In Children’s Heart Disease: Decreasing Wound Infection Rates, Measuring Outcomes, and Refining Clinical Tools

Published on in CHOP News

For the 20th year, pediatric cardiology researchers and clinicians from multiple centers worldwide are sharing their findings at a large conference sponsored by the Cardiac Center at Children’s Hospital of Philadelphia. Cardiology 2017, the 20th Annual Update on Pediatric and Congenital Cardiovascular Disease, meets Feb. 22 to Feb. 26 in Orlando. Of the many investigators presenting research at the event, conference organizers chose eight clinical researchers as finalists for the Outstanding Investigator Award. The following news briefs highlight their presentations in congenital heart disease (CHD).

Multicenter Protocol Lowers Sternal Wound Infection Rates in Children’s Heart Surgery

This multicenter quality improvement project evaluated a protocol to prevent sternal wound infections in children who underwent cardiac surgery. Nine pediatric cardiac programs prospectively collected compliance data on 4,198 patients who underwent sternotomy for cardiac surgery. The study team found improvements in days between infections (68.2 days pre-protocol vs. 130 post-protocol) and in infection rates (1.9 percent of children pre-protocol vs. 1.5 percent post-protocol). One significant factor was the appropriate timing of pre-operative antibiotics, with significantly fewer infections when clinicians administered antibiotics within 60 minutes before the incision. There was a trend toward increased risk of infection among patients with delayed sternal closure for each day the sternum was open. The researchers suggest that these patients may benefit from earlier closure, and recommend that future quality improvement projects address this issue.

Cathy Woodward, et al, The University of Texas Health Science Center at San Antonio; Multicenter Quality Improvement Project to Prevent Sternal Wound Infections in Pediatric Cardiac Surgery Patients (abstract 78)

New Tool Evaluates Quality of Pediatric Cardiac ICUs after Surgery

This research group developed a novel risk-adjustment model to measure quality of care in cardiac intensive care units (CICUs) following pediatric cardiac surgery. The team performed a comparative analysis of hospitals in the Pediatric Cardiac Critical Care Consortium (PC4) using this method to measure mortality rates attributable to the quality of CICU care. They analyzed 8,543 CICU admissions from 23 hospitals, adjusting for severity of illness variables at the time of care transfer to the CICU.  Among the participating hospitals, four were statistical outliers — two with better than expected mortality; two with worse than expected mortality. This is the first report demonstrating variation in CICU quality across hospitals; the team found no apparent association between CICU volume and case mix adjusted mortality. These findings have important implications for hospitals performing pediatric cardiac surgery. Understanding quality across the different components of surgical care — intraoperative (surgery and anesthesia) vs. postoperative (CICU) care — may highlight opportunities to improve outcomes for these children.

Michael Gaies, et al, C.S. Mott Children’s Hospital; Variation in Risk Adjusted CICU Performance after Pediatric Cardiac Surgery: An Analysis of the Pediatric Cardiac Critical Care Consortium (abstract 226)

Researchers Develop Six-minute Walk Test Prediction Equation for Children with Pulmonary Hypertension

Investigators who evaluated predictive results for a standard pediatric tool, the six-minute walk test (6MWT), found that existing prediction equations developed for healthy children are not valid for children with pulmonary hypertension (PH). Therefore, they developed and validated a walk test prediction equation for children with PH. Children with congenital heart disease and PH are often small for their age, so the prediction equations for the distance covered in the 6MWT are a poor fit for this population. The study team retrospectively analyzed results from 711 6MWTs in children with PH, aged 4 to 18 years. All five of the existing pediatric prediction equations overestimated the walk distance among this patient population. The researchers created a new model, the Denver equation, taking into account differences in height, weight, heart rates, and the presence of congenital heart disease or a shunt. They validated this model with additional 6MWTs, and present it as a new reference for medical care and management of children with PH.

Julie Fernie, et al, Children’s Hospital Colorado; Evaluation of Predictive Models for Six Minute Walk Test among Children with Pulmonary Hypertension (abstract 129)

Outcomes in Anomalous Aortic Origin of a Coronary Artery Following a Standardized Approach

A single-center prospective study analyzed outcomes in a cohort of 163 patients with anomalous aortic origin of a coronary artery (AAOCA), the second leading cause of sudden cardiac arrest/death in young athletes in US. The study, from Dec. 2012 to Feb. 2017, followed a common algorithm, assessing myocardial perfusion with stress imaging and assessing coronary anatomy with computed tomography angiography. Of the 163 patients seen, 20 years of age or younger, 82 were considered high risk, defined by anatomical criteria and symptoms or evidence of myocardial ischemia. Predictors of high-risk lesion were older age at diagnosis, Black race, presence of intramural course and syncope on exertion.

Of the total cohort, the majority of patients (~80 percent) have been allowed to participate in unrestrictive sports activities. Thus far, 46 patients had surgery and only two (4 percent) have remained restricted from sports activities. All patients were alive at a median follow-up of 1.6 (IQR 0.7-2.8) years.

