Prognostic factors in resistant hypertension: implications for cardiovascular risk stratification and therapeutic management

Resistant Hypertension and Related Outcomes in a Cohort of Patients with Cardiorenal Multimorbidity Hospitalized in an Internal Medicine Ward

INTRODUCTION

Resistant hypertension (RH) is characterized by the failure to reach a goal blood pressure despite the administration of three medications at maximally tolerated doses, one of which being a diuretic. RH can be observed in a variety of clinical conditions, such as heart failure and reduced renal function and may confer high cardiovascular risk.

AIM

To evaluate the prevalence of RH and its association with clinical outcomes; the primary outcome was in-hospital mortality and the composite outcome was all-cause of mortality and morbidity in a cohort of patients with cardiorenal multimorbidity hospitalized in an internal medicine ward.

METHODS

We conducted a retrospective analysis of consecutive hypertensive patients with cardiorenal multimorbidity. The composite outcome incorporated all-cause of in-hospital mortality and occurrence of sepsis, pulmonary embolism, acute coronary syndrome, stroke and renal replacement therapy.

RESULTS

We collected data in 141 inpatients with a mean age of 77 years ± 10 (males 65.9 %), estimated glomerular filtration rate of 34 ± 18.6 ml/min with length of stay of 17 ± 12 days. The prevalence of RH was 52.4%. In-hospital mortality was observed in 24 patients (17%) and the composite outcome occurred in 87 patients (61.7%) and among these 74 (85.1%) were patients with RH. Free survival for composite outcome was significantly higher in patients without RH than patients with RH (log rank 7.52, p = 0.006). Resistant hypertension was a risk factor for composite outcome [HR 1.857(C.I. 1.170-2.946, p = 0.009)].

CONCLUSION

In patients with cardiorenal multimorbidity there is a high proportion of RH that represents a risk factor for composite outcome but not for in-hospital mortality.

Arterial Stiffness and its Impact on Cardiovascular Health

PURPOSE OF REVIEW

Cardiovascular diseases are the leading cause of mortality globally. Identifying patients at risk is important to initiate preventive strategies. Over the last few decades, the role of the endothelium and its impact on arterial stiffness have been recognised as playing a pivotal role in cardiovascular disease. This review will focus on the effect of arterial stiffness in different patient cohorts with regard to cardiovascular morbidity and mortality, as well as its use in clinical practice.

RECENT FINDINGS

Arterial stiffness is associated with a range of cardiovascular risk factors and is an independent predictor of cardiovascular mortality. The gold standard for evaluating arterial stiffness is pulse wave velocity. Recently, cardio-ankle vascular index has been implemented as an easy and highly reproducible measure of arterial stiffness. Moreover, certain pharmacologic agents may modify arterial stiffness and alter progression of cardiovascular disease. The endothelium plays an important role in cardiovascular disease. Implementing assessment of arterial stiffness in clinical practice will improve stratification of patients at risk of cardiovascular disease and help modify disease progression.

Resistant and refractory hypertension: two sides of the same disease?

Refractory hypertension (RfH) is an extreme phenotype of resistant hypertension (RH), being considered an uncontrolled blood pressure besides the use of 5 or more antihypertensive medications, including a long-acting thiazide diuretic and a mineralocorticoid antagonist. RH is common, with 10-20% of the general hypertensives, and its associated with renin angiotensin aldosterone system hyperactivity and excess fluid retention. RfH comprises 5-8% of the RH and seems to be influenced by increased sympathetic activity. RH patients are older and more obese than general hypertensives. It is strongly associated with diabetes, obstructive sleep apnea, and hyperaldosteronism status. RfH is more frequent in women, younger patients and Afro-americans compared to RFs. Both are associated with increased albuminuria, left ventricular hypertrophy, chronic kidney diseases, stroke, and cardiovascular diseases. The magnitude of the white-coat effect seems to be higher among RH patients. Intensification of diuretic therapy is indicated in RH, while in RfH, therapy failure imposes new treatment alternatives such as the use of sympatholytic therapies. In conclusion, both RH and RfH constitute challenges in clinical practice and should be addressed as distinct clinical entities by trained professionals who are capable to identify comorbidities and provide specific, diversified, and individualized treatment.

