Instruct: Given a scientific claim, retrieve documents that support or refute the claim.
Query: Decreased diastolic blood pressure (DBP) is associated with abdominal aortic aneurysm.
BACKGROUND The associations of blood pressure with the different manifestations of incident cardiovascular disease in a contemporary population have not been compared. In this study, we aimed to analyse the associations of blood pressure with 12 different presentations of cardiovascular disease. METHODS We used linked electronic health records from 1997 to 2010 in the CALIBER (CArdiovascular research using LInked Bespoke studies and Electronic health Records) programme to assemble a cohort of 1·25 million patients, 30 years of age or older and initially free from cardiovascular disease, a fifth of whom received blood pressure-lowering treatments. We studied the heterogeneity in the age-specific associations of clinically measured blood pressure with 12 acute and chronic cardiovascular diseases, and estimated the lifetime risks (up to 95 years of age) and cardiovascular disease-free life-years lost adjusted for other risk factors at index ages 30, 60, and 80 years. This study is registered at ClinicalTrials.gov, number NCT01164371. FINDINGS During 5·2 years median follow-up, we recorded 83,098 initial cardiovascular disease presentations. In each age group, the lowest risk for cardiovascular disease was in people with systolic blood pressure of 90-114 mm Hg and diastolic blood pressure of 60-74 mm Hg, with no evidence of a J-shaped increased risk at lower blood pressures. The effect of high blood pressure varied by cardiovascular disease endpoint, from strongly positive to no effect. Associations with high systolic blood pressure were strongest for intracerebral haemorrhage (hazard ratio 1·44 [95% CI 1·32-1·58]), subarachnoid haemorrhage (1·43 [1·25-1·63]), and stable angina (1·41 [1·36-1·46]), and weakest for abdominal aortic aneurysm (1·08 [1·00-1·17]). Compared with diastolic blood pressure, raised systolic blood pressure had a greater effect on angina, myocardial infarction, and peripheral arterial disease, whereas raised diastolic blood pressure had a greater effect on abdominal aortic aneurysm than did raised systolic pressure. Pulse pressure associations were inverse for abdominal aortic aneurysm (HR per 10 mm Hg 0·91 [95% CI 0·86-0·98]) and strongest for peripheral arterial disease (1·23 [1·20-1·27]). People with hypertension (blood pressure ≥140/90 mm Hg or those receiving blood pressure-lowering drugs) had a lifetime risk of overall cardiovascular disease at 30 years of age of 63·3% (95% CI 62·9-63·8) compared with 46·1% (45·5-46·8) for those with normal blood pressure, and developed cardiovascular disease 5·0 years earlier (95% CI 4·8-5·2). Stable and unstable angina accounted for most (43%) of the cardiovascular disease-free years of life lost associated with hypertension from index age 30 years, whereas heart failure and stable angina accounted for the largest proportion (19% each) of years of life lost from index age 80 years. INTERPRETATION The widely held assumptions that blood pressure has strong associations with the occurrence of all cardiovascular diseases across a wide age range, and that diastolic and systolic associations are concordant, are not supported by the findings of this high-resolution study. Despite modern treatments, the lifetime burden of hypertension is substantial. These findings emphasise the need for new blood pressure-lowering strategies, and will help to inform the design of randomised trials to assess them. FUNDING Medical Research Council, National Institute for Health Research, and Wellcome Trust.
BACKGROUND Damage to large arteries is a major factor in the high cardiovascular morbidity and mortality of patients with end-stage renal disease (ESRD). Increased arterial stiffness and intima-media thickness, together with increased pulse pressure, are the principal arterial alterations. Whether increased aortic pulse-wave velocity (PWV), a classic marker of increased arterial stiffness, may predict all-cause and/or cardiovascular mortality has never been investigated. METHODS AND RESULTS A cohort of 241 patients with ESRD undergoing hemodialysis was studied between April 1987 and April 1998. The mean duration of follow-up was 72+/-41 months (mean+/-SD). Mean age at entry was 51.5+/-16.3 years. Seventy-three deaths occurred, including 48 cardiovascular and 25 noncardiovascular fatal events. At entry, together with standard clinical and biochemical analyses, patients underwent echocardiography and aortic PWV measured by Doppler ultrasonography. On the basis of Cox analyses, 2 factors emerged as predictors of all-cause and cardiovascular mortality: age and aortic PWV. Hemoglobin and low diastolic pressure interfered to a smaller extent. After adjustment for all the confounding factors, an OR for PWV >12. 0 versus <9.4 m/s was 5.4 (95% CI, 2.4 to 11.9) for all-cause mortality and 5.9 (95% CI, 2.3 to 15.5) for cardiovascular mortality. For each PWV increase of 1 m/s in our study population, all-cause mortality-adjusted OR was 1.39 (95% CI, 1.19 to 1.62). CONCLUSIONS These results provide the first direct evidence that in patients with ESRD, increased aortic stiffness determined by measurement of aortic PWV is a strong independent predictor of all-cause and mainly cardiovascular mortality.
