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Three Part Question

In [patients with mitral regurgitation secondary to degenerative mitral valve disease requiring a mitral valve repair with an annuloplasty ring] is a [flexible ring superior to a semi-rigid or rigid ring] in terms of [improvement in symptoms and survival]?

Clinical Scenario

Your consultant is about to operate on a 48-year-old patient with moderate to severe mitral regurgitation (MR) due to degenerative disease of the mitral valve. The scrub nurse asks you about the type of ring that your boss is going to use. You say that he always uses a flexible ring. She asks you why and your boss overhears your rather unconvincing response and suggests that you go and look up the evidence rather than cannulating today.

Search Strategy

Medline from 1950 through January 2008 using Ovid interface.

Mitral valve repair.mp OR mitral valve reconstruction.mp OR mitral valvuloplasty.mp] AND [Annuloplast$.mp OR valvuloplast$.mp] AND [Exp survival OR exp outcome OR outcome$.mp].

Search Outcome

The ‘related articles’ function was used to broaden the search and all abstracts, studies, and citations scanned were reviewed. The reference lists of articles found through these searches were also reviewed for relevant articles. Only studies recruiting patients with MR secondary to degenerative mitral disease were included.

A total of 478 papers were found using the search strategy. Twelve papers were deemed to represent the best evidence on the topic and are summarised in the Table

