PREVALENCE EVALUATION AND MANAGEMENT MITRAL RESTENOSIS PREVALENCE EVALUATION AND MANAGEMENT

DEFINITION WHAT CONSTITUTES A SUCCESSFUL PERCUTANEOUS MITRAL BALOON VALVOTOMY? Is defined as a split of one or more commissures with Post PMV valve area > 1.5 cm2 or a doubling of initial valve area and MR <2/4 Post PMV restenosis is defined as a valve area of <1.5 cm2 and a >50% loss of initial gain in valve area.

Restenosis is an ambiguous term that includes a mixture of poor result, inaccuracies in MVA determination, very early (within days) area loss, true restenosis, and disease progression. Its definition can be made on a clinical basis or in terms of mitral area, absolute area loss, % of area loss, or loss of gain. When restenosis is defined as a 50% loss of area gain, patients with a poor initial result meet restenosis criteria with only a mild area loss.. On the other hand, very early restenosis (within weeks), caused by a mixture of annular and/or valvular recoil and methodological aspects of MVA calculation, should be differentiate from late, true restenosis.

With all these confounding factors, it is not surprising that restenosis rate after PMV has ranged from 4 to 39% within 6 years of follow up and progressive decrease of MVA over time has been well documented.The restenosis definition in itself may play a major role in restenosis rate

Prevalence of mitral restenosis following PMV STUDY GROUP SAMPLE SIZE AVERAGE AGE FOLLOW UP INCIDENCE 1.BEN-FARHAT et al 654 33 +/- 13 5 yrs-12% 7 yrs-20% 10 yrs-34% 2.Fawzy et all 547 31 +/- 13 2d echo and doppler 9 ± 5.2 years-31% 3. Wang et al 206 52+/-13 a 6 yrs-40% 4.Desideri et al 57 19 +/- 6 months-21% 5.Lau KW et al 68 36-63 months-15% 6.Hernandez R et all 561 53 yrs 2D echo 39 +/-23 months -10% 7 yrs-39% 7. Ribiero et all 66 31+/-12 yrs o 1 year -6%

Prevalence of mitral restenosis following CMV STUDY GROUP AGES NUMBER PREVALENCE STANLEY JOHN 6-69 3724 Ates A et al 28.8 +/- 6.1 years 36 14 Years-8.5%

INCIDENCE OF RESTENOSIS IN STANLEY JOHN STUDY FROM CMC VELLORE (1956-1980)

The incidence of mitral restenosis was low in the study The incidence of mitral restenosis was low in the study.They attributed it to the large number of young patients (25% of patients were less than 20 yrs and 40% were between 20 and 30) who had pliable valves and were excellent subjects for CMV. The study indicates that peak time for incidence of restenosis was 12 years post procedure with a gradual decrease in incidence thereafter.

Prevalence of mitral restenosis following OMC STUDY GROUP SAMPLE SIZE PH Kay P Belcher et al 1968-80 222 10 years- 16%

Farhat et al conducted a prospective, randomized trial comparing the results of the 3 procedures(BMC OMC and CMC) in 90 patients (30 patients in each group) with severe pliable MS. Cardiac catheterization was performed in all patients before and at 6 months after each procedure. All patients had clinical and echocardiographic evaluation initially and throughout the 7-year follow-up period. At 7-year follow-up, echocardiographic MVA was similar and greater after BMC and OMC (1.8±0.4 cm2) than after CMC (1.3±0.3 cm2; P<.001). Restenosis (MVA <1.5 cm2) rate was 6.6% after BMC or OMC versus 37% after CMC

PATHOLOGY (how is mitral restenosis different from mitral stenosis) Commissural fusion was rarely seen on serial echo follow up. Splits produced in commissures during initial PMV were still present with restenosis during autopsy (Tsuji T et al) End stage rheumatic valvular disease in leaflet and subvalvular fusion was main mechanism.

A study from Italy proposed 2 potential mechanisms of restenosis 1.A more common slow process due to turbulent flow induced trauma to mitral valve 2. A rapid process that relates to valvulitis consequent to subclinical occurrence of chronic rheumatic activity

EVALUATION

Parameters to be assessed by ECHO Severity of mitral stenosis Pliability---calcification valve thickening(uniform/non uniform) subvalvular pathology commissural morphology Mitral regurgitation

LA thrombus Assessment of interatrial septum Diseases of other valves Assessment of pulmonary hypertension

Wilkins score -Mitral valve score <8 are excellent candidates for BMV

Limitations of wilkin score Assessment of commissural involvement is not included Limited in ability to differentiate nodular fibrosis from calcification. Doesn’t account for uneven distribution of pathologic abnormalities. Frequent underestimation of subvalvular disease. Doesn’t use results from TEE or 3D echo

