Management of No-Reflow/Slow Flow Phenomenon During PCI

Definition and Diagnosis

No-reflow is characterized by inadequate myocardial reperfusion despite successful reopening of the epicardial infarct-related artery, occurring in approximately 10-40% of patients undergoing reperfusion therapy for STEMI, according to the European Heart Journal 1, 2
The diagnosis of no-reflow is typically made when post-procedural TIMI flow is < 3, or TIMI flow is 3 but myocardial blush grade (MBG) is 0 or 1, as stated by the European Heart Journal 1
ST resolution within 4 hours of the procedure is < 70%, as reported by the European Heart Journal 1, 2

No-reflow may occur due to multiple mechanisms, including downstream microvascular embolization of thrombotic or atheromatous debris, reperfusion injury, microvascular disruption, endothelial dysfunction, inflammation, and myocardial edema, as described by the European Heart Journal and Circulation 1, 3

No-reflow has serious clinical implications, including prolonged myocardial ischemia, as stated by the European Heart Journal 2
No-reflow may result in severe arrhythmias and critical hemodynamic deterioration, according to the European Heart Journal 1
No-reflow is associated with significantly increased risk of clinical complications, as reported by the European Heart Journal 1
The principal clinical sequela of no-reflow is myonecrosis, as stated by Circulation 4, 3

The American College of Cardiology recommends intracoronary administration of vasodilators, such as adenosine, calcium channel blockers (verapamil), or nitroprusside, as the first-line treatment for no-reflow phenomenon during percutaneous coronary intervention, with a Class IIa recommendation and Level of Evidence: B, as stated by Circulation 4, 3
Verapamil can be administered in doses of 100-1000 μg in incremental doses, as reported by the European Heart Journal 5
The use of an intracoronary perfusion catheter is recommended when possible, as stated by the European Heart Journal 5
GP IIb/IIIa receptor antagonist (abciximab) has been found to improve tissue perfusion and is recommended as antithrombotic co-therapy with primary PCI, according to the European Heart Journal and Circulation 1, 2, 3
Intra-aortic balloon pump (IABP) may be helpful in cases of persistent no-reflow, as reported by the European Heart Journal 5

Aspiration thrombectomy can be used as a mechanical strategy to prevent distal embolization, as stated by the European Heart Journal 5

Improvement in TIMI flow grade and myocardial blush grade should be assessed after treatment, as recommended by the European Heart Journal 1
Systemic hypotension, particularly with nitroprusside, should be monitored, as stated by Circulation 3
ST-segment resolution on ECG should be evaluated, as reported by the European Heart Journal 1, 2

The European Society of Cardiology endorses nitroprusside as effective and safe for no-reflow treatment, administered through the guiding catheter or preferably via an intracoronary perfusion catheter for distal delivery 6

The European Society of Cardiology provides a recommendation for intracoronary vasodilators including nitroprusside in no-reflow, based on evidence from the European Heart Journal 6

Avoid nitroprusside in patients with baseline systolic BP <90 mmHg, as recommended by the European Heart Journal and European Journal of Heart Failure 7, 8
Use extreme caution in patients with aortic stenosis who may develop marked hypotension, as noted by the European Heart Journal and European Journal of Heart Failure 7, 8

The European Society of Cardiology notes that verapamil (100-1000 mcg) and adenosine are equally viable alternatives to nitroprusside, and combination therapy with adenosine plus nitroprusside may be superior to either agent alone 6