***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    ***EXAMPLES*** 
    Input: Background —Arterial distensibility measures , generally from pulse-wave velocity ( PWV ) , are widely used with little knowledge of relationships to patient outcome . We tested whether aortic PWV predicts cardiovascular and all-cause mortality in type 2 diabetes and glucose-tolerance – tested ( GTT ) multiethnic population sample s. Methods and Results — Participants were r and omly sample d from ( 1 ) a type 2 diabetes outpatient clinic and ( 2 ) primary care population registers , from which nondiabetic control subjects were given a GTT .  Brachial blood pressures  and Doppler-derived aortic PWV  were measured . Mortality data over 10 years ’ follow-up were obtained . At any level of systolic blood pressure ( SBP ) , aortic PWV was greater in subjects with diabetes than in controls . Mortality risk doubled in subjects with diabetes ( hazard ratio 2.34 , 95 % CI 1.5 to 3.74 ) and in those with glucose intolerance ( 2.12 , 95 % CI 1.11 to 4.0 ) compared with controls . For all groups combined , age , sex , and SBP predicted mortality ; the addition of PWV independently predicted all-cause and cardiovascular mortality ( hazard ratio 1.08 , 95 % CI 1.03 to 1.14 for each 1 m/s increase ) but displaced SBP . Glucose tolerance status and smoking were other independent contributors , with African-Caribbeans experiencing reduced mortality risk ( hazard ratio 0.41 , 95 % CI 0.25 to 0.69 ) . Conclusions —Aortic PWV is a powerful independent predictor of mortality in both diabetes and GTT population sample s. In displacing SBP as a prognostic factor , aortic PWV is probably further along the causal pathway for arterial disease and may represent a useful integrated index of vascular status and hence cardiovascular risk AIMS Increased arterial wave reflections are associated with the presence and extent of coronary atherosclerosis and with cardiovascular mortality in selected population s. We prospect ively evaluated their prognostic value in the short- and long-term following percutaneous coronary interventions ( PCIs ) . METHODS AND RESULTS We non-invasively quantified wave reflections [ expressed as augmentation index corrected for heart rate of 75 b.p.m . ( AIx@75 ) ] using applanation tonometry of the radial artery and a vali date d transfer function to obtain the corresponding aortic values in 262 patients undergoing PCI .  During 2-year follow-up , 61 patients reached the primary endpoint [ death , myocardial infa rct ion ( MI ) , and restenosis ] . Increasing tertiles of Alx@75 were related to the rate of patients reaching the primary endpoint [ 15.2 , 20 and 35.3 % , respectively ( P = 0.001 ) ] , as well as the secondary endpoints total mortality , myocardial infa rct ion and death plus myocardial infa rct ion ( RR for the third vs. the first tertile 4.33 , 3.25 and 3.46 , respectively , P < 0.05 ) . In a multivariable Cox-regression model , AIx@75 added prognostic value above and beyond clinical risk factors , angiographic variables , and medications ( RR 1.8 , 95%CI 1.18 - 2.76 per increasing AIx@75-tertile , P < 0.01 ) . CONCLUSION Increased arterial wave reflections are independently associated with an increased risk for severe short- and long-term cardiovascular events in patients undergoing PCI Isolated systolic hypertension is an important risk factor for cardiovascular disease and results primarily from elastic artery stiffening . Although various drug therapies are used to lower peripheral blood pressure ( BP ) in patients with isolated systolic hypertension , the effects of the 4 major classes of antihypertensive agents on central BP , pulse pressure ( PP ) amplification , and arterial stiffness in this condition are not clear . Fifty-nine patients over the age of 60 years with untreated isolated systolic hypertension ( systolic BP ≥140 mm Hg and diastolic BP ≤90 mm Hg ) were r and omly assigned to receive 1 of the following 4 antihypertensive agents : perindopril , atenolol , lercanidipine , or bendrofluazide  . BP was measured using a mercury sphygmomanometer , and augmentation index and carotid-femoral ( aortic ) pulse wave velocity were measured at baseline , after 2 weeks of placebo therapy , and at the end of 10 weeks of active therapy . Peripheral systolic BP and peripheral PP were reduced similarly after treatment with all 4 classes of drug . However , central PP was only reduced significantly by perindopril , lercanidipine , and bendrofluazide , whereas atenolol had no effect . Lercanidipine reduced the augmentation index , whereas atenolol increased it . Aortic pulse wave velocity was not changed by any of the drugs . In summary , despite similar reductions in peripheral systolic and PPs with the 4 classes of drug , changes in central pressure and augmentation index varied . Because central PP and increased wave reflections are considered important risk factors in patients with isolated systolic hypertension , the choice of therapy may be influenced by these findings in the future We compared the effect of losartan ( 50 mg/day ) to hydrochlorthiazide ( 12.5 mg/day ) on blood pressure ( BP )  and arterial stiffness in 11 untreated hypertensive patients aged 47 to 69 years in a 4-week single blind r and omized crossover study with an intervening 4-week washout period . Both drugs produced a significant ( P < .001 ) and similar decrease in brachial BP . Only losartan induced a significant decrease in arterial wave reflection ( P < .0001 ) , with a preferential reduction in aortic ( P < .001 ) compared to brachial pulse pressure . Losartan also significantly increased pulse pressure amplification and reduced pulse wave velocity . These results suggest that an AT(1 ) receptor antagonist induces a BP independent decrease in aortic stiffness and arterial wave reflection Recent studies have suggested a differential influence of mean pressure and pulse pressure on myocardial infa rct ion and stroke , and differences among the major drugs in their efficacy at preventing these individual endpoints . We hypothesized that antihypertensive drugs have differing influences upon the pulse wave even when their effects on blood pressure are the same . We studied 30 untreated hypertensive patients , aged 28 - 55 years , who were rotated through six 6-week periods of daily treatment with amlodipine 5 mg , doxazosin 4 mg , lisinopril 10 mg , bisoprolol 5 mg , bendrofluazide 2.5 mg or placebo . The best drug was repeated at the end of the rotation . Blood pressure readings and radial pulse tonometry ( by Sphygmocor ) were performed at each visit , and blood was taken for measurement of levels of atrial natriuretic peptide and brain natriuretic peptide ( BNP ) . The Sphygmocor derivation of the central aortic pulse wave was used to measure time for transmission of the reflected wave ( T(R ) ) and the augmentation index ( AI ) , which is the proportional increase in systolic pressure due to the reflected wave . There was a dissociation between the effects of the drugs on blood pressure and pulse wave analysis .  Bisoprolol caused the greatest falls in blood pressure and T(R ) , but was the only drug to increase AI . This paradoxical response to bisoprolol was associated with a 3-fold increase in plasma BNP levels . There was a smaller elevation of BNP in women compared with men , as described previously , and this elevation also was associated with significantly higher values of AI . Other drugs reduced AI , and this was associated with a significant decrease in BNP by amlodipine . In conclusion , antihypertensive drugs differ in their short-term effects on augmentation of the systolic pulse wave and secretion of BNP from the heart , regarded as a sensitive measure of strain on cardiomyocytes . These differences may help to explain cause-specific differences in outcome in recent trials BACKGROUND The objective of this study was to examine the association of Joint National Committee ( JNC-V ) blood pressure and National Cholesterol Education Program ( NCEP ) cholesterol categories with coronary heart disease ( CHD ) risk , to incorporate them into coronary prediction algorithms , and to compare the discrimination properties of this approach with other noncategorical prediction functions . METHODS AND RESULTS This work was design ed as a prospect i ve , single-center study in the setting of a community-based cohort . The patients were 