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(Circulation. 2003;107:294.)
© 2003 American Heart Association, Inc.
Clinical Investigation and Reports |
From the Department of Medicine, Columbia Presbyterian Medical Center, New York, NY.
Correspondence to Dr Donna M. Mancini, MD, Division of Circulatory Physiology, 622 W 168th St PH 1273, New York, NY 10032. E-mail dmm31{at}columbia.edu
| Abstract |
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Methods and Results Twenty-six anemic patients aged 57±11 years were randomized to receive EPO (15 000 to 30 000 IU per week) or placebo for 3 months. Parameters measured at baseline and end therapy included blood parameters (hemoglobin, hematocrit, plasma volume), exercise parameters (peak oxygen consumption [
O2], exercise duration, 6-minute walk), muscle aerobic metabolism (half-time of
O2 and near infrared recovery), and forearm vasodilatory function. EPO was well tolerated by all patients. Twelve patients in the EPO group felt improvement versus 1 in the placebo group (P<0.05). There were significant increases in hemoglobin (11.0±0.5 to 14.3±1.0 g/dL, P<0.05), peak
O2 (11.0±1.8 to 12.7±2.8 mL · min-1 · kg-1, P<0.05) and exercise duration (590±107 to 657±119 s, P<0.004) in the EPO group but no significant changes in the control group. Resting and hyperemic forearm vascular resistance and indices of the rate of muscle oxidative capacity were unchanged in both groups.
Conclusion EPO significantly enhances exercise capacity in patients with CHF. One mechanism of improvement in
O2 is increased oxygen delivery from increased hemoglobin concentration.
Key Words: exercise heart failure growth substances
| Introduction |
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A major limiting symptom in patients with CHF is exertional fatigue resulting from reduced cardiac output and intrinsic skeletal muscle and vascular abnormalities. Normalization of Hb concentration in patients with CHF may result in improved exercise capacity by increasing oxygen delivery. Alternatively, Hb may reduce oxidative stress in these patients by scavenging oxygen free radicals. This may improve vasodilatory capacity and/or increase rate of oxygen delivery. The purpose of our study was to investigate the effect of erythropoietin therapy on exercise capacity in patients with CHF and to define its potential mechanism(s). Accordingly, a randomized, single-blind, controlled study of the effect of erythropoietin on exercise performance, hematologic parameters, including plasma volume, and vasodilatory function was conducted in patients with moderate to severe CHF.
| Methods |
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Study Protocol
A randomized, single-blind, prospective study was performed with a 2:1 randomization of patients to erythropoietin (Amgen Inc) or placebo (0.9% saline). Patients in the control group received 1 subcutaneous injection of normal saline (0.5 mL). Patients randomized to EPO received 5000 U subcutaneously 3 times a week. If after 4 weeks the increase in Hb was <1 g/dL, the EPO dose was increased to 10 000 IU 3 times a week. Patients randomized to EPO were prescribed ferrous gluconate 325 mg daily and folate 1 mg daily. Follow-up visits were every 2 weeks for the first month and then monthly. During each follow-up visit, a complete blood count was performed. The study duration was 3 months or until hematocrit was
45%.
Measurements
Assessments performed at baseline and end therapy included red blood cell and plasma volumes, peak
O2, 6-minute walk test, Minnesota Living With Heart Failure Quality of Life questionnaire, patients global assessment, assessments of muscle aerobic capacity using half-time recovery of
O2, and near infrared absorption and vasodilatory function using forearm plethysmography.
Exercise Parameters
Maximal bicycle testing was performed in the fasting state with metabolic measurements (Medical Graphics 2001). Patients breathed through a disposable pneumotach. Exercise was begun at 0 watts and increased by 25 watts every 3 minutes until reaching the maximally tolerated workload. At the end of exercise, the patient continued breathing into the mouthpiece for 4 minutes.
O2 at the anaerobic threshold was identified as the nadir of the ventilatory equivalent for
O2. An un-encouraged 6-minute walk test was also performed. Patients completed a Minnesota Living With Heart Failure Questionnaire,6 and at the completion of the study were asked whether they felt improvement.
