Jennifer C. Hirsch

Vasoactive–inotropic score as a predictor of morbidity and mortality in infants after cardiopulmonary bypass*

Objective: Inotrope score has been proposed as a marker of illness severity after pediatric cardiac surgery despite a lack of data to support its use as such. The goal of this study was to determine the association between inotropic/vasoactive support and clinical outcome in infants after cardiac surgery. Design: Retrospective chart review. Setting: Dedicated pediatric cardiothoracic intensive care unit at an academic, tertiary care medical center. Patients: One hundred seventy-four patients 0 to 6 months of age admitted to the cardiothoracic intensive care unit after cardiac surgery with cardiopulmonary bypass between August 2007 and June 2008. Forty-three percent were neonates, and 39% had functional single ventricle physiology. Interventions: None. Measurements and Main Results: Hourly doses of all vasoactive medications were recorded for the first 48 hrs after admission to the cardiothoracic intensive care unit and a vasoactive–inotropic score was calculated. The maximum vasoactive–inotropic score level over the first 48 hrs was a good predictor of poor clinical outcome (death, cardiac arrest, mechanical circulatory support, renal replacement therapy, and/or neurologic injury). After controlling for diagnosis, high maximum vasoactive–inotropic score was strongly associated with a poor outcome with an adjusted odds ratio of 8.1 (95% confidence interval, 3.4–19.2; p < .001) compared with patients with a low maximum vasoactive–inotropic score. High vasoactive–inotropic score was also associated with prolonged cardiothoracic intensive care unit stay, duration of mechanical ventilation, and time to negative fluid balance. Conclusions: The amount of cardiovascular support in the first 48 hrs after congenital heart surgery with cardiopulmonary bypass predicts eventual morbidity and mortality in young infants. The degree of support is best characterized by a maximum vasoactive–inotropic score obtained during this period. The usefulness of vasoactive–inotropic score as an independent predictor of clinical outcome in infants after cardiac surgery may have important implications for future cardiothoracic intensive care unit research. (Pediatr Crit Care Med 2010; 11:234–238)

Complete Repair of Tetralogy of Fallot in the Neonate: Results in the Modern Era

ObjectiveTo review more than a decade of experience with complete repair of tetralogy of Fallot (TOF) in neonates at the University of Michigan; to assess early and late survival, perioperative complications, and the incidence of reoperation; and to analyze patient, procedural, and morphologic risk factors to determine their effects on outcome. Summary Background DataPalliation of TOF with systemic-to-pulmonary artery shunts has been the accepted standard for symptomatic neonates and infants. Complete repair has traditionally been reserved for infants older than 6 months of age because of the perception that younger and smaller infants face an unacceptably high surgical risk. ResultsA retrospective review from August 1988 to November 1999 consisted of 61 consecutive symptomatic neonates with TOF who underwent complete repair. Thirty-one patients had TOF with pulmonary stenosis, 24 had TOF with pulmonary atresia, and 6 had TOF with nonconfluent pulmonary arteries. The mean age at repair was 16 ± 13 days, and the mean weight was 3.2 ± 0.7 kg. Before surgery, 36 patients were receiving an infusion of prostaglandin, 26 were mechanically ventilated, and 11 required inotropic support. Right ventricular outflow tract obstruction was managed with a transannular patch in 49 patients and a right ventricle-to-pulmonary artery conduit in 12. Cardiopulmonary bypass time averaged 71 ± 26 minutes. Hypothermic circulatory arrest was used in 52 patients (mean 38 ± 12 minutes). After cardiopulmonary bypass, the average intraoperative right/left ventricular pressure ratio was 55% ± 13%. There were no new clinically apparent neurologic sequelae after repair. The postoperative intensive care unit stay was 9.1 ± 8 days, with 6.8 ± 7 days of mechanical ventilation. There was one hospital death from postoperative necrotizing enterocolitis on postoperative day 71 and four late deaths, only one of which was cardiac-related. Actuarial survival was 93% at 5 years. Follow-up was available for all 60 hospital survivors and averaged 62 months (range 1–141 months). Twenty-two patients required a total of 24 reoperations at an average interval of 26 months after repair. Indications for reoperation included right ventricular outflow tract obstruction (19), branch pulmonary artery stenosis (11), severe pulmonary insufficiency (4), and residual ventricular septal defect (1). The 1-month, 1-year, and 5-year freedom from reoperation rates were 100%, 89%, and 58%, respectively. ConclusionsComplete repair of TOF in the neonate is associated with excellent intermediate-term survival. Although the reoperation rate is significant, this is to be expected with the complex right ventricular outflow tract and pulmonary artery anatomy seen in symptomatic neonates and the need for conduit replacement in patients with TOF with pulmonary atresia.

