Infrapopliteal Endovascular Interventions for Claudication Are Associated with Poor Long-Term Outcomes in Medicare-Matched Registry Patients.

BACKGROUND: There are limited data supporting or opposing the use of infrapopliteal peripheral vascular interventions (PVI) for the treatment of claudication. OBJECTIVES: We aimed to evaluate the association of infrapopliteal PVI with long-term outcomes compared with isolated femoropopliteal PVI for the treatment of claudication. METHODS: We conducted a retrospective analysis of all patients in the Medicare-matched Vascular Quality Initiative database who underwent an index infrainguinal PVI for claudication from January 2004-December 2019 using Cox proportional hazards models. RESULTS: Of 14,261 patients (39.9% female; 85.6% age ≥65 years, 87.7% non-Hispanic white) who underwent an index infrainguinal PVI for claudication, 16.6% (N=2,369) received an infrapopliteal PVI. The median follow-up after index PVI was 3.7 years (IQR 2.1-6.1). Compared to patients who underwent isolated femoropopliteal PVI, patients receiving any infrapopliteal PVI had a higher 3-year cumulative incidence of conversion to CLTI (33.3% vs. 23.8%; P<0.001); repeat PVI (41.0% vs. 38.2%; P<0.01); and amputation (8.1% vs. 2.8%; P<0.001). After risk-adjustment, patients undergoing infrapopliteal PVI had a higher risk of conversion to CLTI (aHR 1.39, 95% CI, 1.25-1.53); repeat PVI (aHR 1.10, 95% CI, 1.01-1.19); and amputation (aHR 2.18, 95% CI, 1.77-2.67). Findings were consistent after adjusting for competing risk of death; in a 1:1 propensity-matched analysis; and in subgroup analyses stratified by TASC disease, diabetes, and end-stage kidney disease. CONCLUSIONS: Infrapopliteal PVI is associated with worse long-term outcomes than femoropopliteal PVI for claudication. These risks should be discussed with patients.

Practice Patterns of Peripheral Vascular Interventions for Peripheral Artery Disease in the Office-Based Laboratory Setting versus Outpatient Hospital.

OBJECTIVE: Controversy exists regarding the value and limitations of different sites of service for peripheral artery disease (PAD) treatment. We aimed to examine practice patterns associated with peripheral vascular interventions (PVI) performed in the office-based laboratory (OBL) vs. outpatient hospital site of service using a nationally representative database. METHODS: Using 100% Medicare fee-for-service claims data, we identified all patients undergoing PVI for claudication or chronic limb-threatening ischemia (CLTI) between 01/2017 and 12/2022. We evaluated the associations of patient and procedure characteristics with site of service using multivariable hierarchical logistic regression. We used multinomial regression models to estimate the relative risk ratios (RRR) of site of service and intervention type (angioplasty, stent, atherectomy) and intervention level (iliac, femoropopliteal, tibial) after adjusting for baseline patient characteristics and clustering by physician. RESULTS: Of 848,526 PVI, 485,942 (57.3%) were performed in an OBL. OBL use increased significantly over time from 48.3% in 2017 to 65.5% in 2022 (P<0.001). Patients treated in OBLs were more likely to be Black (aOR 1.14, 95%CI 1.11-1.18) or other non-white race (aOR 1.13, 95%CI 1.08-1.18), have fewer comorbidities, and receive treatment for claudication vs. CLTI (aOR 1.30, 95%CI 1.26-1.33) compared to patients treated in outpatient hospital settings. Physicians with majority practice (>50% procedures) in an OBL were more likely to practice in urban settings (aOR 21.58, 95%CI 9.31-50.02), specialize in radiology (aOR 18.15, 95%CI 8.92- 36.92), and have high-volume PVI practices (aOR 2.15, 95%CI 2.10-2.29). The median time from diagnosis to treatment was shorter in OBLs, particularly for patients with CLTI (29 vs. 39 days, P<0.001). The OBL setting was the strongest predictor of patients receiving an atherectomy alone (aRRR 6.67, 95%CI 6.59-6.76) or atherectomy+stent (aRRR 10.84, 95%CI 10.64-11.05), and these findings were consistent in subgroup analyses stratified by PVI indication. OBL setting was also associated with higher risk of tibial interventions for both claudication (aRRR 3.18, 95%CI 3.11-3.25) and CLTI (aRRR 1.89, 95%CI 1.86-1.92). Average reimbursement (including procedure and facility fees) was slightly higher for OBLs compared to the hospital ($8,742/case vs. $8,459/case; P<0.001). However, in a simulated cohort resetting the OBL's intervention type distribution to that of the hospital, OBLs were associated with a hypothetical cost savings of $221,219,803 overall and $2,602 per case. CONCLUSION: The OBL site of service was associated with greater access to care for non-white patients and shorter time from diagnosis to treatment, but more frequently performed high-cost interventions compared to the outpatient hospital setting. The benefit to patients from improved access to PAD care in OBL settings must be balanced with the potential limitations of receiving differential care.

