human
***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 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Increased arterial stiffness , as estimated from aortic pulse wave velocity ( Ao-PWV ) , and albuminuria are independent predictors for cardiovascular disease in type 2 diabetes mellitus ( T2DM ) . Whether angiotensin receptor blockers ( ARBs ) , drugs with cardio-renal protective effects , improve Ao-PWV to a greater extent than other equipotent antihypertensive medications remains unclear . After a 4-week washout phase , we compared the effects of valsartan ( n=66 ) , an ARB , with that of amlodipine ( n=65 ) , a calcium channel blocker on Ao-PWV in 131 T2DM patients with pulse pressure ( PP ) ≥60 mm Hg and raised albumin excretion rate ( AER ) in a 24-week r and omized , double-blind , parallel group study . Hydrochlorothiazide ( HCTZ ) 25 mg/d was added to valsartan 160 mg and amlodipine 5 mg/od uptitrated to 10 mg/od after 4 weeks to ensure equivalent BP control . After 24 weeks brachial and central aortic PP had fallen to a similar extent with attained mean ( SD ) brachial and central PP of 61.6 ( 13.6 ) and 47.3 ( 14.1 ) mm Hg in the valsartan/HCTZ group and 61.5 ( 12.2 ) and 47.3 ( 9.9 ) mm Hg in the amlodipine group , respectively . Ao-PWV showed a significantly greater reduction , mean ( 95 % CI ) , −0.9 m/s ( −1.4 to −0.3 ) for valsartan/HCTZ compared to amlodipine ( P=0.002 ) . AER fell significantly only with Val/HCTZ from 30.8(20.4 , 46.5 ) to 18.2(12.5 , 26.3 ) mcg/min , ( P=0.01 ) with between treatment difference in favor of Val/HCTZ of −15.3mcg/min ( P<0.001 ) . Changes in AER and Ao-PWV were not correlated . Valsartan/HCTZ improves arterial stiffness and AER to a significantly greater extent than amlodipine despite similar central and brachial BP control . These 2 effects , which appear independent of each other , may explain the specific cardio-renal protective properties of ARBs The renin-angiotensin system ( RAS ) may play a role in vascular aging . The authors hypothesized that blockade of the angiotensin II type 1 receptor with an angiotensin receptor blocker in healthy elderly subjects improves vascular compliance and endothelial function .  Thirty-five healthy elderly subjects were r and omized to valsartan or placebo in a double-blind crossover study after baseline testing for pulse wave velocity , aortic augmentation index , and brachial artery flow-mediated dilation . Angiotensin II type 1 receptor blockade with valsartan improved vascular compliance but not flow-mediated dilation . Changes in pulse wave velocity with valsartan were correlated with change in central systolic blood pressure and pulse pressure and remained associated on multivariate analysis . Change in pulse wave velocity after adjusting for degree of blood pressure change , age , and sex remained correlated with assignment to the angiotensin receptor blocker but not placebo . These data suggest that angiotensin II type 1 receptor blockade improves aging-related vascular compliance without alterations in flow-mediated dilation . Mechanisms regulating compliance and endothelial function are complex and may not necessarily converge in aging Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more Renin – angiotensin system ( RAS ) blockers have shown clinical outcomes superior to those of the beta (β)-blocker atenolol , despite similar reductions in the peripheral blood pressure ( BP ) , perhaps because of different impacts on central hemodynamics . However , few comparative studies of RAS blockers and newer vasodilating β-blockers have been performed . We compared the central hemodynamic effects of losartan and carvedilol in a prospect i ve , r and omized , open , blinded end point study . Of the 201 hypertensive patients enrolled , 182 ( 49.6±9.9 years , losartan group=88 and carvedilol group=94 ) were analyzed . Carotid-femoral pulse wave velocity ( cfPWV ) , aortic augmentation index ( AIx ) , AIx corrected for a heart rate ( HR ) of 75 beats per minute ( AIx@HR75 ) and central BP were measured noninvasively at baseline and after a 24-week treatment regimen with losartan or carvedilol . After 24 weeks , there were no between-group differences in the brachial BP , cfPWV , AIx@HR75 or central BP changes , except for a more favorable AIx effect with losartan . The changes in all measured metabolic and inflammatory parameters were also not significantly different between the two groups , except for uric acid . Losartan and carvedilol showed generally comparable effects on central hemodynamic indices , metabolic profile , inflammatory parameters and peripheral arterial pressure with a 24-week treatment Objective . Angiotensin-converting enzyme ( ACE ) inhibitors have been shown to lower central augmentation index ( cAI ) , an index of arterial wave reflection , more than β-blockers . We tested whether this is also true for long-term treatment with an angiotensin receptor blocker ( ARB ) . Methods . One-hundred and fifty-six subjects with essential hypertension were r and omised to treatment with either irbesartan or atenolol .  