Environmental determinants of blood pressure, arterial stiffness, and central hemodynamics

Arterial stiffness and wave reflection alterations may be implicated in the association between cardiovascular mortality, meteorological variables and ambient particulate matter air pollution. The present study explored the cross-sectional relations between ambient environmental parameters, arterial stiffness, peripheral and central hemodynamics in a large-scale cohort of hypertensive patients and normotensive controls.

The study comprised 1222 consecutive individuals who sought medical consultation in the hypertension outpatient clinics of the Hippokration' and 'Onassis' Hospitals (Athens, Greece) during a 3-year period (2004-2006). All individuals underwent a complete clinical and lipid-profile assessment at drug-free baseline. Carotid radial, carotid-femoral pulse wave velocity measurements and aortic pressure waveform analysis were performed noninvasively to all participants. Data from the National Technical University of Athens and the air quality department of the Hellenic Ministry for the Environment were used to estimate daily meteorological conditions and PM10 exposure.

In the total population, multiple-linear regression analysis revealed no significant associations between environmental variables and arterial stiffness. However, in men, the mean 5 day PM10 air concentration was independently associated with the augmentation pressure [2.0 mmHg (95% confidence interval (CI) 0.56-3.39) per 43.4 microg/m3] and the aortic-pulse pressure [2.78 mmHg (95% CI 3.91-5.12)] denoting a significant effect of particulate matter on the aortic-wave reflection magnitude and central hemodynamics. In addition, globally, the mean-daily temperature was related to the aortic-pulse pressure [-2.38 mmHg (95% CI -4.51 to -0.26) per 23.6 degrees C change] and the subendocardial viability ratio [5.85% (95% CI 1.1-10.6 per 23.6 degrees C)].

The exposure to lower environmental temperatures is related to impaired hemodynamics not only to the periphery but also to the aorta. In men, PM10 air-pollution levels are associated with heightened amplitude of the reflection wave leading to significant alterations in central-pulse pressure.