The Assessment Of Left Ventricular Myocardial Deformation In Essential Hypertension Patients By Using Cardiovascular Magnetic Resonance Feature Tracking

Background and ObjectiveEssential hypertension is defined as a rise in blood pressure which can increase risks for cerebral,cardiac,and renal events with unknown reason.Hypertension remains deserving for more attention since it is a potent risk factor for cardiovascular diseases and it brings considerable morbidity and mortality.Early identifying subclinical left ventricular systolic dysfunction among hypertensive subjects might have an important role in assessing the prognosis and choosing treatment strategies.Strain imaging has emerged as a sensitive and powerful tool to detect early and subclinical myocardial dysfunction in various cardiac diseases,and may provide a novel method for LV risk assessment in hypertensive patients.The aims of the study were to identify subclinical systolic function abnormalities and evaluate influencing factors associated with left ventricular（LV）strain parameters in essential hypertension using cardiovascular magnetic resonance imaging feature tracking（CMR-FT）.Materials and MethodsThe study prospectively enrolled 57 patients with essential hypertension（mean age:43.04±10.90 years;35 males）and 26 healthy volunteers（mean age:38.69±10.44years;11 males）.The hypertensive patients had normal EF（≥50%）.Hypertension was defined as a history of hypertension,use of antihypertensive medicines,or the values≥130 mmHg SBP（Systolic Blood Pressure）and/or≥80 mmHg DBP（Diastolic Blood Pressure）according to the 2017 clinical practice guidelines of the American College of Cardiology/American Heart Association task force.Clinical and laboratory data were also obtained.Cine images were acquired using a standard balanced steady state free precession（bSSFP）sequence on 3.0 T MRI scanner.The analysis of routine cardiac function and myocardial strain of left ventricular（LV）was performed using CVI⁴22 post-processing software.Comparisons of the differences of general information,clinical data,laboratory findings,LV routine cardiac function parameters and myocardial strain parameters between the hypertensive patients and the controls were performed by using independent-sample Student’s t test,Mann-Whitney U test or Chi square test.Univariable and multivariable linear regression analyses were performed to assess factors of association with LV strain parameters.For intra-and inter-observer agreements of strain and strain rate parameters,intra-class correlation coefficient（ICC）and Bland-Altman plots were calculated.ResultsCompared with controls,hypertensive patients had significantly impaired myocardial strains and strain rates while ejection fraction（EF）did not differ(GRS（GlobalRadialStrain）:35.14±7.27%VS42.14±7.80%;GCS（Global CircumferentialStrain）:-19.64±2.46%VS-21.87±2.42%;GLS（Global Longitudinal Strain）:-16.48±2.34%VS-17.85±1.83%;SSRR_MAX（Radial Systolic Maximum Strain Rate）:1.65±0.27 VS 1.92±0.38 S^-1;SSRC_MAX（Circumferential Systolic Maximum Strain Rate）:-0.92±0.16 VS-1.05±0.14 S^-1;SSRL_MAX（Longitudinal Systolic Maximum Strain Rate）:-0.77±0.15 VS-0.95±0.13 S^-1;all P<0.05.EF:63.19±6.18%VS 65.42±4.13%;P=0.056).In univariable linear regression analyses in the hypertensive population,reduced GRS,GCS and GLS were all associated with MAP（β=-0.331,0.121,and 0.09,respectively,all P<0.05）and left ventricular mass index（LVM/BSA）（β=-0.366,0.125,and 0.081,respectively,all P<0.05）.After multivariate regression analyses adjustment for confounders including age,sex,BSA,high density lipoprotein cholesterol（HDLC）and LVM/BSA,the associations with MAP remained significant for LV myocardial strain parameters（GRS,GCS and GLS）.In multivariable regression models,the GRS was independently associated with the mean arterial pressure（MAP）and LVM/BSA（β=-0.219,P=0.009 andβ=-0.224,P=0.015,respectively;Adjusted R²=0.4）;the GCS was also independently associated with the MAP and LVM/BSA（β=0.084,P=0.002 andβ=0.073,P=0.01,respectively;Adjusted R²=0.439）;the GLS was independently associated with the Age and MAP（β=0.065,P=0.021 andβ=0.077,P=0.009,respectively;Adjusted R²=0.289）.Reproducibility was good with intra-and inter-observer intra-class correlation coefficient（ICC）of>0.75 for strain and strain rate parameters.The reproducibility of strain parameters was better than that of strain rate parameters.Conclusion1.Myocardial strain can early detect the myocardial damage and may be an appropriate target for preventive strategies because it occurs before abnormalities of EF.2.Among essential hypertensive patients,increased MAP may have an adverse effect on LV myocardial strains.3.CMR-FT may have potential to quantitatively analyze cardiac motion and apply in routine clinical practice in the future.