Anthracyclines and Biomarkers of Myocardial Injury: The Effect of Remote Ischemic Conditioning.

Background: Remote ischemic conditioning (RIC) has been beneficial in laboratory studies of anthracycline cardiotoxicity, but its effects in patients is not established. Objectives: The authors studied the effect of RIC on cardiac biomarkers and function during and after anthracycline chemotherapy. Methods: The ERIC-Onc study (Effect of Remote Ischaemic Conditioning in Oncology Patients; NCT02471885) was a randomized, single-blind, sham-controlled study of RIC at each chemotherapy cycle. The primary endpoint was troponin T (TnT) during chemotherapy and up to 1 year. Secondary outcomes included cardiac function, major adverse cardiovascular events (MACE), and MACE or cancer death. Cardiac myosin-binding-protein C (cMyC) was investigated in parallel with TnT. Results: The study was prematurely halted after the evaluation of 55 patients (RIC n = 28, sham n = 27). Biomarkers increased from baseline to cycle 6 of chemotherapy for all patients (median TnT 6 [IQR: 4-9] ng/L to 33 [IQR: 16-36)] ng/L; P ≤ 0.001; cMyC 3 (IQR: 2-5) ng/L to 47 (IQR: 18-49) ng/L; P ≤ 0.001). Mixed-effects regression analysis for repeated measures showed no difference in TnT between the 2 groups (RIC vs sham, mean difference 3.15 ng/L; 95% CI: -0.04 to 6.33; P = 0.053), or cMyC (RIC vs sham, mean difference 4.17 ng/L; 95% CI: -0.12 to 8.45; P = 0.056). There were more MACE and cancer deaths in the RIC group (11 vs 3; HR: 0.25; 95% CI: 0.07-0.90; P = 0.034), with more cancer deaths (8 vs 1; HR: 0.21; 95% CI: 0.04-0.95; P = 0.043) at 1 year. Conclusions: TnT and cMyC significantly increased during anthracycline chemotherapy with 81% having a TnT ≥14 ng/L at cycle 6. RIC did not affect the rise in biomarkers, but there was a small increase in early cancer deaths, possibly related to the greater proportion of patients with metastatic disease randomized to the RIC group (54%vs 37%). (Effect of Remote Ischaemic Conditioning in Oncology Patients [ERIC-ONC]; NCT02471885).

Hypertensive Cardiotoxicity in Cancer Treatment-Systematic Analysis of Adjunct, Conventional Chemotherapy, and Novel Therapies-Epidemiology, Incidence, and Pathophysiology.

Cardiotoxicity is the umbrella term for cardiovascular side effects of cancer therapies. The most widely recognized phenotype is left ventricular dysfunction, but cardiotoxicity can manifest as arrhythmogenic, vascular, myocarditic and hypertensive toxicities. Hypertension has long been regarded as one of the most prevalent and modifiable cardiovascular risk factors in the general population, but its relevance during the cancer treatment journey may be underestimated. Hypertensive cardiotoxicity occurs de novo in a substantial proportion of treated cancer patients. The pathology is incompletely characterized-natriuresis and renin angiotensin system interactions play a role particularly in conventional treatments, but in novel therapies endothelial dysfunction and the interaction between the cancer and cardiac kinome are implicated. There exists a treatment paradox in that a significant hypertensive response not only mandates anti-hypertensive treatment, but in fact, in certain cancer treatment scenarios, hypertension is a predictor of cancer treatment efficacy and response. In this comprehensive review of over 80,000 patients, we explored the epidemiology, incidence, and mechanistic pathophysiology of hypertensive cardiotoxicity in adjunct, conventional chemotherapy, and novel cancer treatments. Conventional chemotherapy, adjunct treatments, and novel targeted therapies collectively caused new onset hypertension in 33-68% of treated patients. The incidence of hypertensive cardiotoxicity across twenty common novel therapies for any grade hypertension ranged from 4% (imatinib) to 68% (lenvatinib), and high grade 3 or 4 hypertension in < 1% (imatinib) to 42% (lenvatinib). The weighted average effect was all-grade hypertension in 24% and grade 3 or 4 hypertension in 8%.

