Arterial calcification increases in distal arteries in patients with peripheral arterial disease

Spatial Atlas for Mapping Vascular Microcalcification Using 18F-NaF PET/CT: Application in Hyperphosphatemic Familial Tumoral Calcinosis

BACKGROUND

Vascular calcification causes significant morbidity and occurs frequently in diseases of calcium/phosphate imbalance. Radiolabeled sodium fluoride positron emission tomography/computed tomography has emerged as a sensitive and specific method for detecting and quantifying active microcalcifications. We developed a novel technique to quantify and map total vasculature microcalcification to a common space, allowing simultaneous assessment of global disease burden and precise tracking of site-specific microcalcifications across time and individuals.

METHODS

To develop this technique, 4 patients with hyperphosphatemic familial tumoral calcinosis, a monogenic disorder of FGF23 (fibroblast growth factor-23) deficiency with a high prevalence of vascular calcification, underwent radiolabeled sodium fluoride positron emission tomography/computed tomography imaging. One patient received serial imaging 1 year after treatment with an IL-1 (interleukin-1) antagonist. A radiolabeled sodium fluoride-based microcalcification score, as well as calcification volume, was computed at all perpendicular slices, which were then mapped onto a standardized vascular atlas. Segment-wise mCSmean and mCSmax were computed to compare microcalcification score levels at predefined vascular segments within subjects.

RESULTS

Patients with hyperphosphatemic familial tumoral calcinosis had notable peaks in microcalcification score near the aortic bifurcation and distal femoral arteries, compared with a control subject who had uniform distribution of vascular radiolabeled sodium fluoride uptake. This technique also identified microcalcification in a 17-year-old patient, who had no computed tomography-defined calcification. This technique could not only detect a decrease in microcalcification score throughout the patient treated with an IL-1 antagonist but it also identified anatomic areas that had increased responsiveness while there was no change in computed tomography-defined macrocalcification after treatment.

CONCLUSIONS

This technique affords the ability to visualize spatial patterns of the active microcalcification process in the peripheral vasculature. Further, this technique affords the ability to track microcalcifications at precise locations not only across time but also across subjects. This technique is readily adaptable to other diseases of vascular calcification and may represent a significant advance in the field of vascular biology.

Below-the-Knee Endovascular Revascularization: A Position Statement

Patients with chronic limb-threatening ischemia, the terminal stage of peripheral artery disease, are frequently afflicted by below-the-knee disease. Although all patients should receive guideline-directed medical therapy, restoration of inline flow is oftentimes necessary to avoid limb loss. Proper patient selection and proficiency in endovascular techniques for below-the-knee revascularization are intended to prevent major amputation and promote wound healing. This review, a consensus among an international panel of experienced operators, provides guidance on these challenges from an endovascular perspective and offers techniques to navigate this complex disease process.

A Systematic Review and Meta-analysis of Atherectomy Plus Balloon Angioplasty Versus Balloon Angioplasty Alone for Infrapopliteal Arterial Disease

OBJECTIVE

The article aimed to compare the efficiency and safety of atherectomy plus balloon angioplasty (BA) with BA alone for the treatment of infrapopliteal arterial disease.

METHODS

According to the inclusion and exclusion criteria, PubMed, Embase, and Cochrane Library database were searched for studies comparing atherectomy plus angioplasty and angioplasty alone in treating infrapopliteal artery lesions until November 2022. The endpoints included technical success, primary patency, clinically-driven target lesion revascularization (CD-TLR), periprocedural complications, distal embolization, target limb major amputation, and all-cause mortality.

RESULTS

Ten studies met the requirements of our meta-analysis, including 7723 patients in the atherectomy plus BA group and 2299 patients in the BA alone group. The meta-analysis showed that atherectomy plus BA was associated with reduced CD-TLR (odds ratio [OR]: 0.51, 95% confidence interval [CI]: 0.34, 0.78, p=0.002) and target limb major amputation (OR: 0.43, 95% CI: 0.19, 1.01, p=0.05) at 12-month follow-up. No statistically significant difference was found in technical success, primary patency, periprocedural complications, distal embolization, or all-cause mortality. Subgroup analysis found a higher rate of primary patency at 6 and 12 months (6 months: OR: 2.26, 95% CI: 1.11, 4.60, p=0.02; 12 months: OR: 2.38, 95% CI: 1.16, 4.86, p=0.02), and lower rates of CD-TLR (OR: 0.45, 95% CI: 0.25, 0.82, p=0.009) and target limb major amputation (OR: 0.43, 95% CI: 0.19, 1.01, p=0.05) at 12 months in patients treated with atherectomy plus drug-coated balloon (DCB) but not in patients treated with atherectomy plus plain old balloon angioplasty (POBA).

CONCLUSIONS

This meta-analysis suggests that compared with BA alone, atherectomy plus BA may reduce the need for CD-TLR and the incidence of target limb major amputation at 12-month follow-up in the treatment of infrapopliteal artery occlusive lesions, even though there are no significant advantages in technical success, primary patency, periprocedural complications, distal embolization, or all-cause mortality. To go further, atherectomy plus DCB shows significant benefits in primary patency, CD-TLR, and target limb major amputation rate but atherectomy plus POBA does not'. However, due to the limitations of this article, more randomized controlled trials (RCTs) are needed to confirm these conclusions.

CLINICAL IMPACT

According to our research, atherectomy combined with BA has the advantages of higher primary patency rate, lower CD-TLR and target limb significant amputation rate in treating infrapopliteal artery occlusive lesions, which may replace the current mainstream surgical method ---BA alone. For the clinician, although the surgery may take longer, it will significantly improve the prognosis and quality of life of patients and hold considerable significance for the management of patients with infrapopliteal arterial disease. Based on the characteristics of infrapopliteal artery disease, this study explored the feasibility of atherectomy combined with BA for infrapopliteal artery disease. Moreover, we found that atherectomy combined with DCB had better clinical efficacy, which should be the innovation of this study.

Comparative Analysis of Mortality and Amputation Rates in Patients Undergoing Atherectomy for Infra-Popliteal Peripheral Arterial Disease: Insight From the VQI

INTRODUCTION

Infra-popliteal peripheral arterial disease (IPPAD) poses challenges due to high restenosis and occlusion rates. The BASIL-2 trial demonstrated the superiority of endovascular treatment compared with surgical bypass in patients with IPPAD. However, the association between different endovascular modalities and clinical outcomes has not been conclusive.

HYPOTHESIS

Combining plain old balloon angioplasty (POBA) with atherectomy is associated with improved clinical outcomes compared with POBA alone.

METHODS

Patients who underwent POBA vs POBA+atherectomy for IPPAD from the Vascular Quality Initiative database were identified. To mitigate potential selection bias, we employed propensity score matching (PSM) to balance the distribution of confounding variables for mortality identified on multivariable logistic regression. Subsequently, we compared patient characteristics and long-term outcomes between the 2 treatment groups.

