Infection with SARS-COV-2 generates alterations in coagulation factors, mainly elevation of D-dimer values. These coagulation disorders jointly with activation of inflammatory factors trigger thrombotic events such as pulmonary embolism.1 Although, presence of free floating right heart thrombus is unusual situation in patients with massive pulmonary embolism.
A 56-year-old caucasian male with morbid obesity (BMI 45kg/m2), with 15-day history of dyspnea, myalgia and dry cough, was admitted to emergency room. First rapid SARS-CoV-2 PCR was negative, but with high clinical suspicion, pharmacological treatment was started. Tachypnea and dry crackles were observed at physical examination. Laboratories studies showed white-cell count 15.80×109/L (12% lymphocytes), lactate dehydrogenase 425 UI/L, C-reactive protein 3.82mg/dl and D-dimer 32,000mcg/L. Arterial blood gas PaO2 55mmHg at room air. CT pulmonary angiography (CTPA) could not be performed due to patient's anthropometry. According to high probability of pulmonary embolism (PE), a transthoracic echocardiogram was practiced, revealing multiple thrombus at the right atrium and right ventricle, severe dilatation of the right cavities with signs of overload right ventricle and significant PAH (pulmonary arterial pressure 110mmHg). Low molecular weight heparin was initiated. Despite negative PCR results, up to three SARS-CoV-2 PCR kept negative results. After a significant weight loss, CTPA could be performed showing filling defects in the main pulmonary artery consistent with pulmonary embolism and ground-glass areas in both upper lobes and left lower lobe. Patient rest instable with severe respiratory failure, subsequently thrombolysis with reteplase was performed with good outcomes. Echocardiogram after procedure showed the absence of intracardiac thrombus and reduced PAH (60mmHg). Even though having three negative rapid SARS-CoV-2 PCR, 10 days later, serologies showed positive results for IgG (Elisa technique), which confirmed Covid-19 pulmonary affection diagnosis.
SARS-COV-2 infection generates coagulation disorders with elevated D-dimer values, due to systemic pro-inflammatory cytokine to activate procoagulant factors, which predispose to thromboembolic events like PE.2
Obesity (BMI>35kg/m2) is widely reported as a risk factor for thromboembolic disease (especially pulmonary embolism and deep venous thrombosis). Thromboembolic mechanisms generated in morbid obesity include increased platelet activity, procoagulant states, altered fibrinolysis, and endothelial cell activation.3
Dyspnea, as a prevailing symptom of COVID19 pneumonia, makes clinical recognition of PE quite challenging, therefore diagnostics tests are needed for rapid management, and imaging techniques such CT pulmonary angiography are conveniently. In patients with PE, the existence of intracardiac thrombosis in right cardiac cavities is unusual unless atrial fibrillation is set, occurring between 4 and 18% in cases of massive PE. Combination of massive PE an intracardiac thrombosis it's a medical emergency with increased mortality, which requires an urgent treatment. Thrombolysis is usually the best choice due to the double target of the therapy, the PE and the cardiac thrombus.4
The diagnostic challenge that arises is that, even with the clinical suspicion of COVID19 infection, with acute respiratory failure and massive PE with intracardiac thrombosis, needing urgent diagnosis and treatment, plus a negative result of a PCR test cannot stop the attitude and management to follow up. The Real-Time reverse-transcriptase polymerase chain reaction (RT-PCR) can present false negatives due to the low viral charge obtained in the sample, requiring the detection of antibodies for the diagnostic. Jin et al. show a sensitivity higher than 90% in IgM and IgG test compared to molecular detection, after 5 days since the realization of serological tests.5
In conclusion, although obesity is an independent risk factor for thromboembolic events, other factors must be considered, especially coagulation disorders caused by COVID19 infection. Then, the presence of negative PCR for SARS-COV-2 healthcare providers should not neglect the disease, so a subsequent serological study may confirm the diagnosis.
Conflicts of interestAuthors declare no conflicts of interest.
