Off-pump surgery for coronary artery disease combined with mitral stenosis

Rheumatic heart disease is still highly prevalent in developing countries where the incidence of coronary artery disease (CAD) is also arising. Consequently the occurrence of coexistent CAD and mitral stenosis (MS) dominantly caused by rheumatic fever is more frequent in these countries. Comorbidities such as pulmonary and renal dysfunction occur frequently in these aging populations. Off-pump surgery is widely applied in patients with concomitant CAD and severe comorbidities due to lower incidence of postoperative morbidity. Closed mitral commissurotomy (CMC) is a well established treatment for patients with mitral stenosis. We report here a case of moderate stenosis combined with seriously diffuse 3-vessel CAD and severe chronic obstructive pulmonary disease (COPD) in an elder male treated with off-pump coronary artery bypass (OPCAB) plus CMC. A 72 years old man was referred for crescendo angina and dyspnoea on exertion (New York Heart Association classification III) with a history of inferior myocardial infarction two years earlier and rheumatic fever for 30 years. The electrocardiogram demonstrated sinus rhythm and ST depression in precordial leads. The echocardiography showed moderate stenosis with a mitral valve orifice area (MVA) of 1.25 cm2 (Figure 1A), and a left ventricular ejection fraction of 63%. Wilkins echocardiographic score was 5 (thickening 2, mobility 1, subvalvular disease 2 and calcification 0). Thrombi in the cardiac chambers were excluded by transesophageal echocardiography. Coronary angiogram revealed 3-vessel CAD with significant stenosis in all main coronary branches (left anterior descending artery (LAD), 90%; left circumflex artery (Cx), 90%; right coronary artery (RCA), 100%) and SYNTAX score was 36. He also complained of cough and sputum and pulmonary function tests using the Global initiative for Chronic Obstructive Lung Disease criteria revealed a severe COPD.Figure 1.: Preoperative echocardiography shows a MVA of 1.25 cm2 (A). Intraoperative transoesophageal echocardiography reveals a MVA of 1.88 cm2 (B). Postoperative echocardiography shows a mitral valve orifice area of 1.71 cm2 (C). Postoperative coronary angiogram demonstrates patent LIMA to LAD and patent SVG to DI, OM and PDA. LIMA: left internal mammary artery graft; LAD: left anterior descending artery; SVG: saphenous vein graft; DI: diagonal artery; OM: obtuse marginal branch; PDA: posterior descending artery (D).Standard median sternotomy incision was used for the exposure of the heart. OPCAB was performed with left internal mammary artery (LIMA) to LAD and saphenous vein graft to diagonal artery, obtuse marginal branch and posterior descending arteries sequentially. The blood flow in LAD, diagonal artery, obtuse marginal branch and posterior descending artery was 48 ml/min, 20 ml/min, 25 ml/min and 38 ml/min respectively determined by flowmeter. Afterwards CMC was performed by standard transatrial and transventricular technique using a left Tubbs dilator. The dilator was adjusted to 26 mm diameter, advanced into the mitral orifice from the apex under the guiding of finger and triggered to expand the mitral annulus. Then a transesophageal echocardiography revealed a satisfactory MVA of 1.88 cm2 (Figure 1B). The patient was extubated 7 hours postoperatively and discharged on the ninth postoperative day after an uneventful recovery. At the 10-year follow-up, the patient presented in good conditions excluding exertive physical actions. The electrocardiogram demonstrated sinus rhythm and no ST changes. Echocardiographic examination showed a normal MVA of 1.71 cm2 (Figure 1C), a left ventricular ejection fraction of 58% and no thrombi in cardiac chambers. Coronary angiogram revealed all the bridged grafts were patent (Figure 1D). Advanced stages of COPD, especially severe forms, are associated with early mortality following cardiac surgeries using cardiopulmonary bypass (CPB).1 CPB is the trigger of inflammatory responses and associated with atelectasis identified as the major causes of post-CPB pulmonary dysfunction and therefore increase postoperative morbidity and mortality.2 Off-pump surgery capable of maintaining favourable blood gas and airway pressure was sufficient to protect pulmonary function from deterioration in this elderly patient with preexisting severe COPD. Percutaneous coronary intervention (PCI) and OPCAB are procedures without CPB. SYNTAX score has a predictive value in PCI and coronary artery bypass grafting (CABG) aiming at offering optimal revascularization method in patient with complex CAD. The coronary lesions with a SYNTAX score of 36 were more suitable for CABG in this patient. We performed OPCAB first to improve myocardial ischemia and enhance myocardial tolerance during mitral reconstruction. CMC is a well established treatment for MS with favourable morphology (echocardiography scores of less than 8 and no mural thrombus). For this patient with a Wilkins echocardiographic score of 5, CMC was indicated. The impressive effects of CMC in both short- and long-term follow-ups have been well documented.3 Moreover, it is easy to control valve dilation and obtain optimal MVA during CMC via intraoperative transoesophageal echocardiography. CMC is compatible with off-pump surgery, which makes it possible to treat CAD and MS simultaneously for the patient with complex diseases. Currently, percutaneous balloon mitral valvotomy (PBMV), a less invasive procedure, combined with OPCAB is performed in one stop hybrid operating room. Furthermore, for the patients with coexistent less severe CAD and MS with favourable morphology, PCI plus PBMV may be recommended. The favorable outcomes at the ten-year follow-up suggest that this combined off-pump surgery was feasible and effective in high-risk patient with coexistent CAD and MS.