A strategy of complete revascularisation was superior to culprit lesion-only percutaneous coronary intervention (PCI) in reducing the risk of cardiovascular death or myocardial infarction (MI) in patients with ST-segment myocardial infarction (STEMI) and multivessel coronary artery disease. The timing of PCI for the non-culprit lesions had no significant impact on outcomes observed, and the main driver of the decreased risk was a reduction in the rates of MI.
The global COMPLETE study, presented at the European Society of Cardiology Congress (ESC 2019; 31 August–4 September, Paris France) and simultaneously published in the New England Journal of Medicine (NEJM), also noted a decline in the risk of a composite of CV death, MI, or ischaemia driven revascularisation.
At a press conference preceding the main presentation, Shamir R Mehta (Population Health Research Institute, Hamilton, California, USA) outlined the final results from the trial on behalf of the investigators. He said: “Patients undergoing primary PCI to the culprit lesion for STEMI are often found to have multivessel coronary artery disease, with one or more angiographically significant nonculprit lesions. There is uncertainty on how best to manage these nonculprit lesions—whether to routinely revascularise them with PCI, or to manage them conservatively with guideline directed medical therapy alone.”
COMPLETE was a randomised, comparative effectiveness study of complete versus culprit-only revascularisation strategies to treat multivessel disease after early percutaneous coronary intervention for ST-segment elevation myocardial infarction, in which researchers randomly assigned (1:1) patients with STEMI and multivessel CAD who had undergone successful culprit lesion only PCI to a strategy of either complete revascularisation with PCI of angiographically significant nonculprit lesions (2,016) or to no further revascularisation (2,025). Randomisation was stratified according to the timing of the nonculprit lesion PCI. This was performed either during the index hospitalisation, or after discharge from hospital (no later than 45 days after randomisation), a decision that was taken before participants were randomised. Mehta stressed that this was an “important caveat of the design of the trial”. And he added: “It is important to note that all patients received guideline directed medical therapy.”
The first co-primary outcome was a composite of cardiovascular (CV) death or MI; the second was a composite of CV death, MI or ischaemia-driven revascularisation. A key secondary outcome was CV death, new MI, ischaemia-driven revascularisation, unstable angina, and New York Heart Association (NYHA) class IV heart failure. Median follow-up was for three years, and the longest follow-up was for more than five years. Nonculprit lesions were located in the left anterior descending (LAD) artery for approximately 10% of cases and in the proximal LAD for about 40% of cases, in both groups.
Mehta said: “One of the most important parameters in the trial was that complete revascularisation was achieved in over 90.1% of patients who were allocated to the nonculprit lesion PCI arm. That means that they had a SYNTAX score of zero; there was no significant disease left behind in that group.”
The first co-primary outcome occurred in 158 patients (7.8%) in the complete revascularisation group, and 213 (10.5%) in the culprit lesion only PCI group (hazard ratio [HR] 0.74, 95% confidence interval [CI] 0.6–0.91, p=0.004).
Mehta explained: “The number needed to treat to prevent one of these events over a period of three years is 37 patients. The main benefit occurs over the long-term, with continued divergence of the Kaplan-Meier curves [of the two cohorts]. A complete revascularisation strategy has an effect over long term events, similar what we have seen with CABG [coronary artery bypass graft] surgery 20 years ago.”
The second co-primary outcome occurred in 179 patients (8.9%) in the complete revascularisation group and 339 patients in the culprit lesion only group (HR 0.52, 95% CI 0.43–0.61, p<0.001). The benefit of complete revascularisation was consistently observed for both co-primary outcomes, regardless of the intended timing of the nonculprit lesion PCI (p=0.62 and p=0.27 for first and second co-primary outcomes, respectively). “There is no interaction, said Mehta, “meaning that it doesn’t seem to matter whether it is performed early during the index hospitalisation, or later after discharge from hospital, the benefits on hard outcomes, CV death or MI, seem to be preserved. And the reason for that might be because the benefits of complete revascularisation on hard outcomes occurred over the long-term.”
He continued: “The biggest impact on the primary endpoint was a reduction in myocardial infarction which was reduced by 32%, a highly significant risk reduction. In addition to this, ischaemia driven revascularisation was reduced and unstable angina was reduced. Cardiovascular and all-cause deaths were non-significantly fewer in the complete revascularisation group than the culprit-only group … but the trial was not powered to detect reductions in these two endpoints.”
There were no significant differences in any of the safety outcomes.