Prognostic Value of C-Reactive Protein in Resistant Hypertension

BACKGROUND

C-reactive protein (CRP) is a biomarker of systemic low-grade inflammation and a cardiovascular risk predictor in several clinical conditions. However, its prognostic value has never been examined in patients with resistant hypertension.

METHODS

In a prospective study, 476 patients with resistant hypertension had CRP levels measured at baseline, together with other clinical laboratory variables, including ambulatory blood pressures (BPs). Primary end points were a composite of major fatal or nonfatal cardiovascular events, all-cause mortality, and cardiovascular mortality. Multiple Cox regression assessed the associations between CRP levels and end points.

RESULTS

Median CRP was 3.8mg/l (interquartile range: 2.0-7.2mg/l). After a median follow-up of 9 years, 103 major cardiovascular events occurred, and 120 patients died, 62 from cardiovascular causes. Patients with CRP levels above the median value had a doubled excess risk of major cardiovascular events (95% confidence interval: 1.29-3.06; P = 0.002) and an 86% higher risk of cardiovascular death (95% confidence interval: 1.07-3.25; P = 0.029), after adjustments for potential confounders including traditional cardiovascular risk factors and ambulatory BP and dipping pattern. A high CRP equally predicted coronary (hazard ratio: 2.04; 95% confidence interval: 1.10-3.76; P = 0.023) and cerebrovascular events (hazard ratio: 2.72; 95% confidence interval: 1.30-5.67; P = 0.007). In interaction and sensitivity analyses, CRP levels were stronger predictors of worse cardiovascular outcomes in younger and obese patients, and in those with uncontrolled ambulatory BPs and with the nondipping pattern.

CONCLUSIONS

In patients with resistant hypertension, elevated serum CRP levels is predictive of worse cardiovascular prognosis above and beyond other cardiovascular risk factors, including ambulatory BP levels and dipping patterns.

Diagnostic accuracy of the Berlin questionnaire in detecting obstructive sleep apnea in patients with resistant hypertension

OBJECTIVES

Obstructive sleep apnea (OSA) is strongly associated with resistant hypertension. The Berlin questionnaire is the most widely used screening tool to identify patients at high risk of having OSA. The objective was to test the diagnostic accuracy of the Berlin questionnaire in detecting OSA in resistant hypertensive patients.

METHODS

A cross-sectional analysis of 422 resistant hypertensive patients [31% men; mean (SD) age 62.4 (9.9) years] submitted to polysomnography (PSG), in whom the Berlin questionnaire was previously applied. OSA was defined by an apnea-hypopnea index of at least 5 per hour and moderate-to-severe OSA by an apnea-hypopnea index of at least 15. Statistical analysis included bivariate comparisons between patients at high and low risk by the Berlin questionnaire, and logistic regression to assess the predictors of agreement between the Berlin questionnaire and PSG. Sensitivity, specificity, positive and negative predictive values and likelihood ratios for the Berlin questionnaire in detecting OSA were calculated.

RESULTS

OSA was diagnosed in 347 patients (82.2%) and moderate-to-severe OSA in 234 patients (55.5%). In patients at high risk, moderate-to-severe OSA was confirmed in 58.3%, whereas in those at low risk, it was excluded in 50.4%. The accuracy of the Berlin questionnaire in detecting OSA was 55.6%. The specificity, sensitivity, positive and negative predictive value of the Berlin questionnaire in detecting moderate-to-severe OSA was 40, 69, 58 and 50%, respectively. The positive and negative likelihood ratios were 1.15 and 0.78, with a very low agreement (kappa = 0.081).

CONCLUSION

In a large cohort of resistant hypertensive patients, the Berlin questionnaire had a low accuracy of identifying patients with OSA and should not be used as a screening method for selecting patients to PSG.

