Transcatheter edge-to-edge mitral repair with a nitinol device in cardiogenic shock on micro-axial flow-pump support: a case report

Abstract

Background

Severe functional mitral valve regurgitation due to acute myocardial infarction in the setting of profound cardiogenic shock presents a challenging treatment scenario. Persistent mitral regurgitation despite successful myocardial revascularization requires a careful and effective treatment approach.

Case summary

A 54-year-old male was admitted to our cardiac arrest centre due to severe cardiogenic shock. The patient underwent percutaneous coronary intervention with stenting of the left main coronary artery, left anterior descending, and ostial left circumflex artery in the setting of a ST-elevation myocardial infarction. After successful revascularization, cardiogenic shock persisted and advanced temporary mechanical circulatory support (tempMCS) with extracorporeal membrane oxygenation and a micro-axial flow pump was required. Further diagnostic evaluation revealed severe functional mitral regurgitation despite sufficient left-ventricular unloading. We present a case in which tempMCS stabilized the patient and mitral regurgitation was successfully eliminated using a transcatheter edge-to-edge repair flexible nitinol device.

Discussion

While mitral valve transcatheter edge-to-edge repair in cardiogenic shock on mechanical circulatory support is rare, it has shown feasibility and positive outcomes in limited reports. This is the first case using a nitinol edge-to-edge repair device in this context. Our report emphasizes the need for further discussion on device selection and comparative studies to optimize treatment in this high-risk group.

Learning points.

• Mitral transcatheter edge-to-edge repair (M-TEER) may be considered for acute functional mitral regurgitation in patients on temporary mechanical circulatory support when surgery is not feasible.

• Left ventricular geometry and extend of leaflet tethering should guide device selection for M-TEER in functional mitral regurgitation.

Introduction

Severe functional mitral regurgitation (MR) in the setting of myocardial infarction is associated with increased mortality and rehospitalization, particularly in patients with cardiogenic shock (CS).¹ Mitral transcatheter edge-to-edge repair (M-TEER) has been shown to be feasible in high-risk patients with suitable anatomy and reduced left ventricular ejection fraction (LVEF).² Isolated case reports and case series have demonstrated the feasibility and efficacy of M-TEER with the MitraClip (Abbott Cardiovascular, Plymouth, MN, USA) device in patients supported with temporary mechanical circulatory support (tempMCS).^3,4 This case illustrates the complexity of functional MR in CS following ST-elevation myocardial infarction (STEMI).

Summary figure

Summary figure illustrating the clinical course of the patient, including a structured clinical timeline from acute myocardial infarction and cardiogenic shock to mitral transcatheter edge-to-edge repair and follow-up.

Case presentation

A 54-year-old man was transferred to the intensive care unit in profound CS. His medical history included arterial hypertension, type 2 diabetes, and coronary artery disease. The day prior, he had presented to an external emergency department with STEMI and underwent protected percutaneous coronary intervention with stenting of the left main coronary artery and its bifurcation into the left anterior descending and circumflex coronary arteries in the setting of low cardiac output syndrome (Figure 1). TempMCS with an Impella CP device (Abiomed, Danvers, MA, USA) was insufficient to achieve haemodynamic stability.

Figure 1.

Coronary angiography. (A) right coronary artery; (B) left coronary artery: culprit lesion of the left main coronary artery extending into the bifurcation of the ostial left anterior descending and ostial left circumflex arteries, with 100% stenosis of the proximal left circumflex; (C) implanted Impella; (D) restored blood flow after protected coronary intervention.

On admission, the patient was intubated and required vasopressor support (peak doses: norepinephrine 0.2 µg/kg/min and epinephrine 0.09 µg/kg/min), corresponding to a vasoactive inotropic score (VIS) of 29 and Society for Cardiovascular Angiography and Interventions (SCAI) cardiogenic shock stage D–E.⁵ Blood gas analysis revealed lactic acidosis (pH 7.1, lactate 127 mg/dL).

Transoesophageal echocardiography demonstrated posterolateral ventricular akinesia, a left ventricular (LV) end-diastolic diameter of 57 mm, an LVEF of 13%, and a cardiac index of 1.08 L/min/m². Severe functional MR with an eccentric jet, posterior leaflet tethering, and a valve area of 2.3 cm² was present (Figure 2).

Figure 2.

Intraoperative transoesophageal echocardiography. (A) 2D image (arrow: eccentric wall-hugging jet); (B) 3D imaging; (C) 3D imaging with regurgitant flow (arrow: eccentric wall-hugging jet); (D) Impella device in correct position.

Inadequate LV support, ineffective revascularization, post-infarction ventricular septal defect, and acute MR were considered differential diagnoses. Transoesophageal echocardiography confirmed Impella positioning (Figure 2) and excluded a ventricular septal defect and acute structural mitral pathology. Angiographic results and absence of recurrent ischaemia argued against revascularization failure, identifying severe ischaemic functional MR as the primary driver.

The patient was immediately transferred to the hybrid operating room for escalation to full tempMCS support. However, implantation of an Impella 5.5 device was unsuccessful due to brachiocephalic trunk stenosis. A combined Impella CP and veno-arterial extracorporeal membrane oxygenation (ECMO) system was instituted via the right axillary artery and the right femoral vein, resulting in haemodynamic stabilization with a reduction in catecholamine support to a VIS of 1.67, which was discontinued within 12 h. During tempMCS, anticoagulation was maintained with unfractionated heparin targeting an activated partial thromboplastin time of 60–80 s.

On Day 2 after STEMI, the patient emerged without neurological deficits. ECMO flow was gradually reduced to 2 L/min according to established weaning protocols.^6,7 Explantation was performed 2 days later. Impella support remained necessary, with a stable flow of 1.9 L/min and stable haemodynamics.

