The influence of circadian blood pressure changes on aortic distensibility and left ventricular diastolic function in hypertensive individuals

Blood Pressure Rhythm and Blood Pressure Variability as Risk Factors for White Matter Lesions: A Cross-Sectional Study

Background

White matter lesions are common in the elderly. The aim of this study was to explore the correlation between blood pressure rhythm and blood pressure variability with white matter lesions.

Material/Methods

A total of 144 subjects aged 40 to 80 years underwent MRI scanning to assess the degree of white matter lesions using the Fazekas scale. The regional cerebral blood flow was detected by brain perfusion imaging, and an ambulatory blood pressure monitor was used to measure the circadian blood pressure rhythm. Odds ratio and the 95% confidence interval was computed using logistics regression analysis. The relationship between various factors and blood pressure was calculated by curve simulation.

Results

With the increase of white matter lesions, the regional cerebral blood flow at the lesion decreased gradually. Systolic blood pressure day/night difference ratio (OR=0.815, 95% CI 0.729–0.910), diastolic blood pressure day/night difference ratio (OR=0.895, 95% CI 0.831–0.964), systolic blood pressure coefficient of variation (OR=1.589, 95% CI 1.273–1.983), and diastolic blood pressure coefficient of variation (OR=1.363, 95% CI 1.150–1.616) were significantly associated with Fazekas score (P<0.05 for all).

Conclusions

Greater blood pressure variability and blood pressure rhythm disorders were associated with lower regional cerebral blood flow in patients with white matter lesions.

Clinical importance of high- sensitivity troponin T in patients without coronary artery disease

Cardiac troponin is the preferred biomarker for the diagnosis of the acute coronary syndrome (ACS), but many other diseases can be identified with elevated troponin levels in the absence of ACS. The recent development of a high-sensitive cardiac troponin T (hs-cTnT) assay permits the detection of very low levels of cTnT. The use of hs-cTnT assay has emerged as a tool for identifying high-risk individuals for primary preventive treatment and can detect subclinical injury in asymptomatic patients. Hs-cTnT analyses are generally related to ischemia in the literature. Thus, we made an evaluation of hs-cTnT analysis in non-coronary patients, which may contribute to the literature.

Prognostic Significance of Neuroadrenergic Dysfunction for Cardiovascular Events in Patients With Acute Myocardial Infarction

BACKGROUND

The dysregulation of systemic blood pressure (BP) variation or cardiac neuroadrenergic dysfunction is associated with adverse cardiovascular events. We aimed to clarify the prognostic significance of neuroadrenergic dysfunction for cardiovascular events in patients with acute myocardial infarction (AMI).

METHODS AND RESULTS

We enrolled 63 AMI patients (mean age, 67±12 years) underwent ambulatory BP monitoring (ABPM) and cardiac iodine-(123)metaiodobenzylguanidine (MIBG) imaging within 4 weeks after AMI onset. We analyzed the circadian BP pattern and heart-to-mediastinum (H/M) MIBG uptake ratio. All the patients were followed for 2 years. The study endpoint was a composite of major adverse cardiovascular events, including all-cause death, MI, coronary revascularization except for the MI culprit lesion, and stroke. Patients with a non-dipper pattern (n=29) or an H/M ratio <1.96 (n=28) had a worse prognosis than those with either a dipper pattern (n=34) or an H/M ratio ≥1.96 (n=35; log-rank, P=0.013 and 0.010, respectively). Patients with both a non-dipper pattern and an H/M ratio <1.96 (n=12) had a significantly worse prognosis than did the other patients (P=0.0020).

CONCLUSIONS

Dysregulation of BP variation and cardiac MIBG uptake were associated with cardiovascular events following AMI. Examining ABPM with MIBG imaging may potentially improve risk stratification in these patients.

The Relationship between Non-Dipper Blood Pressure and Thoracic Aortic Diameter in Metabolic Syndrome

OBJECTIVE

Non-dipper hypertension is associated with increased cardiovascular morbidity and mortality. The purpose of this study was to evaluate the association of non-dipping hypertension with aortic diameter in patients with metabolic syndrome.

MATERIALS AND METHODS

This study included 70 hypertensive patients with metabolic syndrome. These patients were evaluated with 24-h blood pressure Holter monitoring and divided into two groups of 35 patients each. Aortic diameter was measured by M-mode and two-dimensional echocardiography. These parameters were compared between the two groups.

