Atrial natriuretic peptide as a marker for doxorubicin-induced cardiotoxic effects

Troponins and Natriuretic Peptides in Cardio-Oncology Patients-Data From the ECoR Registry

BACKGROUND

The long-term survival of cancer patients has significantly improved over the past years. Despite their therapeutic efficacy, various cancer therapies are associated with cardiotoxicity. Therefore, timely detection of cardiotoxic adverse events is crucial. However, the clinical assessment of myocardial damage caused by cancer therapy remains difficult.

METHODS

This retrospective study was performed to evaluate the diagnostic value of cardiac troponin I (cTnI) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) for monitoring cancer therapy-induced cardiomyopathy. A total of 485 cancer patients referred to our cardio-oncology unit between July 2018 and January 2020 were selected from our Essen Cardio-oncology Registry (ECoR). We included patients with all types of cancer. Plasma concentrations of cTnI and NT-proBNP were measured by radioimmunoassay, and two-dimensional left ventricular ejection fraction (2D-LVEF), diastolic function, and global longitudinal strain (GLS) were measured by transthoracic echocardiography. In 116 patients, assessment was conducted before the induction of cancer therapy and during a short-term follow-up period; n = 42 of these were treated for malignant melanoma, and n = 42 with serial measurements were under treatment for breast cancer.

RESULTS

In cross-sectional data, elevated NT-proBNP was associated with reduced LVEF and pathological GLS in the total cohort. A total of 116 patients had serial LVEF and biomarker measurements, and changes in NT-proBNP and troponin correlated with changes in LVEF during follow-up investigations. Similar to the total cohort, a subgroup of patients treated for malignant melanoma showed a correlation between the change in cTnI and the change in LVEF. In a subgroup analysis of patients undergoing breast cancer therapy, a correlation between the change in NT-proBNP and the change in LVEF could be detected. Thirty patients presented with chemotherapy-induced cardiomyopathy, defined as a significant LVEF decrease (> 10%) to a value below 50%. The number of patients with increased cTnI and NT-proBNP was significantly higher in patients with chemotherapy-induced cardiomyopathy than in patients without cardiotoxicity. Patients with positive cTnI and NT-proBNP were more likely to have a history of coronary heart disease, atrial fibrillation, and arterial hypertension.

CONCLUSION

Our data suggest that cardiac biomarkers play an important role in the detection of cancer therapy-induced cardiotoxicity. Larger systematic assessment in prospective cohorts is mandatory.

Alternative Biomarkers for Combined Biology

Chemotherapy-related cardiac dysfunction (CRCD) has challenged clinicians to hesitate in using cardiotoxic agents such as anthracycline and several protein kinase inhibitors. As early detection of CRCD and timely cessation of cardiotoxic agents became a strategy to avoid CRCD, cardiac troponin and natriuretic peptide are measured to monitor cardiotoxicity; however, there are inconsistencies in their predictability of CRCD. Alternative biomarkers have been researched extensively for potential use as more sensitive and accurate biomarkers. The mechanisms of CRCD and previous studies on traditional and novel biomarkers for CRCD are examined to enlighten future direction of investigation in this combined biology.

Biomarkers for monitoring chemotherapy-induced cardiotoxicity

Cardiotoxicity, including acute and late-onset cardiotoxicity, is a well-known adverse effect of many types of antitumor agents. Early identification of patients with cardiotoxicity is important to ensure prompt treatment and minimize toxic effects. The etiology of chemotherapy-induced cardiotoxicity is multifactorial. Traditional methods for assessment of chemotherapy-induced cardiotoxicity typically involve serial measurements of cardiac function via multi-modality imaging techniques. Typically, however, significant left ventricular dysfunction has already occurred when cardiotoxicity is detected by imaging techniques. Biomarkers, most importantly cardiac natriuretic peptides and troponins, are promising markers for identifying patients potentially at risk for clinical heart failure symptoms. This review summarizes the recent progress in clinical utilization of biomarkers for early diagnosis of acute cardiotoxicity and for prediction of late-onset cardiotoxicity. We also discuss the conflicting results of different studies and the association of results with study design.

Emerging delivery systems to reduce doxorubicin cardiotoxicity and improve therapeutic index: focus on liposomes

Anthracyclines are powerful anticancer agents and among the most important tools in the chemotherapy armamentarium of medical oncologists. They are approved for use in the treatment of a broad variety of solid and hematologic neoplasms. However, the usefulness of these agents, particularly doxorubicin, the most widely used anthracycline, is limited by considerable toxicity, especially damage to the cardiac muscle, which is cumulative and mostly irreversible, restricting extended use of this drug. In the last 30 years, extensive research with a variety of drug-delivery systems has attempted to overcome this limitation, with clinical success mostly confined to liposome formulations. Liposomal doxorubicin, and particularly pegylated liposomal doxorubicin, has shown significant pharmacologic advantages and an added clinical value over doxorubicin. Here, we review the mechanisms of action and toxicity of doxorubicin, and ways to reduce toxicity, with a focus on liposome-based drug-delivery systems.

Use of biomarkers for the assessment of chemotherapy-induced cardiac toxicity

OBJECTIVES

To review the evidence for the use of various biomarkers in the detection of chemotherapy associated cardiac damage.

DESIGN AND METHODS

Pubmed.gov was queried using the search words chemotherapy and cardiac biomarkers with the filters of past 10years, humans, and English language. An emphasis was placed on obtaining primary research articles looking at the utility of biomarkers for the detection of chemotherapy-mediated cardiac injury.

