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.

Operative Procedure

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.

Reconstructive Procedure

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 .