Evaluation of primary care patients with chronic stable angina: guidelines from the American College of Physicians

In 1999, the American College of Physicians (ACP), then the American College of Physicians-American Society of Internal Medicine, and the American College of Cardiology/American Heart Association (ACC/AHA) developed joint guidelines on the management of patients with chronic stable angina. The ACC/AHA then published an updated guideline in 2002, which the ACP recognized as a scientifically valid review of the evidence and background paper. This ACP guideline summarizes the recommendations of the 2002 ACC/AHA updated guideline and underscores the recommendations most likely to be important to physicians seeing patients in the primary care setting. This guideline is the first of 2 that will provide guidance on the management of patients with chronic stable angina. This document will cover diagnosis and risk stratification for symptomatic patients who have not had an acute myocardial infarction or revascularization procedure in the previous 6 months. Sections addressing asymptomatic patients are also included. Asymptomatic refers to patients with known or suspected coronary disease based on history or on electrocardiographic evidence of previous myocardial infarction, coronary angiography, or abnormal results on noninvasive tests. A future guideline will cover pharmacologic therapy and follow-up.     

Utilization of coronary angiography and revascularization after acute myocardial infarction in men and women risk stratified by the American College of Cardiology/American Heart Association guidelines

OBJECTIVES: We sought to determine whether men and women are equally likely to receive coronary angiography and revascularization after acute myocardial infarction (AMI) when they are risk stratified according to American College of Cardiology/American Heart Association (ACC/AHA) practice guidelines for post-MI care. BACKGROUND: Several previous studies have suggested that women may undergo angiography and revascularization procedures less frequently than men. METHODS: In 439 consecutive patients admitted to a public hospital with AMI, rates of coronary angiography and revascularization were compared in men and women categorized, according to ACC/AHA practice guidelines, as having strong (class I or IIa) or weaker (class IIb) indications for angiography. RESULTS: Women were older and more likely to be diabetic or hypertensive, but men and women were equally likely to meet class I/IIa criteria for post-MI angiography (both 51%). Angiography rates were nearly identical in men and women overall (63% vs. 64%), as well as in patients in class I/IIa (80% vs. 82%) and class IIb (46% vs. 46%) (all p > 0.80, with >80% power to detect important differences); the only multivariate predictors of post-MI angiography were age and ACC/AHA class. Significant coronary artery disease was equally prevalent in men and women undergoing angiography, and men and women were equally likely to undergo revascularization, whether they were in class I/IIa (both 55%, p = 0.90) or class IIb (59% vs. 58%, p = 0.88). No significant differences in mortality were noted between men and women. CONCLUSIONS: Despite being older and having more risk factors than men, women were equally likely to undergo coronary angiography and revascularization procedures after AMI, and they had in-hospital clinical outcomes that were at least as favorable.     

Management of Stable Angina – Current Guidelines: A Critical Appraisal

Guidelines provide recommendations to improve patient outcomes, but many of the recommendations made for treating patients with stable angina are opinion based rather than evidence based. Risk stratification to predict patients at an increased risk of myocardial infarction (MI) and sudden ischemic death, and selection of patients for possible revascularization, is based on expert opinion. Randomized trials have compared optimal medical therapy to revascularization, after the coronary anatomy was known, and yet routine coronary angiography to exclude left main disease is not recommended. What exactly is optimal antianginal treatment varies considerably from one country’s guideline recommendations to another. None of the antianginal drugs reduce mortality or MI and these drugs are equally effective in treating angina pectoris; and yet beta-blockers and calcium channel blockers are recommended as first line therapy. Double and triple therapy with different classes of antianginal drugs is also expert opinion based rather than evidence based. Recommendations to reduce the incidence of MI and sudden death are appropriate; however the use of a potent, high dose statin, is recommended by AHA/ACC and NICE guidelines for all patients with ischemic heart disease, while the European guidelines recommend a target LDL goal in patients with coronary artery disease (CAD). Management of patients with stable angina pectoris with normal coronary arteries remains ambiguous. This short review critically appraises the recommendations for managing patients with stable angina pectoris.     

