Background To evaluate changes in pulse pressure (PP) and markers of cardiovascular autonomic neuropathy (CAN) according to duration of type 1 diabetes mellitus (T1DM).

Introduction Squatting is an active posture test that can be used to assess baroreflex sensitivity. Indeed, the shift from squatting to standing imposes a major orthostatic stress leading to rapid and large changes in arterial blood pressure (BP) and heart rate (HR) allowing precise baroreflex assessment.

Treatment with rosiglitazone increased the production of thyroglobulin in some patients with thyroid cancers, but only rarely restored scintigraphically significant iodine trapping. It remains to be shown whether longer treatment periods might result in a more efficient redifferentiating effect.

OBJECTIVE -To evaluate pulse pressure changes according to duration of type 1 diabetes and to assess the influence of posture.RESEARCH DESIGN AND METHODS -We performed continuous measurement of blood pressure with a Finapres device during a 3 ϫ 1 min posture test (standing, squatting, standing) in 159 type 1 diabetic patients divided into four groups according to diabetes duration (Յ10, 11-20, 21-30, and Ͼ30 years, groups 1-4, respectively) and compared the results with those of age-matched nondiabetic subjects.RESULTS -Pulse pressure progressively increased according to type 1 diabetes duration (P Ͻ 0.0001), especially in women, but not in age-matched nondiabetic subjects (NS). Pulsepressure increase from group 1 to group 4 was amplified in the squatting position (from 50 Ϯ 17 to 69 Ϯ 14 mmHg) compared with standing (from 44 Ϯ 15 to 55 Ϯ 12 mmHg).CONCLUSIONS -Pulse pressure increases according to type 1 diabetes duration more in women than in men, and the squatting position sensitizes such pulse-pressure increase in both sexes.

word count = 225 words SUMMARYThe squatting test is an active posture manoeuvre that imposes one of the most potent orthostatic stresses. In normal subjects, the changes in blood pressure and heart rate are transient because of appropriate baroreflex homeostasis and do not provoke symptoms.However, in various pathological conditions, both the increase in blood pressure during squatting and the decrease in blood pressure during standing may be more important and sustained, potentially leading to complaints and adverse events. Squatting has been used to evaluate patients with tetralogy of Fallot, heart transplant, dysautonomia, including diabetic cardiovascular autonomic neuropathy, and individuals prone to vasovagal syncope. Careful analysis of changes in blood pressure and heart rate during the transition from standing to squatting and from squatting to standing allows the early detection of altered vagal and/or sympathetic function. Of note squatting position has been proposed as a therapeutic mean to counteract the fall in blood pressure in patients suffering from dizziness due to dysautonomia and orthostatic hypotension or presenting pre-syncope symptoms, such as soon after exercise.The aims of the present review are to analyse the haemodynamic pattern during a squatting test in various pathological situations and to describe what may be the negative and positive haemodynamic changes associated with this posture. We were especially interested in using the squatting test for the assessment of cardiovascular autonomic neuropathy associated with diabetes mellitus.

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Cardiovascular autonomic neuropathy (CAN) is a frequent complication of diabetes mellitus, which is associated with increased morbidity and mortality. It involves both the parasympathetic and sympathetic nervous systems, and may be diagnosed by classical dynamic tests with measurements of heart rate (HR) and/or arterial blood pressure (BP). An original squattest (1-min standing, 1-min squatting, 1-min standing) was used with continuous monitoring of HR and BP, using a Finapres ® device. This active test imposes greater postural stress than the passive head-up tilt test, and provokes large changes in BP and HR that can be analyzed to derive indices of CAN. In healthy subjects, squatting is associated with BP increases and HR decreases (abolished by atropine: SqTv index), whereas the squat-stand transition is accompanied by a deep but transient drop in BP associated with sympathetic-driven tachycardia (abolished by propranolol: SqTs index). In diabetic patients with CAN, BP increases are accentuated during squatting whereas reflex bradycardia is reduced. When standing from squatting position, the fall in BP tends to be more pronounced and orthostatic hypotension more prolonged, while reflex tachycardia is markedly dampened. The baroreflex gain, similar to that calculated during pharmacological testing with vasodilator/vasopressor agents, can be derived by plotting pulse intervals (R-R) against systolic BP levels during the biphasic response following the squat-stand transition. The slope, which represents baroreflex sensitivity, is significantly reduced in patients with CAN. This discriminatory index allows study of the natural history of CAN in a large cohort of diabetic patients.Keywords: Baroreflex sensitivity; Cardiovascular autonomic neuropathy; Finapres ; Squatting; Diabetes; Heart rate; Orthostatic hypotension; Posture test; Review RésuméTest postural d' accroupissement pour étudier la neuropathie autonome cardiovasculaire diabétique.La neuropathie autonome cardiaque (NAC) est une complication fréquente du diabète qui est associée à une augmentation de la morbidité et de la mortalité. Elle concerne à la fois les systèmes parasympathique et sympathique et peut être diagnostiquée classiquement par des tests dynamiques avec mesure des variations de la frequence cardiaque (FC) et de la pression artérielle (PA). Notre groupe a utilise un test postural original (1-min debout-1 -min accroupi ou « squatting »-1 -min debout) avec un monitorage continu de FC et PA avec un appareil Finapres ® . Ce test de redressement actif impose un stress postural plus prononcé que le test d'inclinaison passif sur une table basculante et provoque des variations amp les de PA et FC qui peuvent être analysées pour dériver des indices de NAC. Chez des sujets sains, le «squatting» entraîne une augmentation de PA et une diminution de FC (abolie par l'atropine : indice SqTv) alors que la transition accroupi-debout induit une chute importante mais transitoire de PA accompagnée d'une tachycardie d'origine sympathique (abolie par le ...

