Cardiac toxicities of fluoropyrimidine chemotherapy: A literature review and evaluation of current practice at a large U.K. cancer center

72

Background: Fluoropyrimidine chemotherapy is a mainstay of the adjuvant and palliative management of colorectal cancer. Cardiac toxicities—including angina, myocardial infarction and arrhythmias—are uncommon complications thought to be mediated by coronary vasospasm. Although potentially life-threatening, they remain poorly described and consensus guidelines regarding patient selection are lacking. To assess current understanding of this toxicity, we performed a literature review of the topic. We then evaluated fluoropyrimidine use at a large UK cancer center to investigate current practice. Methods: MEDLINE, EMBASE and the Cochrane central register of controlled trials were searched to March 1 2021 using the search terms (fluorouracil OR capecitabine) AND—separately—cardiotoxicity, heart disease, and rechallenge*. Original research articles in English were included and their findings summarised. The case notes of all patients who underwent surgery for pathological stage III colon cancer between January 1 2017 and December 31 2019 at Leeds Cancer Centre were reviewed. The proportion of patients who experienced cardiac toxicity during adjuvant chemotherapy was assessed. The proportion of patients who were not offered adjuvant chemotherapy due to cardiac risk was identified. Results: The three search strategies identified 582, 55 and 21 citations respectively, of which 28, 7 and 7 full texts were retrieved for further evaluation following review of titles and abstracts. The reported incidence of fluoropyrimidine cardiotoxicity varied widely, as did its definition. Over half of toxicity cases described were ischaemic. Reported risk factors included those for coronary artery disease, although this was not a consistent finding. 125 patients underwent surgery for stage III colon cancer in the study period of whom 81 (65%) received adjuvant chemotherapy. 2 (2.5%) patients failed to complete adjuvant treatment due to cardiac toxicity (angina; cardiac arrest). Pre-existing cardiovascular disease was cited as a reason for not offering adjuvant chemotherapy in 13 of 44 cases (30%). Conclusions: Review of the literature revealed a poor evidence base to guide treatment decisions regarding fluoropyrimidine chemotherapy and cardiac risk. Rates of cardiac toxicity at our center were within expected limits. A number of patients were denied adjuvant chemotherapy due to perceived cardiac risk. A clearer understanding of the pathophysiology and management of fluoropyrimidine cardiotoxicity is urgently required to avoid unnecessarily denying patients effective anti-cancer therapy.

Prospective longitudinal characterisation of the relationship between diabetes and cardiac remodeling

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): British Heart Foundation Clinical Research Training Fellowship and Wellcome Trust

Background

Cardiovascular disease represents the primary cause of death in patients with type 2 diabetes (T2D). Heart failure (HF) is the commonest initial presentation of cardiovascular disease in T2D. Development of HF in patients with T2D is associated with a 4 to 6-fold increase in mortality, making the prevention of cardiac dysfunction an important goal. The long-term impact of T2D on cardiac function in the absence of cardiovascular disease is unknown. This is the first prospective longitudinal study utilising cardiovascular magnetic resonance (CMR) to evaluate the impact of T2D on cardiac remodeling.

Objectives

To determine longitudinal changes in the phenotypic expression of heart disease in diabetes over 6 years, and examine the association of baseline blood and imaging biomarkers with remodeling over time in patients who remained free of cardiovascular/clinical events, and to report clinical outcomes in the entire cohort.

Methods

100 asymptomatic T2D patients with no history of cardiovascular disease or hypertension were previously studied. Biventricular volumes, function, and myocardial strain were assessed by CMR and blood biomarkers taken. 6-year follow-up CMR was repeated in those without interim cardiovascular events.

Results

Of the 100 patients, 78 could be contacted for follow-up. 29 participants experienced cardiovascular/clinical events over 6 years. 32 patients who were asymptomatic and without events received follow-up CMR. The major adverse cardiovascular event rate (MI, angina, revascularisation, stroke, death) during the 6-year follow-up period, including the patients with a silent MI, amounted to 25% in this study with an overall clinical event rate of 35%.

