CASE 2

A 70-year-old male patient (PADUA index: 5, Caprini index: 7) was confirmed as having COVID-19 disease when he received a routine preoperative pulmonary CT scan due to arterial and venous thrombosis in the right extremity. After 25 days of chronic ischemia, there was dry gangrene of his right thigh (Fig. 2A ). On admission to hospital, physical examination showed that his right lower limb appeared swollen and tender; displayed cyanotic change with a diminished dorsalis pedis pulse. Color US detection determined that he was suffering from a right iliac arterial and venous embolism. A series of other poorly prognostic symptoms, such as left toe ischemia (Fig. 2B ) and left lower extremity inter-muscular venous thrombosis were also found. His abdominal aorta and left iliac arteries remained unobstructed. His only past medical history of note was surgery for lung cancer four years previously.
Initial laboratory tests (Table 2 ) showed a high CRP (65.85 mg/L), white blood cell (9.83 G/L), neutrophil count (7.49 G/L), alanine transaminase (ALT) (127 U/L), aspartate transaminase (AST) (119 U/L) levels, D-dimer (6.55 ug/mL) and fibrinogen (FIB) (5.6g/L). Creatine kinase-MB (CKMB) and hsTNI levels were normal. His oxygen saturation (SPO2) was 89%-91% for room air and 96% on high-flow nasal cannula oxygen therapy (HFNC). He was unable to undergo revascularisation surgery to salvage the right lower limb. He was scheduled for right thigh amputation surgery following IVCF implantation (Figs. 2C-2E ). At day 1, he received anticoagulation (enoxaparin, 4000U, s.c), an antibiotic and supportive therapies.
At day 2, this patient was scheduled for implantation of a retrievable Cook Celect IVCF (William Cook, Europe) for preventing acute pulmonary embolism (PE) during the amputation surgery. The intervention was performed with bedside US on the isolation ward. This confirmed patency of the inferior vena cava, left iliac vein, and femoral vein. It also assured that percutaneous US guided IVCF implantation is feasible (Fig. 2C ). After local anesthesia and successful Seldinger puncture of the left femoral vein, the filter sheath was visually inserted into the left femoral vein through one 6Fguide sheath. Next, we injected 10 mL diluted SonoVue US contrast agent (Bracco, Milan, Italy) through the filter sheath to adjust the catheter tip location. The tip of the filter sheath was anchored 1cm below the right renal vein (Fig. 2D ). The filter was delivered into the catheter and deployed according to the manufacturer’s recommendations (Fig. 2E ). IVCF was deployed successfully. The patient was transferred to a disinfected theatre and proceeded with right thigh amputation surgery. Post-operatively, he was transferred to the isolated intensive care unit (ICU). Severe bilateral pneumonia was confirmed on a bedside chest X-ray on day 3 (Fig. 2F ). The IVCF position remained unchanged (Fig. 2F ). His D-dimer had progressively decreased from the initial value of 6.55 μg/mL to 2.85 μg/mL at day 7 after continuous anticoagulation therapy (enoxaparin, 4000U, s.c, q12 h). At day 9, he suffered an acute cardiac event with elevated hsTNI (10025.40 ng/L). He was treated medically for acute coronary syndrome. Supportive management was also optimised. A chest X-ray again confirmed severe bilateral pneumonia with no shit in the IVCF. At day 10, the creatine kinase-MB (CKMB) (262.70 ng/mL) and hsTNI (>50000.00 ng/L) levels kept increasing despite aggressive medical therapy. The patient eventually passed away on day 11 (Table 2 ).