The SNYTAX score II may be used to guide decision making between PCI and CABG

The SYNTAX score was designed to assess the severity of coronary artery disease (CAD). However, this score has not aided doctors in assessing whether a CAD patient would benefit more from percutaneous coronary infusion (PCI) or coronary artery bypass graft (CABG). Here, researchers develop a new scoring system. The new system uses some criteria from the SYNTAX system as well as individual traits to determine whether PCI or CABG is likely to be more advantageous for CAD patients.

Coronary artery disease (CAD) that requires intervention can be treated with either PCI or CABG surgery. The first is a non-surgical method based on catheterization and stent placement, whereas the other is a major surgery using a graft to bypass the blocked artery.

The SYNTAX scoring system was first published in 2005. It was designed to aid doctors in assessing the complexity of CAD in individual patients. The system uses the size of lesions (sites of blockage) and their location to assign a score. These scores then fall into three categories of low, medium, or high-risk. However, in follow-up studies, SYNTAX scores did not consistently predict whether patients would benefit more from PCI or CABG. Both CAD severity and individual traits could affect the long-term benefits of PCI or CABG. Therefore, researchers developed a new system called “SYNTAX score II”, which is based on both the original SYNTAX score and individual traits such as age, sex, and co-existing diseases. Thus, the new score combines both anatomy-related and clinical data (related to the patient's health status).

The SYNTAX trial included 1800 patients that were followed-up for 4 years. It documented individual traits and treatment of choice (PCI or CABG). Using these details, a combination of 8 traits could predict the risk of death in the 4 years following the procedure. These traits comprise the new SYNTAX score II, and include:

• Original SYNTAX score
• age
• creatinine clearance (CrCl; a measure of kidney function)
• left ventricular ejection fraction (LVEF; a measure of heart function)
• the involvement of left main artery (LMA; a main coronary artery supplying the heart)
• gender
• chronic obstructive pulmonary disease (COPD; a severe lung disease)
• peripheral vascular disease (PVD; an occlusive disease of the blood vessels outside the heart)

The results indicated that certain traits affect treatment outcomes and can be used to guide decision making between PCI and CABG: younger age, female sex, reduced LVEF (i.e. heart failure), and an extensive CAD involving multiple vessels (NOT including the LMA) favored CABG compared with PCI; whereas older age, co-existing COPD, or LMA involvement favored PCI treatment.

In contrast to the common belief, neither method has shown superiority in patients with co-existing diabetes. However, other individual factors has to be taken into account when making treatment choices for such patients.

This study has shown that a score comprised of both anatomical and clinical variables could guide decision making between PCI and CABG in patients with advanced CAD.

Although the SYNTAX II score seems to be improved and more personalized, it doesn't seem to substantially change the process of decision making, as practiced today.

If you are considering PCI or CABG for your CAD, talk to your doctor about the long-term benefits of each procedure.