Hematinics and Plasma Volume
Serum erythropoietin level was measured by radioimmunoassay (Quest Diagnostics). The normal range was 4.1 to 19.5 mU/mL. Plasma and red blood cell volume were determined by the 131I-radioiodinated (131I) serum albumin technique as previously described7 to distinguish between true or dilutional anemia. Twenty-five µCi 131I serum albumin (Megatope, Iso-Tex Diagnostics, Inc) was injected into a peripheral vein from a prefilled syringe. Five cc of venous blood was collected before injection and every 6 minutes until 36 minutes after isotope injection. Specimens were analyzed with an automated system (BVA-100 Blood Volume Analyzer, Daxor Corp) and compared with normal values on the basis of age, sex, height, and weight.
Assessment of Muscle Oxidative Metabolism
Rate of skeletal muscle oxidative capacity was determined by near-infrared spectroscopy (NIRS) and by gas exchange analysis as previously described.8,9 In brief, an NIRS probe (Runman, NIM Inc) was secured to the thigh 10 cm above the patella over the vastus lateralis, and a rapidly inflating pneumatic cuff was placed above the probe. With the patient seated, the cuff was inflated to supra-systolic pressure for 3 minutes and released. The time to midpoint of recovery of the signal was measured.
Rate of skeletal muscle oxidative capacity was also measured by determining the kinetics of
O2 recovery. At the end of exercise, the workload was removed, but patients continued to breathe into the metabolic cart for 4 minutes. The half-time of recovery of oxygen consumption (T1/2
O2) is the time required for a 50% fall in the peak
O2 level.
Forearm Hemodynamics
Forearm blood flow (FBF, mL/min per 100 mL of forearm volume) was determined by venous occlusion strain gauge plethysmography at rest and after 5 minutes of arterial occlusion as previously described.10 For each measurement, forearm venous blood flow was occluded just proximal to the elbow with rapid inflation of a blood pressure cuff to 40 mm Hg. A wrist cuff was inflated to supra-systolic pressures 1 minute before and during each measurement. Five plethysmographic measurements were averaged for determination of FBF at rest. Postischemic FBF was determined as the maximum forearm blood flow determined within 5 seconds after the release of an upper arm blood pressure cuff inflated to supra-systolic pressure for 5 minutes. During each FBF measurement, mean arterial pressure was determined in the contra-lateral arm with an automated device (Dinamap, model 1846, Critikon). Forearm vascular resistance was determined as the ratio of mean arterial pressure and forearm flow.
Statistical Analysis
Intra-group differences were compared by paired t testing and inter-group differences by unpaired t testing. A P<0.05 was considered statistically significant. Noncontinuous variables were compared by
2 analysis. All results are reported as mean±SD.
| Results |
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O2 did not differ between the groups (Table 1). Background heart failure therapy included treatment with diuretics, digoxin, angiotensin-converting enzyme inhibitors or AII blockers, and ß-blockade and was not different between the 2 groups. One patient was not on digoxin, 2 were not on angiotensin-converting enzyme inhibitors or AII blockers, and 3 were not on ß-blockers.
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Tolerability
In the EPO group, duration of therapy averaged 70±11 days. Four patients were up-titrated to 10 000 U three times per week. Weight did not change in either group. Diuretic dose was increased in 5 patients in the erythropoietin group versus 3 patients in the control group (P=NS). EPO was well tolerated. None of the patients had thrombotic complications or hypertension. Four patients in the control group were hospitalized for decompensated CHF versus 1 patient in the EPO group, who ultimately died. The other 2 admissions in the EPO group were for syncope and pneumonia.
Hematologic Responses to EPO
Hemoglobin increased from 11±0.6 to 14.3±1.2 g/dL (P<0.0001, Figure 1). In the control group, hemoglobin was unchanged (10.9±1.1 versus 11.5±1.3 g/dL, P=NS).
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Red blood cell volume estimations were performed in 15 patients with the 131I-tagged albumin technique. Six (40%) of the 15 patients had normal red blood cell (RBC) volume as predicted from age, sex, and body surface area. The anemia in these patients was dilutional secondary to increased plasma volume.
