Relation of elevated plasma renin activity at baseline to cardiac events in patients with angiographically proven coronary artery disease

Validation of an Integrated Genetic-Epigenetic Test for the Assessment of Coronary Heart Disease

BACKGROUND

Coronary heart disease (CHD) is the leading cause of death in the world. Unfortunately, many of the key diagnostic tools for CHD are insensitive, invasive, and costly; require significant specialized infrastructure investments; and do not provide information to guide postdiagnosis therapy. In prior work using data from the Framingham Heart Study, we provided in silico evidence that integrated genetic-epigenetic tools may provide a new avenue for assessing CHD.

METHODS AND RESULTS

In this communication, we use an improved machine learning approach and data from 2 additional cohorts, totaling 449 cases and 2067 controls, to develop a better model for ascertaining symptomatic CHD. Using the DNA from the 2 new cohorts, we translate and validate the in silico findings into an artificial intelligence-guided, clinically implementable method that uses input from 6 methylation-sensitive digital polymerase chain reaction and 10 genotyping assays. Using this method, the overall average area under the curve, sensitivity, and specificity in the 3 test cohorts is 82%, 79%, and 76%, respectively. Analysis of targeted cytosine-phospho-guanine loci shows that they map to key risk pathways involved in atherosclerosis that suggest specific therapeutic approaches.

CONCLUSIONS

We conclude that this scalable integrated genetic-epigenetic approach is useful for the diagnosis of symptomatic CHD, performs favorably as compared with many existing methods, and may provide personalized insight to CHD therapy. Furthermore, given the dynamic nature of DNA methylation and the ease of methylation-sensitive digital polymerase chain reaction methodologies, these findings may pave a pathway for precision epigenetic approaches for monitoring CHD treatment response.

Multimarkers of metabolic malnutrition and inflammation and their association with mortality risk in cardiac catheterisation patients: a prospective, longitudinal, observational, cohort study

BACKGROUND

Complex and incompletely understood metabolic dysfunction associated with inflammation and protein-energy wasting contribute to the increased mortality risk of older patients and those with chronic organ diseases affected by cachexia, sarcopenia, malnutrition, and frailty. However, these wasting syndromes have uncertain relevance for patients with cardiovascular disease or people at lower risk. Studies are hampered by imperfect objective clinical assessment tools for these intertwined metabolic malnutrition and inflammation syndromes. We aimed to assess, in two independent cohorts of patients who underwent cardiac catheterisation, the mortality risk associated with the metabolic vulnerability index (MVX), a multimarker derived from six simultaneously measured serum biomarkers plausibly linked to these dysmetabolic syndromes.

METHODS

In this prospective, longitudinal, observational study, we included patients aged ≥18 years recruited into the CATHGEN biorepository (Jan 2, 2001, to Dec 30, 2011) and the Intermountain Heart Collaborative Study (Sept 12, 2000, to Sept 21, 2006) who underwent coronary angiography and had clinical nuclear magnetic resonance metabolomic profiling done on frozen plasma obtained at catheterisation. We aggregated six mortality risk biomarkers (GlycA, small HDL, valine, leucine, isoleucine, and citrate concentrations) into sex-specific MVX multimarker scores using coefficients from predictive models for all-cause mortality in the CATHGEN cohort. We assessed associations of biomarkers and MVX with mortality in both cohorts using Cox proportional hazards models adjusted for 15 clinical covariates.

FINDINGS

We included 5876 participants from the CATHGEN biorepository and 2888 from the Intermountain Heart study. Median follow-up was 6·2 years (IQR 4·4-8·9) in CATHGEN and 8·2 years (6·9-9·2) in the Intermountain Heart study. The six nuclear magnetic resonance biomarkers and MVX made strong, independent contributions to 5-year mortality risk prediction in both cohorts (hazard ratio 2·18 [95% CI 2·03-2·34] in the CATHGEN cohort and 1·67 [1·50-1·87] in the Intermountain Heart cohort). CATHGEN subgroup analyses showed similar MVX associations in men and women, older and younger individuals, for death from cardiovascular or non-cardiovascular causes, and in patients with or without multiple comorbidities.

INTERPRETATION

MVX made a dominant contribution to mortality prediction in patients with cardiovascular disease and in low-risk subgroups without pre-existing disease, suggesting that metabolic malnutrition-inflammation syndromes might have a more universal role in survival than previously thought.

FUNDING

Labcorp.

Higher plasma renin activity is associated with increased kidney damage risk in patients with hypertension and glucose metabolic disorders

The impact of renin on kidney remain unclear among hypertensives with glucose metabolic disorders (GMD). We aimed to evaluate the association between plasma renin activity (PRA) and kidney damage in hypertensive patients with GMD. Overall, 2033 inpatients with hypertension and GMD free of chronic kidney disease (CKD) at baseline were included. CKD was defined using estimated glomerular filtration rate (eGFR) and urine protein. PRA was treated as continuous variable, and also dichotomized as high (≥0.65) or low (< 0.65) groups. The association of PRA with incident CKD was evaluated using multivariable Cox model controlling for antihypertensive medications and baseline aldosterone, and traditional parameters. Subgroup and interaction analyses were performed to evaluate heterogeneity. During a median follow‐up of 31 months, 291 participants developed CKD. The incidence was higher in high‐renin group than that in low‐renin group (54.6 vs 36.6/1000 person‐years). Significant association was observed between PRA and incident CKD, and the association was mainly driven by an increased risk for proteinuria. Each standard deviation increment in log‐transformed PRA was associated with 16.7% increased risk of proteinuria (hazard ratio = 1.167, P = .03); compared with low‐renin group, there was 78.4% increased risk for high‐renin group (hazard ratio = 1.784, P = .001). Nonlinear associations were observed between PRA and kidney damage. Higher PRA is associated with greater risk of incident kidney damage, especially for positive proteinuria, in patients with coexistence of hypertension and diabetes, independent of aldosterone. In this patient population with high risk for kidney damage, PRA may serve as an important predictor.

