Predictors of Success of Biventricular Repair of Infants with Multiple Left Heart Obstructive Lesions

Several factors, including left (LV) and right (RV) ventricle diastolic longitudinal ratio, may offer insights into the likelihood of success of biventricular (2V) repair in infants with multiple left heart obstructive lesions, according to a study recently published in Congenital Heart Disease. The Cleveland Clinic Children’s study mined the surgical histories of 19 infant patients to discover previously ill-defined echocardiographic and anatomic predictors of success.

Neonates with two or more left heart obstructive lesions can be surgically repaired using a single-ventricle (1V) palliation or biventricular (2V) repair. The initial decision is critical, and decision making regarding the best route for individual babies has been difficult.

“These patients present with a wide spectrum of anatomy and symptoms, and surgical decision making is difficult and complex,” says Francine Erenberg, MD, senior author of the study and Director of the Pediatric Cardiology Fellowship Program at Cleveland Clinic Children’s. “Right now, there are no guidelines to determine the best approach. Our study is a first step toward exploring what those guidelines might include.”

Study design

This retrospective study identified 19 patients with multiple left heart obstructive lesions with no prior interventions and no history of aortic or mitral valve (MV) atresia or critical aortic stenosis. Five of those patients had had 1V palliation, and the remaining 14 had undergone 2V repair. In the 2V group, surgical procedures and approaches included: simple coarctation repair (N = 5), complex coarctation/arch reconstruction with or without septal defect closure (N = 6), hybrid stage 1 (N = 2) and none (N = 1).

A single pediatric cardiologist reviewed initial echocardiograms for mitral, aortic and tricuspid valve annulus size, and LV and RV diastolic longitudinal dimensions. The presence of a ventricular septal defect (VSD), coarctation and valve morphology were also assessed. The researchers measured clinical outcomes as successful 2V repair, any postoperative morbidity and need for repeat interventions or surgeries. Takedown to 1V physiology, need for transplantation or death were criteria for failed 2V repair. Patients were followed for three years.

Predictors of success

Of the 2V patients, three required intervention within the first three months, but no major morbidities (need for reoperation within 30 days, ECMO dependence, stroke) occurred. All of the patients treated with the 1V pathway had successful Glenn procedures. Anatomic factors identified in previous studies as risk factors for 2V failure, including moderate to large VSD, unicuspid aortic valve and MV annulus, were not found to be statistically significant in this study.

Researchers noted several interesting differences between the 1V and 2V groups. “The single ventricle patients had significantly smaller aortic valve annuli, mitral/tricuspid valve ratios and z scores,” says Rukmini Komarlu, MD, coauthor and staff in the Center for Pediatric and Congenital Heart Diseases at Cleveland Clinic Children’s. “There was also a significant difference in LV/RV diastolic longitudinal ratios.

“Others have studied these same markers in the past, with varying results, and some institutions rely on one variable more than others to make surgical decisions. Our point here is that the data do not support isolating one piece of the puzzle or using a mathematical formula to get to an answer, but rather to tailor the approach using all the pieces of the puzzle.”

Patients treated with a 2V approach had excellent short- and mid-term results, though many still required reintervention. No patients required MV intervention although over one-third had a parachute MV, a condition previously associated with higher risk in 2V repair. None required conversion to single ventricular pathway.

No easy answers

The management of neonates with multiple left heart obstructive lesions remains complex. “While I think our study provides some important insights, namely supporting the use of a multifactorial method of risk assessment, there are no easy answers,” says Dr. Erenberg. “We have also transitioned our study from short-term retrospective to long-term prospective follow up, as we continue to follow these patients as they grow. We hope that over time, larger, longer studies will help inform best practices in this unique patient population.”