Longitudinal Changes in Segmental Aortic Stiffness Determined by Cardiac Magnetic Resonance in Children and Young Adults With Connective Tissue Disorders (the Marfan, Loeys-Dietz, and Ehlers-Danlos Syndromes, and Nonspecific Connective Tissue Disorders).

Aortic stiffness measured by cardiac magnetic resonance (CMR) in connective tissue disorder (CTD) patients has been previously shown to be abnormal and to be associated with adverse aortic outcomes. The rate of increase in aortic stiffness with normal aging has been previously described. However, longitudinal changes in aortic stiffness have not been characterized in CTD patients. We examined longitudinal changes in CMR-derived aortic stiffness in children and young adults with CTDs. A retrospective analysis of 50 children and young adults (median age, 20 years; range, 0.2 to 49; 40% < 18 years old) with a CTD, and with at least 2 CMR examinations (total 152 examinations) over a median duration of 3.9 (1 to 13.2) years was performed. Aortic stiffness measures (strain, distensibility, and ß stiffness index) were calculated on each examination at the aortic root (AoR), ascending aorta, and descending aorta. Longitudinal changes in parameters were analyzed using linear mixed-effects models. Aortic strain and distensibility decreased with age, whereas the ß stiffness index increased at all aortic segments. The average rates of decline in distensibility (x10-3 mm Hg-1 per 10-year increase in age) were 0.7, 1.3, and 1 at the AoR, ascending aorta, and descending aorta, respectively. The rates of decline in distensibility were not associated with the rates of AoR dilation or surgical AoR replacement. In conclusion, on serial CMR measurements in children and young adults with CTDs, aortic stiffness progressively increased with age, with rates of change only slightly higher than those previously reported in healthy adults.

Segmental Aortic Stiffness in Children and Young Adults With Connective Tissue Disorders: Relationships With Age, Aortic Size, Rate of Dilation, and Surgical Root Replacement.

BACKGROUND: Aortic diameter is an imperfect predictor of aortic complications in connective tissue disorders (CTDs). Novel indicators of vascular phenotype severity such as aortic stiffness and vertebral tortuosity index have been proposed. We assessed the relation between aortic stiffness by cardiac MRI, surgical root replacement, and rates of aortic root dilation in children and young adults with CTDs. METHODS AND RESULTS: Retrospective analysis of cardiac MRI data on children and young adults with a CTD was performed to derive aortic stiffness measures (strain, distensibility, and ß-stiffness index) at the aortic root, ascending aorta, and descending aorta. Vertebral tortuosity index was calculated as previously described. Rate of aortic root dilation before cardiac MRI was calculated as change in echocardiographic aortic root diameter z score per year. In 83 CTD patients (median age, 24 years; range, 1-55; 17% <18 years of age; 60% male), ascending aorta distensibility was reduced in comparison with published normative values: median z score, -1.93 (range, -8.7 to 1.3; P<0.0001 versus normals). Over a median follow-up period of 2.7 years, there were no aortic dissections or deaths, but 16 of 83 (19%) patients underwent surgical aortic root replacement. In multivariable analysis, lower aortic root strain (P=0.05) and higher vertebral tortuosity index (P=0.01) were independently associated with aortic root replacement. Lower ascending aorta strain (P=0.02) was associated with a higher rate of aortic root dilation. CONCLUSIONS: Higher aortic stiffness is associated with higher rates of surgical aortic replacement and aortic root dilation in children and young adults with CTDs.

Cardiac status of children infected with human immunodeficiency virus who are receiving long-term combination antiretroviral therapy: results from the Adolescent Master Protocol of the Multicenter Pediatric HIV/AIDS Cohort Study.