Cardio-oncology for the general physician: 'old' and 'new' cardiovascular toxicities and how to manage them.

Cardio-oncology is the care of cancer patients with cardiovascular disease. The need for a dedicated subspecialty emerged to address heart failure caused by drugs such as anthracyclines and anti-human epidermal growth factor receptor 2 (HER2) therapies, but over time has expanded into an exciting subspecialty with widening horizons. While still dealing with a lot of commonly recognised toxicities, such as heart failure, hypertension and coronary disease, new and revolutionary cancer therapies have been associated with challenging cardiovascular complications, requiring specialist input to manage effectively. Echocardiography is a key investigation, with advanced techniques such as three-dimensional and strain assessment allowing more accurate diagnosis and earlier detection of subtle changes. Cardiac magnetic resonance and biomarkers are useful adjuncts to aid diagnosis and management. With increasing cancer incidence and improved cancer survival rates, it is important that general cardiologists and physicians are aware of cardiac complications associated with cancer and how to manage them.

CAR T Cell Therapy-Related Cardiovascular Outcomes and Management: Systemic Disease or Direct Cardiotoxicity?

CD19-specific chimeric antigen receptor (CAR) T cell therapies have shown remarkable early success in highly refractory and relapsing hematological malignancies. However, this potent therapy is accompanied by significant toxicity. Cytokine release syndrome and neurotoxicity are the most widely reported, but the true extent and characteristics of cardiovascular toxicity remain poorly understood. Thus far, adverse cardiovascular effects observed include sinus tachycardia and other arrhythmias, left ventricular systolic dysfunction, profound hypotension, and shock requiring inotropic support. The literature regarding cardiovascular toxicities remains sparse; prospective studies are needed to define the cardiac safety of CAR T cell therapies to optimally harness their potential. This review summarizes the current understanding of the potential cardiovascular toxicities of CD19-specific CAR T cell therapies, outlines a proposed cardiac surveillance protocol for patients receiving this new treatment, and provides a roadmap of the future direction of cardio-oncology research in this area.

Cardio-Oncology - A new subspecialty with collaboration at its heart.

Cardio-Oncology is the care of cancer patients with cardiovascular disease, overt or occult, already established or acquired during treatment. Cancer patients can present with a variety of cardiovascular problems not all of which are directly related to cancer therapy (medications or radiotherapy). The cardiovascular problems of oncology patients can range from ischaemia to arrhythmias and can also include valve problems and heart failure. As such, within cardiology, teamwork is required with members of different cardiology subspecialties. The way forward will be to adopt a multidisciplinary approach to produce optimal individual care. Close collaboration between cardiology and oncology specialists in a Cardio-Oncology setting can make this happen.

Post-mortem study of the association between cardiac iron and fibrosis in transfusion dependent anaemia.

BACKGROUND: Heart failure related to cardiac siderosis remains a major cause of death in transfusion dependent anaemias. Replacement fibrosis has been reported as causative of heart failure in siderotic cardiomyopathy in historical reports, but these findings do not accord with the reversible nature of siderotic heart failure achievable with intensive iron chelation. METHODS: Ten whole human hearts (9 beta-thalassemia major, 1 sideroblastic anaemia) were examined for iron loading and fibrosis (replacement and interstitial). Five had died from heart failure, 4 had cardiac transplantation for heart failure, and 1 had no heart failure (death from a stroke). Heart samples iron content was measured using atomic emission spectroscopy. Interstitial fibrosis was quantified by computer using picrosirius red (PSR) staining and expressed as collagen volume fraction (CVF) with normal value for left ventricle <3%. RESULTS: The 9 hearts affected by heart failure had severe iron loading with very low T2* of 5.0 ± 2.0 ms (iron concentration 8.5 ± 7.0 mg/g dw) and diffuse granular myocardial iron deposition. In none of the 10 hearts was significant macroscopic replacement fibrosis present. In only 2 hearts was interstitial fibrosis present, but with low CVF: in one patient with no cardiac siderosis (death by stroke, CVF 5.9%) and in a heart failure patient (CVF 2%). In the remaining 8 patients, no interstitial fibrosis was seen despite all having severe cardiac siderosis and heart failure (CVF 1.86% ±0.87%). CONCLUSION: Replacement cardiac fibrosis was not seen in the 9 post-mortem hearts from patients with severe cardiac siderosis and heart failure leading to death or transplantation, which contrasts markedly to historical reports. Minor interstitial fibrosis was also unusual and very limited in extent. These findings accord with the potential for reversibility of heart failure seen in iron overload cardiomyopathy. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT00520559.

