TITLE: Novel Management Strategy for Coronary Steal Syndrome: Case Report of Occlusion of a LIMA Graft Side Branch with a Combination of Drug-Eluting and Covered-Stent Deployment
From the Department of Interventional Cardiology, Cork University Hospital, Wilton, Cork, Ireland. The authors report no conflicts of interest regarding the content herein. Manuscript submitted April 28, 2009, provisional acceptance given May 18, 2009, and final version accepted June 12, 2009. Address for correspondence: Brian G. Hynes, MD, Department of Interventional Cardiology, Cork University Hospital, Wilton, Cork, Ireland. E-mail address: email@example.com
ABSTRACT: We report a novel percutaneous therapeutic approach to the management of suspected coronary artery steal syndrome resulting from a large side branch of the left internal mammary artery bypass graft, using a combination of coated and drug-eluting stents. We demonstrate the feasibility and long-term efficacy of this strategy in a case report.
J INVASIVE CARDIOL 2009;21:E218–E220 Key words: coronary steal syndrome; left internal mammary artery graft; percutaneous coronary intervention The left internal mammary or thoracic arterial (LIMA) graft confers substantial advantages in terms of long-term patency and survival benefit in patients undergoing coronary artery bypass grafting surgery (CABG).1 Almost 10% of LIMA grafts may possess large side branches.2 The ability of a large left internal mammary arterial graft side branch to induce a true myocardial steal syndrome remains controversial. A number of case reports document successful attenuation of anginal symptoms following termination of blood flow in the culprit side branch.3–6 However the physiological reasoning behind this category of myocardial steal together with the hemodynamic implications of LIMA side-branch occlusion have been questioned.7–9 Furthermore, it has been suggested that true blood-flow diversion from the targeted coronary circulation in the presence of a LIMA side branch may occur only when there is coexisting angiographic stenosis (≥ 80%) in the subclavian artery.10,11 More recently, the case in favor of LIMA side-branch occlusion has been advanced by demonstration of myocardial ischemia reversal with termination of side-branch patency.12,13 We report a novel approach to LIMA side-branch occlusion, and demonstrate continued LIMA graft patency after a 2-year follow-up period. Case Presentation. In January 2007 a 60-year-old male was referred for coronary angiography and graft studies following a 2-week history of chest pain consistent with crescendo angina. On admission he had Canadian Cardiovascular Scale Class 3 angina. He had previously undergone three-vessel CABG 13 years prior to presentation. In addition, he had dyslipidemia and mild chronic obstructive airways disease. Diagnostic coronary angiography performed via the right femoral artery demonstrated severe native-vessel disease in the proximal right, left circumflex, and left anterior descending (LAD) coronary arteries. The saphenous vein graft (SVG) to the circumflex marginal system was occluded at its origin. The SVG to the distal RCA was severely and diffusely diseased throughout. The LIMA to the distal LAD had undergone subtotal occlusion in the 5 days between the initial diagnostic angiogram performed at the referring institution and the current study (Figure 1). Given the large caliber of the LIMA side branch (Figure 1), it was felt that this may have been a contributing factor in the relatively poor LIMA-LAD graft development and LAD territory ischemia. Following consultation with the patient and a cardiothoracic surgeon, the decision was taken to attempt side-branch occlusion with subsequent angioplasty and stenting to the LIMA-LAD graft insertion site. The patient had been adequately pretreated with dual antiplatelet therapy. A total of 8,000 units of unfractionated heparin were administered intra-arterially. The origin of the LIMA graft was selectively engaged using a 6 French (Fr) IMA guide catheter and a PT Graphix Intermediate 0.014 inch guidewire (Boston Scientific Corp., Natick, Massacusetts) was advanced beyond the origin of the LIMA side branch. Under fluoroscopic guidance, a 3.0 x 12 mm polytetrafluoroethylene (PTFE)-covered stent (Jostent, Abbott Vascular, Redwood City, California) was advanced into the LIMA (Figure 2) and deployed at 12 atmospheres (atm) of pressure, ensuring complete occlusion of the side branch (Figure 3A). Re-check angiography suggested an edge dissection just distal to the deployed covered stent. In addition the proximal end of the stent appeared to be undersized. Two Xience V everolimus-eluting stents (Abbott Vascular), a 3.5 x 15 mm and a 3.0 x 23 mm, were then deployed at 14 atm to cover the proximally and distally to the Jostent (Figure 3B). The stenosis at the LIMA-LAD insertion site was then intervened upon with successful deployment of a 2.5 x 18 mm Xience V stent to 14 atm. This led to an immediate increase in flow of contrast to the distal graft and LAD. Finall,y a 2.5 x 18 mm Xience V was deployed following inflation to 14 atm at the stenosis beyond the graft insertion point in the native artery. An excellent final angiographic result was obtained (Figures 4 A–C), and the femoral arteriotomy site was sealed with a standard 6 Fr Angio-Seal closure device (St. Jude Medical, Inc., St. Paul, Minnesota). After the procedure the patient had a significant reduction in his anginal symptoms and a greatly increased exercise tolerance. In February 2009 the patient underwent repeat coronary angiography after an episode of suspected angina. This demonstrated widely patent proximal and distal LIMA stents with complete occlusion of the LIMA side branch. There was mild in-stent restenosis evident in the proximally placed LIMA stents (Figures 5A and B). There was little progression of atherosclerotic disease elsewhere, and the patient was managed by optimization of his anti-anginal and secondary preventative medications. Discussion. In this case report we discuss the technical feasibility of LIMA side-branch occlusion using a covered-stent system. In addition we demonstrate 2-year patency following immediate drug-eluting stent (DES) deployment within the PTFE-covered stent. We elected to provisionally cover the Jostent with a DES in a bid to reduce the risk of restenosis after an edge dissection became apparent following covered-stent deployment. This newer-generation everolimus-eluting stent has been shown to be particularly useful in the treatment of bare-metal stent (BMS) in-stent restenosis.14 Higher rates of neointimal proliferation have been reported with the use of PTFE stent systems,15 though restenosis rates were comparable with BMS in a randomized study of SVG intervention.16 The occlusion of a LIMA side branch using this approach offers an alternative to other available percutaneous strategies such as coil embolization5,17 and nitinol expanding devices,13 or indeed surgical ligation.18 The successful utilization of microcoils to occlude the LIMA side branch requires adequate sizing and careful delivery to avoid trauma to the LIMA itself.19 We have demonstrated the technical feasibility and long-term patency of this approach, which may avoid some of the complications associated with coil embolization. Potential disadvantages of this approach include the higher costs associated particularly with DES implantation and concerns regarding the risk of late acute stent thrombosis.20 Conclusion. The combination of a PTFE-covered stent and DES may provide an alternative strategy to LIMA side-branch occlusion in patients with suspected coronary steal syndrome.