Real-Time Magnetic Resonance Assessment of Septal Curvature Accurately Tracks Acute Hemodynamic Changes in Pediatric Pulmonary Hypertension

Abstract

Background-This study assesses the relationship between septal curvature and mean pulmonary artery pressure and indexed pulmonary vascular resistance in children with pulmonary hypertension. We hypothesized that septal curvature could be used to estimate right ventricular afterload and track acute changes in pulmonary hemodynamics. Methods and Results-Fifty patients with a median age of 6.7 years (range, 0.45-16.5 years) underwent combined cardiac catheterization and cardiovascular magnetic resonance. The majority had idiopathic pulmonary arterial hypertension (n=30); the remaining patients had pulmonary hypertension associated with repaired congenital heart disease (n=17) or lung disease (n=3). Mean pulmonary artery pressure and pulmonary vascular resistance were acquired at baseline and during vasodilation. Septal curvature was measured using real-time cardiovascular magnetic resonance. There was a strong correlation between mean pulmonary artery pressure and SC min at baseline and during vasodilator testing (r=-0.81 and -0.85, respectively; P<0.01). A strong linear relationship also existed between pulmonary vascular resistance and minimum septal curvature indexed to cardiac output both at baseline and during vasodilator testing (r=-0.88 and -0.87, respectively; P<0.01). Change in septal curvature metrics moderately correlated with absolute change in mean pulmonary artery pressure and pulmonary vascular resistance, respectively (r=0.58 and -0.74; P<0.01). Septal curvature metrics were able to identify vasoresponders with a sensitivity of 83% (95% confidence interval, 0.36-0.99) and a specificity of 91% (95% confidence interval, 0.77-0.97), using the Sitbon criteria. Idiopathic pulmonary arterial hypertension subgroup analysis revealed 3 responders with ΔSC min values of 0.523, 0.551, and 0.568. If the middle value of 0.551 is taken as a cutoff, the approximate sensitivity would be 67% and the specificity would be 93%. Conclusions-Septal curvature metrics are able to estimate right ventricular afterload and track acute changes in pulmonary hemodynamics during vasodilator testing. This suggests that septal curvature could be used for continuing assessment of load in pulmonary hypertension. (Circ Cardiovasc Imaging. 2014;7:706-713.)

Cardiovascular magnetic resonance imaging derived septal curvature in neonates with bronchopulmonary dysplasia associated pulmonary hypertension

“…Septal curvature was the only independent variable associated with need for PH therapy in multivariable analysis. This is consistent with prior reports which have demonstrated that CMR derived minimum septal curvature and echocardiography derived septal curvature measured at end systole are associated with elevated RV pressure [ 17 , 28 , 29 ]. In the report by Pandya et al CMR derived septal curvature correlated with mean pulmonary artery pressure and pulmonary vascular resistance in older pediatric PH patients [ 17 ].…”

“…Septal curvature was measured from the short axis stack at the level of the papillary muscles as previously described [ 17 ] using ImageJ (National Institutes of Health, Bethesda, Maryland, USA). A total of 8 points were placed along the LV lateral wall contoured from anterolateral to inferolateral septum and the interventricular septum contoured from RV insertion point to RV insertion point.…”

“…In particular CMR derived interventricular septal curvature, which provides a quantitative assessment of the interventricular septum throughout the cardiac cycle, has been associated with mean pulmonary artery pressure and pulmonary vascular resistance in adult and pediatric patients [ 17 , 21 – 24 ]. However, no studies have assessed the relationship of septal curvature with PH in the BPD population.…”

Noninvasive pulmonary artery wave intensity analysis in pulmonary hypertension

“…It may be particularly useful in situations where diagnostic indictors such as septal curvature (23) are less reliable (i.e., patients with PH related to complex congenital heart disease). Nevertheless, this was not a diagnostic cohort study and further work must be performed to evaluate true diagnostic accuracy.…”

Left ventricular diastolic dysfunction in pulmonary hypertension predicts functional capacity and clinical worsening: a tissue phase mapping study

“…Transmitral E and A wave peaks were measured from the mitral valve inflow PCMR data, allowing calculation of E/A ratio. Septal curvature was assessed using the midventricular short axis cine images, as described previously [ 19 ].…”