Anthracycline Chemotherapy and Cardiotoxicity.

Anthracycline chemotherapy maintains a prominent role in treating many forms of cancer. Cardiotoxic side effects limit their dosing and improved cancer outcomes expose the cancer survivor to increased cardiovascular morbidity and mortality. The basic mechanisms of cardiotoxicity may involve direct pathways for reactive oxygen species generation and topoisomerase 2 as well as other indirect pathways. Cardioprotective treatments are few and those that have been examined include renin angiotensin system blockade, beta blockers, or the iron chelator dexrazoxane. New treatments exploiting the ErbB or other novel pro-survival pathways, such as conditioning, are on the cardioprotection horizon. Even in the forthcoming era of targeted cancer therapies, the substantial proportion of today's anthracycline-treated cancer patients may become tomorrow's cardiac patient.

Effect of Remote Ischaemic Conditioning in Oncology Patients Undergoing Chemotherapy: Rationale and Design of the ERIC-ONC Study--A Single-Center, Blinded, Randomized Controlled Trial.

Cancer survival continues to improve, and thus cardiovascular consequences of chemotherapy are increasingly important determinants of long-term morbidity and mortality. Conventional strategies to protect the heart from chemotherapy have important hemodynamic or myelosuppressive side effects. Remote ischemic conditioning (RIC) using intermittent limb ischemia-reperfusion reduces myocardial injury in the setting of percutaneous coronary intervention. Anthracycline cardiotoxicity and ischemia-reperfusion injury share common biochemical pathways in cardiomyocytes. The potential for RIC as a novel treatment to reduce subclinical myocyte injury in chemotherapy has never been explored and will be investigated in the Effect of Remote Ischaemic Conditioning in Oncology (ERIC-ONC) trial (clinicaltrials.gov NCT 02471885). The ERIC-ONC trial is a single-center, blinded, randomized, sham-controlled study. We aim to recruit 128 adult oncology patients undergoing anthracycline-based chemotherapy treatment, randomized in a 1:1 ratio into 2 groups: (1) sham procedure or (2) RIC, comprising 4, 5-minute cycles of upper arm blood pressure cuff inflations and deflations, immediately before each cycle of chemotherapy. The primary outcome measure, defining cardiac injury, will be high-sensitivity troponin-T over 6 cycles of chemotherapy and 12 months follow-up. Secondary outcome measures will include clinical, electrical, structural, and biochemical endpoints comprising major adverse cardiovascular clinical events, incidence of cardiac arrhythmia over 14 days at cycle 5/6, echocardiographic ventricular function, N-terminal pro-brain natriuretic peptide levels at 3 months follow-up, and changes in mitochondrial DNA, micro-RNA, and proteomics after chemotherapy. The ERIC-ONC trial will determine the efficacy of RIC as a novel, noninvasive, nonpharmacological, low-cost cardioprotectant in cancer patients undergoing anthracycline-based chemotherapy.

Calibration of myocardial T2 and T1 against iron concentration.

