Background:
Chest pain accounts for 2-5% of all Emergency Room (ER) visits. Tools like TIMI score and HEART score exist to risk stratify patients, but a low threshold for admission has been traditional because the risk of inadvertent discharge of patients with true ACS. In this study, we evaluate the yield of myocardial perfusion scan (MPS) and diagnostic cardiac catheterization (cardiac-cath) in patients with low and intermediate pretest probability of ACS by TIMI score. We also evaluate the costs associated with these tests.
Methods:
We reviewed 120 patients admitted with chest pain between January 2015 and June 2016. Patients between the ages of 35-55 with low TIMI score (<=2) presenting with both typical and atypical chest pain were included. Anyone with a history of coronary artery disease (CAD) were excluded regardless of the TIMI score. Patients were categorized into three groups: 1) discharged with no further studies, 2) had MPS, or 3) underwent cardiac-cath based on positive MPS or high pretest probability. We then evaluated what portion of these patients had a positive stress test or CAD on cardiac-cath and the cost of these workups.
Results:
All patients had EKG and serial cardiac enzymes on admission. Out of the 120 patients, 11 were discharged without further testing after normal EKG and negative cardiac enzymes, 105 patients had MPS, and 4 underwent cardiac-cath without MPS. Out of the 105 patients undergoing MPS, 100 patients had negative MPS and were subsequently discharged. 1 patient had negative MPS but underwent coronary angiography due to developing NSTEMI after MPS. 4 out of 105 had positive MPS who subsequently had coronary angiography done. Out of these five patients undergoing cardiac-cath after MPS, no one had clinically significant CAD. Finally, of the four patients who underwent coronary angiography without MPS, 1 was found to have chronic occlusion of the RCA, which was managed medically without intervention while the remaining patients had no significant CAD. Typical or atypical chest pain did not affect the outcomes of the tests.
Conclusions:
Of the 120 patients evaluated, 109 patients (90.8%) underwent further imaging study. Only one had CAD on angiography, which was managed medically. The average length of stay for patients who were discharged without receiving further study was 1.22 days compared to 1.44 days for patients undergoing only MPS and 2.18 days for patients receiving cardiac-cath. The average cost of admission for patients who were discharged without intervention was $8305 compared to $13545 for patients receiving MPS and $23493 for patients receiving cardiac-cath. The hospital charge for MPS was $4620, which was 34% of the total cost of the admission for patients receiving the test. Total cost of admission for all three groups combined was $1627703. Our study shows that MPS and diagnostic catheterization in younger patients with low TIMI scores is of low yield diagnostically and significantly increases costs. Performing these tests in these patients does not appear to provide high value care.