Cold pressor test e dieta hipossódica

Association Between Blood Pressure Responses to the Cold Pressor Test and Dietary Sodium Intervention in a Chinese Population
Jing Chen, MD, MSc; Dongfeng Gu, MD, MSc; Cashell E. Jaquish, PhD; Chung-Shiuan Chen, MS; D. C. Rao, PhD; Depei Liu, PhD; James E. Hixson, PhD; L. Lee Hamm, MD; C. Charles Gu, PhD; Paul K. Whelton, MD, MSc; Jiang He, MD, PhD; for the GenSalt Collaborative Research Group
Arch Intern Med. 2008;168(16):1740-1746.
Background Blood pressure (BP) responses to the cold pressor test (CPT) and to dietary sodium intake might be related to the risk of hypertension. We examined the association between BP responses to the CPT and to dietary sodium and potassium interventions.
Methods The CPT and dietary intervention were conducted among 1906 study participants in rural China. The dietary intervention included three 7-day periods of low sodium intake (3 g/d of salt [sodium chloride] [51.3 mmol/d of sodium]), high sodium intake (18 g/d of salt [307.8 mmol/d of sodium]), and high sodium intake plus potassium chloride supplementation (60 mmol/d). A total of 9 BP measurements were obtained during the 3-day baseline observation and the last 3 days of each intervention using a random-zero sphygmomanometer.
Results Blood pressure response to the CPT was significantly associated with BP changes during the sodium and potassium interventions (all P < .001). Compared with the lowest quartile of BP response to the CPT (quartile 1), systolic BP changes (95% confidence intervals) for the quartiles 2, 3, and 4 were –2.02 (–2.87 to –1.16) mm Hg, –3.17 (–4.05 to –2.28) mm Hg, and –5.98 (–6.89 to –5.08) mm Hg, respectively, during the low-sodium intervention. Corresponding systolic BP changes during the high-sodium intervention were 0.40 (–0.36 to 1.16) mm Hg, 0.44 (–0.35 to 1.22) mm Hg, and 2.30 (1.50 to 3.10) mm Hg, respectively, and during the high-sodium plus potassium supplementation intervention were –0.26 (–0.99 to 0.46) mm Hg, –0.95 (–1.70 to –0.20) mm Hg, and –1.59 (–2.36 to –0.83) mm Hg, respectively.
Conclusions These results indicate that BP response to the CPT was associated with salt sensitivity and potassium sensitivity. Furthermore, a low-sodium or high-potassium diet might be more effective to lower BP among individuals with high responses to the CPT.

ITB e risco cardiovascular

Different Calculations of Ankle-Brachial Index and Their Impact on Cardiovascular Risk Prediction
Christine Espinola-Klein MD*, Hans J. Rupprecht MD, Christoph Bickel MD, Karl Lackner MD, Savvas Savvidis MD, Claudia M. Messow , Thomas Munzel MD, Stefan Blankenberg MD, for the AtheroGene Investigators
Background—An ankle-brachial index (ABI; ratio of ankle and brachial systolic blood pressure) <0.9 indicates peripheral arterial disease (PAD) and is a strong predictor of cardiovascular events. The aim of the present study was to address the prognostic value of different methods of ABI calculation.
Methods and Results—In 831 patients admitted with chest pain for diagnostic heart catheterization, blood pressure of both anterior and posterior tibial arteries was measured. ABI was calculated for each leg with the higher of the 2 ankle pressures (current definition of the American Heart Association) or with the lower of the 2 ankle pressures (modified definition) in relation to the higher of the left or right brachial systolic blood pressure. For each patient, the lower ABI from both legs was used for further evaluation. Fifteen patients (1.8%) with ABI >1.5 were excluded. We compared patients with ABI <0.9 according to the current definition (with PAD, n=204 [25.0%]), those with ABI 0.9 according to the modified definition (without PAD, n=524 [64.2%]), and those with ABI <0.9 according to the modified definition and 0.9 according to the current definition (suspected PAD, n=88 [10.8%]). Follow-up data (median 6.6 years) were available for 812 patients (99.5%); 157 patients (19.3%) experienced cardiovascular events (cardiovascular death, myocardial infarction, or stroke). Patients without PAD had the lowest cardiovascular event rate, whereas event rates were comparable for patients with PAD and those with suspected PAD (14.8% versus 28.4% versus 25.0%, respectively). In a fully adjusted Cox regression analysis that included patients without PAD as the reference group, the hazard ratio (95% CI) was 1.56 (0.97 to 2.53) for patients with suspected PAD and 1.67 (1.16 to 2.40) for patients with PAD.
Conclusions—When the higher ankle pressure is used for ABI calculation, a group of patients at high risk for cardiovascular events is overlooked. With a simple modification of ABI (use of the lower instead of the higher ankle pressure), more patients at risk could be identified.

Estresse, pressão arterial e peso ao nascer: diferenças por gênero

Sex-specific programming of cardiovascular physiology in children

Alexander Jones1,2,*, Alessandro Beda3, Clive Osmond1, Keith M. Godfrey1, David M. Simpson3 and David I. W. Phillips1 Eur Heart J 2008; DOI: 10.1093/eurheartj/ehn292.
Email: aj@mrc.soton.ac.uk
Aims: Increasing evidence suggests that adverse prenatal environments, as indicated by low birth weight, cause long-term changes in cardiovascular physiology that predispose to circulatory disease. The mechanisms are poorly understood, most human studies have been carried out in adults and little is known about early pathophysiological changes. Therefore, we have assessed the relationship between birth weight and cardiovascular physiology in children.
Methods and results: In 140 healthy boys and girls (aged 7–9 years), born at term and followed prospectively, we continuously recorded blood pressure, electrocardiograms and cardiac impedance before, during, and after 10 min of psychosocial stress (Trier Social Stress Test for Children). In boys, an association of lower birth weight with higher resting systemic arterial pressure (β = –6.8 mmHg/kg, P= 0.03) and a trend towards higher vascular resistance (β = –87 dyne s/cm5/kg, ns) were substantially strengthened following stress (β = –9.5 mmHg/kg, P= 0.003 and β = –139 dyne s/cm5/kg, P = 0.02, respectively). In girls, lower birth weight was associated with a shorter pre-ejection period (β = 8.0 ms/kg, P = 0.005) and corrected QT interval (β = 11.9 ms/kg, P = 0.003) at rest and little changed by stress.
Conclusion: Smaller size at birth is associated with sex-specific alterations in cardiac physiology; boys had higher systemic vascular resistance and girls had increased cardiac sympathetic activation.