Perioperative cardiac risk reduction

Cardiovascular complications are the most common cause of perioperative morbidity and mortality. Noninvasive stress testing is rarely helpful in assessing risk, and for most patients there is no evidence that coronary revascularization provides more protection against perioperative cardiovascular events than optimal medical management. Patients likely to benefit from perioperative beta blockade include those with stable coronary artery disease and multiple cardiac risk factors. Perioperative beta blockers should be initiated weeks before surgery and titrated to heart rate and blood pressure targets. The balance of benefits and harms of perioperative beta-blocker therapy is much less favorable in patients with limited cardiac risk factors and when initiated in the acute preoperative period. Perioperative statin therapy is recommended for all patients undergoing vascular surgery. When prescribed for the secondary prevention of cardiovascular disease, aspirin should be continued in the perioperative period.     

Coronary artery disease in surgical patients. Preoperative evaluation.

Primary care physicians play a major role in the risk stratification of patients with coronary artery disease (CAD) preparing for noncardiac surgery. Preoperative risk assessment takes into account the type and urgency of surgery and the extent of underlying CAD. With this approach, patients can be categorized as being at high, intermediate, or low risk for postoperative cardiac complications. Judicious use of preoperative noninvasive cardiac testing may help identify those patients at particularly high risk for such complications.     

Perioperative risk of patients undergoing noncardiac surgery after coronary artery bypass surgery

BACKGROUND: Most data suggesting that noncardiac surgery early after coronary artery bypass surgery carries low risk are derived from post hoc analyses of randomized controlled trials, with only limited data derived from contemporary, nonselected, and nontrial patients. METHODS: We retrospectively reviewed the medical records of patients who underwent coronary artery bypass surgery at our institution between January 1999 and October 2006 to determine whether they subsequently had major noncardiac surgery and what the outcomes of the noncardiac surgery were. RESULTS: During the study period, 1065 patients underwent coronary artery bypass surgery, and 272 (26%) subsequently underwent 467 major noncardiac surgeries. The mean interval from coronary artery bypass to noncardiac surgery was 1.9 +/- 1.9 years (range, 0-7.8 years). A major complication occurred in 3 surgeries (0.6% [95% confidence interval, 0.1%-1.9%]). Two patients died (both from respiratory arrest during the postoperative period: 1 patient had a tongue cancer excision, and the other patient had polycythemia vera), and the third patient had a perioperative arrhythmia. CONCLUSIONS: Noncardiac surgery is often required early after coronary artery bypass surgery and carries very low risk for cardiac complications, suggesting that preoperative cardiac evaluation may not be required in most such patients.     

Preoperative cardiac risk assessment

Heart disease is the leading cause of mortality in the United States. An important subset of heart disease is perioperative myocardial infarction, which affects approximately 50,000 persons each year. The American College of Cardiology (ACC) and American Heart Association (AHA) have coauthored a guideline on preoperative cardiac risk assessment, as has the American College of Physicians (ACP). The ACC/AHA guideline uses major, intermediate, and minor clinical predictors to stratify patients into different cardiac risk categories. Patients with poor functional status or those undergoing high-risk surgery require further risk stratification via cardiac stress testing. The ACP guideline also starts by screening patients for clinical variables that predict perioperative cardiac complications. However, the ACP did not feel there was enough evidence to support poor functional status as a significant predictor of increased risk. High-risk patients would sometimes merit preoperative cardiac catheterization by the ACC/AHA guideline, while the ACP version would reserve catheterization only for those who were candidates for cardiac revascularization independent of their noncardiac surgery. A recent development in prophylaxis of surgery-related cardiac complications is the use of beta blockers perioperatively for patients with cardiac risk factors.     

Outcome of noncardiac operations in patients with severe coronary artery disease successfully treated preoperatively with coronary angioplasty.

