Primary hyperaldosteronism: a frequent cause of residual hypertension after successful endovascular treatment of renal artery disease

Approach to the Patient on Antihypertensive Therapy: Screen for Primary Aldosteronism

Primary aldosteronism (PA) is a condition that is still largely overlooked, resulting in a considerable burden of mortality and morbidity. This is despite decades of clinical and translational research on the deleterious effects of aldosterone on the cardiovascular system and the publication of several guidelines and consensuses on its diagnosis and treatment. One of the main reasons for the low rate of testing is the difficulty of screening patients on antihypertensive therapy that potentially interferes with aldosterone and renin levels and thus confound the interpretation of the aldosterone to renin ratio, the accepted and conventionally used screening test. To avoid interference, usually the therapies that affect the renin-angiotensin aldosterone system are withdrawn and substituted with noninterfering medications. However, in many cases the screening test can be confidently interpreted even when such therapies are not discontinued. In this review, we will evaluate the effects of antihypertensive therapies on the screening test for PA and suggest a practical approach for its interpretation.

Concurrent Primary Aldosteronism and Renal Artery Stenosis: An Overlooked Condition Inducing Resistant Hypertension

To explore the clinical features of coexisting primary aldosteronism (PA) and renal artery stenosis (RAS), we retrospectively analyzed records from 71 patients with PA with RAS and a control group of 121 patients with PA without RAS. Aldosterone-to-renin concentration ratio tests and computerized tomography (CT) scanning of the adrenal and renal arteries were routinely conducted to screen for PA and RAS. Color Doppler flow and/or magnetic resonance imaging were used as substitute testing of patients for whom CT was contraindicated. Standard percutaneous renal arteriography (PTRA) was considered for patients with RAS exceeding 70% based on non-invasive tests and for those without PTRA contraindications. The patients with PA with RAS were further divided into severe (RAS>70%) and moderate (50% < RAS <70%) RAS groups. The prevalence of RAS among PA patients was 6.9% (71/1,033), including 3.2% (33/1,033) with severe RAS. Compared with the PA without RAS group, the severe RAS group showed higher levels of systolic blood pressure (SBP) (171.82 ± 18.24 vs. 154.11 ± 18.96 mmHg; P < 0.001) and diastolic BP(DBP) (110.76 ± 15.90 vs. 91.73 ± 12.85 mmHg; P < 0.001) and prevalence of resistant hypertension (RH) (90.9 vs. 66.9%; P = 0.008), whereas the moderate RAS group merely showed higher DBP (98.63 ± 14.90 vs. 91.73 ± 12.85 mmHg; P = 0.006). The direct renin concentrations (DRCs) (5.37 ± 3.94 vs. 3.71 ± 2.10 μU/mL; P < 0.001) and false-negative rate (33.8 vs. 3.3%; P < 0.01) of PA screening tests were significantly higher in the PA with RAS group than in the control group, but only in severe RAS group, in subgroup analysis. Among patients who underwent successful treatment for severe RAS, mean DRC decreased from 11.22 ± 9.10 to 3.24 ± 2.69 μIU/mL (P < 0.001). Overall, the prevalence of RH decreased from 81.7 to 2.8% (P < 0.001) when both PA and RAS were treated with standard methods. PA with concurrent severe RAS is a condition that induces RH. PA can be easily missed in patients with coexisting RAS. RAS patients with RH after successful revascularization for RAS should be evaluated for coexisting PA.

Clinical characteristics of concurrent primary aldosteronism and renal artery stenosis: A retrospective case-control study

Background: Rare cases of concurrent primary aldosteronism (PA) and renal artery stenosis (RAS) have been reported. Methods: In this retrospective case-control study, we selected a cohort of 10 PA with RAS patients and a control group of 20 PA without RAS patients from January 1, 2006, to January 1, 2016.  Results: All patients presented with refractory hypertension, and a nonstatistically significant trend toward lower mean serum potassium was seen in the PA with RAS group (p =.07). PA with RAS patients had lower mean orthostatic aldosterone-to-renin ratios (38.4 ± 41.4 ng dL^-1/ng mL^-1 h^-1 vs. 87.4.4 ± 38.4 ng dL^-1/ng mL^-1 h^-1, respectively; p < .01) and a higher false-negative rate (50% vs. 15%, respectively; p < .05) compared with controls. All misdiagnosed patients had the diagnosis of PA confirmed when we revaluated the repeated screening and confirmative tests because of residual hypertension or hypokalemia after successful revascularization of renal artery stenosis.  Conclusions: PA is easily missed in patients with RAS because of the high false-negative rate for screening tests. RAS patients with residual hypertension after successful renal angioplasty should be monitored for coexisting PA. Reevaluation of screening and confirmatory tests is helpful in establishing the correct diagnoses.

[Association of renovascular hypertension and primary aldosteronism]

INTRODUCTION

Renal artery stenosis is rarely associated with Conn adenoma.

CASE REPORT

We report a 27-year-old male patient who presented in 2001 with a severe high blood pressure associated with hypokaliemia. Radiologic investigations showed a left renal artery stenosis with agenesis of left kidney. A left nephrectomy was performed and blood pressure returned to normal with a single antihypertensive drug. Five years later, the patient again presented with severe high blood pressure. Laboratory studies revealed a low serum potassium level at 2.8 mmol/L associated with high urinary potassium excretion (84 mmol/24h) and a very high aldosterone/renin ratio (>462). Abdominal CT scan demonstrated a right adrenal mass. The patient underwent a right adrenalectomy (adenoma). Blood pressure returned to normal with a single antihypertensive. Serum potassium levels as well as aldosterone/renin ratio normalized.

