The importance of age and weight on cavopulmonary shunt (stage II) outcomes after the Norwood procedure: Planned versus unplanned surgery

Objective: The study objective was to evaluate the outcomes of the cavopulmonary shunt after the Norwood procedure with a particular focus on age, weight, and whether surgery was planned or expedited by clinical findings. Methods: We studied 297 consecutive patients with hypoplastic left heart syndrome undergoing the cavopulmonary shunt operation between 2002 and 2014. All patients underwent the Norwood procedure with a right ventricle to pulmonary artery conduit. Unplanned surgery was any situation in which surgery was expedited because of refractory desaturation, angiographic findings, or failure to discharge. Results: There were 222 planned and 75 unplanned procedures. Planned surgery was performed at median of 5.4 (4.6-6.3) months compared with 3.9 (3.3-5.0) months for the unplanned group (P <. 001). Early mortality was 1.3% in the planned group compared with 5.3% in the unplanned group (P = .07). At 5 and 10 years, survival was significantly worse in the unplanned group (73% vs 85%, P = .03). On multivariable analysis, atrioventricular valve regurgitation, the need for atrioventricular valve repair, and impaired ventricular function (graded composite variable) were the predominant risk factors (hazard ratio [HR], 7.49), with an incremental risk within these 3 variables. The planned versus unplanned nature of the surgery was less significant (HR, 1.75) because it was eclipsed by ventricular function and tricuspid intervention. Additional factors were aortic atresia/mitral atresia subgroup (HR, 2.07) and somatic growth (z-score weight) at the time of surgery (HR, 0.60 for z-score change from -2.54 to -1.16). Age and weight at surgery were not significant risk factors for survival. Interstage interventions on the aortic arch or right ventricle to pulmonary artery conduit did not adversely influence outcomes. Conclusions: The ventricular function, atrioventricular valve regurgitation, and need for tricuspid intervention were the primary risk factors for survival after the cavopulmonary shunt operation. Although unplanned surgery is associated with poor outcomes, this is related to the primary risk factors and not the timing or age of the patient. Somatic growth also has a significant influence on survival. Thus, an earlier cavopulmonary shunt operation is safe in infants who are thriving, but those with poor weight gain are at higher risk.