 There were no significant changes in BP, BMI or HBA1c between baseline and follow-up (Table 1). Left ventricular end-diastolic-volume(p = 0.005), mass (p = 0.01), ejection fraction (p = 0.0001), and right ventricular end-diastolic-volume(p = 0.03) and ejection fraction(p = 0.003) reduced over time (Figure 2 and Table 1). Baseline plasma high-sensitivity cardiac-troponin-T (hs-cTnT) (R=-0.44; p = 0.01) was significantly associated with change in left ventricular ejection fraction over time.

Conclusions

Even in the absence of overt clinical CAD, significant valvular disease, uncontrolled hypertension or change in BMI, T2D results in significant reductions in cardiac size and biventricular systolic function over time. The major adverse cardiovascular event rate (MI, angina, revascularisation, stroke, death) during the 6-year follow-up period was high in diabetes patients (25%). Plasma biomarker hs-cTnT measured at baseline was associated with change in LV systolic function over the 6-year follow-up period. hs-cTnT could potentially have a significant utility as a risk-predicting tool for cardiac dysfunction in T2D patients.

Detrimental immediate and long-term clinical effects of right ventricular pacing in patients with myocardial fibrosis

Funding Acknowledgements

Type of funding sources: None.

Background

Long-term right ventricular (RV) pacing leads to heart failure or a decline in left ventricular (LV) function in up to a fifth of patients.

Objectives

We aimed to establish whether patients with focal fibrosis detected on late gadolinium enhancement cardiovascular magnetic resonance (CMR) have deterioration in LV function after RV pacing.

Methods

We recruited 110 patients (84 in final analysis) into two observational CMR studies. Patients (n = 34) with a dual chamber device and preserved atrioventricular (AV) conduction underwent CMR in two asynchronous pacing modes (AOO & DOO) to compare intrinsic conduction with RV pacing. Patients (n = 50) with high-grade AV block underwent CMR before and 6 months after pacemaker implantation to investigate the long-term effects of RV pacing.

Results: The three key findings were

1) Initiation of RV pacing in patients with fibrosis, compared to those without, was associated with greater immediate changes in both LV end-systolic volume index (LVESVi) (5.3 ± 3.5 vs 2.1 ± 2.4 mL/m2; p < 0.01) and LV ejection fraction (LVEF) (-5.7 ± 3.4% vs -3.2 ± 2.6%; p = 0.02); 2) Long-term RV pacing in patients with fibrosis, compared to those without, was associated with greater changes in LVESVi (8.0 ± 10.4 vs -0.6 ± 7.3 mL/m2; p = 0.008) and LVEF (-12.3 ± 7.9 vs -6.7 ± 6.2%; p = 0.012); 3) Patients with fibrosis did not experience an improvement in quality of life, biomarkers or functional class after pacemaker implantation.

Conclusions

Fibrosis detected on CMR is associated with immediate and long-term deterioration in LV function following RV pacing and could be used to identify those at risk of heart failure prior to pacemaker implantation.

Characteristics before and after pacing Study 1 No fibrosis (n = 16) Fibrosis (n = 18) AOO DOO p-value AOO DOO p-value LVEDVi - mL/m² 66 ± 13 66 ± 12 0.67 78 ± 14 79 ± 13 0.34 LVESVi - mL/m² 30 ± 10 32 ± 9 0.003 38 ± 11 43 ± 12 <0.001 LVEF - % 56 ± 6 53 ± 5 <0.001 52 ± 8 47 ± 9 <0.001 Mechanical Dyssynchrony index - ms 61 ± 17 71 ± 25 0.07 81 ± 18 89 ± 21 0.04 Study 2 No fibrosis (n = 19) Fibrosis (n = 31) Pre-PPM Post-PPM p-value Pre-PPM Post-PPM p-value LVEDVi -mL/m² 88 ± 21 73 ± 14 <0.001 90 ± 18 83 ± 21 0.007 LVESVi -mL/m² 35 ± 9 34 ± 9 0.71 41 ± 14 49 ± 21 0.001 LVEF - % 60 ± 5 54 ± 7 <0.001 56 ± 8 43 ± 12 <0.001 Mechanical Dyssynchrony index - ms 70 ± 29 81 ± 22 0.15 84 ± 30 98 ± 31 0.03 Abstract Figure. Mechanism for heart failure after pacing

