Atresia of the left coronary artery ostium (ALCAO) is one of the rarest congenital coronary anomalies, in which a solitary right coronary artery supplies the entire myocardium. The myocardium may receive additional perfusion via fistulas from hypertensive ventricles [1,2]. Unilateral coronary ostial atresia usually follows complex heart defects as in the presented case with pulmonary atresia causing critical stenosis with an intact ventricle septum and hypertensive right ventricle chamber. Patients with ALCAO and insufficient coronary perfusion may develop variable symptoms including chest pain, fatigue, dyspnea, arrhythmias, syncope, cardiac compromise and sudden cardiac death [3]. In most children with ALCAO the perioperative mortality is high, therefore heart transplant is the viable option (4,5). We present a novel surgical-interventional hybrid alternative for successful restoration of anatomical and physiological coronary circulation complicated by myocardial ischemia due to coronary steal phenomenon.
5. Patient Information
A 12-year-old girl with severe pulmonary valvar stenosis (PVS), atretic left main coronary artery ostium (ALCAO) and a wide fistula between the hypertensive right ventricle (RV) and the left coronary artery received surgical follow-up consultation.
6. Clinical Findings
The child had NYHA class II-III, episodic abdominal pain and exertional dyspnea. Physical examination showed good general condition, regular heart rate of 70 beats/min, loud systolic murmur of 4-5/6 on Levine scale with a thrill over the chest and jugular notch. Blood pressure was 100/60mmHg, respiratory rate 14 breaths/min and SaO2 96% on room air.
7. Timeline
The known heart defect was diagnosed at birth. Neonatal balloon pulmonary valvuloplasty permitted corrective surgery to be postponed. Heart transplant remained a viable option due to high clinical risk status and operation complexity. The patient attended for echocardiography for 12-year follow-up prior to admission to the cardiac surgery department.
8. Diagnostic Assessment
Normal sinus rhythm with right axis deviation and severe right ventricular hypertrophy were found on ECG. Roentgenogram showed cardiomegaly, pulmonary trunk dilatation and right atrium enlargement. TTE visualized 2nd degree tricuspid valve regurgitation with pressure gradient of 138mmHg, and PVS pressure gradient of 148mmHg. Hemodynamic studies recorded increased central venous (12mmHg), LV end-diastolic (15mmHg) and suprasystemic RV pressures (127/15mmHg).
Angiographic studies illustrated wide RCA (5mm) and atretic ostium of the LMCA (Figure 1, Supplemental Video1). Right ventriculography outlined severe pulmonary valvar stenosis with dome-shaped valve leaflets and post-stenotic pulmonary trunk dilatation. Furthermore, selective fistula angiography and 3D rendered Computed Tomography depicted ALCAO and a wide coronary fistula emerging from the hypertrophic RV (Figures 2, 3; Supplemental Video 2, 3). The fistula orifice sat superficially in the anterior interventricular groove. Multiple proximal and distal converging collateral anastomoses were present between the LMCA and RCA. The LMCA divided into the left anterior descending artery (LAD) and the circumflex artery (CX).
9. Therapeutic Intervention
The patient was qualified for LMCA ostium reconstruction and simultaneous interventional fistula embolization. Sternotomy with cross-clamped aorta and cannulated caval veins under 24°C hypothermia on cardiopulmonary bypass supported the patient. The RCA cardioplegic solution infusion sustained electromechanical quiescence to asystole. Epicardial fat meant the fistula was not visible. The ascending aorta, bulb and proximal LMCA segment were precisely dissected. The ostium was atretic due to a fibrous diaphragm which was excised, and the artery reconstructed with a Biointegral patch. Next, a RVOT infundibulectomy was undertaken with pulmonary commissurotomy and partial resection of the dysplastic leaflets. The now reconstructed and patent LMCA ostium provided a conduit for a multipurpose 5-F catheter over a 0.025-inch hydrophilic steerable guidewire. The fistula branches were implanted with two 6mm diameter Amplatzer Vascular Plugs II (St. Jude Medical, St Paul, MN). Intraoperative epicardial ECHO confirmed antegrade LMCA flow, normal myocardial contractility, and minor fistula leak. The cross-clamp was released and normal sinus rhythm without ischemic ECG changes emerged upon myocardial reperfusion. Post-operative hemodynamic catheterization revealed high RV systolic and diastolic pressures (60/25mmHg), LVEDP (90/26mmHg), central venous pressure (25mmHg), pulmonary venous hypertension (mean 30mmHg) with increased pulmonary flow. Residual fistula leaks (Figure 4, Supplemental Video 4) required interventional endovascular embolization using multiple occluders which were redelivered via LMCA without sequalae (Figure 5, Supplemental Video 5).
10. Follow-up and Outcomes
At 2-year follow-up the girl was asymptomatic on pharmacotherapy (metoprolol and aspirin) with good exercise tolerance (NYHA II). Resting ECG showed normal sinus rhythm without symptoms of ischemia while 2DE revealed good EF (50%) and sealed fistula.