Aortobifemoral bypass vs covered endovascular reconstruction of aortic bifurcation.

BACKGROUND: Covered endovascular reconstruction of aortic bifurcation (CERAB) is increasingly used as a first line-treatment in patients with aortoiliac occlusive disease (AIOD). We sought to compare the outcomes of patients who underwent CERAB compared with the gold standard of aortobifemoral bypass (ABF). METHODS: The Vascular Quality Initiative was queried for patients who underwent ABF or CERAB from 2009 to 2021. Propensity scores were generated using demographics, comorbidities, Rutherford class, and urgency. The two groups were matched using 5-to-1 nearest-neighbor match. Our primary outcomes were 1-year estimates of primary patency, major adverse limb events (MALEs), MALE-free survival, reintervention-free survival, and amputation-free survival. Standard statistical methods were used. RESULTS: A total of 3944 ABF and 281 CERAB cases were identified. Of all patients with AIOD, the proportion of CERAB increased from 0% to 17.9% between 2009 and 2021. Compared with ABF, patients who underwent CERAB were more likely to be older (64.7 vs 60.2; P < .001) and more often had diabetes (40.9% vs 24.1%; P < .001) and end-stage renal disease (1.1% vs 0.3%; P = .03). In the matched analysis (229 CERAB vs 929 ABF), ABF patients had improved MALE-free survival (93.2% [±0.9%] vs 83.2% [±3%]; P < .001) and lower rates of MALE (5.2% [±0.9%] vs 14.1% [±3%]; P < .001), with comparable primary patency rates (98.3% [±0.3%] vs 96.6% [±1%]; P = .6) and amputation-free survival (99.3% [±0.3%] vs 99.4% [±0.6%]; P = .9). Patients in the CERAB group had significantly lower reintervention-free survival (62.5% [±6%] vs 92.9% [±0.9%]; P < .001). Matched analysis also revealed shorter length of stay (1 vs 7 days; P < .001), as well as lower pulmonary (1.2% vs 6.6%; P = .01), renal (1.8% vs 10%; P < .001), and cardiac (1.8% vs 12.8%; P < .001) complications among CERAB patients. CONCLUSIONS: CERAB had lower perioperative morbidity compared with ABF with a similar primary patency 1-year estimates. However, patients who underwent CERAB experienced more major adverse limb events and reinterventions. Although CERAB is an effective treatment for patients with AIOD, further studies are needed to determine the long-term outcomes of CERAB compared with the established durability of ABF and further define the role of CEARB in the treatment of AIOD.

Incidence and Outcomes of Visceral Ischemia in Acute Aortic Occlusion.

BACKGROUND: Acute aortic occlusion (AAO) is a morbid diagnosis in which mortality correlates with severity of ischemia on presentation. Visceral ischemia (VI) is challenging to diagnose and its presentation as a consequence of AAO is not well-studied. We aim to identify characteristics associated with VI in AAO to facilitate diagnosis. METHODS: Patients diagnosed with AAO who underwent revascularization were identified retrospectively from institutional records (2006-2020). The primary outcome was the development of VI (intra-abdominal ischemia). Univariate analysis was used to compare demographic, exam, imaging, and intraoperative variables between patients with and without VI in the setting of AAO. RESULTS: Ninety-one patients were included. The prevalence of VI was 20.9%. Preoperative comorbidities, time to revascularization, and operative approach did not differ between patients with and without VI. Patients with VI more frequently were transferred from outside institutions (100% vs. 53%, P = 0.02), presented with advanced acute limb ischemia (Rutherford III 36.9% vs. 7.5%, P < 0.01), and had elevated preoperative serum lactate (4.31 vs. 2.41 mmol/L, P < 0.01). VI patients had an increased occurrence of bilateral internal iliac artery (IIA) occlusion (47.4% vs. 18.1%, P = 0.01). Unilateral IIA occlusion, level of aortic occlusion, and patency of inferior mesenteric arteries were not associated with VI. Patients with VI had worse postoperative outcomes. In particular, VI conferred significant risk of mortality (odds ratio 5.45, P < 0.01). CONCLUSIONS: Visceral ischemia is a common consequence of AAO. Elevated lactate, bilateral IIA occlusion, and advanced acute limb ischemia (ALI) should increase clinical suspicion for concomitant VI with AAO and may facilitate earlier diagnosis to improve outcomes.

Trends in Utilization of Completion Imaging after Lower Extremity Bypass and Its Association with Major Adverse Limb Events and Loss of Primary Patency.

