Shunt Reintervention and Time-Related Events After Norwood Operation: Impact of Shunt Strategy

Timing of reintervention influences survival and resource utilization following first-stage palliation of single ventricle heart disease

OBJECTIVE

Outcomes after first-stage palliation of single-ventricle heart disease are influenced by many factors, including the presence of residual lesions requiring reintervention. However, there is a dearth of information regarding the optimal timing of reintervention. We assessed if earlier reintervention would be favorably associated with in-hospital outcomes among patients requiring unplanned reinterventions after the Norwood operation.

METHODS

This was a single-center, retrospective review of all patients who underwent the Norwood procedure from January 1997 to November 2017 and required a predischarge unplanned surgical or transcatheter reintervention on 1 or more subcomponent areas repaired at the index operation. Outcomes of interest included in-hospital mortality or transplant, postoperative hospital length of stay, and inpatient cost. Associations between timing of reintervention and outcomes were assessed using logistic regression (mortality or transplant) or generalized linear models (postoperative hospital length of stay and cost), adjusting for baseline patient-related and procedural factors.

RESULTS

Of 500 patients who underwent the Norwood operation, 92 (18.4%) required an unplanned reintervention. Median time to reintervention was 12 days (interquartile range, 5-35 days). There were 31 (33.7%) deaths or transplants, median postoperative hospital length of stay was 49 days (interquartile range, 32-87 days), and median cost was $328,000 (interquartile range, $204,000-$464,000). On multivariable analysis, each 5-day increase in time to reintervention increased the odds of mortality or transplant by 20% (odds ratio, 1.2; 95% confidence interval, 1.1-1.3; P = .004). Longer time to reintervention was also significantly associated with greater postoperative hospital length of stay (P < .001) and higher cost (P < .001).

CONCLUSIONS

For patients requiring predischarge unplanned reinterventions after the Norwood operation, earlier reintervention is associated with improved in-hospital transplant-free survival and resource use.

Surgical reintervention on the neo-aorta after the Norwood operation

OBJECTIVES

We sought to identify the prevalence of surgical reintervention on the neo-aorta after Norwood procedure and its impact on long-term outcomes.

METHODS

We reviewed the medical records of all patients who underwent Norwood procedure. The impacts of surgical neoaortic reintervention on outcomes were analysed in each stage of palliation.

RESULTS

A total of 335 patients were included in this study. Thirty patients underwent surgical reintervention on the neo-aorta after Norwood procedure. The timing of initial reintervention was before stage II in 13 patients, at stage II in 7, between stage II and stage III in 5, at stage III in 3 and after stage III in 2. A reintervention before stage II was significantly associated with mortality (HR 14.4, 95% confidence interval 6.00-34.6, P < 0.001). In patients who underwent stage II (n = 251), reintervention had no significant impact on mortality. In patients who underwent stage III (n = 188), the previous reintervention was significantly associated with higher mean pulmonary pressure (P = 0.05) and a higher rate of reduced ventricular function (P = 0.002). Greater than mild atrioventricular valve regurgitation was significantly associated with the development of a neoaortic arch stenosis after stage II (P = 0.03).

CONCLUSIONS

Surgical reinterventions on the neo-aorta were required in each inter-stage phase. A surgical neoaortic reintervention was not related to increased mortality after stage II but significantly associated with a higher rate of reduced ventricular function and elevated mean pulmonary artery pressure.

Cobra-Head Cuffed Vascular Graft as Right Ventricle-to-Pulmonary Artery Shunt in Norwood Procedure

BACKGROUND

Right ventricle-to-pulmonary artery (RV-PA) shunt as a part of the Norwood procedure underwent many modifications. We present our experience with a commercially available polytetrafluoroethylene vascular graft with cobra-head cuff as an RV-PA shunt.

METHODS

A consecutive series of 52 children with hypoplastic left heart syndrome (median age 8 [range, 2-68] days, median weight 3200 [range, 2060-4400] g) underwent the Norwood procedure with a cobra-head cuffed RV-PA shunt (6 mm). The cuffed end was used for the central PA reconstruction. A retrospective analysis of clinical results, PAs development, and shunt-related complications, interventions, and technique of Glenn operation was performed. The study endpoint was Glenn operation with shunt removal or interstage death.

RESULTS

The hospital and late interstage mortality was 3.8% (n = 2 of 52) and 4% (n = 2 of 50), respectively, and was not shunt-related. During mean follow of 3.7 ± 2.5 years, 48 (92.3%) children underwent Glenn operation at a median age of 6 (range, 2.6-9.1) months. Angiography before the second stage revealed satisfactory branch PAs development (maximum and minimum McGoon ratio of 1.95 ± 0.36 and 1.38 ± 0.38, respectively). The mean maximal diameter of the left PA was smaller than that of the right PA (7.13 ± 2.1 mm vs 8.42 ± 2.2 mm; P = .017), without differences in mean minimal diameter. Two infants required stent implantation in proximal shunt end and 1 required urgent Glenn operation because distal shunt thrombosis. During Glenn operation, 11 (22.9%) children required patch reconstruction of central PAs.