RESULTS

Biomarkers may help identify patients undergoing treatment who are at high risk for cardiotoxicity and may assist in identification of a low risk cohort that does not necessitate continued intensive screening. cTn assays are the best studied biomarkers in this context and may represent a promising and potentially valuable modality for detecting cardiac toxicity in patients undergoing chemotherapy. Monitoring cTnI levels may provide information regarding the development of cardiac toxicity before left ventricular dysfunction becomes apparent on echocardiography or via clinical symptoms. A host of other biomarkers have been evaluated for their utility in the field of chemotherapy related cardiac toxicity with intermittent success; further trials are necessary to determine what role they may end up playing for prediction and prognostication in this setting.

CONCLUSIONS

Biomarkers represent an exciting potential complement or replacement for echocardiographic monitoring of chemotherapy related cardiac toxicity which may allow for earlier realization of the degree of cardiac damage occurring during treatment, creating the opportunity for more timely modulation of therapy.

Cardiotoxicity of cisplatin-based chemotherapy in advanced non-small cell lung cancer patients

Cardiotoxicity is a well known consequence of cancer chemotherapy. Cisplatin-based combinations are standard regimens in the therapy of advanced non-small cell lung cancer. Administration of cisplatin-containing chemotherapy causes significant oxidative and nitrosative stress in some patients. Cardiac blood biomarkers can be used to evaluate cardiac status, may help to identify patients at risk myocardial damage evaluation and are able to detect subclinical, early-stage cisplatin-induced cardiotoxicity. The relevance of cardiovascular complications in cancer patients and identification of individual risk factors for developing cardiovascular toxicity merit further evaluation and a longer follow-up is needed.

Cardiotoxicity of childhood cancer treatment: update and current knowledge on long-term follow-up

Therapeutic advances in paediatric oncology allowed increasing numbers of children to survive until adulthood. However, chemotherapy and radiotherapy are potentially cardiotoxic and contribute to a significant morbidity and mortality, cardiovascular events remaining the leading cause of death among survivors. This review summarizes the physiopathology of treatment-related cardiovascular diseases, their incidence, and the risk factors associated with each specific therapy. Few studies have investigated the cardiac outcomes of adult surviving from childhood cancers but all demonstrated a substantial risk for late cardiac effects. Cardiovascular monitoring, prevention, and early detection of cardiac dysfunction are, therefore, the keystones of an improved long-term outcome.

Serial measurements of NT-proBNP are predictive of not-high-dose anthracycline cardiotoxicity in breast cancer patients

Background:

The aim of this study was to assess the value of N-terminal pro-brain natriuretic peptide (NT-proBNP) in predicting late cardiotoxicity in patients treated with not-high-dose chemotherapy (NHDC), and to compare the predictive value of NT-proBNP and cardiac troponin I (cTnI).

Methods:

In 71 patients undergoing NHDC with anthracyclines, NT-proBNP and cTnI levels were measured before and 24 h after each NHDC cycle. Left ventricular (LV) function was assessed by echocardiography at baseline, every two NHDC cycles, at the end of chemotherapy, and at 3-, 6- and 12-month follow-up.

Results:

During NHDC, only NT-proBNP showed abnormal values. According to NT-proBNP behaviour, patients were divided into two groups: group A (n=50) with normal (n=23) or transiently elevated NT-proBNP levels (n=27), and group B (n=21) with persistently elevated NT-proBNP levels. At follow-up, LV impairment was significantly worse in group B than in group A. %Δ (baseline–peak) NT-proBNP was predictive of LV impairment at 3-, 6- and 12-month follow-up, with a cutoff of 36%.

Conclusion:

Serial measurements of NT-proBNP may be a useful tool for the early detection of patients treated with NHDC at high risk of developing cardiotoxicity.

Myocardial protective effect of tezosentan, an endothelin receptor antagonist, for ischemia-reperfusion injury in experimental heart failure models

The myocardial protective effects of endothelin antagonist in ischemic cardiomyopathy (ICMP), doxorubicin-induced cardiomyopathy (DOX) and pressure-overload hypertrophy by transverse aortic constriction (TAC) models have been predicted to be different. The objective of this experiment, therefore, is to evaluate the myocardial protective effect of tezosentan, an endothelin receptor antagonist, in various experimental heart failure models. Sprague-Dawley rats (6-8 weeks old, 200-300 g) were randomized to three experimental groups (n=30 each): ICMP; DOX; and TAC group. Each of these groups was randomly assigned further to the following subgroups (n=10 each): sham-operated ischemia-reperfusion subgroup (SHAM); tezosentan treated ischemia-reperfusion subgroup (Tezo); and tezosentan non-treated ischemia-reperfusion subgroup (N-Tezo). Total circulatory arrest was induced for 1 hr, followed by 2 hr of reperfusion. The left ventricular developed pressure, peak positive and negative first derivatives, and coronary blood flow were significantly different (P<0.05) among the SHAM, Tezo, and N-Tezo subgroups of the ICMP group at 30 min of reperfusion, but there were no statistically significant differences among the subgroups of the DOX and TAC groups. In conclusion, tezosentan, an endothelin receptor antagonist, showed myocardial protection effects only on the ischemic cardiomyopathy rat model, but not in the non-ischemic heart failure rat models.

Troponins and natriuretic peptides in the monitoring of anthracycline cardiotoxicity

Anthracycline-related cardiotoxicity has a substantial negative impact on long-term survivors of childhood cancer. The detection of cardiotoxicity is currently based on echocardiography or radionuclide angiography. However, as they depict only the final outcome of myocardial injury in terms of reduced heart contractility, heart specific biomarkers of myocardial destruction or dysfunction could be advantageous by allowing for an earlier detection of cardiotoxicity. In the present study, the usefulness of cardiac troponins and natriuretic peptides, the most commonly used biomarkers of myocardial destruction and ventricular dysfunction respectively, to detect and to predict the development of anthracycline cardiotoxicity has been reviewed.

Use of cardiac markers to assess the toxic effects of anthracyclines given to children with cancer: a systematic review

AIM

To evaluate the effectiveness of cardiac markers to quantify anthracycline-induced cardiotoxicity in children with cancer.

