The natural history and long-term follow-up of splenic artery aneurysms.

OBJECTIVE: Although splenic artery aneurysms (SAAs) are the most common visceral aneurysm, there is a paucity of literature on the behavior of these entities. The objective of this study was to review the natural history of patients with SAA. METHODS: This single-institution, retrospective analysis studied patients with SAA diagnosed by computed tomography imaging between 2015 and 2019, identified by our institutional radiology database. Imaging, demographic, and clinical data were obtained via the electronic medical record. The growth rate was calculated for patients with radiologic follow-up. RESULTS: The cohort consisted of 853 patients with 890 SAAs, of whom 692 were female (81.2%). There were 37 women (5.3%) of childbearing age (15-50 years). The mean age at diagnosis was 70.9 years (range: 28-100 years). Frequently observed medical comorbidities included hypertension (70.2%), hypercholesterolemia (54.7%), and prior smoking (32.2%). Imaging indications included abdominal pain (37.3%), unrelated follow-up (28.0%), and follow-up of a previously noted visceral artery aneurysm (8.6%). The mean diameter at diagnosis was 13.3 ± 6.3 mm. Anatomic locations included the splenic hilum (36.0%), distal splenic artery (30.3%), midsplenic artery (23.9%), and proximal splenic artery (9.7%). Radiographically, the majority were saccular aneurysms (72.4%) with calcifications (88.5%). One patient (38-year-old woman) was initially diagnosed at the time of rupture of a 25 mm aneurysm; this patient underwent immediate endovascular intervention with no complications. The mean clinical follow-up among 812 patients was 4.1 ± 4.0 years, and the mean radiological follow-up among 514 patients was 3.8 ± 6.8 years. Of the latter, 122 patients (23.7%) experienced growth. Aneurysm growth rates for initial sizes <10 mm (n = 123), 10 to 19 mm (n = 353), 20 to 29 mm (n = 34), and >30 mm (n = 4) were 0.166 mm/y, 0.172 mm/y, 0.383 mm/y, and 0.246 mm/y, respectively. Of the entire cohort, 27 patients (3.2%) eventually underwent intervention (81.5% endovascular), with the most common indications including size/growth criteria (70.4%) and symptom development (18.5%). On multivariate analysis, only prior tobacco use was significantly associated with aneurysm growth (P = .028). CONCLUSIONS: The majority of SAAs in this cohort remained stable in size, with few patients requiring intervention over a mean follow-up of 4 years. Current guidelines recommending treatment of asymptomatic aneurysms >30 mm appear appropriate given their slow progression. Despite societal recommendations for intervention for all SAAs among women of childbearing age, only a minority underwent vascular surgical consultation and intervention in this series, indicating that these recommendations are likely not well known in the general medical community.

Natural history of internal carotid artery stenosis progression.

