Comparison of results of percutaneous balloon mitral commissurotomy in patients aged ≥65 years with those in patients aged <65 years

Comparison of results of percutaneous balloon mitral commissurotomy in patients aged ≥65 years with those in patients aged <65 years

Comparison of Results of Percutaneous Balloon Mitral Commissurotomy in Patients Aged >65 Years With Those in Patients Aged 65 years old (71 ⴞ 6 years)...

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Comparison of Results of Percutaneous Balloon Mitral Commissurotomy in Patients Aged >65 Years With Those in Patients Aged <65 Years Richard A. Krasuski, MD, John J. Warner, MD, Gail Peterson, MD, Andrew Wang, MD, J. Kevin Harrison, MD, Katherine B. Kisslo, RDCS, and Thomas M. Bashore, MD Percutaneous balloon mitral commissurotomy (PBMC) is now first-line therapy in patients with symptomatic mitral stenosis (MS) and favorable valve morphology. Unfortunately, the outcome of Medicare-aged patients undergoing this procedure has not previously been defined. The results of PBMC in 55 patients >65 years old (71 ⴞ 6 years) with moderate or severe MS were compared with 268 younger patients (47 ⴞ 10). Preprocedural New York Heart Association functional class and pulmonary pressures did not differ. The older patients had higher blood pressure, were more likely to be in atrial fibrillation and had higher valve scores (9.9 ⴞ 2.5 vs 8.6 ⴞ 2.2, p ⴝ 0.001). Procedural success was higher in the younger group (71% vs 55%, p ⴝ 0.013), with a greater increase in mitral valve area. Complications were similar in both groups and there were no periprocedural deaths. At 6 months a significant im-

provement in function class was seen in both groups. Restenosis, as assessed by serial echocardiography, occurred at a rate of 0.06 cm2/year in both groups, and functional class remained unchanged over 3 years. Event-free survival was similar at 48 months: 76% in the younger group and 69% in the older group. Our data thus demonstrates that PBMC can be safely performed in the Medicare-aged population. Despite less acute success in the older population, complication rates do not differ and decrement in valve area over time occurs at a similar rate. Functional class remains improved and event-free survival over 4 years appears similar in both groups. PBMC should thus be offered to patients with MS and suitable anatomy regardless of their age. 䊚2001 by Excerpta Medica, Inc. (Am J Cardiol 2001;88:994 –1000)

ince 1984 the technique of percutaneous balloon mitral commissurotomy (PBMC) or valvuloplasty S has undergone substantial modifications, with short-

gitation (MR) (ⱕ2⫹ by left ventriculography on a Sellers9 scale of 1 to 4⫹). Patients with extensive mitral valve calcification or subvalvular thickening were generally considered for mitral valve replacement surgery. However, PBMC was offered to these patients if they were considered poor surgical candidates.

and long-term success comparable to open surgical commissurotomy.1– 8 Although initially performed in patients considered too high risk for surgery, PBMC is now used as first-line therapy in all patients with symptomatic mitral stenosis (MS) and suitable valve morphology. Information regarding the procedural outcome and long-term follow-up in patients ⱖ65 years of age is lacking. This study compares the shortand long-term results of PBMC in patients aged ⱖ65 years with those of patients aged ⬍65 years.

METHODS

Patients: All patients with at least moderate MS (ⱕ1.5 cm2 on cardiac catheterization) undergoing Inoue PBMC at Duke University Medical Center between July 1, 1990, and November 4, 1999, were included for analysis. Patients were selected for this procedure based on clinical status, suitable valve morphology, and the absence of significant mitral regurFrom the Division of Cardiology, Department of Medicine, Duke University Medical Center, Durham, North Carolina. Manuscript received April 17, 2001; revised manuscript received and accepted June 21, 2001. Address for reprints: Thomas M. Bashore, MD, Box 3012, Duke University Medical Center, Durham, North Carolina 27710. E-mail: [email protected].

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©2001 by Excerpta Medica, Inc. All rights reserved. The American Journal of Cardiology Vol. 88 November 1, 2001

Cardiac catheterization and commissurotomy technique: Informed consent was obtained for fol-

low-up from all patients according to a protocol approved by the Duke University Medical Center Investigations Review Board. Diagnostic right and left heart catheterizations were performed, with measurement of baseline hemodynamic data. Cardiac output was determined using an assumed Fick calculation. Simultaneous left atrial and left ventricular pressures were recorded after transseptal catheterization to determine the transmitral pressure gradient, and mitral valve area was calculated using the Gorlin formula.10 Mitral commissurotomy was performed using sequential dilatation of the Inoue balloon (Toray Industries, Inc., Tokyo, Japan). Intraprocedural echocardiography was used for the last 57 patients and the procedure was terminated when the mitral commissures appeared open or when an increase in MR was detected by color Doppler. Before the use of intraprocedural echocardiography, procedure termination was determined by a decrease in mitral pressure gradient by catheterization or an increase in the V wave of the left atrial pressure 0002-9149/01/$–see front matter PII S0002-9149(01)01976-2

