Which patients benefit from percutaneous mitral balloon valvuloplasty? Prevalvuloplasty and postvalvuloplasty variables that predict long-term outcome

Predicting success and long-term outcomes of percutaneous mitral valvuloplasty: a multifactorial score

BACKGROUND

Percutaneous mitral valvuloplasty (PMV) success depends on appropriate patient selection. A multifactorial score derived from clinical, anatomic/echocardiographic, and hemodynamic variables would predict procedural success and clinical outcome.

METHODS

Demographic data, echocardiographic parameters (including echocardiographic score), and procedure-related variables were recorded in 1085 consecutive PMVs. Long-term clinical follow-up (death, mitral valve replacement, redo PMV) was performed. Multivariate regression analysis of the first 800 procedures was performed to identify independent predictors of procedural success. Significant variables were formulated into a risk score and validated prospectively.

RESULTS

Six independent predictors of PMV success were identified: age less than 55 years, New York Heart Association classes I and II, pre-PMV mitral area of 1 cm(2) or greater, pre-PMV mitral regurgitation grade less than 2, echocardiographic score of 8 or greater, and male sex. A score was constructed from the arithmetic sum of variables present per patient. Procedural success rates increased incrementally with increasing score (0% for 0/6, 39.7% for 1/6, 54.4% for 2/6, 77.3% for 3/6, 85.7% for 4/6, 95% for 5/6, and 100% for 6/6; P < .001). In a validation cohort (n = 285 procedures), the multifactorial score remained a significant predictor of PMV success (P < .001). Comparison between the new score and the echocardiographic score confirmed that the new index was more sensitive and specific (P < .001). This new score also predicts long-term outcomes (P < .001).

CONCLUSION

Clinical, anatomic, and hemodynamic variables predict PMV success and clinical outcome and may be formulated in a scoring system that would help to identify the best candidates for PMV.

Restenosis and adverse clinical events after successful percutaneous mitral valvuloplasty: immediate post-procedural mitral valve area as an important prognosticator

AIMS

We sought to investigate the factors associated with restenosis and its potential association with late clinical deterioration after successful percutaneous mitral valvuloplasty (PMV).

METHODS AND RESULTS

We analysed echocardiographic (median 74 months) and clinical (median 109 months) follow-up data of 329 patients who achieved procedural success, defined as mitral valve area (MVA) > or =1.5 cm(2) and mitral regurgitation (MR) < or =2/4, between 1995 and 2000. Clinical events included cardiovascular death, mitral valve surgery, and repeat PMV. The 1, 3, 5, 7, and 9 year rates of restenosis-free survival were 99 +/- 1%, 97 +/- 1%, 95 +/- 1%, 86 +/- 3%, and 72 +/- 4%, respectively. The 1, 3, 5, 7, and 9 year rates of event-free survival were 99.7 +/- 0.3%, 96.4 +/- 1.0%, 94.5 +/- 1.3%, 90.8 +/- 1.6%, and 90.0 +/- 1.7%, respectively. Immediate post-PMV MVA and commissural MR or splitting, indicators of procedural adequacy, were independent predictors of both restenosis and clinical events. The best immediate post-PMV MVA cut-off value for predicting both restenosis and clinical events within 5 years after successful PMV were 1.8 cm(2) [95% confidence interval (CI) = 1.7-1.9] and 1.9 cm(2) (95% CI = 1.7-2.0), respectively. Patients with immediate post-PMV MVA <1.8 cm(2) showed significantly lower event-free survival rate than those with post-PMV MVA > or =1.8 cm(2) (P < 0.001).

CONCLUSION

Immediate post-PMV MVA> or =1.8 cm(2) was an important predictor of both restenosis- and clinical event-free survival and this value should be considered as a component of optimal result.

