Adjunctive Utilization of Intravascular Ultrasound in Peripheral Arterial Disease Treatment

BACKGROUND

The utility and benefit of intravascular ultrasound (IVUS) has been well established in coronary interventions, however widespread adoption for peripheral interventions has lagged. The objectives of this review article were to discuss the technical components of IVUS, describe key learning pearls for IVUS utilization, and review the literature describing the clinical outcomes of endovascular peripheral arterial interventions using IVUS.

METHODS

A scoping review of the current literature utilizing Pubmed. Terms used to search the literature included "intravascular ultrasound (IVUS)" in conjunction with "peripheral arterial disease (PAD)," "endovascular interventions," "chronic limb threatening ischemia," "balloon angioplasty" "stenting," "percutaneous coronary intervention," and "outcomes." All types of articles were reviewed including review articles, retrospective reviews, meta-analyses, and prospective observational and randomized studies.

RESULTS

Published literature regarding IVUS use in peripheral arterial interventions is heterogeneous and limited to mainly retrospective studies, registry analyses and metanalyses. Outcomes are generally favorable with the adjunct of IVUS compared to traditional angiography-driven peripheral interventions. The addition of IVUS improves stent expansion, stent patency, and reduces reintervention rates, particularly in infrainguinal arterial lesions. Long-term costs may also be lower with IVUS-guided procedures.

CONCLUSIONS

Expert consensus largely supports the implementation of IVUS in endovascular interventions for peripheral arterial disease. However, more robust high-quality data evaluating the efficacy, durability, and cost of IVUS in peripheral arterial disease are still needed.

Stent-to-vessel diameter ratio is associated with in-stent stenosis after flow-diversion treatment of intracranial aneurysms

BACKGROUND AND PURPOSE

Flow-diversion treatment for intracranial aneurysms has been associated with the development of in-stent stenosis (ISS) for unclear reasons. We assess whether the size of the stent relative to that of the vessel (the stent-to-vessel diameter ratio, or SVR) may be predictive of the development of ISS after treatment with flow diverters.

METHODS

We retrospectively reviewed patients with unruptured intracranial aneurysms who underwent flow-diversion treatment using either the Pipeline or Tubridge embolization device from September 2018 to September 2022. The relationship between SVR and ISS was analyzed. Multiple logistic regression models were used to determine the significant predictors.

RESULTS

A total of 458 patients with 481 aneurysms were included. In a mean angiographic follow-up of 10.73 ± 3.97 months, ISS was detected in 68 cases (14.1 %). After adjusting for candidate variables, a higher distal SVR (DSVR) was associated with an increased risk of ISS (adjusted odds ratio [aOR] = 3.420, 95 % confidence interval [CI] = 1.182 - 9.889, p = 0.023). We conducted a subgroup analysis of the two different flow diverters to assess the effects of their individual characteristics. Our results showed a significant association between the DSVR and the incidence of ISS in both the Pipeline (aOR = 4.033, 95 % CI = 1.156-14.072, p = 0.029) and Tubridge groups (aOR = 11.981, 95 % CI=1.005-142.774, p = 0.049).

CONCLUSION

A higher DSVR was associated with an increased risk of ISS. This may help neurointerventionalists select an appropriate stent size when conducting flow-diversion treatment for intracranial aneurysms.

Impact of Postoperative Lumen Gain on the Reduction of Restenosis Risk after Endovascular Treatment using Drug-coated Balloon for Femoropopliteal Lesions Assessed by Intravascular Ultrasound

AIM

This study aimed to reveal whether a larger postprocedural minimum lumen area (MLA) would reduce restenosis risk after endovascular therapy (EVT) using drug-coated balloons (DCBs) in femoropopliteal (FP) lesions.

METHODS

This retrospective, nonrandomized, single-arm, and multicenter registry analyzed patients with FP lesions undergoing intravascular ultrasound (IVUS)-guided EVT with DCB between 2017 and 2021. The primary outcome was restenosis 1 year after EVT. The association between IVUS-based MLA and restenosis risk was investigated using a generalized propensity score (GPS) method to address imbalance of baseline covariates. The dose-response function of IVUS-measured MLA for restenosis risk was developed using the GPS-adjusted Cox proportional hazards regression model.

