Luis M. Mayorga

Magnesium Plus nifedipine: Potentiation of hypotensive effect in preeclampsia?

Two women with preeclampsia treated unsuccessfully with alpha-methyldopa and magnesium sulfate became profoundly hypotensive when oral nifedipine was added. Blood pressure returned to previous levels without changes in fetal vitality. Awareness of this potentiation is important because nifedipine is being used increasingly in the treatment of pregnancy-related hypertension.

Diastolic Pressure Underestimates Age-Related Hemodynamic Impairment

It has been hypothesized that as large arteries become more rigid with age, the pattern of hypertension changes from diastolic to systolic. Thus, diastolic blood pressure (DBP) may lose its ability to reflect the increase in vascular resistance with age. To assess this, we studied the age-related changes in blood pressure pattern and its steady-state and pulsatile determinants. We performed an epidemiological analysis based on a national survey of 10,462 subjects from Argentina. A hemodynamic analysis (impedance cardiography) was then carried out in 636 consecutive hypertensive patients (age, 25 to 74 years). Whereas the rate of increment in the prevalence of mild to moderate hypertension (MMH) reached a plateau after the sixth decade, isolated and borderline systolic forms of hypertension began a steep and sustained rise. Among patients with MMH, DBP remained stable from the third to the seventh decade, whereas SBP maintained a sustained increase. Despite similar DBP, the systemic vascular resistance index increased 47% (P<.01) and the cardiac index decreased 27% (P<.01), whereas the ratio of stroke volume to pulse pressure, an index of arterial compliance, decreased 45% (P<.01). However, there were no significant differences between older patients with MMH and those with isolated systolic hypertension in the level of SBP, vascular resistance, stroke volume, and cardiac index. Compared with age-matched normotensive control subjects, the ratio of stroke volume to pulse pressure was much more reduced in isolated systolic hypertension (48%) than in MMH (30%). In summary, the present study, carried out in a large sample of hypertensive subjects with a wide age range, showed a simultaneous impairment in vascular resistance and arterial compliance associated with aging in different patterns of hypertension. The magnitude of these changes, with opposite effects on DBP but additive effects on SBP, suggests that a hemodynamic mechanism could determine the transition in the prevalence of diastolic hypertension toward a systolic pattern of hypertension with aging. Also, the results suggest that SBP, but not DBP, is a reliable indicator of the underlying hemodynamic abnormalities (high resistance and low arterial compliance) in the elderly.

Lack of effective blood pressure control among an elder hypertensive population in Buenos Aires.

Our purpose was to determine the level of awareness, treatment, and control of hypertension in a population of subjects aged 65 or more. We studied a random sample from the national health care program in Buenos Aires. Letters were mailed to 1000 selected individuals. Among those eligible, 41.4% (n = 414) were enrolled. The mean age was 73.8 years and 68% were women. Prevalence of hypertension in our sample was 77.5% (n = 321). Awareness of hypertension was 60.7% (n = 195). Fifty-four percent (n = 173) of the hypertensive subjects were receiving pharmacologic treatment and only 18.5% (n = 32) of them were controlled. These results show that there is a low level of awareness, pharmacologic treatment, and control of hypertension in the studied elderly subjects.

Prevalence of hyperhomocysteinemia in an elderly population

BACKGROUND Currently, total hyperhomocysteinemia (tHHcy) is a well-known condition linked to a higher risk of vascular disease. Prevalence of HHcy increases in elderly persons as the risk associated with it persists. Because factors can be potentially reduced in the elderly, it is important to carry out epidemiologic studies of HHcy. PROCEDURE Previously we described the prevalence of hypertension control in an elder population; now, in an observational cross-sectional simple blind study, total homocysteine (tHcy) concentration was determined in 196 of 400 patients from the original cohort. RESULTS Mean Hcy concentration was 13.2 ,amol/L (95% confidence interval 12.4-14.0; range, 5.0 to 48.9); 15.0 ,imol/L for men and 12.3 pAmol/L for women. Mean serum folic acid levels were 4.9 + 3.1 ng/mL (range, 2.0 to 20.0 ng/mL), and vitamin B12 levels were 384.8 314.1 pg/mL (range, 48.0 to 1500.0 pg/mL). Taking into account the reference values established by the Third National Health and Nutrition Examination Survey III study, HHcy was detected in 69.8% of all the subjects evaluated. The study showed that 76.2% of the men and 66.4% of the women had high Hcy levels. CONCLUSIONS The very high prevalence of tHHcy in the elderly population, and the consequent risks associated with it suggest that although there are no trials that effectively prove the benefit of tHcy decrease, nutritional intervention is still justified.