4 research outputs found
a cardiovascular magnetic resonance study
Background The hypertensive deoxy-corticosterone acetate (DOCA)-salt-treated
pig (hereafter, DOCA pig) was recently introduced as large animal model for
early-stage heart failure with preserved ejection fraction (HFpEF). The aim of
the present study was to evaluate cardiovascular magnetic resonance (CMR) of
DOCA pigs and weight-matched control pigs to characterize ventricular, atrial
and myocardial structure and function of this phenotype model. Methods Five
anesthetized DOCA and seven control pigs underwent 3 T CMR at rest and during
dobutamine stress. Left ventricular/atrial (LV/LA) function and myocardial
mass (LVMM), strains and torsion were evaluated from (tagged) cine imaging. 4D
phase-contrast measurements were used to assess blood flow and peak
velocities, including transmitral early-diastolic (E) and myocardial tissue
(E’) velocities and coronary sinus blood flow. Myocardial perfusion reserve
was estimated from stress-to-rest time-averaged coronary sinus flow. Global
native myocardial T1 times were derived from prototype modified Look-Locker
inversion-recovery (MOLLI) short-axis T1 maps. After in-vivo measurements,
transmural biopsies were collected for stereological evaluation including the
volume fractions of interstitium (VV(int/LV)) and collagen (VV(coll/LV)).
Rest, stress, and stress-to-rest differences of cardiac and myocardial
parameters in DOCA and control animals were compared by t-test. Results In
DOCA pigs LVMM (p < 0.001) and LV wall-thickness (end-systole/end-diastole, p
= 0.003/p = 0.007) were elevated. During stress, increase of LV ejection-
fraction and decrease of end-systolic volume accounted for normal
contractility reserves in DOCA and control pigs. Rest-to-stress differences of
cardiac index (p = 0.040) and end-diastolic volume (p = 0.042) were
documented. Maximal (p = 0.042) and minimal (p = 0.012) LA volumes in DOCA
pigs were elevated at rest; total LA ejection-fraction decreased during stress
(p = 0.006). E’ was lower in DOCA pigs, corresponding to higher E/E’ at rest
(p = 0.013) and stress (p = 0.026). Myocardial perfusion reserve was reduced
in DOCA pigs (p = 0.031). T1-times and VV(int/LV) did not differ between
groups, whereas VV(coll/LV) levels were higher in DOCA pigs (p = 0.044).
Conclusions LA enlargement, E’ and E/E’ were the markers that showed the most
pronounced differences between DOCA and control pigs at rest. Inadequate
increase of myocardial perfusion reserve during stress might represent a
metrics for early-stage HFpEF. Myocardial T1 mapping could not detect elevated
levels of myocardial collagen in this model. Trial registration The study was
approved by the local Bioethics Committee of Vienna, Austria
(BMWF-66.010/0091-II/3b/2013)