RESULTS

This study enrolled consecutive 489 patients with 595 lesions undergoing DCB treatment. The median MLA (interquartile range) was 13.20 (9.90-16.91) mm2. Kaplan-Meier estimates showed that freedom from restenosis was 84.4% at 1 year. The GPS-adjusted dose-response function showed that MLA was inversely associated with restenosis risk. The upper limit of 95% confidence interval (CI) of the slope was lower than 0 between 10.6 and 17.0 mm2 of MLAs. The 1-year cumulative incidence of restenosis was estimated to be 9.8% (95% CI, 5.8%-13.7%) for the 3rd quartile of MLA (16.91 mm2) versus 18.5% (12.3%-24.1%) for the 1st quartile (9.90 mm2), with a hazard ratio of 0.51 (95% CI, 0.39-0.67; p＜0.001).

CONCLUSIONS

The present GPS analysis suggested that larger IVUS-measured MLA might be associated with lower risk of 1-year restenosis after DCB treatment for FP lesions.

Clinical Impact of Intravascular Ultrasound-Guided Fluoropolymer-Based Drug-Eluting Stent Implantation for Femoropopliteal Lesions

BACKGROUND

Treatment with a fluoropolymer-based drug-eluting stent (FP-DES has been widely applied to the contemporary femoropopliteal practice with durable outcomes. Nevertheless, the impact of intravascular ultrasound (IVUS) utilization on clinical outcomes after FP-DES implantation has not been determined.

OBJECTIVES

This study aimed to investigate the impact of IVUS on 1-year clinical outcomes after FP-DES) implantation for femoropopliteal lesions in patients with symptomatic peripheral artery disease.

METHODS

As a subanalysis of the CAPSICUM (contemporary outcomes after paclitaxel-eluting peripheral stent implantation for symptomatic lower limb ischemia with superficial femoral or proximal popliteal lesion) study, the present investigation analyzed 1,091 patients with symptomatic peripheral artery disease who underwent endovascular therapy with FP-DES for femoropopliteal lesions. One-year clinical outcomes were compared between patients treated with IVUS and those treated without IVUS after propensity score matching. The primary outcome measure was 1-year restenosis. The incidence of aneurysmal degeneration was also assessed.

RESULTS

A total of 843 (77.2%) patients underwent IVUS-guided FP-DES implantation. After propensity score matching, the 1-year restenosis was not significantly different between the groups (11.5% [95% CI: 9.1%-14.0%] vs 15.5% [95% CI: 10.9%-20.1%]; P = 0.22). The frequency of aneurysmal degeneration at 1 year was significantly higher in the IVUS group than in the non-IVUS group (19.8% [95% CI: 16.3%-23.4%] vs 7.1% [95% CI: 3.3%-11.0%]; P < 0.001). IVUS use was associated with a lower restenosis risk in patients with chronic total occlusion but not in those without (P for interaction = 0.044).

CONCLUSIONS

The present study revealed that 1-year restenosis risk was not significantly different between the 2 groups, whereas the incidence of aneurysmal degeneration was significantly higher in the IVUS group.

Use of Intravascular Ultrasound During First-Time Femoropopliteal Peripheral Vascular Interventions Among Medicare Beneficiaries

BACKGROUND

Intravascular ultrasound (IVUS) may be a useful adjunct to lower extremity peripheral vascular interventions (PVI) in certain clinical scenarios. We aimed to identify patient- and physician-level characteristics associated with the use of IVUS during first-time femoropopliteal PVI.

METHODS

We included all Medicare beneficiaries undergoing elective femoropopliteal PVI for claudication or chronic limb-threatening ischemia between 01/01/2019 and 12/31/2019. We excluded patients with prior open or endovascular femoropopliteal intervention and all physicians performing ≤10 PVI during the study period. We calculated the proportion of patients who had IVUS performed as part of their index PVI for each physician. Hierarchical logistic regression was used to evaluate patient- and physician-level factors associated with use of IVUS.

