| Objective:Turner syndrome(TS)is a sex chromosomal disorder caused by complete or partial deletion of an X chromosome in all or some cells,or structural abnormality of X chromosome.About 50%of patients with Turner syndrome(TS)have congenital or acquired cardiovascular lesions.Aortic abnormalities in TS mainly include aortic dilatation,aortic dissection,bicuspid aortic valve and aortic coarctation,abnormal pulmonary venous drainage,abnormal heart murphy and function.Aortic dissection is considered to be the most important factor for abnormal death.Early and comprehensive evaluation of cardiovascular damage as well as the search for clinical factors closely related to cardiovascular damage will improve the diagnosis and outcome of patients.At present,echocardiography is the main method for cardiovascular system evaluation,but its reproducibility and effectiveness have some challenges.Cardiac magnetic resonance(CMR)is the gold standard for evaluating cardiac structure and function.However,there is no study on the evaluation of cardiac remodeling and myocardial strain in TS by CMR.There are still insufficient studies on the correlation between cardiac,the types and severity of aortic lesions,and clinical complications in TS patients.Therefore,the main purposes of this study were as follows:1.Using CMR technology to evaluate the left ventricular structure and function in TS,and to explore the risk factors that may be related to them.2.Evaluating the location and type of aortic defects in TS and the relationship between them,evaluating the differences in cardiac morphology and function in dilated or coarctation patients,in order to reveal the correlation and clinical value between aorta and cardiac function.3.Using CMR to evaluate the murphy,function and its related clinical factors of pulmonary artery and right ventricle in Turner,in order to provide evidence for early clinical intervention,and improve the prognosis of patients.Materials and Methods:This study prospectively included 41 patients with Turner’s syndrome in our hospital from October 2019 to February 2021,and 30 volunteers with matched age and gender enrolled as control group.The clinical data were collected.All patients were divided into 45X and others according to karyotype,and all patients were divided into growth hormone treated group(GN+group)and untreated group(GN-group)according to the situation of growth hormone replacement therapy,all patients were divided into autoimmune thyroiditis positive group and negative group.In the first part,CMR cine was used to evaluate left ventricular geometry,function and mass of participants.Tissue tracking was used to analyze myocardial strain,including global peak radial strain(GPRS),global peak circumferential strain(GPCS)and global peak longitudinal strain(GPLS),the strain parameters of the three directions mentioned above in the basal,middle and apex segments were also analyzed.The difference and relationship of clinical parameters,left ventricular structure,function and strain between Turner group,control group and subgroups were analyzed.In the second part,the CMR cine and aortic imaging sequence were used to evaluate the internal diameter of aorta,seven layers including sinuses of valsalva,sinotubular junction,ascending aorta,proximal aortic arch,distal aortic arch,isthmus and descending aorta were evaluated.Body surface area(BSA)normalization and Z score were used to determine the aortic diameter.All patients were divided into dilated and non-dilated group,coarctation and non-coarctation group according to the diameter of aorta.The differences of clinical characteristics,aortic dimension,left ventricular structure and function,and strain between Turner group and control group and each subgroup were compared.The consistency of different standardized methods in evaluating ascending aortic dilatation was analyzed,and the clinical and imaging factors related to aortic dilatation or coarctation were analyzed.In the third part,CMR cine and pulmonary artery imaging sequence were used to evaluate left ventricular geometry and pulmonary artery diameter in TS group.The differences of right ventricular structure and function,myocardial strain and pulmonary artery diameter between Turner group,control group and clinical subgroups were compared.The clinical and imaging factors that may affect right ventricular function and pulmonary artery diameter were analyzed in order to obtain a clinical predictor of image features.Results:The average height of Turner group was significantly lower than that of normal group(132.8±17.4cm vs 144.9±16.8cm,P=0.004).The heart rate(93.6±12.5 bp/min vs 85.7±12.9 bp/min,P=0.013)and systolic blood pressure(110.2±11.7 mm Hg vs 95.6±19.2 mm Hg,P<0.001)of Turner were higher than those of normal group.The main results of first part