BACKGROUND: Failure following lower extremity bypasses (LEBs) isoften secondary to technical defects. Despite traditional teachings, routine use of completion imaging (CI) in LEB has been debated. This study assesses national trends of CI following LEBs and the association of routine CI with 1-year major adverse limb events (MALE) and 1-year loss of primary patency (LPP). METHODS: The Vascular Quality Initiative (VQI) LEB dataset from 2003-2020 was queried for patients who underwent elective bypass for occlusive disease. The cohort was divided based on surgeons' CI strategy at time of LEB, categorized as routine (≥80% of cases/year), selective (<80% of cases/year), or never. The cohort was further stratified by surgeon volume category [low (<25th percentile), medium (25th-75th percentile), or high (>75th percentile)]. The primary outcomes were 1-year MALE-free survival and 1-year loss of primary patency (LPP)-free survival. Our secondary outcomes were temporal trends in CI use and temporal trends in 1-year MALE rates. Standard statistical methods were utilized. RESULTS: We identified 37,919 LEBs; 7,143 in routine CI strategy cohort, 22,157 selective CI and 8,619 in never CI. Patients in the 3 cohorts had comparable baseline demographics and indications for bypass. There was a significant decrease in CI utilization from 77.2% in 2003 to 32.0% in 2020 (P < 0.001). Similar trends in CI use were observed in patients who underwent bypass to tibial outflows (86.0% in 2003 vs. 36.9% in 2020; P < 0.001). While the use of CI has decreased over time, 1-year MALE rates have increased from 44.4% in 2003 to 50.4% in 2020 (P < 0.001). On multivariate COX regression, however, no significant associations between CI use or CI strategy and risk of 1-year MALE or LPP was found. Procedures performed by high-volume surgeons carried a lower risk of 1-year MALE (HR: 0.84; 95% CI [0.75-0.95]; P = 0.006) and LPP (HR:0.83; 95% CI [0.71-0.97]; P < 0.001) compared to low-volume surgeons. Repeat adjusted analyses showed no association between CI (use or strategy) and our primary outcomes when the subgroups with tibial outflows were analyzed. Similarly, no associations were found between CI (use or strategy) and our primary outcomes when the subgroups based on surgeons' CI volume were evaluated. CONCLUSIONS: The use of CI, for both proximal and distal target bypasses, has decreased over time while 1-year MALE rates have increased. Adjusted analyses indicate no association between CI use and improved MALE or LPP survival at 1 year and all CI strategies were found to have equivalent outcomes.

Stenting performs better than drug-coated balloon angioplasty in popliteal lesions.

BACKGROUND: Peripheral arterial disease (PAD) is a common and highly morbid disease. Although there have been recent advancements in the endovascular modalities to treat PAD, comparisons of these strategies, especially in the popliteal region, remain underinvestigated. The objective of this study was to compare midterm outcomes in patients with PAD undergoing treatment with both novel and SS compared with drug-coated balloon (DCB) angioplasty. METHODS: All patients at a multi-institution health system treated for PAD in the popliteal region from 2011 to 2019 were identified. Presenting features, operative details, and outcomes were included in the analysis. Patients who underwent popliteal revascularization with stents were compared with DCB. SS were compared separately with novel dedicated stents. Two-year primary patency was the primary outcome. RESULTS: We included 408 patients (72.7 ± 11.8 years old; 57.1% men) in the analysis. There were 221 (54.7%) patients who underwent popliteal stenting and 187 (45.3%) who underwent popliteal DCB. There were high rates of tissue loss in both groups (57.9% vs 50.8%; P = .14). Stented patients had longer lesions (112.4 ± 3.2 vs 100.2 ± 5.8 mm; P = .03) and higher rates of concomitant superficial femoral artery treatment (88.2% vs 39.6%; P < .01). Chronic total occlusions accounted for the majority of lesions treated (stent 62.4%, DCB 64.2%). Perioperative complications were similar between groups. Primary patency for the stented group was higher at two years than the DCB group (61.0% vs 46.1%; P = .03). When evaluating stented patients only, SS had higher 2-year patency than novel stents in the popliteal segment (69.6% vs 51.4%; P = .04). On multivariable analysis, stenosis, as opposed to chronic total occlusion, was associated with improved patency (hazard ratio, 0.49; 95% confidence interval, 0.25-0.96; P = .04), whereas novel stents were associated with worse primary patency (hazard ratio, 2.01; 95% confidence interval, 1.09-3.73; P = .03). CONCLUSIONS: In a population of patients with severe vascular disease, stents do not have inferior patency and limb salvage rates compared with DCB angioplasty when treating the popliteal region. For patients with advanced vascular disease, and especially tissue loss, stents and DCB are both beneficial when treating popliteal lesions.

Improved outpatient medical visit compliance with sociodemographic discrepancies in vascular telehealth evaluations.

