PAH rare in systemic lupus erythematosus
medwireNews: The prevalence of pulmonary arterial hypertension (PAH) is very low among patients with systemic lupus erythematosus (SLE), say researchers.
The team found that unexplained dyspnoea was a strong predictive factor, although it identified occult left heart disease as readily as pulmonary hypertension in the study cohort of 152 patients with SLE.
Three of these patients had previously diagnosed PAH; the others were examined using an algorithm that began with Doppler echocardiography. Patients with systolic pulmonary artery pressure of 45 mmHg or higher underwent right heart catheterisation (RHC), while those with lower pressures underwent tests including exercise Doppler echocardiography and assessment of dyspnoea and N-terminal pro–brain natriuretic peptide (NT-proBNP) levels to determine their need for RHC and, potentially, exercise RHC.
Despite this “comprehensive approach”, the team did not identify any additional patients with PAH, instead finding one with chronic thromboembolic pulmonary hypertension and five with exercise-induced pulmonary artery pressure increase (EPAPI).
This gave an overall pulmonary hypertension prevalence of 2.6% (including the three previously identified patients), which Gregorio Pérez-Peñate (Hospital Universitario General de Gran Canaria “Doctor Negrín”, Madrid, Spain) and co-researchers say is in line with some previous studies, but not others, which reported rates of up to 17.5%.
These studies “may have overestimated the real prevalence by failure in pre/post-capillary discrimination”, the team suggests in The Journal of Rheumatology.
One of the patients in the current study with EPAPI was thought to have possible early PAH, while the other four had occult left heart dysfunction, identified by exercise RHC, which was the final stage in the algorithm.
The researchers found that “exercise hemodynamic measurements are of incremental value for left heart diastolic dysfunction detection and may provide a window into earlier diagnosis of this condition.”
Patients identified by the algorithm had more unexplained dyspnoea, compared with other patients, as well as increased NT-proBNP levels and reduced diffusion capacity of the lungs for carbon monoxide. But the team notes that although dyspnoea was a particularly prominent predictor, it was frequently caused by undetected left heart dysfunction, rather than by PAH.
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