CME Geriatrics The Heart Series editors: Bernard L. Segal, MD, Marc A. Tecce, MD, and Fredrick T. Sherman, MD, MSc Echocardiography The role of this noninvasive test in the geriatric population Barbara A. Berko, MD Alyson N. Owen, MD Donna R. Zwas, MD Echocardiography assumes a major role in the diagnosis and evaluation of cardiovascular disease in the older population. Available diagnostic modalities are briefly reviewed and their role in identifying disease entities common in a geriatric population is discussed. The prognostic implications of echocardiographic findings of mitral annular calcification and aortic sclerosis are reviewed, as are the use of echo and Doppler techniques in the assessment of congestive heart failure. Particular emphasis is placed on the evaluation of ischemic heart disease using stress echocardiography, the diagnosis and assessment of degenerative aortic valve disease, and the role of transesophageal echo in the management of atrial fibrillation and stroke. Berko BA, Owen AN, Zwas DR. Echocardiography: The role of this noninvasive test in the geriatric population. Geriatrics 2003; 58(July):30-34. Key words: echocardiography Doppler treadmill dobutamine Echocardiography is the mainstay of noninvasive cardiovascular diagnosis. It is often the first test, after ECG, performed when cardiac pathology is suspected. Due to its noninvasive and portable nature, echocardiography can be performed rapidly in a variety of settings and repeated as often as necessary. It provides vast quantities of information about anatomy and physiology. Echocardiography has particular relevance in the older population because the majority of patients with cardiovascular disease are over age 65. Echocardiographic techniques Transthoracic echocardiography (TTE) is the foundation of echocardiographic diagnosis, and is performed by applying sonographic transducers to the chest wall in specific locations to obtain a series of standardized views. TTE can also Dr. Berko is clinical assistant professor of medicine, Jefferson Medical College, Thomas Jefferson University, and Jefferson Heart Institute, Philadelphia, PA. Dr. Owen is assistant professor of medicine, Jefferson Medical College, Thomas Jefferson University, and Jefferson Heart Institute, Philadelphia, PA. Dr. Zwas is clinical assistant professor of medicine, Jefferson Medical College, Thomas Jefferson University, and Jefferson Heart Institute, Philadelphia, PA. Disclosure: The authors have no real or apparent conflicts of interest relating to the content presented here. be performed after exercise or pharmacologic stress. Transthoracic echocardiography is limited by the need to penetrate the chest wall in between the ribs in order to obtain images of the heart and by interference from air in the lungs. Transesophageal echocardiography (TEE), performed by placing a modified endoscope with a rotating ultrasound transducer at its tip into the esophagus, has the advantage of giving the transducer closer apposition to the heart without interference from air in the lungs. It has the disadvantage, however, of being semi-invasive, and requires the use of sedation. Spectral Doppler imaging permits the quantitative measurement of flow velocities, which can be converted to pressure gradients using the Bernoulli equation from fluid dynamics, allowing the assessment of stenotic valves. Color flow Doppler imaging permits the qualitative detection and spatial localization of turbulent flow, helping to quantify valve regurgitation and shunts. Ischemic heart disease The assessment of overall systolic function is critical to the clinical management of the patient with coronary artery disease (CAD) as it provides prognostic information and helps guide medical therapy. Experienced echocardiographers can qualitatively estimate left ventricu- 30 Geriatrics July 2003 Volume 58, Number 7
lar (LV) ejection fraction with reasonable accuracy when images provide good endocardial border definition. The ability to image in multiple planes permits the echocardiographic assessment of regional wall motion. The presence of regional wall motion abnormalities establishes the diagnosis of underlying coronary artery disease, and the location of the wall motion abnormality has correlated well with the location of coronary stenoses at cardiac catheterization. In the acute evaluation of chest pain (eg, in the emergency department or CCU), the absence of a segmental wall motion abnormality during pain makes coronary disease unlikely and suggests a good prognosis. 