Epidemiological studies demonstrate that a lower blood pressure and decline in blood pressure over months or years are associated with higher mortality in dialysis patients. In contrast, randomized, controlled trials lack power to establish benefits of antihypertensive therapy. Patients on long-term dialysis participating in randomized, controlled trials and receiving antihypertensive drug therapy were the subject of this meta-analysis. Outcomes assessed were the hazard ratio of cardiovascular events and all-cause mortality in treated group compared with controls. Among 1202 patients who we identified in 5 studies, the overall benefit of antihypertensive therapy compared with the control or placebo group had a combined hazard ratio for cardiovascular events of 0.69 (95% CI: 0.56 to 0.84) using a fixed-effects model and 0.62 (95% CI: 0.45 to 0.86) using a random-effects model. In a sensitivity analysis, we found that the hypertensive group had a pooled hazard ratio of 0.49 (95% CI: 0.35 to 0.67), but when normotensives were included in the trial, lesser cardiovascular protection was seen (pooled hazard ratio of 0.86 [95% CI: 0.67 to 1.12]). Test for heterogeneity between hypertensive and "normotensive-included" groups was significant (P<0.006). Similar results were seen for risk ratio for death and cardiovascular events. There was evidence of publication bias based on Egger's test and funnel plot. Randomized trials suggested a benefit of antihypertensive therapy among hemodialysis patients. Adequately powered randomized trials are required to confirm these observations, especially among those with hypertension.
Accumulated evidence suggests that an altered ambulatory blood pressure (BP) profile, particularly elevated nighttime BP, reflects target organ injury and is a better predictor of further cardiorenal risk than the clinic BP or daytime BP in hypertensive patients complicated by chronic kidney disease (CKD). In this study, we examined the beneficial effects of olmesartan, an angiotensin II type 1 receptor blocker (ARB), on ambulatory BP profiles and renal function in hypertensive CKD patients. Forty-six patients were randomly assigned to the olmesartan add-on group (n=23) or the non-ARB group (n=23). At baseline and after the 16-week treatment period, ambulatory BP monitoring was performed and renal function parameter measurements were collected. Although the baseline clinic BP levels and the after-treatment/baseline (A/B) ratios of clinic BP levels were similar in the olmesartan add-on and non-ARB groups, the A/B ratios of ambulatory 24-h and nighttime BP levels in the olmesartan add-on group were significantly lower. Furthermore, the A/B ratios of urinary protein, albumin and type IV collagen excretion in the olmesartan add-on group were significantly lower than those in the non-ARB group (urinary protein excretion, 0.72±0.41 vs. 1.45±1.48, P=0.030; urinary albumin excretion, 0.73±0.37 vs. 1.50±1.37, P=0.005; urinary type IV collagen excretion, 0.87±0.42 vs. 1.48±0.87, P=0.014) despite comparable A/B ratios for the estimated glomerular filtration rate in the two groups. These results indicate that in hypertensive patients with CKD, olmesartan add-on therapy improves the ambulatory BP profile via a preferential reduction in nighttime BP with concomitant renal injury inhibition.
Strict blood pressure (BP) control is reportedly important for the management of hypertensive patients with chronic kidney disease (CKD). The purpose of this cross-sectional study was to examine whether the variables of ambulatory BP and the heart rate (HR) profile, central hemodynamics, and arterial stiffness were closely related to the renal function parameters (urine albumin excretion rate [UACR] and estimated glomerular filtration rate [eGFR]) observed in 25 consecutive hospitalized hypertensive patients with CKD. There were significant positive relationships between UACR and 24-hour, daytime, and nighttime ambulatory systolic BP. In addition, there were significant negative relationships between UACR and 24-hour and daytime HR variability. The circulating B-type natriuretic peptide level and hemoglobin A1c were also positively related to UACR. With respect to eGFR, although the 24-hour and nighttime HR variability were positively associated with eGFR, the circulating pentosidine and nighttime HR had a negative relationship with eGFR. On the other hand, central hemodynamics and arterial stiffness did not exhibit any significant association with renal function parameters. These results indicate that ambulatory BP and the HR profile are closely modulated by renal function deterioration. Further studies are needed to investigate the causal relationship between ambulatory BP and the HR profile and renal function parameters in hypertensive patients with CKD.
Muscle sympathetic nerve activity is increased during normotensive pregnancy while mean arterial pressure is maintained or reduced, suggesting baroreflex resetting. We hypothesized spontaneous sympathetic baroreflex gain would be reduced in normotensive pregnant women relative to nonpregnant matched controls. Integrated muscle sympathetic burst incidence and total sympathetic activity (microneurography), blood pressure (Finometer), and R-R interval (ECG) were assessed at rest in 11 pregnant women (33 ± 1 wk gestation, 31 ± 1 yr, prepregnancy BMI: 23.5 ± 0.9 kg/m(2)) and 11 nonpregnant controls (29 ± 1 yr; BMI: 25.2 ± 1.7 kg/m(2)). Pregnant women had elevated baseline sympathetic burst incidence (43 ± 2 vs. 33 ± 2 bursts/100 heart beats, P = 0.01) and total sympathetic activity (1,811 ± 148 vs. 1,140 ± 55 au, P < 0.01) relative to controls. Both mean (88 ± 3 vs. 91 ± 2 mmHg, P = 0.4) and diastolic (DBP) (72 ± 3 vs. 73 ± 2 mmHg, P = 0.7) pressures were similar between pregnant and nonpregnant women, respectively, indicating an upward resetting of the baroreflex set point with pregnancy. Baroreflex gain, calculated as the linear relationship between sympathetic burst incidence and DBP, was reduced in pregnant women relative to controls (-3.7 ± 0.5 vs. -5.4 ± 0.5 bursts·100 heart beats(-1)·mmHg(-1), P = 0.03), as was baroreflex gain calculated with total sympathetic activity (-294 ± 24 vs. -210 ± 24 au·100 heart beats(-1)·mmHg(-1); P = 0.03). Cardiovagal baroreflex gain (sequence method) was not different between nonpregnant controls and pregnant women (49 ± 8 vs. 36 ± 8 ms/mmHg; P = 0.2). However, sympathetic (burst incidence) and cardiovagal gains were negatively correlated in pregnant women (R = -0.7; P = 0.02). Together, these data indicate that the influence of the sympathetic nervous system over arterial blood pressure is reduced in normotensive pregnancy, in terms of both long-term and beat-to-beat regulation of arterial pressure, likely through a baroreceptor-dependent mechanism.
