Physicians continue to agonize over decisions on the best treatment option for multi-vessel (MVD) coronary artery disease. We discuss over here not left main disease; which apparently is a different disease from multi-vessel disease in terms of clinical outcomes with percutaneous coronary intervention (PCI) as has been seen in 5 years follow up of the SYNTAX trial. We shall focus on 2 big trials presented in this year’s ACC Meeting and simultaneously published in the NEJM. Both studies (one randomized but underpowered and the other a large observational one) come up with conclusions that death rate was similar between CABG surgery and PCI in patients with MVD. The rates of spontaneous myocardial infarction and repeat revascularization were greater in the PCI groups then in patients who underwent CABG. Both trials used a second generation drug eluting stent (DES) that is well known (as seen in randomized trials) to result in significantly lesser death, myocardial infarction, restenosis and stent thrombosis than earlier generation DES and bare metal stents.
The BEST trial conducted in East Asia began by wanting to randomize almost 1800 patients of MVD, but had to abort the study after 880 patients were recruited because of slow enrolment. The primary endpoint was a composite of death, myocardial infarction or myocardial revascularization at 2 years post randomization. At 2 years the primary endpoint had occurred in 11% of PCI patients and 8% of patients in the CABG group. At longer follow up of 4.6 years the primary end point was seen in 15% of the PCI group versus 11% in the CABG patients. There were no significant differences seen in the two groups in the occurrence of safety end point of death, myocardial infarction or stroke. The rates of repeat revascularization and spontaneous myocardial infarction were significantly higher in patients who underwent PCI than those who had CABG. The BEST Trial concluded that PCI with the everolimus-eluting stent was not non-inferior to CABG patients with MVD. The increased rates of repeat revascularization and spontaneous myocardial infarction did not result in greater deaths after PCI.Strokes were similar in both groups and the authors explain this may have been due to the fact that Asians have less calcification in their aorta than Western patients and also because 64% patients in the CABG group had off-pump surgery. It is important to note that the PCI group was administered clopidogrel with aspirin and not parserl or tricagrelor, which are considered to have superior clinical efficacy. Also complete revascularisation was done in only 51% of PCI patients as opposed to 72% in the CABG cohort (complete revascularisation being defined as revascularisation in all diseased segments that were at least 2 mm in diameter).
The second study examined clinical outcomes in an observational registry between patients of MVD provided PCI or CABG. Among almost 35,000 patients, 18,000 patients were selected for comparison of outcomes and divided into 2 cohorts. Various sophisticated statistical methods (propensity score matching) were employed to mitigate confounders and bias to the barest minimum. At a follow up of 2.9 years PCI with everolimus DES had the same risk of death, greater risk of myocardial infarction and repeat revascularization, but a lower risk of stroke as compared to CABG. The conclusion was that in a contemporary clinical practice registry, rates of death were similar with PCI with everolimus DES and CABG. The risk of increased myocardial infarction with PCI was seen only in patients with incomplete revascularization; hence the authors suggest that the choice between PCI with everolimus DES and CABG may depend on whether complete revascularization can be achieved with PCI. PCI may be the option if complete revascularization is deemed possible and the short-term risks of death and stroke in CABG versus long-term risks of a repeat procedure have been explained to the patient. The increased myocardial infarction rates were due to spontaneous and not procedural myocardial infarction. But this trial does not reveal the anti platelet regimen used in the PCI group.
The large randomized Triton and Plato trials have convincingly demonstrated significantly better clinical outcome benefits with praugerel and tricagrelor versus cloideogrel in acute coronary syndrome patients subjected to PCI; and recently the DAPT Trial showed significant lowering of stent thrombosis by almost 70% with dual anti platelet therapy extended another 18months after 1 year versus placebo (0.4% vs. 1.4%); and rate of myocardial infarction reduced by approximately 50% with prolonged dual therapy (p <. 001) even in patients without stent thrombosis. The SYNTAX Trial so far the largest randomized study investigated clinical outcomes in 1095 patients with 3 – vessel disease divided into PCI (with first generation paclitaxel DES) and CABG groups. The trial found after 5 years follow-up that results were dependent upon lesion complexity; in patients with low SYNTAX score (0-22), PCI and CABG had similar major cardiovascular and cerebrovascular adverse events (33% vs. 27% respectively. p=0.21) but greater rate of repeat revascularization (25% vs. 13%). Surgery was however superior in the intermediate (23-32) and high-risk groups (>33) as compared to PCI. In the low risk group PCI was therefore considered an acceptable alternative strategy to CABG in patients with 3-vessel disease.
These 3 trials assessing clinical outcomes of PCI versus CABG in patients with MVD do sharpen the picture, in that they suggest PCI with second generation DES can be considered as an alternative to CABG. The risks and benefits of PCI with a second generation DES versus CABG needs to be clearly explained to the patient having MVD by a heart team consisting of the physician, inteventional cardiologist and the cardiac surgeon. In most instances an informed patient will provide an unequivocal consent to the procedure he or she prefers; it is also imperative that the attending cardiologist and cardiac surgeon are aware of these 2 recent recent studies plus the SYNTAX trial exploring the subject to have clarity in their approach.