Utilizing APACHE IV Score to Predict Adverse Outcomes Among STEMI Patients

Norton, Jonathan

Background
Many patients with ST elevation myocardial infarction (STEMI) are admitted to the intensive care unit (ICU) after emergent percutaneous revascularization. However, a large portion of STEMI patients do not merit ICU admission due to their low acuity. We sought to examine whether, among post-STEMI patients admitted to the ICU at a large, regional health system, if a severity of illness scoring system, such as APACHE IV, could predict ICU length of stay (LOS) and mortality.

Methods
This was a retrospective study of STEMI patients admitted to the ICU at Christiana Hospital June 2017-June 2018, a 900-bed academic regional medical center in Delaware. Data was defined by the Action Registry and Cath-PCI databases. Acute Physiology and Chronic Health Evaluation APACHE III &IV scores were retrieved for all STEMI patients and were analyzed for complications, length of stay, and in-hospital mortality. Patients were stratified by APACHE score.

Results
Among 261 STEMI patients who received revascularization from June 2017-June 2018 timeframe the mean age was 62.8 years and the mean APACHE score was 40.2. The mean length of stay (LOS) from ICU admission until time of transfer order for patients with a low APACHE score (0-20) was 0.92 (SD:1.4) days compared to APACHE predicted 1.49 (SD: 0.45) days. Patients with intermediate scores (21-40) had a mean ICU LOS of 1.03 (SD:1.6) days compared to an APACHE predicted 1.63 (SD:0.5) days. Among the 173 patients with an APACHE score 40 or less there were no in-hospital deaths with a coincidingly low mean APACHE ICU mortality score of 0.01 and a mean APACHE hospital mortality score of 0.019. Assuming a per-patient day charge difference between the ICU and a non-ICU setting of $2,432 per patient-day, $384,426 could have been saved over one year if the patients with low APACHE scores had avoided the ICU.

Conclusions
We found that patients with low APACHE IV scores had a low likelihood of in-hospital death after STEMI. Patients with low APACHE scores can be safely admitted to a cardiac stepdown unit which would provide substantial savings to the institution. Further prospective studies are needed to confirm these findings.