Percutaneous Therapies for Peripheral Artery Disease

Treatment of an external iliac artery chronic total occlusion using alternate access sites

Background

With the advent of endovascular techniques, alternate sites such as the pedal and radial arteries can now be accessed when treating peripheral arterial disease to reduce procedural complications, shorten recovery time, and improve patient comfort. However, a paucity of literature exists on the availability of support devices that can be utilized during challenging cases.

Case presentation

A 70 year-old female patient presented for evaluation of severe lifestyle-limiting left-sided claudication refractory to maximal medical therapy. Angiography revealed a chronic total occlusion of the left external iliac artery, which was treated successfully by percutaneous intervention via a primary transpedal approach and with the assistance of the Outback® Elite re-entry device. The patient was discharged 2 h after the procedure and reported significant symptom improvement at follow-up.

Conclusion

This case highlights a newly adopted endovascular approach through an alternate access site and illustrates how the Outback® Elite device can be used as an adjunctive tool in the treatment of complex lower-extremity vascular lesions.

Novel, vessel anatomy adjusting drug-coated balloon-Preclinical evaluation in peripheral porcine arteries

BACKGROUND

The diameter of balloons or stents is selected according to the estimated reference vessel diameter and do not adapt to the vessel anatomy. The aim of the present preclinical studies was to investigate a novel, vessel anatomy adjusting hypercompliant drug-coated balloon catheter (HCDCB).

METHODS

Hypercompliant balloon membranes were coated in a constricted state with high drug density. Drug adherence was investigated in vitro, transfer to the porcine peripheral arteries and longitudinal distribution in vivo. In young domestic swine, neointimal proliferation was induced by vessel overstretch and continuous irritation by permanent stents. Uncoated hypercompliant balloons (HCB), and standard uncoated balloons and drug-coated balloons (DCB) served as controls. Efficacy was assessed by angiography, optical coherence tomography (OCT), and histomorphometry.

RESULTS

HCDCB lost 18.0 ± 3.9% of dose during in vitro simulated delivery to the lesion. Drug transfer to the vessel wall was 13.9 ± 6.4% and drug concentration was 1,044 ± 529 ng/mg tissue. Four weeks after treatment, the histomorphometric neointimal area was smaller with HCDCB versus uncoated HCB (2.39 ± 0.55 mm² vs. 3.26 ± 0.72 mm² , p = .038) and area stenosis (OCT) was less (11.6 ± 6.9% vs. 24.7 ± 9.7%, p = .022). No premature death occurred and no in-life clinical symptoms or treatment-associated thrombi were observed.

CONCLUSIONS

HCDCB were found to inhibit excessive neointimal proliferation. Balloon adaption to different vessel diameters and shapes may provide drug-delivery in irregular lumen and facilitate balloon selection.

Follow-up of patients after revascularisation for peripheral arterial diseases: a consensus document from the European Society of Cardiology Working Group on Aorta and Peripheral Vascular Diseases and the European Society for Vascular Surgery

Peripheral arterial diseases comprise different clinical presentations, from cerebrovascular disease down to lower extremity artery disease, from subclinical to disabling symptoms and events. According to clinical presentation, the patient's general condition, anatomical location and extension of lesions, revascularisation may be needed in addition to best medical treatment. The 2017 European Society of Cardiology guidelines in collaboration with the European Society for Vascular Surgery have addressed the indications for revascularisation. While most cases are amenable to either endovascular or surgical revascularisation, maintaining long-term patency is often challenging. Early and late procedural complications, but also local and remote recurrences frequently lead to revascularisation failure. The rationale for surveillance is to propose the accurate implementation of preventive strategies to avoid other cardiovascular events and disease progression and avoid recurrence of symptoms and the need for redo revascularisation. Combined with vascular history and physical examination, duplex ultrasound scanning is the pivotal imaging technique for identifying revascularisation failures. Other non-invasive examinations (ankle and toe brachial index, computed tomography scan, magnetic resonance imaging) at regular intervals can optimise surveillance in specific settings. Currently, optimal revascularisation surveillance programmes are not well defined and systematic reviews addressing long-term results after revascularisation are lacking. We have systematically reviewed the literature addressing follow-up after revascularisation and we propose this consensus document as a complement to the recent guidelines for optimal surveillance of revascularised patients beyond the perioperative period.