METHODS

Systematic review using a priori methods.

RESULTS

Seven studies, all with methodological limitations, were identified. One RCT suggests that cardiac troponin can be used to assess the effectiveness of the cardio-protective agent dexrazoxane. Cohort studies suggest that atrial natriuretic peptide and brain (B-type) natriuretic peptide are elevated in some subgroups of patients compared with healthy children; NT-pro-BNP levels are significantly elevated in children with cardiac dysfunction compared with those without; serum lipid peroxide is higher in children who have received doxorubicin compared with children not receiving doxorubicin; there are no differences in carnitine levels between children treated with doxorubicin and a healthy control group.

CONCLUSIONS

The limited evidence makes conclusions difficult. Research is needed to fill this important evidence gap and link short-term changes in cardiac markers to longer-term cardiac damage.

ProANP and NT-proBNP levels to prospectively assess cardiac function in breast cancer patients treated with cardiotoxic chemotherapy

BACKGROUND

Cardiac function impairment is a known side effect of epirubicin-based chemotherapy. Activation of natriuretic peptides is demonstrated in patients with heart failure.

AIMS

To identify prospectively the cardiotoxic profile of epirubicin-based chemotherapy in breast cancer patients and to evaluate the sensitivity of proANP and NT-proBNP as early biochemical markers of cardiac dysfunction.

METHODS

Forty cancer patients divided in two nonrandomized groups received either epirubicin and paclitaxel (Group A, n=26) or mitoxantrone and docetaxel (Group B, n=14). Control groups, Group C (n=13) and Group D (n=20), consisted of female patients with heart failure and healthy women respectively. Natriuretic peptides and LVEF were determined in all patients.

RESULTS

A statistically significant difference was recorded regarding LVEF before and after treatment in Group A patients (p=0.0001). Three patients had a significant LVEF decline between 10% and 18% from baseline values, while three reached an LVEF value below 50%. All of them presented an increase in proANP and NT-proBNP values (mean increase 270.31+/-124 fmol/ml and 303.57+/-108 fmol/ml, respectively). A significant correlation between the increase in plasma proANP (r=0.8, p<0.0001), as well as NT-proBNP (r=0.7, p<0.0001) and the decrease in LVEF was observed. Regarding Group A, levels of proANP increased from 192.25 fmol/ml before treatment to 287.84 fmol/ml after treatment (p=0.0001), whereas NT-proBNP increased from 152.50 to 242 fmol/ml (p<0.0001) respectively. During follow up, two Group A patients developed congestive heart failure twelve and fourteen months after the completion of chemotherapy respectively. A significant LVEF decline was recorded in both patients during the episode. Regarding Group B, no statistically significant differences were demonstrated.

CONCLUSION

ProANP and NT-proBNP levels might be used as reliable and sensitive markers in the detection of early cardiac impairment caused by epirubicin-based chemotherapy.

Anthracycline cardiotoxicity

The use of anthracyclines is limited by dose-dependent cardiotoxicity. Three forms of anthracycline cardiotoxicity are described; an immediate pericarditis-myocarditis syndrome, an early onset chronic progressive CHF developing during or shortly after therapy and late-onset cardiotoxicity presenting years following treatment. A number of risk factors have been reported, including; cumulative dose, administration schedule, mediastinal radiotherapy, old and young age, concurrent cardiovascular disease, combination therapy, gender, ethnicity and chromosomal abnormalities. Evaluation of left ventricular ejection fraction has been widely adopted as a means of monitoring and assessing anthracycline-induced cardiotoxicity. Biochemical markers and other techniques, such as endomyocardial biopsy, metaiodobenzylguanidine and indium-111-antimyosin scintigraphy are not routinely used. Methods employed to prevent cardiotoxicity include cumulative dose limitation, alteration of administration schedule, anthracycline analogues, liposomal formulations and the cardioprotective agent, dexrazoxane. With the growing number of paediatric malignancy survivors and the increasing use of anthracyclines in the adjuvant treatment of breast cancer, the cardiotoxicity associated with these agents will remain a formidable issue for physicians. Further work is required to identify patients at increased risk of cardiotoxicity and to develop novel methods of protecting and treating this adverse effect.

N-Terminal Pro-B-Type Natriuretic Peptide after High-Dose Chemotherapy: A Marker Predictive of Cardiac Dysfunction?

Background: Chronic cardiac dysfunction may develop after administration of aggressive chemotherapy, sometimes leading to development of congestive heart failure (CHF). Recently, N-terminal pro-B-type natriuretic peptide (NT-proBNP) was implicated as a marker of CHF. In this study we evaluated the predictive role of NT-proBNP in patients treated with high-dose chemotherapy (HDC).

Methods: NT-proBNP was measured after 62 chemotherapy treatments in 52 patients affected by aggressive malignancies. Blood samples were drawn before the start of HDC, at the end of HDC administration, and 12, 24, 36, and 72 h thereafter. In these patients, echocardiograms were performed regularly during a 1-year follow-up.

Results: Seventeen patients (33%) had persistently increased NT-proBNP, 19 patients (36%) had only transient increases (concentrations went back to baseline at 72 h), and 16 (31%) had no increases [mean (SD) values at 72 h, 1163 (936) ng/L vs 185 (101) ng/L vs 39 (19) ng/L, respectively; P &lt;0.0001]. Only patients with persistently increased NT-proBNP had a significant worsening of the left ventricular diastolic indexes from baseline to 12 months [ratio of peak early to peak late flow velocities from 1.42 (0.33) to 0.78 (0.11); P &lt;0.0001; isovolumetric relaxation time from 90 (15) to 141 (26) ms; P &lt;0.0001; E-wave deceleration time from 162 (17) to 224 (32) ms; P = 0.0004] and of the left ventricular ejection fraction [from 62.8 (3.4)% to 45.6 (11.5)%; P &lt;0.0001].

