Dose-dependent arterial destiffening and inward remodeling after olmesartan in hypertensives with metabolic syndrome

Arterial Destiffening in Previously Untreated Mild Hypertensives After 1 Year of Routine Clinical Management

BACKGROUND

Arterial stiffness, measured with pulse wave velocity (PWV), is now classified as a marker of target organ damage (TOD) alongside left ventricular hypertrophy and moderately increased albuminuria. Interventional studies on treated hypertensive patients have shown that PWV could be improved. Our aim was to assess changes in arterial stiffness after 1 year of routine clinical practice in never-treated hypertensive patients.

PATIENTS AND METHODS

We studied 356 never-treated patients with suspected hypertension. After standard clinical assessment during which presence of TOD was evaluated, hypertension diagnosis was confirmed in 231 subjects who subsequently received standard routine care. Both hypertensive and the 125 controls came back for a follow-up visit after 1 year.

RESULTS

Hypertensive patients were slightly older (46 ± 12 vs. 50 ± 12 years, P < 0.001), with higher mean arterial pressure (MAP)-adjusted PWV compared to controls (8.6 ± 2.0 vs. 8.0 ± 1.7 m/s, P < 0.001) and 47% of them presented 1 or more TOD. After 1 year of treatment, MAP was similar in both groups (94.9 vs. 96.2 mm Hg; P = ns), but adjusted PWV remained significantly higher in the hypertensive patients (7.8 ± 1.4 vs. 8.3 ± 1.7 m/s, P = 0.004). The prevalence of elevated PWV was reduced from 20% to 12%. All antihypertensive drugs achieved the same blood pressure (BP) and PWV reduction with the exception of vasodilating beta-blockers which gave slightly better results probably due to heart rate reduction.

CONCLUSION

BP reduction in newly diagnosed hypertensive patients improves arterial stiffness within a year of real-life clinical practice. Patients with the highest PWV and the largest reduction of BP "destiffened" the most whatever antihypertensive class was used.

Microvascular injury and the kidney in hypertension

Renal macrocirculation participates in the development of arterial hypertension. The elevation in systemic blood pressure (BP) can damage the kidney starting in the microcirculation. Established arterial hypertension impinge upon the large arteries and stiffness develops. As a consequence central BP raises and BP pulsatility appear and contribute to further damage renal microcirculation by direct transmission of the elevated BP.

Effects of Sacubitril/Valsartan Versus Olmesartan on Central Hemodynamics in the Elderly With Systolic Hypertension

Effective treatment of systolic hypertension in elderly patients remains a major therapeutic challenge. A multicenter, double-blind, randomized controlled trial with sacubitril/valsartan (LCZ696), a first-in-class angiotensin receptor neprilysin inhibitor, was conducted to determine its effects versus olmesartan (angiotensin receptor blocker) on central aortic pressures, in elderly patients (aged ≥60 years) with systolic hypertension and pulse pressure >60 mm Hg, indicative of arterial stiffness. Patients (n=454; mean age, 67.7 years; mean seated systolic blood pressure, 158.6 mm Hg; mean seated pulse pressure, 69.7 mm Hg) were randomized to receive once-daily sacubitril/valsartan 200 mg or olmesartan 20 mg, force titrated to double the initial doses after 4 weeks, before primary assessment at 12 weeks. The study extended double-blind treatment for 12 to 52 weeks, during which amlodipine (2.5–5 mg) and subsequently hydrochlorothiazide (6.25–25 mg) were added-on for patients not achieving blood pressure target (<140/90). At week 12, sacubitril/valsartan reduced central aortic systolic pressure (primary assessment) greater than olmesartan by −3.7 mm Hg ( P =0.010), further corroborated by secondary assessments at week 12 (central aortic pulse pressure, −2.4 mm Hg, P <0.012; mean 24-hour ambulatory brachial systolic blood pressure and central aortic systolic pressure, −4.1 mm Hg and −3.6 mm Hg, respectively, both P <0.001). Differences in 24-hour ambulatory pressures were pronounced during sleep. After 52 weeks, blood pressure parameters were similar between treatments ( P <0.002); however, more patients required add-on antihypertensive therapy with olmesartan (47%) versus sacubitril/valsartan (32%; P <0.002). Both treatments were equally well tolerated. The PARAMETER study (Prospective Comparison of Angiotensin Receptor Neprilysin Inhibitor With Angiotensin Receptor Blocker Measuring Arterial Stiffness in the Elderly), for the first time, demonstrated superiority of sacubitril/valsartan versus olmesartan in reducing clinic and ambulatory central aortic and brachial pressures in elderly patients with systolic hypertension and stiff arteries.

