Assessing Microvascular Resistance Via IMR To Predict Cumulative Outcome in STEMI Patients Undergoing Primary PCI (AMICRO)

Assessing Microvascular Resistance Via IMR To Predict Cumulative Outcome in STEMI Patients Undergoing Primary PCI (AMICRO)

The purpose of this study is to assess whether the Index of Microcirculatory Resistance (IMR) can be considered a prognostic predictor for the occurrence of events at one year of follow up after primary Percutaneous Coronary Intervention (PCI) in ST-Elevation Myocardial Infarction (STEMI) patients.

Any correlation between IMR and the short and medium term outcomes, defined as cardiovascular death, re-Myocardial Infarct (MI), re-hospitalization for Heart Failure (HF), resuscitation or Implantable Cardioverter Defibrillator (ICD) appropriate shock, will be assessed in the study.

Study Overview

• Status: Completed
• Conditions: STEMI; Multi Vessel Coronary Artery Disease
• Intervention / Treatment: Device: PressureWire Certus guidewire

Detailed Description

Prospective, multicentre study designed to evaluate IMR ability to predict events occurrence, defined as Cardiovascular death, re-MI, re-hospitalization for HF, resuscitation or ICD appropriate shock, during a 1 year follow-up period.

All participants will have the culprit lesion treated following clinical practice and guidelines; Fractional Flow Reserve (FFR) and IMR will be measured after the primary PCI procedure to evaluate treatment success and myocardial viability. Non-culprit lesions will be functionally evaluated through FFR index and will be treated if FFR will show functional stenosis. FFR and IMR will be measured to evaluate treatment success and myocardial viability. Patients will be followed-up at 1m, 6m and 1y periods.

• Study Type: Interventional
• Enrollment (Actual): 242
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Italy
  • La Spezia, Italy, 19100
    • Ospedale Sant'Andrea
  • Siena, Italy, 53100
    • Policlinico Le Scotte
  • Agrigento
    • Sciacca, Agrigento, Italy, 92019
      • Ospedale Giovanni Paolo II
  • BA
    • Acquaviva delle Fonti, BA, Italy, 70021
      • Ospedale Generale Regionale "F. Miulli"
  • FI
    • Firenze, FI, Italy, 50134
      • Azienda Ospedaliera Universitaria Careggi
  • GE
    • Genova, GE, Italy, 16149
      • Azienda Ospedaliera Villa Scassi
  • MS
    • Massa, MS, Italy, 54100
      • Fondazione Toscana G.Monasterio - Ospedale del Cuore
  • PD
    • Padova, PD, Italy, 35128
      • Azienda Ospedaliera di Padova
  • PU
    • Pesaro, PU, Italy, 61121
      • Azienda Ospedaliera Ospedali Riuniti Marche Nord
  • PV
    • Pavia, PV, Italy, 27100
      • Fondazione IRCCS Policlinico S.Matteo
  • RE
    • Reggio Emilia, RE, Italy, 43123
      • Arcispedale Santa Maria Nuova
  • Treviso
    • Castelfranco Veneto, Treviso, Italy, 31033
      • Ospedale di Castelfranco Veneto
    • Conegliano, Treviso, Italy, 31015
      • Presidio Ospedaliero di Conegliano
  • VA
    • Varese, VA, Italy, 21100
      • Ospedale di Circolo Fondazione Macchi

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Patient of legal age in hosting country able and willing to provide informed consent form
2. Hospital admission either within 12 h of symptom onset or between 12 and 24 h after onset with evidence of continuing ischemia
3. Electrocardiographic ST-segment elevation ≥1 mm in two or more contiguous ECG leads, or with a left bundle-branch block (LBBB)
4. Multivessel diseased patients with lesions in the proximal 2/3 part of the vessels
5. Culprit Lesion EyeBall (EB) identified during evaluation of basal angiography
6. Presence of at least one non-culprit lesion >50% EB detected in the basal angiography and eligible for PCI for which the operators decision is to perform a staged pre-discharge angioplasty procedure

Exclusion Criteria:

1. Patients who cannot give informed consent
2. A life expectancy of less than 1 year
3. Patients who are pregnant or nursing
4. Contra-indication to angiography
5. Allergy/intolerance to Adenosine
6. Contra-indication/Allergy/Intolerance to contrast media or to medical therapy foreseen for PCI
7. Documented allergy to Adenosine diphosphate (ADP) inhibitors (aspirin and clopidogrel)
8. New infarct on the same area of a previous infarct
9. Critical non treatable Lesion EB>70% downstream of the culprit lesion
10. Absence of non-culprit lesion/s
11. Patient with hemodynamic instability not controllable with medical therapy and/or need intra aortic balloon pump implantation (IABP)
12. Prior Coronary Artery Bypass Graft (CABG) or indication for CABG
13. Patients with Left Main (LM) coronary artery disease requiring revascularization

