Early experience with a modified Norwood procedure using right ventricle to pulmonary artery conduit

BACKGROUND: A recent modification to the Norwood procedure involves the use of a right-ventricle (RV) to pulmonary artery (PA) conduit to provide pulmonary blood flow for patients with hypoplastic left heart syndrome (HLHS). This modification is thought to provide more stable hemodynamics by avoiding the diastolic "run-off" that occurs with a Blalock-Taussig shunt. METHODS: We reviewed our experience with the first 11 patients undergoing the RV-PA conduit modification of the Norwood operation and compared their outcomes with those of the preceding 22 patients who underwent a conventional Norwood procedure. RESULTS: Between July 1999 and March 2002, 33 patients with HLHS underwent the Norwood procedure at a median age of 5 days (range 1 to 31 days). Aortic atresia was present in 28 (85%). No significant difference was noted between the RV-PA (n = 11) and conventional Norwood (n = 22) groups with respect to measures of morbidity such as duration of mechanical ventilation or hospital stay. Patients who underwent the conventional Norwood procedure did have significantly lower diastolic blood pressure in the early postoperative period (38.4 +/- 4.4 mm Hg versus 49.5 +/- 4.3 mm Hg, p = 0.001). The operative and 1-year survival rates were 81% and 81%, respectively, for patients with the RV-PA modification, which was not significantly different from those of patients who underwent the conventional procedure, 81% and 73% (p = 1.00 and p = 0.36). Two patients developed a pseudoaneurysm of the RV infundibulum after placement of RV-PA conduit. Four sudden deaths occurred after hospital discharge, all occurring in the conventional Norwood group. CONCLUSIONS: The RV-PA conduit modification of the Norwood procedure results in excellent early survival. By avoiding low diastolic blood pressure this modification may provide superior perfusion to the coronary vascular bed and potentially reduce the risk of sudden unexpected death.     

Comparison of right ventricle to pulmonary artery conduit and modified Blalock-Taussig shunt hemodynamics after the Norwood operation

The Norwood procedure remains one of the highest-risk operations in congenital heart surgery. A significant contributor to this risk is thought to be the diastolic run-off into the modified Blalock-Taussig shunt (MBTS). In an effort to eliminate this risk, several groups have begun to utilize a right ventricle to pulmonary artery conduit (RVPAC), which decreases this diastolic “steal” of coronary blood flow. Whereas initial results with the RVPAC are encouraging, the postulated hemodynamic advantages are unproven. This case illustrates the positive hemodynamic changes by echocardiography after the replacement of a MBTS with a RVPAC in a patient after a Norwood procedure.     

Rudimentary right ventricle to pulmonary artery shunt in the Norwood procedure

We describe here successful palliative repair of tricuspid atresia, hypoplastic right ventricle, transposition of the great arteries, and hypoplastic aortic arch in a neonate. The repair consisted of the Norwood procedure with a rudimentary right ventricle to pulmonary artery shunt, which was located on the right side of a neo-aorta. This procedure could be a useful adjunct to avoid left ventriculotomy and its subsequent dysfunction.     

Proximal conduit obstruction after Sano modified Norwood procedure

Sano and colleagues recently described a modification of first stage palliation for hypoplastic left heart syndrome utilizing a right ventricle to pulmonary artery conduit. Preliminary results are favorable, but experience with this technique is limited. We report a case of sudden death due to obstruction of the proximal conduit by fibrointimal hyperplasia. This case of lethal conduit obstruction presented 3 months after initial palliation. Early cardiac catheterization and second stage palliation may be necessary to minimize the risk of such adverse events after the Sano modification.     

Long-term outcome after right ventricle to pulmonary artery conduit surgery and reintervention

Background. Reconstruction of the right ventricular outflow tract with a conduit is an established surgical procedure in congenital heart disease and reinterventions are common. Objective. An increasing number of patients have a conduit, but there are few population-based studies of long-term outcomes after conduit surgery, reoperations, and transcatheter pulmonary valve replacement. Methods. In April 2015, all adult patients with a conduit were identified in the Swedish National Registry for Congenital Heart Disease (SWEDCON). Data on patients who died before age of 16 years are not included in the registry and thus not included in the study. Results. We found 574 patients with a mean age 36.1 years. The largest proportion had tetralogy of Fallot (45%). In total there were 762 operations and 50 transcatheter pulmonary valve replacements. Mean age at first conduit operation was 20.2 years. Long-term survival up to 48 years including perioperative mortality (<1%) was 93% at 20 years. The most common cause of death was cardiac-related. Higher age at first conduit operation was associated with increased mortality risk. Reintervention-free survival was 77% and 54% at 10 and 20 years, respectively. Conduit reinterventions were common. Ten-year reintervention-free survival after first conduit reintervention (n?=?176) was significantly lower than after first conduit operation (70% vs 77% p?=?.04). Higher age at first conduit operation was associated with a reduced risk of reintervention, whereas male sex and complex malformations were associated with increased risk of reintervention. Conclusions. The mortality of repeated conduit reinterventions is low. The need for reintervention of conduits is considerable, and reintervention-free survival after the first conduit reintervention is poorer than after first conduit implantation. The findings in this study only applies for patients reaching 16 years of age.     

