Racial differences in utilization and outcomes of hemodialysis access in the Unites States.

OBJECTIVE: To evaluate patterns of use and outcomes of arteriovenous fistulas and prosthetic grafts within racial categories in a large population based cohort of hemodialysis (HD) patients in the United States. METHODS: A retrospective analysis of white, black, and Hispanic patients in the prospectively maintained United States Renal Database System who had an autogenous fistula or prosthetic graft placed for HD access between January 2007 and December 2014 was performed. Analysis of variance, χ2, t-tests, Kaplan-Meier, log-rank tests, multivariable logistic, and Cox regression analyses were used to evaluate maturation, patency, infection, and mortality. RESULTS: This study of 359,942 patients, composed of 285,781 autogenous fistulas (79.4%) and 74,161 prosthetic grafts (20.6%) placed in 213,877 white (59.4%), 115,727 black (32.2%), and 30,338 Hispanic (8.4%) patients. There was a 11% increase in the risk-adjusted odds of HD catheter use as bridge to autogenous fistula placement in blacks (adjusted odds ratio, 1.11; 95% confidence interval [CI], 1.08-1.14; P < .001) and a 9% increase in Hispanics (adjusted odds ratio, 1.09; 95% CI, 1.05-1.14; P < .001) compared with whites. Fistula maturation for HD access for whites vs blacks vs Hispanics was 77.0% vs 76.3% vs 77.8% (P = .35). After adjusting for covariates, fistula maturation was higher for blacks (adjusted hazard ratio, 1.09; 95% CI, 1.06-1.13; P < .001) and Hispanics (adjusted hazard ratio, 1.13; 95% CI, 1.06-1.20; P < .001) compared with whites. There was no significant difference in prosthetic graft maturation for blacks and Hispanics compared with whites. Primary, primary-assisted, and secondary patency were highest for Hispanic and least for black autogenous fistula recipients. Primary, primary-assisted, and secondary patency was also highest for Hispanic patients who received prosthetic grafts. Prosthetic grafts were associated with a decrease in patency and patient survival compared with fistulas in all racial categories. Mortality was lower for blacks and Hispanics relative to white patients. Initiation of HD with a catheter and conversion to autogenous fistula was associated with decrease in patency and patient survival compared with initiation with a fistula in all racial groups. CONCLUSIONS: Autogenous fistulas are associated with better patency and patient survival compared with prosthetic grafts for all races studied. The use of HD catheter before fistula placement is more prevalent in Hispanic and black patients and is associated with worse patency and patient survival irrespective of race. Fistula and graft patency is highest for Hispanic patients. Patient survival is higher for Hispanic and black patients relative to whites. These associations suggest potential benefit with initiation of HD via autogenous fistula and minimizing temporizing catheter use, irrespective of race.

Hemodynamic events during carotid stenting are associated with significant periprocedural stroke and adverse events.

BACKGROUND: There are limited data on the impact of carotid angioplasty and stenting (CAS)-related changes in blood pressure, heart rate, and preprocedural medications on periprocedural stroke in contemporary, real-world practice. This study evaluates the risk attributable to the CAS-related hemodynamic events and the impact preprocedural medications have on mitigating this risk in a large, population-based cohort. METHODS: We studied all patients in the Vascular Quality Initiative who underwent CAS between January 2006 and December 2016. Kaplan-Meier, multivariable logistic, and Cox regression analyses were used to evaluate the impact of periprocedural hypertension, hypotension, bradycardia, and medication use on immediate periprocedural stroke (IPPS), 30-day, and 1-year stroke. RESULTS: Of the 13,698 CAS procedures studied, 1239 (9.1%), 1824 (13.3%), and 1333 (9.7%) patients experienced periprocedural hypertension, hypotension, and bradycardia, respectively. IPPS was 3.2% vs 2.1% vs 0.65% (P < .001), comparing patients with periprocedural hypertension vs hypotension vs normotension and 1.4 vs 1.0% (P = .19) for bradycardic vs nonbradycardic patients. Periprocedural hypertension was associated with a four-fold increase in IPPS (adjusted odd ratio [aOR], 3.97; 95% confidence interval [CI], 2.63-5.99; P < .001). periprocedural hypotension and bradycardia were associated with 5.5-fold (aOR, 5.56; 95% CI, 3.24-9.52; P < .001) and 2.3-fold (aOR, 2.31; 95% CI, 1.26-4.25; P = .007) increases in IPPS among patients with carotid symptoms. There was 76% decrease in IPPS for patients who did not experience a periprocedural hemodynamic event (aOR, 0.24; 95% CI, 0.16-0.35; P < .001). Unlike preprocedural beta-blockers and angiotensin-converting enzyme inhibitors, prophylactic antibradyarrhythmic agents conferred a 58% reduction in IPPS among patients with carotid symptoms (aOR, 0.42; 95% CI, 0.23-0.78; P = .006). The periprocedural hemodynamic events were also associated with 7.7-fold increase in myocardial infarction (aOR, 7.70; 95% CI, 4.77-12.45; P < .001), a 2.2-fold increase in 30-day mortality (aOR, 2.24; 95% CI, 1.61-3.12; P < .001), and a 16% increase in length of stay (aOR, 1.16; 95% CI, 0.04-2.28; P = .042). The occurrence of these hemodynamic events is higher in patients with prior cardiac disease and the difference in periprocedural outcomes extended to 1 year. CONCLUSIONS: Periprocedural hemodynamic events are associated with an increase in periprocedural stroke, myocardial infarction, death, and length of stay. Periprocedural hypertension in all patients; hypotension and bradycardia in patients with symptomatic carotid disease are associated with significant increase in IPPS. Prophylactic antibradyarrhythmic agents are associated with decrease in bradycardia and IPPS. These results heighten the need to anticipate and promptly address these CAS-related hemodynamic events, especially in susceptible patients.

