Endovascular Treatment of Basilar Artery Occlusion: What Can We Learn from the Results?

Background and Objectives: Current guidelines lack specific endovascular treatment (EVT) recommendations for posterior circulation stroke (PCS). The results of earlier studies are controversial. We aimed to compare early hospital outcomes of stroke caused by large-vessel occlusion (LVO) treated with EVT or bridging therapy (BT) in anterior circulation stroke (ACS) versus PCS (middle cerebral artery occlusion (MCAO) and basilar artery occlusion (BAO), and establish the risk factors for poor outcome. Materials and Methods: we analyzed the data of 279 subjects treated with EVT due to LVO-caused stroke in a comprehensive stroke centre in 2015−2021. The primary outcome was hospital mortality, secondary outcomes were National Institutes of Health Stroke Scale (NIHSS) after 24 h, early neurological deterioration, futile recanalization (FR), the ambulatory outcome at discharge, and complications. Results: BAO presented with higher baseline NIHSS scores (19 vs. 14, p < 0.001), and longer door-to-puncture time (93 vs. 82 min, p = 0.034), compared to MCAO. Hospital mortality and the percentage of FR were the same in BAO and almost two times higher than in MCAO (20.0% vs. 10.3%, p = 0.048), other outcomes did not differ. In BAO, unsuccessful recanalization was the only significant predictor of the lethal outcome, though there were trends for PAD and RF predicting lethal outcome. A trend for higher risk of symptomatic intracranial hemorrhage (sICH) was observed in the BAO group when BT was applied. Nevertheless, neither BT nor sICH predicted lethal outcomes in the BAO group. Conclusions: Compared to the modern gold standard of EVT in the ACS, early outcomes in BAO remain poor, there is a substantial amount of FR. Nevertheless, unsuccessful recanalization remains the strongest predictor of lethal outcomes. BT in PCS might pose a higher risk for sICH, but not the lethal outcome, although this finding requires further investigation in larger trials.

Multiple Sites of Arterial Thrombosis in A 35-Year Old Patient after ChAdOx1 (AstraZeneca) Vaccination, Requiring Emergent Femoral and Carotid Surgical Thrombectomy.

BACKGROUND: Vaccine Induced Thrombotic Thrombocytopenia (VITT) is a rare complication following ChAdOx1 (AstraZeneca) vaccination. Venous thrombosis in unusual sites such as splachnic or intracranial thrombosis, is the commonest manifestation. CASE REPORT: We report a 35-year-old male patient who presented with acute left leg ischemia and thrombocytopenia 11-days after vaccination requiring emergent thrombectomy. During work-up, a localized thrombus was detected in the left carotid bifurcation mandating carotid thrombectomy. Localized right iliac thrombus causing a non-limiting flow stenosis was treated conservatively. The platelet aggregating capacity of patient's plasma was confirmed in a functional assay, thereby establishing VITT. CONCLUSION: To the best of our knowledge this is the first case presenting multiple arterial thromboses requiring surgical treatment after ChAdOx1 vaccination.

Adventitial Microcirculation Is a Major Target of SARS-CoV-2-Mediated Vascular Inflammation.

We report the case of a 77-year-old woman affected by coronavirus disease-19 (COVID-19) who developed an occlusive arterial disease of the lower limb requiring a left leg amputation. We studied the mechanisms of vascular damage by SARS-CoV-2 by means of a comprehensive multi-technique in situ analysis on the diseased popliteal arterial district, including immunohistochemistry (IHC), transmission electron microscopy (TEM) and miRNA analysis. At histological analyses, we observed a lymphocytic inflammatory infiltrate, oedema and endothelialitis of adventitial vasa vasorum while the media was normal and the intima had only minor changes. The vasa vasorum expressed the ACE2 receptor and factor VIII; compared with the controls, VEGFR2 staining was reduced. TEM analyses showed endothelial injury and numerous Weibel-Palade bodies in the cytoplasm. No coronavirus particle was seen. IL-6 protein and mRNA, together with miR-155-5p and miRs-27a-5p, which can target IL-6, were significantly increased compared with that in the controls. Our case report suggests an involvement of adventitial artery microcirculation by inflammation in the course of COVID-19. Without evident signs of current infection by SARS-CoV-2, endothelial cells show a spectrum of structural and functional alterations that can fuel the cardiovascular complications observed in people infected with SARS-CoV-2.

Two-year single centre results with covered endovascular reconstruction of aortic bifurcation (CERAB) in the treatment of extensive aorto-iliac occlusive disease.

OBJECTIVE: To report the results of a single-centre in the treatment of extensive aorto-iliac occlusive disease (AIOD) by the covered endovascular reconstruction of aortic bifurcation (CERAB) technique. METHODS: A retrospective analysis was conducted on data obtained from the review of medical charts of all consecutive patients treated with CERAB technique for AIOD between January 2016 and December 2019 in San Giovanni-Addolorata Hospital (Rome, Italy). Clinical examination, duplex ultrasound with ankle-brachial index measurement and contrast-enhanced computed tomography angiography were performed preoperatively. A clinical and ultrasound follow-up was carried out at one month and then half yearly after the intervention to evaluate patients' clinical status, limb salvage, target lesion revascularization rate, primary and secondary patency rate. RESULTS: During the study period, 24 patients (14 men, 58.3%; 10 women, 41.7%; median age 59 years, range 37-79 years) underwent CERAB for AIOD (TASC II C 29.2%, TASC II D 70.8%). Indications for treatment were: intermittent claudication in 18 patients (75%) and critical limb ischemia in 6 (25%). Technical success was achieved in all cases. Perioperative minor complications occurred in three cases (12.5%). One patient reported an intraoperative iliac rupture requiring adjunctive covered stenting. Median hospital length of stay was two days (range 1-9). No patient died perioperatively nor at the last follow-up. At a median follow-up of 18 months (range 6-48 months), mean ankle-brachial index increased significantly (from 0.62 ± 0.15 before the procedure to 0.84 ± 0.18) (P < 0.001) and target lesion revascularization rate was 12.5%. At two years, the limb salvage rate was 100%, and primary and secondary patency rates were 87.5% and 100%, respectively. CONCLUSION: CERAB technique demonstrated to be effective at the mid-term follow-up with low rate of complications and short length of stay. Long-term results and more robust data are needed to affirm this technique as the first-line treatment for extensive AIOD. However, it could become the preferred option especially in fragile patients and during contemporary COVID-19 pandemic due to the current limitations in vascular and critical care bed capacity.

Arterial Thrombotic Sequalae After Covid-19: Mind the Gap.

Investigations have shown that infection from the severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) is responsible also for initiating severe inflammatory responses that can lead macrovascular and microvascular thrombosis. Several studies have already described acute limb ischemia and peripheral arterial disease in critically ill patients with Coronavirus disease 2019 (Covid-19), as well as coronary artery disease and ischemic stroke as a manifestation usually associated with respiratory distress. However, what still remains unclear is how long inflammation and thrombotic derangements can last after recovery from the symptoms of Covid-19. Hence, in this article we report 3 cases of arterial thrombotic sequalae after this viral infection. To the best of our knowledge, this is the first cases' series that had described different delayed vascular arterial complications, which occurred after the index infection, with a negative nasopharyngeal swab and Covid-19 systemic symptoms resumption. A better understanding of the coagulopathy in Covid-19 could have an essential role to guide prevention and treatment of arterial thromboembolic events, both during and after the viral infection. Further investigations are required to confirm these data and to estabilish the type, dose and duration of anticoagulant/antiplatelet therapy not just during but also after Covid-19 infection.

Percutaneous Revascularization for COVID-19 Induced Spontaneous Arterial Thrombosis.

The optimal management strategy of acute limb ischemia in non-ventilated patients with COVID-19 is uncertain. We propose that non-ventilated patients who develop COVID-19 related spontaneous arterial thrombosis with associated limb threat may be best suited with percutnaeous revascularization to achieve limb salvage. Herein we describe 5 cases of patients who had severely threatened limbs with complete thrombosis of all 3 tibial arteries who were treated with percutaneous revascularization. All 5 patients were felt to be facing inevitable amputation without revascularization should they survive their COVID hospitalization. We were able to achieve limb salvage in all 5 patients selected for therapy, although 2 ultimately succumbed to respiratory failure.

