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Cardiovascular Reactivity and Factors of
Cardiovascular Risk in Normotensive
People Younger than 40

Benet, Mikhail; Apollinaire, Juan José; Torres, Joel.

Faculty of Medical Sciences of Cienguegos, Cuba

RESUMEN

SUMMARY
Background: It has been observed that the cardiovascular hiperreactivity (CHR) it is associated to cardiovascular risk factors (CRF) in the population. Also, many authors look for in the CHR an important element for the prediction of the high blood pressure (HBP).
Objective: The main of this study is to know if these factors are also associated in the population of individuals with less than 40, it could be important to modify lifestyles and to intervene in the prevention of cardiovascular illnesses.
Methods: It was carried out a correlate descriptive study with a sample of 249 normotensive people of both sexes between 18 and 40 years of age. There were formed two groups starting from the results of the sustained weight test (SWT), based on the application of an isometric exercise to produce cardiovascular reactivity. One of the groups formed by the cardiovascular hyperreactive ones (n=62), with values of arterial pressure (AP) ³ 90/140 mmHg after the SWT, and the other one, formed by the cardiovascular normorreactive ones (n=187), with values of AP <90/140 mmHg. By means of a model of logistical regression the association was determined among age, sex, family history of arterial hypertension (FH of AHT), physical activity (PhAc), consumption of cigarettes (CC), ingestion of alcoholic drinks (IAD), consumption of salt (CS), Boby mass index (BMI) and race with the state of cardiovascular hyperreactivity.
Results: The risk of people with FH of AHT of having cardiovascular hyperreactivity, was twice bigger (OR=2,88 TI 95%: 1,54-5,36). For every year of age, the hyperreactivity risk increased in 1,08 times and it arrived up to 1,14 times. On the other hand, the BMI showed a significant relation independent from the state of vascular hyperreactivity (OR=1,11 TI 95%: 1,01-1,21). The rest of the studied variables didn't show association with the state of cardiovascular hyperreactivity
Conclusions: The normotensive people between 18 and 40 years of age, have a bigger risk of cardiovascular reactivity if they have FH of AHT, if their BMI increases or with the rise of age.

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INTRODUCTION
   The cardiovascular reactivity (CVR) is defined as the changes in blood pressure, heart frequency or other hemodynamic parameters in answer to a physical or mental stimulus.

   It has been able to observe that the hypertensive people present a bigger CVR than the normotensive ones, a bigger CVR has also been found in young people presenting factors of cardiovascular risk (FCVR). On the other hand, CVR as answer to stress, has been proposed as a factor of risk (FR) of arterial hypertension (AHT), being evidenced an increase of the blood pressure, as well as of the total peripheral resistance (TPR), in children with family history of coronary artery illnesses with regard to other children subjected to a physical stress. Nevertheless, its importance to predict the future of the high blood pressure (HBP) and of the cardiovascular illnesses (CVI) is in discussion.

OBJECTIVE
   To know if the cardiovascular reactivity and the factors of cardiovascular risk are also associated in the population of individuals with less than 40 years. It could be important to modify lifestyles and to intervene in the prevention of cardiovascular illnesses.

MATERIAL AND METHOD
   It was carried out a correlate descriptive study in which there were formed two groups starting from the universe of the 249 normotensive people, of both sexes, between 18 and 40 years of age. All the studied people belonged to the clinic 17 of the municipality of Cienfuegos, Cuba. Cardiovascular hyperreactive people (CHP) formed the first group. The second group integrated by cardiovascular normo-rreactive people (CNRP). To determine the normotensive people, it was used the approach of the North American Committee of Prevention, Detection, Evaluation and Treatment of High Blood Pressure. Hypertensive individuals, with myocardialischemia and pregnant women were excluded.

   For the determination of normorreactive people and hyperreactive vascular people, the Sustained Weight Test was applied" (SWT). People that had levels of pressure below 90 percentile of the distributions of the systolic pressure (SP) and/or diastolic pressure (DP), after the SWT, were classified as normorreactive and those with the same values or superior to this level, constituted the hyperreactive group.

   The SWT, is a variant of the tests that use the isometric exercise to induce hemodynamic modifications of the cardiovascular system. It was carried out by maintaining a weight of 500 grams in the left hand with the arm extended in right angle to the body for 2 minutes. The arterial pressure was taken in the opposite arm before the exercise and in the last 20 seconds of the last minute.

