Early-stage heart failure with preserved ejection fraction in the pig: 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). © 2016 the author(s).