CLINICAL CASE PRESENTATION
A 45 year old man with hypertension that has not been well controlled presents for evaluation. He was seen in the office and mentioned 3 separate episodes of non-radiating chest discomfort, lasting 30 minutes, located in the left chest, accompanied by mild dyspnea during the third episode.
His exam revealed blood pressure of 135/88 mm Hg, pulse of 75 beats/min, and a respiratory rate of 16 breaths/min. The jugular venous pressure (JVP) was normal; carotid upstrokes were normal; no bruits were appreciated. The lungs were clear to auscultation and percussion, the abdomen benign, and the extremities free of edema, with normal distal pulses.
An ECG revealed normal sinus rhythm (NSR) and nonspecific ST-T wave abnormalities. He was sent to the chest pain unit in the local emergency department. Serial troponin levels were negative.
DIFFERENTIAL DIAGNOSIS
The differential diagnosis of acute/sub-acute chest pain is extensive and includes life-threatening causes as well as less serious etiologies, such as musculoskeletal pain. Listed below are the acute and potentially life-threatening causes that must be excluded:
• Acute coronary syndrome
• Acute aortic dissection
• Pericarditis with effusion/tamponade
• Pulmonary embolism
• Pneumothorax
• Esophageal perforation
CLINICAL FEATURES
Individuals with chest pain raise clinical concern for the potential of one of a handful of serious, potentially life-threatening etiologies of chest pain.
After clinical, radiographic, and laboratory exclusion of other etiologies, the possibility of unstable angina remains.
• Noninvasive evaluation of those patients with an intermediate probability of ischemic heart disease can be exceptionally useful.
• In patients with positive studies, one’s level of concern for high-grade coronary disease increases and may warrant an invasive evaluation.
• In the situation of a negative study, the probability of an ischemic etiology causing the patient’s symptoms is reduced to a low level, and their prognosis from a cardiac perspective is excellent.
ECHOCARDIOGRAPHIC EVALUATION
Due to his intermediate probability of myocardial ischemia and an ECG with baseline abnormalities that would render a stress ECG indeterminate, he underwent a treadmill stress echo, commensurate with current appropriateness guidelines.1 He exercised 9.5 minutes of the Bruce protocol, stopping due to leg fatigue. He achieved 88% maximum predicted HR. He exhibited no chest pain. The stress ECG demonstrated 1 mm ST depression of indeterminate significance due to the baseline ECG abnormality. The baseline echo demonstrated normal wall motion and ejection fraction (EF). Poststress imaging revealed no wall motion abnormalities and an appropriate increase in EF (Figures 2-1-1 and 2-1-2).
FIGURE 2-1-1 Baseline (left) and poststress (right) of the parasternal images from our patient which demonstrate normal global/regional function at rest and poststress.
FIGURE 2-1-2 Baseline (left) and poststress (right) of the apical images from our patient which demonstrate normal global/regional function at rest and poststress.
DIAGNOSIS
Non-ischemic chest pain
MANAGEMENT
Not only does the negative stress echo study in this situation carry a high negative predictive value, but the study has very favorable prognostic implications. Thus, for most such patients, no further cardiac evaluation is warranted.
• In a study by McCulley, et al, those at intermediate or high pretest probability of coronary disease with a normal test had cardiac event-free survival rates of 99.2%, 97.8%, and 97.4% at 1, 2, and 3 years of follow-up.2
• Furthermore, the exercise time on the treadmill carries additional prognostic significance. Those with a workload of more than 7 METS had event-free survival rates of 99.4% at 1 year and 98.7% at 2 years.
• A meta-analysis published by Metz, et al, found the negative predictive value for MI and cardiac death was 98.8% (95% confidence interval [CI] 98.5 to 99.0) over 36 months of follow-up for myocardial perfusion imaging, and 98.4% (95% CI 97.9 to 98.9) over 33 months for echocardiography.3
• Such patients do, however, warrant appropriate treatment of their modifiable risk factors.
