Cardiopulmonary exercise testing in combination with the DETECT algorithm may be a useful tool in screening patients with systemic sclerosis (SSc) for pulmonary arterial hypertension, according to results of a report published in Rheumatology.
Consecutive adult patients with SSc were screened using the DETECT algorithm between June 2017 and February 2019. Pulmonary function tests were performed and blood samples were collected according to the DETECT approach.
In total, 314 patients with SSc were screened and 96 met the DETECT entry criteria. Of these patients, 76 passed DETECT step 1, and 54 passed step 2; these patients were referred for cardiopulmonary exercise testing and right-heart catheterization.
Overall, 42.6% of patients had precapillary pulmonary hypertension; 5.5% had postcapillary pulmonary hypertension. Pulmonary arterial hypertension was identified in 31.5% of patients, according to the European Society of Cardiology/European Respiratory Society 2015 guidelines. High-resolution computed tomography scans identified interstitial lung disease in 7 patients, 4 of whom had mild cases and 3 of whom had intermediate cases.
Investigators found that minute ventilation to carbon dioxide production (VE/VCO2) at the first ventilatory threshold had a sensitivity of 1.0 in 63% of models, a median sensitivity of 1.0 (range, 0.857-1.000), and a specificity of 0.833 (range, 0.769-0.882). Positive predictive and negative predictive values were 0.7 and 1.0 (ranges, 0.6-0.8 and 0.923-1.000), respectively. The sensitivity of the VE/VCO2 slope was 1.0 in 87% of models, with a median sensitivity of 1.0, a specificity of 0.778, a positive predictive value of 0.636, and a negative predictive value of 1.0.
When considering precapillary pulmonary hypertension, the investigators found that the VE/VCO2 at the first ventilatory threshold had a sensitivity of 1.0, a specificity of 0.455, a positive predictive value of 0.571, and a negative predictive value of 1.0 with perfect sensitivity in 63.1% of models. In addition, the VE/VCO2 slope had a sensitivity of 1.0, a specificity of 0.714, a positive predictive value of 0.714, and a negative predictive value of 1.0, with a maximum sensitivity in 63.7% of models.
No other cardiopulmonary exercise testing or echocardiographic variables had a substantial effect on DETECT performance.
Study limitations included the small sample size and lack of external population; researchers were unable to test the generalizability of their approach.
“[Cardiopulmonary exercise testing] appears to be a promising, noninvasive tool in the screening workup for SSc-related pulmonary hypertension,” the researchers concluded.
Santaniello A, Casella R, Vicenzi M, et al. Cardiopulmonary exercise testing in a combined screening approach to individuate pulmonary arterial hypertension in systemic sclerosis [published online October 21, 2019]. Rheumatology. doi:10.1093/rheumatology/kez473