Aldosterone Escape With Diuretic or Angiotensin-Converting Enzyme Inhibitor/Angiotensin II Receptor Blocker Combination Therapy in Patients With Mild to Moderate Hypertension

Effect of diuretics on plasma aldosterone and potassium in primary hypertension: A systematic review and meta-analysis

AIM

By contrast with drugs inhibiting the renin-angiotensin-aldosterone system (RAAS), diuretics stimulate renin release by the kidneys. Although plasma aldosterone (PA) is thought to be mainly regulated by RAAS activity, serum potassium has been shown to be an important factor in animal models and humans. Here we perform a systematic review and meta-analysis of randomised controlled trials (RCT) in hypertension investigating the effects of diuretic therapy on PA and the correlation of change in PA with that of potassium and blood pressure (BP).

METHODS

Three databases were searched: MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials (CENTRAL). Titles were first screened by title and abstract for relevance before full-text articles were assessed for eligibility according to a predefined inclusion/exclusion criteria.

RESULTS

A total of 1139 articles were retrieved, of which 42 met the prespecified inclusion/exclusion criteria. The average standardised difference in mean PA was similar for all classes of diuretic: thiazide/thiazide-like 0.299 (95% confidence interval [CI] 0.150, 0.447), loop 0.927 (0.37, 1.49), MRA/potassium-sparing 0.265 (0.173, 0.357) and combination 0.466 (0.137, 0.796), Q = 6.33, P = .097. In subjects untreated with another antihypertensive, there was a significant relationship between change in PA and change in systolic BP but no relationship with the change in potassium.

CONCLUSION

In RCTs of diuretic therapy in hypertension, there is an increase in PA with all classes of diuretic and no significant between-class heterogeneity. Change in PA is not related with potassium but correlates with the change in BP in subjects untreated with another antihypertensive medication.

Effect of diuretics on plasma renin activity in primary hypertension: A systematic review and meta-analysis

AIMS

Plasma renin activity (PRA) is regarded as a marker of sodium and fluid homeostasis in patients with primary hypertension. Whether effects of diuretics on PRA differ according to class of diuretic, whether diuretics lead to a sustained increase in PRA, and whether changes in PRA relate to those in blood pressure (BP) is unknown. We performed a systematic review and meta-analysis of trials investigating the antihypertensive effects of diuretic therapy in which PRA and/or other biomarkers of fluid homeostasis were measured before and after treatment.

METHODS

Three databases were searched: MEDLINE, EMBASE and The Cochrane Central Register of Controlled Trials. Titles were firstly screened by title and abstract for relevancy before full-text articles were assessed for eligibility according to a predefined inclusion/exclusion criteria.

RESULTS

A total of 1684 articles were retrieved of which 61 met the prespecified inclusion/exclusion criteria. PRA was measured in 30/61 studies. Diuretics led to a sustained increase in PRA which was similar for different classes of diuretic (standardised mean difference [95% confidence interval] 0.481 [0.362, 0.601], 0.729 [0.181, 1.28], 0.541 [0.253, 0.830] and 0.548 [0.159, 0.937] for thiazide, loop, mineralocorticoid receptor antagonists/potassium-sparing and combination diuretics respectively, Q = 0.897, P = .826), and did not relate to the average decrease in blood pressure.

CONCLUSION

In antihypertensive drug trials, diuretics lead to a sustained increase in average PRA, which is similar across different classes of diuretic and unrelated to the average reduction in blood pressure.

Zi Shen Huo Luo Formula Enhances the Therapeutic Effects of Angiotensin-Converting Enzyme Inhibitors on Hypertensive Left Ventricular Hypertrophy by Interfering With Aldosterone Breakthrough and Affecting Caveolin-1/Mineralocorticoid Receptor Colocalization and Downstream Extracellular Signal-Regulated Kinase Signaling

