Monday, December 2, 2013

Time to Move to the HEART Score

A couple posts ago I mentioned it was time for the TIMI Risk Score for UA/nSTEMI to go the way of the dodo for evaluation of chest pain in the Emergency Department.  It wasn't derived from an Emergency Department population, doesn't have great predictive skill in identifying very-low-risk patients, and includes nonsensical elements (did you take an aspirin within the last 7 days?).

Alternatively, we have the HEART score: History, ECG, Age, Risk factors, Troponin.  This was derived – like the Wells score – from the elements of clinical gestalt, and ought to at least make better intuitive sense than the occasionally frizzy outputs from multivariate logistic regression.  It was initially derived and refined retrospectively, and this represents the prospective validation study.  These authors prospectively enrolled 2,440 patients from 10 centers in the Netherlands and followed them for a primary endpoint of a major adverse cardiac event (AMI, PCI, CABG, death) for six weeks.  They also collected the variables of interest necessary to calculate TIMI and GRACE risk scores for comparison of c-statistic.

Obviously, I'm recommending the HEART score because it outperformed the others – the c-statistic for HEART was 0.83, 0.75 for TIMI, and 0.70 for GRACE.  Most importantly, for the Emergency Department, it was superior at the low-end of the spectrum.  For the 34% of the population that was TIMI 0-1, 23/811 (2.8%) had 6-week MACE.  14.0% had GRACE 0-60, and 10/335 (2.9%) had MACE.  For HEART, 36.4% were 0-3 and ultimately 15/870 (1.7%) had MACE.

Even though there are 2,400 patients in this study, there are few enough in each individual category that confidence intervals for each predictive bucket are still relatively wide.  Then, you can still have a HEART score in the "very low risk" 0-3 range with a troponin >3x the normal limit and an abnormal EKG – which is seemingly counterintuitive.  They also don't compare their rule to clinical judgment, so we can't measure the performance of the rule in actual decision-making.

A couple other studies have either prospectively or retrospectively validated these findings with reasonable consistency.  It isn't perfect – but it's better than TIMI or GRACE – and it's what I currently use to support my shared decision-making discussions at disposition of the appropriate chest pain cohort.

http://www.heartscore.nl/en/

"A prospective validation of the HEART score for chest pain patients at the emergency department"
http://www.ncbi.nlm.nih.gov/pubmed/23465250

8 comments:

  1. Interesting. From the linked presentation, 41% of patients had chest pain. I wonder if your "abnormal EKG" and "elevated troponin" patients are in the group without chest pain and more likely to have been falsely positive or old EKG findings.

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  2. One question I have is what is the optimal timing of follow up outpatient testing/cardiology eval in the low risk cohort? Any studies regarding this? What do you tell your patients and what have you and your cardiology colleagues decided is appropriate?

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    1. You are asking a question that has no "right" answer – and given the limitations of all our tests, which patients even need follow-up for cardiac functional or radiographic testing? There's no way to be "zero miss" without grossly over-testing. For insured folks I send home after doing this sort of ED risk-stratification, I tell them the best research we have gives them roughly X chance of having an event in the next six weeks. Since we don't have a specific protocol in place for expedited cardiac testing, I have to simply refer them back to PCP in 2-4 days to determine what, if any, further evaluation is necessary. Most everything ends up being individualized based on the circumstances and resources. As for optimal timing … I'm not familiar with that evidence ….

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  3. Agree about the TIMI but still kind of like the 2 hour TIMI http://www.ncbi.nlm.nih.gov/pubmed/23067909 from Martin Than. Would be nice to discard the ASA element and see the performance. Still don't understand why no one uses Calcium Scoring before committing people to stress testing. Many have scores of zero and can instantly go home...

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    1. I think my major problem with the various 2-hour studies published from New Zealand etc. by that group is they don't really classify very many patients from their cohorts into that "low risk" group. I suppose, if you're already admitting everyone, then even 15% extra discharges is significant. I prefer the results reported by HEART in the sense that you get some idea what the risks are as the score climbs – though, I'd like to see even more patients enrolled prospectively, and see if the LR ratios for the different categories are different.

      Re: calcium scoring – I think, again, when you're doing a "rule out" screening test that's not very specific, you end up over testing from false positives. It's definitely a challenge determining how to balance likelihood of CAD and test appropriateness with our general desire to prevent bad outcomes for every member of our patient population.

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  4. One big -- and usual -- problem here is the use of MACE, which includes PCI, which is a subjective call. And we all know some cardiologists who will just go ahead and cath the patient on revisit...

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    1. Yes – MACE, obviously, serve a lovely function allowing drug companies to decrease sample sizes and find differences in groups that might otherwise be imaginary. However, the components of MACE absolutely need to be narrow, non-subjective outcomes.

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    2. Seth, looks like most people who had MACE in the ADAPT and ASPECT studies had a subsequent NSTEMI (about 13%). only 1% cath rate.
      Ryan ...What about the Endpoints of HEART [no arrhythmias, blocks, shock]...if you add them up they al account for 1% of the 15% that have MACE in the ADAPT and ASPECT studies - could these have changed the game for HEART?

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