Role of Nitric Oxide Carried by Hemoglobin in Cardiovascular Physiology: Developments on a Three-Gas Respiratory Cycle

A continuous supply of oxygen is essential for the survival of multicellular organisms. The understanding of how this supply is regulated in the microvasculature has evolved from viewing erythrocytes (red blood cells [RBCs]) as passive carriers of oxygen to recognizing the complex interplay between Hb (hemoglobin) and oxygen, carbon dioxide, and nitric oxide-the three-gas respiratory cycle-that insures adequate oxygen and nutrient delivery to meet local metabolic demand. In this context, it is blood flow and not blood oxygen content that is the main driver of tissue oxygenation by RBCs. Herein, we review the lines of experimentation that led to this understanding of RBC function; from the foundational understanding of allosteric regulation of oxygen binding in Hb in the stereochemical model of Perutz, to blood flow autoregulation (hypoxic vasodilation governing oxygen delivery) observed by Guyton, to current understanding that centers on S-nitrosylation of Hb (ie, S-nitrosohemoglobin; SNO-Hb) as a purveyor of oxygen-dependent vasodilatory activity. Notably, hypoxic vasodilation is recapitulated by native S-nitrosothiol (SNO)-replete RBCs and by SNO-Hb itself, whereby SNO is released from Hb and RBCs during deoxygenation, in proportion to the degree of Hb deoxygenation, to regulate vessels directly. In addition, we discuss how dysregulation of this system through genetic mutation in Hb or through disease is a common factor in oxygenation pathologies resulting from microcirculatory impairment, including sickle cell disease, ischemic heart disease, and heart failure. We then conclude by identifying potential therapeutic interventions to correct deficits in RBC-mediated vasodilation to improve oxygen delivery-steps toward effective microvasculature-targeted therapies. To the extent that diseases of the heart, lungs, and blood are associated with impaired tissue oxygenation, the development of new therapies based on the three-gas respiratory system have the potential to improve the well-being of millions of patients.

Total IN.PACT drug-coated balloon initiative reporting pooled imaging and propensity-matched cohorts

OBJECTIVE

Randomized controlled trials have shown that drug-coated balloons (DCBs) provide superior results compared with percutaneous transluminal angioplasty (PTA) for the treatment of femoropopliteal artery disease. However, these trials have generally included short lesions, few occlusions, and small sample sizes. The present study was an individual-level pooled analysis of duplex ultrasonography (DUS) core laboratory-adjudicated and clinical events committee-adjudicated IN.PACT Admiral DCB subjects across two randomized controlled trials and two single-arm prospective studies to characterize the safety and effectiveness of DCB compared with PTA.

METHODS

The subjects were treated with DCB (n = 926) or PTA (n = 143). The end points through 12 months included DUS core laboratory-adjudicated primary patency and clinically driven target lesion revascularization (CD-TLR) using Kaplan-Meier estimates and primary safety using proportions. A propensity-matched analysis of DCB (n = 466) to PTA (n = 136) was conducted to address confounders.

RESULTS

At 12 months, DCB compared with PTA had significantly greater primary patency (88.8% vs 53.9%; P < .001), freedom from CD-TLR (94.3% vs 80.2%; P < .001), and better primary safety composite end point (94.1% vs 78.0%; P < .001). After propensity-matched analysis, DCB remained superior to PTA at 12 months for primary patency (90.5% vs 53.8%; P < .001), freedom from CD-TLR (96.9% vs 80.7%; P < .001), and the primary safety composite end point (96.3% vs 78.4%; P < .001). Across multiple prespecified subgroup analyses, including provisional stenting, DCB remained persistently superior to PTA.

CONCLUSIONS

In the largest, DUS core laboratory-adjudicated, multiethnic, pooled DCB series to date, the IN.PACT Admiral DCB demonstrated significantly greater primary patency, freedom from CD-TLR, and better composite safety at 12 months compared with PTA.

An Animal Model of Human Peripheral Arterial Bending and Deformation

BACKGROUND

Designing peripheral arterial stents has proved challenging, as implanted devices will repetitively and unpredictably deform and fatigue during movement. Preclinical testing is often inadequate, given the lack of relevant animal models. The purpose of this study was to test the hypothesis that deformation of the human peripheral vasculature could be qualitatively and quantitatively modeled using an experimental animal.

METHODS

Anteroposterior contrast angiography was performed in domestic Landrace-Yorkshire farm pigs. Images were obtained with the hind limbs naturally extended then repeated, (1) flexed approximately 90° at the hip and knee, (2) overflexed in a nonphysiological fashion. Quantitative vascular angiographic analysis was utilized to measure arterial diameter, length, and deformation. Percent axial arterial compression and bending were assessed.