OBJECTIVE To assess the antihypertensive efficacy of olmesartan medoxomil and ramipril on 24-h ambulatory blood pressure (ABP) in elderly hypertensive patients by pooled data analysis of two studies with identical designs (one Italian, one European). METHODS After a 2-week placebo wash-out 1453 elderly hypertensive patients (65-89 years; sitting office DBP 90-109 mmHg and/or sitting office SBP 140-179 mmHg) were randomized to a 12-week double-blind treatment with olmesartan medoxomil 10 mg or ramipril 2.5 mg once-daily, up-titrated (20 and 40 mg olmesartan medoxomil; 5 and 10 mg ramipril) after 2 and 6 weeks in patients without normalized office BP. 24-h ABP was recorded at randomization and after 12 weeks. RESULTS In 715 patients with valid baseline and end-of-treatment recordings baseline-adjusted 24-h SBP and DBP reductions were greater with olmesartan medoxomil (n = 356) than with ramipril (n = 359) [between-treatment differences and 95% confidence interval (CI), SBP: 2.2 (3.8, 0.6), P = 0.006; DBP: 1.3 (2.2, 0.3), P = 0.009]. Olmesartan medoxomil showed larger BP reductions in the last 6 h from the dosing interval and higher smoothness indices than ramipril. Olmesartan medoxomil reduced the SBP morning rise [-2.8 (-4.9, -0.8) mmHg], whereas ramipril did not [+1.5 (-0.6, +3.6) mmHg; P = 0.004 between-treatments]. Five hundred and eighty-two patients with sustained hypertension (office and 24-h ambulatory hypertension) showed the largest antihypertensive effect, with between-treatment differences still in favor of olmesartan medoxomil [SBP: 2.1 (3.9, 0.4), P = 0.019; DBP: 1.2 (2.3, 0.1), P = 0.032]. CONCLUSIONS Olmesartan medoxomil provides a more effective and sustained 24-h BP control than ramipril in elderly hypertensive patients, particularly in the hours farthest from last intake.
In adult patients with CKD, hypertension is linked to the development of left ventricular hypertrophy, but whether this association exists in children with CKD has not been determined conclusively. To assess the relationship between BP and left ventricular hypertrophy, we prospectively analyzed data from the Chronic Kidney Disease in Children cohort. In total, 478 subjects were enrolled, and 435, 321, and 142 subjects remained enrolled at years 1, 3, and 5, respectively. Echocardiograms were obtained 1 year after study entry and then every 2 years; BP was measured annually. A linear mixed model was used to assess the effect of BP on left ventricular mass index, which was measured at three different visits, and a mixed logistic model was used to assess left ventricular hypertrophy. These models were part of a joint longitudinal and survival model to adjust for informative dropout. Predictors of left ventricular mass index included systolic BP, anemia, and use of antihypertensive medications other than angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. Predictors of left ventricular hypertrophy included systolic BP, female sex, anemia, and use of other antihypertensive medications. Over 4 years, the adjusted prevalence of left ventricular hypertrophy decreased from 15.3% to 12.6% in a systolic BP model and from 15.1% to 12.6% in a diastolic BP model. These results indicate that a decline in BP may predict a decline in left ventricular hypertrophy in children with CKD and suggest additional factors that warrant additional investigation as predictors of left ventricular hypertrophy in these patients.
BACKGROUND Patients with signs and symptoms of heart failure and a normal left ventricular ejection fraction are said to have diastolic heart failure. It has traditionally been thought that the pathophysiological cause of heart failure in these patients is an abnormality in the diastolic properties of the left ventricle; however, this hypothesis remains largely unproven. METHODS We prospectively identified 47 patients who met the diagnostic criteria for definite diastolic heart failure; all the patients had signs and symptoms of heart failure, a normal ejection fraction, and an increased left ventricular end-diastolic pressure. Ten patients who had no evidence of cardiovascular disease served as controls. Left ventricular diastolic function was assessed by means of cardiac catheterization and echocardiography. RESULTS The patients with diastolic heart failure had abnormal left ventricular relaxation and increased left ventricular chamber stiffness. The mean (+/-SD) time constant for the isovolumic-pressure decline (tau) was longer in the group with diastolic heart failure than in the control group (59+/-14 msec vs. 35+/-10 msec, P=0.01). The diastolic pressure-volume relation was shifted up and to the left in the patients with diastolic heart failure as compared with the controls. The corrected left ventricular passive-stiffness constant was significantly higher in the group with diastolic heart failure than in the control group (0.03+/-0.01 vs. 0.01+/-0.01, P<0.001). CONCLUSIONS Patients with heart failure and a normal ejection fraction have significant abnormalities in active relaxation and passive stiffness. In these patients, the pathophysiological cause of elevated diastolic pressures and heart failure is abnormal diastolic function.