Outcome of patients with significant coronary stenosis but without ischemic evidence on exercise myocardial perfusion scintigraphy

OBJECTIVES: The rates of cardiac events and coronary revascularization were evaluated in patients with significant coronary stenosis of more than 75% by the American Heart Association (AHA) classification but no ischemic evidence by exercise myocardial perfusion scintigraphy. METHODS: Subjects were 171 patients (113 males, 58 females, mean age 66 +/- 9 years) undergoing coronary angiography and without scintigraphic evidence of myocardial ischemia. They were divided into two groups according to the severity of coronary artery stenosis based on AHA classification. Group A was composed of 139 patients with more than 75% stenosis (101 patients with 75% stenosis and 38 patients with more than 90% stenosis), and Group B was composed of 32 patients with 50% stenosis. Cardiac events including angina pectoris (n = 63), myocardial infarction (n = 1), heart failure (n = 2) and cardiac death (n = 0), coronary revascularization and predictive factors were evaluated during follow-up of 34 +/- 21 months. Furthermore, the interval between coronary revascularization and exercise myocardial perfusion scintigraphy was estimated. RESULTS: The rates of cardiac events (45%) and coronary revascularization (29%) in Group A were significantly higher than the rate of cardiac events (9%, p < 0.05) and coronary revascularization (6%, p < 0.05) in Group B. Only percentage stenosis and the number of diseased vessels affected the rates of cardiac event and coronary revascularization. CONCLUSIONS: Patients with significant coronary stenosis, but without ischemic evidence by exercise myocardial perfusion scintigraphy, have a relatively high rate of cardiac event and coronary revascularization, especially in patients with severe stenosis or multivessel disease. However, coronary revascularization should not be performed in all patients with significant coronary stenosis.     

Stable ischemic heart disease in the older adults

Ischemic heart disease (IHD) is caused by atherosclerotic and/or thrombotic obstruction of coronary arteries. Clinical spectrum of IHD expands from asymptomatic atherosclerosis of coronary arteries to acute coronary syndromes (ACS) including unstable angina, acute myocardial infarction (non-ST elevation myocardial infarction and ST elevation myocardial infarction). Stable IHD (SIHD) refers to patients with known or suspected IHD who have no recent or acute changes in their symptomatic status, suggesting no active thrombotic process is underway. These patients include those with i) recent-onset or stable angina or ischemic equivalent symptoms, such as dyspnea or arm pain with exertion; ii) post-ACS stabilized after revascularization or medical therapy; and iii) asymptomatic IHD diagnosed by abnormal stress tests or imaging studies. This review summarizes clinical features and management of SIHD in the older adult. ACS in older adults is not considered in this review.     

Revascularization among patients with acute myocardial infarction complicated by cardiogenic shock and impact of American College of Cardiology/American Heart Association guidelines

Using New York City hospital discharge data from 1995 to 2002, we examined revascularization use among patients who had acute myocardial infarction complicated by cardiogenic shock before and after publication of recommendations by the American College of Cardiology/American Heart Association (ACC/AHA). The modest increase in these procedures from 1995 to 1999 and from 2000 to 2002 most likely reflected a trend, not a response, to the ACC/AHA recommendation. Moreover, the increase appeared to have been due to more frequent admission of eligible patients to hospitals capable of the service, as opposed to increasing revascularization rates in hospitals capable of revascularization.     

Prognostic significance of asymptomatic coronary artery disease in patients with diabetes and need for early revascularization therapy.

