Background Circulatory vulnerability reflected by low systemic venous oxygen saturation after surgical palliation of hypoplastic left heart syndrome predicts adverse neurologic outcome and reduced ...survival, and targeting venous saturation may improve outcome. We herein test the hypothesis that near-infrared spectroscopy (NIRS)-derived cerebral and somatic/renal regional saturations can predict survival. Methods Patient data, from a prospective Institutional Review Board-approved registry of hemodynamic measures after initial palliation of hypoplastic left heart syndrome, were analyzed with logistic and multivariable mixed regression methods to determine relationships between standard hemodynamic measures, direct and NIRS measures of saturation, and outcome. The primary outcome measure was survival through hospital discharge and 30 days. Results From the entire cohort of 329 patients, complete data for comparative analysis of physiologic predictors were available from 194 patients. The early survival rate was 92.1%; extracorporeal membrane oxygenation was used in 8.8% of patients. The mean arterial pressure, arterial cerebral, and somatic cerebral NIRS saturation differences were significantly higher for survivors versus nonsurvivors. Multivariable analysis found cerebral and somatic NIRS saturations, heart rate, and arterial pressure as predictors of outcome. Bivariate analysis of mean arterial pressure and somatic saturation allowed early identification of low cardiac output and high mortality risk. Conclusions Continuous noninvasive measurement of regional cerebral and somatic NIRS saturations in the early postoperative period can predict outcomes of early mortality and extracorporeal membrane oxygenation use in hypoplastic left heart syndrome. Because outcomes were strongly determined by NIRS measures at 6 hours, early postoperative NIRS measures may be rational targets for goal-directed interventions.
BACKGROUND:In the SVR trial (Single Ventricle Reconstruction), 1-year transplant-free survival was better for the Norwood procedure with right ventricle-to-pulmonary artery shunt (RVPAS) compared ...with a modified Blalock–Taussig shunt in patients with hypoplastic left heart and related syndromes. At 6 years, we compared transplant-free survival and other outcomes between the groups.
METHODS:Medical history was collected annually using medical record review, telephone interviews, and the death index. The cohort included 549 patients randomized and treated in the SVR trial.
RESULTS:Transplant-free survival for the RVPAS versus modified Blalock–Taussig shunt groups did not differ at 6 years (64% versus 59%, P=0.25) or with all available follow-up of 7.1±1.6 years (log-rank P=0.13). The RVPAS versus modified Blalock–Taussig shunt treatment effect had nonproportional hazards (P=0.009); the hazard ratio (HR) for death or transplant favored the RVPAS before stage II surgery (HR, 0.66; 95% confidence interval, 0.48–0.92). The effect of shunt type on death or transplant was not statistically significant between stage II to Fontan surgery (HR, 1.36; 95% confidence interval, 0.86–2.17; P=0.17) or after the Fontan procedure (HR, 0.76; 95% confidence interval, 0.33–1.74; P=0.52). By 6 years, patients with RVPAS had a higher incidence of catheter interventions (0.38 versus 0.23/patient-year, P<0.001), primarily because of more interventions between the stage II and Fontan procedures (HR, 1.72; 95% confidence interval, 1.00–3.03). Complications did not differ by shunt type; by 6 years, 1 in 5 patients had had a thrombotic event, and 1 in 6 had had seizures.
CONCLUSIONS:By 6 years, the hazards of death or transplant and catheter interventions were not different between the RVPAS versus modified Blalock–Taussig shunt groups. Children assigned to the RVPAS group had 5% higher transplant-free survival, but the difference did not reach statistical significance, and they required more catheter interventions. Both treatment groups have accrued important complications.
CLINICAL TRIAL REGISTRATION:URLhttps://www.clinicaltrials.gov. Unique identifierNCT00115934.
