You are working with Dr. Lorenzen, who asks you to start interviewing Susan Johnston, a patient she knows well who is here to discuss recent symptoms of chest pain.
You proceed to the patient’s room and review the chart before going into the room.
You learn that Susan Johnston is a 60-year-old female with a history of hypertension and dyslipidemia. On today’s chart the medical assistant has indicated that Ms. Johnson is having episodes of chest discomfort, and has recorded the vitals:
· Temperature is 37 C (98.6 F)
· Pulse is 82 beats/minute
· Respiratory rate is 14 breaths/minute
· Oxygen saturation is 94% on room air
· Blood pressure is 138/78 mmHg
· Weight is 99.8 kg (220 lbs.)
· Height is 167 cm (66 in.)
You enter Ms. Johnston’s room and introduce yourself. Ms. Johnston asks that you call her “Susan.”
With further questioning you discover that at its worst it was a 6 out of 10 in severity. She feels short of breath when the sensation occurs but does not have diaphoresis, nausea, vomiting, dyspepsia or belching, or palpitations. There is no change in the pain with changes in body positioning. The discomfort does not radiate to her neck, jaw, or arm. She has never been awakened from sleep with the sensation. The discomfort is not occurring more frequently and is not changing in its severity.
MEDICATIONS AND HISTORY
Susan tells you she has never had any kind of heart problem, and has never been told she has a heart murmur. She has a history of high blood pressure, and Dr. Lorenzen had also recommended she take a medication for elevated cholesterol but she has not started the cholesterol medication. When you ask why, she states, “I don’t like taking pills.”
· Lisinopril 20 mg daily
· Hydrochlorothiazide 25 mg daily
· She occasionally takes an aspirin but not every day, as it gives her dyspepsia.
Review of Systems:Unremarkable except she has slowly gained weight over the last 15 years.
Social History: Susan has never smoked. She drinks alcohol rarely, does not use recreational drugs, and is monogamous in a married relationship for many years. She has two grown children and works as a secretary. She does not exercise on a regular basis. Dietary history was not detailed but she did admit to eating “quite a bit of fast food.”
Family History: Her father died of a heart attack at age 57. Mother is alive and in relatively good health. One sister has “adult-type diabetes.”
You present the information you have obtained so far to Dr. Lorenzen, then she suggests you both return to the room for Susan’s physical examination.
The findings from the physical examination are:
· Temperature is 37 C (98.6 F)
· Pulse is 82 beats/minute
· Respiratory rate is 14 breaths/minute
· Body mass index is 35.5 kg/m2
· Blood pressure is 136/82 mmHg
· Weight is 99.8 kg (220 lbs.)
· Height is 167 cm. (66 in.)
Head, eyes, ears, nose, and throat (HEENT): No abnormalities.
Neck: No thyromegaly, jugular venous distension or carotid bruits.
Heart: The cardiac point of maximal impulse (PMI) is not palpable. There is no tenderness to palpation of the chest wall. Auscultation reveals a normal rhythm and rate with no murmurs, rubs, or gallops.
Lungs: Symmetric lung excursion. No wheezes or crackles.
Abdomen: Obese, soft and nontender. There is no hepatomegaly or splenomegaly.
Extremities: No clubbing or edema.
Vascular: Pulses in radial, carotid, and dorsalis pedis arteries are brisk, symmetric and 2+ bilaterally.
CHARACTERIZING ANGINAL CHEST PAIN
Dr. Lorenzen asks for your assessment of Susan’s chest pain. You tell her that at this point you feel angina is a possible diagnosis. From your reading on angina, you know that you should try to characterize the patient’s symptoms as typical angina versus atypical angina.
Susan has a burning sensation in her chest associated with dyspnea which occurs with exertion and usually resolves with rest. While the reliable onset with exertion and usual improvement with rest are consistent with typical angina, the burning and tingling quality of her chest pain and lack of radiation are not typical features of angina. You think her symptoms would be considered atypical angina. Dr. Lorenzen agrees with you.
Because Susan’s discomfort has been present for three months, seems to follow a relatively predictable pattern, and has not worsened in severity, frequency, or occurred at rest, her chest pain, if angina, would be characterized as stable angina.
Characterizing Chest Pain and Angina
The three criteria for typical angina
1. Substernal chest discomfort with a characteristic duration and features
2. Provoked by exertion or emotional stress
3. Relief with rest or nitroglycerin
Atypical angina and noncardiac chest pain
Atypical angina is defined as chest pain having two of the three features of typical angina noted above. Occasionally, they will present with only weakness or shortness of breath on exertion. Those symptoms are considered “anginal equivalents.” Noncardiac chest pain is defined as meeting one or none of the characteristic anginal features noted above.