OBJECTIVE: The COVID-19 (coronavirus disease 2019) pandemic has led to a rapid expansion in the use of telemedicine across all medical fields but has also exposed telehealth care disparities with differing access to technology across racial and ethnic groups. The objective of our study was to investigate the effects of telehealth on vascular visit compliance and to explore the effects of sociodemographic factors on vascular surgery outpatient telehealth usage during the COVID-19 pandemic. METHODS: Consecutive patients who had undergone an outpatient vascular surgery evaluation between February 24, 2020 (the launch of our telemedicine program) and December 31, 2020, were reviewed. The baseline demographic and outcomes were obtained from the electronic medical records. Telehealth and in-person evaluations were defined according to the patient's index visit during the study period. Medical visit compliance was established on completion of the telehealth or in-person encounter. We used χ2 tests and logistic regression analyses. RESULTS: A total of 23,553 outpatient visits had been scheduled for 10,587 patients during the study period. Of the outpatient visits, 1559 had been scheduled telehealth encounters compared with 21,994 scheduled in-person encounters. Of the scheduled outpatient encounters, 13,900 medical visits (59.0%) had been completed: 1183 telehealth visits and 12,717 in-person visits. The mean travel distance saved for the telehealth visits was 22.1 ± 27.1 miles, and the mean travel time saved was 46.3 ± 41.47 minutes. We noted no sociodemographic differences between the patients scheduled for telehealth vs in-person visits. We found a trend toward a lower proportion of African-American patients in the telehealth group vs the in-person group (7.8% vs 10.6%; P = .116), without statistical significance. A significantly higher rate of medical visit completion was found for the telehealth group compared with the in-person group (79.5% vs 59.4%; P < .001). Among the patients scheduled for an outpatient medical visit, a scheduled telemedicine evaluation (vs in-person) was associated with 2.3 times the odds of completing the medical visit (odds ratio, 2.31; 95% confidence interval, 2.05-2.61), adjusting for age, sex, race, ethnicity, language, and the distance between the patient's home zip code and the outpatient vascular center's zip code. Selecting for scheduled telemedicine visits, African-American race was associated with a decreased odds of telemedicine usage (odds ratio, 0.73; 95% confidence interval, 0.59-0.90) after adjusting for age, sex, ethnicity, language, and visit type. CONCLUSIONS: Use of the vascular surgery outpatient telehealth evaluation appeared to improve medical visit completion in our region with apparent sociodemographic disparities. Further studies are needed to confirm whether telemedicine expansion has improved access to care in other geographic areas.

Alternative autologous and biologic conduits have worse outcomes than prosthetic grafts for infrainguinal bypass in patients with chronic limb-threatening ischemia.

OBJECTIVE: Single segment great saphenous vein (GSV) is the preferred conduit in infrainguinal bypass. Alternative autologous conduits (AAC) and nonautologous biologic conduits (NABC) are thought to be a better alternative to traditional prosthetic conduits (PC) in the absence of GSV. In this study we analyzed the outcomes of these alternative conduits in lower extremity bypasses (LEB) in patients with chronic limb-threatening ischemia. METHODS: The Vascular Quality Initiative LEB database from 2003 to 2020 was queried for this study, to identify LEB in patients with chronic limb-threatening ischemia. Primary outcomes were graft patency, major adverse limb events (MALE), and MALE-free survival at 1 year. Standard statistical methods were used as appropriate. RESULTS: We identified 22,671 LEB procedures (12,810 GSV, 6002 PC, 1907 AAC, and 1952 NABC). Compared with the GSV group, the other conduit patients were significantly older, had more comorbidities, had an increased rate of prior lower extremity interventions, had a higher rate of infrageniculate bypass targets, and were less ambulatory at baseline. The PC, AAC, and NABC groups had significantly higher rates of postoperative morbidity compared with the GSV group. The PC group had a higher 30-day mortality compared with the GSV, AAC, and NABC groups (3% PC vs 2% GSV, 2% AAC, 2% NABC; P = .049). Both PC and NABC had higher 1-year mortality compared with GSV and AAC (13% PC and 13% NABC vs 10% GSV, 10% AAC; P = .02). In an adjusted Cox regression model (stratified by infrageniculate target and adjusted for age, comorbidities, and prior vascular interventions) PC was not significantly different from GSV, but AAC (hazard ratio [HR], 1.41; 95% confidence interval [CI], 1.19-1.67; P < .001) and NABC (HR, 1.9; 95% CI, 1.61-2.25; P < .001) were associated with an increased risk of loss of primary patency. A similar association with MALE was observed: both AAC (HR, 1.35; 95% CI, 1.15-1.58; P < .001) and NABC (HR, 1.8; 95% CI, 1.53-2.11; P < .001) were associated with an increased risk of MALE compared with GSV; PC was not significantly different from GSV. CONCLUSIONS: In the absence of GSV, alternative conduits (autologous or nonautologous biologic) do not confer a benefit with regard to graft patency or MALE compared with PCs. Increased operating time or costs associated with the use of these conduits is not justified based on this study.

