"Other imaging modalities including transthoracic echocardiography (TTE) and 3DTTE have not achieved comparable imaging quality compared to 3DTEE due to obvious technical limitations (limitations due to poor echo windows and inferior resolution)," Dr. Dominik Schlosshan from Prince of Wales Hospital, Sydney, told Reuters Health by email.
"So in my mind patients deserve the best imaging modality available if it can help decide if the patient can undergo a percutaneous treatment option under local anesthetic performed as a day case or requires open heart surgery and mitral valve replacement."
Dr. Schlosshan and colleagues compared 3D TEE mitral valve planimetry with conventional 2D techniques in 43 consecutive patients referred for echocardiographic assessment of rheumatic mitral stenosis and suitability for percutaneous mitral valvuloplasty.
Their report appears in the June JACC: Cardiovascular Imaging.
3D assessment was possible in all but two patients whose excessive mitral valve calcification precluded adequate image quality and mitral valve area determination.
In contrast, 2D mitral valve area assessment was possible in only 27 patients (63%). Image quality was inadequate in 10 patients, and short-axis views of the mitral valve were deemed technically insufficient in six patients.
Similarly, commissural evaluation was possible in all patients by 3D TEE, but in only 32 patients by 2D TTE.
Mitral valve area (MVA) was significantly lower by 3D TEE planimetry than by 2D planimetry or pressure half-time formula but marginally greater than by continuity equation.
Interobserver and intraobserver agreement for MVA by 3D planimetry was excellent.
"The central message of the study ... that the mitral valve orifice can be accurately recorded by 3D TEE is undoubtedly correct," writes Dr. Arthur E. Weyman from Massachusetts General Hospital, Boston, in a related editorial.
"Given the invasive nature of this procedure, it is unlikely that it would ever be seen as a primary method for assessing MVA. However, if TEE is being performed for another reason (e.g., to exclude left atrial appendage [LAA] thrombi, as in this case), then it is clear that the MVA and valve morphology can also be assessed," Dr. Weyman notes.
"It is well established in clinical guidelines that TEE (either 2D or 3D) is a prerequisite in patients referred for percutaneous mitral valvuloplasty (PMV) to exclude LAA clot, as LAA clot is an absolute contraindication to proceed to PMV," Dr. Schlosshan said.
"Another question is if 3D TEE offers advantages over 2DTEE. In my view 3D TEE does and will have a major role in the clinical management of patients with severe symptomatic mitral stenosis that are being considered for PMV or surgery. In particular it helps answer the important clinical question if the valve is amenable to PMV."
"I might add that in my view 3D TEE or 2D TEE should be reserved for patients that have had detailed clinical workup to establish that there is an indication to intervene on the stenosed mitral valve," Dr. Schlosshan said. "I agree it should not be used routinely for all patients with mitral stenosis. These patients can be assessed by TTE (2D and/or 3D)."
By Will Boggs MD
J Am Coll Cardiol Img 2011;4:580-588.
Last Updated: 2011-06-15 19:45:03 -0400 (Reuters Health)
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