Objectives Neonates with hypoplastic left heart syndrome have significant hemodynamic threats to cerebral perfusion and are at risk of reduced neurodevelopmental performance. We hypothesized that ...cerebral hypoxia, detectable by near-infrared spectroscopy in the early postoperative period, would be related to later neurodevelopmental performance. Methods The study population was a sequential cohort of patients who had undergone stage 1 palliation of hypoplastic left heart syndrome under standard conditions, including neonatal perioperative monitoring with cerebral near-infrared spectroscopy, and who had undergone a neurodevelopmental assessment at age 4 to 5 years. The neonatal demographic and 48-hour perioperative hemodynamic parameters, including cerebral oxygen saturation, were tested for their relationship to 4 domains of neurodevelopmental performance, including visual-motor integration in childhood in univariate and multivariate models. The neurodevelopmental scores were classified as low if less than 85 (−1 standard deviation) and abnormal if less than 70 (−2 standard deviations). Results For the 51 patients in the surgical cohort, the early survival was 94%, the cumulative survival was 86%, and the neurodevelopmental assessment was completed by 21 (48%) of the survivors, without evidence of an ascertainment bias. At the test age of 56.3 ± 5.5 months, the composite neurodevelopmental index, constructed from equally weighted measures in 4 domains, was 97.6 ± 9.6, not different from the age-based norms, with 3 of 21 in the low range and none abnormal. The mean visual-motor integration was 93.4 ± 14, slightly less than the population norm ( P < .05), with 2 of 21 having low scores and 1 abnormal scores. In patients with low to abnormal visual-motor integration, the perioperative stage 1 palliation cerebral oxygenation saturation was significantly lower (63.6 ± 8.1 vs 67.8 ± 8.1, P < .05). Two patients had discrete embolic strokes after their initial hospitalization; the occurrence of late stroke reduced the visual-motor integration performance but was not related to the early cerebral oxygen saturation. Nonlinear relationships of cerebral oxygen saturation to the neurodevelopmental measures found cerebral oxygen saturation thresholds of 49% to 62%. The hours at a cerebral oxygen saturation less than 45% and 55% were related to low visual-motor integration and neurodevelopmental index scores in the univariate and multivariate models. A multivariate model of age and weight at stage 1 palliation, cerebral oxygen saturation, arterial oxygen saturation, cardiopulmonary bypass and deep hypothermic circulatory arrest times, and later stroke predicted visual-motor integration to an important degree (R2 = 0.53, P < .001). The actual and predicted visual-motor integration and neurodevelopmental index were normal when a cerebral oxygen saturation less than 45% and other risk conditions were avoided. Conclusions Neurodevelopmental performance was related to demographic, neonatal perioperative physiologic, and later factors. Perioperative cerebral oxygenation assessed by near-infrared spectroscopy can detect hypoxic-ischemic conditions associated with injury and reduced neurodevelopmental performance and was the most significant physiologic factor identified. These data suggest that efforts to avoid cerebral hypoxia are likely to improve the outcomes in this high-risk population.
BACKGROUND—In the Single Ventricle Reconstruction (SVR) trial, 1-year transplantation-free survival was better for the Norwood procedure with right ventricle–to–pulmonary artery shunt (RVPAS) ...compared with a modified Blalock-Taussig shunt (MBTS). At 3 years, we compared transplantation-free survival, echocardiographic right ventricular ejection fraction, and unplanned interventions in the treatment groups.
METHODS AND RESULTS—Vital status and medical history were ascertained from annual medical records, death indexes, and phone interviews. The cohort included 549 patients randomized and treated in the SVR trial. Transplantation-free survival for the RVPAS versus MBTS groups did not differ at 3 years (67% versus 61%; P=0.15) or with all available follow-up of 4.8±1.1 years (log-rank P=0.14). Pre-Fontan right ventricular ejection fraction was lower in the RVPAS group than in the MBTS group (41.7±5.1% versus 44.7±6.0%; P=0.007), and right ventricular ejection fraction deteriorated in RVPAS (P=0.004) but not MBTS (P=0.40) subjects (pre-Fontan minus 14-month mean, −3.25±8.24% versus 0.99±8.80%; P=0.009). The RVPAS versus MBTS treatment effect had nonproportional hazards (P=0.004); the hazard ratio favored the RVPAS before 5 months (hazard ratio=0.63; 95% confidence interval, 0.45–0.88) but the MBTS beyond 1 year (hazard ratio=2.22; 95% confidence interval, 1.07–4.62). By 3 years, RVPAS subjects had a higher incidence of catheter interventions (P<0.001) with an increasing HR over time (P=0.005)<5 months, 1.14 (95% confidence interval, 0.81–1.60); from 5 months to 1 year, 1.94 (95% confidence interval, 1.02–3.69); and >1 year, 2.48 (95% confidence interval, 1.28–4.80).
