Left ventricular remodeling and renal function in never-treated essential hypertension

Retinal vascular caliber associated with cardiac and renal target organ damage in never-treated hypertensive patients

OBJECTIVE

The aim of this study was to assess the relationship between retinal vascular caliber and target organ damage in HT patients.

METHODS

Data were collected on cardiac, renal, vascular, and retinal variables in 88 consecutive never-treated HT subjects. Retinal vascular calibers were measured from fundus photographs by using a semi-automated computer-assisted program and summarized as CRAE and CRVE.

RESULTS

Mean CRAE and CRVE were significantly lower in patients with left ventricular hypertrophy (left ventricular mass ≥110 g/m² for women, 125 g/m² for men) than in those with normal left ventricular (CRAE: 129.4±3.7 vs 138.2±2.3 μm; P=.04; CRVE: 195.6±4.4 vs 209.8±2.7 μm; P=.008). CRAE and CRVE were negatively correlated with urinary albumin excretion (β±SE=-15.4±3.2, P<.0001 and β±SE=-11.9±4.4, P=.001, respectively) but were not correlated with estimated glomerular filtration rate (P=.21 and P=.75, respectively), carotid-to-femoral pulse wave velocity (P=.24 and P=.14), or carotid augmentation index (P=.43 and P=.16).

CONCLUSION

In never-treated HT patients, reduced CRAE and CRVE were associated with cardiac and renal preclinical damage, ie, left ventricular hypertrophy and albuminuria, but not estimated glomerular filtration rate or vascular stiffness.

Influence of chronic kidney disease on cardiac structure and function

Chronic kidney disease (CKD), the presence of kidney dysfunction and/or damage, is a worldwide public health issue. Although CKD is independently associated with various subtypes of cardiovascular diseases, a recent international collaborative meta-analysis demonstrates that CKD is particularly strongly associated with heart failure, suggesting its critical impact on cardiac structure and function. Although numerous studies have investigated the association of CKD and cardiac structure and function, these studies substantially vary regarding source populations and methodology (e.g., measures of CKD and/or parameters of cardiac structure and function), making it difficult to reach universal conclusions. Nevertheless, in this review, we comprehensively examine relevant studies, discuss potential mechanisms linking CKD to alteration of cardiac structure and function, and demonstrate clinical implications as well as potential future research directions. We exclusively focus on studies investigating both CKD measures, kidney function (i.e., glomerular filtration rate [GFR], creatinine clearance, or levels of filtration markers), and kidney damage represented by albuminuria, since current international clinical guidelines of CKD recommend staging CKD and assessing its clinical risk based on both GFR and albuminuria.

Presence of albuminuria predicts left ventricular mass in patients with chronic systemic arterial hypertension

BACKGROUND

Increased left ventricular mass (LVM) is known to predict cardiovascular morbidity and mortality. LVM is high in patients with advanced kidney disease. Our aim was to study the relationship between renal parameters and LVM in hypertensive subjects at high risk of cardiovascular disease.

DESIGN

Cardiac MRI was performed in 527 patients participating in the single-centre SMART cohort study. Participants free from previous symptomatic coronary heart disease but with a history of hypertension were recruited. Subjects were screened for cardiovascular risk factors in a standardized way. Multivariable linear regression was used to study the relationship of both estimated glomerular filtration rate (eGFR) and presence of albuminuria with left ventricular mass.

RESULTS

Mean LVM was 121 g for men (SD 26) and 87 g for women (SD 20). Mean eGFR was 82 mL/min/1.73 m(²) (SD 19). A total of 73 patients (14%) had albuminuria. After adjusting for known determinants of LVM (height, weight, sex and age) eGFR did not relate to LVM while presence of albuminuria did (mean change in LVM per 10 mL/min/1.73 m(2) change in eGFR 0.79 g, 95% CI -0.33 to 1.91, P = 0.17, mean change in LVM in presence vs. absence of albuminuria 9.9 g, 95% CI 4.33 to 15.45, P = 0.001). Additional adjustment for systolic blood pressure did not change results (B for eGFR 0.54, 95% CI -0.58 to 1.66, P = 0.35, B for albuminuria 9.09, 95% CI 3.57 to 14.60, P = 0.001).

CONCLUSIONS

In this study in hypertensive patients with high vascular risk, albuminuria was related to increased LVM and eGFR was not.