AIMS: Information on the clinical outcome of patients with diabetes with silent myocardial ischaemia is limited. We compared the clinical and angiographic characteristics, and the clinical outcomes of diabetic patients with asymptomatic or symptomatic coronary artery disease (CAD). METHODS: Three hundred and ten consecutive diabetic patients with CAD were divided into two groups according to the presence of angina and followed for a mean of 5 years. Fifty-six asymptomatic patients with a positive stress test and CAD on coronary angiography were compared with 254 symptomatic patients, 167 with unstable angina and 87 with chronic stable angina. RESULTS: Although the severity of coronary atherosclerosis was similar in asymptomatic and symptomatic patients, revascularization therapy was performed less frequently in the asymptomatic than the symptomatic patients (26.8 vs. 62.0%; P < 0.001). Asymptomatic patients experienced a similar number of major adverse cardiac events (MACEs; death, non-fatal myocardial infarction, and revascularization; 32 vs. 28%; P = 0.57), but had higher cardiac mortality than symptomatic patients (26 vs. 9%; P < 0.001). However, patients who underwent revascularization therapy at the time of CAD diagnosis in these two groups showed similar MACE and cardiac mortality (20.0 vs. 22.5%, 6.7 vs. 5.3%, respectively; all P > 0.05). CONCLUSIONS: This study suggests that diabetic patients with asymptomatic CAD have a higher cardiac mortality risk than those with symptomatic CAD, and that lack of revascularization therapy may be responsible for the poorer survival.     

Usefulness of fractional flow reserve measurements to defer revascularization in patients with stable or unstable angina pectoris, non-ST-elevation and ST-elevation acute myocardial infarction, or atypical chest pain

This study determined the safety of deferring coronary revascularization based on a fractional flow reserve (FFR) value > or = 0.75 in a series of consecutive unselected coronary patients with moderate coronary lesions, including patients with unstable angina, myocardial infarction (MI), and/or positive noninvasive test findings. The study included 201 consecutive coronary patients (mean age 62 +/- 10 years; 65% men) with 231 lesions evaluated by FFR measurement for which revascularization was deferred based on a FFR value > or = 0.75. Lesions associated with a positive noninvasive test result were those located in an artery supplying a myocardial territory in which myocardial ischemia was demonstrated by a noninvasive test. Cardiac events (cardiac death, MI, revascularization) and Canadian Cardiovascular Society angina class were evaluated at follow-up. Indications for coronary angiography included unstable angina or MI (62%), stable angina (30%), or atypical chest pain (8%). Forty-four patients (22%) had > or = 1 coronary lesion associated with a positive noninvasive test result in which FFR was evaluated. Mean FFR value was 0.87 +/- 0.06 and mean lesion percent diameter stenosis was 41 +/- 8%. At 11 +/- 6 months of follow-up, cardiac events occurred in 20 patients (10%), and no significant differences were observed between patients with unstable angina or MI and those with stable angina (9% vs 13%, p = 0.44) or between patients with and without lesions associated with positive noninvasive test results (9% vs 10%, p = 1.00). At the end of follow-up, 88% of patients were asymptomatic in angina class 0 or I, with no differences across various groups. In conclusion, these results suggest that patients with moderate coronary lesions can be safely managed without revascularization on the basis of FFR measurements, irrespective of clinical presentation and/or presence of positive noninvasive test results.     

Prognostic value of normal adenosine-stress cardiac magnetic resonance imaging

We investigated the prognostic value of normal adenosine stress cardiac magnetic resonance (CMR) in suspected coronary artery disease (CAD). Prospectively enrolled in the study were 218 patients with suspected CAD, no stress hypoperfusion, and no delayed enhancement in CMR, and consecutively deferred coronary angiography. The primary end point was a 12-month rate of major adverse cardiac events (MACE; cardiovascular mortality, myocardial infarction, revascularization, hospitalization due to cardiovascular event). CMR indication was symptomatic angina (Canadian Cardiovascular Society II in 42% and III in 7%) or evaluation of myocardial ischemia in patients with arrhythmia, syncope, and/or equivocal stress tests and cardiovascular risk factors (51%). As the main result, the 12-month MACE rate was 2/218 (1 stent implantation, 1 bypass surgery) and CMR negative predictive value 99.1%. There was no cardiac death or myocardial infarction. In conclusion, normal adenosine stress CMR predicts a very low MACE rate and an excellent 1-year prognosis in patients with suspected CAD. Our results provide clinical reassurance that patients at risk for CAD-associated MACE were not missed by CMR. Hence, CMR may serve as a reliable noninvasive gatekeeper to reduce the number of redundant coronary angiographies.     