Contegra bovine jugular vein right ventricle to pulmonary artery conduit in Ross procedure

BACKGROUND: In the Ross procedure a valved conduit, most commonly pulmonary or aortic homograft, is used in place of autotransplanted pulmonary valve. Increasing demand and diminishing supply of homografts has resulted in a search for alternatives. A biological conduit from the valved segment of bovine jugular vein (Contegra) has been used successfully as an alternative. METHODS: Early clinical and echocardiographic results were analyzed retrospectively for 20 patients (median age 14.4 years) who underwent a Ross procedure with Contegra as right ventricle to pulmonary artery conduit between November and June 2003 (during the last 31 months). RESULTS: There was no operative mortality and late mortality or morbidity during the mean follow-up of 13.8 +/- 9.1 months (range 1 to 31 months). No patient required reoperation. The median gradient at discharge was 16 +/- 4.5 mm Hg, which remained unchanged at last follow-up. No deterioration in conduit or conduit valve function was noted. CONCLUSIONS: This new bovine jugular vein conduit can be a viable alternative to a homograft in the Ross procedure. The early clinical and hemodynamic results are encouraging. Ease of availability and favorable handling and technical characteristics make it more attractive than a homograft. Xenograft origin of this conduit necessitates close follow-up for assessment of durability and longer-term results.     

Hemodynamic status after the Norwood procedure: a comparison of right ventricle-to-pulmonary artery connection versus modified Blalock-Taussig shunt

Background

The aim of this study is to compare hemodynamic status, in particular systemic oxygen delivery, in patients undergoing a Norwood procedure with a right ventricle-to-pulmonary artery (RV-PA) versus a modified Blalock-Taussig (mBT) shunt.

Methods

From June 2000 to November 2003, 44 consecutive neonates with hypoplastic left heart syndrome underwent a Norwood procedure. The first 25 patients received an mBT shunt; the subsequent 19 an RV-PA shunt. Hemodynamic data, including mixed venous oxygen saturation, was determined during the first 48 hours after surgery.

Results

The mBT and RV-PA shunt patients had no significant differences in systemic oxygen saturation, mixed venous oxygen saturation, arteriovenous oxygen saturation difference, or oxygen excess factor during the first 48 hours. Mixed venous saturation declined to a nadir in both groups at 6 to 12 hours. The RV-PA patients had significantly higher diastolic and mean blood pressures, and lower systolic blood pressure. Mean heart rate, common atrial pressure, and inotrope score did not differ between the two groups. The RV-PA patients received higher fraction of inspired oxygen and minute ventilation to achieve partial pressures of arterial oxygen and carbon dioxide, and pH, similar to mBT patients. Durations of mechanical ventilation, intensive care unit stay, and hospital stay did not differ between mBT and RV-PA patients. Operative survival in the mBT versus RV-PA group was 20 of 25 (80%) versus 17 of 19 (89%; p = 0.7).

Conclusions

Indicators of postoperative systemic oxygen delivery are equivalent in neonates who have undergone a Norwood procedure with an mBT or RV-PA shunt. Both mBT and RV-PA patients undergo similar declines in hemodynamic status 6 to 12 hours after surgery. Any advantages of one approach over the other lie in areas other than systemic oxygen delivery, such as resistance to physiologic insults, or preservation of ventricular function.     

Modified Norwood procedure with a handmade down-sizing valved right ventricle-to-pulmonary artery conduit

First-stage palliation of hypoplastic left heart syndrome has been revolutionized by the recent introduction of a right ventricle-to-pulmonary artery (RV-PA) conduit as an alternative to a systemic-to-pulmonary shunt. However, most conduits are unvalved, and the use of valved xenografts was abandoned during the early era of this operation. We performed a successful modified Norwood operation in a 2-month-old infant with aortic atresia and ventricular and atrial septal defects using a hand-made down-sizing valved graft as an RV-PA conduit. The postoperative course was uneventful with well-balanced pulmonary and arterial perfusion. We believe that minimization of the regurgitant volume from an unvalved prosthetic conduit by utilizing this modification might be of benefit in this particular group of patients.     

Pulmonary artery banding before Norwood procedure

Described here is the use of bilateral pulmonary artery banding as a means to achieve effective restoration of adequate systemic blood flow before a Norwood procedure in two newborns with hypoplastic left heart syndrome who presented after birth with a severe imbalance of Qp/Qs and multiorgan system dysfunction despite usual pharmacologic and ventilatory strategies.