Slideshow | The SYNTAX Study: The 3-year Outcomes of the SYNTAX Trial in the Subset of Patients with Left Main Disease

Patrick W. Serruys, MD PhD Erasmus Medical Center, Rotterdam

WASHINGTON, D.C.--For patients with left main (LM) disease, revascularization with PCI has comparable safety and efficacy outcomes to CABG, based on the three-year outcomes of the left main disease subset of patients. Therefore, co-principal investigator Patrick W. Serruys, MD, PhD, concluded that PCI is a “reasonable treatment alternative” in this patient population, in particular, when the SYNTAX Score is low or intermediate.

In 2009, the ACC/AHA PCI Guidelines were updated and raised LM stenting form Class III to Class IIb (Level B). Most recently, at this year’s European Society of Cardiology (ESC) conference in Stockholm, the ESC-EACTS Guidelines revised and upgraded LM (isolated or in conjunction with single-vessel disease) stenting from Class IIb (level C) to IIa (level B).

Of the 3,075 patients enrolled in SYNTAX, 705 had left main disease. They were randomized to either CABG (348 patients) or PCI with Boston Scientific’s Taxus stent (357 patients), with a 95.6 percent follow-up at three years, reviewed Serruys, from Erasmus Medical Center in Rotterdam, the Netherlands.

The SYNTAX investigators found that the all-cause death rate was 2.3 percent in the CABG group, compared with 1.8 percent in the PCI group during the third year of follow-up. The cumulative all-cause death across the three years was 8.4 percent in the CABG arm and 7.3 percent in the PCI arm.

The stroke rates were the same during the third year of follow-up—0.3 percent—and the cumulative stroke rate across the three years 4 percent for the CABG group versus 1.2 percent in the PCI group.

There were zero incidents of MI in the CABG group from year two to three, while the PCI group marked a rate of 1.5 percent. The cumulative MI rate is 6.9 percent in the PCI versus 4.1 percent in the CABG group.

The rate of repeat revascularization dropped considerably to 3.9 percent in the PCI arm, while the CABG arm also saw a drop to 2.6 percent. Due to a higher incidence rate in the first two years of follow-up, the PCI arm has a cumulative repeat revascularization rate of 20 percent, while the CABG group had a rate of 11.7 percent, representing a statistically significant difference.

Overall, the composite major adverse cardiovascular and cerebrovascular event (MACCE) rate was 5.7 percent in the PCI group, compared with 5.2 percent in the CABG group during the third year of follow-up. The cumulative MACCE rate also trended higher for PCI versus CABG (26.8 vs. 22.3 percent)—not a statistical significant difference.

Also, PCI outcomes are “excellent” relative to CABG in left main isolated and left main plus single-vessel disease, Serruys said.

He broke down the SYNTAX left main population by SYNTAX Score—low score (0 to 22), intermediate scores (23 to 32) and high score (33 or greater) over the three-year follow-up period. Evaluating the MACCE for each tercile, CABG had a higher MACCE rate in the 222 low score patients with left main disease, 23 versus 18 percent. For those 195 left main patients with intermediate SYNTAX scores, the MACCE rate was the same—23.4 percent. However, in the left main patient population of 284 with a high SYNTAX score, the CABG group had a lower MACCE rate compared with PCI—21.2 vs. 37.3 percent.

“For treatment of patients with left main disease, the next step is the EXCEL trial, which is the second randomized, controlled trial properly powered to cause a change in the guidelines,” Serruys concluded.