Cardiovascular and renal complications in patients with resistant hypertension

With an increased prevalence, resistant hypertension is recognized as an entity with a high cardiovascular morbidity and mortality. In a large cohort of patients with resistant hypertension, the crude incidence rate of total cardiovascular events reached 4.32 per 100 patient-years of follow-up (19.6 %), with a cardiovascular mortality of 8.3 % (incidence rate of 1.72 per 100 patient-years). Cardiovascular event rates are significantly higher in resistant hypertensives compared with non-resistant (18.0 % versus 13.5 %). In the same way, the prevalence of established cardiovascular and renal disease, as the asymptomatic organ damage (represented by left ventricular hypertrophy, carotid wall thickening, arterial stiffness, and microalbuminuria) is higher in these patients. Many studies have demonstrated a strong association between damage to these organs with higher blood pressure levels, the diagnosis of true resistant hypertension, and refractory hypertension. All efforts should be employed in order to control blood pressure and also to regress and/or prevent subclinical cardiovascular and renal damage. The focus should be on prevention of cardiovascular and renal complications, improving the prognosis of resistant hypertension.

Plasmin in urine from patients with type 2 diabetes and treatment-resistant hypertension activates ENaC in vitro

BACKGROUND

Aberrant filtration of plasminogen from plasma and subsequent activation to plasmin in the urinary space may activate proteolytically the epithelial sodium channel, ENaC. In conditions with chronic albuminuria, this may cause hypertension. It was hypothesized that patients with type 2 diabetes mellitus (T2DM) and treatment-resistant hypertension excrete plasmin(ogen) in urine in proportion to albumin and that plasmin confers to urine the ability to activate ENaC.

METHOD

Patients (n = 113) with T2DM and resistant hypertension, defined as systolic blood pressure (SBP) more than 130 mmHg and/or diastolic blood pressure (DBP) more than 80 mmHg despite use of at least three drugs with one diuretic and one renin-angiotensin system inhibitor, were included. Urine was analyzed for albumin, creatinine, plasmin(ogen), protease activity, and ability to activate inward current in single collecting duct cells.

RESULTS

Mean ambulatory SBP/DBP was 143 ± 1/77 ± 0.7 mmHg; HbA1c 7.35%; and eGFR 81.0 ml/min per 1.73 m (geometric means). Patients with microalbuminuria (39%) and macroalbuminuria (13%) displayed significantly elevated levels of urinary plasmin(ogen) normalized to urine creatinine compared with patients with normal excretion of albumin (48%). Urinary plasminogen correlated significantly to urine albumin. Western immunoblotting and gelatine zymography confirmed active plasmin in urine samples from patients with microalbuminuria and macroalbuminuria. Single collecting duct cells displayed significantly increased, amiloride-sensitive, inward current when superfused with urine from albuminuric patients compared with patients with normal albumin excretion. Urinary plasminogen/creatinine ratio correlated significantly with 24-h ambulatory blood pressure.

CONCLUSION

Aberrant presence of plasmin in preurine may inappropriately activate ENaC in patients with type 2 diabetes and microalbuminuria. This may contribute to treatment-resistant hypertension.

Arterial stiffness as a risk factor for coronary artery disease

Hypertension is a major modifiable risk factor, and clinical trials have demonstrated that successful reduction of elevated blood pressure to target levels translates into decreased risk for the development of coronary artery disease, stroke, heart failure, and renal failure. The arterial system had previously been regarded as a passive conduit for the transportation of arterial blood to peripheral tissues. The physiologic role the arterial system was greatly expanded by the recognition of the central role of the endothelial function in a variety of physiologic processes. The role of arterial function and structure in cardiovascular physiology was expanded with the development of a variety of parameters that evaluate arterial stiffness. Markers of arterial stiffness have been correlated with cardiovascular outcomes, and have been classified as an emerging risk factor that provides prognostic information beyond standard stratification strategies involving hypertension, diabetes, obesity, dyslipidemia and smoking. Multiple epidemiologic studies have correlated markers of arterial stiffness such as pulse-wave velocity, augmentation index and pulse pressure with risk for the development of fatal and nonfatal cardiovascular events. Additionally, measurements of arterial stiffness had clarified the results of clinical trials that demonstrated differing impacts on clinical outcomes, despite similar reductions in blood pressure, as measured by brachial and sphygmomanometry.

