Background: This study compared outcomes of patients with acute limb ischemia (ALI) before, during, and after the COVID-19 pandemic, hypothesizing that poor outcomes observed during the pandemic have not yet been resolved. Methods: This retrospective, observational, single-center study analyzed ALI patients from 2019 to 2023. Results: Over 5 years, 298 patients underwent surgery for ALI at our hospital: 35 had COVID-19 (COVID group), 132 tested negative (non-COVID group), 71 were treated before the pandemic (pre-COVID group), and 60 after (post-COVID group). In 2020, 32% of ALI patients had COVID-19, a percentage that decreased over time. Baseline characteristics shifted, influencing treatment. The pre-COVID group had more cardiac disease with embolic ALI and required mainly embolectomy; the COVID group had worse clinical conditions, undergoing embolectomy or amputation. The post-COVID group had more thrombotic ALI, with increased bypass surgery needs. Prolonged ischemia time was a concern during the entire study; 29% of patients presented with Rutherford III ischemia at admission, and 35.2% required major amputations. COVID group had higher mortality (48.6% vs. 15.5% pre-COVID, 22.7% non-COVID, and 28.3% post-COVID, P - 0.003). Additional factors contributing to mortality included older age (OR 1.05 CI: 1.02-1.08, P < 0.001), prior stroke (OR 2.38, CI: 1.07-5.38, P < 0.001), chronic obstructive pulmonary disease (COPD) (OR 1.88, CI: 0.53-6.59, P - 0.03), and aorto-iliac ALI (OR 8.72, CI: 1.25-22.63,P<0.01). Conclusion: Delayed presentations of ALI patients persisted before, during, and after the pandemic, resulting in many cases of irreversible ischemia at admission and increased amputation rates. Mortality rates correlated with COVID-19, older age, COPD, prior stroke, and aorto-iliac involvement.

BACKGROUND:Pathologic compression of the median nerve at the elbow by the bicipital aponeurosis, or lacertus fibrosus, in athletes has been described well; however arterial compression at this level has been rarely described. We describe the evaluation and surgical treatment of a case of distal brachial artery and proximal radial artery compression by the lacertus fibrosus in a professional baseball pitcher. METHODS:We received verbal consent from the patient involved to prepare a published report of this case. RESULTS:A professional baseball pitcher presented with an acute brachial artery thrombus. The patient had been treated at multiple institutions for recurrent right upper extremity arterial occlusions and had undergone a right first rib resection for arterial thoracic outlet syndrome. The patient underwent thrombectomy of the brachial thrombus. Subsequent outpatient imaging included an unremarkable computed tomagraphy angiogram with provocative thoracic outlet syndrome maneuvers, an inconclusive dynamic magnetic resonance imaging scan, and a right upper extremity arterial duplex with an increase in radial artery velocities with the arm abducted to 90°. Right brachial and radial artery exploration and decompression was performed. Preprocedure angiography demonstrated disruption of flow distal to the brachial bifurcation with the shoulder abducted and externally rotated with elbow flexed in the "pitching" or cocking position. Following lacertus fibrosus decompression, repeat angiography demonstrated normal brachial artery blood flow in all arm positions. CONCLUSION:The patient did well postoperatively without additional episodes of arterial occlusion after nearly 3 years of follow-up.