Stable versus unstable angina
Angina occurs when myocardial oxygen demand exceeds supply. When angina is thought to be present it is important to further characterize it as stable angina versus unstable angina since these two syndromes are managed very differently.
· Stable angina pectoris is a predictable pattern of chest discomfort that usually occurs with exertion or extreme emotion. It is relieved by rest or nitroglycerin in less than 5-10 minutes.
· Unstable angina is a more serious condition characterized by chest pain that occurs at rest or with increasingly less exertion. New onset angina (within four to six weeks) and angina that has worsening severity, frequency, or duration is also classified as unstable. Unstable angina is an acute coronary syndrome (along with non-ST segment elevation myocardial infarction and ST segment elevation myocardial infarction) and requires emergency care.
Prevention of Cardiovascular Disease
Primary prevention of cardiovascular disease (preventing disease in those without known disease) involves avoiding tobacco, aggressively controlling diabetes mellitus, keeping blood pressure and cholesterol in the normal range, and regular exercise. The USPSTF recommends initiating low-dose aspirin use for the primary prevention of cardiovascular disease in adults aged 50 to 59 years who have a 10% or greater 10-year CVD risk, are not at increased risk for bleeding, have a life expectancy of at least 10 years, and are willing to take low-dose aspirin daily for at least 10 years. For adults aged 60-69 years of age with a 10% or greater 10 year risk of CVD, the decision to use low-dose aspirin for primary prevention must be individualized based on each patient’s life expectancy and long-term bleeding risk. Recent recommendations from the ACC/AHA Task Force include consideration of low-dose aspirin for primary prevention of ASCVD in adults at increased risk aged 40-70 without risk factors for bleeding. Aspirin use should generally be avoided in individuals over 70, and in those with a history of GI bleeding/peptic ulcer disease, thrombocytopenia, coagulopathy, chronic renal disease, or active use of steroids/nonsteroidal anti-inflammatory drugs/anticoagulants.
Secondary prevention(preventing further disease in those with known disease) involves avoidance of risk factors, more aggressive cholesterol lowering, and optimizing hypertension and diabetic control. Aspirin and statins are mainstays of secondary prevention for most patients. Certain cardiovascular medications such as beta-blockers and angiotensin converting enzyme (ACE) inhibitors may be used as well, particularly for patients who have suffered a myocardial infarction and/or have reduced ventricular systolic function.
You return to the patient’s room.
“Susan, we are concerned about your symptoms. Even though the ECG is normal, we think it’s possible that your chest pain is coming from your heart. We think the blood vessels that go to your heart might be narrowed in spots, resulting in your heart not getting enough blood flow.”
You recommend the following tests and explain the reasoning for each:
· Basic metabolic panel (electrolytes, glucose, renal function)
· Cholesterol panel
Furthermore you recommend the following:
· Susan should begin 81mg of Aspirin daily
· She should watch for any signs of bleeding or GI intolerance on aspirin
· Avoid the activities that cause chest pain for now.
· If the pain is worse than she has experienced or does not resolve quickly she should call emergency medical services.
Susan indicates she understands your instructions, and thanks you for explaining things to her.
CRITERIA FOR METABOLIC SYNDROME
Dr. Lorenzen reviews Susan’s lab results with you and says, “Let’s go over the criteria for the metabolic syndrome. Susan Johnston has at least three of the risk factors—elevated triglycerides, a lower HDL cholesterol level, high blood pressure, and probably an increased waist circumference—and therefore meets the definition of metabolic syndrome.”
Metabolic Syndrome Criteria
The metabolic syndrome is a constellation of risk factors for cardiovascular disease that often occur in the same individual. Together they increase the risk of cardiovascular disease for any given LDL level. Metabolic syndrome has several definitions according to various subspecialty groups; however, all definitions are more alike than they are different. An individual with the metabolic syndrome classically will have central abdominal obesity, impaired glucose tolerance, high blood pressure, and dyslipidemia. The Adult Treatment Panel III of the National Cholesterol Education Program defines the metabolic syndrome as the presence of three or more of the following in an individual:
|Abdominal obesity||Waist circumference (males > 102 cm (40 in), females > 89 cm (35 in)|
|Triglycerides||> 150 mg/dL||1.70 mmol/L|
|HDL cholesterol||males < 40 mg/dL, females < 50 mg/dL||males < 1.04 mmol/L, females < 1.30 mmol/L|
|Blood pressure||> 130/85 mmHg|
|Fasting glucose||> 100 mg/dL||> 6.1 mmol/L|
STRESS TEST INDICATIONS AND OPTIONS
Now that you have additional information on Susan, stable angina continues to be high in the differential diagnosis. Dr. Lorenzen encourages you to consider what you believe Susan’s pretest probability of coronary disease is before thinking about stress testing. She states that thinking about the probability of disease before ordering a test helps guide testing.
