Effect Of Arterial Stiffness On Myocardial Work In Hypertensive And Non-hypertensive Subjects

Hypertension is a serious disease which deeply threatens our human health and brings a huge global economic burden.Long-term elevated blood pressure can lead to left ventricular remodeling and dysfunction,eventually leading to heart failure.To explore the changes and mechanisms of early left ventricular cardiac function induced by hypertension,and to identify individuals who are likely to develop serious heart injury,may play a positive role in the early prevention and control of hypertension-induced heart failure.myocardial work(MW)derived from left ventricular pressure-strain loop via ultrasonic two dimensional speck tracking technology is a new noninvasive method to evaluate the cardiac function and reflect the ventricular-arterial coupling.Arteriosclerosis is not only an important pathological change of hypertension,but also an important structural basis for the maintenance and aggravation of blood pressure.Therefore,the purpose of this study aimed to study the application value of this non-invasive new method in hypertension patients with left ventricular ejection fraction(LVEF)preserved,and to explore the effect of arteriosclerosis on MW.PART 1 STUDY DESIGN AND SUBJECT RECRUITMENTObjective : To study the application value of noninvasive MW in hypertension and to explore the effect of arteriosclerosis on MW in this study population.Methods: A prospective single-center cross-sectional observational study was designed.Hypertensives and non-hypertensives aged 18-65 years were included in the study.All participants underwent conventional echocardiography,speck-tracking echocardiography to assess MW and strain,and brachial-ankle pulse wave velocity(ba PWV)measurements.According to the different study purpose,non-hypertensive subjects were divided into normal blood pressure and normal high blood pressure subgroups,and hypertensive population was divided into stage 1hypertension and stage 2 hypertension subgroups.Results:A total of 208 subjects were eventually enrolled.Among them,104 were hypertensives and 104 were non-hypertensives.Of the 104 patients with hypertension,56 received antihypertensive medications and48 did not;There were 34 subjects with stage 1 hypertension and 70 with stage 2 hypertension.Among 104 non-hypertensive subjects,69 had normal blood pressure and 35 had normal high blood pressure.The median age of the overall study population was 49.0(42.0-56.0)years,with 114(54.8%)males.Conclusion: The purpose of this study was to investigate the application of noninvasive MW in the assessment early left ventricular performance in hypertension,and to explore the effect of atherosclerosis on myocardial work by using ba PWV as an indicator of atherosclerosis.This study has certain clinical value and significance.PART 2 MYOCARDIAL WORK IN DIFFERENT BLOOD PRESSURE POPULATIONObjective: To study the effect of blood pressure load on the myocardial work of people with different levels of blood pressure.Methods: This part of the study included 118 subjects.Of them,35 were normal blood pressure,35 were normal high blood pressure,21 were stage 1 hypertension,and 27 were stage 2 hypertension.None of the hypertensive patients received antihypertensive medications.The 35 with normal blood pressure were randomly selected from over all normal blood pressure study population.4 components of MW named global work index(GWI),global constructive work(GCW),global wasted work(GWW)and global work efficiency(GWE).ANOVA or Kruskal-Wallis test was used to compare the difference in myocardial work among people with different blood pressure levels.Results: The mean value of GWI was 1781.34 ± 228.61 mm Hg%,2001.74 ± 282.09 mm Hg%,2092.29 ± 307.68 mm Hg% and 2140.93 ±351.20 mm Hg%,respectively,in the normal blood pressure group,the normal high blood pressure group,the stage 1 hypertension group and the stage 2 hypertension group.GWI,GCW and GWW increased with the increase of blood pressure levels,while GWE decreased with the increase of blood pressure levels,and the difference among these four groups were statistically