Key changes in indices of myocardial work in cardiometabolic disease states

Background

Hypertension (HTN) and diabetes mellitus (DM) are prevalent cardiovascular disease states which have been shown to be associated with adverse cardiac remodelling and subclinical myocardial dysfunction. Myocardial work (MW) indices are novel non-invasive measures of left ventricular (LV) function. We aimed to characterise key differences in MW indices in patients with these conditions.

Methods

Outpatients with HTN and DM undergoing transthoracic echocardiography (TTE; 2016–2019) at our institution were assessed and compared to healthy controls. Only patients without cardiac disease with normal diastolic parameters on TTE were recruited. Patients with impaired LV function, cardiac ischaemia or arrhythmia, structural and valvular heart disease or poor-quality images were excluded. Recruited patients were stratified into 3 groups (Group1: Healthy Controls; Group 2: HTN; Group 3: HTN-DM). MW assessment was performed using GE E-95 EchoPac v2.2 system.

Results

Three hundred patients (57.3±17.4y, 51% female) were recruited. HTN and HTN-DM patients were associated with higher resting systolic blood pressure (SBP), indexed LV mass (LVMI), e' and E/e' compared to controls but no differences were noted in these parameters between HTN and HTN-DM. Global myocardial work index (GWI) was higher in HTN patients compared to Controls but not different compared to HTN-DM. Of interest, HTN-DM patients had higher global myocardial wasted work (GWW) and lower global myocardial work efficiency (GWE) compared to HTN patients and Controls.

Conclusions

MW indices may be a sensitive tool for the detection of subclinical changes in cardiac function in cardiometabolic disease states.

Funding Acknowledgement

Type of funding source: None

Effect of prevalent atrial fibrillation on cardiovascular outcomes in patients with chronic kidney disease

Background

The global increase in incidence and prevalence of chronic kidney disease (CKD) is associated with a parallel rise in co-morbid atrial fibrillation (AF). Concurrent presence of both conditions increases clinical complexity and may portend poor outcomes in this population.

Purpose

The aim of our study was to assess the impact of prevalent AF on mortality and cardiovascular outcomes in patients with CKD.

Methods

Consecutive patients with CKD (Stages 2 to 5) attending the Nephrology outpatient clinics in our health district between Jan 2007-Dec 2017 were retrospectively evaluated. Detailed appraisal of patient demographics, anthropometrics, clinical co-morbidities (including aetiology, stage and management of CKD) and pharmacotherapeutics was undertaken. These patients were followed for up to ten years for the composite outcomes of all-cause death and major adverse cardiovascular events (MACE). We excluded patients with incomplete clinical data and patients with concomitant medical co-morbidity limiting lifespan to <6 months.

Results

2008 patients (63.61±17.17 yrs; 55.7% men) were assessed. The mean eGFR was 37.53±21.88 mL/min/m2. Patients with prevalent AF (n=440, 22%) were older (p<0.01), with lower eGFR (p<0.01) and higher rates of renal replacement therapy (p<0.01). They also had a greater burden of coronary disease (p<0.01), heart failure (p<0.01), stroke (p<0.01), obstructive sleep apnoea (p<0.01), chronic obstructive pulmonary disease (p<0.01), anaemia (p<0.01) and obesity (p<0.01). Over the mean follow-up period of 44.04±34.96 months, 832 patients met the composite outcome (410 all-cause death, 422 MACE). On log rank tests, prevalent AF was a predictor of the composite outcome (Figure 1; p<0.01) and remained an independent predictor of all-cause death and MACE on multivariate analysis (HR 1.65; 95% CI 1.24–2.21, p<0.01).

Conclusions

Prevalent AF is an independent predictor of all-cause death and MACE in patients with CKD.

Figure 1. Kaplan Meier Curve

Funding Acknowledgement

Type of funding source: None

Abstract 6474: FAT1 and CASP8 co-mutations are associated with poor prognosis in HPV negative head and neck squamous cell carcinoma

INTRODUCTION: FAT1 alterations with somatic mutations or deletions are observed in head and neck squamous cell carcinomas (HNSCC). These alterations lead to loss of function of FAT1. FAT1 loss of function was known to be associated with aberrant Wnt activation, cell migration and invasion. In this study, we present analysis and outcomes of co-mutations seen in FAT1-mutation positive HNSCC.

METHODS: TCGA data were analyzed for mutation, gene expression data and overall survival. We examined mutation data in 415 HPV negative samples and 72 HPV positive samples. The Fisher's Exact test was used to determine if differences in mutation frequency existed between the different cohorts. Mantel-Cox method was used for overall survival (OS) comparison between the cohorts.

