At 12-month follow-up, the primary endpoint was similar for CABG and DES in those with a low SYNTAX score. In contrast, MACCE occurred more often after DES implantation than after CABG in those with an intermedi- ate or high SYNTAX score.66 At 3 years of follow-up, the mortality rate was greater in subjects with 3-vessel CAD treated with DES than in those treated with CABG (6.2% versus 2.9%). The differences in MACCE at 5-year follow-up between those treated with DES or CABG increased with an increasing SYNTAX score.83 Although the utility of the SYNTAX score in everyday clini- cal practice remains uncertain, it seems reasonable to conclude from SYNTAX and other data that survival rates of patients undergoing PCI or CABG with relatively uncomplicated and lesser degrees of CAD are comparable, whereas for those with complex and diffuse CAD, CABG appears to be preferable.81 83 5.7.2. Studies Comparing PCI and CABG for Left Main CAD See 2012 SIHD Guideline Data Supplement (Table 8 13) for informational evidence tables.4 Of all patients undergoing coronary angiography, approxi- mately 4% are found to have left main CAD,84 >80% of whom also have significant ( 70% diameter) stenoses in other epi- cardial coronary arteries. In published cohort studies, it has been found that major clinical outcomes 1 year after revas- cularization are similar with PCI or CABG and that mortality rates are similar at 1, 2, and 5 years of follow-up; however, the risk of undergoing target-vessel revascularization is sig- nificantly higher with stenting than with CABG. In the SYNTAX trial, 45% of screened patients with unprotected left main CAD had complex disease that pre- vented randomization; 89% of those underwent CABG.66,81 In addition, 705 of the 1800 patients with unprotected left main CAD were randomized to either DES or CABG. 