Evaluation of mitral stenosis in 2008

Percutaneous mitral valve commissurotomy (PMC) is the treatment of choice for patients with mitral stenosis (MS) and favorable anatomy. Evaluation of MS should answer two questions: is MS severe? And is the valve suitable for PMC? Evaluation of MS severity relies on accurate echocardiographic assessment of the mitral valve area (MVA). Several methods can be used, often in combination. The planimetry is the reference method but must be precisely performed at the tips of the leaflets in a well-oriented plane and thus requires experienced operators. New imaging technologies, such as 3D-echocardiography, MRI or computed tomography may reduce planimetry's operator dependence. The pressure half-time method (PHT) has the merit of simplicity but should be used cautiously in elderly patients or those in atrial fibrillation. It is invalid immediately after PMC but can still be used as a semi-quantitative method: a PHT less than 130 msec is associated with a good valve opening with an excellent specificity and positive predictive value whereas a PHT 130 msec does not allow any conclusion. The continuity equation, easy to perform, may be invalidated by the commonly associated aortic or mitral regurgitation or in case of atrial fibrillation. The PISA method, is reputed technically challenging and requires a direct measurement of angle between the mitral leaflets, although the use of a fixed value of 100 degrees provides an accurate MVA estimation. The main indication of transesophageal echocardiography is the exclusion of left atrial thrombus, which is a contra-indication to PMC as well as a 2/4 or greater mitral regurgitation grade. Two-dimensional-echocardiography allows detailed evaluation of valve morphology, including leaflet thickness and mobility, degree and localization of calcifications, extent of the subvalvular involvement. Unfavorable valve anatomy is associated with a lower rate of PMC success and lower event-free survival. However, given the low predictive value of all anatomic scores, the decision to perform or not the procedure should be based on a global approach taking into account not only the valve anatomy but also individual patients characteristics such as age, rhythm, NYHA class, MVA and the predicted operative mortality based on associated comorbidities.

Impact of concomitant aortic regurgitation on percutaneous mitral valvuloplasty: Immediate results, short-term, and long-term outcome

BACKGROUND

The aim of the study is to examine the effect of concomitant aortic regurgitation (AR) on percutaneous mitral valvuloplasty (PMV) procedural success, short-term, and long-term clinical outcome. No large-scale study has explored the impact of coexistent AR on PMV procedural success and outcome.

METHODS

Demographic, echocardiographic, and procedure-related variables were recorded in 644 consecutive patients undergoing 676 PMV at a single center. Mortality, aortic valve surgery (replacement or repair) (AVR), mitral valve surgery (MVR), and redo PMV were recorded during follow-up.

RESULTS

Of the 676 procedures performed, 361 (53.4%) had no AR, 287 (42.5%) mild AR, and 28 (4.1%) moderate AR. There were no differences between groups in the preprocedure characteristics, procedural success, or in the incidence of inhospital adverse events. At a median follow-up of 4.11 years, there was no difference in the overall survival rate (P = .22), MVR rate (P = .69), or redo PMV incidence (P = .33). The rate of AVR was higher in the moderate AR group (0.9% vs 1.9% vs 13%, P = .003). Mean time to AVR was 4.5 years and did not differ significantly between patients with no AR, mild AR, or moderate AR (2.9 +/- 2.1 vs 5.7 +/- 3.6 vs 4.1 +/- 2.5 years, P = .46).

CONCLUSIONS

Concomitant AR at the time of PMV does not influence procedural success and is not associated with inferior outcome. A minority of patients with MS and moderate AR who undergo PMV will require subsequent AVR on long-term follow-up. Thus, patients with rheumatic MS and mild to moderate AR remain good candidates for PMV.

Percutaneous balloon mitral commissurotomy in indigenous versus non-indigenous Australians

BACKGROUND

Rheumatic heart disease remains a serious health issue amongst the Australian indigenous population. Percutaneous balloon mitral commissurotomy (PBMC) has become the treatment of choice in patients with symptomatic pure mitral stenosis with favourable valve morphology. There is little published data on the efficacy of PBMC in indigenous Australians.

AIMS

We sought to document differences between indigenous Australians (IA) and non-indigenous Australians (NIA) undergoing percutaneous balloon mitral commissurotomy (PBMC) at The Prince Charles Hospital and Holy Spirit Northside Hospital from 1990 to 2006.

METHODS

PBMC was performed in 327 patients using the Inoue-balloon technique (271 female, 56 male, age +/-15 years (mean+/-S.D.), (range 13-89) between March 1990 and March 2006.

