- Design
- Systematic review and meta-analysis of 43 observational studies
- Population
- 27,405 patients with STEMI undergoing primary PCI
- Primary outcome
- Factors associated with slow flow or no-reflow
- Effect
- 5,631 events (about 21%); adjusted associations for age, hypertension, diabetes, Killip ≥II and thrombus burden; low to very low certainty
A meta-analysis of 43 observational studies covering 27,405 patients with STEMI treated by primary PCI, of whom 5,631 developed slow flow or no-reflow, mapped the factors associated with it.
In analyses limited to adjusted estimates, the associations that held were older age, hypertension, diabetes, Killip class II or higher, and high thrombus burden. Cruder pooled estimates also linked poor baseline TIMI flow, longer stent length, thrombus aspiration and direct stenting, but several prediction intervals crossed the null.
Risk of bias was mostly some or high concern and certainty low or very low, and the authors describe it as a map rather than a causal list or a bedside score. The procedural associations, in particular, may reflect which patients were chosen for those techniques.
The practical use is anticipation: a diabetic, older patient in heart failure with a large thrombus load is the one in whom to have no-reflow pharmacology ready before the wire crosses.
- Anticipate no-reflow in older, diabetic or hypertensive STEMI patients with Killip class II or higher
- Treat a high angiographic thrombus burden as a warning sign before stenting
- Have intracoronary vasodilators prepared in high-risk cases
- Do not change stenting or aspiration technique on these associations alone
Why it matters
Most no-reflow risk is visible before the procedure starts.
Don't overread it
These are observational associations of low or very low certainty; they do not show that changing technique prevents no-reflow.
The statistics, in plain English
A prediction interval that crosses the null means a future study in a different setting might find no association at all, even if the average across studies points one way.
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