Mitral Valve Replacement After Failed Mitral Ring Insertion With or Without Leaflet/Chordal Repair for Pure Mitral Regurgitation




Mitral repair operations for correction of pure mitral regurgitation (MR) are generally quite successful. Occasionally, however, the reparative procedure incompletely corrects the MR or the MR recurs. From March 1993 to January 2016, twenty nine patients had mitral valve replacement after the initial mitral repair operation, and observations in them were analyzed. All 29 patients at the repair operation had an annular ring inserted and later (<1 year in 6 and >1 year in 21) mitral valve replacement. The cause of the MR before the repair operation appears to have been prolapse in 16 patients (55%), secondary (functional) in 12 (41%) (ischemic in 5), and infective endocarditis which healed in 1 (3%). At the replacement operation the excised anterior mitral leaflet was thickened in all 29 patients. Some degree of stenosis appeared to have been present in 16 of the 29 patients before the replacement operation, although only 10 had an echocardiographic or hemodynamic recording of a transvalvular gradient; at least 11 patients had restricted motion of the posterior mitral leaflet; 10, ring dehiscence; 2, severe hemolysis; and 2, left ventricular outflow obstruction. In conclusion, there are multiple reasons for valve replacement after earlier mitral repair. Uniformly, at the time of the replacement, the mitral leaflets were thickened by fibrous tissue. Measurement of the area enclosed by the 360° rings and study of the excised leaflet suggest that the ring itself may have contributed to the leaflet scarring and development of some transmitral stenosis.


Although the results of mitral valve repair operations performed in major medical centers by very experienced cardiac surgeons are usually excellent, an unfortunate consequence of mitral valve repair with ring insertion in a few patients is inadequate elimination of the mitral regurgitation (MR) or recurrence of mitral valve dysfunction after repair with ring insertion. From 1994 through 2015 (23 years) 32 patients who earlier had had mitral valve repair with ring insertion underwent a second mitral valve operation. This report focuses on the 29 patients in whom the second operation was mitral valve replacement.


Methods


Since March 1993, all cardiac specimens excised at cardiac operations at Baylor University Medical Center (BUMC) have been described by one of us (WCR) and most have been photographed (mainly by JMK). During this 23-year period, 32 specimens of mitral annular rings with or without the anterior mitral leaflets were submitted to the surgical pathology laboratory of the Department of Pathology of BUMC. Three of them had a second mitral repair operation and they were eliminated from this study. The remaining 29 patients all had mitral valve replacement after the initial mitral repair operation and they form the basis of this study. After examining the operatively excised annular ring and anterior mitral leaflet and chordae, the clinical records were sought and examined. The interior of the complete rings was calculated by the formula for an ellipse, which is half the length of its major axis times half the length of its minor axis times pi (3.14).


The mitral valve replacement operations in the 29 patients were performed by 11 different surgeons: 10 by 1 surgeon; 6 by another; 4 by another; 2 by another, and 1 by each of 7 different surgeons. Of the mitral valve replacement surgeons, 10 had previously done the mitral valve repair operation.


The BUMC Institutional Review Board approved this study.




Results


Certain clinical and morphologic findings are tabulated for each of the 29 patients in Table 1 . The ages of the patients at the time of the mitral valve repair operation ranged from 21 to 70 years (mean 55), and at mitral valve replacement operation, from 32 to 80 years (mean 61). The interval between the 2 operations was <1 year in 8 patients and between 1 and 24 years (mean 8) in the remaining 21 patients. The cause of the MR before the valve repair operation was prolapse in 16 patients (55%); secondary (functional) in 12 (41%), 5 of whom had coronary heart disease, and infective endocarditis, which had healed, in 1 (3%). Twelve patients (41%) had coronary artery bypass grafting, 11 at the time of the mitral repair: 6 (38%) of the 16 with mitral prolapse, and 5 (42%) of the 12 with secondary (functional) MR, and also in the 1 patient with healed infective endocarditis. Five patients had aortic valve replacement (for stenosis in 4) at the time of either the repair or replacement operation.