BACKGROUND: The assessment of myocardial iron using T2* cardiovascular magnetic resonance (CMR) has been validated and calibrated, and is in clinical use. However, there is very limited data assessing the relaxation parameters T1 and T2 for measurement of human myocardial iron. METHODS: Twelve hearts were examined from transfusion-dependent patients: 11 with end-stage heart failure, either following death (n=7) or cardiac transplantation (n=4), and 1 heart from a patient who died from a stroke with no cardiac iron loading. Ex-vivo R1 and R2 measurements (R1=1/T1 and R2=1/T2) at 1.5 Tesla were compared with myocardial iron concentration measured using inductively coupled plasma atomic emission spectroscopy. RESULTS: From a single myocardial slice in formalin which was repeatedly examined, a modest decrease in T2 was observed with time, from mean (± SD) 23.7 ± 0.93 ms at baseline (13 days after death and formalin fixation) to 18.5 ± 1.41 ms at day 566 (p<0.001). Raw T2 values were therefore adjusted to correct for this fall over time. Myocardial R2 was correlated with iron concentration [Fe] (R2 0.566, p<0.001), but the correlation was stronger between LnR2 and Ln[Fe] (R2 0.790, p<0.001). The relation was [Fe] = 5081•(T2)-2.22 between T2 (ms) and myocardial iron (mg/g dry weight). Analysis of T1 proved challenging with a dichotomous distribution of T1, with very short T1 (mean 72.3 ± 25.8 ms) that was independent of iron concentration in all hearts stored in formalin for greater than 12 months. In the remaining hearts stored for <10 weeks prior to scanning, LnR1 and iron concentration were correlated but with marked scatter (R2 0.517, p<0.001). A linear relationship was present between T1 and T2 in the hearts stored for a short period (R2 0.657, p<0.001). CONCLUSION: Myocardial T2 correlates well with myocardial iron concentration, which raises the possibility that T2 may provide additive information to T2* for patients with myocardial siderosis. However, ex-vivo T1 measurements are less reliable due to the severe chemical effects of formalin on T1 shortening, and therefore T1 calibration may only be practical from in-vivo human studies.

On T2* magnetic resonance and cardiac iron.

BACKGROUND: Measurement of myocardial iron is key to the clinical management of patients at risk of siderotic cardiomyopathy. The cardiovascular magnetic resonance relaxation parameter R2* (assessed clinically via its reciprocal, T2*) measured in the ventricular septum is used to assess cardiac iron, but iron calibration and distribution data in humans are limited. METHODS AND RESULTS: Twelve human hearts were studied from transfusion-dependent patients after either death (heart failure, n=7; stroke, n=1) or transplantation for end-stage heart failure (n=4). After cardiovascular magnetic resonance R2* measurement, tissue iron concentration was measured in multiple samples of each heart with inductively coupled plasma atomic emission spectroscopy. Iron distribution throughout the heart showed no systematic variation between segments, but epicardial iron concentration was higher than in the endocardium. The mean ± SD global myocardial iron causing severe heart failure in 10 patients was 5.98 ± 2.42 mg/g dry weight (range, 3.19 to 9.50 mg/g), but in 1 outlier case of heart failure was 25.9 mg/g dry weight. Myocardial ln[R2*] was strongly linearly correlated with ln[Fe] (R²=0.910, P<0.001), leading to [Fe]=45.0×(T2*)⁻¹·²² for the clinical calibration equation with [Fe] in milligrams per gram dry weight and T2* in milliseconds. Midventricular septal iron concentration and R2* were both highly representative of mean global myocardial iron. CONCLUSIONS: These data detail the iron distribution throughout the heart in iron overload and provide calibration in humans for cardiovascular magnetic resonance R2* against myocardial iron concentration. The iron values are of considerable interest in terms of the level of cardiac iron associated with iron-related death and indicate that the heart is more sensitive to iron loading than the liver. The results also validate the current clinical practice of monitoring cardiac iron in vivo by cardiovascular magnetic resonance of the midseptum.

Right ventricular volumes and function in thalassemia major patients in the absence of myocardial iron overload.