FOLLOW-UP
The patient was advised to maintain follow up of his hypertension and cardiac risk factors for long-term risk reduction of cardiac events and discharged home. Further evaluation of non–life-threatening, noncardiac etiologies of chest pain can be pursued as an outpatient.
REFERENCES
1. Douglas PS, Garcia MJ, Haines DE, et al. ACCF/ASE/AHA/ASNC/HFSA/HRS/SCAI/SCCM/SCCT/SCMR 2011 appropriate use criteria for echocardiography: a report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, American Society of Echocardiography, American Heart Association, American Society of Nuclear Cardiology, Heart Failure Society of America, Heart Rhythm Society, Society for Cardiovascular Angiography and Interventions, Society of Critical Care Medicine, Society of Cardiovascular Computed Tomography, and Society for Cardiovascular Magnetic Resonance. J Am Coll Cardiol. 2011;57(9):1126-1166. doi:10.1016/j.jacc.2010.11.002.
2. McCully RB, Roger VL, Mahoney DW, et al. Outcome after normal exercise echocardiography and predictors of subsequent cardiac events: follow up of 1,325 patients. J Am Coll Cardiol. 1998;31:144-149.
3. Metz, LD, Beattie M, Hom R, et al. The prognostic value of normal exercise myocardial perfusion imaging and exercise echocardiography: a meta-analysis. J Am Coll Cardiol. 2007;49(2):227-237.
SECTION 2
CLINICAL CASE PRESENTATION
The patient is a 51-year-old man with no past cardiac history. He has a past history of Type 2 diabetes and hypertension, both of which have been well managed. He is a manual laborer who presented with complaints of generalized fatigue for a few weeks and exertional dyspnea for 1 week. His exam was benign, and an ECG showed evidence of left ventricular hypertrophy (LVH) with secondary ST-T abnormality. His chest x-ray (CXR) was unremarkable, as was basic laboratory assessment.
DIFFERENTIAL DIAGNOSIS
The differential diagnosis of new onset fatigue and dyspnea is extensive and includes:
• Myocardial ischemia
• LV systolic dysfunction
• Hypertension-induced diastolic dysfunction
• Pericardial effusion with hemodynamic effect
• Pulmonary hypertension
• Pulmonary embolism
• Parenchymal lung disease
ECHOCARDIOGRAPHIC EVALUATION
His symptoms of exertional dyspnea and fatigue raised an intermediate probability of an ischemic etiology.
• Due to his intermediate probability of an ischemic etiology for his symptoms, a treadmill stress echo was ordered.
• With the resting ECG displaying LVH with secondary ST-T abnormality, pursuing stress testing with echo imaging was appropriate, as the baseline ECG abnormalities decrease the predictive value of postexercise ST changes.
Stress Test Results
• His resting echo images were normal. He exercised 7 minutes on the Bruce protocol, stopping due to chest discomfort (angina) and dyspnea.
• He exhibited nearly 1 mm ST depression from baseline.
• The postexercise images revealed LV dilation, with severe hypokinesis or akinesis of the anterior, lateral, and apical segments. The left ventricular ejection fraction (LVEF) dropped from 55% to 35% (Figures 2-2-1 and 2-2-2)
FIGURE 2-2-1 Baseline (left) and poststress (right) of the parasternal images from our patient, which demonstrate normal global/regional function at rest with multiple new wall motion abnormalities as described in the text poststress. Note also the LV cavity dilation.
FIGURE 2-2-2 Baseline (left) and poststress (right) of the apical images from our patient which demonstrate normal global/regional function at rest with multiple new wall motion abnormalities as described in the text poststress.
Stress Echo Evaluation and Interpretation
• The echocardiographic criteria for the detection of myocardial ischemia is the development of new or worsening regional contractile function (regional wall motion abnormality) during stress.
