Variations of ambulatory blood pressure with position in patients with type 1 diabetes: influence of disease duration and microangiopathy in a pilot study

A study of the VaSera arterial stiffness device in US patients

The cardio-ankle vascular index (CAVI) represents a promising index of arterial stiffness. However, neither the CAVI measure nor its measurement device, the VaSera, have undergone general testing in a North American clinical setting. To begin the process of collecting normal values in the United States, we studied 20 male and 28 female volunteers without reported cardiovascular or renal disease and no history of smoking. Their CAVIs, ankle-brachial indices (ABIs), and four-limb blood pressures were measured in three positions: supine, 7° Trendelenburg, and 7° reverse Trendelenburg. In addition, the ABI function was validated against an established ABI measurement technique. Position was found to affect CAVI and other hemodynamic parameters, indicating that CAVI is not robust to slight positional variations. No differences were found in the blood pressure between arms or legs (interbrachial or interankle), supporting recent findings from meta-analyses and studies but contradicting other work. This study represents an early step in bringing the VaSera device and its CAVI measurement into clinical practice.

Out-of-office blood pressure: from measurement to control

Hypertension is an important risk factor for the development of cardiovascular disease, and is a major cause of morbidity and mortality worldwide. Traditionally, hypertension diagnosis and treatment and clinical evaluations of antihypertensive efficacy have been based on office blood pressure (BP) measurements; however, there is increasing evidence that office measures may provide inadequate or misleading estimates of a patient’s true BP status and level of cardiovascular risk. The introduction, and endorsement by treatment guidelines, of 24-hour ambulatory BP monitoring and self (or home) BP monitoring has facilitated more reliable and reproducible estimations of true BP, including the identification of white-coat and masked hypertension, and evaluation of BP variability. In addition, ambulatory BP monitoring enables accurate assessment of treatment effectiveness over 24 hours and both ambulatory and self BP monitoring may lead to better tailoring of therapy according to BP profile and concomitant disease. This review describes the clinical benefits and limitations of out-of-office assessments and their applications for effective management of hypertension and attainment of BP control.

Ambulatory blood pressure variations relative to sitting or standing position in renal transplant patients

OBJECTIVE

High blood pressure is almost constant in renal transplant patients for whom dysautonomia is frequently described. The main objective of this study was to analyse the variations in blood pressure and heart rate recorded by ambulatory measurement during changes in position in renal transplant patients.

METHODS

Thirty-nine non-diabetic renal transplant patients with a renal transplant functioning for more than a year, were selected at random. Blood pressure was measured using the validated monitor Diasys Integra with a position sensor to discriminate between standing and sitting/lying.

RESULTS

Systolic blood pressure and heart rate were significantly higher when the patient was standing than when sitting/lying (+2.9 mmHg, P<0.05 and +9 beats/min, P<0.001 respectively) and diastolic blood pressure tends to be higher (+1.7 mmHg, NS) when standing. One minute after standing up, the heart rate rises by about 9 beats/min (P<0.001) while systolic and diastolic blood pressures do not vary significantly. Variations in systolic blood pressure and heart rate on changing position are therefore in the same direction as those recorded in elderly normotensive or hypertensive untreated subjects, but with a lower amplitude.

CONCLUSIONS

In most of non-diabetic functional renal transplant patients, there is an absence of an orthostatic decline in blood pressure. Thus, it could be considered that there is no real dysautonomia in this specific population.