2489 men and 2856 women 30 to 74 years old at baseline with 12 years of follow-up . During the 12 years of follow-up , a total of 383 men and 227 women developed  CHD , which was significantly associated with categories of blood pressure , total cholesterol , LDL cholesterol , and HDL cholesterol ( all P<.001 ) . Sex-specific prediction equations were formulated to predict CHD risk according to age , diabetes , smoking , JNC-V blood pressure categories , and NCEP total cholesterol and LDL cholesterol categories . The accuracy of this categorical approach was found to be comparable to CHD prediction when the continuous variables themselves were used . After adjustment for other factors , approximately 28 % of CHD events in men and 29 % in women were attributable to blood pressure levels that exceeded high normal ( > or = 130/85 ) . The corresponding multivariable-adjusted attributable risk percent associated with elevated total cholesterol ( > or = 200 mg/dL ) was 27 % in men and 34 % in women . CONCLUSIONS Recommended guidelines of blood pressure , total cholesterol , and LDL cholesterol effectively predict CHD risk in a middle-aged white population sample . A simple coronary disease prediction algorithm was developed using categorical variables , which allows physicians to predict multivariate CHD risk in patients without overt CHD Background Antihypertensive agents can reduce arterial stiffness . We hypothesized that an angiotensin receptor blocker ( ARB ) irbesartan and an angiotensin converting enzyme inhibitor ( ACEI ) lisinopril improved arterial compliance . Methods A r and omized , double-blind , double-dummy , controlled crossover trial . Fifteen hypertensive patients , mean age 65.5 ± 8.9 years ( mean ± SD ) were given irbesartan ( 150 to 300 mg/day ) or lisinopril ( 10 to 20 mg/day ) for 12 weeks and then crossed over for 12 weeks . Pulse wave velocity ( PWV ) in the carotid-femoral ( CF ) , carotid-radial ( CR ) , and femoral dorsalis-pedis ( FD ) were measured using a Complior ® PWV system . Results After 12 weeks , systolic blood pressure ( SBP ) decreased from 162.4 ± 12.9 to 134.5 ± 14.8 with irbesartan and to 145.2 ± 25 mmHg with lisinopril . Irbesartan and lisinopril  reduced PWV ( CF ) in the elastic arterial system from 15.1 ± 5 to 13.3 ± 2.6 ( p < 0.005 ) and to 14 ± 4.7 ( p < 0.05 ) m/s respectively ( p = 0.345 ) . Irbesartan reduced PWV ( CR ) and PWV ( FD ) , whereas lisinopril did not . The difference between treatments was significant after SBP adjustment ( p = 0.037 for PWV ( CR ) and p < 0.001 for PWV ( FD ) ) . Conclusions Irbesartan improved arterial compliance in elastic and muscular arteries , whereas lisinopril improved it only in elastic arteries Background — Few population studies addressed the prognostic significance of aortic pulse wave velocity ( APWV ) above and beyond other cardiovascular risk factors . Methods and Results — We studied a sex- and age-stratified r and om sample of 1678 Danes aged 40 to 70 years . We used Cox regression to investigate the prognostic value of  APWV , office pulse pressure ( PP ) , and 24-hour ambulatory PP  while adjusting for mean arterial pressure ( MAP ) and other covariates . Over a median follow-up of 9.4 years , the incidence of fatal and nonfatal cardiovascular end points , cardiovascular mortality , and fatal and nonfatal coronary heart disease amounted to 154 , 62 , and 101 cases , respectively . We adjusted for sex , age , body mass index , MAP measured in the office ( conventional PP and APWV ) or by ambulatory monitoring ( 24-hour PP ) , smoking , and alcohol intake . With these adjustments , APWV maintained its prognostic significance in relation to each end point ( P<0.05 ) , whereas office and 24-hour PP lost their predictive value ( P>0.19 ) , except for office PP in relation to coronary heart disease ( P=0.02 ) . For each 1-SD increment in 
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Our data suggested that ARBs had a similar effect as other anti-hypertensive agents in reducing ba-PWV and cf-PWV .
Upon systematic review , the renin-angiotensin-axis system mechanism seems more significant than the direct vessel dilatation system in anti-arterial stiffness mechanism .