RESULTS

Eight iliofemoral arteries in four animals were imaged. Mean luminal diameters of the iliac and femoral segments in the neutral position were 5.4 ± 0.5 mm and 4.6 ± 0.5 mm. Hind limb physiologic flexion induced profound arterial compression, 17 ± 8% and 29 ± 6% and bending, 36°±10° and 76° ± 13° within the iliac and femoral segments, respectively. With extreme flexion, the femoral artery could be reliably bent >90°. The observed findings exceeded the deformation observed historically within the human superficial femoral (∼5% compression and 10° bending) and popliteal artery (∼10% compression and 70° bending).

CONCLUSIONS

Significant nonradial deformation of the porcine iliofemoral arteries was observed during manual hind limb flexion and exceeded that typically observed in humans. This model constitutes a "worst case" scenario for testing deformation and fatigue of intravascular devices indicated for the human peripheral vasculature.

SDF-1 plasmid treatment for patients with peripheral artery disease (STOP-PAD): Randomized, double-blind, placebo-controlled clinical trial

The efficacy of biologic therapies in critical limb ischemia (CLI) remains elusive, in part, due to limitations in trial design and patient selection. Using a novel design, we examined the impact of complementing revascularization therapy with intramuscular JVS-100 – a non-viral gene therapy that activates endogenous regenerative repair pathways. In this double-blind, placebo-controlled, Phase 2B trial, we randomized 109 patients with CLI (Rutherford class V or VI) to 8 mg or 16 mg intramuscular injections of placebo versus JVS-100. Patients were eligible if they persistently had reduced forefoot perfusion, by toe–brachial index (TBI) or skin perfusion pressure (SPP), following successful revascularization with angiographic demonstration of tibial arterial flow to the ankle. The primary efficacy end point was a 3-month wound healing score assessed by an independent wound core laboratory. The primary safety end point was major adverse limb events (MALE). Patients’ mean age was 71 years, 33% were women, 79% had diabetes, and 8% had end-stage renal disease. TBI after revascularization was 0.26, 0.27, and 0.26 among the three groups (placebo, 8 mg, and 16 mg injections, respectively). Only 26% of wounds completely healed at 3 months, without any differences between the three groups (26.5%, 26.5%, and 25%, respectively). Similarly, there were no significant changes in TBI at 3 months. Three (2.8%) patients died and two (1.8%) had major amputations. Rates of MALE at 3 months were 8.8%, 20%, and 8.3%, respectively. While safe, JVS-100 failed to improve wound healing or hemodynamic measures at 3 months. Only one-quarter of CLI wounds healed at 3 months despite successful revascularization, highlighting the need for additional research in therapies that can improve microcirculation in these patients. ClinicalTrials.gov Identifier: NCT02544204

Bivalirudin versus heparin in patients undergoing percutaneous peripheral interventions: A systematic review and meta-analysis

Background

Bivalirudin may be an effective alternative anticoagulant to heparin for use in percutaneous peripheral interventions. We aimed to compare the safety and efficacy of bivalirudin versus heparin as the procedural anticoagulant agent in patients undergoing percutaneous peripheral intervention.

Methods

For this meta-analysis and systematic review, we conducted a search in PubMed, Medline, Embase, and Cochrane for all the clinical studies in which bivalirudin was compared to heparin as the procedural anticoagulant in percutaneous peripheral interventions. Outcomes studied included all-cause mortality, all-bleeding, major and minor bleeding, and access site complications.

Results

Eleven studies were included in the analysis, totaling 20,137 patients. There was a significant difference favoring bivalirudin over heparin for all-cause mortality (risk ratio 0.58, 95% CI 0.39–0.87), all-bleeding (risk ratio 0.62, 95% CI 0.50–0.78), major bleeding (risk ratio 0.61, 95% CI 0.39–0.96), minor bleeding (risk ratio 0.66, 95% CI 0.47–0.92), and access site complications (risk ratio 0.66, 95% CI 0.51–0.84). There was no significant difference in peri-procedural need for blood transfusions (risk ratio 0.79, 95% CI 0.57–1.08), myocardial infarction (risk ratio 0.87, 95% CI 0.59–1.28), stroke (risk ratio 0.77, 95% CI 0.59–1.01), intracranial bleeding (risk ratio 0.77, 95% CI 0.29–2.02), or amputations (OR 0.75, 95% CI 0.53–1.05).

