HEART Outcomes in the “Real World”

There are two parallel universes in medicine – the “real world”, where most physicians practice, and the “academic world”, where most research is performed. Then, these disparate universes are scattered across the physical world, with its rich tapestry of cultures, further complicating the generalizability of any one set of observations.

This example demonstrates this effect on outcomes from the HEART Score, typically applied for its utility in disposition of those with Low (0-3) scores. Scores in this range have been generally observed to have a 6 week rate of Major Adverse Cardiac Events in the 0.7 to 1.7% range. However, these outcomes are subject to those aforementioned limitations – mostly academic centers, frequently across the pond.

These results are from a prospective evaluation of practices and outcomes regarding the approach to chest pain in the Emergency Department, ongoing at Kaiser Permanente Southern California. In this study, clinicians have been routinely recording the HEART Score in the context of chest pain evaluation since May 2016, allowing for the abstraction of this score in structured data. This analysis captured all Kaiser members evaluated in the ED who were not diagnosed with an acute myocardial infarction at the index visit, and gathered outcomes from their data warehouse.

Based on 29,196 ED encounters, 59% were “low risk”, and most of the remainder were “intermediate risk” (4-6). The overall rate of 6 week MACE was only 0.4% in the low risk group and 2.4% for intermediate risk, with most MACE being driven by revascularization. Only 0.2% of low risk and 1.0% of intermediate risk suffered death or acute myocardial infarction within 30-days. These authors then go on to suggest a HEART Score of 5 should rather be considered the cut-off for safe discharge from the ED, the maximum at which 30-day death or AMI was ~1% , which would represent ~89% of ED visits.

These data may represent our best insight yet into the pragmatic application of HEART in U.S. EDs, where certain semi-subjective aspects or misinterpretation of score elements serve to skew the scores higher.  Rather than 0-3 representing a low-risk cohort, it is probably more likely 0-5 as these authors report.  This ties into our general risk-averse nature, which tends to result in virtually universal over-triage of most complaints in the ED, as our other over-testing trends would indicate.  These data also probably serve as a lesson to those who promote the application of other decision instruments in the ED, as we’ve recently seen with the Canadian Head CT Rule for minimal risk head injury, or potential indication creep from the Ottawa Subarachnoid Rule – we must exercise caution regarding downstream unintended consequences and low-value care as a result.

“The HEART Score for Suspected Acute Coronary Syndrome in U.S. Emergency Departments”
https://www.ncbi.nlm.nih.gov/pubmed/30286933