RESULTS

We identified 58,552 patients who underwent index femoropopliteal PVI, of whom 11,394 (19%) received IVUS. A total of 1,628 physicians performed >10 procedures during the study period, with IVUS utilization ranging from 0-100%. After hierarchical regression, claudication (versus chronic limb-threatening ischemia: OR 1.23, 95% CI 1.11-1.36), stenting (versus angioplasty alone: OR 1.57, 1.33-1.86) and atherectomy (versus angioplasty alone: OR 2.09, 1.83-2.39) were associated with higher odds of IVUS utilization. Higher-volume providers (tertile 3 vs. tertile 1: OR 3.78, 2.43-5.90) and those with high rates of service provided in an office-based laboratory (tertile 3 vs. tertile 1: OR 10.72, 6.78-19.93) were more likely to utilize IVUS. Radiologists (OR 11.23, 5.96-21.17) and cardiologists (OR 1.97, 1.32-2.93) used IVUS more frequently than vascular surgeons.

CONCLUSIONS

Wide variability exists in the use of IVUS for first-time femoropopliteal PVI. The association of IVUS with claudication, atherectomy, and office-based laboratories raises concern about its potential overuse by some physicians.

Computational analysis of the effects of geometric irregularities on the interaction of an additively manufactured 316L stainless steel stent and a coronary artery

Customized additively manufactured (laser powder bed fused (L-PBF)) stents could improve the treatment of complex lesions by enhancing stent-artery conformity. However, geometric irregularities inherent for L-PBF stents are expected to influence not only their mechanical behavior but also their interaction with the artery. In this study, the influence of geometrical irregularities on stent-artery interaction is evaluated within a numerical framework. Thus, computed arterial stresses induced by a reconstructed L-PBF stent model are compared to those induced by the intended stent model (also representing a stent geometry obtained from conventional manufacturing processes) and a modified CAD stent model that accounts for the increased strut thickness inherent for L-PBF stents. It was found that, similar to conventionally manufactured stents, arterial stresses are initially related to the basic stent design/topology, with the highest stresses occurring at the indentations of the stent struts. Compared to the stent CAD model, the L-PBF stent induces distinctly higher and more maximum volume stresses within the plaque and the arterial wall. In return, the modified CAD model overestimates the arterial stresses induced by the L-PBF stent due to its homogeneously increased strut thickness and thus its homogeneously increased geometric stiffness compared with the L-PBF stent. Therefore, the L-PBF-induced geometric irregularities must be explicitly considered when evaluating the L-PBF stent-induced stresses because the intended stent CAD model underestimates the arterial stresses, whereas the modified CAD model overestimates them. The arterial stresses induced by the L-PBF stent were still within the range of values reported for conventional stents in literature, suggesting that the use of L-PBF stents is conceivable in principle. However, because geometric irregularities, such as protruding features from the stent surface, could potentially damage the artery or lead to premature stent failure, further improvement of L-PBF stents is essential.

Predictive Factors for Restenosis Following Stent-Supported Endovascular Therapy with Intravascular Ultrasound Evaluation for Femoropopliteal Chronic Total Occlusion

PURPOSE

To determine the predictive factors for in-stent restenosis (ISR) following stent-supported endovascular therapy (EVT) with intravascular ultrasound (US) evaluation for femoropopliteal chronic total occlusion.

MATERIALS AND METHODS

This was a single-center, retrospective, observational study. The study included 276 lesions in 251 patients who underwent stent-supported EVT with intravascular ultrasound evaluation for femoropopliteal chronic total occlusion from July 2012 to June 2019. The wire passage route was assessed using intravascular US, and lesions were classified accordingly into 2 groups: intraluminal and subintimal passage. In this study, the intraluminal group was further divided into 3 subgroups by severity of calcification: none, <180°, and ≥180° circumferential. The subintimal group was further divided into 2 subgroups: subintimal passage without or with calcification. The primary outcome measure was ISR. Cox proportional hazards regression was used to determine the association of clinical characteristics with ISR rates.

