Assessment of cardiotoxicity with cardiac biomarkers in cancer patients

Cardiotoxicity remains a major limitation of chemotherapy, strongly affecting the quality of life and the overall survival of cancer patients, regardless of their oncologic prognosis. The time elapsed from the end of cancer therapy to the beginning of heart failure therapy for chemotherapy-induced cardiac dysfunction is an important determinant of the extent of recovery. This highlights the need for a real-time diagnosis of cardiac injury. The current standard for monitoring cardiac function detects cardiotoxicity only when a functional impairment has already occurred, precluding any chance of preventing its development. In the last decade, early identification, assessment, and monitoring of cardiotoxicity, by measurement of serum cardiospecific biomarkers, have been proposed as an effective alternative. In particular, the role of troponin I in identifying patients at risk for cardiotoxicity and of angiotensin-converting enzyme inhibitors in preventing left ventricular ejection fraction reduction and cardiac events has clearly proved to be an effective strategy for this complication. In addition, novel biomarkers for the identification of cardiotoxicity are emerging. The use of a multimarker approach may provide a unique opportunity for advancement in this field, allowing for better stratification of the cardiac risk in cancer patients treated with anticancer drugs.     

State of the art review: Chemotherapy‐induced cardiotoxicity in children

Chemotherapy‐induced cardiotoxicity in adults and children is a topic with a growing interest in the cardiology literature. The ability to detect cardiac dysfunction in a timely manner is essential in order to begin adequate treatment and prevent further deterioration. This article aims to provide a review on the myocardial injury process, chemotherapeutic agents that lead to cardiotoxicity, the definition of cardiotoxicity, and the methods of timely detection and treatment.     

Serum cardiac troponin I levels and ECG/Echo monitoring in breast cancer patients undergoing high-dose (7 g/m(2)) cyclophosphamide

High-dose cyclophosphamide (HD-CTX) is largely employed in high-dose chemotherapy (HD-CHT) protocols. HD-CTX dose-limiting toxicity expresses itself as cardiac toxicity which is fatal in a minority of patients. The pathophysiology of HD-CTX-associated cardiotoxicity is still poorly understood. Autopsy studies in patients who died from acute HD-CTX-induced cardiac toxicity revealed hemorrhagic myocardial cell death and interstitial edema. Recently troponins, in particular troponin I (cTnI), have been found to represent a uniquely sensitive and specific marker of myocyte membrane integrity and therefore to increase in response to minimal myocardial cell damage in different settings, including doxorubicin-induced cardiotoxicity. We performed a multiparametric cardiologic monitoring in 16 consecutive breast cancer patients undergoing HD-CTX by means of serial ECG registrations and cardiac enzymes (CPK, CPK-MB and cTnI) determinations plus echocardiography in order to clarify acute cardiac events following HD-CTX administration. Neither overt cardiac toxicity nor cardiac enzymes elevation were recorded. Serial ECGs revealed in six cases little and reversible reduction of QRS voltage and/or ST abnormalities. Echo monitoring showed in four cases mild and transient increase of LV diastolic/systolic diameter/volume without decrease of FS% or EF% below normal values: in two of them abnormalities of diastolic function (E/A mitral doppler ratio) were also recorded. We conclude that our protocol of HD-CTX administration does not cause myocardial cell damage as analyzed by serum cTnI levels, thus suggesting that myocyte membrane injury may not be the first direct mechanism of HD-CTX cardiotoxicity. ECG (ie QRS voltages ) and Echo (ie E/A ratio) monitoring leads us to hypothesize that slight interstitial edema with reduction of LV diastolic compliance may be initial signs of cardiac dysfunction in this clinical setting.     