RESULTS

Among patients who underwent endovascular intervention for IPPAD, 19 979 individuals (80.8%) were treated with POBA alone, while 4747 (19.2%) were treated with both POBA+atherectomy after PSM. Propensity score matching ensured minimal differences in baseline characteristics, such as indication for lower extremity revascularization (LER) and history of LER. After PSM, patients receiving POBA+atherectomy experienced higher rates of technical success and lower perioperative complications, such as renal complications and hematoma, compared with POBA alone. During long-term follow-up, patients who underwent atherectomy had lower rates of major amputation and major adverse limb events (MALE) but slightly lower freedom from reintervention. Nonetheless, there were no differences in mortality.

CONCLUSION

Combining POBA with atherectomy appears to be a safe approach in patients with IPPAD, with lower rates of long-term amputation and MALE at the cost of a higher risk of reintervention.

CLINICAL IMPACT

The use of adjunctive atherectomy is associated with improved long-term outcomes in patients with infra-popliteal disease.

Calcification detection on upper extremity arteries: a comparison of ultrasonic and X-ray methods

Background

Vascular calcification (VC) has been observed in patients with hemodialysis, whereas few studies have investigated calcification in the upper extremity vasculature. Both ultrasound and X-ray are used to investigate the calcification of arteries in patients. However, there is a lack of data on the consistency between these two methods. The aim of this study was to investigate the occurrence of VC in the radial and ulnar arteries of hemodialysis patients and investigate the detection consistency in VC between ultrasound and X-ray.

Methods

Ultrasound and X-ray examinations were performed in the radial and ulnar arteries of both the left and right upper extremities of 40 patients on hemodialysis. The calcification status of arteries was evaluated by the calcification index from ultrasound and X-ray respectively. Clinical variables of patients were collected from all the involved patients.

Results

Of the 40 patients, VC was detected in 31 patients by ultrasound, while X-ray detected VC in 22 patients. Compared to ultrasound assessment, X-ray assessment was 73.21% sensitive but only 66.35% specific with a positive predictive value of 53.95% for detecting calcifications in the radial or ulnar artery. The level of agreement between ultrasound and X-ray results was fair. In addition, our data showed that more ulnar arteries had VCs than the corresponding radial arteries.

Conclusion

Ultrasound is more sensitive in detecting the presence of calcified atherosclerotic lesions. Ultrasound and X-ray exhibited fair consistency. Ultrasound screening for upper extremity radial and ulnar arteries in hemodialysis patients may deserve attention to explore its clinical significance.

Intravascular ultrasound guidance for lower extremity arterial and venous interventions

This review details the utility of intravascular ultrasound (IVUS) for the management of peripheral artery and venous disease. The purpose of this document is to provide an update in the use of IVUS in peripheral arterial and venous pathology and demonstrate the use of IVUS as a practical diagnostic imaging procedure to evaluate and treat peripheral vascular disorders. IVUS, a diagnostic tool that relies on sound waves to produce precise images of the vessel being evaluated, was originally introduced to the medical community for the purposes of peripheral artery imaging, though it was quickly adapted for coronary interventions with positive outcomes. The utility of IVUS includes vessel measurement, pre- and post-procedural planning, treatment optimisation, and detection of thrombus, dissection or calcium severity. While angiography remains the standard imaging approach during peripheral intervention, multiple observational studies and small prospective trials have shown that in comparison, IVUS provides more accurate imaging detail, which may improve procedural outcomes. IVUS can also address limitations of angiography, including the need to administer contrast medium and eliminate the ambiguity associated with other forms of imaging. This review provides contemporary examples of where IVUS is being used during peripheral intervention as well as representative imaging to serve as a resource for the practising clinician.

Drug-Eluting Stents

Endovascular revascularization strategies have advanced tremendously over the years and are now often considered first line for treatment of peripheral arterial disease. Drug-eluting stents (DESs) have been developed as one of the tools to overcome the limitations of elastic recoil and neointimal hyperplasia observed with balloon angioplasty and bare metal stents. While these stents have been extremely successful in coronary revascularization, they have not translated as effectively to the peripheral arteries which differ in their unique mechanical environments and differences in vessel and lesion composition. DESs, through their embedded pharmaceutical agent, seek to inhibit vascular smooth muscle cell (VSMC) proliferation and migration. Paclitaxel, sirolimus, and its derivatives (-limus family) achieve VSMC inhibition through unique mechanisms. Several clinical trials have been performed to evaluate the use of DES in the femoropopliteal and infrapopliteal territory and have demonstrated overall decrease in revascularization rates and improved clinical outcomes.

Orbital Atherectomy Prior to Drug-Coated Balloon Angioplasty in Calcified Infrapopliteal Lesions: A Randomized, Multicenter Pilot Study

PURPOSE

Optimal balloon angioplasty for infrapopliteal lesions is often limited by severe calcification, which has been associated with decreased procedural success and lower long-term patency.

MATERIALS AND METHODS

This was a prospective, randomized, multicenter pilot trial that included adult subjects with calcified lesions located from the popliteal segment below the knee (BTK) joint to within 5 cm above the ankle with ≥70% diameter stenosis by angiography. Patients were randomized 1:1 to undergo orbital atherectomy (OA) with adjunctive drug-coated balloon (DCB) angioplasty versus plain balloon angioplasty (BA) and DCB angioplasty (control). The periprocedural and 12 month outcomes of both procedures were compared.

RESULTS

Overall, 66 subjects (OA + DCB = 32 vs control = 34) were included in an intention to treat analysis. Baseline demographics and lesion characteristics were well-balanced. The mean lesion length was 101.3 mm (SD = 72.8 mm) and 78.8 (SD = 61.0 mm) in the OA + DCB and control groups, respectively, with almost all lesions having severe calcification per the Peripheral Academic Research Consortium (PARC) criteria. Chronic total occlusions (CTOs) were present in 43.8% and 35.3% of the patients in the OA + DCB and control groups, respectively. The technical success of OA + DCB versus DCB was 81.8% and 89.2%, respectively, with 3 slow flow/no reflow, 1 perforation, 1 severe dissection occurred in OA + DCB group, and one distal embolization occurred in the control group. The target lesion primary patency rate was numerically higher in the OA + DCB versus control group at 6 (88.2% vs 50.0%, p=0.065) and 12 month follow-up (88.2% vs 54.5%, p=0.076). The 12 month freedom from major adverse events, clinically-driven target lesion revascularization, major amputation, and all-cause mortality rates were similar between both groups.

CONCLUSION

The results of the Orbital Vessel PreparaTIon to MaximIZe Dcb Efficacy in Calcified BTK (OPTIMIZE BTK) pilot study indicated that utilization of OA + DCB is safe for infrapopliteal disease. Further prospective adequately powered studies should investigate the potential benefit of combined OA + DCB for BTK lesions.

Intravascular Lithotripsy for Treatment of Calcified Infrapopliteal Lesions: Results from the Disrupt PAD III Observational Study

PURPOSE

To evaluate the safety and effectiveness of the Shockwave S⁴ intravascular lithotripsy (IVL) catheter in an "all-comers" cohort of patients with calcified infrapopliteal lesions.

