Use of myocardial deformation imaging to detect preclinical myocardial dysfunction before conventional measures in patients undergoing breast cancer treatment with trastuzumab

Cardiac testing to manage cardiovascular risk in cancer patients

Cardiovascular toxicity is one of the most feared complications of cancer treatment. Recent advances in oncologic therapies have resulted in improved cancer outcomes but also a new set of cardiovascular adverse effects. Common toxicities include left ventricular dysfunction/heart failure, hypertension, and myocardial ischemia. Accurate risk stratification allows avoidance of potentially harmful treatments in those patients at greatest risk while maintaining the ability to deliver high doses of effective therapies to the lower-risk population. Cardiac investigations, including echocardiography, nuclear imaging, magnetic resonance imaging, biomarker measurement, blood pressure monitoring, electrocardiography, stress testing, and invasive angiography, can help to risk-stratify selected patients. In this review, common complications are discussed in terms of the factors used to identify patients with elevated risk, the monitoring strategies available, and selected interventions that have been used to modify outcomes in patients identified as being at high risk for cardiac complications of cancer treatment.

Cardioprotective Effect of β-Adrenoceptor Blockade in Patients With Breast Cancer Undergoing Chemotherapy

Background—

Chemotherapy with trastuzumab and anthracycline is associated with incident heart failure (HF) in patients with breast cancer. We hypothesized that continuous incidental use of β-blocker agents (BB) was protective against HF in patients without established structural heart disease who were receiving trastuzumab and anthracycline.

Methods and Results—

We identified 920 consecutive patients with breast cancer (age 52.3±11.0 years) with normal ejection fraction before receiving trastuzumab and anthracycline therapy at our institution between 2005 and 2010. Using a propensity score and a greedy 5 to 1 digit-matching algorithm, 106 of these patients on continuous BB during cancer treatment were matched with 212 patients from the same pool with similar characteristics but not on continuous BB. During a median follow-up of 3.2±2.0 years, 32 incident HF admissions were identified in these 318 patients with breast cancer, whereas 28 cancer-related (noncardiac) deaths occurred before any incident HF. Cumulative incidence regression models and cause-specific hazards of new HF events were estimated from competing risk Cox models of time-dependent covariates. Although trastuzumab therapy showed significant association with incident HF, independent of anthracycline-related cardiotoxicity (hazard ratio, 9.0; 95% confidence interval, 3.0–27.0; P <0.0001), continuous use of BB was associated with lower risk of new HF events (hazard ratio, 0.2; 95% confidence interval, 0.1–0.5; P =0.003).

Conclusions—

Coincidental, continuous use of BB is associated with lower incidence of HF in patients with breast cancer and normal baseline ejection fraction in a competing risk framework, and after matching for demographics, clinical, and cancer-related treatment characteristics. Prospective randomized clinical trials to validate these findings are warranted.

What is the primary source of discordance in strain measurement between vendors: imaging or analysis?

Strain imaging quantifies myocardial deformation in both overt and subclinical myocardial diseases. Strain values have been shown to vary between vendors. The aim of this study was to investigate whether this variation reflects differences of image characteristics or analysis software. We enrolled 45 patients (age 54 ± 14 years, 26 males) who underwent two echocardiograms on the same day with two different commercially available ultrasound systems. Three apical views were analyzed by two vendor-specific and two digital imaging and communications in medicine (DICOM)-based software packages. The results were compared in two ways; comparison of global longitudinal strain (GLS) by nine different combinations of ultrasound systems and strain software, and comparison of strains by wall, view and global levels. Comparison of GLS between two vendor-specific software packages yielded poor correlation (ρ = 0.35). The use of the same software on the images from different vendors was concordant (ρ = 0.74 and 0.64; bias = 0.0 and -0.5). There were no significant differences in correlation coefficients among the comparisons with DICOM-based software. There was no significant difference in correlation coefficients among three views (4CV vs. 3CV, p = 0.44; 4CV vs. 2CV, p = 0.47). Comparison of walls showed the septum to have the best correlation (ρ = 0.73), and the posterior wall (ρ = 0.31; p = 0.005 vs. septum) had the worst. Use of the same software to measure strain in images from different vendors minimizes the variation of GLS. Post-processing is the most important determinant in inter-vendor variation, with differences in acquisition having a small effect. These findings should be examined and confirmed with other combinations of ultrasound machines and deformation software.