Aim. -Cardiovascular autonomic neuropathy (CAN) and pulsatile stress are considered to be independent cardiovascular risk factors. This study compared haemodynamic changes during an active orthostatic test in adult patients with type 1 diabetes (T1DM), using low versus high RR E/I ratios as a marker of CAN.Methods. -A total of 20 T1DM patients with low RR E/I ratios were compared with 20 T1DM patients with normal RR E/I ratios, matched for gender (1/1 ratio), age (mean: 46 years) and diabetes duration (22-26 years); 40 matched healthy subjects served as controls. All subjects were evaluated by continuous monitoring of arterial blood pressure (Finapres ® ) and heart rate using a standardized posture test (1-min standing, 1-min squatting, 1-min standing), thus allowing calculation of baroreflex gain.Results. -Compared with controls, T1DM patients showed lower RR E/I ratios, reduced baroreflex gains, higher pulsatile stress (pulse pressure × heart rate), greater squatting-induced pulse pressure rises, orthostatic hypotension and reduced reflex tachycardia. Compared with T1DM patients with preserved RR E/I ratios, T1DM patients with low RR E/I ratios showed reduced post-standing reflex tachycardia and baroreflex gain, and delayed blood pressure recovery, but no markers of increased pulsatile stress. Interestingly, decreased baroreflex gain was significantly associated with both pulsatile stress and microalbuminuria.Conclusion. -The use of RR E/I ratios to separate T1DM patients allows the detection of other CAN markers during an orthostatic posture test, but with no significant differences in pulsatile stress or microalbuminuria. In this context, squatting-derived baroreflex gain appears to be more informative. But. -La neuropathie autonome cardiaque (NAC) et le stress pulsatile sont considérés comme des facteurs de risque cardiovasculaire indépendants. Nous avons comparé les modifications hémodynamiques pendant un test actif d'orthostatisme chez des adultes diabétiques de type 1 (DT1) séparés selon la valeur de RR E/I ratio (basse versus élevée) comme marqueur de NAC. KeywordsMéthodes. -Vingt patients DT1 avec un ratio E/I abaissé ont été comparés à 20 patients DT1 avec un ratio E/I normal, appariés pour le sexe (1/1 ratio), l'âge (moyenne : 46 années) et la durée du diabète (22-26 années). Quarante sujets sains appariés ont servi de témoins. Tous les sujets ont été évalués par une mesure continue de pression artérielle (Finapres Résultats. -Comparés aux témoins, les patients DT1 ont un ratio E/I abaissé, un gain baroréflexe diminué, un stress pulsatile (pression puisée × fréquence cardiaque) accru, une augmentation plus marquée de pression puisée en position accroupie, une hypotension orthostatique et une tachycardie réflexe réduite. Comparés aux patients DT1 avec un ratio E/I préservé, les patients DT1 avec un ratio E/I abaissé ont une diminution de la tachycardie réflexe lors du redressement et une réduction du gain baroréflexe, un retard dans la correction de l'hypotension orthostatique, mais pas d'augm...