BACKGROUND Common carotid intima media thickness (CIMT) and ankle brachial pressure index (ABPI) are used as surrogate marker of atherosclerosis, and have been shown to correlate with arterial stiffness, however their correlation with global atherosclerotic burden has not been previously assessed. We compare CIMT and ABPI with atheroma burden as measured by whole body magnetic resonance angiography (WB-MRA). METHODS 50 patients with symptomatic peripheral arterial disease were recruited. CIMT was measured using ultrasound while rest and exercise ABPI were performed. WB-MRA was performed in a 1.5T MRI scanner using 4 volume acquisitions with a divided dose of intravenous gadolinium gadoterate meglumine (Dotarem, Guerbet, FR). The WB-MRA data was divided into 31 anatomical arterial segments with each scored according to degree of luminal narrowing: 0 = normal, 1 = <50%, 2 = 50-70%, 3 = 70-99%, 4 = vessel occlusion. The segment scores were summed and from this a standardized atheroma score was calculated. RESULTS The atherosclerotic burden was high with a standardised atheroma score of 39.5±11. Common CIMT showed a positive correlation with the whole body atheroma score (β 0.32, p = 0.045), however this was due to its strong correlation with the neck and thoracic segments (β 0.42 p = 0.01) with no correlation with the rest of the body. ABPI correlated with the whole body atheroma score (β -0.39, p = 0.012), which was due to a strong correlation with the ilio-femoral vessels with no correlation with the thoracic or neck vessels. On multiple linear regression, no correlation between CIMT and global atheroma burden was present (β 0.13 p = 0.45), while the correlation between ABPI and atheroma burden persisted (β -0.45 p = 0.005). CONCLUSION ABPI but not CIMT correlates with global atheroma burden as measured by whole body contrast enhanced magnetic resonance angiography in a population with symptomatic peripheral arterial disease. However this is primarily due to a strong correlation with ilio-femoral atheroma burden.
CONTEXT Managing thoracic aortic aneurysms identified incidentally by increased use of computed tomography, echocardiography, and magnetic resonance imaging is problematic, especially in the elderly. OBJECTIVE To ascertain whether the previously reported poor prognosis for individuals with thoracic aortic aneurysms has changed with better medical therapies and improved surgical techniques that can now be applied to aneurysm management. DESIGN Population-based cohort study. SETTING AND PATIENTS All 133 patients with the diagnosis of degenerative thoracic aortic aneurysms among Olmsted County, Minnesota, residents between 1980 and 1994 compared with a previously reported cohort of similar patients between 1951 and 1980. MAIN OUTCOME MEASURES The primary clinical end points were incidence, cumulative rupture risk, rupture risk as a function of aneurysm size, and survival. RESULTS In contrast to abdominal aortic aneurysms, for which men are affected predominately, 51% of thoracic aortic aneurysms were identified in women who were considerably older at recognition than men (mean age, 75.9 vs 62.8 years, respectively; P= .01). The overall incidence rate of 10.4 per 100000 person-years (95% confidence interval [CI], 8.6-12.2) between 1980 and 1994 was more than 3-fold higher than the rate from 1951 to 1980. The cumulative risk of rupture was 20% after 5 years. Seventy-nine percent of ruptures occurred in women (P= .01). The 5-year risk of rupture as a function of aneurysm size at recognition was 0% for aneurysms less than 4 cm in diameter, 16% (95% CI, 4%-28%) for those 4 to 5.9 cm, and 31% (95% CI, 5%-56%) for aneurysms 6 cm or more. Overall 5-year survival improved to 56% (95% CI, 48%-66%) between 1980 and 1994 compared with only 19% between 1951 and 1980 (P<.01). CONCLUSIONS In this population, elderly women represent an increasing portion of all patients with clinically recognized thoracic aortic aneurysms and constitute the majority of patients whose aneurysm eventually ruptures. Overall survival for thoracic aortic aneurysms has improved significantly in the past 15 years.
BACKGROUND Epidemiologic analysis of family data on blood pressure (BP) is often compromised by the effects of antihypertensive medications. A review of numerous clinical trials that investigated the effects of BP-lowering medications is summarized here. METHODS Published clinical trials, including 137 clinical trials with monodrug therapies and 28 clinical trials of combination drug therapies with a total of 11,739 participants, were reviewed from PubMed. Six major classes/groups of antihypertensive medications were categorized by ethnicity, including angiotensin-converting enzyme (ACE) inhibitors, alpha1-blockers, cardioselective beta-blockers (beta1-blockers), calcium channel blockers, thiazide and thiazide-like diuretics, and loop diuretics. RESULTS Using sitting or supine BP, for ethnic groups combined, monodrug therapy with ACE inhibitors showed a weighted average effect of lowering the systolic and diastolic BP by 12.5/9.5 mm Hg; alpha1-blockers by 15.5/11.7 mm Hg; beta1-blockers by 14.8/12.2 mm Hg; calcium channel blockers by 15.3/10.5 mm Hg; thiazide diuretics by 15.3/9.8 mm Hg; and loop diuretics by 15.8/8.2 mm Hg. However, ACE inhibitors, alpha1-blockers, and beta1-blockers were less effective in African Americans than in non-African Americans, whereas calcium channel blockers, thiazide diuretics, and loop diuretics were more effective in African Americans than in non-African Americans. For two-drug combination therapy with ethnic groups combined, the BP-lowering effect of the second medication, when compared to its effect as monodrug therapy, was 84% and 65% for systolic and diastolic BP, respectively. CONCLUSIONS The BP-lowering effects reported here may be used to impute the pretreatment BP levels, which can improve the information content and hence the power of epidemiologic analysis in studies where use of antihypertensive medications is a confounding factor in the BP measurements.