Severe acute respiratory syndrome coronavirus 2-induced acute aortic occlusion: a case report.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 infection can lead to a constellation of viral and immune symptoms called coronavirus disease 2019. Emerging literature increasingly supports the premise that severe acute respiratory syndrome coronavirus 2 promotes a prothrombotic milieu. However, to date there have been no reports of acute aortic occlusion, itself a rare phenomenon. We report a case of fatal acute aortic occlusion in a patient with coronavirus disease 2019. CASE REPORT: A 59-year-old Caucasian male with past medical history of peripheral vascular disease presented to the emergency department for evaluation of shortness of breath, fevers, and dry cough. His symptoms started 5-7 days prior to the emergency department visit, and he received antibiotics in the outpatient setting without any effect. He was found to be febrile, tachypneic, and hypoxemic. He was placed on supplemental oxygen via a non-rebreather mask. Chest X-ray showed multifocal opacifications. Intravenous antibiotics for possible pneumonia were initiated. Hydroxychloroquine was initiated to cover possible coronavirus disease 2019 pneumonia. During the hospitalization, the patient became progressively hypoxemic, for which he was placed on bilevel positive airway pressure. D-dimer, ferritin, lactate dehydrogenase, and C-reactive protein were all elevated. Severe acute respiratory syndrome coronavirus 2 reverse transcription polymerase chain reaction was positive. On day 3, the patient was upgraded to the intensive care unit. Soon after he was intubated, he developed a mottled appearance of skin, which extended from his bilateral feet up to the level of the subumbilical plane. Bedside ultrasound revealed an absence of flow from the mid-aorta to both common iliac arteries. The patient was evaluated emergently by vascular surgery. After a discussion with the family, it was decided to proceed with comfort-directed care, and the patient died later that day. DISCUSSION: Viral infections have been identified as a source of prothrombotic states due to direct injury of vascular tissue and inflammatory cascades. Severe acute respiratory syndrome coronavirus 2 appears to follow a similar pattern, with numerous institutions identifying elevated levels of thrombotic complications. We believe that healthcare providers should be aware of both venous and arterial thrombotic complications associated with coronavirus disease 2019, including possible fatal outcome.

Early experience with arterial thromboembolic complications in patients with COVID-19.

BACKGROUND: Little is known about the arterial complications and hypercoagulability associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We sought to characterize our experience with arterial thromboembolic complications in patients with hospitalized for coronavirus disease 2019 (COVID-19). METHODS: All patients admitted from March 1 to April 20, 2020, and who underwent carotid, upper, lower and aortoiliac arterial duplex, computed tomography angiogram or magnetic resonance angiography for suspected arterial thrombosis were included. A retrospective case control study design was used to identify, characterize and evaluate potential risk factors for arterial thromboembolic disease in SARS-CoV-2 positive patients. Demographics, characteristics, and laboratory values were abstracted and analyzed. RESULTS: During the study period, 424 patients underwent 499 arterial duplex, computed tomography angiogram, or magnetic resonance angiography imaging studies with an overall 9.4% positive rate for arterial thromboembolism. Of the 40 patients with arterial thromboembolism, 25 (62.5%) were SARS-CoV-2 negative or admitted for unrelated reasons and 15 (37.5%) were SARS-CoV-2 positive. The odds ratio for arterial thrombosis in COVID-19 was 3.37 (95% confidence interval, 1.68-6.78; P = .001). Although not statistically significant, in patients with arterial thromboembolism, patients who were SARS-CoV-2 positive compared with those testing negative or not tested tended to be male (66.7% vs 40.0%; P = .191), have a less frequent history of former or active smoking (42.9% vs 68.0%; P = .233) and have a higher white blood cell count (14.5 vs 9.9; P = .208). Although the SARS-CoV-2 positive patients trended toward a higher the neutrophil-to-lymphocyte ratio (8.9 vs 4.1; P = .134), creatinine phosphokinase level (359.0 vs 144.5; P = .667), C-reactive protein level (24.2 vs 13.8; P = .627), lactate dehydrogenase level (576.5 vs 338.0; P = .313), and ferritin level (974.0 vs 412.0; P = .47), these differences did not reach statistical significance. Patients with arterial thromboembolic complications and SARS-CoV-2 positive when compared with SARS-CoV-2 negative or admitted for unrelated reasons were younger (64 vs 70 years; P = .027), had a significantly higher body mass index (32.6 vs 25.5; P = .012), a higher d-dimer at the time of imaging (17.3 vs 1.8; P = .038), a higher average in hospital d-dimer (8.5 vs 2.0; P = .038), a greater distribution of patients with clot in the aortoiliac location (5 vs 1; P = .040), less prior use of any antiplatelet medication (21.4% vs 62.5%; P = .035), and a higher mortality rate (40.0% vs 8.0%; P = .041). Treatment of arterial thromboembolic disease in COVID-19 positive patients included open thromboembolectomy in six patients (40%), anticoagulation alone in four (26.7%), and five (33.3%) did not require or their overall illness severity precluded additional treatment. CONCLUSIONS: Patients with SARS-CoV-2 are at risk for acute arterial thromboembolic complications despite a lack of conventional risk factors. A hyperinflammatory state may be responsible for this phenomenon with a preponderance for aortoiliac involvement. These findings provide an early characterization of arterial thromboembolic disease in SARS-CoV-2 patients.