Infrapopliteal Peripheral Vascular Interventions for Claudication are Performed Frequently in the USA and Are Associated with Poor Long Term Outcomes.

OBJECTIVE: Infrapopliteal peripheral vascular interventions (PVIs) for claudication are still performed in the USA. This study aimed to evaluate whether infrapopliteal PVI is associated with worse long term outcomes than isolated femoropopliteal PVI for treatment of claudication. METHODS: A retrospective analysis of fee for service claims in a national administrative database was conducted using 100% of the Medicare fee for service claims between 2017 and 2019 to capture all Medicare beneficiaries who underwent an index infra-inguinal PVI for claudication. Hierarchical Cox proportional hazards models were performed to assess the association of infrapopliteal PVI with conversion to chronic limb threatening ischaemia (CLTI), repeat PVI, and major amputation. RESULTS: In total, 36 147 patients (41.1% female; 89.7% age ≥ 65 years; 79.0% non-Hispanic White race) underwent an index PVI for claudication, of whom 32.6% (n = 11 790) received an infrapopliteal PVI. Of these, 61.4% (n = 7 245) received a concomitant femoropopliteal PVI and 38.6% (n = 4 545) received an isolated infrapopliteal PVI. The median follow up time was 3.5 years (interquartile range 2.7, 4.3). Patients receiving infrapopliteal PVI had a higher three year cumulative incidence of conversion to CLTI (26.0%; 95% confidence interval [CI] 24.9 - 27.2% vs. 19.9%; 95% CI 19.1 - 20.7%), repeat PVI (56.0%; 95% CI 54.8 - 57.3% vs. 45.7%; 95% CI 44.9 - 46.6%), and major amputation (2.2%; 95% CI 1.8 - 2.6% vs. 1.3%; 95% CI 1.1 - 1.5%) compared with patients receiving isolated femoropopliteal PVI. After adjusting for patient and physician level characteristics, the risk of conversion to CLTI (adjusted hazard ratio [aHR] 1.31, 95% CI 1.23 - 1.39), repeat PVI (aHR 1.12, 95% CI 1.05 - 1.20), and major amputation (aHR 1.72, 95% CI 1.42 - 2.07) remained significantly higher for patients receiving infrapopliteal PVI. An increasing number of infrapopliteal vessels treated during the index intervention was associated with increasingly poor outcomes (p < .001 for trend). CONCLUSION: Infrapopliteal PVI for claudication is associated with worse long term outcomes relative to isolated femoropopliteal PVI.

Representation of Women and Racially and Ethnically Marginalized Principal Investigators in Vascular Device Trials.

This quality improvement study describes the lack of diversity in trial leadership, especially in arterial disease device trials, and recommends action steps.

Risks and Benefits of the Proposed Amputation Reduction and Compassion Act for Disadvantaged Patients.

Racial, ethnic, and socioeconomic disparities in the major risk factors for vascular disease and access to vascular specialist care are well-documented.1-3 The higher incidence of diabetes, peripheral artery disease (PAD), and related nontraumatic lower extremity amputation among racial and ethnic minority groups, those of low socioeconomic status, and those with poor access to care based on geography (together, referred to below as disadvantaged groups) are particularly pervasive.1,4-9 Practitioners of vascular surgery and endovascular therapy are uniquely positioned to address health inequities in lower extremity screening, medical management, intervention, and limb preservation among the population of adults at the highest risk for limb loss.

Corrigendum: Implementation of a patient-centered remote wound monitoring system for management of diabetic foot ulcers.

[This corrects the article DOI: 10.3389/fendo.2023.1157518.].

