1. Rates of clinical stroke after aortic valve replacement surgery were found to be 17%, more than twice the rate of 7% reported in the same cohort in the Society for Thoracic Surgery database.
2. Patients who had a moderate or severe stroke, defined by NIHSS score ≥10, had increased in-hospital mortality.
Evidence Rating Level: 2 (Good)
Study Rundown: Stroke is a rare but serious complication of aortic valve replacement (AVR) surgery; however, its clinical incidence and profile in individuals undergoing AVR have not been well described. Past estimates of the rate of stroke in this population have ranged from 1-10%, but such figures are thought to underestimate the true incidence. In this prospective study, the incidence of clinical stroke was found to be 17%, more than double the rate reported in the same cohort in the Society for Thoracic Surgery (STS) database. This incongruence was owed, in part, to the study design, which required more standardized and comprehensive neurological follow-up than indicated by standard clinical practice. The rate of silent cerebral infarctions indicated by magnetic resource imaging (MRI) was also found to be elevated in this cohort compared to previously published studies. Taken together, these results suggest an increased incidence of neurological complications than what has previously been reported for patients undergoing AVR, suggesting a need for increased neurologic surveillance in this population. Limitations of the study include the small sample size, recruitment of patients from only a single academic health system, and neurology follow-up only until day 7 post-op. The lack of any case-control comparison, coupled with the advanced age of participants (median 75.8 years) also precludes any population-wide generalization of results.
In-Depth [prospective cohort]: A total of 196 subjects undergoing acute valve replacement were enrolled from two hospitals in the University of Pennsylvania Health System. All patients were subject to evaluation by a neurologist pre-operatively and post-operatively on days 1, 3, and 7. Neurological exam included designation of National Institutes of Health Stroke Scale (NIHSS) scores to evaluate stroke severity. The overall clinical stroke rate was 17% (95% CI, 12-23%), compared to a rate of 7% in the STS database. The median NIHHS score of patients with clinical stroke was 3 (IQR 1-9). Stroke was associated with an increased length of stay (median 12 vs 10 days, p = .02) but not a significantly increased mortality (9% vs. 4%, p = .28). A moderate to severe stroke, defined by an NIHSS score ≥10, was associated with increased mortality (38% vs 4%, p= .01). An MRI was obtained from 129 patients post-operatively. Of the 109 patients without a stroke who underwent an MRI, the rate of silent radiographic cerebral infarction was found to be 54% (95% CI, 5-64%).
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