Elderly patients presenting to the ED frequently have troponin levels sent at triage. When we later see the patient we are often dismayed to find a slightly elevated level. Why might this happen? Well, any of the following can raise the troponin:

• Tachycardia


• Infection


• Ventricular hypertrophy


• Background ischaemic heart disease


• Heart valve disease


• CKD


• PE


• Chemotherapy

But could it be a heart attack?

On the one hand, it is true that in geriatrics, "atypical is typical" (Christian Nickel). We've known for some time that an elderly person can have an myocardial infarction (MI) without the typical symptom of chest pain. Data analysis of half a million patients on a national registry in the US^​[1]​ found that 33% did not report this symptom. The patients in this group were more likely to be elderly, female and to have diabetes or heart failure. Common symptoms included dyspnoea, fatigue, altered mental status and syncope.

On the other hand, it is likely that routine troponin testing rarely benefits patients. If the history doesn't fit with a possible MI, we find ourselves playing a game with numbers. Patients lose in this game, as they usually have to wait for repeat blood tests and sometimes end up with an unnecessary admission.

But what is the actual frequency of MI among elderly ED patients presenting with nonspecific complaints? What a great question! Today's paper is the first to try and answer it...

The paper

Wang AZ, Schaffer JT, Holt DB et al. Troponin testing and coronary syndrome in geriatric patients with nonspecific complaints: are we overtesting? Acad Emerg Med. 2020;27:6-14^​[2]​

Inclusions, exclusions
A retrospective study of patients aged >65 who presented to the ED of one large hospital over a 6-month period with nonspecific complaints. The following were designated to be 'nonspecific' complaints: weakness, dizziness, lethargy, medical problem, examination requested, failure to thrive, multiple complaints. In the UK this group would certainly include the classic "off legs" and "generally unwell". Each patient had to have a troponin level to be included in the study (of course). Two physicians, blinded to the troponin result, checked each case to ensure no specific or focal complaint was subsequently uncovered in the history.

Definition of ACS
ACS (acute coronary syndrome) was defined as any of the following:
1. A documented ST elevation MI
2. An angiogram showing complete occlusion or stenosis >70%
3. A stress test or echo consistent with inducible ischaemia
4. A troponin rise and fall in a pattern typical of ACS with no other obvious alternative cause

This was assessed by two other physicians, also blinded to the study hypothesis. Patients were followed up for 30 days, via the hospital records and those of the regional database to ensure no MIs were missed.

Results
Of the 412 patients in the final analysis, 82 (20%) had at least one elevated troponin. Five patients (1.2%) were determined to have had ACS within 30 days. No one developed ACS after being discharged from hospital.

This is a false positive rate of nearly 20%, and gives a risk of ACS of 1.2% in this group.

Limitations

• It's a descriptive study with no comparison group


• The definition of 'nonspecific complaint' is pretty subjective


• Troponin was sent at the discretion of the physician. This suggests that the 182 patients that didn't have a level sent were considered very low risk for ACS. Not including these cases probably led to an over-estimation of the risk. We'd have a more accurate idea if the policy had been to send troponins of every single patient


• Four of the five patients diagnosed with ACS only had troponin levels and non-stress echo - this falls short of definitively diagnosing an acute MI. In fact, the treating physicians of two of these patients felt they did not have an MI. Taking these two out reduces the risk to 0.7%


• The one patient with angiography-proven thrombus also had septic shock and severe hyperkalaemia - i.e. she wasn't someone that could have been discharged with a 'silent' MI

Comments

One may argue that no one wants to miss an MI, and even a rate of 1.2% justifies routine troponin testing in this population. However, there are potential harms associated with this approach. Time in hospital is associated with several adverse effects, including infection, deconditioning and delirium.

The bottom line

ACS is very rare in elderly patients presenting with nonspecific complaints, but elevated troponin is not. This study does not support routine testing in this group.

1. 
   
   
   

   Canto J, Shlipak M, Rogers W, Malmgren J, Frederick P, Lambrew C, et al. Prevalence, clinical characteristics, and mortality among patients with myocardial infarction presenting without chest pain. JAMA [Internet] 2000;283(24):3223–9. Available from: https://www.ncbi.nlm.nih.gov/pubmed/10866870

   
   
   
   


2. 
   
   
   

   Wang AZ, Schaffer JT, Holt DB, Morgan KL, Hunter BR. Troponin Testing and Coronary Syndrome in Geriatric Patients With Nonspecific Complaints: Are We Overtesting? Acad Emerg Med [Internet] 2019;6–14. Available from: http://dx.doi.org/10.1111/acem.13766