Comparison of early invasive and conservative strategies in patients with unstable coronary syndromes

Higher Long-Term Mortality in Patients with Non-ST-Elevation Myocardial Infarction than ST-Elevation Myocardial Infarction after Discharge

PURPOSE

This study aimed to compare mortality rates after discharge between the patients with non-ST-elevation myocardial infarction (NSTEMI) and those with ST-elevation myocardial infarction (STEMI), and identify each mortality risk factors in these two types of myocardial infarction.

MATERIALS AND METHODS

Between 2011 and 2015, 13105 consecutive patients were enrolled in the Korea Acute Myocardial Infarction-National Institute of Health registry (KAMIR-NIH); 12271 patients with acute myocardial infarction met the inclusion criteria and were further stratified into the STEMI (n=5828) and NSTEMI (n=6443) groups. The occurrence of mortality and cardiac mortality at 3 years were compared between groups, and the factors associated with mortality for NSTEMI and STEMI were evaluated.

RESULTS

The comparison between these two groups and long-term follow-up outcomes showed that the cumulative rates of all-cause and cardiac mortality were higher in the NSTEMI group than in the STEMI group [all-cause mortality: 10.9% vs. 5.8%; hazards ratio (HR), 0.464; 95% confidence interval (CI), 0.359-0.600, p<0.001; cardiac mortality: 6.6% vs. 3.5%, HR, 0.474; 95% CI, 0.344-0.654, p<0.001, respectively). In the NSTEMI group, low left ventricular ejection fraction (LVEF; <40%), no percutaneous coronary intervention (PCI), old age (≥65 years), and low hemoglobin level (<12 g/dL) were identified as risk factors for 3-year mortality. In the STEMI group, old age, low glomerular filtration rate (<60 mL/min/1.73 m²), low LVEF, high heart rate (>100 beats/min), no PCI, and low hemoglobin level were identified as the risk factors for 3-year mortality.

CONCLUSION

The NSTEMI group had higher mortality compared to the STEMI group during the 3-year clinical follow-up after discharge. Low LVEF and no PCI were the main risk factors for mortality in the NSTEMI group. In contrast, old age and renal dysfunction were the risk factors for long-term mortality in the STEMI group.

How should patients with unstable angina and non-ST-segment elevation myocardial infarction be managed? A meta-analysis of randomized trials

PURPOSE

Patients with unstable angina or non-ST-segment elevation myocardial infarction (MI) may be managed with either an "invasive" or "conservative" strategy. It is unclear which of these strategies is superior.

METHODS

We identified studies with MEDLINE and EMBASE searches (1966-September 2003) and by reviewing reference lists. Studies were included if they were randomized controlled trials comparing management strategies for patients in the early post-unstable angina/non-ST-segment elevation MI period and had follow-up data for at least 3 months.

RESULTS

Seven trials that randomized a total of 9212 patients were included. The pooled odds ratio (OR) for all-cause mortality was 0.96 (95% confidence interval [CI]: 0.72 to 1.27). The occurrence of fatal or nonfatal re-infarction was reduced with an invasive strategy (OR 0.73; 95% CI: 0.61 to 0.88) as was readmission to hospital (OR 0.67; 95% CI: 0.48 to 0.94). The endpoints of nonfatal MI and the composite of death or nonfatal MI showed nonsignificant trends favoring an invasive strategy. Trials that included a higher proportion of patients with ST-segment depression on admission and trials in which a larger proportion of patients underwent revascularization showed a greater magnitude of benefit for an invasive strategy.

CONCLUSION

For patients with unstable angina/non-ST-segment elevation MI, an invasive strategy reduces rates of fatal or nonfatal re-infarction and hospital readmission, but not all-cause mortality, when compared with a noninvasive strategy. These results suggest that an invasive management strategy should be considered for all patients with unstable angina/non-ST-segment elevation MI and perhaps in particular those with ST-segment depression.

Interventional versus conservative treatment for patients with unstable angina or non-ST-elevation myocardial infarction: the British Heart Foundation RITA 3 randomised trial. Randomized Intervention Trial of unstable Angina

BACKGROUND

Current guidelines suggest that, for patients at moderate risk of death from unstable coronary-artery disease, either an interventional strategy (angiography followed by revascularisation) or a conservative strategy (ischaemia-driven or symptom-driven angiography) is appropriate. We aimed to test the hypothesis that an interventional strategy is better than a conservative strategy in such patients.

METHODS

We did a randomised multicentre trial of 1810 patients with non-ST-elevation acute coronary syndromes (mean age 62 years, 38% women). Patients were assigned an early intervention or conservative strategy. The antithrombin agent in both groups was enoxaparin. The co-primary endpoints were a combined rate of death, non-fatal myocardial infarction, or refractory angina at 4 months; and a combined rate of death or non-fatal myocardial infarction at 1 year. Analysis was by intention to treat.

FINDINGS

At 4 months, 86 (9.6%) of 895 patients in the intervention group had died or had a myocardial infarction or refractory angina, compared with 133 (14.5%) of 915 patients in the conservative group (risk ratio 0.66, 95% CI 0.51-0.85, p=0.001). This difference was mainly due to a halving of refractory angina in the intervention group. Death or myocardial infarction was similar in both treatment groups at 1 year (68 [7.6%] vs 76 [8.3%], respectively; risk ratio 0.91, 95% CI 0.67-1.25, p=0.58). Symptoms of angina were improved and use of antianginal medications significantly reduced with the interventional strategy (p<0.0001).

INTERPRETATION

In patients presenting with unstable coronary-artery disease, an interventional strategy is preferable to a conservative strategy, mainly because of the halving of refractory or severe angina, and with no increased risk of death or myocardial infarction.