RESULTS

The IA population was over represented in this cohort (11% versus an estimated 3.4% of the Queensland population) and comprised the largest non-Caucasian group. Compared with the NIA population they were younger (mean age 36 years (+/-13) versus mean 52(+/-14) years (P<0.05)). Baseline mitral valve area (MVA) was similar in the IA and NIA groups (0.96 cm(2) versus 1.08 cm(2)P=0.9). Mitral valve Echo-score was also similar between the two groups (mean score 7.36 versus 7.52 P=0.8). The IA population had higher pre-procedural mitral valve gradients (14.3 mmHg versus 11.1 mmHg, P<0.05), but less mitral valve calcification. Procedural success was achieved in 91% of both groups. Post procedural MVA (planimetry) was similar (1.98 cm(2) versus 1.84 cm(2)P=0.6), as was percent reduction in mitral valve gradient. Inadequate dilatation was seen in 1 (3%) IA and in 10 (3.6%) of the NIA group. Significant MR was seen in 2 (6%) IA patients and 11 (4%) NIA patients. There were no deaths or strokes or pericardiocenteses in either group.

CONCLUSION

The indigenous population makes up a significant proportion of patients requiring PBMC in Queensland. They present younger and with higher mitral valve gradients. The procedure is safe in both the indigenous and non-indigenous Australian population. Further research is required to establish the long-term efficacy of this procedure in indigenous Australians.

The impact of mitral valve morphology on the long-term outcome of mitral balloon valvuloplasty

BACKGROUND

The effect of mitral valve morphology (MVM) on the long-term results of mitral balloon valvuloplasty (MBV) is not well established. The aim of the study was to evaluate the impact of MVM on long-term outcome of MBV.

METHODS

Five hundred and eighteen consecutive patients (mean age, 31+/-11 years) who underwent successful MBV were followed up for 0.5-16.5 (mean, 6+/-4.5) years. Patients were divided into two groups according to their mitral echo score (MES) before MBV: group A (n=340; MES<or=8) and group B (n=178; MES>8).

RESULTS

We report the immediate and long-term clinical and echocardiographic results of the above-mentioned 518 consecutive patients. The mitral valve area was significantly larger in group A than in group B, both immediately after MBV (2.0+/-0.3 vs. 1.82+/-0.3 cm2, respectively; P<0.0001) and also at the last follow-up (1.8+/-0.33 vs. 1.5+/-0.33 cm2, respectively; P<0.0001). Restenosis occurred in 38/340 (11%) in group A vs. 73/178 (41%) in group B (P<0.0001). Actuarial freedom from restenosis at 5, 10, 15 years were 92+/-2%, 85+/-3%, 65+/-6% for group A vs. 72+/-4%, 44+/-5%, 9+/-6% for group B (P<0.001). Event-free survival rates at 5, 10, 15 years for group A were 93+/-1%, 88+/-2%, 66+/-6% vs. 82+/-3%, 59+/-6%, 8+/-7% for group B (P<0.0001). Stepwise Cox multivariate regression analysis identified MES, preprocedure functional class, and postprocedure mitral valve area<or=1.8 cm2, as predictors of restenosis (P<0.0001, P=0.014, P=0.0015, respectively); MES and age as predictors of event-free survival (P<0.0001, P<0.0001, respectively).

CONCLUSION

MBV has excellent long-term results in patients with favorable MVM. Favourable MVM is a strong predictor of good long-term outcome.

Long-Term Results (Up to 16.5 Years) of Mitral Balloon Valvuloplasty in a Series of 518 Patients and Predictors of Long-Term Outcome

OBJECTIVES

To assess the long-term results (up to 16.5 years) of mitral balloon valvuloplasty (MBV) and to identify predictors of restenosis and event-free survival.

METHODS AND RESULTS

We report the immediate and long-term clinical and echocardiographic results in 518 patients, mean age 31 +/- 11 years, who underwent successful MBV for severe mitral stenosis (MS) and were followed up for 0.5-16.5 (mean 6 +/- 4.5) years. After MBV, mitral valve area (MVA) increased from 0.84 +/- 0.2 to 1.83 +/- 0.53 cm(2) (P < 0.0001) as measured by catheter and from 0.92 +/- 0.17 to 1.96 +/- 0.29 cm(2) (P < 0.0001) as measured by two-dimensional echo. Restenosis occurred in 111 patients (21%) and it was less frequent in patients with low echo score (11%). Actuarial freedom from restenosis at 5, 10, 15 years was 85 +/- 1%, 70 +/- 3%, and 44 +/- 5%, respectively, and was significantly higher in patients with low echo score. Event-free survival (death, redo MBV, mitral valve replacement, New York Heart Association [NYHA] functional class III or IV) at 5, 10, 15 years was 89 +/- 1%, 79 +/- 2%, 43 +/- 9%, respectively, and was significantly higher for patients with low echo score. Cox regression analysis identified mitral echocardiographic score (MES) > 8 (P < 0.0001), postprocedure mitral valve area (MVA) (P = 0.0015), and preprocedure functional class (P = 0.014) as predictors of restenosis and MES (P < 0.0001) and age (P < 0.0001) and postprocedure MVA (P = 0.015) as predictors of event-free survival.

