Design: international, randomised, open-label trial
Population: 1823 patients with STEMI and multivessel disease after successful culprit treatment; median age 66, 24% women
Primary outcome: composite of death, myocardial infarction, stroke or TIA, or ischaemia-driven revascularisation at median 17.9 months
Effect: 8.9% vs 13.7%, hazard ratio 0.62 (95% CI 0.47-0.83), P<0.001

In an international randomised trial, 1823 patients with ST-elevation myocardial infarction and multivessel disease whose culprit lesion had been successfully treated were assigned to complete revascularisation guided either by functional coronary angiography or by conventional angiography. Median age was 66, and 24% were women. Over a median 17.9 months, the composite of death from any cause, myocardial infarction, stroke or transient ischaemic attack, and ischaemia-driven revascularisation occurred in 81 of 913 (8.9%) in the physiology-guided group against 125 of 910 (13.7%) with angiographic guidance: hazard ratio 0.62 (95% CI 0.47 to 0.83), P<0.001.

The safety result is what makes this unusual. Strategies that add assessment usually buy their benefit with more contrast, more instrumentation and more bleeding. Here the safety composite of contrast-associated acute kidney injury or major bleeding went the same way as efficacy, 4.6% against 7.1%, hazard ratio 0.63 (95% CI 0.43 to 0.93). The most likely explanation is that physiology deferred lesions that would otherwise have been stented - fewer procedures, less contrast, less bleeding - rather than any protective effect of the assessment itself.

Guidelines already recommend complete revascularisation in this population; the open question has been how to choose which non-culprit lesions to treat. This is a direct answer, in a trial large enough to act on. For Indian laboratories the barrier is cost and availability of pressure wires rather than the principle, and the deferral effect matters here too: fewer stents implanted is a cost argument as well as a clinical one.

Where a pressure wire is available, use physiology rather than appearance to select non-culprit lesions for staged treatment.
Expect the strategy to result in fewer lesions treated, not more - that is where the safety benefit comes from.
Do not extend this to the culprit lesion or to the acute phase; the trial started after successful culprit treatment.
Factor the deferred stents into the cost case when arguing for wire availability.
Re-audit local staged PCI rates after adopting it; a rate that does not fall suggests physiology is not changing decisions.

Why it matters

It settles which non-culprit lesions to treat with something other than the operator's eye, and it does so without the usual trade-off of more contrast and more bleeding.

The statistics, in plain English

A hazard ratio of 0.62 with a confidence interval of 0.47 to 0.83 means the benefit is unlikely to be chance: the whole interval sits below 1.0, and even the least favourable end is a 17% reduction. In absolute terms the difference is 13.7% to 8.9%, about 21 patients treated this way to avoid one event. The safety interval (0.43 to 0.93) reaches closer to 1.0, so the harm reduction is real but less precisely estimated than the efficacy result.