Oxygen Therapy in Patients With Intermediate-Risk Acute Pulmonary Embolism: A Randomized Trial

BACKGROUND

The effect of supplemental oxygen therapy in patients with intermediate-risk pulmonary embolism (PE) who do not have hypoxemia at baseline is uncertain.

RESEARCH QUESTION

Does supplemental oxygen improve echocardiographic parameters in nonhypoxemic patients with intermediate-risk PE?

STUDY DESIGN AND METHODS

This pilot trial randomly assigned nonhypoxemic patients with stable PE and echocardiographic right ventricle (RV) enlargement to receive anticoagulation plus supplemental oxygen for the first 48 h vs anticoagulation alone. The primary outcome was normal echocardiographic RV size 48 h after randomization. Secondary efficacy outcomes were the numerical change in the RV to left ventricle (LV) diameter ratio measured 48 h and 7 days after randomization with respect to the baseline ratio measured at inclusion.

RESULTS

The study was stopped prematurely because of the COVID-19 pandemic after recruiting 70 patients (mean ± SD age, 67.3 ± 16.1 years; 36 female [51.4%]) with primary outcome data. Forty-eight h after randomization, normalization of the RV size occurred in 14 of the 33 patients (42.4%) assigned to oxygen and in eight of the 37 patients (21.6%) assigned to ambient air (P = .08). In the oxygen group, the mean RV to LV ratio was reduced from 1.28 ± 0.28 at baseline to 1.01 ± 0.16 at 48 h (P < .001); in the ambient air group, mean RV to LV ratios were 1.21 ± 0.18 at baseline and 1.08 ± 0.19 at 48 h (P < .01). At 90 days, one major bleeding event and one death (both in the ambient air group) had occurred.

INTERPRETATION

In analyses limited by a small number of enrollees, compared with ambient air, supplemental oxygen did not significantly increase the proportion of patients with nonhypoxemic intermediate-risk PE whose RV to LV ratio normalized after 48 h of treatment. This pilot trial showed improvement in some ancillary efficacy outcomes and provides support for a definitive clinical outcomes trial.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT04003116; URL: www.

CLINICALTRIALS

gov.

Nocturnal hypoxemia and prognosis in patients with acute symptomatic pulmonary embolism

BACKGROUND

Nocturnal hypoxemia has been associated with cardiovascular and non-cardiovascular morbidity and mortality. This study aimed to investigate the prognostic value of nocturnal hypoxemia among patients with hemodynamically stable acute symptomatic pulmonary embolism (PE).

METHODS

We performed an ad hoc secondary analysis of clinical data from a prospective cohort study. Nocturnal hypoxemia was measured by the percent sleep registry with oxygen saturation <90% [TSat90]). Outcomes assessed over the 30-days after the diagnosis of PE included PE-related death, other cardiovascular deaths, clinical deterioration requiring an escalation of treatment, recurrent venous thromboembolism (VTE), acute myocardial infarction [AMI], or stroke.

RESULTS

Of the 221 hemodynamically stable patients with acute PE from which the TSat90 could be calculated and did not receive supplemental oxygen, the primary outcome occurred in 11 (5.0%; 95% confidence interval [CI], 2.5% to 8.7%) within 30-days after the diagnosis of PE. When categorized by quartiles, TSat90 was not significantly associated with the occurrence of the primary outcome in unadjusted Cox regression analysis (hazard ratio, 0.96; 95% CI, 0.57 to 1.63; P = 0.88), or after adjustment for body mass index (adjusted hazard ratio, 0.97; 95% CI, 0.57 to 1.65; P = 0.92). When examined as a completely continuous variable (between 0 and 100), TSat90 was not associated with a significant increase in the adjusted hazard of 30-day primary outcome rates (hazard ratio, 0.97; 95% CI, 0.86 to 1.10; P = 0.66).

CONCLUSIONS

In this study, nocturnal hypoxemia did not identify stable patients with acute symptomatic PE at increased risk for adverse cardiovascular events.

National Early Warning Score-2 for Identification of Patients with Intermediate-High-Risk Pulmonary Embolism

Consensus statements have proposed the use of the National Early Warning Score 2 (NEWS2) to identify stable patients with acute pulmonary embolism (PE) and an intermediate-high risk of adverse outcomes. We aimed to externally validate NEWS2 and compare it to another predictive score (Bova). Using NEWS2 (cutoff ≥5 and ≥7) and the Bova score (cutoff >4), we classified patients as intermediate-high risk (vs. non-intermediate-high risk), and we compared the test characteristics of these risk classification tools for a complicated course within 30 days after PE diagnosis. We also assessed the validity of NEWS2 for predicting a complicated course by adding the results of echocardiography and troponin testing to the model. Of the 848 enrolled patients, the NEWS2 score ≥5 classified 471 (55.5%) and the Bova score classified 37 (4.4%) as intermediate-high risk. NEWS2 had a significantly lower specificity for a 30-day complicated course than Bova (45.4 vs. 96.3%, respectively; p < 0.001). Using the higher score threshold (≥7), the NEWS2 classified 99 (11.7%) as intermediate-high risk, and the specificity was 88.9% (difference with Bova, 7.4%; p < 0.001). The proportion of patients with intermediate-high risk PE was 2.4% for the combination of a positive troponin testing and echocardiographic right ventricle dysfunction and a positive NEWS2 (score ≥7), while the specificity was 97.8% (difference with Bova, 1.5%; p = 0.07). Bova outperforms NEWS2 for predicting a complicated course among stable patients with PE. Addition of troponin testing and echocardiography improved the specificity of NEWS2, although it was not superior to Bova. CLINICALTRIALS.GOV NUMBER: : NCT02238639.

