PURPOSE: In Patients with Sickle Cell Disease (SCD), pulmonary microvascular occlusion and infarction ensue leading to alveolar wall necrosis and scarring resulting in loss of lung units. These changes may be subtle and not detected by radiological testing or echocardiography. We sought to determine the prevalence of pulmonary function testing (PFT) abnormalities in patients who had both normal radiological (CXR and chest CT) and echocardiographic evaluation.
METHODS: Clinical data and outcome variables were extracted from the medical records of 29 patients with SCD who underwent PFT for the evaluation of dyspnea at Kings County Hospital Center. A normal radiological evaluation is characterized on x-ray or CT by the absence of pulmonary vascular congestion, infiltrates, cardiomegaly, PA dilatation, pleural effusion or atelectasis. A normal echocardiographic exam is characterized by normal chambers size and function, the absence of valvular heart disease and pulmonary hypertension. NHANES III predictive equations were used.
RESULTS: 19 females and 10 males with SCD (age 31.8±14.8 years) were identified. An abnormally low TLC, FVC or DLCO was present in 93% of the patients. Normal echocardiographic and radiological exams were found in 11/25 (44%) patients with abnormal PFT. Death occurred in 5 patients with a median time of 30 months (95% CI; 15-65 months). Death was associated with a lower FVC (1.8±0.7 vs. 2.7±0.8; p<0.05), a lower FEV1 (1.5±0.5 vs. 2.4±0.7; p<0.05) a lower TLC (2.95±0.8 vs. 4.2±0.9; p<0.05) a higher estimated pulmonary artery pressure (45.3±8.1 vs. 8.1±16.9; p<0.05), an abnormal radiological evaluation (100% vs.48%; p<0.05) and a trend toward a lower DLCO (adjusted to Hgb) (13.4±3.9 vs. 17.9±6.7; NS).
CONCLUSION: Pulmonary function testing is frequently abnormal in SCD patients presenting with dyspnea, and have a high sensitivity in detecting underlying lung disease.
CLINICAL IMPLICATIONS: A normal CXR, chest CT and echocardiography do not rule out underlying pulmonary disease in SCD patients. Routine screening with PFT has a role in the early detection of lung involvement in SCD and identifies a group of patients with a worse prognosis.
DISCLOSURE: Fayez Bader, None.