Fontan operation in the current era: a 15-year single institution experience.

Objective:Evaluate current risk factors for mortality and morbidity in patients undergoing the Fontan procedure at a single institution in the current era. Summary Background Data:An emphasis on early relief of volume and pressure overload culminating in the Fontan procedure has improved patient outcomes for patients with a single ventricle. Methods:A cross-sectional retrospective study was performed for 636 primary Fontan procedures between July 1992 and June 2007. Results:Anatomy included left ventricular hypoplasia in 64% and right ventricular hypoplasia in 36%. A lateral tunnel (LT) was performed in 92% and an extracardiac conduit (EC) in 8%. Hospital survival was 96%. Long-term survival was 97% at a mean follow-up of 50 months (range, 0–173 months). Ventricular anatomy and preoperative hemodynamics did not predict early or late survival. Longer aortic cross clamp (XC) time was associated with decreased late survival (P = 0.01). Fontan takedown was required in 3% and protein-losing enteropathy (PLE) developed in 6%. At follow-up, 98% of patients were either NYHA class I or II and 87% were in normal sinus rhythm. Patients with chest tube drainage >2 weeks had an increased risk of PLE (P < 0.0001) and diminished short- and long-term survival (P = 0.026 and P < 0.0001, respectively). Conclusions:The Fontan procedure can be performed with low risk regardless of ventricular anatomy. Duration of XC time is associated with survival. Prolonged CT drainage correlates with late PLE and diminished survival. There was a low prevalence of late rhythm disturbances and other complications.

Intermediate-term mortality and cardiac transplantation in infants with single-ventricle lesions: Risk factors and their interaction with shunt type

OBJECTIVE The study objective was to identify factors associated with death and cardiac transplantation in infants undergoing the Norwood procedure and to determine differences in associations that might favor the modified Blalock-Taussig shunt or a right ventricle-to-pulmonary artery shunt. METHODS We used competing risks methodology to analyze death without transplantation, cardiac transplantation, and survival without transplantation. Parametric time-to-event modeling and bootstrapping were used to identify independent predictors. RESULTS Data from 549 subjects (follow-up, 2.7 ± 0.9 years) were analyzed. Mortality risk was characterized by early and constant phases; transplant was characterized by only a constant phase. Early phase factors associated with death included lower socioeconomic status (P = .01), obstructed pulmonary venous return (P < .001), smaller ascending aorta (P = .02), and anatomic subtype. Constant phase factors associated with death included genetic syndrome (P < .001) and lower gestational age (P < .001). The right ventricle-to-pulmonary artery shunt demonstrated better survival in the 51% of subjects who were full term with aortic atresia (P < .001). The modified Blalock-Taussig shunt was better among the 4% of subjects who were preterm with a patent aortic valve (P = .003). Lower pre-Norwood right ventricular fractional area change, pre-Norwood surgery, and anatomy other than hypoplastic left heart syndrome were independently associated with transplantation (all P < .03), but shunt type was not (P = .43). CONCLUSIONS Independent risk factors for intermediate-term mortality include lower socioeconomic status, anatomy, genetic syndrome, and lower gestational age. Term infants with aortic atresia benefited from a right ventricle-to-pulmonary artery shunt, and preterm infants with a patent aortic valve benefited from a modified Blalock-Taussig shunt. Right ventricular function and anatomy, but not shunt type, were associated with transplantation.