The amount and type of dietary fat have long been associated with the risk of CVD. Arterial stiffness and endothelial dysfunction are important risk factors in the aetiology of CHD. A range of methods exists to assess vascular function that may be used in nutritional science, including clinic and ambulatory blood pressure monitoring, pulse wave analysis, pulse wave velocity, flow-mediated dilatation and venous occlusion plethysmography. The present review focuses on the quantity and type of dietary fat and effects on blood pressure, arterial compliance and endothelial function. Concerning fat quantity, the amount of dietary fat consumed habitually appears to have little influence on vascular function independent of fatty acid composition, although single high-fat meals postprandially impair endothelial function compared with low-fat meals. The mechanism is related to increased circulating lipoproteins and NEFA which may induce pro-inflammatory pathways and increase oxidative stress. Regarding the type of fat, cross-sectional data suggest that saturated fat adversely affects vascular function whereas polyunsaturated fat (mainly linoleic acid (18 : 2n-6) and n-3 PUFA) are beneficial. EPA (20 : 5n-3) and DHA (22 : 6n-3) can reduce blood pressure, improve arterial compliance in type 2 diabetics and dyslipidaemics, and augment endothelium-dependent vasodilation. The mechanisms for this vascular protection, and the nature of the separate physiological effects induced by EPA and DHA, are priorities for future research. Since good-quality observational or interventional data on dietary fatty acid composition and vascular function are scarce, no further recommendations can be suggested in addition to current guidelines at the present time.
OBJECTIVE Corin is a serine protease that converts pro-atrial natriuretic peptide (pro-ANP) to atrial natriuretic peptide (ANP), a cardiac hormone that regulates salt-water balance and blood pressure. ANP is degraded by natriuretic peptide receptor (NPR). This study was to determine if aberrant pro-ANP/corin/NPR signaling is present in maternal vascular system in preeclampsia. STUDY DESIGN Maternal venous blood was obtained from 197 pregnant women (84 normotensive, 16 complicated with chronic hypertension (CHT), 11 mild and 86 severe preeclampsia). Plasma corin and pro-ANP concentrations were measured by enzyme-linked immunosorbent assay. Maternal subcutaneous fat tissue was obtained from 12 pregnant women with cesarean section delivery (6 normotensive and 6 preeclampsia). Vascular ANP and its receptors NPR-A, NPR-B, and NPR-C expression were examined by immunostaining of paraffin embedded subcutaneous fat tissue sections. RESULTS Corin concentrations were significantly higher in mild (2.78 ± 0.67 ng/ml, p < .05) and severe (2.53 ± 0.18 ng/ml, p < .01) preeclampsia than in normotensive (1.58 ± 0.08 ng/ml) and CHT (1.55 ± 0.20 ng/ml) groups. Pro-ANP concentrations were significantly higher in CHT (1.59 ± 0.53 ng/ml, p < .05) and severe preeclampsia (1.42 ± 0.24 ng/ml, p < .01) than in normotensive (0.48 ± 0.06 ng/ml) and mild preeclampsia (0.52 ± 0.09 ng/ml) groups. ANP and NPR-B expression was undetectable in maternal vessels from normotensive and preeclamptic pregnancies, but reduced NPR-A expression and increased NPR-C expression was found in maternal vessel endothelium in preeclampsia. CONCLUSIONS ANP is a vasodilator and NPR-C is a clearance receptor for ANP. The finding of upregulation of NPR-C expression suggests that circulating ANP clearance or degradation is increased in preeclampsia. These results also suggest that pro-ANP/corin/NPR signaling is dominant in the vascular system in preeclampsia.
Chronic kidney disease is accompanied by increased large-artery stiffness, but the relation between glomerular filtration rate within the reference range and central or peripheral arterial stiffness has been understudied. The link between renal function and arterial stiffness was assessed in 305 patients with never-treated essential hypertension (men: 58%; age: 48+/-11 years, blood pressure: 151/95+/-20/11 mm Hg), free from overt cardiovascular disease and with serum creatinine values <1.4 mg/dL (men) and <1.2 mg/dL (women), who underwent noninvasive aortic and upper-limb pulse wave velocity (PWV) determination. Aortic PWV was strongly related to age (r=0.55; P<0.001), whereas upper-limb PWV had a weaker nonlinear relation with age (beta=1.392; P<0.001 for age; beta=-1.312; P<0.001 for age squared) and a weak relation with aortic PWV (r=0.22; P<0.001). Glomerular filtration rate (GFR), estimated according to the Mayo clinic equation for healthy subjects, was inversely correlated with large-artery stiffness, as assessed by aortic PWV (r=-0.34; P<0.001), and with peripheral artery stiffness, as assessed by upper-limb PWV (r=-0.25; P<0.001). In a multivariate linear regression, aortic PWV was independently predicted by age (beta=0.48; P<0.001), mean arterial pressure (beta=0.14; P=0.013), and GFR (beta=-0.13, P=0.029). Upper-limb PWV was predicted by GFR (beta=-0.24; P<0.001) and mean arterial pressure (beta=0.20; P<0.001). We conclude that, in hypertensive patients with normal renal function, an inverse relationship exists between GFR and stiffness of both central elastic and peripheral muscular arteries. These relations are in part independent from the effect of several confounders, including age, sex, and blood pressure values.
