Restenosis after lower extremity interventions: current status and future directions

High-Risk Characteristics for Clinical Failure after Isolated Femoropopliteal Peripheral Vascular Interventions

BACKGROUND

Recent studies suggesting increased late mortality with paclitaxel-coated devices (PCDs) in femoropopliteal peripheral vascular interventions (PVIs) prompted the US Food and Drug Administration to recommend limiting the use of PCDs to "patients at particularly high risk for restenosis". This study's aim is to characterize patients at high risk for restenosis and develop a risk score to guide clinicians in selecting patients for treatment with PCDs.

METHODS

Patients who underwent isolated femoropopliteal PVI for claudication or rest pain from 2016-2019 in the Vascular Quality Initiative were included. Patients who received intervention with a PCD, hybrid procedures, died within 1 year, or had missing follow-up data were excluded. The primary end point was clinical failure at 1 year defined as > 50% restenosis, loss of patency, reintervention, or major amputation. Data were split randomly into 2/3 for development and 1/3 for validation. A parsimonious multivariable hierarchical logistic regression for clinical failure was developed and a risk score was created using beta-coefficients. The risk score was applied to the validation dataset and tested for goodness-of-fit and discrimination.

RESULTS

Among 4,856 treated patients, 718 (14.8%) experienced clinical failure within 1 year. Clinical failure was associated with age ≤ 50 years, female sex (48.1% vs. 39.5%), insulin-dependent diabetes (29.9% vs. 23.1%), creatinine > 2.0 mg/dL (9.9% vs. 5.7%), prior ipsilateral lower extremity revascularization (48.5% vs. 38.5%), prior ipsilateral minor amputation (5.3% vs. 1.7%), rest pain versus claudication (30.8% vs. 18.7%), occlusion length ≥ 20 cm (18.8% vs. 15.0%), and Trans-Atlantic Inter-Society Consensus II Classification C or D (40.4% vs. 28.0%), all P ≤ 0.01. Risk score development was performed using a multivariable regression. The model demonstrated good fit and discrimination (C-statistic 0.71 in development and 0.72 in validation dataset). Predicted clinical failure was 8.9% for standard-risk (45.9% of interventions), 15.5% for high-risk (44.2% of interventions), and 33.8% for very high-risk patients (9.8% of interventions).

CONCLUSIONS

A novel risk score was created with good discrimination for identifying patients at high risk for clinical failure at 1 year after femoropopliteal PVI for claudication and rest pain. Patients at high risk and very high risk for clinical failure may benefit from alternative strategies including PCDs.

Endovascular retrieval of an elongated Supera stent

Stenting is used to achieve artery patency, and the Supera stent, a self-expanding interwoven nitinol stent, has produced good clinical outcomes. A 70-year-old woman with peripheral artery disease had experienced intermittent claudication (Fontaine stage IIb). Endovascular treatment was performed for a chronic total occlusion TransAtlantic InterSociety Consensus class II type B lesion. A Supera stent (Abbott Vascular, Santa Clara, CA) was used. However, it had become severely elongated to the proximal end in the superficial femoral artery and was removed using a balloon inserted from the side and trapped to the guide sheath with the distal end of the stent outside the sheath. After this bailout, an alternate stent could be placed through an antegrade approach to the contralateral common femoral artery.

JetStream Atherectomy for the Treatment of In-Stent Restenosis of the Femoropopliteal Segment: One-Year Results of the JET-ISR Study

PURPOSE

To report the results of a study evaluating JetStream atherectomy for the treatment of in-stent restenosis (ISR).

MATERIALS AND METHODS

The JetStream XC atherectomy device, a rotational cutter with aspiration capacity, was evaluated in a prospective, multicenter study (JET-ISR) of 60 patients (mean age 70.2±10.8 years; 40 men) with femoropopliteal ISR (ClinicalTrials.gov identifier NCT02730234). Lesion length was 19.9±13.5 cm; 33 (55%) were chronic total occlusions and 26 (45%) were TransAtlantic Inter-Society Consensus class D. No drug-bearing device was allowed, and stenting was performed only for bailout. Lesion characteristics and stent integrity were evaluated by an independent core laboratory. The primary endpoint was target lesion revascularization (TLR) at 6 months with bailout stenting considered as TLR. Secondary endpoints included TLR (without bailout stenting) and clinical patency (no restenosis or TLR) at 1 year. The Kaplan-Meier method was employed to evaluate time-to-event endpoints; estimates are given with 95% confidence interval (CI).