Reproducibility of echocardiographic techniques for sequential assessment of left ventricular ejection fraction and volumes: application to patients undergoing cancer chemotherapy

OBJECTIVES

The aim of this study was to identify the best echocardiographic method for sequential quantification of left ventricular (LV) ejection fraction (EF) and volumes in patients undergoing cancer chemotherapy.

BACKGROUND

Decisions regarding cancer therapy are based on temporal changes of EF. However the method for EF measurement with the lowest temporal variability is unknown.

METHODS

We selected patients in whom stable function in the face of chemotherapy for breast cancer was defined by stability of global longitudinal strain (GLS) at up to 5 time points (baseline, 3, 6, 9, and 12 months). In this way, changes in EF were considered to reflect temporal variability of measurements rather than cardiotoxicity. A comprehensive echocardiogram consisting of 2-dimensional (2D) and 3-dimensional (3D) acquisitions with and without contrast administration was performed at each time point. Stable LV function was defined as normal GLS (≤-16.0%) at each examination. The EF and volumes were measured with 2D-biplane Simpson's method, 2D-triplane, and 3-dimensional echocardiography (3DE) by 2 investigators blinded to any clinical data. Inter-, intra-, and test-retest variability were assessed in a subgroup. Variability was assessed by analysis of variance and compared with Levene's or t test.

RESULTS

Among 56 patients (all female, 54 ± 13 years of age), noncontrast 3D EF, end-diastolic volume, and end-systolic volume had significantly lower temporal variability than all other methods. Contrast only decreased the temporal variability of LV end-diastolic volume measurements by the 2D biplane method. Our data suggest that a temporal variability in EF of 0.06 might occur with noncontrast 3DE due to physiological differences and measurement variability, whereas this might be >0.10 with 2D methods. Overall, 3DE also had the best intra- and inter-observer as well as test-retest variability.

CONCLUSIONS

Noncontrast 3DE was the most reproducible technique for LVEF and LV volume measurements over 1 year of follow-up.

Subclinical cardiotoxicity detected by strain rate imaging up to 14 months after breast radiation therapy

PURPOSE

Strain rate imaging (SRI) is a new echocardiographic modality that enables accurate measurement of regional myocardial function. We investigated the role of SRI and troponin I (TnI) in the detection of subclinical radiation therapy (RT)-induced cardiotoxicity in breast cancer patients.

METHODS AND MATERIALS

This study prospectively included 75 women (51 left-sided and 24 right-sided) receiving adjuvant RT to the breast/chest wall and regional lymph nodes. Sequential echocardiographs with SRI were obtained before RT, immediately after RT, and 8 and 14 months after RT. TnI levels were measured on the first and last day of RT.

RESULTS

Mean heart and left ventricle (LV) doses were both 9 ± 4 Gy for the left-sided patients and 4 ± 4 Gy and 1 ± 0.4 Gy, respectively, for the right-sided patients. A decrease in strain was observed at all post-RT time points for left-sided patients (-17.5% ± 1.9% immediately after RT, -16.6% ± 1.4% at 8 months, and -17.7% ± 1.9% at 14 months vs -19.4% ± 2.4% before RT, P<.01) but not for right-sided patients. When we considered left-sided patients only, the highest mean dose was given to the anterior left ventricular (LV) wall (25 ± 14 Gy) and the lowest to the inferior LV wall (3 ± 3 Gy). Strain of the anterior wall was reduced after RT (-16.6% ± 2.3% immediately after RT, -16% ± 2.6% at 8 months, and -16.8% ± 3% at 14 months vs -19% ± 3.5% before RT, P<.05), whereas strain of the inferior wall showed no significant change. No changes were observed with conventional echocardiography. Furthermore, mean TnI levels for the left-sided patients were significantly elevated after RT compared with before RT, whereas TnI levels of the right-sided patients remained unaffected.

