Vascular dynamics in isolated systolic arterial hypertension

Overweight, Obesity, and Age Are the Main Determinants of Cardiovascular Risk Aggregation in the Current Mexican Population: The FRIMEX III Study

Background: The Mexican population exhibits several cardiovascular risk factors (CVRF) including high blood pressure (HBP), dysglycemia, dyslipidemia, overweight, and obesity. This study is an extensive observation of the most important CVFRs in six of the most populated cities in Mexico. Methods: In a cohort of 297,370 participants (54% female, mean age 43 ± 12.6 years), anthropometric (body mass index (BMI)), metabolic (glycemia and total cholesterol (TC)), and blood pressure (BP) data were obtained. Results: From age 40, 40% and 30% of the cohort's participants were overweight or obese, respectively. HBP was found in 27% of participants. However, only 8% of all hypertensive patients were controlled. Fifty percent of the subjects 50 years and older were hypercholesterolemic. Glycemia had a constant linear relation with age. BMI had a linear correlation with SBP, glycemia, and TC, with elevated coefficients in all cases and genders. The β1 coefficient for BMI was more significant in all equations than the other β, indicating that it greatly influences the other CVRFs. Conclusions: TC, glycemia, and SBP, the most critical atherogenic factors, are directly related to BMI.

Arterial stiffness and hypertension in a large population of untreated individuals: the Rotterdam Study

OBJECTIVE

We studied whether arterial stiffness measured as aortic pulse wave velocity (aPWV) and carotid distensibility was associated with different subtypes of hypertension in a large population of untreated middle-aged and elderly men and women.

METHODS

The study was conducted within the framework of the population-based Rotterdam Study. We included 4088 individuals with information on aPWV, with 3554 individuals with carotid distensibility measurements without use of antihypertensive medication. Isolated systolic hypertension (ISH) was defined as SBP at least 140 mmHg and DBP less than 90 mmHg. Combined systolic and diastolic hypertension (Sys/Dia hypertension) was defined as SBP at least 140 mmHg and DBP at least 90 mmHg. Analysis of covariance was used to compare means of arterial stiffness for the different subtypes of hypertension. Multinomial logistic regression analysis was performed to investigate the association of arterial stiffness and the subtypes of hypertension in models adjusted for age, sex, mean arterial pressure, heart rate and cardiovascular risk factors.

RESULTS

The mean age of the individuals was 68 years: 45.3% were men, 1597 individuals had ISH and 441 individuals had Sys/Dia hypertension. aPWV was higher (13.2 vs. 12.9 m/s; P = 0.008) in individuals with ISH compared to those with Sys/Dia hypertension. Multivariate odds ratios and corresponding 95% confidence interval of aPWV for ISH were 1.53 (1.38-1.71) and 1.28 (1.09-1.53) for Sys/Dia hypertension. Corresponding odds ratios associated with carotid distensibility were 0.84 (0.75-0.94) and 0.66 (0.54-0.81), respectively. Age significantly modified the association of aPWV with subtypes of hypertension (P < 0.001).

CONCLUSION

In a large untreated population, we found significant associations of both aPWV and carotid distensibility with ISH and Sys/Dia hypertension. individuals with ISH had higher values of aortic stiffness when compared to individuals with Sys/Dia hypertension, a difference that was most pronounced at older age. The results suggest that aortic stiffness contributes to ISH in older individuals without treatment for hypertension.

Is Peri-Operative Isolated Systolic Hypertension (ISH) a Cardiac Risk Factor?

We are presenting a review of Isolated Systolic Hypertension (ISH) as a cardiovascular risk factor with emphasis on the perioperative period.

Isolated systolic hypertension is associated with aging and is the most frequent subtype (65%) among patients with uncontrolled hypertension. ISH is strongly associated with increased risks of cardiac and cerebrovascular events exceeding those in comparably aged individuals with diastolic hypertension. Patients with ISH show an increase in left ventricular (LV) mass and an increase in the prevalence of left ventricular hypertrophy (LVH). These LV changes increase cardiovascular events and frequently lead to diastolic dysfunction (DD). Treatment to reduce elevated systolic blood pressure has been shown to reduce the risk of cardiovascular events.

