Cardiac toxicity of high-dose chemotherapy.

Cardiac toxicity is an uncommon but potentially serious complication of high-dose (HD) chemotherapy and little is known about incidence, severity and underlying mechanisms. We have systematically reviewed the literature of the last 30 years to summarize and appraise the published evidence on cardiac toxicity associated with HD chemotherapy. HD cyclophosphamide-containing regimens have been most commonly associated with cardiac toxicity, with a progressively decreasing incidence over time. Dosage, application regimens and coadministration of other chemotherapeutic agents emerged as risk factors. While cardiac toxicity has been rarely associated with other cytotoxic drugs, an unexpected incidence of severe cardiotoxicity resulted from reduced-intensity conditioning regimens containing melphalan and fludarabine. Predictive value of cardiologic examination of patients is limited, and patients with a slight depression of cardiac performance could tolerate HD chemotherapy. Clinical examination, resting electrocardiography and dosage adjustment in overweight patients remain the mainstay of prevention, with bidimensional echocardiography (2D echo) for patients with a history of anthracycline exposure. Strategies to decrease the long-term negative impact of anthracycline administration on cardiac performance are being investigated. New 2D echo-based techniques and circulating markers of cardiac function hold promise for allowing identification of patients at high risk for and early diagnosis of cardiac toxicity.

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.

[Assessment of cardiotoxicity of high dose cyclophosphamide with electrocardiographic, echocardiographic, and troponin I monitoring in patients with breast tumors]. / Analisi della cardiotossicità da ciclofosfamide ad alte dosi mediante monitoraggio elettrocardiografico, ecocardiografico e della troponina I in pazienti con tumore della mammella.

BACKGROUND: High-dose cyclophosphamide is the nucleus for virtually all high-dose chemotherapy protocols. Non-hematologic dose-limiting toxicity is represented by acute cardiomyopathy, even fatal in a minority of patients. The pathophysiology of such a cardiotoxicity is still poorly understood. Postmortem studies revealed hemorrhagic myocardial cell death, endothelial damage, and interstitial edema. Recently troponins, in particular troponin I, have been found to represent uniquely sensitive and specific markers of myocyte membrane integrity, thus to increase in response to myocardial cell damage in different clinical settings. METHODS: We performed a multiparametric monitoring in 16 consecutive breast cancer patients undergoing cyclophosphamide, by means of serial ECGs, cardiac enzymes determinations (creatine phosphokinase, MB mass and troponin I) through 0 to 72 hours, and echocardiography at baseline and after 48 hours. RESULTS: Neither overt cardiac failure nor enzyme elevation were recorded. Serial ECGs revealed a reduction in QRS voltage and/or ST segment abnormalities in 6 cases. Echocardiography showed an increase in left ventricular diastolic and/or systolic diameters and volumes in 4 cases but without any decrease in fractional shortening and ejection fraction under normal values: in 2 of them abnormalities of diastolic function (E/A mitral Doppler ratio, isovolumic relaxation time and deceleration time) were also recorded. CONCLUSIONS: Our protocol of cyclophosphamide administration did not cause cardiac toxicity by myocardial cell damage, as analyzed by troponin I levels, thus suggesting that myocyte membrane injury is not the first mechanism of it. ECG (i.e. QRS voltages) and echo-Doppler (i.e. E/A ratio) monitoring lead to hypothesize that endothelial injury and interstitial edema with subsequent reduction in left ventricular diastolic compliance may be the first signs of cardiac dysfunction in this clinical setting.