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Doing aortic valve replacement and coronary artery bypass grafting (CABG) at the same time led to worse outcomes than valve replacement alone, but the difference was attributed to patient characteristics, researchers found.

Without accounting for patient differences, those who underwent both aortic valve replacement and CABG had worse survival at every time point from 30 days (97.6% versus 98.7%) to 10 years (43% versus 59%), as well as higher rates of septicemia, renal failure, prolonged ventilation, and atrial fibrillation in the hospital, according to Tomislav Mihaljevic, MD, of Cleveland Clinic Abu Dhabi in the United Arab Emirates, and colleagues.

In a propensity-matched analysis in which comorbidity burden was similar in each group, however, the survival rate was not different between the two groups at 1 year (93% in each group), 5 years (80% in each group), or 10 years (55% in the valve replacement alone group, and 50% in the valve+CABG group), the researchers reported in the Feb. 26 issue of the Journal of the American College of Cardiology.

The patients matched according to comorbidity burden -- both those who underwent valve replacement alone and those who underwent both procedures -- had similar and intermediate outcomes, whereas the patients who underwent valve replacement alone for isolated aortic stenosis had the best outcomes and those who underwent aortic valve replacement and CABG (AVR+CABG) but had a comorbidity burden too severe to be included in the propensity-matched analysis had the worst outcomes.

"Although current guidelines for treating valvular heart disease recognize that risk factors for coronary artery disease (CAD) and aortic stenosis frequently coexist, there are no recommendations for early evaluation or diagnosis of CAD in these patients," the authors wrote.

"The results of our study strongly suggest changing practice and modifying guidelines to include early evaluation of CAD in asymptomatic patients with severe aortic stenosis and risk factors for CAD so that timely AVR+CABG is performed before ischemic myocardial damage occurs," they wrote, adding that patients with more advanced comorbidities may be managed best with medical therapy alone.

But such a strategy of early evaluation and intervention "needs to be proven before surgery can be recommended in the asymptomatic patient," according to Linda Pape, MD, and Samuel Joffe, MD, of the University of Massachusetts Memorial Medical Center in Worcester.

The study "emphasizes the role of risk factors and comorbidities in determining surgical and longer-term survival among the broad range of aortic stenosis patients," they wrote in an accompanying editorial, but questions remain, including which patients will benefit from surgery and whether earlier intervention for CAD will improve outcomes.

"Only a randomized clinical trial will answer these questions," Pape and Joffe wrote. "In the meantime, we must apply our knowledge of risk factors for morbidity and mortality, of surgical outcomes, of the systemic nature of the disease, and, importantly, knowledge of our patients themselves in order to make the best decisions."

Previous studies identified an increased mortality risk when CABG was added to valve replacement in patients with severe aortic stenosis, and Mihaljevic and colleagues explored whether the extra risk was based on the additional surgical procedure or a difference in patient risk profile.

They examined data from 2,286 patients who underwent AVR+CABG and 1,637 who underwent valve replacement alone at a single center from October 1991 to July 2010. All of the valve replacements were performed with a single type of bovine pericardial prosthesis, the Carpentier-Edwards PERIMOUNT.

In general, the patients who underwent AVR+CABG were older and more likely to be male, had more severe symptoms, and were more likely to have left ventricular dysfunction and various comorbidities, including vasculopathies, hypertension, diabetes, and anemia. They had less severe aortic stenosis, however.

The researchers developed a propensity score to match patients in the valve-replacement-alone and AVR+CABG groups, and the process yielded 1,082 matched pairs.

In the propensity-matched analysis, outcomes were similar in the two groups, "suggesting that surgical revascularization at the time of [aortic valve replacement] neutralizes the adverse effects of CAD, provided that ischemic myocardial damage has not occurred," the authors wrote.

There were two groups of patients that could not be matched for the propensity score analysis -- those with isolated aortic stenosis who had few comorbidities and underwent valve replacement alone and those with aortic stenosis, CAD, myocardial damage, and advanced comorbidities who underwent AVR+CABG.

Outcomes were best in the former group and worst in the latter group.

"Patients' comorbidity profiles affected survival more than the procedure they underwent," according to Mihaljevic and colleagues.

"Cardiovascular risk factors and comorbidities must be considered in managing patients with severe aortic stenosis," they wrote.

From the American Heart Association: