Vicente Alvarez

Prevalence, Persistence, and Clinical Significance of Masked Hypertension in Youth

Masked hypertension, an elevated daytime ambulatory blood pressure in the presence of a normal office blood pressure, confers an increased cardiovascular risk to adults. We investigated the prevalence, persistence, and clinical significance of masked hypertension in children and adolescents. We enrolled 592 youths (6 to 18 years old). Youths with masked hypertension (n=34) and a random sample of the normotensive participants (n=200) were followed-up. In a nested case-control study, we compared echocardiographic left ventricular mass among cases with persistent masked hypertension and normotensive controls. At baseline, mean age was 10.2 years; 535 youths were normotensive on office and daytime ambulatory blood pressure measurement (90.4%), and 45 had masked hypertension (7.6%). Compared with normotensive controls, participants with masked hypertension had a higher ambulatory pulse rate, were more obese, and were 2.5-times more likely to have a parental history of hypertension. Among 34 patients with masked hypertension (median follow-up 37 months), 18 became normotensive, 13 had persistent masked hypertension, and 3 had sustained hypertension. Patients with persistent masked hypertension (n=17) or who progressed from masked to sustained hypertension (n=3) had a higher left ventricular mass index (34.9 versus 29.6 g/m2.7; P=0.023) and a higher percentage with left ventricular mass index above the 95th percentile (30% versus 0%; P=0.014) than normotensive controls. In children and adolescents, masked hypertension is a precursor of sustained hypertension and left ventricular hypertrophy. This condition warrants follow-up and, once it becomes persistent, is an indication for blood pressure-lowering treatment.

The impact of obesity and body fat distribution on ambulatory blood pressure in children and adolescents.

To assess the relationship between obesity, body fat distribution, and blood pressure in children and adolescents, various measures of obesity and the waist-to-hip circumference ratio were related to casual and ambulatory blood pressure as measured using a SpaceLabs 90207 monitor during a regular school day. Seventy obese and 70 nonobese children aged 6 to 16 years were included in the study. Regardless of the time period analyzed (24 h, daytime, or nighttime), ambulatory blood pressure and casual blood pressure were significantly higher among the obese children. The differences in systolic blood pressure observed between the groups were attributable to the presence of obesity as estimated by the ponderal index and by skinfold thickness. Similarly, systolic and diastolic loads, as an assessment of high blood pressure values over 24 h, were significantly higher in the obese children when compared to the loads for the nonobese children. Waist-to-hip circumference ratio was independently associated, (in multiple regression analysis) with systolic blood pressure, whether during 24 h, daytime, or nighttime periods, after controlling for age, sex, current height, ponderal index, and tricipital skinfold thickness. This study demonstrates that obesity is a determinant of ambulatory and casual blood pressure. Since obese children with a predominantly abdominal fat mass show higher blood pressure values, evaluation of body fat distribution in children may help to identify subjects more susceptible to developing hypertension later in life.

Birth Weight Impacts on Wave Reflections in Children and Adolescents

Abstract—The objective of the present study was to assess central aortic pressure and wave reflection in children and adolescents at different birth weights. Two hundred nineteen healthy children (126 girls), from 7 to 18 years of age (mean, 11.3 years) and born at term after a normotensive pregnancy, were included. The subjects were divided according to birth weight: <2.5 kg, from 2.5 to 2.999 kg, from 3.0 to 3.5 kg, and >3.5 kg. Pressure waveforms were recorded from the radial artery of the wrist, and the waveform data were then processed by the SphygmoCor radial/aortic transform software module to produce the estimated aortic pressure waveform. Augmentation index, an estimate of the pulse wave reflection, was significantly higher in children with the lowest birth weights compared with the other birth weight groups. In a multiple regression analysis, short stature, low heart rate, female gender, and lower birth weight had independent significant inverse correlations to the augmentation index when adjusted for diastolic blood pressure (R2=0.21). In summary, the results showed a relatively aged phenotype of large-vessel function in the children with the lowest birth weights. These early alterations may be amplified throughout life and may contribute to the increased cardiovascular risk associated with low birth weight.