MATERIALS AND METHODS

The Disrupt PAD III Observational Study (NCT02923193) is a prospective, nonrandomized, multicenter single-arm study designed to assess the "real-world" acute safety and effectiveness of the Shockwave Peripheral IVL System for the treatment of de novo calcified, stenotic peripheral arteries. Patients were eligible for enrollment if they had claudication or critical limb ischemia (CLI) and at least moderate calcification as assessed by angiography. This subanalysis includes consecutive patients enrolled with angiographic core lab-assessed treatment of infrapopliteal arteries using the Shockwave S⁴ IVL catheter.

RESULTS

From July 2018 to August 2020, 101 patients with 114 calcified infrapopliteal arteries treated with the S⁴ IVL catheter were enrolled at 15 sites in 3 countries. CLI was present in 69.3% of patients. The anterior tibial and tiboperoneal trunk were the most commonly treated vessels with an overall mean reference vessel diameter (RVD) of 3.1±0.8 mm, minimum lumen diameter (MLD) of 0.5±0.6 mm, and a corresponding diameter stenosis of 83.4%±15.8% by core lab assessment. Mean lesion length was 64.7±54.7 mm with moderate to severe calcification in 69.3% of lesions by the Peripheral Academic Research Consortium (PARC) criteria. Adjunctive calcium-modifying technology, defined as scoring or cutting balloon and/or atherectomy, was used in 22.7% of procedures. The average acute gain at the end of the procedure was 2.0±0.7 mm with a residual stenosis <50% achieved in 99.0% of lesions and a mean residual stenosis of 23.3±12.5%. There were no flow-limiting dissection, embolization, slow flow/no-reflow, or abrupt closure events at the end of the procedure.

CONCLUSION

This subanalysis of the PAD III Observational Study represents the largest report to-date of IVL treatment of heavily calcified below-the-knee (BTK) lesions in a "real-world" patient cohort. The use of S⁴ IVL demonstrated consistent acute safety and effectiveness outcomes consistent with prior IVL peripheral studies. These consistent outcomes were achieved with the initial use of the S⁴ IVL catheter for treatment of complex BTK lesions.

Anti-Atherosclerotic Effect of Afrocyclamin A against Vascular Smooth Muscle Cells Is Mediated via p38 MAPK Signaling Pathway

OBJECTIVE

Research suggests that fine particulate matter (PM2.5) contributes to the expansion and development of atherosclerosis. Infiltration and proliferation of vascular smooth muscle cells (VSMCs) from the blood vessel media into the intima, is an important step in the atherosclerosis pathophysiology. Afrocyclamin A, is an oleanane-type triterpene saponin, isolated from Androsace umbellate, which is commonly used in Chinese herbal medicine. In the study, we examined the effect of Afrocyclamin A on PM2.5-induced VSMCs proliferation and scrutinized possible mechanisms of action.

MATERIALS AND METHODS

In the experimental study, counting Kit-8 (CCK-8) assay was used for estimation of VSMCs viability. BrdU immunofluorescence was used for estimation of VSMCs proliferation. The levels of antioxidant parameters such as malonaldehyde (MDA), superoxide dismutase (SOD), and glutathione (GSH); proinflammatory cytokines such as interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α), nitric oxide (NO), endothelin-1 (ET-1), and vascular cell adhesion molecule-1 (VCAM-1), were estimated. The expression of proliferating cell nuclear antigen (PCNA) and phospho-p38 MAPK (p-p38 MAPK) was assessed.

RESULTS

Compared to PM2.5-treated cells, in addition to reducing PM2.5-induced VSMCs proliferation, Afrocyclamin A reduced the expression of PCNA and p-p38 MAPK, down-regulated the level of TNF-α, IL-1β, IL-6, VCAM-1, MDA and ET-1, and up-regulated SOD, GSH and NO level. Furthermore, the anti-proliferative effect of Afrocyclamin A was considerably increased following co-incubation of Afrocyclamin A with SB203580 (p38 MAPK inhibitor) in comparison with Afrocyclamin A-treated cells.

CONCLUSION

Based on the results, we can conclude that Afrocyclamin A might reduce PM2.5-induced VSMCs proliferation via reduction of p38 MAPK signaling pathway.

Advances in Revascularization for Peripheral Artery Disease: Revascularization in PAD

Effective revascularization of the patient with peripheral artery disease is about more than the procedure. The approach to the patient with symptom-limiting intermittent claudication or limb-threatening ischemia begins with understanding the population at risk and variation in clinical presentation. The urgency of revascularization varies significantly by presentation; from patients with intermittent claudication who should undergo structured exercise rehabilitation before revascularization (if needed) to those with acute limb ischemia, a medical emergency, who require revascularization within hours. Recent years have seen the rapid development of new tools including wires, catheters, drug-eluting technology, specialized balloons, and biomimetic stents. Open surgical bypass remains an important option for those with advanced disease. The strategy and techniques employed vary by clinical presentation, lesion location, and lesion severity. There is limited level 1 evidence to guide practice, but factors that determine technical success and anatomic durability are largely understood and incorporated into decision-making. Following revascularization, medical therapy to reduce adverse limb outcomes and a surveillance plan should be put in place. There are many hurdles to overcome to improve the efficacy of lower extremity revascularization, such as restenosis, calcification, microvascular disease, silent embolization, and tools for perfusion assessment. This review highlights the current state of revascularization in peripheral artery disease with an eye toward technologies at the cusp, which may significantly impact current practice.

Three-Year Outcomes of Orbital Atherectomy for the Endovascular Treatment of Infrainguinal Claudication or Chronic Limb-Threatening Ischemia

Purpose: To investigate the outcomes of orbital atherectomy (OA) for the treatment of patients with peripheral artery disease (PAD) manifesting as claudication or chronic limb-threatening ischemia (CLTI). Materials and Methods: The database from the LIBERTY study (ClinicalTrials.gov identifier NCT01855412) was interrogated to identify 503 PAD patients treated with any commercially available endovascular devices and adjunctive OA for 617 femoropopliteal and/or infrapopliteal lesions. Cox regression analyses were employed to examine the association between baseline Rutherford category (RC) stratified as RC 2-3 (n=214), RC 4-5 (n=233), or RC 6 (n=56) and all-cause mortality, target vessel revascularization (TVR), major amputation, major adverse event (MAE), and major amputation/death at up to 3 years of follow-up. The mean lesion lengths were 78.7±73.7, 131.4±119.0, and 95.2±83.9 mm, respectively, for the 3 groups. Results: After OA, balloon angioplasty was used in >98% of cases, with bailout stenting necessary in 2.0%, 2.8%, and 0% of the RC groups, respectively. A small proportion (10.8%) of patients developed angiographic complications, without differences based on presentation. During the 3-year follow-up, claudicants were at lower risk for MAE, death, and major amputation/death than patients with CLTI. The 3-year Kaplan-Meier survival estimates were 84.6% for the RC 2-3 group, 76.2% for the RC 4-5 group, and 63.7% for the RC 6 group. The 3-year freedom from major amputation was estimated as 100%, 95.3%, and 88.6%, respectively. Among CLTI patients only, the RC at baseline was correlated with the combined outcome of major amputation/death, whereas RC classification did not affect TVR, MAE, major amputation, or death rates. Conclusion: Peripheral artery angioplasty with adjunctive OA in patients with CLTI or claudication is safe and associated with low major amputation rates after 3 years of follow-up. These results demonstrate the utility of OA for patients across the spectrum of PAD.

