Transthoracic echocardiography is particularly limited in the assessment of mechanical valve dysfunction because of acoustic shadow interference reflected by the mechanical prosthesis. Transesophageal echocardiography should be used in the assessment of suspected prosthetic valve dysfunction in the critically ill patients to identify the cause and allow possible intervention directed toward the prevention of additional sequelae. In cases of sudden and unexplained hemodynamic deterioration in patients with critical illness, TEE is useful for searching the underlying causes if TTE gave unsatisfactory results.
Recent reports have documented the greater accuracy of TEE for detecting left atrial appendage thrombus or spontaneous echo contrast that was the indicator of a higher risk for systemic embolization. Our experience in 11 patients revealed the potential cardiac source of embolism in nine patients by TEE, but in none of them by TTE. Although confirmatory tests were not performed in this group, the diagnostic yield of TEE in the detection of left atrial thrombi is high in our recent study, using surgicopathologic findings as the gold standard.
We found TEE to be extremely useful in the detection of vegetation and valve ring abscess associated with infective endocarditis. Two cases of aortic valve ring abscess were rapidly and clearly identified by TEE. Our data were consistent with previous studies that have emphasized the greater accuracy of TEE for detecting vegetation and valve ring abscess associated with infective endocarditis. However, only six patients with suspected infective endocarditis were studied and three patients were excluded from having infective endocarditis. Therefore, it was difficult to show significant difference between these two diagnostic modalities. Presentation and Treatment
To quantify the severity of mitral regurgitation is important in deciding whether mitral valve surgery is needed. Transthoracic echocardiography may underestimate the severity of mitral regurgitation and hence delay the surgical correction. Transesophageal echocardiography was superior to TTE in quantitative assessment of the severity of mitral regurgitation in selected cases, especially when the regurgitant jet was eccentric and narrow.
In conclusion, TEE was useful in the treatment of critically ill patients. The procedure was a safe, well-tolerated, and valuable diagnostic approach for the rapid detection of specific cardiac abnormalities in patients with critical illness. Transesophageal echocardiography should be considered in the treatment of critically ill patients, especially when TTE provided inadequate information. This technique will also play an important role in making accurate decisions for emergent surgical intervention in selected patients.