RESULTS

In the dipper group, there were 26 female and 9 male patients with a mean age of 55±11 years. In the non-dipper group, there were 25 female and 10 male patients with a mean age of 56±11 years. No significant difference was found between the two groups in terms of basic characteristics. Non-dipper hypertensive patients had a higher thoracic aortic diameter value than dipper patients (35.6±2.4 and 33.23±1.1, p<0.01).

CONCLUSION

These findings suggest that thoracic aortic diameter value is higher in patients with non-dipper hypertension.

Comparison of subclinical left and right ventricular systolic dysfunction in non-dipper and dipper hypertensives: impact of isovolumic acceleration

Abstract Objectives: To evaluate subclinical left ventricular and right ventricular systolic impairment in dipper and non-dipper hypertensives by using isovolumic acceleration.

METHODS

About 45 normotensive healthy volunteers (20 men, mean age 43 ± 9 years), 45 dipper (27 men, mean age 45 ± 9 years) and 45 non-dipper (25 men, 47 ± 7 years) hypertensives were enrolled. Isovolumic acceleration was measured by dividing the peak myocardial isovolumic contraction velocity by isovolumic acceleration time.

RESULTS

Non-dippers indicated lower left ventricular (2.2 ± 0.4 m/s(2) versus 2.8 ± 1.0 m/s(2), p < 0.01) and right ventricular isovolumic acceleration values (2.8 ± 0.8 m/s(2) versus 3.5 ± 1.0 m/s(2), p = 0.012) compared with dippers. Left ventricular mass index (p = 0.001), interventricular septal thickness (p = 0.002) and myocardial performance index (p < 0.001) were negatively correlated with left ventricular isovolumic acceleration. Left ventricular septal thickness (p = 0.002), mass index (p = 0.001) and right ventricular myocardial performance index (p < 0.001) were negatively correlated with right ventricular isovolumic acceleration.

CONCLUSION

The present study demonstrates that non-dipper hypertensives have increased left and right ventricular subclinical systolic dysfunction compared with dippers. Isovolumic acceleration is the only echocardiographic parameter in predicting this subtle impairment.

Evaluation of carotid intima-media thickness and aortic elasticity in patients with nondipper hypertension

BACKGROUND

The relationship between cardiovascular diseases and the diurnal blood pressure (BP) rhythm was researched in many studies. It has been demonstrated that the nondipping pattern has been associated with target organ damage and worsened cardiovascular outcomes. The aim of our study was to assess the relationship between aortic elasticity parameters and carotid intima-media thickness (CIMT) and diastolic dysfunction in terms of "dipper" and "nondipper" hypertension subtypes.

METHODS

A total of 60 hypertensive patients without known coronary heart disease were recruited to our study. All patients were classified as "dipper" or "nondipper" after ambulatory BP follow-up. Patients' left ventricular (LV) systolic and diastolic functions were assessed with transthoracic echocardiography. Ascending aorta diameters and CIMT were measured by ultrasonography and the elasticity parameters of aorta were calculated by using relevant formula.

RESULTS

There were no significant differences between the groups with respect to demographic, biochemical data, and cardiovascular risk factors. Aortic stiffness was significantly increased in nondippers, whereas aortic strain and distensibility were significantly decreased (P = 0.005, P = 0.005, and P = 0.024, respectively). Carotid artery IMT was significantly increased in nondippers compared to dippers (P = 0.013). A significant correlation was noted between CIMT and mean BP. No significant difference was detected between 2 groups in terms of LV hypertrophy and diastolic dysfunction.

CONCLUSION

In our study, we showed that impairment of aortic elasticity parameters and increase in CIMT as a predictor of end organ damage were more often in the nondipper hypertensive patients.

Correlation between Proximal Abdominal Aortic Stiffness Measured by Ultrasound and Brachial-Ankle Pulse Wave Velocity

Background and Objectives

The proximal portion of the abdominal aorta (AA) is characterized by minimal arteriosclerosis compared with other aortic segments. To assess the clinical usefulness of this characteristic, the correlation between ultrasonographically measured proximal AA stiffness and brachial-ankle pulse wave velocity (baPWV) was examined.

Subjects and Methods

285 subjects were analyzed, half with hypertension and half with normal blood pressure. Proximal AA was examined using ultrasonography; strain, distensibility, elastic modulus, and the stiffness index were determined. After adjustment for age, gender, body mass index (BMI), systolic blood pressure (SBP), and heart rate, the relationships between baPWV and all these parameters were tested.

