Septal Sobriety: Aborted Alcohol Septal Ablation for Hypertrophic Cardiomyopathy Secondary to Diffuse Coronary-Cameral Fistulae

Abstract

A 40-year-old male with known hypertrophic cardiomyopathy presented with persistent symptoms of chest pain, dyspnea and syncope, despite good medical therapy. Vitals were normal and physical exam did not reveal any resting murmurs or precordial heaves. But a harsh 2/6 systolic murmur could be auscultated at the right sternal border with Valsalva. 

Echo revealed a 69% ejection fraction and 28-mm-thick septum with signs of left ventricular outflow tract obstruction. Catheterization revealed normal coronaries and confirmed a significant gradient of 135 mmHg after induction of a premature ventricular contraction. After discussing treatment options, the patient opted for percutaneous alcohol septal ablation. However, after balloon isolation of septal perforating arteries and injection of Lipid Microsphere Echo Contrast (which localizes the myocardium for ablation via TEE guidance), the contrast was seen jetting freely from the septum into the ventricular cavities. The phenomenon was observed regardless of the perforator isolated. 

A diagnosis of extensive congenital coronary-cameral fistulae was made and due to concerns of the possible effects of escaping alcohol on the patient’s downstream vasculature and organs, the ablation was aborted and he was referred for surgical myomectomy. Our literature review did not find any cases of coronary-cameral fistulae being documented in this manner. Our novel method allows for real-time conception of flow through the cameral fistulae, without relying on color extrapolation used in traditional echo modalities. 

Introduction 

Coronary-cameral fistulae are a rare condition where a vascular communication arises from one or more coronary arteries which then terminate directly into one of the four cardiac chambers, giving rise to possibly significant left-right or left-left shunting (depending on the terminating chamber). We present the case of a young man with medically refractory obstructive hypertrophic cardiomyopathy who opted for percutaneous intervention in order to avoid a surgical septal reduction. Ironically, during his procedure, he was found to have a rare coronary anomaly (which was captured via a novel imaging technique not previously described in the medical literature), that ultimately rendered his percutaneous correction prohibitive. 

Case report

A 40-year-old male with a history of hypertrophic cardiomyopathy (HCM) diagnosed 5 years ago presented to the cardiology service with persistent dyspnea on exertion, chest pain, dizziness, palpitations, and syncope. His symptoms had progressively worsened recently, despite being on optimal medical therapy with calcium channel blockers and beta-adrenergic blocking agents, with resting heart rates at 40-59 beats per minute. The patient was adopted and therefore had limited knowledge of his biological family’s medical history, including any incidents of sudden cardiac death. On admission, his vital signs were unremarkable and physical exam did not reveal any murmurs or precordial heaves at rest. With the Valsalva maneuver, a harsh II/VI systolic ejection murmur could be auscultated at the right upper sternal border.  

Electrocardiogram showed elevated voltage suggestive of left ventricular (LV) hypertrophy and left axis deviation. Transthoracic echocardiogram (TTE) demonstrated asymmetric left ventricular (LV) hypertrophy with septum thickness of 28 mm. Systolic anterior motion of the mitral valve was present, creating a left ventricular outflow tract (LVOT) gradient of 75 mmHg (Figure 1). The LV ejection fraction was 69%. TTE also demonstrated mild aortic, mitral and tricuspid regurgitation, and mildly increased right ventricular systolic pressures of 38 mmHg.  The patient underwent cardiac catheterization, revealing no evidence of coronary artery disease. The LVOT baseline gradient was 29 mmHg, which increased to 35 mmHg with Valsalva maneuver, and rose to 135 mmHg after inducing a premature ventricular contraction. Part of the discordance between cardiac catheterization and TTE was the emergence of ectopy with deeper insertion of the pigtail into the left ventricular cavity, obscuring the true LVOT gradient. After the procedure, discussions were held with the patient about possible treatment options, including continued medical management, placement of a defibrillator/pacemaker, alcohol septal ablation, or surgical septal myomectomy. After weighing the options, the patient selected to proceed with the percutaneous alcohol septal ablation.  