CONCLUSIONS

In contrast to conventional echocardiography, SRI detected a regional, subclinical decline in cardiac function up to 14 months after breast RT. It remains to be determined whether these changes are related to clinical outcome. In the meantime, we encourage the use of radiation techniques that minimize the exposure of the anterior LV wall in left-sided patients.

Detection and prevention of cardiac complications of cancer chemotherapy

Despite continuous improvements in management of patients with cancer, cardiac side-effects still account for a substantial limitation of chemotherapy. Evaluation of cardiac toxicity in patients includes consideration of biomarkers such as cardiac troponins and B-type natriuretic peptides, together with non-invasive imaging in the form of 2D-, 3D-, or strain-echocardiography, multiple gated radionuclide angiography, quantitative gated blood-pool SPECT, (123)I-metaiodobenzylguanidine scintigraphy, or cardiac magnetic resonance imaging. These approaches differ from each other with regards to availability, accuracy, sensitivity to detect early stages of cardiac injury, individual reliability, ease of use in a longitudinal follow-up perspective, and to related cost-effectiveness. Improving prevention of these cardiac side-effects depends on several, currently unresolved issues. Early detection and quantification of cardiac damage is required to adapt chemotherapy in progress for optimal management of patients. Whether increased availability of myocardial strain imaging and repeat blood biomarkers determinations will reliably and consistently achieve these goals remain to be confirmed. Also, protective approaches to reduce cardiac toxicity of anticancer drugs should be reconsidered according to the recently restricted approval for use of dexrazoxane. Anthracycline-based regimens, encapsulated anthracyclines and non-anthracycline regimens should be revisited with regards to antitumour efficacy and cardiac toxicity. Cardiovascular drugs that proved effective in prevention of anthracycline-induced cardiac toxicity in experimental models should be investigated in clinical trials. Finally, the efficacy of cardiovascular drugs that have already been tested in clinical settings should be confirmed and compared with each other in patients in increased numbers.

Use of echocardiography to evaluate the cardiac effects of therapies used in cancer treatment: what do we know?

Cardiologists and oncologists today face the daunting challenge of identifying patients at risk for late-onset left ventricular (LV) systolic dysfunction from the use of various chemotherapeutic agents. Currently, the most widely used method in clinical practice for monitoring the potential of chemotherapy-induced cardiotoxicity is calculation of LV ejection fraction. The use of LV ejection fraction to determine whether to continue or discontinue the use of chemotherapeutic agents is limited, because decreases in LV ejection fraction frequently occur late and can be irreversible. These limitations have led to the exploration of diastolic function and newer modalities that assess myocardial mechanics to identify sensitive and specific variables that can predict the occurrence of late systolic function. The cancer therapies associated with cardiotoxicity are reviewed in this report. Additionally, the authors evaluate the role of present-day echocardiographic parameters, complementary noninvasive imaging modalities, and biomarkers in the prediction of cardiotoxicity. The authors address the evolving role of cardioprotective agents and potential therapies to prevent or reverse the progression of LV systolic dysfunction. Finally, they provide some ideas regarding future directions to enhance the knowledge of predicting late-onset LV systolic dysfunction secondary to cancer therapy.

