FREEDOM (Part III)
Now, we cardiologists had a bright idea. The reason that angioplasty was not better than bypass surgery was that we were comparing apples to oranges. The reasoning went that if we compared “like” patients that angioplasty would be superior. So, off we went to do another study.
This one is named SYNTAX. SYNTAX stands for SYNergy Between PCI With TAXUS and Cardiac Surgery. I bet you can already figure out what the problem will be. This study was started in March 2005 and enrolled 1,800 patients. It ended April 2008, and the final data was done this year.
Feeling our “oats” we went after the big Kahuna. To get into the study, you needed to have three vessel disease, Left Main disease or Left Main equivalent with or without one, two or three vessel disease. In other words, these patients had a large burden of disease including the big no-no that is left main. We were so sure of ourselves that we went for broke.
The main difference between this study and the previous trials to answer this question is the SYNTAX score. This score is very useful but very complicated. Even the study sites often got it wrong. The score was always “overhead,” so it was corrected before a patient could be entered in the study. The score uses the coronary tree diagram and then weighs the lesion for importance. I will not go into it further because the exact way it was done is not the point. The point is that the score allowed us to differentiate between low risk, medium risk and high risk.
The study was an “all comer” study. A surgeon and a cardiologist had to agree that the patient could technically be done either way. The only exclusions were previous interventions, acute MI or need for other cardiac surgery like valve replacement. Two groups were then formed, one for Left Main and one, two 0r three vessel disease, and one for all other lesions.
At the end of the study, 897 patients had CABG (coronary artery bypass grafts), and 903 had PCI (percutaneous coronary intervention). Two registries were formed for those patients who were considered for the trial but could only be done one way. The CABG registry had 1,077 patients, and the PCI registry had 198 patients. In each of the two study groups, 28% had diabetes and 71% did not. The primary endpoint was 12 months.
All cause death
Any repeat PCI or CABG
Average age was 65, 78% male, average SYNTAX score was 29, left main was 34% in each group, number of stents implanted in PCI group 4.6, number of bypass grafts 2.8 average with 3.2 distal attachments.
At 12 months, all cause death was the same roughly 4%. Higher strokes were seen in the CABG group 2.2% vs. 0.6%. Higher MI’s in the PCI group 4.8% vs 3.2%. All cause death/MI/CVA equal at 7.7%. Need for repeat revascularization PCI 13.7% vs 5.9% for CABG. This drives the results in favor of CABG 12.1% vs 17.8% for PCI.
So, the final answer was that in this trial, both PCI and CABG could be done, but the cost is a higher redo rate for PCI. However… the real results did not come out until four years later.
Tags: acute MI, acute myocardial infarction, CABG, CABG v. PCI, coronary artery bypass graft, coronary tree diagram, PCI, percutaneous coronary intervention, synergy between pci with taxus and cardiac surgery, SYNTAX score, SYNTAX study, SYNTAX Trial, vessel disease