External validation of integrated genetic-epigenetic biomarkers for predicting incident coronary heart disease

Aim: The Framingham Risk Score (FRS) and atherosclerotic cardiovascular disease (ASCVD) Pooled Cohort Equation (PCE) for predicting risk for incident coronary heart disease (CHD) work poorly. To improve risk stratification for CHD, we developed a novel integrated genetic-epigenetic tool. Materials & methods: Using machine learning techniques and datasets from the Framingham Heart Study (FHS) and Intermountain Healthcare (IM), we developed and validated an integrated genetic-epigenetic model for predicting 3-year incident CHD. Results: Our approach was more sensitive than FRS and PCE and had high generalizability across cohorts. It performed with sensitivity/specificity of 79/75% in the FHS test set and 75/72% in the IM set. The sensitivity/specificity was 15/93% in FHS and 31/89% in IM for FRS, and sensitivity/specificity was 41/74% in FHS and 69/55% in IM for PCE. Conclusion: The use of our tool in a clinical setting could better identify patients at high risk for a heart attack.

Plasma renin activity has a complex prognostic role in patients with acute coronary syndromes

BACKGROUND

Plasma renin activity (PRA) has been related to all-cause mortality and cardiovascular events in patients with cardiovascular disease. However, data from patients with acute coronary syndromes (ACS) are sparse.

METHODS

Determination of PRA was made in 550 patients with ACS, including a subgroup of 287 patients not on treatment with angiotensin converting enzyme inhibitors, angiotensin receptor blockers or diuretics, and without heart failure. We evaluated the relations between PRA and all-cause mortality after three years and long-term, and to cardiovascular events after median 8.7 years. Adjustments were made for variables that influenced the hazard ratio (HR) > 5% for the relation between PRA and outcome.

RESULTS

Baseline PRA was associated with all-cause mortality during three-years (unadjusted HR 1.74 per 1 SD increase in logarithmically transformed PRA; 95% confidence interval (CI) 1.39-2.16, p < 0.0001) and long-term (HR 1.12, CI 1.00-1.25, p = 0.046). After adjustments, only the three-year association remained significant. In unadjusted analyses, PRA was associated with cardiovascular death, but not with nonfatal cardiovascular events. In the subgroup there was an inverse relation between PRA and long-term all-cause mortality.

CONCLUSION

Higher PRA was a significant independent predictor of all-cause mortality after three years, but not at long-term follow-up and not significantly associated with cardiovascular incidence. The renin-angiotensin-system pathophysiology is of great interest, not least due to its association with the COVID-19 pandemic. Our findings indicate a need for further research on the prognostic/predictive aspects of the renin-angiotensin-system in ACS.

GlycA and hsCRP are independent and additive predictors of future cardiovascular events among patients undergoing angiography: The intermountain heart collaborative study

BACKGROUND

GlycA is an inflammatory marker that is raised in patients with cardiometabolic diseases and associated with cardiovascular (CV) events. We sought to determine if GlycA adds independent value to hsCRP for CV risk prediction.

METHODS

Patients in the Intermountain Heart Collaborative Study who underwent coronary angiography and had plasma GlycA and hsCRP levels were studied (n = 2996). Patients were followed for 7.0 ± 2.8 years. GlycA and hsCRP were moderately correlated (r = 0.46, P < .0001). GlycA and hsCRP concentrations were stratified into high and low categories by their median values. Multivariable cox hazard regression was utilized to determine the associations of GlycA quartiles, as well as high and low categories of GlycA and hsCRP, with major adverse cardiovascular events (MACE) defined as the composite of death, myocardial infarction (MI), heart failure (HF) hospitalization, and stroke.

RESULTS

The highest GlycA quartile was associated with future MACE [HR: 1.43; 95% CI: 1.22-1.69; P < .0001]. Patients with high GlycA and high hsCRP had more diabetes, hyperlipidemia, hypertension, HF, renal failure and MI, but not coronary artery disease. High GlycA and hsCRP (H/H) versus low GlycA and hsCRP (L/L) was associated with MACE, death and HF hospitalization, but not MI or stroke. Combined MACE rates were 33.5%, 41.3%, 35.7% and 49.1% for L/L, L/H, H/L and H/H categories of GlycA/hsCRP, respectively (P-trend < .0001). The interaction between GlycA and hsCRP was significant for the outcome of death (P = .03).

CONCLUSION

In this study, levels of GlycA and hsCRP were independent and additive markers of risk for MACE, death and HF hospitalization.

Renin and aldosterone are not associated with vulnerable plaque characteristics in patients with carotid artery disease

BACKGROUND

The renin-angiotensin-aldosterone system is increasingly being recognized to play an important role in the development and clinical course of cardiovascular diseases. Renin-angiotensin-aldosterone system activation is associated with clinical outcome in various populations of cardiovascular patients, such as patients with coronary artery, peripheral artery, and cerebrovascular disease. In this study, we investigated the associations between plasma renin and aldosterone concentrations and atherosclerotic plaque characteristics and secondary vascular events in patients undergoing carotid endarterectomy.