CONCLUSIONS

MBV provides excellent long-term results for selected patients with MS. The long-term outcome after this procedure can be predicted from baseline clinical and echocardiographic characteristics.

Percutaneous mitral balloon valvotomy

Percutaneous mitral balloon valvotomy (PMBV) was introduced in 1984 by Inoue who developed the procedure as a logical extension of surgical closed commissurotomy. Since then, PMBV has emerged as the treatment of choice for severe pliable rheumatic mitral stenosis (MS). With increasing experience and better selection of patient, the immediate results of the procedure have improved and the rate of complications declined. When the reported complications of PMBV are viewed in aggregate, complications occur at approximately the following rates: mortality (0-0.5%), cerebral accident (0.5-1%), mitral regurgitation (MR) requiring surgery (1.6-3%). These complication rates compare favorably to those reported after surgical commissurotomy. Several randomized trials reported similar hemodynamic results with PMBV and surgical commissurotomy. Restenosis after PMBV ranges from 4 to 70% depending on the patient selection, valve morphology, and duration of follow up. Restenosis was encountered in 21% of the author's series at mean follow-up 6 +/- 4.5 years and the 10 and 15 years restenosis-free survival rates were (70 +/- 3)% and (44 +/- 5)%, respectively, and were significantly higher for patients with favorable mitral morphology (85 +/- 3% and 65 +/- 6%), respectively (P < 0.0001). The 10 and 15 years event-free survival rates were (79 +/- 2)% and (43 +/- 9)% and were significantly higher for patients with favorable mitral morphology (88 +/- 2)% and (66 +/- 6)%, respectively (P < 0.0001). The effect of PMBV on severe pulmonary hypertension, concomitant severe tricuspid regurgitation, left ventricular function, left atrial size, and atrial fibrillation are addressed in this review. In addition, the application of PMBV in specific clinical situations such as in children, during pregnancy and for restenosis is discussed.

Long-Term Outcomes of Significant Mitral Regurgitation After Percutaneous Mitral Valvuloplasty

BACKGROUND

Mild commissural mitral regurgitation (MR) is associated with significantly higher restenosis-free survival after percutaneous mitral valvuloplasty (PMV), which suggests that different mechanisms of significant MR after PMV may have different clinical courses. We therefore analyzed long-term prognostic factors of significant MR after PMV.

METHODS AND RESULTS

Echocardiographic and clinical follow-up data on 380 patients were analyzed (286 women, mean age 44+/-11 years) who underwent PMV with the Inoue balloon technique between 1995 and 2000. Significant MR developed in 47 patients (12.4%). The survival rate at 8 years was 96+/-3% and 98+/-10% in patients with and without significant MR, respectively (P=0.084). The most frequent mechanism was commissural MR, or MR that originated at the site of successful commissurotomy, which occurred in 27 of 47 patients (57%), whereas noncommissural MR occurred in 20 (43%) patients, 12 (26%) with subvalvular damage resulting in chordae rupture and flail motion and 8 (17%) with leaflet laceration. The 8-year event-free survival rate was significantly lower in patients with significant MR than in those without (47+/-8% versus 83+/-3%, P<0.001) and was significantly higher in patients with commissural versus noncommissural MR (63+/-11% versus 29+/-11%, P<0.001). Of the 47 patients with significant MR, who were followed up for 74+/-29 months, 19 patients (40%) underwent mitral valve replacement, and 28 patients (60%) received medical treatment only. Patients with commissural MR had a significantly lower rate of mitral valve replacement than patients with noncommissural MR (15% versus 70%, P<0.001). Multivariate analysis showed that atrial fibrillation (odds ratio, 7.4; 95% CI, 1.1 to 56.4; P=0.038), mean mitral gradient immediately after PMV (odds ratio, 1.5; 95% CI, 1.1 to 2.0; P=0.009), and the mechanism of MR (odds ratio, 16.7; 95% CI, 2.3 to 122.2; P=0.005) were independent factors associated with mitral valve replacement.