OBJECTIVE: The aim of this study was to investigate the natural history of internal carotid artery (ICA) stenosis progression. METHODS: This single-institution retrospective cohort study analyzed patients diagnosed with ICA stenosis of 50% or greater on duplex ultrasound from 2015 to 2022. Subjects were drawn from our institutional Intersocietal Accreditation Commission-accredited noninterventional vascular laboratory database. Primary outcomes were incidences of disease progression, and stroke or revascularization after index study. Progression was defined as an increase in stenosis classification category. Imaging, demographic, and clinical data was obtained from our institutional electronic medical record via a database mining query. Cases were analyzed at the patient and artery levels, with severity corresponding to the greatest degree of ICA stenosis on index and follow-up studies. RESULTS: Of 577 arteries in 467 patients, mean cohort age was 73.5 ± 8.9 years at the time of the index study, and 45.0% (n = 210) were female. Patients were followed with duplex ultrasound for a mean of 42.2 ± 22.7 months. Of 577 arteries, 65.5% (n = 378) at the index imaging study had moderate (50%-69%) stenosis, 23.7% (n = 137) had severe (70%-99%) stenosis, and 10.7% (n = 62) were occluded. These three groups had significant differences in age, hypertension, hyperlipidemia prevalence, and proportion on best medical therapy. Of the 467-patient cohort, 56.5% (n = 264) were on best medical therapy, defined as smoking cessation, treatment with an antiplatelet agent, statin, and antihypertensive and glycemic agents as indicated. Mean time to progression for affected arteries was 28.0 ± 20.5 months. Of those arteries with nonocclusive disease at diagnosis, 21.3% (n = 123) progressed in their level of stenosis. Older age, diabetes, and a history of vasculitis were associated with stenosis progression, whereas antiplatelet agent use trended towards decreased progression rates. Of the 467 patients, 5.6% (n = 26) developed symptoms; of those, 38.5% (n = 10) had ischemic strokes, 26.9% (n = 7) had hemispheric transient ischemic attacks, 11.5% (n = 3) had amaurosis fugax, and 23.1% (n = 6) had other symptoms. A history of head and neck cancer was positively associated with symptom development. Of 577 affected arteries, 16.6% (n = 96) underwent intervention; 81% (n = 78) of interventions were for asymptomatic disease and 19% (n = 18) were for symptomatic disease. No patient-level factors were associated with risk of intervention. CONCLUSIONS: A significant number of carotid stenosis patients experience progression of disease. Physicians should consider long-term surveillance on all patients with carotid disease, with increased attention paid to those with risk factors for progression, particularly those with diabetes and a history of vasculitis.

Duplex ultrasound and cross-sectional imaging in carotid artery occlusion diagnosis.

OBJECTIVE: Investigations into imaging modalities in the diagnosis of extracranial carotid artery occlusion (CAO) have raised questions about the inter-modality comparability of duplex ultrasound (DUS) and cross-sectional imaging (CSI). This study examines the relationship between DUS and CSI diagnoses of extracranial CAO. METHODS: This single-institution retrospective analysis studied patients with CAO diagnosed by DUS from 2010 to 2021. Patients were identified in our office-based accredited vascular laboratory database. Imaging and clinical data was obtained via our institutional electronic medical record. Primary outcome was discrepancy between DUS and CSI modalities. Secondary outcomes included incidence of stroke and intervention subsequent to CAO diagnosis. RESULTS: Of our 140-patient cohort, 95 patients (67.9%) had DUS follow-up (mean, 42.7 ± 31.3 months). At index duplex, 68.0% of individuals (n = 51) were asymptomatic. Seventy-five patients (53.6%) had CSI of the carotids after DUS CAO diagnosis; 18 (24%) underwent magnetic resonance imaging and 57 (76%) underwent computed tomography. Indications for CSI included follow-up of DUS findings of carotid stenosis/occlusion (44%), stroke/transient ischemic attack (16%), other symptoms (12%), preoperative evaluation (2.7%), unrelated pathology follow-up (9.3%), and outside institution imaging with unavailable indications (16%). When comparing patients with CSI and those without, there were no differences with regard to symptoms at diagnosis, prior neck interventions, or hypertension. There was a significant difference between cross-sectionally imaged and non-imaged patients in anti-hypertensive medications (72% vs 53.8%; P = .04). Despite initial DUS diagnoses of carotid occlusion, 10 patients (13.3%) ultimately had CSI indicating patent carotids. Four of these 10 patients had stenoses of ∼99% (with 1 string sign), four of 70% to 99%, one of 50% to 69%, and one of less than 50% on CSI. The majority of patients (70%) had CSI within 1 month of the index ultrasound. There were no significant relationships between imaging discrepancies and body mass index, heart failure, upper body edema, carotid artery calcification, and neck hardware. Eight individuals (10.7%) underwent ipsilateral revascularization; 62.5% (n = 5) were carotid endarterectomy procedures, and the remaining three procedures were a transcervical carotid revascularization, subclavian to internal carotid artery bypass, and transfemoral carotid artery stenting. Eight patients (10.7%) underwent contralateral revascularization, with the same distribution of procedures as those ipsilateral to occlusions. Two of the 10 patients with discrepancies underwent carotid endarterectomy, and one underwent carotid stenting. CONCLUSIONS: In our experience, duplex diagnosis of CAO is associated with a greater than 10% discordance when compared with CSI. These patients may benefit from closer surveillance as well as confirmatory computed tomography or magnetic resonance angiography. Further work is needed to determine the optimal diagnostic modality for CAO.

