P847Performance of the GRACE score in patients with type 1 and type 2 myocardial infarction

Introduction

The Global Registry of Acute Coronary Events (GRACE) score is a widely used risk stratification tool in the evaluation of patients with myocardial infarction. However, the performance of GRACE in patients with myocardial infarction secondary to oxygen supply-demand imbalance in the absence of atherothrombosis (type 2 myocardial infarction), is uncertain. Outcomes in patients with type 2 myocardial infarction are poor, and a risk stratification tool is urgently required.

Methods

We assessed the GRACE score in two cohorts of consecutive patients presenting to the Emergency Department with suspected acute coronary syndrome. One cohort was recruited as part of a stepped wedge cluster randomised controlled trial across ten hospitals in Scotland, and one cohort from a large tertiary centre in Sweden. All diagnoses were adjudicated according to the Fourth Universal Definition. We applied the GRACE 2.0 algorithm to estimate death at one year. We assessed model discrimination using the area under the receiver-operator-curve (AUC), and compared AUC between type 1 and type 2 myocardial infarction using the DeLong test. Calibration was assessed using the Hosmer-Lemeshow (HL) goodness of fit test.

Results

We identified 2,538 and 1,080 patients with type 1 myocardial infarction from the Scottish and Swedish cohorts, with death from any cause occurring in 378 (14.9%) and 112 (10.4%) patients, respectively. The AUC for the GRACE score was 0.843 (0.823–0.864) and 0.848 (0.810–0.886). There were 642 and 247 patients with type 2 myocardial infarction in the Scottish and Swedish cohorts, respectively, with death occurring in 144 (22.4%) and 57 (23.1%) patients. The AUC was 0.708 (0.662–0.754) and 0.733 (0.657–0.808), (P<0.001 for both compared to type 1 myocardial infarction). The results of the HL Test suggest that the calibration of the GRACE 2.0 score needs further improvement (Table).

Evaluation of GRACE 2.0 algorithm Type 1 Myocardial Infarction Type 2 Myocardial Infarction Scotland (n=2,538) Sweden (n=1,080) Scotland (n=642) Sweden (n=247) Deaths 378 (14.9%) 112 (10.4%) 144 (22.4%) 57 (23.0%) AUC (C-statistic) 0.843 (0.823–0.864) 0.848 (0.810–0.886) 0.708 (0.662–0.754) 0.733 (0.657–0.808) P-value for HL <0.001 <0.001 <0.001 <0.001 AUC: Area Under the receiver-operator Curve; HL: Hosmer-Lemeshow test.

Figure 1. ROC curves

Conclusions

The GRACE score provided excellent discrimination for all cause death at one year in two contemporary consecutive patient cohorts with tye 1 myocardial infarction. In patients with type 2 myocardial infarction, GRACE performed well, but recalibration or the development of novel risk scores has the potential to improve risk stratification.

P3593Improving the performance of high-sensitivity cardiac troponin for the diagnosis of myocardial infarction

Background

The Universal Definition of Myocardial Infarction (UDMI) mandates a rise and/or fall in high-sensitivity cardiac troponin (hs-cTn) concentration with at least one measure above the 99th centile of a healthy reference population. However, the 99th centile varies by age, sex, and prevalence of comorbid disease within reference populations, and the application of a single threshold may create diagnostic uncertainty in unselected patients attending the Emergency Department.

Purpose

To compare performance of hs-cTnI at the 99th centile with a model that includes additional clinical variables, for the diagnosis of type 1 myocardial infarction.

Methods

The High-Sensitivity Troponin in the Evaluation of patients with Acute Coronary Syndrome (High-STEACS trial) was a stepped wedge cluster randomised controlled trial of 48,282 consecutive patients across 10 hospitals in Scotland. We evaluated the positive predictive value (PPV) of a hs-cTnI >99th centile for a diagnosis of type 1 myocardial infarction. Patients with ST-segment elevation myocardial infarction (STEMI) were excluded, and all were adjudicated according to the 4th UDMI. The study population was randomly divided into derivation (80%) and internal validation (20%) cohorts. Using generalised additive modelling, we tested the effect of adding clinically relevant variables to hs-cTnI for the prediction of type 1 myocardial infarction in the derivation cohort, and assessed performance of the final model in the validation cohort.

