Use of Extracorporeal Membrane Oxygenation and Impella as Bridge to Surgery Through Imaging for Cardiogenic Shock.

Three-dimensional TEE, zoomed volume acquisition, oriented to the surgeon's view of the mitral valve. (A) The left atrial erspective demonstrates a flail A3 segment with a ruptured posteromedial papillary muscle (arrow). (B) Three-dimensional color Doppler demonstrates severe MR. (C, D) Three-dimensional transillumination; left atrial (left) and LV (right) perspective demonstrated. This technique was used to highlight the blood pool-tissue interface. The degree of transparency was adjusted to maximize the border definition between the ruptured posteromedial papillary muscle and blood pool and more clearly demonstrate the ruptured posteromedial papillary muscle (dashed arrow). 2022 by the American Society of Echocardiography. Published by Elsevier Inc.

Introduction

Left ventricular (LV) myocardial infarction complicated by papillary muscle rupture and resultant cardiogenic shock is associated with significant morbidity and mortality. We present a case to illustrate the use of extracorporeal membrane oxygenation (ECMO) and Impella (Abiomed) as bridge to surgery through transesophageal echocardiographic (TEE) imaging for cardiogenic shock due to acute severe mitral regurgitation (MR) resulting from a myocardial infarction–related ruptured papillary muscle.

Case Presentation

A 75-year-old man presented late with an inferior ST elevation myocardial infarction (STEMI) complicated by cardiac arrest and cardiogenic shock. Following return of spontaneous circulation, bedside point-of-care ultrasound revealed LV inferior wall akinesis and MR with suspected papillary muscle rupture. Diagnostic coronary angiography revealed significant three-vessel coronary artery disease. Transesophageal echocardiography confirmed a ruptured posteromedial papillary muscle with severe MR (Figures 1 and 2; Videos 1-5), with a proximal isovelocity surface area radius of 1.1 cm (aliasing velocity = 0.6 m/sec), effective regurgitant orifice area of 1.4 cm2, and regurgitant volume of 72 mL. There was LV dilation (end-systolic diameter = 4.5 cm), with mild-moderate systolic dysfunction (LV ejection fraction = 45%), mild right ventricular dilatation with moderate-severe systolic dysfunction, and mild left atrial dilatation.

Figure 1

Two-dimensional TEE mitral commissural view with biplane imaging showing the mitral valve, left ventricle, and left atrium in diastole (A) and systole (B). There is evidence of complete posteromedial papillary muscle rupture (arrows) (Video 1). With color Doppler (C) and pulsed-wave Doppler analysis of the systolic flow reversal in the pulmonary veins (D), severe MR (Video 2) is shown.

Figure 2

Three-dimensional TEE, zoomed volume acquisition, oriented to the surgeon's view of the mitral valve. (A) The left atrial erspective demonstrates a flail A3 segment with a ruptured posteromedial papillary muscle (arrow) (Video 3). (B) Three-dimensional color Doppler demonstrates severe MR (Video 4). (C, D) Three-dimensional transillumination; left atrial (left) and LV (right) perspective demonstrated. This technique was used to highlight the blood pool–tissue interface. The degree of transparency was adjusted to maximize the border definition between the ruptured posteromedial papillary muscle and blood pool and more clearly demonstrate the ruptured posteromedial papillary muscle (dashed arrow) (Video 5).

Staged surgical intervention was the chosen strategy over emergent surgery, as neurological status was uncertain following a prolonged period of cardiac arrest. Hemodynamic support with peripheral (femoral) venoarterial ECMO (VA-ECMO) was commenced within hours of hospital presentation, as a bridge to surgery. VA-ECMO was initially chosen over isolated left-sided mechanical support (Impella) given the presence of right ventricular systolic dysfunction.

With increasing ECMO flow, and subsequent increase in aortic pressure, LV volume increase, and reduction in stroke volume, with the last one being particularly reduced due to severe MR, LV stasis developed within 15 minutes of initiating VA-ECMO. Transesophageal echocardiography demonstrated minimal aortic valve leaflet opening and significant stasis of blood flow at the aortic root and ascending aorta, despite the administration of systemic therapeutic anticoagulation (Figure 3, Videos 6 and 7). Transient reduction in ECMO flow, and thus LV loading, resulted in improved aortic valve opening and reduction in stasis at the aortic root/ascending aorta; however, this was associated with hypotension and systemic hypoperfusion. In light of developing aortic stasis, an Impella device was placed (Figure 4), enabling LV unloading, antegrade flow support, aortic root washing, and resolution of the aortic stasis (Videos 8-10). The patient's hemodynamic status stabilized; serial echocardiography demonstrated stable LV end-diastolic dimensions indicating no worsening LV distension and no elevation in right ventricular systolic pressures. The patient subsequently underwent surgery 48 hours later.

Figure 3

Two-dimensional TEE midesophageal long-axis view with biplane imaging (A, D) following commencement of VA-ECMO, demonstrating minimal aortic valve opening and significant stasis of blood flow in the aortic root and ascending aorta (arrow) (Video 6). (B) Two-dimensional color Doppler demonstrates significant but reduced MR (Video 7). (C) Pulsed-wave Doppler demonstrates systolic flow reversal in the left upper pulmonary vein. (D) Temporary reduction in ECMO flow, and thus LV loading, resulted in improved aortic valve opening and reduction in stasis at the aortic root/ascending aorta.

Figure 4

Two-dimensional TEE midesophageal long-axis view with biplane imaging (A-C) following placement of an Impella device (arrow), demonstrating significant reduction in stasis of flow at the aortic root/ascending aorta (Video 8) (A) with no interaction of the ventricular component of the device with the mitral valve or subvalvular apparatus (Video 9) (B, systole; C, diastole). (D) Two-dimensional color Doppler demonstrates further reduction in MR (Video 10).

Discussion

Papillary muscle rupture is a rare but lethal complication of STEMI and is associated with a 65% risk of presenting as cardiogenic shock and often requires mechanical circulatory support device(s) for hemodynamic support. The goal of hemodynamic support in this setting is to reduce afterload and improve systemic blood pressure and blood flow to critical organs, while concurrently reducing LV end-diastolic pressure and pulmonary capillary wedge pressure (PCWP). VA-ECMO in the setting of acute severe MR may result in a rightward shift of the pressure-volume loop, increase in afterload, and subsequent rise in end-diastolic and end-systolic volumes and elevation in the PCWP., Echocardiography may be useful in identifying the importance of early LV unloading, through monitoring of Doppler-derived left heart pressures, worsening aortic or MR, or increasing right ventricular systolic pressures suggestive of rising PCWP from pulmonary edema and elevated LV filling pressures. Left ventricular distension is of concern following commencement of VA-ECMO, which may worsen in the setting of acute severe MR. Effective hemodynamic support in the setting of acute severe MR requires VA-ECMO with concurrent Impella support for afterload reduction. However, the degree of Impella support is less than what would be required if used as isolated LV support.

Conclusion

Clinicians should be aware of the risk of VA-ECMO-related significant aortic stasis, which may develop in the setting of increasing afterload and reduction in stroke volume, the latter particularly occurring in the situation of acute severe MR. Echocardiography may be used to identify the importance of implementing an LV unloading strategy to reduce afterload and provide more effective hemodynamic support in this clinical context.