Partial Claviculectomy to Relieve Tracheal Compression in an Adult Male with Osteomesopyknosis.

BACKGROUND: The clavicle is a long bone that forms the anterior border of the thoracic inlet. Anatomic abnormalities of the clavicle can lead to compression of the innominate artery and trachea due to mass effect. These anatomic abnormalities can be amenable to surgical resection, which can provide complete resolution of symptoms. METHODS: We present a case of tracheal compression by the innominate artery in an adult man, caused by a clavicular abnormality due to an underlying bone mineralization disorder, corrected by partial resection of the right clavicle. RESULTS: The patient underwent successful open surgical resection of his right clavicular head leading to resolution of his tracheal compression by the innominate artery. CONCLUSIONS: We believe that this is the first description of tracheal compression due to osteomesopyknosis. This case demonstrates that compression of the innominate artery due to a clavicular abnormality can be safely corrected via open surgical resection.

Improving Code Status Documentation Rates Using Communication Skills Training in Vascular Surgery: A Quality Improvement Initiative.

Introduction: Code status discussions are poorly understood by patients and variably performed by admitting providers, yet they are used as a quality metric. Surgical specialties, such as Vascular Surgery, admit patients with urgent and life-threatening illness. Surgical trainees are less likely to receive communication skills interventions when compared with nonsurgical specialties. Without a documented code status, nurses and physicians lack guidance on patient preference in the case of cardiopulmonary arrest and may deliver unwanted measures, which may also result in poor outcomes. Methods: We conducted a before-after Plan-Do-Study-Act quality improvement project between May 2018 and May 2019. A needs assessment included baseline code status documentation rates for the Vascular Surgery department admissions. A communication skills training (CST) and documentation intervention was provided to all Vascular Surgery trainees and advance practice providers (APPs). Departmental e-mails were sent over the 12-month intervention period, which demonstrated the code status documentation rates and served as reminders to document code status. Results: A total of 29 vascular surgery trainees and APPs received the intervention. At completion of the intervention, learners reported increased comfort initiating a code status discussion, making a recommendation for cardiopulmonary resuscitation (CPR) status, and having a strategy to discuss code status. A total of 2762 patient admissions were reviewed, with 1562 patient admissions occurring during the 12-month intervention period. The average code status documentation rate for the three months before the intervention was 7.8%. At the end of the 12-month intervention, documentation rates were 44.9% and 6 months after completion of the study period, average rates remained 45.2%. There was no change in admission rates during the study period. Discussion: CST and regular reminders increased vascular surgery residents' and APPs' comfort in engaging in code status discussions. After intervention, documentation of code status discussions increased with persistence up to six months after the intervention.

Any Postoperative Surveillance Improves Survival after Endovascular Repair of Ruptured Abdominal Aortic Aneurysms.

BACKGROUND: Endovascular aortic repair (EVAR) has advanced the care of patients with ruptured abdominal aortic aneurysms (rAAA) with improved early postoperative morbidity and mortality. However, this comes at the cost of a rigorous postoperative surveillance schedule to monitor for further aneurysmal degeneration. Adherence to surveillance recommendations is known to be poor in the elective setting, but has yet to be studied in the ruptured population. The aim of this study is to investigate predictors of incomplete surveillance after EVAR for rAAA (rEVAR) and examine how adherence impacts outcomes. METHODS: This was a retrospective case control study of patients undergoing rEVAR at a multiple hospital single healthcare center (2003-2020). Patients were excluded if they underwent open conversion during their index hospitalization or died within 60 days of surgery. Follow-up was broadly categorized as complete surveillance (60-day postoperative visit and annually thereafter) or incomplete surveillance, comprising both patients with less than recommended surveillance (minimal surveillance) and completely lost to follow-up (LTF). Any follow-up was defined as patients with complete or minimal surveillance. We investigated predictors of complete versus incomplete surveillance by multivariate logistic regression. Secondary outcomes included overall survival and cumulative incidence of reintervention controlling for the competing risk of mortality, generating hazard ratios (HR) and subdistribution hazard ratios (SHR). RESULTS: One-hundred and sixty patients (mean age 74 ± 10.1 years, 81.2% male) out of 673 total rAAA met study inclusion criteria. Complete surveillance was seen in 41.3% of our cohort, with the remainder with minimal surveillance (29.4%) or LTF (29.4%). Incomplete surveillance was associated with male sex (odds ratio [OR] 2.56; 95% CI 1.02-6.43), lack of a primary care provider (PCP; OR 0.20; 95% CI 0.04-0.99), and longer driving distance from home to treating hospital (OR 2.37; 95% CI 1.08-5.20). Survival was not different between complete and incomplete surveillance groups, however any follow-up conferred improved survival over LTF (HR 0.57; 95% CI 0.331-0.997; P = 0.049). Reintervention was associated with incomplete surveillance (SHR 0.29; 95% CI 0.11-0.75), and discharge to a facility (SHR 0.25; 95% CI 0.067-0.94). CONCLUSIONS: Incomplete surveillance was observed in over 50% of patients who underwent rEVAR and was associated with male sex, lack of PCP, and longer driving distance. Any follow-up conferred a survival benefit, yet incomplete surveillance was associated with a lower risk of reintervention. Targeted strategies to prevent LTF, and less stringent, personalized follow-up plans that may confer similar survival benefit with better patient adherence should be investigated.

