Addition of Impella on top of venoarterial extracorporeal membrane oxygenation (VA-ECMO) has gained wide interest as it might portend improved outcomes in patients with cardiogenic shock. This has been consistently reported in retrospective propensity-matched studies, case series, and meta-analyses. The pathophysiologic background is based on the mitigation of ECMO-related side effects and the additive benefit of myocardial unloading. In this perspective, thorough knowledge of these mechanisms is required to optimize the management of mechanical circulatory support with this approach and introduce best practices, as the interplay between the two devices and the implantation-explantation strategies are key for success.

Extracorporeal membrane oxygenation (ECMO) in the veno-arterial (VA) configuration is an established method for the treatment of refractory cardiogenic shock. Such a condition characterizes the postoperative course of approximatively 1% of cardiac surgery patients. Although some studies have reported ECMO-related short-term results, little is known about the long-term outcomes of VA-ECMO therapy in the post-cardiotomy setting. Therefore, an extensive literature search was conducted regarding articles published after 1990 reporting postoperative ECMO use. PubMed, EMBASE and Web of Science were searched for sources. In-hospital mortality was high in post-cardiotomy VA-ECMO patients, ranging from 24.8% to 52%. Long-term results were poorly reported. However, based on the limited information available, hospital survivors showed a favorable outcome, with improvement in overall clinical condition, quality of life and limited hospital readmission for cardiac-related events. To conclude, in-hospital outcome in post-cardiotomy ECMO is often unfavorable, post-discharge results show satisfactory condition, with stable improvement of overall patient clinical status and low rate of hospital readmission and cardiac-related adverse events. Data reporting is, however, scarce and hence new and detailed studies are still warranted to investigate such aspects.

Veno-arterial extracorporeal membrane oxygenation (V-A ECMO) has been used to deal with life-threatening complications as well as back-up or active cardiovascular support during high-risk procedures in patients undergoing transcatheter aortic valve implantation (TAVI). PubMed and MEDLINE electronic databases were searched in order to identify studies with emergency or prophylactic V-A ECMO application in association with TAVI procedures. From November 2012 to November 2017, 14 relevant studies were identified that included 5,115 TAVI patients of whom 102 (2%) required V-A ECMO (22 prophylactically, 66 as an emergency and 14 without a reported indication). The reason for emergency V-A ECMO institution was detailed in 64 patients: left ventricle free wall rupture (n = 14), haemodynamic instability (n = 12), ventricular arrhythmias (n = 7), aortic annulus rupture (n = 6), coronary obstruction (n = 6), low left ventricular output (ejection fraction <35%) (n = 5), uncontrollable bleeding (n = 5), severe aortic regurgitation (n = 4), prosthesis embolisation (n = 3), aortic dissection (n = 1) and respiratory failure (n = 1). Femoral arterial and vein cannulation was the most common access technique for V-A ECMO institution. Major bleeding (n = 7) and vascular access complications (n = 7) were reported after ECMO institution. The overall in-hospital survival was 73% (61% in the emergency vs. 100% in the prophylactic group). V-A ECMO support should be available at any centre performing TAVI and provides effective mechanical circulatory support in an emergency setting. We present an algorithm to aid decisions about prophylactic circulatory assistance with V-A ECMO and it should form part of the heart team discussion before a TAVI procedure is undertaken.

