041). One-year survival for the prior AIEI group was 94.5% (95% CI: 92.2-96.1%) and 94.0% (95% CI: 92.9-94.9%) for the group with no prior AIEI (logrank P = 0.486). Prior AIEI did not predict any of the primary outcomes in multivariable analysis.

CONCLUSIONS

An endovascular-first approach for aortoiliac occlusive disease appears to be safe and does not portend to inferior results after AFB.

Meta-analysis of direct surgical versus endovascular revascularization for aortoiliac occlusive disease

OBJECTIVE

There is a paucity of good-quality evidence comparing direct surgical (DS) with endovascular/hybrid (EVH) revascularization for aortoiliac occlusive disease (AIOD). We aimed to perform a meta-analysis of studies comparing DS and EVH revascularization for AIOD.

METHODS

PubMed, Ovid MEDLINE, Cochrane, and Embase databases were searched for studies comparing DS and EVH revascularization for AIOD from 2000 to 2018. Risk of bias assessment was performed using the Methodological Index for Non-Randomized Studies. Demographics, clinical presentation, and comorbidities of the two groups were compared. Kaplan-Meier curves from selected studies were digitized with WebPlotDigitizer. Meta-analysis was conducted using Review Manager, and outcome measures were compared. Subgroup analysis was performed for primary patency in the EVH group.

RESULTS

Eleven observational studies were identified comparing a sample of 4030 patients. The median Methodological Index for Non-Randomized Studies score was 19 of 24. A total of 1679 and 2351 patients underwent DS and EVH techniques, respectively. No significant difference was found between means for sex, claudication, rest pain, tissue loss, preoperative ankle-brachial pressure index, and TransAtlantic Inter-Society Consensus C and D lesions in the two groups averaged across studies. However, the DS group had significantly younger patients (average age, 61.83 vs 66.77; P = .0011). The risk factors of the two groups, such as smoking, diabetes, ischemic heart disease, hypertension, hyperlipidemia, renal failure, and chronic lung disease, were comparable. Average hospital stay was significantly higher for the DS group (7.76 days vs 3.12 days; P = .025). Change in ankle-brachial pressure index, 30-day mortality, and 30-day graft/stent thrombosis were not significantly different for the groups. Overall, primary patency for a median follow-up of 50 months favored the DS group (hazard ratio [HR], 0.51; confidence interval [CI], 0.36-0.73; P = .0002). There was moderate heterogeneity among studies (I² = 46%). The HR for the subgroup for which endovascular procedures were combined with common femoral endarterectomy was 0.43 compared with 0.88 for endovascular revascularization alone. Limb salvage was similar in both groups (HR, 1.10; CI, 0.74-1.64; P = .63), but overall survival after the procedure favored the DS group (HR, 0.75; CI, 0.60-0.94; P = .01; I² = 0%).

CONCLUSIONS

Moderate-quality studies showed that DS revascularization had significantly better primary patency than EVH revascularization for AIOD, although DS patients were younger and may have differed on other confounding variables. Both techniques had similar limb salvage rates, and the primary patency was better for endovascular revascularization combined with common femoral endarterectomy than for endovascular revascularization alone.

Factors associated with outcome of endovascular treatment of iliac occlusive disease: a single-center experience

Background

Endovascular treatment (ET) of iliac occlusive disease (IOD) is well established in literature. Use of stents in IOD has achieved long-term limb salvage and patency rates similar to those of open surgery, with lower morbidity and mortality rates.

Objectives

To report the long-term outcomes, particularly limb salvage and patency rates, of ET for IOD and the factors associated with these outcomes.

Methods

This retrospective cohort study included patients with IOD who underwent iliac angioplasty (IA), between January 2009 and January 2015. Patients with critical limb ischemia or incapacitating claudication were included.

Results

In total, 48 IA procedures were performed in 46 patients, with an initial technical success rate of 95.83%. Failure occurred in two patients, who were excluded, leaving 44 patients and 46 IA. The primary patency, secondary patency, limb salvage, and survival rates at 1200 days were 88%, 95.3%, 86.3%, and 69.9%, respectively. Univariate and multivariate Cox regression revealed that the primary patency rate was significantly worse in patients with TASC type C/D than in patients with TASC type A/B (p = 0.044). Analysis of factors associated with major amputation using Cox regression showed that the rate of limb loss was greater in patients with TASC type C/D (p = 0.043). Male gender was associated with reduced survival (p = 0.011).

Conclusions

TASC type C/D was associated with a higher number of reinterventions and with worse limb loss and primary patency rates. Male gender was associated with a worse survival rate after ET of IOD.

Influence of Iliac Stenotic Lesions on Blood Flow Patterns Near a Covered Endovascular Reconstruction of the Aortic Bifurcation (CERAB) Stent Configuration

PURPOSE

To investigate the effect of distal stenotic lesions on flow patterns near a covered endovascular reconstruction of the aortic bifurcation (CERAB) configuration used in the treatment of aortoiliac occlusive disease.

