Role of Diminished Renal Function in Cardiovascular Mortality

Role of vasopressin and aldosterone in pulmonary arterial hypertension: A pilot study

Much has been learned about the pathophysiological state that underlies the development of increased total body volume and edema in left ventricular failure. Very little, however, is known about the mechanism underlying systemic hypervolemia in patients with isolated right ventricular dysfunction. In this manuscript, we describe our randomized clinical trial to assess the relationship between severity of pulmonary arterial hypertension and neurohormonal activation, total plasma volume and renal function. We assess the role of aldosterone and vasopressin in volume retention in patients with pulmonary arterial hypertension with right ventricular failure. As understanding of the pathogenesis of left ventricular failure has been associated with improved therapies, the better understanding of the mechanisms of isolated right ventricular cardiac failure will also lead to improved patient care.

Deficiency in Six2 during prenatal development is associated with reduced nephron number, chronic renal failure, and hypertension in Br/+ adult mice

The Br/+ mutant mouse displays decreased embryological expression of the homeobox transcription factor Six2, resulting in hertitable renal hypoplasia. The purpose of this study was to characterize the renal physiological consequences of embryonic haploinsuffiency of Six2 by analyzing renal morphology and function in the adult Br heterozygous mutant. Adult Br/+ kidneys weighed 50% less than those from wild-type mice and displayed glomerulopathy. Stereological analysis of renal glomeruli showed that Br/+ kidneys had an average of 88% fewer glomeruli than +/+ kidneys, whereas individual glomeruli in Br/+ mice maintained an average volume increase of 180% compared with normal nephrons. Immunostaining revealed increased levels of endothelin-1 (ET-1), endothelin receptors A (ET(A)) and B (ET(B)), and Na-K-ATPase were present in the dilated renal tubules of mutant mice. Physiological features of chronic renal failure (CRF) including elevated mean arterial pressure, increased plasma creatinine, and dilute urine excretion were measured in Br/+ mutant mice. Electron microscopy of the Br/+ glomeruli revealed pathological alterations such as hypercellularity, extracellular matrix accumulation, and a thick irregular glomerular basement membrane. These results indicate that adult Br/+ mice suffer from CRF associated with reduced nephron number and renal hypoplasia, as well as glomerulopathy. Defects are associated with embryological deficiencies of Six2, suggesting that proper levels of this protein during nephrogenesis are critical for normal glomerular development and adult renal function.

Prognostic implications of baroreflex sensitivity in heart failure patients in the beta-blocking era

OBJECTIVES

This study investigated the clinical correlates and prognostic value of depressed baroreceptor-heart rate reflex sensitivity (BRS) among patients with heart failure (HF), with and without beta-blockade.

BACKGROUND

Abnormalities in autonomic reflexes play an important role in the development and progression of HF. Few studies have assessed the effects of beta-blockers on BRS in HF.

METHODS

The study population consisted of 103 stable HF patients, age (median [interquartile range]) 54 years (48 to 57 years), with New York Heart Association (NYHA) functional class > or =III in 22, and with a left ventricular ejection fraction (LVEF) of 30% (24% to 36%), treated with beta-blockers; and 144 untreated patients, age 55 years (48 to 60 years), with NYHA functional class > or =III in 47%, and an LVEF of 26% (21% to 30%). They underwent BRS testing (phenylephrine technique).

RESULTS

In both treated and untreated patients, a lower BRS was associated with a higher (> or =III) NYHA functional class (p = 0.0002 and p < 0.0001, respectively); a more severe (> or =2) mitral regurgitation (p = 0.007 and p = 0.0002), respectively; a lower LVEF (p = 0.0004 and p = 0.001, respectively), baseline RR interval (p = 0.0004 and p = 0.0002, respectively), and SDNN (p < 0.0001, p = 0.002, respectively); and a higher blood urea nitrogen (p = 0.004, p < 0.0001, respectively). Clinical variables explained only 43% of BRS variability among treated and 36% among untreated patients. During a median follow-up of 29 months, 17 of 103 patients and 55 of 144 patients, respectively, experienced a cardiac event. A depressed BRS (<3.0 ms/mm Hg) was significantly associated with the outcome, independently of known risk predictors and beta-blocker treatment (adjusted hazard ratio: 3.0 [95% confidence interval: 1.5 to 5.9], p = 0.001).

CONCLUSIONS

Baroreceptor-heart rate reflex sensitivity does not simply mirror the pathophysiological substrate of HF. A depressed BRS conveys independent prognostic information that is not affected by the modification of autonomic dysfunction brought about by beta-blockade.

Incremental value of renal function in risk prediction with the Seattle Heart Failure Model

BACKGROUND

Impaired renal function portends poor heart failure (HF) outcomes. The Seattle Heart Failure Score (SHFS), a multimarker risk assessment tool, however does not incorporate renal function. In this study, we assessed the incremental value of renal function over the SHFS in patients with advanced HF on contemporary optimal treatment.