METHODS AND RESULTS

Baseline plasma renin and aldosterone concentrations from 506 subjects undergoing carotid endarterectomy (mean age, 67 ± 9 years; 65% male) were correlated with histopathologic characteristics and inflammatory protein concentrations of the excised atherosclerotic plaque. Ordinal logistic regression (for ordinal outcome parameters) or linear regression (for linear outcome) analysis did not show a statistically significant relationship between plasma renin or aldosterone concentrations and plaque fat, thrombus, calcifications, collagen, smooth muscle cells, or macrophage content. Neither could any association be found with intraplaque inflammatory mediators. During a median follow-up of 3 years, 102 (20%) patients experienced a major secondary vascular event (composite of stroke, myocardial infarction, leg amputation, vascular death, or coronary revascularization or peripheral intervention). In multivariable Cox regression analysis, including both renin and aldosterone, baseline renin concentrations were associated with the occurrence of secondary events.

CONCLUSIONS

In patients with established atherosclerotic disease undergoing carotid endarterectomy, plasma renin and aldosterone concentrations were not associated with atherosclerotic plaque characteristics. Plasma renin concentration was positively associated with the occurrence of major secondary vascular events.

Excessively low salt diet damages the heart through activation of cardiac (pro) renin receptor, renin-angiotensin-aldosterone, and sympatho-adrenal systems in spontaneously hypertensive rats

OBJECTIVE

A high salt intake causes hypertension and leads to cardiovascular disease. Therefore, a low salt diet is now recommended to prevent hypertension and cardiovascular disease. However, it is still unknown whether an excessively low salt diet is beneficial or harmful for the heart.

METHODS

Wistar Kyoto rats (WKYs) and spontaneously hypertensive rats (SHRs) received normal salt chow (0.9% salt diet) and excessively low salt chow (0.01% salt diet referred to as saltless diet) for 8 weeks from 8 to 16 weeks of age. The effects of the excessively low salt diet on the cardiac (pro) renin receptor, renin-angiotensin-aldosterone, and sympatho-adrenal systems were investigated.

RESULTS

The excessively low salt diet did not affect the systolic blood pressure but significantly increased the heart rate both in WKYs and SHRs. The excessively low salt diet significantly elevated plasma renin activity, plasma angiotensin I, II and aldosterone concentrations, and plasma noradrenaline and adrenaline concentrations both in WKYs and SHRs. Cardiac expressions of renin, prorenin, (P)RR, angiotensinogen, and angiotensin II AT1 receptor and phosphorylated (p)-ERK1/2, p-HSP27, p-38MAPK, and TGF-ß1 were significantly enhanced by the excessively low salt diet in both WKYs and SHRs. The excessively low salt diet accelerated cardiac interstitial and perivascular fibrosis and increased the cardiomyocyte size and interventricular septum thickness in WKYs and SHRs but the extent was greater in SHRs.

CONCLUSION

An excessively low salt diet damages the heart through activation of plasma renin-angiotensin-aldosterone and sympatho-adrenal systems and activation of cardiac (P)RR and angiotensin II AT1 receptor and their downstream signals both in WKYs and SHRs.

Utility of high density lipoprotein particle concentration in predicting future major adverse cardiovascular events among patients undergoing angiography

BACKGROUND

HDL-C is recognized to be inversely associated with cardiovascular (CV) risk. However, attenuation of the association of HDL-C with CV risk may occur after adjustment for other lipoprotein parameters and in various disease states, especially in the setting of acute coronary syndrome (ACS). Recently, the number of HDL particles (HDL-P) has been suggested to improve CV risk prediction.

METHODS AND RESULTS

Patients (n=2999) in the Intermountain Heart Collaborative Study who underwent angiography and had lipoprotein particle measurements determined by nuclear magnetic resonance (NMR) spectroscopy were studied. Multivariable Cox hazard regression was utilized to evaluate the association of HDL-C, HDL-P, and HDL-P subclasses with future major adverse CV events (MACE: death, myocardial infarction, heart failure, and stroke). Patients averaged 64±12years, 66% male, 26% diabetic, and 42% ACS. At angiography, 65% of patients were diagnosed with coronary artery disease (CAD). HDL-C and HDL-P averaged 41±13mg/dL and 28±8μmol/L, respectively. HDL-P (HR=0.903, p=0.001), but not HDL-C (HR=0.947, p=0.102) was significantly associated with MACE. In a model that included all HDL-P subclasses, both small (HR=0.862, p<0.0001) and medium (HR=0.922, p=0.020) were associated with CV risk, but not large HDL-P (HR=1.0042, p=0.185). Small HDL-P continued to be associated with all of the individual components of MACE, but not stroke.

CONCLUSION

In this study of patients undergoing angiography, HDL-P was a strong, independent predictor of future MACE, with the smaller HDL-P accounting for this association.

Plasma renin activity and risk of cardiovascular and mortality outcomes among individuals with elevated and nonelevated blood pressure

Background

We sought to evaluate plasma renin activity (PRA) levels and risk of mortality and cardiovascular events among individuals with elevated blood pressure [systolic blood pressure (SBP) ≥ 140 mmHg] and those with controlled blood pressure (SBP < 140 mmHg) in a large diverse population.

Methods

A retrospective cohort study between January 1, 2007, and December 31, 2013, among adults (≥ 18 years) within an integrated health system was conducted. Subjects were categorized by SBP into 2 groups: SBP < 140 mmHg and SBP ≥ 140 mmHg and then further categorized into population-based PRA tertiles within each SBP group. Cox proportional hazard modeling was used to estimate hazard ratios for cardiovascular and mortality outcomes among tertiles of PRA levels.

