Quantitative assessment of mechanical prosthetic valve area by 3-dimensional transesophageal echocardiography

Clinical application of three-dimensional echocardiography: past, present and future

Significant advances in three-dimensional echocardiography have made this modality a powerful diagnostic tool in the cardiology clinic. It can provide accurate and reliable measurements of chamber size and function, including the quantification of left ventricular mechanical dyssynchrony to guide patient selection for cardiac resynchron-isation therapy. Furthermore, three-dimensional echocardiography offers novel views and comprehensive anatomic definition of valvular and congenital abnormalities, improving diagnosis and preoperative planning. In addition, it is extremely useful in monitoring the effectiveness of surgical or percutaneous transcatheter interventions. As its efficacy for more and more clinical applications is demonstrated, it is clear that three-dimensional echocardiography has become part of the routine clinical diagnostic armamentarium. In this article, we describe the development of three-dimensional echocardiography over the last decades, review the scientific evidence for its current clinical use and discuss potential future applications. (Neth Heart J 2009;17:18-24.).

Three-dimensional in vivo characterization of calcification in native valves and in Freestyle versus homograft aortic valves

OBJECTIVE

This article describes a novel interactive method for quantitative evaluation of calcium deposits in the aortic valve by means of electron beam tomography data fusion technique.

METHODS

The technique relied on the use of hierarchic 3-dimensional free-form volume registration with fast global optimization between normally acquired and contrast-enhanced electron beam tomographic volume. A total of 66 contrast-enhanced electron beam tomographic scans of the aortic root were performed in 27 patients, 10 with native aortic valve disease (group A) and 17 from a prospective randomized trial of aortic root replacement (group B, 9 Freestyle grafts [Medtronic, Inc, Minneapolis, Minn] and 8 homografts). To validate the in vivo electron beam tomographic measurements, 5 patients from group A underwent electron beam tomographic scans before the operation and then had their own valves, explanted at the time of surgery, analyzed for calcium quantification by ex vivo electron beam tomography.

RESULTS

In group A, the mean (+/- SE) calcification score was 6560 +/- 2388, which correlated with peak gradients measured at echocardiography ( r = 0.93, P = .02). In group B, the mean (+/- SE) calcification score was 168 +/- 27, showing a tendency toward a lower calcification for Freestyle valves than for homografts at 2 years after implantation ( P = .052). A mean variability of 6% was found between in vivo electron beam tomographic scores of calcification and those measured on valve specimens after explantation.

CONCLUSION

We describe a novel method to characterize the degree and location of calcification in both native valves and postoperative valve implants. The technique may be useful in the management of patients with aortic valve disease and has potential as a screening tool for high-risk patients to diagnose early valve calcification and possibly institute corrective measures.