METHODS

Blood urea nitrogen (BUN), serum creatinine (sCr), BUN/sCr ratio, and estimated glomerular filtration rate were assessed in survival models with SHFS as the base model among 443 patients with HF (52 +/- 12 years, male 68.5%, white 52.4%, ejection fraction 0.18 +/- 0.08). Incremental value of renal function was assessed by changes in the likelihood ratio chi(2) and the area under the receiver operating characteristic curves for 1-, 2-, and 3-year event prediction.

RESULTS

During a median follow-up of 21 months, 108 (24.5%) of 443 patients had an event (death [n = 92], urgent transplantation [n = 13], or ventricular assist device implantation [n = 3]). All renal parameters individually were associated with outcome (BUN, P < .001; sCr, P < .001; BUN/sCr ratio, P = .006; and estimated glomerular filtration rate, P = .006); however, only BUN was an independent predictor of events in multivariable analyses. Addition of BUN improved the predictive ability of SHFS (Deltalikelihood ratio chi(2) 5.03, P = .025); however, the increase in the area under the receiver operating characteristic curve was marginal (year 1, 0.786 to 0.791; year 2, 0.732 to 0.741; year 3, 0.745 to 0.754; all P > .2).

CONCLUSION

Among the various renal function parameters, BUN had the strongest association with outcomes in patients with advanced HF. However, the incremental value of renal function over the SHFS for risk determination was marginal.

Role of vasopressin and vasopressin receptor antagonists in type I cardiorenal syndrome

The pathogenesis of cardiac failure involves activation of the neurohumoral axis including stimulation of the sympathetic nervous system, the renin-angiotensin-aldosterone, and nonosmotic vasopressin systems. While these responses are critical in maintaining arterial pressure, they are associated with renal vasoconstriction, as well as sodium and water retention. In advanced circumstances, renal dysfunction and hyponatremia occur with cardiac failure. Even a modest rise in serum creatinine related to diminished renal function in heart failure patients is associated with increased risk for cardiovascular morbidity and mortality. Similarly, increased thirst and the nonosmotic stimulation of vasopressin in advanced cardiac failure leads to hyponatremia, which is also a major risk factor for mortality. Currently, V2 vasopressin receptor antagonists have been shown to correct hyponatremia in cardiac failure. One such agent, conivaptan, also is a V1 receptor antagonist which could theoretically benefit heart failure patients by decreasing cardiac afterload and remodeling. The effect of V2 receptor antagonists to correct hyponatremia in heart failure patients appears to be quite safe. However, to date no effect on mortality has been demonstrated.

Relaxin, a pleiotropic vasodilator for the treatment of heart failure

Relaxin is a naturally occurring peptide hormone that plays a central role in the hemodynamic and renovascular adaptive changes that occur during pregnancy. Triggering similar changes could potentially be beneficial in the treatment of patients with heart failure. The effects of relaxin include the production of nitric oxide, inhibition of endothelin, inhibition of angiotensin II, production of VEGF, and production of matrix metalloproteinases. These effects lead to systemic and renal vasodilation, increased arterial compliance, and other vascular changes. The recognition of this has led to the study of relaxin for the treatment of heart failure. An initial pilot study has shown favorable hemodynamic effects in patients with heart failure, including reduction in ventricular filling pressures and increased cardiac output. The ongoing RELAX-AHF clinical program is designed to evaluate the effects of relaxin on the symptoms and outcomes in a large group of patients admitted to hospital for acute heart failure. This review will summarize both the biology of relaxin and the data supporting its potential efficacy in human heart failure.

The relationship between renal function and outcome from heart valve surgery

BACKGROUND

The prognostic importance of renal function in patients undergoing surgery for valvular heart disease is poorly defined. The current study addresses this issue.

METHODS

Baseline demographic and clinical variables, including the European system for cardiac operative risk evaluation (EuroSCORE), were recorded prospectively from 514 consecutive patients undergoing heart valve surgery between April 2000 and March 2004. Patients with active infective endocarditis and/or requiring emergency surgery were excluded. The glomerular filtration rate was estimated (eGFR) using the Modification of Diet in Renal Disease equation. The primary outcome was all-cause mortality.

RESULTS

During a median follow-up of 2 years, 87 patients died. In univariable analysis, both eGFR (hazard ratio [HR] 0.69 per 10 mL/min per 1.73 m2, P<.001) and creatinine (HR 1.04 per 10 micromol/L, P<.001) predicted mortality. Estimated GFR was a stronger predictor and was used in subsequent multivariable models. It remained a powerful independent predictor of death in a multivariable model including all study variables (HR 0.70 per 10 mL/min per 1.73 m2 increase, P<.001) and in a model including EuroSCORE (HR 0.64 per 10 mL/min per 1.73 m2 increase, P<.001). After correction for preoperative EuroSCORE, an eGFR of <60 mL/min per 1.73 m2 was associated with an excess hazard of death of 2.31 (P=.001).

CONCLUSION

Renal function, particularly the eGFR, is a powerful predictor of outcome in patients undergoing heart valve surgery. This prognostic utility is independent of other recognized risk factors and the EuroSCORE.

