DETECT 2-step screening algorithm

The screening variables are divided into non-echocardiographic parameters that are often routinely obtained by physicians when dealing with SSc patients, and echocardiographic parameters that are usually available after referring the patient for echocardiography.

Step 1 of the algorithm includes the following non-echocardiographic variables: FVC % predicted/DLCO % predicted, current/past telangiectasias, serum anti-centromere antibodies, serum NTproBNP, serum urate, and right axis deviation on ECG. A patient is assigned risk points for each variable, these risk points are added together and the resulting Step 1 total risk score is used to evaluate whether or not the patient should be referred for echocardiography.

Step 2 includes the 2 echocardiographic variables right atrium area and tricuspid regurgitation velocity, as well as the total risk score from Step 1. The patient is assigned risk points for each, and these risk points are added together. The resulting Step 2 total risk score is used to determine whether or not the patient should be referred for right heart catheterization.

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DETECT algorithm and current ESC/ERS guidelines

To determine the added benefit of the DETECT algorithm, the current ESC/ERS guidelines for PAH were applied to the DETECT study patient population. Using the screening recommendations proposed in the current guidelines, PAH would have been missed in 29% of the patients, compared to 4% when utilizing the DETECT algorithm. Although the number of right heart catheterization (RHC) referrals necessary to achieve this excellent result of almost no missed PAH diagnoses is higher when applying the DETECT algorithm (62% vs. 40%), the actual number of patients diagnosed with PAH per 100 RHCs (positive predictive value [PPV]) is very similar (40% vs. 35%).

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Limitations

The DETECT study inclusion criteria selected for prevalent SSc patients (diagnosis of SSc > 3 years).

The DETECT study inclusion criterion "DLCO < 60% (of predicted DLCO)" ensured that  patients with an increased risk of developing PAH were selected.

The DETECT data are based on cross-sectional analyses; it is not possible to prospectively predict individual risk or to recommend how frequently patients should be screened.



Conclusions

The DETECT algorithm for PAH screening in SSc patients is a sensitive, non-invasive screening tool, which minimizes missed diagnoses, identifies even mild disease and optimizes resource utilization.

Reference

The DETECT Study