Complete Venous Ulceration Healing after Perforator Ablation Does Not Depend on Treatment Modality.

BACKGROUND: Venous leg ulceration (VLU) represents the most advanced form of chronic venous insufficiency (CVI). Persistent VLU that fails to respond to noninvasive treatment requires a minimally invasive endovascular treatment, which may include chemical (ultrasound-guided foam sclerotherapy [UGFS]) and thermal ablation (endovenous laser therapy [EVLT] or radiofrequency ablation [RFA]) targeting incompetent veins. Current guidelines suggest ablation of incompetent perforating veins (IPVs) juxtaposed to active or healed VLU; however, the ideal treatment modality is unknown. We hypothesize that similar to incompetent superficial vein treatment options therapies, VLU healing will be equivalent across minimally invasive IPV treatment options. METHODS: Using the Vascular Low Frequency Disease Consortium, adults with VLU across 11 medical centers were retrospectively reviewed (2013-2017). We included those who underwent IPV therapies. The primary outcome was complete ulcer healing over time compared with cumulative hazard curves, log-rank testing, and multivariable Cox proportional hazard regression. Secondary outcomes included number of subsequent procedures, which were compared using negative binomial regression. RESULTS: Of the 832 adults with VLU, 158 (19%) were exclusively treated conservatively, and 232 (28%) underwent index treatment for IPV and constitute the full and final cohort. The mean age was 60 ± 14 years, 57% were men, and the mean ulcer area was 3.0 cm2 (interquartile range, 1-6 cm2). Ninety-one (39%) were treated with EVLT, 127 (55%) RFA, and 14 (6%) UGFS. Patients treated with RFA were older (RFA 62 ± 14 years; EVLT 59 ± 14 years; UGFS 52 ± 9 years; P = 0.01), more likely to be men (RFA 68%, n = 86; EVLT 41%, n = 37; UGFS 64%, n = 9; P < 0.001), with a higher frequency of anticoagulation (RFA 36%, n = 46; EVLT 18%, n = 16; UGFS 14%, n = 2; P = 0.005). VLU did not significantly differ in size between groups (RFA 6.2 ± 8; EVLT 4.2 ± 5.4; UGFS 6.1 ± 8; P < 0.001). There were no differences in 1-year ulcer healing rates between groups (P = 0.18). The number of subsequent procedures did not differ by treatment modality (P = 0.47). CONCLUSIONS: This multi-institutional retrospective study does not demonstrate any association of IPV treatment modality with differing rates of VLU healing or number of subsequent procedures.

Risk factors for acute kidney injury after pharmacomechanical thrombolysis for acute deep vein thrombosis.