METHOD

Laser particle image velocimetry measurements were performed using in vitro models of the aortic bifurcation with and without a CERAB configuration in place. A hemodynamically nonsignificant stenosis (ΔP: 9 mm Hg), a hemodynamically significant (ΔP: 26 mm Hg) stenosis, and a total occlusion were simulated in the left iliac arteries. Velocity fields and time-averaged wall shear stress (TAWSS) were calculated.

RESULTS

Hemodynamically significant distal lesions did not influence the inflow patterns or TAWSS (0.5-0.6 Pa) in either model. However, hemodynamically significant distal stenotic lesions caused a 2-fold decrease in peak outflow velocities (control: 106 vs 56 cm/s, CERAB: 96 vs 54 cm/s) and a 3-fold decrease in TAWSS (control: 1.34 vs 0.44 Pa, CERAB: 0.75 vs 0.21 Pa). There was a 2-fold decrease in wall shear stress in the CERAB outflow compared with the control, independent of lesion severity.

CONCLUSION

In the CERAB technique, adequate distal runoff is identified as an important parameter to ensure patency. This in vitro study showed that distal stenotic lesions influence aortic bifurcation outflow patterns and TAWSS more extensively in the CERAB configuration. Distal stenotic lesions could therefore increase the risk of disease progression and loss of stent patency. In vivo studies are necessary to confirm these observations.

Open and Endovascular Treatment of Trans-Atlantic Inter-Society Consensus II D Aortoiliac Occlusive Lesions: What Determines the Rate of Restenosis?

Background:

Open surgery is the preferred approach for the treatment of type D lesions according to the Trans-Atlantic Inter-Society Consensus (TASC) II guideline, but endovascular solutions also appear to be a valid option in selected patients. The study aimed to identify the risk factors of restenosis after open and endovascular reconstruction of symptomatic TASC II D aortoiliac occlusive lesions (AIOLs).

Methods:

Fifty-six patients (82 limbs) who underwent open repair and endovascular treatment (ET) for symptomatic TASC ΙΙ D AIOLs between March 2005 and December 2012 were retrospectively reviewed. Baseline characteristics, preoperative and postoperative imaging, and operation procedure reports were reviewed and analyzed. Restenosis after revascularization was assessed by duplex ultrasound or computed tomography angiogram. Kaplan-Meier survival analysis, Log-rank test, and multivariate Cox regression were used to evaluate the relevance between risk factors and patency.

Results:

The mean duration of follow-up was 42.8 ± 23.5 months (ranging from 3 to 90 months). Primary patency rates at 1-, 3-, 5-, and 7-year were 93.6%, 89.3%, 87.0%, and 70.3%, respectively. Restenosis after revascularization occurred in 11 limbs. Kaplan-Meier survival analysis and the Log-rank test revealed that diabetes, Rutherford classification ≥5^th and concurrent femoropopliteal TASC II type C/D lesions were significantly related to the duration of primary patency. According to the result of Cox regression, diabetes and femoropopliteal TASC ΙΙ type C/D lesions were identified as the risk factors for restenosis after revascularization.

Conclusion:

This study demonstrated that diabetes and femoropopliteal TASC ΙΙ type C/D lesions are risk factors associated with restenosis after open and ET of TASC II D AIOLs.

The association between periprocedural factors and the late outcome of percutaneous stenting of lower extremity arteries. A retrospective cohort study

Introduction

About 20–30% of the population have peripheral artery disease. Many of them require intervention, with a percutaneous procedure currently being the first choice. However, the outcomes of these interventions need regular evaluation due to continuous progress in endovascular techniques and the devices used.

Aim

The aim of this study was to analyze procedural factors influencing the outcome of endovascular intervention in patients stented for the first time due to lower extremity atherosclerosis.

Material and methods

The medical documentation of 91 patients with at least 1 year of follow-up after stenting of a lower limb artery was retrospectively evaluated. Uni- and multivariate analyses were performed.

Results

The mean observation time was 544.4 ±502.9 days. The primary patency of a stent after such a follow-up was 68.1%. Cox proportional hazard analysis revealed that the risk of target lesion revascularization was affected by the following (hazard risk, 95% confidence interval): the number of vascular segments with significant lesions (13.14, 2.28–75.8); critical limb ischemia (5.68, 1.23–26.2); localization of the target lesion in an aorto-iliac in comparison with a femoro-popliteal vascular segment (0.37, 0.14–0.7); aorto-iliac lesion class according to the TASC-II consensus (1.96, 1.1–3.8); and claudication distance (1.02, 1.01–1.03).

Conclusions

The common primary patency of a stent implanted into either an aorto-iliac or a femoro-popliteal vascular segment was similar to that found in other reports. The main factors affecting the outcome of the endovascular procedures performed were mainly related to atherosclerosis severity, not to the type of technique or device used.