cAI and central blood pressure ( BP ) were determined by pulse wave analysis from the radial and the carotid artery after six and after 18 months treatment . Results . Peripheral and central systolic and diastolic BP were reduced to a similar extent A in the two groups . cAI was reduced with irbesartan , but increased with atenolol ( derived from the carotid artery : -6±10 vs. -4±12 % after six months , p<0.001 ; —4±12 vs. + 1±11 % after 18 months ; p=0.011 ) . Furthermore , central to peripheral pulse pressure ( PP ) amplification was unaffected by treatment with irbesartan , but decreased with atenolol . Conclusions . Although treatment with irbesartan and atenolol  similarly decreased peripheral and central BP , only treatment with irbesartan had beneficial effects on arterial wave reflection and preserved PP amplification . These haemodynamic effects may at least partly explain the reported differential effects of ARB versus β-blocker treatment on cardiovascular mortality in patients with essential hypertension When observed in elderly hypertensive patients , increased pulse pressure ( PP ) and arterial stiffness are known to be independent risk factors for cardiovascular diseases . Increased systolic blood pressure ( SBP ) leads to left ventricular hypertrophy , while decreased diastolic blood pressure ( DBP ) results in decreased coronary circulation . It is known that increased arterial stiffness is the major cause of increased PP . Thus basic morbid states of cardiac failure or ischemic heart diseases are more likely to develop in elderly hypertensive patients with increased PP and arterial stiffness , and there is need of antihypertensive drugs that decrease these effects in elderly hypertensives . In this study , we compared the effects of an angiotensin-receptor blocker ( ARB : valsartan ) , an angiotensin-converting enzyme inhibitor ( ACE-I : temocapril ) , and long-acting Ca antagonists ( L- and N-type Ca channel blocker : cilnidipine ; and L-type Ca channel blocker : nifedipine CR ) on PP and arterial stiffness measured by pulse wave velocity in elderly hypertensive patients for 3 months . The ARB yielded the largest reductions in PP and brachial-ankle pulse wave velocity ( baPWV ) , followed by the ACE-I and L- and N-type Ca channel blocker , while the L-type Ca channel blocker yielded no improvement . The effects on arterial stiffness and PP thus varied among the drug characteristics . Although ARB achieved the largest reduction in baPWV , this decrease was not associated with any reductions in PP , SBP , DBP , or mean blood pressure , as were the baPWV-decreases achieved by the other drugs , suggesting that ARB may further reduce the risk of arteriosclerosis in elderly hypertensive patients by decreasing arterial stiffness in addition to its antihypertensive effect Background Cardiovascular disease ( CVD ) is highly prevalent in patients with chronic kidney disease ( CKD ) . Inhibition of the renin-angiotensinsystem ( RAS ) in hypertension causes differential effects on central and brachial blood pressure ( BP ) , which has been translated into improved outcome . The objective was to examine if a more complete inhibition of RAS by combining an angiotensin converting enzyme inhibitor ( ACEI ) and an angiotensin receptor antagonist ( ARB ) compared to monotherapy has an additive effect on central BP and pulse-wave velocity ( PWV ) , which are known markers of CVD . Methods Sixty-seven CKD patients ( mean GFR 30 , range 13–59 ml/min/1.73 m2 ) participated in an open r and omized study of 16 weeks of monotherapy with either enalapril or c and esartan followed by 8 weeks of dual blockade aim ing at a total dose of 16 mg c and esartan and 20 mg enalapril o.d . Pulse-wave measurements were performed at week 0 , 8 , 16 and 24 by the SphygmoCor device . Results Significant additive BP independent reductions were found after dual blockade in aortic PWV ( −0.3 m/s , P<0.05 ) and in augmentation index ( −2 % , P<0.01 ) compared to monotherapy . Furthermore pulse pressure amplification was improved ( P<0.05 ) and central systolic BP reduced ( −6 mmHg , P<0.01 ) . Conclusions Dual blockade of the RAS result ed in an additive BP independent reduction in pulse-wave reflection and arterial stiffness compared to monotherapy in CKD patients . Trial Registration Clinical trial.gov In spontaneously hypertensive rats resistance artery structure , endothelial dysfunction and geometry-independent wall stiffness were reduced by an angiotensin AT1-receptor antagonist . In previous studies of human