Can FVC/DLCO predict pulmonary hypertension in patients with chronic obstructive pulmonary disease?

S. Beyhan Sagmen, A. Fidan

Department of Pulmonary Medicine, University of Health Science, Kartal Dr. Lutfi Kirdar Training and Research Hospital, Istanbul, Turkey. sedabeyhansagmen@gmail.com

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• Respiratory Medicine

OBJECTIVE: The aim of the study was to investigate pulmonary function parameters in patients who did and did not have pulmonary hypertension, and the roles of forced vital capacity (FVC)/diffusing capacity of the lungs for carbon monoxide (DLCO) and FVC/DLCO/alveolar volume (VA) values in patients with COPD accompanied by pulmonary hypertension.

PATIENTS AND METHODS: This study included patients with stable and advanced COPD (groups C and D), who presented to the Chest Diseases outpatient clinic at our hospital. Parameters of age and sex, use of long-term oxygen therapy at home, and pulmonary function parameters were evaluated. In addition, systolic pulmonary artery pressure (sPAP) was evaluated on a transthoracic echocardiogram (TTE). Patients were grouped according to TTE sPAP values > 36, and those with normal sPAP values. The pulmonary function parameters of the two groups were compared.

RESULTS: PAP was found to be high in 19 patients (33.33%) and normal in 38 patients (66.67%). The BMI of the group with high PAP (23.54 ± 4.18) was also lower, compared to the group with normal PAP (26.91 ± 4.58) (p=0.010). The FVC/DLCO ratio of the group with high PAP (1.88 ± 0.69) was found to be higher compared to the group with normal PAP (0.90 ± 0.19) (p<0.001). The mean FVC/DLCO/VA ratio was higher in the group with high PAP (1.30 ± 0.68) compared to the group with normal PAP (p=0.001). When determining the height of PAP, cut-off values were examined for FVC/DLCO and FVC/DLCO/VA ratios. When the cut-off value for the FVC/DLCO ratio was taken as 1.31, the sensitivity was 96.8%, the specificity was 97.37%, the PPV was 95.00%, and the NPV was 92.86%. When the cut-off value for the FVC/DLCO/VA ratio was taken as 1.09, the sensitivity was 68.42%, the specificity was 97.37%, the PPV was 100.0%, and the NPV was 86.05%.

CONCLUSIONS: The FVC/DLCO and FVC/DLCO/VA ratios can be important to predict increased PAP in patients with COPD. Pulmonary function tests, which are performed as a routine, have gained importance in clinical practice for the detection of pulmonary hypertension in patients with COPD.

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