Xanthine Oxidoreductase Function Contributes to Normal Wound Healing.

Chronic, nonhealing wounds result in patient morbidity and disability. Reactive oxygen species (ROS) and nitric oxide (NO) are both required for normal wound repair, and derangements of these result in impaired healing. Xanthine oxidoreductase (XOR) has the unique capacity to produce both ROS and NO. We hypothesize that XOR contributes to normal wound healing. Cutaneous wounds were created in C57Bl6 mice. XOR was inhibited with dietary tungsten or allopurinol. Topical hydrogen peroxide (H2O2, 0.15%) or allopurinol (30 µg) was applied to wounds every other day. Wounds were monitored until closure or collected at d 5 to assess XOR expression and activity, cell proliferation and histology. The effects of XOR, nitrite, H2O2 and allopurinol on keratinocyte cell (KC) and endothelial cell (EC) behavior were assessed. We identified XOR expression and activity in the skin and wound edges as well as granulation tissue. Cultured human KCs also expressed XOR. Tungsten significantly inhibited XOR activity and impaired healing with reduced ROS production with reduced angiogenesis and KC proliferation. The expression and activity of other tungsten-sensitive enzymes were minimal in the wound tissues. Oral allopurinol did not reduce XOR activity or alter wound healing but topical allopurinol significantly reduced XOR activity and delayed healing. Topical H2O2 restored wound healing in tungsten-fed mice. In vitro, nitrite and H2O2 both stimulated KC and EC proliferation and EC migration. These studies demonstrate for the first time that XOR is abundant in wounds and participates in normal wound healing through effects on ROS production.

Contemporary outcomes of intact and ruptured visceral artery aneurysms.

OBJECTIVE: The treatment outcomes of ruptured visceral artery aneurysms (rVAAs) have been sparsely characterized, with no clear comparison between different treatment modalities. The purpose of this paper was to review the perioperative and long-term outcomes of open and endovascular interventions for intact visceral artery aneurysms (iVAAs) and rVAAs. METHODS: This was a retrospective review of all treated VAAs at one institution from 2003 to 2013. Patient demographics, aneurysm characteristics, management, and subsequent outcomes (technical success, mortality, reintervention) and complications were recorded. RESULTS: The study identified 261 patients; 181 patients were repaired (77 ruptured, 104 intact). Pseudoaneurysms were more common in rVAAs (81.8% vs 35.3% for iVAAs; P < .001). The rVAAs were smaller than the iVAAs (20.7 mm vs 27.5 mm; P = .018), and their most common presentation was abdominal pain; 29.7% were hemodynamically unstable. Endovascular intervention was the initial treatment modality for 67.4% (75.3% for rVAAs, 61.5% for iVAAs). The perioperative complication rate was higher for rVAAs (13.7% vs 1% for iVAAs; P = .003), as was mortality at 30 days (13% vs 0% for iVAAs; P = .001), 1 year (32.5% for rVAAs vs 4.1% for iVAAs; P < .001), and 3 years (36.4% for rVAAs vs 8.3% for iVAAs; P < .001). Lower 30-day mortality was noted with endovascular repair for rVAAs (7.4% vs 28.6% open; P = .025). Predictors of mortality for rVAAs included age (odds ratio, 1.04; P = .002), whereas endovascular repair was protective (odds ratio, 0.43; P = .037). Mean follow-up was 26.2 months, and Kaplan-Meier estimates of survival were higher for iVAAs at 3 years (88% vs 62% for rVAAs; P = .045). The 30-day reintervention rate was higher for rVAAs (7.7% vs 19.5% for iVAAs; P = .019) but was similar between open and endovascular repair (8.2% vs 15%; P = NS). CONCLUSIONS: rVAAs have significant mortality. Open and endovascular interventions are equally durable for elective repair of VAAs, but endovascular interventions for rVAAs result in lower morbidity and mortality. Aggressive treatment of pseudoaneurysms is electively recommended at diagnosis regardless of size.