Background: The effective management of pulmonary embolism (PE) necessitates coordinated care among physicians from diverse specialties within a time-sensitive framework. Pulmonary Embolism Response Teams (PERTs) have been developed as a strategic approach to optimize and expedite treatment by integrating and coordinating different specialties. The current survey audit aimed to understand the level of interest among vascular surgeons and the logistical considerations surrounding their participation within the PERT. Methods: A deidentified Research Electronic Data Capture (REDCap) survey was disseminated to vascular surgeons, with collected data submitted to the Vascular Surgery Collaborative Results: A total of 139 vascular surgeons with an average of 10.6 years of practice experience responded to the VASC PERT audit. The majority (70.5%) practice in academic settings and only 24.5% currently perform PE interventions in their practice. While nearly half of respondents (52.5%) reported the existence of PERT in their institutions, only a fraction (23.3%) was actively involved in the PERT. Notably, a significant proportion in our cohort (38.1%) expressed dissatisfaction with the representation of vascular surgeons in multidisciplinary teams managing venous thromboembolism (VTE), including deep vein thrombosis (DVT) and PE. Vascular surgery (VS) representation in PERT was only 34.2%, with pulmonology (pulm) (60.3%), interventional radiology (IR) (57.5%), interventional cardiology (IC) (57.5%), and critical care (CC) (50.7%) being the most represented specialties. The primary barriers to VS participation in PERT were competing interests from other specialties and logistical scheduling challenges. Conclusions: The audit shows a global deficit in the integration of VS expertize within PERT frameworks. Primary barriers include exclusion due to competing interests from other specialties and challenges in the logistical coordination of PERT calls.

Objective The COVID-19 pandemic has drastically altered the medical landscape. Various strategies have been employed to preserve hospital beds, personal protective equipment, and other resources to accommodate the surges of COVID-19 positive patients, hospital overcapacities, and staffing shortages. This has had a dramatic effect on vascular surgical practice. The objective of this study is to analyze the impact of the COVID-19 pandemic on surgical delays and adverse outcomes for patients with chronic venous disease scheduled to undergo elective operations. Methods The Vascular Surgery COVID-19 Collaborative (VASCC) was founded in March 2020 to evaluate the outcomes of patients with vascular disease whose operations were delayed. Modules were developed by vascular surgeon working groups and tested before implementation. A data analysis of outcomes of patients with chronic venous disease whose surgeries were postponed during the COVID-19 pandemic from March 2020 through February 2021 was performed for this study. Results A total of 150 patients from 12 institutions in the United States were included in the study. Indications for venous intervention were: 85.3% varicose veins, 10.7% varicose veins with venous ulceration, and 4.0% lipodermatosclerosis. One hundred two surgeries had successfully been completed at the time of data entry. The average length of the delay was 91 days, with a median of 78 days. Delays for venous ulceration procedures ranged from 38 to 208 days. No patients required an emergent intervention due to their venous disease, and no patients experienced major adverse events following their delayed surgeries. Conclusions Interventions may be safely delayed for patients with venous disease requiring elective surgical intervention during the COVID-19 pandemic. This finding supports the American College of Surgeons’ recommendations for the management of elective vascular surgical procedures. Office-based labs may be safe locations for continued treatment when resources are limited. Although the interventions can be safely postponed, the negative impact on quality of life warrants further investigation.

BackgroundResuscitative endovascular balloon occlusion of the aorta (REBOA) has been often used in place of open aortic occlusion for management of hemorrhagic shock in trauma. There is a paucity of data evaluating REBOA usage in military settings.Study Design and MethodsWe queried the Department of Defense Trauma Registry (DODTR) for all cases with at least one intervention or assessment available within the first 72 h after injury between 2007 and 2023. We used relevant procedural codes to identify the use of REBOA within the DODTR, and we used descriptive statistics to characterize its use.ResultsWe identified 17 cases of REBOA placed in combat settings from 2017 to 2019. The majority of these were placed in the operating room (76%) and in civilian patients (70%). A penetrating mechanism caused the injury in 94% of cases with predominantly the abdomen and extremities having serious injuries. All patients subsequently underwent an exploratory laparotomy after REBOA placement, with moderate numbers of patients having spleen, liver, and small bowel injuries. The majority (82%) of included patients survived to hospital discharge.DiscussionWe describe 17 cases of REBOA within the DODTR from 2007 to 2023, adding to the limited documentation of patients undergoing REBOA in military settings. We identified patterns of injury in line with previous studies of patients undergoing REBOA in military settings. In this small sample of military casualties, we observed a high survival rate.