Bilateral Large Vessel Occlusion Causing Massive Ischemic Stroke in a COVID-19 Patient.

The case of a 70-year-old male presenting an ischemic stroke related to COVID-19 infection is described. He was initially admitted to the hospital with respiratory insufficiency syndrome secondary to pneumonia caused by SARS Co2. In the next days, he developed rapid neurological deterioration characterized by drowsiness which progressed to deep coma. D-dimer was elevated. Brain CT scan showed bilateral massive ischemic stroke located in the anterior circulation, CT angiogram showed occlusion in the left internal carotid artery and the right middle cerebral artery. The deterioration of the patient continued and he subsequently died. Large vessel occlusion has been reported in COVID-19 patients, but this clinical presentation is usually unilateral. Cases of bilateral occlusion of large vessels have not been previously reported in COVID-19 patients. This report shows that bilateral massive stroke may occur in COVID-19 cases and it should be suspected in patients who show rapid neurological deterioration without focal deficits.

Acute aortoiliac occlusion in a patient with novel coronavirus disease-2019.

The severe acute respiratory syndrome novel coronavirus-2 pandemic is affecting almost every country in the world. Even if the major symptoms of coronavirus disease-2019 are respiratory, different symptoms at presentation are now recognized. Venous thromboembolism has been reported in infected patients and few but increasing cases of arterial thrombosis have been described. We report a case of acute aortoiliac and lower limb artery occlusions in a patient presenting with severe coronavirus disease-2019 infection. The mechanism of the occlusion seemed to be distal embolization from a floating thrombus in the aortic arch caused by a major inflammatory state and virus infection. The patient underwent aortoiliac and lower limb artery mechanical thrombectomy, but required unilateral major amputation.

COVID-19 and Major Organ Thromboembolism: Manifestations in Neurovascular and Cardiovascular Systems.

COVID-19, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been shown to cause multisystemic damage. We undertook a systematic literature review and comprehensive analysis of a total of 55 articles on arterial and venous thromboembolism in COVID-19 and articles on previous pandemics with respect to thromboembolism and compared the similarities and differences between them. The presence of thrombosis in multiple organ systems points to thromboembolism being an integral component in the pathogenesis of this disease. Thromboembolism is likely to be the main player in the morbidity and mortality of COVID -19 in which the pulmonary system is most severely affected. We also hypothesize that D-dimer values could be used as an early marker for prognostication of disease as it has been seen to be raised even in the pre-symptomatic stage. This further strengthens the notion that thromboembolism prevention is necessary. We also examined literature on the neurovascular and cardiovascular systems, as the manifestation of thromboembolic phenomenon in these two systems varied, suggesting different pathophysiology of damage. Further research into the role of thromboembolism in COVID-19 is important to advance the understanding of the virus, its effects and to tailor treatment accordingly to prevent further casualties from this pandemic.

COVID-19 Infection and Arterial Thrombosis: Report of Three Cases.

Thrombotic complications associated with coronavirus disease 2019 (COVID-19) have been described; these have mainly included venous thromboembolic events. Limited literature is available regarding arterial thrombosis. Acute limb ischemia is associated with severe complications that can result in significant morbidity and mortality. Herein, we report 3 cases of COVID-19 infection complicated by arterial thrombosis in the form of acute limb ischemia. Our case series adds to the limited literature regarding arterial thrombosis.

Systemic Thrombolysis as Initial Treatment of COVID-19 Associated Acute Aortoiliac and Lower Extremity Arterial Thrombosis.

SARS-CoV-2 (COVID-19) patients with associated thromboembolic events have demonstrated poor outcomes despite the use of anticoagulation therapy and surgical intervention. We present a COVID-19 patient with acute limb ischemia, secondary to extensive thrombosis of an aortic aneurysm, iliac arteries, and infrainguinal arteries. Initial treatment with systemic thrombolysis, which restored patency of the aortoiliac occlusion, was followed by open thrombectomies of the infrainguinal occlusions.

Large vessel stroke in six patients following SARS-CoV-2 infection: a retrospective case study series of acute thrombotic complications on stable underlying atherosclerotic disease.