Results

We included 47,101 consecutive patients (61±17 years, 47% female), of whom 9,057 (19%) had at least one hs-cTnI >99th centile (7,207 in derivation and 1,850 in validation cohorts). There were 4,087 (45%) patients with type 1 myocardial infarction, with 3239 (45%) and 848 (46%) in the derivation and validation cohorts, respectively. Across the study population, PPV for type 1 myocardial infarction reduced markedly with increasing age (Figure). Age, sex, chest pain, ischaemia on the electrocardiogram, creatinine and rate of change of hs-cTnI were included in the model. Comorbidities (ischaemic heart disease, diabetes, stroke and hyperlipidaemia) did not improve model performance. In the validation cohort, the area under the curve (AUC) for type 1 myocardial infarction using the 99th centile alone was 0.72 (95% CI 0.70–0.74), whereas the AUC for the optimised model was 0.84 (95% CI 0.82–0.85) (p<0.001 by DeLong's test for difference, see Figure).

Figure 1

Conclusion

The diagnostic performance of the 99th centile for type 1 myocardial infarction is poor, particularly in older populations. A simple model including readily available clinical features improves diagnostic performance and with further external validation could support more individualised treatment decisions.

Acknowledgement/Funding

British Heart Foundation

249High-sensitivity cardiac troponin and the universal definition of myocardial infarction: a randomised controlled trial

Background

The Universal Definition of Myocardial Infarction recommends the 99th centile diagnostic threshold using a high-sensitivity cardiac troponin (hs-cTn) assay and the classification of patients by the etiology of myocardial injury. Whether implementation of this definition improves risk stratification, treatment or outcomes is unknown.

Methods

In a stepped-wedge cluster randomized controlled trial, we implemented a high-sensitivity troponin assay and the recommendations of the Universal Definition in 48,282 consecutive patients with suspected acute coronary syndrome across ten hospitals. In a pre-specified secondary analysis, we compared the primary outcome of myocardial infarction or cardiovascular death, and secondary outcome of non-cardiovascular death at one year across diagnostic categories as per the Fourth Universal Definition. We applied competing risks methodology in all analyses, using a cumulative incidence function and determining the cause-specific hazard ratio (csHR) for competing outcomes.

Results

Cardiac troponin concentrations were elevated in 21.5% (10,360/48,282) of all trial participants. Implementation increased the diagnosis of type 1 myocardial infarction by 11% (510/4,471), type 2 myocardial infarction by 22% (205/916), acute myocardial injury by 36% (443/1,233) and chronic myocardial injury by 43% (389/898). The risk and rate of the primary outcome was highest in those with type 1 myocardial infarction, whereas the risk and rate of non-cardiovascular death was highest in those with acute myocardial injury (Table, Figure). Despite increases in anti-platelet therapy and coronary revascularization after implementation, the primary outcome was unchanged in patients with type 1 myocardial infarction (csHR 1.00, 95% CI 0.82 to 1.21), or in any other category.

Adjusted csHR for competing outcomes Myocardial infarction or cardiovascular death Non-cardiovascular death Adjusted csHR (95% CI) Adjusted csHR (95% CI) Type 1 myocardial infarction 5.64 (5.12 to 6.22) 0.83 (0.72 to 0.96) Type 2 myocardial infarction 3.50 (2.94 to 4.15) 1.72 (1.44 to 2.06) Acute myocardial injury 4.38 (3.80 to 5.05) 2.65 (2.33 to 3.00) Chronic myocardial injury 3.88 (3.31 to 4.55) 2.06 (1.77 to 2.40) Cox regression models adjusted for age, sex, diabetes, ischaemic heart disease, season, days since trial onset and site of recruitment (as a random effect).

Cumulative incidence and number at risk

Conclusions

Implementation of the recommendations of the Universal Definition identified patients with different risks of future cardiovascular and non-cardiovascular events, but did not improve outcomes. Greater understanding of the underlying mechanisms and effective strategies for the investigation and treatment of patients with myocardial injury and infarction are required if we are to improve outcomes.