Evolution of treatment for traumatic thoracic aortic injuries.

OBJECTIVE: To review the evolution of traumatic thoracic aortic injury (TTAI) treatment at a single institution. METHODS: Retrospective analysis of all patients included in an institutional trauma registry and vascular surgery database who underwent treatment of TTAI between January 1999 and January 2011. RESULTS: Ninety-one patients (69 males) were treated for TTAI. The mean age was 38.5 years (range, 16-79 years). Forty-one patients underwent open repair (OR) and 50 thoracic endovascular repair (TEVAR), 37 with thoracic stent grafts (TSG) alone, 11 with infrarenal aortic extender cuffs (AEC), and two with a combination of TSG and AEC. OR was performed exclusively until 2004; the last one was performed in January 2007. All TTAIs have since been treated with TEVAR. The left subclavian artery (LSA) was fully covered in 10 patients (20%) and partially covered in eight patients, with revascularization in only two cases. The use of AEC and avoidance of LSA coverage increased after 2007. Baseline characteristics and injury severity scores were similar between groups. The mortality rate was higher in the OR group (19.5% vs 6.0%; P = .06), although it did not reach statistical significance. The overall incidence of morbidities was similar between the two groups (42% OR vs 50% TEVAR). Two patients developed paraplegia (4.4%) after OR compared with none after TEVAR. In the TEVAR group, a pseudoaneurysm, an iliac artery thrombosis, and a retroperitoneal hematoma developed in one patient each. Overall, eight patients (16%) developed stent graft-related complications (SRC), with two developing early (within 30 days) complications. All complications were related to poor apposition, requiring 10 reinterventions. Four patients underwent open conversions with no mortality. Nine out of 10 SRCs were associated with the use of thoracic stent graft malapposition. No patient treated with AEC had endoleaks or SRC. CONCLUSIONS: TEVAR for TTAI has superior survival outcomes and has replaced OR. SRC requiring reintervention is associated with malapposition and the use of TSG. Until TTAI-specific endografts become available, use of AEC may minimize malapposition and reduce reinterventions. Routine overstenting of the LSA is not necessary and may increase SRC.

Virtual medical student education and recruitment during the COVID-19 pandemic.

Due to the immediate need for social distancing, as well as widespread disruption in clinical practices, brought on by the novel severe acute respiratory syndrome coronavirus 2 (COVID-19) pandemic, medical student education rapidly shifted to a virtual format, which resulted in a variety of innovative and remotely accessible practices to address new restrictions on face-to-face education. Educators approached curriculum design seeking to replicate as much of the in-person experience as possible, and were faced with overcoming the challenges of replacing the innately hands-on nature of surgery with virtual operative and skills experiences. Restrictions on in-person visiting electives expedited the role of virtual education as a notable opportunity for medical student education and recruitment, with a variety of approaches to engaging undergraduate medical learners, including the use of live-streaming operative cases, virtual didactic curricula, and a rise in podcasts; web-based conferences; and virtual journal clubs. In addition to education, virtual outreach to medical students has become an essential tool in trainee recruitment and selection, and ongoing application of novel educational platforms will allow for new opportunities in multi-institutional collaboration and exchange with a multitude of benefits to future vascular surgery trainees. Our aim was to outline the resources and practices used to virtually teach and recruit medical students and the benefits of virtual rotations to the program and students.