Prior authorization requirements in the office-based laboratory setting are administratively inefficient and threaten timeliness of care.

OBJECTIVE: The objective of this study was to investigate the administrative and clinical impacts of prior authorization (PA) processes in the office-based laboratory (OBL) setting. METHODS: This single-institution, retrospective analysis studied all OBL PAs pursued between January 2018 and March 2022. Case, PA, and coding information was obtained from the practice's scheduling database. RESULTS: Over the study period, 1854 OBL cases were scheduled; 8% (n = 146) required PA. Of these, 75% (n = 110) were for lower extremity arterial interventions, 19% (n = 27) were for deep venous interventions, and 6% (n = 9) were for other interventions. Of 146 PAs, 19% (n = 27) were initially denied but 74.1% (n = 7) of these were overturned on appeal. Deep venous procedures were initially denied, at 43.8% (n = 14), more often than were arterial procedures, at 11.8% (n = 13). Of 146 requested procedures, 4% (n = 6) were delayed due to pending PA determination by a mean 14.2 ± 18.3 working days. An additional 6% (n = 8) of procedures were performed in the interest of time before final determination. Of the seven terminally denied procedures, 57% (n = 4) were performed at cost to the practice based on clinical judgment. CONCLUSIONS: Using PA appeals mechanisms, while administratively onerous, resulted in the overturning of most initial denials.

Natural history of renal artery aneurysms.

OBJECTIVE: The existing renal artery aneurysm (RAA) literature is largely composed of reports of patients who underwent intervention. The objective of this study was to review the natural history of RAA. METHODS: This single-institution retrospective analysis studied all patients with RAA diagnosed by computed tomography imaging between 2015 and 2019, identified by our institutional radiology database. Imaging, demographic, and clinical data were obtained via the electronic medical record. He growth rate was calculated for all patients with radiological follow-up. RESULTS: The cohort consists of 331 patients with 338 RAAs. Most patients were female (61.3%), with 11 (3.3%) of childbearing age. The mean age at diagnosis was 71.5 years (range, 24-99 years). Medical comorbidities included hypertension (73.7%), prior smoking (34.4%), and connective tissue disease (3.9%). Imaging indications included abdominal pain (33.5%), unrelated follow-up (29.6%), and follow-up of an RAA initially diagnosed before the study period (10.7%). Right RAA (61.9%) was more common than left (35.1%); 3% of patients had bilateral RAA. The mean diameter at diagnosis was 12.9 ± 5.9 mm. Size distribution included lesions measuring less than <15 mm (69.9%), 15 to 25 mm (27.1%), and more than 25 mm (3.0%). Anatomic locations included the distal RA (26.7%), renal hilum (42.4%), and mid-RA (13.1%). The majority were true aneurysms (98%); of these, 72.3% were fusiform and 27.7% were saccular. Additional characteristics included calcification (82.2%), thrombus (15.9%), and dissection (0.9%). Associated findings included aortic atherosclerosis (65.6%), additional visceral aneurysms (7.3%), and abdominal aortic aneurysm (5.7%). The mean clinical follow-up among 281 patients was 41.0 ± 24.0 months. The mean radiological follow-up among 137 patients was 26.0 ± 21.4 months. Of these, 43 patients (31.4%) experienced growth, with mean growth rate of 0.23 ± 4.7 mm/year; the remainder remained stable in size. Eight patients eventually underwent intervention (5 endovascular), with the most common indications including size criteria (4/8) and symptom development (3/8). No patient developed rupture. On multivariate analysis, obesity (P = .04) was significantly associated with growth. An initial diameter of more than 25 mm was significantly associated with subsequent intervention (P = .006), but was not significantly associated with growth. Four of five RAAs with an initial diameter 30 mm or greater did not undergo intervention. The mean clinical follow-up for these patients was 24 months; none developed rupture and two remained stable in size. CONCLUSIONS: This large institutional cohort found that the majority of RAAs remained stable in size, with few patients meeting indications for repair based on societal guidelines. Current guidelines recommending intervention for asymptomatic aneurysms more than 30 mm seem to be appropriate given their slow progression.