Silent ischemia predicts infarction and death during 2 year follow-up of unstable angina

Silent myocardial ischemia as detected on Holter electrocardiographic (ECG) monitoring is present in greater than 50% of patients with unstable angina despite intensive medical therapy. The presence and the extent of silent ischemia have been correlated with an increased risk of early (1 month) unfavorable outcome including myocardial infarction and need for coronary revascularization for persistent symptoms. Seventy patients with unstable angina who had undergone continuous ECG monitoring for silent ischemia were followed up for 2 years; 37 patients (Group I) had Holter ECG evidence of silent ischemia at bed rest in the coronary care unit during medical treatment with nitrates, beta-receptor blockers and calcium channel antagonists; the other 33 patients (Group II) had no ischemic ST segment changes (symptomatic or silent) on Holter monitoring. Over a 2 year follow-up period, myocardial infarction occurred in 10 patients in Group I (in 2 it was fatal) compared with one nonfatal infarction in Group II (p less than 0.01 by Kaplan-Meier analysis); revascularization with either coronary bypass surgery or angioplasty for symptomatic ischemia was performed in 11 Group I and 5 Group II patients (p less than 0.05). Multivariate Cox's hazard analysis demonstrated that the presence of silent ischemia was the best predictor of 2 year outcome. Therefore, persistent silent myocardial ischemia despite medical therapy in patients with unstable angina carries adverse prognostic implications that persist over a 2 year period.     

血浆氨基末端脑钠肽前体水平评价冠心病严重程度的价值

目的观察冠心病患者血浆氨基末端脑钠肽前体(NT-proBNP)水平变化,探讨血浆NT-proBNP水平评价冠心病严重程度价值。方法选择住院治疗,并行冠状动脉造影的患者205例,LVEF 75%共182例,分为急性心肌梗死(AMI)组(41例),不稳定性心绞痛(UAP)组(85例),稳定性心绞痛(SAP)组(40例)和正常组(16例);又根据冠状动脉造影分为单支病变组(52例)、双支病变组(49例)、多支病变组(64例)和零支病变组(40例)。采用Gensini积分法评价冠状动脉病变的狭窄严重程度,测定血浆NT-proBNP水平以及LVEF。结果AMI组和UAP组血浆NT-proBNP水平明显高于SAP组和正常组(P<0.05)。单支病变组、双支病变组和多支病变组血浆NT-proBNP水平明显高于零支病变组(P<0.05)。血浆NT-proBNP水平与LVEF呈负相关,与Gensini积分呈正相关。结论AMI和UAP患者血浆NT-proBNP水平明显升高,可能是冠心病危险分层的有效指标。     