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Borghetti et al, 2000, Italy	44 patients undergoing mitral valve repair for degenerative MR Autologous pericardial flexible ring (Group I) = 23 patients Carpentier rigid ring (Group II) = 21 patients	Retrospective study (level 2b)	Postop MR	No significant MR at rest or exercise in any patient	Small sample size No clinical outcomes Retrospective study Non-randomized Direct vizualization of mitral annular dynamics was not performed 2D echocardiography used which does not give three-dimensional reconstruction of the mitral valve the gold standard for postoperative evaluation of functional or anatomical details of the valvular apparatus after mitral valve repair
			MASE	Better MASE at all the studied longitudinal segments at rest and during exercise only in Group I
			TMFW	Significant increase in both groups (P<0.0001)
			Group I	From 1.22±0.22 to 1.79±0.32 m/s, t=–8.8, P<0.0001
			Group II	From 1.19±0.17 to 1.96±0.33 m/s, t=–12.8, P<0.0001
			Recruitment of LVEF reserve during exercise	Significant only in Group I
			Group I	From 59.5±6% to 65.8±6%, t=–3.95, P<0.005
			Group II	No change
Dall'Agata et al, 1998, The Netherlands	19 patients undergoing mitral valve repair for degenerative MR Cosgrove-Edwards flexible ring =15 patients. Carpentier rigid ring =4 patients	Case control study (level 3b)	Ring annular area	Signicant change in the orifice area observed only in Cosgrove-Edwards flexible ring (P<0.0001)	Small sample size Non-randomised No clinical outcomes
			Cosgrove-Edwards flexible ring	Systolic 4.21±1.50 cm2 Diastolyic 4.81±1.56 cm2
			Carpentier rigid ring	Systolic 3.80±0.77 cm2 Diastolyic 3.74±0.89 cm2
			Ring AP diameter	Significant change in the AP diameter observed only in Cosgrove-Edwards flexible ring (P<0.01)
			Cosgrove-Edwards flexible ring	Systolic 1.92±0.27 cm Diastolic 2.05±0.22 cm
			Carpentier rigid ring	Systolic 1.77±0.20 cm Diastolic 1.70±0.20 cm
			Ring transverse diameter	No significant change in transverse diameter for both rings
			Cosgrove-Edwards flexible ring	Systolic 2.45±0.48 cm Diastolic 2.50±0.57 cm
			Carpentier rigid ring	Systolic 2.60±0.34 cm Diastolic 2.57±0.42 cm
Yamaura et al, 1997, Japan	20 patients undergoing mitral valve repair for degenerative MR Carpentier rigid ring = 10 patients Duran flexible ring = 10 patients	Case control study (level 3b)	Mitral annular configuration	Carpentier ring planar Duran ring Non-planar	Small sample size Non-randomized No clinical outcomes
			Change in mitral annular area during cardiac cycle	Significant change only in Duran ring
			Carpentier ring	Unchanged
			Duran ring	25±2% reduction
Okada et al, 1995, Japan	26 patients undergoing mitral valve repair for degenerative MR Carpentier ring = 11 patients Duran flexible ring = 15 patients	Case control study (level 3b)	LV systolic function	Similar	Small sample size Non-randomized No clinical outcomes LV systolic function measured at coronary angiography
			Change in mitral annular area during cardiac cycle	Significant change only in Duran ring
			LV fractional shortening	Significant difference Carpentier ring 35.8% Duran ring 43.4%
			Peak velocity at peak exercise	Significant difference Carpentier ring 222 cm/s Duran ring 186 cm/s
Yamaura et al, 1995, Japan	10 patients undergoing mitral valve repair for degenerative MR Carpentier rigid ring = 5 patients Duran flexible ring = 5 patients Normal subjects = 5 patients	Case control study (level 3b)	LV systolic function		Small sample size Non-randomised No clinical outcomes
			Change in mitral annular area during cardiac cycle
			LV fractional shortening
			Peak velocity at peak exercise
Unger-Graeber et al, 1991, USA	122 patients undergoing mitral valve repair Carpentier rigid ring = 46 patients Duran flexible ring = 48 patients No ring = 28 patients	Case control study (level 3b)	Decrease in mitral valve area	Significant decrease in mitral valve area only in patients with rings (P=0.01)	Non-randomized No clinical outcomes Heterogenous causes of MR although 72 patients had degenerative MR Only Doppler echocardiography used
			Carpentier ring	2.6±0.8 cm2
			Duran ring	2.8±0.8 cm2
			No ring	3.2±0.7 cm2
			Peak transmitral diastolic velocity	Similar
			Peak transmitral diastolic gradient	Similar
			Grade of mitral regurgitation	Similar
David et al, 1989, Canada	25 patients undergoing mitral valve repair for degenerative MR Rigid ring = 13 patients Flexible ring = 12 patients	RCT (level 1b)	Reduction in LVEDD	Similar	Sample size No clinical outcomes
			Reduction in LVEDV	Similar
			Reduction in LVESD	Significant reduction only in flexible ring group (P<0.05)
			Reduction in LVESV	Significant reduction only in flexible ring group (P<0.05)
			LV systolic function	Significantly better in patients with a flexible ring (P<0.02)
			LV performance measured by stroke volume end-diastolic volume relationships	Significantly better in patients with a flexible ring (P<0.05)
Chung et al, 2007, Korea	294 patients undergoing mitral valve repair for degenerative MR Carpentier rigid ring = 153 patients Duran flexible ring = 141 patients	Retrospective study (level 2b)	Overall survival	Similar	Retrospective study Non-randomised
