Dagnovar Aristizábal

Hypertension types defined by clinic and ambulatory blood pressure in 14 143 patients referred to hypertension clinics worldwide. Data from the Artemis study

Objective: The Ambulatory blood pressure Registry TEleMonitoring of hypertension and cardiovascular rISk project was designed to set up an international registry including clinic blood pressure (CBP) and ambulatory blood pressure (ABP) measurements in patients attending hypertension clinics in all five continents, aiming to assess different daily life hypertension types. Methods: Cross-sectional ABP, CBP and demographic data, medical history and cardiovascular risk profile were provided from existing databases by hypertension clinics. Hypertension types were evaluated considering CBP (≥140/90 mmHg) and 24-h ABP (≥130/80 mmHg). Results: Overall, 14 143 patients from 27 countries across all five continents were analyzed (Europe 73%, Africa 3%, America 9%, Asia 14% and Australia 2%). Mean age was 57 ± 14 years, men 51%, treated for hypertension 46%, cardiovascular disease 14%, people with diabetes 14%, dyslipidemia 33% and smokers 19%. The prevalence of hypertension was higher by CBP than by ABP monitoring (72 vs. 60%, P < 0.0001). Sustained hypertension (elevated CBP and ABP) was detected in 49% of patients. White-coat hypertension (WCH, elevated CBP with normal ABP) was more common than masked hypertension (elevated ABP with normal CBP) (23 vs. 10%; P < 0.0001). Sustained hypertension was more common in Europe and America and in elderly, men, obese patients with cardiovascular comorbidities. WCH was less common in Australia, America and Africa, and more common in elderly, obese women. Masked hypertension was more common in Asia and in men with diabetes. Smoking was a determinant for sustained hypertension and masked hypertension. Conclusion: Our analysis showed an unbalanced distribution of WCH and masked hypertension patterns among different continents, suggesting an interplay of genetic and environmental factors, and likely also different healthcare administrative and practice patterns.

Insulin Resistance and Beat-to-Beat Cardiovascular Dynamics: A Constant Relationship Across Different Body Mass Index and Blood Pressure Categories

CONTEXT Epidemiological studies have shown a progressive increase in insulin resistance (IR) accompanying body weight gain and blood pressure (BP) increase. This has led to the consideration that hemodynamic effects of IR might depend on its relationship with body mass index (BMI) and BP. OBJECTIVE The aim of our study was to determine whether IR is associated with changes in hemodynamic indices of cardiovascular function across different categories of BMI (normal weight, overweight, and obese), and BP levels (normal, high normal, and hypertension). DESIGN, SETTING AND PARTICIPANTS This was a cross-sectional study conducted in a population sample of nondiabetic individuals (n = 731). MEASURES Insulin resistance was evaluated with the homeostasis model assessment of insulin resistance (HOMA) and subjects were classified into quartiles according to HOMA index values. Synchronized beat-to-beat recordings of stroke volume (impedance cardiography) and R-R interval, along with repeated auscultatory BP measurements were performed. Derived hemodynamic parameters were computed and averaged. RESULTS Analysis of covariance adjusting for confounders showed significant differences for most hemodynamic parameters among different quartiles of HOMA index both in the general population and within each BMI and BP category. Overall, increasing values of HOMA index were associated with significantly higher BP; and reduced R-R interval, stroke index, cardiac index, pre-ejection period and left ventricular ejection time (P < .01) across different categories of BMI and BP. CONCLUSIONS These findings suggest that even small increases in HOMA index (not necessarily in the range to define IR) may induce significant changes on indices of cardiovascular function even in normal-weight and normotensive subjects, emphasizing the importance of IR at an early stage of the cardiovascular risk continuum.

Web Laboratory Experiences for Elearning: The Michelson Interferometer

This paper describes the design and the implementation of software-hardware solution that allow Web laboratory experiences with the Michelson Interferometer. The hardware has a TINI (Tiny InterNet Interfaces), a control system given by a PIC microcontroller and a IP camera. The software was implemented with JAVA and the operating system was LINUX. It’s possible with this system to teach the principles and functionalities of the Michelson Interferometer via Web. The idea is that students of remote places can be use laboratory equipment using the Web.

[PP.LB03.06] LOOKING FOR MISSING HYPERTENSION FOOTPRINTS IN THE CARDIOVASCULAR RISK LOCUS 9P21.3: A TALE OF 7 SNPS

Objective: A region within 9p21.3 has been consistently associated with risk of coronary heart disease, cardiovascular disease or atherosclerosis. Neighboring regions have associations with other chronic diseases including type 2 diabetes. Surprisingly, the 9p21.3 cardiovascular risk region has been repeatedly reported to lack association with conventional risk factors such as hypertension/blood pressure or hyperlipidemia/plasma lipoproteins, leading some authors to suggest that the locus might affect cardiovascular risk via a novel, still unknown alternative route (Holdt & Teupser 2012, 2013, McPherson 2013). We revisited the ‘missing hypertension’ enigma in the light of data from the population of Medellín, Colombia, which has mixed ancestral origins and has been characterized within the 1000 Genomes Project. Design and method: For a cohort of individuals in Medellín (n > 350) from whom we had obtained clinical and physiological data, we genotyped 65 SNPs from 9p21.3. Results: In the raw (uncorrected) associations of our selected 9p21.3 SNPs with physiological variables, the strongest were largely for variables or criteria representing blood pressure or hypertension. We found an island (∼ 21 kb) within the cardiovascular risk region containing seven genotyped SNPs that showed associations with mean blood pressure, and a modest but monotonic increase in this variable from homozygous minor-allele genotypes through heterozygous to major-allele homozygous. The increase corresponded to the rise in cardiovascular risk found for those 7 SNPs in other population studies, and was stronger in men. Homozygous individuals plotted versus age showed an upward shifted regression line for the major allele. Mixed ancestry (estimated via 30 AIMs) did not trivially explain the effect, despite strong variability in the alleles’ frequencies among continents. The 7 SNPs are located upstream of the CDKN2A gene, possibly in regulatory DNA. Conclusions: We could not confirm a reported lack of association between the 9p21.3 risk locus and blood pressure/hypertension in our cohort. Consistent footprints of hypertension in a population could suggest hypertension-related etiologies of cardiovascular risk rather than a novel route. Differences from other studies’ results might reflect different ways of obtaining mean blood pressure values, a chance observation, and/or differences among populations.