Conclusion

Our meta-analysis suggests that bivalirudin use for percutaneous peripheral interventions is associated with lower all-cause mortality, bleeding, and access site complications as compared to heparin. Further large randomized trials are needed to confirm the current results.

Drug Distribution and Basic Pharmacology of Paclitaxel/Resveratrol-Coated Balloon Catheters

Purpose

To experimentally investigate a new homogenously paclitaxel/resveratrol-coated balloon catheter in terms of transport of the coating to the treated tissue and local effects including histology and functional tests.

Methods

Adherence of the coating to the balloon was explored by in vitro simulation of its passage to the lesion. Paclitaxel and resveratrol transfer to the vessel wall was investigated in porcine coronary and peripheral arteries. Matrix-assisted laser desorption/ionization (MALDI) was used for direct microscopic visualization of paclitaxel in arterial tissue. Inhibition of neointimal proliferation and tolerance of complete coating and resveratrol-only coating was investigated in pigs 4 weeks after treatment, and the effect of resveratrol on inflammation and healing after 3 and 7 days.

Results

Drug loss on the way to the lesion was < 10% of dose, while 65 ± 13% was detected at the site of balloon inflation. After treatment similar proportions of drug were detected in coronary and peripheral arteries, i.e., 7.4 ± 4.6% of dose or 125 ± 74 ng/mg tissue. MALDI showed circumferential deposition. Inhibition of neointimal proliferation by paclitaxel/resveratrol coating was significant (p = 0.001) whereas resveratrol-only coating did not inhibit neointimal proliferation. During the first week after treatment of peripheral arteries with resveratrol-only balloons, we observed nominally less inflammation and fibrin deposition along with a significant macrophage reduction and more pronounced re-endothelialization. No safety issues emerged including left ventricular ejection fraction for detection of potential distal embolization after high-dose treatment of coronary arteries.

Conclusions

Paclitaxel/resveratrol-coated balloons were effective and safe in animal studies. Beyond acting as excipient resveratrol may contribute to vascular healing.

Lower extremity bypass and endovascular intervention for critical limb ischemia fail to meet Society for Vascular Surgery's objective performance goals for limb-related outcomes in a contemporary national cohort

OBJECTIVE

In 2009, the Society for Vascular Surgery (SVS) developed objective performance goals (OPGs) to define the therapeutic benchmarks in critical limb ischemia (CLI) based on outcomes from randomized trials of lower extremity bypass (LEB). Current performance relative to these benchmarks in both LEB and infrainguinal endovascular intervention (IEI) remains unknown. The objective of this study was to determine whether LEB and IEI performed for CLI in a contemporary national cohort met OPG 30-day safety thresholds.

METHODS

SVS OPG criteria were applied to 11,043 revascularizations for CLI performed from 2011 to 2015 in the National Surgical Quality Improvement Program (NSQIP) vascular targeted modules. Primary 30-day safety OPGs including major adverse cardiovascular events (MACEs), major adverse limb events (MALEs), and amputation were calculated for the NSQIP LEB (n = 3833) and IEI (n = 3526) cohorts as well as for subgroups at "high anatomic risk" (infrapopliteal revascularization) and "high clinical risk" (age >80 years and tissue loss). These were compared with SVS OPG benchmarks using χ² comparisons.

RESULTS

Compared with the SVS OPG cohort, both the NSQIP LEB and IEI cohorts had fewer patients at high anatomic risk (LEB, 51%; IEI, 27%; SVS OPG, 60%; both P < .0001). The LEB cohort had fewer patients with high clinical risk than the SVS OPG cohort (LEB, 11%; SVS OPG, 16%; P < .0001). The 30-day MALE was significantly higher in the NSQIP LEB (9.0% [8.7%-9.2%]) and IEI (9.7% [9.4%-10.0%]) cohorts compared with the SVS OPG cohort (6.1% [4.7%-9.0%]; both P ≤ .007), including significantly higher rates of amputation. MACE was significantly lower in the NSQIP LEB (4.2% [4.1%-4.3%]) and IEI (3.1% [3.0%-3.2%]) cohorts compared with the SVS OPG cohort (6.1% [4.7%-8.1%]; both P ≤ .013). Among patients at high anatomic risk, 30-day MALE was significantly higher after LEB (9.5% [9.1%-9.8%]) and IEI (11.1% [10.4-11.8%]) compared with the SVS OPG cohort (6.1% [4.2%-8.6%]; P ≤ .002). Among patients with high clinical risk, IEI was associated with lower MACE compared with the SVS OPG cohort, with similar limb-related outcomes.