Nine of the EPO-treated patients underwent 131I studies. At baseline, 5 patients had reduced RBC volume, whereas 4 had normal RBC volume. The response to EPO treatment for these 2 sub-groups is shown in Table 2. The increase in Hb was comparable in both groups, as was the increase in peak
O2. Mean RBC and plasma volume excess or deficit derived from the difference of the measured and ideal values are shown in Table 2. In the dilutional anemia sub-group, RBC volume seems to replace the plasma volume excess after EPO treatment.
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Effect of EPO on Exercise Parameters
Heart rate and blood pressure at rest and peak exercise did not change between baseline and end assessment in either group (Table 3). The respiratory quotient at baseline and end assessment did not change in either group, indicating comparable intensity of effort between the groups and the serial studies.
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Peak
O2 increased significantly from 11±0.8 to 12.7±2.8 mL · kg-1 · min-1 (P<0.05, Figure 2). In the control group, peak
O2 declined by an average of 0.5 mL · kg-1 · min-1 from 10.0±1.9 at baseline to 9.5±1.6 mL · kg-1 · min-1 (P=NS). Similarly,
O2 at the anaerobic threshold was significantly increased in the EPO-treated patients but was unchanged in the control group. A significant positive linear correlation was observed between the change in plasma Hb and the change in peak
O2 (Figure 3). Exercise duration tended to decrease in the control group but increased significantly in the EPO-treated patients. Submaximal exercise performance assessed using the 6-minute walk test increased significantly in the EPO-treated group but not in the control group (Table 3).
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Quality of Life
Twelve of the 15 patients on active EPO therapy felt improved versus 1 of 8 patients in the control group (P<0.05). In the control group, the Minnesota Living With Heart Failure Questionnaire score rose by an average of 10 points, indicating decreased quality of life (56 to 66). In the EPO-treated group, the score declined by an average of 9 points, representing subjective improvement (46 to 37) (P<0.04).
Effect of EPO on Muscle Oxidative Metabolism
No change in NIR recovery time was seen in the control (pre: 28±27; post: 34±34 s; P=NS) or EPO-treated patients (pre: 19±4; post: 16±4 s; P=NS) at baseline and end studies. The T1/2
O2, another index of skeletal muscle aerobic capacity, was unchanged in the control (pre: 115±35; post: 113±30 s; P=NS) and EPO-treated (pre: 152±35; post: 148±29 s; P=NS) groups.
Effect of EPO on Forearm Vasodilation
FBF and vascular resistance at rest and after 5 minutes of arterial occlusion are shown in Table 4. Rest and postischemic FBF and forearm vascular resistance did not change before and after treatment in either group.
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| Discussion |
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O2 with EPO therapy seems to be derived from increased oxygen delivery from the increased Hb concentration.
Anemia in CHF
Anemia is common in elderly patients with CHF and increases with disease severity.2,11,12 Anemia in CHF is frequently untreated, however, despite previous reports that anemia can contribute to the worsening of CHF.13 Recent analysis of the Studies Of Left Ventricular Dysfunction (SOLVD) database show that anemia is an independent risk factor for mortality in patients with left ventricular dysfunction.14 Potential mechanisms by which anemia could worsen CHF include exacerbation of myocardial and peripheral hypoxia, increased venous return and cardiac work, and consequent left ventricular hypertrophy.15 Hypoxia could also potentially lead to activation of neurohormones and cytokines. In turn, cytokines can exacerbate the anemia,3 leading to a vicious cycle, the recently coined cardio-renal-anemia syndrome.16 Normalization of Hb concentration in patients with CHF may interrupt this cycle.
The mean serum EPO level in our study was 24 mU/mL, which is slightly above the normal range of our laboratory. Previous studies reported elevated serum EPO levels in patients with severe CHF.17,18 The increased production of EPO in CHF patients with anemia may reflect the presence of renal hypoxia and a compensatory attempt to augment O2 delivery to peripheral tissues through erythrocytosis.