RESULTS: FAT1 somatic mutation was the third most commonly mutated gene in HPV-negative HNSCC while it was not common in HPV-positive HNSCC. FAT1 mutation was seen in 25.8% of HPV negative HNSCC (107/415), while 4.2% (3/72) HPV positive HNSCC had FAT1 mutation. We then analyzed the frequency of co-mutations in FAT1-mutated HPV-negative HNSCC. CDKN2A, NOTCH1, CASP8, FBXW7, ZFHX4, HRAS, DCC, ATR mutations were more common in FAT1-mutated cancers. CASP8 mutation was seen in 24.30% (26 out of 107 samples) of FAT1-mutations positive HPV negative HNSCC, while it was less common in FAT1-mutation negative HNSCC (9.08% 28/308) (P=0.002). The patients with FAT1 and CASP8 co-mutation were associated with shorter overall survival when compared with patients with FAT1-mutation (19.8 months vs 52.3 months P=0.02). FAT1 only or CASP8 only mutation without co-mutation did not affect survival. To determine the mutation impact of the FAT1 and CASP8 mutations in HNSCC, differentially expressed genes between mutated and non-mutated genes were analyzed in HNSCC. CASP8 mutation was the top gene among the genes with somatic mutation in HNSCC and associated with gene expression changes in more than 6000 genes. FAT1 was ranked 11th resulting in differential gene expression in more than 1000 genes.

DISCUSSION: FAT1 somatic mutations are commonly seen in HPV negative HNSCC. We have demonstrated for the first time that CASP8 and FAT1 co-mutations are associated with poor prognosis with decreased overall survival in HPV negative HNSCC. Both CASP8 and FAT1 mutations are among the top genes with mutation impact on differential gene expression in HNSCC suggesting significance of these mutations in HNSCC.

Citation Format: Emrullah Yilmaz, David Lee, Andrew Cowan, Gregory Gan, Michelle Ozbun, Yan Guo. FAT1 and CASP8 co-mutations are associated with poor prognosis in HPV negative head and neck squamous cell carcinoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6474.

The development and electronic delivery of case-based learning using a fast healthcare interoperability resource system

HL7 International’s Fast Healthcare Interoperability Resources (FHIR) standard provides a common format for sharing health data (eg, FHIR resources) and a RESTful Application Programming Interface (eg, FHIR API) for accessing those resources via a FHIR server connected to an electronic health record system or any other system storing clinical data. Substitutable Medical Applications and Reusable Technologies (SMART) leverages FHIR to create an electronic health record (EHR) agnostic app platform. It utilizes the OAuth standard to provide for authorization and authentication. This paper describes the development and informal evaluation of Case Based Learning on FHIR (CBL on FHIR), a prototype EHR-connected FHIR/SMART platform to provide interactive digital cases for use in medical education. The project goals were to provide a more interactive form of CBL than is possible on paper to more realistically simulate clinical decision making and to expose medical students to modern informatics systems and tools for use in patient care.

P1709 Left atrial strain: a novel prognostic marker in patients with chronic kidney disease

Funding Acknowledgements

Nil

Background and objectives

Patients with chronic kidney disease (CKD) are at increased risk of adverse cardiovascular events that are underestimated by traditional risk stratification algorithms. We sought to determine clinical and echocardiographic predictors of adverse outcomes in CKD patients.

Methods

Stage 3 and 4 CKD patients without previous cardiac disease underwent a comprehensive transthoracic and stress echocardiogram, with left ventricular (LV) and left atrial (LA) strain analysis. Participants were followed for the primary end point of a composite of all-cause death and major adverse cardiovascular events (MACE). The secondary end point was a composite of cardiovascular death and MACE.

Results

243 patients (male 63%; mean age 59.2 ± 14.4 years) were followed for a median of 3.9 ± 2.7 years. 69 patients met the primary endpoint and 58 the secondary end point. Age (p < 0.01), history of diabetes mellitus (p < 0.01), indexed LV mass(LVMI) (p < 0.01), LV global longitudinal strain(GLS) (p < 0.01), indexed LA volume(LAVI) (p < 0.01), E/e’ ratio (p < 0.01) and LA strain (LAs) (p < 0.01) were independent predictors of death and MACE. On Cox proportional hazards regression analysis, LAs (p < 0.01) was the only independent predictor for the primary end point in a model accounting for age, diabetes mellitus, LVMI, LVGLS, E/e’ and LAVI. LAs remained an independent predictor for the secondary end point.

Conclusions

LAs is an independent predictor of death and MACE in CKD patients, in whom the predominant cardiac abnormality is diastolic impairment. LAs is a prognostic biomarker, reflecting alterations in diastolic function in CKD.

Abstract P1709 Figure. Kaplan Meier curve of LAs

1679 E/e predicts exercise capacity and adverse cardiovascular outcomes in patients with chronic kidney disease

Funding Acknowledgements

Nil

OnBehalf

NA

Background

Patients with chronic kidney disease(CKD) have reduced physical fitness that contributes to the disproportionately elevated risk of cardiovascular disease in this population. Our aim was to assess the association between E/e’ and exercise capacity in CKD patients and the prognostic role of E/e’.

