Andra Malikiwi

A New Look at Bronchopulmonary Dysplasia: Postcapillary Pathophysiology and Cardiac Dysfunction

Pulmonary hypertension (PH) and right ventricular function are the focus of cardiovascular effects of bronchopulmonary dysplasia (BPD). We assessed cardiac indexes reflecting systemic afterload and pulmonary venous back pressure as pathophysiologic factors. Cardiac parameters were measured by conventional echocardiography in 20 preterm infants with severe BPD and compared with those of 10 preterm infants with no BPD and 20 healthy term infants. In infants with severe BPD, PH was noted in 5 (25%) by tricuspid regurgitation Doppler jet ≥2.8 m/s and in 15 (75%) by time to peak velocity/right ventricular ejection time <0.34. Among systemic cardiac indexes, significant impairment of diastolic measures was noted in the BPD group compared with infants with no BPD and term infants. The significance persisted after adjusting for gestational age and birth weight. These included transmitral E/A ratio (1.07 ± 0.07 vs. 0.91 ± 0.04 vs. 0.89 ± 0.09; P < 0.0001), isovolumic relaxation time (68.8 ± 3.9 vs. 58.5 ± 7.8 vs. 54.2 ± 5.7 ms; P < 0.0001), mitral valve stroke volume (4.7 ± 0.7 vs. 5.6 ± 0.6 vs. 5.9 ± 0.1; P = 0.002), and myocardial performance index (0.33 ± 0.05 vs. 0.28 ± 0.01 vs. 0.27 ± 0.05; P = 0.03). Left ventricular output was significantly lower in the BPD cohort (183 ± 45 vs. 189 ± 9 vs. 191 ± 32 mL/kg/min; P = 0.03). Altered systemic (left-sided) cardiac function was noted in infants with BPD, which may lead to pulmonary venous congestion contributing to a continued need for respiratory support.

Systemic arterial stiffness in infants with bronchopulmonary dysplasia: potential cause of systemic hypertension

Objective:Systemic hypertension is common among preterm infants with severe bronchopulmonary dysplasia (BPD); the exact cause is unknown. The objective of this preliminary hypothesis generating study was to examine systemic arterial structure and vasomotor function in a cohort of preterm infants with severe BPD, using a cohort of preterm infants without BPD and a cohort of term infants for comparison.Study Design:After obtaining informed consent, we measured aortic wall thickness and vasomotor function by ultrasonography in 20 infants with severe BPD, 7 infants with no BPD, and compared them with 20 healthy term infants.Results:Maximum aortic thickness was significantly higher in infants with BPD (827±163 μm) compared to those with no BPD (674±22 μm) and term infants (657±67 μm) (unadjusted P<0.0001). The input impedance was similarly elevated in the infants with BPD (574±127 dynes s cm−5) compared to those with no BPD (325±24 dynes s cm−5) or term infants (328±113 dynes s cm−5) (unadjusted P<0.0001). Stiffness index was significantly higher in the infants with BPD (3.4±0.6) compared to those with no BPD (2.6±0.3) or term infants (2.3±0.4) (unadjusted P<0.0001). Systemic vascular resistance was also significantly elevated in the infants with BPD. The results remained significant even after adjusting for gestational age and birth weight. Measures of vasomotor function significantly correlated with blood pressure.Conclusion:The aortic wall thickness and vasomotor function are significantly altered in preterm infants with severe BPD. These findings may explain the higher incidence of systemic hypertension in this population.

Vasopressin as an adjunct therapy for pulmonary hypertension: a case report

Vasopressin is emerging as a therapeutic adjunct option towards treatment of shock states in the pediatric population. Its effects on pulmonary vasculature are less well understood. This report describes a 5-month-old infant with nitric oxide-unresponsive pulmonary hypertension, oxygenation failure, and systemic hypotension. Vasopressin therapy improved oxygenation and blood pressure and biventricular function, allowing weaning of nitric oxide and inotropic support. No decrease in coronary flow was noted. Conclusions: Vasopressin could be considered as an adjunct option in infants with pulmonary hypertension and systemic hypotension. Echocardiographic monitoring during treatment is recommended.