1 Technologic advances have made stress echocardiography a valuable tool in the diagnosis and assessment of ischemia. Echo images in multiple planes are obtained at rest and immediately following exercise or pharmacologic stress in conjunction with ECG monitoring. Overall LV function and regional wall motion can be directly compared at rest and under stress to identify myocardial segments that develop reduced contraction with stress, identifying ischemia. Correlations with nuclear stress testing techniques and cardiac catheterization have been excellent. The sensitivity of stress echo for the detection of multivessel coronary disease, which is common in older patients, is greater than 90%. 2 In an older population, treadmill exercise is often limited by arthritis, peripheral vascular disease, or poor exercise tolerance. Pharmacologic stress using dobutamine infusion with echo yields similar diagnostic sensitivity and specificity to treadmill stress testing. 3 Older patients often must undergo major non-cardiac surgery and dobutamine stress echo has proven helpful in preoperative assessment. A normal stress echo has a high negative predictive value, identifying a negligible risk of perioperative cardiac events. 4 www.geri.com Congestive heart failure Congestive heart failure (CHF) is a common clinical problem in the older patient, as the prevalence of heart failure approaches 10% in individuals over age 80. 5 Determining whether heart failure results from systolic dysfunction, diastolic dysfunction, or significant valvular disease is critical to further evaluation and treatment. Systolic function is typically evaluated qualitatively (eg, normal, or mildly, moderately, or severely depressed or by visually estimating ejection fraction), although actual quantitative methods of calculating ejection fraction exist and are reasonably accurate. If systolic dysfunction exists, a large body of literature and many guidelines address appropriate therapy, including use of angiotensin-converting enzyme inhibitors and beta blockers. As many as 40 to 50% of patients with clinical CHF have normal LV systolic function, and this may be even more common in an older population. Doppler echocardiography has been used extensively to evaluate diastolic function. In normal young and middleaged individuals, early rapid filling (E) dominates the mitral inflow pattern, and the atrial component (A) is smaller, resulting in an E/A ratio >1. Progressive abnormalities of diastolic dysfunction have been determined with first E/A reversal, with a decrease in E wave velocity and an increase in A wave velocity such that E/A ratio is <1, then pseudonormalization, and finally an increase in the E/A ratio to greater than 2:1, indicating restrictive physiology. This seemingly simple ratio can be difficult to interpret and is influenced by multiple factors, including preload, atrial contractility, and ventricular systolic function; therefore, the diagnosis of congestive heart failure is clinical rather than echocardiographic. In the geriatric population, the analysis of diastolic function becomes even more complex due to the normal effects of aging on cardiac function. Doppler studies have demonstrated a decrease in E/A ratio as age increases, such that the majority of individuals over age 65 have E/A reversal implying impaired LV relaxation. 5 The majority of these patients, however, do not have clinical heart failure. Marked E/A reversal may be taken as evidence of impaired filling beyond that which is usually associated with age alone. A restrictive filling pattern in the presence of decreased systolic LV function is associated with a significantly elevated filling pressure and conveys a poor prognosis in patients with CHF. 6 Aortic valve disease Aortic valve disease is common in an aging population. In a study of adults (mean age 58; range, 17 to 92) with a systolic murmur, 7 clinical cardiac examinations were reasonably accurate in diagnosing the etiology, with a diagnostic sensitivity of 71% for the detection of aortic stenosis. Nevertheless, in 27% of the patients with at least moderate aortic stenosis, cardiac exam missed the diagnosis or severely underestimated its severity. Similarly, in patients with combined aortic and mitral valve disease, aortic regurgitation or hypertrophic cardiomyopathy were frequently misdiagnosed on clinical examination alone. Thus, echocardiography should be performed in all patients with undiagnosed systolic murmurs, particularly older patients, who have a high prevalence of significant organic heart disease. Valve morphology can be readily defined with two-dimensional echocardiography as can the functional consequences of valve disease such as LV hypertrophy and systolic dysfunction. In the older population, calcific degenerative aortic valve disease is common and includes a spectrum of disease from aortic sclerosis to critical aortic stenosis. Aortic sclerosis, thickening and calcification of the leaflets without significant hemodynamic obstruction, is a progressive disease process that can be readily identified by echocardiography in approximately 25% of individuals greater than age 65 and in 55% of individuals greater than age 80. 