Percutaneous bail-out in severe acute mitral regurgitation: when surgery is not an option.

This editorial refers to ‘A case report of transcatheter mitral valve repair in patient with severe acute mitral regurgitation, cardiogenic shock and left atrial appendage thrombus as a rescue therapy. Facing all enemies at once!’, by N.S. Alachar

Functional mitral regurgitation (FMR) worsens heart failure (HF) prognosis, fuels HF progression, and causes an excess mortality. Percutaneous edge-to-edge repair has been proven effective and safe in patients with severe functional mitral regurgitation (MR) at high surgical risk. Beneficial effects in this patient population include reduction in the rate of HF hospitalizations, and improvement in survival, quality of life, and functional capacity. Conversely, patients with acute MR, either ischaemic or disruption of different parts of the mitral valve apparatus, may require urgent surgical revascularization with concomitant repair or replacement. However, certain scenarios may complicate or preclude surgical procedures, such as a poor clinical state resulting in prohibitive surgical risk. Here, a comprehensive evaluation by the multidisciplinary heart team is essential to ponder further therapeutic options.

In this issue of European Heart Journal—Case reports, Alachar et al. report a case of transcatheter edge-to-edge mitral valve repair (TMVR) in combination with the Sentinel cerebral protection device in a patient suffering from acute ischaemic MR and left atrial thrombus. In detail, a 59-year-old female patient experienced a sub-acute stent thrombosis 3 weeks after stent implantation in the left circumflex artery causing severe FMR based on a restrictive posterior mitral valve leaflet. After an initial clinical stabilization had been achieved, transoesophageal echocardiography revealed additionally the presence of a thrombus in the left atrial appendage (LAA). Since cardiac magnetic resonance imaging (CMR) demonstrated akinesia and transmural scar of all lateral left ventricular segments coronary reperfusion was deemed futile. In the subsequent days, the patient’s clinical state dramatically deteriorated, requiring vasopressor therapy and cardioversion due to ventricular tachycardia, rendering mitral valve surgery not a feasible option according to the local heart team. Therefore, the authors performed successful TMVR with concomitant use of a cerebral protection device (CPD) as a rescue therapy. The patient was discharged from the intensive care unit haemodynamically stable and without neurological deficits 2 days after the procedure.

Documented experience with TMVR in acute MR is scarce and mainly limited to small case series., However, when treating FMR in the setting of acute ischaemia revascularization represents the first therapeutic target. If haemodynamic instability driven by severe FMR persists despite coronary revascularization, the valvular lesion should be treated next. In this specific case, coronary intervention was deemed futile due to the presence of transmural scar detected by CMR further highlighting the significance of multi-modality imaging in valvular heart disease. Furthermore, in the context of the current guidelines, surgery remains the gold standard for treating acute MR in the setting of myocardial infarction., However, FMR patients frequently suffer from multiple co-morbidities with an associated excess in surgical risk, which renders TMVR an attractive alternative treatment option. Shared decision-making enforced by the heart team is indispensable in these cases.

Another important aspect of this case is the use of cerebral protection in the presence of LAA thrombus, which usually represents a contraindication for TMVR. In patients undergoing transcatheter aortic valve replacement, the use of the Sentinel dual-filter protection device has been shown to be associated with a significantly lower rate of peri-procedural stroke compared with unprotected procedures. Potential sources of cerebral embolism during transcatheter mitral valve interventions include mitral annulus calcification (MAC), thrombotic material from either the LAA or devices, clip dislocation, and atrial, valvular or ventricular damage. Reported rates of in-hospital stroke during TMVR range from 0.2 to 1.2%, but certainly the occurrence of stroke will be much more likely in the presence of LAA thrombus, such as seen in this case. As for now, the use of CPD is not part of procedural routine in TMVR. However, it undoubtedly represents a highly valuable tool specifically considering the increasing numbers of mitral valve-in-valve, valve-in-ring, and valve-in-MAC interventions with a high risk of cerebral embolism.

In conclusion, the present case is a valuable demonstration that outside the box thinking enabled physicians to safely guide a challenging patient through a plethora of potentially life-threatening conditions. In this acute setting, TMVR may serve as arescue option for patients deemed inoperable after careful heart team discussion. Cerebral protection with the Sentinel device prevented embolic stroke in this patient, who had no other therapeutic option.

Lead author biography

Dr. Nitsche started his PhD postgraduate studies in the work group of Prof. Dr. Mascherbauer at the Division of Cardiology of the Medical University of Vienna. Main areas of research are valvular heart disease, in particular aortic stenosis and mitral regurgitation, and multimodality imaging, including cardiac magnetic resonance, echocardiography, and nuclear imaging. His research yielded multiple publications as a first author in high-ranked cardiology journals. For his work “Prevalence and Outcomes of Concomitant Aortic Stenosis and Cardiac Amyloidosis” which originated from an Austrian-UK collaboration and which was published in the “Journal of the American College of Cardiology” he received the publication award of the Austrian Society of Cardiology in 2021.

Conflict of interest: None declared.

Funding: None declared.