Socioeconomic status fails to account for worse outcomes in non-Hispanic black patients undergoing carotid revascularization.

OBJECTIVE: Previous studies have reported an association of Black race with worse carotid revascularization outcomes, but rarely include socioeconomic status as a confounding covariate. We aimed to assess the association of race and ethnicity with in-hospital and long-term outcomes following carotid revascularization before and after accounting for socioeconomic status. METHODS: We identified non-Hispanic Black and non-Hispanic white patients who underwent carotid endarterectomy, transfemoral carotid stenting, or transcarotid artery revascularization between 2003 and 2022 in the Vascular Quality Initiative. Primary outcomes were in-hospital stroke/death and long-term stroke/death. Multivariable logistic regression and Cox proportional hazards models were used to assess the association of race with perioperative and long-term outcomes after adjusting for baseline characteristics using a sequential model approach without and with consideration of Area Deprivation Index (ADI), a validated composite marker of socioeconomic status. RESULTS: Of 201,395 patients, 5.1% (n = 10,195) were non-Hispanic Black, and 94.9% (n = 191,200) were non-Hispanic white. Mean follow-up time was 3.4±0.01 years. A disproportionately high percentage of Black patients were living in more socioeconomically deprived neighborhoods relative to their white counterparts (67.5% vs 54.2%; P < .001). After adjusting for demographic, comorbidity, and disease characteristics, Black race was associated with greater odds of in-hospital (adjusted odds ratio [aOR], 1.24; 95% confidence interval [CI], 1.10-1.40) and long-term stroke/death (adjusted hazard ratio [aHR], 1.13; 95% CI, 1.04-1.23). These associations did not substantially change after additionally adjusting for ADI; Black race was persistently associated with greater odds of in-hospital (aOR, 1.23; 95% CI, 1.09-1.39) and long-term stroke/death (aHR, 1.12; 95% CI, 1.03-1.21). Patients living in the most deprived neighborhoods were at greater risk of long-term stroke/death compared with patients living in the least deprived neighborhoods (aHR, 1.19; 95% CI, 1.05-1.35). CONCLUSIONS: Non-Hispanic Black race is associated with worse in-hospital and long-term outcomes following carotid revascularization despite accounting for neighborhood socioeconomic deprivation. There appears to be unrecognized gaps in care that prevent Black patients from experiencing equitable outcomes following carotid artery revascularization.

Implementation of a patient-centered remote wound monitoring system for management of diabetic foot ulcers.

Background: Regular clinical assessment is critical to optimize lower extremity wound healing. However, family and work obligations, socioeconomic, transportation, and time barriers often limit patient follow-up. We assessed the feasibility of a novel, patient-centered, remote wound management system (Healthy.io Minuteful for Wound Digital Management System) for the surveillance of lower extremity wounds. Methods: We enrolled 25 patients from our outpatient multidisciplinary limb preservation clinic with a diabetic foot ulcer, who had undergone revascularization and podiatric interventions prior to enrollment. Patients and their caregivers were instructed on how to use the digital management system and asked to perform one at-home wound scan per week for a total of 8 weeks using a smartphone application. We collected prospective data on patient engagement, smartphone app useability, and patient satisfaction. Results: Twenty-five patients (mean age 65.5 ± 13.7 years, 60.0% male, 52.0% Black) were enrolled over 3 months. Mean baseline wound area was 18.0 ± 15.2 cm2, 24.0% of patients were recovering from osteomyelitis, and post-surgical WiFi stage was 1 in 24.0%, 2 in 40.0%, 3 in 28.0%, and 4 in 8.00% of patients. We provided a smartphone to 28.0% of patients who did not have access to one that was compatible with the technology. Wound scans were obtained by patients (40.0%) and caregivers (60.0%). Overall, 179 wound scans were submitted through the app. The mean number of wound scans acquired per patient was 0.72 ± 0.63 per week, for a total mean of 5.80 ± 5.30 scans over the course of 8 weeks. Use of the digital wound management system triggered an early change in wound management for 36.0% of patients. Patient satisfaction was high; 94.0% of patients reported the system was useful. Conclusion: The Healthy.io Minuteful for Wound Digital Management System is a feasible means of remote wound monitoring for use by patients and/or their caregivers.

Association of Year of Surgery and Carotid Stenting Outcomes in High-risk Patients, 2015-2021.