Weaning was guided by haemodynamic stability and organ function. Reduction of Impella support to the P2 level resulted in haemodynamic deterioration and worsening of MR to 4+ grade, with a regurgitant volume of 60 mL and an effective regurgitant orifice area of 0.45 cm² (Figure 3), rendering weaning unfeasible. MR severity was assessed at P2 support without vasoactive therapy. The coaptation gap measured 5.7 mm, vena contracta 8.3 mm, tenting height 11.1 mm, and a posterior leaflet length of 15 mm. This resulted in an eccentric, wall-hugging jet with posterior leaflet tethering (Figure 3). The mitral annulus measured 33.5 mm (short axis) and 37.8 mm (long axis), without dilatation. Pulmonary venous flow demonstrated end-systolic reversal in the left upper pulmonary vein. LV unloading reduced the LV end-diastolic volume from 129 to 112 cm³ and end-systolic volume from 109 to 95.5 cm³.

Figure 3.

Echocardiography after explantation with Impella flow reduction. (A) tethering of both mitral valve leaflets (upper white arrow) and papillary muscle (lower white arrow); (B) 2D short-axis view: Impella positioning (left white arrow) and eccentric, wall-hugging jet (right white arrow); (C) 3D imaging; (D) 3D eccentric posterior wall-hugging regurgitation jet.

Given the prohibitive surgical risk (EuroSCORE II 20.2%), the heart team decided to proceed with M-TEER on Impella support. Device selection included the MitraClip and PASCAL (Edwards Lifesciences, Irvine, CA, USA) systems. In the presence of leaflet tethering, increased LV sphericity, and considering continued LV unloading with anticipated post-explantation dilatation, the PASCAL system was considered a suitable option due to its flexible design and broader paddles.

Eight days after STEMI, M-TEER was performed. Following transseptal puncture 36 mm above the annulus, a single PASCAL device was implanted at the A2/P2 segments (Figure 4). If MR reduction was insufficient, P2/P3 would be additionally targeted, with mitral valve surgery as bailout. Intraprocedural MR was reduced to grade <I ‘trace’, with a mean transvalvular pressure gradient of 2.3 mmHg and a mitral valve area of 2.16 cm², fulfilling M-VARC criteria for technical success.⁸ The following day, myocardial recovery with LVEF of 30% was observed and Impella flow was reduced to 1.6 L/min, maintaining a mean arterial pressure of 86 mmHg. The PASCAL device was well seated. The tempMCS was explanted at the bedside the following day.

Figure 4.

Percutaneous transcatheter mitral valve repair with PASCAL. (A) morphology of the mitral valve with a coaptation gap (white arrow) at A2/P2; (B) positioning of the M-TEER device without interference with the Impella system (white arrow); (C) grasping view with trace mitral regurgitation; (D) Impella CP (1), TEE probe (2), delivery catheter positioned in the left atrium (3), and PASCAL device (4).

The patient was discharged to a secondary care hospital on Day 15 after STEMI, with a total in-hospital stay of 26 days. Following tempMCS, prophylactic unfractionated heparin was continued, and dual antiplatelet therapy with aspirin and prasugrel was initiated after exclusion of bleeding complications. At 9-month follow-up, TTE showed an LVEF of 44%, LV end-diastolic diameter of 49 mm, and cardiac index of 3.1 L/min/m². Residual MR was grade <I, with a mean gradient of 2.47 mmHg. The patient presented in New York Heart Association functional class I.

Discussion

The patient’s critical condition required combined Impella and ECMO support, underscoring the key role of tempMCS in stabilizing haemodynamics and enabling subsequent interventions. If tempMCS enables survival from an otherwise fatal shock state, the success of a subsequent valve intervention becomes essential.

Severe functional MR may impede successful weaning from tempMCS by reducing effective forward stroke volume, maintaining elevated left atrial pressure with ongoing pulmonary congestion, and limiting the efficacy of LV unloading as support is decreased. Leaflet tethering and MR severity are dynamic and may worsen under changing loading conditions during weaning attempts. In this context, M-TEER can be considered to stabilize haemodynamics and facilitate device weaning. In this patient, MR severity was markedly reduced following intervention.

M-TEER on tempMCS is rare, with limited data on its use.⁹ Comparative studies are needed to assess device-specific differences in performance, long-term outcomes, and predictors of successful interventions in CS. In the present case, a coaptation gap of 5.7 mm, posterior leaflet tethering, and a non-dilated annulus were associated with rapid recovery and remodelling.

Device selection was guided by anatomical and procedural considerations. The PASCAL system was considered a reasonable option given leaflet tethering and ventricular geometry, as well as device features. Finite element simulations suggest reduced leaflet and annular stress compared to the MitraClip⁹ device, the clinical relevance during withdrawal of LV unloading remains uncertain.

Device selection is crucial for achieving therapeutic goals, including rapid myocardial recovery, while preserving M-TEER as a bridge to surgical mitral valve intervention or heart transplantation.¹⁰ This case supports the feasibility of M-TEER using the PASCAL system in selected patients with functional MR and CS requiring Impella, facilitating tempMCS weaning.

Lead author biography

Daniel Schwarzkopf is a cardiothoracic surgery resident at the Deutsches Herzzentrum der Charité – Universitätsmedizin Berlin. He completed his medical studies at the Universities of Göttingen and Rostock, receiving full medical licensure in November 2023. Prior to medicine, he trained as a registered nurse at Charité Berlin. His primary interests include cardiac surgery and structural heart interventions, currently engaged in the structural heart interventions programme.

Consent: The patient’s written consent for publication of this case report has been provided in accordance to the COPE guidelines and ICMJE recommendations. A patient perspective could not be obtained.

Funding

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Data availability

The data underlying this article will be shared on reasonable request.