Redo Percutaneous Mitral Valvuloplasty (Redo PMV) in Patients With Recurrent Mitral Valve Stenosis: Immediate and Early Outcomes

Document Type: Original article

Authors

1 Research Center of Endovascular Intervention, Department of Interventional Cardiology, Imam Khomeini Hospital complex, Tehran University of Medical Sciences, Tehran, Iran

2 Department of Interventional Cardiology, Imam Khomeini Hospital complex, Tehran University of Medical Sciences, Tehran, Iran

3 University of Toronto, Mount Sinai Hospital,700 University Avenue , 3rd floor, Room 3-522,Toronto, ON, M5G Canada

4 University of Arizona,Tucson, Arizona, USA

5 Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran

Abstract

Background: Symptomatic recurrent mitral valve stenosis develops in some patients after Percutaneous Mitral Valvuloplasty (PMV). This study assessed the immediate and early outcomes of redo PMV in patients with recurrent mitral valve stenosis after prior PMV.
Methods: Fifty-four patients (40 women and 14 men, mean age of 38±8.2 years) underwent a redo (second) PMV for symptomatic restenosis of mitral valve [with Mitral Valve Area (MVA) < 1.5 cm2]. Redo PMV was performed at 5.8±1.2 years after the initial PMV.
Results: In this study, 48 hours after the procedure, there was a substantial increase in MVA by 2-dimensional Echocardiography (GE, Vivid 7) from 1.0±0.2 to 2.2±0.4 cm2 (p<0.001) and a decrease in mean left atrial pressure from 27 ± 5 to 15 ± 4 mmHg (p<0.001) and in mean transmitral valve gradient from 15±4 to 2±1 mmHg (p Conclusion: Redo PMV can be performed successfully in patients with recurrent mitral valve stenosis following previous percutaneous valvuloplasty.

Keywords


Abstract
Background: Symptomatic recurrent mitral valve stenosis develops in some patients after Percutaneous Mitral Valvuloplasty (PMV). This study assessed the immediate and early outcomes of redo PMV in patients with recurrent mitral valve stenosis after prior PMV.
Methods: Fifty-four patients (40 women and 14 men, mean age of 38±8.2 years) underwent a redo (second) PMV for symptomatic restenosis of mitral valve [with Mitral Valve Area (MVA) < 1.5 cm2]. Redo PMV was performed at 5.8±1.2 years after the initial PMV.
Results: In this study, 48 hours after the procedure, there was a substantial increase in MVA by 2-dimensional Echocardiography (GE, Vivid 7) from 1.0±0.2 to 2.2±0.4 cm2 (p<0.001) and a decrease in mean left atrial pressure from 27 ± 5 to 15 ± 4 mmHg (p<0.001) and in mean transmitral valve gradient from 15±4 to 2±1 mmHg (p Conclusion: Redo PMV can be performed successfully in patients with recurrent mitral valve stenosis following previous percutaneous valvuloplasty.
Keywords: Echocardiography, Heart valve diseases, Mitral valve, Mitral valve stenosis
Introduction
Treatment of rheumatic mitral valve stenosis has dramatically changed during the last few decades. Before 1984, when Inoue et al first described theclinical
application of Percutaneous Mitral Valvuloplasty (PMV), surgical mitral commissurotomy was the preferred option for patients who had severe Mitral Stenosis (MS) (1).
Different terminologies have been used for this procedure including Percutaneous Mitral Balloon Valvuloplasty (PMBV) (2), Percutaneous Mitral Commissurotomy (PMC), Balloon Mitral Valvotomy (BMV) (3), and newly Percutaneous Mitral Valvuloplasty (PMV) (4). PMV is an alternative to surgical mitral commissurotomy for patients with mitral stenosis. After the first PMV, the rate of recurrent heart failure or recurrence of symptoms due to recurrent mitral valve stenosis reached to 39% (5-7). Although some of the patients with recurrent mitral valve stenosis currently undergo
Mitral Valve Replacement (MVR), it is not known whether these patients may benefit from a repeat PMV or not.
Only a few studies have evaluated results of redo PMV; however, they have showed promising results in specific patients with suitable valve morphology (7-9).
The aim of this study was to evaluate early results of a second PMV (redo PMV) in symptomatic patients with recurrent mitral valve stenosis (history of previous PMV).