hypertension , interruption of the renin-angiotensin system corrected small artery structure and endothelial dysfunction , whereas the β-blocker atenolol did not . We hypothesized that the AT1R antagonist losartan , but not the β-blocker atenolol , would reduce stiffness of gluteal subcutaneous small arteries in essential hypertensive patients . Seventeen untreated mild essential hypertensive patients ( 47±2years ; 75 % male ) were r and omly assigned in double-blind fashion to losartan or atenolol treatment for one year . Small , resistance size arteries were studied on pressurized myographs . Blood pressure ( mmHg ) was reduced ( p<0.01 ) from 145±4/101±2 and 147±6/98±2 to 128±4/86±2 and 131±3/84±1 by losartan and atenolol , respectively . The media/lumen ratio of small arteries was unaffected by atenolol ( 8.3±0.3 % before and 8.8±0.5 % after treatment ) . In contrast , losartan reduced media/lumen ratio from 8.4±0.4 % to 6.7±0.3 % ( p<0.01 ) . Whereas isobaric elastic modulus was unaffected by either treatment , geometry-independent stiffness ( slope of elastic modulus vs. stress ) was reduced from 9.7±1.2 to 6.1±0.9 ( P<0.05 ) under losartan treatment , but was unchanged by atenolol ( 8.2±1.3 to 7.8±0.6 ) . In conclusion , treatment with losartan reduced stiffness and structural alterations of subcutaneous resistance arteries of previously untreated essential hypertensive patients , whereas atenolol failed to do so Background Antihypertensive drugs are used to control blood pressure ( BP ) and reduce macro- and microvascular complications in hypertensive patients with diabetes . Objectives The present study aim ed to compare the functional vascular changes in hypertensive patients with type 2 diabetes mellitus after 6 weeks of treatment with amlodipine or losartan . Methods Patients with a previous diagnosis of hypertension and type 2 diabetes mellitus were r and omly divided into 2 groups and evaluated after 6 weeks of treatment with amlodipine ( 5 mg/day ) or losartan ( 100 mg/day ) . Patient evaluation included BP measurement , ambulatory BP monitoring , and assessment of vascular parameters using applanation tonometry , pulse wave velocity ( PWV ) , and flow-mediated dilation ( FMD ) of the brachial artery 
    Output:
    
agent
The effect of ARB on the improvement of the PWV level is not superior to other types of antihypertensive agents , but ARB is superior to other types of antihypertensive agents for improving the AI level .
Overall , to improve of arterial stiffness , ARB maybe is superior to other antihypertensive agents
***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 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Increased arterial stiffness , as estimated from aortic pulse wave velocity ( Ao-PWV ) , and albuminuria are independent predictors for cardiovascular disease in type 2 diabetes mellitus ( T2DM ) . Whether angiotensin receptor blockers ( ARBs ) , drugs with cardio-renal protective effects , improve Ao-PWV to a greater extent than other equipotent antihypertensive medications remains unclear . After a 4-week washout phase , we compared the effects of valsartan ( n=66 ) , an ARB , with that of amlodipine ( n=65 ) , a calcium channel blocker on Ao-PWV in 131 T2DM patients with pulse pressure ( PP ) ≥60 mm Hg and raised albumin excretion rate ( AER ) in a 24-week r and omized , double-blind , parallel group study . Hydrochlorothiazide ( HCTZ ) 25 mg/d was added to valsartan 160 mg and amlodipine 5 mg/od uptitrated to 10 mg/od after 4 weeks to ensure equivalent BP control . After 24 weeks brachial and central aortic PP had fallen to a similar extent with attained mean ( SD ) brachial and central PP of 61.6 ( 13.6 ) and 47.3 ( 14.1 ) mm Hg in the valsartan/HCTZ group and 61.5 ( 12.2 ) and 47.3 ( 9.9 ) mm Hg in the amlodipine group , respectively . Ao-PWV showed a significantly greater reduction , mean ( 95 % CI ) , −0.9 m/s ( −1.4 to −0.3 ) for valsartan/HCTZ compared to amlodipine ( P=0.002 ) . AER fell significantly only with Val/HCTZ from 30.8(20.4 , 46.5 ) to 18.2(12.5 , 26.3 ) mcg/min , ( P=0.01 ) with between treatment difference in favor of Val/HCTZ of −15.3mcg/min ( P<0.001 ) . Changes in AER and Ao-PWV were not correlated . Valsartan/HCTZ improves arterial stiffness and AER to a significantly greater extent than amlodipine despite similar central and brachial BP control . These 2 effects , which appear independent of each other , may explain the specific cardio-renal protective properties of ARBs The renin-angiotensin system ( RAS ) may play a role in vascular aging . The authors hypothesized that blockade of the angiotensin II type 1 receptor with an angiotensin receptor blocker in healthy elderly subjects improves vascular compliance and endothelial function .  