Partial normalisation of cardiac mechanics with active CRT in patients with chronic failure: a novel application of 3.0T CMR

Introduction

Cardiac resynchronisation therapy (CRT) is a routine treatment for chronic heart failure (CHF) with reduced ejection fraction and conduction delay to improve prognosis. Cardiac mechanics in patients with CHF are believed to be altered from controls based on invasive and echocardiographic based data. Technological advancements in cardiac magnetic resonance (CMR) and devices enable investigation of the cardiac response to CRT over a range of heart rates.

Methods

Patients with a CRT-D device were enrolled from heart failure clinics at Leeds General Infirmary, UK. After a MRI safety assessment, a baseline device check was conducted by a cardiac physiologist. Left ventricular (LV) volumes and systolic BP were measured at baseline and heart rates of 75, 90, 100, 115, 125, and 140 (randomised order) with CRT active and intrinsic conduction. All scans were conducted using a 3.0 T Siemens Prisma MRI scanner. Analysis of the scans used commercially available software. LV contractility was derived as a ratio of the LV end systolic volume and systolic BP. A post scan device interrogation was conducted to assess for scanning safety. Control participants with a 3.0T MR-conditional dual chamber pacemakers completed a similar protocol.

Results

Scanning was conducted in 17 CRT patients and 13 controls with a pre and post device and lead interrogation. No patient experienced symptoms related to scanning or device failure. The mean LV ejection fraction at baseline in the CRT cohort was 33.7±12.9%. Left ventricular ejection fraction fell across both cohorts as paced heart rate increased with reduced deterioration in control patients and those with CRT active. Peak LV cardiac output was significantly higher during active CRT (p<0.05). LV contractility was relatively static with CRT disabled (r2=0.13, p=0.38) and improved with CRT active (r2=0.91, p=0.01) and in controls (r2=0.74, p=0.01). Peak LV strain occurred at 100bpm during active CRT and in control patients whereas CRT disabled resulted in earlier deterioration.

Conclusion

We have demonstrated improvements in cardiac output and contractility consequent to active CRT using 3.0T CMR and subsequently validated via strain analysis. CRT appears to partially normalise cardiac mechanics across the range of heart rates studied. Further work is required to explore this phenomenon on a cellular or metabolic level.

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): AK is supported by an unconditional grant provided by Medtronic

P1236Revealing cardiac mechanics with CMR whilst CRT is active: the first step

Introduction

Cardiac resynchronisation therapy (CRT) is a routine treatment for heart failure with reduced ejection fraction and conduction delay to improve symptoms and prognosis. Technological advancements both in cardiac magnetic resonance (CMR) and devices (MRI-conditional modes) now enable investigation of the haemodynamic response to CRT over a range of heart rates.

Methods

Patients with a CRT-D device were enrolled from heart failure clinics at a single tertiary centre. A complete device system assessment and baseline device check was conducted to ensure MRI compatibility and suitability. Left ventricular (LV) volumes and systolic blood pressure were measured at baseline and heart rates of 75, 90, 100, 115, 125, and 140 bpm (randomised order) with CRT active and intrinsic conduction (AOO). MRI conditional mode parameters were replicated through standard parameter modification to ensure biventricular pacing during CRT active scans. All scans were conducted using a 3.0 T Siemens Prisma MRI scanner with analysis on commercially available software. Contractility was derived from the systolic blood pressure and left ventricular end systolic volume. A post scan device and lead assessment was conducted to assess for scanning safety.