Toll-Like Receptors and Myocardial Ischemia/Reperfusion, Inflammation, and Injury

Cardiac ischemia/reperfusion (I/R) injury occurs in several important clinical contexts including percutaneous coronary interventions for acute myocardial ischemia, cardiac surgery in the setting of cardiopulmonary bypass, and cardiac transplantation. While the pathogenesis of I/R injury in these settings is multifactorial, it is clear that activation of the innate immune system and the resultant inflammatory response are important components of I/R injury. Toll-like receptor 4 (TLR4), originally identified as the sensor for bacterial lipopolysaccharide (LPS), has also been shown to serve as a sensor for endogenous molecules released from damaged or ischemic tissues. Accordingly, recent findings have demonstrated that TLR4 not only plays a central role as a mediator of cardiac dysfunction in sepsis, but also serves as a key mediator of myocardial injury and inflammation in the setting of I/R. Furthermore, TLR4 may play a role in the development of atherosclerotic lesions. Other studies have implicated TLR4 in the adverse remodeling that may occur after ischemic myocardial injury. This emerging body of literature, which is reviewed here, has provided new insight into the early molecular events that mediate myocardial injury and dysfunction in the setting of I/R injury.     

Early anthracycline cardiotoxicity

Eight patients in whom cardiac dysfunction developed within four weeks of receiving their first or second course of daunorubicin or doxorubicin are described. Four patients presented with pericarditis; three of these four had evidence of myocardial dysfunction. Histopathologic analysis of these patients was consistent with an acute myocyte damage and secondary inflammatory process. An additional group of four patients presented with symptoms and signs of heart failure. These patients were either elderly or had evidence of previous cardiac disease. One of these patients suffered a myocardial infarction 24 hours after receiving 60 mg/m² of daunorubicin; earlier doses in the same course had been associated with evidence of myocardial ischemia. We conclude that anthracycline antibiotics may manifest clinically significant cardiotoxicity at total cumulative doses much less than have been associated with chronic cardiomyopathy.     

Pathophysiology and diagnosis of cancer drug induced cardiomyopathy

The clinical manifestations of anti-cancer drug associated cardiac side effects are diverse and can range from acutely induced cardiac arrhythmias to Q–T interval prolongation, changes in coronary vasomotion with consecutive myocardial ischemia, myocarditis, pericarditis, severe contractile dysfunction, and potentially fatal heart failure. The pathophysiology of these adverse effects is similarly heterogeneous and the identification of potential mechanisms is frequently difficult since the majority of cancer patients is not only treated with a multitude of cancer drugs but might also be exposed to potentially cardiotoxic radiation therapy. Some of the targets inhibited by new anti-cancer drugs also appear to be important for the maintenance of cellular homeostasis of normal tissue, in particular during exposure to cytotoxic chemotherapy. If acute chemotherapy-induced myocardial damage is only moderate, the process of myocardial remodeling can lead to progressive myocardial dysfunction over years and eventually induce myocardial dysfunction and heart failure. The tools for diagnosing anti-cancer drug associated cardiotoxicity and monitoring patients during chemotherapy include invasive and noninvasive techniques as well as laboratory investigations and are mostly only validated for anthracycline-induced cardiotoxicity and more recently for trastuzumab-associated cardiac dysfunction.     

Monitoring of cardiac function by serum cardiac troponin T levels,ventricular repolarisation indices,and echocardiography after conditioning with fractionated total body irradiation and high-dose cyclophosphamide