8 Even in the absence of significant stenosis, aortic sclerosis may be a marker of advanced atherosclerosis, 9 may require antibiotic prophylaxis, and is associated with increased cardiovascular mortality and morbidity. 8 continued July 2003 Volume 58, Number 7 Geriatrics 31
CME Echocardiography Image courtesy of Barbara A. Berko, MD; Alyson N. Owen, MD; Donna R. Zwas, MD Figure 1. Spectral Doppler and two-dimensional image of a patient with severe aortic stenosis (peak gradient 124 mm Hg, mean gradient 78 mm Hg). Aortic valve area (AVA) is calculated using the continuity equation, which states that the product of area and velocity at the aortic valve level and at the left ventricular outflow tract (LVOT) level must be equal. Rearranging the equation allows for calculation of AVA as demonstrated. Doppler echocardiography has permitted the accurate quantification of aortic valve gradients and area in stenotic lesions, and can be used to monitor disease progression. 10 Excellent correlation has been found between the mean valve gradients measured by Doppler imaging and the directly measured catheter gradients. 11 The continuity equation, which assumes constant flow volume across the LV outflow tract and the stenotic valve, can be used to determine aortic valve area, and has provided excellent correlations with invasive measurements of valve area (figure 1). A mean transvalvular gradient 50 mm Hg, or a valve area <0.8 cm 2 correlate with severe stenosis. When severe aortic stenosis is present, surgery should be considered once symptoms develop. Even older patients experience significantly improved outcomes after valve replacement, despite having a higher perioperative mortality than younger patients. 12 Most cardiac surgeons now rely on Doppler-derived valve areas along with two-dimensional echo assessments of ventricular function to guide decisions regarding the appropriateness of valve replacement. Invasive cardiac catheterization is still required for evaluation for coronary artery disease, which coexists with valve disease in the majority of older patients. Mitral annular calcification Some degree of calcification of the mitral annulus (figure 2) is prevalent in older patients, increasing up to 45% in women greater than age 90. Mitral annular calcification is generally considered to be a benign finding, although it can be associated with mitral regurgitation, mitral stenosis, infective endocarditis, and atrial fibrillation. It has been associated with an approximate 2-fold increased risk of stroke with multiple mechanisms suggested. 13-15 Most likely, mitral annular calcification is associated with both coronary and carotid disease, as well as with aortic atheroma, and it is probably best thought of as a marker of more generalized atherosclerosis. Atrial fibrillation Atrial fibrillation has special relevance for the geriatric population, as it is predominantly an arrhythmia of older adults. It is a leading cause of stroke. The role of echocardiography in the management of atrial fibrillation includes: 1) establishing underlying cardiac abnormalities and diagnoses; 2) helping assess risk for stroke; and 3) helping assess the presence of left atrial appendage thrombus prior to cardioversion. Transthoracic echocardiography provides important information about underlying structural heart disease in patients with atrial fibrillation. The most common underlying disorder is hypertensive heart disease, manifested as left ventricular hypertrophy with associated left atrial enlargement. Older patients may develop left atrial enlargement even in the absence of hypertension due to abnormalities of diastolic function. Left atrial dimensions >5 cm are associated with a lower likelihood of the heart being able to restore and maintain normal sinus rhythm. The evaluation of left ventricular function and the presence of CAD are critical in the choice of antiarrhythmic therapy, as many antiarrhythmic medications are unsafe in patients with CAD, LV dysfunction, or both due to proarrhythmic effects. Assessing risk for stroke in patients with persistent atrial fibrillation is extremely important. Multiple studies have established the benefit of anticoagulation with warfarin for reducing atrial fibrillation-related-stroke by 80%. Numerous clinical and echocardiographic risk factors have been established that can identify patients at higher risk for embolic stroke, older age being one of the most important. Left ventricular dysfunction and in- 32 Geriatrics July 2003 Volume 58, Number 7