The risk of perioperative myocardial infarction and death was evaluated in 50 patients (mean age, 68 years) with severe coronary artery disease who underwent a noncardiac operation after revascularization had been achieved by successful percutaneous transluminal coronary angioplasty. Before angioplasty, all patients were thought to be at high risk for perioperative complications on the basis of assessment of clinical variables and findings on specialized diagnostic tests. Of the 50 patients, 31 had Canadian Heart Association class III or IV angina or unstable angina. All patients who underwent functional testing had positive results. At catheterization, 38 patients (76%) had multivessel disease. The 50 patients underwent 54 noncardiac operations at a median of 9 days after angioplasty. The overall frequency of perioperative myocardial infarction was 5.6%, and the mortality was 1.9%. Two nonfatal non-Q-wave infarctions and one fatal Q-wave infarction occurred. In patients who have undergone successful angioplasty for severe coronary artery disease, the risk of major cardiac complications associated with a noncardiac surgical procedure is low.     

Perioperative surveillance for adverse myocardial events

Perioperative myocardial infarctions occur in 1 to 4% of unselected noncardiac surgical patients, and are associated with high mortality. Detection of these events can be challenging, because 'typical' symptoms of myocardial ischemia may not be present or may be masked in the perioperative period. Therefore, surveillance by means of intraoperative cardiac monitoring and postoperative serial electrocardiograms (ECGs) and troponins may be needed. Cardiac monitoring not infrequently detects ST-segment changes suggestive of ischemia during or shortly after surgery. To respond to these changes, the risk for coronary artery disease should be assessed before recommending additional interventions. For all vascular surgery patients, and for patients who have or are felt to be at risk for coronary artery disease, serial postoperative 12-lead ECGs and troponins should be considered. Among surgical patients not meeting these criteria, obtaining routine ECGs in the absence of signs or symptoms that suggest a cardiac event may be falsely reassuring and is not felt to be useful. The presence of elevated postoperative troponins predicts worsened prognosis, and argues for intensified risk factor modification. The need for noninvasive cardiac testing or cardiac catheterization should be made on an individual basis.     

Preparation of the cardiac patient for noncardiac surgery

Approximately 20 to 40 percent of patients at high risk of cardiac-related morbidity develop myocardial ischemia perioperatively. The preferred approach to diagnostic evaluation depends on the interactions of patient-specific risk factors, surgery-specific risk factors, and exercise capacity. Stress testing should be reserved for patients at moderate to high risk undergoing moderate- or high-risk surgery and those who have poor exercise capacity. Further cardiovascular studies should be limited to patients who are at high risk, have poor exercise tolerance, or have known poor ventricular function. Medical therapy using beta blockers, statins, and alpha agonists may be effective in high-risk patients. The evidence appears to be the strongest for beta blockers, especially in high-risk patients with proven ischemia on stress testing who are undergoing vascular surgery. Many questions remain unanswered, including the optimal role of statins and alpha agonists, whether or not these therapies are as effective in patients with subclinical coronary artery disease or left ventricular dysfunction, and the optimal timing and dosing regimens of these medications.     

非心脏手术围手术期心脏事件预测的超声心动图研究现状

对非心脏手术病人进行准确的术前心脏事件危险性评估可以帮助临床采取预防性保护措施并制定合理的治疗方案,降低围手术期心脏事件的发生.采用何种合适的术前检测方法和恰当的术前风险评估一直是临床关注的研究热点.超声心动图,特别是负荷超声心动图通过对非心脏病人术前心脏各指标的检测,可以对围手术期心脏事件的危险性进行分级,被认为是有潜在价值的评估非心脏手术病人心脏事件发生的有效方法.     