were as follows:The relative wall thickness(RWT)(0.12±0.02 vs 0.10±0.02,P=0.008)and left ventricular mass index(LVmassi)were significantly higher than that of normal group(43.8±8.7 vs39.8±4.9,P=0.030).The global(global:-14.7±2.7 vs-17.2±2.5,P<0.001)and segmental(basal:-12.9±3.2 vs-15.3±3.4,P=0.004;middle:-13.4±3.3 vs-16.0±3.3,P=0.001;apical:-18.1±2.6 vs–19.8±2.6,P=0.006)longitudinal strain were significantly lower than those of normal group.RWT,Mass/EDV,RI,LVmassi and left ventricular ejection fraction(LVEF)had no significant difference in different karyotypes and GN subgroups.RWT was positively correlated with EF(r=0.535,P<0.001),and positively correlated with GPLS(r=0.470,P=0.002).The uterine development of TS patients was slightly positively correlated with left ventricular RI(r=0.281,P<0.031).The main results of second part were as follows:The diameter of ascending aorta(BSA method:20.7±4.4 mm/m~2 vs 18.2±3.2 mm/m~2,P=0.010;Z score:1.2±1.7 vs 0.1±0.8,P=0.003)in Turner group were significantly higher than those in control group.In the diagnosis of dilatation of ascending aorta,there was no significant difference between BSA method and Z score(P=0.063),and strong consistency between the two methods(kappa=0.738,P<0.001)were found.The incidence of aortic dilatation was the highest in ascending aorta(29.3%),followed by the sinuses of valsalva and sinotubular junction(14.6%),and coarctation mainly occurred in isthmus(14.6%).Ascending aortic dilatation(Z score>2.0)was positively correlated with the diameter of sinuses of valsalva,sinotubular junction and proximal aortic arch(r=0.44-0.60,P<0.05).Aortic coarctation(Z score<-2.0)was negatively correlated with distal aortic arch diameter(r=-0.54,P<0.05).The GPLS in dilation group was significantly lower than that in the non-dilation group(BAS method:-13.4±2.0 vs-15.0±2.3,P=0.040;Z score:-13.7±1.9 vs-15.2±2.4,P=0.040).Ascending aortic dilatation had moderately correlated with 45X karyotype(r=-0.33,P=0.035).Ascended aorta dilatation or coarctation had no correlation with age,thyroid function,growth hormone and chromosome karyotype(P>0.05).The main results of third part were as follows:The right ventricular ejection fraction(RVEF)(62.4±8.9%vs 55.4±4.7%,P<0.001),end-systolic elastance/effective arterial elastance(Ees/Ea)(1.8±0.7 vs 1.3±0.3,P<0.001)and Z score of main pulmonary artery(0.5±0.9 vs-0.4±0.8,P<0.001)in TS were significantly higher than that in control group.The right ventricle global longitudinal peak strain(RVGPLS)was lower than that of the control group(-12.7±2.4 vs-15.1±4.2,P=0.005).The autoimmune thyroiditis positive group and negative group:there were no statistical differences in Eea/Ea,right ventricular functional and Z score of main pulmonary artery(P>0.05).GN+group and GN-group:RVGPLS in GN-group was significantly lower than that in GN+group(-11.0±1.3 vs-14.0±-2.2,P<0.05).RVEF,Ees/Ea and diameter of main pulmonary artery had no statistical difference between these two subgroups.45X and other karyotypes:The RVEF,Ees/Ea and Z score of main pulmonary artery in 45X and other karyotypes groups were higher than that in normal control group(P<0.05),but no significant difference were found between subgroups.The diameter of main pulmonary artery was positively correlated with RVEF(r=0.379,P=0.014)and Ees/Ea(r=0.371,P=0.017).Conclusion:TS patients were shorter than normal people,the heart rate,but the blood pressure and mass of left ventricular were higher.The existence of left ventricular GPLS injury indicated subclinical myocardial systolic disfunction.Different genotypes and growth hormone replacement therapy had no significant effect on left ventricular morphology and function.The aortic dilatation involved multiple segments of aortic in TS,with the highest incidence of the ascending aorta.Aortic dilatation was associated with left ventricular strain injury,suggesting that aortic dilatation is not only a risk factor for dissection,but also a potential factor for left ventricular functional injury.Therefore,in the process of diagnosis,treatment and follow-up of TS patients,the morphology and development of ascending aorta should be paid close attention to,and appropriate intervention treatment may benefit both heart and aorta.The reduction of GPLS in right ventricular and the pulmonary artery widen in TS indicated that under the effect of a variety of primary and secondary factors,the cardiovascular system may experience right heart dysfunction and pulmonary arterial hypertension risk,the application of recombinant growth hormone may improve right ventricular dysfunction of subclinical stage,in the process of TS treatment and follow-up,it is necessary to think globally,and comprehensive imaging evaluation is of great value for the judgment of prognosis and the optimization of treatment strategy. |