CONCLUSIONS

Clinical outcome of patients with significant MR after PMV varied according to MR mechanism and the adequacy of hemodynamic improvement, which is easily assessed by echocardiography immediately after PMV.

Relation of patient age to outcome of percutaneous mitral valvuloplasty

The aim of this study was to evaluate the impact of age on immediate- and long-term outcomes of percutaneous mitral balloon valvuloplasty (PMV). PMV is the first-line treatment for patients with symptomatic mitral stenosis. However, long-term results in large series of patients from Europe and the United States have been found less favorable than those from Asia and South America involving younger patients. Six hundred ten patients who underwent 626 PMV procedures were prospectively followed for 6.1 +/- 4.10 years using clinical and echocardiographic evaluation. Patients were divided in quartiles according to age: < or =41 years (n = 163), 42 to 53 years (n = 163), 54 to 63 years (n = 142), and >63 years (n = 158). The success of PMV was defined as valve area > or =1.5 cm(2) without severe regurgitation; restenosis was defined as a loss > or =50% of initial gain, with a valve area of <1.5 cm(2). PMV success was significantly more prevalent in younger patients: 95.7% in group 1, 91.4% in group 2, 86.4% in group 3, and 83.4% in group 4 (p = 0.002). No significant differences in complications were found among all age groups, including death, cardiac tamponade, emergency mitral replacement, and any embolic events (p = NS). Event-free survival was greater in younger patients (p <0.0001), but on multivariate analysis, age was not an independent predictor of events (p = NS). Restenosis occurred in 27.9% of patients, throughout all groups (p = NS). In conclusion, PMV may be safely and effectively performed in younger and older patients. Although event-free survival was greater in younger groups, multivariate analysis did not find that age was an independent predictor of events.

Immediate and long-term follow-up of percutaneous balloon mitral valvuloplasty in pregnant patients with rheumatic mitral stenosis

Percutaneous mitral balloon valvuloplasty (PMV) can be performed during pregnancy without significant maternal risk or fetal morbidity or mortality. However, little is known about long-term follow-up results after PMV in populations of pregnant women. Thus, the present study was undertaken to determine the immediate and long-term outcomes after PMV in a large cohort of pregnant patients with severe mitral stenosis. The patient population consisted of 71 consecutive pregnant women with severe rheumatic mitral stenosis admitted to the hospital with severe congestive heart failure (New York Heart Association class III and IV) for PMV. All patients underwent clinical and obstetric evaluations, electrocardiography, and 2-dimensional and Doppler echocardiography. PMV was successful in all patients, resulting in a significant increase in mitral valve area from 0.9 +/- 0.2 to 2.0 +/- 0.3 cm2 (p <0.001). At the end of pregnancy, 98% of the patients were in New York Heart Association functional class I or II. At a mean follow-up of 44 +/- 31 months, the total event-free survival rate was 54%. The mean gestational age at delivery time was 38 +/- 1 weeks. Preterm deliveries occurred in 9 patients (13%), including 2 twin pregnancies. The remaining 66 of 75 newborns (88%) had normal weight (mean 2.8 +/- 0.6 kg) at delivery. At long-term follow-up of 44 +/- 31 months after birth, the 66 children exhibited normal growth and development and did not show any clinical abnormalities. In conclusion, PMV is safe and effective, has a low morbidity and mortality rate for the mother and the fetus, and has favorable long-term results in pregnant women with rheumatic mitral stenosis in New York Heart Association functional class III or IV.

Percutaneous transmitral commissurotomy in juvenile mitral stenosis—comparison of long term results of Inoue balloon technique and metallic commissurotomy

OBJECTIVES

To compare the immediate and long term results of percutaneous mitral valvotomy using metallic commissurotome and Inoue balloon in juvenile mitral stenosis.

BACKGROUND

Inoue balloon technique for mitral commissurotomy (IBMC) is well established and carried out worldwide in the treatment of juvenile mitral stenosis. Percutaneous mitral metallic commissurotomy (PMMC) is reported to be a cheaper and effective alternative to balloon mitral commissurotomy.