RESULTS

The mean follow-up period was 19 months ±16, during which time ISR was observed in 31% of lesions. After multivariate analysis, an increased degree of plaque burden (hazard ratio [HR] = 1.101) and subintimal passage with calcification (HR = 3.408) were associated with an increased risk of ISR; a larger distal external elastic membrane area (HR = 0.898) and use of a stent graft (HR = 0.130) were significantly associated with a reduced risk of ISR.

CONCLUSIONS

This study revealed that factors associated with ISR after stent-supported EVT with intravascular US evaluation were distal external elastic membrane area, plaque burden, subintimal passage with calcification, and use of a stent graft.

Open-Label Multicenter Registry on the Outcomes of In-Stent Restenosis Treated by Balloon Angioplasty with Optical Frequency Domain Imaging in the Superficial Femoral Artery (ISLAND-SFA Study)

Objectives: Balloon angioplasty for in-stent restenosis (ISR) in the superficial femoral artery (SFA) has a high recurrent restenosis rate; however, its mechanism has not been fully and precisely evaluated using high-resolution intravascular imaging. Thus, we aimed to evaluate the relationship between vascular features obtained by optical frequency domain imaging (OFDI) and recurrent restenosis at 6 months. Methods: This was a prospective multicenter single-arm study. OFDI was performed before and after balloon angioplasty, and vascular features were assessed. A multi-layered ISR pattern detected by OFDI was defined as several signal-poor appearances with a high-signal band adjacent to the luminal surface. The primary outcome was defined as recurrent restenosis 6 months after balloon angioplasty. Results: Given that this study was terminated early, only 18 patients completed the 6-month follow-up; of these, 8 developed restenosis. Recurrent restenosis at 6 months tended to be related to a multi-layered ISR pattern (odds ratio (OR), 6.67; 95% confidence interval (CI), 0.81-54.96; p=0.078) and the minimum lumen area (MLA) after balloon angioplasty (OR, 0.71; 95%CI, 0.48-1.04; p=0.077). Conclusion: A multi-layered ISR pattern and MLA after balloon angioplasty detected by OFDI might be risk factors for recurrent ISR in the SFA.

Intravascular Ultrasound Imaging During Aortoiliac Stenting: No Impact on Outcomes at 1 Year

PURPOSE

To investigate the effect of intravascular ultrasound (IVUS) imaging use on clinical outcomes after aortoiliac stenting in patients with peripheral artery disease (PAD).

MATERIALS AND METHODS

Subjects for this retrospective analysis were derived from the OMOTENASHI registry database, which contained 803 symptomatic PAD patients (Rutherford categories 2-4) who were treated with self-expanding stent implantation for aortoiliac atherosclerotic lesions at 61 centers in Japan between January 2014 and April 2016. Of the 803 patients, 545 (67.9%) patients (mean age 73±9 years; 453 men) underwent IVUS-supported stent implantation and were compared with the 258 patients (mean age 73±8 years; 217 men) treated without IVUS. A propensity score analysis of 138 matched pairs was conducted to compare treatment strategies and clinical outcomes between patients having IVUS-supported endovascular therapy and those treated without IVUS.

RESULTS

Endovascular strategies and postoperative medications were not significantly different between the IVUS and no-IVUS groups. A procedure time under 1 hour was less frequent in the IVUS group, which had a longer fluoroscopy time. The 12-month restenosis rate was not significantly different between the 2 groups [10.2% (95% CI 6.9 to 14.9%) vs 10.3% (95% CI 5.4 to 18.6%), p=0.99]. There was no interaction between baseline characteristics and the association of IVUS use with restenosis risk.

CONCLUSION

Propensity score matching analysis revealed that duration and fluoroscopy time during IVUS-supported procedures were significantly longer than in cases without IVUS use, whereas the 12-month restenosis rate was not significantly different between the groups. IVUS use in aortoiliac lesions may be unnecessary.