CONCLUSION

We discussed whether the association between these two entities is merely fortuitous or conversely based on a causal relationship.

[Effects of endovascular therapy for renal artery stenosis on blood pressure and renal function: retrospective analysis of an unselected patient collective from 1994 to 2007]

BACKGROUND

A retrospective analysis of the long-term success rates of endoluminal therapy of renal artery stenosis in a university hospital was carried out.

MATERIAL AND METHODS

Preinterventional and postinterventional data contained in the clinical records of all 104 patients who underwent percutaneous transluminal angioplasty (PTA, 25 patients) or stent PTA (79 patients) from 01 January 1994 to 31 December 2007, were documented using an electronically structured questionnaire and a time period classification. Subgroup analyses and statistical calculations were done using t-tests for joint random samples.

RESULTS

At day 1 postintervention all patients showed a statistically significant decrease in mean systolic blood pressure (all patients: p=0.002, stent PTA group: p=0.023, PTA group: p=0.022). The significant decrease in mean systolic blood pressure persisted in years 1 and 2 postintervention (all patients: p=0.009 and 0.007, stent PTA group: p=0.039 and 0.015, respectively). Mean blood pressure values remained constant during the other time periods analyzed. In patients with a stent PTA carried out between 2001 and 2007 there was no significant reduction of prescribed antihypertonic drugs (p=0.023 and p=0.046, respectively). Mean serum creatinine concentrations decreased during years 1 and 2 postintervention and increased starting in year 3. In patients with elevated serum creatinine levels prior to the intervention the increase in mean serum creatinine level started in year 5.

CONCLUSIONS

Endoluminal therapy of arteriosclerotic renal artery stenosis delays further deterioration of renal function and stabilizes blood pressure as well as the number of prescribed antihypertonic drugs. This can be considered a response to treatment in view of the mostly chronic progressive course of the disease.

Aldosterone-receptor antagonism in hypertension

The role of the renin-angiotensin-aldosterone system (RAAS) in hypertension has since long been recognized and aldosterone has been acknowledged as one of the key hormones in the pathophysiology, not only in primary aldosteronism but also in essential hypertension and drug-resistant hypertension. Aldosterone-receptor antagonists (ARAs) are increasingly used in patients with resistant hypertension, often with impressive results. However, definitive evidence for the benefit of ARAs in these patients from randomized, controlled trials is lacking. This review gives an overview of the current data on this topic. Future studies should focus on the identification of factors that are able to predict the response to treatment, as to select patients who will benefit most from treatment with ARAs. On the basis of the current knowledge, we recommend prescription of ARAs to patients with primary aldosteronism, resistant hypertension and patients with hypertension and hypokalemia.

A case of primary aldosteronism associated with renal artery stenosis and preclinical Cushing's syndrome

We identified a left adrenal tumor, left renal atrophy, and left renal artery stenosis (RAS) in a 52-year-old man by MRI/magnetic resonance angiography (MRA) during evaluation of hypertension. Laboratory tests revealed hypokalemia, a high plasma aldosterone concentration (PAC), low plasma renin activity (PRA), and normal plasma cortisol. An excessive response of aldosterone and cortisol to adorenocorticotrophic hormone (ACTH) was found upon selective sampling of the left adrenal vein. Selective renal venous sampling showed a left/right renal venous PRA ratio of 1.7. A dexamethasone (8 mg) suppression test showed insufficient suppression of cortisol. We diagnosed this patient as having aldosterone-producing adrenal adenoma (APA) associated with renovascular hypertension (RVH) and preclinical Cushing's syndrome. As an initial treatment, percutaneous transluminal renal angioplasty was performed. Postoperatively, the patient's blood pressure decreased. One month later, the tumor was removed by complete laparoscopic left adrenalectomy. Postoperatively, blood pressure decreased further and both PAC and PRA were normalized. However, antihypertensive therapy could not be completely stopped. The renal dysfuntion that occurred prior to treatment seemed to prevent complete normalization of blood pressure.

Aldosterone, mineralocorticoid receptors, and vascular inflammation

PURPOSE OF REVIEW

Aldosterone and its mineralocorticoid receptor represent an ancient signaling system. Indeed, the mineralocorticoid receptor is older than its agonist. Both have probably served various functions through the eons and salt preservation may be relatively recent. A large body of evidence suggests that aldosterone conducts signaling in vascular cells and contributes substantially to vascular remodeling and target organ damage. A blood pressure and salt balance-independent effect was first observed in two large heart failure trials.

RECENT FINDINGS

Mineralocorticoid receptor blockade has now been shown to reduce proteinuria even in the face of angiotensin converting enzyme inhibition and AT1 receptor blockade. Mineralocorticoid receptor blockade effectively reduces target organ damage in every hypertensive model tested, irrespective of circulating renin and aldosterone levels. Protection is also observed in nonhypertensive diabetic and hyperlipidemic models. Signaling in vascular cells involves primarily the mitogen activated protein kinase pathway with participation of the epidermal growth factor receptor. Novel signaling molecules have been shown to participate in aldosterone-mediated actions including the murine double-minute type 2 protein that participates in antiapoptotic and proliferative effects. Clinically, mutations in the mineralocorticoid receptor have shed additional light on its importance.

SUMMARY

A resurgence of interest in aldosterone reflects its importance and clinical relevance for vascular remodeling and target organ damage.