BACKGROUND Diabetes mellitus is a major risk factor for adverse outcomes after acute coronary syndromes (ACS). Because this disease may be associated with increased platelet aggregation, we investigated whether diabetic patients with ACS derive particular benefit from platelet glycoprotein (GP) IIb/IIIa receptor inhibition. METHODS AND RESULTS We performed a meta-analysis of the diabetic populations enrolled in the 6 large-scale platelet GP IIb/IIIa inhibitor ACS trials: PRISM, PRISM-PLUS, PARAGON A, PARAGON B, PURSUIT, and GUSTO IV. Among 6458 diabetic patients, platelet GP IIb/IIIa inhibition was associated with a significant mortality reduction at 30 days, from 6.2% to 4.6% (OR 0.74; 95% CI 0.59 to 0.92; P=0.007). Conversely, 23 072 nondiabetic patients had no survival benefit (3.0% versus 3.0%). The interaction between platelet GP IIb/IIIa inhibition and diabetic status was statistically significant (P=0.036). Among 1279 diabetic patients undergoing percutaneous coronary intervention (PCI) during index hospitalization, the use of these agents was associated with a mortality reduction at 30 days from 4.0% to 1.2% (OR 0.30; 95% CI 0.14 to 0.69; P=0.002). CONCLUSIONS This meta-analysis, including the entire large-scale trial experience of intravenous platelet GP IIb/IIIa inhibitors for the medical management of non-ST-segment-elevation ACS, shows that these agents may significantly reduce mortality at 30 days in diabetic patients. Although not based on a randomized assessment, the survival benefit appears to be of greater magnitude in patients undergoing PCI. Therefore, the use of platelet GP IIb/IIIa inhibitors should be strongly considered in diabetic patients with ACS.
In the rat isolated perfused kidney, arachidonic acid elicits cyclooxygenase-dependent vasoconstriction through activation of PGH2/TxA2 receptors; responses are enhanced in kidneys from diabetic rats. This study examined the roles of cyclooxygenase-1/cyclooxygenase-2 in the enhanced renal vasoconstrictor effect of arachidonic acid in streptozotocin-diabetic rats. Release of 20-HETE was also determined, as this eicosanoid has been reported to elicit cyclooxygenase-dependent vasoconstriction. We confirmed that vasoconstrictor responses to arachidonic acid were enhanced in the diabetic rat kidney associated with a 2-fold-greater increase in the release of 6-ketoPGF1alpha, which was used as an index of cyclooxygenase activity. One and three micrograms of arachidonic acid increased perfusion pressure by 85+/-37 and 186+/-6 mm Hg, respectively, in diabetic rat kidneys compared with 3+/-1 and 17+/-8 mm Hg, respectively, in control rat kidneys. Inhibition of both cyclooxygenase isoforms with indomethacin (10 micromol/L) abolished the vasoconstrictor response to arachidonic acid in both diabetic and control rat kidneys, whereas inhibition of cyclooxygenase-2 with nimesulide (5 micromol/L) reduced perfusion pressure responses to 1 and 3 microg arachidonic acid only in the diabetic rat kidney to 15+/-8 and 108+/-26 mm Hg, respectively, consistent with a 3-fold increase in the renal cortical expression of cyclooxygenase-2. 20-HETE release from the diabetic rat kidney was reduced almost 6-fold and was not increased in response to arachidonic acid. These results demonstrate that the renal vasoconstrictor effect of arachidonic acid is solely dependent on cyclooxygenase activity, with no evidence for a contribution from 20-HETE; in the diabetic rat, cyclooxygenase-2 activity contributes to the renal vasoconstrictor effect of arachidonic acid.
BACKGROUND Direct recordings from peripheral sympathetic nerves have shown an increased sympathetic drive in pregnancy-induced hypertension (PIH) and preeclampsia (PE). It is unknown whether sympathetic drive is altered in normal pregnancy, when arterial blood pressure can be normal or relatively low. The aim of this study was to measure and compare peripheral sympathetic discharge, its vasoconstrictor effect and its baroreceptor control, during pregnancy and postpartum in women with normal pregnancy (NP) and PIH and in normotensive nonpregnant (NN) women. METHODS AND RESULTS Twenty-one women with NP, 18 women with PIH, and 21 NN women had muscle sympathetic nerve activity assessed from multiunit discharges (MSNA) and from single units with defined vasoconstrictor properties (s-MSNA). The s-MSNA in NP (38+/-6.6 impulses/100 beats) was greater (P<0.05) than in NN women (19+/-1.8 impulses/100 beats) despite similar age and body weight but less than in PIH women (P<0.001) (146+/-23.5 impulses/100 beats). MSNA followed a similar trend. Cardiac baroreceptor reflex sensitivity (BRS) was impaired in NP and PIH women relative to NN. After delivery, sympathetic activity decreased to values similar to those obtained in NN, and there was an increase in BRS. In women with NP, the decrease in sympathetic output occurred despite an insignificant change in blood pressure. CONCLUSIONS Central sympathetic output was increased in women with normal pregnancy and was even greater in the hypertensive pregnant group. The findings suggest that the moderate sympathetic hyperactivity during the latter months of normal pregnancy may help to return the arterial pressure to nonpregnant levels, although when the increase in activity is excessive, hypertension may ensue.
