May 16th, 2016

Real-World Coronary CT Angiography Use is Associated with Increased Healthcare Utilization

By Daniel Cabrera, M.D.

Author: Jake Morris MD

techheart

 

This is a summary from Morris et al. Comparative Trends and Downstream Outcomes of Coronary CT Angiography and Cardiac Stress Testing in Emergency Department Patients with Chest Pain: An Administrative Claims Analysis. Academic Emergency Medicine.

Coronary computerized tomography angiography (CCTA) is a rapidly emerging technology for the evaluation of chest pain in the Emergency Department (ED).  Numerous large randomized trials (CT-STAT, ACRIN-PA, ROMICAT II, and CT-COMPARE) have demonstrated that CCTA is safe in the assessment of patients at low risk for ACS, and that it significantly speeds up their evaluation in already crowded ED’s.

But does this accelerated evaluation come at a cost?  It has been suggested that CCTA, while safe and fast, may lead to more downstream procedures and healthcare utilization.  Because CCTA is an anatomical study and not a functional one, what are providers supposed to do if they identify a coronary plaque in a patient with chest pain?  Is that plaque causing ACS?  Does more testing need to be performed because there are not clear guidelines on how to interpret CCTA results?

To assess how these questions are being answered in the real-world, we performed an administrative claims analysis utilizing a large national claims database (OptumLabs Data Warehouse).  We identified over two million ED patients from January 2006 to December 2013 who presented with a primary diagnosis of chest pain.  We established patients into cohorts based on whether they received CCTA, myocardial perfusion scan (MPS), stress echocardiography (SE), or treadmill exercise electrocardiogram (TMET) within 72 hours of their ED visit.  We assessed whether patients in each group subsequently underwent invasive coronary angiography (ICA), percutaneous coronary intervention (PCI), or coronary artery bypass grafting (CABG).  We further evaluated if they were hospitalized, had repeat imaging, or returned to the ED within 30 days.

 

Trends in Non-invasive Cardiac Testing:

  • During the study period, CCTA use increased from 0.8% to 4.5% of all cardiac testing within 72-hours, a change of 434% (P for trend < .001). At the same time, rates of other testing decreased (Figure 1).
  • Of all chest pain patients, 21.5% went on to have some form of non-invasive cardiac testing.
  • Of those receiving cardiac testing, 66% had MPS, 20% had SE, 11% had TMET, and 3% had CCTA.

Use of Downstream Resources

  • To compare cohorts, we used propensity-matching to control for coronary artery disease (CAD) risk factors, Charlson-Deyo comorbidity index, and baseline differences in age and sex.
  • After matching, there was no difference in the 30-day rate of AMI between testing modalities.
  • 8.3% of patients evaluated with CCTA subsequently had repeat cardiac testing.
  • Compared to MPS, CCTA was associated with higher rates of PCI (odds ratio [OR]=1.25, 95% confidence interval [CI] 1.04-1.51), and CABG (OR=1.47; 95% CI, 1.03-2.13) (Table 5).
  • Compared to stress echocardiography and treadmill stress testing, CCTA was associated with more invasive procedures, hospitalizations, return ED visits, and repeat noninvasive testing.

What’s the Bottom Line?

CCTA use increased four-fold during the study period and was associated with higher rates of PCI, CABG, repeat noninvasive testing, hospitalization, and return ED visits.  This suggests that real-world CCTA use comes at the cost of increased healthcare utilization, and highlights the need for clear guidelines on the use and interpretation of CCTA.

  

Figure 1. CCTA and functional cardiac stress testing use in Emergency Department patients with chest pain.

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Table 5. Associations between CCTA, downstream utilization and acute myocardial infarction after propensity-score matching.

  Propensity model 1 Propensity model 2 Propensity model 3
Outcome CCTA vs MPS CCTA vs SE CCTA vs TMET
  OR* 95% CI P-value OR* 95% CI P-value OR* 95% CI P-value
Procedures 0.80 0.72-0.88 <.0001 1.23 1.10-1.37 0.00 1.12 1.00-1.25 0.04
Cardiac Catheterization 0.79 0.72-0.87 <.0001 1.21 1.08-1.35 0.00 1.11 0.99-1.24 0.07
PCI 1.25 1.05-1.51 0.02 1.49 1.22-1.81 <.0001 1.27 1.05-1.53 0.01
CABG 1.47 1.03-2.13 0.04 1.36 0.96-1.95 0.09 1.31 0.92-1.87 0.13
Healthcare Utilization
Repeat ED Visit 0.95 0.85-1.07 0.43 1.20 1.06-1.36 0.00 1.09 0.97-1.24 0.15
Hospitalization 1.10 0.99-1.22 0.07 1.59 1.42-1.78 <.0001 1.26 1.13-1.40 <.0001
    Repeat Cardiac Testing 1.68 1.48-1.90 <.0001 3.16 2.72-3.68 <.0001 1.32 1.17-1.48 <.0001
Acute Myocardial infarction within 30 days 1.00 0.47-2.12 1.00 1.00 0.47-2.12 1.00 0.82 0.40-1.67 0.59

 

Image by Shutterstock used under permission

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