In the last 10 years, there has been a growing body of literature regarding the prevention of perioperative cardiac complications with important strides toward minimizing postoperative cardiac events. That said, cardiac complications do occur, and this chapter addresses their demographics, risk factors, and management. It is divided into sections of postoperative myocardial infarction, congestive heart failure, atrial fibrillation, and ventricular arrhythmias.
The combination of an aging, comorbid population with the rapid increase in surgical procedures has resulted in perioperative myocardial infarction (PMI) becoming a common and unfortunate reality. The incidence of PMI is dependent upon patient risk factors, the type of surgery, and the definition of MI. An early review of PMI in an unselected group of patients over the age of 40 years uncovered PMI rate of 1.4% compared to a 6.9% rate in patients selected for preoperative cardiac testing, presumably a higher-risk cohort. The largest study to date of operative cardiac outcomes, the PeriOperative Ischemic Evaluation (POISE) trial, found a 30-day MI rate of 5.7% in the control group undergoing noncardiac surgery. Meanwhile, the Coronary Artery Revascularization Prophylaxis (CARP) trial included a cohort of high-risk patients with known coronary artery disease undergoing vascular surgery and noted that 27% of patients experienced a postoperative troponin elevation. The overall risk and consequences of PMI are dependent upon patient- and procedure-related risk factors and it is thus imperative to risk assess (covered in Chapter 51), recognize, and appropriately manage PMI.
Perioperative MI was traditionally difficult to diagnose because the key biomarker, creatinine kinase-MB is routinely elevated in postoperative patients due to skeletal muscle trauma. Additionally, the key symptom of chest pain is often masked at least partially by anesthesia, analgesia, and sedation. Furthermore, electrocardiograms (ECGs) are infrequently obtained, missing subtle or transient changes. As a result, PMI was routinely overlooked or not recognized until complications occurred, often as late as postoperative day 5. This played a significant role in the traditionally high rates of morbidity and mortality of PMI. Short-term mortality with PMI is directly correlated to the level of troponin elevation and ranges from 3.5 to 25%. Moreover, even postoperative troponin leak negatively impacts long-term survival.
The advent of troponin testing, sensitive and specific for myocardial injury, greatly enhances the ability to diagnose PMI. Coupling a rise of cardiac biomarkers with signs of myocardial ischemia—such as consistent symptoms, ECG changes, or findings on coronary imaging—allows PMI to be reliably diagnosed. Most PMIs occur within 24 hours of surgery, but about 10% occur more than 1 day postoperatively. The reasons for this dichotomy can be explained by the two different mechanisms of PMI.
Postoperative MI usually occur within 24 hours of surgery but about 10% occur more than 1 day postoperatively.
- Short-term mortality is directly correlated to the level of troponin ...
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