Clinical, Experimental, and Computational Validation of a New Doppler-Based Index for Coarctation Severity Assessment.

BACKGROUND: Long-term morbidity including hypertension often persists in coarctation patients despite current guidelines. Coarctation severity can be invasively assessed via peak-to-peak catheter pressure gradient (PPCG), which is estimated noninvasively via simplified Bernoulli equation and conventionally reported as peak instantaneous Doppler gradient (PIDG). However, underlying simplifications of the equation limit diagnostic accuracy. We studied the diagnostic performance of a new Doppler-based diastolic index called the continuous flow pressure gradient (CFPG) versus conventional indices in assessing coarctation severity. METHODS: In a rabbit model mimicking human aortic coarctation, temporal blood pressure waveforms revealed the diastolic instantaneous pressure gradients and spectral Doppler features impacted by coarctation severity. We therefore hypothesized that CFPG provides superior correlation with coarctation gradients measured invasively. PIDG and CFPG were quantified using color flow echocardiography in humans and rabbits with discrete coarctations. Results were compared with PPCG in rabbits (n = 34) and arm-leg systolic gradients (n = 25) in humans via 1-way analysis of variance, Pearson's correlation, linear regression, and Bland-Altman analysis. RESULTS: A threshold of CFPG ≥ 4.6 mm Hg was identified via the Youden index as representative of PPCG ≥ 20 mm Hg (the current guideline value for coarctation intervention) in rabbits, while a CFPG ≥1.0 mm Hg represented an arm-leg systolic gradient ≥20 mm Hg in humans. Accuracy measures revealed superior correlation of CFPG (R2 > 0.80) and mild receiver operating characteristic improvement (area under the receiver operating characteristic curve, 0.94-0.95) compared with PIDG (R2 < 0.63; area under the receiver operating characteristic curve, 0.89-0.95). Inter-/intraobserver variability tested by intraclass correlation coefficient revealed measurement reliability with differences ≤8.2% and 10.7%, respectively. Computational simulations of anesthetized versus conscious hemodynamics showed parameters were minimally impacted by isoflurane inherent in the data used to derive CFPG. These results confirm the potential diagnostic accuracy of CFPG in echocardiography-based coarctation severity assessment. We are optimistic that CFPG will be useful for translation of results from preclinical studies that revisit current guidelines to limit morbidity in humans with aortic coarctation.

Chest tube removal algorithm is associated with decreased chest tube duration in pediatric cardiac surgical patients.

OBJECTIVE: Management of chest tubes in adult and pediatric patients is highly variable. There are no published guidelines for pediatric cardiac surgical patients. Our center undertook a quality improvement project aimed at reducing chest tube duration and length of stay in postsurgical pediatric cardiac patients. METHODS: A work group identified 2 opportunities for reducing chest tube duration: standardizing removal criteria and increasing frequency of assessment for removal. An algorithm was created, and chest tube assessments were increased to twice daily. All postsurgical cardiac patients were managed according to the algorithm. Outcome measure reporting was limited to patients age 1 month to 18 years with a biventricular surgical procedure. Outcome measures included chest tube duration, cardiac intensive care unit and hospital length of stay, and cost of hospitalization. Process measure was documentation of chest tube assessments. The balancing measure was chest tube reinsertions. RESULTS: Between April 2016 and July 2018, 126 patients aged 1 month to 18 years underwent a biventricular surgical procedure. Mean chest tube duration decreased from 61 to 47 hours. Cardiac intensive care unit length of stay decreased from 141 hours to 89 hours, hospital length of stay decreased from 266 to 156 hours, and average hospitalization cost decreased from $75,881 to $48,118. There was no increase in chest tube reinsertions. CONCLUSIONS: Implementation of a chest tube removal algorithm for pediatric cardiac surgery patients resulted in decreased chest tube duration and was associated with decreased length of stay and costs without an increase in reinsertions. More significant impact may be attainable with more aggressive approach to removal.

Transposition of the great arteries--outcomes and time interval of early neonatal repair.

BACKGROUND: This study evaluates the relationship of morbidity and resource utilization with the timing of early neonatal repair of transposition of the great arteries and intact ventricular septum (d-TGA/IVS). METHODS: All patients with d-TGA/IVS who underwent arterial switch in the first 14 days of life, between January 2000 and May 2011, were reviewed. Patients undergoing repair at ≤ 4 days of age were categorized as group I, 5 to 7 days as group II, and 8 to 14 days as group III. Outcomes included mortality, morbidity, and resource utilization. RESULTS: Hospital survival was 69 (98.6%) of 70. The length of stay (LOS) and total charges were lowest in group I--15.5 days compared to group II--18.0 days and group III--23.5 days (P = .005); group I--US$128,219 compared to group II--US$141,729 and group III--US$217,427 (P = .0006). Using regression analysis to account for potentially confounding effects of multiple variables and treating time as a continuous variable demonstrated that age at surgery was significantly associated with total LOS (P = .029), hospital charges (P = .029) and intensive care unit charges (P = .002). Younger age at repair was not associated with worse outcomes for any measure of morbidity. CONCLUSIONS: Earlier repair of d-TGA/IVS was associated with decreased resource utilization and no detriment to clinical outcomes. Further analysis based on a larger cohort of patients is needed to verify these results that have important implications for improving the value of care.