Abstract
A 54 year old man with hypertrophic cardiomyopathy was evaluated for alcohol septal ablation. However there were no sizeable septal branches from the left anterior descending artery supplying the basal septum. He was found to have a rare variant, the descending septal branch from ostial right coronary artery and underwent ablation through the same. We describe our case and the relevant literature available for use of this anatomical variant in alcohol septal ablation.
Highlights
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Descending septal branch (Bonapace’s branch), arising from the proximal right coronary artery is a very rare variant and supplies the basal interventricular septum.
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When present, this is a likely target for alcohol septal ablation in patients with hypertrophic cardiomyopathy.
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Overlooking this branch may lead to failure of alcohol septal ablation.
1
Introduction
Hypertrophic cardiomyopathy (HCM) is an inherited genetic disorder affecting the cardiac sarcomere, with an estimated phenotypic prevalence of 0.2% . Septal reduction therapy is recommended for severely symptomatic patients which are refractory to medical therapy . Alcohol septal ablation (ASA) is considered a viable alternative to surgical myectomy, either in patients with high surgical risk or for patient preference in high volume centers in the United States while the European guidelines do not make a distinction between the two approaches . We describe a case where ASA was performed via the descending septal branch of the right coronary artery, a rare anatomical variant and summarize literature about non left anterior descending (LAD) artery targets for ASA.
2
Case report
A 54 year old male patient with HCM and atrial fibrillation was referred to our institution. He had disabling New York Heart Association class III dyspnea on exertion despite treatment with beta blockers and calcium channel blockers. An implantable cardioverter defibrillator had been implanted because of history of non-sustained ventricular tachycardia and high risk features on stress testing. A trans-thoracic echocardiogram revealed asymmetric septal hypertrophy with the basal anterior septum measuring 2.5 cm and systolic anterior motion of the anterior mitral leaflet ( Fig. 1 A, B, C ). He thus underwent cardiac catheterization with an intention to pursue alcohol septal ablation (ASA). A resting gradient of 16 mmHg was measured with hemodynamic catheterization which increased to 80 mmHg in the beat following an induced premature ventricular contraction (PVC) ( Fig. 1 D). Another approach which may increase reproducibility of induced gradients, while avoiding the risk of catheter entrapment and a falsely elevated gradient is to use an Isoproterenol or Dobutamine infusion. Angiogram of left coronary artery did not reveal a first septal unit which supplied the basal septum ( Fig. 1 E, F). However right coronary angiogram revealed a descending septal artery (Bonapace’s branch) arising from the ostium ( Fig. 1 G, H). Hence we wired the vessel using a 6 Fr Judkins Right 4 guide catheter (Cordis Corporation, Miami Lakes, Florida, USA) and a 0.014′ Hi Torque Whisper MS wire (Abbott Vascular, Santa Clara, California, USA) and inflated a 1.2 × 8 mm over-the-wire Mini Trek balloon (Abbott Vascular, Santa Clara, California, USA) in the vessel ( Fig. 1 I). Agitated contrast injected through the balloon selectively enhanced the basal septum ( Fig. 1 J, K). Hence 2.5 cm 3 of pure alcohol was injected in this branch resulting in abolition of gradient at rest and decrease in post PVC gradient to 8 mmHg ( Fig. 1 L).
2
Case report
A 54 year old male patient with HCM and atrial fibrillation was referred to our institution. He had disabling New York Heart Association class III dyspnea on exertion despite treatment with beta blockers and calcium channel blockers. An implantable cardioverter defibrillator had been implanted because of history of non-sustained ventricular tachycardia and high risk features on stress testing. A trans-thoracic echocardiogram revealed asymmetric septal hypertrophy with the basal anterior septum measuring 2.5 cm and systolic anterior motion of the anterior mitral leaflet ( Fig. 1 A, B, C ). He thus underwent cardiac catheterization with an intention to pursue alcohol septal ablation (ASA). A resting gradient of 16 mmHg was measured with hemodynamic catheterization which increased to 80 mmHg in the beat following an induced premature ventricular contraction (PVC) ( Fig. 1 D). Another approach which may increase reproducibility of induced gradients, while avoiding the risk of catheter entrapment and a falsely elevated gradient is to use an Isoproterenol or Dobutamine infusion. Angiogram of left coronary artery did not reveal a first septal unit which supplied the basal septum ( Fig. 1 E, F). However right coronary angiogram revealed a descending septal artery (Bonapace’s branch) arising from the ostium ( Fig. 1 G, H). Hence we wired the vessel using a 6 Fr Judkins Right 4 guide catheter (Cordis Corporation, Miami Lakes, Florida, USA) and a 0.014′ Hi Torque Whisper MS wire (Abbott Vascular, Santa Clara, California, USA) and inflated a 1.2 × 8 mm over-the-wire Mini Trek balloon (Abbott Vascular, Santa Clara, California, USA) in the vessel ( Fig. 1 I). Agitated contrast injected through the balloon selectively enhanced the basal septum ( Fig. 1 J, K). Hence 2.5 cm 3 of pure alcohol was injected in this branch resulting in abolition of gradient at rest and decrease in post PVC gradient to 8 mmHg ( Fig. 1 L).