RESULTS

Bailout stenting was required in 6 of 60 limbs (10%). There were no stent fractures or deformities after atherectomy + adjunctive angioplasty reported by the core laboratory. Kaplan-Meier estimates of freedom from TLR at 6 months and 1 year were 79.3% (95% CI 68.9% to 89.8%) and 60.7% (95% CI 47.8% to 73.6%), respectively. When bailout stenting at the index procedure was not considered a TLR event, freedom from TLR estimates at 6 months and 1 year were 89.3% (95% CI 81.2% to 97.4%) and 66.8% (95% CI 54.3% to 74.2%), respectively. Clinical patency rates at 6 months and 1 year were 77.5% (31/40) and 51.7% (15/29), respectively.

CONCLUSION

JetStream atherectomy using the XC device and no drug-eluting devices is feasible, with good clinical patency and 1-year freedom from TLR.

Inhibition of ERK or Akt ameliorates intimal hyperplasia via up-regulation of Cx37 and down-regulation of Cx43 in balloon injury rat model

Background

Connexins (Cxs) are reported to participate in atherosclerosis associated intimal hyperplasia (IH), while their function involved in the balloon injury (BI) induced IH and restenosis is less reported.

Methods

Forty-eight male Sprague-Dawley rats were randomly assigned to not injured (NI) group and BI group, which were further administrated with ERK-inhibitor U0216 and Akt-inhibitor MIK2206. Western blot and RT-PCR were utilized to detect the expression of Cx30, Cx37, Cx40, and Cx43 at 6 hours, 24 hours, 7 days, and 14 days post-surgery. H&E staining and related intima area, media area, and luminal area measurement were applied to indicate neointima formation and IH. ERK and Akt phosphorylation levels and proliferating cell nuclear antigen (PCNA) immunostaining were also detected.

Results

Among the four Cxs detected, Cx37 showed down-regulated, and Cx43 showed up-regulated temporal expression pattern in BI rats with confirmed neointima formation. Up-regulated p-ERK (P<0.01) and p-Akt (P<0.01) can be detected in BI rats compared with NI rats. Meanwhile, U0216 and MIK2206 can significantly reduce Cx43 expression and increase CX37 expression accompanied with reduced neointima formation and PCNA staining (P<0.05 or P<0.01) in BI rats.

Conclusions

ERK or Akt inhibition can alleviate BI-induced IH via up-regulation of Cx37 and down-regulation of Cx43.

Photodynamic therapy of balloon-injured rat carotid arteries using indocyanine green

Photodynamic therapy (PDT) has been used to inhibit intimal hyperplasia in injured arteries. Because of the limited tissue penetration of visible light, an endovascular light source with a guided wire is often required for effective treatment. Indocyanine green (ICG), a near-infrared (NIR) photosensitizer, has been used in PDT for cancers. An extracorporeal light source may be used for shallow tissue because of the better tissue penetration of NIR light. The aim of this study was to evaluate the effect of ICG-PDT using extracorporeal NIR light on the inhibition of intimal hyperplasia in balloon-injured carotid arteries. A balloon injury (BI) model was used to induce intimal hyperplasia of carotid artery. Sprague-Dawley rats were divided into control, BI, BI + 1 × PDT, and BI + 2 × PDT groups. The control group underwent a sham procedure. PDT was performed 7 days after BI. In the BI + 1 × PDT group, ICG was administered 1 h before light irradiation. External illumination with 780-nm light-emitting diode light at a fluence of 4 J/cm² was applied. For the BI + 2 × PDT group, PDT was performed again at day 7, following the first PDT. Hematoxylin and eosin (H & E) staining was performed to assess vessel morphology. Arterial wall thickness was significantly larger in the BI group compared with the control group. ICG-PDT significantly reduced arterial wall thickness compared with the BI group. Repeated PDT further decreased arterial wall thickness to the level of the control group. These findings indicate a promising approach for the treatment of restenosis of carotid arteries.