The role of 3D wall motion tracking in heart failure

Heart failure is a major health problem in developed countries and a growing one in developing countries. Cardiac remodeling in heart failure affects myocardial mechanics, which requires comprehensive evaluation in three dimensions. The novel technique of 3D wall motion tracking applies speckle tracking technology to full volume, 3D echocardiographic datasets. Quantification of conventional and novel left ventricular (LV) parameters including volumes, ejection fraction, global and regional 3D strain, endocardial area strain, twist, and dyssynchrony, and identification of the site of latest mechanical activation are feasible on the basis of a single acquisition of a full-volume dataset. Clinical applications of 3D wall motion tracking include the assessment of global and regional LV performance in ischemic and nonischemic heart diseases, evaluation of mechanics in cardiomyopathies and congenital heart disease, potential selection of patients for cardiac resynchronization therapy and prediction of their response, and detection of subclinical cardiac dysfunction in diseases with likelihood of progression to heart failure. Technological advances with improvement in spatial and temporal resolution of this novel imaging modality are expected. Although 3D wall motion tracking is still in its infancy, this method has begun to provide new insights into LV mechanics and has already found clinical applications. Future developments in 3D assessment of right ventricular and myocardial layer-specific mechanics are awaited.

Breast cancer therapies and cardiomyopathy

The prevalence of chemotherapy-related cardiac disease is increasing and management demands a multidisciplinary approach from cardiologists and oncologists. Pretreatment identification of predisposing risk factors and assessment of cardiac function before and at intervals during and after therapy with cardiotoxic agents are necessary. In clinical practice, surveillance is largely performed using transthoracic echocardiography or multi-gated radionuclide angiography. Imaging strategies that detect cardiac injury before overt left ventricular systolic dysfunction provide an opportunity for early intervention and improved cardiac outcomes.

Early detection of chemotherapy-related left ventricular dysfunction

Modern advances in cancer treatment have resulted in improved survival. As a result, effects of cancer therapy on other organ systems such as the heart are more likely to become clinically relevant. One such possibility is chemotherapy-related left ventricular dysfunction. Although in clinical practice cardiotoxicity is evaluated by symptoms and left ventricular ejection fraction, these occur relatively late in the disease process after the heart's compensatory mechanisms have been expended. Ideally, left ventricular dysfunction would be identified early so that cancer patients and their physicians can make informed decisions about their therapeutic options and institute careful surveillance and early initiation of cardioprotective medication where appropriate. This review discusses the role of echocardiography to detect subclinical left ventricular dysfunction in cancer patients exposed to chemotherapy with potential cardiotoxicity, particularly anthracyclines and trastuzumab.

Assessing the Cardiac Toxicity of Chemotherapeutic Agents: Role of Echocardiography

Advancements in cancer treatment have resulted in sufficient survival length for patients to experience treatment-related cardiac complications. In particular, chemotherapy-induced cardiac dysfunction significantly impacts morbidity and mortality rates in cancer patients. The presence of cardiotoxicity from chemotherapy has been traditionally assessed using clinical symptoms and decreases in left ventricular ejection fraction (LVEF). However, in this indication, LVEF lacks accuracy as a measure of subclinical cardiotoxicity and its prognostic value is controversial. There is an emphasis to identify subclinical and left ventricular dysfunction early, in order to allow cancer patients and their physicians to make informed decisions about therapeutic options. Echocardiography is a readily available noninvasive tool to measure cardiac function and plays a major role in the diagnosis of cardiotoxicity. This review focuses on the role of echocardiography in detecting cardiotoxicity, and will discuss conventional and more recent echocardiographic approaches for assessing subclinical cardiotoxicity.

Assessment of echocardiography and biomarkers for the extended prediction of cardiotoxicity in patients treated with anthracyclines, taxanes, and trastuzumab

BACKGROUND

Because cancer patients survive longer, the impact of cardiotoxicity associated with the use of cancer treatments escalates. The present study investigates whether early alterations of myocardial strain and blood biomarkers predict incident cardiotoxicity in patients with breast cancer during treatment with anthracyclines, taxanes, and trastuzumab.

