|Year : 2008 | Volume
| Issue : 3 | Page : 109-113
Outcome of balloon mitral valvuloplasty in Oman
Kadhim Jaffer Sulaiman, Panduranga Prashanth
Department of Cardiology, Royal Hospital, Muscat, Oman
|Date of Web Publication||17-Jun-2010|
Department of Cardiology, Royal Hospital, P.O. Box 1331, Muscat-111
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: Balloon mitral valvuloplasty (BMV) has been successfully performed in patients with symptomatic mitral stenosis. In this study, we evaluate the safety, efficacy and outcome of BMV here in Oman.
Methods: The immediate and one year clinical and echocardiographic results of 89 consecutive patients (mean age 34 ± 12 years) who underwent BMV for severe mitral stenosis between January 1997 and June 2007 are reported.
Results: The procedure was considered successful in 86 (96%) patients. The hemodynamic mean diastolic gradient decreased from 15.4 ± 5.7 mmHg to 3.4 ± 2.9 mmHg (p < 0.0001). The mean left atrial pressure was reduced from 24 ± 7.1 mmHg to 11.6 ± 3.6 mmHg (p < 0.0001).The mean mitral valve area assessed by 2-D echocardiography increased from 0.9 ± 0.22 cm2 to 1.7 ± 0.26 cm2 (p < 0.0001). Three patients (3.3%) developed moderate to severe mitral regurgitation. Two patients expired, one due to severe mitral regurgitation and another due to sepsis unrelated to the procedure. The one year follow up mean mitral valve area was 1.6 ± 0.24 cm2, restenosis rate was 23%; and 90% of patients were in class I - II.
Conclusion: The results of this study show that BMV is a safe and effective procedure for symptomatic mitral stenosis in a low volume center with lower complication rates and good clinical improvement.
Keywords: Balloon mitral valvuloplasty, Mitral stenosis, Restenosis
|How to cite this article:|
Sulaiman KJ, Prashanth P. Outcome of balloon mitral valvuloplasty in Oman. Heart Views 2008;9:109-13
| Introduction|| |
Rheumatic mitral valve disease continues to be the most prevalent organic valve disease encountered in clinical practice in our region. Over the years, BMV has been performed with excellent short-term results in patients with symptomatic rheumatic mitral stenosis (M S). Long-term follow-up studies have shown a good outcome. We report our experience of BMV regarding its safety, efficacy and outcome in our setup in Oman.
| Methods|| |
BMV was attempted in 92 patients with symptomatic severe M S (New York Heart Association [NYHA] functional class II to IV) at our center between January 1997 and June 2007. The procedure was completed in 89 patients while in 3 patients we could not cross the mitral valve and they underwent MVR. The study population included 89 patients and their baseline characteristics are listed in [Table 1].
Patients were accepted for BMV if they fulfilled the following clinical and echocardiographic criteria: (i) presence of severe M S (absolute mitral valve area [MVA] < 1.0 cm 2 ); (ii) NYHA functional class II to IV; (iii) absence of more than mild mitral regurgitation; and (iv) absence of left atrial/left atrial appendage (LA/LAA) thrombus. Post BMV, the patients were followed up for one year with clinical and echocardiographic evaluation.
Echocardiographic evaluation: Transthoracic echocardiography (TTE) was performed using standard techniques on Hewlett-Packard Sonos 1500 and ATL HDI 5000 CV machines before and after BMV. The severity of M S and the morphology of the mitral valve were carefully assessed and transmitral gradients were measured. The MVA was derived from planimetry of the mitral valve orifice on short-axis 2-D echocardiography view in all patients. Pulmonary artery systolic pressure (PASP) was estimated using tricuspid regurgitation Doppler signal velocity. The mitral echocardiographic score (M E S) was evaluated by the method of Wilkins et al  . Transesophageal echocardiogram (TEE) was done to rule out LA/LAA clot in all patients.
Cardiac catheterization and BMV: Informed consent was obtained from all the patients. A 6 F pigtail catheter was placed at the root of the aorta. Left ventriculography was done post procedure to assess mitral regurgitation (M R) severity and was graded 0 - 4+.
BMV was performed using the conventional Inoue balloon technique  . Transseptal puncture was done using a Brockenbrough needle inserted via the right femoral vein. Heparin was administered (50 U/kg intravenously) after positioning the Inoue balloon in the left atrium. The left atrial pressure and mitral valve mean diastolic gradients were recorded before and immediately after the valve dilatation. The step-wise dilatations were done till the transmitral diastolic gradient decreased to less than 5 mmHg, unless a prominent V wave suggesting significant mitral regurgitation appeared on the hemodynamic trace. The valve area and mitral regurgitation were assessed by TTE after the procedure. The procedure was considered successful if M V A increased by > 50% as compared to the baseline and final absolute mitral valve area of > 1.5 cm 2 in the absence of significant mitral regurgitation.