After reviewing the guidelines, you believe that based on her atypical presentation and her risk factors, Susan has an intermediate probability of coronary disease—hence, a stress test is a class I indication.
Stress Testing Indications
When Is Stress Testing Indicated?
The American College of Cardiology and American Heart Association’s 1997 Guidelines for Exercise Testing include a table that can be used to assess pre-test probability of coronary artery disease ( Table 2 ) based on age, gender, and symptoms. A more updated version of the guideline, titled Exercise Standards for Testing and Training , provides useful updated information on exercise stress testing procedures and interpretation.
A patient with a high pretest probability should probably go straight to coronary angiogram, because a negative stress test will not convince you the patient doesn’t have a disease. A patient with a low pretest probability should not have a stress test, because it is unlikely to be positive. Therefore, the best patient for a stress test is one with an intermediate pretest probability.
Which Stress Test Should You Order?
Determining which stress test is the best is quite controversial at this time. Options include:
· Treadmill exercise stress testing without additional imaging: Some studies have suggested that females have higher rates of false positives than males, however this diagnostic test can be useful for patients who can exercise to the extent needed. Since the patient can exercise and her baseline ECG is normal, this is a reasonable option.
· Exercise stress testing with nuclear or echocardiographic imaging: Imaging increases the sensitivity and specificity of the test but increases cost too. Nuclear imaging, which utilizes technetium 99m sestamibi or thallium-201, has been reported to result in a high number of false positives in females, possibly due to breast attenuation of smaller heart size. Echocardiography has generally been shown to have the highest diagnostic accuracy for females, but can be technically difficult in the patient with obesity.
· Pharmacologic stress testing with imaging: This is an alternative if the patient cannot exercise to the degree needed to produce a diagnostic result. Options include dipyridamole or adenosine with nuclear imaging or dobutamine with echocardiography.
STRESS TEST RESULTS
You call Susan on the phone and explain the results of her lab testing and chest x-ray to her and inform her that an exercise treadmill stress test is recommended to further investigate her chest discomfort.
The following day, Susan arrives for her stress test. She is attached to the electrocardiogram machine and a resting ECG is obtained. It is not any different from her previous normal ECG. She is given instructions on the treadmill test. Dr. Lorenzen uses the Bruce protocol for the exercise treadmill test.
Exercise treadmill testing
The test is started and Susan exercises until the fifth minute, when she begins to experience the chest discomfort that brought her to the clinic. The electrocardiogram reveals 2 mm downsloping ST segments in leads II, III, aVF, V2, V3, V4 and V5. The test is stopped and over the next four minutes the ST segments return to normal. Her chest pain also resolves with the rest.
This is clearly a positive stress test.
Positive stress test follow-up
Because the treadmill stress test is positive, Susan’s chances of having true angina have increased.
After discussing with the cardiologist on call, it is decided that Susan will be admitted under observation status to the hospital today and undergo the catheterization in the morning. Because the electrocardiogram returned to normal, another reasonable option would be to set the study up in the next week. During the interval, Susan could avoid activities that cause her pain and antianginal medication could be started.
For relief of stable angina symptoms, beta blockers (BBs), calcium channel blockers (CACBs), and nitrates have all been proven to be effective in the treatment of stable angina. These classes of medication may also be useful for secondary prevention of cardiovascular disease through their blood pressure lowering effects in patients with hypertension.
Long-acting formulations of CACBs are recommended for management of stable angina as shorter-acting forms have been associated with greater risk of hypotension and reflex tachycardia, both of which can exacerbate anginal symptoms. At least one study comparing short-acting and long-acting CACB formulations demonstrated a higher mortality risk with a shorter-acting agent. As a result, these short-acting calcium channel blockers are not commonly used today. Longer-acting nitrates are similarly preferred for chronic angina management as they tend to have a lower risk of hypotension, light-headedness, and headache, which promotes better medication adherence.
In their 2012 guidelines, the American College of Cardiology/American Heart Association (ACC/AHA) stated their preference of BBs over CACBs and long acting nitrates since BBs have been shown to improve survival rates in patients with CAD. CACBs and long-acting nitrates should be considered when BBs are contraindicated or as additive therapy when BBs alone are not effective in controlled angina.