Heavily Calcified Coronary Lesions Predictor of Long Term Mortality: SYNTAXES Trial

Studies have shown that coronary artery calcification (CAC) is a strong determinant of surgical (ie, coronary artery bypass grafting [CABG]) versus percutaneous revascularization. However, the extent to which coronary calcification modifies the effect of CABG versus PCI and influences long-term mortality among patients undergoing coronary revascularization is not well characterized. Therefore, Dr Patrick W. Serruys and his team conducted a study to assess 10-year all-cause mortality in patients with HCLs undergoing PCI or CABG.

In SYNTAX (Synergy Between PCI With Taxus and Cardiac Surgery) trial, the researchers randomized 1,800 patients with 3-vessel and/or left main CAD to PCI with first-generation drug-eluting stents (n = 903) or CABG (n = 897), with a planned follow-up of 5 years, the results of which have been previously reported. The SYNTAX Extended Survival (SYNTAXES) study was an investigator-initiated extended follow-up study to capture vital status up to 10 years among the original trial participants.

In this present study, Dr Patrick W. Serruys and his team conducted a substudy of SYNTAX Extended Survival study that assessed 10-year all-cause mortality according to the presence of HCLs within lesions with >50% diameter stenosis and identified during the calculation of the anatomical SYNTAX score among 1,800 patients with the 3-vessel disease and/or left main disease randomized to PCI or CABG.

Key findings of the study:

• Upon analysis, the researchers found that the 532 patients with at least one heavily calcified lesion in SYNTAXES had higher crude mortality at 10 years than the 1,268 without (36.4% vs 22.3%; HR 1.79).
• In multivariate analysis, after adjustments, they noted that HCLs were an independent predictor of 10-year mortality (HR 1.36).
• They observed a significant interaction in mortality between treatment effect (PCI and CABG) and the presence or absence of HCLs.
• Although CABG held a survival advantage over PCI among those without heavily calcified lesions (26.0% mortality at 10 years vs 18.8%; HR 1.44), they noted that the two procedures were associated with a similar prognosis in patients with heavily calcified lesions (10-year mortality 34.0% vs 39.0%; HR 0.85).

The authors concluded, "At 10 years, the presence of an HCL was an independent predictor of mortality, with a similar prognosis following PCI or CABG. Whether HCLs require special consideration when deciding the mode of revascularization beyond their current contribution to the anatomical SYNTAX score deserves further evaluation."

In an accompanying editorial Dr Usman Baber wrote, "A novel insight from the present analysis is that HCLs modified the treatment effect of CABG versus PCI on mortality risk…although assessing the degree of coronary complexity is the initial step in evaluating revascularization approaches, the present work reminds us that we should equally consider noncoronary factors, along with patient preference, in these complex clinical decisions"

For further information visit:

https://www.jacc.org/doi/full/10.1016/j.jcin.2021.10.026