Conclusions: Persistently increased NT-proBNP early after administration of HDC is strongly associated with development of cardiac dysfunction. This finding has important implications for identifying patients at risk of developing chemotherapy-induced cardiotoxicity.

Natriuretic peptides in the monitoring of anthracycline induced reduction in left ventricular ejection fraction

BACKGROUND

The use of anthracyclines in treatment of cancer is limited by cardiotoxicity of these compounds and may lead to heart failure. Therefore monitoring of cardiac function is necessary during therapy.

AIM

We evaluated the value of natriuretic peptides (N-terminal pro-atrial natriuretic peptide (N-ANP) and brain natriuretic peptide (BNP)) for monitoring and predicting anthracycline induced cardiotoxicity using radionuclide left ventricular ejection fraction (EF) measurements as reference.

METHODS AND RESULTS

A total of 107 consecutive patients receiving anthracycline as part of their chemotherapy for malignant disease were studied. Plasma concentrations of the peptides were measured by radioimmunoassay and EF by radionuclide cardiography. For reduced EF values, i.e. below 0.50 a fairly strong correlation was found between N-ANP or BNP and EF. Of 48 patients with serial EF and peptide measurements, 19% showed a significant EF decrease (>0.10) and ended with a final EF value below 0.50. Baseline EF was no predictor of a change in EF during treatment. Neither baseline levels of N-ANP or BNP nor a change in the same variables during therapy were predictive of a change in EF.

CONCLUSIONS

In spite of correlations between peptide concentrations and reduced EF values neither baseline values nor serial measurements can safely substitute EF monitoring in patients undergoing anthracycline therapy.

Early decline in left ventricular ejection fraction predicts doxorubicin cardiotoxicity in lymphoma patients

Thirty adult patients with non-Hodgkin's lymphoma were studied to evaluate prospectively the significance of early decline in left ventricular ejection fraction after low cumulative doxorubicin dose (200 mg x m(-2)) in predicting the later impairment of left ventricular function. Cardiac function was monitored with radionuclide ventriculography at baseline and after cumulative doxorubicin doses of 200, 400 and 500 mg x m(-2). Cardiotoxicity was defined as a decrease in left ventricular ejection fraction of more than 10% units to a final left ventricular ejection fraction < or =50%. Twenty-eight patients received doxorubicin > or =400 mg x m(-2) and were evaluable for cardiotoxicity. Clinical heart failure developed in two patients (7%) after a cumulative doxorubicin dose of 500 mg m(-2). Left ventricular ejection fraction decreased more than 10% absolute ejection fraction units to a final left ventricular ejection fraction < or =50% in 10 patients (36%). Left ventricular ejection fraction decreased from 56+/-1.5% to 53.6+/-1.5% (P=0.016) in patients with no cardiotoxicity, and from 60.8+/-2.4% to 41.8+/-2.0% (P<0.001) in patients with cardiotoxicity. For patients who developed cardiotoxicity, the fall in left ventricular ejection fraction after a cumulative doxorubicin dose of only 200 mg x m(-2) was highly significant (left ventricular ejection fraction 49.7+/-1.8%, P=0.001 vs baseline). In receiver operator characteristic analysis, the area under the curve for the decrease in left ventricular ejection fraction at a cumulative doxorubicin dose of 200 mg x m(-2) for predicting cardiotoxicity in all patients was 0.858. The decrease in left ventricular ejection fraction of more than 4% units after a cumulative doxorubicin dose of 200 mg x m(-2) had a 90% sensitivity and 72% specificity for predicting later cardiotoxicity. Our results show that the significant impairment of left ventricular function during doxorubicin therapy can be predicted early, already at low cumulative doxorubicin doses. This finding may be of value in identifying patients at high or low risk for the development of anthracycline cardiotoxicity.

Chemotherapy-induced cardiotoxicity: current practice and prospects of prophylaxis

Cardiotoxicity is a potential side effect of few chemotherapeutic agents. The anthracycline class of cytotoxic antibiotics are the most famous, but other chemotherapeutic agents can also cause serious cardiotoxicity and are not so well recognised. Examples include cyclophosphamide, ifosfamide, mitomycin and fluorouracil. Prediction and hence prophylaxis has always been a difficult task. Ideal monitoring techniques, upon which efficient prophylaxis depends, are yet to be determined. Current prophylaxis relies upon early detection of systolic and/or diastolic dysfunction. While somewhat useful, in some cases by the time defects are detected progression of chemotherapy-induced cardiomyopathy is beyond prevention. Prophylaxis would be much more efficient if a biochemical marker of myocardiocyte damage could be reliably used to stop further chemotherapy at the correct time before irreversible progressive 'macroscopic' damage becomes evident upon imaging. Work is currently progressing to identify the role of markers such as troponins and natriuretic peptides in this regard.

BNP and congestive heart failure

Brain natriuretic peptide (BNP), a peptide hormone secreted chiefly by ventricular myocytes, plays a key role in volume homeostasis. The plasma concentration of BNP is raised in various pathological states, especially heart failure. Many studies suggest that measurement of plasma BNP has clinical utility for excluding a diagnosis of heart failure in patients with dyspnea or fluid retention and for providing prognostic information in those with heart failure or other cardiac disease. It may also be of value in identifying patients after myocardial infarction in whom further assessment of cardiac function is likely to be worthwhile. Preliminary evidence suggests that measuring the plasma concentration of BNP may be useful in fine tuning therapy for heart failure. Artificially raising the circulating levels of BNP shows considerable promise as a treatment for heart failure. With simpler assay methods now available, it is likely that many physicians will measure plasma BNP to aid them in the diagnosis, risk stratification, and monitoring of their patients with heart failure or other cardiac dysfunction.

