Written by Nick Zelt
This is a scientific statement from the American Heart Association (AHA) emphasizing the need for more research on surgical embolectomy (SE) and mechanical circulatory support (MCS) in the treatment of high-risk pulmonary embolism (PE).
Why does this matter?
PE is common. The lifetime risk of PE after the age of 45 is 8.1%. Additionally, an estimated 45% of PEs will progress to more severe clinical presentations, which may include hemodynamic instability due to right heart failure. PE is the third leading cause of cardiovascular death in the U.S. Per AHA and European Society of Cardiology (ESC) guidelines, thrombolytic and transcatheter therapies are recommended as initial measures, while SE and MSC are reserved for more critically ill patients or those with contraindications to the former. The AHA has released a statement on the use of these interventions.
Bridge to better options…remove the clot and fix the problem…or both?
This statement focuses on high-risk patients with acute PE. Use of SE and MCS are not mutually exclusive. The authors acknowledge that historically, MCS and SE have been used, almost exclusively, only in the most high-risk patients.
SE dates back to the early 1900s, decades before heparin was used clinically. Development of a cardiopulmonary bypass machine was imperative for the success of these procedures. Current guidelines recommend SE as a last resort after failing or being excluded from standard treatments. Despite a disproportionately high-risk population (preoperative CPR in 4.9%-45.8%), in-hospital mortality for patients undergoing SE has improved dramatically to now be 2.3%-13.2%, with mortality largely associated with the CPR subgroup. Currently, exact indications to refer for SE are not well defined.
In addition to enabling safe SE, MCS is an alternative treatment to temporarily offload the right ventricle (RV) and buy time for catheter-directed lysis or SE. The diversion of venous flow in VA-ECMO decompresses the failing RV. VV-ECMO, while fixing the oxygenation/ventilation abnormalities of high-risk PE, does not treat RV overload. For some perspective, VA-ECMO for PE-arrest has shown markedly higher survival rates when compared to those for acute MI (70% vs. 17%, respectively).
The authors close with a call for more high-risk PE registries and trials, a refined definition of ‘high-risk PE’ (i.e. a drop in systolic by 40 mmHg is quite different than cardiac arrest), optimization of metrics to assess the efficacy of SE and MCS (i.e. RV recovery vs mortality), and improved awareness and education about these interventions.
Surgical Management and Mechanical Circulatory Support in High-Risk Pulmonary Embolisms: Historical Context, Current Status, and Future Directions: A Scientific Statement From the American Heart Association. Circulation. 2023;10.1161/CIR.0000000000001117. doi:10.1161/CIR.0000000000001117
Peer reviewed by Bo Stubblefield