!!Attention!! Next RM Online Course ~ Stroke 1 - Due February 29
Risk Management Communiqué
Prepared by Pete Steckl, MD, FACEP, Risk Management Director
January, 2012
Cardiac Risk Factor Analysis in the Evaluation of Chest Pain in the ED
Despite ongoing technological advances in cardiac evaluation and therapy, disposition of the ED chest pain patient remains an ongoing challenge. At 3 million ED visits per year, the sheer volume of these patients coupled with the potentially severe consequences of a misdiagnosis make chest pain assessment the most costly high risk area in emergency medicine practice.
I have a tendency to harp on about chest pain and its evaluation/risk in the ED. However, my concern is not without indication. For starters, it is important to realize that, all things being equal, 30% of all major emergency medicine lawsuits involve chest pain. The key word here is major. Though origins of lawsuits may vary, the average missed MI case tends to run in the hundreds of thousands of dollars in indemnity and, in the case of catastrophic outcome in an afflicted young, productive individual, a payout can easily rise to the millions of dollars.
Though there exist a multitude of diagnostic aids available in the evaluation and risk stratification of the atypical (as distinct from obviously non cardiac) chest pain patient with the normal ECG and negative initial set of cardiac enzymes, most cases require a period of observation which may often require admission. In these patients we are called upon to make a disposition decision based mainly on clinical history and physical exam findings. One of the accessory historical tools frequently relied upon by ED physicians to risk stratify real time is the set of classic cardiac risk factors for cardiac disease we have all been taught since medical school. The logic goes that increasing numbers of cardiac risk factors indicate a greater potential for cardiac ischemia. The accepted natural corollary would seem to be then that the less the numbers of risk factors, the less the likelihood of presence of ACS and finally, the absence of risk factors should make the patient at much decreased risk and might be a reliable deciding determinant of disposition home in a case of equivocal chest pain symptoms. Is this a valid, safe, and evidence based assumption? A review of a recent article on the subject would argue to the contrary.
First to review. The presence of the classic risk factors of smoking history, hypertension, hypercholesterolemia, diabetes, and coronary disease at a young age in a first-degree family member does indeed statistically have an impact on mortality. The well known and frequently cited Framingham heart study found that participants with two or more cardiac risk factors had a much higher risk of death compared with patients with zero or one factor. However, what is frequently overlooked is that the large and statistically significant sample of subjects of this study consisted exclusively of patients living in the community who were asymptomatic. This study, by definition cannot be generalized to the mainly symptomatic clientele presenting in the ED environment.
So of what use are cardiac risk factors in deciding symptomatic patient disposition from the ED, if at all? A retrospective study of 11,000 patients with possible ACS presenting to 8 U.S. ED’s published in the Annals of Emergency Medicine in February 2007 found that usefulness of these factors in predicting ACS was variable based on age. In this paper patients evaluated were divided into 3 age groups: those less than 40 years of age, those between 40-65, and those over 65. In the youngest age group, those patients presenting with chest pain who had a normal ECG and no risk factors had a rate of presence of ACS of just 0.3% and a negative likelihood ratio of 0.17 (0.1 or below indicates a virtual rule out of disease). However, the addition of just one risk factor to this group doubled the negative likelihood ratio to 0.36(thereby rendering it of minimal use in decision making). Not surprisingly, as age increased, the discriminatory utility of the absence of risk factors decreased and absence of risk factors in the setting of chest pain and a normal ECG in the 40-65 and > 65 age groups produced relatively dismal negative likelihood ratios of 0.53 and 0.96 respectively (of no use in clinical decision making).
On the plus side, increasing numbers of risk factors in all age groups did indeed increase positive likelihood ratios in a predictable fashion, albeit less so in the >65 year old age group, reflective of the fact that older age is a powerful risk for ACS in and of itself. Nevertheless, this study indicates that presence of a large risk factor burden is a reasonable factoid to include in presentation to support admission.
Aside from the concerning statistics above, a couple more sobering facts on risk factors to consider before sending out that “ low risk” chest pain patient with equivocal symptoms:
- More than ½ half of all patients with coronary artery disease have no established risk factors for cardiac disease.
- In the study above, of those patients determined to have ACS, one of every eight patients had no cardiac risk factors and just over 25% had only one cardiac risk factor.
In sum, cardiac risk factors, as described in the Framingham study, are of most use in the Family Practice setting in assessment of long-term risk and guiding patients in lifestyle modifications to decrease the potential for development of coronary artery disease. They are of much less value to us in our ED assessment of acute chest pain. The business of evaluating and risk stratifying negative workup chest pain depends greatly on careful history taking and continues to be one of the more hazardous duties with which we are charged. Presence of classic risk factors continues to be a valid indication for and a helpful aid in getting patients admitted for appropriate testing. However a cavalier utilization of absence of risk factors as a sole indicator for discharge in a patient clinically at risk for ACS is a strategy that is embarked upon only at great peril.
"This statement is for informational purposes only. Nothing contained herein should be construed to state a "standard of care”. We recognize that each patient encounter is unique with variable circumstances requiring independent physician discretion and judgment." |
