Brief Case Description

The patient is a 60 year-old  female with a recent history of non-ST-elevation anterior myocardial infarction  and congestive heart failure. She has a past medical history of hypertension,  diabetes, hyperlipidemia, peripheral vascular disease, stroke and remote  myocardial infarction. She has a known history of coronary artery disease with  multiple previous percutaneous coronary interventions.

Transthoracic echocardiography (TTE) showed  type IIIb mitral valve dysfunction with predominantly restricted leaflet motion  of the posterior leaflet (parasternal long axis and four chamber views). Doppler  echocardiography showed moderate mitral regurgitation with a posteriorly directed  jet. Quantitative measurement revealed a regurgitant orifice area of 28 mm2 and  a regurgitant volume of 46 mL. Pisa radius was calculated at 0.8 cm. Left  ventricular end diastolic diameter was 5 cm and left ventricular ejection  fraction was 33%.

Cardiac  catheterization showed severe three vessel coronary artery disease: left anterior  descending artery with mid total occlusion, first obtuse marginal 80% in-stent  restenosis, proximal right coronary artery 70% in-stent restenosis, and  posterior descending artery (PDA) branch 95% stenosis. Left ventricular ejection  fraction was 30%.

The patient was  referred for coronary revascularization and reconstructive mitral valve  surgery.

 Operative Procedure

 Intraoperative Transesophageal  Echocardiography (TEE)

Intraoperative  transesophageal echocardiography confirmed the diagnosis of type IIIb mitral  valve dysfunction (mid esophageal long axis and four chamber views). Doppler  echocardiography showed mild (2+) mitral regurgitation with a central jet (mid  esophageal four chamber and mitral commissural views). A transgastric  basal short axis view of the mitral valve is  also shown.

In this case, we  observed a reduction in the severity of mitral regurgitation when comparing preoperative  TTE with intraoperative TEE. It is important to note that intraoperative TEE  often downgrades the severity of mitral regurgitation in patients with type  IIIb dysfunction. The mechanism underlying this phenomenon is the unloading  effect of general anesthesia which results in arterial and venous dilatation,  decreasing afterload and preload respectively.

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 the  obtuse marginal and PDA branches.

 Mitral Valve Analysis

Following the exposure  of the mitral valve, we first confirmed the echocardiographic findings by observing  a tethering of both anterior and posterior leaflets which predominated at the  level of P2, P3, and PC area. There was also a significant deformity of the  posterior mitral annulus.

 Following this  echocardiographic and operative 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 deformity

 Dysfunction: Type IIIb

Reconstructive Procedure

 The patient underwent  an undersized remodeling mitral annuloplasty  with the implantation of a size 28 mm Carpentier-McCarthy-Adams IMR  ring. 

Postbypass Transesophageal  Echocardiography

 Postbypass  transesophageal echocardiography showed a competent mitral valve with minimal  residual regurgitation.

 Transgastric basal short  axis, mid esophageal mitral commissural and four chamber views showed the  mitral valve with good leaflet coaptation. Mid esophageal long axis view with  color Doppler interrogation showed a competent mitral valve with no residual  regurgitation.

The postoperative  course was uneventful and the patient was discharged home on postoperative day  seven.