Surgical valve replacement in a case of idiopathic dilated cardiomyopathy with massive left atrial dilatation and secondary mitral regurgitation

A 56-year-old patient, known for having idiopathic dilated cardiomyopathy for more than 30 years with chronic atrial fibrillation under vitamin-K antagonist, was admitted for recurrent heart failure episodes despite optimal medical therapy (carvedilol 50-0-50 mg, digoxin 0.25-0-0 mg, torasemid 40-0-0 mg, dapaglifozine 10-0-0 mg, aldactone 25-0-0 mg, sacubitril/valsartan 100-0-100 mg). Cardiac resynchronization therapy was implanted 15 years ago.

Transthoracic echocardiography showed massive left atrial (LA) dilation with LA volume of 1134 mL and index LA volume > 10 times the cutoff value for severe LA dilation (493.9 mL/m², severe > 48 mL/m²; Fig. 1A). The left ventricle (LV) was also severely dilated (end-systolic diameter: 68 mm, end-diastolic diameter: 94 mm). LV ejection fraction (LVEF) was estimated at 45–50%. Mitral regurgitation (MR) was severe (PISA radius 2.4 cm, regurgitant volume 255 mL, effective regurgitant orifice area 23 mm²; Fig. 1B). Transoesophageal echocardiography showed leakage on the whole coaptation line, a 5 mm-coaptation gap, massive annular dilation (7 cm), posterior leaflet length of 13 mm (Fig. 1C–E, Suppl. Video 1). MR mechanism were (posterior > anterior) leaflet restriction (Carpentier-3b) and annular dilation (Carpentier-1), corresponding to a functional and atrial MR. VO_2max was 13 mL/min/kg and pulmonary pressures were normal. The heart team’s decision was to perform levosimendan perfusion, pre-LV assist device assessment and surgical mitral valve replacement (SMVR). A Medtronic 33 mm Mosaic bioprosthesis implantation with LA appendage ligation (50 mm, Atriclip) were performed uneventfully. Post-operative LVEF was 30% and mean gradient 6.5 mmHg (Fig. 1F, G, Suppl. Video 2).

Figure 1.

A. Transthoracic apical four chamber view showing massive left atrium (LA) dilatation with LA volume of 1134 mL; B. Transthoracic apical four chamber view with color Doppler on the mitral valve and the LA showing severe mitral regurgitation; C. Transesophageal three-dimensional image of the mitral valve (atrial view) at mid-systole showing a coaptation gap between the two leaflets (arrowheads); D. Similar to panel C but ventricular view (arrowheads); E. Transesophageal four chamber view (0°), zoomed on the mitral valve, at mid-systole, showing the coaptation gap with leaflet restriction (posterior >> anterior); F, G. Transthoracic apical four chamber view showing the mitral bioprosthesis without (F) and with color Doppler without residual mitral regurgitation (G); LV — left ventricle; LA — left atrium; AL — anterior leaflet; PL — posterior leaflet.

Despite the absence of robust data in favor of SMVR in functional MR (class IIb), SMVR improved patient symptoms. At 1-year follow-up, there was no readmission. Transcatheter edge-to-edge repair was not an appropriate option considering the leaflet flattening and the annular dilation.