BACKGROUND AND PURPOSE: Ischaemic stroke has been described in association with COVID-19. Several pathophysiological mechanisms have been suggested, i.e. prothrombotic state, cardiac injury etc. It was sought to assess the potential association between ischaemic stroke associated with SARS-CoV-2 infection and underlying atherosclerotic lesions. METHODS: A retrospective analysis of stroke related to large vessel occlusion was conducted amongst patients with SARS-CoV-2 infection and underlying mild atherosclerotic disease, between 19 March and 19 April 2020 in six different stroke centers in the Île-de France area, France. RESULTS: The median age was 52 years, median body mass index was 29.5 kg/m2 . All patients displayed previous vascular risk factors such as high blood pressure, diabetes, dyslipidemia or body mass index > 25. The delay between the first respiratory symptoms of COVID-19 and stroke was 11.5 days. At baseline, all had tandem occlusions, i.e. intracerebral and extracerebral thrombus assessed with computed tomography or magnetic resonance imaging. Cases displayed a large thrombus in the cervical carotid artery with underlying mild non-stenosing atheroma, after an etiological workup based on angio-computed tomography or magnetic resonance imaging and/or cervical echography. CONCLUSION: Our study should alert clinicians to scrutinize any new onset of ischaemic stroke during COVID-19 infection, mainly in patients with vascular risk factors or underlying atherosclerotic lesions.

Association of Coronavirus Disease (COVID-19) With Large Vessel Occlusion Strokes: A Case-Control Study.

BACKGROUND. An increase in frequency of acute ischemic strokes has been observed among patients presenting with acute neurologic symptoms during the coronavirus disease (COVID-19) pandemic. OBJECTIVE. The purpose of this study was to investigate the association between COVID-19 and stroke subtypes in patients presenting with acute neurologic symptoms. METHODS. This retrospective case-control study included patients for whom a code for stroke was activated from March 16 to April 30, 2020, at any of six New York City hospitals that are part of a single health system. Demographic data (age, sex, and race or ethnicity), COVID-19 status, stroke-related risk factors, and clinical and imaging findings pertaining to stroke were collected. Univariate and multivariate analyses were conducted to evaluate the association between COVID-19 and stroke subtypes. RESULTS. The study sample consisted of 329 patients for whom a code for stroke was activated (175 [53.2%] men, 154 [46.8%] women; mean age, 66.9 ± 14.9 [SD] years). Among the 329 patients, 35.3% (116) had acute ischemic stroke confirmed with imaging; 21.6% (71) had large vessel occlusion (LVO) stroke; and 14.6% (48) had small vessel occlusion (SVO) stroke. Among LVO strokes, the most common location was middle cerebral artery segments M1 and M2 (62.0% [44/71]). Multifocal LVOs were present in 9.9% (7/71) of LVO strokes. COVID-19 was present in 38.3% (126/329) of the patients. The 61.7% (203/329) of patients without COVID-19 formed the negative control group. Among individual stroke-related risk factors, only Hispanic ethnicity was significantly associated with COVID-19 (38.1% of patients with COVID-19 vs 20.7% of patients without COVID-19; p = 0.001). LVO was present in 31.7% of patients with COVID-19 compared with 15.3% of patients without COVID-19 (p = 0.001). SVO was present in 15.9% of patients with COVID-19 and 13.8% of patients without COVID-19 (p = 0.632). In multivariate analysis controlled for race and ethnicity, presence of COVID-19 had a significant independent association with LVO stroke (odds ratio, 2.4) compared with absence of COVID-19 (p = 0.011). CONCLUSION. COVID-19 is associated with LVO strokes but not with SVO strokes. CLINICAL IMPACT. Patients with COVID-19 presenting with acute neurologic symptoms warrant a lower threshold for suspicion of large vessel stroke, and prompt workup for large vessel stroke is recommended.

Viral Coagulopathy in Patients With COVID-19: Treatment and Care.

