Is cardiac catheterization necessary in the era of echocardiography? Cost-effective approach combining echocardiography and cardiac catheterization

The role of echocardiography in the evaluation and management of aortic stenosis in the older adult

Aortic stenosis is currently the most predominant valvular pathology in older adults. Signs and symptoms of aortic stenosis in this age-group may be difficult to recognize due to the decreased activity associated with aging and attribution of symptoms to other conditions. Echocardiography can be very helpful in the assessment of valvular structure and real time hemodynamic evaluation as well as in the progression of the disease over time. Unprecedented advances in echocardiography, including real time three-dimensional echocardiography, facilitate a comprehensive assessment of this condition and help in the decision-making process. Recent innovations in the percutaneous treatment of valvular diseases promise a revolution in the treatment of aortic stenosis especially in older adults.

Aortic Stenosis: The Role of Transesophageal Echocardiography

Noninvasive assessment of aortic valve area by echocardiography has become the standard of practice over the past few years. The advent of transesophageal echocardiography (TEE) has provided a new method for the assessment of aortic valve area (AVA) using planimetry by two-dimensional imaging. Clear visualization of the anatomy of the valve, as well as accuracy of AVA assessment, makes TEE an invaluable tool for the evaluation of aortic valve stenosis. TEE is especially helpful in clinical settings when there is a discrepancy between the AVA obtained by transthoracic echocardiography and cardiac catheterization. TEE is particularly helpful in the assessment of the aortic valve during intraoperative echocardiography. This review discusses the techniques, imaging planes, and details for assessing AVA by TEE. The role of TEE in AVA assessment is described, with specific clinical case examples cited.

Comparative value of Doppler echocardiography and cardiac catheterization in the decision to operate on patients with aortic stenosis

With the use of Doppler echocardiography, severity of valvular stenosis, etiology and type of valve lesions, and left ventricular function can be assessed accurately in patients with aortic stenosis. The purpose of this study was to compare the value of noninvasive clinical and Doppler echocardiographic findings, with cardiac catheterization, in the management decision-making for patients with aortic stenosis. One hundred and seventy consecutive patients with aortic stenosis who underwent cardiac catheterization and Doppler echocardiography were prospectively studied. A decision to operate, not operate or remain uncertain was made independently by experienced cardiologists given clinical information in combination with either Doppler echocardiographic (group I) or cardiac catheterization (group II) data. The severity of aortic stenosis agreed between Doppler echocardiography and cardiac catheterization in 168 patients (98.8%), and disagreed in two patients. There was agreement on clinical decision to operate or not operate between Group I and Group II in 160 patients (94.1%) and a discrepant decision in only two patients (1.1%). In eight patients (4.7%) with poor echogenecity or with discordance between clinical and echocardiographic data, the decision made by group I remained uncertain. We conclude that in a large majority of patients with aortic stenosis, Doppler echocardiographic assessment provides the same management decision reached by cardiac catheterization findings.

Use of transesophageal echocardiography to predict significant coronary artery disease in aortic stenosis

STUDY OBJECTIVES

This study was conducted to examine if the use of multiplane transesophageal echocardiography (TEE) could predict the absence or the presence of significant coronary artery disease (CAD) in patients with aortic stenosis.

DESIGN

Prospective study.

SETTING

University hospital.

PATIENTS

Clinical, angiographic features and TEE findings were prospectively analyzed in 132 consecutive patients with aortic stenosis.

MEASUREMENTS AND RESULTS

In 63 patients with significant CAD, 57 had thoracic aortic plaque on TEE studies. In contrast, aortic plaque existed in only 19 of the remaining 69 patients with normal or mildly abnormal coronary arteries. Therefore, the presence of aortic plaque on the TEE identified significant CAD with a sensitivity of 90.5%, a specificity of 72.5%, and with positive and negative predictive values of 75.0% and 89.3%, respectively. There was a significant relation between the severity of thoracic aortic atherosclerosis and the severity of CAD (p<0.0001). Multivariate logistic regression analysis revealed that aortic plaque, angina, and age were independent predictors of CAD. Aortic plaque was the most significant independent predictor.

CONCLUSION

This prospective study indicates that TEE examination of thoracic atherosclerotic plaque is a powerful predictor of absence of significant CAD in patients with aortic stenosis.