Subclinical nephrosclerosis is linked to left ventricular hypertrophy independent of classical atherogenic factors

Recently, cardio-renal interactions have been considered to be important and it has been demonstrated that mild renal dysfunction is associated with left ventricular hypertrophy (LVH). However, the correlation between LVH and subclinical renal damage is unclear. We investigated this association by assessing pretransplant biopsies from living kidney donors with normal renal function. We retrospectively categorized 238 living kidney donors into tertiles according to the percentage of global glomerulosclerosis (%GGS) observed in pretransplant biopsies (low, 0-3.45% (n=80); moderate, 3.46-11.76% (n=78); high, ⩾11.77% (n=80)) to analyze trends in their left ventricular mass index (LVMI) measured by echocardiography and baseline factors. LVH was defined as LVMI >110 g m(-2) in female and >125 g m(-2) in male subjects. We used a logistic regression model to evaluate any correlations between %GGS and LVH. LVMI increased significantly with increasing tertiles of %GGS, as did the prevalence of left ventricular remodeling and LVH. According to multivariate logistic regression analysis, subjects with high %GGS tertiles had a sevenfold greater risk of LVH than did those with low tertiles, even after adjusting for age, sex, systolic blood pressure, history of diabetes mellitus, total serum cholesterol and glomerular filtration rate (GFR) measured by a radioisotopic technique. There is an association between GGS and LVH in subjects with normal renal function. This association is significant after adjustment for age, sex, blood pressure, GFR and other atherogenic factors.

Determinants of kidney oxygen consumption and their relationship to tissue oxygen tension in diabetes and hypertension

The high renal oxygen (O(2) ) demand is associated primarily with tubular O(2) consumption (Qo(2) ) necessary for solute reabsorption. Increasing O(2) delivery relative to demand via increased blood flow results in augmented tubular electrolyte load following elevated glomerular filtration, which, in turn, increases metabolic demand. Consequently, elevated kidney metabolism results in decreased tissue oxygen tension. The metabolic efficiency for solute transport (Qo(2) /T(Na) ) varies not only between different nephron sites, but also under different conditions of fluid homeostasis and disease. Contributing mechanisms include the presence of different Na(+) transporters, different levels of oxidative stress and segmental tubular dysfunction. Sustained hyperglycaemia results in increased kidney Qo(2) , partly due to mitochondrial dysfunction and reduced electrolyte transport efficiency. This results in intrarenal tissue hypoxia because the increased Qo(2) is not matched by a similar increase in O(2) delivery. Hypertension leads to renal hypoxia, mediated by increased angiotensin receptor tonus and oxidative stress. Reduced uptake in the proximal tubule increases load to the thick ascending limb. There, the increased load is reabsorbed, but at greater O(2) cost. The combination of hypertension, angiotensin II and oxidative stress initiates events leading to renal damage and reduced function. Tissue hypoxia is now recognized as a unifying pathway to chronic kidney disease. We have gained good knowledge about major changes in O(2) metabolism occurring in diabetic and hypertensive kidneys. However, further efforts are needed to elucidate how these alterations can be prevented or reversed before translation into clinical practice.

Association of heart rate and left ventricular structure in a rural population in Korea

Abstract We investigated the association of heart rate (HR) and estimated glomerular filtration rate (eGFR) with left ventricular (LV) structure in a multi-rural cohort project in Korea. A total of 3215 subjects were analyzed for factors related to Echo-LV mass index (LVMI). eGFR was positively associated with both types of LVMI whereas HR was negatively associated with both. Odd ratios (ORs) (highest versus lowest quartiles) for LVMI by height(2.7) were significant for HR (OR: 0.441, p = 0.0035 in males; OR: 0.638, p = 0.0226 in females), and for eGFR (OR:1.643, p = 0.0145) in females. In conclusion, in addition to age, systolic blood pressure and body mass index, eGFR is positively associated with echocardiographic LVMI and HR is negatively associated with echocardiographic LVMI.

Pulse pressure, arterial stiffness, and end-organ damage

Whereas larger arteries participate in the dampening of blood pressure (BP) oscillations resulting from intermittent ventricular ejection, smaller arteries steadily deliver an adequate supply of blood from the heart to the peripheral organs. Numerous active mechanisms are involved in this process. Cyclic stress acts differently from steady stress, inducing stronger and stiffer material of the vessel wall than under static conditions. Cyclic strain participates in the phenotypic plasticity of smooth muscle cells, initiates transduction mechanisms and induces the transcriptional profile of mechanically induced genes. Finally, the autoregulatory mechanism protecting the brain, heart and kidney from cardiovascular (CV) damage differ markedly according to their localization. Whereas the heart is dependent on pulsatile forces, owing to the diastolic perfusion of coronary arteries, the brain and the kidney are rather influenced by steady mechanical forces. For the kidney, the transmission of pulsatile pressure may greatly contribute to glomerular sclerosis in the elderly.

Treatment of hypertension with renin-angiotensin system inhibitors and renal dysfunction: a systematic review and meta-analysis

BACKGROUND

To determine whether inhibitors of the renin-angiotensin system (RAS) reduce the incidence of renal dysfunction when compared to other antihypertensive treatments in patients with essential hypertension and no pre-existent renal disease.