Association of Central Arterial Stiffness and Pressure Pulsatility with Mild Cognitive Impairment and Dementia: The Atherosclerosis Risk in Communities Study-Neurocognitive Study (ARIC-NCS)

BACKGROUND

The association of central arterial stiffness and pressure pulsatility with mild cognitive impairment (MCI) and dementia is not well characterized in the population-based setting.

OBJECTIVE

The aim of this study was to quantify the cross-sectional association of arterial stiffness and pressure pulsatility with MCI and dementia among 4,461 older white and black adults from the population-based Atherosclerosis Risk in Communities Study-Neurocognitive Study.

METHODS

We used race-stratified multinomial logistic regression to evaluate associations of percentile cut points of carotid-femoral pulse wave velocity, central systolic blood pressure, central pulse pressure, and pulse pressure amplification with MCI and dementia versus no cognitive impairment.

RESULTS

Among whites, those with carotid-femoral pulse wave velocity or central systolic blood pressure ≥75th percentile had a higher prevalence of MCI compared to participants <75th percentile (conditional odds ratio (OR); 95% confidence interval (CI): 1.27 (1.02, 1.56) and 1.28 (1.04, 1.57), respectively) and those with central pulse pressure ≥75th percentile had a higher prevalence of MCI (OR 1.27 (95% CI: 1.03, 1.58)) and dementia (OR 1.76 (95% CI: 1.06, 2.92) compared to participants <75th percentile. Also among whites, those with pulse pressure amplification ≤25th percentile had a higher prevalence of dementia compared to participants >25th percentile (OR 1.65; (95% CI: 1.01, 2.70). Weaker associations were seen among black participants.

CONCLUSION

Higher arterial stiffness and pulsatility were associated with MCI and dementia in white participants. Longitudinal characterization of the observed associations is warranted to assess whether arterial stiffness and pressure pulsatility predict MCI and dementia among older adults.

The effects of alpha 1-adrenoceptor blockade and angiotensin converting enzyme inhibition on central and brachial blood pressure and vascular reactivity: the doxazosin-ramipril study

We aimed to study whether inhibition of the renin–angiotensin–aldosterone system has effects on vascular structure and function beyond the effects on blood pressure reduction alone. Patients with mild-to-moderate hypertension (n = 61, age 54 ± 12 years, 34% women) received the angiotensin converting enzyme inhibitor ramipril 10 mg or the alpha 1-adrenoceptor blocker doxazosin 8 mg double-blind for 12 weeks. Aortic blood pressure, pulse wave velocity, and augmentation index were assessed by applanation tonometry. Endothelial function was studied by forearm post-ischemic flow mediated vasodilatation and by pulse wave analysis with beta 2-adrenoceptor agonist stimulation. Skin microvascular reactivity was assessed by laser Doppler fluxmetry and iontophoresis. Treatment with doxazosin or ramipril reduced aortic and brachial blood pressures (all P < 0.001), with greater reductions in aortic than brachial systolic blood pressures (P = 0.021) and aortic/brachial pulse pressure ratio (P = 0.005). Compared to doxazosin, ramipril reduced carotid-femoral and carotid-radial pulse wave velocity (both P < 0.05). Forearm endothelial dependent and independent vasodilatation, assessed by post-ischemic flow mediated vasodilatation and glyceryl trinitrate, and by pulse wave analysis remained unchanged by both doxazosin and ramipril. In addition, skin microvascular endothelial dependent (acetylcholine) and independent vasodilatation (sodium nitroprusside) remained unchanged. In conclusion, ramipril reduced indices of aortic stiffness, suggesting that angiotensin converting enzyme inhibitor therapy may have effects beyond blood pressure reduction. However, treatment did not appear to influence endothelial function. Evidence of endothelial dysfunction and its possible improvement by antihypertensive treatment might require more advanced hypertension.

