Mapping of mitral regurgitant defects by cardiovascular magnetic resonance in moderate or severe mitral regurgitation secondary to mitral valve prolapse

Login or register to view PDF.

Pages

An advantage of CMR compared with TTE is that because there is no limitation of imaging windows the CMR mapping protocol enabled a complete and systematic assessment of the mitral valve in every patient. Contiguous slices perpendicular to the valve closure line were consistently and easily obtained producing a standardised data set for interpretation. The very high inter- and intra-observer agreement obtained reflect this. Acquisition of the mapping images was efficient, requiring on average 7 cine images, and between 5 to 10 minutes per patient.

In patients with mitral valve prolapse, CMR has an established role in the assessment of LV size and function and mitral regurgitation severity. Wit
the addition of mitral valve mapping, CMR can potentially provide a comprehensive assessment of mitral regurgitation secondary to mitral valve prolapse in patients undergoing evaluation for valve surgery.

Study limitations
A limitation of this study is that a gold standard mapping assessment, either operative findings or TOE imaging, was available in only one third of patients. A larger study with surgical and/or TOE corroboration is required to assess the accuracy of CMR in segmental mapping of mitral valve leaflet pathology.

The study cohort comprised patients with known mitral valve prolapse with at least moderate mitral regurgitation on prior echocardiography. The ability of systematic CMR assessment of the mitral valve to detect mitral regurgitation jet lesions or leaflet abnormalities in patients with mild mitral regurgitation or other leaflet pathologies was not examined. The utility of CMR in the evaluation of mitral regurgitation in patients with atrial fibrillation was not assessed. These patients were excluded due to concern regarding reduced image quality due to the irregular rhythm. In addition to mapping of the abnormal segments, mitral valve leaflet length, the presence of mitral annular calcification and the assessment of sub-valvular structures are often important in assessing the ability to repair the mitral valve. These parameters were not formally assessed in this study. Whilst CMR is likely to be useful for assessment of mitral leaflet length and potentially the three-dimensional relationships between leaflets and subvalvular structures, the assessment of calcification by CMR is poor.

Conclusion
In patients with mitral regurgitation due to mitral valve prolapse, assessment of the mechanism of mitral regurgitation, jet direction and systematic valve mapping using a simple and efficient CMR protocol is feasible and should be considered as part of the standard CMR examination in patients with mitral regurgitation. Further studies are required to evaluate whether CMR valve mapping could be an alternative when preoperative TOE mapping is required.

Abbreviations
TTE trans-thoracic echocardiogram, TOE trans-oesophageal echocardiogram, CMR  Cardiovascular Magnetic Resonance, AMVL  Anterior Mitral Valve Leaflet, PMVL Posterior Mitral Valve Leaflet

Competing interests
The author(s) declare that they have no competing interests.

Acknowledgements
The authors are grateful to Barbara Semb, Research Secretary, Green Lane Research and Education Fund, for secretarial assistance.

Pages

References
  1. Braunberger E, Deloche A, Berrebi A, Abdallah F, Celestin JA, Meimoun P, Chatellier G, Chauvaud S, Fabiani JN, Carpentier A: Very long-term results (more than 20 years) of valve repair with carpentier's techniques in nonrheumatic mitral valve insufficiency. Circulation 2001, 104:I8-11.
  2. Lee EM, Shapiro LM, Wells FC: Superiority of mitral valve repair in surgery for degenerative mitral regurgitation. Eur Heart J 1997, 18:655-663.
  3. Bonow RO, Carabello BA, Kanu C, de Leon AC Jr, Faxon DP, Freed MD, Gaasch WH, Lytle BW, Nishimura RA, O'Gara PT, et al.: ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (writing committee to revise the 1998 Guidelines for the Management of Patients With Valvular Heart Disease): developed in collaboration with the Society of Cardiovascular Anesthesiologists: endorsed by the Society for Cardiovascular Angiography and Interventions and the Society of Thoracic Surgeons. Circulation 2006, 114:e84-231.
  4. Monin JL, Dehant P, Roiron C, Monchi M, Tabet JY, Clerc P, Fernandez G, Houel R, Garot J, Chauvel C, Gueret P: Functional assessment of mitral regurgitation by transthoracic echocardiography using standardized imaging planes diagnostic accuracy and outcome implications. J Am Coll Cardiol 2005, 46:302-309.
  5. Foster GP, Isselbacher EM, Rose GA, Torchiana DF, Akins CW, Picard MH: Accurate localization of mitral regurgitant defects using multiplane transesophageal echocardiography. Ann Thorac Surg 1998, 65:1025-1031.
  6. Carpentier A: Cardiac valve surgery ├óÔé¼ÔÇ£ the French correction". J Thorac Cardiovasc Surg 1983, 86:323-337.
  7. Barlow JB, Pocock WA: Billowing, floppy, prolapsed or flail mitral valves? Am J Cardiol 1985, 55:501-502.
  8. Zoghbi WA, Enriquez-Sarano M, Foster E, Grayburn PA, Kraft CD, Levine RA, Nihoyannopoulos P, Otto CM, Quinones MA, Rakowski H, et al.: Recommendations for evaluation of the severity of native valvular regurgitation with two-dimensional and Doppler echocardiography. J Am Soc Echocardiogr 2003, 16:777-802.
  9. Grigioni F, Enriquez-Sarano M, Ling LH, Bailey KR, Seward JB, Tajik AJ, Frye RL: Sudden death in mitral regurgitation due to flail leaflet. J Am Coll Cardiol 1999, 34:2078-2085.

"