Assessment of ventricular-vascular coupling during exercise in hypertensive patients

Background: The ability of the heart to adequately respond to the increase of metabolic demand during exertion relies on several adaptive changes leading to augmented cardiac output without any rise of filling pressures. The impairment of these compensatory mechanisms, as found in various heart diseases including systemic hypertension, can translate to reduced functional capacity. In this study, we sought to investigate the cardiovascular adaptation to exertion in a cohort of asymptomatic hypertensive patients, with the aim to identify early cardiac abnormalities. Methods: We enrolled 54 subjects including 30 patients (45.1 ± 11.9 years, 19 males) and 24 age-matched healthy controls (44.4 ± 9.6 years, 14 males). A comprehensive echocardiographic and vascular evaluation, implemented by speckle-tracking imaging (STI) and echo-tracking analysis to assess, respectively, myocardial deformation and arterial stiffness, has been performed at rest and during exertion. Results There was a greater increase of E/E' from rest to peak exercise in patients than in controls (p = 0.014 and p = 0.087, respectively). Global longitudinal strain (GLS) of the left ventricle (LV) significantly increased from rest to peak stage in healthy subjects (p=0.011) whereas it remained unchanged in hypertensive patients (p = 0.777). In addition, LV untwist increased in both groups (p = 0.031 and 0.015 in patients and controls, respectively), with a minor increase in patients than in controls (p = 0.029 between groups, at peak stage). Left atrial (LA) reservoir was significantly increased, throughout the exercise, only in controls (p = 0.001) whereas it was almost unchanged in patients (p = 0.293. LA stiffness, calculated as the ratio between E/E' and LA reservoir, was significantly higher in patients than in controls both at rest (p=0.023) and during exercise (p < 0.001). Concerning vascular parameters, beta index and pulse wave velocity (PWV) by echo-tracking, increased during exercise in both groups, showing higher values in hypertensive patients in each step (p = 0.658 for beta index and p = 0.010 for PWV at peak stage; p = 0.004 for beta index and p < 0.001 for PWV during recovery. Conclusions: Exercise echocardiography implemented by STE and echo-tracking may be valuable in the early detection of cardiovascular abnormalities in asymptomatic hypertensive patients.