Microalbuminuria in patients with previous myocardial infarction

Association between normal or mildly reduced kidney function, cardiovascular risk and biomarkers for atherosclerosis: results from the ENCORE trial

Background

Moderate-to-severe kidney dysfunction is associated with atherosclerotic cardiovascular disease (ASCVD). Gradations of normal or mildly reduced kidney function may also associate with ASCVD risk.

Methods

We conducted a secondary analysis using baseline data from the Exercise and Nutritional Interventions for Cardiovascular Health (ENCORE) trial. Participants were sedentary, overweight and obese adults with unmedicated pre-hypertension or Stage I hypertension and an estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m². The Pooled Cohorts Equations were used to estimate a 10-year risk for first ASCVD event. Carotid artery intima-media thickness (IMT) and brachial artery flow-mediated dilation (FMD) were measured to assess subclinical atherosclerosis and vascular endothelial function, respectively. Using linear regression, we examined the association between eGFR and ASCVD risk, IMT and FMD.

Results

Participants (N = 139) were predominantly women (65%), white (60%), with a mean age of 52.0 ± 9.6 years and mean eGFR of 89.1 ± 15.0 mL/min/1.73 m². Lower eGFR of 15 mL/min/1.73 m² was associated with higher ASCVD risk [b = −2.7% (95% confidence interval: −3.7, −1.8%), P < 0.001], higher IMT [b = 0.05 mm (0.03, 0.08 mm), P < 0.001] and lower FMD [b = −0.87% (−1.64, −0.11%), P = 0.026]. Compared with eGFR ≥90 mL/min/1.73 m², those with eGFR 60–89 mL/min/1.73 m² had higher mean ASCVD risk (7.6% versus 2.7%; P < 0.001), greater mean IMT (0.74 mm versus 0.66 mm; P < 0.001) and lower mean FMD (2.0% versus 3.7%; P = 0.026). After controlling for CVD risk factors, the association between eGFR and IMT remained significant (P < 0.001), and eGFR and FMD trended toward significance (P = 0.08).

Conclusions

Among overweight and obese adults with unmedicated high blood pressure and eGFR ≥60 mL/min/1.73 m², lower eGFR is associated with a greater 10-year risk for first ASCVD event, higher IMT and relatively impaired FMD.

Echogenicity of the carotid intima-media complex and cardiovascular risk factors

INTRODUCTION

Increased carotid intima-media thickness (IMT) has been associated with increased risk of myocardial infarction (MI) and stroke. A measure of echogenicity, the grey scale median (GSM), has been shown to be inversely correlated with cardiovascular risk factors and to be predictive of mortality in a community-based cohort. We assessed the factors associated with carotid IM-GSM in younger, non-diabetic patients with a recent MI.

METHODS AND RESULTS

A total of 122 patients (women, 25%) aged 31-80 years (61) were recruited 2-3 days after an acute MI. Ultrasound examinations of the carotid arteries were performed 1-12 months after the MI. IMT was 0·78 (SD 0·17) mm on the right side and 0·81 (0·20) mm on the left side (P = 0·05). GSM was 88·60 (range 46-132, SD 18·32) on the right side and 82·10 (40-126, 17·89) on the left side (P = 0·002). Triglycerides (TG) correlated with GSM on both sides (right, r = -0·27, P = 0·003; left, r = -0·18, P = 0·05). On the right side, GSM was 92·15 and 82·26 (P = 0·05) in patients with TG < and ≥1·7, and on the left side, it was 84·04 and 74·55 (P = 0·02) in patients with TG < and ≥2·3. On multivariate analysis, TG were significantly associated with GSM, both on the right side (P = 0·01) and on the left side (P = 0·009).

CONCLUSION

We found a negative association between TG and carotid IM-GSM on both sides in patients with a recent MI. Our results also suggest that atherosclerosis progression may be faster on the left side in patients with coronary heart disease.

Urinary Smad1 is a novel marker to predict later onset of mesangial matrix expansion in diabetic nephropathy

OBJECTIVE

We reported that Smad1 is a key transcriptional factor for mesangial matrix expansion in diabetic nephropathy. In this study, we examined whether urinary Smad1 in an early phase of diabetes can predict later development of glomerulosclerosis in diabetic nephropathy and how an angiotensin II type 1 receptor blocker (ARB) can modulate structural changes and urinary markers.

RESEARCH DESIGN AND METHODS

Smad1 and albumin in the urine were examined 4 weeks after injection of streptozotocin in 48 rats or 6 weeks of diabetes in db/db mice. Their renal pathology was analyzed after 20 weeks in rats or 12 weeks in mice. Among 48 diabetic rats 7 rats were treated with olmesartan for 20 weeks.

