Geographic heterogeneity in outcomes of intravascular ultrasound-guided vs angiography-guided percutaneous coronary...

Intravascular ultrasound (IVUS)-guided percutaneous coronary intervention (PCI) has improved outcomes in randomized trials, yet some recent European trials reported neutral results despite positive findings from East Asian studies. This study assessed whether benefit was consistent across settings.

Randomized trials comparing IVUS-guided with angiography-guided drug-eluting stent PCI were systematically reviewed and meta-analysed. Pooled risk ratios (RRs) used restricted maximum likelihood random-effects models with Hartung-Knapp-Sidik-Jonkman adjustment. Geographic effect modification was pre-specified as the primary hypothesis, and the interaction test for cardiac death was the primary analysis.

Seventeen trials (14 033 patients; 10 East Asian [10 155], 7 non-Asian [3878]) were included. The pooled RR for cardiac death was.71 (95% confidence interval [CI] .53-.94, P = .022), with a significant geographic interaction: East Asian RR.56 (.46-.69) vs non-Asian RR 1.23 (.85-1.76; interaction P < .001). Treatment effects diverged for target-vessel myocardial infarction (TV-MI; interaction P = .011), target-vessel revascularization (TVR; interaction P = .004), and major adverse cardiovascular events (MACE; interaction P = .040). IVUS guidance reduced definite stent thrombosis (RR .39, 95% CI .19-.79; interaction P = .433). All-cause death was similar (RR .89, 95% CI .76-1.04).

Considering all studies, IVUS-guided PCI reduced cardiac death, TV-MI, TVR, MACE, and stent thrombosis. However, significant interactions were present such that the relative reductions in cardiac death, TV-MI, TVR, and MACE were greater in the Asian compared with non-Asian trials (although stent thrombosis was reduced consistently across geographies). Differences in how the information derived from IVUS was used to optimize stent implantation may contribute to this geographic heterogeneity.