Percutaneous Mitral Valve Interventions: Overview of New Approaches
- Thu, 5/6/10 - 2:33pm
- 3 Comments
- 6011 reads
Abstract Percutaneous therapy has emerged over the past few years as a rapidly progressing field of development for the treatment of mitral regurgitation. Most of the new percutaneous approaches are modifications of previously-described surgical techniques that have been used for mitral valve repair for several decades. The main surgical approaches to mitral valve repair are annuloplasty and leaflet repair. Catheter-based devices mimic these surgical approaches with the aim of achieving outcomes similar to surgery, with less procedural morbidity and mortality as a consequence of their much less invasive nature. Some of these concepts include mitral valve annulosplasty via either the coronary sinus or directly from retrograde left ventricular access, and leaflet repair using modifications of the surgical edge-to-edge technique. Many of these percutaneous approaches have been accomplished with several devices and have been used with enough acute success to demonstrate proof of concept. Here, we will discuss these novel catheter-based therapies for the treatment of mitral regurgitation.
VASCULAR DISEASE MANAGEMENT 2010;7:E126–E134
Key words: mitral regurgitation, percutaneous valve repair, surgical valve repair, mitral annuloplasty
_______________________________________________________________________
Normal mitral valve closure, which prevents systolic backflow of blood into the left atrium during left ventricular systole, depends on the complex interaction of each of the components of the valve apparatus; the left atrial wall, annulus, mitral valve leaflets, chordea tendineae, papillary muscles and the left ventricle (LV).1,2 Abnormalities in the anatomy and function of any one of these components can lead to incompetence of the valve, resulting in mitral regurgitation (MR). Normal mitral valve closure is thought to be a passive process mediated by flow deceleration though the valve with generation of vortices on the ventricular side of the leaflets in conjunction with an adverse pressure gradient between the LV and left atrium.3–5 During systole, the mitral annulus moves toward the LV apex, whereas contraction of the LV myocardium underlying the posterior annulus results in a decrease in annular area by approximately 25%.6
When MR is caused by pathology specific to the valve leaflets such as myxomatous degeneration, it is referred to as degenerative MR. On the other hand, mitral regurgitation that is a consequence of ventricular or annular abnormalities including cardiomyopathy or left ventricular or papillary muscle dysfunction as a result of ischemia, is referred to as functional MR.
MR, a common finding, is clinically significant in part as a result of its detrimental effect on LV function. Patients with mild MR may remain asymptomatic for many years. However, moderate-to-severe MR leads to either gradual or, at times, acute ventricular dilation and contractile dysfunction with ultimate development of symptoms and left ventricular failure.7 In patients with symptomatic moderate-to-severe or severe MR, surgical intervention is recommended. Surgery is also recommended for asymptomatic patients with severe MR who have evidence of left ventricular dysfunction and/or new onset atrial fibrillation or pulmonary hypertension.8
The preferred surgical therapy for MR is mitral valve repair.9,10 Patients undergoing mitral valve repair have demonstrated improved short- and long-term outcomes compared to patients who receive valve replacement with mitral valve prosthesis in prior nonrandomized clinical experience.11 In spite of these more favorable results with repair and the obvious limitations of prosthetic valve replacement, mitral valve repair is still being performed in only about half of patients undergoing mitral valve surgery.12 For functional MR, the most common surgical intervention is annuloplasty.13 Annuloplasty for functional MR is usually performed in association with coronary artery bypass surgery. Degenerative MR is typically treated with leaflet repair, and has better long-term outcomes than isolated annuloplasty for functional MR.
These surgical procedures, though effective at reducing MR, are associated with the expected mortality and morbidity of open-heart surgery. Thus, the morbidity and mortality associated with open-heart surgery keeps many patients with clinically significant MR from receiving mitral valve surgery, especially when they are older or at higher risk for surgery. Thus, these basic surgical concepts of annuloplasty and leaflet repair have been adapted for the development of novel catheter-based percutaneous approaches with the goal of expanding the pool of patients who might benefit from a less invasive approach to a reduction in MR. Advances in both technique and development of novel devices have led to a variety of methods to treat MR using a percutaneous route (Table 1). Percutaneous approaches for mitral valve repair have been recently implemented in clinical trials for treatment of MR.
