Evaluation Of Right Ventricular Contractile Pattern And Prognosis By Echocardiography Following Heart Transplant

Part 1 Evaluation of Right Ventricular Contractile Pattern by Echocardiography Following Heart TransplantObjectives: The right ventricular(RV)contractile pattern may be different post-heart transplant(HT),which rendered the use of normal values derived from healthy subjects unsatisfactory in the transplanted hearts.Therefore,this study aimed to:(1)assess the change of RV contraction pattern after HT;(2)further establish the specific reference values of RV function for HT patients using echocardiography.Methods: A total of 530 study subjects who underwent echocardiography at our institution between January 2018 and December 2019 were prospectively enrolled,including 330 patients post-HT(HT group),100 patients after other cardiac surgeries(CS group),and 100 healthy volunteers(healthy control).The clinical information was collected for all study subjects.The parameters of the RV contractile pattern were evaluated by echocardiography.The RV global systolic function was evaluated by RV fractional area change(RV FAC);RV longitudinal systolic function was evaluated by tricuspid annular plane systolic excursion(TAPSE),tricuspid lateral annular systolic velocity(S’),longitudinal FAC(LFAC),LFAC/FAC,RV free wall longitudinal strain(FWLS),and RV global longitudinal strain(GLS);RV transverse systolic function was evaluated by transverse FAC(TFAC)and TFAC/FAC using echocardiography.The parameters of the RV contractile pattern were compared among the HT group,CS group,and healthy control.And the reference ranges of RV function were derived from 95 th percentiles.Results:(1)The RV FAC was lower in the HT group than in the CS group and healthy control,but still within the normal range(44.7 ± 4.7% vs 47.6 ± 4.8% vs 49.6 ± 4.5%,P < 0.001).(2)The RV longitudinal systolic function were decreased(including TAPSE,S’,LFAC,LFAC/FAC,RV FWLS,and RVGLS,P < 0.001 for all),and transverse systolic function was increased significantly(including TFAC,and TFAC/FAC,both P < 0.001)in HT cohorts than in CS group and healthy controls.(3)With respect to the normal reference values of RV function,there was no significant difference of RV FAC between the HT cohorts and the published guideline for healthy control(36% vs 35%).However,all measurements of RV longitudinal systolic function were reduced(TAPSE: 9mm vs 16mm;S’: 6 cm/s vs 10cm/s;RV FWLS:-14% vs-23%;RVGLS:-12% vs-20%)in HT cohorts than in the published guideline for normal hearts.Conclusions: There are major differences in the RV contractile pattern in subjects after HT,with a dramatic reduction in longitudinal contraction and relative increase in transverse shortening despite normal global RV function.The specific reference values for the RV function of HT subjects were further established.The normative values were lower for RV systolic function performed with longitudinal methods in HT cohorts than in the published guideline for normal hearts.Our data may foster the implementation of the specific reference values of RV systolic function after HT in clinical practice.And further assist in the accurate assessment of RV function,and guide the follow-up and management of patients post-HT.Part 2 Echocardiographic Assessment of Right Ventricular Function Score for Predicting Adverse Clinical Events after Heart TransplantObjectives: Numerous right ventricular(RV)systolic function parameters have been recognized as an important predictor of adverse outcomes in various cardiovascular diseases.However,the study about the prognostic value of RV systolic function after heart transplant(HT)was scarce.And it is not clear whether there is an incremental prognostic advantage in combining several RV function parameters.Therefore,the study aimed to(1)explore the prognostic value of various RV systolic function parameters;(2)further combine several RV systolic function parameters to develop a simple RV function score(RVFS)of adverse clinical events post-HT using echocardiography.Methods: A total of 357 consecutive HT recipients who underwent echocardiography between January 2018 and December 2019 at our institution were prospectively included.The clinical information pre-,intra-,and post-HT of all HT patients were collected.RV systolic function was evaluated by RV fractional area change(RV FAC),tricuspid annular plane systolic excursion(TAPSE),tricuspid lateral annular systolic velocity(S’),RV free wall longitudinal strain(FWLS),and RV global longitudinal strain(GLS)using echocardiography.The patients were prospectively followed up from the time of echocardiography,and the adverse events were recorded.The multivariate Cox hazard model was performed to identify the independent predictors of RV function for adverse clinical events in HT recipients.And receiver operating characteristic(ROC)curves were performed to identify their best cutoff values.Then the RVFS was derived by assigning the value of 1 to each independent predictor when it’s above the cutoff value,and 0 when it’s below the cutoff value,and then by summing the number.And the comparison between different models was made using the C statistic,the integrated discrimination improvement(IDI),and the net reclassification improvement(NRI).Results:(1)A total of 357 patients after HT were included in the study.After a median follow-up period of 39(29,42)months,the composite of adverse clinical events occurred in 51 patients.(2)The HT patients with adverse events showed significantly lower RV systolic function than patients without adverse events: RV FAC(39.2 ± 5.7% vs 44.7 ± 4.8%,P < 0.001),TAPSE(13.7 ± 2.9mm vs 15.2 ± 3.2mm,P = 0.002),RV FWLS(-15.9 ± 2.4% vs-19.1 ± 3.3%,P < 0.001),and RVGLS(-14.6 ± 2.3% vs-16.7 ± 2.9%,P < 0.001).(3)The multivariate COX regression analysis showed that RV FAC [hazard ratio(HR): 0.872;95% confidence interval(CI): 0.829 to 0.917;P < 0.001],TAPSE(HR: 0.890;95% CI: 0.812 to 0.976;P = 0.014),and RV FWLS(HR: 1.267;95% CI: 1.143 to 1.404;P < 0.001)were all the independent significant predictors of adverse events in HT recipients.(4)And ROC curves were performed to identify the optimal cutoff values of the independent RV function predictors.Then the RVFS was constructed based on these 3 parameters by assigning the value of 1 to each independent predictor when it’s above the cutoff value,and 0 when it’s below the cutoff value,and then by summing the number,ranging from 0 to 3 points.And the ROC curves showed that the accuracy for predicting adverse events was greater for the RVFS than separate RV function parameters(area under the curve: 0.84 vs 0.64~0.78,P < 0.05).(5)Furthermore,adding the RVFS to the base clinical model improved the C index(from 0.74 to 0.81,P < 0.0001),and yield an absolute IDI of 0.177(P < 0.001),and a continuous NRI of 0.462(P < 0.001).Conclusions: The RV FAC,TAPSE,and RV FWLS by echocardiography all were the independent significant predictors of adverse events after HT.Furthermore,the RVFS,an easily obtainable echo score,which combined several RV function parameters,improved the prediction of outcomes over separate RV systolic function parameters and baseline clinical prognostic factors in HT patients.Therefore,it is suggested that the application of RVFS may offer good discrimination of adverse outcomes,and provide an important basis for risk stratification and hierarchical management of patients after HT in clinical.