CONCLUSIONS—By 3 years, the Norwood procedure with RVPAS compared with MBTS was no longer associated with superior transplantation-free survival. Moreover, RVPAS subjects had slightly worse right ventricular ejection fraction and underwent more catheter interventions with increasing hazard ratio over time.
CLINICAL TRIAL REGISTRATION—URLhttp://www.clinicaltrials.gov. Unique identifierNCT00115934.
Objective For infants with single ventricle malformations undergoing staged repair, interstage mortality is reported at 2% to 20%. The Single Ventricle Reconstruction trial randomized subjects with a ...single morphologic right ventricle undergoing a Norwood procedure to a modified Blalock–Taussig shunt (MBTS) or a right ventricle-to-pulmonary artery shunt (RVPAS). The aim of this analysis was to explore the associations of interstage mortality and shunt type, and demographic, anatomic, and perioperative factors. Methods Participants in the Single Ventricle Reconstruction trial who survived to discharge after the Norwood procedure were included (n = 426). Interstage mortality was defined as death postdischarge after the Norwood procedure and before the stage II procedure. Univariate analysis and multivariable logistic regression were performed adjusting for site. Results Overall interstage mortality was 50 of 426 (12%)—13 of 225 (6%) for RVPAS and 37 of 201 (18%) for MBTS (odds ratio OR for MBTS, 3.4; P < .001). When moderate to severe postoperative atrioventricular valve regurgitation (AVVR) was present, interstage mortality was similar between shunt types. Interstage mortality was independently associated with gestational age less than 37 weeks (OR, 3.9; P = .008), Hispanic ethnicity (OR, 2.6; P = .04), aortic atresia/mitral atresia (OR, 2.3; P = .03), greater number of post-Norwood complications (OR, 1.2; P = .006), census block poverty level ( P = .003), and MBTS in subjects with no or mild postoperative AVVR (OR, 9.7; P < .001). Conclusions Interstage mortality remains high at 12% and is increased with the MBTS compared with the RVPAS if postoperative AVVR is absent or mild. Preterm delivery, anatomic, and socioeconomic factors are also important. Avoiding preterm delivery when possible and close surveillance after Norwood hospitalization for infants with identified risk factors may reduce interstage mortality.
Objective Infants who undergo Norwood stage 1 palliation (S1P) continue with high-risk circulation until stage 2 palliation (S2P). Routine care during the interstage period is associated with 10% to ...20% mortality. This report illustrates the sustained reduction of interstage mortality over 10 years associated with use of home monitoring. Methods Daily monitoring of oxygen saturation and weight was done for all patients discharged to home after S1P. Notification of the care team occurred for oxygen saturation <75% or >90%, weight gain < 20 g over 3 days, weight loss > 30 g, or intake < 100 cc/kg/d. Breach of these criteria marked an interstage event. Interstage outcomes are reported. Patient characteristics and perioperative variables were compared between patients with and without interstage events. Results Over 10 years, 157 patients were discharged after S1P with home monitoring. Interstage survival was 98%. Breach of home criteria occurred in 59% (93 out of 157), with violation of oxygen saturation <75% the most common event. Patient characteristics, operative data, and early postoperative morbidity did not differ between patients with and without events. Conclusions Home monitoring after S1P is associated with excellent interstage survival. Although a breach of monitoring criteria occurred in more than half of patients, our analysis failed to identify independent predictors of interstage events. Analysis of variables predicting mortality could not be assessed due to the low frequency of death in this cohort. Failure to identify specific variables for interstage events suggests that home monitoring, as part of an interstage surveillance program, should be applied to all S1P hospital survivors.
The objectives of this review are to discuss the technology and clinical interpretation of near infrared spectroscopy oximetry and its clinical application in patients with congenital heart disease.
...MEDLINE and PubMed.
Near infrared spectroscopy provides a continuous noninvasive assessment of tissue oxygenation. Over 20 years ago, near infrared spectroscopy was introduced into clinical practice for monitoring cerebral oxygenation during cardiopulmonary bypass in adults. Since that time, the utilization of near infrared spectroscopy has extended into the realm of pediatric cardiac surgery and is increasingly being used in the cardiac ICU to monitor tissue oxygenation perioperatively.