IMPORTANCE: Prior to contemporary antiretroviral therapies (ARTs), children infected with human immunodeficiency virus (HIV) were more likely to have heart failure. This study suggests that highly active ART (HAART) does not appear to impair heart function. OBJECTIVE: To determine the cardiac effects of prolonged exposure to HAART on HIV-infected children. DESIGN: In the National Institutes of Health-funded Pediatric HIV/AIDS Cohort Study's Adolescent Master Protocol (AMP), we used linear regression models to compare echocardiographic measures. SETTING: A total of 14 US pediatric HIV clinics. PARTICIPANTS: Perinatally HIV-infected children receiving HAART (n = 325), HIV-exposed but uninfected children (n = 189), and HIV-infected (mostly HAART-unexposed) historical pediatric controls from the National Institutes of Health-funded Pulmonary and Cardiovascular Complications of Vertically Transmitted HIV Infection (P2C2-HIV) Study (n = 70). EXPOSURE Long-term HAART. MAIN OUTCOMES AND MEASURES: Echocardiographic measures of left ventricular (LV) function and structure. RESULTS: The 325 AMP HIV-infected children had lower viral loads, higher CD4 counts, and longer durations of ART than did the 70 HIV-infected children from the P2C2-HIV Study (all P < .001). The z scores for LV fractional shortening (a measure of cardiac function) were significantly lower among HIV-infected children from the P2C2-HIV Study than among the AMP HIV-infected group or the 189 AMP HIV-exposed but uninfected controls (P < .05). For HIV-infected children, a lower nadir CD4 percentage and a higher current viral load were associated with significantly lower cardiac function (LV contractility and LV fractional shortening z scores; all P = .001) and an increased LV end-systolic dimension z score (all P < .03). In an interaction analysis by HIV-infected cohort, the HIV-infected children from the P2C2-HIV Study with a longer ART exposure or a lower nadir CD4 percentage had lower mean LV fractional shortening z scores, whereas the mean z scores were relatively constant among AMP HIV-infected children (P < .05 for all interactions). CONCLUSIONS AND RELEVANCE: Long-term HAART appears to be cardioprotective for HIV-infected children and adolescents.

Sustained effects of cardiac rehabilitation in children with serious congenital heart disease.

OBJECTIVE: Past studies have documented the acute benefits of cardiac rehabilitation in children with congenital heart disease. It is not known whether these benefits persist. PATIENTS AND METHODS: Fifteen patients, ages 8 to 17 years, with complex congenital heart disease, whose exercise function immediately after a 12-week cardiac rehabilitation program was superior to that present on a precardiac rehabilitation exercise test, were restudied 6.9 +/- 1.6 months after completion of the cardiac rehabilitation program (approximately 1 year after the precardiac rehabilitation study). Changes in exercise function relative to baseline, precardiac rehabilitation exercise tests were also compared with changes observed in a group of 18 control subjects, with similar diagnoses, who also had 2 exercise tests separated by a year but did not undergo cardiac rehabilitation. RESULTS: The cardiac rehabilitation patients' exercise function did not change significantly over the 6.9-month period after the completion of the cardiac rehabilitation program; percentage of predicted peak oxygen consumption and peak work rate remained significantly superior to baseline, precardiac rehabilitation values. These changes were also associated with improvements in self-esteem, behavior, and emotional state. In contrast, among the control subjects, small, but statistically insignificant declines in peak oxygen consumption and peak work rate were observed on the final exercise test compared with values obtained at baseline, 1 year earlier. The improvements realized by the cardiac rehabilitation patients differed significantly from the concurrent changes observed among the control subjects and appeared to be a result of an increase in the oxygen pulse at peak exercise; significant changes in peak heart rate were not observed. CONCLUSIONS: In patients with congenital heart disease, cardiac rehabilitation produces significant, sustained improvements in exercise function, behavior, self-esteem, and emotional state.

Impact of cardiac rehabilitation on the exercise function of children with serious congenital heart disease.

OBJECTIVES: The exercise capacity of children with congenital heart disease (CHD) is often depressed. This depression is thought to be attributable to (1) residual hemodynamic defects and (2) deconditioning secondary to physical inactivity. We hypothesized that this latter component would be ameliorated by a formal cardiac rehabilitation program designed specifically for children. The objective of this study was to characterize the effect of a cardiac rehabilitation program on the exercise performance of children with CHD and to define the physiologic mechanisms that might account for any improvements that are observed. METHODS: Nineteen patients with CHD who were referred for exercise testing and found to have a peak oxygen consumption (VO2) and/or peak work rate <80% of predicted were enrolled in the study. Sixteen patients (11 Fontan patients, 5 with other CHD) completed the program and had postrehabilitation exercise tests, results of which were compared with the prerehabilitation studies. RESULTS: Improvements were found in 15 of 16 patients. Peak VO2 rose from 26.4 +/- 9.1 to 30.7 +/- 9.2 mL/kg per min; peak work rate from 93 +/- 32 to 106 +/- 34 W, and the ventilatory anaerobic threshold from 14.2 +/- 4.8 to 17.4 +/- 4.5 mL/kg per min. The peak heart rate and peak respiratory exchange ratio did not change, suggesting that the improvements were not attributable merely to an increased effort. In contrast, the peak oxygen pulse rose significantly, from 7.6 +/- 2.8 to 9.7 +/- 4.1 mL/beat, an improvement that can be attributed only to an increase in stroke volume and/or oxygen extraction at peak exercise. No patient experienced rehabilitation-related complications. CONCLUSION: Cardiac rehabilitation can improve the exercise performance of children with CHD. This improvement is mediated by an increase in stroke volume and/or oxygen extraction during exercise. Routine use of formal cardiac rehabilitation may greatly reduce the morbidity of complex CHD.