With the widespread postponement of scheduled vascular operations during the pandemic, the Vascular Surgery COVID-19 Collaborative evaluated the outcomes of the delays. Retrospective analysis of prospectively collected data from the Vascular Surgery COVID-19 Collaborative REDcap database. Observed risk of complications was compared to expected risk (OE) using the Surgical Risk Preoperative Assessment System (SURPAS). SURPAS is a parsimonious model which was developed and previously validated using the American College of Surgeons National Surgical Quality Improvement Program Participant Use File. We used eight predictor variables across five conditions and 35 vascular procedures to calculate SURPAS estimates. A total of 1002 vascular operations were rescheduled in the United States during the coronavirus disease 2019 pandemic with a median surgery delay of 64 days (interquartile range, 38-106 days). The mean age of patients was 62.28 ± 14.81 years, 55% (n = 543) males, and 56.8% (n = 528) White. Almost one-half of the cohort (49.1%) were American Society of Anesthesiologists class IV, with comorbidities including 72.2% hypertension, 40.7% smokers, 36.5% diabetes mellitus, 35.8% renal disease, 27.4% coronary artery disease, and 21.6% obesity. While waiting for their surgeries, 1.5% (n = 15) needed emergency surgery, 12.4% (n = 124) were canceled, and 2.9% (n = 29) died. The events rate of each complication by the condition shows a significantly lower observed complications ratio with endovascular abdominal aortic aneurysm (OE, 0.310; 95% confidence interval [CI], 0.029-0.887), carotid endarterectomy (OE, 0.298; 95% CI, 0.028-0.855), and open bypass for peripheral arterial disease (PAD) (OE, 0.395; 95% CI, 0.074-0.968). The highest pre and postoperative mortality rates were in the aortic group (6.4%; n = 11). (Table I) The overall OE risk ratio for each complication shows significantly higher than expected pre and postoperative mortality ratio in the rescheduled hemodialysis operations (OE, 3.31; 95% CI, 1.7-5.45); significantly lower overall morbidity in the carotid (OE, 0.24; 95% CI, 002-0.68); significantly lower infection in the PAD (OE, 0.19; 95% CI, 0.02-0.55); significantly lower venous thromboembolism in the aortic (OE, 0.02; 95% CI, 0-0.087) and PAD (OE, 0.04; 95% CI, 10.01-0.097); and significantly lower bleeding in the PAD group (OE, 0.24; 95% CI, 0.08-0.49) (Table II). Higher OE mortality in rescheduled hemodialysis patients warrants prioritizing them during a future pandemic. The OE mortality in our cohort of patients undergoing aortic, carotid, and chronic limb-threatening ischemia as a whole was comparable to the expected rates before the pandemic. The significantly lower observed to expected complication rate with patients whose EVAR, carotid endarterectomy, and open bypass for PAD surgeries were postponed during the height of the pandemic warrants further investigation.Table IOverall complication observed to expected estimates by procedureProcedureOE (95% CI)No.Aortic EVAR (tube, bifurcated, or modular)0.310 (0.029, 0.887)31/173 FEVAR0.901 (0.357-1.692)29/173 TEVAR without left subclavian coverage0.499 (0.047-1.431)9/173Carotid Carotid endarterectomy0.298 (0.028-0.855)31/69 Arteriovenous graft creation0.766 (0.0003-3.003)16/265Hemodialysis Fistulogram1.446 (0.456-2.992)31/265 Native arteriovenous fistula creation1.335 (0.727-2.125)101/265 Open revision of access0.638 (0.0002-2.502)18/265PAD Covered stent2.109 (0.398-5.17)6/254 Endo – drug-coated balloon angioplasty2.228 (0.802-4.367)22/254 Endo - plain old balloon angioplasty1.421 (0.878-2.093)66/254 Endo - stent0.733 (0.069-2.101)20/254 Open - bypass0.395 (0.074-0.968)22/254 Open - endarterectomy1.159 (0.302-2.574)8/254Venous Phlebectomy of varicosities3.022 (0.285-8.662)21/226 Vein ablation, thermal2.651 (0.689-5.885)65/226CI, Confidence interval; EVAR, endovascular aneurysm repair; FEVAR, fenestrated endovascular aortic repair; PAD, peripheral arterial disease; TEVAR, thoracic endovascular aneurysm repair. Open table in a new tab Table IIPostoperative complication and observed to expected ratio (OE)Aortic, 173 (17.5%)Carotid, 69 (7%)Hemodialysis, 265 (26.8%)PAD, 254 (25.7%)Venous, 226 (22.9%)Outcomes Mortality pre- or postoperative11/173 (6.4%)3/69 (4.3%)12/265 (4.5%)14/261 (5.4%)0/226 (0%) Morbidity24/122 (19.7%)2/41 (4.9%)22/197 (11.2%)61/210 (29.0%)8/144 (5.6%)Overall OE Mortality pre- or postoperative1.14 (0.57-1.91)0.92 (0.17-2.25)3.31 (1.7-5.45)1.18 (0.64-1.88)0.00 Morbidity0.74 (0.48-1.07)0.24 (0.02-0.68)1.09 (0.68-1.59)1.33 (1.01-1.68)1.84 (0.79-3.34) Infection0.68 (0.13-1.66)0.000.000.19 (0.02-0.55)0.00 VTE0.02 (0.00-0.087)0.000.000.04 (0.01-0.097)0.00 Myocardial infarction0.63 (0.06-1.80)0.001.86 (0.35-4.57)1.03 (0.27-2.29)0.00 Bleeding0.60 (0.26-1.10)0.000.77 (0.15-1.90)0.24 (0.08-0.49)0.00 Renal disease0.34 (0.00-1.35)0.002.39 (0.23-6.85)0.69 (0.07-1.99)0.00 Stroke0.46 (0.00-1.8)0.000.000.73 (0.00-2.85)0.00PAD, Peripheral arterial disease; VTE, venous thromboembolism.Morbidity was defined as having any complications (infection, venous thromboembolism, myocardial infarction, bleeding, renal disease, stroke, and mortality). Values are number (%) or OE, (95% confidence interval). Open table in a new tab