Methods

Patients with Stage 3/4 CKD, without previous cardiac disease were prospectively recruited. Recruited patients underwent transthoracic echocardiogram and exercise stress echocardiogram with assessment of exercise E/e’. Patients were compared, one to one, to age, gender and risk factor matched controls and were followed annually for 5 years for cardiovascular death and major adverse cardiovascular events (MACE). Exercise capacity was assessed as metabolic equivalents (METs) with reduced exercise capacity defined as METS of ≤7. Raised exercise E/e’ was defined as exercise E/average e’ of >13.

Results

156 CKD patients (62.8 ± 10.6 yrs, male 62%) were compared to 156 matched controls. CKD patients had higher rates of anemia (p < 0.01), larger left ventricular indexed mass (p < 0.01), larger LAVI (p < 0.01) and higher resting (p < 0.01) and exercise E/e’ (p < 0.01). Overall, CKD patients achieved lower METs (p < 0.01) with exercise and a greater proportion of CKD patients had METs ≤7 (p < 0.01). Receiver operating curves (Figure1) showed exercise E/e’ (AUC 0.89, CI 0.84-0.95, p < 0.01) to be the strongest predictor of reduced exercise capacity in CKD patients. Exercise E/e’ of >13 was also associated with higher rates of cardiovascular death and MACE amongst CKD patients.

Conclusion

Exercise E/e’ is a strong predictor of exercise capacity amongst CKD patients, who commonly have reduced exercise capacity presumably consequent to diastolic dysfunction. Raised exercise E/e’ in CKD patients is predictor of cardiovascular death and MACE.

Abstract 1679 Figure.

P246 Exercise E/e refines diagnosis of diastolic impairment in patients with chronic kidney disease

Background

Diastolic dysfunction is common in chronic kidney disease (CKD) patients and is associated with reduced exercise capacity. The ratio of early diastolic mitral inflow velocity to early diastolic mitral annulus velocity (E/e’) correlates with invasively measured left ventricular pressures, both at rest and during exercise. The aim of our study was to evaluate the relationship of resting and exercise E/e’ to exercise capacity in patients with stage 3 and 4 CKD.

Methods

CKD patients were prospectively recruited. All patients were required to be in sinus rhythm, without previous cardiac disease and with normal LVEF. The E/e’ ratio was assessed at rest and patients were stratified into 3 groups based on conventional clinical classifications (normal: ≤8, indeterminate: 8-14, raised: >14). Patients then underwent a symptom limited exercise stress echocardiogram whereby patients with resting E/e’ <14 additionally had post exercise E/e’ measured. Exercise capacity was assessed as metabolic equivalents (METs). A raised exercise E/e’ was defined as exercise E/e’ of ≥13. Lastly, we grouped patients based on abnormalities of baseline and exercise E/e’ (resting E/e’<14 & exercise E/e’<13, resting E/e’<14 & exercise E/e ≥13, resting E/e’ ≥14) and the relationship to METs achieved was evaluated.

Results

The cohort consisted of 156 CKD patients (62.8 ± 10.6 yrs, male 62%). 85% had hypertension and 39% had diabetes mellitus. 52/156 (34%) CKD patients had resting E/e’ of ≥14. Of the 104/156 (66%) CKD patients with normal/indeterminate resting E/e’, 66/104(63%) had normal exercise E/e’ <13 whilst 38/104(37%) had exercise E/e’ ≥13. Patients with resting E/e" & raised exercise E/e’ ≥13 achieved significantly lower METs compared to CKD patients with resting E/e’ <14 & exercise E/e’ <13 (5.0 ± 2.2 vs 8.8 ± 2.5, p< 0.01). Of note, METs achieved in this group were comparable to that achieved by CKD patients with raised resting E/e’ ≥ 14 (5.0 ± 2.2 METs vs 5.3 ± 2.6 METs, p = 0.55).

Conclusion

In CKD patients with normal/indeterminate resting E/e’, there is utility in performing exercise E/e’, which was increased in 37% of patients. Raised exercise E/e’ is associated with poorer exercise capacity and is a potential tool to refine diastolic abnormalities in patients with CKD.

Group Total (n,%) METs Achieved Exercise Duration (minutes) Resting E/e’ ≤ 14 & Exercise E/e’ ≤ 13 66/156 (42%) 8.8 ± 2.5 8.4 ± 3.1 Resting E/e’ ≤ 14 & Exercise E/e’ ≥ 13 38/156 (24%) 5.0 ± 2.2 6.0 ± 3.1 Resting E/e’ ≥ 14 52/156 (34%) 5.3 ± 2.6 5.6 ± 2.2