Plasma levels of natriuretic peptides in relation to doxorubicin-induced cardiotoxicity and cardiac function in children with cancer

BACKGROUND

Anthracyclines are effective anticancer drugs for childhood cancer with dose-limiting cardiotoxicity. Children who have received anthracyclines thus need periodical cardiac evaluation. The plasma levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) have been shown to increase in proportion to severity of cardiac dysfunction. We examined whether plasma levels of ANP and BNP, in addition to echocardiographic evaluation, can be used as specific markers for doxorubicin-induced cardiotoxic effects in children.

PROCEDURE

Consecutively, 34 patients (18 boys and 16 girls) who had previously received doxorubicin-containing chemotherapy were enrolled in this study. Plasma ANP and BNP were assayed simultaneously at the time of first cardiac function evaluation by echocardiography.

RESULTS

Of the 34 patients, 8 (23.5%) had left ventricular dysfunction as assessed by echocardiography. Both ANP and BNP plasma levels in these patients were significantly elevated in comparison with healthy controls (P < 0.01) or patients with normal cardiac function (P < 0.05). It should be also noted that ANP and BNP levels were correlated significantly with cardiac systolic function, but not with diastolic function.

CONCLUSIONS

These results suggest that plasma ANP and BNP levels could be markers for doxorubicin-induced cardiotoxicity in children. Measurement of natriuretic peptide levels during treatment may allow earlier-identification of individuals at risk for severe cardiac damage.

Effects of dose-intensive chemotherapy and radiotherapy on serum n-terminal proatrial natriuretic peptide in high-risk breast cancer patients

By using N-terminal proatrial natriuretic peptide (proANP) in serum as a marker of cardiac function, we compared the cardiac side effects of two intensive adjuvant treatment regimens for breast cancer. Patients received either 9 cycles of FEC (5-fluorouracil, epirubicin and cyclophosphamide) where the doses of epirubicin and cyclophosphamide were escalated according to the leucocyte nadir (n = 49, FEC-group) or three cycles of FEC followed by high-dose chemotherapy with alkylating agents (n = 56, CTCb-group) given with the support of peripheral blood stem cells support. Both groups received adjuvant radiotherapy. Serial measurements of proANP were performed up to three years after treatment. Mean proANP values in the FEC-group was on average 19% higher than in the CTCb-group (p = 0.002). The proANP levels showed a significant association with the cumulative dose of epirubicin (p < 0.001) but not with cyclophosphamide (p = 0.151) and 5-FU (p = 0.160). The pharmacokinetics of epirubicin was studied at the first and third chemotherapy course. The proANP levels after treatment were significantly related to the AUC (p = 0.034) and Cmax(p = 0.037) of epirubicin. Left-sided chest irradiation was associated with on average 12% higher proANP values than right-sided (p = 0.031). We conclude that dose-escalated FEC causes a stronger increase in proANP than 3 FEC followed by high-dose CTCb-treatment. Increase of proANP levels might represent an early sign of cardiotoxicity secondary to chemotherapy and radiation treatment. Long-time follow-up is necessary to determine the clinical significance of these findings.

Prospective Evaluation of Early Cardiac Damage Induced by Epirubicin-Containing Adjuvant Chemotherapy and Locoregional Radiotherapy in Breast Cancer Patients

PURPOSE: To evaluate prospectively the cardiotoxic effects of epirubicin-containing adjuvant chemotherapy in breast cancer patients.

PATIENTS AND METHODS: Patients (median age, 46 years; range, 28 to 55 years) were treated with five cycles of fluorouracil, epirubicin (90 mg/m2), and cyclophosphamide (FEC) (group I, n = 21) or with four cycles of FEC followed by high-dose chemotherapy consisting of cyclophosphamide, thiotepa, and carboplatin (group II, n = 19). Locoregional radiotherapy was applied subsequently. Cardiac evaluation was performed before chemotherapy (T0), 1 month after chemotherapy, 1 month after radiotherapy (T2), and 1 year after start of chemotherapy (T3). Left ventricular ejection fraction (LVEF) was determined by radionuclide ventriculography and diastolic function by echocardiography. Autonomic function was assessed by 24-hour ECG registration for heart rate variability (HRV) analysis. Time-corrected QT (QTc) was assessed and N-terminal atrial natriuretic peptide (NT-ANP) and brain natriuretic peptide (BNP) were measured as biochemical markers of cardiac dysfunction.

RESULTS: No patient developed overt congestive heart failure (CHF) and the mean LVEF declined from 0.61 at T0 to 0.54 at T3 (P = .001), resulting in an LVEF below 0.50 (range, 0.42 to 0.49) in 17% of the patients, whereas 28% had a decline of more than 0.10. Plasma NT-ANP levels increased gradually from 237 pmol/L at T0 to 347 pmol/L at T3 (P < .01), whereas plasma BNP levels increased from 2.9 pmol/L to 5.1 pmol/L (P = .04). Mean QTc increased from 406 msec at T0 to 423 msec at T3 (P < .01). No persistent alterations were found in diastolic function and HRV.

CONCLUSION: Relatively low doses of epirubicin in adjuvant chemotherapy for breast cancer results in mild subclinical myocardial damage demonstrated by a decline in LVEF, an increase in natriuretic peptide levels, and an increase in QTc, which may indicate a long-term risk of CHF.

