Niamh Kilcullen

The British Cardiac Society Working Group definition of myocardial infarction: implications for practice

Objective: To assess the impact on observed mortality of the British Cardiac Society (BCS) definition of myocardial infarction (MI) in 11 UK hospitals. Design: Prospective observational registry. Setting: 11 adjacent hospitals in the West Yorkshire region. Patients: 2484 patients with the acute coronary syndrome (ACS) were identified during a six month period (28 April to 28 October 2003). Demographic, clinical, and treatment variables were collected on all patients. Deaths were monitored through the Office of National Statistics. Patients were categorised into three groups according to the BCS definition of MI: ACS with unstable angina (UA), ACS with myocyte necrosis, and ACS with clinical MI. Results: 30 day mortality was 4.5%, 10.4%, and 12.9% (p < 0.001) in the ACS with UA, ACS with myocyte necrosis, and ACS with clinical MI groups, respectively. At six months the mortality for patients in the groups ACS with clinical MI and ACS with myocyte necrosis was similar (19.2% v 18.7%), being higher than for ACS with UA (8.6%). Same admission percutaneous coronary intervention was similar in groups with clinical MI and myocyte necrosis (11.1% v 10.7%, respectively) as was coronary artery bypass grafting (2.6% v 2.7%, respectively). However, these two groups differed significantly in the prescribing of secondary prevention (aspirin, 79% v 69%; statins, 80% v 68%; β blockers, 66% v 53%; and angiotensin converting enzyme inhibitors, 65% v 53%; p < 0.001). Conclusions: At 30 days the new BCS categories for MI predict three distinct outcomes. However, within a contemporary UK population this was no longer apparent at six months, as mortality for patients with ACS with myocyte necrosis had risen to the same level as those for patients with ACS with clinical MI. One possible explanation for this is the apparent under use of drugs known to improve prognosis after traditionally defined MI.

Diabetes Mellitus and Mortality after Acute Coronary Syndrome as a First or Recurrent Cardiovascular Event

Background Diabetes Mellitus (DM) is associated with adverse cardiovascular prognosis. However, the risk associated with DM may vary between individuals according to their overall cardiovascular risk burden. Therefore, we aimed to determine whether DM is associated with poor outcome in patients presenting with Acute Coronary Syndrome (ACS) according to the index episode being a first or recurrent cardiovascular event. Methods and Findings We conducted a retrospective analysis of a prospective cohort study involving 2499 consecutively admitted patients with confirmed ACS in 11 UK hospitals during 2003. Usual care was provided for all participants. Demographic factors, co-morbidity and treatment (during admission and at discharge) factors were recorded. The primary outcome was all cause mortality (median 2 year follow up), compared for cohorts with and without DM according to their prior cardiovascular disease (CVD) disease status. Adjusted analyses were performed with Cox proportional hazards regression analysis. Within the entire cohort, DM was associated with an unadjusted 45% increase in mortality. However, in patients free of a history of CVD, mortality of those with and without DM was similar (18.8% and 19.7% respectively; p = 0.74). In the group with CVD, mortality of patients with DM was significantly higher than those without DM (46.7% and 33.2% respectively; p<0.001). The age and sex adjusted interaction between DM and CVD in predicting mortality was highly significant (p = 0.002) and persisted after accounting for comorbidities and treatment factors (p = 0.006). Of patients free of CVD, DM was associated with smaller elevation of Troponin I (p<0.001). However in patients with pre-existing CVD Troponin I was similar (p = 0.992). Conclusions DM is only associated with worse outcome after ACS in patients with a pre-existing history of CVD. Differences in the severity of myocyte necrosis may account for this. Further investigation is required, though our findings suggest that aggressive primary prevention of CVD in patients with DM may have beneficially modified their first presentation with (and mortality after) ACS.

Arrhythmic acute coronary syndrome and anomalous left main stem artery: culprit or innocent bystander

A 76-year-old man was admitted with sudden onset chest pain, palpitations and collapse. His ECG showed ventricular tachycardia (Figure 1a) and subsequent troponin was mildly elevated. Coronary angiography appeared to show an anomalous left main stem coronary artery arising from a position near the right coronary sinus (Figure 1b). The vessel is seen to run posterior to a second catheter which has been placed in the right ventricular outflow tract (Figure 1d, black arrow), suggesting an interarterial course. However, it was not possible to identify an acutely ruptured coronary plaque. It was thus unclear whether the troponin rise related to the tachycardia or was the result of genuine infarction.

Dilated cardiomyopathy as the first presentation of coeliac disease: association or causation?