1. Perloff JK, Roberts WC. The mitral apparatus: Functional anatomy of mitral regurgitation. Circulation 1972;46:227.
2. Roberts WC. Morphologic features of the normal and abnormal mitral valve. Am J Cardiol 1983;51:1005–1028.
3. Lee CS, Talbot TL. A fluid-mechanical study of the closure of heart valves. J Fluid Mechanics 1979;91:41–63.
4. Bellhouse BJ, Bellhouse FH. Fluid mechanics of the mitral valve. Nature 1969;224:615.
5. Bellhouse BJ. Fluid mechanics of a model mitral valve and left ventricle. Cardiovasc Res 1972;6:199.
6. Ormiston JA, Shah PM, Tei C, et al. Size and motion of the mitral valve annulus in man. I. A two-dimensional echocardiographic method and findings in normal subjects. Circulation 1981;64:113–120.
7. Enriquez-Sarano M, Nkomo V, Mohty D, et al. Mitral regurgitation: Predictors of outcome and natural history. Ad Cardiol 2002;39:133–143.
8. Bonow RO, Carabello B, de Leon AC Jr, et al. Guidelines for management of patients with valvular heart disease: Executive summary. Circulation 1998;98:1949–1984.
9. Miller DC. Ischemic mitral regurgitation redux-to repair or replace? J Thoracic Cardiovasc Surg 2001;122:1059–1062.
10. Lawrie GM. Mitral valve repair vs replacement: Current recommendations and long-term results. Cardiol Clin 1998;16:437–448.
11. Enriquez-Sarano M, Schaff HV, Orszulak TA. Valve repair improves the outcome of surgery for mitral valve regurgitation: A multivariate analysis. Circulation 1995;91:1022–1028.
12. STS U.S. Cardiac Surgery Database. Mitral valve repair and replacement patients: incidence of complications summary. www.sts.org (accessed 2002).
13. Calafiore AM, Gallina S, Di Mauro M, et al. Mitral valve procedure in dilated cardiomyopathy: Repair or replacement? Ann Thorac Surg 2001;71:1146–1152.
14. Alfieri O, Maisano F, De Bonis M, et al. The double-orifice technique in mitral valve repair: A simple solution for complex problems. J Thoracic Cardiovasc Surg 2001;122:674–681.
15. Umana JP, Salehizadeh B, DeRose JJ, et al. “Bow-tie” mitral valve repair: An adjuvant technique for ischemic mitral regurgitation. Ann Thorac Surg 1998;66:1640–1646.
16. Maisano F, Schreuder JJ, Oppizzi M, et al. The double orifice technique as a standardized approach to treat mitral regurgitation due to severe myxomatous disease: Surgical technique. Eur J Cardiothorac Surg 2000;17:201–215.
17. Maisano F, Caldarola A, Blasio A, et al. Midterm results of edge-to-edge mitral valve repair without annuloplasty. J Thoracic Cardiovasc Surg 2003;126:1987–1997.
18. Fann JI, St Goar FG, Komtebedde J, et al. Beating heart catheter-based-edge-to-edge mitral valve procedure in a porcine model; efficacy and healing response. Circulation 2004;110:988–993.
19. Silvestry FE, Rodriguez Ll, Herrmann HC, et al. Echocardiographic guidance and assessment of percutaneous repair for MR with the Evalve MitraClip: Lessons learned from EVEREST I. J Am Soc Echocardiogr 2007;20:1131–1140.
20. Feldman T, Wasserman HS, Herrmann HC, et al. Percutaneous mitral valve repair using the edge-to-edge technique: Six-month results of the EVEREST Phase I Clinical Trial. J Am Coll Cardiol 2005;46:2134–2134.
21. Feldman T, Kar S, Rinaldi M, et al. Percutaneous mitral repair with the MitraClip system: Safety and midterm durability in the initial EVEREST cohort. J Am Coll Cardiol 2009;18;54:686–694.
22. Zoghbi WA, Enriquez-Sarano M, Foster E, et al. Recommendations for the evaluation of the severity of native valvular regurgitation with two-dimensional and Doppler echocardiography. J Am Soc Echocardiogr 2003;16:777–802.
23. Bonow RO, Carabello BA, Chaterjee K, et al. ACC/AHA 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. Circulation 2006;114:450–457.
24. Miller DC. Ischemic mitral regurgitation redux-to repair or to replace? J Thorac Cardiovasc Surg 2001;122:1059–1062.
25. Gillinov AM, Wierup PN, Blackstone EH, et al. Is repair preferable to replacement for ischemic mitral regurgitation? J Thorac Cardiovasc Surg 2001;122:1125–1141.
26. Lamas GA, Mitchell GF, Flaker GC, et al. Clinical significance of mitral regurgitation after acute myocardial infarction. Survival and ventricular enlargement investigators. Circulation 1997;96:827–833.
27. Trichon BH, O’Connor CM. Secondary mitral and tricuspid regurgitation accompanying left ventricular systolic dysfunction: Is it important, and how is it treated? Am Heart J 2002;144:373–376.