Birth Weight Influences Blood Pressure Values and Variability in Children and Adolescents

The objective of the present study was to assess the relationships between birth weight and the values and variability of ambulatory blood pressure. Six hundred thirty healthy children (369 girls) age 4 to 18 years (mean, 9.9 years) born at term after a normotensive pregnancy were included. The subjects were divided into 5 groups according to birth weight. For each subject, a 24-hour ambulatory blood pressure monitoring was performed according to the protocol designed. Average and variability (estimated as the standard deviation) of ambulatory blood pressure and heart rate were calculated separately for 24-hour, daytime, and nighttime periods. When values were adjusted for gender, current age, weight, and height, children with the lowest birth weights had the highest ambulatory blood pressure values and variability, whereas no differences in heart rate were observed. Multiple regression analysis showed that although current weight was the strongest predictor for 24-hour systolic blood pressure (P <0.001), there was also an independent and significant inverse relationship for birth weight (P <0.002) after controlling for gender, current age, and height. Likewise, birth weight was independently and inversely correlated with 24-hour systolic blood pressure variability (P <0.03). In conclusion, children who had lower birth weights tended to have not only the highest blood pressure values but also the highest blood pressure variability, independent of the increases in ambulatory blood pressure values. Knowing that high blood pressure variability is at least partially independent of blood pressure values, the importance of this variability on further blood pressure rises and/or on vascular damage later in life needs to be assessed in future studies.

Obesity, Body Fat Distribution, and Ambulatory Blood Pressure in Children and Adolescents

Obesity is a common disease with an ever‐increasing prevalence and usually with late‐onset consequences. If acquired during childhood, it tracks into adult life to some extent, and since the relationship between obesity and hypertension is well established in adults, obese children appear to be at particularly high risk of becoming hypertensive adults. In the authorsstudy, obese children seemed to have significantly higher casual and ambulatory blood pressure than nonobese children, except for nighttime diastolic blood pressure. The health effects of obesity may depend on the anatomic distribution of body fat, which in turn may be a better indicator of endocrinologic imbalance, environmental stress, or genetic factors than is fatness per se. Subjects with a higher waist‐to‐hip ratio or a larger waist, as an estimate of central obesity, tend to have higher blood pressure values even during childhood. Prevention of the onset of obesity in early life may be important to reducing the risk of coronary heart disease in later life.

Anomalías congénitas de las arterias coronarias del adulto descritas en 31 años de estudios coronariográficos en el Principado de Asturias: principales características angiográficas y clínicas

Objective. The aim of this study was to determine the incidence of adult congenital anomalies of the coronary arteries over 31 years of angiographic studies, describing their angiographic and clinical characteristics. The results have been compared with the main series published. Methods. The diagnostic angiographic reports done in the Principado de Asturias from 1968 to 1999 are reviewed. In those in which a congenital anomaly was diagnosed, the clinical report and the angiography were studied. The initial course of the anomaly was defined following angiographic criteria. Results. Thirteen thousand five hundred reports were reviewed describing 75 patients with 75 anomalies (0.5%) incluiding: anomalous origin of the left circumflex coronary artery (n = 24), coronary artery fistulae (n = 21), both coronary arteries arising from the left coronary sinus (n = 15), single coronary arteries (n = 6), both coronary arteries arising from the right coronary sinus (n = 2), separated origin of anterior descending and left circumflex coronary arteries (n = 3), anterior descending artery arising from the right coronary sinus (n = 2), and others (n = 1). Angiographic studies were done because of: angina (59%), dysnea (25%), atypical chest pain (7%), syncope (3%), dizziness (3%) and palpitations (3%). The initial course was retroaortic in all the circumflex arteries, interarterial in the right coronaries, anterior in the anterior descending arteries and retroaortic, septal and combined, in the left coronaries. Conclusions. Adult congenital anomalies of the coronary arteries are not very common and are usually casual findings of diagnostic angiographic studies. Left circumflex coronary artery anomalies are the most frequently diagnosed.

The spectrum of circadian blood pressure changes in type I diabetic patients

Background The objective of the present study was to characterize the spectrum of circadian blood pressure changes in type I diabetes at different stages of nephropathy by using two monitorings in each patient in order to avoid intra-individual variability. Patients and methods A total of 80 type I diabetic subjects and the same number of age, sex and awake mean blood pressure (BP)-matched controls were included. According to urinary albumin excretion, there were 57 normoalbuminurics, 15 persistent microalbuminurics and eight proteinurics. Two 24 h ambulatory blood pressure monitorings were performed at the same urinary albumin excretion stage in absence of antihypertensive treatment for each diabetic subject and for their respective control. Blood pressure and heart rate averages during 24 h, awake, sleep, and day : night ratio were calculated. Results Seven of the eight proteinuric subjects were hypertensives, whereas hypertension was absent in the normoalbuminuric and microalbuminuric groups. The intra-individual reproducibility in diabetics showed repeatability coefficients for the 24 h systolic and diastolic pressure of 33 and 42%, respectively. This reproducibility for the day : night ratio was generally worse, 57% for systolic and 59% for diastolic . A progressive increment in the mean ambulatory BP was observed across the three groups of diabetics and the differences in BP observed were most evident during the night-time period. Though no differences in the 24 h circadian pattern were present between the normoalbuminurics and their controls, nocturnal differences were observed, not only in microalbuminurics for systolic BP (P < 0.05), but also in proteinurics for both systolic BP (P < 0.01) as well as diastolic BP (P < 0.05). No differences were observed in heart rate among the diabetic groups. The non-dipping pattern in the two monitorings was observed in 80, 58, 18 and 10% of the proteinurics, microalbuminurics, normoalbuminurics and control groups , respectively. Conclusions Persistent abnormal circadian variability seems to be an early and frequent characteristic of type I diabetics with an increased urinary albumin excretion. Although present in some normalbuminuric subjects, the frequency of this abnormality increases as the incipient nephropathy progresses. By the time proteinuria is established, nearly all subjects present the abnormal pattern.