METHODS

The search strategy used the Cochrane Library, Medline, previous meta-analyses, and journal reviews. The selection criteria included randomized, controlled trials of antihypertensive drugs that compared a RAS inhibitor with another treatment in essential hypertension. Studies that specifically enrolled only patients with diabetes or renal disease were not included. The quality assessment and data extraction of studies were performed by two independent reviewers. Effects on dichotomous renal outcome (serum creatinine (SCreat) higher than a prespecified value, doubling of SCreat or end-stage renal disease) and secondary continuous marker of renal outcome (change in SCreat) were calculated using Peto's method.

RESULTS

33,240 patients met the inclusion criteria for studies with a dichotomous outcome and 10,634 patients for studies with a continuous outcome. The mean follow-up was 42 ± 13 months. Patients randomized to RAS inhibitors did not show a significant reduction in the risk of developing renal dysfunction as compared to other antihypertensive strategies (odds ratio = 1.05; 95% confidence interval (CI) 0.89-1.25; P = 0.54). There was no significant difference in change of SCreat between groups (mean difference = 0.0005 mg/dl; 95% CI -0.0068 to 0.0077 mg/dl; P = 0.91).

CONCLUSION

In patients with essential hypertension and no pre-existent renal disease, prevention of renal dysfunction is not significantly different with RAS inhibitors when compared to other antihypertensive agents.

Prevalence of left-ventricular hypertrophy in hypertension: an updated review of echocardiographic studies

Left-ventricular hypertrophy (LVH) is a cardinal manifestation of hypertensive organ damage associated with an increased cardiovascular (CV) risk. We reviewed recent literature on the prevalence of LVH, as assessed by echocardiography, in order to offer an updated information on the magnitude of subclinical alterations in LV structure in contemporary human hypertension. A MEDLINE search using key words 'left ventricular hypertrophy', 'hypertension', 'echocardiography' and 'cardiac organ damage' was performed in order to identify relevant papers. Full articles published in English language in the last decade, (1 January 2000-1 December 2010), reporting studies in adult or elderly individuals, were considered. A total of 30 studies, including 37,700 untreated and treated patients (80.3% Caucasian, 52.4% men, 9.6% diabetics, 2.6% with CV disease) were considered. LVH was defined by 23 criteria; its prevalence ranged from 36% (conservative criteria) to 41% (less conservative criteria) in the pooled population. LVH prevalence was not different between women and men (range 37.9-46.2 versus 36.0-43.5%, respectively). Eccentric LVH was more frequent than concentric hypertrophy (range 20.3-23.0 versus 14.8-15.8, respectively, P<0.05); concentric phenotype was found in a consistent fraction (20%) of both genders. Despite the improved management of hypertension in the last two decades, LVH remains a highly frequent biomarker of cardiac damage in the hypertensive population. Our analysis calls for a more aggressive treatment of hypertension and related CV risk factors leading to LVH.

Echocardiographic and tissue Doppler imaging alterations associated with spontaneous canine systemic hypertension

BACKGROUND

Feline systemic arterial hypertension (SHT) is associated with a wide spectrum of left ventricular (LV) geometric patterns as well as diastolic, and to a lesser extent, systolic myocardial dysfunction. However, little is known about SHT-related cardiac changes in dogs.

HYPOTHESIS

SHT in dogs is responsible for morphological and functional cardiac alterations.

ANIMALS

Thirty dogs with spontaneous untreated SHT and 28 age- and body weight-matched healthy dogs as controls.

METHODS

Prospective observational study. Conventional echocardiography and 2-dimensional color tissue Doppler imaging were performed in SHT dogs by trained observers and compared with controls.

RESULTS

Forty-seven percent of SHT dogs (14/30) had diffuse concentric hypertrophy. None had left atrial dilatation and 10/30 (33%) had aortic insufficiency (AoI) associated with proximal aortic dilatation. Longitudinal diastolic left ventricular free wall (LVFW) motion was altered in all SHT dogs at the base (early to late diastolic wave ratio, E/A = 0.5 ± 0.1 versus 1.3 ± 0.3 for controls, P < .0001) and the apex (E/A = 1.6 ± 1.7 versus 3.9 ± 3.1, P < .05). Longitudinal motion of the interventricular septum at the base (E/A = 0.7 ± 0.4 versus 1.1 ± 0.1, P < .01) and radial LVFW motion in the subendocardium (E/A = 0.9 ± 0.5 versus 1.6 ± 0.3, P < .01) were also altered in dogs with SHT. Longitudinal LVFW systolic velocities and gradients were also significantly decreased (P < .05) in SHT dogs.

CONCLUSION AND CLINICAL IMPORTANCE

As in SHT in cats, SHT in dogs is associated with myocardial dysfunction independently of the presence of myocardial hypertrophy. However, unlike feline SHT, it results in a homogeneous LV geometric pattern with a relatively high prevalence of AoI.