The pathogenesis of anemia in CHF is multifactorial. A pseudo or dilutional anemia from plasma volume overload4 may occur. In this study, 40% of patients who underwent 131I studies had normal red cell volume predicted on the basis of age, sex, and body surface area, suggesting a dilutional anemia due to plasma volume expansion. Despite the dilutional etiology of the anemia, EPO was well tolerated by the patients, with no excessive volume overload and with a significant improvement in exercise capacity. Treatment of these patients resulted in a beneficial shift in blood composition, with a reduction in plasma volume and increase in red blood cell volume that may explain the marked symptomatic improvement.
Use of EPO in Heart Failure
Silverberg et al2,5 had previously shown in nonrandomized trials that treatment of anemia with EPO and IV iron in patients with severe CHF improved the patients functional class and cardiac function. Our study confirms the tolerability of this drug in patients with heart failure. Similar to Silverberg et al, we observed a dramatic improvement in quality of life and almost uniform improvement in the patients global assessment with active treatment. We did not observe any improvement in renal function, similar to the second report by Silverberg et al.5 Although an increase in blood pressure has been reported with large doses of EPO,19,20 no effect on resting or exercise blood pressure was observed in our study cohort. Moreover, forearm vascular resistance was unchanged in those patients receiving active therapy.
Effect of EPO on Exercise Capacity
The effect of erythropoietin on exercise performance has previously been examined in small studies of athletes or normal subjects,21,22 where it was applied as a performance-enhancing drug. In these studies, an increase in exercise performance was observed. In patients with chronic renal insufficiency, EPO has also been shown to improve exercise capacity.23 Our findings extend these observations to patients with heart failure, in whom both submaximal and maximal exercise capacity was improved.
The mechanism by which EPO improves exercise capacity is not known. In sports medicine, the mechanism has been presumed to be from increased Hb concentration leading to increased oxygen delivery. In disease states where oxidative stress is increased, however, Hb may reduce oxidative stress by scavenging for O2 free radicals. This may improve endothelial function and/or increase rate of oxygen delivery. In end stage renal patients, EPO has been shown to improve skeletal muscle function and O2 use,24 as well as endothelial function.25 In our study, however, we found no evidence of these effects. Whether the use of oral iron supplementation masked any potential vasodilatory effects is unclear.
Two indirect assessments of muscle aerobic metabolism were obtained in this study. Previous investigators have demonstrated that the half-time of
O2 recovery correlates with metabolic recovery of the muscle9 and is slowed in patients with heart failure. Similarly, the half-time to recover muscle oxygenation using NIRS also correlates with muscle metabolic recovery. The prolonged kinetics of oxygen recovery may be due to redistribution of blood flow after exercise to adjacent areas of nonexercising muscle because of adrenergic mediated vasoconstriction, impaired maximal metabolic vasodilatation, or decrease in blood velocity. The
O2 half-time values in our study are comparable to those reported in patients with moderate to severe heart failure. No alteration was seen with EPO therapy. Similarly, the half-time to recover muscle oxygenation using NIRS was also unaffected by therapy. Whether this is the consequence of unaltered vasodilatory capacity or decreased blood velocity with higher Hb concentrations is unclear. Thus, in our protocol, the increment in
O2 with EPO therapy is not due to changes in muscle oxidative capacity.
The rate of rise of the Hb was more rapid in this study than that observed in prior reports.2,5 Rapid and near normal correction of the Hct to a mean of 42% in hemodialysis patients increased cardiovascular events compared with those maintained at a Hct of 30%.26 Although there is some uncertainty about the interpretation of these findings,27 there is increasing evidence that correction of anemia to a Hct of 36% is safe. In our study, this rapid replacement regimen was well tolerated, with no thrombotic or hypertensive events. Whether a slower and/or a more sustained increase in plasma Hb may have yielded greater improvement in maximal and submaximal exercise capacity as longer duration of treatment provided more time to reverse intrinsic skeletal muscle and vascular changes is unknown.
Proportional changes in Hb and
O2 would be expected on the basis of the Fick equation if we assume peak exercise cardiac output and the arterial-venous oxygen difference to be constant during the course of the study. In our study, the improvement in
O2, although significant, was less than anticipated because the average Hb in this study increased by 30%, whereas average
O2 increased by 15%. Further work is needed to determine the mechanisms underlying this discrepancy.