Relationship between Birth Weight and Awake Blood Pressure in Children and Adolescents in Absence of Intrauterine Growth Retardation

This study was designed to examine the relationship between birth weight (BW) and ambulatory blood pressure in children and adolescents, born at term in absence of intrauterine growth retardation. Twenty-four hour ambulatory blood pressure monitoring (ABPM) was performed on 332 children (150 boys), aged from 6 to 16 years. Subjects were stratified by BW tertiles and age. ABPM was performed using SpaceLabs 90207 monitor during a regular school day. Blood pressure (BP) was measured every 20 min from 06:00 to 24:00, and thereafter every 30 min. Means of systolic BP (SBP) and diastolic BP (DBP) during 24 h, daytime (08:00 to 22:00), and nighttime (24:00 to 06:00) were calculated. Systolic and diastolic load was estimated as the percentage of measurements above the age- and sex-specific 95th percentile during the 24 h. BW was inversely related to daytime (SBP (P = .04) and SBP load (P = .04) when controlled for sex, current height, ponderal index (weight/height3), and age. The predictive values of daytime SBP throughout the pediatric age group in the two extreme tertiles of BW (lowest, 2.500 to 3.200 kg; and highest, 3.501 to 4.820 kg) were obtained from regression equations including SBP during activity period or SBP load and age. Children who had lower BW tended to have higher daytime SBP or SBP load at any age although this difference was not statistically significant. These differences became more evident as the subjects got older. BW is a determinant of daytime SBP even in the absence of intrauterine growth retardation. The influence of BW seems to increase with age.

Delayed myocardial perforation following pacemaker implantation

Myocardial perforation is a rare complication following pacemaker implantation that may cause cardiac tamponade. If it does occur, it is usually at the time of lead insertion. This condition requires urgent recognition since the prompt drainage of the pericardial fluid may be lifesaving. We present a case report of myocardial perforation complicated by cardiac tamponade 4 days after pacemaker lead insertion that was repaired surgically.

Current and Birth Weights Exert Independent Influences on Nocturnal Pressure-Natriuresis Relationships in Normotensive Children

The objective was to study the impact of birth weight on the relationship between ambulatory blood pressure and urinary sodium excretion in children and adolescents. The study included 134 healthy children (61 boys), all Caucasians, who were born at term after a normotensive pregnancy. For each subject, a 24-hour ambulatory blood pressure monitoring and a complete urine collection were simultaneously performed according to the protocols designed. Average ambulatory blood pressure (BP) and the urinary excretion rates for sodium, potassium, and creatinine were calculated separately for 24-hour, awake, and sleep periods defined by a mini-diary. The excretion rate of sodium during sleep time was positively correlated with ambulatory systolic BP; such a positive relationship was not found for waking hours. Consequently, the impact of birth weight on the relationship between blood pressure and the urinary sodium excretion rate was analyzed during sleeping hours. Stepwise multiple regression analysis shows that although current weight was the strongest predictor for the sodium excretion rate during sleep (P<.001), there was also an independent significant direct relationship for birth weight (P<.04) after controlling for age, sex, and the average of systolic BP during sleep. Adjusted for current weight, a significant difference in the regression slopes relating urinary sodium excretion rate and systolic BP during sleep exists between children in the lowest (<3.100 kg) and the highest tertiles (>3.500 kg) of birth weight (P<.02). Differences in sodium excretion rates, adjusted for current weight, between the two extreme tertiles of birth weight became significant at the highest systolic BP (P<.04). The children who had the lowest birth weight tended to excrete less sodium during sleep. The results of the present study show a blunted pressure natriuresis curve in children and adolescents with the lowest birth weight. Whether this abnormal renal sodium handling may be present as an initial or as an intermediate mechanism leading to higher BP values must be assessed in additional studies.