Acute Renal Artery Embolism in SARS-CoV-2 Infection: A Case Report.

Background Coronavirus disease 2019 (COVID-19) is identied as the pneumonia and acute respiratory distress syndrome caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV2). The intravascular thrombotic phenomena related to the COVID-19 are emerging as an important complication that contribute to signicant mortality. We present a 62-year-old man with severe COVID-19 and type 2 diabetes. After symptomatic and supportive treatment, the respiratory function was gradually improved. However, the patient suddenly developed abdominal pain, and the enhanced CT scan revealed acute left renal artery embolism. Given the risk of surgery and the duration of the disease, clopidogrel and heparin sodium were included in the subsequent treatment. Later, the abdominal pain and hypercoagulable state disappeared, and the effect was still satisfactory.

the risk of surgery and the duration of the disease, clopidogrel and heparin sodium were included in the subsequent treatment. Later, the abdominal pain and hypercoagulable state disappeared, and the effect was still satisfactory.

Conclusions
This report clari es the challenges posed by embolism complications in the management of COVID-19 patients. Thrombosis is at a high risk in patients with severe COVID-19 pneumonia because of hypercoagulable state, blood stasis and endothelial injury. Thrombotic events caused by hypercoagulation status secondary to vascular endothelial injury deserves our attention. Because timely anticoagulation can reduce the risk of early complications, as illustrated in this case report. Background COVID-19 has been declared as a pandemic by World Health Organization in March, 2020. Recent studies show that severe COVID-19 pneumonia is associated with a coagulopathic state and may increase the risk of thrombotic complications [1]. The current common thrombotic complications mainly include venous thrombosis events, pulmonary thrombosis, and myocardial infarction. However, we have noted that reports of embolization events that occur in renal arteries are rare. We present a case of acute renal artery embolism in a SARS-CoV-2-positive patient.

Case Presentation
A 62-year-old man with a history of type 2 diabetes presented with fever that started ve days ago. Cough, fatigue, or abdominal pain were not present. At admission, the body temperature was 36.7 °C, and the patient was diagnosed with SARS-CoV-2 infection by reverse transcriptase-polymerase chain reaction (RT-PCR) assay. Vital signs on presentation revealed heart rate of 76 beats/minute, respiratory rate of 20 breaths/minute, and blood pressure of 117/65 mmHg. A chest computed tomography scan showed ground glass-like shadows multiple consolidations in the both upper lobes (Fig. 1). Initial peripheral blood samples revealed that there was no hypercoagulability (Table 1). According to the fth edition of Chinese New Coronavirus (2019-nCoV) Infection Treatment Plan Guide [2], the coronavirus pneumonia diagnosed was classi ed as mild type. After admission, he was given routine antiviral and glycemic management of diabetes. Traditional Chinese medicine was used as supportive treatments. Three days later, the patient developed shortness of breath and the symptom gradually worsened. The blood gas analysis showed an oxygenation index result of 172. Subsequently, the treatment regimen was switched to methylprednisolone 80 mg per day and ceftriaxone in accordance with guidelines for severe cases. After symptomatic and supportive treatments, the patient's respiratory function improved and he was diagnosed with mild COVID-19. On day 12 of hospitalization, the patient reported sudden-onset severe pain in the left waist. The Peripheral blood examination at that time suggested signi cantly elevated d-dimer level of 1008 ng/ml (Table 1). Abdominal and urinary color doppler ultrasound showed no abnormalities. Two days later, the enhanced CT scan revealed the left renal artery embolism and threatening ischemia (Fig. 2). Given the risk of surgery and the duration of the disease, the patient underwent clopidogrel 300 mg per day and heparin sodium 0.4 ml every 12 hours.
After that, the dosage was adjusted according to the change of laboratory parameters. On blood examination one week later the level of D-dimer was normal, and the pain in the left waist had completely resolved.

Discussion And Conclusions
In this case, acute renal artery embolism suddenly occurred during the treatment of COVID-19 and subsequently led to left renal threatening ischemia. The laboratory test indicating thrombotic complications was elevated D-dimer. Previous studies have shown that elevated D-dimer was a risk factor for death in patients with SARS-CoV-2 infection, especially in elderly patients [3,4]. The hypercoagulation status of COVID-19 and the subsequent series of vascular complications are a vital topic that is currently emerging [5]. The question of anticoagulant therapy at prophylaxis dose or even higher was subsequently raised [6]. It has been suggested that immune-mediated reaction or direct viral infection of the endothelium will lead to recruitment of immune cells, which may develop into extensive endothelial dysfunction [7]. Angiotensin converting enzyme 2 (ACE2) receptors are expressed in organs including lung, heart, kidney and intestine. Vascular endothelial cells also express angiotensin converting enzyme 2 receptor. And the virus can directly infect endothelial cells by converting enzyme 2 and cause diffuse endothelial in ammation [8]. SARS-CoV-2 infection can develop into acute respiratory distress syndrome. Similar to other viral infections, early cytokine storms are caused by overproduction of response proin ammatory cytokines including tumor necrosis factor, interleukin-6 and interleukin-1 β, resulting in an increased risk of multiorgan failure and vascular hyperpermeability [9]. The main function of thrombin in the immune response is to promote the formation of clots by activating platelets and converting brinogen to brin. However, it is worth noting that the cellular effect of thrombin, mainly par-1 (proteinase-activated receptors), can further enhance in ammation [10]. Protein C system, tissue factor pathway inhibitor and antithrombin are defective during in ammation, which impairs the coagulantanticoagulant balance and leads to the formation of microthrombus [11]. The hypercoagulation status of blood caused by the infection of SARS-CoV-2 can lead to a variety of intravascular thrombotic phenomena, ranging from limited venous and arterial thrombosis to fatal disseminated intravascular coagulation.
Thrombotic events caused by hypercoagulation status secondary to vascular endothelial injury deserves our attention. Because timely anticoagulation can reduce the risk of early complications.