Case Report

Alcohol Septal Ablation Through an Anomalous Right Coronary Septal Perforator: First Report and Discussion

David Choi, DO, Joseph Dardano, RPA, Srihari S. Naidu, MD
David Choi, DO, Joseph Dardano, RPA, Srihari S. Naidu, MD
ABSTRACT: Alcohol septal ablation has become an acceptable alternative to surgical myectomy in patients with hypertrophic obstructive cardiomyopathy who meet strict clinical and anatomic criteria. While the first septal perforator arising off the left anterior descending artery is the typical conduit for alcohol septal ablation, patients with hypertrophic cardiomyopathy and severe septal hypertrophy may present with unusual septal perforator anatomy, including anomalous origin. We present the case of a patient in whom the dominant basal septal perforator arose anomalously off the proximal right coronary artery. This anomaly has not previously been reported in patients without obstructive left coronary disease. Successful alcohol septal ablation was performed with the use of myocardial contrast echocardiography and optimum guide catheter and balloon support. Anomalous origin, when encountered, may be utilized successfully for alcohol septal ablation, and should not be considered a contraindication to the procedure.

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J INVASIVE CARDIOL 2009;21:e106–e109 The interventricular septum is normally supplied by septal perforator branches arising from the left anterior descending (LAD) and posterior descending (PDA) arteries. As a result, the hypertrophied basal septum is almost uniformly approached via a first septal perforator arising off the LAD in patients undergoing alcohol septal ablation. Anomalous septal perforators are an uncommon finding. While an anomalous right coronary origin has been described in patients presenting with LAD occlusion or stenosis of the left main coronary artery (LMC),1–3 it has not been described in the absence of obstructive coronary artery disease or in patients with hypertrophic cardiomyopathy (HCM) and basal septal hypertrophy. Furthermore, successful alcohol ablation of a septal artery arising anomalously from the right coronary artery (RCA) has not been previously described. Case Presentation. A 61-year-old male presented with dizziness and dyspnea (New York Heart Association Class III). A dynamic systolic ejection murmur was noted. Exercise treadmill testing was terminated at 3 minutes, as the patient had severe hypotension. His family history was significant for premature sudden cardiac death. Electrocardiography showed normal sinus rhythm at 63 beats per minute with normal axis, voltage criteria for left ventricular hypertrophy, and 1.5 mm ST-segment elevation in leads V1–V3. Echocardiography revealed basal septum thickness of 1.9 cm (Figure 1) and systolic anterior motion of the mitral valve leaflet. The left ventricular outflow tract (LVOT) gradient was 160 mmHg at rest, increasing to > 200 mmHg on provocation. The patient remained symptomatic despite augmentation of beta-blocker therapy, prompting diagnostic cardiac catheterization and alcohol septal ablation. Hemodynamics showed a 10 mmHg resting gradient, which increased to 50 mmHg with the Valsalva maneuver, 200 mmHg with the Brockenbrough maneuver, and over 250 mmHg with combined maneuvers (Figure 2). Left heart catheterization revealed normal coronary arteries without proximal LAD septal perforators. Angiography of the RCA demonstrated an anomalous septal perforator artery arising from the right coronary ostium supplying the basal septum (Figures 3 and 4). Using a 6 Fr Judkins Right guiding catheter, the anomalous septal artery was wired with a 300 cm Asahi Soft coronary wire (Asahi Intecc Co., Ltd., Aichi, Japan). A 2.0 x 6.0 mm OTW Sprinter® angioplasty balloon (Medtronic, Inc., Minneapolis, Minnesota) was inflated in the proximal portion of the anomalous artery. Under myocardial contrast echocardiographic guidance (Figure 5), the anomalous septal artery was infused and shown to be subtending (and confined to) the basal interventricular septum at the point of mitral valve-septal contact. Figure 6 depicts the septal artery and its territory during contrast injection. A dose of 2.5 cc of ethanol was infused over 3 minutes, with the post-infusion angiogram demonstrating complete obliteration of the anomalous septal perforator artery (Figure 7). At the termination of the procedure there was complete resolution of the resting gradient, with a provocable 80 mmHg gradient during combined Valsalva and Brockenbrough maneuvers (Figure 8), indicating a successful procedure (> 50% gradient reduction). The patient was discharged without complication, and remains in NYHA Class I at 6-month follow up. Discussion. Alcohol septal ablation is an effective alternative to surgical myectomy in patients with hypertrophic cardiomyopathy.4 Roughly 90% of patients benefit if they meet strict clinical, echocardiographic and coronary criteria.5,6 The injection of alcohol produces a controlled myocardial infarction with vascular necrosis and absence of platelet-fibrin thrombi, distinguishing it from atherosclerotic infarction.7 Acute stunning of the point of coaptation between the basal septum and the anterior mitral valve leaflet relieves obstruction acutely, followed by myocardial remodeling that maintains benefit over time. Septal anatomy is highly variable, particularly in HCM patients with severe septal hypertrophy. Septal perforators range from single large and branching arteries to multiple arteries of varying size arising from the LAD and/or diagonal vessels. Anomalous septal arteries arising from the proximal RCA are rare, previously seen only in patients with occlusive disease of the left coronary system.1–3 Our case depicts an anomalous septal artery from the RCA in a patient without obstructive coronary disease. Significant septal hypertrophy, and the ischemia that results from elevated intracavitary pressure (increased afterload or wall stress) and reduced myocardial blood supply (impaired coronary vasodilation and myocardial blood flow), as is typically seen in patients with severe HCM and LVOT obstruction, may have prompted development of this anomaly. The lack of a dominant first septal perforator arising from the LAD may have further contributed to the drive for anomalous supply in our patient. Accordingly, an anomalous septal perforator arising off the RCA should be considered in all patients whose left coronary angiography fails to reveal a dominant basal septal perforator. To our knowledge, our case is not only the first reported anomalous right coronary septal artery in the setting of non-occlusive coronary disease, but also the first description of successful alcohol septal ablation in this setting. Alcohol ablation using anomalous septal arteries understandably relies heavily on myocardial contrast echocardiography to document the correct trajectory and lack of remote distribution.8–10 Once confirmed, the alcohol septal ablation procedure proceeds normally. However, as the backup provided by standard RCA guides is lower than that provided by typical left coronary guides, more attention must be placed on optimizing balloon positioning and guide support so as not to infuse ethanol inadvertently into the main trunk of the RCA. An over-the-wire cutting balloon, as previously described, may help optimize balloon stability in such cases.11 In summary, patients with HCM and asymmetric septal hypertrophy oftentimes have unusual septal perforator anatomy, which may include anomalous origin. The current case illustrates an anomalous septal perforator arising off the proximal RCA, in the absence of left coronary obstructive disease. Such an anomaly should be sought whenever dominant left septal perforators are not evident, and may facilitate successful alcohol septal ablation. __________________________ From the Division of Cardiology, Department of Medicine, Winthrop University Hospital, Mineola, New York. The authors report no conflicts of interest regarding the content herein. Manuscript submitted January 7, 2009 and accepted February 25, 2009. Address for correspondence: Srihari S. Naidu, MD, Director, Cardiac Catheterization Laboratory Winthrop University Hospital, 120 Mineola Blvd., Suite 500, Mineola, NY 11501. E-mail: ssnaidu@winthrop.org

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