MEDICAL FOLLOW-UP AND SECONDARY PREVENTION
VA/DoD CLINICAL PRACTICE GUIDELINE FOR THE
MANAGEMENT OF ISCHEMIC HEART DISEASE
GUIDELINE SUMMARY MODULE G
MEDICAL FOLLOW-UP AND SECONDARY PREVENTION
|
Patients who have a history of ischemic heart disease (IHD) are candidates for secondary prevention of further coronary events. These include patients with prior myocardial infarction (MI), ischemic cardiomyopathy, silent ischemia, segmental wall motion abnormality by left ventricular (LV) angiography or cardiac ultrasound, positive stress test, prior coronary revascularization, pathologic Q-waves on the resting electrocardiogram (ECG), and males greater than age 50 with typical angina. This guideline emphasizes the assessment of clinical predictors for progression of IHD and identifies areas for which there are effective interventions. It also emphasizes that all patients are on optimal doses of pharmacological therapies with proven morbidity and mortality benefits, and that patients are assessed for possible benefits from a revascularization procedure. This guideline also emphasizes the assessment for coronary artery disease risk factors, where interventions are known to reduce the likelihood of future coronary events (particularly smoking, diabetes, dyslipidemia, and hypertension). Although the evidence of benefit is less strong, the diagnosis and treatment of depression and promotion of cardiac rehabilitation are also discussed. |
§ Identify and triage IHD patients with a possible acute coronary syndrome (i.e., ST-elevation myocardial infarction (STEMI), non-ST-elevation myocardial infarction (NSTEMI), or unstable angina).
§ Assess if stable symptoms are due to non-cardiac conditions.
§ Identify and treat other medial conditions that may exacerbate IHD symptoms.
§ Ensure all patients receive aspirin (or other antiplatelet therapy, as appropriate).
§
Titrate pharmacological
therapy for ischemia, angina, and CHF to physiologic end-points, therapeutic
doses or patient tolerance.
§ Administer a cardiac stress test to assess the risk of future cardiac events, if not previously performed or if there has been worsening of ischemic symptoms.
§ Initiate ACE inhibitor therapy for patients with significant diabetes and/or left ventricular dysfunction (EF <0.40). Consider in patients without LV dysfuntion.
§ Identify and provide therapy for patients with heart failure.
§ Identify patients at high-risk for sudden cardiac death or complications for whom a cardiology referral is appropriate.
§ Assure appropriate treatment with beta-blockers in patients with prior MI.
§ Identify and treat patients with high LDL-C.
§ Assess and treat high blood pressure.
§ Reduce cardiac risk with smoking cessation.
§ Promote cardiac rehabilitation as secondary prevention.
§ Achieve tight glycemic control in diabetics.
§ Screen for depression and initiate therapy or refer.
§ Arrange follow-up.
MEDICAL FOLLOW-UP AND SECONDARY PREVENTION
Candidates for secondary prevention of ischemic heart disease (IHD) are patients who have a history of clinical coronary disease.
Accepted criteria for a diagnosis of coronary artery disease (CAD) include the following:
§ Prior myocardial infarction (MI) and/or pathologic Q-waves on the resting electrocardiogram (ECG)
§ Typical stable angina in males > age 50
§ Cardiac stress test showing evidence of myocardial ischemia
§ Left ventricular (LV) segmental wall motion abnormality by angiography or cardiac ultrasound
§ Silent ischemia, defined as reversible ST-segment depression by ambulatory ECG monitoring
§ Significant obstructive CAD by angiography
§ Prior coronary revascularization (percutaneous coronary intervention or coronary artery bypass graft surgery)
Stable patients with IHD may experience sudden or acute changes
in their clinical status (i.e., ST-elevation myocardial infarction (STEMI), non-ST-elevation myocardial infarction
(NSTEMI), or unstable angina). The diagnosis of acute coronary
syndrome (ACS) may be suspected on the basis of a
compelling clinical history, specific ECG findings, and/or elevations in serum
markers of cardiac necrosis. The following presents a logical means by which
the primary care provider may decide if the patient has an acute coronary
syndrome (ACS).,
and therefore, be referred
to specific management for Acute Coronary Syndrome.