Assessment of cardiotoxicity during haemopoietic stem cell transplantation with plasma brain natriuretic peptide

Cardiac failure is a known complication of haemopoietic stem cell transplantation (HSCT) and is often difficult to diagnose as patients may have multiple medical problems. Since brain natriuretic peptide (BNP) is largely a hormone of cardiac ventricular origin and is released early in the course of ventricular dysfunction, we have examined the value of serial plasma BNP levels for detecting cardiac failure in patients undergoing cytotoxic conditioning for HSCT. Fifteen patients undergoing HSCT were evaluated (10 undergoing autologous HSCT; five undergoing allogeneic HSCT). BNP was measured by radioimmunoassay prior to therapy and weekly for 5 weeks. Seven patients had a significant rise in BNP level (above a previously established threshold of 43 pmol/l associated with cardiac failure), occurring 1-4 weeks post commencement of conditioning. In three of these patients, cardiac failure was subsequently diagnosed clinically 3, 9 and 23 days after a BNP level of 43 pmol/l had been detected. These three patients had the highest peak BNP levels for the group and in each case elevation in BNP level occurred for a period exceeding 1 week. Although numbers were relatively small, a BNP >43 pmol/l was significantly associated with the inclusion of high-dose cyclophosphamide in the preparative regimen (P = 0.02). BNP levels showed no relationship to febrile episodes. In conclusion, these results show that plasma BNP may be used as a marker for early detection of cardiac dysfunction in patients undergoing HSCT, particularly if levels are increased for periods exceeding 1 week. Measurement of BNP during HSCT may be helpful in patients at risk of cardiac failure, in complex clinical situations and in monitoring the cardiotoxicity of preparative regimens.

Plasma levels of N-terminal proatrial natriuretic peptide in children are dependent on renal function and age

Plasma levels of natriuretic peptides are used as diagnostic markers of heart failure. The aim of this study was to analyse the relation between plasma levels of N-terminal proatrial natriuretic peptide (Nt-proANP) and renal function, and to develop reference values in children. Nt-proANP was measured in the plasma of 86 patients whose glomerular filtration rate (GFR) was determined by use of the X-ray contrast medium iohexol and a fluorescence technique. Blood samples for Nt-proANP were also collected in 399 reference children, aged 0 - 15 years. The relationship between Nt-proANP and GFR was examined using a multiple regression analysis. The mean value of Nt-proANP was markedly higher in children with heart failure than in children with malignant or urologic diseases (p<0.001). The variability in plasma levels of Nt-proANP was mainly (adjusted R2=0.81) explained by the following four variables: presence of heart failure, GFR, age and previous treatment with anthracyclins. Plasma levels of the peptide are raised at birth, but fall rapidly to adult levels. We conclude that the plasma levels of Nt-proANP are age-dependent. Moderately elevated values were registered in children with severe renal impairment. Heart failure is regularly associated with excessive elevation of Nt-proANP in plasma. Our findings suggest that the influence of heart failure on levels of this peptide in children greatly exceeds the influence of renal dysfunction.

Doxorubicin selectively inhibits brain versus atrial natriuretic peptide gene expression in cultured neonatal rat myocytes

Doxorubicin is an antineoplastic agent with significant cardiotoxicity. We examined the effects of this agent on the expression of the natriuretic peptide (NP) genes in cultured neonatal rat atrial myocytes. Doxorubicin suppressed NP secretion, steady-state NP mRNA levels, and NP gene promoter activity. In each instance, brain NP (BNP) proved to be more sensitive than atrial NP (ANP) to the inhibitory effects of the drug. ICRF-187 and probucol reversed the inhibition by doxorubicin of ANP mRNA accumulation and ANP gene promoter activity while exerting no effect on BNP mRNA levels or promoter activity. This represents the first identification of the NP genes as targets of doxorubicin toxicity in the myocardial cell. This inhibition operates predominantly at a transcriptional locus and has more potent effects on BNP versus ANP secretion/gene expression. Measurement of BNP secretion/gene expression may provide a sensitive marker of early doxorubicin cardiotoxicity.

Detection of anthracycline-induced cardiotoxicity

The use of anthracyclines, a group of potent anti-cancer agents incorporated into the treatment of a wide variety of solid and haematological tumours, is limited by its cardiotoxicity that can result in congestive heart failure (CHF). The best method to detect cardiotoxicity at an early stage in order to prevent severe deterioration, is still an unsolved problem. Although endomyocardial biopsy is considered to be the most sensitive and specific test for this purpose, its use is limited by its invasiveness. In daily practice, oncologists make use of parameters of systolic function (left ventricular ejection fraction, or fractional shortening) to detect cardiotoxicity, but these methods are not able to identify cardiotoxicity at an early stage. Based on increasing knowledge into the pathophysiology of anthracycline-induced cardiotoxicity and heart failure in general, new methods including the determination of diastolic function parameters, anti-myosin scintigraphy, assessment of heart rate variability, and the determination of biochemical markers have been proposed to identify patients at risk of the development of CHF in an early stage. However, most of these newer methods have not yet been adequately evaluated to allow them to be recommended for use in routine clinical practice.