Results

Among 6,331 subjects, 32.6% had SBP ≥ 140 mmHg. Multivariable hazard ratios and 95% confidence interval for PRA tertiles T2 and T3 compared to T1 in subjects with SBP ≥ 140 mmHg were 1.42 (0.99–2.03) and 1.61 (1.12–2.33) for ischemic heart events; 1.40 (0.93–2.10) and 2.23 (1.53–3.27) for congestive heart failure; 1.10 (0.73–1.68) and 1.06 (0.68–1.66) for cerebrovascular accident; 1.23 (0.94–1.59) and 1.43 (1.10–1.86) for combined cardiovascular events; and 1.39 (0.97–1.99) and 1.35 (0.92–1.97) for all-cause mortality, respectively. Among the SBP < 140 mmHg group, there was no relationship between PRA levels and outcomes.

Conclusion

Higher PRA levels demonstrated increased risk for ischemic heart events and congestive heart failure and a trend toward higher mortality among individuals with SBP ≥ 140 mmHg but not among those with SBP < 140 mmHg.

Brain natriuretic peptide as a potential novel marker of salt-sensitivity in chronic kidney disease patients without cardiac dysfunction

Although the renin-angiotensin system (RAS) is counter-balanced by a salt-sensitive mechanism in the hypertensive state, both are reported to be up-regulated in chronic kidney disease (CKD) patients. We conducted this study to evaluate the associations among the RAS, renal function, hypertension, and atherosclerosis, as well as to identify markers for salt-sensitivity. A total of 213 pre-dialysis CKD patients with preserved cardiac function (EF >50 %) were enrolled. Their renal and cardiac biochemical markers and plasma renin activity (PRA) were measured, and echocardiography and carotid artery ultrasound were performed. Their salt intake was estimated by the NaCl excretion from a 24-h collected urine sample. The PRA was higher in patients with hypertension (p = 0.018), and had a significant negative correlation with the eGFR (r = -0.23, p = 0.0067). Importantly, the PRA had a strong negative correlation with the brain natriuretic peptide (BNP) level (r = -0.28, p = 0.017) regardless of whether the patients were being treated with RAS inhibitors. The BNP level was related to the renal functions (eGFR: p = 0.001, ACR: p = 0.009). There was a significant positive correlation between the BNP level and carotid intima-media thickness (p < 0.001). A multivariate analysis revealed that older age and an excess of NaCl excretion were independent predictors of BNP elevation (p = 0.02 and 0.003, respectively). Our analysis revealed details of the counterbalance between BNP and PRA, as well as identifying that excess salt intake is a predictor of BNP elevation. These results indicate that the BNP could be a possible valuable marker for salt sensitivity, and that high salt sensitivity could facilitate atherosclerosis in CKD patients.

Higher plasma prorenin concentration plays a role in the development of coronary artery disease

BACKGROUND

Prorenin and renin are both involved in atherosclerosis. However, the role of plasma prorenin and renin in the development and progression of coronary artery disease (CAD) is still not clear. Thus, we aimed to examine the relationships among plasma prorenin concentration, CAD and clinical parameters.

METHODS

We measured plasma prorenin and renin concentrations and other parameters in 85 patients who underwent coronary angiography. Patients were divided into a CAD group (≥75 % stenosis in one or more coronary arteries) and a non-CAD group.

RESULTS

There was a weak correlation between prorenin and plasma renin concentration (r =0.35, p =0.001), and plasma renin activity (r =0.34, p =0.001). There was no significant difference in the plasma prorenin concentration between the CAD group and non-CAD group. However, patients with a high plasma prorenin concentration frequently suffered CAD. Receiver-operating-characteristic curve analysis showed that the optimal cutoff value of plasma prorenin concentration to detect CAD was 1,100 pg/ml, with a positive predictive value of 94 % and a negative predictive value of 36 %.

CONCLUSION

The plasma prorenin concentration increases with increases in plasma renin concentration. Higher plasma prorenin concentration (>1,100 pg/ml) plays a role in the development of CAD.

Combination therapy in chronic kidney disease?

The renin-angiotensin system (RAS) plays a fundamental role in preserving the circulation and yet, it may be injurious to heart and blood vessels and may also allow, and sometimes hasten, kidney disease progression. Thus, effective RAS inhibition may be a major pharmacologic necessity to control hypertension, to decrease cardiovascular complication, and to inhibit kidney disease progression. Unfortunately, the beneficial effects attained in the management of renal disease sometimes are incomplete. The reasons for these inadequate outcomes may include angiotensin escape or excessive local angiotensin production. Two pharmacologic strategies have been proposed to overcome this drawback including higher than recommended doses of RAS inhibitors and the combination of two different RAS inhibitors. However, three large studies have shown that these more intensive pharmacologic approaches should be treated with caution when applied to high-risk patients, as organ perfusion may fall to critical levels that may cause severe complications. Nevertheless, intensive RAS inhibition (including combination therapy) may be the sole alternative in patients with chronic kidney disease (CKD) in whom other therapeutics options have failed. In these cases, adequate precautions including close clinical and laboratory follow up should prevent major complications.

Plasma renin activity and its association with ischemic heart disease, congestive heart failure, and cerebrovascular disease in a large hypertensive cohort

Plasma renin activity (PRA) may be a surrogate for vascular damage. The authors hypothesize that PRA is associated with cardiovascular and cerebrovascular disease (CED). A cross-sectional study (January 1, 1998, to December 31, 2009) was performed on hypertensive individuals 18 years and older using multivariable logistic regression models to estimate odds ratios (ORs) for ischemic heart disease (IHD), congestive heart failure (CHF), and CED based on PRA quartiles controlling for age, sex, race, diabetes mellitus (DM), and medication use. Among 7887 individuals (60% women; 34% whites, 23% blacks, and 19% Hispanics; and 29% with DM), the adjusted ORs (95% CI) for IHD were 0.94 (0.80-1.10), 1.09 (0.92-1.29), and 1.18 (1.00-1.39); for CHF were 1.23 (0.99-1.53), 1.27 (1.01-1.61), and 1.41 (1.13-1.77); and for CED were 0.95 (0.78-1.17), 0.77 (0.61-0.97), and 0.97 (0.78-1.20) for the second, third, and fourth quartiles compared with the first quartile. Higher PRA was associated with greater likelihood for prevalent IHD and CHF but not CED in this large ethnically diverse population of hypertensive individuals.

