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J Am Coll Cardiol, 2000; 35:701-705 © 2000 by the American College of Cardiology Foundation |





* Department of Cardiology and Department of Nuclear Medicine, Baragwanath Hospital, Johannesburg, South Africa
Department of Hematology and Molecular Medicine, University of the Witwatersrand, Johannesburg, South Africa
Manuscript received May 11, 1999; revised manuscript received October 5, 1999, accepted November 17, 1999.
Reprint requests and correspondence: Dr. Daniel Skudicky, Department of Cardiology, Baragwanath Hospital, P.O. Bertsham 2013, Johannesburg, South Africa
psareli{at}iafrica.com
| Abstract |
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1) To evaluate the outcome of patients with peripartum cardiomyopathy (PPC) on current treatment for heart failure, 2) to assess the circulating plasma levels of cytokines and Fas receptors and 3) to identify predictors of prognosis.
BACKGROUND
Previous studies in patients with PPC were done when angiotensin-converting enzyme (ACE) inhibitors and beta-adrenergic blocking agents were not routinely used in heart failure. Inflammatory cytokines play an important role in the pathogenesis and progression of heart failure of other etiologies. However, there is a paucity of data regarding cytokine expression in patients with PPC. Plasma concentrations of Fas receptors (an apoptosis-signalling receptor) have not been reported in this population.
METHODS
We followed prospectively 29 consecutive black women with PPC. All patients were treated with diuretics, digoxin, enalapril and carvedilol. Echocardiograms were performed at baseline and after six months of treatment. Cytokine and soluble Fas/APO-1 plasma levels were measured at baseline.
RESULTS
Tumor necrosis factor-alpha, interleukin-6 and Fas/APO-1 levels were significantly elevated in the study patients compared with 20 healthy volunteers. Eight patients died. sFas/APO-1 levels were significantly higher in patients who died compared with survivors (8.98 ± 4.5 vs. 5.33 ± 3 U/ml, respectively, p = 0.02). At six months, ejection fraction improved from 26.7 ± 10 to 42.7 ± 16%, p = 0.00003, with an increment of more than 10 U in 10 patients (28.1 ± 4 to 51.9 ± 8%, p = 0.000008).
CONCLUSIONS
Cytokine and sFas levels are elevated in patients with PPC. Despite treatment with ACE inhibitors and beta-blockers, mortality remains high. However, in 34% of the patients, left ventricular function almost completely normalized.
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There is accumulating evidence that inflammatory cytokines play an important role in the pathogenesis and progression of heart failure (78). Elevated levels of circulating cytokines have been described in advanced heart failure of other etiologies (9). However, there is a paucity of data regarding cytokine expression in patients with PPC.
Loss of myocytes due to apoptosis or programmed cell death occurs in patients with heart failure and may contribute to progressive myocardial dysfunction (1011). Fas is an apoptosis-signalling surface receptor known to trigger programmed cell death in a variety of cell types (1213). Increased plasma levels of soluble Fas receptors have been reported in patients with heart failure (14) although its significance is still not clearly established. There are no data regarding the plasma concentrations of Fas receptors in patients with peripartum cardiomyopathy.
The purpose of the study was: 1) to evaluate the outcome of patients with PPC on current treatment for heart failure, 2) to assess the circulating plasma levels of cytokines tumor necrosis factor (TNF)-alpha and interleukin-6 and Fas receptors in this population, and 3) to identify predictors of prognosis.
| Methods |
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16 years, 2) New York Heart Association (NYHA) functional class (FC) IIIV, 3) symptoms of congestive heart failure that developed in the last trimester of pregnancy or in the first six months postpartum, 4) no other identifiable cause of heart failure and no demonstrable cardiac disease in the last three months of pregnancy, 5) left ventricular ejection fraction
40% by transthoracic echocardiography, 6) sinus rhythm, and 7) eligible patients in whom high quality echocardiographic images could be obtained. Exclusion criteria were: 1) chronic obstructive pulmonary disease, 2) significant organic valvular heart disease, 3) systolic blood pressure >170 mm Hg or diastolic blood pressure >105 mm Hg, 4) clinical conditions other than cardiomyopathy that could increase the cytokine levels, (i.e., rheumatoid arthritis, sepsis, acquired immunodeficiency syndrome), 5) significant liver disease (defined as enzymes >2 times the upper limit of normal), and 6) severe anemia (hemoglobin concentration <9 gm/dl).
All patients received treatment with digoxin, diuretics and enalapril. Patients with an ejection fraction
25% or left ventricular thrombus received anticoagulation therapy. Carvedilol was added after resolution of overt heart failure, and the dose was slowly titrated up to a target of 25 mg twice daily if well tolerated. Patients attended the cardiac clinic at least once a month.
Cytokine and Fas/APO-1 plasma levels. Fifteen milliliters of blood were withdrawn from an antecubital vein and collected into prechilled evacuated tubes containing ethylenediaminetetraacetic acid. Plasma was separated by centrifugation at 2,500 rpm for 12 min within 15 min of collection. Aliquots were stored at 70°C. Cytokine measurements were performed using a commercially available enzyme-linked immunoassay (Amersham, Maidstone). The average of triplicate undiluted determinations was calculated. Fas/APO-1 was measured with a nonisotopic quantitative immunoassay (Calbiochem) appropriately diluted. In order to obtain reference values for the population studied, plasma was obtained from 20 age-matched black healthy volunteers. None of the patients or normal volunteers received anti-inflammatory drugs in the four weeks before the cytokine determination.
