Integrated Assessment of Diastolic and Systolic Ventricular Function Using Diagnostic Cardiac Magnetic Resonance CatheterizationValidation in Pigs and Application in a Clinical Pilot Study
Boris Schmitt, MD*,*,
Paul Steendijk, PhD ,
Karsten Lunze, MD*,
Stanislav Ovroutski, MD*,
Jan Falkenberg, MD*,
Pedram Rahmanzadeh, MD*,
Nizar Maarouf, MD*,
Peter Ewert, MD, PhD*,
Felix Berger, MD, PhD*,
Titus Kuehne, MD, PhD*
* Department of Congenital Heart Disease and Pediatric Cardiology, Deutsches Herzzentrum Berlin, Berlin, Germany
Departments of Cardiology and Cardiothoracic Surgery, Leiden University Medical Center, Leiden, the Netherlands
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Figure 1 Time Line of the Study
The animals were first assessed at rest and during dobutamine administration using a conductance catheter technique. Then they were moved to the neighboring CMR laboratory and investigated again at rest and during dobutamine application. The figure shows the position of the catheters in the left and right ventricle and the inferior vena cava. The CMR was performed using a cine CMR method in the axial plane (shaded box in A) and by VEC CMR measurements in the aorta and the pulmonary truncus (arrow in B). CMR = cardiac magnetic resonance; EDPVR = end-diastolic pressure–volume relation; ESPVR = end-systolic pressure–volume relation; LV = left ventricle; RV = right ventricle; VEC = velocity-encoded cine.
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Figure 2 Baseline Pressure–Volume Loop at Steady-State Condition
The baseline loop (right) was constructed by synchronizing ventricular pressures with cine CMR–derived absolute volume data. The ESPVR was estimated from a single-beat approach. Pmax was calculated by a sinus wave extrapolation of the ventricular pressure curve. Further details are provided in the text. EDP = end-diastolic pressure; EDPV = end-diastolic pressure–volume point; EDV = end-diastolic volume; ESPV = end-systolic pressure–volume point; Pmax = maximum isovolumic ventricular pressure; Pv = pressure-volume; other abbreviations as in Figure 1.
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Figure 3 Composition of the Real-Time Pressure–Volume Loops From Simultaneously Measured Ventricular Pressure and Real-Time Velocity-Encoded Cine CMR–Derived Volume Data
Note that initially, end-diastolic volumes of all loops are unknown and were arbitrarily drawn equally spaced to better show the gradual decrease in end-diastolic pressure during unloading. Abbreviations as in Figures 1 and 2.
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Figure 4 Stepwise Arrangement of Baseline and Real-Time Pressure-Volume Loops for Assessment of EDPVR
The horizontal position of the real-time pressure–volume loops (lower left and Fig. 3) was calibrated by matching the end-systolic pressure–volume points with the ESPVR determined from the baseline pressure–volume loop (upper left and Fig. 2). The ESPVs of each beat were shifted to match to the intercept of the ESPVR at the corresponding pressure (middle). The EDPVR was determined by an exponential fit through the resulting EDPVs (right). Further details are given in the text. Abbreviations as in Figures 1 and 2.
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Figure 5 Comparison of Ventricular Stiffness Constant Measured by CC and by CMR
Bland-Altman plots show the difference between the results from conductance catheter (CC) and CMR measurements in 8 pigs for left and right ventricular stiffness constant (left, right). Measurements were performed at rest and during dobutamine and are shown in separate plots. In all plots there is a negative bias, which indicates a slight but consistent overestimation by CMR in both the left and the right ventricle. Abbreviations as in Figure 1.
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Figure 6 Changes in Stiffness Constant During Dobutamine Administration
Ventricular stiffness constants as measured with CMR and CC techniques in the pig left and right ventricle and in 3 patients with a single ventricle. There are no statistically significant differences between the CC and CMR measurements. In addition, this figure shows parallel decreases in the stiffness constant in CMR and CC measurements during dobutamine administration in pigs but no significant changes in Fontan patients. A value of p < 0.05 was considered significant. Abbreviations as in Figure 5.
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Figure 7 Ventricular Stiffness in the Healthy Animal Heart and in Fontan Patients
Representative CMR-derived pressure–volume loops of a pig right and left ventricle and a patient with a single ventricle. The end-systolic pressure–volume relation (ESPVR) and end-diastolic pressure–volume relation (EDPVR) at rest and during dobutamine administration are shown (left, dashed lines). The EDPVRs are shown more detailed (right). Note the left shift of the relation in the patient as opposed to the right-bottom shift in the pig's right and left ventricle during dobutamine administration. Abbreviations as in Figure 1.
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