Study Limitations
This is a single center study that is limited by the small sample size and single blind design. The placebo group received active treatment, as at the start of the study each control subject received an injection of normal saline. The investigators were not blinded to the study, but many of the parameters that improved with treatment were objective and could not be easily biased by the investigator. Nevertheless, subtle biases can occur with the single blind design.
Clinical Implications
Our findings, together with those of Silverberg et al,2,5 suggest that treatment with EPO could be beneficial in anemic patients with CHF. These beneficial effects on exercise capacity and quality of life are seen whether the anemia is true or dilutional in nature. Our findings need to be confirmed by multicenter clinical trials.
| Conclusions |
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O2 with EPO therapy is the increased oxygen delivery from increased Hb concentration. | Acknowledgments |
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Received August 1, 2002; revision received October 3, 2002; accepted October 7, 2002.
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C. Cote, M. D. Zilberberg, S. H. Mody, L. J. Dordelly, and B. Celli Haemoglobin level and its clinical impact in a cohort of patients with COPD Eur. Respir. J., May 1, 2007; 29(5): 923 - 929. [Abstract] [Full Text] [PDF] |
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S. Eddicks, K. Maier-Hauff, M. Schenk, A. Muller, G. Baumann, and H. Theres Thoracic spinal cord stimulation improves functional status and relieves symptoms in patients with refractory angina pectoris: the first placebo-controlled randomised study Heart, May 1, 2007; 93(5): 585 - 590. [Abstract] [Full Text] [PDF] |
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M. A. Fischer, C. A. Morris, W. C. Winkelmayer, and J. Avorn Nononcologic Use of Human Recombinant Erythropoietin Therapy in Hospitalized Patients Arch Intern Med, April 23, 2007; 167(8): 840 - 846. [Abstract] [Full Text] [PDF] |
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Y. Asaumi, Y. Kagaya, M. Takeda, N. Yamaguchi, H. Tada, K. Ito, J. Ohta, T. Shiroto, K. Shirato, N. Minegishi, et al. Protective Role of Endogenous Erythropoietin System in Nonhematopoietic Cells Against Pressure Overload-Induced Left Ventricular Dysfunction in Mice Circulation, April 17, 2007; 115(15): 2022 - 2032. [Abstract] [Full Text] [PDF] |
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J. M. Shammo and F. M. Stewart Hematopoietic growth factors ASH Self-Assessment Program, January 1, 2007; 2007(1): 45 - 60. [Full Text] [PDF] |
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C. Lundby, J. J. Thomsen, R. Boushel, M. Koskolou, J. Warberg, J. A. L. Calbet, and P. Robach Erythropoietin treatment elevates haemoglobin concentration by increasing red cell volume and depressing plasma volume J. Physiol., January 1, 2007; 578(1): 309 - 314. [Abstract] [Full Text] [PDF] |
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E. Lipsic, R. G. Schoemaker, P. van der Meer, A. A. Voors, D. J. van Veldhuisen, and W. H. van Gilst Protective Effects of Erythropoietin in Cardiac Ischemia: From Bench to Bedside J. Am. Coll. Cardiol., December 5, 2006; 48(11): 2161 - 2167. [Abstract] [Full Text] [PDF] |
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R. V. Milani, C. J. Lavie, M. R. Mehra, and H. O. Ventura Understanding the Basics of Cardiopulmonary Exercise Testing Mayo Clin. Proc., December 1, 2006; 81(12): 1603 - 1611. [Abstract] [Full Text] [PDF] |
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N. Valeur, O. W. Nielsen, J. J.V. McMurray, C. Torp-Pedersen, L. Kober, and TRACE Study Group Anaemia is an independent predictor of mortality in patients with left ventricular systolic dysfunction following acute myocardial infarction Eur J Heart Fail, October 1, 2006; 8(6): 577 - 584. [Abstract] [Full Text] [PDF] |