Silvana Molossi, et al, (Presenting author: Hitesh Agrawal), Texas Children’s Hospital, Baylor College of Medicine; Outcomes in Anomalous Aortic Origin of a Coronary Artery Following a Standardized Approach (abstract 103)

Two Shunt Types Differ in Cardiac Mechanics Results after Norwood Stage 2 Surgery

This study investigated contractility differences between two types of arterial shunts in children with a single right ventricle status post Norwood procedure before and after their stage 2 palliative surgery. Based on the fact that early survival benefits seen in patients with the RV to pulmonary artery shunt (RVPAs) over that of patients with the modified Blalock-Taussig shunt (mBTs) tend to dissipate over time, the study team investigated changes in contractility, afterload, and ventriculo-arterial coupling between the groups as measured by single beat noninvasive pressure-volume loop analysis. The researchers analyzed data from 185 patients in the Pediatric Heart Network Single Ventricle Reconstruction database, focusing on echocardiogram measurements pre-operatively and 14 months after superior cavopulmonary connection (SCPC). They found that RVPAs patients (n = 101) had greater contractility than mBTs patients (n = 84) before the SCPC, but that mBTs patients showed a trend toward greater contractility after SCPC than RVPAs patients. Measurements factoring into these results were end-systolic elastance, arterial elastance and RV end-diastolic volume. The researchers recommend further analysis of the relationship between contractility changes and differences in mid- and long-term mortality between both shunt groups.

Shahryar Chowdhury, et al, Medical University of South Carolina; The Effect of Shunt Type on Measures of Cardiac Mechanics after Stage 2 Palliation (abstract 110)

Large Cardiac Program Details Resource Costs in Single-ventricle Disease Patients

This single-center study measured the specific cost in total hospital resources for children diagnosed with single-ventricle cardiac defects (SVCD), a group of complex congenital heart conditions. The study team, from Children’s Hospital of Philadelphia, quantified specific resources used, from prenatal diagnosis through death, complete staged Fontan palliative surgeries or transplant. The researchers analyzed a cohort of 204 patients diagnosed with SVCD from 2004 to 2012. Of that total, 154 patients survived and 50 died during the study period; the median follow-up for six months post-Fontan completion was 3.4 years and median days hospitalized amounted to 23.2 days per patient-year. Patients who died during staged repair had a significantly greater resource burden compared to survivors, in days of hospitalization, echocardiograms, and cardiac catheterizations.

Michael Y Liu, MD, et al, Children’s Hospital of Philadelphia; Resource Utilization for Patients Diagnosed with Single Ventricle Cardiac Defects: a Fetus to Fontan Study. (abstract 99)

Catheter Ablation for Tachycardia Has Lower Success Rates in Complex Heart Disease

This multicenter retrospective study analyzed outcomes of catheter ablation in young patients with a common tachyarrhythmia, AV nodal reentrant tachycardia (AVNRT). The study analyzed results in 109 congenital heart disease (CHD) patients with AVNRT, aged 22.1 plus or minus 13.4 years. The team divided the patients into one group of 51 patients with complex CHD and a group of 58 patients with simple CHD. Of the whole group, 75 patients had radiofrequency ablation, 32 had cryoablation, and two had both. The patients with complex CHD had significantly longer procedure times and fluoroscopy times compared to patients with simple CHD. Outcomes were significantly better for patients with simple disease; after 3.2 years of follow-up, long-term success was 100 percent in the group with simple disease vs. 86.3 percent in the group with complex disease. Patients with complex disease had significantly higher risk of procedural failure and AV block. Overall, AVNRT can complicate the course of patients with CHD, especially those with right heart pressure and/or volume overload.

Daniel Beissel, et al, Children’s Mercy Kansas City; Atrioventricular Nodal Reentrant Tachycardia in Patients with Congenital Heart Disease: Outcome after Catheter Ablation (abstract 225)

National Ten-year Study Reveals Regional and Seasonal Variations in Kawasaki Disease

A large national study analyzed U.S. trends in seasonal variability, geographic region, race and ethnicity for Kawasaki disease (KD), a leading cause of acquired cardiovascular disease in children. The researchers collected data from early 2004 to late 2013 from the Pediatric Health Information Dataset, including all hospitalizations at 48 U.S. children’s hospitals. In total, 14,325 patients were discharged with a diagnosis of acute KD over the 10-year period, with patients ranging in age from younger than 1 month to age 20 years (median age was 2.7 years), and with 61 percent males. Nationally, total hospital discharges for acute KD increased by 47 percent from 2004 to 2013, with the overall rate also increasing by 15 percent. By region, the most striking increase in the acute KD discharge rate occurred in the South, where discharge rates among Hispanic, Black and White all increased. Lesser increases in the acute KD discharge rate were seen in the Northeast and West regions, with a decrease rate in the Midwest. Peak discharges occurred from December through March, with regional variation in which winter month that the peak occurred.

Svetlana Shugh et al, Texas Children’s Hospital, Baylor College of Medicine; Regional and Seasonal Trends of Kawasaki Disease in the United States (abstract 215)

Contact: Joey McCool Ryan, The Children’s Hospital of Philadelphia, (267) 258-6735 or