creased left atrial size detected on TTE also predict increased stroke risk. The addition of TEE allows for additional risk stratification. TEE allows the direct visualization of the left atrial appendage, which is the usual site of thrombus formation in atrial fibrillation and is not readily imaged with TTE. The contractile function of the left atrial appendage can be assessed as can the presence of spontaneous echo contrast, which are associated with a low flow state, and are predictors of thrombus formation. The role of echocardiography in the management of patients pericardioversion has been extensively investigated over the last 10 years. It has been wellestablished that embolism is a possible consequence of cardioversion. Conventional management of cardioversion includes anticoagulation with warfarin for 4 weeks prior to cardioversion to allow for resolution of existent thrombus, and continuation of anticoagulation for 4 weeks after cardioversion to prevent thrombus formation during the period of atrial stunning. Transesophageal echocardiography, which allows for visualization of the left atrial appendage and therefore of any existent left atrial appendage thrombus (figure 3), can be used if early cardioversion is required (with appropriate IV or subcutaneous anticoagulation), obviating the need for 4 weeks of prior anticoagulation. 16 www.geri.com Figure 2. Severe mitral annular calcification extending into the posterior leaflet of the mitral valve seen in the apical four chamber view (demonstrated by arrows). RV = right ventricle, LV = left ventricle, RA = right atrium, LA = left atrium. Stroke The majority of strokes occur in older patients. Both TTE and TEE are used to identify underlying etiologies of stroke, although their exact roles remain somewhat controversial. The yield of echo is highest when the clinical presentation clearly suggests an embolic event, present in 20% of ischemic strokes. Transthoracic echocardiography can identify possible embolic sources including left ventricular thrombi, intracardiac tumors (particularly atrial myxoma), valvular abnormalities such as bacterial or nonbacterial vegetations, and valvular strands or valvular tumors such as fibroelastoma. Transesophageal echocardiography increases identification of all these abnormalities, with the possible exception of left ventricular thrombus. The most important advantage of TEE over TTE is that TEE is better able to identify abnormalities of the interatrial septum particularly interatrial septal aneurysm, patent foramen ovale (PFO), and advanced aortic atheroma. Transesophageal echocardiography is also instrumental in the identification of left atrial/left atrial appendage thrombus. The role of the PFO in stroke in older patients remains controversial. Older patients have a higher stroke recurrence rate after PFO closure than do younger patients, suggesting that the identified PFO may have been only an incidental finding. 17 Therefore, the finding of a PFO as the only abnormality in a geriatric stroke patient should be viewed with caution as an etiologic finding. Complex aortic atherosclerosis has been well-established to have an independent association with stroke. Stroke risk increases with increasing thickness of the aortic plaque, with plaque thickness >4 mm demonstrating a strong association with stroke, and mobile plaque being highly associated with embolic stroke. 18 There is support from small observational studies and case studies for the treatment of protuberant, mobile, or ulcerated atheroma with warfarin rather than antiplatelet agents, but there are no large randomized studies that address therapy. 19 What then is the appropriate use of echocardiography in the older patient with new stroke? Most experts would proceed with a transthoracic echocardiogram, recognizing that the yield is low, particularly in the absence of clinical evidence to suggest underlying cardiac disease. Proceeding to TEE should July 2003 Volume 58, Number 7 Geriatrics 33 Image courtesy of Barbara A. Berko, MD; Alyson N. Owen, MD; Donna R. Zwas, MD