Table 1

Certain clinical and morphologic findings in the 29 patients having mitral valve replacement after earlier mitral valve repair















































































































































































































































































































































































































































































































































































































































































































































Patient Sex Cause of
MR 		AF SH BMI
(Kg/m 2 ) 		Age (yrs)
at MV
Repair
and Ring
Insertion 		Age (yrs)
at
MVR
and Ring
Removal 		Interval
between
Operations 		MV Ring
Size (mm)
and type 		MDG
LA-LV
(mmHg) 		Explanted
Ring Area
(cm 2 ) 		Valve
Type 		CABG AVR Reason for MV Replacement Figure
Number
MS RD Leaflet
Repair
Breakdown 		H Restricted
PML 		LVOTO
1 Man Prolapse 0 0 20 49 49 16 days 33 Duran 3.9 M + 0 0 0 + 0 0 0
2 Man Prolapse + + 34 65 65 21 days 30 Edwards-physio II 5 3.9 (2.7 ∗ ) M 0 0 + 0 0 0 + + † 1
3 Man Secondary (CAD) 0 + 28 58 58 53 days – 12 3.3 M + 0 + 0 0 0 0 0 2
4 Woman Healed IE 0 + 43 68 68 63 days 28 miral flex – – B 0 0 + + 0 + 0 0
5 Man Secondary (CAD) 0 + 24 70 70 ‡ 80 days 28 Carbomedics 4 – B + 0 + + 0 0 0 0 3
6 Man Prolapse 0 0 21 43 43 91 days 33 Duran – 5.9 M 0 0 0 0 + 0 0 0 2
7 Man Prolapse 0 + 27 69 69 161 days 33 Duran – – M + 0 0 0 0 + 0 0 5
8 Man Prolapse 0 0 28 55 55 237 days – – 2.4 M 0 0 0 + + 0 0 0
9 Woman Secondary (CAD) 0 + 29 57 58 1 year – – 2.3 M + 0 0 0 + 0 0 0 6
10 Man Secondary 0 + 36 62 63 1 year 38 ATS simulus semirigid – – M 0 0 0 + + 0 + 0
11 Woman Prolapse 0 + 44 30 † 32 2 years 32 Carpentier Edwards 7 3.5 M 0 0 0 + 0 0 0 0 7
12 Woman Secondary 0 + 22 45 47 2 years 26 Cosgrove-Edwards – 0.3 M 0 + + + 0 0 + 0
13 Man Prolapse 0 + “obese” 67 69 2 years – – – B + 0 0 + 0 0 0 0
14 Woman Secondary § 0 + 29 63 66 4 years 26 Carpentier Edwards – 2.4 M 0 0 + + 0 0 + 0 8
15 Woman Prolapse + + 35 57 61 4 years 30 Carpentier Edwards 8 3.2 M 0 0 + 0 0 0 + 0 9
16 Woman Secondary + + 54 55 60 5 years 26 Carpentier Edwards 21 – (1.0 ∗ ) B 0 + + 0 0 0 + 0 10
17 Woman Secondary (CAD) + + 25 62 67 5 years – 52 0.3 B + 0 + 0 0 0 0 + † 11
18 Woman Secondary (CAD) + + 16 62 67 ∗ 5 years – – 3.1 B + 0 + 0 0 0 + 0 12
19 Woman Secondary (CAD) + + 25 66 72 6 years Duran – 0.9 M 0 0 + 0 0 0 0 0 13
20 Man Prolapse 0 0 29 66 74 8 years Carpentier Edwards – – M + 0 0 0 + 0 0 0 14
21 Man Prolapse + + 26 57 66 9 years – – 4.5 M + 0 0 0 + ‖ 0 + 0 15
22 Woman Secondary 0 + 34 29 39 10 years – 13 3.9 (1.0 ∗ ) M 0 + + + 0 0 + 0 16
23 Man Secondary 0 + 22 50 61 11 years Carpentier Edwards – 4.5 M 0 + 0 0 0 0 + 0 17
24 Man Prolapse 0 + 32 53 64 11 years 30 – 6.4 M + + 0 + + 0 + 0 18
25 Man Prolapse 0 + 24 57 68 11 years – 14 – M 0 0 + 0 + 0 0 0
26 Man Prolapse + + 21 57 70 13 years – – 6.5 B 0 0 0 0 + 0 0 0 19
27 Woman Prolapse + + 19 65 80 15 years 34 Carpentier Edwards – – B + 0 + 0 0 0 0 0
28 Woman Prolapse 0 + 27 21 43 22 years – – – M 0 0 + 0 0 0 0 0
29 Man Prolapse + + 28 47 71 24 years – 12 3.4 B 0 0 + 0 0 0 + 0 20
Totals 8 18 12 5 16 10 10 2 12 2