Materials and Methods
Patient selection and echocardiographic evaluation
Fifty four patients (40 women and 14 men, mean age of 38±8.2 years) with symptomatic severe MS (10) and Mitral Valve Area (MVA) < 1.5 cm2 underwent redo PMV at our center (with loss of > 50% of the first gain of MVA after successful initial PMV).
Redo PMV was performed at 5.8±1.2 years after the initial successful PMV.
Baseline clinical and echocardiographic characteristics of the study population are summarized in table 1. All patients presented with Dyspnea on Exertion (DOE) New York Heart Association (NYHA) class I (Table 1).

Table 1. Baseline characteristics of the patients who underwent redo PMV

Variables

Value

Age (years)

38± 8.2

Gender

Male

14 (26%)

Female

40 (74%)

NYHA class

I

0 (0%)

II

10 (18.52%)

III

34 (62.96%)

VI

10 (18.52%)

Rhythm

 

Sinus

19 (35.1%)

Atrial fibrillation

35 (64.9%)

Severe left ventricular dysfunction

4 (7.4%)

Severe chronic lung disease

8 (14.8%)

Hypertension

11 (20.3%)

Diabetes mellitus

13 (24% )

Previous cerebrovascular accident

4 (7.4%)

Chronic renal failure

2 (3.7%)

Echocardiographic score >8

30(55.5%)

NYHA : New York Heart Association Functional Class

 

This study involved only patients with pure, isolated, and rheumatic mitral valve stenosis.
Two-dimensional transthoracic echocardiography (GE, Vivid 7) was performed 1 week before and 2 days after the redo PMV by the same operator. Transesophageal echocardiography (by the same operator) was also performed before each procedure to rule out any left atrial thrombus. The patients were considered for redo PMV who had favorable echocardiographic criteria for this procedure.
The echocardiographic score described by Wilkins et al (11) was used to assess baseline anatomic features of the mitral valve and a score from 1 (normal) to 4 (severely deformed) was assigned to valvular mobility, thickening, calcifications, and subvalvular thickening.
Exclusion criteria were patients with unsuitable mitral valve morphology (described as a Massachusetts General Hospital [MGH] score ≥ 12), who had history of surgical mitral commissurotomy, the patients with more than moderate mitral, aortic or tricuspid regurgitation or other concomitant valve involvement that needed surgery, patients waiting for coronary artery bypass surgery and finally patients with significant comorbidity (malignancy) which limited their life expectancy.

Percutaneous mitral valvuloplasty and hemodynamic study
Transesophageal echocardiography was done before the procedure for detection of clot in the left atrium or left atrial appendage. The redo PMV procedure was performed by the stepwise Inoue technique in all of patients. For selection of the appropriate balloon size, patient’s height was used as the measure. Hence, the famous formula of height [cm]/10+10 was applied for obtaining the reference size (12,13).
The right femoral vein and right femoral artery access was provided. Two pigtail catheters were inserted in the Right Atrium (RA) and Left Ventricle (LV). LV pressures were recorded, ventriculography was done for determining angiographic severity of mitral regurgitation, and then pigtail catheter was pulled back into ascending aorta as a marker. Dye injection was done in RA and Left Atrium (LA) was appeared in levophase.
For finding a precise transseptal puncture site, first, two imaginary reference lines of (1) the horizontal “M-” line and (2) the vertical “midline” were defined .Then, septal puncture was done at the intersecting point of the horizontal “M-line” and the vertical “midline” (14-16).
Once interatrial septum was punctured, the needle entry into the left atrium was confirmed, first, by contrast injection then by hemodynamics study (Pressure recording).
Then, catheter was advanced forward 2 cm into the left atrium, while the needle was withdrawn. Heparin 100 U/kg was administered intravenously. The coiled-tip guidewire was inserted into the left atrium, and the balloon was pushed slowly into left atrium over the coiled-tip guide wire to form a large loop with the tip pointing in a 6-7 o’clock direction, medial to the orifice of mitral valve. For crossing mitral valve, the stylet was inserted to the catheter tip and the partially inflated distal balloon was directed toward the mitral orifice, by a counterclockwise rotation.
With the balloon in the left ventricle, the distal portion of the balloon was inflated with a large syringe attached to the proximal portion of the catheter outside the femoral vein, and the balloon was withdrawn against the mitral valve. Then, the remainder of the balloon was inflated, causing enlargement of the mitral orifice.
Complete cardiac catheterization was performed in all cases before and immediately after the procedure. Complete hemodynamic measurement of the right and left heart chambers, including simultaneous left atrial and left ventricular pressure measurements (for invasive study of the mean diastolic pressure gradient across the mitral valve) was performed immediately before and after the valvuloplasty.
Cine left ventriculography was performed before and after the redo PMV to assess the presence and severity of angiographic mitral regurgitation.
Evaluation of patients from the procedural aspect was done by transthoracic echocardiography immediately at the end of procedure as well as 48 hours after the procedure. Immediate echocardiography was done for evaluation of acute or critical complications, but detailed echocardiography and analysis of data were done on the basis of echocardiography of 48 hours later.
MVA was determined through planimetry of the mitral orifice in a 2-dimensional short-axis view early in the diastole. Transmitral pressure half-time method was used in patients who had less than or equal to grade 2 Mitral Regurgitation (MR). MR was graded by color Doppler imaging on a scale of 1+ to 4+, according to the jet extension in the left atrium and also detailed echocardiography principles (10) .Short-term clinical follow-up data were available in all patients for whom redo PMV was performed.