Despite advances in open and endovascular management of trauma, vascular injuries remain a source of devastating outcomes. This narrative review of the literature between 2018 and 2023 explored recent advances in abdominopelvic and lower extremity vascular injury management. New conduit choices, use of temporary intravascular shunts, and advances in endovascular management of vascular trauma were reviewed. Although endovascular techniques are being applied more frequently, there is a paucity of reporting on long-term outcomes. Open surgery is durable and effective and remains the gold standard for repairing most abdominal, pelvic, and lower extremity vascular injuries. Vascular reconstruction conduit options are currently limited to the autologous vein, prosthetic grafts, and cryopreserved cadaveric xenografts; each type has its own application challenges. The temporary intravascular shunts can be used to restore early perfusion to ischemic limbs and increase the chances of limb salvage, or when transfer of care is needed. Resuscitative balloon occlusion of the inferior vena cava has been a research-heavy topic to investigate the possible implications in patients with trauma. Early diagnosis, appropriate use of technology, and time-sensitive management can make all the difference in the lives of patients with vascular trauma. Endovascular management of vascular trauma is evolving and gaining wider acceptance for treatment of vascular injuries. Computed tomography angiography is widely available and is the current gold standard for diagnosis. Autologous vein remains the gold standard for conduit with the future promise of new innovative conduits. Vascular surgeons have an important role in vascular trauma management.

Background: To measure the impact of the COVID-19 pandemic on the management of pa-tients with carotid artery stenosis.Methods: We prospectively collected data from 25 centers (19 centers in the United States and 6 centers internationally) on postponed carotid artery operations between March 2020 and January 2022. We describe the characteristics of these patients and their planned operations, along with outcomes including mortality and neurological deterioration during the period of oper-ative delay due to the COVID-19 pandemic.Results: A total of 1,220 vascular operations were postponed during the pandemic, of them 96 patients presented with significant carotid stenosis (median stenosis of 71%; interquartile range; 70e80) and 80% of them were planned for carotid endarterectomy. Most patients were asymp-tomatic (69%), and 31% of patients were symptomatic (16% of patients had a stroke, 15% of patients had a transient ischemic attack, and 1% of patients experienced amaurosis fugax). The median length of surgical delay was 71 days (interquartile range: 45.5, 115.5). At the data entry time, 62% of patients had their carotid operations postponed and successfully completed. Most postponements (72%) were due to institutional policies aimed at resource con-servation. During the delay, no patient decompensated or required an urgent operation. A total of 5 patients (5%) with carotid stenosis died while awaiting operations due to COVID-19. Conclusions: Our study of a cohort of patients with carotid artery stenosis who underwent a median delay of 71 days during the COVID-19 pandemic showed a disparate operation delay between US regions and internationally, most postponements were due to hospital policy, and none of the patients deteriorated or required an emergency surgery during the delay.

