Delayed rupture of right coronary artery after directional atherectomy for bail-out.

nique (Table I). The differences of 2 mm Hg and 1 mm Hg in peak and mean gradients, respectively, were not considered to be of clinical significance. Subsequent cardiac catheterization performed 48 hours later confirmed a mean mitral prosthetic diastolic gradient of 13 mm Hg. The calculated mitral valve area was 0.7 cm2. The excised mitral valve prosthesis revealed extensively thickened and calcified leaflets that were restricted in motion (Fig. 3). This case report represents a feasibility study of transesophageal continuous-wave Doppler in the evaluation of mitral prosthetic stenosis. Transesophageal echocardiography is extremely well suited for the evaluation of mitral valve prosthetic structure and function.4-6 Acoustic shadowing from the metallic components of prosthetic valves can create great difficulties in imaging the atria1 surface of the prosthesis and the left atrium from the traditional transthoracic approach. These problems are clearly evident in the evaluation of mechanical prostheses, but the metallic frame of bioprostheses is a strong reflector of ultrasound as well. The advantages of transesophageal echocardiography over transthoracic echocardiography in the evaluation of mitral prostheses include the ability to identify small vegetations or thrombi, perivalvular or valvular regurgitation, spontaneous echo contrast of the left atrium, and left atria1 appendage thrombi.4-6 Left atria1 spontaneous echo contrast in this study was not seen on transthoracic examination, and has been implicated as an indicator of increased thromboembolic risk.6 Transesophageal continuous-wave Doppler now also allows for accurate measurement of the transvalvular gradients that were calculated from the modified Bernoulli equation. This may be especially valuable when a satisfactory transthoracic study cannot be obtained, such as in the immediate postoperative period or in patients with poor transthoracic windows. Transesophageal continuous-wave Doppler is a promising new technique in the evaluation of prosthetic mitral stenosis. Further studies are needed to define its broader diagnostic role in cardiovascular disease.