BACKGROUND: Pharmacomechanical thrombolysis (PMT) is an established treatment for selected patients with acute deep vein thrombosis (DVT). Despite significant clinical success, hemolysis can lead to acute kidney injury (AKI) with unknown longer term implications. Our aim was to characterize the rate of AKI after PMT and identify those patients at the greatest risk. METHODS: A retrospective medical record review of patients with acute DVT who had undergone PMT in our institution from 2007 to 2018 was performed. The baseline demographics, comorbidities, preoperative clinical characteristics, procedural details, postoperative hospital course, and follow-up data were reviewed. The primary outcome was postoperative AKI (≥1.5 times preoperative creatinine), and longer term renal impairment. Logistic regression modeling was used to identify associated factors. RESULTS: A total of 137 patients (mean age, 47 ± 16.6 years; 49.6% male) who had undergone PMT for treatment of acute DVT were identified (85.4% AngioJet system; Boston Scientific Corp, Marlborough, Mass). Of the 137 patients, 30 (21.9%) had developed AKI in the periprocedural period, 1 of whom had required hemodialysis in the perioperative period. The patients who had developed AKI had had significantly greater rates of preoperative coronary artery disease (23.1% vs 4.7%; P = .002), diabetes mellitus (19.2% vs 6.6%; P = .045), dyslipidemia (42.3% vs 17.9%; P = .008), and hypertension (53.6% vs 29.3%; P = .018). No significant difference was found in preoperative creatinine (0.99 vs 0.92 mg/dL; P = .65) or glomerular filtration rate (GFR; 96.9 vs 91.8 mL/min; P = .52) between the two groups. Multivariate analysis demonstrated bilateral DVT (odds ratio [OR], 4.35; 95% confidence interval [CI], 1.47-12.86; P = .008), single-session PMT (OR, 3.05; 95% CI, 1.02-9.11; P = .046), and female sex (OR, 2.85; 95% CI, 1.01-8.04; P = .048) were significant predictors of AKI. Of the 30 patients, 10 had had normal renal function at discharge and 15 and 25 patients had had normal renal function at the first and subsequent clinical follow-up visits, respectively. The remaining five patients (3.6%) had progressed to moderate (GFR, <60 mL/min) or severe (GFR, <30 mL/min) renal insufficiency, with one requiring long-term hemodialysis. CONCLUSIONS: The use of PMT for treatment of acute DVT conferred a risk of AKI that will progress to chronic renal failure in a small fraction of affected patients. Patients with bilateral extensive DVTs have a greater risk of AKI; thus, longer priming with a thrombolytic drip before PMT should be preferred for this population.

EVAR: Open Surgical Repair Options for Persistent Type Ia Endoleaks.

Abdominal aortic aneurysm (AAA) is a disease of the elderly which may result in aneurysm rupture if not treated in a timely manner. The incidence of AAA has increased in part due to patient and physician education, ultrasound screening, and liberal use of computed tomography imaging in conjunction with an aging population. Endovascular aneurysm repair has become the preferred treatment for surgeons and interventionalists. When endografts are placed outside of device-specific instructions for use, the risk of endoleak development is significantly increased. Open surgical repair of Type Ia endoleaks is recommended when endovascular options have been exhausted. Open surgical repair of Type Ia endoleaks provides acceptable perioperative morbidity and mortality rates, long-term durability, and low reintervention rates when performed in the elective setting.

Dynamic Luminal Topography: A Potential Strategy to Prevent Vascular Graft Thrombosis.

AIM: Biologic interfaces play important roles in tissue function. The vascular lumen-blood interface represents a surface where dynamic interactions between the endothelium and circulating blood cells are critical in preventing thrombosis. The arterial lumen possesses a uniform wrinkled surface determined by the underlying internal elastic lamina. The function of this structure is not known, but computational analyses of artificial surfaces with dynamic topography, oscillating between smooth and wrinkled configurations, support the ability of this surface structure to shed adherent material (Genzer and Groenewold, 2006; Bixler and Bhushan, 2012; Li et al., 2014). We hypothesized that incorporating a luminal surface capable of cyclical wrinkling/flattening during the cardiac cycle into vascular graft technology may represent a novel mechanism of resisting platelet adhesion and thrombosis. METHODS AND RESULTS: Bilayer silicone grafts possessing luminal corrugations that cyclically wrinkle and flatten during pulsatile flow were fabricated based on material strain mismatch. When placed into a pulsatile flow circuit with activated platelets, these grafts exhibited significantly reduced platelet deposition compared to grafts with smooth luminal surfaces. Constrained wrinkled grafts with static topography during pulsatile flow were more susceptible to platelet accumulation than dynamic wrinkled grafts and behaved similar to the smooth grafts under pulsatile flow. Wrinkled grafts under continuous flow conditions also exhibited marked increases in platelet accumulation. CONCLUSION: These findings provide evidence that grafts with dynamic luminal topography resist platelet accumulation and support the application of this structure in vascular graft technology to improve the performance of prosthetic grafts. They also suggest that this corrugated structure in arteries may represent an inherent, self-cleaning mechanism in the vasculature.

Maturation of arteriovenous fistulas in patients with ventricular assist devices.

