A pulmonary embolism (PE) is a serious medical event where a blood clot travels to the lungs, obstructing blood flow. Among the various types, a saddle pulmonary embolism stands out due to its specific location and size. This large clot “saddles” or becomes lodged at the bifurcation of the main pulmonary artery, where it divides to supply blood to both the left and right lungs. The critical nature of a saddle PE arises from its ability to significantly impede blood flow to both lungs simultaneously, placing immediate and severe strain on the heart.
What is a Saddle Pulmonary Embolism?
A saddle pulmonary embolism is a distinct and particularly concerning type of PE. This large clot is positioned precisely where the main pulmonary artery branches into the arteries leading to each lung, effectively blocking blood flow to both.
This unique anatomical location makes a saddle PE especially dangerous, as the obstruction prevents deoxygenated blood from the heart from reaching the lungs for oxygenation. This significant blockage can cause blood pressure to drop, leading to inadequate blood supply throughout the body and potentially damaging vital organs. While saddle PEs are rare, accounting for about 2.6% to 5.4% of all acute PE cases, their size and location pose an immediate threat to cardiovascular stability.
The Survival Rate
The survival rate for a saddle pulmonary embolism has improved due to advances in medical care. Historically, this PE type carried a high mortality risk due to extensive blockage. However, better diagnostic methods and treatment strategies have led to improved outcomes.
Recent studies indicate varying mortality rates. A 2021 study observed an in-hospital mortality rate of 9.2% among 120 patients with saddle PE, with an additional 8.6% dying within six months of discharge. A 2014 study found the in-hospital mortality rate for saddle PE to be around 3.62%, similar to other PE types. About one in four people who develop any form of pulmonary embolism may die instantly, with another 10-30% dying within a month of diagnosis.
Factors Impacting Survival
Several factors influence survival from a saddle pulmonary embolism. A patient’s overall health is important, as pre-existing conditions like heart disease, lung disease, or cancer can complicate the prognosis. Older age and general frailty also contribute to a less favorable outlook.
Hemodynamic stability at presentation is a major determinant. Patients experiencing shock or low blood pressure upon hospital arrival face a higher immediate risk. Prompt diagnosis and treatment are crucial, as early detection and urgent medical care reduce fatality. The exact degree of obstruction and access to specialized medical care, including advanced diagnostic tools and interventional treatments, also impact survival.
Immediate Care and Outlook
Immediate medical intervention is crucial for individuals diagnosed with a saddle pulmonary embolism. Diagnosis often involves a CT scan of the pulmonary arteries, the primary tool to visualize the clot’s exact location and size. Initial care focuses on stabilizing the patient’s condition, supporting blood pressure, and ensuring adequate oxygenation.
Treatment aims to dissolve or remove the clot and prevent new ones. This typically involves blood thinners (anticoagulants) to stop clot growth. For severe cases, thrombolytics (“clot-busting” medications) may rapidly dissolve the obstruction, despite a higher bleeding risk. If medications are ineffective or contraindicated, surgical embolectomy or catheter-directed interventions may be considered. If a patient survives the initial critical period, the immediate outlook generally improves, though ongoing monitoring is necessary.