Differential Case Ascertainment in Clinical Registry Versus Administrative Data and Impact on Outcomes Assessment for Pediatric Cardiac Operations

BACKGROUND Administrative datasets are often used to assess outcomes and quality of pediatric cardiac programs; however their accuracy regarding case ascertainment is unclear. We linked patient data (2004-2010) from the Society of Thoracic Surgeons Congenital Heart Surgery (STS-CHS) Database (clinical registry) and the Pediatric Health Information Systems (PHIS) database (administrative database) from hospitals participating in both to evaluate differential coding/classification of operations between datasets and subsequent impact on outcomes assessment. METHODS Eight individual benchmark operations and the Risk Adjustment in Congenital Heart Surgery, version 1 (RACHS-1) categories were evaluated. The primary outcome was in-hospital mortality. RESULTS The cohort included 59,820 patients from 33 centers. There was a greater than 10% difference in the number of cases identified between data sources for half of the benchmark operations. The negative predictive value (NPV) of the administrative (versus clinical) data was high (98.8%-99.9%); the positive predictive value (PPV) was lower (56.7%-88.0%). Overall agreement between data sources in RACHS-1 category assignment was 68.4%. These differences translated into significant differences in outcomes assessment, ranging from an underestimation of mortality associated with truncus arteriosus repair by 25.7% in the administrative versus clinical data (7.01% versus 9.43%; p = 0.001) to an overestimation of mortality associated with ventricular septal defect (VSD) repair by 31.0% (0.78% versus 0.60%; p = 0.1). For the RACHS-1 categories, these ranged from an underestimation of category 5 mortality by 40.5% to an overestimation of category 2 mortality by 12.1%; these differences were not statistically significant. CONCLUSIONS This study demonstrates differences in case ascertainment between administrative and clinical registry data for children undergoing cardiac operations, which translated into important differences in outcomes assessment.

Near-infrared spectroscopy: What we know and what we need to know—A systematic review of the congenital heart disease literature

OBJECTIVES Neurologic dysfunction is a problem in patients with congenital heart disease. Near-infrared spectroscopy may provide a real-time window into cerebral oxygenation. Enthusiasm for near-infrared spectroscopy has increased hopes of reducing neurologic dysfunction. However, potential gains need to be evaluated relative to cost before routine implementation. Responding to data in ways that seem intuitively beneficial can be risky when the long-term impact is unknown. Thus, we performed a systematic review of the literature on near-infrared spectroscopy in congenital heart disease. METHODS A literature search from 1950 to April 2007 for near-infrared spectroscopy in congenital heart disease was undertaken. We identified 54 manuscripts and\13 reviews. RESULTS There were 47 case series, 4 randomized trials, and 3 retrospective studies. Two studies had postdischarge follow-up, one incorporating neurologic testing. Neither of these studies demonstrated a benefit. One retrospective study, which included near-infrared spectroscopy and other intraoperative measures of cerebral perfusion, demonstrated a decrease in neurologic dysfunction using this combination of monitors. Three small studies were able to correlate near-infrared spectroscopy with other clinical and radiologic findings. CONCLUSIONS Many centers, and even entire countries, have adopted near-infrared spectroscopy as standard of care. The available data suggest that multimodality monitoring, including near-infrared spectroscopy, may be a useful adjunct. The current literature on the use of near-infrared spectroscopy alone, however, does not demonstrate improvement in neurologic outcome. The data correlating near-infrared spectroscopy findings with indirect measures of neurologic outcome or mortality are limited. Although near-infrared spectroscopy has promise for measuring regional tissue oxygen saturation, the lack of data demonstrating improved outcomes limits the support for widespread implementation.

Extracorporeal life support: experience with 2,000 patients.

This is a review of the University of Michigan experience with extracorporeal life support (ECLS) also known as extracorporeal membrane oxygenation (ECMO). Two thousand patients were managed with ECMO from 1973 to 2010. The first 1,000 patients were reported previously. Of the 2,000 patients, 74% were weaned from ECLS, and 64% survived to hospital discharge. In patients with respiratory failure, survival to hospital discharge was 84% in 799 neonates, 76% in 239 children, and 50% in 353 adults. Survival in patients with cardiac failure was 45% in 361 children and 38% in 119 adults. ECLS during extracorporeal cardiopulmonary resuscitation was performed in 129 patients, with 41% surviving to discharge. Survival decreased from 74 to 55% between the first and second 1,000 patients. The most common complication was bleeding at sites other than the head, with an incidence of 39%, and the least frequent complication was pump malfunction, with a 2% incidence. Intracranial bleeding or infarction occurred in 8% of patients, with a 43% survival rate. This is the largest series of ECLS at one institution reported in the world to date. Our experience has shown that ECLS saves lives of moribund patients with acute pulmonary and cardiac failure in all age groups.