Balloon Angioplasty of Infrapopliteal Arteries: A Systematic Review and Proposed Algorithm for Optimal Endovascular Therapy

Endovascular revascularization has been increasingly utilized to treat patients with chronic limb-threatening ischemia (CLTI), particularly atherosclerotic disease in the infrapopliteal arteries. Lesions of the infrapopliteal arteries are the result of 2 different etiologies: medial calcification and intimal atheromatous plaque. Although several devices are available for endovascular treatment of infrapopliteal lesions, balloon angioplasty still comprises the mainstay of therapy due to a lack of purpose-built devices. The mechanism of balloon angioplasty consists of adventitial stretching, medial necrosis, and dissection or plaque fracture. In many cases, the diffuse nature of infrapopliteal disease and plaque complexity may lead to dissection, recoil, and early restenosis. Optimal balloon angioplasty requires careful attention to assessment of vessel calcification, appropriate vessel sizing, and the use of long balloons with prolonged inflation times, as outlined in a treatment algorithm based on this systematic review. Further development of specific devices for this arterial segment are warranted, including devices for preventing recoil (eg, dedicated atherectomy devices), treating dissections (eg, tacks, stents), and preventing neointimal hyperplasia (eg, novel drug delivery techniques and drug-eluting stents). Further understanding of infrapopliteal disease, along with the development of new technologies, will help optimize the durability of endovascular interventions and ultimately improve the limb-related outcomes of patients with CLTI.

Current developments in endovascular therapy of peripheral vascular disease

More than 200 million people worldwide have peripheral artery disease (PAD) or its most severe manifestation, critical limb ischemia (CLI). While endovascular treatment has become first line therapy in most cases, a number of challenges remain for optimal treatment of femoropopliteal (FP) or infrapopliteal (IP) disease, especially when these lesions are severely calcified, chronic total occlusions (CTOs) or in-stent restenosis (ISR). Continued evolution of technologies has significantly improved the outcomes for endovascular treatment. A number of new devices are in the pipeline right now, including new paclitaxel eluting stents and balloons, intravascular lithotripsy to treat severely calcified lesions, adventitial delivery of anti-restenotic agents to limit restenosis rates, and percutaneous femoro-popliteal bypass.

Current Role of Atherectomy for Treatment of Femoropopliteal and Infrapopliteal Disease

Atherectomy improves the acute procedural success of a procedure whether treating de novo or restenotic (including in-stent) disease. Intermediate follow-up results seem to be in favor of atherectomy in delaying and reducing the need for repeat revascularization in patients with femoropopliteal in-stent restenosis. Recent data suggest that avoiding cutting into the external elastic lamina is an important factor in reducing restenosis. The interplay between directional atherectomy and drug-coated balloons is unclear.

Novel developments in non-invasive imaging of peripheral arterial disease with CT: experience with state-of-the-art, ultra-high-resolution CT and subtraction imaging

Despite advances, challenges remain for less invasive imaging of peripheral arterial occlusive disease (PAOD) using computed tomography (CT) angiography. The application of dual-energy imaging to PAOD has been reported to improve the diagnostic accuracy of this application; however, severe arteriosclerosis with heavy arterial wall calcification still hampers definitive lesion characterisation, especially in distal and smaller arteries. Recently an ultra-high resolution scanner has been introduced. In combination with advances in post-processing, such as subtraction techniques, these developments may overcome some of the current challenges and allow far more detailed characterisation of PAOD non-invasively. The aim of this review is to describe our current experience with ultra-high resolution CT in combination with subtraction and discuss the potential advantages of their application for peripheral angiography.

Risk factors for unplanned readmission and stump complications after major lower extremity amputation

OBJECTIVE

The unplanned 30-day readmission rate is a marker of quality of patient care across many disciplines. Data regarding risk factors for unplanned readmission after major lower extremity amputation (LEA) are limited. We evaluated predictors of readmission at our institution after major LEA.

METHODS

We conducted a retrospective review of all patients undergoing above-knee amputation (AKA) or below-knee amputation (BKA) between November 2009 and November 2014. Patient demographic variables were collected. Predictors of unplanned 30-day readmission and stump complications were determined by multivariable logistic regression.

RESULTS

A total of 811 patients were identified (AKA, 325; BKA, 486). Of these, 739 patients were included in the final analysis after excluding 30-day decedents without readmission. The overall 30-day readmission rate was 28.8% (AKA 27.9%; BKA 29.4%; P = .730). Stump complications accounted for 28.6% of readmissions (16.5% of AKA; 35.8% of BKA; P = .004). Other common diagnoses included nonsurgical site infection (33.8%), exacerbation of congestive heart failure (7.0%), and diabetes-related complications (6.1%). Surgical intervention was performed on 61% of stump complications (35.9% of AKA readmitted with stump complications; 68.7% of BKA readmitted with stump complications). BKA stump complications were converted to AKAs in 34.1% of cases (3.2% of the total BKA). None of the AKA stump complications required a higher level of amputation (ie, hip disarticulation). Independent predictors of all 30-day readmission included coronary artery disease and end-stage renal disease. American Society of Anesthesiologists class 3 as compared with class 4 was protective. Independent predictors of 30-day readmission for stump complications included rest pain and BKA. Patients who underwent BKA, rest pain as an indication for amputation, and having an occluded bypass graft were predictors of having a stump complication requiring surgery.

CONCLUSIONS

The 30-day readmission rate after major LEA is high, with wound infections accounting for a significant proportion of these readmissions. There was no difference in readmission rates based on level of amputation. Those undergoing BKA were more likely to present with stump complications requiring a surgical intervention, and often a higher level of amputation. Identification of high-risk patients may play a role in reducing postoperative readmissions and stump complications.

Emerging and Future Therapeutic Options for Femoropopliteal and Infrapopliteal Endovascular Intervention

Despite recent advances in endovascular therapy for peripheral artery disease, current technologies remain limited by rates of long-term restenosis and application to complex lesion subsets. This article presents data on upcoming therapies, including novel drug-coated balloons, drug-eluting stents, bioresorbable scaffolds, novel drug delivery therapies to target arteries, techniques to limit postangioplasty dissection, and treatment of severely calcified lesions.

The LargPAD Trial: Phase IIA evaluation of l-arginine infusion in patients with peripheral arterial disease

OBJECTIVE

Endothelial function is improved by l-arginine (l-arg) supplementation in preclinical and clinical studies of mildly diseased vasculature; however, endothelial function and responsiveness to l-arg in severely diseased arteries is not known. Our objective was to evaluate the acute effects of catheter-directed l-arg delivery in patients with chronic lower extremity ischemia secondary to peripheral arterial disease.

