The HREVS (Hybrid coronary revascularisation vs. standard) trial found that there was no significant difference between percutaneous coronary intervention (PCI), coronary artery bypass grafting (CABG), and the hybrid approach (CABG plus PCI) or patients with multivessel disease. Vladimir Ganyukov, who presented the study at the 2017 Transcatheter Cardiovascular Therapeutics (TCT) meeting (29 October–2 November, Denver, USA), outlines the rationale for the hybrid approach and the key findings of the HREVS study.
At present, revascularisation for multivessel coronary artery disease is achieved mainly through CABG or through PCI with drug-eluting stents. However, excellent outcomes with a left internal mammary artery graft (LIMA) to a left anterior descending artery graft approach and favourable outcomes with contemporary drug-eluting stents have led to the consideration of hybrid coronary revascularisation—a LIMA graft to a left anterior descending artery graft plus PCI (with drug-eluting stents) for the remaining vessels—as a third option for managing patients with multivessel disease.
The potential utility of the hybrid approach has been discussed for more than 20 years. CABG and PCI, as separate procedures, both have their disadvantages. For example, the invasiveness for CABG and the risk of repeat revascularisation with PCI. Therefore, theoretically, the optimal revascularisation approach would be to combine decreased invasiveness—with low risk of perioperative complications—with increased durability and survival. Furthermore, combining a minimally invasive LIMA graft to left anterior descending graft procedure with PCI (using drug-eluting stents) for the other vessels would not require aortic manipulation and extracorporeal life support. This, potentially, would result in a decreased risk of perioperative complications and incidence of stent failure.
In the absence of prospective, randomised trial data comparing the three different approaches—ie hybrid vs. PCI vs. CABG—the HREVS trial was designed to be the first randomised study to assess safety and efficacy of these contemporary coronary revascularisation strategies.
It was a prospective, single-centre, randomised trial comparing the three revascularisation methods; the arms used the best techniques and devices in routine practice. Overall, 53 patients were treated with PCI, 50 underwent CABG, and 52 received the hybrid approach. In this study, the hybrid approach consisted of minimally invasive direct CABG with a LIMA graft to a left anterior descending artery graft followed by PCI for the other vessels (performed one to three days after the CABG procedure). The study was powered for the primary endpoint of residual myocardial ischaemia assessed by single-photon emission computed tomography (SPECT) at 12 months. Secondary endpoints were major adverse cardiac and cerebrovascular events (MACCE) and target vessel/graft failure.
At 12 months, there were no statistically significant differences in residual myocardial ischaemia (assessed by SPECT) and MACCE between groups. The primary study endpoint of non-inferiority was met. Thus, hybrid revascularisation fails to reduce myocardial ischaemia and major adverse cardiovascular and cerebrovascular events when compared with CABG alone and PCI alone.
The main finding from this first randomised study is that all three strategies show similar efficacy in terms of the primary endpoint of residual myocardial ischemia (assessed by SPECT). This is actually a good result for hybrid revascularisation because a residual ischaemia is not only an index of revascularisation quality but it is also an important, and validated, prognostic index. Until now, the recommendation for hybrid revascularisation in specific patient subsets (at experienced centres) was only based on the consensus of the opinion of experts (Level of evidence C). My opinion is that after the HREVS study, we have a higher level of evidence for hybrid revascularisation (Level of evidence B) for which to base recommendations. We can now say that PCI, CABG, or the hybrid approach are equally feasible in suitable patients with multivessel disease coronary artery disease patients and with SYNTAX score 19.
Vladimir Ganyukov is at the Department of Interventional Cardiology, State Research Institute for Complex Issues of Cardiovascular Diseases in Kemerovo, Russia.