The following may be symptoms of myocardial ischemia. If they are new or are occurring in an accelerating fashion, they should prompt consideration of a possible ACS.
§
New onset or worsening chest pain, discomfort,
pressure, tightness, or heaviness
—“New onset” is defined as chest pain or discomfort being evaluated for the first time or the patient with a complaint of chest pain is new to the clinic.
—“Worsening” is defined as at least a one-class
increase (Canadian Cardiovascular Society angina classification) in a patient
with known previous symptoms attributed to MI.
§
Chest pain, discomfort, pressure, tightness, or
heaviness (at least a one-class increase in the Canadian Cardiovascular
Society (CCS) classification
§ Radiating pain to the neck, jaw, arms, shoulders, or upper back
§ Unexplained or persistent shortness of breath
§ Unexplained epigastric pain
§ Unexplained indigestion, nausea, or vomiting
§ Unexplained diaphoresis
§
Unexplained weakness, dizziness, or loss of
consciousness
Patients
with evidence of acute (within 2 weeks) or subacute (>2 weeks) changes in symptoms should be evaluated using the
core module.
§ Pleuritic pain (i.e., sharp or knife-like pain brought on by respiratory movements or cough).
§ Primary or sole location of discomfort in the middle or lower abdominal regions.
§ Pain that may be localized at the tip of one finger, particularly over costochondral junctions or the LV apex.
§ Pain reproduced with movement or palpation of the chest wall or arms.
§ Constant pain that lasts for many hours.
§ Very brief episodes of pain that last a few seconds or less.
§ Pain that radiates into the lower extremities.
Provide the
patient with optimal control of his or her symptoms of myocardial ischemia.
The level of symptoms that constitute “adequate control” is highly dependent on
the following:
§
Stage
of the CAD.
§
Whether
or not revascularization is feasible at an acceptable risk.
§
Patient’s
tolerance or intolerance of anti-anginal drugs.
§
Patient’s
preference.
Changes in exercise tolerance and
symptoms, over time, are particularly useful in assessing the adequacy of
control of myocardial ischemia symptoms. The Canadian Cardiovascular Society
(CCS) classification of angina (1994) is useful for the serial assessment of
exercise tolerance and anginal symptoms.
Patients with inadequate control of their symptoms should be evaluated using
the core module.
|
Class I |
Angina only with strenuous exertion |
|
Class II |
Angina with moderate exertion |
|
Class III |
Angina with minimal exertion or ordinary activity |
|
Class IV |
Angina at rest or with any physical activity |
A focused history should include assessment of risk factors for which interventions can improve outcome. Life-extending therapies, such as beta-blockers after MI, aspirin (ASA), angiotensin-converting enzyme (ACE) inhibitors
and lipid-lowering therapy, are under-prescribed in patients with known IHD
Ensure that all patients with LV dysfunction are on optimal doses of pharmacological therapies with proven morbidity and mortality benefits.
Randomized trial evidence has shown a survival benefit for patients with severe congestive heart failure (CHF) and/or severe systolic dysfunction (LVEF <0.35 to 0.40) treated with ACE inhibitors, beta-blockers, or spironolactone. No mortality benefit has been found with the use of digoxin in patients with CHF from LV systolic dysfunction. Both ACE inhibitors and beta-blockers have been proven to be beneficial in patients with both mild and more severe CHF. Spironolactone, on the other hand, has only been studied in patients with severe heart failure already on an ACE inhibitor. Because of the more extensive data supporting the use of both ACE inhibitors and beta-blockers, these agents should be initiated prior to initiation of spironolactone.
ACE inhibitors
should be given to all patients with IHD,
in the absence of recognized contraindications (e.g., angioedema), with
diabetes mellitus and/or with
CHF or evidence for LV systolic dysfunction (EF <0.40), and all
attempts should be made to have patients on at least 20 mg of enalapril, or its
equivalent, a day. ACE inhibitors should also be considered in
patients with IHD or other vascular disease even in the absence
of diabetes or LV systolic dysfunction. Angiotensin II receptor
blockers should be substituted when there is a contraindication to the use of
ACE inhibitors.