Left ventricular hypertrophy (LVH) is an important characteristic of hypertensive heart disease. Renin-angiotensin system (RAS) blockers have been shown to be effective drugs for the reversal of LVH. Clinical and experimental studies have shown that Zi Shen Huo Luo Formula (ZSHLF) can improve the efficacy of perindopril in the treatment of hypertensive LVH, but its mechanism is unclear. This study aimed to investigate the possible mechanism to improve the efficacy of perindopril. First, we identified 23 compounds in ZSHLF by ultra performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) analysis, among which ferulic acid, caffeic acid, vanillic acid, berberine, rutin, quercetin, kaempferol, stachydrine, and tiliroside have been reported to reduce blood pressure and exhibit cardioprotective effects. Second, we treated spontaneously hypertensive rats (SHRs) with perindopril and ZSHLF for 12 continuous weeks and found that chronic use of perindopril could increase the aldosterone (ALD) levels and cause aldosterone breakthrough (ABT). ZSHLF combined with perindopril reduced the ALD levels, interfered with ABT, decreased blood pressure, improved left ventricular diastolic dysfunction, and decreased the collagen volume fraction; these effects were superior to those of perindopril alone. In vitro experiments, ALD-induced cardiomyocytes (H9c2 cells) and cardiac fibroblasts were treated with ZSHLF-containing serum, which suppressed ALD-induced cardiomyocyte hypertrophy and cardiac fibroblast proliferation, increased mineralocorticoid receptor (MR) and Cav-1 colocalization and decreased phosphorylated epidermal growth factor receptor (pEGFR) and phosphorylated extracellular signal-regulated kinase (pERK) protein expression the cells. In conclusion, ZSHLF can interfere with ABT and affect the pathological role of ALD by affecting MR and Cav-1 interactions and EGFR/ERK signaling pathway. These effects represent a possible mechanism by which ZSHLF improves the efficacy of angiotensin-converting enzyme inhibitors (ACEIs) in hypertensive LVH treatment. However, the major bioactive components or metabolites responsible for the effects and the implications of these findings in patients need further verification.

Renal ultrasound and Doppler parameters as markers of renal function and histopathological damage in children with chronic kidney disease

AIM

Doppler ultrasonography can be used to assess the progression of vascular (arterial sclerosis) and parenchymal (glomerular sclerosis and crescents) renal damage. The aim of this study was to evaluate the significance of some sonographic and Doppler parameters as non-invasive markers of glomerular filtration rate (GFR) and renal histopathological damage in children.

METHODS

A cohort of 84 children were enrolled in a case-control study (42 with CKD stages 2-5 and 42 healthy children). GFR was assessed using new improved equation using serum creatinine and cystatin C. Sonar guided renal specimen was obtained and evaluated for the severity of global sclerosis (GS), segmental sclerosis (SS), tubular atrophy (TA), interstitial fibrosis (IF), arterial sclerosis (AS) and arteriolar hyalinosis (AH). The following sonographic and Doppler parameters were assessed in both patients and control group: resistivity index (RI), pulsatility index (PI), atrophic index (AI), mean renal volume, mean renal density, time average velocity (TAV) and body surface area related volume perfusion (BSARVP).

RESULTS

There was significant difference in renal density (P < 0.001), RI (P < 0.001), PI (P = 0.021), TAV (P < 0.001) and BSARVP (P < 0.001) between patients and control group. The cutoff value of RI was 63.5% (sensitivity 83% and specificity 64%). Multivariate analysis revealed that renal density and RI were significant predictors of worsening of estimated GFR (eGFR) in CKD patients.

CONCLUSION

Any increase in the RI and PI values must arouse alarm to the possibility of advancing renal damage. Moreover, RI and PI could fairly predict the degree of glomerular sclerosis and interstitial fibrosis.

Chronic kidney disease: a new look at pathogenetic mechanisms and treatment options

The concept of renoprotection has evolved significantly, driven by improved understanding of the pathophysiology of chronic kidney disease (CKD) and the advent of novel treatment options. Glomerular hyperfiltration, hypertension and proteinuria represent key mediators of CKD progression. It is increasingly recognized that proteinuria may actually be pathological and etiological in CKD progression and not just symptomatic. It initiates a sequence of events involving activation of proinflammatory and profibrotic signaling pathways in proximal tubular epithelial cells with transmission of the disease to the tubulointerstitium and progression to end-stage kidney disease (ESKD). Although the etiology and epidemiology of pediatric CKD differs to that in adults, studies in the various animal models of kidney disease, from obstructive uropathy to glomerulonephritis, have revealed that many common proinflammatory and profibrotic pathways are induced in progressive proteinuric CKD, irrespective of the primary disease. This pathomechanistic overlap therefore translates into the potential for common treatment targets for a wide spectrum of kidney diseases. In this review we therefore discuss the experimental and clinical evidence for an array of prospective future drug treatments of CKD progression. While conceptually promising, clear definitive evidence beyond preclinical data does not exist for many of these treatments, and others are limited by serious adverse effects. More studies are needed before general recommendations can be given.