房颤合并冠状动脉粥样硬化性心脏病的抗栓治疗策略

房颤和冠状动脉粥样硬化性心脏病均为常见疾病。缺血性卒中和系统性血栓栓塞是房颤患者的主要不良预后,抗栓治疗可显著减少血栓栓塞事件风险;另一方面,抗血小板治疗又是冠状动脉粥样硬化性心脏病治疗的关键。当房颤患者合并冠状动脉粥样硬化性心脏病时,需要通过抗凝联合抗血小板治疗以减少卒中及缺血性心脏事件的发生。然而,联合抗栓策略会增加出血并发症的风险。如何平衡出血和血栓风险,以及如何在不同口服抗凝药物和抗血小板药物中进行选择,制定最优的抗栓方案是临床工作面临的挑战。     

Depression, stress and coronary heart disease--epidemiology, prognosis and therapeutic sequelae

Depression and coronary heart disease may be related in several ways: (1) There is epidemiological evidence that high levels of depressive symptoms in male and female patients are associated with an increased risk of myocardial infarction and a higher mortality following an acute cardiac event. Furthermore, patients developing depression after myocardial infarction have more complications, including cardiac arrhythmias. (2) In patients with a chronic coronary heart disease depression also results in a worse cardiac functional status with more frequent and severe chest pain, more physical limitation, less treatment satisfaction and a lower perceived quality of life. Non-compliance with drug therapy is also more prevalent in depressed cardiac patients. (3) The possible pathophysiological mechanisms leading to more frequent complications of coronary heart disease in patients with depression are not fully explained, but could partly be due to higher sympatho-adrenergic stimulation and increased platelet aggregation. Some anti-depressant medications, on the other hand, may also cause cardiac symptoms and increase the risk in patients with coronary heart disease. The use of tricyclic antidepressants has been shown to result in a higher relative risk of myocardial infarction even after adjustment for other cardiovascular risk factors. Tricyclic anti-depressants may have direct cardiac effects, such as QT-prolongation with ventricular arrhythmias, orthostatic hypotension and, less frequently, myocardial dysfunction. In contrast such associations were not found with the newer serotonin re-uptake inhibitors. What are the practical consequences of the observed association between coronary artery disease and depression? First of all depression should better and earlier be recognised also by non-psychiatrists and treatment indications be discussed with specialists. At present, however, there is no clear evidence that ant-depressant drugs or psychotherapy will reduce the risk of myocardial infarction and improve prognosis. Further data are urgently needed to clarify the role of therapeutic interventions. Therefore, a closer research co-operation between cardiologists and psychiatrists should be promoted in future.     

Medical management of stable coronary artery disease

All patients with stable coronary artery disease require medical therapy to prevent disease progression and recurrent cardiovascular events. Three classes of medication are essential to therapy: lipid-lowering, antihypertensive, and antiplatelet agents. Lipid-lowering therapy is necessary to decrease low-density lipoprotein cholesterol to a target level of less than 100 mg per dL, and physicians should consider a goal of less than 70 mg per dL for very high-risk patients. Statins have demonstrated clear benefits in morbidity and mortality in the secondary prevention of coronary artery disease; other medications that can be used in addition to statins to lower cholesterol include ezetimibe, fibrates, and nicotinic acid. Blood pressure therapy for patients with coronary artery disease should start with beta blockers and angiotensin-converting enzyme inhibitors. If these medications are not tolerated, calcium channel blockers or angiotensin receptor blockers are acceptable alternatives. Aspirin is the first-line antiplatelet agent except in patients who have recently had a myocardial infarction or undergone stent placement, in which case clopidogrel is recommended. Anginal symptoms of coronary artery disease can be treated with beta blockers, calcium channel blockers, nitrates, or any combination of these. Familiarity with these medications and with the evidence supporting their use is essential to reducing morbidity and mortality in patients with coronary artery disease.     

Evaluation of coronary artery disease in patients having noncardiac surgery

Perioperative myocardial infarction and cardiac death are feared complications of noncardiac surgery. Preoperative risk assessment begins with clinical variables. There is no formula for determining who needs further evaluation. In selected patients, thallium scintigraphy or coronary arteriography is needed to define preoperative risk.     

