4D-transesophageal echocardiography and emerging imaging modalities for guiding mitral valve repair

Alison M Pouch, Benjamin M Jackson, Paul A Yushkevich, Joseph H Gorman, Robert C Gorman
2015 Annals of Cardiothoracic Surgery  
Perspective Two-dimensional transesophageal echocardiography (2D-TEE) had a transformative impact on surgical treatment of mitral valve pathology in the 1980s. 2D-TEE provided unprecedented, high-quality views of the mitral valve that enabled pre-operative repair strategizing and immediate post-operative assessment of repair efficacy. Several decades later, the commercialization of fourdimensional transesophageal echocardiography (4D-TEE) and other emerging imaging modalities such as 4D
more » ... tomography (4DCT) and cardiac magnetic resonance imaging (CMRI) potentiate yet another transformative phase in the practice of mitral valve repair surgery. Bypassing the "mental integration" step required for 2D image interpretation, these higher dimensional modalities provide a more intuitive, complete description of valve morphology and dynamics that can be leveraged as a tool for more effective surgical decision support. Current research shows that these modalities may enhance mitral valve repair outcomes in four ways: (I) by increasing the precision of mitral valve diagnostics in order to tailor the repair plan to an individual's valve pathology; (II) as a means of risk stratification to determine which patients might benefit from valve repair over valve replacement; (III) by predicting the outcome of a given repair technique using image-derived valve models as input to computational biomechanical analysis; and (IV) by optimizing annuloplasty ring design. Research highlights in each of these areas are given below. Increasing diagnostic precision Chandra and colleagues (1) have demonstrated that quantifiable morphological features derived from 4D-TEE analysis can effectively classify the etiology of degenerative mitral valve disease. Differentiation of patients with Barlow's disease and fibroelastic deficiency, which is often not straightforward, influences the anticipated complexity of repair-knowledge of which can facilitate an appropriate match between the patient's valve pathology and the skill set of the surgeon performing the repair. Optimizing this match may prevent patients with repairable valves (in the hands of a surgeon with subspecialty expertise) from undergoing unnecessary valve replacement (in the hands of a surgeon with a greater comfort level with this less preferred, yet simpler, operation). Risk stratification Levack et al. (2) have identified 4D-TEE derived mitral leaflet tethering indices that are predictive of repair failure in patients with ischemic mitral regurgitation, a disease associated with the highest rates of early (<6 months) moderate to severe disease recurrence. Image-based preoperative repair risk assessment can help identify patients who are better suited for valve replacement than valve repair and thereby decrease the number of operations these patients undergo to successfully treat mitral regurgitation. Predicting repair outcome Several research groups have demonstrated that threedimensional image-derived models of the mitral valve can be used as patient-specific, anatomically accurate input to computational biomechanical simulations. Such analyses can predict post-repair valve geometry or estimate stress distributions on the mitral leaflets. For example, Mansi
doi:10.3978/j.issn.2225-319x.2015.02.01 pmid:26539351 pmcid:PMC4598460 fatcat:6pjwbk4r6vfohcvhcknv4vesnq