Follow up: Clinical and TTE assessments were carried out at six months and one year after BMV. The primary end point of follow up was mitral restenosis, defined as loss of > 50% of the initial gain in M V A and M V A < 1.5 cm 2 . The combined secondary end point included: (1) mitral restenosis (as defined above); (2) redo BMV; (3) mitral valve replacement (MVR); (4) NYHA functional class and (5) cardiac death.
Statistical analysis: All data are expressed as mean ± SD. Comparison of data before and after BMV was performed using the t-test. A p value < 0.05 was considered significant.
| Results|| |
Baseline characteristics of 89 patients are shown in [Table 1]. The patients were aged 34 ± 12 years (range 13 - 72 years) with 72% of them females. 26% of the patients were NYHA functional class III or IV; symptomatic despite treatment with diuretic therapy, digoxin and β-blockers. Seven patients had mitral restenosis (4 of them had earlier BMV while 3 were post-open mitral valvotomy (OMV) patients). 23 patients were in atrial fibrillation with a controlled ventricular rate. Seven patients were pregnant with mean of 24 +/-4.6 weeks gestation. All pregnant patients were in NYHA class III-IV.
The TTE and catheterization data of these patients are shown in [Table 2]. The mean M E S was 6.8 ± 1.8. The hemodynamic mean diastolic gradient pre and post procedure decreased from 15.4 ± 5.7 mmHg to 3.4 ± 2.9 mmHg (p < 0.0001). The mean left atrial pressure fell from 24 ± 7.1 mmHg to 11.6 ± 3.6 mmHg (p < 0.0001). The mean mitral valve area increased from 0.9 ± 0.22 cm2 to 1.7 ± 0.26cm2 (p < 0.0001). There was also significant drop in mitral mean pressure gradient as assessed by Doppler echocardiography [Table 2].
Pregnant patients had their abdomen wrapped from just below the diaphragm down to the pubic symphysis by lead shields > 0.5 mm thickness. All pregnant patients underwent successful BMV with no complications, there were no maternal or fetal deaths and all patients delivered at full term by vaginal delivery. Mean MVA before and after BMV were similar as in other patients.
The procedure was considered successful in 86 (96%) patients. Procedural complications are shown in [Figure 1]. Post BMV MR was absent in 40 patients, recorded as grade 1 in 44 patients, grade 2 in 2 patients, grade 3 in 1 patient and grade 4 in 2 patients. Overall three patients (3.3%) developed moderate to severe mitral regurgitation. One patient had a tear of the anterior mitral leaflet, others had excessive commissural MR. Two patients developed atrial septal defect (ASD) < 1.5:1 shunt. In hospital, two patients expired (2.2%), one due to severe mitral regurgitation and another due to sepsis unrelated to the procedure.
| Follow up and Restenosis|| |
None of the patients developed any tamponade or embolic episode but two patients developed AV fistula and Psudoaneurysm respectively
87 patients were followed up for one year. The one year follow up mean mitral valve area was 1.6 ± 0.24 cm 2 . Restenosis was encountered in 20 patients (23%). Majority of the patients followed up showed an improvement in the functional class by at least 1 grade. At one year after the procedure, 55 patients were in NYHA functional class I (63%), 24 patients were in class II (27%) and 8 patients were in class III-IV (10%). Among the patients with restenosis, 8 patients with class III-IV symptoms required re-intervention (3 patients underwent MVR electively and 5 required redo-BMV), the remaining 12 patients (60%) were in NYHA class I-II and were being managed medically. There were no late deaths. There was significant reduction in pulmonary artery systolic pressure and left atrial diameter on follow up [Table 2].
| Discussion|| |
Balloon mitral valvuloplasty (BMV) as an alternative to surgery was first performed in 1982 by Kanji Inoue  in Japan. In patients with pliable valves, randomized trials  have shown that balloon mitral valvuloplasty gives an excellent result and is equal to that obtained with open or closed surgical valvotomy and benefit is sustained during long term follow up  .
This study demonstrates that BMV results in a good immediate hemodynamic and clinical improvement in the majority of patients with mitral stenosis which is similar to other studies ,, . The in-hospital complications were low.
Restenosis after BMV has been evaluated in a number of studies, with an incidence ranging from 6.5% to 40% ,,,, . Chen et al,  reported an 11 year incidence of 8%. Zaki et al  , from Egypt reported 5 year restenosis rate of 6.5%. Fawzy et al9, from Saudi Arabia have reported 5 year restenosis incidence of 14.3% and 16.1% in patients less than and more than 20 years respectively. They have again reported 31% restenosis rate in 531 patients with mean follow-up of 8.5 years  . Hernandez et al  , from Spain have reported a restenosis rate of 39% at 7 years. Wang et al  , reported 40% restenosis rate at 6 years follow up and this was predicted by higher echocardiographic score.
