A new look at bronchopulmonary dysplasia: Role of systemic vascular & cardiac function in therapeutic options.

Abstract

Objective: Pulmonary hypertension and right ventricular performance and not left sided dysfunction are highlighted in the cardiovascular effects of bronchopulmonary dysplasia (BPD). Our study objective was to assess left sided vascular and cardiac indices which may reflect elevated systemic afterload and resultant pulmonary venous back pressure and consider possible therapeutic options. Method(s): Vascular biophysical and cardiac parameters were measured by ultrasonography in 20 infants with severe BPD and 20 healthy term infants. Result(s): Maximum aortic thickness was greater in BPD infants (827.5+/-163 vs 657.5+/-67.8 m, p<0.0001). Biophysical arterial markers [stiffness index (3.4+/- 0.6 vs 2.3+/-0.4, p<0.0001), input impedance (574.4+/-127.4 vs 328.1+/-113.2 dynes.s/cm5, p<0.0001) and circumferential wall tension (23126.8+/-2395 vs 20613.8+/-2242.4 d/cm, p=0.001)] were elevated. Left ventricular diastolic dysfunction [(elevated E/A ratio (0.9+/-0.09 vs 1.07+/-0.07, p<0.0001), prolonged E wave deceleration time (60.4+/-7 vs 75.6+/-7.9ms, p<0.0001), Isovolumic relaxation time (54 (49, 57) vs 68 (67, 71.7) ms, p<0.0001) and reduced pulmonary venousflow(VTI, 8.2+/-0.3 vs 5.4+/-0.4cm, p<0.0001) were noted. Themeanvelocity of circumferential fibre shortening (3+/-0.64 vs 1.7+/-0.42 circ/sec, p<0.0001) and Tei index (0.27+/-0.05 vs 0.33+/-0.05, p=0.001) was altered. Conclusion(s): Increased downstream stiffness, reduced myocardial contractility and elevated atrial/pulmonary venous back pressure may lead to pulmonary venous congestion and continued need for respiratory support. Systemic afterload reduction as a therapeutic option merits prospective analysis.