What is the clinical evidence from this study?

Study design: Meta-Analysis. Population: Non-ST-elevation acute coronary syndrome (NSTE-ACS) (n=12331). Intervention: Invasive strategy vs. Conservative strategy. Primary outcome: Major adverse cardiovascular event (MACE) at ≤6 months (RR 0.83, 95% CI 0.68-1.01, p=0.067).

September 8, 2023Open Access

Comprehensive evaluation of time-varied outcomes for invasive and conservative strategies in patients with NSTE-ACS: a meta-analysis of randomized controlled trials

Key Result

An invasive strategy did not significantly reduce major adverse cardiovascular events at ≤6 months compared to a conservative strategy in patients with NSTE-ACS (RR 0.83).

Study Design

Type

Meta-Analysis (n=12,331)

Randomization

Randomized

Multicenter

Yes

Structured PICO

Does an invasive strategy reduce major adverse cardiovascular events and other time-varied outcomes in patients with NSTE-ACS compared to a conservative strategy?

Population

12,331 patients with non-ST-elevation acute coronary syndrome (NSTE-ACS) pooled from 17 randomized controlled trials

Intervention

Invasive strategy (early or routine invasive approach with early coronary angiography followed by revascularization without first undergoing preliminary non-invasive stress testing or experiencing treatment failure with optimal medical care)

Comparator

Conservative strategy (optimal medical therapy and subsequent invasive evaluation only for patients with residual symptoms or objective evidence of myocardial ischemia)

Outcome

Major adverse cardiovascular event (MACE) at varied follow-up periods (≤6 months, 1 year, 2 years, 3 years, 5 years, and ≥10 years)composite

An invasive strategy for NSTE-ACS reduces early MI and rehospitalizations but increases early bleeding, without providing significant long-term benefits in MACE or mortality compared to a conservative strategy.

Main Result

Effect estimate: RR 0.83 (95% CI 0.68-1.01)

p-value: p=0.067

Limitations

Individual patient data were not available, leading to insufficiency in the subgroup analysis stratified by high-risk features
The enrollment time of the 17 RCTs span almost 30 years from 1989 to 2017, during which major achievements in interventional and medical management have been made
The sample sizes ranged from 52 to 2,220 and may have contributed to high heterogeneity
Available evidence is based on relatively old RCTs

Abstract

Background: Results from randomized controlled trials (RCTs) and meta-analyses comparing invasive and conservative strategies in patients with non-ST-elevation acute coronary syndrome (NSTE-ACS) are highly debatable. We systematically evaluate the efficacy of invasive and conservative strategies in NSTE-ACS based on time-varied outcomes. Methods: The RCTs for the invasive versus conservative strategies were identified by searching PubMed, Cochrane Central Register of Controlled Trials, Embase, and ClinicalTrials. gov. Trial data for studies with a minimum follow-up time of 30 days were included. We categorized the follow-up time into six varied periods, namely, ≤6 months, 1 year, 2 years, 3 years, 5 years, and ≥10 years. The time-varied outcomes were major adverse cardiovascular event (MACE), death, myocardial infarction (MI), rehospitalization, cardiovascular death, bleeding, in-hospital death, and in-hospital bleeding. Risk ratios (RRs) and 95% confidence intervals (Cis) were calculated. The random effects model was used. Results: This meta-analysis included 30 articles of 17 RCTs involving 12, 331 participants. We found that the invasive strategy did not provide appreciable benefits for NSTE-ACS in terms of MACE, death, and cardiovascular death at all time points compared with the conservative strategy. Although the risk of MI was reduced within 6 months (RR 0. 80, 95% CI 0. 68-0. 94) for the invasive strategy, no significant differences were observed in other periods. The invasive strategy reduced the rehospitalization rate within 6 months (RR 0. 69, 95% CI 0. 52-0. 90), 1 year (RR 0. 73, 95% CI 0. 63-0. 86), and 2 years (RR 0. 77, 95% CI 0. 60-1. 00). Of note, an increased risk of bleeding (RR 1. 80, 95% CI 1. 28-2. 54) and in-hospital bleeding (RR 2. 17, 95% CI 1. 52-3. 10) was observed for the invasive strategy within 6 months. In subgroups stratified by high-risk features, the invasive strategy decreased MACE for patients aged ≥65 years within 6 months (RR 0. 68, 95% CI 0. 58-0. 78) and 1 year (RR 0. 75, 95% CI 0. 62-0. 91) and showed benefits for men within 6 months (RR 0. 71, 95% CI 0. 55-0. 92). In other subgroups stratified according to diabetes, ST-segment deviation, and troponin levels, no significant differences were observed between the two strategies. Conclusions: An invasive strategy is superior to a conservative strategy in reducing early events for MI and rehospitalizations, but the invasive strategy did not improve the prognosis in long-term outcomes for patients with NSTE-ACS. Systematic Review Registration: https: //www. crd. york. ac. uk/prospero/displayᵣecord. php? ID=CRD42021289579, identifier PROSPERO 2021 CRD42021289579.

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