Progression of aortic stenosis in 394 patients: relation to changes in myocardial and mitral valve dysfunction.

OBJECTIVES: This study reports the results of echocardiographic follow-up in a large cohort of patients with aortic stenosis and correlates the progression of aortic stenosis with changes in the degree of mitral regurgitation and left ventricular hypertrophy and systolic dysfunction. BACKGROUND: Progressive aortic stenosis often causes left ventricular dysfunction and mitral regurgitation. Doppler echocardiography has greatly assisted in the noninvasive evaluation and follow-up of aortic stenosis. Nevertheless, the longitudinal follow-up of patients with Doppler echocardiography for the progression of aortic stenosis and the significance of progressive ventricular hypertrophy and mitral regurgitation have not been reported. METHODS: Serial Doppler echocardiography was performed in 394 consecutive patients with valvular aortic stenosis at baseline and after a mean follow-up period of 37 +/- 16 months. Mean and peak aortic gradients, aortic valve area, left ventricular systolic and diastolic diameters and percent area change (shortening fraction) were expressed as continuous variables, and systolic dysfunction, mitral regurgitation, ventricular hypertrophy and filling properties were tabulated as categoric variables using a semiquantitative grading system. RESULTS: Peak and mean gradients increased by an average of 8.3 and 6.3 mm Hg/year, respectively; end-systolic and end-diastolic diameters increased by 1.9 and 1.6 mm/year, respectively; and aortic valve area decreased by 0.14 cm2/year during the follow-up interval (p < 0.001 for all), indicating progression of aortic stenosis and ventricular dilation. Patients in the lowest quartile of aortic valve area and highest quartiles of mean and peak gradients had the least change compared with those in the highest quartile of aortic valve area and lowest quartile of mean and peak gradients (p < 0.01 for all). Patients with more mitral regurgitation at follow-up than at baseline had higher mean percent increase in mean and peak gradients as well as more progression of ventricular dilation and worsening systolic function compared with those with stable or improving mitral regurgitation (p < 0.05 for all). Similarly, subjects with worsening left ventricular hypertrophy had larger mean percent increase in mean and peak gradients than those with stable left ventricular hypertrophy (p < 0.01) but maintained stable ventricular volumes and systolic function. There was no correlation between the amount of change in mean or peak gradients and degree of deterioration in systolic function. CONCLUSIONS: Aortic stenosis progresses predictably over time; however, systolic dysfunction is an inconsistent marker of the hemodynamic consequences of severe aortic stenosis. As an adaptive response to pressure overload, progressive hypertrophy appears to prevent ventricular dilation and development or worsening of mitral regurgitation. Conversely, progressive mitral regurgitation may be seen as a maladaptive consequence of increasing aortic stenosis.

Benefits of intraoperative echocardiography in the surgical management of hypertrophic cardiomyopathy.

OBJECTIVES: The purpose of this study was to determine the role of intraoperative echocardiography in planning the site and extent of myectomy and in ensuring adequate control of the left ventricular outflow tract gradient. BACKGROUND: Although intraoperative echocardiography has been found to be beneficial in patients undergoing valve repair, its impact on surgical decisions in patients undergoing septal myectomy for hypertrophic cardiomyopathy has not been described. METHODS: In 50 patients undergoing septal myectomy over a 5-year period, epicardial echocardiography was performed before cardiopulmonary bypass to establish the extent of outflow tract obstruction, locate its site and plan the myectomy. In 30 patients, transesophageal echocardiography was also used to corroborate data on outflow tract anatomy and examine the mitral valve. RESULTS: In 40 patients (80%) the initial myectomy resulted in a reduction of the maximal outflow tract gradient from 88 +/- 45 to 24 +/- 11 mm Hg, measured by epicardial continuous wave Doppler echocardiography. Ten patients (20%) were shown by postbypass intraoperative echocardiography to have an unsatisfactory result, based on a persistent gradient > 50 mm Hg (n = 7) or persistent mitral regurgitation of greater than moderate severity (n = 3). The postbypass two-dimensional echocardiogram was then used to direct the surgeon toward the most likely site of continued obstruction, and cardiopulmonary bypass was reinstituted to permit further myectomy (n = 9) or mitral valve repair (n = 1). After the second or subsequent period of cardiopulmonary bypass, the outflow tract gradient (26 +/- 14 mm Hg) was substantially reduced and was not significantly different from the postbypass gradient (24 +/- 11 mm Hg) in the group with initial surgical success. At postoperative follow-up (20 +/- 37 weeks), the maximal measured outflow tract gradient (22 +/- 21 mm Hg) showed no difference between patients with immediate surgical success and those requiring a second period of cardiopulmonary bypass for further resection. CONCLUSIONS: Intraoperative echocardiography proved a useful tool to guide the site and extent of septal myectomy, leading to more adequate surgical resection and to persistence of satisfactory control of the outflow tract obstruction into the early follow-up period.