• A region of myocardium that exhibits normal contractile function at baseline that becomes hypokinetic or akinetic poststress, or a region of myocardium that is hypokinetic at baseline that becomes akinetic poststress, constitutes an abnormal response.
• The worse the LVEF and the greater the number of LV segments that are abnormal poststress, the worse the prognosis.2
• Our patient’s study displayed several high-risk features, including LV dilation, multiple wall motion abnormalities, and a significant drop in LVEF postexercise. This group of individuals with these high-risk features derives the greatest benefit from further evaluation with coronary angiography and revascularization.
DIAGNOSIS
Myocardial ischemia with high-risk features
MANAGEMENT
• Due to the abnormal stress echo with high-risk features, cardiac catheterization with coronary angiography was recommended.
• This study demonstrated a chronic total occlusion of the left anterior descending (LAD) artery with the distal vessel filling via collaterals, and a 90% stenosis of the obtuse marginal (Figure 2-2-3).
• Surgical revascularization was performed, and he had an unremarkable postoperative course and recovery.
FIGURE 2-2-3 Representative still images from the patient’s coronary angiogram. The panel on the left demonstrates the left coronary artery anatomy. The LAD is not seen as it is totally occluded. The right coronary angiogram seen on the right panel demonstrates collateral flow from the RCA to the LAD.
FOLLOW-UP
Post revascularization (surgical or percutaneous) management should include pharmacologic therapy and treatment of modifiable risk factors:
• This patient’s pharmacologic therapy consisted of aspirin, a thienopyridine, β-blocker, statin agent, and an ACE inhibitor.
• He was referred to cardiac rehabilitation for a graded exercise program and dietary education, with periodic lipid assessment to ensure he achieves and maintains NCEP ATP III goals.
REFERENCES
1. Douglas PS, Garcia MJ, Haines DE, et al. ACCF/ASE/AHA/ASNC/HFSA/HRS/SCAI/SCCM/SCCT/SCMR 2011 appropriate use criteria for echocardiography: a report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, American Society of Echocardiography, American Heart Association, American Society of Nuclear Cardiology, Heart Failure Society of America, Heart Rhythm Society, Society for Cardiovascular Angiography and Interventions, Society of Critical Care Medicine, Society of Cardiovascular Computed Tomography, and Society for Cardiovascular Magnetic Resonance. J Am Coll Cardiol. 2011;57(9):1126-1166. doi: 10.1016/j.jacc.2010.11.002.
2. Yao S, Qureshi E, Sherrid M, Chaudhry F. Practical applications in stress echocardiography: risk stratification and prognosis in patients with known or suspected ischemic heart disease. J Am Coll Cardiol. 2003;42(6):1084-1090.
CLINICAL CASE PRESENTATION
A 41-year-old woman with systemic lupus erythematosus (SLE), hypertension, and CAD status postpercutaneous revascularization of the LAD and right coronary artery (RCA), identified when she presented with unstable angina 2 years ago, presents with increasing frequency of chest pain. Over the past year, she has noted episodes of substernal, nonradiating chest discomfort without associated symptoms, lasting no more than 5 minutes in duration. The discomfort has been occurring more frequently in the past couple of weeks. She also notes episodes of exertional dyspnea in addition to brief spells of lightheadedness and fatigue. Her past history is otherwise notable for chronic back pain for which she takes narcotic therapy.
She is afebrile, her blood pressure is 109/69 mm Hg, her pulse is 63 beats/min, and her respiratory rate is 12 breaths/min. The JVP is normal; no carotid bruits are appreciated. The lungs were clear to auscultation and percussion. The PMI was non-displaced. S1 and S2 were normal; no murmurs, gallops, or rubs were evident. Her abdomen was benign, and the extremities were free of edema with normal distal pulses.
An ECG revealed sinus bradycardia and was normal.
DIFFERENTIAL DIAGNOSIS
The differential diagnosis of chest pain in this patient is extensive.
• One must first exclude recurrent myocardial ischemia in this patient with known CAD.
