Prognostic Value of CT Angiography in Patients With Inconclusive Functional Stress Tests

OBJECTIVES: We attempted to determine the prognostic value of coronary computed tomographic angiography (CTA) in patients with inconclusive functional stress tests. Patients with suspected coronary artery disease (CAD) and inconclusive noninvasive cardiac stress tests represent a frequent management challenge.

METHODS: We examined 529 consecutive patients with suspected CAD and prior inconclusive functional stress tests. All patients under went a coronary CTA scan using a 64-slice multidetector row scanner.CAD severity by coronary CTA was categorized as: 1) no evidenceof CAD; 2) nonobstructive coronary plaques (<30%); 3) mildstenosis (30% to 49%); 4) moderate stenosis (50% to 69%); and 5) severe stenosis (≥70%). Patients were also categorized according to a modified Duke prognostic CAD index. Survival analyses were performed using Cox proportional hazards models adjusted for baseline risk factors and coronary artery calcium score. The primary outcome of the study was the combined endpoint of all-cause mortality and nonfatal myocardial infarction.

RESULTS: Among patients with inconclusive stress tests, the large majority(69%) did not demonstrate significant CAD by coronary CTA. During a mean follow-up of 30.1 ± 11.1 months, there were 20(3.8%) deaths and 17 (3.2%) nonfatal myocardial infarctions. Multivariable Cox regression analysis revealed that the presence of increasing degrees of obstructive CAD by CTA was an independent predictor of adverse events (hazard ratio [HR]: 1.66 [95% confidence interval (CI): 1.23 to 2.23], p = 0.001). Indeed, the presence of ≥50% coronary stenosis was associated with an increased riskof events (HR: 3.15 [95% CI: 1.26 to 7.89], p = 0.01). Likewise,the Duke prognostic CAD index was also found to be an independent predictor of events (HR: 1.54 [95% CI: 1.20 to 1.97], p = 0.001).

CONCLUSIONS: Among patients with inconclusive functional stress tests, the noninvasive assessment of CAD severity by coronary CTA has been shown to provide incremental prognostic information beyond the evaluation of traditional risk factors and coronary artery calcium score. 

PMID:

Posted in Computed Tomography and tagged , , .

4 Comments

  1. See also:

    Prognostic value of cardiac computed tomography angiography: a systematic review and meta-analysis.
    Hulten EA, Carbonaro S, Petrillo SP, Mitchell JD, Villines TC.
    J Am Coll Cardiol. 2011 Mar 8;57(10):1237-47.
    PMID:

  2. In my opinion, this is a type of study that was required to have in our literature. We can argue that there is nothing new here or at least no unexpected great discoveries. Nonetheless, this is important data to have.

    What is interesting now is what do we do with it? If the 529 patients with prior inconclusive stress testing that had a CTA would have never had a stress test and would have only had a CTA, how would their risk-stratification and management have changed? Would it have changed at all?

  3. Has anyone ever had a patient have a CTA that required a stress test afterwards for further risk-stratification?

    I can’t recall having one.

  4. Jacobo,

    I think that is a relatively frequent pattern. A patient has a CTA with indeterminate, densely calcified (but not proximal) lesions.
    A stress evaluation would be the next step, unless the clinical presentation would suggest a high suspicion and the need for catheterization.

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