A competitive Nordic skier presented with bilateral exertional leg pain. Training regimen included strength training, aerobic and anaerobic exercise, skiing 5 days a week, and competitions on the weekends. Pain was not relieved following bilateral fasciotomies for chronic exertional compartment syndrome. Patient progressed from usual state of health and at the peak of performance to short distance claudication within the period of a few months. Duplex ultrasound examination with provocative maneuvers showed no evidence of popliteal artery entrapment. There was evidence of distal anterior tibial/proximal dorsalis pedis artery compression with plantarflexion (Fig 1). Retrograde dorsalis pedis artery and arcuate arteries were observed with plantarflexion. The ankle-brachial index (ABI) was normal at rest. There was some decrease in toe perfusion with active plantarflexion, however, with forced passive plantarflexion, no flow could be detected by the toe photoplethysmography sensors. Dorsalis pedis artery entrapment syndrome from hypertrophied extensor hallucis longus muscle belly was suspected and informed consent obtained to surgically relieve the compression. The surgery was performed with the collaboration of the orthopedic surgery team. An incision was made on the anterior aspect of the right foot overlying the tendon bundle and traversing the joint to reach the retinaculum. The retinaculum was then sharply incised, which revealed a hypertrophied extensor hallucis longus muscle belly (Fig 2). The muscle belly was resected from the tendon at this portion of the foot. Duplex ultrasound examination performed postoperatively showed normal velocities and waveforms in the dorsalis pedis artery with foot at rest, with flexion, and extension. The same operation was performed one month later on the left foot. The patient had an uneventful recovery and returned to high-level competition, doing well at 2-year follow-up.Fig 2Intraoperative image showing hypertrophied extensor hallucis longus muscle belly compressing the dorsalis pedis artery.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Median arcuate ligament syndrome (MALS) is a rare entity that presents with severe and life-limiting abdominal pain and food fear. The robotic platform has recently emerged as a tool for MALS release owing to enhanced visualization and ergonomics. The aim of this study was to evaluate the feasibility and results of robotic phrenoesophageal membrane preserving release of the median arcuate ligament (PEMP-MALS) for the treatment of celiac artery compression syndrome.

Background COVID-19 infection is associated with thrombotic events; however, this phenomenon is poorly understood. Few studies have reported the association between COVID-19 and stroke in the hospital setting. Methods We retrospectively reviewed and characterized all patients who presented to a single, quaternary medical center between March and December 2020 (N=603). COVID-19 positive patients who developed ischemic or hemorrhagic stroke were included in the analysis (N=66). This cohort was compared with patients who were COVID-19 negative at the time of stroke presentation in the same period (N=537). Statistical significance was evaluated using Pearson's Chi squared test with Yates' continuity correction and linear model ANOVA. Results Sixty-six patients had COVID-19 and Stroke. Of these patients, 22 (33.4%) patients initially presented with stroke and 44 (66.7%) initially presented with COVID-19. Patients who presented with COVID-19 and had a stroke during their hospitalization (COVID-first) had worse outcomes than patients presenting to the hospital with stroke whose COVID test became positive later in the hospitalization (stroke-first). Patients who presented with COVID-19 and had a stroke during their hospitalization had an increased rate of acute renal failure (48.9% vs 19.0%, p=0.021) and need for ventilation (60.0% vs 28.6%, p=0.017). Further, in the COVID-first cohort, the use of heparin prior to the stroke event was not associated with mortality or type of stroke (ischemic or hemorrhagic). Conclusion In the early pandemic, patients with COVID-19 infection and stroke had a higher mortality rate compared to COVID-19 negative patients with stroke. Among patients with both COVID-19 and stroke, patients presenting with COVID-19 first had worse outcomes than patients presenting with stroke first. The use of heparin prior to the stroke event was not associated with mortality or type of stroke.### Competing Interest StatementThe authors have declared no competing interest.### Funding StatementNo funding received.### Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:This retrospective observational study complies with the US Health Insurance Portability and Accountability Act (HIPPA) of 1996 and was exempted by the Colorado Multiple Institutional Review Board.Submission ID: PAM001-1.I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.YesDr. Wohlauer had full access to all the data in the study and takes responsibility for its integrity and the data analysis.

