Clinician referrals for stress echocardiography: are we compliant with the NICE guidelines?

Accurate diagnosis of stable angina is of paramount importance, and where possible, this should be based on clinical history. In cases of uncertainty, the National Institute for Health and Care Excellence (NICE) provides a framework for assisting diagnosis based on pre-test likelihood (PTL) of coronary artery disease. Functional testing such as stress echocardiography (SE) is recommended as a first-line investigation in patients with PTL of 30-60%. This study evaluated hospital clinicians' adherence to this recommendation. A prospective analysis of patients referred for SE at a district general hospital between March and May 2013 was performed. Data were extracted from an electronic database of SE reports and medical notes. A total of 193 patients were assessed. The most common PTL was 61-90%, accounting for 40% of the cohort. Of them, 14% had a PTL of 30-60%. Of these, 15% had positive SE; 57% described non-anginal pain, as defined by NICE, of whom only nine cases had SE positivity. None of these patients required revascularisation. Findings suggest that SE is being used in a much broader selection group than advocated by NICE. This may often be for its exclusion value rather than to stratify risk. Although utility may be justified in high-risk patients to avoid proceeding directly to invasive angiography, SE appears to add little in those with non-anginal pain and with low PTL. Greater focus should be directed towards characterisation of symptoms, which may negate the need for subsequent investigation.

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%; beta 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.

External validation, extension and recalibration of Braunwald's simple risk index in a community-based cohort of patients with both STEMI and NSTEMI.

BACKGROUND: Using the simple risk index (SRI) that is based on age, heart rate and systolic blood pressure, we sought to evaluate the ability to predict outcome in AMI patients in a community-based population. METHODS AND RESULTS: We identified and evaluated 3684 consecutive patients with an admission diagnosis of possible AMI, who attended between 1st September and 30th November 1995. Two thousand one hundred fifty three patients had confirmed evidence of WHO definition AMI, of whom 1656 survived to hospital discharge. We evaluated the ability of the SRI to predict mortality over 30 days using the score generated by the equation (heart ratex[age/10]2)/systolic blood pressure. The SRI was a strong (c-statistic = 0.77 CI 0.74-0.79) predictor of 30-day mortality in both STEMI and all consecutive cases of WHO definition AMI. However, the model showed poor calibration when used on a community-based population with 30-day mortality being underestimated across all risk quintiles. Consequently we sought to recalibrate the quantitative aspects of the model for the total AMI population in the following way (Risk Index; 30-day mortality) (< or = 29.2; 9.2%), (29.3-37.8; 23.9%), (37.9-47.3; 34.6%), (47.4-61.5; 40.3%), (> or = 61.6; 65.5%). CONCLUSION: We have externally validated the SRI in an unselected cohort of consecutive WHO definition AMI patients. However, the original model consistently underestimated the likelihood of death at 30 days regardless of the calculated risk score. We have therefore suggested corrections to the risk estimates, to allow its application in an unselected community cohort.