Association of renin and aldosterone with ethnicity and blood pressure: the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Although variations in plasma renin activity (PRA) and aldosterone have been examined in whites and blacks, the association of these hormones with blood pressure in multiethnic populations has not been described.

METHODS

We measured PRA and aldosterone in 1,021 participants in the Multi-Ethnic Study of Atherosclerosis not taking antihypertensives and examined the association between ethnicity and PRA/aldosterone and the association between PRA/aldosterone with systolic blood pressure (SBP).

RESULTS

Average age was 62 (SD = 9) years, and 49% of participants were women. Median PRA was 0.51 (interquartile range (IQR) = 0.29-0.87) ng/ml/hour, and median aldosterone was 12.6 (IQR = 9.1-17.1) ng/dl. After age and sex adjustment, compared with whites, blacks had 28% lower PRA and 17.4% lower aldosterone, and Hispanics had 20.1% higher PRA but similar aldosterone levels. After multivariable adjustment, compared with whites, only Hispanic ethnicity independently associated with higher PRA (0.18ng/ml/hour; 95% confidence interval (CI) = 0.06-0.31). Blacks had lower aldosterone (-1.7ng/dl; 95% CI = -3.2 to -0.2) compared with whites. After multivariable adjustment, PRA was associated with lower SBP in whites (-3.2mm Hg; 95% CI = -5.2 to -1.2 per standardized unit PRA), Chinese (-3.5mm Hg; 95% CI = -6.2 to -0.80 per standardized unit), and Hispanics (-2.3mm Hg; 95% CI = -4.1 to -0.6 per standardized unit) but not blacks. Aldosterone was associated with higher SBP only in Hispanics (2.5mm Hg; 95% CI = 0.4-4.5 per SD).

CONCLUSIONS

Compared with whites, blacks have lower aldosterone and Hispanics have higher PRA. Aldosterone had significant associations with higher SBP in Hispanics compared with other groups, a finding that may suggest a different mechanism of hypertension.

Relationship of renin-angiotensin-aldosterone system polymorphisms and phenotypes to mortality in Chinese coronary atherosclerosis patients

We performed a large, long-term cohort study to evaluate the association of renin-angiotensin-aldosterone system gene polymorphisms and baseline phenotypes to all-cause mortality among patients with angiographically confirmed coronary atherosclerosis. The study included 1075 subjects who underwent coronary angiography. Patients were genotyped for eight polymorphisms (rs4343, rs5186, rs5182, rs5049, rs5051, rs699, rs4762, and rs1799998), and their baseline plasma angiotensin II and aldosterone levels were measured. The interval between baseline and follow-up time-points ranged from 6.39 to 9.59 years. The results of multivariate regression analysis further indicated that high baseline angiotensin II levels (1.226 (1.024–1.468), p = 0.027) were independently associated with all-cause death. Therefore, we found that an increased baseline plasma angiotensin II level was associated with higher long-term all-cause mortality, even after correcting for established cardiovascular risk factors.

Renin-angiotensin system blockers may create more risk than reward for sodium-depleted cardiovascular patients with high plasma renin levels

BACKGROUND

Four recent reports revealed differences in survival rates among treated cardiovascular patients taking renin-angiotensin system-blocking drugs. Patients with higher on-treatment plasma renin activity (PRA) levels died sooner of cardiovascular mortality than those with lower levels. We investigated whether excessive sodium depletion might have induced the higher PRA levels and contributed to the greater morbidity and mortality.

METHODS

Using published data, ranges of PRA, blood pressures, drug usage, and biochemical parameters were compared among various groups of cardiovascular patients.

RESULTS

We showed (i) that PRA levels are usually medium to low in treated cardiovascular patients, but are sometimes abnormally high, (ii) that excessive sodium depletion can induce such high PRA levels, (iii) that the higher PRA patients exhibited evidence of sodium depletion: lower blood pressures, more frequent natriuretic drug usage, lower N-terminal pro b-type natriuretic peptide (NT-proBNP), and higher blood urea nitrogen and uric acid levels, with similar usage of renin-angiotensin blocking drugs.

CONCLUSIONS

We hypothesize that patients with high on-treatment PRA levels die sooner of cardiovascular events because they are excessively sodium-volume depleted. Moreover, renin-angiotensin system-blocking drugs may be harmful in such patients because they can functionally interfere with the effects of reactive rises in PRA that are triggered to prevent potentially dangerous falls in blood pressure, increases in plasma potassium, and falls in glomerular filtration rate. Careful liberalization of salt intake and subtraction of natriuretic drugs, sufficient to reduce reactive hyperreninemia without inducing unacceptable increases in blood pressure, might benefit such patients and decrease risk of adverse effects from drugs that block the renin-angiotensin system.