The rationale, design, and methods of a trial to evaluate the efficacy and safety of oxygen therapy in patients with intermediate-risk acute pulmonary embolism

BACKGROUND

In patients with intermediate-risk pulmonary embolism (PE), reversal of hypoxic vasoconstriction could constitute a target for treatment that protects the right ventricular (RV) function until endogenous fibrinolysis occurs. The Air vs oxygen for Intermediate-Risk pulmonary embolism (AIR) trial aims to assess the effect of oxygen therapy in patients with intermediate-risk acute PE who do not have hypoxemia at baseline.

METHODS AND ANALYSES

AIR is a prospective, multicenter, randomized, open-label, parallel-group, proof-of-concept trial. A total of 90 patients hospitalized with intermediate-risk PE and an oxygen saturation of 90% or higher at baseline will be randomized in a 1:1 fashion to receive supplemental oxygen or ambient air. The primary outcome is a RV/LV diameter ratio equal or less than 1.0 on echocardiography measured 48 hours after the start of treatment. Secondary efficacy outcomes are the numerical change in the ratio of the RV to the LV diameter measured 48 hours and 7 days after the start of treatment, with respect to the baseline ratio measured at randomization. Clinical adverse events will be also collected.

RESULTS

Enrollment started in July 2019 and is expected to proceed until 2022. Median age of the first 50 patients was 74 years (interquartile range, 61-81), and 50% were female.

CONCLUSIONS

This multicenter trial will provide information about the value of supplemental oxygen in patients with intermediate-risk acute PE who do not have hypoxemia at baseline. The results will contribute to research that may assist patients with intermediate-risk PE in the future.

Comparison of various prognostic scores for identification of patients with intermediate-high risk pulmonary embolism

BACKGROUND

Various risk assessment tools have been proposed to identify stable patients with acute pulmonary embolism (PE) who are at high risk of early adverse outcome (i.e., intermediate-high risk).

METHODS

We evaluated the ability of the 2019 ESC, Bova, modified FAST and PEITHO-3 models for predicting a 30-day complicated course (death, haemodynamic collapse, and/or recurrent PE) in a cohort of 848 stable patients with acute PE. We also tested whether replacement of echocardiographic right ventricle (RV) dysfunction by computed tomographic (CT) RV enlargement provides comparable prognostic information for identifying these patients.

RESULTS

A complicated course occurred in 63 (7.4 %) of the 848 patients with PE during the first month of follow-up. The proportion of patients designated as having intermediate-high risk PE was 6.7 % with the ESC model, 4.4 % with the Bova score, 15.7 % with the FAST score, and 5.2 % with the PEITHO-3 model. However, among patients identified as intermediate-high risk, the 30-day complicated course rate was higher with the Bova score (21.6 %) than with the ESC model (17.5 %), the PEITHO-3 model (15.9 %), or the modified FAST score (14.3 %). When echocardiographic RV dysfunction was replaced by CT RV enlargement in the models, the proportion of patients classified as having intermediate-high risk PE and the rate of an adverse outcome among them slightly increased.

CONCLUSIONS

The Bova score might identify patients with intermediate-high risk PE slightly better than the ESC, PEITHO-3, and modified FAST score. When echocardiography is not readily available, CT-assessed RV enlargement might be used for identifying intermediate-high risk PE.

CLINICALTRIALS

gov number: NCT02238639.

Significado pronóstico de los diagnósticos alternativos a la TEP hallados en la tomografía computarizada de tórax de pacientes ingresados por agudización de EPOC: subanálisis predefinido del ensayo SLICE

BACKGROUND

Among patients hospitalized for an exacerbation of chronic obstructive pulmonary disease (COPD), the SLICE trial showed that the addition of an active diagnostic strategy for pulmonary embolism (PE) to usual care compared with usual care alone did not improve a composite set of health outcomes. The objective of this subanalysis was to determine the frequency and prognostic significance of findings on computed tomography pulmonary angiogram (CTPA) supporting an alternative diagnosis to PE.

METHODS

We analyzed all patients randomized to the intervention in the SLICE trial who received a CTPA that did not show PE. We used multivariable logistic regression to assess the independent association between findings supporting an alternative diagnosis to PE and a composite of readmission for COPD or death within 90 days after randomization.

RESULTS

Among the 746 patients who were randomized, this subanalysis included 175 patients in the intervention group who received a CTPA that did not show PE. Eighty-four (48.0%) patients had acute bronchial infection, 13 (7.4%) had lung cancer, 10 (5.7%) had congestive heart failure, 8 (4.6%), 18 (10.3%) had other diagnoses, and 42 (24.0%) had a normal CTPA. In multivariable analysis, findings supporting an alternative diagnosis to PE were not significantly associated with the primary outcome (odds ratio: 0.64; 95% confidence interval: 0.30-1.38; P=0.26).

CONCLUSIONS

Among patients hospitalized for an exacerbation of COPD, CTPA identified an alternative diagnosis in 76% of the patients. However, specific management of these patients was not associated with improved outcomes within 90 days after randomization.