Baseline neurovascular transduction is reduced in normotensive pregnancy; however, little is known about changes to neurovascular transduction during periods of heightened sympathetic activation. We tested the hypothesis that, despite an exacerbated muscle sympathetic nerve activity (microneurography) response to cold pressor stimulation, the blunting of neurovascular transduction in normotensive pregnant women would result in similar changes in vascular resistance and mean arterial pressure (Finometer) relative to nonpregnant controls. Baseline neurovascular transduction was reduced in pregnant women relative to controls when expressed as the quotient of both total resistance and mean arterial pressure and sympathetic burst frequency (0.32±0.07 versus 0.58±0.16 mm Hg/L/min/bursts/min, P<0.001 and 2.4±0.7 versus 3.6±0.8 mm Hg/bursts/min, P=0.001). Sympathetic activation was greater across all 3 minutes of cold pressor stimulation in the pregnant women relative to the nonpregnant controls. Peak sympathoexcitation was also greater in pregnant than in nonpregnant women, whether expressed as sympathetic burst frequency (+17±13 versus +7±8 bursts/min, P=0.049), burst incidence (+17±9 versus +6±11 bursts/100 hb, P=0.03), or total activity (+950±660 versus +363±414 arbitrary units, P=0.04). However, neurovascular transduction during peak cold pressor-induced sympathoexcitation remained blunted in pregnant women (0.25±0.11 versus 0.45±0.08 mm Hg/L/min/bursts/min, P<0.001 and 1.9±1.0 versus 3.2±0.9 mm Hg/bursts/min, P=0.006). Therefore, mean arterial pressure (93±21 versus 99±6 mm Hg, P=0.4) and total peripheral resistance (12±3 versus 14±3 mm Hg/L/min) were not different between pregnant and nonpregnant women during peak sympathoexcitation. These data indicate that the third trimester of normotensive pregnancy is associated with reductions in neurovascular transduction, which result in the dissociation of sympathetic outflow from hemodynamic outcomes, even during cold pressor-induced sympathoexcitation.
Blood pressure variability is one of the characteristic features of hypertension in the elderly. However, its clinical significance remains to be determined. We therefore examined the impact of blood pressure variability on the development of cardiovascular events in elderly hypertensive patients. A total of 106 consecutive hypertensive patients aged more than 60 years old (mean age, 73.9 +/- 8.1 years old; male, 54%), all of whom underwent 24-h ambulatory blood pressure monitoring, were followed up (median, 34 months; range, 3-60 months). During the follow-up period, 39 cardiovascular events were observed, including 14 cases of cerebral infarction and 7 cases of acute myocardial infarction. The coefficient of variation (CV) of 24-h systolic blood pressure (SBP) values was used as an index of blood pressure variability. The patients showed a mean CV value of 10.6%, and were divided into two groups according to this mean value as a cut-off point: a high CV group (n = 46) and a low CV group (n = 60). Although baseline clinical characteristics were similar in the two groups, Kaplan-Meier plots for event-free survival revealed that the rate of cardiovascular events was significantly higher in high CV group than in low CV group (p < 0.05). Cox's proportional hazards analysis showed that increased blood pressure variability (a high CV value of 24-h SBP) was an independent predictive variable for cardiovascular events. The CV value of daytime SBP and the SD value of both 24-h SBP and daytime SBP also had positive correlations with the onset of cardiovascular events. These results suggest that increased blood pressure variability may be an independent risk factor for cardiovascular events in elderly hypertensive patients.
QT intervals were measured over RR intervals ranging from 500 ms to 1000 ms in 13 normal male subjects, 13 male diabetic subjects without and 13 with autonomic neuropathy. There was a close linear relationship between QT and RR in all subjects. The slope of the regression line was significantly greater in the autonomic neuropathy group than the normal group. Thirty-two male diabetic subjects with varying degrees of autonomic dysfunction had repeat QT measurements 3 (range 2–6) years later. QT and QTC lengthened significantly at the second visit, unrelated to age or time between recordings, but which corresponded with changes in autonomic function. Of 71 male diabetic subjects under 60 years followed for 3 years, 13 had died, 8 unexpectedly. Of those with autonomic neuropathy, QT and QTC were significantly longer in those who subsequently died, despite similar ages and duration of diabetes. We conclude that QT/RR interval relationships are altered in diabetic autonomic neuropathy, and that changes in QT length with time parallel changese in autonomic function. There may be an association between QT interval prolongation and the risk of dying unexpectedly in diabetic autonomic neuropathy.
BACKGROUND Angiotensin receptor blockers (ARB) and angiotensin converting enzyme (ACE) inhibitors are known to reduce proteinuria. Their combination might be more effective than either treatment alone, but long-term data for comparative changes in renal function are not available. We investigated the renal effects of ramipril (an ACE inhibitor), telmisartan (an ARB), and their combination in patients aged 55 years or older with established atherosclerotic vascular disease or with diabetes with end-organ damage. METHODS The trial ran from 2001 to 2007. After a 3-week run-in period, 25 620 participants were randomly assigned to ramipril 10 mg a day (n=8576), telmisartan 80 mg a day (n=8542), or to a combination of both drugs (n=8502; median follow-up was 56 months), and renal function and proteinuria were measured. The primary renal outcome was a composite of dialysis, doubling of serum creatinine, and death. Analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00153101. FINDINGS 784 patients permanently discontinued randomised therapy during the trial because of hypotensive symptoms (406 on combination therapy, 149 on ramipril, and 229 on telmisartan). The number of events for the composite primary outcome was similar for telmisartan (n=1147 [13.4%]) and ramipril (1150 [13.5%]; hazard ratio [HR] 1.00, 95% CI 0.92-1.09), but was increased with combination therapy (1233 [14.5%]; HR 1.09, 1.01-1.18, p=0.037). The secondary renal outcome, dialysis or doubling of serum creatinine, was similar with telmisartan (189 [2.21%]) and ramipril (174 [2.03%]; HR 1.09, 0.89-1.34) and more frequent with combination therapy (212 [2.49%]: HR 1.24, 1.01-1.51, p=0.038). Estimated glomerular filtration rate (eGFR) declined least with ramipril compared with telmisartan (-2.82 [SD 17.2] mL/min/1.73 m(2)vs -4.12 [17.4], p<0.0001) or combination therapy (-6.11 [17.9], p<0.0001). The increase in urinary albumin excretion was less with telmisartan (p=0.004) or with combination therapy (p=0.001) than with ramipril. INTERPRETATION In people at high vascular risk, telmisartan's effects on major renal outcomes are similar to ramipril. Although combination therapy reduces proteinuria to a greater extent than monotherapy, overall it worsens major renal outcomes.
