Mitral regurgitation accompanying heart failure is a bad problem. Quality of life goes down, hospitalisation goes up, and life gets shortened. In HFrEF the left ventricle dilates and with this the papillary muscles get displaced and the 2 mitral valve leaflets cannot coat or close adequately. Net result is blood gets thrown back with each contraction of the heart and heart failure worsens. This mitral regurgitation is defined as secondary or functional MR.
Unfortunately surgical repair or surgical valve replacement has not been very successful. A device called trans catheter end to end repair has been around for almost a decade and at least one randomised trial done in the US has shown excellent results , in fact some have called them spectacular. 600 patients with moderate and severe MR were randomised to the TEER procedure or to guideline directed medical therapy. At 2 years mortality had been reduced by 37% and hospitalisation by 47% in the TEER group.
With TEER a catheter is negotiated from a groin vein into the right atrium, and from there into the left atrium by puncturing the inter atrial septum, and finally the nitrate leaflets are clipped. The clipping reduces or removes mitral regurgitation.
But unlike the American study a French (also randomised) failed to show any difference in events with TEER compared to guideline directed medical therapy. American researchers explained lack of efficacy because of less sick patients in the French trial.
A sub analysis of the PROVE-HF trial was published in Circulation a week ago, that shows the number of patients with moderate or severe mitral regurgitation halved at 6 months when they were given sacubitril/valsaratan treatment. The salutatory results persisted for 12 months. It must be noted that earlier PROVE-HF had reported an absolute increase of 9.5% in left ventricle ejection fraction on an average at 12 months on sacubitril/valsartan therapy.
Crucially the American (COAPT) trial on TEER had less than 3% patients on sacubitril/valsartan while the French trial had 12.1% on the combination medicine. The patients were obviously not on optimal guideline directed medical therapy.
Hence, in patients with severe heart failure (HFrEF) accompanied by severe mitral regurgitation a trial of drug therapy with sacubitril/valsartan should be tried, because half of these patients may respond and not need the TEER device that is expensive and not without some morbidity. In case the patient does not respond to drug therapy, TEER should be suggested to the patient. It would be a good idea to add an SGLT2 inhibitor to sacubitril/valsartan while waiting for 6 months.
Also an US observation registry has shown a 50% reduction in mortality with TEER in patients with cariogenic shock accompanied by mitral regurgitation at one year follow up. This is not a randomised study but s the observations are hypothesis generating apart from being reassuring. So far nothing has really worked in cariogenic shock, which has a mortality of 50% at 6 months.