Prognostic significance of PaO2/PaCO2 ratio in normotensive patients with pulmonary embolism.

INTRODUCTION: Risk stratification remains controversial in patients with normotensive pulmonary embolism (PE). The debate has recently focused right ventricular dysfunction detected by echocardiography or spiral computed tomography (CT) and cardiac biomarkers. OBJECTIVES: The utility of the PaO(2)/PaCO(2) ratio to predict the short-term prognosis of PE is not currently known and that is the aim of the present study. MATERIALS AND METHODS: This study retrospectively enrolled 99 (34 males, 65 females, 67 ± 15 years) consecutive patients with acute PE, diagnosed by spiral chest tomography pulmonary angiography (CTPA). On admission, cardiac troponin T (cTn-T) was measured and on CTPA both right ventricle diameter and left ventricle diameter was calculated (RV/LV ratio). During the first 24 h after admission, all the patients had initial arterial blood gas collected under room air. Receiver-operating characteristic (ROC) analysis was performed to determine the optimal PaO(2)/PaCO(2), RV/LV ratio and cTn-T cutoff level with regard to prognosis. RESULTS: In-hospital mortality was 12.1% and all-cause 90-day mortality was 15.2%. Ten of 15 patients who died had a PaO(2)/PaCO(2) ≤ 1.8 based on ROC analysis (P < 0.014).The cutoff level of PaO(2)/PaCO(2) ≤ 1.8 had a high negative predictive value of 93% for mortality. Multivariable analysis revealed that PaO(2)/PaCO(2) ≤ 1.8 Hazard Ratio (HR): 16.8 [95% CI: 2.6-108, P < 0.003] was the most significant independent predictor, whereas cTn-T, pO(2) < 60 mmHg and cardiac failure were nonsignificant factors. In addition, PaO(2)/PaCO(2) ≤ 1.8 showed significant survival differences for overall mortality rates in Kaplan-Meier analysis (P < 0.012). CONCLUSION: The PaO(2)/PaCO(2) measurement is a highly useful and practical measurement to predict prognosis in patients with acute PE. Moreover, it appears to be a more accurate predictor than RV/LV ratio and cTn-T levels in patients with normotensive PE.

The role of risk factors in delayed diagnosis of pulmonary embolism.

BACKGROUND: Despite diagnostic advances, delays in the diagnosis of pulmonary embolism (PE) are common. OBJECTIVE: In this study, we aimed to investigate the relationship between delays in the diagnosis of PE and underlying risk factors for PE. METHODS: We retrospectively evaluated the records of 408 patients with acute PE. Patients were divided into 2 groups, surgical or medical, based on risk factors leading to the embolism. Analysis involved demographic characteristics of the patients, dates of symptom onset, first medical evaluation, and confirmatory diagnostic tests. Diagnostic delay was described as diagnosis of PE more than 1 week after symptom onset. RESULTS: The mean time to diagnosis for all patients was 6.95 ± 8.5 days (median, 3 days; range, 0-45 days). Of the total number of patients, 29.6% had presented within the first 24 hours and 72.3% within the first week. The mean time to diagnosis was 4.4 ± 7.6 days (median, 2 days; range, 0-45 days) in the surgical group and 8.0 ± 8.6 days (median, 4 days; range, 0-45 days) in the medical group (P = .000). The mean time to diagnosis in the medical group was approximately 4 times greater than that of the surgical group on univariate analysis. Early or delayed diagnosis had no significant impact on mortality in either group. CONCLUSION: Delay in the diagnosis of PE is an important issue, particularly in medical patients. We suggest that a public health and educational initiative is needed to improve efficiency in PE diagnosis.

Combined risk stratification with computerized tomography /echocardiography and biomarkers in patients with normotensive pulmonary embolism.

BACKGROUND: Right ventricular dysfunction (RVD) detected by computerized tomography (CT)/echocardiography or elevated biomarkers is associated with a poor prognosis for pulmonary embolism (PE). However, these prognostic factors have not previously been concomitantly elucidated in the same patient group. METHODS: This prospective study included 108 consecutive patients with normotensive PE confirmed by CT pulmonary angiography (CTPA). On admission, patient serum NT-proBNP and troponin T (Tn-T) levels were measured, and echocardiography was performed within 24 hours after diagnosis of PE. Receiver operating characteristic (ROC) analysis was performed to determine the optimal echocardiographic end-diastolic diameters of the right ventricle, the ratio of the right ventricle to left ventricle (RV/LV ratio) on CTPA, and NT-proBNP and Tn-T cut-off levels with regard to prognosis. RESULTS: All-cause 30-day mortality was 13% and PE-related mortality was 5.6%. RVD was defined as a right/left ventricular dimension ratio≥1.1 on CTPA and RV>30 mm on echocardiography by ROC analysis. A cut-off level of NT-proBNP≤90 pmol/ml had a high positive predictive value of 98% for survival, whereas NT-proBNP>300 and Tn-T≥0.027 had a negative predictive value, for all-cause deaths, of 95% and 96%, respectively. PE mortality in patients with NT-proBNP>300 and Tn-T≥0.027 reached 64%. In univariable analysis, the combination of Tn-T≥0.027 ng/ml with a echocardiographic RVD were the most significant predictors of overall mortality and PE-related death [HR: 14 (95% CI: 4.6-42,) and HR: 37.6 (95% CI: 4.4-324)], respectively. In multivariable Cox's regression analysis, NT-proBNP>300 and Tn-T≥0.027 HR: 26.5 (95% CI: 4.1-169.9, p<0.001) were the best combination to predict all-cause of mortality. CONCLUSIONS: The combination of NT-proBNP and Tn-T clearly appears to be a better risk stratification predictor than biomarkers plus RVD on CT/ echocardiography in patients with normotensive PE.