This study is registered at ClinicalTrials.gov (NCT02901977) and at EudraCT (# 2007-000631-25).

Arterial Stiffness: Going a Step Beyond

Interest in arterial stiffness has been fueled by the scientific and clinical implications of its "vicious cycle" relationship with aging and systolic blood pressure. In physical terms, stiffness is the slope of the relationship between an artery's distending pressure and its cross-sectional area or volume. Pulse wave velocity (PWV, in m/s), the most common arterial stiffness indicator, is usually measured by the foot-to-foot time and distance method and is proportional to [stiffness × area (or volume)]1/2 at a given pressure. Its intrinsic pressure dependency and other flaws in current PWV methods limit its utility. In contrast, the arterial stiffness-arterial pressure relationship is near-linear, with a slope β, the exponent of the curvilinear arterial pressure-arterial volume relationship. The concept of arterial stiffening is related to β and describes a more functionally relevant aspect of arterial behavior: the change in stiffness for a given change in pressure. Arterial stiffening can be estimated from the variability of within-individual BP measurements (24-h ambulatory, home BP, or BP measured at different arm heights) and can be expressed as the pulse stiffening ratio (PSR) = [systolic stiffness]/[diastolic stiffness] or the ambulatory arterial stiffness index (AASI or its symmetric form, sAASI). High arterial stiffness (PWV) and stiffening (β, stiffness index, cardio-ankle vascular index, AASI, and PSR) are associated with increased cardiovascular disease risk, but it remains unclear whether these indicators are useful in improving medical care quality; the standard of care remains stringent BP control.

Aortic Function's Adaptation in Response to Exercise-Induced Stress Assessing by 1.5T MRI: A Pilot Study in Healthy Volunteers

Aim

Evaluation of the aortic “elastic reserve” might be a relevant marker to assess the risk of aortic event. Our aim was to compare regional aortic elasticity at rest and during supine bicycle exercise at 1.5 T MRI in healthy individuals.

Methods

Fifteen volunteers (8 men), with a mean age of 29 (23–41) years, completed the entire protocol. Images were acquired immediately following maximal exercise. Retrospective cine sequences were acquired to assess compliance, distensibility, maximum rates of systolic distension and diastolic recoil at four different locations: ascending aorta, proximal descending aorta, distal descending aorta and aorta above the coeliac trunk level. Segmental aortic pulse wave velocity (PWV) was assessed by through plane velocity-encoded MRI.

Results

Exercise induced a significant decrease of aortic compliance and distensibility, and a significant increase of the absolute values of maximum rates of systolic distension and diastolic recoil at all sites (p<10–3). At rest and during stress, ascending aortic compliance was statistically higher compared to the whole descending aorta (p≤0.0007). We found a strong correlation between the rate pressure product and aortic distensibility at all sites (r = - 0.6 to -0.75 according to the site, p<10–4). PWV measured at the proximal and distal descending aorta increased significantly during stress (p = 0.02 and p = 0.008, respectively).

Conclusion

Assessment of regional aortic function during exercise is feasible using MRI. During stress, aortic elasticity decreases significantly in correlation with an increase of the PWV. Further studies are required to create thresholds for ascending aorta dysfunction among patients with aneurysms, and to monitor the impact of medication on aortic remodeling.

