Introduction
Ventriculocoronary connections are uncommon congenital abnormalities associated with hypoplastic left heart syndrome. Large ventriculocoronary connections may impact post-Norwood recovery and survival in hypoplastic left heart patients, possibly meriting closure. Reference Vida, Bacha, Larrazabal and Gauvreau1 We report a full-term male born with mitral stenosis/aortic stenosis subtype hypoplastic left heart and a large ventriculocoronary connection managed without intervention.
Case presentation
A 2.9-kg term infant was born with prenatally diagnosed hypoplastic left heart. At birth, he was well perfused with initial saturations above 95% on room air at 5 minutes of life. Bedside echocardiogram demonstrated a hypoplastic left ventricle with an intact ventricular septum, a 2.5 mm diminutive ascending aorta, 4.6 mm transverse arch, mitral stenosis, and critical aortic stenosis with trivial prograde flow crossing the aortic annulus. The echocardiogram further demonstrated a normal right coronary artery and a dilated left main coronary artery with a large ventriculocoronary connection between the left ventricle and left main coronary artery (Figure 1). Colour Doppler demonstrated bidirectional flow through the fistula and the proximal left coronary artery (Figure 2). The atrial septal defect measured 3 mmHg with an 8 mmHg inter-atrial gradient. The patient started prostaglandin infusion for stabilisation prior to surgery.
Figure 1. Transthoracic echocardiogram apical 4 chamber view with colored Doppler comparison showing a coronary fistula with bidirectional antegrade and retrograde flow in the left ventricle. CF = Coronary fistula; LV = Left ventricle; RV = Right ventricle.
Figure 2. Continuous wave Doppler across the coronary fistula showing bidirectional flow. Retrograde peak velocity is significantly greater than antegrade peak velocity.
On day two, he underwent Norwood stage I palliation with placement of 5 mm Sano shunt. His intraoperative course was largely uncomplicated, though there was a short episode of ventricular tachycardia after deep hypothermia induction. After separation from cardiopulmonary bypass, severe right ventricular dysfunction was visible both by transesophageal echocardiogram and by direct observation. Milrinone, low-dose dopamine, and moderate-dose epinephrine were initiated with clinical improvement. He was transferred to the ICU with an open chest.
Following transfer, he had significant low-cardiac output syndrome, with a peak lactate over 20 mmol/L, requiring escalation to vasopressin and dopamine. At this time, his interdisciplinary team discussed the utility of surgical occlusion of the fistula but decided against it due to the risk of reoperation. With optimised medical therapy, he had gradual recovery, with chest closure on post-operative day 4 and extubation on day 21. He was discharged on day 47. Echocardiogram displayed normalised systemic ventricular function, mild tricuspid regurgitation, and persistence of the ventriculocoronary connection with bidirectional flow in the left ventricle. No further ventricular dysrhythmias were appreciated during his hospitalisation.
His pre-operative catheterisation demonstrated favourable haemodynamics for progression to stage II surgery, and echocardiogram showed no change in ventricular function. At 6 months, he successfully underwent a bidirectional Glenn procedure. The post-operative transesophageal echocardiogram noted good ventricular function and adequate flow through the cavopulmonary conduit. The ventriculocoronary could still be seen with bidirectional flow, but otherwise there was no evidence of ischaemia. Now 2 years old, the patient is doing well clinically with mild tricuspid regurgitation. On his most recent echocardiograms, the ventriculocoronary connection cannot be redemonstrated.
