We successfully performed coronary artery bypass grafting in a 57-year-old man who had undergone a left pneumonectomy 7 years previously. Because the patient's heart was completely displaced into the left posterior hemithorax, access via a left posterolateral thoracotomy was chosen. Saphenous vein grafts were chosen over the internal mammary artery. The distal anastomoses were performed with use of the off-pump technique; for the proximal anastomosis, 2 venous grafts were implanted into the descending aorta. The patient's postoperative course was uneventful, and postoperative angiography revealed patent grafts. Herein, we discuss the case of this patient, and we present some considerations that can influence surgical approaches in similar circumstances.

A 57-year-old man, who had undergone left pneumonectomy 7 years earlier, presented with symptoms of unstable angina. Examination revealed triple-vessel disease, respiratory dysfunction, and complete displacement of the heart and the great vessels to the posterior wall of the left pleural cavity. Here, we discuss the case of this patient and the management of coronary artery bypass grafting (CABG) when the heart is completely displaced after pneumonectomy.

In July 2007, a 57-year-old man who had undergone left pneumonectomy for epithelial squamous-cell carcinoma (pT3R0M0N0) 7 years earlier was admitted to our hospital with unstable angina. His vital signs were normal. An electrocardiogram revealed normal sinus rhythm at 87 beats/min. Echocardiography showed normal size and structure of the heart, and a left ventricular ejection fraction of 0.80. Cardiac catheterization revealed triple-vessel disease with substantial stenosis of the right coronary artery (RCA), of the middle segment of the left anterior descending coronary artery (LAD), and of the proximal segment of the left circumflex artery (LCx) and its 3rd obtuse marginal branch. Chest radiography and thoracic computed tomography revealed complete displacement of the heart and the great vessels to the posterior wall of the left pleural cavity (Fig. 1). A pulmonary function test showed moderate restrictive and obstructive respiratory dysfunction: forced expiratory volume in the 1st second of 2.24 L (61.9% of predicted value), and forced vital capacity of 3.21 L (70.3% of predicted value). Results of an arterial blood gas analysis were normal. The patient was scheduled for CABG.

Fig. 1 Thoracic computed tomography shows marked leftward and backward displacement of the heart and the great vessels.

Because of the displaced heart, a median sternotomy would not have enabled adequate exposure; therefore, the patient was positioned for a left posterolateral thoracotomy. A suitable segment of the saphenous vein was harvested. The distal anastomoses to the LAD, the obtuse marginal branch, and the RCA were performed with 2 single venous grafts by use of off-pump cardiopulmonary bypass, and the 2 proximal venous grafts were anastomosed to the descending aorta.

The patient was weaned from the respirator 10 hours after the surgery, and his postoperative course was uneventful. He was discharged from the hospital on the 9th postoperative day. Coronary angiography on the 12th day showed that the grafts were all patent and functioning well.

When open-heart operations are necessary in patients who have undergone pneumonectomy, the unavoidable shift of mediastinal structures should be carefully considered. Preoperative computed tomographic scanning to evaluate the altered anatomic relationships is strongly recommended. Various anatomic and procedural aspects should be anticipated. First, exposure of the heart, the great vessels, and the target coronary artery may be very difficult via a median sternotomy. In our patient, 1 alternative incision—a left posterolateral thoracotomy—enabled adequate access to the left main coronary artery, the LAD, the LCx, and the RCA. Second, it may be difficult to institute standard cardiopulmonary bypass by means of aortic and right atrial cannulation. These standard cannulation techniques may need to be modified by, for example, the use of direct bicaval cannulation, femoral vein cannulation, or cannulation through the pulmonary artery into the right ventricle.¹ However, the off-pump technique is most commonly used, as in our patient. Even in patients who have multiple-vessel lesions, hybrid myocardial revascularization is another option.² This approach involves the anastomosis of 1 venous graft to the LAD and the placement of stents in the left main coronary artery and in the ostial and proximal lesion of the LCx. Third, it is difficult to perform a proximal anastomosis to the ascending aorta, due to the displacement and rotation of the ascending aorta and to severe adhesion of the thoracic cavity, so proximal anastomoses to the descending aorta might be advisable.

Consequent to the displacement and rotation of the heart and to hyperinflation of the contralateral lung, the internal mammary artery (IMA) may not be useful as a graft to the target vessel, because of the risk of IMA stress and tension. Then too, harvesting of the IMA may decrease pulmonary function and increase the risk of injury to the phrenic nerve.^3,4 Therefore, venous grafts have reportedly been used in most CABG procedures after pneumonectomy. In our patient, we chose saphenous vein grafts chiefly because the pedicle of the left IMA could not reach its target vessel (the LAD) without being subjected to substantial tension.

Pulmonary function, which is inherently reduced after pneumonectomy, becomes even worse after CABG. Although the risk of pulmonary complications increases, no deaths from respiratory failure have been reported in cases of CABG after pneumonectomy. Therefore, there is no general contraindication for open-heart surgery in these special circumstances. Nevertheless, it is prudent to give careful preoperative consideration to pulmonary function. Hockmuth and Mill⁵ recommend restricting the acceptance of surgical candidates to those who have a forced expiratory volume in the 1st second of more than 800 mL and no less than 40% of predicted values. Such patients' resting carbon dioxide tension should not exceed 50 mmHg, and their diffusion capacity of carbon monoxide should be more than 50% of predicted values. These authors also suggest selecting as surgical candidates only those patients whose pulmonary artery systolic pressure is less than 40 mmHg. Beyond this, there are no general recommendations for the management of patients who undergo CABG after pneumonectomy.