Critical left ventricular outflow tract obstruction: The disproportionate impact of biventricular repair in borderline cases

Abstract

Inappropriate pursuit of biventricular repair in borderline candidates is more frequent and more consequential in survival terms than is inappropriate pursuit of univentricular repair. Use of the univentricular survival advantage tool will help identify infants for whom univentricular repair may be a better choice than attempting biventricular repair.

Hybrid Procedure in Neonatal Critical Aortic Stenosis and Borderline Left Heart: Buying Time for Left Heart Growth

“…In a comprehensive review Corno identified risk factors such as quantitative measurements of left ventricular enddiastolic dimensions, aortic and mitral valve orifices indexed for body surface area (Corno, 2005). Associated abnormalities such as younger age, endocardial fibroelastosis, non-compaction of the left ventricle, aortic coarctation, mitral valve abnormalities and pulmonary hypertension are also important risk factors to be considered (Hickey et al, 2007). In the end, both objective measurements and clinical judgment need to be taken into account when deciding what is considered a borderline left ventricle.…”

“…However, in true borderline cases, this early decision proves to be difficult due to lack of guidelines with clear -cut predictability. Several scoring systems such as the Rhodes score (Rhodes et al, 1991), Colan score (Colan et al, 2006) and the Univentricular Repair Survival Advantage Tool (Hickey et al, 2007) exist to predict the optimal type of repair. These scoring systems use several left ventricular parameters in an equation, the result of which above or below a given cut-off value generates the predicted most favourable treatment strategy.…”

“…In the Colan score, the equation is based on body surface area, aortic annulus z-score, left ventricle to heart long axis ratio and degree of endocardial fibroelastosis (Colan et al, 2006). The Univentricular Repair Survival Advantage Tool is based on morphologic, functional and pathologic information; the exact equation is not published but the score can be calculated at the freely accessible Congenital Heart Surgeons' Society website www.chss.org (Hickey et al, 2007). A recent small series, however, demonstrated that the results of the aforementioned scoring systems never provided unanimous recommendations regarding the optimal type of repair for the individual patient with borderline left heart (Davis et al, 2011).…”

“…When a univentricular strategy is followed from the neonatal phase, conversion to biventricular physiology may no longer be an option or may be extremely difficult. Risk factors for increased mortality after univentricular repair consist of tricuspid valve regurgitation, presence of a large ventricular septal defect and smaller indexed dominant ventricular length (Hickey et al, 2007). Despite major improvement in survival rates of the Norwood stage I procedure, infants undergoing this procedure still face a mortality risk of 10-30%, depending on risk factors and the experience level of the team (Bacha, 2006, Stasik et al, 2006.…”

“…When a biventricular strategy is chosen early but eventually fails, usually due to low cardiac output or pulmonary hypertension, this can lead to death of the patient; otherwise conversion to a univentricular circulation is associated with markedly increased risk (Davis et al, 2011, Pizarro et al, 2009). Decreased survival rates after biventricular repair are found in patients with small left ventricular outflow tract size, small aortic arch size, presence of endocardial fibroelastosis or left ventricular dysfunction (Hickey et al, 2007). Inappropriate pursuit of biventricular repair occurs more often and entails poorer survival rates as compared to inappropriate univentricular repair (Hickey et al, 2007).…”