Table 2. Echocardiographic results of the redo PMV

Variables

Before redo PMV

Post redo PMV

p value

Doppler measurements:

Final MVA (cm2)

1.0 ±  0.2

2.2 ±  0.4

<0.001

Gain of MVA (cm2)

 

1.2±  0.2

 

Mean MPG (mmHg)

15 ± 4

2 ± 1

<0.001

Invasive measurements:

Mean left atrial pressure (mmHg)

27 ± 5

15 ± 4

<0.001

Mean MPG (mmHg)

16 ±  4

4 ± 1

<0.001

Mitral regurgitation

0

30(55.6%)

22(40.7%)

NS *

1

 22(40.7%)

26(48.2%)

 

2

2(3.7%)

5(9.2%)

 

3

0(0%)

0(0%)

 

4

0(0%)

1(1.9%)

 

 

All variables are presented as mean ± SD

* Non-significant

¶ Mean mitral valve pressure gradient

Definitions

Criteria for procedural success were considered as an increase of ≥ 50% in MVA (Obtained MVA ≥ 1.5 cm2) in absence of major complications. Major complications were described as cardiac tamponade, periprocedural death, more than grade 2/4 MR, and cerebrovascular stroke (7).

Statistical analysis
Quantitative variables were expressed as mean ± standard deviation. Procedural success was considered as the immediate and early results of redo PMV in terms of a 50% or more increase in mitral valve area and a final mitral valve area ≥ 1.5 cm2, with no regurgitation >2/4 and without major complications (8).
Continuous data (e.g. MVA) were compared with use of the student 2-tailed t-test and discrete data with chi-squared test. Moreover, p

Results
In our study group, mean age of subjects was 38±8.2 years with 40 women and 14 men. Thirty five patients (64.9%) had Atrial Fibrillation (AF) rhythm. Percutaneous mitral valvuloplasty (redo procedure) was successfully performed in all patients except one. There was no in hospital death. None of the patients developed cardiac tamponade. One patient underwent urgent mitral valve replacement immediate after PMV procedure, because of the mitral valve rupture.
Except the above case, none of the patients developed severe mitral regurgitation (Grade 3, 4) after redo PMV. There were no severe adverse events such as cerebral embolism and stroke. After the procedure, there was a substantial increment in mean MVA by 2-dimensional echocardiography (planimetry method) from 1.0 ± 0.2 to 2.2 ± 0.4 cm2 (p<0.001) and a decrease in mean left atrial pressure from 27 ± 5 to 15 ± 4 mmHg (p<0.001) and in the mean mitral valve pressure gradient (MPG) from 15±4 to 2±1 mmHg (p<0.001). Mean pulmonary artery pressure (By invasive estimation) did not change significantly with redo PMV [38 mmHg before procedure and 32 mmHg after it (p>0.05)]. On the basis of accepted definition, procedural success was obtained in 53 patients (98.15%).
The degree of mitral regurgitation by left ventriculography immediately after redo PMV did not show significant difference with degree of mitral regurgitation before procedure (Table 2).
Good immediate results defined as post-PMV mitral valve area ≥1.5 cm2, pulmonary /systemic flow ratio ≤1.5:1 and <2/4 increase in mitral regurgitation were achieved in 53 patients (98.15%). In hospital, clinical course of these 53 patients was excellent (without any in hospital morbidity or complications). The combined events in these 54 patients were no death, but one MVR.