Acknowledgement/Funding

British Heart Foundation

Methodology of Niyantrita Madhumeha Bharata Abhiyaan-2017, a Nationwide Multicentric Trial on the Effect of a Validated Culturally Acceptable Lifestyle Intervention for Primary Prevention of Diabetes: Part 2

Background

The rapidly increasing diabetes burden, reaching epidemic proportions despite decades of efforts, reflects our failure to translate the proven evidence for prevention of diabetes. Yoga, with its holistic approach, alters the habituated patterns of lifestyles and behaviour. Motivated by the accumulating evidence, the Government of India funded a large randomized controlled trial.

Aims and Objectives

The twin objectives were: (a) estimate the prevalence of prediabetes and diabetes through a parallel multisite stratified cluster sampling method and (b) implement NMB 2017 (niyantrita madhumeha bharata abhiyaan), a randomized control trial using yoga based lifestyle program.

Materials and Methods

Screening for Indian Diabetes Risk score(IDRS) was conducted in randomly selected clusters in all 7 zones (65 districts from 29 states/union territories) of India. This was followed by detailed assessments in those with known diabetes and high risk (≥60) on IDRS. Those who satisfied the selection criteria and consented were recruited for the two armed waitlisted randomized control trial. A validated remedial diabetesspecific integrated yoga lifestyle module was taught to the experimental arm by certified volunteers of Indian Yoga Association. Followup assessments were done after 3 months in both groups. In this article, we report the methodology of the trial.

Results

Response to door to door visits (n-240,968 adults >20yrs) in randomly selected urban and rural households for screening was 162,330; detailed assessments (A1c, lipid profile, BMI, stress, tobacco etc) were performed on 50,199 individuals. Of these 12466 (6531 yoga 5935 control) consented and for the RCT; 52% females, 48% males; 38% rural, 62% urban; BMI 21.1 ± 3.8; waist circumference 91.7 ± 11.9. A1c in diabetes subjects in yoga group was 7.63 ± 2.17 and 7.86 ± 2.13 in control group.

Conclusion

This unique methodology provides the evidence to implement a validated yoga life style module using yoga volunteers in all parts of the country which is an urgent need to prevent India from becoming the global capital for diabetes.

Rational truncation of aptamer for cross-species application to detect krait envenomation

In majority of snakebite cases, the snake responsible for the bite remains unidentified. The traditional snakebite diagnostics method relies upon clinical symptoms and blood coagulation assays that do not provide accurate diagnosis which is important for epidemiological as well as diagnostics point of view. On the other hand, high batch-to-batch variations in antibody performance limit its application for diagnostic assays. In recent years, nucleic acid aptamers have emerged as a strong chemical rival of antibodies due to several obvious advantages, including but not limited to in vitro generation, synthetic nature, ease of functionalization, high stability and adaptability to various diagnostic formats. In the current study, we have rationally truncated an aptamer developed for α-Toxin of Bungarus multicinctus and demonstrated its utility for the detection of venom of Bungarus caeruleus. The truncated aptamer α-Tox-T2 (26mer) is found to have greater affinity than its 40-mer parent counterpart α-Tox-FL. The truncated aptamers are characterized and compared with parent aptamer for their binding, selectivity, affinity, alteration in secondary structure and limit of detection. Altogether, our findings establish the cross-species application of a DNA aptamer generated for α-Toxin of Bungarus multicinctus (a snake found in Taiwan and China) for the reliable detection of venom of Bungarus caeruleus (a snake found in the Indian subcontinent).

Secondary lymphedema after head and neck cancer therapy: A review

Secondary head and neck lymphedema (SHNL) is a chronic condition affecting patients who have undergone treatment for head and neck cancers. It results from the disruption of normal lymphatic flow by surgery and/or radiation. The incidence of secondary head and neck lymphedema varies anywhere between 12 and 54% of all patients treated for head and neck cancer, but it is still commonly under-diagnosed in routine clinical practice. In spite of awareness of this condition, treatment has been difficult as definitive staging, diagnostic, and assessment tools are still under development. This review article is aimed at looking at the evidence, standards of management, and deficiencies in current literature related to SHNL to optimize management of these patients and improve their quality of life.