Thirty-five healthy elderly subjects were r and omized to valsartan or placebo in a double-blind crossover study after baseline testing for pulse wave velocity , aortic augmentation index , and brachial artery flow-mediated dilation . Angiotensin II type 1 receptor blockade with valsartan improved vascular compliance but not flow-mediated dilation . Changes in pulse wave velocity with valsartan were correlated with change in central systolic blood pressure and pulse pressure and remained associated on multivariate analysis . Change in pulse wave velocity after adjusting for degree of blood pressure change , age , and sex remained correlated with assignment to the angiotensin receptor blocker but not placebo . These data suggest that angiotensin II type 1 receptor blockade improves aging-related vascular compliance without alterations in flow-mediated dilation . Mechanisms regulating compliance and endothelial function are complex and may not necessarily converge in aging Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more Renin – angiotensin system ( RAS ) blockers have shown clinical outcomes superior to those of the beta (β)-blocker atenolol , despite similar reductions in the peripheral blood pressure ( BP ) , perhaps because of different impacts on central hemodynamics . However , few comparative studies of RAS blockers and newer vasodilating β-blockers have been performed . We compared the central hemodynamic effects of losartan and carvedilol in a prospect i ve , r and omized , open , blinded end point study . Of the 201 hypertensive patients enrolled , 182 ( 49.6±9.9 years , losartan group=88 and carvedilol group=94 ) were analyzed . Carotid-femoral pulse wave velocity ( cfPWV ) , aortic augmentation index ( AIx ) , AIx corrected for a heart rate ( HR ) of 75 beats per minute ( AIx@HR75 ) and central BP were measured noninvasively at baseline and after a 24-week treatment regimen with losartan or carvedilol . After 24 weeks , there were no between-group differences in the brachial BP , cfPWV , AIx@HR75 or central BP changes , except for a more favorable AIx effect with losartan . The changes in all measured metabolic and inflammatory parameters were also not significantly different between the two groups , except for uric acid . Losartan and carvedilol showed generally comparable effects on central hemodynamic indices , metabolic profile , inflammatory parameters and peripheral arterial pressure with a 24-week treatment Objective . Angiotensin-converting enzyme ( ACE ) inhibitors have been shown to lower central augmentation index ( cAI ) , an index of arterial wave reflection , more than β-blockers . We tested whether this is also true for long-term treatment with an angiotensin receptor blocker ( ARB ) . Methods . One-hundred and fifty-six subjects with essential hypertension were r and omised to treatment with either irbesartan or atenolol .  cAI and central blood pressure ( BP ) were determined by pulse wave analysis from the radial and the carotid artery after six and after 18 months treatment . Results . Peripheral and central systolic and diastolic BP were reduced to a similar extent A in the two groups . cAI was reduced with irbesartan , but increased with atenolol ( derived from the carotid artery : -6±10 vs. -4±12 % after six months , p<0.001 ; —4±12 vs. + 1±11 % after 18 months ; p=0.011 ) . Furthermore , central to peripheral pulse pressure ( PP ) amplification was unaffected by treatment with irbesartan , but decreased with atenolol . Conclusions . Although treatment with irbesartan and atenolol  similarly decreased peripheral and central BP , only treatment with irbesartan had beneficial effects on arterial wave reflection and preserved PP amplification . These haemodynamic effects may at least partly explain the reported differential effects of ARB versus β-blocker treatment on cardiovascular mortality in patients with essential hypertension When observed in elderly hypertensive patients , increased pulse pressure ( PP ) and arterial stiffness are known to be independent risk factors for cardiovascular diseases . Increased systolic blood pressure ( SBP ) leads to left ventricular hypertrophy , while decreased diastolic blood pressure ( DBP ) results in decreased coronary circulation . It is known that increased arterial stiffness is the major cause of increased PP . Thus basic morbid states of cardiac failure or ischemic heart diseases are more likely to develop in elderly hypertensive patients with increased PP and arterial stiffness , and there is need of antihypertensive drugs that decrease these effects in elderly hypertensives . In this study , we compared the effects of an angiotensin-receptor blocker ( ARB : valsartan ) , an angiotensin-converting enzyme inhibitor ( ACE-I : temocapril ) , and long-acting Ca antagonists ( L- and N-type Ca channel blocker : cilnidipine ; and L-type