CME Echocardiography Image courtesy of Barbara A. Berko, MD; Alyson N. Owen, MD; Donna R. Zwas, MD Figure 3. Complex left atrial appendage seen on transesophageal echocardiography demonstrating a left atrial appendage thrombus (outlined with dotted line). depend in part on whether the information obtained would alter therapy. If a patient is not a candidate for full anticoagulation, identifying mobile aortic plaque will be only of academic interest. Conversely, in a patient with atrial fibrillation who will be treated with warfarin therapy, the actual identification of left atrial appendage thrombus will add little to the therapeutic decision. TEE would remain an important test if cardioversion was anticipated. Conclusion Echocardiography plays a major role in the diagnostic assessment and management of cardiovascular disease in older adults. It provides a wealth of information about the morphology, function, and physiology of cardiac structures, using noninvasive and portable techniques. This review has focused on the role of echocardiography in clinical syndromes frequently encountered in a geriatric population. G References 1. Sabia P, Abbott RD, Afrookteh A, Keller MW, Touchstone DA, Kaul S. Importance of two-dimensional echocardiographic assessment of left ventricular systolic function in patients presenting to the emergency room with cardiac-related symptoms. Circulation 1991; 84(4):1615-24. 2. Quinones MA, Verani MS, Haichin RM, Mahmarian JJ, Suarez J, Zoghbi WA. Exercise echocardiography versus 201 Tl single-photon emission computed tomography in evaluation of coronary artery disease. Circulation 1992; 85(3):1026-31. 3. Beleslin BD, Ostojic M, Stepanovic J, et al. Stress echocardiography in the detection of myocardial ischemia: Headto-head comparison of exercise, dobutamine, and dipyridamole tests. Circulation 1994; 90(3):1168-76. 4. Poldermans D, Arnese M, Fioretti PM, et al. Improved cardiac risk stratification in major vascular surgery with dobutamine-atropine stress echocardiography. J Am Coll Cardiol 1995; 26(3):648-53. 5. Senni M, Redfield MM. Congestive heart failure in elderly patients. Mayo Clin Proc 1997; 72(5):453-60. 6. Xie GY, Berk MR, Smith MD, Gurley JC, DeMaria AN. Prognostic value of Doppler transmitral flow patterns in patients with congestive heart failure. J Am Coll Cardiol 1994; 24(1):132-9. 7. Attenhofer Jost CH, Turina J, Mayer K, et al. Echocardiography in the evaluation of systolic murmurs of unknown cause. Am J Med 2000; 108(8):614-20. 8. Otto CM, Lind BK, Kitzman DW, Gersh BJ, Siscovick DS. Association of aorticvalve sclerosis with cardiovascular mortality and morbidity in the elderly. N Engl J Med 1999; 341(3):142-7. 9. Tolstrup K, Roldan CA, Qualls CR, Crawford MH. Aortic valve sclerosis, mitral annular calcium, and aortic root sclerosis as markers of atherosclerosis in men. Am J Cardiol 2002; 89(9): 1030-4. 10. Otto CM, Burwash IG, Legget ME, et al. Prospective study of asymptomatic valvular aortic stenosis: Clinical, echocardiographic, and exercise predictors of outcome. Circulation 1997; 95(9):2262-70. 11. Galan A, Zoghbi WA, Quinones MA. Determination of severity of valvular aortic stenosis by Doppler echocardiography and relation of findings to clinical outcome and agreement with hemodynamic measurements determined at cardiac catheterization. Am J Cardiol 1991; 67(11):1007-12. 12. Culliford AT, Galloway AC, Colvin SB, et al. Aortic valve replacement for aortic stenosis in persons aged 80 years and over. Am J Cardiol 1991; 67(15):1256-60. 13. Benjamin EJ, Plehn JF, D Agostino RB, et al. Mitral annular calcification and the risk of stroke in an elderly cohort. N Engl J Med 1992; 327(6):374-9. 14. Mouton P, Biousse V, Crassard I, Bousson V, Bousser MG. Ischemic stroke due to calcific emboli from mitral valve annulus calcification. Stroke 1997; 28(11):2325-6. 15. Eicher JC, Soto FX, DeNadai L, et al. Possible association of thrombotic, nonbacterial vegetations of the mitral ring-mitral annular calcium and stroke. Am J Cardiol 1997; 79(12):1712-5. 16. Klein AL, Grimm RA, Murray RD, et al. Use of transesophageal echocardiography to guide cardioversion in patients with atrial fibrillation. N Engl J Med 2001; 344(19):1411-20. 17. Homma S, DiTullio MR, Sacco RL, Sciacca RR, Smith C, Mohr JP. Surgical closure of patent foramen ovale in cryptogenic stroke. Stroke 1997; 28(12):2376-81. 18. Amarenco P, Cohen A, Tzourio C, et al. Atherosclerotic disease of the aortic arch and the risk of ischemic stroke. N Engl J Med 1994; 331(22):1474-9. 19. Tunick PA, Kronzon I. Atheromas of the thoracic aorta: Clinical and therapeutic update. J Am Coll Cardiol 2000; 35(3):545-54. 34 Geriatrics July 2003 Volume 58, Number 7