Objective To evaluate outcomes of systemic to pulmonary artery shunts (SPS) in patients weighing less than 3 kg with regard to shunt type, shunt size, and surgical approach. Methods Patients weighing ...less than 3 kg who underwent modified Blalock-Taussig or central shunts with polytetrafluoroethylene grafts at our institution from January 1, 2000, to May 31, 2011, were reviewed. Patients who had undergone other major concomitant procedures were excluded from the analysis. Primary outcomes included mortality (discharge mortality and mortality before next planned palliative procedure or definitive repair), cardiac arrest and/or extracorporeal membrane oxygenation (ECMO), and shunt reintervention. Results In this cohort of 80 patients, discharge survival was 96% (77/80). Postoperative cardiac arrest or ECMO occurred in 6/80 (7.5%), and shunt reintervention was required in 14/80 (17%). On univariate analysis, shunt reintervention was more common in patients with 3-mm shunts (11/30, 37%) compared with 3.5-mm (2/36, 6%) or 4-mm shunts (1/14, 7%) ( P < .003). There were no statistically significant associations between shunt type, shunt size, or surgical approach and cardiac arrest/ECMO or mortality. Multiple logistic regression demonstrated that a shunt size of 3 mm ( P = .019) and extracardiac anomaly ( P = .047) were associated with shunt reintervention, whereas no variable was associated with cardiac arrest/ECMO or mortality. Conclusions In this high-risk group of neonates weighing less than 3 kg at the time of SPS, survival to discharge and the next planned surgical procedure was high. Outcomes were good with the 3.5- and 4-mm shunts; however, shunt reintervention was common with 3-mm shunts.
Previous studies suggest that birth before 39 weeks’ gestational age (GA) is associated with higher perioperative mortality and morbidity after congenital heart surgery. The optimal approach to ...timing of cardiac operation in premature infants remains unclear. We investigated the impact of GA at birth and corrected GA at surgery on postoperative outcomes using the Pediatric Cardiac Critical Care Consortium (PC4) database.
Infants undergoing selected index cardiac operations before the end of the neonatal period were included (n = 2298). GA at birth and corrected GA at the time of the index cardiac operation were used as categorical predictors and fitted as a cubic spline to assess nonlinear relationships. The primary outcome was hospital mortality. Multivariable logistic regression models assessed the association between predictors and outcomes while adjusting for confounders.
Late-preterm (34-36 weeks) birth was associated with increased odds of mortality compared with full-term (39-40 weeks) birth, while early-term (37-38 weeks) birth was not associated with increased mortality. Corrected GA at surgery of 34 to 37 weeks compared with 40 to 44 weeks was associated with increased mortality. When analyzing corrected GA at surgery as a continuous predictor of outcome, odds of survival improve as patients approach 39 weeks corrected GA.
Contrary to previous literature, we did not find an association between early-term birth and hospital mortality at PC4 hospitals. Our analysis of the relationship between corrected GA and mortality suggests that operating closer to full-term corrected GA may improve survival.
The hemoglobin threshold for a decision to transfuse red blood cells in univentricular patients with parallel circulation is unclear. A pediatric expertise initiative put forth a “weak ...recommendation” for avoiding reflexive transfusion beyond a hemoglobin of 9 g/dL. We have created a mathematical model to assess the impact of hemoglobin thresholds in patients with parallel circulation.
A univentricular circulation was mathematically modeled. We examined the impact on oxygen extraction ratios and systemic and venous oxygen saturations by varying hemoglobin levels, pulmonary to systemic blood flow ratios, and total cardiac output.
Applying a total cardiac index of 6 L/m2/min, oxygen consumption of 150 mL/min/m2, and a Qp/Qs ∼ 1, we found a hemoglobin level of 9 g/dL would lead to severe arterial (arterial oxygen saturation <70%) and venous (systemic venous oxygen saturation <40%) hypoxemia. To operate above the critical oxygen economy boundary (systemic venous oxygen saturation ∼40%) and maintain arterial oxygen saturation >70% would require either increasing the cardiac index to ∼ 9 L/m2/min or increasing the hemoglobin to greater than 13 g/dL. Further, we found a greater improvement in arterial and venous saturation arises when hemoglobin is augmented from levels below 12 g/dL.
Based on our model, a hemoglobin level of 9 g/dL would require a constricted set of features to sustain arterial saturations >70% and systemic venous saturations >40% and would risk unfavorable oxygen economy with elevations in oxygen consumption. Further prospective clinical studies are needed to delineate the impact of restrictive transfusion practices in univentricular circulation.
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