Correlation between central aortic stiffness indices and cardiac mechanics in hypertensive patients: new insights from speckle tracking echocardiography imaging

Abstract

Abstract Background Left ventricular (LV) and left atrial (LA) mechanics are altered in hypertensive patients. Recent evidence suggests that central aortic pressure, rather than brachial pressure is strongly related to future cardiovascular events. Currently, oscillometric non-invasive devices are considered a reliable method for estimation of central aortic pressure and stiffness indices. Purpose To evaluate the relation between central aortic pressure measured using oscillometric non-invasive device and cardiac mechanics assessed by speckle tracking echocardiography (STE). Methods Fifty hypertensive patients with apparently structural normal heart were consecutively enrolled. A new oscillometric device was programmed to measure blood pressure over a period of 30 minutes (total of 15 sequential readings) and then data was transferred to a computer-based software where the central aortic pressure and stiffness indices (Augmentation index {AIx} and Pulse wave velocity {PWV}) were automatically calculated. All patients underwent conventional transthoracic echocardiography and STE. STE analysis of LV and LA functions was done using a specific software. LV systolic (global longitudinal strain {GLS}) as well as diastolic (measured at peak mitral filling {E} and at isovolumetric relaxation time {IVRT}) strain/strain rate were measured. LA strain was measured during reservoir (LASr), conduit (LAScd) and contraction (LASct) phases. Results The mean age was 45.9±10.6 years and 38% of patients were males. Most of the population was overweight with mean BMI 28±1.9 kg/m2. About 2/3 of population has uncontrolled hypertension (mean brachial systolic and diastolic blood pressure was 139.8±17.5 and 88.4±11.3 mmHg, respectively). The mean central systolic (cSBP) and diastolic blood pressures (cDBP) were elevated (122.2±13.3 and 84.6±10.8 mmHg, respectively). cSBP and cDBP showed significant weak negative correlation with LV diastolic strain rate (Dsr) at peak E (cSBP: r=−0.33, p=0.02; cDBP: r=−0.28, p=0.04). There was no significant correlation between LV GLS and central stiffness indices (p>0.05). cDBP was significantly negatively correlated with LASct (r=−0.3, p=0.03), with no other significant correlation between central stiffness indices and other LA functions (LASr and LAScd) (p>0.05). Conclusions Changes in LV diastolic strain/strain rate parameters assessed by STE are related to central aortic pressure particularly cSBP and cDBP in patients with hypertension. This relation was also observed with LA strain parameters namely LASct. Funding Acknowledgement Type of funding sources: None.