High-grade or acute mitral regurgitation (AMR) is difficult to treat and the medical management of these cases has very poor outcomes with regard to survival. Ruptures are more common in the posterior medial than anterior lateral papillary muscle due to the single blood supply coming from the posterior descending artery. This can often be corrected by transcatheter edge-to-edge repair (TEER) surgery, which repairs the rupture to correct mitral valve function, but this is not always an option due to the severity of presentation and low surgical survival odds. AMR results in increased left ventricular (LV) and atrial volumes and pressures, decreased ejection fraction and pulmonary congestion, and the decreased systemic flow can result in cardiogenic shock (CS). The SHOCK trial, which examined direct invasive emergency revascularisation in patients with CS complicating acute MI, showed in-hospital mortality of 71% for AMR shock patients and 40% for surgical candidates.1 These mortality rates have remained steady since the publication of that study in 2000, demonstrating a clear unmet need for this population.2 Dr Verma and his team therefore asked whether mechanical circulatory support (MCS) with Impella, followed by repair of the mitral valve with MitraClip and TEER, can improve the survival of these patients.
Recent published case reports have revealed desirable haemodynamics (increased blood pressure and reduced left atrial pressure) for AMR patients who received MitraClip therapy, as well as improved forward systemic flow.3,4 In addition, these case reports revealed no evidence of patients with a low cardiac output state after Mitral clipping, which has been reported historically in patients who undergo surgery for AMR.5–7 These improvements observed with percutaneous repair by MitraClip have also resulted in reduced mortality risks at 1 year.8 Dr Verma and his team hypothesised that Impella can stabilise the patient, which, in turn, can improve the MitraClip surgical process and outcomes. In their study, there was a 100% technical success rate with implementation of the Impella and MitraClip, and all patients were successfully weaned from MCS support after implantation of MitraClip. Patients demonstrated continually improving haemodynamics over 30 days, with greatly reduced mitral regurgitation and steadily increasing LV ejection fraction.9 The haemodynamic improvements resulted in functional improvements, and Dr Verma and his team observed a survival rate of 86% at 30 days.
Dr Verma reviewed the work-up algorithm that his consortium uses for patient evaluation to determine whether this combined approach is appropriate for each patient’s presentation. Patients are initially treated with medication, maximum revascularisation and percutaneous MCS as appropriate, but, if severe mitral regurgitation is still suspected, patients are considered as candidates for TEER, and a heart team consult is obtained. Dr Verma concluded that although AMR is typically associated with significant haemodynamic compromise and poor outcomes, treating patients with Impella and MitraClip plus TEER can provide a survival advantage, and this approach therefore merits further study.