Pre-test probability of obstructive coronary stenosis in patients undergoing coronary CT angiography: Comparative performance of the modified diamond-Forrester algorithm versus methods incorporating cardiovascular risk factors
Introduction
Estimating the pretest probability of disease is a key step in the evaluation of patients with suspected coronary artery disease (CAD) as this influences clinical decision-making regarding the need for testing, the choice of test, and the interpretation of test results. The current European guidelines on the management of stable CAD recommend a tabular method for estimating pre-test likelihood of obstructive coronary stenosis based exclusively on age, sex and typicality of symptoms. [1] The underlying model uses a modified Diamond-Forrester (MDF) approach, which was extended to include patients older than 70 years, and updated by revising the predictive value of its variables. [2] Despite good internal validation measures, the proposed model was derived entirely from patients referred for invasive coronary angiography (ICA) rather than for non-invasive imaging, for which it is more commonly employed. Further, the MDF method does not account for important cardiovascular risk factors such as diabetes, hypertension or cigarette smoking. To address these shortcomings, new scores that include these risk factors were recently developed from multicenter efforts. The ‘CAD Consortium 2’ was derived from a pooled analysis of 5677 patients undergoing coronary computed tomography angiography (CCTA) and/or ICA in 18 centers in Europe and the United States, [3] while the recent CONFIRM score was developed from a cohort of 9093 patients undergoing CCTA in 8 centers from 6 countries. [4] Importantly, the CAD Consortium 2 score is a calculator-based score, while the CONFIRM score is an integer-based score aimed for easy calculation in the clinical setting.
The aim of this study was to compare the diagnostic performance of these 2 scores against the MDF method in patients referred for non-invasive coronary angiography. The 3 methods were assessed for calibration, discrimination and net reclassification, as well as for their ability to influence clinical decision making for intended downstream testing.
Section snippets
Population
We performed a retrospective analysis on prospectively collected data from a cohort of consecutive patients undergoing CCTA for the evaluation of CAD at our hospital between June 2011 and May 2014. Criteria for referral to CCTA were left to the discretion of the referring physician. Fig. 1 shows patient selection. Age < 30 years, known CAD, suspected acute coronary syndrome, preoperative assessment, and known left ventricular systolic dysfunction were among the exclusion criteria. Asymptomatic
Results
The baseline characteristics of the 1069 symptomatic patients undergoing CCTA for suspected CAD are listed in Table 2. The observed prevalence of obstructive CAD on CCTA was 13.8% (n = 147). Patients with obstructive CAD were more often male, were significantly older and had a higher prevalence of typical angina symptoms and of all the traditional cardiovascular risk factors except for family history. They also had significantly higher CAC scores (median 177, IQR 60–370) than those without
Discussion
In order to be clinically useful, a prediction tool should be well calibrated across the risk spectrum and provide good discrimination between patients with and without the outcome of interest. Overestimation of the likelihood of CAD, in particular, may expose patients to the risks and costs of unnecessary testing and may be partially responsible for the frequently reported low prevalence of obstructive disease in patients undergoing ICA. [2], [11], [12] While several studies have shown
Conclusions
In patients with stable chest pain undergoing CCTA, newer risk factor-encompassing models allow for a more precise estimation of pre-test probabilities of obstructive CAD than the guideline-recommended MDF method. Adoption of these scores may improve disease prediction and change the diagnostic pathway in a significant proportion of patients.
The following are the supplementary data related to this article.
Grant support
None.
Conflicts of interest
The authors report no relationships that could be construed as a conflict of interest.
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Comparison of the CAD consortium and updated Diamond-Forrester scores for predicting obstructive coronary artery disease
2021, American Journal of Emergency MedicineCitation Excerpt :Our study estimated that the CAD consortium clinical model could result in a two-fold increase in the number of patients who can be categorized as low-risk and subsequently would not require additional clinical examination (53% vs 23%). This result adds to the findings of previous studies suggesting that the updated DF model overestimates the likelihood of CAD and is less discriminative than CAD consortium models [7,16]. CAD consortium models, especially the clinical model, were better calibrated than the updated DF model.
Identifying low-risk chest pain in the emergency department: Obstructive coronary artery disease and major adverse cardiac events
2020, American Journal of Emergency MedicineCitation Excerpt :The cardiac troponin I (cTnI-Ultra) assay was performed using Siemens ADVIA Centaur (Siemens, Munich, Germany) with 99th percentile of 0.04 g/L as a cutoff for myocardial necrosis [14]. The pretest probability of obstructive CAD was calculated using three scores: the CAD consortium basic, CAD consortium clinical model, and uDF method [15,16]. We used an updated version of the DF score, which allows the inclusion of patients ≧70 years of age and incorporates age as a continuous variable.
- 1
This author takes responsibility for all aspects of the reliability and freedom from bias of the data presented and their discussed interpretation.