Table 2.
Model Parameters: Clinical Probabilities and Costs for the Decision Tree
| Variable Name | Baseline Value |
Range | Distribution | Data Origin or References |
|---|---|---|---|---|
| ACS Prevalence | 0.07 | 0–0.2 | Normal | Patient data |
| CCT Sensitivity | 1 | 0.85 1 |
Normal | Patient data,19,20, |
| CCT Specificity | 0.88 | 0.65 0.9 |
Normal | Patient data,19,20, |
| Stress test sensitivity (weighted mean) | 0.85 | 0.77–0.94 | ||
| - Nuclear SPECT | 0.86 | 0.81–0.96 | Normal | 12 |
| - Echocardiogram | 0.80 | 0.72–0.88 | 11 | |
| Stress test specificity (weighted mean) | 0.76 | 0.68–0.83 | ||
| - Nuclear SPECT | 0.74 | 0.67–0.91 | Normal | 12 |
| - Echocardiogram | 0.86 | 0.77–0.95 | 11 | |
| Hospital admission and cardiac catheterization | 0.07 | 0–0.2 | Normal | Patient Data |
| Probabilities | ||||
| SOC arm cardiac stress testing | 0.77 | |||
| - Nuclear SPECT | 0.67 | - | - | Patient data |
| - Echocardiography | 0.10 | - | ||
| MI or unstable in ED (SOC arm only) | ||||
| - Patients with ACS | 0.05 | 0–0.3 | Beta | Patient data |
| - Patients without ACS | 0.02 | 0–0.3 | ||
| No SOC cardiac stress testing or catheterization | 0.18 | - - |
- | Patient data |
| Incidental, non-cardiac findings on SOC imaging requiring further evaluation | 0 | 0.0008–0.01 | Beta | 21 |
| MI or death before diagnosis | ||||
| - CCT Arm | 0 | 0–0.5 | Beta | Patient Data,22 |
| - SOC arm | 0.01 | 0–0.5 | ||
| Cardiac re-evaluation for recurrent symptoms | 0.07 | 0–0.5 | Beta | Patient data |
| CCT contrast complication | 0 | 0.001–0.2 | Beta | Patient data,23 |
| CCT non-cardiac finding | ||||
| - CT non-cardiac findings requiring repeat CT | 0.04 | 0.04–0.09 | Beta | Patient data,13 |
| - Positive repeat CT requiring PET | 0.01 | 0–0.05 | ||
| Costs ($USD) | ||||
| Base case cost for SOC arm | $1,734 | $1,672– $1,877 | Normal | Patient data |
| Base case cost for CCT arm | $1,347 | $1,077–$1,616 | Normal | Patient data |
| Hospital admission and cardiac catheterization | $5,524 | $4,420, $6,629 | Normal | Patient data |
| Cardiac catheterization | $2,773 | $2,218–$3,327 | Normal | Patient data |
| Iodinated contrast complication | $897 | $0–$76,317 | Log normal | 17 |
| Incidental, non-cardiac CCT findings requiring repeat CT | $448 | $358–$538 | Normal | Patient data |
| - Positive repeat CT requiring further evaluation | $1,255 | $1,004–$2,644 | ||
| Cardiac re-evaluation for recurrent symptoms | $3,029 | $2,474–$6,629 | Normal | Patient data |
| MI or death before ACS diagnosis | $37,147 | $7,776–$117,490 | Normal | 6, 24 |
Costs were based on or adjusted to 2007 Medicare-based reimbursement amounts except for cardiac imaging costs which were based on 2010 Medicare reimbursements. Baseline costs were derived from patient data when available. The patient and literature data provided the range of values used for sensitivity and probabilistic Monte Carlo analyses. All costs were in US dollars ($).
ACS = acute coronary syndrome; CT = computed tomography; CCT = cardiac computed tomography; ED = Emergency Department; MI = myocardial infarction, SOC = standard of care, SPECT = single photon emission computed tomography.