Effect of aliskiren on vascular remodelling in small retinal circulation

BACKGROUND

In hypertension, changes in small arterial structure are characterized by an increased wall-to-lumen ratio (WLR). These adaptive processes are modulated by the rennin-angiotensin system. It is unclear whether direct renin inhibitors exert protective effects on small arteries in hypertensive patients.

METHODS

In this double-blind, randomized, placebo-controlled study (http://www.clinicaltrials.gov: NCT01318395), 114 patients with primary hypertension were randomized to additional therapy with either placebo or aliskiren 300 mg for 8 weeks after 4 weeks of standardized open-label treatment with valsartan 320 mg (run-in phase). Parameter of arteriolar remodelling was WLR of retinal arterioles (80 - 140 μm) assessed noninvasively and in vivo by scanning laser Doppler flowmetry (Heidelberg Engineering, Germany). In addition, pulse wave analysis (SphygmoCor, AtCor Medical, Australia) and pulse pressure (PP) amplification were determined.

RESULTS

In the whole study population, no clear effect of additional therapy with aliskiren on vascular parameters was documented. When analyses were restricted to patients with vascular remodelling, defined by a median of WLR more than 0.3326 (n = 57), WLR was reduced after 8 weeks by the treatment with aliskiren compared with placebo (-0.044 ± 0.07 versus 0.0043 ± 0.07, P = 0.015). Consistently, after 8 weeks of on-top treatment with aliskiren, there was an improvement of PP amplification compared with placebo (0.025 ± 0.07 versus -0.034 ± 0.08, P = 0.013), indicative of less stiff arteries in the peripheral circulation.

CONCLUSION

Thus, our data indicate that treatment with aliskiren, given on top of valsartan therapy, improves altered vascular remodelling in hypertensive patients.

Abnormal Pulsatile Hemodynamics in Hypertensive Patients With Normalized 24-Hour Ambulatory Blood Pressure by Combination Therapy of Three or More Antihypertensive Agents

It remains uncertain whether intensive antihypertensive therapy can normalize pulsatile hemodynamics resulting in minimized residual cardiovascular risks. In this study, office and 24-hour ambulatory systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure, carotid-femoral pulse wave velocity (PWV), and forward (Pf) and reflected (Pb) pressure wave from a decomposed carotid pressure wave were measured in hypertensive participants. Among them, 57 patients whose 24-hour SBP and DBP were normalized by three or more classes of antihypertensive medications were included. Another 57 age- and sex-matched normotensive participants were randomly selected from a community survey. The well-treated hypertensive patients had similar 24-hour SBP, lower DBP, and higher PP values. The treated patients had higher PWV (11.7±0.3 vs 8.3±0.2 m/s, P<.001), Pf, Pb, Pb/Pf, and left ventricular mass index values. After adjustment for age, sex, body mass index, and office SBP, the differences for PWV, Pb, and Pb/Pf remained significant. Hypertensive patients whose 24-hour SBP and DBP are normalized may still have markedly increased arterial stiffness and wave reflection.

"Smooth Muscle Cell Stiffness Syndrome"-Revisiting the Structural Basis of Arterial Stiffness

In recent decades, the pervasiveness of increased arterial stiffness in patients with cardiovascular disease has become increasingly apparent. Though, this phenomenon has been well documented in humans and animal models of disease for well over a century, there has been surprisingly limited development in a deeper mechanistic understanding of arterial stiffness. Much of the historical literature has focused on changes in extracellular matrix proteins—collagen and elastin. However, extracellular matrix changes alone appear insufficient to consistently account for observed changes in vascular stiffness, which we observed in our studies of aortic stiffness in aging monkeys. This led us to examine novel mechanisms operating at the level of the vascular smooth muscle cell (VSMC)—that include increased cell stiffness and adhesion to extracellular matrix—which that may be interrelated with other mechanisms contributing to arterial stiffness. We introduce these observations as a new concept—the Smooth Muscle Cell Stiffness Syndrome (SMCSS)—within the field of arterial stiffness and posit that stiffening of vascular cells impairs vascular function and may contribute stiffening to the vasculature with aging and cardiovascular disease. Importantly, this review article revisits the structural basis of arterial stiffness in light of these novel findings. Such classification of SMCSS and its contextualization into our current understanding of vascular mechanics may be useful in the development of strategic therapeutics to directly target arterial stiffness.

