Trends, Predictors, and Outcomes of Stroke After Surgical Aortic Valve Replacement in the United States.
BACKGROUND
Postoperative stroke is a devastating complication after aortic valve replacement (AVR). Our objective was to use a large national database to identify the incidence of and risk factors for stroke after AVR, as well as to determine incremental mortality, resource use, and cost of stroke.


METHODS
We identified 360,437 patients who underwent isolated surgical AVR between 1998 and 2011 from the National Inpatient Sample (NIH) database. Mean age was 66 ± 32 years. Multivariable regression and propensity matching were used to identify risk factors and the effect of stroke on outcomes. Patients were stratified according to the Elixhauser comorbidity score (ECS) into low- (0-5), medium- (6-15), and high-risk (16+) categories.


RESULTS
Stroke after AVR occurred in 5,092 (1.45%) patients. The incidence of stroke declined from 1.69% in 1999 to 0.94% in 2011 (p < 0.001). Increasing age and higher comorbidities were the main predictors of stroke (each p < 0.001). The highest-volume centers (>200 AVRs/y) had the lowest rate of stroke (1.2%). After multivariable adjustment, high-volume centers had lower odds of stroke in medium-risk (odds ratio [OR], 0.59; 95% confidence interval [CI], 0.37-0.94) and high-risk patients (OR, 0.39; 95% CI, 0.22-0.68) compared with the lowest-volume centers. For low-risk patients, volume was not associated with stroke. Patients who experienced stroke were hospitalized for 4 days longer, had an average of $10,496 higher costs, and had 2.74 (95% CI, 1.97-3.80) times higher odds of in-hospital mortality compared with those who did not experience stroke (all p < 0.001).


CONCLUSIONS
The incidence of stroke after AVR has decreased but remains a significant cause of morbidity in medium- and high-risk patients. Superior outcomes can be achieved in medium- to high-risk patients at high-volume centers.