METHODS AND RESULTS

Eighty-one women with newly diagnosed human epidermal growth factor receptor 2-positive breast cancer, treated with anthracyclines followed by taxanes and trastuzumab were enrolled to be evaluated every 3 months during their cancer therapy (total of 15 months) using echocardiograms and blood samples. Left ventricular ejection fraction, peak systolic longitudinal, radial, and circumferential myocardial strain were calculated. Ultrasensitive troponin I, N-terminal pro-B-type natriuretic peptide, and the interleukin family member (ST2) were also measured. Left ventricular ejection fraction decreased (64 ± 5% to 59 ± 6%; P<0.0001) over 15 months. Twenty-six patients (32%, [22%-43%]) developed cardiotoxicity as defined by the Cardiac Review and Evaluation Committee Reviewing Trastuzumab; of these patients, 5 (6%, [2%-14%]) had symptoms of heart failure. Peak systolic longitudinal myocardial strain and ultrasensitive troponin I measured at the completion of anthracyclines treatment predicted the subsequent development of cardiotoxicity; no significant associations were observed for left ventricular ejection fraction, N-terminal pro-B-type natriuretic peptide, and ST2. Longitudinal strain was <19% in all patients who later developed heart failure.

CONCLUSIONS

In patients with breast cancer treated with anthracyclines, taxanes, and trastuzumab, systolic longitudinal myocardial strain and ultrasensitive troponin I measured at the completion of anthracyclines therapy are useful in the prediction of subsequent cardiotoxicity and may help guide treatment to avoid cardiac side-effects.

Non-invasive imaging and monitoring cardiotoxicity of cancer therapeutic drugs

Cardiotoxicity due to administration of cancer therapeutic agents such as anthracyclines and herceptin are well described. Established guidelines to screen for chemotherapy-related cardiotoxicity (CRC) are primarily based on serial assessment of left ventricular (LV) ejection fraction (EF). However, other parameters such as LV volume, diastolic function, and strain may also be useful in screening for cardiotoxicity. More recent advances in molecular imaging of apoptosis and tissue characterization by cardiac MRI are techniques which might allow early detection of patients at high risk for developing cardiotoxicity prior to a drop in EF. This comprehensive multi-modality review will discuss both the current established imaging techniques as well as the emerging technologies which may revolutionize the future of screening and evaluation for CRC.

Role of echocardiography in cancer care

For cancer therapy survivors, regular echocardiographic follow-up of left ventricular function is considered part of standard care. Metastases of tumors on the pericardium and myocardium as well as cardiac structure and function can be assessed using echocardiography. This review focuses on current and developing echocardiographic modalities for the assessment of cardiac structure and function in the cancer patient, delineates the echocardiographic diagnosis of cardiac amyloidosis, and discusses the echocardiographic features of cardiac masses including those associated with the hypercoagulable state of cancer.

Detection, monitoring, and management of trastuzumab-induced left ventricular dysfunction: an actual challenge

The antibody trastuzumab, targeted to inhibit the signalling of ErbB2, a tyrosine kinase receptor overexpressed in 20-30% of breast cancers, improves the prognosis in women affected by this tumour, but produces cardiotoxicity, since ErbB2 is also involved in myocardial homeostasis. In this review, we discuss the pathophysiology of trastuzumab cardiomyopathy and the complex interplay between ErbB2 inhibition and anthracyclines, and we focus on the actual challenges of detecting, monitoring, and managing trastuzumab cardiotoxicity: the research of new, sensitive markers of early trastuzumab toxicity, before the ejection fraction is reduced, is an active field of research.

Newest echocardiographic techniques for the detection of cardiotoxicity and heart failure during chemotherapy

Chemotherapy-induced cardiotoxicity has become a significant public health issue. Left ventricular ejection fraction is routinely used to monitor cardiotoxicity but fails to detect subtle alterations in cardiac function. Improvements in the measurement of left ventricular ejection fraction, physical or pharmacologic stressors, and novel cardiac functional indices may be useful in the detection of cardiotoxicity. The improvements in the detection and therapy of cancer have led to the emergence of chemotherapy-induced cardiotoxicity. New echocardiographic techniques may be useful in the detection of patients undergoing chemotherapy treatments who could benefit from alternative cancer treatments, therefore decreasing the incidence of cardiotoxicity.

