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Invasive management may significantly reduce mortality in patients with unstable angina

Patients with unstable angina who underwent routine invasive coronary angiography and revascularization showed a lower risk of death compared with patients who did not undergo the procedure, according to research published in Annals of Internal Medicine.

“Most randomized controlled trials of routine versus selective invasive coronary angiography have high rates of crossover from control to intervention groups and do not include subgroup analysis for unstable angina,” Sara Vogrin, MBBS, MBiostat, from the University of Melbourne, and colleagues wrote. “Consequently, no clear, specific recommendations exist regarding the use of angiography in unstable angina.”

Vogrin and colleagues performed a longitudinal study to evaluate how a routine invasive management strategy that starts with invasive coronary angiography and is followed by revascularization as indicated influences the 12-month all-cause mortality risk in patients with unstable angina. They assessed clinically coded discharge data between 2001 and 2011 from hospitals in Victoria, Australia using discrete-time survival analysis with propensity score adjustment and sensitivity analysis. A total of 33,901 emergently admitted patients with unstable angina who did (43%) or did not receive angiography during their initial hospitalization were included. Participants were balanced on 44 covariates of propensity score.

Results showed a 52% relative decrease in 12-month mortality in patients who received routine angiography (HR, 0.48 [95% CI, 0.38 to 0.61]). Compared with diagnostic angiography alone, revascularization was not associated with an additional statistical mortality benefit. Among patients who received angiography within 2 months of their index unstable angina, the absolute cumulative probability of death at 12 months was 5% lower than those who did not receive it (3.2% vs. 8%). There was no difference by age, sex or comorbid conditions in the relative effect of angiography.

“Routine invasive diagnostic angiography up to 2 months after an emergent admission for unstable angina, with or without subsequent revascularization, in association with optimum medical therapy might prevent up to 5 deaths per 100 admissions for unstable angina during the 12 months after hospitalization for the initial episode,” Vogrin and colleagues concluded. “[A] consideration for future trials of invasive management in unstable angina is how to incorporate the high rates of crossover between treatment groups and recurrent acute cardiac events in the analysis. Such trials also might assess the effect of routine angiography on subsequent quality of life and prevention of disability.”

In an accompanying editorial, Sanjit S. Jolly, MD, MSc, and P.J. Devereaux, MD, PhD, both from McMaster University in Ontario, Canada, argued that while Vogrin and colleagues re-identified the importance of evaluating the impact of an invasive strategy in unstable angina, the study did not sufficiently determine its effect and therefore, a large, definitive randomized trial is warranted.

“Until the results of such a trial become available, physicians evaluating patients with a diagnosis of unstable angina should first determine whether their symptoms are cardiac or noncardiac, because among patients with chest pain and negative biomarker measurements, only a small fraction have cardiac chest pain,” they concluded. “Whether chest pain is cardiac or noncardiac can be evaluated by using several noninvasive or invasive cardiac tests. In patients with negative biomarker values and truly unstable coronary disease, coronary revascularization remains a reasonable option, along with evidence-based medical therapies.” – by Alaina Tedesco

Disclosures: Vogrin and colleagues report primary funding from the National Health and Medical Research Council, Australia and BUPA Health Foundation. Jolly reports grants from Medtronic and Boston Scientific. Devereaux reports grants from Abbott Diagnostics, Boehringer-Ingelheim, Covidien, Octapharma, Phillips Healthcare, Roche Diagnostics and Stryker.