Myocardial infarction during left upper lobectomy in a patient with a LIMA graft.
A 65-year-old man presented to our institution with a 3 cm, biopsy-proven non-small cell lung cancer in the left upper lobe. Preoperative evaluation revealed a history of diabetes mellitus, heavy smoking and coronary artery bypass grafting four years ago, including an in situ LIMA graft to LAD coronary artery and a saphenous vein graft from the aorta to the obtuse marginal artery. Echocardiography and pulmonary function test were within normal limits. A coronary angiogram demonstrated that the LIMA and saphenous vein grafts were patent and not narrowed. Computed tomography of the chest showed the left upper lobe lung tumor sparing the LIMA.
The patient was scheduled for a left upper lobectomy. Cardiac medications were continued until the morning of surgery. General anaesthesia, selective lung ventilation and intraoperative monitoring were achieved according to standard practices in thoracic surgery. A left lateral thoracotomy was made and dense adhesions around the left upper lobe were carefully dissected under direct vision. Despite a very stable haemodynamic status, the patient presented suddenly an ST-segment depression of more than 0.3 mV on the ECG lead V positioned on the anterior left third intercostal space. The LIMA pedicle was rapidly identified and surgical injury ruled out. Blood flow in the LIMA graft was assessed by Doppler and found to be decreased. Significant ST-segment depression persisted in spite of papaverine local irrigation as well as nicardipine, nitroglycerine and heparin intravenous perfusions. The option of LAD coronary artery revascularisation by an emergency percutaneous angioplasty or coronary artery surgery was discussed but finally declined. The left upper lobe was removed en bloc and the integrity of the LIMA graft checked before chest closure. Postoperatively, the patient presented electrocardiographic changes as significantly deepened Q waves at leads V1 to V3, and increased myocardial isoenzyme Troponin I above 2 ng/ml. Echocardiography showed a regional anterior wall motion abnormality with a conserved global myocardial function. The patient had no other cardiac or respiratory complications and left the hospital on the seventh postoperative day under appropriate medication.
This case highlights the potential risk of arterial graft injury and acute myocardial ischaemia in patients undergoing left upper lobectomy with previous LIMA to LAD bypass. Compression or retraction of the LIMA pedicle during surgical dissection has probably caused an arterial spasm, a decreased blood flow to LAD coronary artery and an anterior myocardial infarction. Greene et al reported, in a similar context, a transient intraoperative ST-segment depression without postoperative ECG changes or myocardial isoenzyme leak (2). Intraoperative management of patients with previous CABG surgery undergoing left upper lobectomy should focus on haemodynamic and ST-segment monitoring as well as on the availability of pharmacological and mechanical cardiovascular support in case of LIMA graft injury and myocardial infarction. Emergency coronary revascularisation by embolectomy, percutaneous angioplasty or coronary artery surgery should be considered but its efficacy in this specific context has not been reported.
(1.) Halkos ME, She 1. rman AJ, Miller JI. Preservation of the LIMA pedicle after cardiac surgery in left upper lobectomy. Ann Thorac Surg 2003; 76:280-281.
(2.) Greene PS, Heitmiller RF. Lung cancer and the left internal 2. mammary artery graft. Ann Thorac Surg 1994; 57:1029-1030.
(3.) Singhatanadgige S, Sindhvanada W, Kittayarak C. Left upper 3. lobectomy after CABG with the left internal mammary artery graft. J Med Assoc Thai 2006; 89:887-889.
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|Title Annotation:||Correspondence; left internal mammary artery|
|Author:||Yazigi, A.; Jabbour, K.; Madi-Jebara, S.; Haddad, F.; Hayeck, G.; Tabet, G.|
|Publication:||Anaesthesia and Intensive Care|
|Date:||Mar 1, 2009|
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