OBJECTIVE: Postoperative renal dysfunction necessitating hemodialysis after implantation of ventricular assist devices presents a challenge with respect to establishment of hemodialysis access. Lack of pulsatile flow has led to concerns that arteriovenous fistulas will not mature. This study aims to evaluate arteriovenous fistula as a method of hemodialysis. METHODS: Consecutive patients who underwent implantation of a ventricular assist device between 1988 and 2016 with a subsequent need for hemodialysis were identified. Retrospective data were collected for patients requiring hemodialysis through an arteriovenous fistula or arteriovenous graft. Access flow rates and duration of patency are reported. RESULTS: Sixty-four patients were identified (10 required long-term hemodialysis, 5 via arteriovenous fistula, 1 via arteriovenous graft). All six patients receiving long-term hemodialysis access were on continuous-flow ventricular assist devices. Brachiocephalic arteriovenous fistulas were performed in all arteriovenous fistula patients, and the average preoperative vein diameter was 4.1 ± 0.9 mm. On 30-day follow-up, the average flow rate was 1262 ± 643 mL/min (880-2220). In arteriovenous fistula patients, one died at 30 days, one arteriovenous fistula required ligation for steal syndrome at 5 months, and one was abandoned after 10.7 months for low flow. Of remaining fistulas, one was converted to an arteriovenous graft at 1.7 years for malfunction (with 5.3 month patency), and one remains open at 4.0 years. CONCLUSION: Arteriovenous fistulas should be considered in selected patients with ventricular assist devices as a means of long-term hemodialysis access to avoid use of catheters. Maturation and usage of primary arteriovenous fistulas is possible despite lack of pulsatile flow.

Systemic vasoprotection by inhaled carbon monoxide is mediated through prolonged alterations in monocyte/macrophage function.

Carbon monoxide (CO) is anti-inflammatory and protective in models of disease. Its actions in vitro are short-lived but are sustained in vivo. We hypothesize that systemic CO can mediate prolonged phenotype changes in vivo, with a focus on macrophages (Mφs). Mφs isolated from CO treated rats responded to lipopolysaccharide (LPS) with increased IL6, IL10 and iNOS expression but decreased TNF. Conditioned media (CM) collected from peritoneal Mφs isolated from CO treated rats stimulated endothelial cell (EC) proliferation versus CM from Mφs from air treated rats. This effect was mediated by Mφ released VEGF and HMGB1. Inhaled CO reduced LPS induced Mφ M1 inflammatory phenotype for up to 5 days. Mitochondrial oxygen consumption in LPS treated Mφs from CO treated mice was preserved compared to LPS treated Mφs from control mice. Finally, transient reduction of inflammatory cells at the time of inhaled CO treatment eliminated the vasoprotective effect of CO in a rodent carotid injury model. Thus, inhaled CO induces a prolonged mixed phenotype change in Mφs, and potentially other inflammatory cells, that contribute to vasoprotection. These findings demonstrate the ability of inhaled CO to modify Mφs in a sustained manner to mediate its therapeutic actions, supporting the translational potential of inhaled CO.

Outcomes of left renal vein stenting in patients with nutcracker syndrome.

BACKGROUND: Nutcracker syndrome (NCS) is a rare condition that can be manifested with hematuria, flank pain, pelvic varicosities, or chronic pelvic congestion related to left renal vein (LRV) compression. Open surgery, specifically LRV transposition, has been the mainstay of treatment, but in the past few years, LRV stenting has emerged as a less invasive alternative without sufficient evidence to support it. This study aimed to assess outcomes of renal vein stenting in the treatment of NCS. METHODS: A retrospective chart review of patients with NCS who underwent LRV stenting between 2010 and 2018 was performed. End points were perioperative adverse outcomes, symptom relief, and stent patency. Symptom resolution was classified as complete, partial, and none on the basis of the interpretation of medical records on clinical follow-up. Standard descriptive statistics and survival analysis were used. RESULTS: Eighteen patients (17 female; mean age, 38.1 ± 16.9 years) diagnosed with NCS and treated with LRV stenting were identified. Five of these had a prior LRV transposition that had failed within a mean of 7.0 ± 4.9 months, manifested by symptom recurrence (or no improvement) along with imaging evidence of persistently severe renal vein stenosis. Twelve patients had coexisting pelvic congestion syndrome treated with gonadal vein embolization. The most frequent sign and symptom were hematuria (10/18 patients) and flank pain (15/18 patients), respectively. All patients received self-expanding stents (mean diameter, 12.8 ± 1.6 mm), the smaller ones typically placed in the previously transposed LRVs. No perioperative complications occurred. Nine patients were discharged on the same day; the remaining patients stayed longer for pain control (mean hospital stay, 1.0 ± 1.3 days). At an average follow-up of 41.4 ± 26.6 months, 13 (72.2%) patients had symptoms resolved or improved (9 complete, 4 partial). Three of the five patients whose symptoms remained unchanged had previous LRV transposition surgery, and two of these three patients eventually required renal autotransplantation. Six of 10 patients who presented with hematuria had it resolved. Three patients underwent a stent reintervention at 5.8 months, 16.8 months, and 51.7 months because of symptom recurrence or stent restenosis. The two early ones required balloon venoplasty and the third one restenting. Two-year primary and primary assisted patency was 85.2% and 100%, respectively. No stent migration occurred. CONCLUSIONS: Endovascular treatment with renal vein stenting is safe, providing encouraging results with good midterm patency rates and symptom relief. Minimally invasive approaches may have a potential role in the treatment of NCS. Larger series and longer follow-up are needed to better assess the comparative performance against LRV transposition.

