HOW TO TREAT 29
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HOW TO TREAT 29
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Figure 3. Segmental anatomy of the mitral valve.
Figure 4. Gross pathology of rheumatic heart disease. The left ventricle has been cut open to display characteristic severe thickening of mitral valve, thickened chordae tendineae and hypertrophied left ventricular myocardium. data. 13 This technique mimics the surgical Alfieri edge-to-edge leaflet repair and attaches the free edges of the anterior and posterior leaflets with a clip. 23
The 2011 EVEREST II( Endovascular Valve Edge-to-Edge Repair Study) trial included 279 patients randomly assigned to either mitral clip or surgery. It showed that percutaneous repair, although less effective in reducing MR than surgery, was associated with improved left ventricular dimensions, improvement in New York Heart Association class and in quality of life. 21 Since this trial, real life registry data have confirmed the safety and efficacy of percutaneous MV edge to edge repair in patients with primary MR and prohibitive surgical risk. 24
Secondary mitral regurgitation
Unlike primary MR, secondary MR is not a disease of the MV but a disease of the cardiac chambers that surround the MV apparatus. Secondary MR usually occurs because of LV or left atrial remodelling and enlargement, which causes papillary muscle displacement and / or annular dilatation. Another cause may be isolated posterior leaflet tethering in preserved LVEF following myocardial infarction. 1, 12
Given the aetiology is heterogenous and the MV structure is not the culprit, treatment focuses on the mechanism of the MR. In patients with a dilated ventricle, guideline-directed medical therapy, including device therapy( cardiac resynchronisation therapy), is first line and arguably the most important
20, 20A line of therapy.
In ischaemic MR, in addition to medical therapy, consider the indications for coronary revascularisation. 13 Studies in patients with heart failure and secondary MR have shown improvements in both mortality and in quality of life scores with guideline-directed medical
11, 25 therapy.
INTERVENTION Consider intervention if
guideline-directed medical therapy fails. Decisions are made based on the recommendations of a multidisciplinary heart team.
In the case of functional MR associated with coronary artery disease, MV repair or replacement at the time of bypass surgery improves symptoms and survival, and should be considered. 26 In isolated secondary MR, the evidence to support surgical intervention remains limited because of the enormous procedural risks, high recurrence rates and lack of mortality benefits. 27
In high-risk surgical patients, TEER is a viable option. The 2018 COAPT( Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation) trial randomly assigned more than 600 patients with symptomatic MR and reduced LVEF to either TEER plus guideline-directed medical therapy or guideline-directed medical therapy alone. 28 This trial showed that TEER was a safe procedure with a very low complication rate. Patients in the TEER arm had significantly fewer hospitalisations for heart failure and improved survival at two years. 28
Interestingly, the MITRA-FR( Multicentre Study of Percutaneous Mitral Valve Repair MitraClip Device in Patients With Severe Secondary Mitral Regurgitation) trial, which randomised 300 patients to either medical therapy alone or TEER and medical therapy, showed no difference between the groups. 29
A possible explanation for the different findings between these two studies is the timing of the intervention relative to the LV size and the severity of MR.
The patients enrolled in the COAPT trial had more severe MR and less advanced LV disease compared with those in the MITRA-FR trial, indicating that those with too severe LV dilation / dysfunction may not benefit from the MitraClip procedure. The benefits of intervention are thought to be greater when the degree of MR is disproportionate to what is expected for the ventricular
Figure 5. Medical illustration of human torso with the placement points for stethoscope and percussion exams for a patient with mitral insufficiency( mitral regurgitation), front view. Circles indicate stethoscope placements and coloured zones for percussion.( u-) represents heart sounds at the base;(-u) represents heart sounds at the apex;( uL) represents second heart sound accentuated( r) murmurs.