Discussion
In this cohort study, redo PMV for patients with mitral restenosis after favorable initial PMV provided good results. It was demonstrated that redo PMV can be a safe and satisfactory approach in selected cases with immediate procedural success of 98%, optimal final MVA and low complication rate.

Factors involved in recurrent mitral valve stenosis
Ben-Farhat showed that age, cardiac rhythm, echocardiographic score, and MVA are preprocedural predictors of recurrence. The postprocedural predictors were MVA, mitral valve gradient, mean left atrial pressure and systolic pulmonary artery pressure. Multivariate Cox analysis identified the echocardiographic score, MVA before and after PMV, and the mitral valve gradient after PMV as predictors of recurrence (17). Iung et al have reported that long term recurrent mitral valve stenosis occurred in 97% of patients with poor functional class (New York Heart Association functional class III or IV symptoms) after PMV (18).

Treatment approaches for recurrent mitral stenosis after first PMV
PMV is established as a safe and effective technique to relieve rheumatic tight mitral stenosis (19-22). Recurrent mitral valve stenosis is a frequent cause of functional deterioration after an initially successful surgical or balloon commissurotomy. The incidence of restenosis varies widely among centers and techniques. Recurrent symptoms after successful initial PMV have been indicated in 7-21% of patients; however, it is reported to reach 40% during 7 years of follow-up (7,23-25) . In earlier studies, recurrent mitral valve stenosis was defined as a decrease of 50% of the initial gain in MVA .For other investigators, MVA For many years, Mitral Valve Replacement (MVR) has been the main part of invasive therapy in patients with recurrent MS due to prominent valve deformity (7,30). However, owing to high surgical risk besides mortality and morbidity of MVR in short and long term, this way of treatment is significantly replaced with other non-surgical methods, including interventional methods like redo PMV (9). In recent years, redo PMV has been regarded as a remarkable treatment strategy and revolutionized in patients with recurrent MS particularly in those with favorable valve anatomy (9,31,32).

Immediate outcome after redo PMV
Good immediate procedural success rate of 98.15% was achieved in this study. In a study by Pathan et al, an immediate procedural success was obtained in 75% of cases (33). A study by Iung et al showed good immediate results in 48 patients (91%) (9). Higher success rate in our cases could be due to favorable patient characteristics like lower age range (38±8.2 years).Young age has been shown as a strong predictor of favorable immediate outcome of PMV (7). In the published study by Bouleti et al, the favorable outcome of repeat PMC was particularly demonstrated in patients who were younger than 50 years (34).
The safety of redo PMV (Repeat PMC) has been shown in some studies (34). In our study, urgent surgery (MVR) was needed just in one patient due to mitral valve rupture. Except one case, fortunately, no iatrogenic severe mitral regurgitation was observed after the procedure (redo PMV).
In study by Rifaie et al (7), incidence of severe MR after redo PMV was 5 %. Similar to a study by Chmielak et al (31), no adverse events such as cerebral embolism and stroke were observed comparing with 3.3% rate in another comprehensive study (7).

Long-term outcome of redo PMV based on previous studies
In one study, long term follow up showed that in patients with Wilkins score <7, event-free survival rates were significantly better than those who had higher echo score (echo score ≥ 7).They also showed that long-term survival at 8 years in patients with good immediate results was much better than cases without adequate immediate results (31). A recent report demonstrated that ,in group of redo PMV (re-PBMV), ten-year survival rate was significantly higher than surgery group (MVR) (35).
Long-term results of redo PMV were satisfactory according to another study. It was demonstrated that gain of >1.8 cm2 in mitral valve area was effectively correlated with event-free survival rates and also restenosis at five-year follow-up (36).

Clinical implications
Limitations
This was a cohort study of selected patients with relatively younger age. Therefore, the same results may not be obtained among older individuals with many comorbid conditions. Moreover, only early outcome after the redo PMV is reported in this study. Longer follow up is needed to evaluate long term consistency of the excellent short-term results. This study was a single center study with great experience in performing PMV. Our low rate of complications may not be achieved in centers with low-volume operators.
Conclusion
This study suggests that redo PMV in patients with a history of PMV and recurrent
symptomatic mitral valve stenosis is safe and should be the procedure of choice. Though mitral valve surgery should be the treatment of choice for patients with more extensive valvular and subvalvular deformity, redo PMV can be utilized as a good alternative in these patients with high surgical risk for mitral valve surgery.

Conflict of Interest
Authors have no conflict of interest to disclose.

