Do Sheath Length and ECMO Availability Correlate with Adverse Events in Patients Undergoing Percutaneous Thrombectomy for Pulmonary Embolism?

Pulmonary embolism (PE) is currently the third leading cause of cardiovascular mortality. To avoid the hemorrhagic complications associated with catheter-directed thrombolysis, there has been an increase in the use of percutaneous aspiration thrombectomy (AT) devices for the treatment of patients with intermediate to high-risk pulmonary embolism (PE). A concern with large bore devices and sheath placement into the main pulmonary artery is possible effects on heart contractility and development of arrythmias. This study assessed the safety and effectiveness of different devices to treat PE.

Methods: This single-center retrospective chart review study included patients that underwent percutaneous interventions with AT (aspiration thrombectomy) or MT (mechanical thrombectomy) with or without adjunctive thrombolysis for treatment of pulmonary embolism from 2017 to 2023. Small bore devices (CAT 8) and large bore devices (CAT 12, FlowTriever and Lightning FLASH) were examined. The primary outcome was development of a new arrhythmia or hemodynamic collapse during the thrombectomy procedure. Secondary outcomes included single session success (no need for adjunctive thrombolysis), and mortality. Additional factors were analyzed including sheath length, and ECMO cannulation.  

Results: A total of 73 patients were treated with AT or MT. Average age was 58. Average RV/LV was 1.7 and average RVSP was 46. 67 were classified as intermediate-high risk, 6 were high risk. Long sheaths (65-80cm) were used in 55 patients, short sheaths (33cm) in 18 patients. The primary endpoint of new arrythmia or hemodynamic collapse occurred more often when longer sheaths were placed into the main pulmonary artery (n=6). The larger-bore devices were more effective at achieving single-session therapy (n=64, p< 0.05). There were 6 mortalities, all stratified as high risk. All 6 mortalities were noted before the ECMO service became available. Additionally, 4 patients were cannulated for ECMO after failing systemic thrombolysis. Three patients underwent successful AT following ECMO cannulation, all 3 patients survived. One patient that had been cannulated for ECMO died prior to thrombectomy.

Conclusions: Large bore thrombectomy devices offer a distinct advantage to patients affected with pulmonary embolism. This analysis confirms larger bore catheters are more effective at achieving single-session therapy. However, passing large bore devices/sheaths into the pulmonary artery may occasionally lead to arrythmias or hemodynamic collapse.  Perhaps there is an advantage to devices that allow for safe passage through the right heart while leaving the stiffer sheath in the vena cava. There also appears to be an advantage in institutions that offer ECMO availability.