fix functional MR in heart failure patients with reduced EF

The patient has heart failure with reduced ejection fraction (HFrEF) with functional (secondary) MR on the basis of left ventricular enlargement. The stem specifies that the MR is severe, but the given data also satisfy echocardiographic criteria (regurgitant volume >60 mL, effective regurgitant orifice ≥0.4 cm2). He has an inadequate response to a good regimen of guideline-directed medical therapy, with titration limited by hypotension. Percutaneous transcatheter edge-to-edge repair (TEER, most commonly done with the MitraClip™ device in the United States) is an adaptation of a surgical technique (Alfieri repair) that sutures together the middle segments of the anterior and posterior mitral valve leaflets, forming a figure of 8 and decreasing the size of the regurgitant orifice; the TEER procedure uses a clip placed percutaneously with a catheter passed through the foramen ovale to achieve the same result.

TEER was shown in the randomized COAPT trial to decrease the primary endpoint of annualized heart failure hospitalizations at 2 years (35.8% vs 67.9%) and with further 5-year follow-up, TEER also decreased all-cause mortality (57% vs 67%). Eligibility criteria included HFrEF with at least moderate to severe functional MR and symptomatic heart failure despite maximally tolerated doses of guideline-directed medical therapy for heart failure and resynchronization therapy when appropriate. Left ventricular end-systolic dimension >7 cm was an exclusion criterion. Cardiogenic shock was also an exclusion criterion, and TEER has not been shown to improve outcomes in refractory shock even in the presence of severe MR. The patient in the current case has heart failure and pulmonary hypertension with severe functional MR despite apparent improvement of pulmonary congestion on physical examination and is thus a good candidate for TEER.

A trial concomitant with the COAPT trial, the MITRA-FR trial, did not show a benefit of TEER using the same device. The entry criteria regarding baseline medical therapy were less stringent than COAPT, stressing the need to maximize medical therapy before referral for TEER. There was no exclusion for left ventricle size, and further analysis suggested that many of the patients in MITRA-FR had very large left ventricles that limited the benefit of edge-to-edge repair. This led to the concept of MR proportionate or disproportionate to left ventricle size, with greater benefit in a population of patients with disproportionate MR as in COAPT and less benefit in those with proportionate MR. A ratio of regurgitant volume to left ventricular end-diastolic volume of ≥0.2 has been proposed as a cutoff for disproportionate MR, with one study showing lower rates of all-cause mortality. In this patient, that ratio was 0.36.

Ensuring that a CRT-D device is appropriately configured to provide maximal resynchronization is reasonable but rarely produces dramatic clinical improvement and is best done in a steady state as an outpatient rather than during an inpatient stay. Implantable pulmonary artery pressure monitors can detect increases in filling pressures prior to worsening of symptoms in outpatients and have been shown to decrease heart failure hospitalization. Continuous inotropic therapy may provide symptomatic relief in some patients with refractory HFrEF, albeit at a cost of a somewhat increased mortality; however, this has not been shown to improve outcomes and is not preferable to TEER in this context.123456

Footnotes

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  2. Grayburn PA, Sannino A, Packer M. Proportionate and disproportionate functional mitral regurgitation: a new conceptual framework that reconciles the results of the MITRA-FR and COAPT trials. JACC Cardiovasc Imaging. 2019;12(2):353-362. PubMed ↩

  3. Namazi F, van der Bijl P, Fortuni F, et al. Regurgitant volume/left ventricular end-diastolic volume ratio: prognostic value in patients with secondary mitral regurgitation. JACC Cardiovasc Imaging. 2021;14(4):730-739. PubMed ↩

  4. Obadia JF, Messika-Zeitoun D, Leurent G, et al; MITRA-FR Investigators. Percutaneous repair or medical treatment for secondary mitral regurgitation. N Engl J Med. 2018;379(24):2297-2306. PubMed ↩

  5. Stone GW, Abraham WT, Lindenfeld J, et al; COAPT Investigators. Five-year follow-up after transcatheter repair of secondary mitral regurgitation. N Engl J Med. 2023;388(22):2037-2048. PubMed ↩

  6. Stone GW, Lindenfeld J, Abraham WT, et al; COAPT Investigators. Transcatheter mitral-valve repair in patients with heart failure. N Engl J Med. 2018;379(24):2307-2318. PubMed ↩