Prevalence and associated factors of obstructive sleep apnea in patients with resistant hypertension

BACKGROUND

Obstructive sleep apnea (OSA) syndromes are strongly associated with resistant hypertension, although this has not been systematically examined. The aim of our study was to investigate the prevalence of OSA and its associated factors in a large cohort of resistant hypertensive patients.

METHODS

A cross-sectional analysis with 422 resistant hypertensive patients (31.3% men; mean age = 62.4±9.9 years) submitted to a full-night polysomnography. The presence of OSA was defined by an apnea-hypopnea index (AHI) >5 per hour and moderate/severe OSA was defined by an AHI >15. Statistical analysis included bivariable comparisons between patients with and without moderate/severe OSA and logistic regressions to assess the independent correlates of OSA severity.

RESULTS

Three-hundred forty-seven patients (82.2%) had OSA, and 234 patients (55.5%) had moderate/severe OSA. Patients with moderate/severe OSA were more frequently elderly and obese men with larger waist and neck circumferences, had higher prevalences of diabetes and left ventricular hypertrophy, and had higher proteinuria than patients with no/mild OSA. No difference was found in plasma aldosterone and renin activity. Nighttime systolic blood pressures and pulse pressures were higher in moderate/severe OSA, with lower nocturnal blood pressure fall. In multivariable logistic regression, male sex, older age, diabetes, obesity, increased waist and neck circumferences, and nighttime systolic blood pressure were the independent correlates of moderate/severe OSA.

CONCLUSIONS

Resistant hypertensive patients had a very high prevalence of OSA, and patients with moderate/severe OSA had an adverse ambulatory BP profile, with higher nighttime systolic blood pressures and pulse pressures and higher prevalence of nondipping patterns. Other correlates of OSA severity were mainly demographic-anthropometric variables.

The possibility of resistant hypertension during the treatment of hypertensive patients

Patients with poorly controlled hypertension despite taking at least three different kinds of anti-hypertensive drugs, including diuretics, are considered to have resistant hypertension (RH). The prevalence of RH was reported to be 13% in the Japanese J-HOME study. The incidences of RH in younger and older Japanese individuals should be prospectively investigated in the near future. RH is associated with poor outcomes and various cardiovascular events. In addition, it is frequently associated with older age, obesity, sleep apnea, long-term hypertension, diabetes, dyslipidemia, reduced renal function, microalbuminuria and left ventricular hypertrophy. Some cases of RH exhibit high levels of aldosterone and cortisol, suggesting that endocrine hypertension should be ruled out among RH patients. Carotid baroreceptor activation and renal sympathetic denervation have recently been developed as treatments for RH. In conclusion, we should consider the possibility of RH during the treatment of hypertensive patients who do not achieve appropriate blood pressure control, in order to avoid the early onset of fatal cardiovascular events and reduce medical costs.

Apparent treatment-resistant hypertension among elderly Korean hypertensives: an insight from the HIT registry

The aim of this study was to determine the clinical characteristics of patients with resistant hypertension (RH) and predictors among elderly Korean hypertensives. This prospective, multi-center, observational study evaluated 2439 elderly hypertensive patients between December 2008 and November 2011, who visited secondary hypertension clinics for high blood pressure (BP). Patients were categorized as resistant if their BP was ≥140/90 mm Hg and if they reported using antihypertensive medications from three different drug classes, including a diuretic or drugs from ≥4 antihypertensive drug classes, regardless of BP. Characteristics of patients with RH were compared with those of patients who were controlled with one or two antihypertensive medications after 6-month antihypertensive treatment. In comparison with 837 patients with non-RH, 404 patients with RH were more likely to be aware of their status of high BP before enrollment and have a high baseline systolic BP ≥160 mm Hg, microalbuminuria, high body mass index (BMI) ≥24 kg m(-2) and diabetes mellitus (DM). In drug-naive patients, awareness of hypertension at baseline was the only independent predictor for RH. In elderly Korean hypertensives, BMI (≥24 kg m(-2)), baseline systolic BP (≥160 mm Hg), microalbuminuria, DM and awareness of hypertension showed an association with RH.