The restenosis incidence in our study was 23% at one year even though majority of patients were having an echocardiographic score of < 8 implying that valve morphology was not the main determinant of restenosis. It has been hypothesized that younger patients (majority in our study) may be more prone to developing restenosis because of the increased likelihood of smouldering rheumatic activity or recurrence of rheumatic fever in this age group. Majority of our patients are followed up in regional hospitals and are not on regular penicillin prophylaxis. Also there may be an ongoing immunologic response with progressive valve injury.
Restenosis and clinical outcome: Even though the restenosis rate was high in our patients, clinically they were either asymptomatic or mildly symptomatic and were managed on medical treatment. Our study demonstrated that restenosis defined by 2-D echocardiographic measurement of MVA was not related to late clinical outcome. Although MVA continues to decline during follow-up, they were relatively asymptomatic (NYHA class I-II 60%) demonstrating the disparity between the gradual process of restenosis and clinical outcome. The excellent acute procedural results of BMV may be the predominant predictors of later symptoms rather then MVA itself. This has been seen in the study done by Wang et al. Wherein, when adjusted for baseline factors and post procedural results, restenosis was no longer predictive of either major events or poorer functional status  , and they noted that the disparity between restenosis and clinical outcome suggests that the hemodynamic benefits of successful BMV persisted beyond the point of restenosis as defined by their study. A greater reduction in MVA or duration of time may be necessary before recurrent symptoms develop.
After BMV, LA stiffness has been shown to decline significantly  , and this improvement in compliance may confer symptomatic benefit despite a reduction in MVA. In support of this hemodynamic change after BMV, our analysis found that in majority of patients LA pressure after successful BMV was significantly reduced. Longer clinical follow-up of our patients who experience restenosis may reveal a stronger association between restenosis and adverse clinical events and poor functional status.
| Conclusion|| |
The results of this study show that BMV is a safe and effective procedure for symptomatic mitral stenosis in a low volume center with lower complication rates and good clinical improvement.
| References|| |
|1.||Wilkins GT, Weyman AE, Abascal VM, et al. Percutaneous mitral valvotomy: an analysis of echocardiographic variables related to outcome and mechanism of dilatation. Br Heart J 1988;60:299-308. |
|2.||Inoue K, Feldman T. Percutaneous transvenous mitral comissurotomy using the Inoue balloon catheter. Cathet Cardiovasc Diagn 1993; 28: 119-125. |
|3.||Inoue K, Owaki T, Nakamura T, et al. Clinical application of transvenous mitral commissurotomy by a new balloon catheter. J Thorac Cardiovasc Surg 1984; 87 (3): 394-402. |
|4.||Farhat MB, Ayani M, Maatouk F, et al. Percutaneous balloon versus surgical closed and open mitral commissurotomy: seven-year follow up results of a randomized trial. Circulation 1998;97:245-250. |
|5.||Chen CR, Cheng TO, Chen JY, et al. Long-term results of percutaneous balloon mitral valvuloplasty for mitral stenosis: a follow up study to 11 years in 202 patients. Cathet Cardiovasc Diagn 1998;43:132-139. |
|6.||Arora R, Nair M, Kalra GS, Nigam M, Khalilullah M. Immediate and long-term results of balloon and surgical closed mitral valvotomy: a randomized comparative study. Am Heart J 1993; 125: 1091-1094. |
|7.||Fawzy ME, Mimesh L, Sivanandam V, Lingamanaicker J, al-Amiri M, Khan B, et al. Advantage of Inoue balloon catheter in mitral balloon valvotomy: experience with 220 consecutive patients. Cathet Cardiovasc Diagn 1996; 38:9-14. |
|8.||Zaki A, Salama M, El Masry M, et al. Five-year follow-up after percutaneous balloon mitral valvuloplasty in children and adolescents. Am J Cardiol 1999;83:735-9. |
|9.||Fawzy ME, Stefadouros MA, Hegazy H, et al. Long term clinical and echocardiographic results of mitral balloon valvotomy in children and adolescents. Heart 2005; 91:743-748. |
|10.||Fawzy ME, Shoukri M, Shaer FE, et al. 18 years follow-up results of mitral balloon valvuloplasty in 531 consecutive patients and predictors of long-term outcome. Heart Views 2007; 8:130-141. |
|11.||Hernandez R, Banuelos C, Alfonso F, Goicolea J, Fernandez-Ortiz A, Escaned J, Azcona L, Almeria C, Macaya C. Long-term clinical and echocardiographic follow-up after percutaneous mitral valvuloplasty with the Inoue balloon. Circulation. 1999;99:1580-1586. |
|12.||Wang A, Krasuski RA, Warner JJ. Serial echocardiographic evaluation of restenosis after successful percutaneous mitral commissurotomy. J Am Coll Cardiol 2002;39:328-334. |
|13.||Stefanadis C, Dernellis J, Stratos C, et al. Effects of balloon mitral valvuloplasty on LA function in mitral stenosis as assessed by pressure-area relation. J Am Coll Cardiol. 1998;32:159-168. |
[Table 1], [Table 2]