Persistent effects of doxorubicin on cardiac gene expression

During administration of the anthracycline antitumour agents, their cardiotoxicity can progress from cardiac dysfunction to heart failure. Cardiomyopathy can also develop years after receiving anthracyclines. To determine if persistent and/or progressive anthracycline effect(s) are referable to anthracycline effects on cardiac gene expression, steady-state mRNA levels were determined 4 days (n=8), 4 weeks (n=7) and 10 weeks (n=7) after doxorubicin (DOX; 2 mg/kg IV) in a well-characterized rabbit model. Levels of mRNA for alpha -actin, beta -myosin heavy chain and the calcium pump of the sarcoplasmic reticulum (SERCA2a) in the left ventricle (LV) were determined by Northern blot hybridization and expressed relative to an 18S constitutive marker. The mRNA levels for the high molecular weight subunit (cardiac isoform) of the ryanodine receptor (RyR2), sarcolemmal calcium channel (dihydropyridine receptor; DHPR), angiotensin-converting enzyme (ACE), angiotensin II receptor (ATR) and atrial naturetic peptide prohormone (ANP) were determined by reverse transcription-polymerase chain reaction (RT-PCR) and Southern blot analysis, and expressed relative to GAPDH, a constitutive marker. Histopathologic evidence for anthracycline-induced myocardial cell injury was absent (score <1) in all hearts examined except one (score=1.1; 4 weeks post-DOX), which was considered separately. Relative mRNA levels for beta -myosin heavy chain 4 days after DOX increased 1.9-fold compared to the vehicle-treated group, but by 4 weeks levels had returned to baseline. Relative mRNA levels for DHPR were increased 1.2-fold 4 days after DOX and were persistently increased 1.9- and 2.2-fold 4 and 10 weeks after DOX, respectively. The mRNA levels for ANP were first decreased (4.5-fold) 4 days after DOX. Four weeks after DOX, ANP message levels approached Control in seven out of eight rabbits. The one rabbit with early LV histopathology 4 weeks post-DOX had increased mRNA for DHPR (2.7-fold) and ANP (80-fold). Between 4 and 10 weeks after DOX, mRNA levels for ANP increased C 16-fold: evidence for late progression. In situ hybridization with specific riboprobes localized the persistent increase in DHPR and the progressive increase in ANP to myocytes. Thus, DOX alters steady-state mRNA levels in LV that are referable to both persistent and progressive anthracycline effects on myocellular gene expression.

Natriuretic peptides as markers of cardiotoxicity during doxorubicin treatment for non-Hodgkin's lymphoma

Thirty adult patients with non-Hodgkin's lymphoma who were planned to receive up to 8-10 cycles of CHOP (cyclophosphamide, doxorubicin, vincristine and prednisolone) to a cumulative doxorubicin dose of 400-500 mg/m2 were studied to evaluate the value of serial plasma atrial natriuretic peptide (ANP), N-terminal pro-ANP (NT-proANP) and brain natriuretic peptide (BNP) measurements in the early detection of doxorubicin-induced left ventricular dysfunction. Plasma levels of natriuretic peptides were measured before every treatment course and 4 wk after the last one. Cardiac function was monitored with serial radionuclide ventriculography. Twenty-eight patients were evaluable for cardiotoxicity. Clinical heart failure developed in 2 patients (7%). Left ventricular ejection fraction (LVEF) decreased from 58.0+/-1.3% to 49.6+/-1.7% (p <0.001). Plasma levels of ANP increased from 16.4+/-1.3 pmol/l to 22.7+/-2.4 pmol/l (p= 0.002), NT-proANP from 288+/-22 to 380+/-42 pmol/l (p = 0.019) and BNP from 3.3+/-0.4 to 8.5+/-2.0 pmol/l (p = 0.020). There was a significant correlation between the increase in plasma ANP and the decrease in LVEF (r = -0.447, p = 0.029), and a trend towards significance between the increase in NT-proANP and the decrease in LVEF (r=-0.390, p=0.059). The decrease in LVEF started very early and could already be seen after the cumulative doxorubicin dose of 200 mg/m2, whereas the increase in plasma natriuretic peptides was not evident until the cumulative doxorubicin dose of 400 mg/m2. Our results show that neuroendocrine activation - increased concentrations of plasma natriuretic peptides - occurs when left ventricular function has reduced substantially and its compensatory capacity has been exceeded resulting in atrial and ventricular overload. Thus, serial natriuretic peptide measurements cannot be used in predicting the impairment of left ventricular function. On the other hand, our study suggests that natriuretic peptides are useful in the detection of subclinical left ventricular dysfunction in patients receiving doxorubicin therapy.

Acute neurohumoral and cardiovascular effects of idarubicin in leukemia patients

Idarubicin has been shown to have similar or superior antileukemic activity to daunorubicin with less cumulative cardiotoxicity. However, data of acute cardiovascular effects of idarubicin are scanty but may have clinical significance in predicting late cardiovascular complications. In the present study we evaluated prospectively acute neurohumoral and cardiovascular effects of idarubicin containing induction chemotherapy in 10 patients with newly diagnosed AML or MDS. Idarubicin was administered intravenously 12 mg/m2 on d 1, 3 and 5 as a part of the induction chemotherapy. Serial measurements of plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) were performed at baseline and the day following each idarubicin infusion. Echocardiography was performed to assess cardiac systolic and diastolic function. Signal averaged electrocardiography (ECG) was recorded to observe myocardial late potentials associated with possible myocardial injury. In addition, ambulatory ECG recording was performed to assess arrhythmias. Plasma concentrations of ANP increased from 18.2 +/- 1.5 pmol/l to 27.8 +/- 3.5 pmol/l (p = 0.011), to 30.2 +/- 3.0 pmol/l (p = 0.002) and to 40.8 +/- 6.0 pmol/l (p = 0.006) after the first, second and third doses of idarubicin, respectively. Similarly, plasma concentration of BNP increased from 6.2 +/- 1.9 to 9.0 +/- 1.8 pmol/l (p = 0.049) and 17.5 +/- 8.1 pmol/l (p = 0.203) after the first and third idarubicin infusion. Concomitantly, there was a trend towards an increase in left ventricular end diastolic diameter (LVEDD) (50.2 +/- 1.8 to 54.4 +/- 2.2 mm, p = 0.070). The increase in plasma BNP concentrations correlated significantly with the increase in LVEDD (r = 0.624; p = 0.002). No significant ECG changes or arrhythmias were associated with idarubicin infusions except in 1 patient who developed abnormal myocardial late potentials. Our results show that idarubicin causes acute neurohumoral activation associated with increased LVEDD indicating subclinical myocardial dysfunction. Whether these acute changes predict late clinical cardiomyopathy should be evaluated in prospective studies with larger number of patients and with higher cumulative anthracycline doses.