AIM: We aimed to define reference ranges for right ventricular (RV) volumes, ejection fraction (EF) in thalassemia major patients (TM) without myocardial iron overload. METHODS AND RESULTS: RV volumes, EF and mass were measured in 80 TM patients who had no myocardial iron overload (myocardial T2* > 20 ms by cardiovascular magnetic resonance). All patients were receiving deferoxamine chelation and none had evidence of pulmonary hypertension or other cardiovascular comorbidity. Forty age and sex matched healthy non-anemic volunteers acted as controls. The mean RV EF was higher in TM patients than controls (males 66.2 +/- 4.1% vs 61.6 +/- 6%, p = 0.0009; females 66.3 +/- 5.1% vs 62.6 +/- 6.4%, p = 0.017), which yielded a raised lower threshold of normality for RV EF in TM patients (males 58.0% vs 50.0% and females 56.4% vs 50.1%). RV end-diastolic volume index was higher in male TM patients (mean 98.1 +/- 17.3 mL vs 88.4 +/- 11.2 mL/m2, p = 0.027), with a higher upper limit (132 vs 110 mL/m2) but this difference was of borderline significance for females (mean 86.5 +/- 13.6 mL vs 80.3 +/- 12.8 mL/m2, p = 0.09, with upper limit of 113 vs 105 mL/m2). The cardiac index was raised in TM patients (males 4.8 +/- 1.0 L/min vs 3.4 +/- 0.7 L/min, p < 0.0001; females 4.5 +/- 0.8 L/min vs 3.2 +/- 0.8 L/min, p < 0.0001). No differences in RV mass index were identified. CONCLUSION: The normal ranges for functional RV parameters in TM patients with no evidence of myocardial iron overload differ from healthy non-anemic controls. The new reference RV ranges are important for determining the functional effects of myocardial iron overload in TM patients.

Normalized left ventricular volumes and function in thalassemia major patients with normal myocardial iron.

PURPOSE: To determine the reference range in thalassemia major (TM) for left ventricular (LV) function. MATERIALS AND METHODS: We used cardiovascular magnetic resonance (CMR) to measure heart volumes and function in 81 TM patients with normal myocardial T2* measurements (T2* > 20 msec) and by inference without excess myocardial iron. Forty age- and gender-matched healthy controls were also studied. RESULTS: Resting LV volumes and function normalized to body surface area differed significantly between TM patients and controls. The lower limit and the mean for ejection fraction (EF) were higher in TM patients (males 59 vs. 55%, mean 71% vs. 65%; females 63 vs. 59%, mean 71% vs. 67%; both P < 0.001). The upper limit and mean for end-diastolic volume index were higher in TM patients (males 152 vs. 105 mL/m(2), mean 97 vs. 84 mL/m(2); females 121 vs. 99 mL/m(2), mean 87 vs. 79 mL/m(2); both P < 0.05). In TM patients the cardiac index (P < 0.001) was increased. CONCLUSION: At rest, TM patients with a normal myocardial T2* have different "normal" values for LV volume and function parameters compared to controls, and this has the potential to lead to a misdiagnosis of cardiomyopathy. We present new reference "normal" ranges in TM to alleviate this problem.

Development of thalassaemic iron overload cardiomyopathy despite low liver iron levels and meticulous compliance to desferrioxamine.

It is believed that myocardial iron deposition and the resultant cardiomyopathy only occur in the presence of severe liver iron overload. Using cardiovascular magnetic resonance, it is now possible to assess myocardial and liver iron levels as well as cardiac function in the same scan, allowing this supposition to be examined. We describe a patient with progressive myocardial iron deposition and the development of early iron overload cardiomyopathy despite excellent compliance to standard subcutaneous desferrioxamine, minimal liver iron and well-controlled serum ferritin levels. These indirect markers remained far below the thresholds conventionally believed to be associated with increased cardiac risk.

Left ventricular diastolic function compared with T2* cardiovascular magnetic resonance for early detection of myocardial iron overload in thalassemia major.