Risk factors for perioperative mortality after revascularization for acute aortic occlusion.

OBJECTIVE: Acute aortic occlusion (AAO) is a life-threatening event necessitating prompt revascularization to the pelvis and lower extremities. Because of its uncommon nature, outcomes after revascularization for AAO are not well characterized. Our aim was to describe the perioperative morbidity and mortality associated with revascularization and to identify the patients at highest risk. METHODS: A retrospective chart review was performed of patients who presented to our institution from 2006 to 2017 with acute distal aortic occlusion. Patients with a prior aortofemoral bypass were excluded, but those with aortoiliac stents were included. Baseline demographics and comorbidities, preoperative clinical presentation and imaging, procedural details, and postoperative hospital course were reviewed. The primary outcome was 30-day mortality, and major complications were evaluated as secondary outcomes. Logistic regression models were constructed to identify factors associated with 30-day mortality. RESULTS: We identified 65 patients who underwent revascularization for AAO. Median age was 63 years (range, 35-89 years), and 64.6% were male; 56.4% of patients presented within 24 hours of symptom onset, and 43.8% were treated within 6 hours of presentation. There were particularly high rates of prior coronary artery disease (62.3%) and chronic obstructive pulmonary disease (41.0%); 18.5% had prior iliac stents. Preoperative imaging in 44 patients showed occlusion of the inferior mesenteric artery in 36.0% and both internal iliac arteries in 34.7%. Treatments for revascularization included axillobifemoral bypass (55.4%), aortoiliac thromboembolectomy (15.4%), aortobifemoral bypass (13.9%), and aortoiliac stenting (15.4%). Overall 30-day mortality was 27.7% and was not affected by treatment modality. Mortality was highest in patients older than 60 years (40.5% vs 10.7%; P = .01) and those presenting with lactate elevation (45.5% vs 5.9%; P = .004) or motor deficit in at least one extremity (36.6% vs 9.5%; P = .03). Univariate predictors of 30-day mortality were age ≥60 years (odds ratio [OR], 5.68; 95% confidence interval [CI], 1.45-22.26; P = .01), presentation with motor deficit (OR, 5.48; 95% CI, 1.12-26.86; P = .04), presentation with elevated lactate level (OR, 13.33; 95% CI, 1.58-11.57; P = .02), history of prior stroke (OR, 4.80; 95% CI, 1.21-18.97; P = .03), and bilateral internal iliac artery occlusion (OR, 7.11; 95% CI, 1.54-32.91; P = .01). At least one postoperative complication was observed in 78.5% of patients, including acute kidney injury (56.9%, with 21.5% requiring hemodialysis), respiratory complications (46.2%), cardiovascular complications (33.9%), major amputation (15.4%, bilateral in 7.7%), and bowel ischemia (10.8%). CONCLUSIONS: Even with prompt revascularization and despite the chosen treatment modality, AAO carries high risk of mortality and numerous life-threatening complications. Older patients presenting with elevated lactate levels, motor deficit, and bilateral internal iliac artery occlusions are at the highest risk of perioperative mortality. These factors may aid in risk stratification and managing expectations in this critically ill population.

Nitric oxide donors for peripheral artery disease.

Current management of peripheral arterial disease involves risk factor modification and revascularisation, but many patients are still left with debilitating symptoms. Therefore, new treatment strategies are needed. The importance of nitric oxide, and its role in regulating endothelial function, is well-established. Altering the nitric oxide pathway has been extensively studied as a means of treating vascular disease, including peripheral arterial disease. Statins and ACE inhibitors have been shown to enhance endogenous nitric oxide and improve intermittent claudication symptoms. Studies using l-arginine have produced differing results, for reasons for yet fully understood. A greater understanding of the nitric oxide pathway, and its enzymatic control, has generated more potential therapeutic targets to alter NO levels.

Vascular Shunts in Civilian Trauma.

Experience with temporary intravascular shunts (TIVS) for vessel injury comes from the military sector and while the indications might be clear in geographically isolated and under resourced war zones, this may be an uncommon scenario in civilian trauma. Data supporting TIVS use in civilian trauma have been extrapolated from the military literature where it demonstrated improved life and limb salvage. Few non-comparative studies from the civilian literature have also revealed similar favorable outcomes. Still, TIVS placement in civilian vascular injuries is uncommon and by some debatable given the absence of clear indications for placement, the potential for TIVS-related complications, the widespread resources for immediate and definitive vascular repair, and the need for curtailing costs and optimizing resources. This article reviews the current evidence and the role of TIVS in contemporary civilian trauma management.