From the Guidelines
Perioperative myocardial injury assessment should prioritize cardiac troponin measurement, with high-sensitivity troponin T or I recommended at baseline and postoperative periods, as it is associated with adverse short- and long-term outcomes, including a high 30-day mortality rate of approximately 10% 1. The assessment of perioperative myocardial injury is crucial in noncardiac surgery, as it occurs in approximately 20% of patients and is associated with significant morbidity and mortality. Key aspects of assessment include:
- Cardiac troponin measurement: This is the cornerstone of diagnosis, with a rise in troponin above the 99th percentile upper reference limit indicating myocardial injury 1.
- Clinical evaluation: Symptoms like chest pain, dyspnea, or hemodynamic instability should be assessed, although many cases of perioperative myocardial injury are clinically silent.
- Imaging techniques: 12-lead ECG monitoring and echocardiography should be used to detect ST-segment changes, T-wave inversions, or new-onset arrhythmias, and to evaluate wall motion abnormalities, ejection fraction, and valvular function, respectively.
- Risk stratification: Tools like the Revised Cardiac Risk Index can help identify patients requiring more intensive monitoring. The pathophysiology of perioperative myocardial injury involves both supply-demand mismatch and acute coronary thrombosis, triggered by surgical stress, catecholamine surges, inflammation, and hypercoagulability 1. Early detection of perioperative myocardial injury is crucial, as it significantly increases 30-day mortality, even when asymptomatic, with a population attributable risk of 30-day postoperative mortality of 34% 1.
From the FDA Drug Label
DOSAGE & ADMINISTRATION Myocardial Infarction Early Treatment During the early phase of definite or suspected acute myocardial infarction, initiate treatment with metoprolol tartrate as soon as possible after the patient’s arrival in the hospital. In patients who tolerate the full intravenous dose (15 mg), initiate metoprolol tartrate tablets, 50 mg every 6 hours, 15 minutes after the last intravenous dose and continued for 48 hours.
The assessment of perioperative myocardial injury is not directly addressed in the provided drug label for metoprolol tartrate. However, the label does discuss the treatment of myocardial infarction in the early phase, which may be relevant to the assessment of myocardial injury in a perioperative setting.
- The label recommends initiating treatment with metoprolol tartrate as soon as possible after the patient's arrival in the hospital.
- It also emphasizes the importance of monitoring blood pressure, heart rate, and electrocardiogram during intravenous administration of metoprolol tartrate injection.
- The label provides guidance on dosage and administration, including the use of intravenous and oral formulations, but does not specifically address the assessment of perioperative myocardial injury. Based on the information provided, it appears that metoprolol tartrate may be used to treat myocardial infarction, but the label does not provide direct guidance on assessing perioperative myocardial injury 2.
From the Research
Assessment of Perioperative Myocardial Injury
- Perioperative myocardial injury, also known as myocardial injury after non-cardiac surgery (MINS), is a frequent complication of surgical patients after having non-cardiac surgery that is strongly associated with perioperative mortality 3.
- MINS is defined as an elevation in troponin concentrations within 30 days postoperatively, and although typically asymptomatic, patients with MINS suffer myocardial damage and have a 10% risk of death within 30 days after surgery and excess risks of mortality that persist during the first postoperative year 3.
- The assessment of perioperative myocardial injury involves the use of high-sensitivity cardiac troponin T (hs-cTnT) to predict major adverse cardiovascular and cerebrovascular events (MACCE) and mortality, with a perioperative increase in hs-cTnT ≥14 ng L-1 above preoperative values providing statistically optimal model performance 4.
Risk Stratification and Prevention
- Risk stratification for MINS can be improved by the addition of biomarkers for ischemia, left ventricular function, and atherosclerosis to classic cardiac risk factors, as well as the use of intraoperative monitoring techniques such as continuous 12-lead ECG assessment and transesophageal echocardiography 5.
- A prudent perioperative beta-blocker and statin regimen can reduce cardiac complications and mortality without increasing the risk of stroke in intermediate to high-risk patients 5.
- Automated preoperative assessment of endothelial dysfunction using reactive hyperaemia-peripheral arterial tonometry (RH-PAT) index can provide effective risk stratification for MINS, with endothelial dysfunction being associated with MINS and increased time to discharge from hospital after surgery 6.
Management and Treatment
- Managing patients with MINS postoperatively includes minimizing triggers (such as hemodynamic abnormalities and anemia) that can continue the damage, as well as the use of long-term pharmacologic strategies such as beta-blockers, statins, antiplatelet agents, and anticoagulation 7.
- A multidisciplinary approach, that includes involvement of anesthesiologists, is recommended for the prevention, diagnosis, and treatment of MINS 7.