Multiplane transoesophageal echocardiographic detection of thoracic aortic plaque is a marker for coronary artery disease in women

OBJECTIVE

This study was conducted to examine if the multiplane transoesophageal echocardiographic detection of atherosclerotic plaque in the thoracic aorta could predict the absence or the presence and the severity of significant coronary artery disease in women. Its association with coronary disease is attractive and may have great influence on foregoing routine preoperative cardiac catheterization in patients with valvular heart disease but no data are available in women.

METHODS

Clinical and angiographic features and transoesophageal echocardiographic findings were prospectively analysed in 111 women.

RESULTS

In 24 women with significant coronary disease, 20 had thoracic aortic plaque on transoesophageal echocardiographic studies. In contrast, aortic plaque existed in only 12 of the remaining 87 women with normal or mildly abnormal coronary arteries. Therefore, the presence of aortic plaque had a sensitivity of 83%, a specificity of 86%, a positive and negative predictive values of 62% and 95%, respectively for the detection of significant coronary disease. There was a significant relation between the severity and the extent of atherosclerotic lesions and the angiographic coronary score (P<0.0001). Multivariate logistic regression analysis revealed that aortic plaque was the most significant independent marker of coronary disease (odds ratio=27.9; 95% confidence interval=5.5-131.6; P<0.0001).

CONCLUSIONS

This prospective study indicates that multiplane transoesophageal echocardiographic examination of thoracic atherosclerotic plaque is a marker for coronary disease in women and especially a powerful predictor of absence of significant coronary artery disease. Transoesophageal echocardiographic aortic examination might be used with risk factors and angina symptoms to discuss the need for preoperative coronary angiography in women with valvular heart disease.

Applying principles of pharmacoeconomic evaluation to perflenapent emulsion, a new echocardiographic contrast agent for use in cardiac function testing

A pharmacoeconomic evaluation was performed to determine the cost-effectiveness of perflenapent emulsion, a new contrast agent for use in echocardiography. A decision tree analysis was performed on data from the charts of 108 patients who had undergone stress echocardiography without contrast enhancement as part of a cardiac function or wall-motion study. An analysis of a theoretical cohort of patients was conducted to determine shifts in cost associated with enhancement of stress echocardiography with perflenapent emulsion. Outcome was determined by the point at which the clinician was able to determine a treatment course for the patient based on the diagnostic information given. Stress echocardiography without contrast was identified as the most cost-effective path in terms of a conclusive test. Perflenapent emulsion shows a positive cost impact in patients who have had an inconclusive stress echocardiogram without the use of a contrast agent. These results are supported by a sensitivity analysis across a wide range of pricing for perflenapent emulsion, a wide range of cost for a stress echocardiogram, and up to 99% efficacy of contrast-enhanced stress echocardiography.

Experimental analysis of fluid mechanical energy losses in aortic valve stenosis: importance of pressure recovery

Current methods for assessing the severity of aortic stenosis depend primarily on measures of maximum systolic pressure drop at the aortic valve orifice and related calculations such as valve area. It is becoming increasingly obvious, however, that the impact of the obstruction on the left ventricle is equally important in assessing its severity and could potentially be influenced by geometric factors of the valve, causing variable degrees of downstream pressure recovery. The goal of this study was to develop a method for measuring fluid mechanical energy losses in aortic stenosis that could then be directly related to the hemodynamic load placed on the left ventricle. A control volume form of conservation of energy was theoretically analyzed and modified for application to aortic valve stenosis measurements. In vitro physiological pulsatile flow experiments were conducted with different types of aortic stenosis models, including a venturi meter, a nozzle, and 21-mm Medtronic-Hall tilting disc and St. Jude bileaflet mechanical valves. The energy loss created by each model was measured for a wide range of experimental conditions, simulating physiological variation. In all cases, there was more energy lost for the nozzle (mean = 0.27 J) than for any other model for a given stroke volume. The two prosthetic valves generated approximately the same energy losses (mean = 0.18 J), which were not statistically different, whereas the venturi meter had the lowest energy loss for all conditions (mean = 0.037 J). Energy loss correlated poorly with orifice pressure drop (r2 = 0.34) but correlated well with recovered pressure drop (r2 = 0.94). However, when the valves were considered separately, orifice and recovered pressure drop were both strongly correlated with energy loss (r2 = 0.99, 0.96). The results show that recovered pressure drop, not orifice pressure drop, is directly related to the energy loss that determines pump work and therefore is a more accurate measure of the hemodynamic significance of aortic stenosis.