Evaluation Of Pulmonary Hypertension With CMR:Control Study With Healthy Volunteers And Evaluation Of Pulmonary Arterial Hypertension Severity And Prognosis

Objective The aim of this study is to investigate the application value in PH diagnosis and to evaluate PAH severity and prognosis by the combined use of Cardiac Magnetic Resonance(CMR) parameters.Methods(1)FIESTA Cine-MRI and phase-contrast(PC) MRI were performed in 56 PH patients collected from Tianjin Medical University General Hospital from January2012 to December 2014 and 22 healthy controls. FIESTA images were post-processed and the following parameters were calculated: left ventricle(LV), right ventricle(RV)end-systolic volume(ESV), end-diastolic volume(EDV), ejection fraction(EF),stroke volume(SV), cardiac output(CO), myocardial mass(MM), RV end-diastolic area(EDA),RV end-systolic area(ESA), RV fractional area change(RVFAC),tricuspid annular plane systolic excursion(TAPSE), interventricular septal curvature(CIVS), left ventricular free wall curvature(CFW), curvature ratio(RC)=CIVS/CFW and ventricular mass index(VMI). RV, LV EDV, ESV, SV, MM were normalized by body surface area(BSA) as: RV, LV EDVI, ESVI, SVI and MMI. MPA positive peak velocity, maximal area, minimal area and distensibility were measured by using PC-MRI images. Student t-tests was used to compare CMR measurements between PH patients and controls. Receiver operating characteristic(ROC) curve analysis was used to compare the PH diagnostic abilities for four important parameters(MPA positive peak velocity, distensibility, RC, and RVFAC) and combined CMR parameter.P<0.05 was considered significant.(2) FIESTA images of 47 PAH patients were post-processed and the CMR parameters were calculated to predict the mortality.According to the endpoint whether patients have adverse event or not, all enrolled patients were classified into two groups Adverse Event Group and NO Adverse Event Group. The baseline condition was noted and compared between 2 groups and the follow-up outcomewas analized by ROC curves and Cox regression survival analysis.Results(1)Comparing to healthy controls, RVEDVI, RVESVI, RVMMI, maximal and minimal area of MPA were significantly higher in the PH group(P?0.001), while RVEF, RVFAC, RC, positive peak velocity and distensibility of MPA were significantly lower in the PH group(P?0.001). The ROC curve analysis showed that,among the four parameters, distensibility of MPA had the highest AUC value(AUC=0.95, Sensitivity= 87.5%, Specificity= 95.5%). Additionally, combined CMR parameter(MPA positive peak velocity+ distensibility+ RC+ RVFAC) had even higher AUC(AUC=0.988), and the sensitivity was 94.6% and specificity was 100.0%.(2)At baseline, CMR measurements were closely related with mean pulmonary artery hypertension(m PAP), diatolic pulmonary artery hypertension(d PAP) and systolic pulmonary artery hypertension(s PAP). At follow-up, compared to NO Adverse Event Group, RVEF, TAPSE, LVSVI were significantly lower in the Adverse Event Group,while VMI was significantly lower in the NO Adverse Event Group(P?0.05). ROC analysis identified the VMI had the highest AUC value(AUC= 0.819) predicting adverse event for the study, with a sensitivity of 69.2% and a specificity of85.3%.Additionally, RVEF, TAPSE predicted the adverse event with the same higher degree of sensitivity(84.5%). Based on cut-off value of 29.08 ml/m2, the specificity for LVSVI prediction in PAH mortality was 91.2%. According to Kaplan-Meier survival curves, survival was lower in patients with RVEF <30.15(%), TAPSE<15.8(mm), LVSVI<29.08(ml/m2), and VMI>0.76.Conclusion CMR could provide both anatomy and hemodynamics noninvasively for PH diagnosis. Moreover, the combined use of different types of CMR parameters,which synthesized the morphological and functional information, could possibly improve the diagnostic accuracy in the clinics. Then, RVEF, TAPSE, LVSVI and VMI assessed with CMR predict outcomes in patients with PAH. A reduced RVEF, TAPSE,LVSVI and a large VMI are strong predictors of mortality and severity.