New roles for renin and prorenin in heart failure and cardiorenal crosstalk

The renin-angiotensin-aldosterone-system (RAAS) plays a central role in the pathophysiology of heart failure and cardiorenal interaction. Drugs interfering in the RAAS form the pillars in treatment of heart failure and cardiorenal syndrome. Although RAAS inhibitors improve prognosis, heart failure–associated morbidity and mortality remain high, especially in the presence of kidney disease. The effect of RAAS blockade may be limited due to the loss of an inhibitory feedback of angiotensin II on renin production. The subsequent increase in prorenin and renin may activate several alternative pathways. These include the recently discovered (pro-) renin receptor, angiotensin II escape via chymase and cathepsin, and the formation of various angiotensin subforms upstream from the blockade, including angiotensin 1–7, angiotensin III, and angiotensin IV. Recently, the direct renin inhibitor aliskiren has been proven effective in reducing plasma renin activity (PRA) and appears to provide additional (tissue) RAAS blockade on top of angiotensin-converting enzyme and angiotensin receptor blockers, underscoring the important role of renin, even (or more so) under adequate RAAS blockade. Reducing PRA however occurs at the expense of an increase plasma renin concentration (PRC). PRC may exert direct effects independent of PRA through the recently discovered (pro-) renin receptor. Additional novel possibilities to interfere in the RAAS, for instance using vitamin D receptor activation, as well as the increased knowledge on alternative pathways, have revived the question on how ideal RAAS-guided therapy should be implemented. Renin and prorenin are pivotal since these are at the base of all of these pathways.

Direct renin inhibition: extricating facts from façades

The renin–angiotensin system (RAS) affects vascular tone, cardiac output and kidney function. By these means the RAS plays a key role in the pathogenesis of arterial hypertension. As a result, RAS inhibition is highly effective not only in lowering blood pressure but also in reducing kidney disease progression (particularly when associated with proteinuria) and cardiovascular events.

Among RAS blocking agents, direct renin inhibitors have shown not only excellent efficacy in hypertension control but also pharmacologic tolerance that is comparable with other renin–angiotensin suppressors. Indeed, aliskiren, the only direct renin inhibitor available is effective in controlling blood pressure as monotherapy or in combination with other antihypertensive drugs, irrespective of patient’s age, ethnicity or sex. It is also effective in patients with metabolic syndrome, obesity and diabetes. Long-term studies comparing ‘hard endpoints’ of aliskiren therapy versus treatment with other RAS inhibitors, including cardiac and kidney protection, are currently ongoing. Combined with other antihypertensive agents, aliskiren not only improves their hypotensive response but may also lessen the adverse effects of other drugs. In high-risk patients, however, precautions should be taken when combining two or more renin–angiotensin inhibiting agents, as tissue perfusion may be highly renin-dependent in these patients and serious adverse side effects could take place.

Renin and prorenin as biomarkers in hypertension

PURPOSE OF REVIEW

This review examines the evidence that plasma renin and/or prorenin level may be used to guide therapy in hypertension and as an independent risk factor for future cardiovascular events.

RECENT FINDINGS

A large number of retrospective analyses of patient populations in clinical trials, in whom 'baseline' renin measurements were available, supports that high renin, but not high prorenin levels, are indicative of future cardiovascular disease and death, particularly in patients with kidney dysfunction and/or hypertension. The relationship is not affected by the use of renin-angiotensin system (RAS) blockers. High renin levels also tend to support the use of RAS inhibitors as first-choice antihypertensive agents. However, the added value of a renin measurement on top of traditional risk factors is modest, and the pressure response to RAS blockade, even in high-renin patients, varies widely.

SUMMARY

Measuring 'baseline' renin as a marker of future cardiovascular events or to determine the choice of drug is of limited value in an individual patient.

Safety and efficacy of aliskiren in the treatment of hypertension: a systematic overview

INTRODUCTION

Aliskiren is the first orally active direct renin inhibitor approved for the treatment of hypertension. Aliskiren's inhibitory effect on angiotensin I generation, through renin blockade, is highly specific and long-lasting (24 hours). This feature differentiates aliskiren from traditional antihypertensive drugs.

AREAS COVERED

This paper reviews the results of various clinical trials which investigate the safety and efficacy of aliskiren on blood pressure (BP) reduction and clinical end points.

EXPERT OPINION

Aliskiren is suitable for once-daily administration. Its antihypertensive effect is comparable or superior to that of other antihypertensive agents at recommended doses. The tolerability profile of aliskiren is placebo-like at the licensed doses of 150 and 300 mg. In particular, the discontinuation of therapy due to clinical adverse events occurs similarly among patients treated with either aliskiren or placebo. Aliskiren is not recommended in association with ACE-inhibitors or angiotensin II receptor blockers in patients with type 2 diabetes and renal impairment. Pending disclosure of full results, the early termination of the ALTITUDE seems to confirm previous concerns about the safety of the dual pharmacological blockade of the renin-angiotensin system in these patients. Aliskiren is a well-tolerated antihypertensive drug that may help to achieve the recommended targets of BP control.

Blood pressure and plasma renin activity responses to different strategies to inhibit the renin-angiotensin-aldosterone system during exercise

OBJECTIVE

The effect of two different strategies for renin-angiotensin-aldosterone system (RAAS) blockade; direct renin inhibition (DRI) versus angiotensin receptor blockade (ARB) on blood pressure (BP) and plasma renin activity (PRA) was compared during exercise.

METHODS

Hypertensive adults were randomised to aliskiren (300 mg once daily, n=33) or valsartan (320 mg once daily, n=35). BP and PRA were measured during treadmill exercise (Bruce protocol), at baseline, end of treatment (eight weeks), and after treatment withdrawal (48 hours after last dose).

RESULTS

After eight weeks treatment, Aliskiren inhibited PRA (>80%) at rest and during exercise, with inhibition remaining undiminished 48 hours after treatment withdrawal. In contrast, valsartan increased PRA at rest, and more-so during exercise (>400%). Angiotensin receptor blockade, as indicated by PRA increase, was reduced, 48 hours after valsartan treatment withdrawal, suggesting more sustained RAAS blockade with aliskiren. Despite divergent effects on PRA, similar exercise-induced changes in BP were seen. The primary outcome, the rise in systolic BP from rest to peak exercise (baseline to after treatment withdrawal) did not differ between treatments (p=0.25).

