Real Time Magnetic Resonance Assessment of Septal Curvature Accurately Tracks Acute Hemodynamic Changes in Pediatric Pulmonary Hypertension
Background—This study assesses the relationship between septal curvature and mean pulmonary artery pressure (mPAP) and indexed pulmonary vascular resistance (PVRi) in children with pulmonary hypertension. We hypothesized that septal curvature could be used to estimate right ventricular (RV) afterload and track acute changes in pulmonary hemodynamics.
Methods and Results—50 patients with a median age of 6.7 (range 0.45-16.5 years) years underwent combined cardiac catheterization and cardiovascular magnetic resonance (CMR). 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). mPAP and PVR was acquired at baseline and during vasodilation. Septal curvature was measured using real time CMR. There was a strong correlation between mPAP and SCmin at baseline and during vasodilator testing (r = -0.81 and -0.85 respectively p<0.01). A strong linear relationship also existed between PVR and minimum septal curvature indexed to cardiac output both at baseline and during vasodilator testing (r = -0.88, r = -0.87 respectively p<0.01). Change in septal curvature metrics moderately correlated with absolute change in mPAP and PVR respectively (r=0.58, r=-0.74 P<0.01). Septal curvature metrics were able to identify vasoresponders with a sensitivity of 83% (95% CI 0.36 - 0.99), the specificity was 91% (95% CI 0.77 - 0.97), employing the Sitbon criteria. IPAH subgroup analysis revealed three responders with ΔSCmin values of 0.523, 0.551 and 0.568. If the middle value of 0.551 is taken as a cut-off, the approximate sensitivity would be 67%, the specificity would be 93%.
Conclusions—Septal curvature metrics are able to estimate RV 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.
- septal curvature
- pulmonary hypertension
- cardiac magnetic resonance imaging
- Received September 9, 2013.
- Accepted April 16, 2014.