ASSOCIATION OF ARG16GLY POLYMORPHISM OF THE BETA-2 ADRENERGIC RECEPTOR (B2AR) GENE WITH BAROREFLEX SENSITIVITY AND INDICES OF AUTONOMIC CARDIOVASCULAR MODULATION: PP.32.258

Objective: Sympathetic nervous system plays a key role in blood pressure control and functional polymorphisms of the beta-2 adrenergic receptor (B2AR) have been implicated in the pathogenesis of hypertension. In particular, functional polymorphism Arg16Gly (46A–>G rs1042713), has been proved to be of clinical relevance. However, limited information is available on its association with baroreflex sensitivity (BRS) and other parameters of autonomic cardiovascular regulation. Aim of our study was to explore this issue. Methods: In the frame of Medellins Heart Study, a probabilistic sample of 800 subjects from the general population of Medellin (Colombia) was recruited. Individuals with a diastolic blood pressure (DBP)>70th percentile of distribution curve (DBP>85 mmHg), aged 30-65 years and not receiving antihypertensive therapy, were selected (n = 92). Arg16Gly polymorphism was forward and backward genotyped (accuracy >99%), using automated DNA sequencer 3730XL (ABI-Prism). Cardiovascular autonomic modulation was assessed by computer analysis of 10 min beat-to-beat BP and ECG recordings obtained in supine position (Task Force Monitor). BRS was estimated by sequence method as the slope of spontaneous concomitant increases or decreases in systolic (S)BP and RR interval. Low-frequency (LF) and high-frequency (HF) spectral components of heart rate variability (HRV) were assessed by Fourier analysis and expressed in normalized units (nu). LF/HF ratio was also calculated. Results: Allelic distribution of Arg16Gly polymorphism was in Hardy-Weinberg equilibrium. There was highly significant variation in all parameters between Arg/Arg, Arg/Gly and Gly/Gly genotypes. After adjustment for age, sex, smoking, diabetes, SBP and BMI, subjects with Arg/Arg genotype exhibited significantly lower BRS (p < 0.007), higher HRV sympathetic indices (LF; p < 0.003 and LF/HF; p < 0.002) and lower HRV parasympathetic indices (HF; p < 0.003) than those with Gly/Gly genotype. See table. Conclusions: These results indicate that ADRB2 gene may be involved in the modulation of cardiac baroreflex and HRV in humans. In particular, Arginine homozygous genotype of Arg16Gly polymorphism was associated with a decreased BRS and higher indirect indices of sympathetic activity in subjects with high blood pressure. Figure 1. No caption available.

ASSOCIATION OF ARG16GLY POLYMORPHISM OF THE BETA-2 ADRENERGIC RECEPTOR (B2AR) GENE WITH SYSTOLIC HYPERTENSION IN A LATIN-AMERICAN POPULATION FROM COLOMBIA: PP.21.319

Objective: Beta-2 adrenergic receptor (B2AR) gene is among the candidate genes most widely studied in hypertension. In particular, Arg16Gly (46 A–>G rs1042713) a non-synonymous coding polymorphism of the B2AR, has been reported to be associated with hypertension with inconclusive results. The aim of the present study was to test the association between this polymorphism and essential hypertension in a Latin American population. Methods: A total of 800 individuals aged 30–65 years were recruited for the study. They constituted a random and representative sample of the general population of the city of Medellin (Colombia). Arg16Gly polymorphism was repeatedly genotyped (forward and backward, genotype accuracy >99%), using automated DNA sequencer 3730XL (ABI Prism). Blood pressure (BP) levels were defined by the average of four conventional sitting BP measurements (2007 ESH-ESC Guidelines) made at five min intervals by two trained physicians. All measurements were performed in the left arm at the heart level after 5 min rest using a standard mercury sphygmomanometer. Systolic hypertension was defined as a systolic (S)BP at or above 140 mmHg. Results: Allelic distribution of the Arg16Gly polymorphism was in Hardy-Weinberg equilibrium. In the logistic regression analysis, systolic hypertension was considered as the dependent variable and only individuals not under antihypertensive treatment were included (n = 599). After adjustment for age, sex, diabetes, BMI and smoking (independent variables), individuals homozygous for Gly16 (Gly/Gly genotype) had a higher significant risk of systolic hypertension (89% increase in odds of having systolic hypertension) when compared to the individuals with other genotypes (Arg/Arg or Arg/Gly) [odds ratio (OR) = 1.89; 95% confidence interval (CI) = 1.18–3.03; p = 0.008]. See table Conclusions: These results support the hypothesis that polymorphisms in the ADRB2 gene are involved in the modulation of blood pressure levels in humans. In particular, the presence of a Glycine homozygous genotype of the Arg16Gly polymorphism is associated with an increased risk of systolic hypertension in subjects of Latin-American origin. Figure 1. No caption available.