Preoperative Cardiac Risk Assessment and Medical Management for Noncardiac Surgery

Advanced practice nurses (APNs) often care for patients who have risks for postoperative cardiac complications and face noncardiac surgery. Surgical urgency determines the initial preoperative evaluation, and the immediate action before emergency surgery is to identify high-risk patients and provide appropriate risk reduction. An elective surgery in those with active cardiac disease should be postponed until cardiac evaluation and treatment are complete. Asymptomatic patients may be risk stratified, and the revised cardiac risk index is easy to use and widely adopted. APNs have the opportunity to assess patient risk and take appropriate actions to minimize cardiac complications.     

Coronary artery disease screening, treatment, and follow-up

Heart disease causes more than 30% of US deaths. Evidence-based screening allows a primary care physician to identify patients at risk before symptom onset. Estimating disease probability before screening affects which tests are appropriate. Low-risk adults should not be screened. ECG, exercise treadmill testing, cardiac stress imaging, electron beam computed tomography, and angiography are possible screening tests. Special populations may have additional screening indications. Management of patients who have coronary artery disease includes antiplatelet therapy; aggressive lipid lowering; management of hypertension with beta blockers and angiotensin-converting enzyme inhibitors; risk factor management, including smoking cessation, diet, and exercise; symptom management; and sometimes revascularization. Primary care physicians are well-suited to the monitoring and care of patients who have known coronary artery disease.     

Cardiac risk factors in patients undergoing noncardiac surgery

Cardiac risks of noncardiac surgery are associated with some noncardiac risk factors but are primarily a function of the patient's underlying cardiac disease. Elective surgery should only be performed when the patient is in optimal condition--i.e., with no evidence of heart failure, at least 6 months after a previous myocardial infarction, and so forth. Careful monitoring of fluid status should lead to reduced cardiac morbidity and mortality after surgery in these patients.     

Does the use of statins improve outcomes in coronary artery bypass graft surgery?

Statins (3-hydroxy-3-methylglutaryl CoA reductase inhibitors) are one of the most frequently prescribed medications throughout the world with beneficial effects that extend beyond their lipid-lowering activity. It has been suggested that statins may offer a simple and cost-effective strategy to reduce some of the complications that occur in association with coronary artery bypass graft (CABG) surgery. Limited existing randomized trial evidence in the setting of cardiac surgery suggests that statins may reduce the incidence of postoperative atrial fibrillation. However, any effect of statins on other outcomes is less clear. The clinical significance of specific statin agent and dose, acute statin withdrawal and the potential benefits associated with statin reloading remain important yet currently unresolved issues. Despite limited high-quality evidence, class I recommendations have been made that all patients undergoing coronary artery bypass graft surgery should receive statin therapy unless contraindicated.     

Perioperative myocardial ischemic episodes are related to hematocrit level in patients undergoing radical prostatectomy

BACKGROUND: The anemia associated with perioperative blood conservation has raised concerns regarding the safety of these strategies in patients with ischemic cardiovascular disease. Therefore the relationship between hematocrit level and myocardial ischemic episodes in a group of elderly patients undergoing elective noncardiac surgery was studied. STUDY DESIGN AND METHODS: One hundred ninety patients undergoing radical prostatectomy were randomly assigned to one of three blood conservation groups: preoperative autologous blood donation, acute normovolemic hemodilution, and preoperative erythropoietin therapy with acute normovolemic hemodilution. Patients underwent ambulatory electrocardiography monitoring to evaluate for myocardial ischemia at randomization (baseline), 7 days preoperatively, throughout surgery, and for 24 hours after surgery. RESULTS: Myocardial ischemic episodes occurred in 61 (34%) of 181 evaluable patients. Patients with hematocrit levels < 28 percent immediately after surgery were significantly (p = 0.05) more likely to have intraoperative and postoperative ECG ischemic episodes. Intraoperative ischemia and tachycardia correlated (r = 0.21, p = 0.008) with hematocrit levels. Hematocrit levels after surgery were associated with postoperative ischemia (r = 0.14, p = 0.03) and duration of myocardial ischemic episodes (r = 0.14, p = 0.04). After adjusting for other risk factors, intraoperative tachycardia episodes, hematocrit level < 28 percent immediately after surgery, and risk factors for coronary artery disease were independently associated with the likelihood of intraoperative ischemia (r = 0.36, p = 0.002, area under receiver operating characteristic curve = 0.73). Similarly, tachycardia episodes and hematocrit levels < 28 percent immediately after surgery were independently associated with ischemic episodes during the first postoperative day (r = 0.30, p = 0.004, area under receiver operating characteristic curve = 0.71). CONCLUSION: A hematocrit level < 28 percent is independently associated with risk for myocardial ischemia during and after noncardiac surgery. Avoidance of cardiac complications may require higher transfusion thresholds, closer attention to tachycardia, or better monitoring for ischemia.     