Comparison of left ventricular mass in normotensive type 2 diabetes mellitus patients with that in the nondiabetic population

Cardiovascular disease is increased in individuals with type 1 or type 2 diabetes mellitus (DM). Left ventricular hypertrophy (LVH), which is an ominous prognostic sign and an independent risk factor for cardiac events, is often present in type 2 DM patients. The aim of our cross-sectional study was to evaluate the prevalence of LVH, and risk factors for its development, in normotensive type 2 diabetic patients without antihypertensive medication. The objectives of the study were to find out the prevalence of high left ventricular mass (LVM) in normotensive type 2 diabetic patients and compare it with nondiabetics and to uncover the risk factors for the development of high LVM in normotensive type 2 diabetic patients. A total of 130 age- and sex-matched subjects were selected (65 cases, diabetic normotensive, and 65 controls, nondiabetic normotensive) and baseline data were collected. LVM and left ventricular mass index (LVMI) were calculated using echocardigraphic parameters and body surface area. LVMI was significantly higher in patients with type 2 DM compared with age-, sex-matched healthy population (104.9 ± 21 vs. 78.5 ± 22.7 g/m², respectively; P < 0.05). BMI, HbA1c, and duration of diabetes were significantly associated with LVH whereas sexes, age, PPBS, were not.

Impact of left ventricular hypertrophy on the time-course of renal function in hypertensive patients – a subanalysis of the CASE-J trial –

BACKGROUND

In this subanalysis of the CASE-J, which was conducted to compare the effects of candesartan and amlodipine in Japanese high-risk hypertensive patients, THE ASSOCIATION OF LEFT VENTRICULAR HYPERTROPHY (LVH) WITH RENAL FUNCTION IS CLARIFIED.

METHODS AND RESULTS

Patients were divided into 2 groups: 1,082 patients with LVH and 2,119 patients without LVH. The primary endpoint was the change in the estimated glomerular filtration rate (eGFR). The eGFRs were increased from 63.6 to 65.1 ml · min(-1) · 1.73 m(-2) in patients with LVH and from 63.6 to 68.5 ml · min(-1) · 1.73 m(-2) in those without LVH. The improvement in the eGFR was greater in patients without LVH than in those with LVH (P=0.004). In patients with chronic kidney disease (CKD) patients, the eGFR increased from 52.7 to 60.5 ml · min(-1) · 1.73 m(-2) in patients without LVH, but from 53.1 to 57.2 ml · min(-1) · 1.73 m(-2) in those with LVH (P<0.001, patients without LVH vs patients with LVH). Furthermore, because the eGFR changed from 76.5 to 75.4 ml · min(-1) · 1.73 m(-2) in patients without CKD but with LVH, and from 76.5 to 77.5 ml · min(-1) · 1.73 m(-2) in those without either CKD or LVH, the final eGFR was higher in patients without LVH than in those with LVH (P=0.048).

CONCLUSIONS

LVH related to the time-course of renal function in Japanese hypertensive patients.

Pulse pressure is an independent determinant of renal function decline during treatment of essential hypertension

BACKGROUND

In large epidemiological studies and using serum creatinine or estimates of glomerular filtration rate (GFR), blood pressure has emerged as a predominant determinant of the age-associated decline in renal function.

METHODS

The present longitudinal study (median follow-up period of 5.8 years) was conducted in 132 never-treated patients with essential hypertension at baseline. The effect of treatment on the GFR and effective renal plasma flow, estimated by urinary clearances of isotopic markers, was assessed.

RESULTS

Satisfactory control of hypertension (<140/90 mmHg) was achieved in 57% of the population. During follow-up, the yearly change in the GFR was -1.72+/-0.21 ml/min per year (mean+/-SEM). In univariate regression analysis, the change in the GFR was correlated with baseline pulse pressure (r=-0.27, P=0.002), whereas no influence of systolic, diastolic or mean blood pressures, as well as baseline albuminuria or left ventricular mass index, was found. Multivariate logistic regression analysis showed that only baseline pulse pressure conveyed a significant odds ratio of accelerated decline of GFR (>median of 1.5 ml/min per year), independently of age, baseline GFR, mean blood pressure and other known cardiovascular risk factors. No influence of the type of antihypertensive treatment (64% of the population had received angiotensin-converting enzyme inhibitor) was detected.

CONCLUSION

Pulse pressure (a marker of arterial stiffening) is suggested as an independent determinant of the treatment-associated decline in renal function in essential hypertension. No influence of target organ damage (albuminuria of left ventricular hypertrophy) was detected.

Left Ventricular Geometry and Renal Function in Hypertensive Patients With Diastolic Heart Failure

BACKGROUND

The objective is to define the relationship between cardiac geometry and renal function in hypertensive subjects with and without diastolic heart failure (DHF).

METHODS

This is a prospective observational study in a tertiary-care teaching institute in a 15-month period of consecutive hospitalized hypertensive patients. Patients on dialysis therapy or with atrial fibrillation, systolic heart failure, gross proteinuria, and glomerular diseases were excluded. Two-dimensional echocardiography was performed and stable glomerular filtration rate (GFR) was calculated by using the Modification of Diet in Renal Disease formula. Patients were classified into stage 1 to 5 chronic kidney disease (CKD).