Cardiovascular events and all-cause mortality by albuminuria and decreased glomerular filtration rate in patients with vascular disease

OBJECTIVES

Albuminuria and decreased estimated glomerular filtration rate (eGFR) are associated with increased cardiovascular risk, but do not necessarily coexist and have different pathophysiological mechanisms. This study aims to evaluate separate and combined effects of decreased eGFR and albuminuria on the occurrence of vascular diseases and mortality in patients with vascular disease.

DESIGN

Prospective cohort study.

SETTING

University Medical Center Utrecht, the Netherlands.

SUBJECTS AND MAIN OUTCOME MEASURES

2600 patients with vascular disease were followed for vascular events, vascular and all-cause mortality. Cox regression analysis was used to calculate hazard ratios (HRs) according to eGFR (MDRD) and albuminuria (albumin-to-creatinine ratio >3 mg mmol(-1)).

RESULTS

In this population, 14.0% had albuminuria, 15.6% had eGFR <60 ml min(-1) 1.73 m(-2) and 5.2% had both. Nonalbuminuric decreased eGFR and albuminuria with normal eGFR generated moderately increased risks on all outcomes. eGFR <60 ml min(-1) 1.73 m(-2) without albuminuria mainly influenced the risk of vascular events (HR 1.50; 1.05-2.15) whilst albuminuria with eGFR >or=60 ml min(-1) 1.73 m(-2) principally affected all-cause mortality (HR 1.53; 1.04-2.26). The combination of eGFR <60 ml min(-1) 1.73 m(-2) and albuminuria was associated with an increased risk for vascular events (HR 2.27; 1.54-3.34), vascular mortality (HR 2.22; 1.40-3.52) and all-cause mortality (HR 1.84; 1.25-2.69). Comparable results were found in additional analyses amongst 759 diabetic patients.

CONCLUSIONS

The combination of decreased eGFR with albuminuria is associated with the highest risks of vascular events, vascular and all-cause mortality in patients with vascular diseases. To adequately estimate vascular risk associated with impaired renal function, both eGFR and urinary albumin should be considered.

Pulmonary hypertension, right ventricular failure, and kidney: different from left ventricular failure?

In this article, the pathophysiology of left ventricular failure is reviewed. By contrast, the paucity of information about pulmonary arterial hypertension and right ventricular failure is acknowledged. The potential mechanisms whereby renal sodium and water retention in right ventricular failure secondary to pulmonary arterial hypertension can occur, despite normal left ventricular function, are discussed. With right ventricular failure as the primary cause of death in patients with pulmonary hypertension, more information about the mechanisms of renal sodium and water retention in these patients is direly needed. Specifically, studies to examine the activation of the neurohumoral axis at various stages of pulmonary arterial hypertension and right ventricular failure, including inhibition of mineralocorticoid and V2 vasopressin receptors, are indicated.

Non-invasive detection of ischemic left ventricular dysfunction using rest gated SPECT: expectation of simultaneous evaluation of both myocardial perfusion and wall motion abnormality

OBJECTIVE

Although the accurate detection of ischemic etiology is important in the management of patients with severe left ventricular (LV) dysfunction, it is difficult to determine using a non-invasive strategy. The present study investigates whether perfusion and regional functional abnormalities identified by quantitative electrocardiographic gated single-photon emission computed tomography (QGS) at rest can detect ischemic LV dysfunction in patients with severe LV dysfunction.

METHODS

Rest QGS with (99m)Tc-tetrofosmin was performed on 54 consecutive patients with LV ejection fraction of </=40%. Ischemic LV dysfunction (n = 32) was defined according to the established standard. Regional perfusion and wall motion were calculated using a 14-segment model (six mid-ventricular and eight apical segments) and compared with a normal control group.

RESULTS

The numbers of reduced [mean -1 standard deviation (SD) of normal individuals] and severely reduced (mean -2 SD) wall motion segments were similar between patients with ischemic and non-ischemic LV dysfunction (13.5 +/- 1.1 vs. 13.6 +/- 0.9 and 10.6 +/- 2.0 vs. 9.9 +/- 3.0 segments, respectively). The number of hypoperfused (mean -1 SD) segments was significantly greater in patients with ischemic LV dysfunction than in those with non-ischemic LV dysfunction (9.3 +/- 3.8 vs. 2.0 +/- 2.8 segments, P < 0.0001). The analysis of the receiver operating characteristics showed that a cut-off value of 4 hypoperfused segments among 14 segments provided the best separation between ischemic and non-ischemic LV dysfunction (sensitivity = 88% and specificity = 91%). Furthermore, patients with non-ischemic LV dysfunction had no severely hypoperfused (mean -2 SD) segments in any of the segments, whereas patients with ischemic LV dysfunction had 4.4 +/- 0.2 segments.

CONCLUSIONS

The QGS strategy at rest can accurately differentiate patients with ischemic LV dysfunction from those with severe LV dysfunction by simultaneous regional evaluation of wall motion and myocardial perfusion.

Admission or Changes in Renal Function During Hospitalization for Worsening Heart Failure Predict Postdischarge Survival

Background— Admission measures of renal function (blood urea nitrogen [BUN], estimated glomerular filtration rate [eGFR]) in patients hospitalized for worsening heart failure are predictors of in-hospital outcomes. Less is known about the changes and relationships among these variables and the postdischarge survival rate.