This cohort study quantifies the yearly trends and outcomes of transcarotid artery revascularization vs transfemoral carotid artery stenting among high-risk patients from 2015 to 2021.

A 10-Year Analysis of Representation of Women in Patent Applications and NIH Funding in Vascular Surgery.

BACKGROUND: There has been an increasing focus on gender disparities in the medical field and in the field of vascular surgery specifically. We aimed to characterize gender representation in vascular surgery innovation over the past 10 years, using metrics of patents and National Institutes of Health (NIH) support. METHODS: We performed a retrospective review of all vascular-related patent filings (Google Scholar) and NIH-funded grants (NIH RePORTER) over a 10-year period (January 1st, 2012, to December 31st, 2021). Gender-API (Application Programming Interface) was used to identify the gender of the inventors, with manual confirmation of a 10% random sample. Gender representation for patent inventors and grant principal investigators (PIs) were compared using Chi-squared and Student's t-tests as appropriate. Yearly temporal changes in representation were analyzed using Wilcoxon signed-rank tests and linear regression analyses. RESULTS: We identified 2,992 unique vascular device patents with 6,093 associated inventors over 10 years. Women were underrepresented in patent authorship overall (11.5%), and were least likely to be listed as first inventor (8.9%) and most commonly fourth and fifth inventors (15.5% and 14.1%, respectively) compared to men. There was no significant change in representation of women inventors over time (-0.2% females per year, 95% confidence interval (CI) -0.54 to 0.10). We identified 1736 total unique NIH grants, with 23.8% of funded projects having women PIs. There was an increase in the proportion of women PIs over time (+1.31% per year, 95% CI 0.784 to 1.855; P < 0.001). Projects with women PIs received mean total awards that were significantly lower than projects with men PIs ($350,485 ± $220,072 vs. $451,493 ± $411,040; P < 0.001), but the overall ratio of funding:women investigators improved over time (+$11,531 per year, 95% CI $6,167 to $16,895; P = 0.0011). CONCLUSIONS: While we have made strides in increasing the number of women in the surgical research space, there is still room for improvement in funding parity. In addition, we found substantial and persistent room for improvement in representation of women in surgical innovation. As we enter a new frontier of surgery hallmarked by equalizing gender representation, these data should serve as a call-to-action for initiative aimed at rebuilding the foundation of surgical innovations upon equal gender representation.

Disparities in limb preservation and associated socioeconomic burden among patients with diabetes and/or peripheral artery disease in the United States.

Racial, ethnic, socioeconomic, and geographic disparities in limb preservation and nontraumatic lower extremity amputation (LEA) are consistently demonstrated in populations with diabetes and peripheral artery disease (PAD). Higher rates of major LEA in disadvantaged groups are associated with increased health care utilization and higher costs of care. Functional decline that often follows major LEA confers substantial risk of disability and premature mortality, and the burden of these outcomes is more prevalent in racial and ethnic minority groups, people with low socioeconomic status, and people in geographic regions where limited resources or distance from specialty care are barriers to access. We present a narrative review of the existing literature on estimated costs of diabetic foot disease and PAD, inequalities in care that contribute to excess costs, and disparities in outcomes that lead to a disproportionate burden of diabetes- and PAD-related LEA on systematically disadvantaged populations.

Practice patterns surrounding the use of tibial interventions for claudication in the Medicare population.