RESULTS

Five hundred forty hypertensive patients were separated into 2 groups: 286 patients with DHF and 254 patients without DHF. Mean age was 69.1 +/- 13.7 (SD) years in general. In patients with DHF, from stages 1 to 5 CKD, there was a significant graded increase in left ventricular mass index (from 117.3 to 162.4 g/m(2)) and relative wall thickness (from 0.42 to 0.52) and a significant graded decrease in aortic cusp separation (from 1.85 to 1.55 cm). Among echocardiographic variables, left ventricular mass index and relative wall thickness were associated inversely and aortic cusp separation was associated directly with GFR. In the absence of DHF, only left ventricular mass index was associated inversely with GFR, suggesting a prominent role of aortic cusp separation and relative wall thickness in the variability in GFR in patients with DHF through a hemodynamic disturbance.

CONCLUSION

Hemodynamic alterations have a prominent role in the variability of GFR in patients with CKD with DHF. Adverse cardiac geometry is linked to the severity of CKD in hypertensive patients, raising the possibility of preserving both cardiac and renal function by means of hypertension control.

Properties Permitting the Renal Cortex to Be the Oxygen Sensor for the Release of Erythropoietin: Clinical Implications

The PO2 at this site where erythropoietin release is regulated should vary only when the hemoglobin concentration changes in capillary blood. The kidney cortex is an ideal location for this O2 sensor for four reasons. First, it extracts a small proportion of the oxygen that is delivered in each liter of blood; this makes the PO2 signal easier to recognize. Second, there is a constant ratio of the work performed (consumption of O2) to the renal blood flow rate (delivery of O2). Third, the high renal blood flow rate improves diffusion of O2 from capillaries to this O2 receptor. Fourth, a high renal cortical PCO2 prevents an additional shift of the O2:hemoglobin dissociation curve by other factors from being a confounding variable. This suggests that the GFR and the renal blood flow rate should be examined in patients with unexplained anemia or erythrocytosis.

Rationale and design of a study to evaluate management of proteinuria in patients at high risk for vascular events: the IMPROVE trial

Declining kidney function predicts increasing cardiovascular risk in people with hypertension. Microalbuminuria is a marker for cardiovascular risk and declining kidney function. Agents that block the renin-angiotensin-aldosterone system (RAAS), notably angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs), reduce proteinuria and microalbuminuria, lower blood pressure and slow the progression of proteinuric kidney disease. Evidence is accumulating that the combination of an ACE inhibitor and an ARB is the optimal means of RAAS blockade in this setting, slowing the progression of nephropathy independently of blood pressure lowering to a greater degree than can be achieved using maximum approved doses of either agent alone. However, the emerging therapeutic potential of ACE inhibitor/ARB combination therapy in hypertensive kidney disease requires further characterization. The Irbesartan in the Management of PROteinuric patients at high risk for Vascular Events trial aims to determine definitively whether the combination therapy of an ARB, irbesartan and an ACE inhibitor, ramipril, is more effective than ramipril alone in reducing the urinary albumin excretion rate in patients at high cardiovascular risk with hypertension and proteinuria or microalbuminuria.

Consequences of elevated pulse pressure on renal function

Peripheral pulse pressure (PP) is a marker of aging-associated arterial stiffening after the fifth decade. In addition, PP has emerged as a strong predictor of cardiovascular morbidity and mortality. A study of the relationship between renal function and aging of the arterial system using reliable methods of estimating renal haemodynamics (effective renal plasma flow) and function (glomerular filtration rate; GFR) was thus undertaken in a large number of never-treated individuals with essential hypertension. In 212 patients with isolated systolic hypertension, there was an inverse correlation between GFR and PP, but the correlation did not persist after adjustment for age. In fact, the deleterious effect of PP on GFR was observed, independent of age and mean arterial pressure, only in patients aged 60 years and over. In contrast, no clear influence of PP on GFR was detected in patients aged 40 years and over but less than 60 years and in those younger than 40 years. It is thus proposed that PP may have a detrimental influence on the age-related decline in GFR. Prospective studies on the influence of antihypertensive agents with possible effects on peripheral and central PP on the progressive decline of GFR are required.

Chronic Kidney Disease as a Situation of High Added Risk in Hypertensive Patients

Recent guidelines for the management of hypertension have recognized the relevance of renal function on cardiovascular prognosis of hypertensive patients. In fact, growing evidences have confirmed that as soon as renal function exhibits minor derangements, cardiovascular risk starts a continuous rise until the development of end-stage renal disease. Both estimated glomerular filtration rate and urinary albumin excretion are associated with an increased incidence of cardiovascular events and death among hypertensive patients and in general population. Consequently, hypertensive patients presenting with chronic kidney disease are considered by guidelines as high-risk patients, and strict blood pressure control should be considered as a part of an integrative therapeutic approach, including correction of anemia, treatment of dyslipidemia, cessation of tobacco use, and antiplatelet therapy. This paper briefly reviews the most recent evidences about pharmacologic therapies in high-risk patients, focusing on benefits related to improvement of cardiovascular risk factors in hypertensive patients with chronic kidney disease.

