Effects of Low-dose Esmolol on Myocardial Injury After Non-cardiac Surgery in Elderly Frail Patients

This topic will focus on the following questions:Part one: To clarify the relationship between preoperative frailty and myocardial injury (cTnT ≥0.03) after non-cardiac surgery in elderly patients; To further explore the predictive factors of myocardial injury after non-cardiac surgery （MINS） in elderly frail patients before operation.Part Two: To explore the effect of low-dose esmolol on myocardial injury after non-cardiac surgery in frail elderly patients.

Inclusion Criteria:Age ≥ 65 years;ASA: ⅰ-ⅳ;Modified frailty index (mFI) ≥ 0.21;Patients undergoing non-cardiac surgery.Exclusion Criteria:Refuse to participate;Expected hospital stay <3 days;Preoperative β-blocker therapy;History of myocardial infarction or coronary artery disease;Preoperative bradycardia (heart rate [HR] < 50 bpm) or arrhythmia;Significant cardiac insufficiency (i.e., pulmonary artery pressure >18 mm Hg, cardiac index ≤ 2.2 L/min/m 2);Severe valvular heart disease;Severe lung disease (e.g. asthma or chronic obstructive pulmonary disease);Patients with perioperative troponin elevation due to nonischemic causes (e.g., sepsis, pulmonary embolism, arrhythmia);The same patient can only be included once, regardless of whether the reason for the second operation is related to the first cause.-