METHODS

Thirty-three patients aged less than 20 years, who underwent PMMC, were compared with 33 age and sex matched control patients who underwent IBMC. Success of valvotomy, procedure related complications, and follow-up events of the two techniques were compared.

RESULTS

Basal echocardiographic and hemodynamic data were similar in both groups. Procedural success was similar in both groups, 31/33. Complications like cardiac tamponade and mitral regurgitation (requiring or not requiring mitral valve replacement) were similar in both groups. On follow-up of more than 3 years, both groups had comparable hemodynamic parameters and restenosis rates.

CONCLUSIONS

Both IBMC and PMMC are successful in providing relief from severe juvenile mitral stenosis in terms of gain in valve area and reduction in transmitral gradient. Both techniques have similar procedural success and complication rates. The long term follow-up results are comparable at follow-up of more than 3 years.

Percutaneous valve therapies

Recent innovations have occurred in the treatment of valvular heart disease so that we now stand at the very beginning of a field that is likely to show considerable growth in the future. These innovations include the introduction of self-expanding and balloon-expandable stents containing bioprosthetic heart valves, and other valvular implants and techniques for the repair and treatment of valvular heart disease. Previously, the field of nonsurgical cardiac valve repair and replacement consisted solely of the use of balloon valvuloplasty for valvular stenosis. The ability to address aortic stenosis more definitively than with balloon valvuloplasty and to address regurgitant valve lesions will greatly expand the patients who can be treated without surgery. Percutaneous valve repair and replacement is at an early stage with a variety of techniques that are undergoing investigation. Similar to the initial development of balloon angioplasty for coronary artery disease, improvements in technology, techniques, and experience will be necessary before we can reproduce the excellent results achieved today with surgery.

The Impact of Age in the Immediate and Long-Term Outcomes of Percutaneous Mitral Balloon Valvuloplasty

BACKGROUND

Differences in age, clinical characteristics, and valve morphology may account for controversial results of percutaneous mitral balloon valvuloplasty (PMV).

METHODS

We have previously reported the immediate and long-term clinical follow-up (50 +/- 45 months) of 879 patients who underwent PMV at the Massachusetts General Hospital. In the present study, we used this database to determine the impact of age in the immediate and long-term outcome of PMV. For purpose of analysis, these patients were divided into four age groups: group 1 (< or =35 years), group 2 (36-55 years), group 3 (56-75 years), and group 4 (>75 years).

RESULTS

The incidence of atrial fibrillation, calcified valves under fluoroscopy, higher echocardiographic score, New York Heart Association (NYHA) class IV and pre-PMV mitral regurgitation (MR) increased with patient's age. As patients became older, a lower post-PMV mitral valve area (2.1 +/- 0.7, 2.0 +/- 0.6, 1.8 +/- 0.6, and 1.6 +/- 0.6; P < 0.0001) and progressive decrease in procedural success (81.4%, 80.5%, 65.3%, and 53%; P < 0.0001) were observed. Younger age was identified as an independent predictor of PMV success by multiple stepwise logistic regression (odds ratio [OR]: 3.33; confidence interval [CI]: 1.41-7.69, P = 0.006). Furthermore, age was identified as an independent predictor of long-term events by Cox regression analysis (risk ratio [RR]: 1.02; CI: 1.01-1.03, P < 0.00001). However, the effect of age seemed to be blunted by the morphology of the valve at follow-up, as patients with echocardiogram score >8 in groups 2, 3, and 4 presented similar combined event-free survival (death, mitral valve replacement, or redo PMV).

CONCLUSION

Age is an important predictor of immediate and long-term outcomes after PMV, particularly in patients with optimal mitral valve morphology. (

Feasibility, safety, and morphologic predictors of outcome of repeat percutaneous balloon mitral commissurotomy

Early and mid-term results of repeat percutaneous balloon mitral commissurotomy (PBMC) were analyzed in 35 patients with symptomatic valvular restenosis: 12 patients (34%) after first successful PBMC and 23 patients (66%) after successful surgical closed mitral commissurotomy. Twenty-one patients had bilateral fused commissures, and 14 patients had unilateral or bilateral split commissures. Mitral valve area gain was significantly greater in the group with fused commissures compared with the group with split commissures (0.6 +/- 0.2 vs 0.3 +/- 0.2 cm(2), respectively, p = 0.04).