Global ventricular impairment is a frequent presentation in clinical practice, but dissection of causative mechanisms from clinical associations is challenging. We present the case of a 19-year-old man who presented with dilated cardiomyopathy as the first presentation of coeliac disease. The manifestation of iron deficiency anaemia prompted gastroenterology input and enabled accurate diagnosis. It is unclear whether coeliac disease was simply coexistent or directly implicated in pathophysiology. Mechanisms may relate to nutritional deficiencies or autoimmune myocarditis arising from cross-reactivity. We advocate early multidisciplinary involvement in such contexts to aid with management strategy. Despite adherence to a gluten-free diet, ventricular dysfunction persisted and he has been referred to a cardiac transplant centre.

7 In acute coronary syndromes, heart-type fatty acid binding protein is a more accurate predictor of long term prognosis than troponin

Introduction We have previously shown that heart-type fatty acid binding protein (H-FABP) has a role in predicting all-cause mortality after acute coronary syndromes (ACS) and after multivariable analysis, provides additional information to that gained from the GRACE clinical risk factor score, troponin and highly sensitive CRP. H-FABP is released into the circulation during myocardial ischaemia and after myocardial necrosis, in contrast to troponin which is released after myocardial necrosis only. We have also shown that there is a group of ACS patients who are at high risk of cardiac events and death despite normal troponin levels on admission. This group may benefit from an early invasive strategy. Hypothesis Plasma H-FABP level, taken between 12 and 24 h after admission, can identify troponin negative ACS patients who are at a high long term risk of death. Methods Six-year mortality data is now available for patients enrolled in the FAB 1 study, for which 1-year mortality data was published in 2007. In this study, 1448 unselected patients admitted to hospital with ACS had serum H-FABP level measured in addition to usual care. Mortality was tracked by the UK Office of National Statistics. Results At 6 years overall all-cause mortality, available for 1421 patients (98.1%), was 43.5%. If troponin −ve/H-FABP −ve mortality was 20.9%; troponin −ve/H-FABP +ve 56.4%; troponin +ve/H-FABP −ve 20.2%; troponin +ve/H-FABP +ve 49.1%. Mortality rate was independent of troponin status but strongly related to H-FABP status. Conclusion The current system of stratification of ACS patients for early invasive management if troponin positive will miss a cohort of patients who are at high risk of death despite being troponin negative, and who may benefit from invasive investigation. Conversely, it is likely that some ACS patients undergo angiography based on a false positive troponin level. The addition of H-FABP measurement to the management of ACS could avoid this.Abstract 7 Figure 1

6 Cardiac morbidity and mortality can be accurately predicted in patients presenting with ACS using multiple biomarkers measured on an admission blood sample

Background Rapid assessment of patients with suspected acute coronary syndrome (ACS) allows the right patients to receive the right treatment at the right time. Discrimination of risk permits clinical triage into pathways of immediate inpatient or deferred outpatient care. It is known that a significant proportion of the ACS patients sent home following an “MI screen”, based on a negative 12-h troponin level, are misdiagnosed as having non-cardiac chest pain when in fact they are at high risk of cardiac events. It has been shown that the novel biomarker H-FABP can detect myocardial ischaemia even in the absence of myocyte necrosis. We hypothesise that a multi biomarker blood test incorporating troponin I, CK-MB and H-FABP, taken on admission, can accurately discriminate those patients with a non-cardiac cause of chest pain who are at low risk of cardiac morbidity or mortality. Methods We studied 519 patients with suspected ACS admitted to a single UK Teaching Hospital. A risk scoring model was constructed based on tertile values for Randox Cardiac-Array measurement of troponin I, H-FABP and CK-MB. These were measured on a blood sample taken at the time of hospital admission. The lowest two lower tertiles were each given a score of 1 and the top tertile a score of 3. The scores were then combined by summation resulting in an overall score of between 3 and 9. Outcome measures up to 12 months were: (i) death from all causes; (ii) repeat acute coronary syndrome (ACS) (iii); readmission for heart failure; (iv) readmission for cerebrovascular event (CVA); (v) coronary revascularisation. Results The distribution of Cardio-Array scores was: 3 (n=164; 31.6%); 5 (n=134; 25.8%); 7 (n=110; 21.2%); 9 (n=111; 21.4%). The cumulative incidence of events according to the Cardiac-Array score is shown in Abstract 6 table 1.Abstract 6 Table 1 The cumulative incidence of events according to the Cardiac-Array Score Score Death or ACS or HF or CVA or Revasc 3 0.61% 3.07% 3.11% 3.11% 4.28% 5 3.21% 5.77% 5.81% 5.81% 6.41% 7 11.11% 17.78% 19.05% 20.93% 24.44% 9 12.98% 16.23% 18.37% 18.92% 22.08% Ratio (9/3) 21.28 5.29 5.91 6.08 5.16 p Value <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 Conclusion Patients presenting with possible ACS who have a Cardiac-Array biomarker score of 3 or 5, as measured on their admission blood sample, have a very low rate of cardiovascular events. This tool could be used to safely triage patients towards early discharge and outpatient care, based upon available resources. A score of 7 or 9 would merit admission to hospital, and consideration of early cardiac catheterisation.