PURPOSE: To compare left ventricular (LV) diastolic function with myocardial iron levels in beta thalassemia major (TM) patients, using cardiovascular magnetic resonance (CMR). MATERIALS AND METHODS: We studied 67 regularly transfused patients with TM and 22 controls matched for age, gender, and body surface area. The early peak filling rate (EPFR) and atrial peak filling rate (APFR) were determined from high-temporal-resolution ventricular volume-time curves. Myocardial iron estimation was achieved using myocardial T2* measurements. RESULTS: Myocardial iron loading was found in 46 TM patients (69%), in whom the EPFR correlated poorly with T2* (r = -0.20, P = 0.19). The APFR (r = 0.49, P < 0.001) and EPFR/APFR ratio (r = -0.62, P < 0.001) correlated better with T2*. The sensitivity of the diastolic parameters for detecting myocardial iron loading ranged from 4% (EPFR and APFR) to 17% (EPFR/APFR ratio). CONCLUSION: Myocardial iron overload results in diastolic myocardial dysfunction, but low sensitivity limits the use of a single estimation for early detection of iron overload, for which T2* has a superior categorical limit of normality.

Myocardial iron clearance during reversal of siderotic cardiomyopathy with intravenous desferrioxamine: a prospective study using T2* cardiovascular magnetic resonance.

Heart failure from iron overload causes 71% of deaths in thalassaemia major, yet reversal of siderotic cardiomyopathy has been reported. In order to determine the changes in myocardial iron during treatment, we prospectively followed thalassaemia patients commencing intravenous desferrioxamine for iron-induced cardiomyopathy during a 12-month period. Cardiovascular magnetic resonance assessments were performed at baseline, 3, 6 and 12 months of treatment, and included left ventricular (LV) function and myocardial and liver T2*, which is inversely related to iron concentration. One patient died. The six survivors showed progressive improvements in myocardial T2* (5.1 +/- 1.9 to 8.1 +/- 2.8 ms, P = 0.003), liver iron (9.6 +/- 4.3 to 2.1 +/- 1.5 mg/g, P = 0.001), LV ejection fraction (52 +/- 7.1% to 63 +/- 6.4%, P = 0.03), LV volumes (end diastolic volume index 115 +/- 17 to 96 +/- 3 ml, P = 0.03; end systolic volume index 55 +/- 16 to 36 +/- 6 ml, P = 0.01) and LV mass index (106 +/- 14 to 95 +/- 13, P = 0.01). Iron cleared more slowly from myocardium than liver (5.0 +/- 3.3% vs. 39 +/- 23% per month, P = 0.02). These prospective data confirm that siderotic heart failure is often reversible with intravenous iron chelation with desferrioxamine. Myocardial T2* improves in concert with LV volumes and function during recovery, but iron clearance from the heart is considerably slower than from the liver.

Comparison of effects of oral deferiprone and subcutaneous desferrioxamine on myocardial iron concentrations and ventricular function in beta-thalassaemia.

BACKGROUND: Despite the introduction of the parenteral iron chelator desferrioxamine more than 30 years ago, 50% of patients with thalassaemia major die before the age of 35 years, predominantly from iron-induced heart failure. The only alternative treatment is oral deferiprone, but its long-term efficacy on myocardial iron concentrations is unknown. METHODS: We compared myocardial iron content and cardiac function in 15 patients receiving long-term deferiprone treatment with 30 matched thalassaemia major controls who were on long-term treatment with desferrioxamine. Myocardial iron concentrations were measured by a new magnetic-resonance T2* technique, which shows values inversely related to tissue iron concentration. FINDINGS: The deferiprone group had significantly less myocardial iron (median 34.0 ms vs 11.4 ms, p=0.02) and higher ejection fractions (mean 70% [SD 6.5] vs 63% [6.9], p=0.004) than the desferrioxamine controls. Excess myocardial iron (T2* <20 ms) was less common in the deferiprone group than in the desferrioxamine controls (four [27%] vs 20 [67%], p=0.025), as was severe (T2* <10 ms) iron overload (one [7%] vs 11 [37%], p=0.04). The odds ratio for excess myocardial iron in the desferrioxamine controls versus the deferiprone group was 5.5 (95% CI 1.2-28.8). INTERPRETATION: Conventional chelation treatment with subcutaneous desferrioxamine does not prevent excess cardiac iron deposition in two-thirds of patients with thalassaemia major, placing them at risk of heart failure and its complications. Oral deferiprone is more effective than desferrioxamine in removal of myocardial iron.