Mild renal insufficiency is associated with reduced coronary flow in patients with non-obstructive coronary artery disease

Patients with chronic kidney disease (CKD) have increased risk for cardiovascular events. However, the association between these pathophysiological processes is unclear. Therefore, this study was designed to determine the association between early CKD and coronary microvascular disease in patients with normal or mildly diseased coronary arteries. A total of 605 patients with normal or mildly diseased coronary arteries based on angiography underwent coronary flow reserve (CFR) evaluation using intracoronary adenosine. Patients were divided based on glomerular filtration rate (GFR). CKD was defined as calculated GFR<60 ml/min/1.73 m(2). Patients with normal GFR (> or =60 ml/min/1.73 m(2), n=481) had higher CFR compared to those with CKD (n=124, CFR=3.0+/-0.8 vs 2.6+/-0.6, P<0.001, respectively). Patients with abnormal GFR were more likely to be older and of female gender, with greater prevalence of hypertension. Multiple logistic regression analysis adjusted for the aforementioned risk factors further supported the observed relationship. The current study shows that reduced renal function is associated with attenuated coronary vasodilator capacity in patients without obstructive coronary artery disease. The correlation between low GFR and reduced CFR may suggest parallel alterations in the renal and coronary microcirculation at the early stage of disease. Impairment in both microcirculatory beds may reflect an unmeasured risk factor induced by blunted renal function and add a burden to the increased propensity for cardiovascular events in CKD.

Left ventricular hypertrophy in normoalbuminuric type 2 diabetic patients not taking antihypertensive treatment

BACKGROUND

Left ventricular hypertrophy (LVH) is an independent risk factor for myocardial ischaemia, cardiac arrhythmia, sudden death, and heart failure, all common findings in patients with type 2 diabetes.

AIM

To determine the prevalence of, and risk factors for, LVH in normoalbuminuric type 2 diabetic patients not taking antihypertensive treatment.

DESIGN

Cross-sectional study.

METHODS

From 1994 to 1998, M-mode echocardiography was performed by one experienced examiner in 262 consecutive, normoalbuminuric Caucasian type 2 diabetic patients, all with blood pressure <160/95 mmHg and not taking antihypertensive medication. Mean +/- SD age was 54 +/- 10 years, 109 were women, and median known duration of diabetes was 4 (range 1-28) years. Body mass index (BMI) was 28 +/- 5 kg/m(2), and blood pressure 134 +/- 13/79 +/- 8 mmHg, all means +/- SD. Median urinary albumin excretion rate was 9 (range 2-30) mg/24 h.

RESULTS

The prevalence of LVH indexed to height(2.7) was 43% (95%CI 38-50%), and was similar in men and women. BMI, HbA(1c) and log urinary albumin excretion were significantly associated with left ventricular hypertrophy in a logistic regression model, whereas sex, age, known duration of diabetes and blood pressure were not. Similar results were obtained for left ventricular mass index.

DISCUSSION

LVH was frequent in our normoalbuminuric type 2 diabetic patients not taking antihypertensive treatment. Several potentially modifiable risk factors, such as raised BMI, poor glycaemic control and elevated urinary albumin excretion rate, were associated with LVH.

Estimation of renal function in subjects with normal serum creatinine levels: influence of age and body mass index

BACKGROUND

The Cockcroft-Gault (CG) and simplified Modification of Diet in Renal Disease (MDRD) formulas are the most widely used estimates of renal function. The influence of age and body mass index (BMI) on the performance of these equations was analyzed in 850 subjects with serum creatinine levels less than 1.5 mg/dL (<133 micromol/L).

METHODS

Glomerular filtration rate (GFR) was measured as urinary clearance of continuously infused technetium Tc 99m-labeled diethylene triaminopentaacetic acid. Performance was assessed as bias, precision, and accuracy.

RESULTS

In the total population, the CG and MDRD calculations based on enzymatic measurement of serum creatinine (which is constantly less than that obtained by using the alkaline picrate [Jaffé] method) significantly underestimated GFR by 4.9 and 12.4 mL/min/1.73 m2 (0.08 and 0.21 mL/s/1.73 m2), respectively. In patients 65 years and older, underestimation by means of the CG formula was enhanced, whereas that by means of the MDRD formula was blunted, compared with the group younger than 65 years (-11.3 versus -3.7 mL/min/1.73 m2 [-0.19 versus -0.06 mL/s/1.73 m2] for CG and -3.7 versus -14.0 mL/min/1.73 m2 [-0.06 versus -0.23 mL/s/1.73 m2] for MDRD). GFR was underestimated to a large extent by means of the MDRD equation irrespective of BMI. Conversely, the underestimation by means of the CG formula found in lean people (-13.0 mL/min/1.73 m2 [-0.22 mL/s/1.73 m2]) was blunted in overweight people (BMI, 25 to 30 kg/m2) and reversed to overestimation (+10.1 mL/min/1.73 m2 [+0.17 mL/s/1.73 m2]) in obese subjects (BMI > 30 kg/m2).