Beta-blockers have been shown to improve survival
following myocardial infarction. In the absence of contraindications,
beta-blockers are recommended in all patients with stable
angina with or without prior history of
myocardial infarction. Asymptomatic
patients with documented IHD but without prior history of myocardial infarction
should also be considered for treatment with beta-blockers.
In patients with moderate to severe CHF symptoms, beta-blockers have been shown to improve symptoms, New York Heart Association (NYHA) class, and overall morbidity and mortality. Thus far, studies support use of carvedilol, metoprolol, and bisoprolol for this indication. Before using beta-blockers, all patients should be on optimal doses of an ACE inhibitor, as in the clinical trials. Beta-blockers should not be used in uncompensated CHF and should be used with great caution in patients with Class IV CHF.
A randomized trial using a relatively low dose of spironolactone demonstrated significant improvement in outcomes in patients with severe CHF (i.e., Functional Class 3 to 4) who were already on ACE inhibitor therapy. Remarkably, in this trial, the incidence of hyperkalemia was not increased with this dose of spironolactone. The effect of spironolactone in patients with less severe CHF is unknown.
The DIG Study
(1997) showed no benefit in terms of mortality, but some reduction in frequency
of hospitalization with the use of digoxin in patients with CHF. Discontinuing
digoxin in patients with compensation compensated heart
failure often results in worsening of symptoms.
While there is no evidence supporting mortality benefit of
diuretics in patients with heart failure, diuretics are useful in the
management of symptomatic volume overload.
Medical Therapies
|
Recommended Medications |
|
Aspirin reduces cardiovascular (CV) events in patients with acute MI, previous MI, and unstable angina. |
|
Aspirin reduces risk of MI in patients with chronic stable angina. |
|
Beta-blockers improve symptoms in patients with IHD. |
|
Beta-blockers improve morbidity and mortality in patients with IHD and previous MI. |
|
Beta-blockers reduce CV events in patients with silent ischemia. |
|
ACE inhibitors for patients with IHD and low ejection fraction (EF) improve morbidity and mortality. |
|
Lipid-lowering therapy improves CV outcomes in patients with IHD and elevated lipids. |
|
Lipid-lowering therapy improves CV outcomes in patients with IHD and average cholesterol. |
|
Gemfibrozil improves outcomes in patients with IHD and low high-density lipoproteins – cholesterol (HDL-C). |
Medical Therapies for IHD Patients with LV Dysfunction
Recommended Medications |
|
ACE inhibitors improve morbidity and mortality in patients with CHF or low EF. |
|
Asymptomatic patients, but with low EF, experience survival benefit from ACE inhibitors. |
|
Doses of ACE inhibitors should be equivalent 20 mg enalapril qd to obtain greatest benefit. |
|
Beta-blockers should be considered for all patients with NYHA class II or III CHF, and EF<0.40, after stabilization on ACE inhibitors. |
|
Addition of spironolactone to ACE inhibitors and diuretics in patients with severe heart failure improves morbidity and mortality. |
|
Digoxin use in heart failure (EF<0.45) does not affect mortality, but decreases hospitalization due to heart failure. |
|
Diuretics improve symptoms of volume overload. |
Ensure the patient is on optimal anti-anginal therapies.
§ Beta-adrenergic blocking agents are generally considered the first drug of choice because there is:
—Documented survival benefit in patients with prior MI, and
—Reduced morbidity from stroke and heart failure and a survival benefit in patients with hypertension
A commonly used “rule of thumb” is to
titrate the beta-blocker to angina relief or to a resting heart rate of 55 to
60..
In some patients with severe angina that is refractory to therapy, a lower
heart rate could be maintained provided that the patient does not have symptoms
due to bradycardia.