Long-term clinical and echocardiographic results after successful mitral balloon valvotomy and predictors of long-term outcome

AIMS

To assess the long-term outcome of mitral balloon valvotomy (MBV) and identify predictors of restenosis- and event-free survival.

METHODS AND RESULTS

We report the immediate and long-term clinical and echocardiographic results in 493 patients, mean age 31+/-11, who underwent successful MBV and were followed-up for 0.5-15 years (median 5+/-3) with clinical and echocardiographic examination. After MBV, mitral valve area increased from 0.84+/-0.2 to 1.83+/-0.53 cm(2) (P<0.0001) as measured by catheter and from 0.92+/-0.17 to 1.96+/-0.29 cm(2) as measured by two-dimensional echo. Restenosis occurred in 86/493 (17.4%) patients and it was less frequent in patients with low echo score. Actuarial freedom from restenosis at 5, 7, 10, and 13 years were 89+/-1, 81+/-2, 68+/-3, and 51+/-6%, respectively, and was significantly higher in patients with low echo score. Event-free survival (death, redo MBV, mitral valve replacement, New York Heart Association functional Class III or IV) at 5, 7, 10, and 13 years were 92+/-1, 87+/-2, 80+/-3, and 74+/-3%, respectively, and was significantly higher for patients with low echo score. Cox regression analysis identified mitral echocardiographic score (MES) >8 as predictors of restenosis (P=0.0004) and MES and age as predictors of event-free survival (P=0.0003 and 0.004, respectively).

CONCLUSION

MBV has excellent long-term results for selected patients with mitral stenosis. The long-term outcome after this procedure can be predicted from baseline clinical and valvular characteristics.

Initial clinical experience with intracardiac echocardiography in guiding balloon mitral valvuloplasty: technique, safety, utility, and limitations

The objective of this study was to examine the feasibility and technique of intracardiac echocardiography during percutaneous balloon mitral valvuloplasty. Echocardiographic imaging is commonly used during mitral valvuloplasty. Intracardiac echocardiography is a newer technology that may provide superior imaging during complex valvular interventions. Intracardiac echocardiography and transthoracic echocardiography were performed in 19 patients undergoing percutaneous balloon mitral valvuloplasty. Intracardiac ultrasound images were obtained via the femoral vein in all patients. Imaging projections and catheter locations that were useful for the performance of mitral valvuloplasty were defined. Intracardiac echocardiography guided transseptal puncture, augmented the assessment of valve apparatus deformity, facilitated balloon positioning across the mitral valve, and permitted postprocedural valvular assessment including identification of mitral regurgitation with color Doppler. Intracardiac echocardiography provided essential imaging guidance and procedural monitoring during percutaneous mitral valvuloplasty.

Immediate and long-term results of percutaneous mitral balloon valvotomy in asymptomatic or minimally symptomatic patients with severe mitral stenosis

The purpose of this study was to evaluate the safety and value of percutaneous mitral balloon valvotomy (PMBV) in asymptomatic or minimally symptomatic patients with severe mitral stenosis (MS). There are very limited data supporting the concept of PMBV in asymptomatic or minimally symptomatic patients with severe MS. We analyzed the results of 539 consecutive patients with severe MS who underwent PMBV at our hospital. Patients were divided according to their symptoms at the time of PMBV into group A (55 patients), who had few or no symptom (NYHA class 1 or 2), and group B (484 patients), who had severe symptom (NYHA class 3 or 4). Patients had clinical and echocardiographic follow-up for 0.5-15 years. There was no significant difference in baseline characteristics between the two groups. The immediate mitral valve area (MVA) was equal in both groups. The follow-up MVA was larger in group A (1.9 +/- 0.38 vs. 1.7 +/- 0.4 cm(2); P = 0.002), and restenosis occurred in 11% in group A vs. 23% in group B (P = 0.023). Actuarial freedoms from restenosis at 5, 10, and 13 years were significantly higher for group A than for group B (97% +/- 2%, 77% +/- 9%, 77% +/- 9% vs. 85% +/- 1%, 62% +/- 3%, 39% +/- 5%; P = 0.0018). Atrial fibrillation at follow-up was encountered in 11% in group A vs. 20% in group B (P = 0.042). There was a significant reduction of the left atrial size in both groups. Event-free survivals at 5, 10, and 13 years were higher for group A than for group B (97% +/- 2%, 80% +/- 9%, 80% +/- 9% vs. 86% +/- 1%, 65% +/- 3%, 42% +/- 3%; P = 0.0018). This study demonstrated excellent immediate results of PMBV in asymptomatic or minimally symptomatic patients with severe MS and long-term results are better compared to the reported natural history of such patients. We recommend mitral balloon valvotomy (MBV) for patients with severe MS with few or no symptoms, provided the valve morphology is suitable for MBV.

