Clinical Guideline Recommendations: The Role of Perioperative Myocardial Injury Biomarkers (High-Sensitivity Troponin and NT-proBNP) in Predicting Prolonged Inotropic Support and Hemodynamic Instability Following Heart Valve Surgery

Major guidelines focus primarily on noncardiac surgery, where perioperative myocardial injury (including Myocardial Injury after Noncardiac Surgery — MINS) is well-defined and surveillance with hs-cTn is recommended in high-risk patients. • The 2024 AHA/ACC Multisociety Guideline for Perioperative Cardiovascular Management for Noncardiac Surgery recommends preoperative and postoperative measurement of hs-cTn (and NT-proBNP/BNP) in selected high-risk patients to stratify risk for major adverse cardiovascular events (MACE), including myocardial injury/infarction. Thresholds include NT-proBNP ≥300 ng/L or BNP >92 ng/L as markers of elevated risk, with postoperative troponin surveillance at 24–48 hours in at-risk groups. However, this applies to noncardiac procedures, not cardiac surgery like valve replacement. • The 2022 ESC Guidelines on cardiovascular assessment and management of patients undergoing non-cardiac surgery similarly endorse hs-cTn and NT-proBNP/BNP measurement (pre- and post-operatively) for prognostic information in high-risk noncardiac surgery patients (Class IIa/IIb recommendations in relevant contexts). For cardiac surgery (including valve surgery), guidelines (e.g., from STS, ESC/EACTS on valvular heart disease, or perioperative care) do not mandate routine biomarker-based prediction of prolonged inotropic support as a standard of care. Risk stratification typically relies on scores like EuroSCORE II, STS score, preoperative echocardiography, clinical factors (e.g., NYHA class, atrial fibrillation, age), and intraoperative variables rather than mandatory hs-cTn or NT-proBNP thresholds for this specific endpoint. Emerging Evidence from Observational Studies (Relevant to Heart Valve Surgery) Several recent studies (primarily single-center or cohort-based) have investigated these biomarkers in the context of cardiac valve surgery and suggest potential utility: • Preoperative and postoperative hs-cTnT levels are independent predictors of prolonged ICU stay, need for prolonged inotropic support (>48 hours), cardiogenic shock, and worse outcomes (e.g., death, mechanical circulatory support). Elevated preoperative hs-cTnT (indicating chronic myocardial strain from valvular overload) and rising postoperative levels (reflecting perioperative injury) correlate with hemodynamic instability. • Preoperative NT-proBNP is a strong independent predictor of prolonged postoperative inotropic drug use (>48 hours), cardiogenic shock requiring ECMO or MCS, and related complications. High levels signal decompensated ventricular overload and higher sensitivity to surgical stress (e.g., cardioplegia, CPB). • In multivariate analyses, factors like age, preoperative atrial fibrillation, urgent rethoracotomy, and postoperative troponin rise often combine with these biomarkers to predict prolonged inotropic needs and instability. These findings indicate that patients with elevated preoperative NT-proBNP and/or hs-cTnT (and rising postoperative hs-cTnT) warrant closer monitoring for hemodynamic instability and potential prolonged vasoactive/inotropic requirements. However, these are not yet incorporated into formal guidelines for cardiac surgery and remain investigational/prognostic rather than directive for routine screening or management changes. Practical Clinical Considerations • In high-risk valve surgery patients (e.g., advanced age, poor LVEF, atrial fibrillation, high EuroSCORE II), measuring preoperative NT-proBNP and hs-cTnT (with postoperative serial hs-cTnT) may help identify those at greater risk for prolonged inotropic support and guide intensified perioperative care (e.g., optimized preload/afterload management, early mechanical support readiness). • No universal thresholds are guideline-endorsed for this endpoint in cardiac surgery, but studies often highlight elevations well above normal (e.g., preoperative NT-proBNP > several hundred to thousands ng/L; postoperative hs-cTnT peaks in the hundreds to thousands ng/L range). • Future research may lead to integration into cardiac-specific guidelines, similar to how hs-cTn has been adopted for noncardiac surgery risk stratification. In summary, while promising prognostic data exist from dedicated studies on valve surgery patients, current major guidelines do not provide specific recommendations for using these biomarkers to predict prolonged inotropic support or instability in this setting. Clinical judgment, combined with established risk scores and patient-specific factors, remains the mainstay.