CONCLUSION

Measurement of PRA is a more sensitive index of RAAS blockade than the BP response during exercise. Furthermore, after treatment withdrawal, aliskiren provides more sustained RAAS inhibition than valsartan at rest and during exercise.

Failure to intensify hypertension therapy after rejected aliskiren claims

BACKGROUND

Failure to intensify therapy when indicated is a serious problem in the management of hypertension. Patients having an antihypertensive prescription rejected because of utilization management tools may be at a high risk of failing to intensify their therapy when it is warranted.

OBJECTIVE

The goal of this study was to investigate the patterns of therapy change after rejected aliskiren claims because of utilization management tools such as prior authorization, step therapy, and restrictive formulary.

METHODS

A retrospective study was conducted using data from a large national pharmacy benefits manager. Patients with a rejected aliskiren claim because of utilization management and who were naive to aliskiren treatment before having a rejected aliskiren claim were included. Patients were followed up for 6 months after the initial rejected aliskiren claim to see whether there was a therapy change. Therapy change was defined as titration of old regimens, fulfillment of aliskiren, or fulfillment of a new antihypertensive medication not used previously.

RESULTS

A total of 1955 patients were identified (mean age, 64.5 years; 54.4% female). Six months after having rejected aliskiren claims, 36.8% overcame the utilization management and filled aliskiren; 45.1% filled a new antihypertensive medication not used previously; and 10.8% patients titrated old antihypertensive medications. More than one quarter of patients (28.4%) had no change in their antihypertensive treatment. Logistic regression analysis revealed that patients rejected because of prior authorization (odds ratio = 4.00 [95% CI, 1.89-8.44]) or step therapy (odds ratio = 2.59 [95% CI, 1.26-5.32]) were more likely to have a therapy change compared with patients rejected because of a restrictive formulary.

CONCLUSIONS

A significant number of patients had no therapy change 6 months after having rejected aliskiren claims because of utilization management tools, indicating potential clinical inertia or lack of therapy intensification in hypertension management. Patients with restrictive formularies were least likely to have a therapy change. More aggressive follow-up with patients with a rejected claim may be warranted to reduce treatment gaps.

Renin as a biomarker of cardiovascular disease in clinical practice

The search for novel circulating blood biomarkers as predictors of cardiovascular (CV) risk and prognosis is a continuing field of interest in clinical medicine. Biomarkers from several pathophysiological pathways, including markers of organ damage, of inflammation, of the atherosclerotic process and of the coagulation pathway, have been investigated in the last decades. A particular interest has been raised for neurohormonal factors. The role of the activation of the sympathetic system and the renin-angiotensin-aldosterone system (RAAS) in the development of CV diseases has been extensively explored. Renin is the first limiting step of the RAAS and its role as a biomarker to improve CV risk stratification still remains a topic of debate. Several studies have shown that elevated plasma renin activity is associated with increased morbidity and mortality in patients with CV disease. The aim of this paper is to critically evaluate the evidence on the role of renin as a biomarker of CV risk and prognosis. With the new advances of pharmacological treatment acting on the RAAS, the effect of elevated levels of renin on the prognosis of these patients becomes even more intriguing.

Aliskiren for the treatment of essential hypertension under real-life practice conditions: design and baseline data of the prospective 3A registry

BACKGROUND

The renin-angiotensin system (RAS) is a key target for blood pressure control and for cardiovascular and renal protection. Aliskiren is the first-in-class direct oral inhibitor of renin that controls the rate-limiting step in the RAS cascade. So far little is known about the use and efficacy of aliskiren in the treatment of essential hypertension under clinical practice conditions.

METHODS

The 3A registry was an open, prospective cohort study (observational registry) of 14,988 patients in 899 offices throughout Germany. Consecutive patients were eligible for inclusion if their physician had decided to modify their antihypertensive therapy. This included treatment with aliskiren or an angiotensin converting enzyme inhibitor (ACE-I)/angiotensin receptor blocker (ARB) or agents not blocking the RAS, alone or on top of an existing drug regimen.

RESULTS

Mean age of patients was 65 years, their mean body mass index was 28.2 kg/m(2) 53.5% were men, 36% working, 90% in statutory health insurance and 26% in any disease management programme. Patients in the aliskiren and the RAS groups compared with the non-RAS group were older, more often men, had a longer history of hypertension, and had a higher prevalence of comorbidities (diabetes, chronic heart failure, ischaemic heart disease, renal disease). Mean systolic, but not diastolic blood pressure was substantially higher in the aliskiren group (158/91 mmHg vs. 154/89 mmHg in ACE-I/ARB vs. 152/89 mmHg in non-RAS). Mean number of antihypertensive drugs was higher in the aliskiren group compared with the other groups (3.0 drugs vs. 2.5 in ACE-I/ARB vs. 1.6 in non-RAS; p < 0.0001).

CONCLUSIONS

In this large cohort of outpatients with hypertension, aliskiren was used mainly in patients with more severe stages of hypertension and those with concomitant diseases such as diabetes mellitus and impaired renal function. The 3A registry will provide important information about the use and efficacy of aliskiren in a real-life setting.