In the perioperative setting, essential hypertension has not been found to be a significant risk factor for cardiac complications. Most of the studies were based on the definition of essential hypertension and underpowered in sample size. The significance of perioperative ISH, however, is not well studied, partly due to its recognition only fairly recently as a cardiovascular risk factor in the non-surgical setting, and partly due to the evolving definition of ISH.

Perioperative cardiac complications remain a significant problem to the healthcare system and to the patient. Although the incidence of perioperative cardiac complications is prominent in high-risk patients as defined by the Revised Cardiac Risk Index (RCRI), the bulk of the cardiac complications actually occur in low-risk group. Currently, little understanding exists on the occurrence of perioperative cardiac complications in low- risk patients. A factor such as ISH, with its known pathophysiological changes, is a potential perioperative risk factor.

We believe ISH is an under-recognized perioperative risk factor and deserves further studying. Our research group has recently been funded by the Heart Stroke Foundation (HSF) to examine ISH as a perioperative risk factor (PROMISE Study).

Metformin, arterial function, intima-media thickness and nitroxidation in metabolic syndrome: the mefisto study

1. Metabolic syndrome (MS) is one of the greatest public health problems in Mexico, where more than 75% of adults in urban populations are overweight or obese. Metabolic syndrome has several comorbidities, which result in a high cardiometabolic risk. 2. Some of the vasopathogenic phenomena in MS are caused by nitroxidant stress, secondary to cardiometabolic dysfunction. 3. The action of metformin to diminish or control MS remains a matter of debate. 4. In the present study, 60 patients with at least three diagnostic criteria for MS were divided into two groups. Both groups received similar dietary counselling, but one group was given 850 mg metformin daily. 5. The variables assessed were body mass index, waist circumference, systolic and diastolic blood pressures (SBP and DBP, respectively), total cholesterol (TC), high- and low-density lipoprotein-cholesterol, triglycerides (TG), fasting glucose, nitroxidant metabolites (free carbonyls, malondialdehyde, dityrosines and advanced oxidative protein products (AOPP)), nitric oxide (NO), carotid vascular stiffness, carotid intima-media thickness (IMT) and C-reactive protein (CRP). 6. After 1 year follow up, both groups reported weight loss, as well as decreases in waist circumference, SBP and DBP. 7. Patients on metformin exhibited reductions in TC and IMT and there were marked changes in nitroxidation: levels of carbonyls, dityrosines and AOPP were reduced, whereas those of NO were increased, indicating better endothelial function. In addition, in patients given metformin, CRP levels decreased. 8. In conclusion, metformin has a considerable beneficial effect on nitroxidation, endothelial function and IMT in patients with MS.

Age, hypertension and arterial function

1. Ageing exerts a marked effect on the cardiovascular system and, in particular, the large arteries. Using a variety of techniques to assess arterial stiffness, many cross-sectional studies have demonstrated a significant relationship between age and aortic stiffness, although the age-related changes observed in peripheral arteries appear to be less marked. 2. The relationship between arterial stiffness and hypertension is more complex. The distending, or mean arterial, pressure is an important confounder of measurements of arterial stiffness and, therefore, must be taken into consideration when assessing arterial stiffness in hypertensive subjects or investigating the effect of antihypertensive agents. Current methods for correcting for differences in distending pressure involve pharmacological manipulation, statistical correction or mathematical manipulation of stiffness indices. 3. Many studies have provided evidence that both peripheral (muscular) and central (elastic) arteries are stiffer in subjects with mixed (systolic/diastolic) hypertension compared with normotensive subjects. However, it is unclear to what extent differences in mean arterial pressure explain the observed differences in hypertensive subjects. In contrast, isolated systolic hypertension is associated with increased aortic, but not peripheral artery, stiffness, although the underlying mechanisms are somewhat unclear. 4. Traditional antihypertensive agents appear to reduce arterial stiffness, but mostly via an indirect effect of lowering mean pressure. Therefore, therapies that target the large arteries to reduce stiffness directly are urgently required. Agents such as nitric oxide donors and phosphodiesterase inhibitors may be useful in reducing stiffness via functional mechanisms. In addition, inhibitors or breakers of advanced glycation end-product cross-links between proteins, such as collagen and elastin, hold substantial promise.