COVID-19 has proven to be particularly challenging given the complex pathogenesis of SARS-CoV-2. Early data have demonstrated how the host response to this novel coronavirus leads to the proliferation of pro-inflammatory cytokines, massive endothelial damage, and generalized vascular manifestations. While SARS-CoV-2 primarily targets the upper and lower respiratory tract, other organ systems are also affected. SARS-CoV-2 relies on 2 host cell receptors for successful attachment: angiotensin-converting enzyme 2 and transmembrane protease serine 2. Clinicopathologic reports have demonstrated associations between severe COVID-19 and viral coagulopathy, resulting in pulmonary embolism; venous, arterial, and microvascular thrombosis; lung endothelial injury; and associated thrombotic complications leading to acute respiratory distress syndrome. Viral coagulopathy is not novel given similar observations with SARS classic, including the consumption of platelets, generation of thrombin, and increased fibrin degradation product exhibiting overt disseminated intravascular coagulation-like syndrome. The specific mechanism(s) behind the thrombotic complications in COVID-19 patients has yet to be fully understood. Parenteral anticoagulants, such as heparin and low-molecular-weights heparins, are widely used in the management of COVID-19 patients. Beyond the primary (anticoagulant) effects of these agents, they may exhibit antiviral, anti-inflammatory, and cytoprotective effects. Direct oral anticoagulants and antiplatelet agents are also useful in the management of these patients. Tissue plasminogen activator and other fibrinolytic modalities may also be helpful in the overall management. Catheter-directed thrombolysis can be used in patients developing pulmonary embolism. Further investigations are required to understand the molecular and cellular mechanisms involved in the pathogenesis of COVID-19-associated thrombotic complications.

COVID-19: Coagulopathy, Risk of Thrombosis, and the Rationale for Anticoagulation.

The novel coronavirus infection (COVID-19) is caused by the new coronavirus SARS-CoV-2 and is characterized by an exaggerated inflammatory response that can lead to severe manifestations such as adult respiratory syndrome, sepsis, coagulopathy, and death in a proportion of patients. Among other factors and direct viral effects, the increase in the vasoconstrictor angiotensin II, the decrease in the vasodilator angiotensin, and the sepsis-induced release of cytokines can trigger a coagulopathy in COVID-19. A coagulopathy has been reported in up to 50% of patients with severe COVID-19 manifestations. An increase in d-dimer is the most significant change in coagulation parameters in severe COVID-19 patients, and progressively increasing values can be used as a prognostic parameter indicating a worse outcome. Limited data suggest a high incidence of deep vein thrombosis and pulmonary embolism in up to 40% of patients, despite the use of a standard dose of low-molecular-weight heparin (LMWH) in most cases. In addition, pulmonary microvascular thrombosis has been reported and may play a role in progressive lung failure. Prophylactic LMWH has been recommended by the International Society on Thrombosis and Haemostasis (ISTH) and the American Society of Hematology (ASH), but the best effective dosage is uncertain. Adapted to the individual risk of thrombosis and the d-dimer value, higher doses can be considered, especially since bleeding events in COVID-19 are rare. Besides the anticoagulant effect of LMWH, nonanticoagulant properties such as the reduction in interleukin 6 release have been shown to improve the complex picture of coagulopathy in patients with COVID-19.

First, do no harm: bilateral radial artery occlusion in a COVID-19 patient.

OBJECTIVE: Objective of this case report is to draw attention to a less known thrombotic complication associated with COVID-19, i.e., thrombosis of both radial arteries, with possible (long-term) consequences. THE CASE: In our COVID-19 ICU a 49-year-old male patient was admitted, with past medical history of obesity, smoking and diabetes, but no reported atherosclerotic complications. The patient had been admitted with severe hypoxemia and multiple pulmonary emboli were CT-confirmed. ICU-treatment included mechanical ventilation and therapeutic anticoagulation. Preparing the insertion of a new radial artery catheter for invasive blood pressure measurement and blood sampling, we detected that both radial arteries were non-pulsating and occluded: (a) Sonography showed the typical anatomical localization of both radial and ulnar arteries. However, Doppler-derived flow-signals could only be obtained from the ulnar arteries. (b) To test collateral arterial supply of the hand, a pulse-oximeter was placed on the index finger. Thereafter, the ulnar artery at the wrist was compressed. This compression caused an immediate loss of the finger's pulse-oximetry perfusion signal. The effect was reversible upon release of the ulnar artery. (c) To test for collateral perfusion undetectable by pulse-oximetry, we measured regional oxygen saturation (rSO2) of the thenar muscle by near-infrared spectroscopy (NIRS). Confirming our findings above, ulnar arterial compression demonstrated that thenar rSO2 was dependent on ulnar artery flow. The described development of bilateral radial artery occlusion in a relatively young and therapeutically anticoagulated patient with no history of atherosclerosis was unexpected. CONCLUSIONS: Since COVID-19 patients are at increased risk for arterial occlusion, it appears advisable to meticulously check for adequacy of collateral (hand-) perfusion, avoiding the harm of hand ischemia if interventions (e.g., catheterizations) at the radial or ulnar artery are intended.