Maia Akopian

Long-Term Effects of Parathyroidectomy on Hypertension Prevalence and Circadian Blood Pressure Profile in Primary Hyperparathyroidism

Our aims were to evaluate the prevalence and outcome of hypertension in patients with primary hyperparathyroidism (PHPT), previously and after follow-up of parathyroidectomy. A group of 46 consecutive patients with sporadic PHPT due to adenoma undergoing surgery were followed an average of 3.5 years (range 36 to 53 months). In 16 nonselected, consecutive parathyroidectomized patients, with normalized biochemical measurements, circadian rhythm of blood pressure was evaluated with ambulatory blood pressure monitoring (ABPM). Prevalence of hypertension in PHPT was 54.35%, and there was no significant association of PTH, total and ionic calcium levels with SBP and DBP. During follow-up, none of the patients with presurgical hypertension became normotensive and five of the normotensive patients developed clinical hypertension. In ABPM, 6/11 hypertensive and 3/5 normotensive subjects showed nondipper behavior. Serum total calcium was significantly related to night-time systolic blood pressure (SBP) (r = 0.620, P < 0.02), and night-time diastolic blood pressure (DBP) (r = 0.758, P < 0.002). In dippers, creatinine clearance was significantly higher (91.3 ± 18.5 vs. 64.3 ± 11.5 ml/min, P < 0.01), while serum total calcium was lower (2.42 ± 0.13 vs. 2.23 ± 0.17 mmol/L, P < 0.04) than in nondippers. In conclusion, our results suggest that parathyroidectomy has little effect on hypertension prevalence. Renal impairment, a condition that did not improve after parathyroidectomy, may be a causal factor of hypertension in PHPT. Also, the high prevalence of nondipper behavior in hypertensive and normotensive subjects after parathyroidectomy, suggests that target organ risk persists. We hypothesized that slight elevations of serum total calcium even in the normal range could be involved in the alteration of the circadian rhythm of blood pressure.

Association between nondipper behavior and serum calcium in hypertensive patients with mild-to-moderate chronic renal dysfunction.

A nondipping BP pattern has been shown to be predictive of end-organ damage, cardiovascular events, and mortality. The mechanisms of blunted nocturnal BP fall are multifactorial. We assessed whether total corrected serum calcium and ionic calcium (iCa) are associated with a blunted nocturnal BP fall in both treated and untreated hypertensive patients with stages 1–3 of the National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF KDOQI). Clinical data and 24-hour ambulatory blood pressure monitoring were obtained in a cohort of 231 essential hypertensive patients. Among the entire cohort, 107 were nondippers and 124 were dippers. Only in nondippers, we found significant correlations between iCa and 24-hour systolic blood pressure (SBP; r = 0.21, P < .03), diurnal SBP (r = 0.21, P < .03), and 24-hour pulse pressure (PP; r = 0.23, P < .02). The ambulatory arterial stiffness index (AASI) was significantly related with 24-hour PP in both dippers and nondippers after adjusting for age. Both AASI and 24-hour PP were higher in nondippers than in dippers. In addition, in nondippers, the prevalence of estimated glomerular filtration rate (eGFR) <60 mL/minute/1.73 m2 was higher than in dippers (50% vs. 33.7%, P < .02). Logistic regression showed that patients with eGFR ≥60 mL/minute/1.73 m2 had lower risk of nondipper status than patients with eGFR <60 mL/minute/1.73 m2 (odds ratio = 2.445; 95% confidence interval = 1.398–4.277, P < .002). In conclusion, serum iCa could participate in the pathogenesis of nondipping pattern. Increased large artery stiffness may be a mechanism of the deleterious influence of nondipping on cardiovascular outcome. Hypertensive subjects with stage 3 of NKF KDOQI had a greater loss of circadian BP rhythm than those in stages 1 and 2.