Serum N-terminal atrial natriuretic peptide (NT-ANP) in the cardiac follow-up in children with cancer

BACKGROUND

We studied serum N-terminal atrial natriuretic peptide (NT-ANP) in children during and after chemotherapy for cancer to determine its applicability in detecting cardiac dysfunction. Forty-three patients were receiving chemotherapy for malignancy. Forty-eight patients were off chemotherapy and survived between 0.9 and 13 (median 5) years after the diagnosis, receiving cumulative anthracycline doses between 0 and 600 (median 225) mg/m2.

PROCEDURE AND RESULTS

Cardiac evaluation of the patients included measurement of serum NT-ANP, recording of ECG, and assessment of systolic and diastolic function of the heart by echocardiography. During chemotherapy, serum NT-ANP levels were higher than in controls but varied markedly in the same individuals. Serum NT-ANP levels showed no consistent increase in the weeks following anthracycline administration. In late follow-up, serum NT-ANP levels were higher than in age-matched controls (median (range), 0.22 (0.06-0.47) vs. 0.14 (0.06-0.27) nmol/l, respectively, P < .001). The subgroup of patients with bone marrow transplantation and/or cardiac irradiation had the highest NT-ANP concentrations (0.30 (0.20-0.45) nmol/l).

CONCLUSIONS

Thus, serum NT-ANP measurements seemed to represent a useful contribution in the long-term cardiac follow-up of children after cancer. This blood test can readily be included to laboratory follow-up, is reasonably inexpensive and may decrease the need for more laborious tests of cardiac function. When there is ongoing chemotherapy, NT-ANP levels are influenced by a variety of factors that invalidate its routine use during this period.

[Heart pathology of extracardiac origin. VII. Heart and neoplasms]

Cardiac alterations of neoplastic diseases can be due to direct invasion produced by primary cardiac tumors or more frequently secondary to local compression of vascular structures by extracardiac neoplasms, such as superior vena cava syndrome. One of the most important alterations is the cardiotoxicity of anticancer treatments, either chemotherapy drugs or radiotherapy techniques. These treatments cause acute and/or chronic cardiotoxicity that the oncologist and the cardiologist must be aware of. For instance, 4.5% to 7% of patients that have been treated with anthracyclines may suffer cardiac failure in their lifetime. The pathogenesis is still not clear. There is currently a lot of research on cardioprotectors, but nowadays the only one approved by the FDA is dexrazoxane, which is used on breast cancer patients treated with adriamycin.

Plasma endothelin-1 as a marker for doxorubicin cardiotoxicity

The use of doxorubicin is often limited by cardiotoxicity that can lead to congestive heart failure (CHF). Although various techniques have been used to predict its cardiotoxicity, none has proven useful. We reported 2 patients in whom the level of plasma endothelin (ET)-1 rose progressively during doxorubicin treatment of breast cancer, and who subsequently developed CHF. Accordingly, we conducted a prospective study of 30 consecutive patients, 23 with breast cancer and 7 with small-cell lung cancer, who were treated with doxorubicin. Serial changes in plasma ET-1 during doxorubicin treatment were measured by a specific radioimmunoassay, and plasma levels of atrial natriuretic peptide (ANP) were determined by a sensitive immunoradiometric assay. M-mode echocardiography was performed serially to monitor the fractional shortening (FS) and the left ventricular ejection fraction (LVEF). The plasma concentrations of ET-1 rose progressively in 5 of the 30 patients during doxorubicin treatment. Two of the 5 patients developed clinically overt CHF after developing cumulative doses of doxorubicin of 500 and 480 mg/m2. Serial measurement of plasma levels of ANP, FS and LVEF showed no abnormalities until the development of CHF. Another 25 patients who had received doxorubicin (cumulative doses ranging from 400 to 660 mg/m2) and had not developed CHF showed no appreciable change in plasma ET-1 or other markers. This prospective study suggests that plasma ET-1 may be useful for predicting the risk of doxorubicin-induced cardiotoxicity.

Secretion of atrial natriuretic peptide and vasopressin by small cell lung cancer

BACKGROUND

Hyponatremia in patients with small cell lung cancer (SCLC) is a common clinical problem usually attributed to tumor secretion of arginine vasopressin (AVP). It recently was shown that some SCLC cell lines produce atrial natriuretic peptide (ANP). The purpose of this investigation was to determine the frequency and clinical consequences of secretion of ANP by SCLC and the relative contribution of ANP and AVP to the hyponatremia associated with this disease.

METHODS

Levels of ANP and AVP were measured in 23 SCLC cell lines and 23 other human tumor cell lines. Also, ANP and AVP levels were determined in plasma samples from 69 patients with active small cell carcinomas.

RESULTS

Of the 23 SCLC lines, 16 (70%) had elevated ANP levels. Only two (8.7%) had elevated AVP levels, and these two also had elevated ANP levels. One of the ANP-producing cell lines was derived from a hyponatremic patient with no other apparent explanation for a low sodium level. However, the four cell lines with the highest levels of ANP were derived from patients who were not hyponatremic. Two other human tumor lines also produced ANP. Of the 69 patients with SCLC, 21 (30.4%) had elevated ANP levels, whereas 4 (6%) had elevated AVP levels. Fifteen of these patients were hyponatremic during their clinical course (21.7%). Of the eight patients who were hyponatremic when samples were collected, two had elevated ANP levels, and only one had elevated AVP levels. Six patients (8.7%) had symptoms of postural hypotension, possibly attributable in some cases of tumor secretion of ANP.

CONCLUSIONS

The majority of SCLC lines produce ANP, and a minority produce AVP. Secretion of ANP may result in hyponatremia and/or postural hypotension. However, secretion of either or both of these peptides does not account for all cases of hyponatremia in patients with SCLC and does not necessarily cause clinical manifestations.