The Natural History of Carotid Artery Occlusions Diagnosed on Duplex Ultrasound.

BACKGROUND: There is a paucity of literature on the natural history of extracranial carotid artery occlusion (CAO). This study reviews the natural history of this patient cohort. METHODS: This single-institution retrospective analysis studied patients with CAO diagnosed by duplex ultrasound between 2010 and 2021. Patients were identified by searching our office-based Intersocietal Accreditation Commission accredited vascular laboratory database. Imaging and clinical data were obtained via our institutional electronic medical record. Outcomes of interest included ipsilateral stroke, attributable neurologic symptoms, and ipsilateral intervention after diagnosis. RESULTS: The full duplex database consisted of 5,523 patients who underwent carotid artery duplex examination during the study period. The CAO cohort consisted of 139 patients; incidence of CAO was 2.5%. Mean age at diagnosis was 69.7 years; 31.4% were female. Hypertension (72.7%), hyperlipidemia (64.7%), and prior smoking (43.9%) were the most common comorbid conditions. Of the CAO cohort, 61.3% (n = 85) of patients were asymptomatic at diagnosis; 38.8% (n = 54) were diagnosed after a stroke or transient ischemic attack occurring within 6 months prior to diagnosis, with 21.6% occurring ipsilateral to the CAO and 10.1% occurring contralateral to the CAO. 7.2% (n = 10) had unclear symptoms or laterality at presentation. Of the CAO cohort, 95 patients (68.3%) had duplex imaging follow-up (mean 42.7 ± 31.3 months). Of those with follow-up studies, 7 patients (5.0%) developed subsequent stroke ipsilateral to the CAO with mean occurrence 27.8 ± 39.0 months postdiagnosis. In addition, 5 patients (3.6%) developed other related symptoms, including global hypoperfusion (2.4%) and transient ischemic attack (1.2%). Of those, 95 patients with follow-up duplex ultrasound imaging, 6 (4.3%) underwent eventual ipsilateral intervention, including carotid endarterectomy (n = 4), transfemoral carotid artery stent (n = 1), and carotid bypass (n = 1), with mean occurrence 17.7 ± 23.7 months postdiagnosis. The aggregate rate of ipsilateral cerebrovascular accident, attributable neurologic symptoms, or ipsilateral intervention was 11.5%. Of 95 patients with follow-up duplex ultrasound imaging, 5 underwent subsequent duplex studies demonstrating ipsilateral patency, resulting in a 5.3% discrepancy rate between sequential duplex studies. All 6 patients undergoing intervention received periprocedural cross-sectional imaging (magnetic resonance angiography or computed tomography angiography). In 5 of these 6 patients, cross-sectional demonstrated severe stenosis rather than CAO, disputing prior duplex ultrasound findings. CONCLUSIONS: In this large, institutional cohort of patients with a CAO diagnosis on duplex ultrasound, a clinically meaningful subset of patients experienced cerebrovascular accident, related symptoms, or intervention. We also found a notable rate of temporal duplex discrepancies among patients with CAO diagnoses and discrepancies between CAO diagnosis per duplex ultrasound and findings on cross-sectional imaging for those patients who underwent intervention. These results suggest that use of a single duplex ultrasound as a sole diagnostic tool in CAO may not be sufficient and that physicians should consider close duplex ultrasound surveillance of these patients, potentially in conjunction with additional confirmatory imaging modalities. Further investigation into optimal workup and surveillance protocols for CAO is needed.

Non-Functional Carotid Body Tumors in Patients Without Somatic Mutations May Be Considered for Non-Operative Management.