   The factors of risk studied were: age, sex, family history of hypertension (FHH), physical activity (PhAc), consumption of cigarettes (CC), ingestion of alcoholic drinks (IAD), body mass index (BMI), consumption of salt (SC) and race. The statistical analysis of the data was carried out with the program SPSS 9. Data are presented by means of numbers and percentages in tables and graphics; a model of logistical regression was built to reject the null and void hypothesis of non-association among factors of cardiovascular risk with the state of cardiovascular reactivity. The independent variables or variables of prediction of this model were: age, BMI, sex, FHH PhAc, CS, IAD, CC and race. The dependent variable in this model was either: cardiovascular answer, a dichotomic variable that had as possible answers: cardiovascular hyperreactivity or, cardiovascular normorreactivity. The parameters of the pattern were considered for the method of maximum verisimilitude. It was put as level of significance of inclusion of the variables of prediction p <=0,05 and of exclusion p>=0,10.It was also carried out the calculation of the odds ratio (OR), and the trust interval of 95% (TI 95%) for each one of the variables of prediction that entered in the pattern.

RESULTS
   The values of the 90 percentile of the distributions of pressures were of 140 mmHg for the SP, and of 90 mmHg for the DP. Of the total of the sample, 187 people were classified as vascular normorreactive, and 62 as hyperreactive, Figure 1.

   Of the 249 studied people, 111 (44,5%) were of male sex and 138 (55,4%) of female sex, age average was of 27,8 SD ± 6,24 years for the normorreactive ones and of 31,3 ± 6,17 years for the hyperreactive ones, and the BMI of 23,14 SD ± 3,03 for the first ones and of 24,71 SD ± 3,78 for the second ones. The other studied variables are presented in the Table 1.

   The risk that a person with family history of arterial hypertension has vascular hyperreactivity, was of more than twice with regard to those who didn't have these records (OR=2,88 TI 95%: 1,54-5,36). It was also significant the relation between age and the risk of having a cardiovascular hyperreactivity; for every year of age the hyperreactivity risk increased in 1,08 times and it reached to 1,14 times. Besides these two variables, the BMI, also showed an independent significant relation with the state of vascular hyperreactivity in normotensive people (OR=1,11 TI 95%: 1,01-1,21). The rest of the studied variables didn't show association with the state of cardiovascular hyperreactivity, Table 2. Besides, the body mass index was bigger in the cardiovascular hyperreactive people who smoked from 1 to 9 cigarettes, but it diminished as consumption of cigarettes increased in these people, Figure 2.

 

DISCUSSION
   The criteria to consider a person as cardiovascular hyperreactive (CVHR) are very varied and not only for the numerous tests that are used to get to them, but also for the levels of pressure that have been used by other authors. The 90 percentile criterion, sets values of pressure in 90 mmHg for the diastolic one and 140 mmHg for the systolic one. This criterion increases the rank where it is considered an individual as CVHR, when he is in state of rest and has levels of normal pressure. And it could contribute in a significant way to the prevention of the high blood pressure and of the cardiovascular illnesses.

   The main result of our work is that it demonstrates the high risk that people with family history of hypertension have of suffering a state of cardiovascular hyperreacivity to the isometric exercise. It is well known that the condition that an individual has family history of hypertension, has more risk of suffering this entity. Lemne C E, found in children with family history of hypertension, levels of blood pressure before stress, significantly superior to the rest of the children. Besides, there have been found bigger values of arterial pressure in children and in adolescents with family history of hypertension, than in people without this record.

    It has also been observed that people with exaggerated cardiovascular answer to the physical exercise have an independent risk of having arterial hypertension. Therefore, the fact that this study shows that normotensive young people with family history of hypertension have, independently of other factors of risk, a risk of more than twice of having a vascular reactivity increased to the isometric exercise, is important. This can help so much to patients as well as to doctors, on those individuals with more risk of suffering hypertension, and in that way, to be able to incorporate healthy lifestyles that allow to diminish the risk of hypertension for other factors that contribute to the appearance of this entity.

   Some authors outline that the relationship between consumption of cigarettes (CC) and high blood pressure (HBP), seems to be given by an accentuation of the activity of the sympathic nervous system that causes an increase of the systolic volume, heart rate, miocardic-contractility and total peripheral resistance. Girdler SS and others, have found a bigger cardiovascular answer in smoking women with regard to the smoking men. In this work, a significant association was not demonstrated between the SH and the included CVHR, although it was not significant from the statistical point of view, a decrease of the hyperreactive risk was seen as the consumption of cigarettes was bigger.