28. Blondheim DS, Jacobs LE, Kotler MN, et al. Dilated cardiomyopathy with mitral regurgitation: Decreased survival despite a low frequency of left ventricular thrombus. Am Heart J 1991;122:1468–1475.
29. Harris KM, Sundt TM 3rd, Aeppli D, et al. Can late survival of patients with moderate ischemic mitral regurgitation be impacted by intervention on the valve? Ann Thorac Surg 2002;74:1468–1475.
30. Wu AH, Aaronson KD, Bolling SF, et al. Impact of mitral valve annuloplasty on mortality risk in patients with mitral regurgitation and left ventricular systolic dysfunction. J Am Coll Cardiol 2005;45:381–387.
31. Mihaljevic T, Lam BK, Rajeswaran J, et al. Impact of mitral valve annuloplasty combined with revascularization in patients with functional ischemic mitral regurgitation. J Am Coll Cardiol 2007;49:2191–2201.
32. Liddicoat JR, Mac Neill BD, Gillinov AM, et al. Percutaneous mitral valve repair: A feasibility study in an ovine model of acute ischemic mitral regurgitation. Catheter Cardiovasc Interv 2003;60:410–416.
33. Kaye DM, Byrne M, Alferness C, Power J. Feasibility and short-term efficacy of percutaneous mitral annular reduction for the therapy of heart failure-induced mitral regurgitation. Circulation 2003;108:1795–1797.
34. Webb JG, Harnek J, Munt BI, et al. Percutaneous transvenous mitral annuloplasty: Initial human experience with device implantation in the coronary sinus. Circulation 2006;113:851–855.
35. Schofer J. Presentation, American College of Cardiology, 2008, Chicago, March.
36. Byrne MJ, Kaye DM, Mathis M, et al. Percutaneous mitral annular reduction provides continued benefit in an ovine model of dilated cardiomyopathy. Circulation 2004;110:3088–3092.
37. Dubreuil O, Basmadjian A, Ducharme A, et al. Percutaneous mitral valve annuloplasty for ischemic mitral regurgitation: First in man experience with a temporary implant. Cathet Cardiovasc Diagn 2007;69:1053–1061.
38. Feldman T. Percutaneous mitral annuloplasty: Not always a cinch. Catheter Cardiovasc Interv 2007;69:1062–1063.
39. Heuser RR, Witzel T, Dickens D, et al. Percutaneous treatment of mitral regurgitation: The QuantumCor system. J Interv Cardiol 2008;21:178–182.
40. Grossi EA, Goldberg JD, LaPietra A, et al. Ischemic mitral valve reconstruction and replacement: Comparison of long-term survival and complications. J Thorac Cardiovasc Surg 2001;122:1107–1124.
41. Grossi EA, Saunders PC, Woo YJ, et al. Intraoperative effects of the coapsys annuloplasty system in a randomized evaluation (RESTOR-MV) of functional ischemic mitral regurgitation. Ann Thorac Surg 2005;80:1706–1711.
42. Pedersen WR, Block PC, Feldman TE. The iCoapsys repair system for the percutaneous treatment of functional mitral insuffiency. Eurointervention 2006;1(Suppl A):A44–A48.
43. Pederson WR, Block P, Leon M, et al. iCoapsys mitral valve repair system: Percutaneous implantation in animal model. Catheter Cardiovasc Interv 2008;72:125–131.
44. Rogers JH, Macoviak JA, David A, et al. Percutaneous septal sinus shortening: A novel procedure for the treatment of functional mitral regurgitation. Circulation 2006;113:2329–2334.
45. Feldman T. Percutaneous valve repair and replacement: Challenges encountered, challenges met, challenges ahead. Circulation 2006;113:771–773.
46. Vassiliades TA, Block PC, Cohn LH, et al. Society of Thoracic Surgeons: American Association of Thoracic Surgery; Society of Cardiovascular Angiography and Intervention. The clinical development of percutaneous heart valve technology: A position statement of the Society of Thoracic Surgeons (STS), the American Association for Thoracic Surgery (AATS), and the Society of Cardiovascular Angiography and Intervention (SCAI). Catheter Cardiovasc Interv 2005;65:73–79.
47. Rosengart TK, Feldman T, Borger MA, et al. American Heart Association statement on percutaneous and minimally invasive valve procedures. Circulation 2008;117:1750–1767.
48. Feldman T, Leon MB. Prospects for percutaneous valve therapies. Circulation 2007;11:2866–2877.
Wow! That's a relaly neat answer!
Reply to this comment »Very true! Makes a change to see sonmoee spell it out like that. :)
Reply to this comment »Real brain power on display. Thanks for that ansewr!
Reply to this comment »Post new comment