**4. ECMO for high-risk procedures**

The introduction of VA-ECMO as cardiopulmonary support has paved the way for new operative indications for those patients who were previously relegated to conservative medical management. Patients with poor left ventricular function, CS with complex multivessel disease, or multiple other comorbidities now could be undergone revascularization with circulatory support of ECMO. Recent applications have shown ECMO to be potentially effective as a temporizing measure or bridge to therapeutic intervention in the setting of myocardial dysfunction and CS. Extracorporeal life support is now used in many more difficult situations due to recent advances in knowledge and familiarity. These include a number of high-risk catheter-based procedures, such as transcatheter aortic valve implantation (TAVI) and percutaneous coronary interventions (PCI) [13–15], post-infarct ventricular septal defect (PI-VSD) repair as well as surgery on the thoracoabdominal aorta, international retrievals for cardiac and respiratory failure [16], and in case of massive pulmonary thromboembolism as a bridge for embolectomy (PTE) [17].

## **4.1 ECMO support in high-risk percutaneous coronary intervention (HR-PCI)**

Early reports of total cardiopulmonary support or cardiopulmonary bypass (CPB) during high-risk PCI were aimed at understanding the best time to initiate support, either prophylactically or to be on "standby" during the procedure. Prophylactic vs standby percutaneous CPB in HR-PCI was compared in a retrospective data analysis of 23 national registries with 569 patients. 180 patients were in the standby group and 389 patients were in the prophylactic CPB group. The procedural success rate was almost the same in both groups (88.7 % compared to 84.4 %); however, the periprocedural mortality rate was greater in the standby group (18.8 % versus 4.8 %, p = 0.05) [18]. Subsequent studies showed more evidence for the benefit of ECMO use in a patient with ST-segment elevation myocardial infarction (STEMI) complicated by CS unresponsive to inotropes and intra-aortic balloon pump (IABP) [19, 20].
