In Diabetics with Multivessel Disease SYNTAX Score Calculations Are Redundant

In diabetic patients with multivessel disease, anatomical complexity assessed by SYNTAX score is an independent predictor of combined events only por PCI patients, and has absolutely no consequence for surgery. The score should not be used to decide on a revascularization strategy. If the patient is diabetic and has multivessel disease, they simply ought to receive surgery.

This study, recently published in JACC, looked at the use of SYNTAX score to predict future cardiovascular events in diabetic patients with complex coronary artery disease undergoing PCI or CABG.

The FREEDOM (Future Revascularization Evaluation in patients with Diabetes mellitus: Optimal management of Multivessel disease) randomized diabetic patients with multivessel disease (>50% lesions) to PCI with first generation DES vs. CABG.

Primary end points were all cause death, non-fatal infarction, non-fatal stroke, and the classic composite of MACE was a composite of hard cardiovascular events and repeat revascularization.

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A total 1900 patients were randomized to PCI (n=953) vs CABG (n=947). The syntax score was considered an independent predictor of combined events at 5 years (HR per unit of score: 1.02; CI 95%l: 1.00 to 1.03; p=0.014) and a predictor of hard events (HR per unit of S Score 1.03; CI 95% 1.01 to 1.04; p=0.002) In the PCI cohort, but not in the CABG cohort.

Conclusions In DM patients with multivessel CAD, the complexity of CAD evaluated by the SS is an independent risk factor for MACCE and HCE only in patients undergoing PCI. The SS should not be utilized to guide the choice of coronary revascularization in patients with DM and multivessel CAD. (Comparison of Two Treatments for Multivessel Coronary Artery Disease in Individuals With Diabetes [FREEDOM]; NCT00086450).

There were more events in the PCI group regardless the score (low, intermediate or high) compared against CABG (36.6% vs. 25.9%, p=0.02; 43.9% vs. 26.8%, p<0.001; 48.7% vs. 29.7%, p=0.003, respectively).

Today, we could consider the FREEDOM obsolete for there have been many developments in PCI, as opposed to CABG, which remains the same.

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There is more evidence to prove this obsolescence: revascularization indication criteria with the FREEDOM was lesions >50%, vs today’s overwhelming evidence with functional revascularization; first generation DES stents in the freedom vs new generation stents with ultrathin struts and proven drugs such as everolimus; resorbable polymers have not yet been shown superior against permanent polymers, though all new generation stents have shown less thrombosis and fewer device related events. Finally, mandatory monitoring with intravascular imaging (IVUS or OCT), which also has shown to reduce events, and was not mandatory with the FREEDOM.

On the other hand, although CABG has not changed that much, it admittedly has excellent results, since the most relevant recent studies have shown neutral outcomes.  A few examples are the ART trial, which shows the superiority of bilateral grafts; the CORONARY and the PRAGUE 6, among others, which show differences between on and off pump CABG; and even studies we could consider almost cosmetic (with benefits in pain and early ambulation) such as the REGROUP, which tested endoscopic vs. conventional septoplasty.

Original title: SYNTAX Score in Patients with Diabetes Undergoing Coronary Revascularization in the FREEDOM Trial.

Reference: Rodrigo B. Esper et al. J Am Coll Cardiol 2018;72:2826–37.

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