POS0856 CLINICAL UTILITY OF BREATH-HOLDING TEST FOR MEASURING CARDIOPULMONARY FUNCTION IN PATIENTS WITH SYSTEMIC SCLEROSIS

Abstract

Background:Interstitial lung disease (ILD) and pulmonary arterial hypertension (PAH) are major causes of death in systemic sclerosis (SSc). Six-minute-walk test (6MWT) is a standard outcome measure for exercise capacity in cardiopulmonary diseases. However, the results of 6MWT may not reflect real cardiopulmonary function of SSc patients in whom musculoskeletal system is frequently inflicted.Objectives:This study aimed to evaluate the clinical utility of breath-holding test (BHT) in evaluating cardiopulmonary function in SSc patients, as compared with 6MWT.Methods:Seventy-two patients with SSc were prospectively enrolled and underwent BHT and 6MWT with measurement of Borg score and Scleroderma Health Assessment Questionnaire (SHAQ). Data on diffusing capacity for carbon monoxide (DLCO, %), forced vital capacity (FVC, % and liters), and ejection fraction and pulmonary arterial systolic pressure (PASP) measured by transthoracic echocardiography (TTE), were also collected. For BHT, participants were required to make a maximum expiration followed by a maximum inspiration and to hold the breath as long as possible at maximum inspiratory level. This procedure was repeated three times, with 5-minute intervals. 6MWT was performed according to the American Thoracic Society guidelines. Pearson’s correlation test was applied to demonstrate the relationship between BHT results and each clinical parameter.Results:Among 72 (66 female) patients, mean (SD) age was 57.1 (11.1) years, modified Rodnan skin score 10.6 (10.5), SHAQ 0.64 (0.61) and 6MWT distance 473.5 (95.5) m. Mean BHT time was 35.05 (14.90) sec at the first time, 38.92 (16.14) sec at the second time, and 41.11 (17.71) sec at the third time. The BHT time showed a statistically significant negative correlation with Borg scale (pre-test, r = -0.336, p = 0.002; post-test, r = -0.252, p = 0.034; Figure 1 and Table 1), while 6MWT showed a negative correlation with only post-test Borg scale (pre-test, r = -0.113 p = 0.343; post-test, r = -0.351 p = 0.002; Table 1). The BHT time was positively correlated with DLCO (%, r = 0.409, p < 0.001) and FVC (liters, r = 0.402, p < 0.001) (Table 1). We also found a statistically significant correlation between BHT time and SHAQ score (r = -0.451, p < 0.001; Table 1). However, EF and PASP by TTE showed no significant relationship with BHT time (EF, r = -0.108, p = 0.374; PASP, r = -0.246, p = 0.054; Table 1).Table 1.Pearson’s correlation coefficients (r) for the relation between BHT and clinical parameters in comparison to 6MWT.Pre-test Borg scalePost-test Borg scaleDLCO(%)FVC(L)FVC(%)FVC/DLCOEF(%)PSAP(mm Hg)SHAQ (score)BHT (sec)-0.366**-0.252*0.409***0.402**0.191-0.244***-0.108-0.246-0.451***6MWT (m)-0.113-0.351**0.297*0.321**0.063-0.250*0.137-0.354**-0.531***BHT, breath-holding test; 6MWT, 6-minute-walk test; DLCO, diffusing capacity for carbon monoxide; FVC, forced vital capacity; EF, ejection fraction estimated by transthoracic echocardiography; SHAQ, Scleroderma Health Assessment Questionnaire.* p < 0.05, ** p < 0.01, *** p < 0.001Figure 1.Association of Borg dyspnea scale with breath-holding time.Conclusion:The BHT is a simple, safe, and less time-consuming test, reflective of pulmonary parameters and SHAQ, as compared with 6MWT. Our results suggest that the BHT might be a useful surrogate marker of cardiopulmonary capacity in SSc patients.