CONCLUSION

As suggested by estimations obtained using enzymatic serum creatinine measurement, the MDRD equation may be the estimation of choice in elderly patients, whereas the CG estimate is preferable in subjects younger than 65 years. Nevertheless, when obesity is present, no reliable estimation can be obtained by using the CG or MDRD formula.

Minor abnormalities of renal function: a situation requiring integrated management of cardiovascular risk

Changes in renal function related with essential hypertension are associated with an elevated cardiovascular morbidity and mortality. Indices of altered renal function (e.g. microalbuminuria, increased serum creatinine concentrations, decrease in estimated creatinine clearance or overt proteinuria) are independent predictors of cardiovascular morbidity and mortality. The Framingham Heart Study documented the relevance of proteinuria for cardiovascular prognosis in the community. The Intervention as a Goal in Hypertension Treatment (INSIGHT) Study assessed the role of proteinuria as a very powerful risk factor. It has also been shown that microalbuminuria along with primary hypertension poses a high risk for cardiovascular diseases. Recent data indicate that even minor derangements of renal function are associated with the clustering of cardiovascular risk factors observed in metabolic syndrome, that promote progression of atherosclerosis. All these parameters should be routinely evaluated in clinical practice, and considered in any stratification of cardiovascular risk in hypertensive patients. The high prevalence of chronic kidney disease in the general and in the hypertensive populations implies the need for an integrative therapeutic approach to fully protect renal and cardiovascular systems simultaneously.

Determinants of cardiorenal damage progression in normotensive and never-treated hypertensive subjects

BACKGROUND

In the present longitudinal study, we attempted to identify the determinants of cardiorenal damage progression in normotensive subjects (<140/90 mm Hg) and patients with never-treated essential hypertension.

METHODS

Renal hemodynamics and function and cardiac morphology were evaluated by isotopic techniques and echocardiography at baseline and after a median follow-up period of 5.2 years (range 3 to 13) in 30 normotensive and 33 hypertensive subjects.

RESULTS

The results are mean +/- SD. Among normotensive subjects at baseline, 50% became hypertensive during follow-up. In the whole population, multivariate analysis showed that age was the main determinant of the progression of systolic blood pressure. The yearly change in glomerular filtration rate (GFR) was exaggerated in hypertensive when compared to normotensive subjects at baseline (-1.22 +/- 2.71 vs. 0.12 +/- 2.08 mL/min/year, respectively) (P= 0.033). In the whole population, only baseline systolic blood pressure remained correlated to the change in GFR, independently of GFR at baseline (model r(2)= 0.44) (P < 0.0001). The observed increase in albuminuria was correlated with change in blood pressure only in hypertensive subjects at baseline. Left ventricular mass (LVM) progression was significant only in men and its determinants were basal plasma aldosterone, serum uric acid, and triglyceride and change in systolic blood pressure (r(2)= 0.71) (P < 0.0001).

CONCLUSION

In a population of untreated subjects, baseline blood pressure as well as progression of blood pressure during follow-up are the main determinants of the decline in GFR, progression of albuminuria, and LVM.

Elevated Pulse Pressure Is Associated With Low Renal Function in Elderly Patients With Isolated Systolic Hypertension

In the past decade, pulse pressure has emerged as a strong predictor of cardiovascular morbidity and mortality. During aging, elevation of pulse pressure is a consequence of stiffening of the arterial wall. The relationship between pulse pressure and the renal aging process was studied in a cohort of 212 patients with never-treated isolated systolic hypertension. Glomerular filtration rate and effective renal plasma flow were measured using constant infusion of technetium 99m ( 99m Tc)-DTPA and 131 I-ortho-iodohippurate, respectively, and timed urine collections. The relationship between pulse pressure and renal function was studied using a linear regression model in the total population and in 40 to 49, 50 to 59, and 60 years and older age categories. In the whole population, there was an inverse relationship between pulse pressure and glomerular filtration rate; however, this relation did not persist after adjustment for age. In fact, the inverse relationship between pulse pressure and glomerular filtration rate was only present in patients 60 years of age or older. This relationship in elderly patients remained after adjustment for age, gender, MAP, and cardiovascular risk factors ( P =0.006). It is suggested that pulse pressure, a marker of arterial stiffening, may have a detrimental influence on the age-related decline in glomerular filtration rate, after 60 years of age in patients with never-treated isolated systolic hypertension.

Development of chronic kidney disease in essential hypertension during long-term therapy

PURPOSE OF REVIEW

This review examines the relevance of the development of chronic kidney disease in long-term hypertensive patients on the cardiovascular prognosis.