Deregulation of adipokines related to target organ damage on resistant hypertension

Resistant hypertension (RHTN) includes patients with controlled blood pressure (BP) (CRHTN) and uncontrolled BP (UCRHTN). In fact, RHTN patients are more likely to have target organ damage (TOD), and resistin, leptin and adiponectin may affect BP control in these subjects. We assessed the relationship between adipokines levels and arterial stiffness, left ventricular hypertrophy (LVH) and microalbuminuria (MA). This cross-sectional study included CRHTN (n=51) and UCRHTN (n=38) patients for evaluating body mass index, ambulatory blood pressure monitoring, plasma adiponectin, leptin and resistin concentrations, pulse wave velocity (PWV), MA and echocardiography. Leptin and resistin levels were higher in UCRHTN, whereas adiponectin levels were lower in this same subgroup. Similarly, arterial stiffness, LVH and MA were higher in UCRHTN subgroup. Adiponectin levels negatively correlated with PWV (r=-0.42, P<0.01), and MA (r=-0.48, P<0.01) only in UCRHTN. Leptin was positively correlated with PWV (r=0.37, P=0.02) in UCRHTN subgroup, whereas resistin was not correlated with TOD in both subgroups. Adiponectin is associated with arterial stiffness and renal injury in UCRHTN patients, whereas leptin is associated with arterial stiffness in the same subgroup. Taken together, our results showed that those adipokines may contribute to vascular and renal damage in UCRHTN patients.

Antihypertensive efficacy of angiotensin receptor blockers as monotherapy as evaluated by ambulatory blood pressure monitoring: a meta-analysis

AIMS

Angiotensin receptor blockers (ARBs) are available in different dosages and it is common clinical practice to uptitrate if blood pressure goal is not achieved with the initial dose. Data on the incremental antihypertensive efficacy with uptitration are scarce. It is also unclear if antihypertensive efficacy of losartan is comparable with other ARBs.

METHODS AND RESULTS

We systematically reviewed PubMed/EMBASE/Cochrane databases for all randomized clinical trials until December 2012 reporting 24 h ambulatory blood pressure (ABP) for most commonly available ARBs in patients with hypertension. Reduction in ABP with ARBs was evaluated at 25% of the maximum (max) dose, 50% of the max dose, and at the max dose. Comparison was made between 24 h BP-lowering effect of losartan 50 and 100 mg and other ARBs at 50% max dose and the max dose, respectively. Sixty-two studies enrolling 15 289 patients (mean age 56 years; 60% men) with a mean duration of 10 weeks were included in the analysis. Overall, the dose-response curve with ARBs was shallow with decrease of 10.3/6.7 (systolic/diastolic), 11.7/7.6, and 13.0/8.3 mmHg with 25% max dose, 50% max dose, and with the max dose of ARBs, respectively. Losartan in the dose of 50 mg lowered ABP less well than other ARBs at 50% max dose by 2.5 mmHg systolic (P < 0.0001) and 1.8 mmHg diastolic (P = 0.0003). Losartan 100 mg lowered ABP less well than other ARBs at max dose by 3.9 mm Hg systolic (P = 0.0002) and 2.2 mmHg diastolic (P = 0.002).

CONCLUSION

In this comprehensive analysis of the antihypertensive efficacy of ARBs by 24 h ABP, we observed a shallow dose-response curve, and uptitration marginally enhanced the antihypertensive efficacy. Blood pressure reduction with losartan at starting dose and at max dose was consistently inferior to the other ARBs.

An update on the pathomechanisms and future therapies of Alport syndrome

Alport Syndrome (AS) is an inherited progressive disease that is caused by mutations of the genes encoding the key collagen chains, α3, α4, and α5, which are necessary for the composition of collagen type IV to form a robust glomerular basement membrane (GBM), capable of withstanding the significant biomechanical strain to which the glomerulus is subjected. Progressive loss of the filtration barrier allows excessive proteinuria, which ultimately leads to end-stage kidney disease (ESKD). The evidence for a beneficial renoprotective effect of renin-angiotensin-aldosterone system (RAAS) blockade by angiotensin-converting enzyme (ACE) inhibition and/or angiotensin receptor blockers (ARBs) is well established in AS and recent evidence has shown that it can significantly delay the time to onset of renal replacement therapy and ESKD. Future potential treatments of AS disease progression are evaluated in this review.

Relationship between baseline ET-1 plasma levels and outcome in patients with idiopathic pulmonary hypertension treated with bosentan

OBJECTIVES

To address if baseline endothelin-1 (ET-1) plasma levels might predict clinical worsening (CW) in patients with idiopathic pulmonary hypertension (IPAH) treated with bosentan.

METHODS

Forty-four consecutive patients with IPAH (WHO classes II-III) were included in this study. After an initial assessment (clinical status, pulmonary hemodynamics, samples for adrenomedullin (ADM), ET-1 and brain natriuretic peptide (BNP) plasma levels), patients were treated with bosentan and followed-up for CW.