Methods and Results— In a retrospective analysis of 949 patients from the Outcomes of a Prospective Trial of Intravenous Milrinone for Exacerbations of Chronic Heart Failure, we investigated the relation between admission values and changes in BUN and eGFR and rate of death by 60 days after discharge. On admission, median eGFR was 51 mL � min −1 � 1.73 m −2 (interquartile range, 37 to 70 mL � min −1 � 1.73 m −2 ), and BUN was 25 mg/dL (interquartile range, 17 to 41 mg/dL). On average, there was a 1.1–mL � min −1 � 1.73 m −2 decrease in eGFR and a 4.7-mg/dL increase in BUN from admission to discharge. By discharge, 12% of patients had a >25% decrease in eGFR, and 39% had a >25% increase in BUN. Although both lower admission eGFR and higher admission BUN were associated with higher risk of death by 60 days after discharge, multivariable-adjusted Cox proportional-hazards analysis showed that BUN was a stronger predictor of death by 60 days than was eGFR (χ 2 , 11.6 and 0.6 for BUN and eGFR, respectively). Independently of admission values, an increase of ≥10 mg/dL in BUN during hospitalization was associated with worse 60-day survival rate: BUN (per 5-mg/dL increase) had a hazard ratio of 1.08 (95% CI, 1.01 to 1.16). Although milrinone treatment led to a minor improvement in renal function by discharge, the 60-day death and readmission rates were similar between the milrinone and placebo groups.

Conclusions— A substantial number of patients admitted with heart failure have worsening renal function during hospitalization. Higher admission BUN and increasing BUN during hospitalization, independently of admission values, are associated with a worse survival rate. Use of milrinone in these high-risk patients does not improve outcomes despite minor improvements in the renal function.

[Acute renal function deterioration in a Coronary Unit in Spain]

OBJECTIVE

To assess the incidence and prognostic value of acute renal function deterioration (ARFD) in patients with acute heart disease.

SETTING

Coronary Care Unit in a tertiary university hospital.

DESIGN

Retrospective study.

PARTICIPANTS

One hundred consecutive patients admitted during 2004.

INTERVENTIONS

No randomized interventions were done. Diagnostic and therapeutic procedures were performed according to local protocols and current Clinical Practice Guidelines. PRIMARY VARIABLES: The primary aim of the study was to analyze the incidence of acute renal function deterioration and its effect in mortality during hospitalization. ARFD was defined as the increase of serum creatinine by 0.5 mg/dl and/or by 50% over baseline.

RESULTS

Incidence of ARFD was 26%, with a mean increase of serum creatinine of 1.5 +/- 0.9 mg/dl. ARFD was significantly associated with age, background of hypertension and chronic kidney disease. Patients with ARFD had a more complicated course, longer hospitalizations, and received fewer catheterisms. Acute renal function deterioration was associated with higher mortality during hospitalization (33% versus 6%, p = 0.002).

CONCLUSIONS

Acute renal function deterioration is frequent in patients with acute heart disease and its presence is linked with higher mortality.

Contemporary trends in the pharmacological and extracorporeal management of heart failure: a nephrologic perspective

Heart failure and chronic kidney disease share a number of risk factors and pathophysiological pathways. These 2 pathological processes coexist in large numbers of patients. Whereas the presence of chronic kidney disease in patients with heart failure adversely influences their survival, cardiovascular disease is the major cause of mortality in individuals with chronic kidney disease. The management of heart failure by cardiologists has recently expanded from pharmacological treatment to extracorporeal strategies; the interaction between (and concurrent use of) these approaches traditionally has been part of nephrology care and training. The purpose of this review is to explore these management strategies from a nephrologic standpoint and cover the pathophysiology of diuretic resistance, new pharmaceutical strategies to induce natriuresis or aquaresis, and the physiological basis and theoretical advantages of fluid removal by nontraditional peritoneal or hemofiltration approaches. This review also focuses on the technical features, safety, and potential risks of dedicated ultrafiltration devices that do not require dialysis staff or facilities and that are now readily available to nonnephrologists.

Cystatin C concentration as a predictor of systolic and diastolic heart failure

BACKGROUND

Risk factors for heart failure (HF) may differ according to ejection fraction (EF). Higher cystatin C, a marker of kidney dysfunction, is associated with incident HF, but previous studies did not determine EF at diagnosis. We hypothesized that kidney dysfunction would predict diastolic HF (DHF) better than systolic HF (SHF) in the Cardiovascular Health Study.

METHODS AND RESULTS

Cystatin C was measured in 4453 participants without HF at baseline. Incident HF was categorized as DHF (EF > or = 50%) or SHF (EF < 50%). We compared the association of cystatin C with the risk for DHF and SHF, after adjustment for age, sex, race, medications, and HF risk factors. During 8 years of follow-up, 167 participants developed DHF and 206 participants developed SHF. After adjustment, sequentially higher quartiles of cystatin C were associated with risk for SHF (competing risks hazard ratios 1.0 [reference], 1.99 [95% confidence interval 1.14-3.48], 2.32 [1.32-4.07], 3.17 [1.82-5.50], P for trend < .001). The risk for DHF was apparent only at the highest cystatin C quartile (hazard ratios 1.0 [reference], 1.09 [0.62-1.89], 1.08 [0.61-1.93], and 1.83 [1.07-3.11]).