Cormier’s method

3D ECHO TEE and TTE Higher accuracy than 2D echo Detailed information of commissural fusion and subvalvular involvement MVA measurement in calcified and irregular valve MVA measurement after BMV Restenosis after commissurotomy commissural re-fusion valve rigidity with persistent commissural opening

From LA From LV

RT3DE score of MS severity

Total RT3DE score ranging from 0 to 31 points Total score of mild MV involvement was defined as <8 points Moderate MV involvement 8–13 Severe MV involvement >14

TRANSESOPHAGIAL ECHO To rule out left atrial or appendage thrombus Accurate assessment of mitral regurgitation Assess associated lesions Assess nature of inter atrial septum

Commissure score NON CALCIFIED FUSION ANTEROLATERAL COMMISSURE POSTEROMEDIAL COMMISSURE ABSENT PARTIAL 1 EXTENSIVE 2 TOTAL SCORE O TO 4

Scores for anterolateral and posteromedial commissures were combined such that each valve had an overall commissure score ranging from 0–4 A high score indicated extensively fused, non‐calcified commissures that were therefore more likely to split A low score indicated either minimal fusion or the presence of resistant commissural calcification

Cardiac catheterization

Management of mitral restenosis

Medical management Control of heart rate-beta blockers calcium channel blockers-verapamil,diltiazem Diuretics-to control pulmonary venous hypertension,right heart failure Digoxin-can be given to control rate but beta blockers are preffered can be given in atrial fibrillation,RV failure,Pulmonary hypertension Rheumatic fever prophylaxis Anticoagulation-to achieve INR 2-3

SURGICAL MANAGEMENT

Closed mitral valvotomy for mitral restenosis: Experience in 113 consecutive cases(RK Suri PGI)   113 consecutive patients with mitral restenosis. Closed transventricular revalvotomy was performed with Tubbs dilator in 105 of 113 patients. Mean age was 34.3 years, with a male to female ratio of 1:1.5. Most patients were in New York Heart Association functional classes III and IV (74.3% and 19.4%, respectively). Mean interval between first and second valvotomy was 9.4 years. )

Hospital mortality rate was 2 Hospital mortality rate was 2.8%, trivial postoperative mitral regurgitation occurred in 16.1%, and moderately severe regurgitation occurred in 1.9%. Early postoperative systemic embolism occurred in 3.8% of the cases. Moderate to excellent symptomatic improvement was noted in 89.4% of the cases and poor results were seen in 10.2%. Late follow-up of 76 patients ranged from 2 to 10 years (mean 3.8 years), with 39.4% patients in New York Heart Association class I and 50% in class II. Close mitral revalvotomy is thus an economical, simple, and safe palliative procedure that carries good long-term results. (J THORAC CARDIOVASC SURG1996;112:727-30

REDO PERCUTANEOUS BALLOON MITRAL VALVOTOMY Favorable valve morphology. No left atrial thrombus. Absence of commissural calcification. No or mild Mitral regurgitation. High risk candidates for surgery even when valve morphology is not ideal like elderly frail patients,mitral stenosis complicated by pulmonary renal or neoplastic diseases,pregnant women,or women in child bearing age group in whom mitral valve replacement is not desired.

Percutaneous balloon mitral valvotomy in mitral restenosis vs de novo MS (Gupta et al KEM) STUDY 614 consecutive patients undergoing balloon valvotomy and identified 84 patients (13.7%) with mitral restenosis following prior surgical valvotomy (Group I). The remaining 530 patients (86.3%) had not undergone previous surgery (Group II). The incidence of atrial fibrillation (19% vs 5.6%), mitral valve calcification (50% vs 30.6%) and total echo score > 8 (54.8% vs 24.15%) was significantly higher in Group I. Both groups were comparable as regards their functional class, technique of valvotomy, mitral valve area (0.87 +/- 0.18 vs 0.87 +/- 0.15 cm2, P = ns), mean transmitral gradient (19.63 +/- 6.01 vs 19.21 +/- 5.67 mmHg, P = ns), and mean pulmonary artery pressure (42.2 +/- 19.0 vs 40.8 +/- 14.4 mmHg, P = ns).

RESULTS: After percutaneous balloon mitral valvotomy, the final mitral valve area (1.67 +/- 0.28 vs 1.69 +/- 0.29 cm2, P = ns), mean transmitral-mitral gradient (6.12 +/- 3.68 vs 5.02 +/- 3.21 mmHg, P = ns) and mean pulmonary artery pressure (31.0 +/- 15.2 vs 28.5 +/- 11.1 mmHg, P = ns) were comparable. The success rate (93.0% vs 95.3%, P = ns) were similar in both groups. Significant mitral regurgitation was seen in four (4.8%) patients in Group I and 22 (4.1%) patients in Group II (P = ns). There were two deaths (2.4%) in Group I and five (0.9%) in Group II (P = ns). The clinical and echo Doppler follow-up (8-40 months) studies showed that both groups were of similar NYHA class, and had similar mitral valve area (1.65 +/- 0.21 vs 1.66 +/- 0.3 cm2) and transmitral gradients (7.1 +/- 3.8 vs 5.9 +/- 3.5 mmHg).

