Integrated SPECT/CT for Assessment of Haemodynamically Significant Coronary Artery Lesions in Patients With Acute Coronary Syndrome

OBJECTIVES: Early risk stratification in patients with non-ST elevation acute coronary syndromes (NSTE-ACS) is important since the benefit from more aggressive and costly treatment strategies is proportional to the risk of adverse clinical events. In the present study we assessed whether hybrid single photon emission computed tomography (SPECT)/coronary computed tomography angiography (CCTA) technology could be an appropriate tool in stratifying patients with NSTE-ACS.

METHODS: SPECT/CCTA was performed in 90 consecutive patients with NSTE-ACS. The Thrombolysis in Myocardial Infarction risk score (TIMI-RS) was used to classify patients as low- or high-risk. Imaging was performed using SPECT/CCTA to identify haemodynamically significant lesions defined as >50% stenosis on CCTA with a reversible perfusion defect on SPECT in the corresponding territory.

RESULTS: CCTA demonstrated at least one lesion with >50% stenosis in 35 of 40 high-risk patients (87%) as compared to 14 of 50 low-risk patients (35%; TIMI-RS <3; p <0.0001). Of the 40 high-risk and 50 (16%) low-risk TIMI-RS patients, 16 (40%) and 8 (16%), respectively, had haemodynamically significant lesions (p = 0.01). Patients defined as high-risk by a high TIMI-RS, a positive CCTA scan or both (n = 45) resulted in a sensitivity of 95%, specificity of 49%, PPV of 35% and NPV of 97% for having haemodynamically significant coronary lesions. Those with normal perfusion were spared revascularization procedures, regardless of their TIMI-RS.

CONCLUSIONS: Noninvasive assessment of coronary artery disease by SPECT/CCTA may play an important role in risk stratification of patients with NSTE-ACS by better identifying the subgroup requiring intervention.

PMID: 21688049

Posted in Computed Tomography, Nuclear Imaging and tagged , , , .

2 Comments

  1. Interesting paper, which describes the relation between clinical risk assessment and imaging! Perfusion imaging has incremental value by identification of hemodynamically significant lesions (diagnosed by anatomic imaging – CT). The correlation of high TIMI score with obstructive CAD per/CTA is important and says quiet a lot about the usefulness of the TIMI score, as well as of coronary CT.

  2. See also:

    Cost-effectiveness of coronary computed tomography and cardiac stress imaging in the emergency department a decision analytic model comparing diagnostic strategies for chest pain in patients at low risk of acute coronary syndromes.
    Priest VL, Scuffham PA, Hachamovitch R, Marwick TH.
    JACC Cardiovasc Imaging. 2011 May;4(5):549-56.
    PMID: 21565744

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