Early or Selective Invasive Strategy in Patients with Non-ST-segment Elevation Acute Coronary Syndrome According to the Risk Factors at Presentation? An Outcome Study

Aims: Patients with acute coronary syndrome without ST segment elevation are a heterogeneous group with respect to the risk of having a major adverse cardiac event (MACE). History of diabetes mellitus (DM), chronic kidney disease (CKD) and elevated GRACE risk score are all factors defining a higher risk of MACE. We aimed to compare the outcome of patients with early vs selective invasive strategy according to the risk factors at presentation.

Methodology: We enrolled 178 patients with unstable angina or non-ST elevation myocardial infarction (UA/NSTEMI), 52 (29.2%) had DM, 32 (19.7%)-CKD, defined when MDRD measured glomerular filtration rate (GFR) was <60ml/min/1.73m2 and 28 (15.7%) had GRACE≥140. The study had two arms: an early invasive strategy one (coronary arteriography and percutaneous coronary intervention within 24 hours after admission), and a selective invasive strategy arm (medical stabilization, with coronary arteriography required only in case of angina recurrence and/or evidence of inducible myocardial ischemia). Follow-up was 22.8±14 months.

Results: For the whole group MACE occurred less often and the event free period was longer in the early invasive strategy group compared to selective invasive one (p=0.001). Early invasive strategy in diabetic patients, those with CKD and with GRACE ≥140 was associated with a reduced MACE rate (p=0.008, 0.016 and 0.006, respectively) and longer time to MACE occurrence compared with the selective invasive strategy.

When we evaluated separately non-diabetics, patients with normal renal function and those with GRACE <140 we found no significant difference in MACE rate between the patients allocated to early invasive strategy and those assigned to selective invasive strategy. Early invasive strategy, however, showed some advantage over the selective one also in the subgroup analysis-the time to occurrence of MACE was prolonged in patients with lower risk at presentation.

Conclusions: Early invasive strategy in UA/NSTEMI is associated with a reduced MACE rate and longer event-free period compared with selective invasive strategy. This benefit is clearly evident in higher risk subsets (patients with DM, CKD and GRACE ≥140).