Objective: We aimed to characterize patients with COVID-19 and stroke and compare outcomes with patients with stroke only in the hospital setting. Background: COVID-19 infection is associated with a hypercoagulable state which results in thrombotic events, such as ischemic stroke. However, few studies have reported patient outcomes based on the primary presentation (COVID-19 or stroke first), and the association between COVID-19 and hemorrhagic stroke in the hospital setting. Design/Methods: We retrospectively reviewed and characterized all patients (N=66) who were COVID-19 positive at the time of ischemic or hemorrhagic presentation to a tertiary medical center between March 2020 and December 2020. This cohort was compared with patients who were COVID-19 negative at the time of stroke presentation in the same period (N=537). Statistical significance was evaluated using Pearson's Chi-squared test with Yates' continuity correction. Results: The mean age of stroke patients with COVID-19 was 62.1 years old with 62.1% identified as male and 37.9% as female, which is similar to the cohort without COVID-19 (mean age=64.7). Of the COVID-19 positive patients, multiple comorbidities were identified including hypertension (68.2%), diabetes mellitus (56.1%), and hyperlipidemia (36.4%). 22 (33.4%) patients initially presented with stroke and 44 (66.7%) initially presented with COVID-19. Overall mortality was 37.9% with 36.4% in the stroke-first cohort and 38.6% in the COVID-first cohort. This is significantly higher than patients who had a stroke only (17.3%, p<0.001). In the stroke-first cohort, 22.7% patients presented with a hemorrhagic stroke and 77.2% with an ischemic stroke. In the COVID-first cohort, 38.6% experienced a hemorrhagic stroke while 61.4% had an ischemic stroke with similar mortality rates. Conclusions: In the early pandemic, we found that patients with COVID-19 infection and stroke, regardless of the primary presentation, had a higher mortality rate than patients with only stroke. Mortality rates were similar between patients with a hemorrhagic stroke and an ischemic stroke. Disclosure: Miss Liu has nothing to disclose. Ms. Gillette has nothing to disclose. The institution of Dr. Poisson has received research support from Biogen. Ms. Jeppson has nothing to disclose. Mrs. Ravare has nothing to disclose. Dr. Wohlauer has received publishing royalties from a publication relating to health care.

The COVID-19 pandemic has profoundly affected health care delivery. In addition to the significant morbidity and mortality associated with acute illness from COVID-19, the indirect impact has been far-reaching, including substantial disruptions in chronic disease care. As a result of pandemic disruptions in health care, vulnerable and minority populations have faced health inequalities. The aim of this review was to investigate how the COVID-19 pandemic has impacted vulnerable populations with limb-threatening peripheral artery disease and diabetic foot infections.

Although the topics of surgical techniques and medical therapies have been widely studied in aortic dissection (AD), studies examining the short- and long-term impact of this event on mental health are largely lacking. Many of the studies have used the 36-Item Short Form Survey at variable time points after the event. However, AD as medical trauma has a complex impact on a person's identity. Its implications for emotional, mental, social, existential, and self-concept could be explored more robustly. This topic was identified as a topic of interest by the AD Collaborative. The AD Collaborative Mental Health Working Group was formed and performed a landscape review to summarize current literature surrounding quality of life research in those who have experienced AD, identify gaps in knowledge, and to outline future research questions.