Effectiveness of the Pulsar-18 self-expanding stent with optional drug-coated balloon angioplasty in the treatment of femoropopliteal lesions – the BIOFLEX PEACE All-Comers Registry

Summary. Background: Previous studies showed favorable results after treatment of femoropopliteal lesions with the Pulsar-18 self-expanding (SE) nitinol stent. The objective of this registry was to evaluate whether these results will be confirmed in a real-world setting with varying stenting strategies. Patients and methods: In this prospective, observational trial, 160 patients with 186 femoropopliteal lesions were treated with the Pulsar-18 SE nitinol stent at 9 German sites. Mean lesion length was 116 ± 103 mm, and 41.9 % of the lesions were moderately or heavily calcified. Eighty lesions were concomitantly treated with drug-coated balloon (DCB). Main effectiveness outcome was primary patency at 12 months, and main safety outcome was freedom from the composite of device or procedure related death, major target limb amputation, and clinically driven target lesion revascularization (TLR) at 30 days and 6 months. Results: Kaplan-Meier estimate of primary patency was 89.1 %, 67.3 %, and 57.1 % at 6, 12, and 24 months. Freedom from TLR was 95.5 %, 91.4 %, and 85.2 % at 6, 12, and 24 months, respectively. Lesions, which were additionally treated with DCB (plus DCB-group), were longer (150 versus 82 mm on average, p < 0.0001), and associated with lower primary patency estimates than those without DCB angioplasty (stent-only-group) (log-rank p = 0.006). However, there was no difference in freedom from TLR between groups (log-rank p = 0.542). Improvement by ≥ 1 Rutherford category was achieved in 84.8 %, 81.0 %, and 81.7 % of patients at 6, 12, and 24 months, respectively. Walking distance and patient-reported pain improved persistently through 24 months (p < 0.001). Hemodynamic improvement was achieved in 68.2 %, 73.7 %, and 70.7 % of the patients at 6, 12, and 24 months, respectively. Conclusions: The Pulsar-18 self-expanding nitinol stent with optional drug-coated balloon angioplasty can be considered an efficacious and safe therapy option for endovascular treatment of femoropopliteal artery disease.

Distal Edge Stenosis After Stent Placement for Isolated Superior Mesenteric Artery Dissection: Mechanisms and Risk Factor Analysis

PURPOSE

To analyze factors potentially associated with the occurrence of distal edge stenosis after stent placement for isolated superior mesenteric artery dissection (ISMAD).

MATERIALS AND METHODS

Cases of consecutive patients who were diagnosed with spontaneous ISMAD between February 2010 and July 2018 were retrospectively identified. Of the 123 cases identified, 45 patients (42 men; three women) underwent endovascular stent placement and were included in the study. Univariate and multivariate analyses were used to assess factors potentially associated with distal edge stenosis.

RESULTS

The technical success rate among study patients was 100%. During 26.7 ± 17.3 months of follow-up, CT angiography demonstrated good distal edge patency in 25 patients (55.6%) and evidence of distal edge stenosis in 20 patients (44.4%). In univariate analysis, stent length (odds radio [OR] 1.03; 95% confidence interval [CI] 1.01, 1.06; P = .02), stent-to-vessel (S/V) diameter ratio (OR 2.27; 95% CI 1.35, 3.82; P < .01), and angulation at the distal edge (OR 1.05; 95% CI 1.00, 1.10; P =.03) were significantly associated with distal edge stenosis; only S/V diameter ratio (OR 3.36; 95% CI 1.41, 7.99; P < .01) and angulation at the distal edge (OR 1.12; 95% CI 1.01, 1.23; P =.03) retained this significance in multivariate analysis.

CONCLUSIONS

Distal edge stenosis after stent placement for ISMAD is common. S/V diameter ratio and angulation at the distal edge are independent risk factors for distal edge stenosis in patients with ISMAD who undergo stent placement.