OBJECTIVE: At present, no data are available to support the use of tibial interventions in the treatment of claudication. We characterized the practice patterns surrounding tibial peripheral vascular interventions (PVIs) for patients with claudication in the United States. METHODS: Using 100% Medicare fee-for-service claims from 2017 to 2019, we conducted a retrospective analysis of all patients who underwent an index PVI for claudication. Patients with any previous PVI, acute limb ischemia, or chronic limb-threatening ischemia in the preceding 12 months were excluded. The primary outcome was the receipt or delivery of tibial revascularization during an index PVI for claudication, defined as tibial PVI with or without concomitant femoropopliteal PVI. Univariable comparisons and multivariable hierarchical logistic regression were used to assess the patient and physician characteristics associated with the use of tibial PVI for claudication. RESULTS: Of 59,930 Medicare patients who underwent an index PVI for claudication between 2017 and 2019, 16,594 (27.7%) underwent a tibial PVI (isolated tibial PVI, 38.5%; tibial PVI with concomitant femoropopliteal PVI, 61.5%). Of the 1542 physicians included in our analysis, the median physician-level tibial PVI rate was 20.0% (interquartile range, 9.1%-37.5%). Hierarchical logistic regression suggested that patient-level characteristics associated with tibial PVI for claudication included male sex (adjusted odds ratio [aOR], 1.23), increasing age (aOR, 1.30-1.96), Black race (aOR, 1.47), Hispanic ethnicity (aOR, 1.86), diabetes (aOR, 1.36), no history of hypertension (aOR, 1.12), and never-smoking status (aOR, 1.64; P < .05 for all). Physician-level characteristics associated with tibial PVI for claudication included early-career status (aOR, 2.97), practice location in the West (aOR, 1.75), high-volume PVI practice (aOR, 1.87), majority of practice in an ambulatory surgery center or office-based laboratory setting (aOR, 2.37), and physician specialty. The odds of vascular surgeons performing tibial PVI were significantly lower compared with radiologists (aOR, 2.98) and cardiologists (aOR, 1.67; P < .05 for all). The average Medicare reimbursement per patient was dramatically higher for physicians performing high rates of tibial PVI (quartile 4 vs quartile 1-3, $12,023.96 vs $692.31 per patient; P < .001). CONCLUSIONS: Tibial PVI for claudication was performed more often by nonvascular surgeons in high-volume practices and high-reimbursement settings. Thus, a critical need exists to reevaluate the indications, education, and reimbursement policies surrounding these procedures.

Females are less likely to receive best medical therapy for stroke prevention before and after carotid revascularization than males.

BACKGROUND: Current professional guidelines recommend best medical therapy (BMT) with statin agents and antiplatelet therapy for primary and secondary stroke prevention in patients with carotid artery stenosis. We aimed to assess the association of patient sex with preoperative BMT in patients undergoing carotid revascularization. METHODS: We performed a retrospective review of Vascular Quality Initiative patients who underwent carotid endarterectomy or carotid artery stenting between January 2003 and February 2022. Multivariable logistic regression models were used to assess the association of patient sex with preoperative BMT after adjusting for sociodemographic, comorbidity, and disease severity characteristics. In-hospital outcomes were assessed by sex and preoperative BMT status. RESULTS: Of 214,008 patients who underwent carotid revascularization, 38.7% (n = 82,855) were female and 61.3% (n = 131,153) were male. Overall, 77.2% (n = 63,922) of females were on preoperative BMT, compared with 80.4% (n = 105,375) of males (P < .001). After adjusting for baseline differences, females had 11% lower odds of being on BMT compared with males (adjusted odds ratio, 0.89; 95% confidence interval, 0.86-0.91). Postoperatively, females had 18% lower odds of being prescribed BMT than males (adjusted odds ratio, 0.82; 95% confidence interval, 0.79-0.84). In-hospital stroke (1.20% vs 1.51%), death (0.37% vs 0.66%), and stroke/death (1.46% vs 1.98%) were all significantly lower for patients on BMT (all P < .001). CONCLUSIONS: There is a significant discrepancy in the proportion of females versus males receiving preoperative BMT for stroke prevention before carotid artery revascularization. In-hospital outcomes are worse in patients without BMT, highlighting the importance of raising awareness and implementing targeted interventions to improve preoperative adherence to stroke prevention guidelines.

Medicare Beneficiaries In Disadvantaged Neighborhoods Increased Telemedicine Use During The COVID-19 Pandemic.

Anticipating a growing need for health care during the COVID-19 pandemic, the Centers for Medicare and Medicaid Services expanded telemedicine coverage in the United States on March 6, 2020. In this study we used roughly thirty million Medicare fee-for-service claims to quantify outpatient telemedicine use before and after the Medicare telemedicine coverage waiver and to examine the association of telemedicine use with the Area Deprivation Index, a comprehensive measure of neighborhood socioeconomic disadvantage. Before the waiver, 0.42 percent of patients had at least one outpatient telemedicine visit, with no significant differences between people residing in the most versus the least disadvantaged neighborhoods. With the waiver, 9.97 percent of patients had at least one outpatient telemedicine visit, with the highest odds of utilization seen for people residing in the most disadvantaged neighborhoods. After adjustment, our data suggest that the coverage waiver increased access to telemedicine for all Medicare populations, including people residing in the most disadvantaged neighborhoods, although the odds of use were persistently lower with increasing age. Overall, these findings are encouraging, but they illuminate a need for targeted interventions to improve telemedicine access further.

