Feasibility of the Manchester Acute Coronary Syndromes (MACS) decision rule to safely reduce unnecessary hospital admissions: a pilot randomised controlled trial
Key result
MACS rule increases safe rapid ED discharges ~5-fold vs standard care without missing major events.
- adjusted OR 5.45
- 95% CI 1.73 to 17.11
- P=0.004
- n=131
Why the study?
Observational studies suggested the MACS decision rule can effectively rule out and rule in ACS after a single blood test, but feasibility of a large trial was unknown.
Does care guided by the MACS decision rule safely increase successful ED discharges within 4 hours in patients with suspected cardiac chest pain?
Population
131 patients presenting to two EDs with suspected cardiac chest pain
Comparison
Care guided by MACS decision rule vs standard care
Design
Pilot randomised controlled trial
Follow-up
30 days
Authors
Discussion
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Member takes
Implication
Supports MACS rule adoption to safely increase early ED discharges; extends randomized evidence for decision aids in chest pain triage.
Key Points
- To evaluate the feasibility of conducting a definitive, large-scale randomized controlled trial of the Manchester Acute Coronary Syndromes (MACS) decision rule to safely reduce unnecessary hospital admissions.
- Conducted a pilot randomized trial across two emergency departments involving 131 patients presenting with suspected cardiac chest pain, assigned to either MACS decision rule guidance (n=66) or standard care (n=65) with 30-day follow-up (ISRCTN 86818215).
- Evaluated feasibility endpoints alongside the primary efficacy outcome: safe discharge within 4 hours without missed acute myocardial infarction (AMI) or 30-day major adverse cardiac events (MACE: death, AMI, or coronary revascularisation).
- A significantly greater proportion of patients managed with the MACS rule met the primary outcome of safe discharge within 4 hours compared to standard care (26% vs 8%, adjusted OR 5.45, 95% CI 1.73 to 17.11, p=0.004).
- No patients discharged within 4 hours developed acute myocardial infarction or incident MACE within 30 days (0.0%, 95% CI 0.0% to 20.0% in the intervention group).
- Trial feasibility was supported by high recruitment efficiency (131 of 138 eligible patients randomized, 95%) and 100% 30-day follow-up completion with no missing primary endpoint data.
Study Design
Type
RCT (n=131)
Blinding
Open-label
Randomization
1:1 central, internet-based, stratified by trial centre and MACS rule risk group
Multicenter
Yes
Structured PICO
Does care guided by the MACS decision rule safely increase successful ED discharges within 4 hours in patients with suspected cardiac chest pain?
P
Population
131 adults presenting to the emergency department with suspected acute coronary syndromes, followed for 30 days to assess the feasibility and safety of early discharge.
I
Intervention
Care guided by the Manchester Acute Coronary Syndromes (MACS) decision rule
C
Comparator
Standard care
O
Outcome
Successful discharge from the ED, defined as a decision to discharge within 4 hours of arrival providing that the patient did not have a missed acute myocardial infarction (AMI) or develop a major adverse cardiac event (MACE: death, AMI or coronary revascularisation) within 30 dayscomposite
Main Result
Odds Ratio: 5.45 (95% CI 1.73–17.11)
Absolute Event Rate: 26% vs 8%
p-value: p=0.004
The MACS decision rule is feasible to implement and safely increases the proportion of patients with suspected cardiac chest pain discharged from the ED within 4 hours.
Limitations
- Small sample size as a pilot trial, lacking statistical power to definitively assess safety outcomes (incidence of MACE)
- The MACS rule has only been validated with one specific high-sensitivity troponin T assay
- The rule incorporates H-FABP, a biomarker not currently used in routine clinical practice
- Suboptimal recruitment rate at one of the two trial sites
- Pilot trial (small sample size, not fully powered)
Cite This Study
Body et al. (2017) conducted an RCT in Suspected acute coronary syndromes (n=131). Manchester Acute Coronary Syndromes (MACS) decision rule vs. Standard care was evaluated on Successful discharge from the ED within 4 hours without missed acute myocardial infarction or incident major adverse cardiac event within 30 days (adjusted OR 5.45, 95% CI 1.73 to 17.11, p=0.004). Care guided by the MACS decision rule significantly increased the proportion of patients successfully discharged within 4 hours without missed AMI or incident MACE at 30 days compared to standard care (26% vs 8%, adjusted OR 5.45).