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Editorial
When is low-risk chest pain acceptable risk chest pain? Samantha J Brace-McDonnell,1,2 Simon Laing2 Undifferentiated chest pain is a presenting complaint facing the emergency medicine clinician with ever increasing frequency.1 Increasing public awareness regarding ischaemic heart disease has helped contribute towards understandable increasing concern. The net result is that patients hold a lower threshold to present to the emergency department (ED) for assessment. With these patients holding a lower pretest probability for acute coronary syndrome, the art of emergency medicine is being able to risk-stratify patients into those requiring admission for further assessment for a possible acute coronary syndrome and discharging home those patients whose likelihood of the disease is under the test threshold. Setting your threshold too high for investigation leads to unacceptable low pick up of cases and a missed opportunity to treat a disease with a significant morbidity and mortality; set your threshold too low for investigation and not only do you exposure patients to the elevated risk of false positives and unnecessary and potentially harmful treatment but you also increase the burden of over investigation upon an acute healthcare system already bursting at the seams. It is well documented that clinicians are not able to accurately estimate the pretest probability for acute coronary syndrome accurately, with a persistent overestimation of patients risk.2 Classical teaching regarding risk assessment for potential acute coronary syndrome and many current guidelines place the emphasis upon the importance of risk factors for ischaemic heart disease (IHD), which confer a chronic risk of developing the disease, but these have been inappropriately used for the assessment of acute coronary syndrome in the ED.3 4 Thrombolysis in Myocardial Infarction (TIMI) and Global Registry for Acute Coronary Events (GRACE) scoring for acute coronary syndrome are among the most frequently used in the UK. The GRACE score gives estimates for 6-month 1
Warwick Clinical Trials Unit, University of Warwick, Coventry, UK; 2Emergency Department, Heart of England NHS Trust, Birmingham, UK Correspondence to Samantha J Brace-McDonnell; [email protected]
1402
morbidity and mortality.5 Although useful, GRACE’s longer period of prognostication is too long to reflect the likely follow-up time for investigation following discharge from ED for IHD. TIMI risk calculation requires background information to be available; if the patient has had an angiogram, the clinician needs to ascertain whether there was >50% stenosis. This information may not always be readily available affecting the validity of the tool. The Manchester Acute Coronary Syndromes (MACS) trial, conducted by Body et al,6 derives and validates a new decision rule for suspected cardiac chest pain. They acknowledge that the current gold standard of investigation often necessitates a hospital admission to rule out the diagnosis of acute coronary syndrome and a cohort of false negatives. The study successfully demonstrates the ability to identify a significant cohort of patients who can be classified as ‘very low risk’, which was shown to infer a risk of 0.0% of AMIs within the next 30 days and a risk of missed acute coronary events (MACE) of 1.6% who may be deemed low enough risk for safe discharge.6 More than just identifying a dichotomous admit/discharge category, it enabled patients to be placed into one of several quantitative categories of risk for AMI/MACE. The factors incorporated into the MACS decision tool do hold benefits over the GRACE and TIMI scores as it prognosticates over a more appropriate time frame of 30 days and can be accurately evaluated by information not requiring previous patient investigations. Sadly this is not a risk stratification tool that is ready for the prime time just yet. One of the biomarkers, heart-type fatty acid binding protein will not be available in many UK biochemistry laboratories but may well be in years to come. The HEART score, as mentioned in this paper’s discussion, is a pre-existing risk stratification tool for chest pain that incorporates features from the history, ECG, past medical history and a serum troponin result.7 The obvious benefit to this tool being that it uses a biomarker that is readily available in hospitals already and could be implemented currently. Again this score splits patients into those at a low risk (
Editorial
When is low-risk chest pain acceptable risk chest pain? Samantha J Brace-McDonnell,1,2 Simon Laing2 Undifferentiated chest pain is a presenting complaint facing the emergency medicine clinician with ever increasing frequency.1 Increasing public awareness regarding ischaemic heart disease has helped contribute towards understandable increasing concern. The net result is that patients hold a lower threshold to present to the emergency department (ED) for assessment. With these patients holding a lower pretest probability for acute coronary syndrome, the art of emergency medicine is being able to risk-stratify patients into those requiring admission for further assessment for a possible acute coronary syndrome and discharging home those patients whose likelihood of the disease is under the test threshold. Setting your threshold too high for investigation leads to unacceptable low pick up of cases and a missed opportunity to treat a disease with a significant morbidity and mortality; set your threshold too low for investigation and not only do you exposure patients to the elevated risk of false positives and unnecessary and potentially harmful treatment but you also increase the burden of over investigation upon an acute healthcare system already bursting at the seams. It is well documented that clinicians are not able to accurately estimate the pretest probability for acute coronary syndrome accurately, with a persistent overestimation of patients risk.2 Classical teaching regarding risk assessment for potential acute coronary syndrome and many current guidelines place the emphasis upon the importance of risk factors for ischaemic heart disease (IHD), which confer a chronic risk of developing the disease, but these have been inappropriately used for the assessment of acute coronary syndrome in the ED.3 4 Thrombolysis in Myocardial Infarction (TIMI) and Global Registry for Acute Coronary Events (GRACE) scoring for acute coronary syndrome are among the most frequently used in the UK. The GRACE score gives estimates for 6-month 1
Warwick Clinical Trials Unit, University of Warwick, Coventry, UK; 2Emergency Department, Heart of England NHS Trust, Birmingham, UK Correspondence to Samantha J Brace-McDonnell; [email protected]
1402
morbidity and mortality.5 Although useful, GRACE’s longer period of prognostication is too long to reflect the likely follow-up time for investigation following discharge from ED for IHD. TIMI risk calculation requires background information to be available; if the patient has had an angiogram, the clinician needs to ascertain whether there was >50% stenosis. This information may not always be readily available affecting the validity of the tool. The Manchester Acute Coronary Syndromes (MACS) trial, conducted by Body et al,6 derives and validates a new decision rule for suspected cardiac chest pain. They acknowledge that the current gold standard of investigation often necessitates a hospital admission to rule out the diagnosis of acute coronary syndrome and a cohort of false negatives. The study successfully demonstrates the ability to identify a significant cohort of patients who can be classified as ‘very low risk’, which was shown to infer a risk of 0.0% of AMIs within the next 30 days and a risk of missed acute coronary events (MACE) of 1.6% who may be deemed low enough risk for safe discharge.6 More than just identifying a dichotomous admit/discharge category, it enabled patients to be placed into one of several quantitative categories of risk for AMI/MACE. The factors incorporated into the MACS decision tool do hold benefits over the GRACE and TIMI scores as it prognosticates over a more appropriate time frame of 30 days and can be accurately evaluated by information not requiring previous patient investigations. Sadly this is not a risk stratification tool that is ready for the prime time just yet. One of the biomarkers, heart-type fatty acid binding protein will not be available in many UK biochemistry laboratories but may well be in years to come. The HEART score, as mentioned in this paper’s discussion, is a pre-existing risk stratification tool for chest pain that incorporates features from the history, ECG, past medical history and a serum troponin result.7 The obvious benefit to this tool being that it uses a biomarker that is readily available in hospitals already and could be implemented currently. Again this score splits patients into those at a low risk (
![[Chest pain units or chest pain algorithm?].](/assets/img/hold.png)