JetStream Rotational and Aspiration Atherectomy in Treating In-Stent Restenosis of the Femoropopliteal Arteries

Purpose: To evaluate the outcomes and stent-device interaction of the JetStream atherectomy device in the treatment of in-stent restenosis (ISR) of the femoropopliteal segment. Methods: The JetStream XC atherectomy device, a rotational cutter with aspiration capacity, was evaluated in a prospective cohort of 29 patients (mean age 69.9±11.7 years; 11 men) with femoropopliteal ISR in 32 limbs ( ClinicalTrials.gov identifier NCT01722877). Lesion length was 17.4±13.1 cm. The primary effectiveness outcome was acute success (≤30% residual narrowing with no serious adverse events). The primary safety endpoint was major adverse events. Secondary endpoints included clinically driven target lesion revascularization (TLR) at 6 months and 1 year and loss of stent integrity as assessed by an angiographic core laboratory. Results: Treated length was 19.5±12.9 cm. Acute success was obtained in 29/32 (91%) limbs. Acute device success (<50% residual narrowing after atherectomy alone) was 76% (22/29). Adjunctive balloon angioplasty was performed in all cases at a mean pressure of 11.6±3.3 atm. Embolic filter protection was used in 16 (50%) of 32 limbs. Macrodebris was noted in 2 (12%) of 16 filters. Distal embolization requiring treatment occurred in 3/32 (9.4%) limbs (2 with no filter). Other non-procedure-related adverse events were 1 (3%) death (nonvascular) and 1 (3%) case of major bleeding. There were no new stent fractures or deformities (n=24) postatherectomy. Follow-up was completed on 27 patients (29 limbs) at 6 and 12 months. TLR at these time points occurred in 4/29 (14%) and 12/29 (41%) patients. Patency (duplex-derived peak systolic velocity ratio <2.4) was 72% at 6 months. Conclusion: JetStream atherectomy using the XC device has favorable acute results in treating femoropopliteal ISR with high procedure success, no device-stent interaction, and favorably low TLR rates. A multicenter trial is needed to confirm these results.

Endovascular brachytherapy and restenosis following lower limb angioplasty: Systematic review and meta-analysis of randomized clinical trials

BACKGROUND

Restenosis is a fundamental weakness of percutaneous femoropopliteal angioplasty (PTA). The potential of endovascular brachytherapy (EVBT) to reduce restenosis has been evaluated in randomized clinical trials, but no pooled analysis has been undertaken.

METHODS

A systematic review was undertaken to identify randomized controlled trials in which PTA alone was compared to PTA plus EVBT. The Pubmed and Medline databases, American Heart Association OASIS database and conference proceedings from the Peripheral Vascular Surgery Society and Vascular Society of Great Britain and Ireland were searched. Eligible studies were randomised controlled trials comparing PTA to PTA plus EVBT in human subjects with at least one clinical outcome reported (restenosis, complications, patency). Study quality was assessed by the Jadad score. Random-effects modeling was used to generate pooled effect size estimates.

RESULTS

Six trials (687 patients) were identified. EVBT reduced 12-month restenosis rates (pooled odds ratio 0.50; 95% CI 0.301-0.836; p=0.008). The benefit disappeared by 24 months. The short-term risk of new lesions elsewhere in the treated artery was significantly increased by EVBT (pooled odds ratio 8.65; 95% CI 2.176-34.391; p=0.002).

CONCLUSIONS

While limited by the small sample sizes in the included trials, this analysis suggests that the early benefit of EVBT is counter-balanced by the increased risk of new lesions and the lack of medium- to long-term reductions in restenosis risk. Based upon the best available evidence, EVBT cannot be recommended for routine clinical use.