Baseline diastolic dysfunction as a predictive factor of trastuzumab-mediated cardiotoxicity after adjuvant anthracycline therapy in breast cancer

To evaluate the interest in assessing left ventricular diastolic function at baseline for prediction of trastuzumab-mediated cardiotoxicity (TMC) in the setting of adjuvant treatment for breast cancer. The study included 118 women presenting with HER2-positive early-stage invasive breast cancer. Patients received trastuzumab therapy over 1 year, concurrent with six cycles of docetaxel (n = 53), or following anthracycline-based chemotherapy with a cumulative dose of 300 mg/m(2) (n = 45) or 600 mg/m(2) (n = 20) of epirubicine. RNA was performed before anthracycline-based chemotherapy, before trastuzumab treatment (baseline), and every 3 months during treatment. Left ventricular ejection fraction (LVEF) and peak ejection rate (PER) were calculated to evaluate LV systolic function; peak filling rate (PFR), and time to peak filling rate (TPFR) were also calculated to evaluate LV diastolic function. Eighteen patients (15%) developed grade 1 or 2 TMC during follow-up. No significant difference was observed for age, cardiovascular risk factors, fasting blood glucose level, heart rate, systolic blood pressure, baseline LVEF, PER, and PFR between patients with and without TMC. In contrast, patients with TMC showed a longer TPFR at baseline (median [Q1-Q3]: 165 ms [149-190] vs. 142 ms [130-162]; P < 0.001). Furthermore, by logistic regression analysis, baseline TPFR >180 ms and the cumulative dose of epirubicin remained independent predictors of TMC. Patients receiving 600 mg/m(2) of epirubicin before trastuzumab showed a higher incidence of TMC (35%) than did both patients who previously received 300 mg/m(2) of epirubicin (13%) and those who received only docetaxel associated with trastuzumab (9%). Impaired left ventricular diastolic function before treatment is an independent predictor of trastuzumab-mediated cardiotoxicity. The evaluation of diastolic function could allow optimal risk stratification before the introduction of trastuzumab.

The utility of cardiac biomarkers, tissue velocity and strain imaging, and cardiac magnetic resonance imaging in predicting early left ventricular dysfunction in patients with human epidermal growth factor receptor II-positive breast cancer treated with adjuvant trastuzumab therapy

OBJECTIVES

The aim of this study was to evaluate whether cardiac biomarkers, tissue velocity (TVI) and strain imaging, and cardiac magnetic resonance imaging can predict early left ventricular (LV) dysfunction in human epidermal growth factor receptor II-positive breast cancer patients treated with trastuzumab in the adjuvant setting.

BACKGROUND

Early indexes of LV systolic dysfunction with noninvasive cardiac imaging would be useful for addressing the cardiac safety profile of trastuzumab, potentially avoiding the detrimental effects of heart failure.

METHODS

We used cardiac biomarkers, TVI and strain imaging, and cardiac magnetic resonance imaging to detect pre-clinical changes in LV systolic function, before conventional changes in left ventricular ejection fraction (LVEF) in human epidermal growth factor receptor II-positive breast cancer patients treated with trastuzumab in the adjuvant setting.

RESULTS

Of 42 patients (mean age 47 ± 9 years) prospectively followed between 2007 and 2009, 10 (25%) developed trastuzumab-mediated cardiomyopathy (CM). Troponin T, C-reactive protein, and brain natriuretic peptide did not change over time. Within 3 months of adjuvant therapy with trastuzumab, there was a significant difference in the lateral S' between the normal cohort and the CM group (9.1 ± 1.6 cm/s and 6.4 ± 0.6 cm/s, respectively, p < 0.05). Similarly, the peak global longitudinal and radial strain decreased as early as 3 months in the trastuzumab-mediated cardiotoxicity group. As compared with both global longitudinal and radial strain, only S' was able to identify all 10 patients who developed trastuzumab-mediated CM. The LVEF subsequently decreased at 6 months of follow-up in all 10 patients, necessitating discontinuation of the drug. All 10 patients demonstrated delayed enhancement of the lateral wall of the LV within the mid-myocardial portion, consistent with trastuzumab-induced CM.

