ESC Pretest Probability Scores More Accurately Predict CAD Than Diamond and Forrester Score
Is the Diamond and Forrester (DF) score to assess pretest probability for coronary artery disease (CAD) more accurate than the two CAD consortium scores recently recommended by the European Society of Cardiology (ESC)?
The study cohort included 2,274 consecutive patients (ages 56 ± 13 years, 57% males) without prior CAD referred for coronary computed tomography angiography (CTA). CTA findings were used to determine the presence or absence of obstructive CAD (≥50% stenosis). The DF score was compared with the two CAD consortium scores (basic and clinical model) with respect to their ability to predict obstructive CAD.
The DF score did not satisfactorily fit the data, and resulted in a significant overestimation of the prevalence of obstructive CAD (p < 0.001). The CAD consortium basic model had no significant lack of fitness, while the CAD consortium score with clinical data provided adequate goodness-of-fit (p = 0.39). The DF had a lower discrimination for obstructive CAD, with an area under the receiver operating characteristic curve of 0.713 versus 0.752, and 0.791 for the CAD consortium models (p < 0.001 for both). Consequently, the use of the DF score was associated with fewer individuals being categorized as requiring no additional testing (8.3%) when compared to the CAD consortium models (24.6% and 30.0%, p < 0.001). The proportion of individuals with a high pretest probability was 18% with the DF and only 1.1% with the CAD consortium scores (p < 0.001). In a median follow-up of 3.3 years, 6.5% had a major cardiovascular event that was better predicted by the CAD consortium clinical model.
Among contemporary patients referred for noninvasive testing, the DF risk score overestimates the risk of obstructive CAD. On the other hand, the CAD consortium scores offered improved goodness-of-fit and discrimination, and thus, their use could decrease the need for noninvasive or invasive testing, while increasing the yield of such tests.
The findings support using either of the two ESC CAD consortium scores rather than DF as a pretest screen of persons with chest pain, as they are more accurate at identifying ≥50% stenosis and outcome as well as much better at identifying persons at low risk and for whom no further testing may be necessary. There is no suggestion that CTA should be the preferred screening test for stable chest pain. A significant percentage of participants in this study may have had an exercise electrocardiogram (ECG) or other stress imaging prior to the CTA. Identifying a >50% stenosis is not the clinical objective. The authors previously reported that extensive nonobstructive CAD burden is associated with the same three-fold risk of cardiovascular events as obstructive disease, and a low-risk (Duke treadmill score) exercise ECG has a good prognosis.
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