Endpoints

The primary outcome was all-cause mortality after CABG using STS registry data for in-hospital deaths and the linked Medicare Denominator File for post-discharge deaths.¹² The secondary outcomes were stroke or systemic embolization (stroke, hemorrhagic stroke, transient ischemic attack, or systemic arterial embolism)¹³ and in-hospital major morbidity.

Incident stroke or systemic embolization was defined by using STS registry data to account for in-hospital strokes and Medicare Part A data to identify subsequent re-hospitalizations with stroke or systemic embolization as a primary diagnosis (International Classification of Diseases, 9^th Revision codes: 433.1, 434.x1, 430, 431, 432.0, 432.1, 432.9, 444,x, 435.x).

In-hospital major morbidity, a previously defined composite^{14, 15}, referred to any of the following post-procedure complications: permanent stroke, new cases of renal failure, prolonged ventilation (ventilation longer than 24 hours after surgery), reoperation for cardiac reasons (graft dysfunction, bleeding, valve dysfunction or other) and deep sternal wound infection.