Assessment of Cardiac Function and Anesthesia Depth in Patients Undergoing Cardiac Surgery

The SHAPE study is a prospective, randomized, parallel‐group, single‐maskedinterventional study conducted in adult patients undergoing elective cardiac surgery withcardiopulmonary bypass. The study is designed to investigate perioperative changes inmyocardial function and to assess the potential influence of anesthesia depth on thesechanges.Participants are randomized in a 1:1 ratio to two Bispectral Index (BIS)‐guidedanesthesia strategies: a BIS target of 45‐55, representing standard anesthesia depth, ora BIS target of 30‐35, representing deeper anesthesia. Total intravenous anesthesia withpropofol and remifentanil is adjusted by the treating anesthesiologist to maintain theassigned BIS range. The echocardiographic outcome assessor remains blinded to treatmentallocation during image acquisition, offline echocardiographic analysis, and primaryoutcome assessment.Cardiac function is evaluated using transthoracic echocardiography and speckle‐trackinganalysis. Measurements include left ventricular global longitudinal strain (LV GLS),myocardial work indices, and additional indices of left‐ and right‐sided cardiacfunction. Invasive hemodynamic monitoring using a Swan‐Ganz catheter providesmeasurements including pulmonary capillary wedge pressure, cardiac output, cardiac index,pulmonary artery pressure, and right atrial pressure.The primary analysis evaluates the within‐participant change in LV GLS between twopredefined intraoperative time points: after induction of anesthesia and beforeinitiation of cardiopulmonary bypass (T1), and after separation from cardiopulmonarybypass (T2). Secondary analyses will assess whether the magnitude of perioperativechanges in LV GLS and myocardial work differs between the two randomized BIS groups andwill explore associations between echocardiographic measurements, invasive hemodynamicparameters, and postoperative clinical outcomes.Postoperative outcomes include low cardiac output syndrome, requirement for inotropic orvasopressor support, postoperative atrial fibrillation, duration of mechanicalventilation, and length of intensive care unit stay. Echocardiographic follow‐up isperformed at 3, 6, and 12 months after surgery to assess longer‐term changes in cardiacfunction.