TY - JOUR
T1 - Magnetic resonance imaging analysis of right ventricular pressure-volume loops
T2 - In vivo validation and clinical application in patients with pulmonary hypertension
AU - Kuehne, Titus
AU - Yilmaz, Sevim
AU - Steendijk, Paul
AU - Moore, Phillip
AU - Groenink, Maarten
AU - Saaed, Maythem
AU - Weber, Oliver
AU - Higgins, Charles B.
AU - Ewert, Peter
AU - Fleck, Eckard
AU - Nagel, Eike
AU - Schulze-Neick, Ingram
AU - Lange, Peter
PY - 2004/10/5
Y1 - 2004/10/5
N2 - Background - The aims of this study were to validate MRI-derived right ventricular (RV) pressure-volume loops for assessment of RV myocardial contractility and then to apply this technique in patients with chronic RV pressure overload for assessment of myocardial contractility, ventricular pump function, and VA coupling. Methods and Results - Flow-directed catheters were guided under MR fluoroscopy (1.5 T) into the RV for invasive pressure measurements. Simultaneously, ventricular volumes and myocardial mass were assessed from cine MRI. From sampled data, RV pressure-volume loops were constructed, and maximal ventricular elastance indexed to myocardial mass (E max_i) was derived by use of a single-beat estimation method. This MRI method was first validated in vivo (6 swine), with conductance techniques used as reference. Bland-Altman test showed good agreement between methods (E max_i=5.1±0.5 versus 5.8±0.7 mm Hg · mL -1 · 100 g -1, respectively; P=0.08). Subsequently, the MRI method was applied in 12 subjects: 6 control subjects and 6 patients with chronic RV pressure overload from pulmonary hypertension. In these patients, indexes of RV pump function (cardiac index), E max_i, and VA coupling (E max/E a) were assessed. In patients with pulmonary hypertension, RV pump function was decreased (cardiac index, 2.2±0.5 versus 2.9±0.4 L · min -1 · m -2; P<0.01), myocardial contractility was enhanced (E max_i, 9.2±1.1 versus 5.0±0.9 mm Hg · mL -1 · 100 g -1; P<0.01), and VA coupling was inefficient (E max/E a, 1.1±0.3 versus 1.9±0.4; P<0.01) compared with control subjects. Conclusions - RV myocardial contractility can be determined from MRI-derived pressure-volume loops. Chronic RV pressure overload was associated with reduced RV pump function despite enhanced RV myocardial contractility. The proposed MRI approach is a promising tool to assess RV contractility in the clinical setting.
AB - Background - The aims of this study were to validate MRI-derived right ventricular (RV) pressure-volume loops for assessment of RV myocardial contractility and then to apply this technique in patients with chronic RV pressure overload for assessment of myocardial contractility, ventricular pump function, and VA coupling. Methods and Results - Flow-directed catheters were guided under MR fluoroscopy (1.5 T) into the RV for invasive pressure measurements. Simultaneously, ventricular volumes and myocardial mass were assessed from cine MRI. From sampled data, RV pressure-volume loops were constructed, and maximal ventricular elastance indexed to myocardial mass (E max_i) was derived by use of a single-beat estimation method. This MRI method was first validated in vivo (6 swine), with conductance techniques used as reference. Bland-Altman test showed good agreement between methods (E max_i=5.1±0.5 versus 5.8±0.7 mm Hg · mL -1 · 100 g -1, respectively; P=0.08). Subsequently, the MRI method was applied in 12 subjects: 6 control subjects and 6 patients with chronic RV pressure overload from pulmonary hypertension. In these patients, indexes of RV pump function (cardiac index), E max_i, and VA coupling (E max/E a) were assessed. In patients with pulmonary hypertension, RV pump function was decreased (cardiac index, 2.2±0.5 versus 2.9±0.4 L · min -1 · m -2; P<0.01), myocardial contractility was enhanced (E max_i, 9.2±1.1 versus 5.0±0.9 mm Hg · mL -1 · 100 g -1; P<0.01), and VA coupling was inefficient (E max/E a, 1.1±0.3 versus 1.9±0.4; P<0.01) compared with control subjects. Conclusions - RV myocardial contractility can be determined from MRI-derived pressure-volume loops. Chronic RV pressure overload was associated with reduced RV pump function despite enhanced RV myocardial contractility. The proposed MRI approach is a promising tool to assess RV contractility in the clinical setting.
KW - Heart defects, congenital
KW - Hypertension, pulmonary
KW - Magnetic resonance imaging
KW - Myocardial contraction
KW - Ventricles
UR - http://www.scopus.com/inward/record.url?scp=20844453067&partnerID=8YFLogxK
U2 - 10.1161/01.CIR.0000143138.02493.DD
DO - 10.1161/01.CIR.0000143138.02493.DD
M3 - Article
C2 - 15451801
AN - SCOPUS:20844453067
SN - 0009-7322
VL - 110
SP - 2010
EP - 2016
JO - Circulation
JF - Circulation
IS - 14
ER -