Prevalence of leg wound complications after coronary artery bypass grafting: determination of risk factors.

BACKGROUND: The reported prevalence of leg wound complications after coronary artery bypass grafting is 2% to 24%. Decreased length of hospital stay for patients who have this surgical procedure poses new care requirements in both acute care and community settings. OBJECTIVE: To determine the prevalence of postoperative leg wound complications in patients undergoing coronary artery bypass grafting and the risk factors associated with these complications. METHOD: In this prospective, observational study, 547 consecutive patients who had coronary artery bypass grafting alone or in combination with other cardiac surgical procedures were examined for evidence of leg wound complications each day after surgery during hospitalization. After discharge, problems were detected by home care nurses. RESULTS: The prevalence of leg wound complications was 6.8%. Factors significant by multiple logistic regression included preoperative hospitalization, use of an Ace elastic bandage in the operating room, the length of time the leg incision remained open in the operating room, and administration of nicardipine intravenously in the intensive care unit. Odds ratios were calculated for each variable. Premorbid factors such as diabetes or peripheral vascular disease were not predictive of complications. On average, most problems occurred on postoperative day 10, when many patients were at home. CONCLUSIONS: The results highlight the need to detect complications early, in both the hospital and the community settings. The determination of factors related to poor outcomes may assist clinicians in improving healthcare delivery.     

Exercise and hypertension. Maximizing the benefits in patients receiving drug therapy.

Aerobic exercise may prevent hypertension and reduce blood pressure and mortality in hypertensive patients and those at high risk for coronary artery disease. Supervised aerobic exercise at an intensity of 70% to 80% of maximal aerobic capacity is recommended to achieve cardiovascular conditioning and other health benefits. When antihypertensive drug therapy is required, physicians should choose an agent that has favorable secondary effects, including hemodynamic responses to exercise. The most favorable effects are achieved with calcium channel blockers, angiotensin-converting enzyme inhibitors, alpha blockers, and central alpha agonists. The effects of diuretics are less desirable, and beta blockers should be a last choice for hypertensive patients who are physically active.     

Chronic stable angina pectoris. Risk stratification and treatment.

Workup of stable angina patients begins with careful history taking and evaluation of various risk factors, physical examination, and a resting electrocardiogram (ECG). A noninvasive exercise stress test is valuable for risk stratification. Abnormalities on a resting ECG or equivocal results on a stress test warrant an exercise test combined with thallium scintigraphy, which is more sensitive and specific. Cardiac catheterization is advisable for patients with chest discomfort and multiple risk factors, even if results of thallium testing are negative. Patients with severe or progressive angina or congestive heart failure should also have cardiac catheterization. Nitrates, beta-adrenergic blockers, and calcium channel blockers are cornerstones of medical therapy. Revascularization with coronary artery bypass graft is recommended for patients with left main coronary artery disease, left ventricular dysfunction, or severe proximal three-vessel coronary artery disease. Percutaneous transluminal coronary angioplasty (PTCA) is a good alternative for one- or two-vessel disease. Three-vessel PTCA can be accomplished, but its real role still remains to be established.