Left ventricular (LV) hypertrophy is a major risk factor for cardiovascular morbidity. This study examined the extent to which exaggerated blood pressure (BP) reactivity is associated with LV mass and relative wall thickness (RWT) in a large sample of middle-aged hypertensive men and women. Participants included 1,012 African-Americans and 655 Caucasians recruited for the Hypertension Genetics Epidemiology Network (HyperGEN) study. A laboratory stress protocol was implemented, consisting of BP measurement during rest, handgrip, and a mental arithmetic stressor. This was followed by a 2-dimensional guided M-mode echocardiographic evaluation to measure LV mass. LV mass was greater among African-Americans relative to Caucasians (p <0.01). Systolic BP at rest was positively associated with LV mass and RWT in African-Americans (p <0.001) and in Caucasian women (p <0.0001). LV mass and RWT were compared in participants and participants were classified as high or low reactors based on their systolic BP responses to the 2 laboratory stressors. RWT demonstrated positive associations with systolic BP responses to both tasks. Associations with LV mass were mostly nonsignificant with the exception of a negative association in African-Americans between systolic BP responses to the arithmetic task and LV mass. We conclude that in this cohort of hypertensive middle-aged men and women, BP reactivity did not predict LV mass. Positive associations of systolic BP responses with RWT suggest that exaggerated reactivity may particularly be related to LV changes influenced by vascular tonus.
Bibliographical noteFunding Information:
Hypertensive participants were recruited for the Hypertension Genetic Epidemiology Network Study (HyperGEN) project (n = 1,676). The HyperGEN is a project funded by the National Heart, Lung, and Blood Institute (Bethesda, Maryland) to examine genetic and environmental determinants of hypertension in 5 population-based samples. Participants in the present study included 671 African-American women, 350 African-American men, 336 Caucasian women, and 319 Caucasian men. Eligibility criteria for hypertensives included an average untreated BP >140/90 mm Hg from multiple measurements during ≥1 visit before being enrolled in the study. Pretreatment BP was obtained from the physician, clinic, or hospital where the participant was treated. Participants were asked to bring all medications during their clinic visit, and medication names and doses were recorded. Current medications were coded and combined into classes (e.g., diuretics and so forth). History of hypertension was obtained through documenting dates or ages of initial onset, and dates or ages when medication began. Exclusion criteria included age of hypertension onset of >60 years and hypertension secondary to primary kidney disease or pregnancy. Participants signed informed consent forms approved by the respective institutional review boards.
This study was supported by the HyperGEN grants HL54473 (St. Louis, Missouri DCC), HL54496 (Minneapolis, Minnestoa Field Center), HL54472 (Minnesota Central Blood Lab), HL54515 (Utah Molecular Genetics Lab), HL54495 (Birmingham, Alabama Field Center), HL54497 (Framingham, Massachusetts Field Center), HL54471 (Salt Lake City, Utah Field Center), and HL54509 (Forsyth County, North Carolina Field Center), and National Institute of Health Grant M10RR0047-34 (GCRC), Bethesda, Maryland.