CONCLUSIONS

Cystatin C levels are linearly associated with the incidence of systolic HF, whereas only the highest concentrations of cystatin C predict diastolic HF.

Prognostic markers in heart failure--congestion, neurohormones, and the cardiorenal syndrome

There are several markers of poor prognosis in heart failure (HF). The most established markers of poor prognosis in HF include neurohormonal (NH) imbalance, low ejection fraction (EF), ventricular arrhythmias, intraventricular conduction delays, low functional capacity, low SBP, and renal failure. The relative importance of these factors is unknown, as they have never been studied together. We present a 74-year-old female with nonischemic cardiomyopathy and an EF<20% who over 24 years since diagnosis, never developed clinical or hemodynamic congestion, was never hospitalized for HF, and never required a loop diuretic. She had all of the clinical indicators of poor prognosis in HF except for severe NH imbalance and renal failure, illustrating their importance in HF prognosis. While NH activation in HF is initially an adaptive mechanism, an imbalance of NH effectors causes congestion leading to a vicious cycle of congestion, renal dysfunction, and worsening of HF. The combination of NH activation and renal failure in HF is a vasomotor nephropathy known as the cardiorenal syndrome (CRS) and portends a poor prognosis. Pharmacological disruption of NH pathways early in HF may prevent CRS and, therefore, improve outcomes.

Renal dysfunction is the most important predictor of the extent and severity of coronary artery disease in patients with diabetes mellitus

OBJECTIVES

Diabetic patients tend to have more extensive and diffuse coronary artery disease (CAD) that may contribute to the less favorable outcomes in them. The aim of this study was to elucidate the predictors of the angiographic severity and extent of CAD in patients with diabetes.

METHODS

A total of 203 diabetic patients (116 men; mean age, 61.9+/-10.8) who were referred for a first coronary angiogram were included. The extent and severity of CAD was assessed in several ways. The first was a simple classification in one-vessel, two-vessel, and three-vessel disease scoring system. The total numbers of segments with > or = 20 and > or = 50% stenosis were calculated as CASS 20 and CASS 50 scores, respectively. Hamsten and Gensini scores were also calculated.

RESULTS

Of the 203 patients included in the study, 175 (86.2%) had CAD. Multivariate ordinal logistic regression analysis showed that age (Wald 5.741, P=0.017), glomerular filtration rate (Wald 5.032, P=0.025), previous myocardial infarction (Wald 10.955, P=0.001), and family history of CAD (Wald 7.236, P=0.007) were independent predictors of the severity of CAD, as assessed by the clinical zero-vessel to three-vessel disease scoring system. On stepwise multiple linear regression analysis, glomerular filtration rate was an independent predictor of the CASS 20 (r=-0.221, P=0.004), CASS 50 (r=-0.239, P=0.005), Gensini (r=-0.328, P<0.001), and Hamsten (r=-0.320, P<0.001) scores. Previous myocardial infarction was an independent predictor of the CASS 50 (r=0.355, P<0.001), Gensini (r=0.350, P<0.001), and Hamsten (0.256, P<0.001) scores. Age and sex were independent predictors for the CASS 50 (r=0.174, P=0.039; r=0.172, P=0.016, respectively) and Hamsten (r=0.212, P=0.011; r=0.244, P=0.001, respectively) scores.

CONCLUSION

Renal function is one of the most important factors associated with the extent and severity of coronary atherosclerosis, whereas classical coronary risk factors and the degree of metabolic control were not associated with the severity of coronary atherosclerosis in diabetic patients.

Chronic kidney disease is associated with angiographic coronary artery disease

BACKGROUND/AIMS

Patients with chronic kidney disease (CKD) have a dramatically increased risk for cardiovascular mortality. Few prior studies have examined the independent association of CKD with coronary anatomy.

METHODS

We evaluated the relationship between CKD and severe coronary artery disease (CAD) in 261 male veterans with nuclear perfusion imaging tests suggesting coronary ischemia. We used chart review and patient and provider interviews to collect demographics, clinical characteristics, and coronary anatomy results. We defined CKD as an estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m2, based on the creatinine obtained prior to angiography. We defined significant coronary obstruction as at least one 70% or greater stenosis. We used logistic regression to determine whether CKD was independently associated with significant coronary obstruction.

RESULTS

The likelihood of CAD increased monotonically with decreasing eGFR, from 51% among patients with eGFR or = 90 ml/min/1.73 m2 to 84% in those with eGFR < 30 ml/min/1.73 m2 (p = 0.0046). Patients with CKD were more likely than those without CKD to have at least one significant coronary obstruction (75.9 vs. 60.7%, p = 0.016). Patients with CKD also had more significant CAD, that is, were more likely to have three-vessel and/or left main disease than those without CKD (34.9 vs. 16.9%, p = 0.0035). In logistic regression analysis, controlling for demographics and comorbidity, CKD continued to be independently associated with the presence of significant CAD (p = 0.0071).