AF = atrial fibrillation; B = bioprosthesis; BMI = body mass index; CAD = coronary artery disease; CABG = coronary artery bypass grafting; EF = ejection fraction; H = hemolysis; IE = infective endocarditis; LA = left atrial; LV = left ventricular; M = mechanical prosthesis; MDG = mean diastolic gradient; MR = mitral regurgitation; MS = mitral stenosis; MV = mitral valve; MVR = mitral valve replacement; PML = posterior mitral leaflet; RD = ring dehisence; SH = systemic hypertension; – = not available.

∗ Area of ring calculated from echocardiogram.


† LV-aortic peak gradient at rest in case #2 was 46 mm Hg increasing to 85 mm Hg with Valsalva with severe systolic anterior motion of the anterior mitral leaflet. The LV-aortic peak systolic gradient at rest in case #17 was 41 mm Hg at rest.


‡ Left ventricular aneurysm also resected.


§ Previous acute lymphocytic leukemia treated by chemotherapy with subsequent dilated cardiomyopathy and 3+/4+ mitral regurgitation.


Aortic valve dysfunction probably secondary to systemic lupus erythmatosis.


‖ An Alfiere stitch had dehised. Of the 13 patients in whom the MR was of functional or ischemic origin or secondary to cardiomyopathy or to infective endocarditis that had healed, only a ring was inserted in 12 (92%).



Examination of the operatively excised mitral leaflet (usually only the anterior one) in all 29 patients disclosed the leaflet to the thickened, at least focally, by fibrous tissue. The areas enclosed by the 360° annular rings (calculated in 19 patients) ranged from 2.4 to 6.4 cm 2 (mean 4.4 cm 2 ) in the 9 patients in whom the MR was the result of prolapse, and from 0.3 to 4.5 cm 2 (mean 2.3 cm 2 ) in the 9 patients with secondary MR. Either echocardiographic or hemodynamic mean left atrial to left ventricular diastolic gradients were measured in 5 of the 16 patients with prolapse and they ranged from 5 to 14 mm Hg (mean 9.2), and in 5 of the 12 patients with secondary MR, from 4 to 52 mm Hg (mean 20). In 2 patients (cases #2 and #22) the mitral area just before the replacement operation was measured by echocardiogram and also by measurement of the interior of the ring after its operative excision. In both cases the mitral area determined by echocardiogram was much smaller than that determined by morphologic measurement: 2.7 and 3.9 cm 2 , respectively, in case #2, and 1.0 and 3.9 cm 2 , respectively, in case #22.


Although MR, usually severe, was present immediately before the replacement operation in all 29 patients, some degree of mitral stenosis appeared to be present in 16 of the 29 patients, although confirmed physiologically in only 10 patients. The exact site of the stenosis was not easily determined from examination of the operatively excised leaflet and ring. Some rings appeared small: at least 2 had considerable “pannus” growing into the lumen of the ring, and the leaflets in all patients were thickened at the time of the replacement operation.


Morphologic features of the operatively excised mitral leaflets and/or rings are shown in Figures 1 to 20 . A mechanical prosthesis was employed in 20 patients (69%) and a bioprosthesis in 9 patients (31%).




Figure 1


Case #2 . Shown here is the anterior mitral leaflet (A) , ventricular aspect; (B) , atrial aspect and mitral ring which had been in place for 21 days before the mitral valve replacement. The ring (30 mm Edwards Physio II) pushed the anterior mitral leaflet into the left ventricular outflow tract causing severe outflow obstruction (left ventricular to aortic peak systolic gradient at rest 46 mm Hg rising to 88 m Hg with the Valsalva maneuver) and systolic anterior motion of the anterior mitral leaflet. The ring lying on about a third of the leaflet on its atrial aspect pushed the leaflet into the outflow tract causing the obstruction, complete heart block occurred at the replacement operation necessitating pacemaker implantation.