CONCLUSIONS

Both TVI and strain imaging were able to detect pre-clinical changes in LV systolic function, before conventional changes in LVEF, in patients receiving trastuzumab in the adjuvant setting.

Early detection and prediction of cardiotoxicity in chemotherapy-treated patients

As breast cancer survival increases, cardiotoxicity associated with chemotherapeutic regimens such as anthracyclines and trastuzumab becomes a more significant issue. Assessment of the left ventricular (LV) ejection fraction fails to detect subtle alterations in LV function. The objective of this study was to evaluate whether more sensitive echocardiographic measurements and biomarkers could predict future cardiac dysfunction in chemotherapy-treated patients. Forty-three patients diagnosed with breast cancer who received anthracyclines and trastuzumab therapy underwent echocardiography and blood sampling at 3 time points (baseline and 3 and 6 months during the course of chemotherapy). The LV ejection fraction; peak systolic myocardial longitudinal, radial, and circumferential strain; echocardiographic markers of diastolic function; N-terminal pro-B-type natriuretic peptide; and high-sensitivity cardiac troponin I were measured. Nine patients (21%) developed cardiotoxicity (1 at 3 months and 8 at 6 months) as defined by the Cardiac Review and Evaluation Committee reviewing trastuzumab. A decrease in longitudinal strain from baseline to 3 months and detectable high-sensitivity cardiac troponin I at 3 months were independent predictors of the development of cardiotoxicity at 6 months. The LV ejection fraction, parameters of diastolic function, and N-terminal pro-B-type natriuretic peptide did not predict cardiotoxicity. In conclusion, cardiac troponin plasma concentrations and longitudinal strain predict the development of cardiotoxicity in patients treated with anthracyclines and trastuzumab. The 2 parameters may be useful to detect chemotherapy-treated patients who may benefit from alternative therapies, potentially decreasing the incidence of cardiotoxicity and its associated morbidity and mortality.

Multimodality imaging in the evaluation of cardiovascular manifestations of malignancy

Up to one third of the population will die as a direct result of cancer. Accurate and timely diagnosis of disease often requires multiple different approaches including the use of modern imaging techniques. Prompt recognition of adverse consequences of some anti-cancer therapies also requires a knowledge of the optimum imaging strategy for the problem at hand. The purpose of this article is to review not only some of the commoner cardiovascular manifestations of malignancy but also to discuss the strengths, weaknesses and appropriate use of cardiovascular imaging modalities.

Cardiovascular Disease

Although important advances have been made in curing childhood cancer in the last several decades, long-term survivors face considerable morbidity and mortality because of late effects from their initial anticancer therapy. By 30 years after treatment, the cumulative mortality from treatment-related medical illness actually exceeds that of mortality from cancer recurrence. Cardiovascular disease, in particular, is a leading threat to the well-being of adult survivors of childhood cancers. Unfortunately, the mechanisms of these late cardiac effects are understudied and poorly understood. This article reviews cardiotoxicity associated with 2 major anticancer regimens used in treating childhood cancer patients: anthracycline treatment and radiation therapy. The known pathophysiology and clinical cardiac risk factors that further predispose these patients to late-onset cardiac events are discussed. Basic and translational research is urgently needed to clarify pathophysiologic mechanisms of late cardiac effects and to develop therapies to improve both long-term survival and quality of life of adults cured of pediatric cancers.

Left ventricular function assessed by two-dimensional speckle tracking echocardiography in long-term survivors of Hodgkin's lymphoma treated by mediastinal radiotherapy with or without anthracycline therapy