Consequence of atrial fibrillation and the risk of embolism after percutaneous mitral commissurotomy: The necessity of the maze procedure

BACKGROUND

We sought to investigate the incidence and risk of embolism after percutaneous balloon mitral commissurotomy (PMC) and delineated the necessity of the maze procedure in patients with atrial fibrillation (AF).

METHODS

Clinical records of 326 patients, who underwent PMC between April 1988 and March 2003, and 162 patients, who underwent mitral valve surgery (MVS) combined with the maze procedure (MVS/maze) in the same period, were reviewed. We examined the consequence of cardiac rhythm and the incidence and risk of embolism after PMC. Next our current criteria for indication of the maze procedure, which included duration of AF less than 10 years, voltage of f wave on electrocardiography greater than 0.1 mV, cardiothoracic ratio less than 70%, and left atrial dimension less than 70 mm, were applied to all patients. These criteria were satisfied by 190 patients of PMC (PMC group) and 114 patients of MVS/maze (MVS/maze group) and the early and late results of the two groups were compared.

RESULTS

Thirty-eight patients suffered from embolic complications after PMC. Of these 33 patients experienced AF before intervention. The actuarial embolism-free rate at 10 years was 81.9% in patients with AF before PMC and 92.9% in patients with sinus rhythm before PMC (p = 0.01). Univariate predictors of embolism after PMC included previous embolic history (p = 0.01), AF (p = 0.01), pressure gradient (p = 0.01), age (p = 0.03), and mitral valve area (p = 0.04). Multivariate analysis identified AF as the independent predictor of embolism in the late follow-up period (p = 0.03). In a comparative study of the selected patients the actuarial AF-free rates after MVS/maze were 89.9% at 1 year and 85.7% at 5 years and were significantly higher than those of 17.3% at 1 year and 4.2% at 5 years after PMC (p < 0.0001). The actuarial embolism-free rate in the MVS/maze group was 98.0% at 5 years and was significantly higher than that of 84.8% at 5 years and 82.4% at 10 years in the PMC group (p = 0.01).

CONCLUSIONS

PMC alone is not sufficient with regard to sinus rhythm recovery and prevention of embolism. Surgical treatment concomitant with the maze procedure may be beneficial for patients with AF.

Effect of electrical stimulus parameters on the development and propagation of action potentials in short excitable fibres

Intracellular action potentials (IAPs) produced by short fibres in response to their electrical stimulation were analysed. IAPs were calculated on the basis of the Hodgkin-Huxley (1952) model by the method described by Joyner et al. (1978). Principal differences were found in processes of activation of short (semilength L less than 5 lambda) and long fibres under near-threshold stimulation. The shorter the fibre, the lower was the threshold value (Ithr). Dependence of the latency on the stimulus strength (Ist) was substantially non-linear and was affected by the fibre length. Both fibre length and stimulus strength influenced the IAP amplitude, the instantaneous propagation velocity (IPV) and the site of the first origin of the IAP (and, consequently, excitability of the short fibre membrane). With L less than or equal to 2 lambda and Ithr less than or equal to Ist less than or equal to 1.1Ithr, IPV could reach either very high values (so that all the fibre membrane fired practically simultaneously) or even negative values. The latter corresponded to the first origin of the propagated IAP, not at the site of stimulation but at the fibre termination or at a midpoint. The characters of all the above dependencies were unchanged irrespective of the manner of approaching threshold (variation of stimulus duration or its strength). Reasons for differences in processes of activation of short and long fibres are discussed in terms of electrical load and latency. Applications of the results to explain an increased jitter, velocity recovery function and velocity-diameter relationship are also discussed.