Catheter-assisted pulmonary embolectomy.

Case presentation: A 65-year-old man presented to the emergency department after a fall and was diagnosed with a fracture of the right femoral neck. He was scheduled for surgical repair the following day. During positioning for arthroplasty, he developed hypotension, tachycardia, and hypoxia, followed by pulseless electric activity. He was resuscitated and maintained on epinephrine and norepinephrine infusions. A transesophageal echocardiogram revealed a dilated and hypokinetic right ventricle with preserved apical contractility (Figure 1). Massive pulmonary embolism (PE) was suspected. What are the therapeutic options for this critically ill patient? Patients afflicted with massive PE have 90-day mortality rates approaching 50%.1 Massive PE is defined by sustained hypotension (systolic blood pressure 90 mm Hg for a minimum of 15 minutes, or requirement for inotropic support), pulselessness, or bradycardia with signs of shock.2 As many as 10% of patients with submassive PE can develop hemodynamically significant and life-threatening right ventricular failure.3 In such cases, supportive care and anticoagulation must be accompanied by rapid reduction of right ventricular (RV) afterload and restoration of adequate cardiac output. Many patients with submassive PE and stable blood pressure develop residual RV dysfunction and experience a decline in functional status at 6-month follow-up. Acute relief of RV strain and reduction of thrombotic burden in the pulmonary arteries could yield long-term benefit in this group.4 Pharmacological and invasive strategies for reduction of thrombotic burden in the pulmonary arteries have been used for many decades with variable success. Systemic intravenous thrombolysis has been shown to be of benefit in small trials of patients with massive PE, but it failed to reduce short-term mortality and morbidity in a wide range of patients with submassive PE.5 Thrombolytic therapy is widely available and easy to administer, but these attributes are offset by the obligatory 2-hour infusion, a costly delay when immediate effect is required. Contraindications to systemic thrombolysis are present in as many as 50% of patients,6 and major bleeding complications can occur in 20% of patients,5 further limiting the utility of this therapy. Surgical embolectomy, first conceived by Trendelenburg in 1908 and performed by Kirschner in 1924,7 can be life saving in patients with clot burden in the proximal pulmonary artery (PA). Advances in surgical and anesthesiology techniques have reduced perioperative mortality to 20%,8 but the best outcomes are achieved in a few selected centers with dedicated, rapid-response embolectomy programs. Percutaneous strategies for treatment of massive and submassive PE date back to the development of the Greenfield suction catheter in the 1960s.9 Technical advances in endovascular devices now allow for combining mechanical thrombus disruption and aspiration with pharmacological thrombolysis. This is called pharmacomechanical therapy. Pharmacological therapy allows rapid reduction in RV afterload in patients with hemodynamic instability, whereas mechanical therapy reduces thrombus burden via longer, catheter-directed infusion of a low-dose thrombolytic. There is a growing interest in clinical applications and large-scale investigations of these pharmacomechanical therapies in patients with massive PE and selected patients with submassive PE. This Clinician Update will examine the rationale for catheter-based pulmonary embolectomy and describe endovascular techniques commonly used today.