OBJECTIVES: Highly differing rates of cardiac complications associated with high-dose cyclophosphamide (CY) have been reported, and only one clinical study has been performed on the cardiotoxic effects of CY monotherapy following total body irradiation (TBI). PATIENTS AND METHODS: We prospectively evaluated the potential cardiotoxic effects of conditioning with fractionated total body irradiation and high-dose cyclophosphamide (TBI/CY) by serial measurement of serum cardiac troponin T (cTnT), assessment of systolic and diastolic echocardiographic parameters and analysis of ventricular repolarisation indices (QT-dispersion and corrected QT-dispersion) in 30 adult patients with haematological malignancies undergoing haematopoietic stem cell transplantation. RESULTS: There was no evidence of pretreatment cardiac dysfunction in any patient. Although cTnT was determined serially for a median of 14 d after completion of conditioning, no elevated levels were observed. Echocardiographic parameters did not show any significant change at a median follow-up of 5 months except for one patient with evidence of impaired diastolic filling. No significant differences for mean values before and after high-dose CY were noted for ventricular repolarisation indices. Two patients had a significant increase in corrected QT-dispersion after CY without any other signs of cardiotoxicity. Congestive heart failure or arrhythmias were not observed. CONCLUSIONS: These data suggest that TBI/CY is safe with respect to cardiotoxicity in patients without pre-existing cardiac dysfunction. Hitherto unknown synergistic cardiotoxic effects of CY with other cytostatic drugs may constitute the major pathogenic factor of myocardial dysfunction after high-dose chemotherapy.     

Mechanisms of Anthracycline Cardiotoxicity and Strategies to Decrease Cardiac Damage

Anthracyclines are common chemotherapeutic agents used to treat many different types of cancer. Unfortunately, the use of anthracyclines is limited by their cardiotoxic effects, which may become manifest as late as 20 years from initial exposure. Studies in cells and animals suggest that the mechanism of anthracycline-induced cardiotoxicity (AIC) is multifactorial. Anthracyclines induce multiple forms of cellular injury by free radical production. In addition, anthracyclines alter nucleic acid biology by intercalation into DNA and modulate intracellular signaling, leading to cell death and the disruption of homeostatic processes such as sarcomere maintenance. In an effort to decrease AIC, many strategies have been tested, but no specific therapies are universally acknowledged to prevent or treat anthracycline-induced cardiac dysfunction. Newer imaging modalities and cardiac biomarkers may be useful in improving early detection of cardiac injury and dysfunction. As long as there is no cardiac-specific therapy for AIC, evidence suggests that high-risk patients will benefit from prophylactic treatment with neurohormonal blockade by angiotensin-converting enzyme inhibitors and beta-adrenergic receptor blockers.     

Cardiac toxicity after anthracycline chemotherapy in childhood

The clinical use of anthracyclines, a family of chemotherapeutic agents with efficacy against many solid tumors and leukemias is limited by unique cumulative dose-limiting cardiotoxicity. Overt heart failure occurs in 4.5% to 7% of patients treated with anthracyclines and the incidence of cardiac function abnormalities increases with the time. Anthracycline-induced congestive heart failure is usually due to permanent changes in the myocardium, changes most consistent with the contractile failure of cardiomyopathy. Although the causes of anthracycline-induced cardiotoxicity are probably many, a large body of evidence points to free-radical-mediated myocyte damage. The risk of developing cardiac heart failure is modified by the presence of certain risk factors that reduce cardiac tolerance to anthracyclines. Age and female gender seem to have an important role in the anthracycline cardiotoxicity. This cardiotoxicity can be divided, on the base of when it started, into acute, subacute and progressive late, chronic form. Various invasive and non-invasive methods have been used to measure the extent of cardiac damage done. Depending on the sensitivity of the method employed, the proportion of hearts found to be damaged has varied widely. Attempts to ameliorate anthracycline cardiotoxicity have been directed toward: 1. decreasing myocardial concentrations of anthracyclines and their metabolites, 2. developing less cardiotoxic analogous, and 3. concurrently administering cardioprotectants to attenuate the effects of anthracyclines on the heart. Much progress has been made in terms of monitoring of clinical and subclinical anthracycline cardiotoxicity, finding alternative schedules, introducing special carriers of anthracyclines and using cardioprotecting agents. It is hoped that with all these effects and with results of ongoing and future trials, we will be able to reduce further or even eliminate anthracycline cardiotoxicity.     