• If recurrent myocardial ischemia is excluded, pursuit of other nonischemic cardiac causes (such as pericardial involvement from her SLE) or other noncardiac causes would be appropriate.
ECHOCARDIOGRAPHIC EVALUATION
• Her clinical situation does not raise concern for other serious etiologies of chest pain, and her clinical probability of the symptoms being due to myocardial ischemia is intermediate.
• Her ECG did not suggest a pericardial process (see Chapter 6).
• A stress test with imaging is a reasonable first step in her evaluation.
• As she cannot walk any significant distance due to her chronic back pain, she underwent a dobutamine stress echo.
Pharmacologicess testing is an accepted alternative to physical stress testing in individuals who are unable to exercise.
• Dobutamine was infused intravenously in a graded fashion to a peak dose of 40 mcg/kg/min.
She had no symptoms, but exhibited 1.5 mm ST depression on ECG and displayed multiple wall motion abnormalities at peak infusion, involving the inferior, inferolateral, apex, and septal walls.
Her LVEF dropped from 55% at baseline to 35% at peak infusion. Figures 2-3-1 to 2-3-4 demonstrate each view at baseline, low dose, intermediate dose, and peak dobutamine infusion in a quad screen format, which facilitates interpretation. This study reflected adverse prognostic features, as discussed in the previous case.1,2
FIGURE 2-3-1 Parasternal long axis view at baseline (upper left), low dose (upper right), intermediate dose (lower left), and peak dobutamine infusion (lower right). The accompanying videos demonstrate normal wall motion at rest with new wall motion abnormalities at peak infusion as described in the text.
FIGURE 2-3-2 Parasternal short axis at baseline (upper left), low dose (upper right), intermediate dose (lower left), and peak dobutamine infusion (lower right). The accompanying videos demonstrate normal wall motion at rest with new wall motion abnormalities at peak infusion as described in the text.
FIGURE 2-3-3 Apical 4 chamber view at baseline (upper left), low dose (upper right), intermediate dose (lower left), and peak dobutamine infusion (lower right), The accompanying videos demonstrate normal wall motion at rest with new wall motion abnormalities at peak infusion as described in the text.
FIGURE 2-3-4 Apical 2 chamber view at baseline (upper left), low dose (upper right), intermediate dose (lower left), and peak dobutamine infusion (lower right). The accompanying videos demonstrate normal wall motion at rest with new wall motion abnormalities at peak infusion as described in the text.
DIAGNOSIS
Myocardial ischemia with high-risk stress echo features
MANAGEMENT
Due to the marked abnormalities noted on this study, cardiac catheterization with coronary angiography was recommended and performed.
• The LAD stent was patent with no significant lesions throughout the course of the vessel.
• The proximal RCA stents were patent, but distal to the stents a 95% lesion was identified. A new drug-eluting stent was placed (Figure 2-3-5).
• Her hospital course was unremarkable, and she has remained free of chest pain in the early post discharge period.
FIGURE 2-3-5 RCA angiogram from this patient. The proximal RCA stents were patent, but distal to the stents, a 95% lesion is seen.
FOLLOW-UP
Post revascularization management should include pharmacologic therapy and treatment of modifiable risk factors:
• Her pharmacologic therapy at the time of discharge consisted of aspirin, a thienopyridine, β-blocker, statin agent, and an ACE inhibitor.
• She was referred to cardiac rehabilitation for a graded exercise program and dietary education, with periodic lipid assessment to ensure she achieves and maintains NCEP ATP III goals.
REFERENCES
1. Yao S, Qureshi E, Sherrid M, Chaudhry F. Practical applications in stress echocardiography: risk stratification and prognosis in patients with known or suspected ischemic heart disease. J Am Coll Cardiol. 2003;42(6):1084-1090.
2. Marwick TH, Case C, Sawada S, et al. Prediction of mortality using dobutamine echocardiography. J Am Coll Cardiol. 2001;37:754-760.
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