BACKGROUND: Carotid Body Tumors (CBT) are rare neuroendocrine paragangliomas which are typically asymptomatic and benign, with a low rate of biochemical functionality. Historically, early surgical excision was recommended to prevent development of CBT-related complications. Yet, CBT resection can result in significant cranial nerve and vascular injuries. Recent work has shown successful primary observation without resection of non-carotid body, cranial paragangliomas with slow growth and low rate of neuropathies. We hypothesize that primary observation of CBT is safe and may be considered for majority of CBT. METHODS: Retrospective cohort study of patients at a multi-hospital healthcare system with radiologic identification and/or diagnostic or procedural billing codes for CBT (2000-2019). Tumor size (greatest diameter), associated symptoms, and interventions were recorded at the initial evaluation and throughout follow-up. Multivariable logistic regression investigated the risk of initial surgical resection. RESULTS: A total of 108 patients (mean age, 59 ± 19 years; 67% female), with 123 CBT (mean diameter 23 ± 12 mm; 52% right) were initially evaluated by otolaryngologists (51%), vascular surgeons (25%), neurosurgeons (8%), or other (16%) medical providers. Fity-five CBT were initially resected, 63 observed, and 5 irradiated. Initial resection was associated with younger age (adjusted odd ratios aOR, 0.95 [95% confidence intervals CI, 0.92-0.97]), male sex (aOR, 4.82 [95% CI, 1.47-15.75]), and evaluation by a vascular surgeon (aOR, 6.17 [95% CI, 2.04-18.63]). Overall median follow-up was 4.7 (IQR, 2.6-9.1) years. Initially observed CBT were on an average stable in size (mean 1 ± 5 mm/year), none became biochemically active, and 2 patients became symptomatic. At the final follow-up, 63 (51%) underwent surgical resection, 54 (44%) observation, and 6 (5%) radiation therapy. Of the 63 surgically resected CBT, 5 (8%) patients had malignant CBT of which 3 (60%) had known somatic mutations (polymerase epsilon [n = 1], succinate dehydrogenase-D gene [n = 2]). Thirty percent of CBT resections had in-hospital postoperative complications, notably including 1 stroke which occurred in an initially observed patient and 16 cranial nerve complications which all occurred in immediately resected patients. Three resected CBT locally recurred, only 1 of which had malignant pathology. CONCLUSIONS: Patients with newly diagnosed CBT require biochemical functionality and somatic mutation testing. In the absence of these findings, initial observation of CBTs with annual imaging and symptom monitoring may be considered an alternative to immediate resection which demonstrates a high risk of clinically meaningful postoperative complications.

Common iliac vein stenting for May-Thurner syndrome and subsequent pregnancy.

BACKGROUND: For women with left common iliac vein compression (ie, May-Thurner syndrome) who undergo venous stenting and subsequently become pregnant, concerns have been raised regarding a possible compromise of stent patency due to compression from the gravid uterus and the hypercoagulability induced by pregnancy. Only a small body of literature exists on this subject, and limited management guidelines are available. The present study was designed to evaluate the safety of iliac vein stenting for May-Thurner syndrome (MTS) with subsequent pregnancy. METHODS: Female patients who had undergone common iliac vein stenting at our center who were aged 18 to 45 years and had subsequently become pregnant were identified. A retrospective medical record review of eight eligible patients was conducted, recording the demographics, procedural characteristics, and anticoagulation strategies. The primary outcome evaluated was stent patency. RESULTS: All eight patients had undergone left common iliac vein stenting for MTS. A total of eight stents were placed, and all demonstrated duplex ultrasound patency throughout pregnancy and postpartum. Seven patients delivered healthy pregnancies, and one experienced a stillbirth. The clinical CEAP (clinical, etiologic, anatomic, pathophysiologic) class remained unchanged or improved from pregnancy to postpartum for all patients. The average age at stent placement was 31 ± 5 years, and the average interval from stent placement to pregnancy was 28 ± 19 months. One patient developed nonobstructive deep vein thrombosis (DVT) of the left femoral vein during pregnancy and was treated with therapeutic enoxaparin. The nonobstructive DVT did not compromise the iliac vein stent. Two patients received low-dose aspirin and prophylactic doses of enoxaparin, one for a history of DVT and factor V Leiden and one for a recent history of fertility treatment. The five remaining patients received no anticoagulation, three received low-dose aspirin, and two received no antiplatelet therapy. CONCLUSIONS: Common iliac vein stent patency was not compromised by subsequent pregnancy in our eight patients with MTS. Furthermore, the stents remained patent throughout pregnancy in patients receiving a wide range of anticoagulation and antiplatelet treatments, suggesting that no uniform therapeutic threshold exists and treatment should be individualized. For most patients, low-dose aspirin alone or no treatment was adequate. This could have implications for counseling women who require intervention for MTS and are of child-bearing age.