Cardiac troponin I release in non-ischemic reversible myocardial injury from acute diphtheric myocarditis

Cardiac troponins are highly specific markers of myocardial injury. It has been suggested that, unlike other markers of myocardial injury, troponins could be released in reversible myocardial injury and the myocardial necrosis does not have to occur for troponins to be released from myocytes. Reversibly injury related changes in myocyte membrane are considered sufficient for the release of cardiac troponins from the free cytosolic pool, whereas in case of irreversible myocardial injury the source of troponin release is the structural damage of the myocytes. Diphtheria is a localized infection of skin and mucous membranes with multi-system involvement caused by gram-positive aerobic rod Corynebacterium diphtheriae. The cardiac involvement in diphtheria is characterized by severe impairment of cardiac contractility. The myocardial injury induced by diphtheric toxins could be completely reversible with successful treatment. We report a case of diphtheric myocarditis in a 20-year-old female who presented with complaints of dysphagia, dysphonia, fatigue, generalized malaise and severe dyspnea. She developed severe left ventricular systolic dysfunction (ejection fraction 10%) with markedly elevated serum levels of cardiac troponin I (peak 48.5 ng/ml). Within a few days on treatment, the cardiac function became completely normal (left ventricular ejection fraction 60%) and the elevation in serum level of cardiac troponin I resolved. This case supports the notion that cardiac troponin I could be released in reversible myocardial injury and that in such case the recovery of myocardial function is independent of serum levels of cardiac troponin I measured during the acute phase of illness.     

Tako-Tsubo-Kardiomyopathie – eine neue kardiale Entität?

In recent years, a new cardiac syndrome with transient left ventricular dysfunction has been widely reported in Japan. This new entity has been referred to as "tako-tsubo cardiomyopathy" or "apical ballooning", named for the particular shape of the end-systolic left ventricle in ventriculography. This syndrome has also been reported to occur in the western population. The clinical characteristics of this phenomenon have been described as follows: (1) acute onset of reversible left ventricular apical wall motion abnormalities (ballooning) with chest pain, (2) electrocardiographic changes (i.e., ST elevation), (3) minimal myocardial enzymatic release, and (4) no significant stenosis on coronary angiography. Severe emotional or physical stress usually precedes this cardiomyopathy. A unifying mechanistic explanation responsible for this acute but rapidly reversible contractile dysfunction is still lacking. Several investigations suggested catecholamine-mediated cardiotoxicity or coronary artery vasospasm, microvascular injury, an impaired fatty acid metabolism, or transient obstruction of the left ventricular outflow. The optimal treatment of patients presenting with this syndrome may depend on the stage of condition, since various pathophysiological mechanisms underlie the final clinical picture.     

Update on Incorporating Biomarkers with Imaging Findings for the Detection and Management of Cardiotoxicity

Purpose of Review

Modern cancer therapy comes at a cost of increased risk of cardiotoxicity. The purpose of our paper is to provide an updated review highlighting research incorporating biomarkers and imaging findings for the detection of subclinical cardiac dysfunction and management of cancer treatment-related cardiotoxicity.

Recent Findings

Biomarkers, particularly troponin, NTproBNP, and myeloperoxidase, have been shown to have a predictive role in the development of cancer treatment-related cardiotoxicity. Early reductions in global longitudinal strain and the more recently reported, circumferential strain, have been shown to be predictive of subsequent cardiotoxicity. Integrating troponin levels with longitudinal strain may have incremental value in predicting future cardiotoxicity. Initiating troponin-guided heart failure therapy following cancer treatment may impact the development of cardiotoxicity. Strain-guided heart failure therapy is currently under investigation.

Summary

Early detection of subclinical cardiac dysfunction in high-risk cancer patients and subsequent medical intervention using biomarkers and imaging may help to alter the course of cancer treatment-induced cardiotoxicity. Current guidelines and expert consensus offer a general framework for monitoring high risk patients for cardiotoxicity. However, additional research is needed to provide a more sophisticated and structured approach in detecting and managing subclinical cardiac dysfunction with hopes of minimizing subsequent cardiotoxicity.