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A. P. Bolger, F. R. Bartlett, H. S. Penston, J. O'Leary, N. Pollock, R. Kaprielian, and C. M. Chapman Intravenous Iron Alone for the Treatment of Anemia in Patients With Chronic Heart Failure J. Am. Coll. Cardiol., September 19, 2006; 48(6): 1225 - 1227. [Abstract] [Full Text] [PDF] |
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Q. Feng Beyond erythropoiesis: The anti-inflammatory effects of erythropoietin Cardiovasc Res, September 1, 2006; 71(4): 615 - 617. [Full Text] [PDF] |
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Y. Li, G. Takemura, H. Okada, S. Miyata, R. Maruyama, L. Li, M. Higuchi, S. Minatoguchi, T. Fujiwara, and H. Fujiwara Reduction of inflammatory cytokine expression and oxidative damage by erythropoietin in chronic heart failure Cardiovasc Res, September 1, 2006; 71(4): 684 - 694. [Abstract] [Full Text] [PDF] |
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A. S. Go, J. Yang, L. M. Ackerson, K. Lepper, S. Robbins, B. M. Massie, and M. G. Shlipak Hemoglobin Level, Chronic Kidney Disease, and the Risks of Death and Hospitalization in Adults With Chronic Heart Failure: The Anemia in Chronic Heart Failure: Outcomes and Resource Utilization (ANCHOR) Study Circulation, June 13, 2006; 113(23): 2713 - 2723. [Abstract] [Full Text] [PDF] |
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M. Komajda, S. D. Anker, A. Charlesworth, D. Okonko, M. Metra, A. Di Lenarda, W. Remme, C. Moullet, K. Swedberg, J. G.F. Cleland, et al. The impact of new onset anaemia on morbidity and mortality in chronic heart failure: results from COMET Eur. Heart J., June 2, 2006; 27(12): 1440 - 1446. [Abstract] [Full Text] [PDF] |
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Y.-D. Tang and S. D. Katz Anemia in Chronic Heart Failure: Prevalence, Etiology, Clinical Correlates, and Treatment Options Circulation, May 23, 2006; 113(20): 2454 - 2461. [Full Text] [PDF] |
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E. O'Meara, T. Clayton, M. B. McEntegart, J. J.V. McMurray, C. C. Lang, S. D. Roger, J. B. Young, S. D. Solomon, C. B. Granger, J. Ostergren, et al. Clinical Correlates and Consequences of Anemia in a Broad Spectrum of Patients With Heart Failure: Results of the Candesartan in Heart Failure: Assessment of Reduction in Mortality and Morbidity (CHARM) Program Circulation, February 21, 2006; 113(7): 986 - 994. [Abstract] [Full Text] [PDF] |
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T. Similowski, A. Agusti, W. MacNee, and B. Schonhofer The potential impact of anaemia of chronic disease in COPD Eur. Respir. J., February 1, 2006; 27(2): 390 - 396. [Abstract] [Full Text] [PDF] |
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G. M. Felker, W. G. Stough, L. K. Shaw, and C. M. O'Connor Anaemia and coronary artery disease severity in patients with heart failure Eur J Heart Fail, January 1, 2006; 8(1): 54 - 57. [Abstract] [Full Text] [PDF] |
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C. Opasich, M. Cazzola, L. Scelsi, S. De Feo, E. Bosimini, R. Lagioia, O. Febo, R. Ferrari, A. Fucili, R. Moratti, et al. Blunted erythropoietin production and defective iron supply for erythropoiesis as major causes of anaemia in patients with chronic heart failure Eur. Heart J., November 1, 2005; 26(21): 2232 - 2237. [Abstract] [Full Text] [PDF] |
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J. George, E. Goldstein, A. Abashidze, D. Wexler, S. Hamed, H. Shmilovich, V. Deutsch, H. Miller, G. Keren, and A. Roth Erythropoietin promotes endothelial progenitor cell proliferative and adhesive properties in a PI 3-kinase-dependent manner Cardiovasc Res, November 1, 2005; 68(2): 299 - 306. [Abstract] [Full Text] [PDF] |
