Dataset Information

Oxygen therapy for acute myocardial infarction.

ABSTRACT:

Background

Oxygen (O₂) is widely used in people with acute myocardial infarction (AMI). Previous systematic reviews concluded that there was insufficient evidence to know whether oxygen reduced, increased or had no effect on heart ischaemia or infarct size. Our first Cochrane review in 2010 also concluded there was insufficient evidence to know whether oxygen should be used. Since 2010, the lack of evidence to support this widely used intervention has attracted considerable attention, prompting further trials of oxygen therapy in myocardial infarction patients. It is thus important to update this Cochrane review.

Objectives

To assess the effects of routine use of inhaled oxygen for acute myocardial infarction (AMI).

Search methods

We searched the following bibliographic databases on 6 June 2015: the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, MEDLINE (OVID), Embase (OVID), CINAHL (EBSCO) and Web of Science (Thomson Reuters). LILACS (Latin American and Caribbean Health Sciences Literature) was last searched in September 2016. We also contacted experts to identify eligible studies. We applied no language restrictions.

Selection criteria

Randomised controlled trials in people with suspected or proven AMI (ST-segment elevation myocardial infarction (STEMI) or non-STEMI) within 24 hours after onset, in which the intervention was inhaled oxygen (at normal pressure) compared to air, regardless of co-therapies provided to participants in both arms of the trial.

Data collection and analysis

Two authors independently reviewed the titles and abstracts of identified studies to see if they met the inclusion criteria and independently undertook the data extraction. We assessed the quality of studies and the risk of bias according to guidance in the Cochrane Handbook for Systematic Reviews of Interventions. The primary outcome was death. The measure of effect used was the risk ratio (RR) with a 95% confidence interval (CI). We used the GRADE approach to evaluate the quality of the evidence and the GRADE profiler (GRADEpro) to import data from Review Manager 5 and create 'Summary of findings' tables.

Main results

The updated search yielded one new trial, for a total of five included studies involving 1173 participants, 32 of whom died. The pooled risk ratio (RR) of all-cause mortality in the intention-to-treat analysis was 0.99 (95% CI 0.50 to 1.95; 4 studies, N = 1123; I² = 46%; quality of evidence: very low) and 1.02 (95% CI 0.52 to 1.98; 4 studies, N = 871; I² = 49%; quality of evidence: very low) when only analysing participants with confirmed AMI. One trial measured pain directly, and two others measured it by opiate usage. The trial showed no effect, with a pooled RR of 0.97 for the use of opiates (95% CI 0.78 to 1.20; 2 studies, N = 250). The result on mortality and pain are inconclusive. There is no clear effect for oxygen on infarct size (the evidence is inconsistent and low quality).

Authors' conclusions

There is no evidence from randomised controlled trials to support the routine use of inhaled oxygen in people with AMI, and we cannot rule out a harmful effect. Given the uncertainty surrounding the effect of oxygen therapy on all-cause mortality and on other outcomes critical for clinical decision, well-conducted, high quality randomised controlled trials are urgently required to inform guidelines in order to give definitive recommendations about the routine use of oxygen in AMI.

SUBMITTER: Cabello JB

PROVIDER: S-EPMC6463792 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:BackgroundPreclinical data suggest that an acute inflammatory response following myocardial infarction (MI) accelerates systemic atherosclerosis. Using combined positron emission and computed tomography, we investigated whether this phenomenon occurs in humans.Methods and resultsOverall, 40 patients with MI and 40 with stable angina underwent thoracic 18F-fluorodeoxyglucose combined positron emission and computed tomography scan. Radiotracer uptake was measured in aortic atheroma and nonvascular tissue (paraspinal muscle). In 1003 patients enrolled in the Global Registry of Acute Coronary Events, we assessed whether infarct size predicted early (≤30 days) and late (>30 days) recurrent coronary events. Compared with patients with stable angina, patients with MI had higher aortic 18F-fluorodeoxyglucose uptake (tissue-to-background ratio 2.15±0.30 versus 1.84±0.18, P<0.0001) and plasma C-reactive protein concentrations (6.50 [2.00 to 12.75] versus 2.00 [0.50 to 4.00] mg/dL, P=0.0005) despite having similar aortic (P=0.12) and less coronary (P=0.006) atherosclerotic burden and similar paraspinal muscular 18F-fluorodeoxyglucose uptake (P=0.52). Patients with ST-segment elevation MI had larger infarcts (peak plasma troponin 32 300 [10 200 to >50 000] versus 3800 [1000 to 9200] ng/L, P<0.0001) and greater aortic 18F-fluorodeoxyglucose uptake (2.24±0.32 versus 2.02±0.21, P=0.03) than those with non-ST-segment elevation MI. Peak plasma troponin concentrations correlated with aortic 18F-fluorodeoxyglucose uptake (r=0.43, P=0.01) and, on multivariate analysis, independently predicted early (tertile 3 versus tertile 1: relative risk 4.40 [95% CI 1.90 to 10.19], P=0.001), but not late, recurrent MI.ConclusionsThe presence and extent of MI is associated with increased aortic atherosclerotic inflammation and early recurrent MI. This finding supports the hypothesis that acute MI exacerbates systemic atherosclerotic inflammation and remote plaque destabilization: MI begets MI.Clinical trial registrationURL: https://www.clinicaltrials.gov. Unique identifier: NCT01749254.