A single-center experience of anterior accessory saphenous vein endothermal ablation demonstrates safety and efficacy.

OBJECTIVE: Endothermal ablation is well-established for the treatment of the great and small saphenous veins. Data are lacking for treatment of the anterior accessory saphenous vein (AASV). The purpose of this study was to evaluate the safety and efficacy of AASV treatment using endothermal ablation. METHODS: This retrospective review included 314 limbs at a single academic institution from 2016 to 2018 using the institutional Vascular Quality Initiative database. All limbs had documented AASV reflux. Baseline characteristics were evaluated including age; sex; ethnicity; clinical, etiology, anatomy, pathophysiology classification; Venous Clinical Severity Score (VCSS); and vein diameter. Outcomes relating to procedure safety and efficacy included treatment modality and length, successful ablation on postoperative imaging, postprocedural clinical outcomes, incidence of endothermal heat-induced thrombosis (EHIT), and any postprocedural complication. RESULTS: A total of 314 consecutive limbs were identified from 2016 to 2018. The preprocedure VCSS scores were available for 312 limbs and averaged 6.13 ± 3.33. A history of varicose veins were reported in all limbs with 49.4% (n = 155) having previously undergone a procedure. The most common presenting symptom was mild edema in 52.5% (n = 165). Vein diameter and assessment of reflux were obtained by venous duplex ultrasound (DUS) examination. The largest AASV diameter was available for 304 limbs, averaging 7.93 ± 2.69 mm. Treatment modalities included radiofrequency ablation (RFA) in 59.2% (n = 186), endovenous laser ablation (EVLA) in 37.9% (n = 119), and isolated microphlebectomy in 2.9% (n = 9). In all, 38.5% (n = 121) of limbs underwent concomitant microphlebectomy at the time of EVLA. The total treatment length was obtained in 297 limbs, averaging 23.0 cm ± 12.0. Postoperatively, 94.6% of limbs (n = 297) were prescribed compression stockings. Postoperative DUS examination was performed in 312 limbs, revealing successful ablation in 96.5% (n = 303) with 2 limbs (0.6%) developing an EHIT, both treated with therapeutic enoxaparin for 1 week. Repeat DUS examination revealed thrombus resolution in one limb; the other patient was lost to follow-up. VCSS scores after the procedure were available for 145 limbs and averaged 4.45 ± 2.31. This was a statistically significant decrease from preprocedure VCSS scores (P < .01). Average duration of follow-up was 2.2 years, with two limbs lost to follow-up. Of the nine limbs (3.5%) whose initial procedure failed, five (56%) were treated using RFA and four (44%) were treated using EVLA. There were no other postoperative complications. CONCLUSIONS: Our experience over a 3-year period for treating the AASV shows it to be safe and effective in a broad range of disease severity with an improvement in VCSS and a low incidence of EHIT. Additionally, RFA and EVLA exhibit similar treatment efficacy. Long-term follow-up data are needed.

Venous thromboembolism in a patient with an uncommon etiology of May-Thurner syndrome.

