Saddle Shaped Pulmonary Embolism – Saddle Pulmonary Embolism

Pulmonary embolism is a clinical, sometimes potentially life-threatening condition in which a circulating blood clot (i.e., medically known as a thrombus) obstructs one or more of the minor pulmonary arteries or the main pulmonary artery in case of large thrombi, causing a condition medically known as massive pulmonary embolism. It leads to an acute respiratory failure and hemodynamic compromise, which is a severe consequence that needs urgent hospital admission in an intensive care unit for medical care and intervention.


What is a saddle pulmonary embolism?

Saddle pulmonary embolism

Saddle Shaped pulmonary embolism is a type of thrombo-embolism that is large and obstructs the main pulmonary trunk and extends into its bifurcation. It is not an uncommon type of thromboembolism and requires urgent intervention to rescue the patient’s life. As a large thrombus, saddle pulmonary embolism causes hemodynamic instability and may lead to obstructive shock. It is also recognized as an aggressive form of pulmonary embolism and requires urgent treatment to solve the obstruction and deliver deoxygenated blood from right side of the heart (i.e. coming back from different body tissues) to the lung. This blood is meant to be oxygenated and pumped by the left ventricle through the aorta back to the tissues in order to supply them with oxygen.


Saddle pulmonary embolism symptoms

Similar to other types of pulmonary embolism, saddle pulmonary embolisms present with the same symptoms and signs. The most common signs are confined to dyspnea, tachypnoea, pleuritic chest pain, and palpitation. Hypoxemia and hypotension are also not uncommon due to the large obstructing nature of the embolus. These symptoms appear to be general and lack specificity, which means there’s a high risk of missing or diagnosing the disease too late. A high suspicion based on clinical findings and following diagnostic approaches will improve the diagnosis and prognosis. Early diagnosis and the early initiation of targeted treatment is associated with better prognosis.


Saddle pulmonary embolism diagnosis

Diagnosis of saddle pulmonary embolism is similar to other forms of pulmonary thrombo-embolisms. Clinical diagnosis is the main factor for risk stratification. Imaging studies as CT pulmonary angiography (now considered as the gold standard), Magnetic resonance imaging, V/Q scanning (ventilation/perfusion) and Echocardiography have a limited role in diagnosis, but may be used as screening tool. An invasive technique known as catheter pulmonary angiography which was the gold standard in the past, but has been stepped down due to its invasive nature.


Saddle pulmonary embolism treatment

Saddle pulmonary embolism needs urgent treatment and thrombolytic therapy to prevent the shock state and hemodynamic collapse associated with a large saddle thrombus. Treatment is divided into two phases: initial emergency treatment addressed to as acute-phase treatment, and a second phase or long-term management, which target secondary prevention and prophylaxis against recurrence.

The first step is to assess the need for thrombolytic therapy or surgical embolectomy in cases of thrombolysis contraindication or failed thrombolysis. Parenteral anticoagulation is the mainstay part of the acute phase treatment. The most commonly used parenteral agents are Heparin, Low molecular weight heparin, Fondaparinux, and Dalteparin. Some of these drugs could be used subcutaneous, and others are intravenous. This is followed by the start of long-term therapy using oral anticoagulants like warfarin (vitamin k antagonist) and Novel oral anticoagulants (NOACs) which have now gained FDA approval for long-term secondary prophylaxis of deep vein thrombosis and pulmonary thromboembolism.


 

Saddle pulmonary thrombo-embolism prognosis is strictly dependent on the appropriate diagnosis and the fast initiation of the suitable treatment plan tailored for each case and according to the presenting condition of the patient. It is also dependent on the long-term management and drug adherence to the oral anticoagulation.