			Reoperation-free survival	Similar
			Five year MR (grade ≥3) – free survival	Similar (P=0.83) CE group 75.1±4.6% Duran group 82.4±4.5%
			Five year MS (MPG ≥10 mmHg) – free survival rate	Overall superior five-year MS-free survival for CE group (P=0.011) CE group 91.2±2.8% 65.1±10.7%
			MPG ≥10 mmHg	Significantly more Duran patients had an MPG of ≥10 mmHg
			Change in LV ejection fraction LV mass and LV dimensions	No change over time in either group
			LV mass and LV dimensions	LV mass and LV dimensions decreased significantly after surgery in both groups, but no significant inter-group difference was seen for either index
Chang et al, 2007, Korea	356 patients undergoing mitral valve repair Carpentier rigid ring = 186 patients Duran flexible ring = 170 patients	RCT (level 1b)	Operative/early death	4 (1.1%) CE 0, Duran 4	Heterogenous causes of MR although 236 patients had degenerative MR
			Late death	21 (5.8%) CE 11, Duran 10
			Survival rate	Similar (P=0.74)
			5-year survival	93.3±1.7% CE 95.6±1.7%, Duran 91.4±2.8%
			10-year survival	77.4±8.0% CE 85.9±4.9%, Duran 75.7±7.2%
			Significant MR (grade ≥3)	23 patients CE 8, Duran 15
			Reoperation	8 patients
			Progression of MR necessitating reoperation	5 patients CE 1, Duran 5
			10-year freedom from anticoagulation-related haemorrhage	99.1±0.7% (P=0.16) CE 100%, 98.2±1.3%
			10-year freedom from infective endocarditis	98.6±0.9% (P=0.56) CE 98.7±0.9%, 98.6±1.4%
			Preop LVEF	CE 62.5±11.8%, Duran 63.2±11.9%
			Postop LVEF	Significant but similar change for both groups (P<0.001), CE 55.9±13% , Duran 56.5±14.1%
			Preop LVESD	CE 46.2±11.7 mm, Duran 45.8±11.9 mm
			Postop LVESD	Significant but similar change for both groups (P<0.001), CE 42.1±10.1 mm, 41.2±10.5 mm
			Preop LVEDD	CE 58.3±12.3 mm, 59.4±11.7 mm
			Postop LVEDD	Significant but similar change for both groups (P<0.001), CE 48.6±10.3 mm, Duran 50.6±9.1 mm
			Preop LAD	CE 51.1±9.1 mm, Duran 52.8±11.2 mm
			Postop LAD	Significant but similar change for both groups (P<0.001), CE 44±8.6 mm, Duran 45.3±9.4 mm
Shahin et al, 2005, The Netherlands	96 patients undergoing mitral valve repair CE Classic rigid ring = 53 patients CE Physio flexible ring = 43 patients	RCT (level 1b)	Mortality	16% difference in mortality (P=0.41), Physio group (n) 6, Classic group (n) 16	Analyses were adjusted for age and gender, and for factors that differed across groups at baseline
			Intra-operative repair failure	7, Physio group 3, Classic group 4
			Late failure	5, Physio group 4, Classic group 1
			LV function	LV function did not differ across groups (P=0.65), Physio 48%, Classic group 45%
			Improvement in combined NYHA class III-IV	Similar improvement, Physio group 34%, Classic group 42%
Bevilacqua et al, 2003, Italy	133 patients undergoing mitral valve repair for degenerative MR Carpentier rigid ring = 77 patients Autologous pericardial ring = 56 patients	Retrospective study (level 2b)	30-day mortality	3.8% (P>0.999), Prosthetic ring group (n) 3, Pericardial ring group (n) 2	Retrospective study Bias related to learning curve as kind of implanted annuloplasty ring was not randomly assigned but varied during the study period Confounding factors such glutaraldehyde fixation (time and concentration), pericardial ring modeling and implantation could be related to the unsatisfactory durability of pericardial ring
			SAM	5.2% (P=0.083), Prosthetic ring group 4, Pericardial ring group 0
			Five-year freedom from reoperation and recurrence of mitral regurgitation=≥3+/4+	Significantly higher in the prosthetic ring group (P=0.027), Prosthetic ring group 90.1% – CL90%: 81.9–98.3%, Pericardial ring group 62.6% – CL90%: 43.1–82.1%
			Reoperation for recurrent mitral regurgitation at 16.7±15.6 months	11 patients (P=0.005), Prosthetic ring group 2, Pericardial ring group 9
			Five-year freedom from death	93.3% (CL90%: 90.5–96.2%). The kind of annuloplasty ring showed no influence on long-term survival (P=0.519). Prosthetic ring group 95.8%; CL90%: 91.8–99.7%, Pericardial ring group 91.0; CL90%: 83.9–98.1%
Milano et al, 2000, Italy	62 patients undergoing mitral valve repair for degenerative MR Local posterior annuloplasty (group I, n = 10) Rigid Carpentier ring (group 2, n = 20) Duran ring (group 3, n = 17) and Posterior annular plication with autologous pericardium (group 4, n = 15)	Retrospective study (level 2b)	Early death	Nil	Retrospective study Small sample size Non-randomised
			Late death	Nil
			Reoperation	One patient in group 2 required reoperation 14 months after repair
			Residual MR	In patients of groups 2, 3 and 4, residual mitral incompetence at follow-up was not significantly different from discharge Group 1 A higher degree of residual mitral regurgitation was present at discharge (0.9±0.6) with a trend to progress at follow-up (1.6±0.5) Group 2 0.8±0.9 Group 3 0.8±0.7 Group 4 0.2±0.6
			Improvement in NYHA class	In all groups there was a significant improvement in NYHA functional class (from 2.7±0.6 to 0.9±0.5, P<0.001)
			LVESV	In all groups there was a significant reduction of LVESV (64±23 ml to 52±22 ml, P<0.001)
			LVEDV	In all groups there was a significant reduction of LVEDV (154±50 ml to 105±33 ml, P<0.001)