RESULTS

Urinary Smad1 of diabetic rats at 4 weeks was nicely correlated with mesangial matrix expansion at 24 weeks (r = 0.70, P < 0.001), while albuminuria showed a weaker association (r = 0.31, P = 0.043). Olmesartan treatment significantly ameliorated glomerulosclerosis and dramatically decreased urinary Smad1 (from 3.9 +/- 2.9 to 0.3 +/- 0.3 ng/mg creatinine, P < 0.05). In db/db mice, urinary Smad1 at 6 weeks was also significantly correlated with mesangial expansion at 18 weeks. In contrast, there was no change in urinary Smad1 in control diabetic rats or mice.

CONCLUSIONS

The increase of urinary Smad1 in the early stages of diabetes is correlated with later development of glomerulosclerosis in two rodent models. These data indicate that urinary Smad1 could be a novel predictor for later onset of morphological changes and can be used to monitor the effect of ARBs in diabetic nephropathy.

Renin angiotensin system blockade and cardiovascular outcomes in patients with chronic kidney disease and proteinuria: a meta-analysis

OBJECTIVE

The role of renin angiotensin system (RAS) blockade in controlling hypertension and the positive impact on cardiovascular (CV) outcomes is well known. However, the role of RAS blockade in improving CV outcomes in patients with chronic kidney disease (CKD) is still unclear.

METHODS

Randomized controlled trials that analyzed CV outcomes in patients with CKD/proteinuria treated with RAS blockade (angiotensin-converting enzyme inhibitors/angiotensin receptor blockers) were included in our study. The relative risk across all study groups was computed using Mantel-Hanszel random effects model. Results were calculated with 95% CI and was considered statistically significant if 2-sided alpha error was <.05. Renin angiotensin system blockade-based therapy was compared with placebo and control (beta-blocker, calcium-channel blockers and other antihypertensive-based therapy) therapy in the study.

RESULTS

Twenty-five trials (N = 45758) were used for analysis. Renin angiotensin system blockade decreased the risk for heart failure in patients with diabetic nephropathy when compared with placebo 0.78 (95% CI 0.66-0.92, P = .003) and control therapy (0.63, 95% CI 0.47-0.86, P = .003). The risk for CV outcomes was decreased with RAS blockade (0.56, 95% CI 0.47-0.67, P < .001) in nondiabetic nephropathy patients with CKD when compared with control therapy. There was also a significant reduction of CV outcomes (0.84, 95% CI 0.78-0.91, P < .0001), myocardial infarction (0.78, 95% CI 0.65-0.97, P = .03), and heart failure (0.74, 95% CI 0.58-0.95, P = .02) when we pooled all the patients with CKD and compared RAS blockade to placebo.

CONCLUSIONS

A pooled analysis of all causes of CKD revealed a reduction in the risk for myocardial infarction, heart failure, and total CV outcomes when RAS blockade was compared with placebo. RAS blockade decreases the risk for CV outcomes and heart failure when compared with control therapy in patients with proteinuria. There were also benefits with RAS blockade in reducing the risk of CV outcomes and heart failure in patients with diabetic nephropathy when compared with placebo.

Novel links between the long pentraxin 3, endothelial dysfunction, and albuminuria in early and advanced chronic kidney disease

BACKGROUND AND OBJECTIVES

Albuminuria and inflammation predict cardiovascular events. Pentraxin 3, an inflammatory mediator produced by, among others, endothelial cells, may have a role in atherogenesis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In 207 Swedish patients with stage 5 chronic kidney disease and 79 Turkish patients with type 2 diabetes and proteinuria and normal renal function, whether serum pentraxin 3 levels are associated with albuminuria and endothelial dysfunction was studied.

RESULTS

Patients with stage 5 chronic kidney disease and a high degree of albuminuria more often had diabetes and higher levels of pentraxin 3, vascular cellular adhesion molecule-1, and blood pressure. Moreover, pentraxin 3 was independently associated with 24-h urinary albumin excretion. In patients with type 2 diabetes, pentraxin 3 was significantly higher than in control subjects. Patients with type 2 diabetes and more proteinuria had higher pentraxin 3, C-reactive protein, glycosylated hemoglobin, insulin, and homeostasis model assessment index as well as lower flow-mediated dilation and serum albumin. Pentraxin 3 was positively correlated with C-reactive protein, homeostasis model assessment index, and carotid intima-media thickness and negatively with flow-mediated dilation. Pentraxin 3 and glomerular filtration rate were independently associated with 24-h urinary protein excretion. Only pentraxin 3 and proteinuria were significantly and independently associated with flow-mediated dilation.