CONCLUSION

CKD patients have a high prevalence of obstructive coronary disease, which may contribute to their high cardiovascular mortality.

The diagnostic accuracy of different natriuretic peptides in the investigation of canine cardiac disease

OBJECTIVES

We aimed to validate and determine the accuracy of a new sandwich ELISA for canine N-terminal pro-B-type natriuretic peptide (NT-proBNP) in the discrimination of canine patients with cardiac disease from those with respiratory disease and to determine the effect of confounding variables on NT-proBNP concentrations.

METHODS

Validation studies for the new assay were undertaken. Concentrations of N-terminal atrial natriuretic peptide (NT-proANP) and NT-proBNP in both ethylenediaminetetraacetic acid (EDTA) plasma and serum were estimated in samples from 77 dogs at a laboratory blinded to the clinical status of the patient. The diagnostic accuracy of the each sample type and test was evaluated using receiver operating characteristic curves. The effect of age, gender and indicators of renal function was evaluated using a multivariate regression analysis.

RESULTS

Concentrations of NT-proBNP in both serum and plasma accurately discriminated dogs with respiratory disease from those with cardiac disease, with an optimum cut-off concentration of 210 pmol/l. NT-proBNP concentrations were unaffected by sample type. Increasing creatinine concentration is associated with increasing concentration of NT-proBNP. Age and gender were not found to have significant effects on natriuretic peptide concentrations in this population.

CLINICAL SIGNIFICANCE

Canine NT-proBNP appears to be a useful marker of the presence of cardiac disease, although concentrations must be interpreted in the light of the patient's renal function.

Long-term outcomes after coronary artery bypass grafting: Preoperative kidney function is prognostic

OBJECTIVE

End-stage renal disease is an independent predictor of mortality after coronary artery bypass grafting. Limited information exists, however, regarding the impact of chronic kidney disease on long-term outcome after bypass grafting. The purpose of this study was to assess the impact of kidney function on long-term outcomes in patients undergoing coronary artery bypass grafting.

METHODS

We studied 931 consecutive patients undergoing coronary artery bypass grafting in a single center. Demographic and clinical data were collected preoperatively. Chronic kidney disease was defined preoperatively according to the Modification of Diet in Renal Disease equation as an estimated glomerular filtration rate less than 60 mL x min(-1) x 1.73 m(-2). Multivariate Cox proportional hazard analyses were performed to determine the independent prognostic factors after bypass grafting. The primary outcome was a composite, combining death, acute coronary syndrome, stroke or transient ischemic attack, and coronary or peripheral revascularization during follow-up. Secondary outcomes were overall causes of death and cardiovascular death, acute coronary syndrome, and stroke or transient ischemic attack.

RESULTS

One hundred fourteen (12.2%) patients had preoperative chronic kidney disease (estimated glomerular filtration rate range, 20.5-59.8 mL x min(-1) x 1.73 m(-2)). After a mean follow-up of 3.1 +/- 1.4 years (median, 3.3 years), chronic kidney disease was found to be an independent predictor of the composite outcome (hazard ratio and 95% confidence interval, 1.46 [1.01-2.11]; P = .0467) and overall death (hazard ratio and 95% confidence interval, 1.89 [1.16-3.07]; P = .0106).

CONCLUSIONS

Beyond the perioperative period, preoperative moderate-to-severe chronic kidney disease is an independent long-term predictor of cardiovascular events and total mortality after coronary artery bypass grafting. Chronic kidney disease status should be incorporated into prediction models and clinical risk assessments.

Long-Term Safety and Efficacy of Drug-Eluting Stents

BACKGROUND

The long-term safety and efficacy of drug-eluting stents (DES) have been questioned recently.

METHODS AND RESULTS

Between July 2002 and June 2005, 10,629 patients undergoing elective percutaneous coronary intervention with either DES (n=3064) or bare-metal stents (BMS, n=7565) were enrolled in a prospective registry comprising 13 hospitals. We assessed the cumulative incidence of major adverse cardiac events (death, acute myocardial infarction, and target-vessel revascularization) and angiographic stent thrombosis during 2-year follow-up. A propensity score analysis to adjust for different baseline clinical, angiographic, and procedural characteristics was performed. The 2-year unadjusted cumulative incidence of major adverse cardiac events was 17.8% in the DES group and 21.0% in the BMS group (P=0.003 by log-rank test). Angiographic stent thrombosis was 1.0% in the DES group and 0.6% in the BMS group (P=0.09). After adjustment, the 2-year cumulative incidence of death was 6.8% in the DES group and 7.4% in the BMS group (P=0.35), whereas the rates were 5.3% in DES and 5.8% in BMS for acute myocardial infarction (P=0.46), 9.1% in DES and 12.9% in BMS for target-vessel revascularization (P<0.00001), and 16.9% in DES and 21.8% in BMS for major adverse cardiac events (P<0.0001). Independent predictors of target-vessel revascularization in the DES group were diabetes mellitus (hazard ratio 1.36, 95% confidence interval 1.06 to 1.76), renal failure (hazard ratio 1.69, 95% confidence interval 1.06 to 2.69), and reference vessel diameter (hazard ratio 0.64, 95% confidence interval 0.45 to 0.93).