§
Calcium channel-blocking agents are equally effective
as beta-adrenergic blocking agents in providing angina relief and in enhancing
exercise duration to 1 mm ST-segment depression. tolerance
and can be considered as an effective alternative to beta-blockers in patients
unable to tolerate beta-blockers or as initial therapy
in place of beta-blockers. Therefore,
in patients without prior MI or hypertension, a long-acting calcium channel
agent would be acceptable.
§ Long-acting nitrate may be used in beta blockers are contraindicated or patient is unable to tolerate beta-blockers
§ Sublingual nitroglycerin is still the mainstay therapy for the immediate relief of angina that has been provoked by exertion or emotion.
—Sublingual nitroglycerin, when taken prior to an activity that commonly causes angina (e.g., walking up stairs or up hill), will often prevent the development of symptoms. Several forms of longer acting nitrates (e.g., isosorbide dinitrate and isosorbide mononitrate, and topical nitroglycerin patches) are also commonly used for prophylaxis of angina.
—Care must be taken to ensure a nitrate-free interval of 8 to 12 hours out of every 24 to prevent the development of tolerance.
—The use a nitrate preparation within 24 hours of the use of sildenafil (Viagra) may cause dangerous hypotension.
The following eponym may aid in remembering treatment elements that should be considered:
A = Aspirin and anti-anginal therapy
B = Beta-blocker and blood pressure
C = Cigarette smoking and cholesterol
D = Diet and diabetes
E = Education and exercise
Among
patients with known IHD, the risk of future fatal and non-fatal coronary events
ranges from no detectable increase compared to individuals without known IHD to
>50 percent per year. Knowledge of such risk is essential to planning
diagnostic and treatment strategies. The incidence of complications from
non-invasive risk stratification in appropriately selected candidates is
extremely low. Thus, the main arguments for not performing non-invasive risk
stratification include the following:
§
Major
morbidity limiting functional status (e.g., bed-ridden from multiple strokes)
§
Major
morbidity limiting life expectancy (e.g., metastatic cancer)
§
Patient
refusal
Non-invasive
risk assessment has two components: (1)
assessment of left ventricular function. , and (2) cardiac stress
testing to identify patients likely to have ischemic myocardium at risk.
Left ventricular systolic dysfunction is one of the strongest predictors of both increased mortality and increased morbidity, including CHF and malignant arrhythmias. Pharmacologic therapy and/or revascularization can favorably affect this clinical course.
Accepted criteria for at least one assessment of LVF in patients with known CAD, include the following:
§
Symptoms of CHF (e.g., orthopnea or
paroxysmal nocturnal dyspnea)
§ Significant impairment or recent decrement in exercise tolerance, due to dyspnea or fatigue
§ Physical signs of CHF (e.g., elevated jugular venous pressure, unexplained pulmonary rales, laterally displaced point of maximal impulse, and S3 gallop)
§ Cardiomegaly on chest x-ray
§ History of prior MI or pathologic Q-waves on the ECG
Repeat assessment is indicated if there has been an unexplained worsening of CHF symptoms or signs or a significant decrement in exercise tolerance, due to fatigue or dyspnea. Routine reassessment of LVF in stable patients is not indicated.
It is also important to recognize that patients with normal
or near-normal LVF (EF >0.40) may experience symptoms of heart failure due
to diastolic LV dysfunction. Such patients may also experience symptomatic
benefit from diuretics and nitrates, but there is little or no evidence of
benefit from calcium channel blockers or ACE inhibitors. For specific
recommendations for the treatment of diastolic heart failure, the provider is referred
to the ACC/AHA Task Force on Practice Guidelines, Guidelines for the evaluation
and management of heart failure (19952001?).
Select the most appropriate method for the
assessment of LV systolic function. LV systolic function may be
assessed by contrast angiography at cardiac catheterization, two dimensional cardiac
ultrasoundechocardiogram, and radionuclide
ventriculography. An echocardiogram is
preferable in evaluation of patients who also have a systolic murmur suggestive
of mitral regurgiatation in order to assess the severity of mitral
regurgitation along with assessment of LV systolic function.