A United Network for Organ Sharing analysis of heart transplantation in adults with congenital heart disease: Outcomes and factors associated with mortality and retransplantation

OBJECTIVES Heart transplantation in patients with adult congenital heart disease is increasing, yet no large studies have defined how this subgroup differs from other adult recipients. We investigated outcomes and risk factors for mortality and retransplantation among patients with adult congenital heart disease compared with adult recipients. METHODS A review was performed of 18- to 45-year-old patients undergoing heart transplantation from 1990-2008 reported to the United Network for Organ Sharing database. Trends were compared between 2 eras: era 1 (1990-1998) and era 2 (1999-2008). Multivariable semiparametric hazard models identified factors associated with time-related death and retransplantation. RESULTS Of 8496 patients identified, 575 had adult congenital heart disease. The prevalence of heart transplantation among adult recipients decreased by 28% over time (P < .001) and increased among patients with adult congenital heart disease by 41% (P < .001). Induction therapy use was less in patients with adult congenital heart disease (66%) compared with that seen in adult recipients (71%, P = .02). Steroid maintenance was less in patients with adult congenital heart disease (92%) compared with that seen in adult recipients (97%, P < .001). Post-heart transplantation survival among adult recipients improved over time (P = .02) but not among patients with adult congenital heart disease (P = .81). Overall post-heart transplantation mortality (P = .006) and retransplantation (P = .03) were significantly higher for patients with adult congenital heart disease than for adult recipients, mainly because of an early hazard phase. Adult congenital heart disease was a risk factor for both death (P < .001) and retransplantation (P = .04). Any induction therapy and steroid maintenance was associated with improved survival for all recipients (P = .001). CONCLUSIONS Adult congenital heart disease represent an increasing proportion of heart transplant recipients. Compared with adult recipients, patients with adult congenital heart disease experience higher post-heart transplantation mortality and retransplantation. Immunosuppression differs among patients with adult congenital heart disease and adult recipients. Further studies should investigate whether post-heart transplantation outcomes would be improved by more aggressive induction therapy or judicious steroid tapers.

Quality Measures for Congenital and Pediatric Cardiac Surgery

This article presents 21 “Quality Measures for Congenital and Pediatric Cardiac Surgery” that were developed and approved by the Society of Thoracic Surgeons (STS) and endorsed by the Congenital Heart Surgeons’ Society (CHSS). These Quality Measures are organized according to Donabedian’s Triad of Structure, Process, and Outcome. It is hoped that these quality measures can aid in congenital and pediatric cardiac surgical quality assessment and quality improvement initiatives.

Performance of CryoValve SG Decellularized Pulmonary Allografts Compared With Standard Cryopreserved Allografts

BACKGROUND There is no ideal option for pulmonary valve replacement in children. Cryopreserved pulmonary allografts frequently demonstrate early valve regurgitation and may elicit an immune response. To improve these shortcomings, the SynerGraft process (CryoLife, Kennesaw, GA) decellularizes an allograft, leaving only connective tissue, which then becomes repopulated with host cells. A previous study at our institution demonstrated superior short-term durability of the SynerGraft-processed CryoValve SG compared with standard allografts. Longer-term impact of the technology remains unknown. METHODS A single institution review was performed of all CryoValve SGs implanted between 2001 and 2004. Forty-one CryoValve SG patients and 41 age and diagnosis-matched standard allograft controls were evaluated. Demographics, survival, reintervention, and echocardiographic findings were analyzed. RESULTS There were no significant differences between groups in demographics, valve diameter, orthotopic-heterotopic allograft position, or follow-up. For the entire cohort, there was no difference in early or late insufficiency or stenosis at a mean follow-up of 46 +/- 14 months. However, freedom from moderate to severe insufficiency (>3+) was significantly better for CryoValve SG patients (p = 0.05). In addition, for patients greater than 2 years of age, CryoValve SGs were significantly less regurgitant (p = 0.045) and stenotic (p = 0.041). Long-term survival was identical at 85% (35 of 41). CONCLUSIONS When compared with standard allografts, CryoValve SGs demonstrate superior freedom from significant insufficiency at intermediate follow-up. In older children, CryoValve SGs display less insufficiency and stenosis. For infants, patient age, valve diameter, previous conduit, and rapid somatic growth would likely be the predominant factors leading to allograft failure.