CONCLUSIONS

In this large real-world population, the beneficial effect of DES in reducing the need for new revascularization compared with BMS extends to 2 years without evidence of a worse safety profile.

Decreased effective blood volume in edematous disorders: what does this mean?

Edematous patients with renal sodium and water retention, particularly cardiac failure and cirrhosis, have been suggested to have a decreased "effective blood volume." This enigmatic and undefined term was coined because edematous patients were found to have increased, rather than the earlier proposed decreased, blood volumes. This article discusses the advances that have occurred in understanding the pathophysiology of edema as occurs in conditions such as cardiac failure, cirrhosis, and pregnancy. The regulatory mechanisms that lead to increased sodium and water retention by the normal kidney are related to arterial underfilling, as a result of a decrease in cardiac output, arterial vasodilation, or both.

Myocellular and interstitial edema and circulating volume expansion as a cause of morbidity and mortality in heart failure

BACKGROUND

Total body sodium and volume overload are the hallmarks of the congested state in the heart failure patient and result in a variety of deleterious pathophysiologic outcomes including ventricular chamber dilation, passive congestion of both encapsulated and nonencapsulated vital organs and myocardial edema and ischemia.

METHODS AND RESULTS

We propose that congestion is itself a disease state irrespective of the underlying cardiac or renal dysfunction and that sodium and volume overload are directly related to poor clinical outcomes in such patients. In this model, the target of decongestion therapy should be normalization of total body sodium and volume in an expeditious manner and with a durable result.

CONCLUSIONS

Additionally, novel tools to continuously measure the effectiveness and adequacy of decongestion therapy in all compartments are required if improved clinical outcomes are to be attained.

Amino Terminal B-Type Natriuretic Peptide, Renal Function, and Prognosis in Acute Heart Failure: A Hospital Cohort Study

BACKGROUND

Amino-terminal pro-brain natriuretic peptide (NT-proBNP) is a valuable diagnostic and prognostic test in heart failure (HF). Limited information is available concerning its use in patients with renal failure, in whom dependence on renal clearance may negatively affect its performance.

METHODS AND RESULTS

We evaluated influence of renal function on NT-proBNP levels and on its prognostic value after hospital discharge in 283 acute HF patients. Admission and discharge NT-proBNP levels were higher in patients with decreased estimated glomerular filtration rate (eGFR). In these patients discharge NT-proBNP above median was associated to occurrence of death or readmission at 6 months (hazard ratio [HR] 2.53, 95% confidence interval [CI] 1.27-5.03); in patients with normal eGFR, a trend to this association was found (HR 1.64, CI 0.98-2.76). Decrease in NT-proBNP less than 30% of baseline was associated to outcome in patients with normal eGFR (HR 2.68, CI 1.54-4.68) and decreased eGFR (HR 2.54, CI 1.49-4.33).

CONCLUSIONS

Acute HF patients with renal failure have higher NT-proBNP levels than those with normal renal function. Discharge NT-proBNP has long-term prognostic value in HF patients with renal dysfunction. NT-proBNP variations during hospitalization provide additional prognostic information either in patients with normal or reduced eGFR.

Left atrial appendage exclusion for stroke prevention in patients with nonrheumatic atrial fibrillation

The efficacy of oral anticoagulation (OAC) for stroke prevention in patients with nonrheumatic atrial fibrillation (AF) has clearly been established. However, a substantial number of patients with AF who are at high risk for thromboembolic events are not candidates for long-term OAC. The left atrial appendix (LAA) is the most common place of thrombosis in patients with AF, and it can easily be excluded from the systemic circulation at the time of cardiac surgery by excision, ligation, suturing, or stapling. Currently, removal of the LAA at the time of mitral valve surgery is recommended to reduce future stroke risk. The ongoing LAA Occlusion Study (LAAOS) is evaluating the efficacy of the routine LAA occlusion in patients undergoing elective coronary artery bypass graft surgery. Recently, two devices specifically designed for percutaneous transcatheter LAA occlusion have been introduced: the Percutaneous LAA Transcatheter Occlusion (PLAATO; Appriva Medical Inc) and WATCHMAN LAA system (Atritech, Inc). More than 200 PLAATO devices were implanted worldwide in patients with nonrheumatic AF who were at high risk for ischemic stroke and not candidates for long-term OAC. In a follow-up time of 258 patient-years, an estimated 61% reduction in stroke risk was achieved with PLAATO procedure. The WATCHMAN Left Atrial Appendage System for Embolic PROTECTion in Patients With Atrial Fibrillation (PROTECT AF) study was designed to demonstrate the safety and efficacy of the WATCHMAN device in patients with nonvalvular AF who are eligible for long-term OAC. The trial is assessing whether the treatment arm (WATCHMAN device) is noninferior to the control arm (warfarin). Although present results suggest that LAA occlusion may reduce the long-term stroke risk, available data are still very limited. At present, percutaneous LAA occlusion may be an acceptable option in selected high-risk patients with AF who are not candidates for OAC. The current understanding of LAA exclusion for the prevention of stroke in patients with nonrheumatic AF is the major focus of this review.

