Catheter-Directed Thrombolysis for Pulmonary Embolism: The State of Practice

Acute pulmonary embolism (PE) is a major public health problem. It is the third most common cause of death in hospitalized patients. In the United States, there are up to 600,000 cases diagnosed per year with 100,000-180,000 acute PE-related deaths. Common risk factors include underlying genetic conditions, acquired conditions, and acquired hypercoagulable states. Acute PE increases the pulmonary vascular resistance and the load on the right ventricle (RV). Increased RV loading causes compensatory RV dilation, impaired contractility, tachycardia, and sympathetic activation. RV dilation and increased intramural pressure decrease diastolic coronary blood flow, leading to RV ischemia and myocardial necrosis. Ultimately, insufficient cardiac output from the RV causes left ventricular under-filling which results in systemic hypotension and cardiovascular collapse. Current prognostic stratification strategy separates acute PE into massive, submassive, and low-risk by presence or absence of sustained hypotension, RV dysfunction, and myocardial necrosis. Massive, submassive, and low-risk acute PE have mortality rates of 25%-65%, 3%, and <1%, respectively. Current PE management includes the use of anticoagulation alone, systemic thrombolysis, catheter-directed thrombolysis, and surgical embolectomy. This article will describe the current state of practice for catheter-directed thrombolysis and its role in the management of acute PE.