Echocardiographic studies.
Two-dimensional targeted M-mode echocardiography with Doppler color flow mapping was performed using a Hewlett Packard Sonos 5500 echocardiograph attached to a 2.5 or 3.5 Mhz transducer. All studies were recorded on videotape and were done by the same operator. Left ventricular dimensions were measured according to the American Society of Echocardiography guidelines (15). For left ventricular measurements, an average of
3 beats was obtained. The left ventricular ejection fraction was determined as previously described (16). None of the patients had paradoxical septal motion (no patient had left bundle branch block). Diastolic mitral flow was assessed by pulsed-wave Doppler echocardiography from the apical four-chamber view. The E-wave deceleration time was measured as the interval between the peak early diastolic velocity and the point at which the steepest deceleration slope was extrapolated to the zero line. A diastolic restrictive pattern was defined if the transmitral E/A ratio was
2 or if it was 1 to 2 with an E-wave deceleration time
140 ms (17). Patients were arbitrarily defined as improvers if they fulfilled all of the following criteria at the end of the study: 1) FC I or II, 2) a relative increment in ejection fraction
20% from baseline, and 3) left ventricular ejection fraction
30%.
Statistical analysis. Data are presented as mean ± standard deviation. Group comparisons were made by use of Mann-Whitney U test or binomial test as appropriate. Wilcoxon matched pairs test was used for comparison of baseline data and the results after six months. Logistic regression analysis was used to predict the probability of improvement (as defined in the echocardiography section). Data were analyzed on a personal computer by use of a commercially available statistical program (Statistica). Significance was assumed at a two-tailed value of p < 0.05.
| Results |
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Fas/APO-1. The soluble form of the Fas/APO-1 was significantly higher in the PPC patients compared with the healthy volunteers (5.99 ± 4 U/ml vs. 0.84 ± 0.21 U/ml, p = 0.0003). There was no significant correlation between sFas/APO-1 and cytokine levels.
Predictors of outcome. Twelve patients (48%) were defined as improvers according to our prespecified criteria. Patients who were defined as improvers had a higher baseline ejection fraction compared with the nonimprovers (29 ± 5% vs. 20 ± 10%, p = 0.004) and higher baseline systolic blood pressure (114 ± 14 mm Hg vs. 102 ± 15 mm Hg, p = 0.04). No other significant differences in baseline clinical or echocardiographic variables were observed between these two groups. Of all the baseline variables analyzed, only left ventricular ejection fraction emerged as an independent predictor of improvement in the logistic regression analysis (p = 0.04). Baseline levels of cytokines and Fas receptors were similar in improvers and nonimprovers, but plasma levels of Fas were higher in the eight patients who died compared with the survivors (8.98 ± 4 U/ml vs. 5.33 ± 3 U/ml, p = 0.02).
| Discussion |
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In our study, ejection fraction at presentation was the strongest predictor of outcome, and this was in accordance with previously published data (20). However, variables previously reported by others (4,5,21) as predictors of outcome such as age above 30 years, higher parity, later onset of symptoms after delivery and twin deliveries were not confirmed in this study.
Cytokines and soluble Fas/APO-1 receptors. In patients with heart failure, inflammatory cytokines are increased and correlate with the severity of symptoms (89) and prognosis (8,22). Belder et al. (23) found no detectable plasma TNF-alpha levels in three patients with PPC. However, the calcium-independent inducible nitric oxide iNOS synthase in heart tissue from these patients was elevated. Contrary to that, in this study we found a significant elevation in the plasma levels of cytokines. However, there was no correlation between the cytokine levels and left ventricular function or outcome.
Recent reports have suggested that interleukin-6 has a procoagulant effect via an increase in the expression of prothrombotic proteins such as PAI-1 (24). In 21% of our study group, a thrombus was detected in the left ventricular cavity on echocardiography. Interestingly, the Interleukin-6 levels in patients with left ventricular thrombus were significantly higher compared with the rest of the study population.
Fas and Fas ligand are cell surface proteins playing a key role in programmed cell death (25,26). Increased percentages of apoptotic cardiomyocytes (10,11) and elevated levels of plasma soluble Fas (14) were reported in patients with chronic heart failure of other etiologies, but there are no data regarding soluble Fas levels in patients with PPC. In this study, plasma Fas levels were significantly elevated compared with the normal volunteers. Furthermore, baseline soluble Fas concentrations were higher among the patients who died during the study period. Due to the small sample size, we cannot definitely established the role of Fas levels as a predictor of mortality in this population, but this deserves further investigation.
Conclusions. Similar to other etiologies of heart failure, we found elevated levels of cytokines and Fas/APO-1 in patients with PPC. Despite the addition of ACE inhibitors and beta-blockers to the therapy, the mortality remains very high. However, most of the patients that were alive six months after the initiation of therapy improved left ventricular function significantly.
| Footnotes |
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| References |
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