Results

The mean age of the study subjects was 58.1±12.8 years and the mean BMI was 24.3±3.8 kg/cm². 58.9% of the subjects were female. 42.8% were hypertensive subjects. Among the hypertensive subjects, 56.0% were taking antihypertensive medication. Adjusted partial correlation coefficients for the relationship between baPWV with strain, distensibility, elastic modulus, and the stiffness index of the proximal AA were -0.203 (p=0.01), -0.121 (p=0.129), 0.304 (p=0.0001), and 0.299 (p=0.0001), respectively, in normotensive subjects. In the multivariate analyses, such correlations were observed mainly in the normotensive group, whereas there was no association among hypertensive subjects regardless of antihypertensive medication status.

Conclusion

baPWV is moderately correlated with the stiffness parameters for the proximal AA, mainly in normotensive subjects.

The effect of non-dipper and dipper blood pressure patterns on aortic elasticity in patients with metabolic syndrome

The purpose of this study was to evaluate the effect of blood pressure (BP) rhythm on aortic functions in patients with metabolic syndrome. Seventy patients with newly diagnosed hypertension who fulfilled the metabolic syndrome criteria according to the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (NCEP/ATP-III) were evaluated with 24-hour BP holter monitoring. According to BP rhythm, 35 patients with dipper BP pattern and 35 patients with non-dipper BP pattern were enrolled as two groups in our study. Systolic and diastolic diameters of the ascending aorta were measured by M-mode echocardiography and aortic functions (aortic strain, distensibility, and stiffness index) were calculated. The nocturnal systolic and diastolic BPs were significantly higher in non-dipper patients than the dipper group. According to clinical parameters including age, gender, height, weight, body mass index, waist circumference, clinical systolic, and diastolic BPs, we did not find significantly difference between the two groups. Aortic strain was significantly higher (6.63 ± 3.37 vs. 1.81 ± 0.92; P < .0001) and aortic distensibility was lower (2.38 ± 1.18 cm(-2)/dyn/10(-6) and 6.66 ± 3.67 cm(-2)/dyn/10(-6); P < .001) in non-dipper group. These findings suggest that aortic functions were prominently deteriorated in non-dipper hypertensive patients than dippers with metabolic syndrome.

Peripheral Augmentation Index is Associated With the Ambulatory Arterial Stiffness Index in Patients With Hypertension

Background

Vascular dysfunction is highly prevalent if not ubiquitous in patients with hypertension. We compared two different measures of vascular function obtained from digital volume waveforms with measures of ventricular-vascular load derived from 24-hour blood pressure (BP) recordings in patients with hypertension.

Methods

Digital pulsatile volume waveforms were captured via plethysmography (peripheral arterial tone, PAT) and used to derive augmentation index (a measure of ventricular-vascular coupling) and the pulse wave amplitude-reactive hyperemia index (a measure of microvascular reactivity). Ambulatory arterial stiffness index (AASI) and the BP variability ratio (BPVR) were derived from 24-hour ambulatory BP recordings.

Results

There was a positive association between PAT-AIx and AASI (r = 0.52, P < 0.05). There was also a positive association between PAT-AIx and BPVR (r = 0.37, P < 0.05). PAT-AIx was not associated with PWA-RHI (r = -0.14, P > 0.05). PWA-RHI was not associated with AASI or BPVR (P > 0.05).

Conclusions

PAT-AIx is associated with ambulatory measures of vascular function and may offer clinical insight into vascular burden and cardiovascular disease risk in patients with hypertension independent of information obtained from PWA-RHI.

The effects of nocturnal dipping on cardiovascular outcomes and proteinuria in essential hypertensive patients

Individuals who do not have a 10% to 20% reduction in blood pressure (BP) during the night are known as ‘nondippers’. Non-dipping patterns in hypertensive patients have been shown to be associated with an excess of target organ damage and other adverse outcomes. The present study was designed to investigate the relationship between nocturnal BP pattern, defined on the basis of the ambulatory blood pressure monitoring (ABPM) recording, and cardiac and renal target organ damage in a population of at least one year treated essential hypertensive subjects. The present analysis involved 123 patients with treated essential hypertension attending the outpatient clinic of our centre. Each patient was subjected to the following procedures: blood sampling for routine blood chemistry, spot urine for proteinuria, 24-hour periods of ABPM, and echocardiography. In the ABPM period, a dipping pattern was observed in 65 of the 123 patients, and a non-dipping pattern in 58 patients. Body mass index was higher in the non-dippers (26 ± 4 versus 28 ± 4, p<0.05). The proteinuria in spot urine was significantly higher in the non-dippers (10 ± 6 versus 24 ± 48, p<0.03). Left ventricular mass, interventricular septum thickness, posterior wall thickness and left ventricular systolic diameter were significantly higher in the non-dippers compared to the dippers. Left ventricular diastolic function was similar in non-dipper cases, except E-wave deceleration time. In treated essential hypertensives the blunted or absent nocturnal fall in blood pressure can be a strong predictor of cardiac and renal events. Hypertensive patients should be evaluated by ambulatory blood pressure monitoring. To prevent patients at risk for morbidity and mortality casualities as a result of hypertension, patients should be evaluated by ambulatory blood pressure monitoring. This method can be utilized for exacting future follow-ups with the patient.

