Evaluation of pulmonary artery stiffness in pulmonary hypertension with cardiac magnetic resonance.
OBJECTIVE
This study sought to evaluate indexes of pulmonary artery (PA) stiffness in patients with pulmonary hypertension (PH) using same-day cardiac magnetic resonance (CMR) and right heart catheterization (RHC).


BACKGROUND
Pulmonary artery stiffness is increased in the presence of PH, although the relationship to PH severity has not been fully characterized.


METHODS
Both CMR and RHC were performed on the same day in 94 patients with known or suspected PH. According to the RHC, patients were classified as having no PH (n = 13), exercise-induced PH (EIPH) only (n = 6), or PH at rest (n = 75). On CMR, phase-contrast images were obtained perpendicular to the pulmonary trunk. From CMR and RHC data, PA areas and indexes of stiffness (pulsatility, compliance, capacitance, distensibility, elastic modulus, and the pressure-independent stiffness index beta) were measured at rest.


RESULTS
All quantified indexes showed increased PA stiffness in patients with PH at rest in comparison with those with EIPH or no PH. Despite the absence of significant differences in baseline pressures, patients with EIPH had lower median compliance and capacitance than patients with no PH: 15 (interquartile range: 9 to 19.8) mm2/mm Hg versus 8.4 (interquartile range: 6 to 10.3) mm2/mm Hg, and 5.2 (interquartile range: 4.4 to 6.3) mm3/mm Hg versus 3.7 (interquartile range: 3.1 to 4.1) mm3/mm Hg, respectively (p < 0.05). The different measurements of PA stiffness, including stiffness index beta, showed significant correlations with PA pressures (r2 = 0.27 to 0.73). Reduced PA pulsatility (<40%) detected the presence of PH at rest with a sensitivity of 93% and a specificity of 63%.


CONCLUSIONS
Pulmonary artery stiffness increases early in the course of PH (even when PH is detectable only with exercise and before overt pressure elevations occur at rest). These observations suggest a potential contributory role of PA stiffness in the development and progression of PH.
Clinical Cardiac MR/CT Program, Zena and Michael A. Wiener Cardiovascular Institute and Marie-Josee and Henry R. Kravis Center for Cardiovascular Health, Mount Sinai School of Medicine, New York, New York 10029, USA. Javier.Sanz@mssm.edu
Javier
J
Sanz
Mbabazi
M
Kariisa
Santo
S
Dellegrottaglie
Susanna
S
Prat-González
Mario J
MJ
Garcia
Valentin
V
Fuster
Sanjay
S
Rajagopalan
D000328:Adult; D000368:Aged; D001794:Blood Pressure; D006328:Cardiac Catheterization; D018450:Disease Progression; D004548:Elasticity; D005080:Exercise Test; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000473:pathology* / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011651:Pulmonary Artery / Q000473:pathology* / Q000503:physiopathology; D011673:Pulsatile Flow; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index