Figure 2


Case #3 . Shown here are the mitral ring and the anterior mitral leaflet from the ventricular aspect ( A ) and from the atrial aspect ( B ). Fragments of posterior mitral leaflet, all of the anterior leaflet and the annular ring excised during mitral valve replacement 53 days after mitral valve repair procedure and coronary artery bypass grafting. The marginal portion of the anterior leaflet is thickened. After the initial repair procedure severe mitral regurgitation was present and it prompted the replacement operation. The reason for the mitral regurgitation after the repair procedure is not apparent from examination of the excised ring and leaflets, and the mechanism of the severe regurgitation was not mentioned in the operative note.



Figure 3


Case #5 . Shown here is the anterior mitral leaflet from both the ventricular aspects (A) and atrial (B) plus the semicircular mitral ring, which has been opened up considerably. The margin of the anterior leaflet on the atrial aspect is thickened and several chordae from the anterolateral half of the anterior leaflet are thickened. The cause of the recurrence of mitral regurgitation, which at least initially was due to myocardial ischemia appears to have been partial ring dehiscence. One week after the repair operation for 4+/4+ mitral regurgitation, a 4 mm Hg mean gradient was present across the mitral valve. Only a ring was used for the repair.



Figure 4


Case #6 . Shown is the ventricular aspect of anterior mitral leaflet and the 360° ring which had been in place only 3 months. The distance from mitral annular region to distal margin of anterior mitral leaflet is elongated. The mitral annulus was found by the surgeon to be quite dilated. The 360° ring is mostly covered by fibrous tissue. Severe mitral regurgitation before the mitral replacement was attributed to both inadequate repair 91 days earlier and also to the annular dilatation. The interior area is 5.9 cm 2 suggesting that the mitral annulus had been quite dilated in this patient, both before the ring was inserted and probably afterwards.



Figure 5


Case #7 . Shown is the mitral ring which was excised 161 days after having been inserted. The ring apparently caused severe hemolysis which necessitated a blood transfusion at least once a week after the ring had been inserted. The ring is a 360° one and it is covered for the most part by fibrous tissue. The severe mitral regurgitation after valve repair was due to ring dehiscence plus prolapse of the anterior mitral leaflet.



Figure 6


Case #9 . Shown here are the operatively excised mitral ring and 6 fragments of the anterior mitral leaflet. The surgeon indicated that the previous mitral repair had failed and that was the reason for the recurrence of severe mitral regurgitation. The area enclosed by the mitral ring is 2.3 cm 2 .



Figure 7


Case #11 . This patient developed mitral stenosis (mean gradient between pulmonary artery wedge position and left ventricle, 7 mm Hg) after operative repair utilizing a 360° ring. The figures show the top (A) and bottom (B) aspects of the ring which is partially covered by white fibrous tissue. The orifice barely accepts the tip of my (WCR) index finger. Thus, this is acquired stenosis after “repair” of severe pure mitral regurgitation. The interior area of the ring measures is 3.5 cm 2 .



Figure 8


Case #14 . Shown here is the operatively excised anterior mitral leaflet from its atrial aspect and the operatively excised ring. The area of the interior of the ring is 2.4 cm 2 suggesting that the ring had made the mitral orifice a bit stenotic. The mitral leaflet and several of its chords are thickened by fibrous tissue, an occurrence which could happen simply by the ring’s being in the mitral annular position for 4 years as was the case in this patient. The distance from the margin of attachment to the central free margin was only 1.2 cm, suggesting that the mitral valve leaflets were quite small and further supporting the suggestion that the valve orifice was stenotic.

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Nov 26, 2016 | Posted by in CARDIOLOGY | Comments Off on Mitral Valve Replacement After Failed Mitral Ring Insertion With or Without Leaflet/Chordal Repair for Pure Mitral Regurgitation

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