A total of 100 patients with ST-elevation myocardial infarction (STEMI) presenting
slow-flow after primary-percutaneous coronary intervention (PPCI) will be randomized to
pharmacologic treatment with hyperemic drugs versus flow-mediated hyperemia.

Treatment of Slow-flow After Primary Percutaneous Coronary Intervention With Flow-mediated Hyperemia

Coronary Microvascular Disease

Myocardial Infarction

Slow-flow phenomena is observed around 15% of patients undergoing PPCI and has been
associated with poor prognosis. Hyperemic drugs, such as nitroprussiate and adenosine,
have not yet demonstrated to reduce the infarct size and prognosis in patients with slow
flow. Controlled flow-mediated hyperemia using a dedicated catheter for intracoronary
saline infusion has been shown to stimulate microcirculatory vasodilatation in stable
patients similarly as hyperemic drugs.

The aims of the study are to compare the absolute microcirculatory resistance of the
infarct-related artery presenting with slow flow after PPCI, as assessed by intracoronary
thermo-dilution, treated with standard pharmacologic hyperemia versus flow-mediated
hyperemia; and to compare the angiographic TIMI frame count after treatment of slow flow
phenomena with the two investigated strategies.

Drug-mediated hyperemia

Flow-mediated hyperemia

Cine-fluoroscopic recording of the infarct-related artery (IRA) at 30 frames/second and
off-line core-laboratory assessment of the number of cineframes needed for dye to reach
standardized distal landmarks is the coprimary endpoint. Long TIMI frame counts are
indicative of slow coronary flow. Previous studies showed TIMI frame counts of 30 (SD 12)
after nitroprussiate in slow flow STEMI patients. The present study is powered to assess
25 percent difference between study groups (80 percent power and 5 percent alfa error).

MMR is assessed by intracoronary thermodilution with a dedicated pressure wire and
microcatheter (RayFlow, Hexacath) during saline infusion at 20 ml/min. MMR is measured
offline by the core-laboratory at 20 seconds of the saline infusion in the standard
medical treatment group and at 2 minutes and 20 seconds in the experimental group.
According to previous studies, MMR was 537 Wood units (SD 289). The present study is
powered to assess 30 percent difference between study groups after study intervention (80
percent power and 5 percent alfa error).

Experimental treatment with saline infusion via microcatheter is performed continuously
recording the pressure and temperature values of the culprit artery. Off-line
core-laboratory assessment of the MMR will be performed at 20 seconds and at 2 minutes of
the saline infusion.

Absolute coronary flow is performed simultaneously with the MMR. This value shows the
coronary blood flow of the culprit artery during maximal hyperemia.

Patients presenting with slow flow after PPCI undergo to at least 200 mcg of
intracoronary nitroprussiate or 500 mcg of intracoronary adenosine during 2 minutes

Patients presenting with slow flow after PPCI undergo to controlled saline intracoronary
infusion by a dedicated microcatheter (RayFlow) at 20 ml/min during 2 minutes

Treatment of Slow-flow After Primary Percutaneous Coronary Intervention With Flow-mediated Hyperemia

About this trial

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Placebo

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