CONCLUSIONS

In contemporary real-world practice, LEB and IEI for CLI failed to meet SVS OPG limb-related 30-day safety benchmarks for the entire CLI cohort as well as for the patients at high anatomic risk. Additional investigation using SVS OPGs as consistent end points is required to determine why limb-related outcomes after revascularization for CLI remain suboptimal. LEB and IEI surpassed OPG benchmarks for 30-day cardiovascular morbidity and mortality. OPGs for cardiovascular morbidity in patients undergoing revascularization for CLI deserve re-evaluation using contemporary data.

Recent advances in managing vascular occlusions in the cardiac catheterization laboratory

Vascular occlusions continue to be a significant cause of morbidity and mortality. The management of vascular occlusions in patients is complex, requiring specialized expertise in the cardiac catheterization laboratory and from other disciplines. Knowledge of currently available tools at the operator’s disposal is important to optimize the success of these procedures. In this review, we discuss some of the recent advances in recanalization procedures of vascular occlusions and thrombotic lesions in the cardiac catheterization laboratory.

Myocardial injury after endovascular revascularization in critical limb ischemia predicts 1-year mortality: a prospective observational cohort study

BACKGROUND

Patients with critical limb ischemia (CLI) are at increased risk of cardiovascular complications and mortality. To determine (1) incidence of myocardial injury following endovascular revascularization, and (2) relationship between myocardial injury with 1-year mortality and major adverse cardiovascular events (MACE; i.e., composite of myocardial infarction, stroke, and death).

METHODS AND RESULTS

Single-center, prospective cohort study of CLI patients ≥ 45 years of age, who underwent endovascular revascularization with overnight hospitalization. High-sensitive troponins T (hsTnTs) were measured on admission, 3-6 h after endovascular revascularization and the subsequent morning. Myocardial injury after endovascular revascularization was defined as an hsTnT ≥ 14 ng/L with a relative increase ≥ 30% from the baseline value. We also evaluated other myocardial injury hsTnT thresholds (i.e., ≥ 30, ≥ 40, ≥ 60, and ≥ 80 ng/L). 239 consecutive patients (56% male, mean age 71.5 ± 10.1 years) were included; one patient was lost to follow-up. At 1 year, there were 34 deaths (14.2%), and 48 MACE (20.5%). Myocardial injury with the hsTnT threshold of 14 ng/L and relative increase by ≥ 30% from the baseline level occurred in 61 patients (25.5%). Myocardial injury was independently associated with 1-year mortality ([aHR], 2.44; 95% CI 1.18-5.06, for hsTnT ≥ 14 ng/L to aHR, 3.34; 95% CI 1.29-8.65 for hsTnT ≥ 80 ng/L). Myocardial injury was also independently associated with 1-year MACE ([AOR] 2.89; 95% CI 1.41-5.92 for hsTnT ≥ 14 ng/L to AOR, 6.69; 95% CI 2.17-20.68 for hsTnT ≥ 80 ng/L). 85.2% patients who had myocardial injury did not have ischemic clinical symptoms or electrocardiography changes. In sensitive analysis with exclusion of symptomatic patients that developed myocardial injury for the hsTnT ≥ 14 ng/L threshold, both the 1-year mortality (aHR: 2.19; CI 1.02-4.68; p = 0.04), and 1-year MACE (OR 2.25; CI 1.06-4.77; p = 0.036) remained significant.

CONCLUSIONS

Myocardial injury is common following endovascular revascularization for CLI and associated with the risk of 1-year mortality and MACE.

Public Health Impact of the Centers for Medicare and Medicaid Services Decision on Pass-Through Add-On Payments for Drug-Coated Balloons: A Call to Action

On Wednesday, November 1, 2017, the Centers for Medicare and Medicaid Services (CMS) made a public decision to end the transitional pass-through add-on payment for drug-coated balloons beginning January 1, 2018, without creating a new ambulatory payment classification rate for these devices. In this Viewpoint, the authors highlight the disconnect between the CMS's decision not to create a new ambulatory payment classification category for drug-coated balloons despite demonstrated clinical superiority. The authors believe this decision is more in line with a rigid fee-for-service payment system than a value-based system that encourages quality over quantity, and disadvantages both the elderly and the poor. They call on all who advocate for patients with peripheral artery disease to action, encouraging their engagement on CMS decisions regarding payment.