Background: Patients with peripheral artery disease (PAD) requiring lower extremity revascularization (LER) have a high risk of adverse limb and cardiovascular events. The results from the VOYAGER PAD (efficacy and safety of rivaroxaban in reducing the risk of major thrombotic vascular events in subjects with symptomatic peripheral artery disease undergoing peripheral revascularization procedures of the lower extremities) trial have demonstrated that rivaroxaban significantly reduced this risk with an overall favorable net benefit for patients undergoing surgical revascularization. However, the efficacy and safety for those treated by surgical bypass, including stratification by bypass conduit (venous or prosthetic), has not yet been described. Methods: In the VOYAGER PAD trial, patients who had undergone surgical and endovascular infrainguinal LER to treat PAD were randomized to rivaroxaban 2.5 mg twice daily or placebo on top of background antiplatelet therapy (aspirin 100 mg to be used in all and clopidogrel in some at the treating physician's discretion) and followed up for a median of 28 months. The primary end point was a composite of acute limb ischemia, major amputation of vascular etiology, myocardial infarction, ischemic stroke, and cardiovascular death. The principal safety outcome was major bleeding using the TIMI (thrombolysis in myocardial infarction) scale. The index procedure details, including conduit type (venous vs prosthetic), were collected at baseline. Results: Among 6564 randomized patients, 2185 (33%) had undergone surgical LER. Of these 2185 patients, surgical bypass had been performed for 1448 (66%), using a prosthetic conduit for 773 patients (53%) and venous conduit for 646 patients (45%). Adjusting for the baseline differences and anatomic factors, the risk of unplanned limb revascularization in the placebo arm was 2.5-fold higher for those receiving a prosthetic conduit vs a venous conduit (adjusted hazard ratio [HR], 2.53; 95% confidence interval [CI], 1.65-3.90; P < .001), and the risk of acute limb ischemia was three times greater (adjusted HR, 3.07; 95% CI, 1.84-5.11; P < .001). The use of rivaroxaban reduced the primary outcome for the patients treated with bypass surgery (HR, 0.78; 95% CI, 0.62-0.98), with consistent benefits for those receiving venous (HR, 0.66; 95% CI, 0.49-0.96) and prosthetic (HR, 0.87; 95% CI, 0.66-1.15) conduits (P-interaction = .254). In the overall trial, major bleeding using the TIMI scale was increased with rivaroxaban. However, the numbers for those treated with bypass surgery were low (five with rivaroxaban vs nine with placebo; HR, 0.55; 95% CI, 0.18-1.65) and not powered to show statistical significance. Conclusions: Surgical bypass with a prosthetic conduit was associated with significantly higher rates of major adverse limb events relative to venous conduits even after adjustment for patient and anatomic characteristics. Adding rivaroxaban 2.5 mg twice daily to aspirin or dual antiplatelet therapy significantly reduced this risk, with an increase in the bleeding risk, but had a favorable benefit risk for patients treated with bypass surgery, regardless of conduit type. Rivaroxaban should be considered after lower extremity bypass for symptomatic PAD to reduce ischemic complications of the heart, limb, and brain.

Vascular research questions can be answered using various study designs. Observational studies are used frequently to address a wide range of clinical questions when randomized clinical trials are not feasible or practical. One of the powerful vascular research tools is the cohort study. The cohort study is a reliable observational study design in which individuals who share a common characteristic (a cohort) are followed over time and their outcomes are assessed at various intervals. This review focuses on the essential characteristics, design, implementation, bias, validity, and clinical significance of cohort studies and provides illustrative examples. A cohort study can be either a prospective or a retrospective study, depending on whether the outcome occurred before or after the enrollment of the cohort. Each type has its advantages and disadvantages. Confounding, selection, and information biases can all occur in cohort studies. Applications of the cohort study design include studying the natural history of a disease, describing a condition's frequency, and investigating multiple outcomes simultaneously.