Anorectic drugs have been used for more than 30 years as an aid in weight reduction for obese persons. The use of aminorex, an amphetamine analog that increases norepinephrine levels in the central nervous system, led to an epidemic of primary pulmonary hypertension (PPH) in Europe in the late 1960s and early 1970s. The use of fenfluramine and later dexfenfluramine [drugs that inhibit 5-hydroxytryptamine (5-HT) release and reuptake and increases 5-HT and thus 5-HT secretion in the brain] was associated with a second epidemic of PPH. All of these drugs have been voluntarily withdrawn from the market. The pathogenesis of PPH in patients treated with these agents is uncertain, but recent evidence suggests that potassium channel abnormalities and vasoactive and proliferative properties of 5-HT may play a role. There is increasing experimental evidence suggesting that aminorex, fenfluramine and dexfenfluramine inhibit 4-aminopyridine-sensitive currents in potassium channels resulting in vasoconstriction in pulmonary resistance vessels and perhaps smooth muscle cell proliferation. 5-HT causes pulmonary artery vasoconstriction and smooth muscle cell proliferation. Its levels are known to be high in those with fenfluramine-induced PPH. However, a firm cause-and-effect relationship has not yet been established. One potentially beneficial effect of the epidemics of anorectic-related PPH is that it may have provided important insights into the causes of PPH unrelated to anorectic agents.
New-onset diabetes mellitus (NOD) refers to forms of diabetes mellitus that develop during the therapeutic processes of other diseases such as hypertension. This study has been conducted in a network meta-analysis to compare antihypertensive drugs by identifying both the advantages and disadvantages on NOD by focusing on their respective effect rates. Odd ratios and corresponding 95% confidence intervals or credible intervals were calculated within pairwise and network meta-analysis. A total of 38 articles with 224 140 patients were included to evaluate the preventive effect of hypertension drugs on NOD. From the network meta-analysis it was evident that both angiotensin-converting enzyme inhibitor as well as angiotensin receptor blocker treatments are associated with a lower risk of developing NOD compared with placebo, with ranking probabilities of 79.81% and 72.77%, respectively, while β-blockers and calcium channel blockers may significantly increase the probability of developing NOD (β-blockers: odds ratio, 2.18 [95% credible intervals: 1.36-3.50]; calcium channel blockers: odds ratio, 1.16 [95% credible intervals, 1.05-1.29]). In conclusion, angiotensin receptor blockers have an advantage over the other treatments regarding the NOD.
Sympathetic activity has been reported to increase in normotensive pregnant women, and to be even greater in women with gestational hypertension and preeclampsia at term. Whether sympathetic overactivity develops early during pregnancy, remaining high throughout gestation, or whether it only occurs at term providing the substrate for hypertensive disorders is unknown. We tested the hypothesis that sympathetic activation occurs early during pregnancy in humans. Eleven healthy women (29 ± 3 (SD) years) without prior hypertensive pregnancies were tested during the mid-luteal phase (PRE) and early pregnancy (EARLY; 6.2 ± 1.2 weeks of gestation). Muscle sympathetic nerve activity (MSNA) and haemodynamics were measured supine, at 30 deg and 60 deg upright tilt for 5 min each. Blood samples were drawn for catecholamines, direct renin, and aldosterone. MSNA was significantly greater during EARLY than PRE (supine: 25 ± 8 vs. 14 ± 8 bursts min(-1), 60 deg tilt: 49 ± 14 vs. 40 ± 10 bursts min(-1); main effect, P < 0.05). Resting diastolic pressure trended lower (P = 0.09), heart rate was similar, total peripheral resistance decreased (2172 ± 364 vs. 2543 ± 352 dyne s cm(-5); P < 0.05), sympathetic vascular transduction was blunted (0.10 ± 0.05 vs. 0.36 ± 0.47 units a.u.(-1) min(-1); P < 0.01), and both renin (supine: 27.9 ± 6.2 vs. 14.2 ± 8.7 pg ml(-1), P < 0.01) and aldosterone (supine: 16.7 ± 14.1 vs. 7.7 ± 6.8 ng ml(-1), P = 0.05) were higher during EARLY than PRE. These results suggest that sympathetic activation is a common characteristic of early pregnancy in humans despite reduced diastolic pressure and total peripheral resistance. These observations challenge conventional thinking about blood pressure regulation during pregnancy, showing marked sympathetic activation occurring within the first few weeks of conception, and may provide the substrate for pregnancy induced cardiovascular complications.