Cardiology · Medical Literature
Perioperative cardiac risk stratification: is functional capacity assessment able to predict perioperative complications, including death?
Abstract
Perioperative risk screening seeks to optimize medical decision-making by identifying cardiac risk in patients undergoing noncardiac surgery. The current guidelines of organizations such as the European Society of Cardiology (ESC) and the Brazilian Society of Cardiology (SBC)incorporate assessments of subjective functional capacity, often using the threshold of 4 METs as a marker of low functional capacity. Despite recent updates to these guidelines, the literature remains conflicting, and the predictive power of subjective tools for perioperative outcomes is uncertain. We conducted a systematic review, in accordance with PRISMA guidelines, on the effectiveness of subjective functional capacity assessment tools regarding their predictive power for perioperative cardiac complications, including death. Four databases were searched: PUBMED, SCOPUS, WOS, and Science Direct. The results indicate that the self-reported ability to climb two flights of stairs, although demonstrating associative power, often did not improve the predictive power of risk models. In contrast, more comprehensive assessment tools with continuous data, such as the Duke Activity Status Index (DASI) and weekly levels of physical activity, appear to be more promising. These results suggest that current perioperative risk stratification guidelines need to be critically re-evaluated with regard to the inclusion of subjective functional capacity. It is of paramount importance to effectively distinguish the associative power of the subjective assessment of functional capacity from its predictive power when compared with information already obtained from the patient.
Clinical relevance
This systematic review addresses a critical gap in perioperative medicine: whether subjective functional capacity assessment tools — widely embedded in ESC and SBC guidelines using the 4-MET threshold — genuinely predict cardiac complications and death in patients undergoing noncardiac surgery, rather than merely demonstrating statistical association. The affected population is broad, encompassing all adult surgical candidates requiring preoperative cardiac risk stratification. Clinicians should take note now because current guideline recommendations may be overstating the predictive utility of simple subjective tools, potentially leading to suboptimal risk stratification and medical decision-making.
Key findings
1. The systematic review followed PRISMA guidelines and searched four major databases (PubMed, SCOPUS, Web of Science, and Science Direct), reflecting a rigorous and reproducible methodology. 2. Subjective self-reported ability to climb two flights of stairs demonstrated associative power with perioperative outcomes but frequently failed to improve the predictive performance of established cardiac risk models beyond baseline. 3. The Duke Activity Status Index (DASI), a more comprehensive questionnaire-based tool yielding continuous data, emerged as a more promising predictor of perioperative cardiac complications compared to binary or threshold-based assessments. 4. Weekly levels of physical activity assessed via continuous metrics similarly showed superior predictive potential relative to simple categorical functional capacity thresholds such as the 4-MET cutoff. 5. The universally applied 4-MET threshold endorsed by ESC and SBC guidelines was identified as a subjective marker of uncertain independent predictive value, raising questions about its standalone utility in risk models. 6. A key conceptual finding was the distinction between associative power (correlation with outcomes) and incremental predictive power (improvement in risk model discrimination), with current subjective tools failing to consistently demonstrate the latter.
Practice implications
Clinicians performing preoperative cardiac risk stratification for noncardiac surgery should consider replacing or supplementing simple binary functional capacity questions (e.g., stair-climbing ability, 4-MET threshold) with more granular, continuous assessment instruments such as the DASI or structured physical activity quantification, particularly in patients where risk model discrimination is critical. Current ESC and SBC guideline recommendations incorporating subjective functional capacity should be applied with caution, recognizing that a positive subjective assessment may not meaningfully reduce estimated perioperative cardiac risk beyond what is already captured by validated scoring tools. Multidisciplinary perioperative teams should advocate for guideline re-evaluation and, where feasible, consider objective functional capacity testing (e.g., cardiopulmonary exercise testing) in higher-stakes surgical candidates to improve predictive accuracy.