Percutaneous mitral commissurotomy for restenosis after surgical commissurotomy(Bernard Iung et al) 232 patients who had undergone percutaneous mitral commissurotomy a mean of 16 ± 8 years after surgical commissurotomy. Mean age was 47 ± 14 years. All patients had restenosis with bilateral commissural fusion as assessed by echocardiography 191 patients (82%) had good immediate results (valve area ≥1.5 cm2 without regurgitation >2/4). Predictors of poor immediate results in multivariate analysis were older age (p < 0.001), lower initial valve area (p = 0.01) and the use of the double-balloon technique (p = 0.015). In the 175 patients who underwent follow-up, 8-year survival without operation and in New York Heart Association class I or II was 48 ± 5%, and 58 ± 6% after good immediate results.

Immediate and long-term results of mitral balloon valvotomy for restenosis following previous surgical or balloon mitral commissurotomy(fawzy et al 2005) PMV for de novo MS PMV for restenosis Sample size 524  56 Mean age 28 +/- 8.8 years  31 +/- 11 years Successful BMV(immediate)  504 of 524 patients (96%)  Fifty-two of 56 patients (93%)  Freedom from restenosis at 10 years 69 +/- 3% 58 +/- 7% Ten-year event-free survival rate  80 +/- 3% 54 +/- 7%

Percutaneous valvuloplasty for mitral valve restenosis: postballoon valvotomy patients fare better than postsurgical closed valvotomy patients. (K Nair et al)SCT POST BMV GROUP POST CMV GROUP NUMBER OF PATIENTS 28 64 SUCCESSFUL PROCEDURE 57.1% 59.3%  Need for mitral valve replacement (MVR), need for re-repeat BMV for mitral restenosis or death   7.1% 31.2% Event-free survival 92.8% 69%

Repeat surgical commisurotomy vs PMV for restenosis There are no head to head comparisons of repeat surgical commisurotomy vs PMV for restenosis. Repeat surgical commissurotomy has an operative mortality of 2.5-10%,risk of systemic embolism ranging from 1-4% and operative success and improvement in functional class 50-85%.

Comparison of long-term outcome after mitral valve replacement or repeated balloon mitral valvotomy in patients with restenosis after previous balloon valvotomy.(Kim JB et al Am JC 07) Thirty-two patients underwent repeated PMV, and 59 patients underwent MVR for symptomatic MS. Mean follow-up was 85 +/- 43 months with a maximum follow-up of 15 years. Patients with MVR have more unfavorable clinical characteristics, including a higher incidence of atrial fibrillation and severe mitral regurgitation. .

Event-free survival was similar between the 2 groups up to 40 months after the procedure; 3-year event-free survival rates were 96.6% for MVR patients and 90.0% for repeated PMV patients (p = 0.215). However, after 40 months, the outcome was more favorable for MVR. Comparing MVR versus PMV, 6- year event-free survival rates were 93.0% versus 75.9% (p = 0.036), and 9- year event-free survival rates were 90.4% versus 36.0% (p <0.001). In conclusion, the long-term outcome of patients with symptomatic MS after previous PMV was more favorable after MVR than after repeated PMV. These data suggest that MVR may be the preferred mode of therapy in patients with unfavorable valve morphologic characteristics and no co- morbid disease.

Repeat BMV is the treatment of choice in young patients with favorable Wilkins score,especially those with minimal lesions in the subvalvular apparatus in whom the main mechanism of restenosis iss likely bilateral commissural fusion. Those with high echocardiographic scores >8 are less likely to have long term benefit and mitral valve replacement should be considered. Repeat BMV may also be considered in patients with poor Wilkins score if they cannot undergo surgery due to comorbities.

Success rate of BMV for mitral restenosis varies from 50-90% compared to denovo MS where the success rate is between 85-95%.The lower success rate of patients is attributed to the higher age and higher Wilkins score during the second procedure. Mitral restenosis is generally non commissural.The subvalvular site is the major site of stenosis and multiple slow dilations may be needed at the subvalvular level increasing the risk of mitral regurgitation due tto subvalvular damage leading to mitral valve replacement.So it is better to accept a lesser result with no significant regurgitation in a bad valve rather than risk significant regurgitation in an attempt to increase valve area

Predictors of success following redo BMV WILKINS SCORE-success for BMV was higher (70.5%)if score was <8 compared to 43.5 % if >8 (Nair et al) Younger age-strong predictor of good immediate outcome (rifae et sl) Atrial fibrillation- higher risk of poor outcome. (Iung et al) Previous BMV better outcome whe compared to previous CMV (Nair et al)

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