Abstract
Postoperative angina is generally caused by subclavian artery stenosis or flow diversion in anomalous or large unligated side branches of the left internal mammary artery. Previously, surgery was the treatment method for unligated side branches, but with the improvements of interventional techniques, it is shown that endovascular treatment is also effective in these patients. Herein, we present successful endovascular treatment of a large unligated intercostal side branch causing recurrent angina.
1
Introduction
The left internal mammary artery (LIMA) is the preferred native graft for myocardial revascularization owing to its favorable long-term patency and resistance to atherosclerosis. Recurrent angina after surgical myocardial revascularization is generally caused by progression of coronary artery disease or occlusion of the LIMA bypass grafts . A rare cause of postoperative angina is coronary steal syndrome, which is caused by a proximal subclavian artery stenosis or flow diversion in anomalous or large unligated side branches of the LIMA . The LIMA branches are surgically ligated before performing bypass grafting . However, some side branches may be unligated because of minimal invasive procedures or anatomical variants .
In this paper we report effective percutaneous treatment of a coronary steal due to a large unligated side branch of the LIMA in a patient presenting with angina 1 year after coronary artery bypass (CAB) surgery.
2
Case report
A 53-year-old man underwent coronary bypass grafting for coronary artery disease in May 2002. He received a LIMA–LAD anastomosis. In January 2003, he presented with angina on minimal exertion. Angina persisted despite medical therapy. There were no significant findings on physical examination. Electrocardiogram (ECG) did not display any recent ischemic changes. Cardiac enzymes (troponin T, CK, CK-MB) were all negative. Patient relieved stress test-induced angina and depression of the ST segment in leads V4 to V6. In addition, myocardial perfusion scintigraphy (21 mCi Tc-99m stress SPECT) yielded reversible anterolateral wall ischemia. Coronary angiography demonstrated a large patent first intercostal branch and significant reduction in the lumen of the distal LIMA compared to its proximal part, with poor filling of the grafted coronary artery ( Fig. 1 ). This appeared to be the only cause of anginal symptoms in this patient. Therefore, we decided to occlude the intercostal side branch after receiving informed consent of the patient. The internal mammary artery was selectively catheterized with a 6F guiding catheter (Envoy, Cordis Europe NV, Roden, the Netherlands). Through this guiding catheter, a Microcatheter system [Rapid Transit, Cordis Neurovascular (Miami, FL, USA) and microguidewire (Terumo, Radiofocus Guidewire GT, Tokyo, Japan)] was inserted and the intercostal artery was superselectively catheterized. We measured the diameter of the collateral vessel to select occlusion coils size. Afterward, two 0.018″ electrically detachable platinum microcoils (Micrus, CA, USA), 2 and 3 mm in diameter, were introduced through the coaxial catheter and used to occlude this side branches. The coils were either 2 cm long. Angiography after the deployment of the coils showed complete occlusion of the intercostal side branch. There was significant improvement in filling of the internal mammary artery and grafted coronary artery ( Fig. 2 ). The patients’ exercise tolerance improved significantly and findings of stress test-induced angina on ECG disappeared. We used anticoagulation (heparin iv bolus 5000 U and continued with 1000U/h iv infusion) during the occlusion procedure. The patient was subsequently angina-free and is still asymptomatic 2 years after coil embolization.
2
Case report
A 53-year-old man underwent coronary bypass grafting for coronary artery disease in May 2002. He received a LIMA–LAD anastomosis. In January 2003, he presented with angina on minimal exertion. Angina persisted despite medical therapy. There were no significant findings on physical examination. Electrocardiogram (ECG) did not display any recent ischemic changes. Cardiac enzymes (troponin T, CK, CK-MB) were all negative. Patient relieved stress test-induced angina and depression of the ST segment in leads V4 to V6. In addition, myocardial perfusion scintigraphy (21 mCi Tc-99m stress SPECT) yielded reversible anterolateral wall ischemia. Coronary angiography demonstrated a large patent first intercostal branch and significant reduction in the lumen of the distal LIMA compared to its proximal part, with poor filling of the grafted coronary artery ( Fig. 1 ). This appeared to be the only cause of anginal symptoms in this patient. Therefore, we decided to occlude the intercostal side branch after receiving informed consent of the patient. The internal mammary artery was selectively catheterized with a 6F guiding catheter (Envoy, Cordis Europe NV, Roden, the Netherlands). Through this guiding catheter, a Microcatheter system [Rapid Transit, Cordis Neurovascular (Miami, FL, USA) and microguidewire (Terumo, Radiofocus Guidewire GT, Tokyo, Japan)] was inserted and the intercostal artery was superselectively catheterized. We measured the diameter of the collateral vessel to select occlusion coils size. Afterward, two 0.018″ electrically detachable platinum microcoils (Micrus, CA, USA), 2 and 3 mm in diameter, were introduced through the coaxial catheter and used to occlude this side branches. The coils were either 2 cm long. Angiography after the deployment of the coils showed complete occlusion of the intercostal side branch. There was significant improvement in filling of the internal mammary artery and grafted coronary artery ( Fig. 2 ). The patients’ exercise tolerance improved significantly and findings of stress test-induced angina on ECG disappeared. We used anticoagulation (heparin iv bolus 5000 U and continued with 1000U/h iv infusion) during the occlusion procedure. The patient was subsequently angina-free and is still asymptomatic 2 years after coil embolization.