Discussion
Hypoplastic left heart accounts for a small proportion of CHDs and is classified into three morphological categories: mitral atresia/aortic atresia, mitral stenosis/aortic atresia, and mitral stenosis/aortic stenosis. Reference Baffa, Chen, Guttenberg, Norwood and Weinberg2–Reference Nathan, Williamson, Mayer, Bacha and Juraszek4 Ventriculocoronary connections detectable by echocardiography have been described in about 15% of hypoplastic left heart cases and can lead to higher mortality and morbidity after stage I palliation. Reference Vida, Bacha, Larrazabal and Gauvreau1,Reference Sathanandam, Cui and Nguyen5 When examined microscopically in post-mortem specimens, small connections are ubiquitous in cases with patent inflow and obstructed outflow. Reference O’Connor, Cash, Cottrill, Johnson and Noonan6 Although ventriculocoronary connections form most frequently in mitral stenosis/aortic atresia phenotypes, they rarely develop in mitral stenosis/aortic stenosis phenotype, as seen in our case. We hypothesise that embryological sinusoids persisted in our patient to unload a left ventricle with suprasystemic pressure and an intact intraventricular septum. Reference Baffa, Chen, Guttenberg, Norwood and Weinberg2 As demonstrated by angiographic studies, these connections demonstrate retrograde ventricle-to-right-coronarysystolic flow and antegrade diastolic flow into the left ventricle. Reference Nathan, Williamson, Mayer, Bacha and Juraszek4,Reference Sathanandam, Cui and Nguyen5,Reference Hansen, Uebing, Scheewe, Kramer and Fischer7 While larger coronary fistulas carry the potential to deliver collateral myocardial perfusion during systole, they also cause diastolic run-off with consequent steal of coronary blood flow. Reference Baffa, Chen, Guttenberg, Norwood and Weinberg2
By this mechanism, ventriculocoronary connections can complicate staged palliation as they can hinder myocardial perfusion during bypass, resulting in right ventricular ischaemic injury and low cardiac output syndrome. Reference Vida, Bacha, Larrazabal and Gauvreau1,Reference Stephens, Gupta, Bleiweis, Backer, Anderson and Spicer8 Procedures that avoid cardiopulmonary bypass, such as hybrid stage I or primary transplant, may benefit patients with large ventriculocoronary connections; however, benefits have not yet been proven. Reference Sathanandam, Cui and Nguyen5 Continuous cold blood cardioplegia may also mitigate complications. Reference Polimenakos, Sathanandam, Husayni, El Zein, Roberson and Ilbawi9 These alternative strategies were considered initially, but they did not provide any clear advantage over the Sano. Intervention on the fistula at the time of the stage I palliation was also considered but deemed too high risk given the similarly unproven benefits of this technique, increased bypass time, and concern for disruption of possible collateral myocardial perfusion during systole. Reference Baffa, Chen, Guttenberg, Norwood and Weinberg2
During the post-operative period, emergent surgical ligation and catheter-guided occlusion with coils were discussed as options to eliminate the ventriculocoronary connection but not pursued given the high risk of reoperation and the gradual stabilisation of the patient. Reference Sathanandam, Cui and Nguyen5,Reference Baş and Alkara10 Ultimately, medical management, with the goal of balancing systemic and pulmonary flow, led to progressive right ventricular recovery. At the time of stage 2 palliation, despite surgeon preference for hemi-Fontan procedures, we elected for bidirectional Glenn procedure. Glenn afforded the benefit of avoiding cardiopulmonary bypass and compression of the left ventricular cavity.
Our case illustrates that medical management can result in good outcomes for hypoplastic left heart patients with large ventriculocoronary connections, even in cases with post-operative myocardial injury. Our research and case also both suggest that, if ventriculocoronary connections are to be intervened upon at any point, it should not be during a period of post-operative myocardial dysfunction . Reference Sathanandam, Cui and Nguyen5,Reference Baş and Alkara10
Conclusion
In hypoplastic left heart with mitral stenosis/aortic stenosis subtype, large haemodynamically significant ventriculocoronary connections are rare but may lead to complications after cardiopulmonary bypass surgery. As shown in this case, hypoplastic left heart patients with ventriculocoronary connections can be managed without fistula occlusion or ligation, though they may manifest significant early post-operative dysfunction. Use of the Sano shunt and bidirectional Glenn procedure may be advantageous in comparison to other methods for regulating pulmonary blood flow and minimising diastolic coronary steal. Further research into criteria for ligation of large ventriculocoronary connections at the same time as stage I palliation is needed.
Acknowledgements
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Financial support
This research received no specific grant from any funding agency, commercial or not-for-profit sectors.
Competing interests
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