CONCLUSIONS

In two different renal cohorts, one of stage 5 chronic kidney disease and one of type 2 diabetes and normal renal function, pentraxin 3 was independently associated with proteinuria. Moreover, both pentraxin 3 and proteinuria were associated with endothelial dysfunction in patients with type 2 diabetes.

Time to abandon microalbuminuria?

The term microalbuminuria--a urinary albumin excretion (UAE) between 20 and 200 microg/min--has been introduced to identify subjects at increased risk of renal and cardiovascular disease. However, the relationship between albuminuria and risk is not restricted to the microalbuminuric range and extends to as low as 2-5 microg/min. On the contrary, the increase of UAE above 200 microg/min (macroalbuminuria) heralds the onset of proteinuria (urinary protein excretion above 0.5 g/24 h) and progressive renal and cardiovascular disease. Albuminuria is a component of the metabolic syndrome and may represent a marker of the increased risk of renal and cardiovascular disease associated with insulin resistance and endothelial dysfunction. Proteinuria is a sign of established kidney damage and plays a direct pathogenic role in the progression of renal and cardiovascular disease. Albuminuria reflects functional and potentially reversible abnormalities initiated by glomerular hyperfiltration, proteinuria, a size-selective dysfunction of the glomerular barrier normally associated with glomerular filtration rate (GFR) decline that may result in end-stage renal disease. Thus, the limit of 200 microg/min segregates patients with albuminuria or proteinuria who are at quite different risk. Among subjects with albuminuria, however, there is a continuous relationship between albumin excretion and risk and no lower bound between normal albuminuria and microalbuminuria can be identified that segregates subjects at different risk. Thus, the terms microalbuminuria and macroalbuminuria could be replaced by the concepts of albuminuria- and proteinuria-associated diseases. Future studies are needed to identify levels of albuminuria below which therapy is no longer beneficial.

The relationship between flow-mediated dilatation and left ventricular function in type 2 diabetic patients with microalbuminuria

OBJECTIVE

The aim of this study was to assess the relationship between flow-mediated dilatation (FMD) and left ventricular (LV) systolic and diastolic function in type 2 diabetic patients with or without microalbuminuria.

RESEARCH DESIGN AND METHODS

We prospectively evaluated 68 consecutive patients (36 women, 32 men; mean age 57 +/- 11 yr) with type 2 diabetes mellitus (DM). Patients were divided into two groups according to whether or not they had microalbuminuria: group 1 (n = 29, mean age 58 +/- 10 yr) with microalbuminuria and group 2 (n = 39, mean age 56 +/- 10 yr) without microalbuminuria. LV function was assessed by classical methods and Doppler tissue imaging (DTI). Left ventricular ejection fraction (EF), interventricular (IVS) and posterior wall (PW) thickness, peak early (E) and late (A) transmitral filling velocities, their ratio (E/A) and deceleration time of the mitral E wave (DT), LV isovolumetric relaxation time (IVRT), flow propagation of velocity (Vp), and E/Vp were evaluated by conventional echocardiography. Early diastolic (Em), late diastolic (Am), and peak systolic (Sm) mitral annular velocities were measured. Em/Am and the ratio of early diastolic mitral inflow velocity to Em (E/Em), which is a reasonably good index for predicting elevated LV filling pressure, were calculated by DTI. Endothelial function, measured as flow-mediated dilatation of the brachial artery using ultrasound, was calculated in two groups.

RESULTS

FMD was lower in those with microalbuminuria than those without (8.8 +/- 6.44% vs 12.6 +/- 7.24%, p = 0.03). Group 1 had longer DT (223 +/- 39 ms vs 199 +/- 37 ms, p = 0.01) and longer IVRT (109 +/- 13 ms vs 100 +/- 13 ms, p = 0.03) than that of group 2 with conventional echocardiography. Group 1 had significantly lower Em/ Am (0.79 +/- 0.27 cm/s vs 1.02 +/- 0.44 cm/s, p = 0.01), lower Vp (40.4 +/- 9.98 vs 50.4 +/- 19.01 cm/s, p = 0.01) than that of group 2. Group 1 had significantly higher serum creatinine (1 +/- 0.33 mg/dL vs 0.7 +/- 0.19, p = 0.001). In logistic regression analysis, FMD was the only variable independently related to microalbuminuria. FMD was positively correlated with EF (r = 0.43, p = 0.02) and E/A (r = 0.40, p = 0.03), and negatively correlated with E/Em (r = 0.41, p = 0.04) and E/Vp (r = 0.41, p = 0.04) only in patients with microalbuminuria.

CONCLUSION

It was found that left ventricular diastolic function and FMD are impaired in type 2 diabetic patients with microalbuminuria. FMD may be related to LV diastolic dysfunction only in patients with microalbuminuria.