Comment(s)

Several sophisticated echocardiographic studies have demonstrated that patients with a flexible annuloplasty ring have better LV systolic function than patients with a rigid annuloplasty ring after mitral valve reconstruction for chronic MR secondary to degenerative disease of the mitral valve [Borghetti, Dall'Agata, Yamaura 1995 and 1997, Okada, Unger-Graeber, David]. Borghetti et al. in their retrospective study of 44 patients showed that autologous pericardium seems to be superior to rigid prosthetic rings for annuloplasty in MV repair, since it provides more favourable mitral annulus dynamics and preserves LV function during stress conditions.

Dall'Agata et al. in a small study of 19 patients showed that the Cosgrove-Edwards ring (n=15) maintains its flexibility early after implantation and demonstrates significant systolic–diastolic changes in the mitral orifice area during the cardiac cycle compared to Carpentier rigid ring (n=4). Similar findings have been reported by other authors [Yamaura 1995 and 1997, Okada, Unger-Graeber, David].

Interestingly, clinical studies [Chung, Chang, Shahin, Bevilacqua, Milano] comparing outcomes of patients who underwent mitral valvuloplasty for degenerative MR with either a semi-rigid/rigid ring or flexible ring have shown comparable outcomes contrary to the findings of the echocardiographic studies.

Chung et al. in a recently published study compared the long-term clinical and echocardiographic outcomes of 294 patients who underwent mitral valvuloplasty for degenerative mitral regurgitation (MR) with either a Carpentier-Edwards (semi-rigid) ring (n=153) or a Duran (flexible) ring (n=141) between 1994 and 2004. Their results showed comparable long-term outcomes in terms of LV function, MR recurrence, survival and reoperation for the two groups with a greater tendency towards mitral stenosis development with the Duran ring, this being most likely due to late pannus formation.

Chang et al. in their RCT enrolling 356 patients (Carpentier ring group, n=186; Duran ring group, n=170), with similar demographics, showed similar long-term outcomes as well as left ventricular systolic function measured with echocardiography for the two groups at a mean follow-up of 46.6 months. The 8-year freedom from recurrence of significant MR was 62.6±19.0% in the Carpentier ring group and 55.5±14.1% in the Duran ring group (P=0.172).

Shahin et al. in their RCT comparing 96 patients randomised for either a Carpentier-Edwards rigid Classic (n=53) or a semi-flexible Physio (n=43) ring reported no differences in morbidity, valve function, and left ventricular function at a mean follow-up of 5.1 years.

Bevilacqua et al. in a retrospective study of 133 patients, of whom 77 patients (57.9%) received a Carpentier-Edwards ring and 56 received (42.1%) an autologous pericardium ring, showed that 5-year freedom from reoperation and recurrence of mitral regurgitation 3+/4+ was significantly higher in the prosthetic ring group (90.1% – CL90%: 81.9–98.3%) compared with the pericardial ring group (62.6% – CL90%: 43.1–82.1%; P=0.027). The results of this study contradicted the results of an earlier small retrospective study by Milano et al. which compared four different annuloplasty techniques in 62 patients: local posterior annuloplasty (group 1, n=10), rigid Carpentier ring (group 2, n=20), Duran ring (group 3, n=17), and posterior annular plication with autologous pericardium (group 4, n=15). Mean follow-up in the entire patient series was 31±12 months. One patient in group two required reoperation 14 months after MV repair. In all groups there was a significant improvement in NYHA functional class (from 2.7±0.6 to 0.9±0.5, P<0.001), with a reduction of left ventricular end-diastolic and end-systolic volumes (154±50 ml to 105±33 ml, P<0.001; and 64±23 ml to 52±22 ml, P<0.001). In patients of groups 2, 3 and 4, residual mitral incompetence at follow-up (0.8±0.9 in group 2, 0.8±0.7 in group 3, and 0.2±0.6 in group 4) was not significantly different from discharge. However, in group 1, a higher degree of residual mitral regurgitation was present at discharge (0.9±0.6) with a trend to progress at follow-up (1.6±0.5). The results of this study prompted the authors to conclude that autologous pericardium appears to be an excellent annuloplasty material.