Of note, Silver et al, (1994) developed a clinical rule to identify patients with prior MI who had LVEF >0.40. He found a positive predictive value of 98 percent in those patients who have ALL of the following characteristics:
§ An interpretable ECG (no left bundle branch block (LBBB), ventricular pacing, or LVH with strain pattern)
§ No prior Q-wave MI
§ No history of CHF
§ Index MI which is not a Q-wave anterior infarction
Cardiac stress testing is indicated in the initial evaluation of
all patients with known IHD (with the exceptions noted above), unless there are
criteria for proceeding directly to cardiac catheterization and coronary
arteriography (see Referral to Cardiology below). Patients undergoing
only a submaximal exercise stress test (EST) prior to discharge for an acute
myocardial infarction (AMI) should receive a symptom-limited EST at 3 to 6 weeks
from discharge. Patients with evidence for inducible ischemia during risk
stratification should be considered for further cardiac evaluation, such as
coronary arteriography. Repeat cardiac stress testing is indicated if there has
been a significant change in symptoms or decrement in exercise tolerance;
however, routine periodic stress testing is not indicated.
With only a few
exceptions, coronary angiography is generally not indicated in asymptomatic or
mildly symptomatic patients with either known or suspected CAD, unless
non-invasive testing reveals findings that suggest a high risk for adverse
outcomes. Also, some patients with extenuating circumstances should not be routinely referred to cardiology.
These general circumstances include the following:
§ Review of prior coronary angiogram by current clinician shows disease not amenable to revascularization by current standards.
§
Patient refusal of
catheterization and/or revascularization and/or patient and physician prefer medical
therapy alone, without further evaluation.
§
Non-cardiac disease with
projected life expectancy <6 months or quality of life unlikely to be
improved by revascularization.
The following indications for referral to a cardiologist apply only to patients with stable IHD, and not to those with a current or recent ACS, in whom different criteria apply.
§
Patients with Canadian Class
3-4 symptoms of ischemia or heart failure on medical therapy.
§
Patients dissatisfied with
symptoms despite maximal medical therapy.
§
Patients with recurrent
symptoms following recent (<6 mo) revascularization.
§
Patients at Increased Risk for Sudden Cardiac Death
§
Patients with High-Risk Findings on Non-Invasive
Testing
§
Patients with non-invasive
test results that are inadequate for management.
Patients with increased risk for sudden
cardiac death would benefit either from an electrophysiologic (EP) study and/or
EP therapyfrom evaluation by an electrophysiologist for consideration
of an implantable cardiovertor defibrillator device, include:
—History
of sudden cardiac death
—History of sustained monomorphic ventricular tachycardia
—Reduced LVF
(EF<0.40) and nonsustained ventricular tachycardia
—Reduced LVF
(EF<0.40) and syncope of undetermined etiology
---Reduced
LVF (EF <0.30) and prior history of MI
—Severe resting
left ventricular dysfunction (LVEF<35%)
—High-risk Duke
treadmill score (score < -11)
—Severe exercise left
ventricular dysfunction (exercise LVEF<35%)
—Stress-induced
large perfusion defect (particularly if
anterior)
—Stress-induced
moderate-size multiple perfusion defects
—Large, fixed
perfusion defect with left ventricular dilatation or increased lung uptake (201Tl)
—Stress-induced
moderate-size perfusion defect with left-ventricular dilatation or increased
lung uptake (201Tl)
—Echocardiographic
wall motion abnormality (involving >2 segments) developing at low dose of
dobutamine (10 mcg, · kg-1,
· min-1)
or at a low heart rate (<120 bpm)
—Stress
echocardiographic evidence of extensive ischemia
Consideration
for bypass surgery:
Patients with results from coronary angiography that suggest the need for coronary bypass surgery, but which have not been addressed to the satisfaction of the patient or provider. Patients with the following coronary anatomic findings warrant consideration for bypass surgery:
—Significant left main coronary artery stenosis
—Left main equivalent: significant (70 percent) stenosis of
proximal LAD and proximal left circumflex artery
—Three-vessel disease (Survival benefit is greater in
patients with abnormal LV function; e.g., with an EF <0.50.)
—Proximal LAD stenosis with 1- or 2-vessel disease