CME Geriatrics Exam Detach or photocopy this page, place an X in the boxes that correspond to your answers, fill in your name and address, and mail (see address below). Answers must be received by January 1, 2004. A score of at least 80% must be earned to receive CME credit. Make check for $15 payable to The Page and William Black Post-Graduate School and mail it with this exam to Rae Ann Houghton, Geriatrics, 7500 Old Oak Blvd., Cleveland, Ohio 44130. When submitting more than one exam, attach a separate check for $15 to each exam. Documentation of earned credit and the correct answers will be mailed to you. Allow up to 12 weeks for notification. Accreditation. This activity has been planned and implemented in accordance with the Essentials and Standards of the Accreditation Council for Continuing Medical Education (ACCME) through the sponsorship of Mount Sinai School of Medicine. Mount Sinai School of Medicine is accredited by ACCME to provide continuing medical education for physicians. Mount Sinai School of Medicine designates this continuing medical education activity for a maximum of 1 credit in category 1 toward the AMA Physician s Recognition Award. Each physician should claim only those hours that he/she spent in the educational activity. Faculty Disclosure. It is the policy of Mount Sinai School of Medicine to ensure fair balance, independence, objectivity, and scientific rigor in all its sponsored programs. All faculty participating in sponsored programs are expected to disclose to the audience any real or apparent conflict-of-interest related to the content of their presentation, and any discussions of unlabeled or investigational use of any commercial product or device not yet approved in the United States. Berko BA, Owen AN, Zwas DR. Echocardiography: The role of this noninvasive test in the geriatric population. Geriatrics 2003; 58(July):30-34. 1. Which of the following echocardiographic techniques supplies quantitative information about blood flow velocity within the heart? a. two-dimensional echocardiography b. spectral Doppler echocardiography c. color flow Doppler echocardiography 2. What percentage of people with congestive heart failure have been found to have normal left ventricular systolic function? a. 10 to 20% b. 20 to 30% c. 30 to 40% d. 40 to 50% e. 50 to 60% 3. Which mitral inflow spectral Doppler finding is associated with elevated left atrial pressure and a poor prognosis in patients with left ventricular systolic dysfunction? a. E/A reversal b. pseudonormalization c. restrictive inflow pattern 4. Which of the following statements about aortic sclerosis is true? a. it is found in 25% of patients over age 65 b. it is found in 55% of patients over age 80 c. it may be a marker of advanced atherosclerosis d. all of the above 5. The most likely relationship of mitral annular calcification to embolic stroke is through: a. embolization of calcific material b. embolization of superimposed thrombus c. association with more generalized atherosclerosis 6. Transesophageal echocardiography allows for early cardioversion of atrial fibrillation, with appropriate anticoagulation, if no left atrial appendage thrombus is identified. a. True b. False 7. Identification of significant aortic atherosclerosis is a possible etiologic finding in older patients with embolic stroke. a. True b. False 8. Which of the following statements is not true? a. Correlation of stress echocardiography with nuclear techniques and cardiac catheterization have been excellent. b. A negative dobutamine stress echocardiogram in a preoperative evaluation has a good negative predictive value. c. Dobutamine stress echocardiography can be used in patients who are unable to perform treadmill stress testing due to deconditioning, peripheral vascular disease, arthritis, or other comorbidities. d. Stress echocardiography has a sensitivity of greater than 90% for detecting single vessel coronary artery disease. In addition to the exam questions, answer the following evaluation questions: (1=strongly agree, 6=strongly disagree) 1. The information presented in this article was useful. 2. The information presented was fair, objective, and balanced. 1 2 3 4 5 6 1 2 3 4 5 6 Your name: Degree Address (Street): (City) (State) (Zip) Phone (include area code): Email: Specialty: GP FP IM DO Other (specify) Date: Signature: www.geri.com July 2003 Volume 58, Number 7 Geriatrics 35