Background: In systemic sclerosis (SSc), changes in the lungs and pulmonary hypertension (PH) are complications most adversely affecting the prognosis. Given the availability of specific treatment, early diagnosis of PH is very important. Exercise echocardiography, by increasing the patient’s cardiac output, makes it possible to identify patients with elevated pulmonary artery pressure (PAP) during exercise. The diagnostic role of exercise echocardiography is still unclear, mainly because of the lack of prospective studies.
Aim: To identify SSc patients with abnormally elevated PAP at rest or with a significant increase PAP during exercise, subsequently verified by right heart catheterisation (RHC).
Methods: A total of 71 consecutive patients (67 females and 4 males, mean age 56.9 ± 17.1 years) with SSc diagnosed according to the American College of Rheumatology criteria were enrolled in this prospective study. The patients underwent transthoracic echocardiography (Philips iE33) with the measurement of tricuspid regurgitation peak gradient (TRPG) and an exercise test involving the standard treadmill exercise according to the Bruce protocol with the evaluation of TRPG at 1 min following the completion of exercise. The PH was suspected when TRPG at rest was > 31 mm Hg (V_max > 2.8 m/s) or increased by at least 20 mm Hg from baseline following exercise. Patients with suspected PH were referred for resting and exercise RHC.
Results: The exercise testing was performed in 67 patients revealing normal left ventricular (LV) systolic function in all of them. The mean LV ejection fraction was 66.1% ± 3.9%. The TRPG at rest could be recorded in 65 (97%) patients with the mean value of 26.9 ± ± 7.6 mm Hg (range 17–57 mm Hg). A resting TRPG of > 31 mm Hg, suggestive of possible PH, was demonstrated in 14 (21%) patients. During exercise test 56 (84%) patients achieved the maximum heart rate. A Doppler spectrum enabling the measurement of TRPG following the exercise was obtained in 66 (98.5%) patients. The gradient following the exercise could not be measured in one patient with a resting TRPG of 30 mm Hg. The mean post-exercise TRPG was 40.3 ± 4.1 mm Hg (range 17–70) and the mean post-exercise increase in TRPG was 12.9 ± 8.5 mm Hg (range 2–38). A TRPG increase of > 20 mm Hg was found in 11 (16%) patients (including 4 patients with resting values exceeding 31 mm Hg and 7 patients with normal resting values). Twenty-one (31%) patients with echocardiographic suspicion of PH (TRPG > 31 mm Hg at rest and/or a post-exercise increase in TRPG of more than 20 mm Hg) were referred for RHC with 16 patients actually undergoing the procedure. Four out of these 16 patients were qualified because of the “positive” exercise echocardiography in the presence of normal TRPG values. During catheterisation arterial PH was found in 2 patients, and an excessive precapillary PAP elevation in 2 further patients. Resting venous PH was found in 1 patient and an excessive postcapillary PAP elevation at rest was demonstrated in 11 patients.
Conclusions: Exercise echocardiography is a safe and useful screening tool for PH diagnosis in patients with SSc. It enables to identify patients with normal systolic PAP at rest but a significant increase during exercise. The final confirmation of PH and differentiation between precapillary arterial and postcapillary venous PH requires RHC.
Kardiol Pol 2011; 69, 1: 9-15