The patient was taken back to the cardiac catheterization laboratory and a temporary pacemaker was placed in the right ventricle. A Balance Middleweight Wire (BMW) (Abbott Vascular) was passed down the left anterior descending (LAD) artery to the first septal perforator. An Apex 1.5 mm over-the-wire balloon (Boston Scientific) was passed into the septal perforator, inflated, and the wire was removed. Baseline transesophageal echocardiographic (TEE) images were obtained.  An ultrasound contrast agent (Definity, Lantheus Medical Imaging) was injected into the first septal perforator. This caused the area of myocardium supplied by the engaged septal perforator to enhance on the echocardiographic images, thus localizing the myocardium targeted for ablation. However, shortly after injection of the echo contrast agent, jets of contrast were observed emanating from the septal wall into the LV cavity (Figure 2, Video 1). Coronary injection of iodinated radiographic contrast under fluoroscopy indicated proper occlusion of the septal artery without reflux of contrast back into the LAD, yet demonstrated similar contrast extravasation into the LV cavity as that seen with Definity on TEE (although not as visually impressive). The balloon was deflated and the next septal perforator was engaged. An Apex 2.0 x 15 mm balloon (Boston Scientific) was used for septal occlusion. Once again, after injection of the Definity, jets of contrast were observed emanating from the interventricular septum, but this time into the right ventricular cavity (Figure 3). The phenomenon was observed regardless of which septal perforator was isolated. Due to concerns about the possible effects of the alcohol on the patient’s downstream vasculature and organs, the procedure was aborted and the patient was later evaluated for surgical myomectomy. 

Discussion

Alcohol septal ablation was first reported by Sigwart in 1995, as the first non-surgical treatment option for HOCM in a series of 3 patients. He showed temporary occlusion of the first major septal artery through an inflated balloon catheter and absolute alcohol injection produced a localized infarct of hypertrophied part of the septum and reduced the intraventricular pressure gradient significantly.¹ Myocardial contrast echocardiographic guidance improves the success and safety of alcohol septal ablation, modifying the interventional approach in up to 20% of cases.² Commercially available myocardial contrast agents consist of microbubbles of perflutren (octafluoropropane) gas or air encapsulated in a shell of lipid, albumin, or galactose. The difference in acoustic impedance between the gas bubbles (or ethanol) and myocardium generates echocardiographic contrast within the area of injection.The extravasation of echocontrast into this patient’s ventricles after selective engagement of the septal perforators was indicative of severe, diffuse coronary-cameral fistulae — a diagnosis that went undetected on all of his previous echocardiograms. Coronary-cameral fistulae are a rare condition mostly seen as an iatrogenic disorder, usually acquired (ironically, in this case) after surgical septal myomectomy for treatment of hypertrophic obstructive cardiomyopathy.³ Even more rare are natural cameral fistulae, which are congenital anomalies reported in only 0.08-0.3% of patients undergoing diagnostic coronary angiography.⁴

Coronary-cameral fistulae have been associated with complications such as myocardial ischemia secondary to a steal phenomenon, bacterial endocarditis, and sudden cardiac death, all of which may potentially reduce life expectancy. The presence of left-to-right shunting may potentially increase the risk of future right ventricular overload, pulmonary hypertension, and even congestive cardiac failure.⁵ Clinical presentation depends on the hemodynamic significance of the fistula, with angina and exertional dyspnea being most prevalent among symptomatic patients.⁶ However, most patients found to have coronary-cameral fistulae are asymptomatic, with the anomalies being found incidentally during coronary angiography for other clinical reasons.⁷

Once documented, the severity of the fistulae can usually be monitored over time via color Doppler echocardiography. Yet, as seen in the case of our patient, even this can be very subjective and can be easily missed on initial studies, depending on the echo machine configuration, operator skill, and interpreter. Optimal management of coronary-cameral fistulae is mostly unknown secondary to the rarity of its presentation. Patients with focal anomalies that cause large shunting effects may benefit from closure of the shunt. Patients with diffuse or multiple fistulae are normally too complex and are unlikely to be candidates for surgical correction. In these patients, reports have shown successful treatment with optimal long-term medical therapy such as beta blockers.⁸ The diffuse nature of our patient’s fistulae make surgical correction of the shunts implausible. However, it is unlikely that any detrimental effects would ensue from development of any new cameral fistulae as a result of proceeding with surgical myomectomy for treatment of his obstructive hypertrophic cardiomyopathy, given the chronic presence of his congenital fistulae. 

Conclusion

This case serves as a great example of unconventional and unexpected findings that can be encountered during what would otherwise be considered routine cases. And, being familiar with these potential anomalies, and the possible sequelae of your treatment, can make a major difference in the morbidity (or even mortality) outcomes of your patients. Furthermore, our literature review did not reveal any prior cases of coronary-cameral fistulae being documented in this manner. Our novel method allows for an unconventional, yet more physiologically natural, visualization of flow through these coronary-cameral fistulae, all without relying on artificial color extrapolation seen in traditional echo modalities. 

References

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8. Liberthson RR, Sagar K, Berkoben JP, Weintraub RM, Levine FH. Congenital coronary arteriovenous fistula. Report of 13 patients, review of the literature and delineation of management. Circulation. 1979; 59: 849-854.

This article received a double-blind peer review from members of the Cath Lab Digest Editorial Board. 

Disclosure: The authors report no conflicts of interest regarding the content herein.

The authors can be contacted via Dr. Arun Kumar Nagabandi, MBBS, at arunnagabandi@gmail.com