     

Preventing the cardiotoxic effects of anthracyclins. From basic concepts to clinical data

The chronic cardiotoxicity of the cytotoxic agents such as anthracyclines is one of the main factors, which limits their prolonged use. Clinically, this cardiotoxicity results in a cardiomyopathy with irreversible congestive heart failure, with high mortality. The molecular mechanisms, which could explain this cardiac toxicity, are complex but it seems distinct from the anticancer mechanism. Several hypotheses were advanced but it appears that the induction of an oxidative stress within myocardial tissue constitutes the common denominator. The prevention of this cardiotoxicity lies on:--a rigorous cardiac monitoring--the use of anthracyclines analogues with lower cardiotoxicity,--modifications of the protocols of administration. The myocardial protection, with cardioprotective agents targeting oxidative stress during chemotherapy would be of great interest for an optimal use of the anthracyclines.     

Pharmacological Prevention of Peri-, and Post-Procedural Myocardial Injury in Percutaneous Coronary Intervention

In recent years, percutaneous coronary intervention (PCI) has become a well-established technique for the treatment of coronary artery disease. PCI improves symptoms in patients with coronary artery disease and it has been increasing safety of procedures. However, peri- and post-procedural myocardial injury, including angiographical slow coronary flow, microvascular embolization, and elevated levels of cardiac enzyme, such as creatine kinase and troponin-T and -I, has also been reported even in elective cases. Furthermore, myocardial reperfusion injury at the beginning of myocardial reperfusion, which causes tissue damage and cardiac dysfunction, may occur in cases of acute coronary syndrome. Because patients with myocardial injury is related to larger myocardial infarction and have a worse long-term prognosis than those without myocardial injury, it is important to prevent myocardial injury during and/or after PCI in patients with coronary artery disease. To date, many studies have demonstrated that adjunctive pharmacological treatment suppresses myocardial injury and increases coronary blood flow during PCI procedures. In this review, we highlight the usefulness of pharmacological treatment in combination with PCI in attenuating myocardial injury in patients with coronary artery disease.Key Words: Coronary artery disease, percutaneous coronary intervention, myocardial injury, pharmacology.     

Soluble Epoxide Hydrolase Inhibitors and Heart Failure

Cardiovascular disease remains one of the leading causes of death in the Western societies. Heart failure (HF) is due primarily to progressive myocardial dysfunction accompanied by myocardial remodeling. Once HF develops, the condition is, in most cases, irreversible and is associated with a very high mortality rate. Soluble epoxide hydrolase (sEH) is an enzyme that catalyzes the hydrolysis of epoxyeicosatrienoic acids (EETs), which are lipid mediators derived from arachidonic acid through the cytochrome P450 epoxygenase pathway. EETs have been shown to have vasodilatory, antiinflammatory, and cardioprotective effects. When EETs are hydrolyzed by sEH to corresponding dihydroxyeicosatrienoic acids, their cardioprotective activities become less pronounced. In line with the recent genetic study that has identified sEH as a susceptibility gene for HF, the sEH enzyme has received considerable attention as an attractive therapeutic target for cardiovascular diseases. Indeed, sEH inhibition has been demonstrated to have antihypertensive and antiinflammatory actions, presumably due to the increased bioavailability of endogenous EETs and other epoxylipids, and several potent sEH inhibitors have been developed and tested in animal models of cardiovascular disease including hypertension, cardiac hypertrophy, and ischemia/reperfusion injury. sEH inhibitor treatment has been shown to effectively prevent pressure overload‐ and angiotensin II‐induced cardiac hypertrophy and reverse the pre‐established cardiac hypertrophy caused by chronic pressure overload. Application of sEH inhibitors in several cardiac ischemia/reperfusion injury models reduced infarct size and prevented the progressive cardiac remodeling. Moreover, the use of sEH inhibitors prevented the development of electrical remodeling and ventricular arrhythmias associated with cardiac hypertrophy and ischemia/reperfusion injury. The data published to date support the notion that sEH inhibitors may represent a promising therapeutic approach for combating detrimental cardiac remodeling and HF.     