Project description:BackgroundOral antiplatelet therapy is the cornerstone of treatment for acute myocardial infaction (AMI). However, detailed usage data on oral antiplatelet therapy are lacking.MethodsUsing data from a nationally representative sample of patients with AMI, the detailed usage of oral antiplatelet therapy was analyzed in 40,202 consecutive eligible patients.ResultsThe proportions of patients with AMI taking loading doses of aspirin and P2Y12 inhibitors were relatively low (62.2% and 63.6%, respectively), whereas approximately 90% of patients received maintenance doses of aspirin, P2Y12 inhibitors, and dual antiplatelet therapy. The proportions of patients taking loading doses of aspirin and P2Y12 inhibitors gradually decreased with age. Male sex, an educational level of at least college, an interval from onset to treatment of < 24 h, and primary PCI use were associated with a higher proportion of patients taking a loading dose of antiplatelet therapy, whereas those receiving conservative treatment had a lower rate of antiplatelet use (all P < 0.05). The proportion of patients taking loading doses of aspirin was highest in the western region, and that of patients taking loading doses of P2Y12 inhibitors was highest in the eastern region (P < 0.05). In addition, 76.7% of patients with ST-elevation MI and 91% of patients with non-ST-elevation MI received 300-mg loading dose of clopidogrel.ConclusionsThe proportion of patients with AMI receiving loading doses of aspirin and P2Y12 inhibitors during hospitalization was relatively low, and this rate was affected by many factors, such as age, sex, educational level, region of residence, and the interval from onset to treatment. The underutilization of guideline-based P2Y12 inhibitors was also problematic. Hence, quality improvement initiatives are needed to enhance adherence to guidelines to improve consistent use of oral antiplatelet therapy. Trial registration The Chinese Acute Myocardial Infarction Registry; Trial registration number: ChiCTR-ONC-12002636; Registered 31 October 2012; http://www.chictr.org.cn/showproj.aspx?proj=6916.

Project description:Objective Although the importance of evidence-based optimal medical therapy (OMT) after acute myocardial infarction (AMI) has been recognized, the prescription rate of OMT is not sufficiently high in real-word clinical settings. The purpose of this study was to identify the clinical characteristics of AMI patients who did not receive OMT. Methods The present study was a retrospective study. OMT was defined as the combination of antiplatelet therapy, angiotensin-converting enzyme (ACE) inhibitors/angiotensin II receptor blockers (ARBs), beta-blockers, and statins at the time of hospital discharge. Non-OMT was defined as the lack of either antiplatelet therapy, ACE inhibitors/ARBs, beta-blockers, or statins. Results A total of 457 AMI patients were included as the final study population, and 98 patients (22.4%) lacked at least 1 OMT medication. The prescription rates of antiplatelet therapy, ACE inhibitors/ARBs, beta-blockers, and statins were 98.7%, 87.5%, 90.4%, and 96.7%, respectively. In the multivariate logistic regression analysis, age [per 1-year increase: odds ratio (OR) 1.033, 95% confidence interval (CI) 1.007-1.059, p=0.014], hemodialysis (vs. no hemodialysis: OR 2.707, 95% CI 1.082-6.774, p=0.033), estimated glomerular filtration rate <30 mL/min/1.73 m2 without hemodialysis (OR 4.585, 95% CI 1.975-10.644, p<0.001), AMI caused by vasospastic angina (VSA) (vs. no VSA: OR 13.198, 95% CI 1.809-96.260, p=0.011), and asthma (vs. no asthma: OR 7.241, 95% CI 1.716-30.559, p=0.007) were significantly associated with non-OMT, whereas heart rate on admission (per 1-bpm increase: 0.987, 95% CI 0.975-0.999, p=0.033), any PCI (vs. no PCI: OR 0.156, 95% CI 0.066-0.373, p<0.001), and ST-elevation myocardial infarction (STEMI) (vs. NSTEMI: OR 0.384, 95% CI 0.218-0.675, p=0.001) were inversely associated with non-OMT. Conclusion An advanced age, VSA, bradycardia, asthma, impaired renal function, non-PCI revascularization, and non-ST-elevation myocardial infarction were significantly associated with non-OMT.