CONCLUSIONS

The cobra-head cuffed graft allowed easy and reproducible reconstruction of the central PA during the Norwood procedure. Using this technique, the development of PAs is satisfactory, the rate of shunt-related complications and interventions is low, and the second stage can be performed without patch material.

Early Outcomes of Hypoplastic Left Heart Syndrome Infants: Meta-Analysis of Studies Comparing the Hybrid and Norwood Procedures

The hybrid strategy is an alternative to the traditional Norwood procedure for initial palliation of infants with hypoplastic left heart syndrome (HLHS) who are deemed to be at high surgical risk. Numerous single-center studies have compared the two procedures, showing similar early outcomes, although the cohort sizes are likely insufficiently powered to detect significant differences. The current meta-analysis aims to explore the early morbidity and mortality associated with the hybrid compared to the Norwood procedure. MEDLINE, Cochrane Libraries, and Embase were systematically searched, and 14 studies were included for statistical synthesis, comprising 263 hybrid and 426 Norwood patients. Early mortality was significantly higher in the hybrid patients (relative risk [RR] = 1.54, P < .05, 95% confidence interval [CI]: 1.02-2.34), whereas interstage mortality was comparable between the two groups (RR = 0.88, P > .05, 95% CI: 0.46-1.70). Six-month (RR = 0.89, P < .05, 95% CI: 0.80-1.00) and one-year (RR = 0.88, P < .05, 95% CI: 0.78-1.00) transplant-free survival was also inferior among the hybrid patients. Furthermore, the hybrid patients required more reinterventions following initial surgical palliation (RR = 1.48, P < .05, 95% CI: 1.09-2.01), although the two groups had comparable length of hospital and intensive care unit stay postoperatively. In conclusion, our results suggest that the hybrid procedure is associated with worse early survival compared to the traditional Norwood when used for initial palliation of infants with HLHS. However, due to the hybrid being used preferentially for high-risk patients, definitive conclusions regarding the efficacy of the procedure cannot be drawn.

Long term survival of hypoplastic left heart syndrome infants: Meta-analysis comparing outcomes from the modified Blalock-Taussig shunt and the right ventricle to pulmonary artery shunt

BACKGROUND

Stage 1 palliation of hypoplastic left heart syndrome (HLHS) involves the Norwood procedure combined with a modified Blalock-Taussig shunt (mBTS) or right ventricle to pulmonary artery shunt (RVPAS). Short-term survival has been described previously, whereas longer-term outcomes remain a subject of debate. This meta-analysis aimed to describe the short and long-term survival outcomes of these two shunts, and explore factors that might influence survival.

METHODS

Medline, Cochrane Libraries and EMBASE were systematically searched, and 32 studies were included for statistical synthesis, comprising 1348 mBTS and 1258 RVPAS patients.

RESULTS

While early in-hospital survival was superior in the RVPAS group (RR=1.5, p<0.05, 95% CI: 1.21-1.85), this difference was lost from 2years post-stage 1 palliation (RR=0.91, p>0.05, 95% CI: 0.79-1.04), and maintained unchanged up to 6years. This shift in survival was also reflected in inter-stage survival, with superior RVPAS outcomes between stage 1 and 2 (RR=1.62, p<0.05, 95% CI: 1.39-1.88), and equivalent outcomes between stage 2 and 3. Potential contributors to this included a significantly higher rate of pulmonary artery stenosis in the RVPAS group and an increased requirement for shunt re-intervention in this group prior to stage 2.

CONCLUSIONS

Despite early advantages, RVPAS and mBTS for palliation of hypoplastic left heart syndrome produced comparable long-term survival. The RVPAS patients experienced more pulmonary artery stenosis and requirement for shunt re-intervention. The impact of shunt type on quality and survival with a Fontan is yet to be assessed.

Mathematical Analysis and Physical Profile of Blalock-Taussig Shunt and Sano Modification Procedure in Hypoplastic Left Heart Syndrome: Review of the Literature and Implications for the Anesthesiologist

The first stage of surgical treatment for hypoplastic left heart syndrome (HLHS) includes the creation of artificial systemic-to-pulmonary connections to provide pulmonary blood flow. The modified Blalock-Taussig (mBT) shunt has been the technique of choice for this procedure; however, a right ventricle-pulmonary artery (RV-PA) shunt has been introduced into clinical practice with encouraging but still conflicting outcomes when compared with the mBT shunt. The aim of this study is to explore mathematical modeling as a tool for describing physical profiles that could assist the surgical team in predicting complications related to stenosis and malfunction of grafts in an attempt to find correlations with clinical outcomes from clinical studies that compared both surgical techniques and to assist the anesthesiologist in making decisions to manage patients with this complex cardiac anatomy. Mathematical modeling to display the physical characteristics of the chosen surgical shunt is a valuable tool to predict flow patterns, shear stress, and rate distribution as well as energetic performance at the graft level and relative to ventricular efficiency. Such predictions will enable the surgical team to refine the technique so that hemodynamic complications be anticipated and prevented, and are also important for perioperative management by the anesthesia team.