Arterial stiffness is elevated in normotensive type 2 diabetic patients with peripheral neuropathy

BACKGROUND AND AIMS

Arterial stiffness, a measure of macrovascular damage predictive of poor cardio-vascular outcomes, is strongly related to age and hypertension (HT). In diabetic patients peripheral neuropathy (PN) has been found to be associated with increased arterial stiffness, which might be due to the concomitant presence of HT. The aim of this study was to examine in type-2 diabetic patients, the relationship between arterial stiffness and presence or absence of PN and HT separately.

METHODS AND RESULTS

Arterial stiffness was measured with the gold standard carotid-femoral pulse wave velocity (PWV) in 447 type-2 diabetic subjects of whom 66% were hypertensive, 53% had PN, and 40% had both. Patients with PN were older, more often hypertensive and had higher PWV than those free of PN. Patients were separated according to the presence or absence of PN and HT. PWV values above the 90th percentile age- and blood pressure-adjusted reference range (PWV+) were different across these groups (p < 0.005) with the following respective prevalences: 27.2%, 53.4%, 33.3% and 30.6%. Only PWV+ was significantly associated with PN and hypertension in the interaction analysis.

CONCLUSION

Well controlled hypertensive patients did not have elevated arterial stiffness compared to normotensive patients. This might be due to anti-hypertensive treatment although our study design does not allow us to confirm it. A strong association between PN and arterial stiffness was only present in normotensive patients, suggesting that normotensive type 2 diabetic patients with PN and elevated arterial stiffness should be carefully managed to prevent future macrovascular complications.

Olmesartan improves pulse wave velocity and lowers central systolic blood pressure and ambulatory blood pressure in patients with metabolic syndrome

Ambulatory blood pressure (BP) and central systolic BP (cSBP) are superior to brachial office BP measurements in predicting cardiovascular end organ damage. The authors aimed to analyze the effect of olmesartan 80 mg (OLM 80) vs 20 mg (OLM 20) vs amlodipine 5 mg (AML 5) on central hemodymamics and ambulatory BP in patients with metabolic syndrome (MetS).In a double-blind, three-phase crossover study comprising 69 untreated patients with MetS defined by the Third Report of the Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults guidelines, the effects of OLM 80 on central hemodynamics (cSBP), central pulse pressure), pulse wave velocity (PWV), and 24-hour ambulatory BP were compared with OLM 20 and AML 5, given for 6 weeks each. In 69 patients (47 men, 22 women) (51.5±9.75 years), reduction in cSBP was the highest with OLM 80 and significantly greater than the reduction with AML 5 (-14.1 mm Hg vs -9.7 mm Hg, P=.0117). All three substances significantly reduced 24-hour ambulatory systolic (OLM 80 and OLM 20 P<.0001; AML 5 P=.0105). BP and 24-hour diastolic BP (OLM 80 and OLM 20 P<.0001; AML 5 P=.0126). PWV was significantly reduced by OLM 80 (-0.58 m/s, P=.0088) and by OLM 20 (-0.48 m/s, P=.0362) but not by AML 5 (-0.28 m/s, P=.2065). For PWV, no significant differences were detected between the three groups. OLM significantly improves arterial stiffness as demonstrated by the reduction in PWV and in cSBP. In addition, 24-hour ambulatory BP was reduced to a greater extent with OLM 80 than with AML 5.