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Use of 99Tcm-MIBI scintigraphy in the evaluation of perfusion improvement after myocardial revascularization with the use of the left internal thoracic artery


Nuclear Medicine Communications: February 2001 - Volume 22 - Issue 2 - p 183-188
Review Article

In spite of successful revascularization, in a significant group of patients myocardial ischaemia is present after surgery. The final effect of surgery depends on preoperative left ventricular function, initial coronary artery status, completeness of revascularization, the use of arterial or venous grafts, and many other factors. The aim of our 99Tcm-MIBI scintigraphy study was to examine the improvement of perfusion in the left anterior descending artery (LAD) vascular territory after revascularization with the use of the left internal thoracic artery (LITA), with respect to the LAD diameter and use of additional venous graft to diagonal artery. The study group consisted of 45 subjects (42 male, three female) aged 34-68 years (mean age 50.9±8.3 years) recruited from patients in whom LITA was grafted into LAD. The operation and postoperative period was uneventful in all patients. Two weeks before, and 3-4 months after surgery, dipyridamole-rest sestamibi SPECT were performed. The revascularization significantly improved both stress (δPI = 0.77±0.66; P<0.001) and rest (δPI = 0.32±0.60; P<0.001) perfusion of the LAD territory. The improvement was slightly better in patients who received two grafts (δPI = 1.42±0.91) for the LAD territory in comparison to the group revascularized only with LITA (δPI = 0.80±0.69; P = patients who received an arterial bypass to the LAD artery the perfusion was abnormal in all eight patients after anterior myocardial infarction and in 39% of patients without a history of infarction. The perfusion improvement was the best when the diameter of LAD was ≥1.5 mm (δPI = 0.88±0.95). The independent predictors of perfusion improvement were the number of segments with reversible perfusion defect within the revascularized area (β = 0.84, P<0.001), the diameter of revascularized artery (β = 0.17, P = 0.03) and the presence of pathological Q wave at preoperative ECG (β = −0.20, P = 0.02). We conclude that the degree of perfusion improvement in the LAD territory after revascularization with the use of LITA depends on the diameter of bypassed coronary artery, completeness of revascularization and the reversibility of preoperative perfusion defect.

Departments of 1Cardiac Surgery, 2Cardiology and 3Endocrinology, The University School of Medical Sciences, Poznan´, Poland

*Address all correspondence to Dr Marek Jemielity, Department of Cardiac Surgery, Institute of Cardiology, ul. Druga 1/2, 61-848 Poznan´, Poland. e-mail:

Received 8 May 2000, and accepted 11 June 2000

© 2001 Lippincott Williams & Wilkins, Inc.