Matrix Metalloproteinase-9 (MMP-9), MMP-2, and Serum Elastase Activity Are Associated With Systolic Hypertension and Arterial Stiffness

Background— Arterial stiffness is an independent determinant of cardiovascular risk, and arterial stiffening is the predominant abnormality in systolic hypertension. Elastin is the main elastic component of the arterial wall and can be degraded by a number of enzymes, including matrix metalloproteinase-9 (MMP-9) and MMP-2. We hypothesized that elastase activity would be related to arterial stiffness and tested this using isolated systolic hypertension (ISH) as a model of stiffening and separately in a large cohort of healthy individuals.

Methods and Results— A total of 116 subjects with ISH and 114 matched controls, as well as 447 individuals free from cardiovascular disease were studied. Aortic and brachial pulse wave velocity (PWV) and augmentation index were determined. Blood pressure, lipids, C-reactive protein, MMP-9, MMP-2, serum elastase activity (SEA), and tissue-specific inhibitor 2 of metalloproteinases were measured. Aortic and brachial PWV, MMP-9, MMP-2, and SEA levels were increased in ISH subjects compared with controls ( P =0.001). MMP-9 levels correlated linearly and significantly with aortic ( r =0.45; P =0.001) and brachial PWV ( r =0.22; P =0.002), even after adjustments for confounding variables. In the younger, healthy subjects, MMP-9 and SEA were also independently associated with aortic PWV.

Conclusions— Aortic stiffness is related to MMP-9 levels and SEA, not only in ISH, but also in younger, apparently healthy individuals. This suggests that elastases including MMP-9 may be involved in the process of arterial stiffening and development of ISH.

Glycation end-product cross-link breaker reduces collagen and improves cardiac function in aging diabetic heart

Aging and diabetes mellitus (DM) both affect the structure and function of the myocardium, resulting in increased collagen in the heart and reduced cardiac function. As part of this process, hyperglycemia is a stimulus for the production of advanced glycation end products (AGEs), which covalently modify proteins and impair cell function. The goals of this study were first to examine the combined effects of aging and DM on hemodynamics and collagen types in the myocardium in 12 dogs, 9-12 yr old, and second to examine the effects of the AGE cross-link breaker phenyl-4,5-dimethylthazolium chloride (ALT-711) on myocardial collagen protein content, aortic stiffness, and left ventricular (LV) function in the aged diabetic heart. The alloxan model of DM was utilized to study the effects of DM on the aging heart. DM induced in the aging heart decreased LV systolic function (LV ejection fraction fell by 25%), increased aortic stiffness, and increased collagen type I and type III protein content. ALT-711 restored LV ejection fraction, reduced aortic stiffness and LV mass with no reduction in blood glucose level (199 +/- 17 mg/dl), and reversed the upregulation of collagen type I and type III. Myocardial LV collagen solubility (%) increased significantly after treatment with ALT-711. These data suggest that an AGE cross-link breaker may have a therapeutic role in aged patients with DM.

Reversal of pathophysiologic changes with long-term lisinopril treatment in isolated systolic hypertension

The purpose of this study was to evaluate in a prospective, double-blind, placebo-controlled study the effect of long-term (2-year) lisinopril treatment on cardiovascular end-organ damage in patients with previously untreated isolated systolic hypertension (ISH). All patients with ISH were derived from a population screening program. End-organ damage measurements, done initially and after 6 and 24 months of treatment, included measurements of aortic distensibility and echocardiographic left ventricular mass index (LVMI) and diastolic function. Blood pressure was measured by office and ambulatory measurements. Of the 97 subjects with ISH selected from the screening, 62 (30 lisinopril) completed the study according to protocol. Office blood pressure decreased in both groups, but ambulatory results significantly decreased with lisinopril-treatment only. Aortic distensibility increased significantly with lisinopril, as opposed to a decrease in placebo-treated subjects. The main effect of increased distensibility occurred between 6 and 24 months, whereas ambulatory blood pressure changed mainly in the first 6 months of treatment. LVMI decreased in both treatment groups, with a significantly higher reduction in lisinopril-treated subjects. Left ventricular diastolic function showed no significant changes in either group. The vascular pathophysiologic alterations of ISH-a decreased aortic distensibility-can be improved with long-term lisinopril treatment, whereas values deteriorate further in placebo-treated subjects. These results, in one of the first studies including subjects with previously untreated ISH only, indicate that lisinopril treatment might favorably influence the cardiovascular risk of ISH.