tracing, suggesting worsened MR. Hemodynamic measurements were repeated after the procedure. Oxygen saturations were measured to detect the presence ⱖ65 yrs ⬍65 yrs p of interatrial shunting, and the calculated systemic Variable (n ⫽ 55) (n ⫽ 268) Value blood flow was used for determination of the cardiac Age (yrs) (mean ⫾ SD) 71 ⫾ 6 47 ⫾ 10 output and calculation of the final mitral valve area if Men 6 (11%) 40 (15%) 0.438 a ⱖ1.3 left-to-right shunt was present. ⬎1 Coronary artery 4 (7.3%) 14 (5.2%) 0.523 Procedural success was defined by a mitral valve narrowed ⱖ75% area ⬎1.5 cm2 or by a ⱖ50% increase in mitral valve NYHA functional class 2.8 ⫾ 0.6 2.8 ⫾ 0.6 0.680 (mean ⫾ SD) area by cardiac catheterization and ⬍2⫹ MR on anAtrial fibrillation 29 (53%) 76 (28%) 0.001 giography. Previous open 2 (3.6%) 44 (16%) 0.010 Echocardiography: Two-dimensional and Doppler commissurotomy echocardiographic examinations were performed by a Previous balloon 1 (1.8%) 6 (2.2%) 1.000 single operator using a phase-arrayed scanner with a commissurotomy 2.5-MHz transducer (Hewlett Packard, Andover, MasNYHA ⫽ New York Heart Association. sachusetts). Examinations were performed before PBMC, 24 hours after the procedure, 6 months after the procedure, 1 year after the proceTABLE 2 Baseline Hemodynamic and Echocardiographic Characteristics of Patients Undergoing PBMC dure, and yearly thereafter. Standard echocardiographic images were obHemodynamics ⱖ65 yrs ⬍65 yrs p Value tained in the parasternal long- and Pulmonary artery mean (mm Hg) 32.8 ⫾ 10.3 33.3 ⫾ 11.3 0.774 short-axis views, apical 2- and Aortic mean (mm Hg) 98.6 ⫾ 15.0 91.5 ⫾ 13.1 0.0005 4-chamber views, and subcostal 2 2.4 ⫾ 0.5 2.7 ⫾ 0.6 0.0002 Cardiac index (L/min/m ) view. Postprocedural echocardioMean mitral valve gradient 10.5 ⫾ 4.0 13.1 ⫾ 4.9 0.0003 Mitral valve area (cm2) 1.1 ⫾ 0.3 1.1 ⫾ 0.2 0.914 graphic data were interpreted withEcho measurements out knowledge of cardiac catheterMean mitral valve gradient 7.7 ⫾ 2.3 9.6 ⫾ 4.2 0.0001 ization results. Mitral valve morphol2 Planimetered mitral valve area (cm ) 1.2 ⫾ 0.4 1.2 ⫾ 0.3 0.900 ogy was assigned a score based on Doppler mitral valve area (cm2) 1.3 ⫾ 0.3 1.1 ⫾ 0.3 0.007 the Wilkins scoring system for MS,11 Valve score Total 9.9 ⫾ 2.5 8.6 ⫾ 2.1 ⬍0.0001 with a score of 1 to 4 for each of 4 Mobility 2.5 ⫾ 0.6 2.2 ⫾ 0.7 0.005 morphologic characteristics: leaflet Thickness 2.8 ⫾ 0.8 2.4 ⫾ 0.8 0.001 mobility, thickness, calcification, and Subvalve 2.7 ⫾ 0.8 2.6 ⫾ 0.8 0.229 subvalvular thickening. Mitral inflow Calcium 2.0 ⫾ 0.9 1.5 ⫾ 0.8 ⬍0.0001 was measured using continuousValues are expressed as mean ⫾ SD. wave Doppler from the apical view. Mean mitral gradient was calculated by planimetry of the diastolic flow velocity and integration of the inTABLE 3 Procedural Results of Mitral Commissurotomy stantaneous Doppler pressure gradiⱖ65 yrs ⬍65 yrs p Value ents throughout diastole, divided by the diastolic filling period. Results Procedural success 30 (55%) 192 (72%) 0.013 were averaged over 3 beats for paPostprocedural Catheterization Data tients in sinus rhythm and 6 beats for patients in atrial fibrillation. Calcula2 1.6 ⫾ 0.5 1.8 ⫾ 0.5 0.004 Final mitral valve area (cm ) tion of the mitral valve area was per% Improvement in valve area 48.3 ⫾ 42.3 67.2 ⫾ 44.6 0.004 formed both by using the pressure Mean mitral valve gradient (mm Hg) 6.1 ⫾ 2.6 6.9 ⫾ 3.4 0.053 % Decrease in mitral valve gradient 39.8 ⫾ 18.8 45.3 ⫾ 21.4 0.078 halftime method12 and by planimetry of the mitral valve orifice in early Postprocedural Echocardiographic Data diastole from the short-axis view, 2 with careful adjustment of the scanPlanimetered mitral valve area (cm ) 1.7 ⫾ 0.4 1.9 ⫾ 0.4 0.005 ning plane to record the maximal or% Improvement in mitral valve area 40.7 ⫾ 63.3 57.1 ⫾ 41.4 0.021 Doppler mitral valve area (cm2) 1.7 ⫾ 0.4 1.8 ⫾ 0.4 0.158 ifice area at the leaflet tips. The de% Improvement in mitral valve area 39.0 ⫾ 33.0 63.5 ⫾ 49.4 ⬍0.0001 gree of MR was determined using Mean mitral valve gradient (mm Hg) 6.0 ⫾ 2.2 6.2 ⫾ 2.7 0.687 color-flow Doppler, and assigned a % Decrease in gradient 20.5 ⫾ 27.7 29.2 ⫾ 33.1 0.054 value of 0 to 4⫹ depending on the 6-mo Functional Data spatial extent of color flow relative to the left atrial area.13 NYHA functional class 1.9 ⫾ 0.6 1.5 ⫾ 0.7 0.0007 Clinical follow-up: Patients were % Improvement in class 31 ⫾ 23.9 44.4 ⫾ 25.6 0.001 questioned regarding functional staValues are expressed as mean ⫾ SD. tus preprocedure at 6 months, at 1 Abbreviation as in Table 1. year, and yearly thereafter. Clinical TABLE 1 Baseline Demographic Data of Patients Undergoing PBMC

