الفهرس 
Physiology of the heartOnly 14 pages are availabe for public view
 |  | from | 119 |  |  |
| | | from | 119 | | |
Abstract
Myocardial infarction is the major cause of perioperative morbidity and mortality. The pathophysiology of PMI is related to the stress of surgery, inducing an oxygen supply/demand imbalance in the presence of a coronary artery stenosis or a sudden coronary plaque rupture with thrombosis and vessel occlusion.
Comprehensive preoperative evaluation and appropriate therapy may significantly improve periprocedural and long-term outcomes. Indications for preoperative cardiac testing are the same as in the nonoperative setting, but their timing is dependent on several factors, including the urgency of noncardiac surgery, patient-specific risk factors, and surgery-specific considerations. The use of both noninvasive and invasive preoperative testing should be limited to those circumstances in which the results of such tests will clearly affect patient management, for many patients, noncardiac surgery represents their first opportunity to receive an appropriate assessment of both short- and long-term cardiac risk, thus lowering the immediate perioperative cardiac risk, as well as assessing the need for subsequent postoperative risk stratification and interventions directed at modifying coronary risk factors.
The ACCF/AHA focused update on perioperative beta-blockers incorporates important new information regarding the risks and benefits of perioperative beta-blockers. In this update, a Class I indication for perioperative beta-blocker use exists, for continuation of a beta-blocker in patients already taking the drug. In addition, several Class IIa recommendations exist for patients with inducible ischemia, coronary artery disease, or multiple clinical risk factors who are undergoing vascular (i.e., high-risk) surgery and for patients with coronary artery disease or multiple clinical risk factors who are undergoing intermediate-risk surgery.
Initiation of beta-blockers therapy, particularly in lower-risk groups, requires careful consideration of the risk:benefit ratio for an individual patient. Initiation well before a planned procedure with careful titration perioperatively to achieve adequate heart rate control while avoiding frank bradycardia or hypotension is also suggested. In light of the POISE results, routine administration of perioperative beta-blockers, particularly in higher fixed-dose regimens started on the day of surgery, cannot be advocated.