**5. Diagnosis**

The diagnosis of PE in COVID-19 patients is challenging as signs and symptoms of PE are not specific and overlap with COVID-19 respiratory manifestations.

Hence PE is diagnosis is often missed or delayed in COVID-19 patients. As COVID-19 patients may be unstable and have high risk of viral aerosolization, imaging studies may not be practically possible. Initial diagnosis is suspected based upon the physical, clinical and laboratory parameters. If COVID-19 patients have DVT (deep venous thrombosis) patients will have moderate to high chances of developing PE.

Unexplained tachycardia, tachypnea or dyspnea, poor gas exchange or hemodynamic instability and sudden worsening respiratory status should ring an alarm of possible PE diagnosis. Patients with risk factors such as malignancy, on hormonal therapy, having milder x-ray changes, not correlating to or out of proportion to clinical severity of the disease should give high index of suspicion of PE. A study shows that only 33% of COVID-19 patients with PE had a Wells' score of more than 4, hence Wells' score has limited application in COVID-19 patients [13].

ECG (electrocardiography) often shows tachycardia; however, it may reveal right heart strain pattern in severe cases. The point of care echocardiography

### **Figure 1.**

(POCUS) may show acute right ventricular overload and dilatation, intra-cardiac thrombi, or thrombus transit.

Rapid increase in inflammatory markers and D-dimer levels is commonly associated with the development of PE in COVID-19 patients. Elevated D-dimers were found to be associated with a 50% increased risk of DVT in COVID-19 patients [14]. As these inflammatory markers and D-dimers also elevated in primary or secondary infection, hence recent guidelines advise against using them as association of PE or DVT [15]. Normal D-dimer levels on the contrary are sufficient to rule out DVT or PE with confidence [15].

CTPA (computerized tomographic pulmonary angiography) is specific and sensitive imaging modality to diagnose, confirm or exclude PE. CTPA has an accuracy of 95% in the diagnosis of the PE, and in its absence, gives alternative diagnosis. All infection control precautions, and hemodynamic monitoring should be continued while transporting patients to the imaging suite. **Figure 1** reflects steps wise algorithm for the diagnosis of PE in COVID-19 patients.

### **6. Management**

Therapeutic anticoagulation is the key in the management of PE in COVID-19 patients. Thromboprophylaxis should be started in all patients diagnosed with COVID-19 infection. Selection of anticoagulation medication depends on presence of comorbidities, organ dysfunction or failure. Especial consideration is required in renal, liver, gastrointestinal dysfunction, and thrombocytopenia.

The recommended first line anticoagulants are the LMWH (low molecular weight heparin) due to their obvious benefits, but unfractionated heparin (UFH) is the drug of choice in patients with severe renal impairment, patients expecting surgical intervention or invasive procedures. The reason is that unfractionated heparin has a shorter half-life and is easy to reverse with protamine sulfate. All these

### *Pulmonary Embolism in COVID-19 Patients: Facts and Figures DOI: http://dx.doi.org/10.5772/intechopen.99942*

patients should have regular monitoring of coagulation parameters and the dose should be titrated accordingly [9].

Direct oral anticoagulants (DOAC) should be avoided in acute phase as the patients' organ dysfunction can potentiate and prolong the DOAC action. Their reversal is not easily available as well. DOAC can be considered in the recovery phase of COVID-19 as they have advantage of not requiring monitoring of coagulation parameters [9].

The use of catheter guided therapies should be limited to the most critical patients in the COVID-19 pandemic [9, 15].

Insertion of inferior vena cava (IVC) filter should be considered in patients with recurrent PE and/or DVT despite optimal anticoagulation or having absolute contraindication for anticoagulation [9]. Thrombolytic therapy is immediate choice if the patient is hemodynamically unstable and/or echocardiogram is showing right heart dilatation or pulmonary hypertension.

**Figure 2.** *Management of pulmonary embolism in COVID-19 patients.*

In patients with refractory hypoxia or shock or cardiac arrest, ECMO (extracorporeal membrane oxygenation) therapy alone or in combination with thrombectomy or catheter guided thrombolysis is the recommended therapy [9].

All hospitalized COVID-19 patients and patients admitted to ICU should be on thromboprohylaxis, and these patients with increase in inflammatory markers (CRP and Platelets) and D-dimer levels more than 3 ug/ml should be therapeutic dosage of LMWH or UFH depending on their organ dysfunction particularly renal functions [9].

PE managed by PERT (pulmonary embolism response team) may lead to better patient outcomes. PERT not only expedites the diagnosis, but also provides coordinated, multidisciplinary care to PE patients. PERT usually varies in different hospitals and may include an intensivist, cardiothoracic and vascular surgeons, emergency medicine specialist, interventional radiologist, and a clinical pharmacist [16]. PE in COVID-19 patients can be better managed by using an algorithm of care (**Figure 2**).

### **7. Morbidity and mortality**

COVID-19 patients who have PE usually have longer durations of mechanical ventilation, ICU and hospital stay [17]. They have a 45% higher mortality compared to those without PE. Mortality in COVID-19 patients with PE depends on comorbidities, organ dysfunction and length of hospital stay [17]. The mortality is significantly high is first week especially in patients with increased inflammatory markers and may be related to the severity of the disease [17].

### **8. Conclusion**

The risk of PE is quite high in COVID-19 patients. Severe disease requiring hospitalization, ICU admission, obesity, history of atrial fibrillation, cancer and convalescent plasma therapy increases the risk of PE in COVID-19 patients. Endothelial injury in COVID-19 patients occurring due to viral penetration and load causes loss of vasodilatory, anti-adhesive properties and fibrinolysis. It also stimulates the release of cytokines and von Willebrand factor leading to micro thrombi formation in small and medium sized blood vessels.

Diagnosis of PE requires high index of suspicion in COVID-19 patients. Normal D-dimer levels exclude PE with confidence. Bedside transthoracic echocardiography may show right heart dilatation, thrombus in the heart or pulmonary arteries. CTPA is highly sensitive and specific in the diagnosis of PE. If PE is absent CTPA may also give an alternate diagnosis.

Anticoagulation with LMWH and UFH is essential part of the PE management. Few patients may need catheter guided thrombolysis, thrombectomy and/or ECMO therapy.

COVID-19 patients complicated with PE have higher number of days with ventilatory support, ICU and hospital stay. Occurrence of PE in COVID-19 patients also increases the mortality.

*Pulmonary Embolism in COVID-19 Patients: Facts and Figures DOI: http://dx.doi.org/10.5772/intechopen.99942*

## **Author details**

Nissar Shaikh1 \*, Narges Quyyum1 , Arshad Chanda1 , Muhammad Zubair1 , Muhsen Shaheen2 , Shajahan Idayatulla1 , Sumayya Aboobacker1 , Jazib Hassan1 , Shoaib Nawaz1 , Ashish Kumar1 , M.M. Nainthramveetil1 , Zubair Shahid3 and Ibrahim Rasheed4


\*Address all correspondence to: nissatfirdous99@gmail.com

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