METHODS

The study enrolled 22 patients (45% male) with peripheral arterial disease (mean age, 62 years) requiring lower extremity angiography. Endothelium-dependent relaxation of patent but atherosclerotic superficial femoral arteries was measured using a combination of intravascular ultrasound (IVUS) imaging and a Doppler FloWire (Volcano Corporation, Rancho Cordova, Calif) during the infusion of incremental acetylcholine (10^-6 to 10^-4 molar concentration) doses. Patients received 50 mg (n = 3), 100 mg (n = 10), or 500 mg (n = 9) l-arg intra-arterially, followed by repeat endothelium-dependent relaxation measurement (limb volumetric flow). IVUS-derived virtual histology of the culprit vessel was also obtained. Endothelium-independent relaxation was measured using a nitroglycerin infusion. Levels of nitrogen oxides and arginine metabolites were measured by chemiluminescence and mass spectrometry, respectively.

RESULTS

Patients tolerated limb l-arg infusion well. Serum arginine and ornithine levels increased by 43.6% ± 13.0% and 23.2% ± 10.3%, respectively (P < .005), and serum nitrogen oxides increased by 85% (P < .0001) after l-arg infusion. Average vessel area increased by 6.8% ± 1.3% with l-arg infusion (acetylcholine 10^-4; P < .0001). Limb volumetric flow increased in all patients and was greater with l-arg supplementation by 130.9 ± 17.6, 136.9 ± 18.6, and 172.1 ± 24.8 mL/min, respectively, for each cohort. Maximal effects were seen with l-arg at 100 mg (32.8%). Arterial smooth muscle responsiveness to nitroglycerin was intact in all vessels (endothelium-independent relaxation, 137% ± 28% volume flow increase). IVUS-derived virtual histology indicated plaque volume was 14 ± 1.3 mm³/cm, and plaque stratification revealed a predominantly fibrous morphology (46.4%; necrotic core, 28.4%; calcium, 17.4%; fibrolipid, 6.6%). Plaque morphology did not correlate with l-arg responsiveness.

CONCLUSIONS

Despite extensive atherosclerosis, endothelial function in diseased lower extremity human arteries can be enhanced by l-arg infusion secondary to increased nitric oxide bioactivity. Further studies of l-arg as a therapeutic modality in patients with endothelial dysfunction (ie, acute limb ischemia) are warranted.

Invasive evaluation of plaque morphology of symptomatic superficial femoral artery stenoses using combined near-infrared spectroscopy and intravascular ultrasound

The purpose of this study is to characterize the plaque morphology of severe stenoses in the superficial femoral artery (SFA) employing combined near-infrared spectroscopy and intravascular ultrasound (NIRS-IVUS). Atherosclerosis is the most common cause of symptomatic peripheral arterial disease. Plaque composition of SFA stenoses has been characterized as primarily fibrous or fibrocalcific by non-invasive and autopsy studies. NIRS has been validated to detect lipid-core plaque (LCP) in the coronary circulation. We imaged severe SFA stenoses with NIRS-IVUS prior to revascularization in 31 patients (46 stenoses) with Rutherford claudication ⩾ class 3. Angiographic parameters included lesion location and stenosis severity. IVUS parameters included plaque burden and presence of calcium. NIRS images were analyzed for LCP and maximum lipid-core burden index in a 4-mm length of artery (maxLCBI4mm). By angiography, 38 (82.6%) lesions were calcified and 9 (19.6%) were chronic total occlusions. Baseline stenosis severity and lesion length were 86.0 ± 11.0% and 36.5 ± 46.5 mm, respectively. NIRS-IVUS identified calcium in 45 (97.8%) lesions and LCP in 17 (37.0%) lesions. MaxLCBI4mm was 433 ± 244. All lesions with LCP also contained calcium; there were no non-calcified lesions with LCP. In conclusion, this is the first study of combined NIRS-IVUS in patients with PAD. NIRS-IVUS demonstrates that nearly all patients with symptomatic severe SFA disease have fibrocalcific plaque, and one-third of such lesions contain LCP. These findings contrast with those in patients with acute coronary syndromes, and may have implications regarding the pathophysiology of atherosclerosis in different vascular beds.

The incidence and morphology of Monckeberg's medial calcification in banked vascular segments from a monocentric donor population

Little is known about the real incidence and the clinical relevance of the enigmatic Monckeberg's medial calcification in the patency of the femoral artery allograft. Here we present a retrospective study on 143 multiorgan donors (mean age 38 years, range 14-59 years), to describe the incidence and the morphological features of vascular calcifications in banked femoral arteries suitable for clinical use. In the present series, focal vascular calcifications were present in 36 (25 %) cases, 23 cases localized in the intima, 7 in the media, and 6 were mixed. No correlation was found between the incidence of calcifications and the classical cardiovascular clinical risk factors (n = 9); only hypertension correlated with the medial localization, but not with the incidence, of the calcification (P = 0.017). While the macroscopic exclusion criteria of vascular grafts include atheromatous and not-atheromatous lesions, we ignore the actual impact of Monckeberg's medial calcification on vessel transplantation and allograft life. In our opinion this is a very important topic, since when the histological criteria for Monckeberg's calcification diagnosis are used, 25 % of our young donors population was affected. Whether Monckeberg's medial calcification is a stable arterial condition, apparently underestimated in the general population, or a dynamic process evolving with age and atherosclerosis, or a banking-related vascular alteration, still remain an open issue deserving further studies with subjects of different ages.

Pooled Analysis of the CONFIRM Registries

Purpose: To compare the acute procedure and angiographic outcomes of peripheral artery disease (PAD) patients treated with orbital atherectomy stratified by gender. Methods: The CONFIRM I, II, and III registries are US multicenter, nonrandomized, all-comers registries of PAD patients who were treated with orbital atherectomy. All patients with gender specified in the registry database were included in the current analysis, which compared the final residual stenosis achieved after atherectomy and the rate of acute complications in female and male patients. The 3 registries included 3131 patients with 4761 lesions: 1261 women (mean age 73.2±10.7 years) with 1874 lesions and 1870 men (mean age 70.4±10.2) with 2887 lesions. Results: The women were older (p<0.001) and had a higher but nonsignificant prevalence of critical limb ischemia (p=0.075). After treatment, the final residual stenosis in women vs. men was 9%±11% vs. 11%±11%, respectively (p<0.001). Women had a higher rate of all types of dissection (13.3% vs. 9.9%, p<0.001). However, both genders had similar rates of flow-limiting dissections (1.6% vs. 1.4%, p=0.61), perforation, slow flow, vessel closure, spasm, embolism, and thrombus formation. Conclusion: The gender analysis of the CONFIRM registries revealed that there was successful lesion modification with orbital atherectomy in both men and women; however, women had a higher rate of dissection (all types). This difference is likely because of the older age and higher percentage of critical limb ischemia in women in this cohort. These results, however, suggest that additional studies should be completed to further understand the increased risks for women vs. men during endovascular procedures.

Pooled analysis of the CONFIRM registries: safety outcomes in diabetic patients treated with orbital atherectomy for peripheral artery disease

PURPOSE

To compare the acute outcomes of orbital atherectomy treatment in diabetic vs. non-diabetic patients with peripheral artery disease (PAD).