May-Thurner syndrome (MTS) consists of common iliac vein compression from an extrinsic source. Patients with MTS can present with a variety of symptoms, potentially making the diagnosis difficult. Classically, MTS will result in left iliac vein compression from the right iliac artery. In rare cases, it can be secondarily caused by compression from other anatomic structures in the pelvis. We present the case of a 43-year-old woman with MTS with iliofemoral deep vein thrombosis and pulmonary embolism caused by a large uterine leiomyoma. Our findings underscore the need to consider various etiologies of venous compression in patients with extensive unilateral venous thromboembolism.

Hepatorenal syndrome from an ilio-iliac arteriovenous fistula: A rare complication from an endoleak.

Arteriovenous fistula is a rare and often unrecognized complication of aneurysms, with a varied and frequently inconsistent presentation. We present the case of an ilio-iliac arteriovenous fistula formation in a 71-year-old man associated with a type III endoleak after endovascular iliac branch repair. Because of rapidly progressing congestive heart failure and hepatorenal syndrome, we performed urgent endovascular repair with successful endoleak exclusion. After the procedure, the patient demonstrated a remarkably rapid and complete recovery.

Deep vein thrombosis in hospitalized patients with coronavirus disease 2019.

OBJECTIVE: The pandemic of coronavirus disease 2019 (COVID-19) has caused devastating morbidity and mortality worldwide. In particular, thromboembolic complications have emerged as a key threat for patients with COVID-19. We assessed our experience with deep vein thrombosis (DVT) in patients with COVID-19. METHODS: We performed a retrospective analysis of all patients with COVID-19 who had undergone upper or lower extremity venous duplex ultrasonography at an academic health system in New York City from March 3, 2020 to April 12, 2020 with follow-up through May 12, 2020. A cohort of hospitalized patients without COVID-19 (non-COVID-19) who had undergone venous duplex ultrasonography from December 1, 2019 to December 31, 2019 was used for comparison. The primary outcome was DVT. The secondary outcomes included pulmonary embolism, in-hospital mortality, admission to the intensive care unit, and antithrombotic therapy. Multivariable logistic regression was performed to identify the risk factors for DVT and mortality. RESULTS: Of 443 patients (COVID-19, n = 188; and non-COVID-19, n = 255) who had undergone venous duplex ultrasonography, the COVID-19 cohort had had a greater incidence of DVT (31% vs 19%; P = .005) than had the non-COVID-19 cohort. The incidence of pulmonary embolism was not significantly different statistically between the COVID-19 and non-COVID-19 cohorts (8% vs 4%; P = .105). The DVT location in the COVID-19 group was more often distal (63% vs 29%; P < .001) and bilateral (15% vs 4%; P < .001). The duplex ultrasound findings had a significant impact on the antithrombotic plan; 42 patients (72%) with COVID-19 in the DVT group had their therapy escalated and 49 (38%) and 3 (2%) had their therapy escalated and deescalated in the non-DVT group, respectively (P < .001). Within the COVID-19 cohort, the D-dimer level was significantly greater in the DVT group at admission (2746 ng/mL vs 1481 ng/mL; P = .004) and at the duplex examination (6068 ng/mL vs 3049 ng/mL; P < .01). On multivariable analysis, male sex (odds ratio [OR], 2.27; 95% confidence interval [CI], 1.06-4.87; P = .035), intensive care unit admission (OR, 3.42; 95% CI, 1.02-11.44; P = .046), and extracorporeal membrane oxygenation (OR, 5.5; 95% CI, 1.01-30.13; P = .049) were independently associated with DVT. CONCLUSIONS: Given the high incidence of venous thromboembolic events in this population, we support the decision to empirically initiate therapeutic anticoagulation for patients with a low bleeding risk and severe COVID-19 infection. Duplex ultrasonography should be reserved for patients with a high clinical suspicion of venous thromboembolism for whom anticoagulation therapy could result in life-threatening consequences. Further study of patients with COVID-19 is warranted to elucidate the etiology of vascular thromboembolic events and guide the prophylactic and therapeutic interventions for these patients.