RECENT FINDINGS

Recently published guidelines recognize the relevance of the development of chronic kidney disease in the stratification of risk for the hypertensive patient. An adequate assessment of renal function, including an estimation of the glomerular filtration rate, is mandatory in order to ensure an adequate evaluation of the global cardiovascular risk in the hypertensive patient. The presence of subtle elevations in serum creatinine concentrations is a potent predictor of a poor cardiovascular prognosis. The clustering of associated risk factors seems to justify the elevated cardiovascular risk observed in patients with essential hypertension and mild renal function derangement.

SUMMARY

Chronic kidney disease is associated with a significant increase in cardiovascular risk attributable to the simultaneous existence of other risk factors related to the metabolic syndrome. The high prevalence of chronic kidney disease in the general and hypertensive populations forces the recognition of its relevance and the need for an integrated therapeutic approach simultaneously to protect the renal and cardiovascular systems fully.

Endothelial Dysfunction and Mild Renal Insufficiency in Essential Hypertension

Background— Mild to moderate renal insufficiency in individuals with essential hypertension is currently considered the expression of a renal microvasculopathy characterized by preglomerular arteriolar involvement and tubulo-interstitial changes. Whether endothelial dysfunction plays a role in this alteration is still undefined.

Methods and Results— We investigated the relationship between endothelial function (hemodynamic response to acetylcholine [ACh] in the forearm) and renal function in 500 patients with uncomplicated, never-treated, essential hypertension and serum creatinine within the normal range (ie, ≤1.5 mg/dL). Serum creatinine, creatinine clearance, and estimated glomerular filtration rate (GFR, by the Modification of Diet in Renal Disease formula) were related to the forearm blood flow response to ACh (all P ≤0.003), and these relationships held true in multiple regression analyses that included age, gender, systolic pressure, serum cholesterol and glucose, smoking, and body mass index. Accordingly, on multiple logistic regression analysis, the risk of moderate renal dysfunction (ie, an estimated GFR <60 mL · min −1 · 1.73 m −2 ) was 64% lower (OR 0.36, 95% CI 0.18 to 0.70) in patients in the third ACh tertile (ie, those showing the higher vasodilatory response) than in those in the first tertile (ie, showing the lower response). C-reactive protein was related directly to serum creatinine and inversely to GFR and vasodilatory response to ACh, which suggests that endothelial dysfunction is a possible mechanism linking inflammation and impaired renal function in essential hypertension.

Conclusions— An impaired vasodilatory response to ACh appears to be associated with renal function loss in patients with essential hypertension. This association suggests that systemic endothelial dysfunction is involved in mild to moderate renal insufficiency in patients with uncomplicated essential hypertension.

Relevancia de la insuficiencia renal en el pronóstico cardiovascular de los pacientes con hipertensión arterial esencial

Recently published guidelines recognize the relevance of the finding of chronic kidney disease in the stratification of risk of the hypertensive patient. Determination of the presence of microalbuminuria and estimation of glomerular filtration rate are mandatory in order to ensure an adequate evaluation of global cardiovascular risks in the hypertensive patient. The presence of subtle elevations of serum creatinine concentrations and/or proteinuria are also potent predictors of a poor cardiovascular prognosis. Clustering of associated risk factors seems to justify the elevated cardiovascular risk observed in patients with essential hypertension and mild alterations of renal function.

Heterogeneity of Cardiorenal Characteristics in Normotensive Subjects

Blood pressure is a marker of elevated risk for cardiovascular disease, even within the normotensive range. The present study evaluates cardiorenal modifications observed in normotensive (<140/90 mm Hg) subjects. Using World Health Organization–International Society of Hypertension definitions, 265 normotensive subjects were categorized as having optimal (n=73), normal (n=84), and high-normal (n=108) blood pressure. Renal hemodynamics and function and cardiac morphology were evaluated by isotopic clearance techniques and ultrasonography, respectively. Urinary albumin excretion was measured in 24-hour urine collections. Body mass index and 24-hour urinary sodium (estimate of sodium intake), as well as left ventricular mass index, relative wall thickness, and glomerular filtration rate and filtration fraction, progressively increased in the optimal to high-normal groups. In contrast, effective renal plasma flow remained constant. Albuminuria was similar in all groups. Of interest, the proportion of subjects with concentric pattern of cardiac geometry (relative wall thickness ≥0.44) increased from 7% in optimal to 13% and 20% in normal and high-normal groups, respectively ( P <0.05). Within this normotensive range of blood pressure, left ventricular mass index and relative wall thickness but not albuminuria were linearly correlated to systolic blood pressure; however, no correlation with diastolic blood pressure was found. In conclusion, changes in cardiac geometry and renal hemodynamics (increase in glomerular filtration rate and filtration fraction, an approximate index of glomerular pressure) that could predispose to cardiovascular morbidity and renal risk are already present in normotensive subjects with blood pressure higher than 120/80 mm Hg.