Results

Scanning was conducted in 22 patients (safety cohort). Post scan battery voltage reduced by 2.9±1.0%. Mean change in atrial, right ventricular and left ventricular lead impedance was 0.5±0.06%, 3.0±0.04% and −1.7±0.05% respectively. Mean change in atrial, right ventricular and left ventricular pacing threshold was 0.0±0.3%, 8.3±0.3% and 5.6±0.3%. No patient experienced symptoms related to scanning or device failure.

Preliminary data for patients with CRT on and off have been analysed (paired analysis cohort, n=8, 6 men). Mean age was 71.1±8.2, aetiology was primarily ischaemic (62.5%) with the remainder dilated cardiomyopathy. The mean LV ejection fraction at baseline was 29.4±12.9%. Biventricular pacing led to acute improvements in ejection fraction (p=0.005), left ventricular cardiac output (p<0.0001) and contractility (p=0.05) over the entire range of heart rates studied. We also noted an improvement in the force frequency relationship during biventricular pacing with a higher peak contractility (p=0.05), a higher heart rate at which this occurred (HR=130) and a generally up sloping relationship when compared with intrinsic conduction.

Conclusion

We have demonstrated for the first time, the mechanistic improvements in cardiac contractility consequent to CRT using CMR and also that MRI scans of conditional devices can be safe with CRT active.

Acknowledgement/Funding

Dr A Koshy is conducting a PhD supported by grant from Medtronic. Dr Klaus Witte has received honoraria from Medtronic

Current Venous Thromboembolism Prevention Practices Following Endovascular Electrophysiological Procedures in the UK: A retrospective study

Objectives

This study aimed to evaluate the incidence of venous thromboembolism (VTE) cases at the Leeds General Infirmary, Leeds, UK, as well as to survey current VTE practices and preventative strategies at other UK-based electrophysiology (EP) centres.

Methods

This retrospective study involved all patients who underwent EP studies at Leeds General Infirmary from January 2014 to December 2016. In addition, a telephone survey was conducted of 35 other UK-based EP centres.

Results

Of 1,020 patients who underwent EP studies at Leeds General Infirmary, 0.3% developed a post-procedural VTE. In addition, 28 other EP centres were surveyed (response rate: 80%), of which 18% reported VTE cases in the last two years. There were wide variations in VTE prevention strategies and the use of post-procedural thromboprophylaxis.

Conclusion

Despite the low incidence of VTE cases, many UK centres continue to experience this complication with no consensus on optimal preventative strategies. As current VTE guidelines do not recommend antithrombotics after EP studies, further research is needed.

Acute myocarditis secondary to cardiac tuberculosis: a case report

Isolated myocardial involvement in tuberculosis is exceedingly rare but there are reports it can present with sudden cardiac death, atrioventricular block, ventricular arrhythmias or congestive cardiac failure. We report the case of a 33-year-old male, of South Asian descent, who presented with chest pain, shortness of breath and an abnormal ECG. The patient had no significant past medical history and coronary angiogram showed no evidence of coronary artery disease. Of note, the patient had recently been discharged from a local district hospital with an episode of myocarditis. The patient was found to be severely hypoxic with evidence of severe biventricular failure on echocardiography. Computed tomography of the chest demonstrated hilar lymphadenopathy, and the differential diagnosis was thought to be tuberculosis or sarcoidosis. A TB Quantiferon gold test performed at the district hospital was positive; however, fine needle aspiration was negative for acid-fast bacilli. Despite aggressive diuresis, the patient became increasingly hypoxic and suffered a cardiac arrest. Post-mortem confirmed a diagnosis of myocardial tuberculosis – a rare case of acute decompensated heart failure.