Mac versus PC, Republicans versus Democrats, chocolate versus vanilla … life is full of rivalries, and the world of medicine is no exception. Take cardiology and cardiac surgery, for example. Who’s better at mending a particular group of blood-starved hearts? The answer depends on the group of hearts – and perhaps on the group you ask.
In this climate of usually-friendly rivalry, Dr. William S. Weintraub (Christina Care Health System, Newark, DE) and his ASCERT study colleagues sought to compare the effectiveness of percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) for the treatment of patients with stable two- and three-vessel coronary artery disease. Observational registry data for over 180,000 patients was obtained from national PCI and CABG cohort databases. This was linked to claims data from the Centers for Medicare and Medicaid Services in order to calculate survival curves for each cohort. Propensity scores and inverse-probability weighting was used to address the treatment-selection bias that is an inevitable result of physicians’ judgment in nonrandomized, real-world studies.
And the winner is? At one year post-procedure, adjusted mortality in the combined cohort was just over 6%, with no significant difference between the groups. At four years, however, CABG demonstrated a significantly lower adjusted mortality than PCI (16.4% vs. 20.8%; risk ratio, 0.79; 95% CI, 0.76-0.82). Does this end the debate over this group of patients?
Not quite, says editorialist Dr. Laura Mauri (Brigham and Women’s Hospital, Boston, MA). As she points out, treatment selection is usually the result of careful clinician judgment, rather than a random distributional imbalance ripe for statistical adjustment. Unmeasured factors, such as patient frailty, may simultaneously influence treatment selection and affect survival. As a consequence, we have to be somewhat cautious about the validity of the results of observational treatment-strategy studies.
“For decades, cardiologists and cardiac surgeons have worked together to figure out how to get the right procedure to the right patient at the right time,” says cardiologist and NEJM deputy editor Dr. John Jarcho, “The ASCERT study will certainly add to that debate.”
For those of us looking after patients needing revascularization, it’s an interesting time to pull up a chair, grab a drink, and watch this healthy rivalry unfold. Coffee or tea?