METHODS

The CONFIRM registry series contained 1842 diabetic patients (1111 men; mean age 70.6±10.2 years) with 2819 lesions and 1247 non-diabetic patients (732 men; mean age 72.9±10.7 years) with 1885 lesions. The composite rate of procedure-related complications, including dissection, perforation, slow flow, vessel closure, spasm, embolism, and thrombus formation, was analyzed for the diabetic and non-diabetic groups.

RESULTS

Diabetics were younger but had a higher prevalence of coronary artery disease (p<0.001), renal disease (p<0.001), hypertension (p<0.001), hyperlipidemia (p<0.001), and lower ankle-brachial index scores (p=0.007). Diabetics had more severe PAD (Rutherford category 4-6; p<0.001), longer lesions (p<0.001), more infrapopliteal lesions (58% vs. 46%, p<0.001), and more lesions with severe and moderate calcium (86% vs. 78%, p<0.001). Diabetic and non-diabetic patients had the same (21.8%) composite rate of procedure-related complications, as well as similar rates of dissection (11.4% vs. 10.8%, p=0.68), embolism (2.2% vs. 2.4%, p=0.67), and thrombus formation (1.3% vs. 1.1%, p=0.75). However, diabetics had lower rates of perforation (0.5% vs. 1.1%, p=0.03) and spasm (5.5% vs. 7.6%, p=0.005), but a higher rate of slow flow (5.0% vs. 3.5%, p=0.02) and a tendency toward increased vessel closure (1.7% vs. 0.9%, p=0.06).

CONCLUSION

Plaque modification with orbital atherectomy resulted in similar low procedure-related complication rates in both the diabetic and non-diabetic groups, despite diabetics having more unfavorable baseline clinical and lesion characteristics. This study suggests that orbital atherectomy is a safe and effective treatment modality in both the diabetic and the non-diabetic populations.

A prospective evaluation of using IVUS during percutaneous superficial femoral artery interventions

BACKGROUND

The outcomes of endovascular interventions of the superficial femoral artery (SFA) are variable. Completion angiography is typically performed to confirm satisfactory outcomes after SFA angioplasty and/or stenting. However, two-dimensional angiography may not accurately reflect the extent of residual stenosis. We sought to determine whether intravascular ultrasound (IVUS) can help with residual disease assessment and procedure outcome.

METHODS

Patients with anticipated SFA disease were prospectively recruited to the study. Patients with primary SFA disease on diagnostic angiography were included. After SFA endovascular intervention with angioplasty and/or stenting, a completion angiogram was performed to confirm satisfactory results before IVUS evaluation. IVUS-detected maximal residual stenosis, maximal residual lesion volume, and number of nonconsecutive posttreatment SFA segments with >50% residual stenosis were evaluated. Periprocedural ankle-brachial indexes (ABIs), Short Form 36 (SF-36) surveys, and Walking Impairment Questionnaires were also collected.

RESULTS

Fifty-nine patients were prospectively enrolled. Thirty-three received angioplasty only, and 26 received angioplasty and stenting. All patients were men, mean age was 67 years, and major comorbidities included coronary artery disease (53%), active smoking (56%), hypertension (88%), and diabetes (68%). The angioplasty-only cohort had more nonconsecutive areas of >50% residual stenosis (P = 0.004), greater residual stenosis (P = 0.03), and smaller minimal lumen diameters after treatment (P = 0.01) than the angioplasty and stenting cohort. However, there was no significant difference in ABI between the 2 groups and no difference in ABI improvement after intervention. Sixty-four percent of all patients demonstrated a >0.2 increase in postintervention ABI. Improvement in ABI at 1 month after procedure significantly correlated with postintervention SF-36 survey physical scores (r = 0.435, P = 0.007).

CONCLUSIONS

IVUS evaluation provides more-accurate intraprocedural insight on the extent of residual stenosis after SFA interventions. Future studies are warranted to determine whether IVUS-guided postangioplasty and/or stenting can impact long-term interventional outcome.

Cost-effectiveness analysis of orbital atherectomy plus balloon angioplasty vs balloon angioplasty alone in subjects with calcified femoropopliteal lesions

Introduction

As cost considerations become increasingly critical when selecting optimal endovascular treatment strategies, a cost-benefit analysis was conducted comparing the Diamondback 360°® Orbital Atherectomy System (OAS) (Cardiovascular Systems, Inc., St Paul, MN, USA) and balloon angioplasty (BA) vs BA alone for treatment of calcified femoropopliteal lesions.

Patients and methods

The clinical outcomes from COMPLIANCE 360°, a prospective, multicenter, randomized study comparing OAS+BA vs BA alone for treatment of calcified femoropopliteal lesions, were correlated with cost data and previously published quality of life data. Site of service, hospital charges, and associated medical resource utilization were obtained from Uniform Billing statements for index treatments and associated revascularizations out to 1 year. Hospital costs were estimated using hospital-specific, procedure-specific cost-to-charge ratios. Length of stay and procedural data were collected from participating study sites.

Results

Twenty-five subjects with 38 lesions and 25 subjects with 27 lesions were randomized to the OAS+BA and BA-alone groups, respectively. Mean hospital charges (US$51,755 vs US$39,922) and estimated hospital costs (US$15,100 vs US$11,016) were higher for OAS+BA compared with BA alone (not statistically significant). Stent utilization was statistically significantly higher with BA-alone treatment for all subjects (1.1 vs 0.1, P=0.001) and in the subset of subjects with one lesion (1.0 vs 0.1, P<0.00001). There was a significant difference in cost for single-lesion versus multiple-lesion treatment. Using costs and quality-adjusted life years (QALYs) for the single-lesion cohort, the 1-year incremental cost of OAS+BA vs BA alone was US$549, and incremental QALY was 0.16. This results in an incremental cost-effectiveness ratio of US$3,441, well below the US$50,000 threshold.

Conclusion

One-year index procedure cost and cost-effectiveness were comparable for OAS+BA vs BA alone. This study provides compelling cost-effectiveness data for using atherectomy for treatment of calcified femoropopliteal lesions, a longstanding challenge for peripheral artery disease interventionalists.

Effective endovascular treatment of calcified femoropopliteal disease with directional atherectomy and distal embolic protection: final results of the DEFINITIVE Ca⁺⁺ trial

Objectives

The purpose of the DEFINITIVE Ca⁺⁺ study was to evaluate the safety and effectiveness of directional atherectomy and distal embolic protection, used together to treat moderate to severely calcified femoropopliteal lesions.

Background

Despite advances in endovascular treatment modalities, treatment of calcified lesions remains a challenge.

Methods

A total of 133 subjects with 168 moderate to severely calcified lesions were enrolled. Lesions were treated with directional atherectomy devices, coupled with distal embolic protection.