Background: Left ventricular (LV) afterload increase with protracted aortic valve (AV) closure may represent a complication of veno-arterial extracorporeal membrane oxygenation (V-A ECMO). The aim of the present study was to assess the effects of an intra-aortic balloon pump (IABP) to overcome such a hemodynamic shortcoming in patients submitted to peripheral V-A ECMO. Methods: Among 184 adult patients who were treated with peripheral V-A ECMO support at Medical University Center Maastricht Hospital between 2007 and 2018, patients submitted to IABP implant for protracted AV closure after V-A ECMO implant were retrospectively identified. All clinical and hemodynamic data, including echocardiographic monitoring, were collected and analyzed. Results: During the study period, 10 subjects (mean age 60 years old, 80% males) underwent IABP implant after peripheral V-A ECMO positioning due to the diagnosis of protracted AV closure and inefficient LV unloading as assessed by echocardiography and an absence of pulsation in the arterial pressure wave. Recovery of blood pressure pulsatility and enhanced LV unloading were observed in 8 patients after IABP placement, with no significant differences in the main hemodynamic parameters, inotropic therapy or in the ECMO flow (p=0.48). The weaning rate in this patient subgroup (mean ECMO duration 8 days), however, was only 10%, with another patient finally transplanted, leading to a 20% survival-to-hospital discharge. Conclusion: IABP placement was an effective solution in order to reverse the protracted AV closure and impaired LV unloading observed during peripheral V-A ECMO support. However, the impact on the weaning rate and survival needs further investigations.

The peripheral veno-arterial extracorporeal life support (V-A ECLS) in cardiogenic shock (CS) may lead to LV overload. The trans-aortic suction device (Impella, ABIOMED Inc., Danvers, Massachusets) was compared to the pulmonary artery (PA) drainage, for LV unloading efficacy during V-A ECLS in a porcine cardiogenic shock model. A dedicated CS model included twelve swine (21± 1.8-weeks old and weighing 54.3 ± 4.6 kg) supported with V-A ECLS and randomized to Impella or PA-related LV drainage. LV unloading and end-organ perfusion were evaluated through the pulmonary artery catheter and LV pressure/volume analysis. The LV end diastolic volume sharply dropped with Impella (143.6±67.4 vs 123±75.7 ml) compared to a slight decrease in the PA cannula group (134.1±39.9 vs 130.1±34.7 ml), resulting in an overall stroke work (SW) and Pressure-Volume Area (PVA) reductions with both techniques. However, SW reduction was more significant in the Impella group (V-A ECLS 3998.8±2027.6 vs V-A ECLS + Impella 1796.9±1033.9 mmHg x ml, p=0.016), leading to a more consistent PVA reduction (Impella reduction 34.7% vs PA cannula reduction 9.7%) In terms of end organ perfusion, central and mixed O₂ saturation improved with V-A ECLS, and subsequently, remaining unchanged with either Impella or PA cannula as unloading strategy (SVmO2: Impella 86.0±5.8 vs 87.8±5.8; PA cannula 82.5±10.7 vs 82.5±11.3 %). Trans-aortic suction and PA drainage provided effective LV unloading during V-A ECLS while maintaining adequate end-organ perfusion. Impella provides a greater LV unloading effect and reduces more effectively the total LV stroke work.

Limb ischaemia is a clinically relevant complication of venoarterial extracorporeal membrane oxygenation (VA ECMO) with femoral artery cannulation. No selective distal perfusion or other advanced techniques were used in the past to maintain adequate distal limb perfusion. A more recent trend is the shift from the reactive or emergency management to the pro-active or prophylactic placement of a distal perfusion cannula to avoid or reduce limb ischaemia-related complications. Multiple alternative cannulation techniques to the distal perfusion cannula have been developed to maintain distal limb perfusion, including end-to-side grafting, external or endovascular femoro-femoral bypass, retrograde limb perfusion (e.g., via the posterior tibial, dorsalis pedis or anterior tibial artery), and, more recently, use of a bidirectional cannula. Venous congestion has also been recognized as a potential contributing factor to limb ischaemia development and specific techniques have been described with facilitated venous drainage or bilateral cannulation being the most recent, to reduce or avoid venous stasis as a contributor to impaired limb perfusion. Advances in monitoring techniques, such as near-infrared spectroscopy and duplex ultrasound analysis, have been applied to improve decision-making regarding both the monitoring and management of limb ischaemia. This narrative review describes the evolution of techniques used for distal limb perfusion during peripheral VA ECMO.