Comparison of silent and symptomatic ischemia during exercise testing in men

OBJECTIVE: To compare angina and ST-segment depression during exercise testing, as markers for coronary artery disease. DESIGN: Retrospective analysis of exercise test responses and cardiac catheterization results. SETTING: A U.S. Veterans Affairs medical center. PATIENTS: Four hundred and sixteen men who were referred for the evaluation of symptoms, postmyocardial infarction testing, or both. Two hundred patients had no clinical or electrocardiographic evidence of previous myocardial infarction, whereas 216 were survivors of a previous myocardial infarction. INTERVENTIONS: All patients did a standard exercise test and had diagnostic coronary angiography with ventriculography within an average of 32 days (range, 0 to 90 days) of their exercise test. RESULTS: Two hundred patients without a previous myocardial infarction were divided into four groups: the no ischemia group had 80 patients; the angina pectoris only group had 23 patients; the silent ischemia group had 40 patients; and the ST-segment depression and angina pectoris group had 57 patients. In patients without a previous myocardial infarction, exercise-induced ST-segment depression was a better marker than exercise-induced angina for the presence of any coronary artery disease (P less than 0.005). Patients with symptomatic exercise-induced ischemia had a higher prevalence of severe coronary artery disease than did those with only silent ischemia (30% compared with 20%; 95% CI, - 7.3% to 27.0%; P = 0.005). For the 216 survivors of a myocardial infarction, divided into the same four groups, ST-segment depression again was a better marker for the presence of severe coronary artery disease compared with angina alone (P = 0.08). The prevalence rates of severe coronary artery disease in the no ischemia plus myocardial infarction group, the angina pectoris only plus myocardial infarction group, the silent ischemia plus myocardial infarction group, and the ST-segment depression and angina pectoris plus myocardial infarction group were 10%, 9%, 23%, and 32%, respectively (P less than 0.01). CONCLUSIONS: Exercise-induced ST-segment depression is a better marker for coronary artery disease than is exercise-induced angina. Symptomatic ischemia during the exercise test is a better marker for severe coronary artery disease than is silent ischemia.     

The predictive value of silent ischemia at an exercise test before discharge after an episode of unstable coronary artery disease. RISC Study Group.

The prognostic value of silent ischemia during a symptom-limited predischarge exercise test (ET) was evaluated in 740 men after an episode of unstable angina or non-Q wave myocardial infarction. The 51% of patients with ST depression at the ET had a higher rate of myocardial infarction or death after 1 year (18%) compared with those without ST depression (9%; p less than 0.01). This increased risk was not influenced by the presence or absence of pain at the ET: 18.3% in patients with painful ischemia compared with 18.1% in patients with silent ischemia. However, ST depression combined with pain at the ET predicted a higher incidence of class III or IV angina at follow-up (43.9% compared with 16.7% in the group with asymptomatic ST depression; p less than 0.001). Because revascularization in addition to alleviating symptoms also enhances the prognosis in certain groups of patients, selections for coronary angiography and possible revascularization should not be made only on the basis of symptoms but also on the presence of myocardial ischemia, whether symptomatic or not.     

Guideline chaos: conflicting recommendations for preoperative cardiac assessment

The American College of Cardiology/American Heart Association (ACC/AHA) and the American College of Physicians (ACP) have disseminated guidelines to assess preoperative cardiac risks before noncardiac surgery. The objectives of this study were to determine if these guidelines differ in preoperative recommendations for a group of patients, and whether these recommendations differ from actual provider recommendations. In this retrospective cohort study, patient characteristics and physician recommendations were abstracted from electronic medical records of consecutive patients attending a Veteran Affairs medical preoperative evaluation clinic from January 1 to April 1, 1998. Patient characteristics were used to determine what preoperative cardiac testing should have been ordered if each guideline was followed. Possible recommendations included operation without testing (OWT), noninvasive stress testing (NST), cardiac catheterization (CC), or cancel or delay surgery (OTHER). Recommendations were compared using statistical tests for agreement. Of the 138 patients identified, most underwent moderate-risk surgeries. Recommendations for preoperative testing were discordant between guidelines for 17% of patients (kappa = 0.38). Guidelines never agreed on the need for NST. Extreme differences in recommendations (i.e., one recommends OWT, the other CC) occurred in 9 patients (7%). Physicians ordered NST more often (n = 27) than either guideline. In this subgroup of patients where providers ordered a NST, the 2 guidelines significantly differed (kappa = 0.26). When applied to real patients being evaluated for surgery, ACC/AHA and ACP guidelines significantly differed in recommendations for preoperative cardiac testing. Results have implications for implementation, management, and practitioner adherence to published guidelines.     