significant.Myocardial work parameters in the with normal high blood pressure group were significantly different from those with normal blood pressure,while global longitudinal strain(GLS)remained unchanged.Conclusion: Noninvasive MW can reflect the early changes of cardiac function in patients with different levels of blood pressure,it is a reliable method for evaluating early cardiac function impairment in hypertensives.In normal high blood pressure subjects,myocardial work can detect myocardial function changes earlier than GLS.PART 3 NON-INVASIVE GLOBAL MYOCARDIAL WORK INDEX AS A SURROGATE OF VENTRICULAR–ARTERIAL COUPLING IN HYPERTENSIVE PATIENTS WITH PRESERVED LEFT VENTRICULAR EJECTION FRACTIONObjective: As a new method of left ventricular-arterial coupling(VAC),non-invasive myocardial work index(MWI)may provide more useful information than the classical methods of arterial elastance/left ventricular elastance index(Ea/Ees).The aim of this study was to investigate whether MWI could be better associated with hypertension-mediated organ damage(HMOD)and diastolic dysfunction than Ea/Ees in hypertension.Methods: 104 hypertensives and 69 normotensives were analyzed in this part of study.Global work index(GWI)is a component of myocardial work.Correlation between GWI and HMOD,as well as diastolic dysfunction were analyzed.Predicting ability of GWI was analyzed by receiver operating characteristic(ROC)curve.Results: GWI was significantly higher in hypertensives than in normotensives(2021.69 ± 348.02 mm Hg% vs 1757.45 ± 225.86 mm Hg%,respectively,P<0.001).Higher GWI was independent risk factor of increased ba PWV,pulse pressure(PP)and left atrial volume index(LAVI),and echocardiographic left ventricular hypertrophy(LVH)(P = 0.023,P<0.001,P =0.007,P = 0.002,respectively),after adjustment for age,sex and mean arterial pressure.However,no significant associations were observed between Ea/Ees and HMOD parameters and markers of diastolic dysfunction.The area under ROC curve of GWI for predicting increased PP and ba PWV,echocardiographic LVH and increased LAVI were 0.799,0.770,0.674 and 0.679,respectively(all P < 0.05).Conclusions: GWI but not traditionally echocardiographic-derived Ea/Ees of VAC is independently related to HMOD and diastolic impairment in hypertensives with preserved left ventricular ejection fraction.GWI maybe a novel promising marker to assess VAC in hypertension.PART 4 IMPACT OF BRACHIAL-ANKLE PULSE WAVE VELOCITY ON MYOCARDIAL WORK BY NON-INVASIVE LEFT VENTRICULAR PRESSURE-STRAIN IN NON-HYPERTENSIVE AND HYPERTENSIVE PATIENTS WITH PRESERVED LEFT VENTRICULAR EJECTION FRACTIONObjective: Data regarding the influence of arterial stiffness on myocardial work(MW)has been scarce.This study was performed to investigate the association between brachial-ankle pulse wave velocity(ba PWV)and MW by non-invasive left ventricular pressure–strain in a population of non-hypertensive and hypertensive individuals.Methods: 208 participants(104 hypertensive and 104non-hypertensive individuals)were analyzed in this part of study.Participants were categorized according to ba PWV tertiles.Correlation between ba PWV and MW were analyzed.Predicting ability of ba PWV for abnormal MW was analyzed by receiver operating characteristic(ROC)curve.Results: The median ba PWV from low to high tertile group were1286.5(1197.5-1343.5)cm/s,1490.0(1444.5-1544.0)cm/s and 1803.8(1708.3-1972.0)cm/s,respectively.In simple linear regression analysis,ba PWV had a significant positive association with global work index(GWI),global constructive work(GCW)andglobal wasted work(GWW)and a negative association with global work efficiency(GWE).The association remained significant after adjusted major confounding factors in multiple linear regression analysis.The area under ROC curve of ba PWV for predicting abnormal GWI,GCW and GWW and GWE were 0.653,0.666,0.725 and 0.688,respectively(all P < 0.05).Conclusions: Ba PWV is significantly associated with GWI,GWE,GCW and GWW of MW by non-invasive left ventricular pressure-strain method in a mixed population of non-hypertensive and hypertensive individuals with LVEF preserved.