RESULTS

We observed CW in 24 patients. Actuarial rates of freedom from CW were 74% at 1 year, 56% at 2 years, and 43% at 3 years. Patients with CW had a worse WHO functional class (II/III; no-CW 14/6 vs CW 5/19, p=0.002), six-minute walk-test distance (no-CW 439+94 m vs CW 385+82 m, p=0.04), mean pulmonary artery pressure (no-CW 47.4+10.6mm Hg vs CW 56+12.6mm Hg, p=0.02) and pulmonary vascular resistance (PVR no-CW 12.5+4.8 WU vs CW 16.4+6.3 WU, p=0.03) than the no-CW group. Moreover ET-1 (no-CW 14.1+4.2 pg/ml vs CW 21.3+6.3 pg/ml, p=0.0001), ADM (no-CW 14.9+7 pg/ml vs CW 21.5+10.4 pg/ml p=0.002) and BNP (no-CW 82.8+35.3 pg/ml vs CW 115.4+39.6 pg/ml, p=0.007) plasma levels were significantly higher in the CW group than in the no-CW group. The multivariate Cox proportional hazards model identified WHO class III (RR 4.6, 95%CI 14.6-1.45), ET-1 plasma levels (RR 1.1, 95%CI 2.05-1.01) and PVR (RR 1.2, 95%CI 1.3-1.03) as independent risk factors for CW.

CONCLUSIONS

These data confirm the high rate of CW in patients with IPAH treated with bosentan and document the impact of the endothelin system on CW of these patients.

Canine degenerative myxomatous mitral valve disease: natural history, clinical presentation and therapy

Myxomatous mitral valve disease is a common condition in geriatric dogs. Most dogs affected are clinically asymptomatic for a long time. However, about 30% of these animals present a progression to heart failure and eventually die as a consequence of the disease. Left atrial enlargement, and particularly a change in left atrial size, seems to be the most reliable predictor of progression in some studies, however further studies are needed to clarify how to recognize asymptomatic patients at higher risk of developing heart failure. According to the published data on the natural history of the disease and the results of published studies evaluating the effect of early therapy on delaying the progression of the disease, it seems that no currently available treatment delays the onset of clinical signs of congestive heart failure (CHF). Although the ideal treatment of more severely affected dogs is probably surgical mitral valve repair or mitral valve replacement, this is not a currently available option. The results of several clinical trials together with clinical experience suggest that dogs with overt CHF can be managed with acceptable quality of life for a relatively long time period with medical treatment including furosemide, an angiotensin-converting enzyme inhibitor, pimobendan, and spironolactone.

Characteristics of resistant hypertension: ageing, body mass index, hyperaldosteronism, cardiac hypertrophy and vascular stiffness

Resistant hypertension (RHTN) includes patients whose blood pressure (BP) is controlled with the use of four or more antihypertensive medications, and is referred to as 'controlled resistant hypertension' (CRH). While specifically comparing patients with CRH and uncontrolled resistant hypertension (UCRH), we hoped to identify distinguishing characteristics that would provide insight into factors contributing to resistance to antihypertensive therapies. RHTN patients were identified as controlled (CRH, n=43) or uncontrolled (UCRH, n=47). No statistical differences were observed between the CRH and UCRH subgroups with respect to age and gender. The body mass index, aldosterone-renin ratio and pulse wave velocity (PWV) were significantly higher in UCRH patients. Although both subgroups showed increased cardiac mass, left ventricular mass index was significantly higher in UCRH compared with CRH patients. Multivariate linear regression analysis indicated that PWV was significantly dependent on age in both UCRH and CRH patients; however, the influence of ageing was more pronounced in the former subgroup. Older age, greater vascular stiffness, higher aldosterone levels and greater left ventricular hypertrophy were significantly associated with lack of BP control in patients with RHTN. These findings suggest important possibilities in terms of preventing and better treating RHTN.

Aldosterone excess or escape: Treating resistant hypertension

Aldosterone excess or "escape" can occur after treatment with medications that block the renin-angiotensin-aldosterone system or in undiagnosed primary aldosteronism. Spironolactone is thought to be an important addition to resistant hypertension (RH) treatment. In this study, resistant (RH) and controlled (CH) hypertensives and normotensive patients were submitted to echocardiography, flow-mediated vasodilation, carotid intima-media wall thickness studies, renin plasma activity, and aldosterone plasma levels and plasma and urinary sodium and potassium concentrations at baseline (pre-spironolactone phase). Subsequently, for only RH and CH groups, 25 mg/d spironolactone was added to preexisting treatments over 6 months. Afterwards, these parameters were reassessed (post-spironolactone phase). The RH and CH groups achieved reductions in blood pressure (P<.001), decreases in left ventricular hypertrophy (P<.001), improved diastolic function (Kappa index RH: 0.219 and Kappa index CH: 0.392) and increases in aldosterone concentrations (P<.05). The RH group attained improved endothelium-dependent (P<.001) and independent (P=.007) function. Optimized RH treatment with spironolactone reduces blood pressure and improves endothelial and diastolic function and left ventricular hypertrophy despite the presence of aldosterone excess or escape.