External counterpulsation of a systemic-to-pulmonary artery shunt increases coronary blood flow in neonatal piglets

BACKGROUND

Systemic-to-pulmonary artery shunt (SPS) palliation reduces coronary blood flow (CBF), which may precipitate myocardial ischemia postoperatively.

HYPOTHESIS

Counterpulsation (CP) of SPS augments CBF.

METHODS

Seven neonatal piglets (4.3 ± 0.23 kg) underwent sternotomy and ductus ligation. With a 5-mm polytetrafluoroethylene graft, SPS was created from innominate to pulmonary artery. A rigid shell holding a 9.5-mm diameter balloon was placed around the graft for CP. Using electrocardiographic signal, CP was initiated to trigger balloon inflation/deflation during the diastolic/systolic intervals, respectively. Instantaneous proximal and distal pulmonary artery and mid-anterior descending coronary artery flow rates were measured using transit time flow probes. Blood pressure and flow rates were recorded during three states: shunt closed, shunt open, and shunt open with CP.

STATISTICAL COMPARISON

Friedman's test and repeated measures analysis of variance.

RESULTS

Diastolic pressure decreased significantly with the shunt open (39 ± 8.4 to 28 ± 4.5 mm Hg, P = .05), then increased with CP (33 ± 2.3 mm Hg, P = .03). Median ratio of pulmonary to systemic flow (Qp/Qs) was 1.19, 1.9, and 1.53 with shunt closed, open, and open with CP, respectively. With CP, both diastolic coronary flow per minute (P = .018) and average diastolic flow rate per diastolic interval (P = .03) increased as well as total coronary flow per minute (P = .066; 19.6% ± 11.7%, 25.2% ± 17.0%, and 15.4% ± 13.9% change from shunt open, respectively). The percentage increase in average diastolic flow rate per diastolic interval correlated strongly with Qp/Qs (R (2) = .838).

CONCLUSIONS

In this model of SPS, CP increased diastolic blood pressure and CBF while maintaining significant augmentation of pulmonary blood flow (Qp/Qs). Shunt CP may aid in early postoperative management of palliative congenital heart disease.

Staged biventricular repair for neonates with left ventricular outflow tract obstruction, ventricular septal defect, and aortic arch obstruction

BACKGROUND

The purpose of this study is to evaluate clinical outcomes of neonates who underwent a Norwood operation as a first step of a planned biventricular repair and the impact of associated risk factors.

METHODS

A retrospective cohort study was performed on all neonates (n = 44) undergoing the Norwood operation as the first stage of a biventricular (Norwood-Rastelli) repair from January 2000 to December 2012 at a single center. Multivariable analysis was performed to identify predictors of survival.

RESULTS

Stage one mortality was 9%. The interstage survival for nonsyndromic and syndromic patients was 100% versus 46%, respectively (p < 0.001). Twenty-four patients (55%) underwent biventricular completion repair with no mortality. Freedom from reintervention after biventricular completion was 53% at 6 years. The overall survival for nonsyndromic patients versus syndromic patients was 86% versus 43%, respectively (p = 0.01). Genetic syndromes and prematurity were significant predictors of interstage mortality on multivariable analysis.

CONCLUSIONS

Staged biventricular repair for patients with complex left ventricular outflow tract obstruction, ventricular septal defect, and aortic arch obstruction can be achieved with excellent outcomes for neonates without genetic syndromes. The staged approach is associated with longer time to reintervention after the biventricular completion.

Pulmonary arterioplasty with decellularized allogeneic patches

BACKGROUND

Decellularized allogeneic nonvalved pulmonary artery patches for arterioplasty are a relatively new option compared with cryopreserved allogeneic, crosslinked xenogeneic bioprosthetic or synthetic materials. This study examines the midterm experience with a new decellularized allogeneic patch for congenital cardiac reconstructions.

METHODS

For this prospective postmarket approval, nonrandomized, inclusive observational study, we collected data on a consecutive cohort of 108 patients with cardiovascular reconstructions using 120 decellularized allogeneic pulmonary artery patches (MatrACELL; LifeNet Health, Inc, Virginia Beach, VA) between September 2009 and December 2012. One hundred of the patches were used for pulmonary arterioplasties. Two patients were lost early to follow-up and excluded from subsequent survival and durability analyses. Data included demographics, surgical outcomes, subsequent reoperations, and catheter reinterventions. These variables were also collected for an immediately preceding retrospective consecutive cohort of 100 patients with 101 pulmonary arterioplasty patches who received classical cryopreserved pulmonary artery allografts (n=59 patches and patients) or synthetic materials (n=41 patients with 42 patches) for pulmonary arterioplasties between 2006 and 2009.

RESULTS

In 106 patients with 118 decellularized patches, there were no device-related serious adverse events, no device failures, and no evidence of calcifications on chest roentgenograms. In contrast, the prior comparative pulmonary arterioplasty cohort of 100 patients experienced an overall 14.0% patch failure rate requiring device-related reoperations (p<0.0001) at mean duration of 194±104 days (range, 25 to 477 days).

CONCLUSIONS

The intermediate-term data obtained in this study suggest favorable performance by decellularized pulmonary artery patches, with no material failures or reoperations provoked by device failure.