Editor Comment

MASE, mitral annulus systolic excursion; TMFV, mean and peak trans-mitral flow velocities; RCT, randomised controlled trial; MR, mitral regurgitation; LV, left ventricle; EF, ejection fraction; LVESD, left ventricular end-systolic dimension; LVEDD, left ventricular end-diastolic dimension; LAD, left atrial dimension; MS, mitral stenosis; MPG, mean transmitral pressure gradient; CE, Carpentier-Edwards; NYHA, New York Heart Association; CHF, congestive heart failure; AMI, acute myocardial infarction; LVESV, Left ventricle end-systolic volume; LVEDV, Left ventricle end-diastolic volume; SAM, systolic anterior motion.

Clinical Bottom Line

Current best available evidence suggests that in patients with a flexible annuloplasty ring compared to patients with a semi-rigid/rigid annuloplasty ring the improvement in LV systolic function reported by sophisticated echocardiographic studies does not translate into better clinical outcomes as clinical studies, including two RCTs, report comparable outcomes for patients with mitral regurgitation secondary to degenerative mitral valve disease requiring mitral valve repair with an annuloplasty ring.

References

1. Borghetti V, Campana M, Scotti C et al. Biological versus prosthetic ring in mitral-valve repair: enhancement of mitral annulus dynamics and left-ventricular function with pericardial annuloplasty at long-term. Eur J Cardiothorac Surg 2000;17:431–439.
2. Dall'Agata A, Taams MA, Fioretti PM et al. Cosgrove-Edwards mitral ring dynamics measured with transesophageal three-dimensional echocardiography. Ann Thorac Surg 1998;65:485–490.
3. Yamaura Y, Yoshida K, Hozumi T et al. Three-dimensional echocardiographic evaluation of configuration and dynamics of the mitral annulus in patients fitted with an annuloplasty ring. J Heart Valve Dis 1997;6:43–47.
4. Okada Y, Shomura T, Yamaura Y et al. Comparison of the Carpentier and Duran prosthetic rings used in mitral reconstruction. Ann Thorac Surg 1995;59:658–662.
5. Yamaura Y, Yoshikawa J, Yoshida K et al. Three-dimensional analysis of configuration and dynamics in patients with an annuloplasty ring by multiplane transesophageal echocardiography: comparison between flexible and rigid annuloplasty rings. J Heart Valve Dis 1995;4:618–622.
6. Unger-Graeber B, Lee RT, Sutton MS et al. Doppler echocardiographic comparison of the Carpentier and Duran anuloplasty rings versus no ring after mitral valve repair for mitral regurgitation. Am J Cardiol 1991;67:517–519.
7. David TE, Komeda M, Pollick C et al. Mitral valve annuloplasty: the effect of the type on left ventricular function. Ann Thorac Surg 1989;47:524–527.
8. Chung CH, Kim JB, Choo SJ, et al. Long-term outcomes after mitral ring annuloplasty for degenerative mitral regurgitation: Duran ring versus Carpentier-Edwards ring. J Heart Valve Dis 2007;16:536–544.
9. Chang BC, Youn YN, Ha JW et al. Long-term clinical results of mitral valvuloplasty using flexible and rigid rings: a prospective and randomized study. J Thorac Cardiovasc Surg 2007;133:995–1003.
10. Shahin GM, van der Heijden GJ, Bots ML et al. The Carpentier-Edwards Classic and Physio mitral annuloplasty rings: a randomized trial. Heart Surg Forum 2005;8:E389–394.
11. Bevilacqua S, Cerillo AG, Gianetti J et al. Mitral valve repair for degenerative disease: is pericardial posterior annuloplasty a durable option. Eur J Cardiothorac Surg 2003;23:552–559.
12. Milano A, Codecasa R, De Carlo M et al. Mitral valve annuloplasty for degenerative disease: assessment of four different techniques. J Heart Valve Dis 2000;9:321–326.