Impaired coronary microvascular and left ventricular diastolic functions in patients with ankylosing spondylitis

BACKGROUND

It has been shown that the patients with inflammatory rheumatic diseases such as systemic lupus erythematosus and rheumatoid arthritis have an increased risk of developing atherosclerosis. However, the association of ankylosing spondylitis (AS) to atherosclerosis and related diseases is still controversial. Accordingly, we investigated coronary flow reserve (CFR) and left ventricular (LV) diastolic function in patients with AS using transthoracic Doppler echocardiography.

METHODS

CFR and LV diastolic function were studied in 40 patients with AS (38.9+/-10.2 years, 26 males) and 35 healthy volunteers (37.5+/-6.4 years, 23 males). Coronary diastolic peak flow velocities (DPFV) were measured at baseline and after dipyridamole infusion. CFR was calculated as the ratio of hyperemic to baseline DPFV. LV diastolic function was assessed by both standard and tissue Doppler imaging.

RESULTS

Demographic features and coronary risk factors except diastolic blood pressure were similar between the groups. CFR were significantly lower in the AS group than in the control group (2.20+/-0.46 versus 3.02+/-1.50, P<0.0001). Reflecting LV diastolic function mitral A-wave and E/A ratio were borderline significant, and mitral E-wave deceleration time and isovolumic relaxation time were significantly different between the groups. Serum hsCRP and TNF-alpha levels were significantly higher in the patients with AS, and hsCRP and TNF-alpha levels independently correlated with CFR.

CONCLUSION

These findings show that CFR reflecting coronary microvascular function and LV diastolic function are impaired in patients with AS, and severity of these impairments correlate well with hsCRP and TNF-alpha. These results suggest that impaired CFR may be an early manifestation of cardiac involvement in patients with AS.

Nondipping blood pressure patterns among individuals with essential hypertension: a review of the literature

BACKGROUND

Researchers have discovered that blood pressure (BP) varies in a diurnal manner throughout a 24-hour period, being higher during the day and lower at night. Most people have a dipping BP pattern characterized by a nighttime BP that is 10-20% lower than their daytime BP. Individuals who experience a less than 10% reduction in nighttime BP are described as having a nondipping BP pattern. Although controversial, there is a growing body of evidence suggesting that a nondipping BP pattern is associated with a greater risk of target organ damage among individuals with essential hypertension.

AIM

To review the literature on the most common factors associated with nondipping BP patterns among individuals with essential hypertension.

METHODS

CINAHL (1982-March 2006), PubMed (1950-March 2006) and Cochrane Library (1966-March 2006) databases were searched using the keywords: dipper, dipping, nondipper, nondipping, ambulatory blood pressure monitoring, ABPM, hypertension, essential hypertension, high blood pressure, blood pressure, nocturnal blood pressure, nighttime blood pressure, diurnal blood pressure, and blood pressure patterns. Published studies, abstracts, dissertations as well as the reference lists of retrieved articles were reviewed. Studies were included if they involved subjects with only treated or untreated essential hypertension or those with samples of both nomotensive and treated or untreated essential hypertensive individuals. Additionally, studies needed to evaluate 24-hour, daytime and nighttime BP patterns.

RESULTS

There is some evidence to suggest advanced age, African-American ethnicity, female sex, postmenopausal status, sodium sensitivity, sleep apnea, sleep quality, anger, hostility, depression, stress, social support, and socioeconomic status have an association with nondipping BP patterns.

CONCLUSION

Knowledge of the potential factors associated with an altered nighttime BP pattern is of importance because it can help identify persons at risk for nondipping BP patterns and potential target organ damage. Furthermore, knowledge of these factors associated with a nondipping BP profile will lay the foundation for interventions to prevent/treat alterations in nighttime BP patterns.