Brief Case Description
A 79-year-old female presented with new onset dyspnea on exertion and exertional class II-III angina. She has a past medical history of hypertension, diabetes, hyperlipidemia and prior postero-lateral myocardial infarction. She has a known history of coronary artery disease and underwent percutaneous intervention of right coronary artery (RCA).
Transthoracic echocardiography showed type IIIb mitral valve dysfunction. Doppler echocardiography showed a central jet and mitral regurgitation was graded moderate to severe. Left ventricular end diastolic diameter was calculated at 6.9 cm and left ventricular ejection fraction was 38%.
Cardiac catheterization showed severe three-vessel coronary artery disease: left anterior descending artery 70-80% stenosis, first obtuse marginal 70-80% stenosis, posterolateral branch 70-80% stenosis, and proximal RCA 70-80% in-stent restenosis. Left ventricular ejection fraction was 42%. Pulmonary artery pressure was 40/28 mmHg.
The patient was referred for coronary revascularization and reconstructive mitral valve surgery.
Intraoperative Transesophageal Echocardiography
Mid esophageal long axis view showed type IIIb mitral valve dysfunction involving both leaflets. The P2 segment was thickened with minor annular calcification. Mid esophageal four chamber view confirmed the diagnosis of type IIIb dysfunction and revealed a concentric jet of mitral regurgitation. The vena contracta demonstrated moderate mitral regurgitation. One could also see that there was thickening and calcification on the posterior leaflet. These valvular lesions, however, were not at the origin of significant valvular regurgitation.
Three-dimensional rendering of the mitral valve showed type IIIb dysfunction as indicated by the blue leaflet coloration representing restricted leaflet motion. There was also calcification of P3 segment with type IIIa dysfunction.
Coronary Artery Bypass Grafting (CABG)
The patient underwent coronary artery bypass grafting with the left internal mammary artery to the left anterior descending artery and saphenous vein graft from the aorta to RCA, diagonal, and obtuse marginal branches.
Mitral Valve Analysis
Following the exposure of the mitral valve, we first confirmed the echocardiographic findings by observing a tethering of both mitral leaflets. We also identified associated lesions such as P3 segment calcification and annular deformity with dilatation.
Following this complete valve analysis, we can summarize the pathophysiological triad as follows:
Etiology: Ischemic mitral valve disease
Lesions: papillary muscle displacement with leaflets tethering, and secondary annular dilatation
Dysfunction: Type IIIb
There was also a second component which was type IIIa dysfunction of the P3 segment with leaflet thickening and calcification. It is important to note that the etiology of this valvular lesion is a degenerative process due to the aging and not rheumatic fever.
We first performed resection of the secondary chordae of P2 and P3 segments to increase their mobility. We then continued with an undersized remodeling annuloplasty with the implantation of a size 30 mm Carpentier Edwards Physio ring. The prosthetic ring was downsized by one size. We avoided severe downsizing to minimize the risk of mitral stenosis as a type IIIa component was also present.
Postbypass Transesophageal Echocardiography
Postbypass transesophageal echocardiography showed a competent mitral valve with minimal residual regurgitation. Transgastric basal short axis view showed the mitral valve with good leaflet coaptation. Mid esophageal long axis view showed the mitral ring in place and an increased coaptation surface area. Mid esophageal long axis view with color doppler interrogation of the mitral valve revealed a small posterior jet. Mid esophageal four chamber view confirmed the good implantation of the ring with adequate surface of coaptation. A slight modification of the four chamber view to interrogate the regurgitation jet revealed minimal regurgitation.
Three-dimensional rendering of the mitral valve showed the prosthetic ring, and opening and closing motions of the valve during diastole and systole respectively. As shown here, almost the entire height of the posterior leaflet contributed to the surface of coaptation during systole except for a portion of calcified P3 segment .