Stabile Angina pectoris

Against the background of a variety of international guidelines and a national disease management program for patients with coronary heart disease, a national health-care guideline for the management of patients with chronic ischemic heart disease ("Nationale VersorgungsLeitlinie Chronische KHK [NVL KHK]") was first published in Germany in 2006. This guideline is an interdisciplinary initiative of several German health-care authorities and medical societies.Because of the limited diagnostic sensitivity of about 70% only, and a high percentage of patients, who are unable to exercise, a negative stress ECG can definitely not exclude hemodynamically significant coronary heart disease. Therefore, the well-known evidence-based algorithms of the American College of Cardiology/American Heart Association (ACC/AHA) guidelines for noninvasive stress testing and complementary stress imaging were newly adopted by the NVL KHK. In flow charts for patients with suspected or already known chronic ischemic heart disease, the essential importance of stress imaging is depicted on different levels of decision. Stress imaging methods considered comparable and interchangeable are: stress echocardiography combined with physical or pharmacological stress testing, myocardial perfusion imaging with physical or pharmacological stress testing, dobutamine stress magnetic resonance imaging (DSMR), or myocardial perfusion magnetic resonance tomography (MRT). Basically, no stress imaging method is definitely superior to the others, each method has its own advantages and disadvantages that should be considered and adjusted to the individual patient. Moreover, the NVL KHK gives the recommendation that with the decision for one method also the local availability and institutional expertise of diagnostic centers should be taken into account. However, according to the Bayes theorem, stress imaging combined with physical or pharmacological stress testing is only indicated in patients with an intermediate pretest probability for chronic ischemic heart disease between 10% and 90%. However, the assessment of the pretest probability is difficult or impossible in totally asymptomatic patients with suspected chronic ischemic heart disease. This is exemplified by a typical case report.     

Mechanism of relief of angina after coronary bypass surgery: an angiographic study.

Coronary angiography was performed before and after coronary revascularization in 67 patients. The interval between studies ranged from 1 to 38 months (average 9.9). The patients were separated into four clinical groups on the basis of their symptoms at the time of restudy; Group I, 13 asymptomatic patients; Group II, 19 patients with nonanginal chest pain (18 cases) or dyspnea (1 case); Group III, 12 patients whose angina was relieved but not eliminated; and Group IV, 23 patients whose angina was not alleviated. The graft patency rate was 72 percent in Group I, 78 percent in Group II, 61 percent in Group IIII and 34 percent in Group IV. The sum of diseased, but not bypassed and unsuccessfully bypassed arteries per patient was 1.6 in Groups I and II. 2.9 in Group III and 4.0 in Group IV. The incidence of perioperative myocardial infarction, defined using enzymatic and electrocardiographic criteria, was 8 percent for Group I, 26 percent for Group II, 25 percent for Group III and 52 percent for Group IV. Anginal relief after coronary bypass surgery is achieved by successful and complete revascularization rather than by perioperative myocardial infarction.     

Stage B: What is the Evidence for Treatment of Asymptomatic Left Ventricular Dysfunction?

Although patients with American College of Cardiology / American Heart Association (ACC/AHA) Stage B heart failure, or asymptomatic left ventricular dysfunction (ALVD) are at high risk for developing symptomatic heart failure, few manage-ment strategies have been shown to slow disease state progression or improve long-term morbidity and mortality. Of the pharmacologic therapies utilized in patients with symptomatic disease, only angiotensin converting enzyme (ACE) inhibitors (and to a lesser extent, angiotensin receptor blockers, or ARBs) have been shown to improve clinical outcomes among pa-tients with ALVD. Although evidence to support the use of beta blockers in this setting has been primarily derived from ret-rospective studies or subgroup analyses, they are generally recommended in most patients with ALVD, especially those with ischemic etiology. Statins are associated with improvements in both major adverse cardiovascular events and heart failure events among patients with a history of acute myocardial infarction. Finally, in eligible patients, placement of an automatic implantable cardioverter defibrillator (ICD) has been associated with reduced mortality rates among those with ALVD due to ischemic cardiomyopathy, and some subgroups may derive benefit from cardiac resynchronization therapy or biventricular pacing.     