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M. Kosiborod, J. P. Curtis, Y. Wang, G. L. Smith, F. A. Masoudi, J. M. Foody, E. P. Havranek, and H. M. Krumholz Anemia and Outcomes in Patients With Heart Failure: A Study From the National Heart Care Project Arch Intern Med, October 24, 2005; 165(19): 2237 - 2244. [Abstract] [Full Text] [PDF] |
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A. L. Clark and J. G.F. Cleland Anemia and Chronic Heart Failure: Are We Asking the Right Questions? Circulation, September 20, 2005; 112(12): 1681 - 1683. [Full Text] [PDF] |
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I. S. Anand, M. A. Kuskowski, T. S. Rector, V. G. Florea, R. D. Glazer, A. Hester, Y. T. Chiang, N. Aknay, A. P. Maggioni, C. Opasich, et al. Anemia and Change in Hemoglobin Over Time Related to Mortality and Morbidity in Patients With Chronic Heart Failure: Results From Val-HeFT Circulation, August 23, 2005; 112(8): 1121 - 1127. [Abstract] [Full Text] [PDF] |
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J. G.F. Cleland, A. P. Coletta, A. L. Clark, P. Velavan, and L. Ingle Clinical trials update from the European Society of Cardiology Heart Failure meeting and the American College of Cardiology: Darbepoetin alfa study, ECHOS, and ASCOT-BPLA Eur J Heart Fail, August 1, 2005; 7(5): 937 - 939. [Abstract] [Full Text] [PDF] |
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P. van der Meer, E. Lipsic, R. H. Henning, K. Boddeus, J. van der Velden, A. A. Voors, D. J. van Veldhuisen, W. H. van Gilst, and R. G. Schoemaker Erythropoietin Induces Neovascularization and Improves Cardiac Function in Rats With Heart Failure After Myocardial Infarction J. Am. Coll. Cardiol., July 5, 2005; 46(1): 125 - 133. [Abstract] [Full Text] [PDF] |
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T. Troosters, R. Casaburi, R. Gosselink, and M. Decramer Pulmonary Rehabilitation in Chronic Obstructive Pulmonary Disease Am. J. Respir. Crit. Care Med., July 1, 2005; 172(1): 19 - 38. [Full Text] [PDF] |
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J. George, S. Patal, D. Wexler, A. Abashidze, H. Shmilovich, T. Barak, D. Sheps, and G. Keren Circulating Erythropoietin Levels and Prognosis in Patients With Congestive Heart Failure: Comparison With Neurohormonal and Inflammatory Markers Arch Intern Med, June 13, 2005; 165(11): 1304 - 1309. [Abstract] [Full Text] [PDF] |
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S. Namiuchi, Y. Kagaya, J. Ohta, N. Shiba, M. Sugi, M. Oikawa, H. Kunii, H. Yamao, N. Komatsu, M. Yui, et al. High Serum Erythropoietin Level Is Associated With Smaller Infarct Size in Patients With Acute Myocardial Infarction Who Undergo Successful Primary Percutaneous Coronary Intervention J. Am. Coll. Cardiol., May 3, 2005; 45(9): 1406 - 1412. [Abstract] [Full Text] [PDF] |
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T. O. Cheng Is There an Optimal Hematocrit Value for Cardiac Patients? J. Am. Coll. Cardiol., May 3, 2005; 45(9): 1549 - 1549. [Full Text] |
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L. G. Olsson, K. Swedberg, A. L. Clark, K. K. Witte, and J. G.F. Cleland Six minute corridor walk test as an outcome measure for the assessment of treatment in randomized, blinded intervention trials of chronic heart failure: a systematic review Eur. Heart J., April 2, 2005; 26(8): 778 - 793. [Abstract] [Full Text] [PDF] |
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A. Ishani, E. Weinhandl, Z. Zhao, D. T. Gilbertson, A. J. Collins, S. Yusuf, and C. A. Herzog Angiotensin-converting enzyme inhibitor as a risk factor for the development of anemia, and the impact of incident anemia on mortality in patients with left ventricular dysfunction J. Am. Coll. Cardiol., February 1, 2005; 45(3): 391 - 399. [Abstract] [Full Text] [PDF] |