1. Inoue K, Owaki T, Nakamura T, Kitamura F, Miyamoto N. Clinical application of transvenous mitral commissurotomy by a new balloon catheter. J Thorac Cardiovasc Surg 1984;87(3):394-402.
2. Palacios IF, Silva GV. Percutaneous mitral balloon valvuloplasty: surviving the test of time. Revista Brasileira de Cardiologia Invasiva 2012;20(3):237-8.
3. Carroll JD, Feldman T. Percutaneous mitral balloon valvotomy and the new demographics of mitral stenosis. JAMA 1993;270(14):1731-6.
4. Vavuranakis M, Stratos C, Kalogeras K, Aggeli C, Tsiachris D, Vaina S, et al. An alternative method of percutaneous mitral valvuloplasty. Matching electrophysiology with interventional cardiology techniques. Int J Cardiol 2015;191:294-5. https://www.ncbi.nlm.nih.gov/pubmed/25984897/
5. Palacios IF, Tuzcu ME, Weyman AE, Newell JB, Block PC. Clinical follow-up of patients undergoing percutaneous mitral balloon valvotomy. Circulation 1995;91(3):671-6.
6. Hernandez R, Banuelos C, Alfonso F, Goicolea J, Fernández-Ortiz A, Escaned J, et al. Long-term clinical and echocardiographic follow-up after percutaneous mitral valvuloplasty with the Inoue balloon. Circulation 1999;99(12):1580-6.
7. Rifaie O, Ismail M, Helmy M, El-Bialy M, Nammas W. Redo percutaneous mitral valvuloplasty for mitral restenosis: a comparison with first procedure for de novo mitral stenosis. Kardiologia Polska (Polish Heart Journal) 2011;69(2):125-31.
8. Rifaie O, Ismail M, Helmy M, El-Bialy M, Nammas W. Redo percutaneous mitral valvuloplasty for mitral restenosis: a comparison with first procedure for de novo mitral stenosis. Kardiologia polska. 2010;69(2):125-31.
9. Iung B, Garbarz E, Michaud P, Fondard O, Helou S, Kamblock J, et al. Immediate and mid-term results of repeat percutaneous mitral commissurotomy for restenosis following earlier percutaneous mitral commissurotomy. European Heart J 2000;21(20):1683-9.
10. Nishimura RA, Otto CM, Bonow RO, Carabello BA, Erwin JP, Fleisher LA, et al. 2017 AHA/ACC focused update of the 2014 AHA/ACC guideline for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J American College of Cardiology 2017.
11. Wilkins G, Weyman AE, Abascal V, Block P, Palacios I. Percutaneous balloon dilatation of the mitral valve: an analysis of echocardiographic variables related to outcome and the mechanism of dilatation. Br Heart J 1988;60(4):299-308.
12. Nobuyoshi M, Arita T, Shirai S-i, Hamasaki N, Yokoi H, Iwabuchi M, et al. Percutaneous balloon mitral valvuloplasty: a review. Circulation 2009;119(8):e211-e9.
13. Tastan A, Ozturk A, Senarslan O, Ozel E, Uyar S, Ozcan EE, et al. Comparison of two different techniques for balloon sizing in percutaneous mitral balloon valvuloplasty: which is preferable? Cardiovascular J Africa 2016;27(3):147.
14. Hung JS. Atrial septal puncture technique in percutaneous transvenous mitral commissurotomy: mitral valvuloplasty using the Inoue balloon catheter technique. Catheterization and Cardiovascular Diagnosis 1992;26(4):275-84.
15. Babaliaros VC, Green JT, Lerakis S, Lloyd M, Block PC. Emerging applications for transseptal left heart catheterization: old techniques for new procedures. J Am Coll Cardiol 2008;51(22):2116-22.
16. Naik N. How to perform transeptal puncture. Indian Heart J 2015;67(1):70-6.
17. Ben-Farhat M, Betbout F, Gamra H, Maatouk F, Ben-Hamda K, Abdellaoui M, et al. Predictors of long-term event-free survival and of freedom from restenosis after percutaneous balloon mitral commissurotomy. Am Heart J 2001;142(6):1072-9.
18. Iung B, Garbarz E, Doutrelant L, Berdah P, Michaud P, Farah B, et al. Late results of percutaneous mitral commissurotomy for calcific mitral stenosis. American J Cardio 2000;85(11):1308-14.
19. Ali L, Asghar N, Riaz R, Hussain M. Percutaneous transmitral commissurotomy (PTMC); procedural success and immediate results, a tertiary care hospital experience from develping country. Professional Medical J 2016;23(1).
