Schmermund et al developed a Noninvasive Index ("NI") to identify patients with significant coronary artery disease using clinical data and electron-beam computed tomography (EBCT). This can help target high risk patients for additional testing and therapeutic interventions. The authors are from the Mayo Clinic in Rochester, Minnesota.
Endpoints: angiographically obstructive atherosclerosis, with 3 vessel disease and/or involvement of the left main coronary artery
Parameters:
(1) gender
(2) diabetes mellitus
(3) coronary calcium score (Agatston method) for the left anterior descending (LAD) coronary artery
(4) coronary calcium score (Agatston method) for the left circumflex (LCx) coronary artery
Parameter
Finding
Points
gender
male
1
female
0
diabetes mellitus
present
1
absent
0
noninvasive index =
= LN(LAD calcium score) + LN(LCx calcium score) + (2 * (points for diabetes)) + (3 * (points for gender))
Interpretation:
• minimum score: 0
• maximum score: 20.32 in the Mayo series
• Most patients (72%) had scores either > 14 or < 10.
• An index > 14 increased the post-test probability for angiographically significant coronary artery disease.
• An index < 10 decreased the post-test probability for angiographically significant coronary artery disease.
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