Low Risk Non ST Elevation Myocardial Infarction With or Without Intensive Care Unit Admission

Favourable in-hospital outcome is observed in numerous patients after Non ST myocardial infarction (NSTEMI) with invasive strategy but European guidelines proposed systematic intensive care unit monitoring up to 24 h in lower risk patients (grade 1, level of evidence C). Regarding absence of prospective study supporting this strategy, we assessed the hypothesis that the lower risk NSTEMI patients identified through simple medical criteria and after coronary angiography evaluation may not require intensive care unit admission.

The incidence of serious in hospital complications after NSTEMI has dramatically decreased over the past decades mainly due to early coronary angioplasty with new generation drug eluting stents surrounded by an optimal antithrombotic treatment (1). Major in-hospital adverse events after NSTEMI became uncommon and above all appears predictable including unstable hemodynamic state, acute stent thrombosis and life threatening arrhythmia (5-7). Recent 2020 European guidelines recommended that all patients with NSTEMI should be monitored up to 24 hours or up to percutaneous coronary intervention (PCI) in the intensive care unit (ICU) and rhythm monitoring \> 24 h in patients at intermediate or high risk of cardiac arrhythmia (2). However, the usefulness of systematic ICU admission and ECG monitoring, for lower risk patients particularly when they have been stabilized with successful (PCI) has never been evaluated in a randomized study and remain controversial (8-10).

The main objective of this randomized study is to validate the feasibility and safety of a strategy without intensive care unit admission of lower risk NSTEMI patients after coronary angiography evaluation and successful PCI when required, compared to the conventional strategy using systematic ICU monitoring.

All patients admitted in our hospital for NSTEMI (initial admission of patients in ICU or directly in the cath lab) will have systematic coronary angiography evaluation and PCI when required. They will be classified as low or high risk patients related to guidelines derived criteria including results of coronary angiography evaluation. Low risk patients will be randomized in ICU admission group (control group) or general cardiology ward (GCW) group (experimental group) without ECG monitoring.

Eligibility Criteria:
Inclusion Criteria:

* Age \> or = to 18 years
* NSTEMI was defined according guidelines with chest pain with or without ECG modifications and significant troponin elevation (hs-cTn T \*≥ 52 ng/l) or significant variation \> 10 ng/l between 2 dosages between 1 or 3 hours interval) \* Elecsys Roche
* Coronary angiography mandatory \< 24 h after first troponin assay according to 2020 NSTEMI guidelines and PCI if required
* Low risk NSTEMI defined with (all necessary):

  * Age\<85 years
  * Optimal antithrombotic therapy using new generation P2Y12 inhibitors (ticagrelor or prasugrel) or clopidogrel and aspirin with preloading at the latest before PCI
  * Success of PCI (one or 2 arteries)
  * Low risk of severe arrhythmia (ESC criteria) if none of the following criteria: haemodynamically unstable, major arrhythmias, LVEF \<40%, failed reperfusion, additional critical coronary stenosis of major vessels, complications related to percutaneous revascularization,
  * No major comorbidities requiring specific care
  * Success of PCI without any event within 30 minutes after the procedure
  * Low bleeding risk (ESC criteria) according to CRUSADE criteria validated in NSTEMI

Exclusion Criteria:

* STEMI
* Unstable angina troponin \<5ng/l\* or \<14ng/l with variation \<4ng/l between 2 dosages )\* Elecsys Roche
* High risk NSTEMI if one low risk criteria defined above is absent
* Patient with acute coronary syndromes (ACS) requiring transfer to resuscitation unit and not to intensive care unit for any reason
* Coronary angiography not performed or performed \> 24 h after first troponin assay in ICU
* Pregnant or breastfeeding woman
* Patient unable or refusing to sign inform consent
* Patient without health care insurance
* Patient under legal guardianship