Chemotherapy-Induced Cardiotoxicity: Detection,Prevention, and Management

Chemotherapy-induced cardiotoxicity is a major cause of morbidity and mortality in cancer survivors. It might manifest as arrhythmia, hypertension, myocardial ischemia, thromboembolism, heart failure, systolic dysfunction, or other adverse events. Anthracyclines and trastuzumab are the chemotherapeutic agents with the most documented cardiac side effects; however, the array of novel molecular targeting therapies available is concerning because their side effects are not yet well understood. Nevertheless, there are potential strategies to mitigate the risks of cardiac complications for cancer patients. In this article, the common systemic drugs with cardiotoxic potential and the monitoring and diagnostic tools, including the role of biomarkers for early detection, are reviewed. We will also review the use of cardioprotectant agents as pharmacological interventions in prophylactic and treatment settings. Our aim is to provide a concise and up-to-date summary of the detection, management, and prevention of chemotherapy-induced cardiotoxicity for the busy clinician.     

Reversibility of severe left ventricular dysfunction due to doxorubicin cardiotoxicity. Report of three cases

Doxorubicin is a potent anticancer agent effective in a wide range of malignancies, but its use is limited by dose-dependent late cardiotoxicity. Severe doxorubicin cardiotoxicity has been associated with a poor prognosis and a high mortality rate, and until recently has been thought to be irreversible. We describe the cases of three patients with well-documented severe left ventricular dysfunction due to doxorubicin who had complete clinical recovery with return of cardiac function to normal. Because severe doxorubicin cardiotoxicity is reversible in some patients, aggressive supportive therapy is warranted.     

Biomarkers and Cancer Therapy-Related Cardiac Dysfunction

Cancer is a leading cause of morbidity and mortality, but improvements in therapy have translated to better outcomes. Despite this, patients exposed to certain cancer therapies may develop cardiac toxicity. Among cancer survivors, cardiovascular disease is currently the second leading cause of morbidity and mortality. The spectrum of cardiac disease is broad, including asymptomatic left ventricular dysfunction through cardiac failure, among other cardiovascular events. Novel imaging techniques such as speckle tracking/strain and three-dimensional echocardiogram are useful for evaluating cancer therapy-induced cardiotoxicity, but they are limited in clinical practice by local expertise and lack of widespread availability. There is no universally accepted imaging method or protocol for the identification of subclinical cardiotoxicity. The last several years have seen a growing exploration of serum cardiac biomarkers such as troponins, natruretic peptides, C-reactive protein, and others for the screening and monitoring of cancer therapy-associated cardiac dysfunction. This review examines recent literature surrounding the use of cardiac biomarkers for surveillance, diagnosis, and management of cardiac dysfunction related to cancer therapy, highlighting the limited data to support recommendations.     

Cardiomyopathy Associated With Cancer Therapy

Chemotherapy-associated cardiomyopathy is a well known cardiotoxicity of contemporary cancer treatment and a cause of increasing concern for both cardiologists and oncologists. As cancer outcomes improve, cardiovascular disease has become a leading cause of morbidity and mortality among cancer survivors. Asymptomatic or symptomatic left ventricular systolic dysfunction in the setting of cardiotoxic chemotherapy is an important entity to recognize. Early diagnosis of cardiac injury through the use of novel blood-based biomarkers or noninvasive imaging modalities may allow for the initiation of cardioprotective medications or modification of chemotherapy regimen to minimize or prevent further damage. Several clinical trials are currently underway to determine the efficacy of cardioprotective medications for the prevention of chemotherapy-associated cardiomyopathy. Implementing a strategy that includes both early detection and prevention of cardiotoxicity will likely have a significant impact on the overall prognosis of cancer survivors. Continued coordination of care between cardiologists and oncologists remains critical to maximizing the oncologic benefit of cancer therapy while minimizing any early or late cardiovascular effects.