Direct renin inhibition: from pharmacological innovation to novel therapeutic opportunities

Nowadays, social and economic burden related to cardiovascular and renal diseases still remains extremely high, although there has been a dramatic improvement of diagnostic options and therapeutic strategies reported in the last 30 years. The progressively higher attention towards integrated pharmacological strategies, which are able to interfere with different pathophysiological mechanisms, has certainly led to better control of cardiovascular and renal diseases. In view of the large involvement of the renin-angiotensin system (RAS) in the vast majority of pathophysiological mechanisms leading to the development and progression of cardiovascular and renal diseases, it can be easily understood why it has been long viewed as the 'ideal' target for the pharmacological treatment of several clinical conditions. Recently, besides the well known therapeutic approaches for RAS blockade, based on the use of ACE inhibitors, angiotensin II type 1 receptor antagonists (angiotensin receptor blockers [ARBs]) and aldosterone antagonists, both the scientific and medical community have focused their attention on a novel therapeutic option. In 2007, aliskiren, the first compound of a new drug class, the direct renin inhibitors (DRIs), has become available for clinical use, being a novel and innovative therapeutic option. Aliskiren is able to interfere with the enzymatic activity of renin by blocking the catalytic site of the molecule and inducing an 'upstream' RAS blockade. This leads to a modulation of the biological properties of renin, thus resulting in the missed cleavage of angiotensinogen to angiotensin I. Aliskiren has demonstrated antihypertensive efficacy comparable or even superior to that of other classes of antihypertensive drugs, both in monotherapy and in combination therapies. Its safety and tolerability are comparable with those of other antihypertensive drug classes and almost similar to placebo. In addition, it has been demonstrated to reduce progression of cardiac and renal organ damage in addition to ACE inhibitors or ARBs. An ambitious and large clinical trial programme specifically designed for this innovative antihypertensive drug will evaluate the efficacy of aliskiren in terms of reduced incidence of major cardiovascular and renal outcomes in patients with hypertension and cardiovascular disease, besides the use of optimal (standard) therapeutic strategies, including ACE inhibitors and ARBs.

Enduring direct association of baseline plasma renin activity with all-cause and cardiovascular mortality in hypertensive patients

BACKGROUND

Plasma renin activity (PRA) has been associated with cardiovascular disease mortality (CVD) events among hypertensive patients. We now report a long-term follow-up to assess the enduring association of PRA to CVD and all-cause mortality.

METHODS

Participants (3,791) in a systematic hypertension treatment study had entry systolic blood pressure (BP) ≥140 mm Hg and mean age 52. CVD and all-cause mortality was ascertained for mean of 16 years. Pretreatment PRA was analyzed as a continuous variable, and by tertiles. The 10-year Framingham score was similarly examined. Hazard ratios (HRs) were estimated from multivariate Cox proportional hazard models.

RESULTS

There were 804 deaths, and 360 (45%) were CVD. PRA was associated with all-cause mortality and CVD, but not cancer or non-CVD. Although T3 had lower mean baseline and follow-up systolic BP than T1, (146 vs. 152 mm Hg (P < 0.001) and 135 vs. 139 mm Hg (P < 0.001), respectively), T3 had 37% higher all-cause mortality (HR: 1.37, 95% confidence interval (CI): 1.15-1.63, P < 0.001) and 70% higher CVD mortality (HR: 1.70, 95% CI: 1.29-2.23, P < 0.001) after adjustment. The difference between T3 and T1 in mortality from coronary artery disease and myocardial infarction was more pronounced than for all CVD. PRA also significantly improved CVD risk estimation provided by Framingham.

CONCLUSIONS

These findings extend and reinforce previous evidence that pretreatment PRA has a significant, independent, specific, and direct long-term association with CVD mortality. Moreover, PRA adds significantly to risk identified by the Framingham score.

Measuring and targeting aldosterone and renin in atherosclerosis-a review of clinical data

Our understanding of the development and progression of atherosclerosis has increased substantially over the past decades. A significant role for the renin-angiotensin-aldosterone system (RAAS) in this process has gained appreciation in recent years. Preclinical and clinical studies have associated components of the RAAS with various cardiovascular disease conditions. Classically known for its contribution to hypertension, dysregulation of the system is now also believed to promote vascular inflammation, fibrosis, remodeling, and endothelial dysfunction, all intimately related to atherosclerosis. The reduction in cardiovascular mortality and morbidity, as seen with the use of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, supports the concept that RAAS is involved in the pathogenesis of atherosclerotic disease. However, the underlying molecular mechanisms of the pathophysiology remain to be completely understood. Evidence points toward additional benefit from therapeutic approaches aiming at more complete inhibition of the system and the possible utility of renin or aldosterone in the prediction of cardiovascular outcome. This review will summarize the current knowledge from clinical studies regarding the presumptive role of renin and aldosterone in the prediction and management of patients with atherosclerosis. For this purpose, a literature search was performed, focusing on available clinical data regarding renin or aldosterone and cardiovascular outcome.

Potential benefits of aliskiren beyond blood pressure reduction

There is now clear evidence that reducing blood pressure (BP) with a broad range of agents, including angiotensin converting enzyme inhibitors and angiotensin receptor blockers, improves cardiovascular and renal outcomes. There is also evidence suggesting that these drugs have beneficial effects that are independent of BP lowering. Aliskiren is a direct renin inhibitor that interrupts the renin-angiotensin-aldosterone system (RAAS) at its rate-limiting step. Unlike angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, aliskiren produces a sustained reduction in plasma renin activity and reduces plasma levels of angiotensin II and aldosterone. Preclinical data and clinical trials in high-risk patients using surrogate markers increasingly suggest that aliskiren can reduce the progression of end-organ damage beyond that afforded by BP control. With its unique mechanism of action, combining aliskiren with another RAAS-blocking agent that has a different mechanism of action may provide more comprehensive blockade of the RAAS, potentially conferring additional clinical benefits. Evaluation of these end-organ effects in humans is underway in clinical trials designed to assess the effects of aliskiren alone and in combination with other antihypertensive agents on cardiovascular and renal outcomes.