   It is probable that these results are so because the BMI diminished in the hyperreactive people as they consumed a bigger number of daily cigarettes. In other works it has been observed that people who stop smoking have higher values of pressure than normotensive people and habitual smokers, and that the risk of HBP is increased apparently in people that stop smoking, by the increase of the BMI.

   Contrary to the previous situation, a significant relation was observed between the BMI and the risk of cardiovascular hyperreactivity, what confirms once more the risk that obese people have of suffering from arterial hypertension and cardiovascular illnesses. Also, this discovery supports the results that demonstrate that people who stop smoking, and don't develop actions that prevent them from getting fatter, have a bigger risk of developing arterial hypertension.

   The age was related with the risk of cardiovascular hyperreactivity. It is known the association between age and arterial hypertension, many works have demonstrated that arterial pressure increases with the age and that this is a factor of independent risk for the cardiovascular illnesses.

   The other evaluated variables didn't associate significantly to the cardiovascular hyperreactivity. Nevertheless, it is important to point out the progressive increment of the risk of hyperreactivity with the increase of the consumption of alcohol. We don't find works in the literature that relate sedentarism, consumption of salt and consumption of alcohol with the state of CVHR. This doesn't mean that they do not exist. However, an association in fact has been seen between these variables and the HBP. In the community of study for the arteriosclerosis risk (ARIC), Pereira, found a smaller risk of hypertension in medium age people that carry out physical activity regarding the sedentary ones.

CONCLUSIONS
   We can say that the risk of cardiovascular hyperreactivity, in young normotensive people is significantly associated with the family history of hypertension, the increment of age and the increase of the BMI. The body mass index diminishes in hyperreactive people as they have a bigger consumption of daily cigarettes, what could explain the decrease of the hyperreactivity risk in these people. Sex, consumption of salt, consumption of alcohol and race didn't associate in a significant way with the state of HRCV in these individuals.

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Reactividad Cardiovascular y Factores de Riesgos Cardiovasculares en Individuos
Normotensos Menores de 40 Años.

RESUMEN
Introducción: Se ha observado que la hiperreactividad cardiovascular (HRCV) está asociada a factores de riesgo cardiovasculares en la población general (FRCV). Además, muchos autores buscan en la HRCV un elemento importante para la predicción de la hipertensión arterial.
Objetivo: El principal objetivo de este estudio es conocer si la HRCV se asocia a los FRCV en la población de individuos menores de 40 años.
Métodos: Se realizó un estudio descriptivo correlacionar con una muestra de 249 individuos normotensos de ambos sexos entre 18 y 40 años de edad. Se formaron dos grupos a partir de los resultados de la prueba del peso sostenido (PPS), basada en la aplicación de un ejercicio isométrico para producir reactividad cardiovascular. Uno de los grupos formado por hiperreactivos cardiovasculares (n=62), con valores de presión arterial (TA) ? 90/140 mmHg después de la PPS, y el otro, formado por normorreactivos cardiovasculares (n=187), con valores de TA < 90/140 mmHg. Mediante un modelo de regresión logística se determinó la asociación entre la edad, sexo, historia familiar de hipertensión arterial (HF de HTA), actividad física (AcF), consumo de cigarros (CC), ingestión de bebidas alcohólicas (IBA), consumo de sal (CS) y la raza con el estado de hiperreactividad cardiovascular.
Resultados: El riesgo de los individuos con HF de HTA de tener hiperreactivad cardiovascular, fue 2 veces mayor (OR=2,88 IC 95%: 1,54-5,36). Por cada año de edad el riesgo de hiperreactividad aumentó en 1,08 veces y llegó hasta 1,14 veces. Por otro lado, el IMC mostró una relación significativa independiente con el estado de hiperreactividad vascular (OR=1,11 IC 95%: 1,01-1,21). El resto de las variables estudiadas no mostraron asociación con el estado de hiperreactividad cardiovascular.
Conclusiones: Los individuos normotensos entre 18 y 40 años de edad tienen un mayor riesgo de reactividad cardiovascular si tienen HF de HTA, si su IMC aumenta, o con el aumento de la edad.

 

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2nd Virtual Congress of Cardiology

Dr. Florencio Garófalo
Steering Committee
President
Dr. Raúl Bretal
Scientific Committee
President
Dr. Armando Pacher
Technical Committee - CETIFAC
President
fgaro@fac.org.ar
fgaro@satlink.com
rbretal@fac.org.ar
rbretal@netverk.com.ar
apacher@fac.org.ar
apacher@satlink.com

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