Ca channel blocker : nifedipine CR ) on PP and arterial stiffness measured by pulse wave velocity in elderly hypertensive patients for 3 months . The ARB yielded the largest reductions in PP and brachial-ankle pulse wave velocity ( baPWV ) , followed by the ACE-I and L- and N-type Ca channel blocker , while the L-type Ca channel blocker yielded no improvement . The effects on arterial stiffness and PP thus varied among the drug characteristics . Although ARB achieved the largest reduction in baPWV , this decrease was not associated with any reductions in PP , SBP , DBP , or mean blood pressure , as were the baPWV-decreases achieved by the other drugs , suggesting that ARB may further reduce the risk of arteriosclerosis in elderly hypertensive patients by decreasing arterial stiffness in addition to its antihypertensive effect Background Cardiovascular disease ( CVD ) is highly prevalent in patients with chronic kidney disease ( CKD ) . Inhibition of the renin-angiotensinsystem ( RAS ) in hypertension causes differential effects on central and brachial blood pressure ( BP ) , which has been translated into improved outcome . The objective was to examine if a more complete inhibition of RAS by combining an angiotensin converting enzyme inhibitor ( ACEI ) and an angiotensin receptor antagonist ( ARB ) compared to monotherapy has an additive effect on central BP and pulse-wave velocity ( PWV ) , which are known markers of CVD . Methods Sixty-seven CKD patients ( mean GFR 30 , range 13–59 ml/min/1.73 m2 ) participated in an open r and omized study of 16 weeks of monotherapy with either enalapril or c and esartan followed by 8 weeks of dual blockade aim ing at a total dose of 16 mg c and esartan and 20 mg enalapril o.d . Pulse-wave measurements were performed at week 0 , 8 , 16 and 24 by the SphygmoCor device . Results Significant additive BP independent reductions were found after dual blockade in aortic PWV ( −0.3 m/s , P<0.05 ) and in augmentation index ( −2 % , P<0.01 ) compared to monotherapy . Furthermore pulse pressure amplification was improved ( P<0.05 ) and central systolic BP reduced ( −6 mmHg , P<0.01 ) . Conclusions Dual blockade of the RAS result ed in an additive BP independent reduction in pulse-wave reflection and arterial stiffness compared to monotherapy in CKD patients . Trial Registration Clinical trial.gov In spontaneously hypertensive rats resistance artery structure , endothelial dysfunction and geometry-independent wall stiffness were reduced by an angiotensin AT1-receptor antagonist . In previous studies of human hypertension , interruption of the renin-angiotensin system corrected small artery structure and endothelial dysfunction , whereas the β-blocker atenolol did not . We hypothesized that the AT1R antagonist losartan , but not the β-blocker atenolol , would reduce stiffness of gluteal subcutaneous small arteries in essential hypertensive patients . Seventeen untreated mild essential hypertensive patients ( 47±2years ; 75 % male ) were r and omly assigned in double-blind fashion to losartan or atenolol treatment for one year . Small , resistance size arteries were studied on pressurized myographs . Blood pressure ( mmHg ) was reduced ( p<0.01 ) from 145±4/101±2 and 147±6/98±2 to 128±4/86±2 and 131±3/84±1 by losartan and atenolol , respectively . The media/lumen ratio of small arteries was unaffected by atenolol ( 8.3±0.3 % before and 8.8±0.5 % after treatment ) . In contrast , losartan reduced media/lumen ratio from 8.4±0.4 % to 6.7±0.3 % ( p<0.01 ) . Whereas isobaric elastic modulus was unaffected by either treatment , geometry-independent stiffness ( slope of elastic modulus vs. stress ) was reduced from 9.7±1.2 to 6.1±0.9 ( P<0.05 ) under losartan treatment , but was unchanged by atenolol ( 8.2±1.3 to 7.8±0.6 ) . In conclusion , treatment with losartan reduced stiffness and structural alterations of subcutaneous resistance arteries of previously untreated essential hypertensive patients , whereas atenolol failed to do so Background Antihypertensive drugs are used to control blood pressure ( BP ) and reduce macro- and microvascular complications in hypertensive patients with diabetes . Objectives The present study aim ed to compare the functional vascular changes in hypertensive patients with type 2 diabetes mellitus after 6 weeks of treatment with amlodipine or losartan . Methods Patients with a previous diagnosis of hypertension and type 2 diabetes mellitus were r and omly divided into 2 groups and evaluated after 6 weeks of treatment with amlodipine ( 5 mg/day ) or losartan ( 100 mg/day ) . Patient evaluation included BP measurement , ambulatory BP monitoring , and assessment of vascular parameters using applanation tonometry , pulse wave velocity ( PWV ) , and flow-mediated dilation ( FMD ) of the brachial artery 
    Output:
    