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K. Maiese, F. Li, and Z. Z. Chong New Avenues of Exploration for Erythropoietin JAMA, January 5, 2005; 293(1): 90 - 95. [Abstract] [Full Text] [PDF] |
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J. J.V. McMurray and M. A. Pfeffer The year in heart failure J. Am. Coll. Cardiol., December 21, 2004; 44(12): 2398 - 2405. [Full Text] [PDF] |
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K. Caiola and J. W. Cheng Use of Erythropoietin in Heart Failure Management Ann. Pharmacother., December 1, 2004; 38(12): 2145 - 2149. [Abstract] [Full Text] [PDF] |
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G.M. Felker, K. F. Adams Jr, W. A. Gattis, and C. M. O'Connor Anemia as a risk factor and therapeutic target in heart failure J. Am. Coll. Cardiol., September 1, 2004; 44(5): 959 - 966. [Abstract] [Full Text] [PDF] |
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R. V. Milani, C. J. Lavie, and M. R. Mehra Cardiopulmonary Exercise Testing: How Do We Differentiate the Cause of Dyspnea? Circulation, July 27, 2004; 110(4): e27 - e31. [Full Text] [PDF] |
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I. Anand, J. J.V. McMurray, J. Whitmore, M. Warren, A. Pham, M. A. McCamish, and P. B.J. Burton Anemia and Its Relationship to Clinical Outcome in Heart Failure Circulation, July 13, 2004; 110(2): 149 - 154. [Abstract] [Full Text] [PDF] |
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P. van der Meer, A. A. Voors, E. Lipsic, T. D. J. Smilde, W. H. van Gilst, and D. J. van Veldhuisen Prognostic value of plasma erythropoietin on mortality in patients with chronic heart failure J. Am. Coll. Cardiol., July 7, 2004; 44(1): 63 - 67. [Abstract] [Full Text] [PDF] |
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R. Sharma, D. P Francis, B. Pitt, P. A Poole-Wilson, A. J.S Coats, and S. D Anker Haemoglobin predicts survival in patients with chronic heart failure: a substudy of the ELITE II trial Eur. Heart J., June 2, 2004; 25(12): 1021 - 1028. [Abstract] [Full Text] [PDF] |
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S. Z. Pantilat and A. E. Steimle Palliative Care for Patients With Heart Failure JAMA, May 26, 2004; 291(20): 2476 - 2482. [Abstract] [Full Text] [PDF] |
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P. van der Meer, A. A. Voors, E. Lipsic, W. H. van Gilst, and D. J. van Veldhuisen Erythropoietin in cardiovascular diseases Eur. Heart J., February 2, 2004; 25(4): 285 - 291. [Abstract] [Full Text] [PDF] |
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S. D. Roger, L. P. McMahon, A. Clarkson, A. Disney, D. Harris, C. Hawley, H. Healy, P. Kerr, K. Lynn, A. Parnham, et al. Effects of Early and Late Intervention with Epoetin {alpha} on Left Ventricular Mass among Patients with Chronic Kidney Disease (Stage 3 or 4): Results of a Randomized Clinical Trial J. Am. Soc. Nephrol., January 1, 2004; 15(1): 148 - 156. [Abstract] [Full Text] [PDF] |
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H. K. Eltzschig, R. Ehlers, S. K. Shernan, W. Rodriguez, S. M. Silver, D. Schoevaerdts, C. Swine, D. Vanpee, M. Jessup, and S. Brozena Heart Failure N. Engl. J. Med., September 4, 2003; 349(10): 1002 - 1004. [Full Text] [PDF] |
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K. J Smith, A. J Bleyer, W. C Little, and D. C Sane The cardiovascular effects of erythropoietin Cardiovasc Res, September 1, 2003; 59(3): 538 - 548. [Abstract] [Full Text] [PDF] |
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K. Schroecksnadel, B. Wirleitner, D. Fuchs, W. Steinborn, P. Ponikowski, S. Anker, P. van der Meer, W. H. van Gilst, D. J. van Veldhuisen, J. Ezekowitz, et al. Anemia and Congestive Heart Failure * Response Circulation, August 12, 2003; 108 (6): e41 - e42. [Full Text] [PDF] |
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