Plasma total calcium concentration is associated with blood pressure and systemic vascular resistance in normotensive and never-treated hypertensive subjects

Abstract

2020) Plasma total calcium concentration is associated with blood pressure and systemic vascular resistance in normotensive and never-treated hypertensive subjects, Blood Pressure, 29:3, 137-148, ABSTRACT Purpose: The underlying causes of primary hypertension are not fully understood. Evidence on the relation of plasma calcium concentration with blood pressure (BP) is inconsistent and relies largely on studies utilizing office BP measurements in populations using cardiovascular drugs. In many studies adjustment for confounders was not optimal. In this cross-sectional study we examined the association of plasma total calcium concentration with the haemodynamic determinants of blood pressure. Subjects and methods: Supine haemodynamics were recorded using pulse wave analysis, whole-body impedance cardiography, and heart rate variability analysis in 618 normotensive or never-treated hypertensive subjects (aged 19-72 years) without diabetes, cardiovascular or renal disease, or cardiovascular medications. Linear regression analysis was used to investigate factors associated with haemodynamic variables. Results: Mean age was 45.0 years, body mass index 26.8 kg/m 2 , seated office BP 141/89 mmHg, and 307 subjects (49.7%) were male. Mean values of routine blood and plasma chemistry analyses were within the reference limits of the tests except for low-density lipoprotein cholesterol (3.05 mmol/l). In the laboratory, mean supine radial BP was 131/75 mmHg, and both systolic and diastolic BP correlated directly with plasma total calcium concentration (r ¼ 0.25 and r ¼ 0.22, respectively, p < 0.001 for both). In regression analysis plasma total calcium concentration was an independent explanatory variable for radial and aortic systolic and diastolic BP, and systemic vascular resistance, but not for cardiac output, pulse wave velocity, or any of the heart rate variability parameters. Conclusion: Plasma total calcium concentration was directly associated with systolic and diastolic BP and systemic vascular resistance in normotensive or never-treated hypertensive subjects without comorbidities and cardiovascular medications. Higher plasma calcium concentration potentially plays a role in primary hypertension via an effect on vascular resistance. ARTICLE HISTORY

Aldosterone-to-renin ratio is related to arterial stiffness when the screening criteria of primary aldosteronism are not met

“…Changes in calcium metabolism may influence BP 60 , and induce alterations in the components of the reninangiotensin system in the vasculature 61 . Moreover, vitamin D receptor activation downregulates the synthesis of renin in the juxtaglomerular cells and influences the expression of other components of the renin-angiotensin system in the kidney 62,63 .…”

Parathyroid hormone may play a role in the pathophysiology of primary hypertension

“…We recently found that plasma total calcium concentration was directly linked to the level of BP via elevated systemic vascular resistance (SVR) in normotensive and hypertensive subjects without antihypertensive agents [22]. In the present cross-sectional study we examined whether plasma PTH, a key regulator of calcium levels [23], is associated with central BP and its haemodynamic determinants in 622 normotensive or never-treated hypertensive subjects, who had plasma PTH and calcium concentrations predominantly within the normal range.…”

“…Subjects were selected from an ongoing investigation on haemodynamics in primary and secondary hypertension (DYNAMIC study, clinical trial registration NCT01742702), currently comprising 1349 subjects. The enrolment has been previously described [22]. The study was approved by the ethics committee of the Tampere University Hospital (code R06086M) and the Finnish Medicines Agency (Eudra-CT number 2006-002065-39), and it complies with the Declaration of Helsinki.…”

“…Blood and urine samples were collected after ~12 hours of fasting. The detailed protocol for laboratory analyses has been described previously [22]. The reference range for plasma intact PTH in our laboratory is 1.6-6.9 pmol/l, and for plasma total calcium 2.15-2.51 mmol/l.…”

“…Prior to the recordings the participants were directed to abstain from caffeine, smoking, and heavy meals for ≥4 hours, and from alcohol for ≥24 hours. Beat-to-beat supine haemodynamic data was recorded for 5 minutes, followed by 5 minutes of passive head-up-tilt [25] according to a previously described protocol [22]. The mean values of each minute during the 10-minute recording were calculated for statistics.…”