Exercise- and hypoxia-induced blood flow through intrapulmonary arteriovenous anastomoses is reduced in older adults.

Autor:	Norris HC; Department of Human Physiology, University of Oregon, Eugene, Oregon; and., Mangum TS; Department of Human Physiology, University of Oregon, Eugene, Oregon; and., Duke JW; Department of Human Physiology, University of Oregon, Eugene, Oregon; and., Straley TB; Department of Human Physiology, University of Oregon, Eugene, Oregon; and., Hawn JA; Oregon Heart and Vascular Institute, RiverBend, Springfield, Oregon., Goodman RD; Oregon Heart and Vascular Institute, RiverBend, Springfield, Oregon., Lovering AT; Department of Human Physiology, University of Oregon, Eugene, Oregon; and lovering@uoregon.edu.
Jazyk:	angličtina
Zdroj:	Journal of applied physiology (Bethesda, Md. : 1985) [J Appl Physiol (1985)] 2014 May 15; Vol. 116 (10), pp. 1324-33. Date of Electronic Publication: 2014 Mar 13.
DOI:	10.1152/japplphysiol.01125.2013
Abstrakt:	Mean pulmonary arterial pressure (Ppa) during exercise is significantly higher in individuals aged ≥50 yr compared with their younger counterparts, but the reasons for this are unknown. Blood flow through intrapulmonary arteriovenous anastomoses (IPAVA) can be detected during exercise or while breathing hypoxic gas mixtures using saline contrast echocardiography in almost all healthy young individuals. It has been previously hypothesized that a lower degree of exercise-induced blood flow through IPAVA is associated with high Ppa during exercise. This association may suggest that individuals who are known to have high Ppa during exercise, such as those ≥50 yr of age, may have lower blood flow through IPAVA, but the presence and degree of exercise-induced blood flow through IPAVA has not been specifically studied in older populations. Using transthoracic saline contrast echocardiography, we investigated the potential effects of age on exercise-induced blood flow through IPAVA in a cross-section of subjects aged 19-72 yr. To verify our findings, we assessed the effects of age on hypoxia-induced blood flow through IPAVA. Age groups were ≤41 yr (younger, n = 16) and ≥50 yr (older, n = 14). Qualitatively measured exercise- and hypoxia-induced blood flow through IPAVA was significantly lower in older individuals compared with younger controls. Older individuals also had significantly higher pulmonary arterial systolic pressure and total pulmonary resistance (TPR) during exercise. Low blood flow through IPAVA was independently associated with high TPR. The reasons for the age-related decrease in blood flow through IPAVA are unknown. (Copyright © 2014 the American Physiological Society.)
Databáze:	MEDLINE
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