Acute limb ischemia (ALI) is one of the most catastrophic thrombotic manifestations of COVID-19 resulting in limb loss if not promptly treated. Our goal is to evaluate revascularization outcomes of ALI in patients with COVID-19 who underwent either open or endovascular treatment. The Vascular Surgery COVID-19 Collaborative started in March 2020 to assess hematological changes of COVID-19. We performed an interim data analysis on 46 patients with COVID-19 associated ALI submitted to the ALI module of the Vascular Surgery COVID-19 Collaborative REDcap database from 10 institutions in the United States. Among the 46 patients included in the analysis, the mean age was 62.2 (standard deviation [SD]: 9.51) years. The majority of patients were male (73.9%). A total of 67.4% were White, 13% were Hispanic, and 4.3% were Black. In total, 93.5% of patients met Rutherford’s criteria of ALI class 2 or 3. On average, patients developed ALI 12.2 (SD: 13.5) days after a positive COVID test. Revascularization was attempted using open thrombectomy in 50.0%, endovascular lysis or thrombectomy in 23.9%, and bypass in 2.2%, and revascularization was not attempted in 23.9% of the patients (Table). Revascularization was successful in 41.3% with symptom resolution and 15.2% with limb salvage but persistent symptoms; 2.2% had minor amputation, 4.3% ultimately had a major amputation, 4.3% required reoperation, and revascularization was unsuccessful in 10.9% of patients. The average length of hospital stay was 13.2 (SD: 13.3) days, the average intensive care unit (ICU) length of stay was 4.66 (SD: 6.85) days, and the average ventilation days was 12.3 (SD: 10.8) days. Overall, in-hospital mortality was 21.7%, 8.7% had major amputation, 8.7% had stroke, 6.5% required major limb intervention, and 2.2% had sepsis. Successful revascularization rate was 62.5% in the 24 patients who underwent open surgery vs 36.4% in the 11 patients who underwent endovascular repair. The average length of stay in the ICU was shorter in the open group (mean = 3.24 days) than in the endovascular group (mean = 8.60 days). Of the 11 patients who had no revascularization attempt, 36.4% died, 18.2% had a major amputation, 9.1% had a pulmonary embolism, and 9.1% had a stroke. COVID-19-associated ALI carries a high mortality. Patients with COVID-19 who develop ALI can be managed successfully with open surgery or endovascular intervention. In our cohort, open revascularization resulted in reduced ICU stay and reduced ventilation days with improved limb salvage than the endovascular group. Further data are needed to develop management algorithms for ALI in patients with COVID-19.TableRevascularization outcomesEndovascular (N = 11)Open (N = 24)None (N = 11)Overall (N = 46)Age, mean (SD)65.1 (6.17)60.8 (8.59)62.2 (13.6)62.2 (9.51)Diabetes mellitus4 (36.4)9 (37.5)5 (45.5)18 (39.1)Rutherford ALI scale I0 (0)0 (0)3 (27.3)3 (6.5) IIa4 (36.4)9 (37.5)2 (18.2)15 (32.6) IIb5 (45.5)14 (58.3)2 (18.2)21 (45.7) III2 (18.2)1 (4.2)4 (36.4)7 (15.2)No preoperative anticoagulation medication use6 (54.5)22 (91.7)22 (91.7)37 (80.4)No preoperative antiplatelet medication use3 (27.3)13 (54.2)7 (63.6)23 (50.0)Preoperative aspirin use18 (39.1)9 (37.5)4 (36.4)18 (39.1)Successful revascularization with symptom resolution4 (36.4)15 (62.5)0 (0)19 (41.3)Major amputation1 (9.1)1 (4.2)1 (9.1)4 (8.7)Ventilation in days, mean (SD)17.7 (9.61)10.6 (13.0)8.50 (7.78)12.3 (10.8)Average length of stay in ICU, days, mean (SD)8.60 (9.86)3.24 (4.96)3.29 (5.19)4.66 (6.85)Average length of stay in hospital, days, mean (SD)11.9 (10.5)12.8 (14.3)11.9 (10.5)13.2 (13.3)Death, in hospital3 (27.3)3 (6.5)4 (36.4)10 (21.7)Death, within 30 days1 (9.1)1 (4.2)0 (0)3 (6.5)ICU, Intensive care unit; SD, standard deviation.Data are presented as number (%) unless otherwise indicated. Open table in a new tab