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: IMR evaluation; Assessment of IMR index in coronaries through PressureWire Certus guidewire	Device: PressureWire Certus guidewire; Assessment of IMR index in coronaries through PressureWire Certus guidewire

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Composite of: Cardiovascular Death*, Re-myocardial Infarct, Re-hospitalization for Heart Failure (HF) and Congestive Heart Failure (CHF), Resuscitation or ICD Appropriate Shock.	Composite of: cardiovascular death*, re-myocardial infarct, re-hospitalization for heart failure (HF) and Congestive Heart Failure (CHF), resuscitation or ICD appropriate shocK, at 1 year. * = timing of mortality evaluation: once culprit lesion has been evaluated through IMR Composite endpoint was evaluated as time to first event, whichever individual component occurred first.	1 year

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
New Congestive Heart Failure (CHF) During Index Hospitalization	Count of participants with a new CHF during index hospitalization. Hospital stay expected average = 5-10 days	At the end of hospital stay
Left Ventricular (LV) Remodeling	Left Ventricular (LV) remodeling at 1 year; improvement of Ejection Fraction %(EF) assessed by TTE. A TTE evaluation has been done both at discharge and at 1-year fup.	1 year
Left Ventricular (LV) Remodeling	Left Ventricular (LV) remodeling at 1 year; improvement of Left Ventricular End Systole Volume (LVESV) and Left Ventricular End Diastole Volume (LVEDV) assessed by TTE. A TTE evaluation has been done both at discharge and at 1-year fup.	1 year
Left Ventricular (LV) Remodeling	Left Ventricular (LV) remodeling at 1 year; improvement of Left Ventricular End Diastole Diameter (LVEDD) and Left Ventricular End Systole Diameter (LVESD) assessed by TTE. A TTE evaluation has been done both at discharge and at 1-year fup.	1 year
Left Ventricular (LV) Remodeling	Left Ventricular (LV) remodeling at 1 year; improvement of 16 segments Wall Motion Score Index (WMSI) assessed by TTE. A TTE evaluation has been done both at discharge and at 1-year fup. 16WMSI = 1 is considered normokinetic; 16WMSI = 1,5 is considered mild hypokinesia; 16WMSI = 2 is considered hypokinesia; 16WMSI = 2,5 is considered severe hypokinesia; 16WMSI = 3 is considered akinetic. Scale range: from 1 to 3	1 year
Left Ventricular (LV) Remodeling - Mitral Insufficiency	Left Ventricular (LV) remodeling at 1 year; improvement of mitral insufficiency (MI) values assessed by TTE. A TTE evalutation has been done both at discharge and at 1-year fup. Each row reports the number of participants that have that specific grade of mitral insufficiency. Grade = 0 indicates no MI; grade = 1 indicates mild MI; grade = 2 indicates moderate MI; grade = 3 indicates severe MI	1 year
Need for New Revascularization	Incidence of new revascularizations at 1 year	1 year
Stent Thrombosis	Incidence of stent thrombosis at 1 year	1 year
Evaluation of a Better Cut-off of IMR Index Based on Primary Endpoints Events	Evaluation of a better cut-off of IMR index based on primary endpoints events. Table below reports the values of ROC curve.	1 year
Evaluation of Possible Events Predictors	Results of logistic regression model; differences were considered statistically significant when p<0,05.	1 year

Collaborators and Investigators

• Sponsor: Abbott Medical Devices
• Investigators: Study Chair: Massimo Fineschi, MD, Policlinico Le Scotte, Siena; Study Chair: Marco Valgimigli, MD

Study record dates

Study Major Dates

• Study Start: June 1, 2013
• Primary Completion (Actual): February 1, 2018
• Study Completion (Actual): February 1, 2018

Study Registration Dates

• First Submitted: January 30, 2014
• First Submitted That Met QC Criteria: December 19, 2014
• First Posted (Estimated): December 25, 2014

Study Record Updates

• Last Update Posted (Actual): August 8, 2025
• Last Update Submitted That Met QC Criteria: July 23, 2025
• Last Verified: July 1, 2025

More Information

Terms related to this study

• Keywords: STEMI; FFR; IMR; microcirculatory
• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Pathologic Processes; Heart Diseases; Infarction; Necrosis; Arteriosclerosis; Arterial Occlusive Diseases; Coronary Disease; Myocardial Ischemia; Myocardial Infarction; Ischemia; ST Elevation Myocardial Infarction; Coronary Artery Disease
• Other Study ID Numbers: CV-12-018-IT-PW