In this study, we could demonstrate that glucose levels in the first month of life are associated with the development of ROP. Further studies have to determine if this association is causal or if hyperglycemia is just an expression of severity of illness.
This newly described technique can be performed safely with a high success rate and minimal procedural morbidity in EPNs. Early and midterm follow-up is encouraging. Future efforts should be directed toward developing specific devices for this unique application.
Purpose:To characterize the range of biventricular size and function evaluated by steady-state free precession (SSFP) cine magnetic resonance (MR) in a large cohort of patients with repaired tetralogy of Fallot (TOF), and to compare these measurements in those with a right ventricular outflow tract (RVOT) patch vs. a right ventricle-to-pulmonary artery (RV-PA) conduit.
Materials and Methods:Analysis of ventricular size and function in 300 consecutive examinations in patients with repaired TOF evaluated by SSFP cine MR.
Results:Of the 300 examinations performed in 256 patients, 69% had undergone repair with a RVOT patch and 31% with a RV-PA conduit. Compared to patients with RV-PA conduit, those with a RVOT patch had significantly more pulmonary regurgitation (PR) (38 Ϯ 17 vs. 23 Ϯ 16%, P Ͻ 0.0001), larger indexed RV end-diastolic volume (154 Ϯ 53 vs. 133 Ϯ 51 mL/m 2 , P ϭ 0.002), similar indexed end-systolic volume (80 Ϯ 39 vs. 74 Ϯ 46 mL/m 2 , P ϭ 0.31), higher ejection fraction (EF) (50 Ϯ 9 vs. 47 Ϯ 12%, P ϭ 0.037), and lower mass-to-volume ratio (0.29 Ϯ 0.08 vs. 0.36 Ϯ 0.13, P Ͻ 0.0001). Pulmonary regurgitation fraction correlated positively with RV end-diastolic volume index in the RVOT patch group (r ϭ 0.51, P Ͻ 0.0001) but not in the RV-PA conduit.
Conclusion:This study provides the range and distribution of biventricular size and function, and PR measured by MRI in a large contemporary cohort of patients with repaired TOF, and demonstrates important variations in RV mechanics between patients repaired with a RVOT patch and those with an RV-PA conduit.
Background:
The Fontan operation creates a total cavopulmonary connection, a circulation in which the importance of pulmonary vascular resistance is magnified. Over time, this circulation leads to deterioration of cardiovascular efficiency associated with a decline in exercise performance. Rigorous clinical trials aimed at improving physiology and guiding pharmacotherapy are lacking.
Methods:
The FUEL trial (Fontan Udenafil Exercise Longitudinal) was a phase III clinical trial conducted at 30 centers. Participants were randomly assigned udenafil, 87.5 mg twice daily, or placebo in a 1:1 ratio. The primary outcome was the between-group difference in change in oxygen consumption at peak exercise. Secondary outcomes included between-group differences in changes in submaximal exercise at the ventilatory anaerobic threshold, the myocardial performance index, the natural log of the reactive hyperemia index, and serum brain-type natriuretic peptide.
Results:
Between 2017 and 2019, 30 clinical sites in North America and the Republic of Korea randomly assigned 400 participants with Fontan physiology. The mean age at randomization was 15.5±2 years; 60% of participants were male, and 81% were white. All 400 participants were included in the primary analysis with imputation of the 26-week end point for 21 participants with missing data (11 randomly assigned to udenafil and 10 to placebo). Among randomly assigned participants, peak oxygen consumption increased by 44±245 mL/min (2.8%) in the udenafil group and declined by 3.7±228 mL/min (–0.2%) in the placebo group (
P
=0.071). Analysis at ventilatory anaerobic threshold demonstrated improvements in the udenafil group versus the placebo group in oxygen consumption (+33±185 [3.2%] versus –9±193 [–0.9%] mL/min,
P
=0.012), ventilatory equivalents of carbon dioxide (–0.8 versus –0.06,
P
=0.014), and work rate (+3.8 versus +0.34 W,
P
=0.021). There was no an improvement in myocardial performance index (–0.02 vs 0.01,
P
=0.030), but no change in reactive hyperemia index, or serum brain-type natriuretic peptide level.
Conclusions:
In the FUEL trial, treatment with udenafil (87.5 mg twice daily) was not associated with an improvement in oxygen consumption at peak exercise but was associated with improvements in multiple measures of exercise performance at the ventilatory anaerobic threshold.
Clinical Trial Registration:
URL:
https://www.clinicaltrials.gov
. Unique identifier: NCT02741115.
Clinical imaging methods are highly effective in the diagnosis of vascular pathologies, but they do not currently provide enough detail to shed light on the cause or progression of such diseases, and would be hard pressed to foresee the outcome of surgical interventions. Greater detail of and prediction capabilities for vascular hemodynamics and arterial mechanics are obtained here through the coupling of clinical imaging methods with computational techniques. Three-dimensional, patient-specific geometric reconstructions of the pediatric proximal pulmonary vasculature were obtained from x-ray angiogram images and meshed for use with commercial computational software. Two such models from hypertensive patients, one with multiple septal defects, the other who underwent vascular reactivity testing, were each completed with two sets of suitable fluid and structural initial and boundary conditions and used to obtain detailed transient simulations of artery wall motion and hemodynamics in both clinically measured and predicted configurations. The simulation of septal defect closure, in which input flow and proximal vascular stiffness were decreased, exhibited substantial decreases in proximal velocity, wall shear stress (WSS), and pressure in the post-op state. The simulation of vascular reactivity, in which distal vascular resistance and proximal vascular stiffness were decreased, displayed negligible changes in velocity and WSS but a significant drop in proximal pressure in the reactive state. This new patient-specific technique provides much greater detail regarding the function of the pulmonary circuit than can be obtained with current medical imaging methods alone, and holds promise for enabling surgical planning.
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