Transesophageal echocardiographic assessment of aortic coarctation using color, flow-directed Doppler sampling.

We report the use of color, flow-directed transesophageal Doppler in the evaluation of aortic coarctation. Transesophageal echocardiography (TEE) was used to define the aortic shelf in two adults with mild and moderate postductal coarctation, respectively. The color mosaic pattern aided in identification of the coarctation location and orifice diameter. Continuous wave and pulsed cursors were steered to provide sampling parallel to the color jet direction and gradients calculated by the modified Bernoulli formula, excluding prestenotic velocities. Measured pressure gradients were equivalent to those determined at catheterization. We conclude that color, flow-directed TEE Doppler sampling can aid in the identification and characterization of adult patients with aortic coarctation.

Color Doppler and two-dimensional echocardiographic determination of the mechanism of aortic regurgitation with surgical correlation.

The character of the color flow Doppler jet provides information on the mechanism and pathologic elements of valve dysfunction. This has been useful in the evaluation of mitral regurgitation, a repairable problem, but has not been described comprehensively for the aortic valve. The purpose of our study was to correlate the color flow Doppler characteristics of the aortic regurgitant jet and two-dimensional echocardiographic findings of valve mobility with surgical pathology. Prepump intraoperative echocardiography and color flow Doppler echocardiography were performed on 124 patients with aortic regurgitation and used to categorize leaflet motion as excessive, restricted, or normal, jet direction as eccentric or central, and jet origin between the cusps as eccentric, central, or diffuse. Bicuspid disease and tricuspid aortic valve prolapse were associated with excessive valve mobility and eccentric jet direction and origin. Conversely, annular dilation, rheumatic disease, sclerosis, and perforation were associated with normal or reduced cusp mobility and a central jet direction and origin (p = 0.001). Overall, an eccentric jet direction occurred in 69% of patients with excessive cusp mobility, whereas 71% of patients with normal or reduced cusp mobility had a central jet (p = 0.001). Therefore color flow Doppler determination of the eccentricity of regurgitant jet direction and origin is useful in predicting the mechanism and disease of aortic valve dysfunction. These observations may suggest the presence of prolapse and thus the potential for aortic valve repair.

Importance of sampling both pulmonary veins in grading mitral regurgitation by transesophageal echocardiography.

Pulmonary venous flow patterns have been used to assess severity of mitral regurgitation; however, the issue of which pulmonary veins to sample has not been determined. We performed pulsed wave Doppler transesophageal echocardiography of both the left and right upper pulmonary veins in 80 patients who had mitral regurgitation determined by independent transesophageal echocardiography color flow mapping. Pulmonary venous flow patterns, peak systolic and diastolic flow, and the presence of reversed systolic flow were compared between the left and right pulmonary veins for each grade of mitral regurgitation. Flow patterns were discordant in 20 (25%) of the 80 patients. Of the 43 patients with 4+ mitral regurgitation, there was discordant flow in 16 (37%) of the patients with mainly reversed systolic flow in the right upper vein, while there was blunted or normal systolic flow in the left upper vein. Of the 16 patients with discordant flows, 14 had eccentric jets, mainly anteromedial jets. We conclude that if discordant flow can occur in 25% of patients with mitral regurgitation and in 37% of patients with 4+ mitral regurgitation, then both pulmonary veins must be evaluated when assessing the severity of mitral regurgitation with pulsed wave Doppler transesophageal echocardiography.