A Call to Action: Variability in Guidelines for Cardiac Evaluation before Renal Transplantation

Summary

Background and objectives

Candidates for renal transplantation are at increased risk for complications related to cardiovascular disease; however, the optimal strategy to reduce this risk is not clear. The aim of this study was to evaluate the variability among existing guidelines for preoperative cardiac evaluation of renal transplant candidates.

Design, setting, participants, & measurements

A consecutive series of renal transplant candidates (n = 204) were identified, and four prominent preoperative cardiac evaluation guidelines, pertaining to this population, were retrospectively applied to determine the rate at which each guideline recommended cardiac stress testing.

Results

The rate of pretransplant cardiac stress testing would have ranged from 20 to 100% depending on which guideline was applied. The American Heart Association/American College of Cardiology (ACC/AHA) guideline resulted in the lowest rate of testing (20%). In our population, 178 study subjects underwent stress testing: 17 were found to have ischemia and 10 underwent revascularization. The ACC/AHA approach would have decreased the number of noninvasive tests from 178 to 39; it would have identified only 4 of the 10 patients who underwent revascularization. The three other guidelines (renal transplant–specific guidelines) recommended widespread pretransplant cardiac testing and thus identified nearly all patients who had ischemia on stress testing.

Conclusions

The ACC/AHA perioperative guideline may be inadequate for identifying renal transplant candidates with coronary disease; however, renal transplant–specific guidelines may provoke significant overtesting. An intermediate approach based on risk factors specific to the ESRD population may optimize detection of coronary disease and limit testing.     

112例不稳定型心绞痛患者介入治疗的临床评价

目的 探讨不稳定型心绞痛患者介入治疗的安全性及临床效果。方法 不稳定型心绞痛112例．反复发作时即行冠状动脉造影,明确病变后对“罪犯”血管行经皮冠状动脉介入治疗,术后残余狭窄小于10％,前向血流按心肌梗死溶栓治疗临床实验（thrombolysisinmyocardialinfarction,TIMI）血流分级3级为手术成功;随访6月,分析即时及远期效果。结果 手术成功率100％,所有病例均随访6月,其中,17例（15％）患者在经皮冠状动脉介入术后3-6个月再发心绞痛,发作时心电图或平板负荷试验提示心肌缺血,此17例均再次冠状动脉造影提示“罪犯”血管支架内再狭窄,再次行经皮冠状动脉介入术。其余病例术后6个月内未再发心绞痛。随访期间无1例再发心肌梗死或死亡。结论 早期介入治疗不稳定型心绞痛患者是有效的治疗方法,手术成功率及安全性高,近期和远期临床效果满意。     

Role of nitrates in silent myocardial ischemia

Assessment of systemic and coronary hemodynamics, myocardial metabolic and mechanical function and scintigraphic and electrocardiographic studies has provided ample evidence for the existence of asymptomatic silent myocardial ischemia in both acute and chronic coronary artery syndromes. There is growing evidence to suggest that a primary decrease in coronary blood flow, resulting from increased coronary arterial resistance, is the principal cause for spontaneous symptomatic and asymptomatic myocardial ischemia in these patients. The precise mechanism for increased coronary arterial resistance has not been clarified, and it is likely to be different in different angina syndromes but similar for both symptomatic and asymptomatic myocardial ischemia. Since nitroglycerin and nitrates can decrease coronary arterial tone and coronary artery resistance, as well as myocardial oxygen requirements, these agents have the potential to relieve episodes of silent myocardial ischemia in patients with coronary artery syndromes.