Results

The 30-day freedom from MAE rate was 93.1%. Per angiographic core laboratory assessment, the primary effectiveness endpoint (≤50% residual diameter stenosis) was achieved in 92.0% (lower confidence bound of 87.6%) of lesions. By core lab analysis, these results did not achieve the success criteria (90%) for the primary effectiveness objective. Per site assessment, the objective was met with the endpoint being achieved in 97.0% (lower confidence bound 93.8%). A mean residual diameter stenosis of 33.3% was achieved with the directional atherectomy device. This was further decreased to 24.1% with the use of adjunctive therapy. The proportion of asymptomatic subjects [Rutherford Clinical Category (RCC) = 0] increased from 0% at baseline to 52.3% at the 30-day follow-up visit. In total, 88.5% of subjects experienced an improvement of one or more Rutherford categories.

Conclusions

The results of the DEFINITIVE Ca++ study demonstrate that the SilverHawk™ and TurboHawk™ atherectomy devices are safe and effective in the endovascular treatment of moderate to severely calcified lesions in the superficial femoral and/or popliteal arteries when used with the SpiderFX™ distal embolic protection device. © 2014 Wiley Periodicals, Inc.

In vivo assessment of endothelial function in human lower extremity arteries

OBJECTIVE

Endothelial function has been measured in preclinical studies in human brachial and coronary arteries but not in lower extremity arteries affected by atherosclerosis. We describe a novel, first-in-man evaluation of endothelial function of the superficial femoral arteries (SFAs) in patients with peripheral arterial disease (PAD).

METHODS

Enrolled were 25 patients with PAD requiring lower extremity angiography. Endothelial-dependent relaxation was measured using intravascular ultrasound (IVUS) imaging and a Doppler flow wire after the infusion of acetylcholine (Ach). IVUS-derived virtual histology of the same vessel was calculated. Endothelial-independent relaxation was measured with an infusion of nitroglycerin (200 μg). Levels of nitric oxide and serum nitric oxide metabolites were determined by laboratory analysis.

RESULTS

Patients (48% male; mean age, 62 years) had a history of hypertension (80%), coronary disease (36%), and diabetes (40%). The mean SFA diameter was 5.2 ± 1 mm (range, 3.2-6.9 mm). Patients tolerated Ach infusion with no adverse events. Endothelial-dependent relaxation increased over baseline for all patients with Ach infusion of 10(-6) to 10(-4). At Ach 10(-4), diameter (0.5%) and area (1.8%) changes in the diseased SFAs were modest and insignificant; however, average peak velocity of blood flow significantly increased 26%, 46%, and 63% with an Ach 10(-6) to 10(-4) infusion. Calculations of limb volumetric flow (68% at Ach 10(-4)) were significantly increased after Ach infusion. Lower extremity nitric oxide levels were slightly lower than systemic venous levels (P = .04). Nitroglycerin infusion indicated normal smooth muscle responsiveness (3% diameter, 9% area, and 116% velocity change over baseline). IVUS-virtual histology plaque stratification indicated predominantly fibrous morphology (46%; necrotic core, 29%; calcium, 18%). Atheroma burden was 14.9 ± 5.5 mm(3)/cm and did not correlate with endothelial responsiveness.

CONCLUSIONS

Endothelial function can be measured directly in human lower extremity arteries at the sites of vascular disease. Despite extensive atherosclerosis, endothelial function is still intact. These data support the application of regional endothelial-specific biologic therapies in patients with PAD.

Techniques to harvest diseased human peripheral arteries and measure endothelial function in an ex vivo model

OBJECTIVE

Endothelial dysfunction has been studied in animal models. However, direct evidence of endothelial function from human vessels is limited. Our objectives were to optimize methods in harvesting human arteries from amputation specimens, determine endothelial function, and measure responsiveness to l-arginine, a nitric oxide precursor.

METHODS

Fresh amputation specimens were transferred expeditiously from the operating room to the bench laboratory for dissection and arterial harvest in an Investigational Review Board-approved protocol. Popliteal and tibial vessels were examined in pilot experiments leading to the use of the anterior tibial artery in consecutive experiments. Human lower extremity anterior tibial artery segments were harvested from 14 amputation specimens. Specimens were rapidly collected and divided for endothelial-dependent relaxation (EDR) studies in a tissue bath apparatus, immunohistochemistry, and intravascular ultrasound-derived virtual histology. A total of 47 ring segments were studied. The data were compared with two-way analysis of variance.

RESULTS

Human lower extremity arteries exhibited low responsiveness to acetylcholine (EDR, 24.9%; acetylcholine, 10(-4)). L-arginine supplementation enhanced EDR by 38.5% (P < .0001). N-nitro-L-arginine methyl ester abrogated EDR (P < .0001) in vessels exposed to L-arginine. Arterial responsiveness was intact in all vessels (endothelial independent relaxation to sodium nitroprusside, 113.2% ± 28.1%). Histology and immunohistochemistry confirmed intact endothelium by morphometric analysis, cluster of differentiation 31, endothelial nitric oxide synthase, and arginase II staining. Intravascular ultrasound-derived virtual histology indicated atheroma burden was 11.9 ± 4.7 mm(3)/cm, and plaque stratification indicated fibrous morphology was predominant (59.9%; necrotic core, 16.9%; calcium, 11.2%). Variations in plaque morphology did not correlate with endothelial function or responsiveness to L-arginine.

CONCLUSIONS

Human lower extremity arteries demonstrate low baseline endothelial function in patients requiring amputation. Endothelial dysfunction is improved by L-arginine supplementation in an ex vivo model. These results support strategies to increase local levels of nitric oxide in human vessels.

Comparison of orbital atherectomy plus balloon angioplasty vs. balloon angioplasty alone in patients with critical limb ischemia: results of the CALCIUM 360 randomized pilot trial

PURPOSE

To evaluate the role of orbital atherectomy in calcified infrapopliteal arteries in patients with critical limb ischemia compared to balloon angioplasty (BA) alone.

METHODS

A randomized multicenter study was undertaken to evaluate short and 1-year outcomes in 50 patients (32 men; mean age 71 years, range 40-90) with confirmed calcified lesions using 1∶1 randomization to the Diamondback 360° Orbital Atherectomy System followed by BA vs. BA alone. All patients had severe (≥50% stenosis) peripheral artery disease (Rutherford classification 4-6) in the popliteal, tibial, and/or peroneal arteries. The primary endpoint was defined as restoration of a normal lumen (residual stenosis ≤30%) with no bailout stenting or dissection types C through F. Scheduled follow-up visits were conducted according to a common protocol at 1, 6, and 12 months.

RESULTS

Procedural success was 93.1% (27/29 lesions) for atherectomy + BA patients and 82.4% (28/34 lesions) for BA alone (p = 0.27). Bailout stenting was needed in 2 (6.9%) of the 29 atherectomy + BA lesions and in 5 (14.3%) of the 35 BA-treated lesions (p = 0.44). At 1 year, there were no amputations in either group related to the index procedure. Estimates for freedom from target vessel revascularization and all-cause mortality were 93.3% and 100% in the atherectomy + BA group vs. 80.0% (p = 0.14) and 68.4% (p = 0.01) in the BA group, respectively. Proportional hazard models evaluating survival time vs. status of residual stenosis determined a hazard ratio for major adverse events of 5.6 for patients with an acute post-procedure residual stenosis >30% (p = 0.01).

