Evaluation of pleural fluid cytology for the diagnosis of malignant pleural effusion: a retrospective cohort study.

BACKGROUND: Cytological examination of pleural fluid has good specificity, but imperfect sensitivity for the diagnosis of malignant pleural effusion (MPE). Published estimates of sensitivity vary and predictors of false negative cytology are not well established. AIMS: To estimate pleural fluid cytology sensitivity and identify risk factors for false negative cytology. METHODS: We conducted a retrospective cohort study of patients who had cytology testing of pleural fluid at Christchurch Hospital, New Zealand, from July 2017 to October 2019. Data on clinical and pleural fluid characteristics were collected. MPE was defined by positive pleural fluid cytology, tissue histology or multidisciplinary meeting consensus. We estimated sensitivity of the first pleural cytology assessment. We performed multivariate logistic regression to ascertain patient groups at greatest risk of false negative results. RESULTS: Initial pleural fluid cytology was diagnostic in 117 of 156 patients, providing a sensitivity (95% confidence interval (CI)) of 75.0% (67.4-81.6%). The sensitivity was 79.0% (66.8-88.3%) for lung cancer, 91.3% (72.0-98.9%) for breast cancer and 33.3% (95% CI 11.8-61.6%) for mesothelioma. Cloudy appearance of pleural fluid (odds ratio (OR) 0.12; 95% CI 0.03-0.54) and yellow/gold pleural fluid (OR 0.24; 95% CI 0.06-0.96) reduced the odds of false negative pleural cytology. Pleural thickening on computed tomography scan (OR 3.3; 95% CI 1.2-9.4) was a risk factor for false negative cytology. CONCLUSION: Sensitivity of pleural fluid cytology was greatest in primary lung and breast cancer, and lowest in mesothelioma. Clinicians should be alert to false negative results when suspecting mesothelioma or if pleural thickening is present.

Professional killer cell deficiencies and decreased survival in pulmonary arterial hypertension.

BACKGROUND AND OBJECTIVE: Increasing evidence implicates lymphocytes in pulmonary arterial hypertension (PAH) pathogenesis. Rats deficient in T-lymphocytes show increased propensity to develop PAH but when injected with endothelial progenitor cells are protected from PAH (a mechanism dependent on natural killer (NK) cells). A decreased quantity of circulating cytotoxic CD8+ T-lymphocytes and NK cells are now reported in PAH patients; however, the effect of lymphocyte depletion on disease outcome is unknown. METHODS: This prospective study analysed the lymphocyte profile and plasma brain natriuretic peptide (BNP) levels of patients with idiopathic PAH (IPAH), connective tissue disease-associated PAH (CTD-APAH) and matched healthy controls. Lymphocyte surface markers studied include: CD4+ (helper T-cell marker), CD8+ (cytotoxic T-cell marker), CD56/CD16 (NK cell marker) and CD19+ (mature B-cell marker). Lymphocyte deficiencies and plasma BNP levels were then correlated with clinical outcome. RESULTS: Fourteen patients with PAH (9 IPAH, 5CTD) were recruited. Three patients were deceased at 1-year follow-up; all had elevated CD4 : CD8 ratios and deficiencies of NK cells and cytotoxic CD8+ T-lymphocytes at recruitment. Patients with normal lymphocyte profiles at recruitment were all alive a year later, and none were on the active transplant list. As univariate markers, cytotoxic CD8+ T-cell and NK cell counts were linked to short-term survival. CONCLUSIONS: Deficiencies in NK cells and cytotoxic CD8+ T-cells may be associated with an increased risk of death in PAH patients. Further research is required in larger numbers of patients and to elucidate the mechanism of these findings.

ECG score predicts those with the greatest percentage of perfusion defects due to acute pulmonary thromboembolic disease.

BACKGROUND: More aggressive management may be warranted for patients with acute pulmonary embolism (PE) and the greatest pulmonary vascular obstruction. We hypothesized that a scoring system based on the ECG might identify such patients. METHODS: Consecutive patients investigated for PE at Christchurch Hospital between 1997 and 2002 with high-probability ventilation/perfusion (V/Q) scan findings were studied. The ECG obtained closest to and within 48 h of the scan was scored by two independent observers, and the mean ECG score was calculated. V/Q scan findings were categorized into those with < 30%, 30 to 50%, and > 50% perfusion defect by two independent observers experienced in V/Q interpretation. A consensus score was taken when disagreement occurred. RESULTS: Two hundred twenty-nine patients were included in the study. The interobserver agreement for ECG score was 0.96 (Cronbach alpha) and V/Q score was 0.55 (kappa). The ECG predicted those with the greatest amount of perfusion defects. Mean ECG score was 2.6 (SD 2.8) in patients with < 30% perfusion defect, 3.2 (SD 2.9) in patients with 30 to 50% perfusion defect, and 5.3 (SD 3.7) in patients with > 50% perfusion defect. The area under the receiver operating characteristic curve for ECG score and those with > 50% perfusion defect was 0.71 (SE 0.04). An ECG score of > or = 3 predicted those with > 50% perfusion defect with a sensitivity of 70% (95% confidence interval [CI], 59 to 81%), and a specificity of 59% (95% CI, 51 to 67%). CONCLUSION: An ECG score, simple to derive, predicts those with the greatest percentage of perfusion defect. Using the ECG for management warrants prospective evaluation.