This study is the first population-based study to report the application of the CHA2DS2-VASc score to assessments of perioperative of noncardiac surgery outcomes in patients with AF. The CHA2DS2-VASc score was highly associated with postoperative major infection, intensive care unit stay, and 30-day mortality. Prolonged length of hospital stay and elevated medical expenditures were also noted in patients with higher CHA2DS2-VASc scores. The biological gradient effects existed in the CHA2DS2-VASc score associated with postoperative infections and mortality. The association between CHA2DS2-VASc score and postoperative adverse events remained significant for various subgroups.
Age, sex, and socioeconomic covariates commonly influence perioperative outcomes [23–25]. Postoperative complications are mainly determined by types of surgery and anesthesia, as well as pre-existing medical conditions such as hyperlipidemia, mental disorder, liver cirrhosis, renal disease, chronic obstructive pulmonary disease, Parkinson’s disease and cancer. These conditions are also considered to be potential associated factors of postoperative complications and mortality [23, 26–31]. To avoid bias when investigating the relationships between the CHA2DS2-VASc score and postoperative outcomes, we used multivariate logistic regression models to adjust for these potential confounding factors. We then showed that the CHA2DS2-VASc score was a statistically significant predictor for postoperative infection and in-hospital mortality in patient with AF.
Recent studies have reported that preoperative AF clearly increases the risk of perioperative stroke and adverse cardiovascular events, as well as short-term and long-term mortality [18, 32, 33]. Whether various CHA2DS2-VASc scores are correlated with other postoperative complications in AF patients undergoing noncardiac surgeries remains unclear. According to the present data, incremental increases in CHA2DS2-VASc scores caused a two- to three-fold risk in infection-related postoperative complications. The possible explanation is that each component of the scoring systems was proven to be independently associated with higher risks of postoperative infection and mortality [20, 21, 25, 34–36]. In our previous report and present investigation, patients with a previous stroke had double the risk of postoperative mortality than patients without previous stroke, either in the entire or AF populations . Moreover, each of these factors has been independently recognized to affect outcomes in AF. For example, the coincidence of congestive heart failure in a patient with AF may lead to decreased cardiac output, more serious alveolar flooding and reduced microbial clearance, which makes patients more prone to pulmonary infection. The CHA2DS2-VASc score predicts stroke risk in AF patients and research has shown that up to 50% of patients who had acute stroke have clinical evidence of aspiration pneumonia or sepsis, demonstrating its predictive role for infectious outcomes [20, 37]. On the basis of these findings, we postulate that the CHA2DS2-VASc score is strongly associated with postoperative complications in AF patients. However, this assumption should be validated in future prospective randomized trials.
Preoperative AF was independently associated with higher postoperative complications in patients undergoing noncardiac surgery . In the current clinical settings, the Revised Cardiac Risk Index or the American College of Surgeons National Surgical Quality Improvement Program risk model calculator were used to assess the cardiovascular risk in all patients who were scheduled to undergo noncardiac surgeries . According to the clinical practice guidelines, electrocardiogram and echocardiography are common tools for assessing perioperative outcomes that are not recognized as risks in aforementioned risk model calculators [16, 17, 38]. However, the comprehensive assessment of preoperative risk stratification in AF population has not been ideally established. Therefore, our study examined the possibility of applying the CHA2DS2-VASc score to surgical patients in order to assess infectious complications and mortality.
A retrospective population-based cohort study was conducted to investigate which risk score for perioperative outcomes prediction in patients with AF undergoing noncardiac surgery and concluded that the CHA2DS2-VASc score provides acceptable preoperative risk stratification for major perioperative events including mortality . Compared with our study, the authors did not adjust some possible potential confounding factors into their analysis (such as socioeconomic status, hyperlipidemia, liver cirrhosis and types of anesthesia). Additionally, the patient cohort in our study was larger and from a more recent time period compared with the previous cohort study . Furthermore, the present study provides evidence that patients with AF with an increased CHA2DS2-VASc score have an increased risk for postoperative adverse events compared to patients with AF only. With these results, clinicians can precisely access the risk of adverse outcomes and allocate medical resources in AF patients with coexisting medical conditions when they undergo noncardiac surgeries.
This study had several inherent limitations. First, several unmeasured factors, such as the type of AF (paroxysmal or non-paroxysmal), frailty, various perioperative AF medication management strategies, drug compliance, alcohol consumption, body mass index, cigarette smoking, physical activity level, and perioperative heart rate status, were unavailable in our database. Failure to consider the aforementioned variables may have led to a certain degree of residual bias. However, considering the significance and magnitude of the observed effects, it is unlikely that these limitations compromised the results. Second, comorbidity severities (such as CHA2DS2-VASc score components) and coexisting medical conditions were defined by registered diagnosis codes, not by laboratory data, image studies or clinical evaluations. In addition, because the study cohort included only Taiwanese patients with AF, the results may not be generalizable to other populations. Finally, our investigation was a retrospective observational study, which had certain methodological limitations. Understanding the causal inference between the CHA2DS2-VASc score and perioperative outcomes requires future prospective studies.
In conclusion, the CHA2DS2-VASc scoring system is an important independent predictor for postoperative major infections, 30-day mortality, and consumption of medical resources in patients with AF undergoing noncardiac surgeries. Our study suggests that perioperative care teams could apply CHA2DS2-VASc scores preoperatively for AF patients receiving noncardiac surgeries. Future studies are needed to assess the application of CHA2DS2-VASc scores to AF patients undergoing noncardiac surgeries.