Anthracycline therapy is well known for its adverse cardiac effects. However, few studies have been performed of the long-term follow-up of myocardial function in adult survivors of Hodgkin's lymphoma receiving anthracycline. Two-dimensional speckle tracking echocardiography is an accurate angle-independent modality for the quantification of left ventricular (LV) function. The aim of the present study was to investigate the long-term effect of anthracycline on LV systolic function. Echocardiography was performed in 47 survivors of Hodgkin's lymphoma 22 ± 2 years after successful mediastinal radiotherapy with (n = 27) or without (n = 20) anthracycline (doxorubicin) treatment and in 20 healthy controls. LV function was assessed by the LV ejection fraction and global longitudinal and circumferential strain. Both patient groups had received a similar dosage of radiation, and doxorubicin was given at a total dose of 309 ± 92 mg. The global longitudinal strain was reduced in patients receiving anthracycline with mediastinal radiotherapy compared to the other group receiving mediastinal radiotherapy alone or combined radiotherapy and regimens without anthracyclines (-16.1 ± 1.9% vs -17.5 ± 1.7%, respectively, p <0.05). Both patient groups had reduced strain compared to the healthy controls (-20.4 ± 1.7%, both p <0.001). The circumferential strain was also reduced in the treatment groups (-18.3 ± 3.2% and -17.8 ± 3.6% vs -22.5 ± 2.1%, both p <0.001). The LV ejection fraction did not differ between the patient groups (55 ± 8% vs 56 ± 6%, p = 1.0) but was reduced compared to that of the controls (62 ± 5%, both p <0.05). In conclusion, myocardial function was reduced in the survivors of Hodgkin's lymphoma 2 decades after successful treatment consisting of mediastinal radiotherapy with or without chemotherapy. Patients receiving anthracycline therapy had additional negative long-tem effects on LV systolic function.

Speckle-tracking echocardiography: a new technique for assessing myocardial function

Speckle-tracking echocardiography has recently emerged as a quantitative ultrasound technique for accurately evaluating myocardial function by analyzing the motion of speckles identified on routine 2-dimensional sonograms. It provides non-Doppler, angle-independent, and objective quantification of myocardial deformation and left ventricular systolic and diastolic dynamics. By tracking the displacement of the speckles during the cardiac cycle, strain and the strain rate can be rapidly measured offline after adequate image acquisition. Data regarding the feasibility, accuracy, and clinical applications of speckle-tracking echocardiography are rapidly accumulating. This review describes the fundamental concepts of speckle-tracking echocardiography, illustrates how to obtain strain measurements using this technique, and discusses their recognized and developing clinical applications.

The potential role of echocardiographic strain imaging for evaluating cardiotoxicity due to cancer therapy

Refinements to conventional treatment and the development of new therapies have led to significant improvements in cancer survival. Yet, many frontline cancer treatments continue to be hindered by their significant side effects, amongst which cardiotoxicity is particularly important. Therefore, the focus of cancer management has changed; treatment is no longer aimed solely at overcoming malignancy, but emphasises early identification and treatment of potential side effects. In this regard, the cardiotoxic potential of certain anticancer agents mandate close monitoring of cardiac function, and the method of choice for monitoring is transthoracic echocardiography. Whilst this method has its limitations, a newer echocardiographic technique called myocardial strain imaging has the potential to detect early sub-clinical changes in cardiac function due to cardiotoxicity. Strain analysis has been the subject of several recent studies to evaluate its potential in monitoring cardiotoxicity, and this article reviews the recent literature and explores the potential role of myocardial strain imaging in cancer management and avenues for future research.

Assessment of myocardial mechanics using speckle tracking echocardiography: fundamentals and clinical applications

The authors summarize the recent developments in speckle-tracking echocardiography (STE), a relatively new technique that can be used in conjunction with two-dimensional or three-dimensional echocardiography for resolving the multidirectional components of left ventricular (LV) deformation. The tracking system is based on grayscale B-mode images and is obtained by automatic measurement of the distance between 2 pixels of an LV segment during the cardiac cycle, independent of the angle of insonation. The integration of STE with real-time cardiac ultrasound imaging overcomes some of the limitations of previous work in the field and has the potential to provide a unified framework to more accurately quantify the regional and global function of the left ventricle. STE holds promise to reduce interobserver and intraobserver variability in assessing regional LV function and to improve patient care while reducing health care costs through the early identification of subclinical disease. Following a brief overview of the approach, the authors pool the initial observations from clinical studies on the development, validation, merits, and limitations of STE.