Transcarotid artery revascularization is associated with similar outcomes to carotid endarterectomy regardless of patient risk status.

BACKGROUND: Carotid artery stenting (CAS), including both transfemoral carotid artery stenting (TFCAS) and transcarotid artery revascularization (TCAR), reimbursement has been limited to high-risk patients by the Centers for Medicare & Medicaid Services (CMS) since 2005. We aimed to assess the association of CMS high-risk status with perioperative outcomes for carotid endarterectomy (CEA), TFCAS, and TCAR. METHODS: We performed a retrospective review of all Vascular Quality Initiative patients who underwent carotid revascularization between 2015 and 2020. Patients were stratified by whether they met CMS CAS criteria, and univariable and multivariable logistic regression analyses were performed to assess the association of procedure type (CEA, TFCAS, TCAR) with perioperative outcomes. RESULTS: Of 124,531 individuals who underwent carotid revascularization procedures, 91,687 (73.6%) underwent CEA, 17,247 (13.9%) underwent TFCAS, and 15,597 (12.5%) underwent TCAR. Among patients who met the CMS CAS criteria (ie, high-risk patients), the incidence of perioperative stroke was 2.7% for CEA, 3.4% for TFCAS, and 2.4% for TCAR (P < .001). Among standard-risk patients, the incidence of perioperative stroke was 1.7% for CEA, 2.7% for TFCAS, and 1.8% for TCAR (P < .001). After adjusting for baseline demographic and clinical characteristics, the odds of perioperative stroke were lower for TCAR versus CEA in high-risk patients (adjusted odds ratio [aOR], 0.82; 95% confidence interval [CI], 0.68-0.99) and similar in standard-risk patients (aOR, 1.05; 95% CI, 0.84, 1.31). In contrast, the adjusted odds of perioperative stroke were higher for TFCAS versus CEA in high-risk patients (aOR, 1.23; 95% CI, 1.03-1.46) and standard-risk patients (aOR, 1.60; 95% CI, 1.37-1.86). In both populations, TFCAS and TCAR patients had significantly lower odds of myocardial infarction than CEA patients (both P < .001). CONCLUSIONS: The perioperative risks associated with CEA, TFCAS, and TCAR in high-risk patients support the current CMS criteria, although the risks associated with each revascularization approach in standard-risk patients suggest that distinguishing TCAR from TFCAS may be warranted.

A systematic review of sutureless vascular anastomosis technologies.

Vascular anastomoses typically involve a handsewn technique requiring significant surgical training, expertise, and time. The aim of our systematic review was to identify and describe sutureless vascular anastomosis techniques. We performed a systematic review of all sutureless vascular anastomosis technologies published in MEDLINE, PubMed, Embase, CINAHL, Cochrane, Web of Science, and Scopus Library databases and a patent review using US Patent and Trade Office Application, US Patent and Trademark Office Patent, Google Patents, Lens, Patent Quality Through Artificial Intelligence, SureChEMBL, and E-Space Net. Data from inclusion studies and patents published between January 1, 1980 and July 15, 2021 were abstracted to describe their category, anastomosis type and configuration, study types, and advantages and disadvantages encountered with each technology. Two hundred eleven original studies and 475 patents describing sutureless vascular anastomosis technologies were identified. In the literature, stents/stent-grafts/grafts (n = 61), lasers (n = 53), and couplers (n = 27) were the predominant device categories. In the patent review, adhesive technologies (n = 103), stents/stent-grafts/grafts (n = 68), and mechanical connectors (n = 61) predominated. The majority of studies involved in vivo animal studies (n = 193); 32.2% (n = 68) of investigations involved human trials; and 17.9% (n = 85) of patent technologies were approved by the US Food and Drug Administration. The main advantages described for sutureless anastomosis technologies included faster procedure time and greater patency rates compared with handsewn anastomoses. The main disadvantages included reduced vessel compliance, stenosis, leakage, and device costs. The appeal of sutureless technology is substantiated by numerous animal trials, but their use in humans remains limited. This may be a reflection of strict regulatory criteria and/or vascular complications associated with currently available technologies.