Ultrafiltration versus intravenous diuretics for patients hospitalized for acute decompensated heart failure

OBJECTIVES

This study was designed to compare the safety and efficacy of veno-venous ultrafiltration and standard intravenous diuretic therapy for hypervolemic heart failure (HF) patients.

BACKGROUND

Early ultrafiltration may be an alternative to intravenous diuretics in patients with decompensated HF and volume overload.

METHODS

Patients hospitalized for HF with > or =2 signs of hypervolemia were randomized to ultrafiltration or intravenous diuretics. Primary end points were weight loss and dyspnea assessment at 48 h after randomization. Secondary end points included net fluid loss at 48 h, functional capacity, HF rehospitalizations, and unscheduled visits in 90 days. Safety end points included changes in renal function, electrolytes, and blood pressure.

RESULTS

Two hundred patients (63 +/- 15 years, 69% men, 71% ejection fraction < or =40%) were randomized to ultrafiltration or intravenous diuretics. At 48 h, weight (5.0 +/- 3.1 kg vs. 3.1 +/- 3.5 kg; p = 0.001) and net fluid loss (4.6 vs. 3.3 l; p = 0.001) were greater in the ultrafiltration group. Dyspnea scores were similar. At 90 days, the ultrafiltration group had fewer patients rehospitalized for HF (16 of 89 [18%] vs. 28 of 87 [32%]; p = 0.037), HF rehospitalizations (0.22 +/- 0.54 vs. 0.46 +/- 0.76; p = 0.022), rehospitalization days (1.4 +/- 4.2 vs. 3.8 +/- 8.5; p = 0.022) per patient, and unscheduled visits (14 of 65 [21%] vs. 29 of 66 [44%]; p = 0.009). No serum creatinine differences occurred between groups. Nine deaths occurred in the ultrafiltration group and 11 in the diuretics group.

CONCLUSIONS

In decompensated HF, ultrafiltration safely produces greater weight and fluid loss than intravenous diuretics, reduces 90-day resource utilization for HF, and is an effective alternative therapy. (The UNLOAD trial; http://clinicaltrials.gov/ct/show/NCT00124137?order=1; NCT00124137).

Pathophysiology of volume overload in acute heart failure syndromes

The inability to effectively regulate volume status is a major consequence of acute heart failure syndromes (AHFS). A variety of pathophysiologic processes contribute to this impairment, most notably neurohormonal activation of the renin-angiotensin-aldosterone system, arginine vasopressin, and the sympathetic nervous system. As a result, addressing volume overload is one of the most challenging aspects of AHFS management. Neurohormonal activation leads to substantial changes in hemodynamics and myocardial remodeling, which further contribute to the severity of heart failure (HF) disease and thereby cyclically increase the risk of further neurohormonal activation. Pulmonary capillary wedge pressure is a dependable reflection of volume status and has been used as a surrogate marker in recent studies to assess disease progression in response to innovative HF treatment strategies. Future approaches to HF treatment should focus on the more accurate assessment and management of volume status in an effort to improve patient care.

Cardiovascular Outcomes and All-Cause Mortality: Exploring the Interaction Between CKD and Cardiovascular Disease

BACKGROUND

Chronic kidney disease (CKD) is a risk factor for cardiovascular disease (CVD). Concurrently, CVD may promote CKD, resulting in a vicious cycle. We evaluated this hypothesis by exploring whether CKD and CVD have an additive or synergistic effect on future cardiovascular and mortality outcomes.

METHODS

Patients were pooled from 4 community-based studies: Atherosclerosis Risk in Communities, Framingham Heart, Framingham Offspring, and Cardiovascular Health Study. CKD is defined by an estimated glomerular filtration rate less than 60 mL/min/1.73 m(2) (<1 mL/s/1.73 m(2)). Baseline CVD included myocardial infarction, angina, stroke, transient ischemic attack, claudication, heart failure, and coronary revascularization. The primary outcome is a composite of cardiac events, stroke, and death. Secondary outcomes included individual components. Multivariable analyses using Cox regression examined differences in study outcomes. The interaction of CKD and CVD was tested.

RESULTS

The study population included 26,147 individuals. During 10 years, 4% (n = 2,927) of individuals with no CKD or CVD developed the primary outcome, 33% (n = 518) with only CKD, 37% (n = 1,260) with only CVD, and 66% (n = 459) with both. Both CKD (hazard ratio [HR], 1.26; 95% confidence interval [CI], 1.16 to 1.35; P < 0.0001) and CVD (HR, 1.83; 95% CI, 1.72 to 1.95; P < 0.0001) were independent risk factors for the primary outcome. The interaction term CKD x CVD was not statistically significant (HR, 0.98; 95% CI, 0.85 to 1.13; P = 0.74). Similar results were obtained for secondary outcomes.

CONCLUSION

CKD and CVD are both strong independent risk factors for adverse cardiovascular and mortality outcomes in the general population. Although individuals with both risk factors are at extremely high risk, there does not appear to be a synergistic effect of CKD and CVD on outcomes.