Relationship between Hyperinsulinemia and Ambulatory Blood Pressure Monitoring of Lean and Overweight Male Hypertensives

Objective To elucidate the role of hypertension as part of a state of insulin resistance. Methods Thirty-one uncomplicated hypertensive men not receiving antihypertensive treatment or who had been without treatment for a 4-week washout period and 10 lean normotensive controls were compared. Hypertensive men were divided according to their body mass index into three groups. All subjects came to the clinic for measurements of height, weight, hip and waist circumferences, and sitting blood pressure, and to begin 24 h ambulatory blood pressure monitoring. Plasma glucose and insulin levels were measured during a 2 h oral glucose (75 g)-tolerance test. For the hypertensive population as a whole, behaviors of studied variables among dippers (n= 18) and nondippers (n= 13) were determined. Results During oral glucose-tolerance testing blood glucose levels after 60 min and 120 min were significantly higher (P < 0.05) in members of the high body mass index group than they were in members of the low body mass index group. insulin levels of members of the high and middle body mass index groups were higher than those of members of the low body mass index group after 60 min (P < 0.05 for both comparisons) and 120 min (P < 0.05 for both comparisons). The mean serum insulin level in members of the low body mass index group was significantly higher than that in normotensives after 30 min, 60 min and 120 min (P < 0.05 for all three comparisons). The mean serum insulin: Plasma glucose ratio for men in the low BMI group was significantly higher than that for normotensives after 60 min and 120 min (P < 0.05 for both comparisons). Correlations of blood pressure and insulin levels were not significant. Levels of high-density lipoprotein cholesterol and triglycerides were lower in members of the group with high body mass index than they were in members of the group with low body mass index. Total cholesterol: High-density lipoprotein cholesterol ratio was higher for members of the high body mass index group than it was for members of the middle body mass index group. Weight, body mass index, casual systolic blood pressure, 24 h average systolic blood pressure and diastolic blood pressure, 0700-2300 h systolic blood pressure, and 24 h average heart rate-systolic blood pressure product of dippers were significantly lower than those of nondippers. Conclusions These results suggest that hypertension and being overweight have additive effects increasing insulinemia and that being overweight is associated with a significantly lower nocturnal fall in blood pressure. J Cardiovasc Risk 5: 25-30

Insulin resistance in non-obese and overweight essential hypertensives from an urban population in Argentina

To determine the prevalence of insulin resistance/hyperinsulinemia and other components of the metabolic syndrome among non-obese, and obese essential hypertensives living in Buenos Aires. One hundred thirtyone hypertensives never treated or after 3 week placebo period and 31 normotensive control subjects matched for age, sex and BMI, that demonstrated normal glucose tolerance at the OGTT were included. The plasma fasting insulin (IRI) levels, the SIRI (the sum of the plasma insulin levels after the OGTT), and the Homa’s index of the groups were compared. In non-elderly (aged 65 y) hypertensives the mean insulin value (AUCinsulin), SIRI and the AUCglucose were higher than in agedmatched normotensives (81.2 67.2 vs 53.3 34.3 m U/ml; 273.1 230.7 vs 185.8 113.8 m U/ml, and 133.4 29.1 vs 121.8 18.6 mg/dl, respectively, for all p 0.05). In non-elderly non-obese hypertensives AUCinsulin was higher than in agedsexand weight-matched normotensives (61.5 42 vs 37.2 17.6 m U/ml, p 0.05). In overweight hypertensive men the AUCinsulin and SRI were higher than in non-obese (81.3 64.1 vs 46.9 34.1 m U/ml; 275.7 222.4 vs 164.3 122.4 m U/ml, both p 0.05). Multiple logistic regression analysis showed age, gender and waist circumference (WC) were associated with risk of hypertension (OR: 1.05; 4.5; 4.6, respectively). Only hypertensives in the third tertile of AUCinsulin had higher triglyceride levels than those in the lower tertile (p 0.05). Hypertensives with larger WC (men 102, women 88 cm) had higher triglycerides (166.4 70 vs 121,7 42.5 mg/dl, p 0.01); AUCglucose (150.6 32.4 vs 126,.8 24.4 mg/dl, p 0.01); AUCinsulin (107.8 88.2 vs 63.8 40.5 m U/ml, p 0.05) and SIRI (368.3 305.6 vs 213.4 135.3 m U/ml, p 0.01) than those with normal WC. In hypertensives IRI levels and HOMA were correlated with daytime DBP and 24-h mean DBP (p 0.05). These data suggest that insulin resistance may contribute to the pathogenesis of hypertension. It is likely that visceral fat distribution and genetic factors contribute to the increased prevalence of insulin resistance in hypertension in this urban population.