CONCLUSION

Debulking with orbital atherectomy appeared to increase the chance of reaching a desirable angioplasty result, with less acute need for bailout stenting and a higher procedure success. A negative association between procedure success and risk of serious adverse outcomes should encourage larger confirmatory studies.

Correlation between arterial FDG uptake and biomarkers in peripheral artery disease

OBJECTIVES

A prospective, multicenter (18)fluorine-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET)/computed tomography (CT) imaging study was performed to estimate the correlations among arterial FDG uptake and atherosclerotic plaque biomarkers in patients with peripheral artery disease.

BACKGROUND

Inflammation within atherosclerotic plaques is associated with instability of the plaque and future cardiovascular events. Previous studies have shown that (18)F-FDG-PET/CT is able to quantify inflammation within carotid artery atherosclerotic plaques, but no studies to date have investigated this correlation in peripheral arteries with immunohistochemical confirmation.

METHODS

Thirty patients across 5 study sites underwent (18)F-FDG-PET/CT imaging before SilverHawk atherectomy (FoxHollow Technologies, Redwood City, California) for symptomatic common or superficial femoral arterial disease. Vascular FDG uptake (expressed as target-to-background ratio) was measured in the carotid arteries and aorta and femoral arteries, including the region of atherectomy. Immunohistochemistry was performed on the excised atherosclerotic plaque extracts, and cluster of differentiation 68 (CD68) level as a measure of macrophage content was determined. Correlations between target-to-background ratio of excised lesions, as well as entire arterial regions, and CD68 levels were determined. Imaging was performed during the 2 weeks before surgery in all cases.

RESULTS

Twenty-one patients had adequate-quality (18)F-FDG-PET/CT peripheral artery images, and 34 plaque specimens were obtained. No significant correlation between lesion target-to-background ratio and CD68 level was observed.

CONCLUSIONS

There were no significant correlations between CD68 level (as a measure of macrophage content) and FDG uptake in the peripheral arteries in this multicenter study. Differences in lesion extraction technique, lesion size, the degree of inflammation, and imaging coregistration techniques may have been responsible for the failure to observe the strong correlations with vascular FDG uptake observed in previous studies of the carotid artery and in several animal models of atherosclerosis.

Optimal techniques with the Diamondback 360° System achieve effective results for the treatment of peripheral arterial disease

The Diamondback 360® Orbital PAD System (DB360) is a novel orbital atherectomy system for the treatment of calcified lower extremity lesions associated with peripheral arterial disease (PAD). This percutaneous, endovascular system incorporates the use of centrifugal force and differential sanding to modify plaque morphologies. The mechanism of differential sanding discriminates between compliant arterial tissue and diseased fibro-calcific or calcific plaque. An eccentrically mounted diamond-coated crown orbits at high speeds and removes a thin layer of calcific plaque with each pass of the crown. The crown creates a more concentric, smooth vessel lumen with increased diameter, increased lesion compliance and improved blood flow while protecting the vessel media. As a result, the risk for post-procedure thrombus formation and potential for restenosis may be reduced. The risk of intra-procedural events (slow flow, hemolysis, spasm and pain) may be reduced due to the design of this orbital sanding system along with proper technique. Extensive benchtop, in vivo, and clinical testing has confirmed these results and is presented within this paper. In addition, guidelines for selecting the most appropriate crown size and type (solid versus classic) and step-by-step procedural technique and pharmacology information are presented. The DB360 System provides a safe, efficacious, and cost-effective endovascular method for PAD treatment. Careful understanding of procedural methods, use of pharmacological drugs, and understanding of device operation contributes to improved treatment success.

T1-weighted-SPACE dark blood whole body magnetic resonance angiography (DB-WBMRA): initial experience

PURPOSE

To evaluate the feasibility of the dark blood fast spin echo (FSE) T1-weighted-Sampling Perfection with Application of optimized Contrasts using different flip angle Evolution (T1w-SPACE) sequence in assessing whole body arterial wall information from the extracranial carotids to the popliteal artery.

MATERIALS AND METHODS

Twenty-eight subjects were subjected to noncontrast, dark blood whole body magnetic resonance angiography (DB-WBMRA) using a T1w-SPACE sequence optimized for each of the individual stations: carotid artery, thoracic aorta, abdominal aorta, and thigh/superficial femoral artery (SFA). Image quality/vessel wall visualization and the time required to image the four stations were evaluated. Two observers checked the reproducibility of vessel wall depiction by performing quantitative measurements in registered initial and repeat studies (six subjects) of vessel wall and lumen area at 17 locations along the arterial tree.

RESULTS

In 25 of the 28 scanned subjects, dark blood arterial images acquired in approximately 1 hour total imaging time allowed whole body arterial vessel wall visualization. Quantitative measurements showed high correlation between the initial and repeat studies for each of the observers as well as high interobserver reproducibility (r > 0.95; P < 0.01).

CONCLUSION

DB-WBMRA using T1w-SPACE is feasible and can be performed with a high degree of reliability.

Evaluation of peripheral atherosclerosis: a comparative analysis of angiography and intravascular ultrasound imaging

OBJECTIVE

Angiography remains a critical component for diagnostic imaging and therapeutic intervention in peripheral arterial disease (PAD). The goal of this study was to compare angiography with corresponding intravascular ultrasound (IVUS) imaging of the same vessels in patients with PAD.

METHODS

From 2004 to 2008, 93 patients undergoing angiography for PAD were recruited in a prospective observational analysis. At the time of angiography, diseased lower extremities were interrogated using a 10-cm IVUS pullback with registration points. IVUS data were analyzed with radiofrequency techniques for vessel and lumen diameter, plaque volume, plaque composition, and cross-sectional area. Similarly, three vascular surgeons blinded to the IVUS data graded corresponding angiographic images according to vessel diameter, degree of stenosis, degree of calcification, and extent of eccentricity. Statistical analyses of matched IVUS images and angiograms were performed.

RESULTS

The distribution of demographic and risk variables were typical for PAD: 54% male, 96% hypertension, 78% hyperlipidemia, 44% diabetic, 87% tobacco history, 65% coronary artery disease, and 10% end-stage renal disease. Symptoms precipitating the angiographic evaluation included claudication (53%), rest pain (18%), and tissue loss (29%). Angiographic and IVUS interpretation were similar for luminal diameters, but external vessel diameter was greater by IVUS imaging (7.0 +/- 0.7 vs 5.2 +/- 0.8 mm, P < .05). The two-dimensional diameter method resulted in a significant correlation for stenosis determination (r = 0.84); however, IVUS determination of vessel area stenosis was greater by 10% (95% confidence interval, 0.3%-21%, P < .05). IVUS imaging indicated that a higher proportion of plaques were concentric. Grading of calcification was moderate to severe in 40% by angiography but in only 7% by IVUS (P < .05).

CONCLUSIONS

In the evaluation of PAD, angiography and IVUS imaging provide similar luminal diameters and diameter-reducing stenosis measurements. Determination of overall vessel diameter and interpretation of plaque morphology by angiography are discordant from IVUS-derived data.