20. Dean LS. Complications and mortality of percutaneous balloon mitral commissurotomy. Circulation 1992;85(6):2014-24.
21. Bouleti C, Iung B, Brochet E, Messika-Zeitoun D, Himbert D, Garbarz E, et al. The impact of the presence and extent of valve calcification on long-term results of percutaneous mitral commissurotomy. Archives of Cardiovascular Diseases Supplements 2013;5(1).
22. Esteves WAM, Lodi-Junqueira L, Soares JR, Athayde GRSA, Goebel GA, Carvalho LA, et al. Impact of percutaneous mitral valvuloplasty on left ventricular function in patients with mitral stenosis assessed by 3D echocardiography. Int J Cardiol 2017 Dec 1;248:280-5. https://www.ncbi.nlm.nih.gov/pubmed/28712559 
23. Harken DE, Black H, Taylor WJ, Thrower WB, Ellis LB. Reoperation for mitral stenosis. Circulation 1961;23(1):7-12.
24. Ellis LB, Singh JB, Morales DD, Harken DE. Fifteen-to twenty-year study of one thousand patients undergoing closed mitral valvuloplasty. Circulation 1973;48(2):357-64.
25. John S, Bashi V, Jairaj P, Muralidharan S, Ravikumar E, Rajarajeswari T, et al. Closed mitral valvotomy: early results and long-term follow-up of 3724 consecutive patients. Circulation 1983;68(5):891-6.
26. Palacios IF, Block PC, Wilkins GT, Weyman AE. Follow-up of patients undergoing percutaneous mitral balloon valvotomy. Analysis of factors determining restenosis. Circulation 1989;79(3):573-9.
27. Pan M, Medina A, de Lezo J, Hernández E, Romero M, Pavlovic D, et al. Factors determining late success after mitral balloon valvulotomy. Am J Cardiol 1993;71(13):1181-5.
28. Block PC, Palacios IF, Block EH, Tuzcu EM, Griffin B. Late (two-year) follow-up after percutaneous balloon mitral valvotomy. Am J Cardiol 1992;69(5):537-41.
29. Shavelle DM, Otto CM, Tavel ME. Recurrent mitral stenosis: Problems of management. CHEST J 2001;119(3):958-60.
30. Dean LS, Mickel M, Bonan R, Holmes DR, O’Neill WW, Palacios IF, et al. Four-year follow-up of patients undergoing percutaneous balloon mitral commissurotomy A report from then national heart, lung, and blood institute balloon valvuloplasty registry. J American College of Cardiology 1996;28(6):1452-7.
31. Chmielak Z, Klopotowski M, Kruk M, Demkow M, Konka M, Chojnowska L, et al. Repeat percutaneous mitral balloon valvuloplasty for patients with mitral valve restenosis. Catheterization and Cardiovascular Interventions 2010;76(7):986-92.
32. Gil IJN, Palacios-Rubio J, Bautista D, Salinas P, Macaya C, Fernández-Ortiz A. Long-term results of repeat percutaneous mitral valvuloplasty: Is it still a viable option? Revista Española de Cardiología 2015;68(08):728-30.
33. Pathan AZ, Mahdi NA, Leon MN, Lopez-Cuellar J, Simosa H, Block PC, et al. Is redo percutaneous mitral balloon valvuloplasty (PMV) indicated in patients with post-PMV mitral restenosis? J American College of Cardiology 1999;34(1):49-54.
34. Bouleti C, Iung B, Himbert D, Messika-Zeitoun D, Brochet E, Garbarz E, et al. Long-term impact of repeat percutaneous mitral commissurotomy on the need for surgery in mitral stenosis. Insights from a series of 912 patients with a 20-year follow-up. Archives of Cardiovascular Diseases Supplements 2012;4(1):90-1.
35. Aslanabadi N, Golmohammadi A, Sohrabi B, Kazemi B. Repeat percutaneous balloon mitral valvotomy vs mitral valve replacement in patients with restenosis after previous balloon mitral valvotomy and unfavorable valve characteristics. Clin Cardiol 2011;34(6):401-6.
36. Song JK, Song JM, Kang DH, Yun SC, Park DW, Lee SW, et al. Restenosis and adverse clinical events after successful percutaneous mitral valvuloplasty: immediate post-procedural mitral valve area as an important prognosticator. Eur Heart J 2009;30(10):1254-62.