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FIGURE 1. Mitral valve area as assessed by planimetry of the mitral valve using 2-dimensional echocardiography. Both age groups began with similar baseline mitral valve areas. Younger patients achieved more efficacious enlargement of the mitral orifice with PBMC. Restenosis occurred at a similar rate of 0.06 cm2 valve area loss per year in both groups.

assessment was made at the time of echocardiographic examination in patients returning for echocardiographic follow-up, by response to mailed questionnaires, by telephone contact with the patient or treating physician, or by review of medical records. Patients were classified according to the New York Heart Association classification for congestive heart failure symptoms on a scale of 1 to 4. Adverse clinical events were defined as death, mitral valve replacement, or repeat PBMC. Statistical analysis: Clinical, echocardiographic, and catheterization data were prospectively entered in the Duke University Mitral Valvuloplasty Database. Data were compiled and analyzed using a statistical software package (SAS, SAS Institute; Cary, North Carolina), and comparison of continuous variables was performed using the paired and 2-sample t test, and comparison of dichotomous variables using the chisquare or Fisher’s exact tests when appropriate. Data are presented as mean ⫾ SD for continuous variables, and as a number (percentage) for dichotomous variables. A p value ⬍0.05 was considered statistically significant. In addition to standard statistical analysis, a mixed statistical model was used to examine restenosis more carefully. Mixed models permit the determination of a rate of change for each individual patient, and examine how it contributes to the calculation of a rate of 996 THE AMERICAN JOURNAL OF CARDIOLOGY姞

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change for the entire population.14 Survival analysis was performed using the “proc lifetest” function in SAS.

RESULTS

Patient population: Three hundred twenty-three symptomatic patients with moderate or severe MS underwent PBMC between September 1990 and November 1999. Fifty-five of these patients were aged ⱖ65 years (average age 71 ⫾ 6) and constituted 17% of the patient population. The average age of the remaining patients (the younger group) was 47 ⫾ 10 years. Demographics and baseline hemodynamics: The baseline demographic, echocardiographic, and hemodynamic data for the 2 patient groups are listed in Tables 1 and 2. Preprocedural functional class and degree of pulmonary hypertension did not differ between the 2 groups. The older patients had higher mean systemic blood pressures (99 ⫾ 15 vs 92 ⫾ 13, p ⫽ 0.002) and were more likely to be in atrial fibrillation (53% vs 29%, p ⫽ 0.001). The mean mitral valve gradient was significantly higher in the younger group by catheterization (13.1 ⫾ 4.9 vs 10.5 ⫾ 4.0, p ⬍0.001) and by echocardiography (9.6 ⫾ 4.2 vs 7.7 ⫾ 2.3, p ⫽ 0.001). Although mitral valve areas determined by catheterization did not differ between the 2 groups, mitral valve scores were significantly higher in the older population (9.9 NOVEMBER 1, 2001

FIGURE 2. New York Heart Association (NYHA) functional class improved significantly with PBMC in both groups, although to a greater degree in younger patients. Improvement is noted to be sustained over time in both groups.

⫾ 2.5 vs 8.6 ⫾ 2.2, p ⬍0.001), with statistically significant differences seen in all categories except in the assessment of the subvalvular apparatus. Acute procedural results: The acute results of PBMC for both groups are listed in Table 3. Procedural success was higher in the younger group (71% vs 55%, p ⫽ 0.013), with a greater increase in mitral valve area on cardiac catheterization (67% vs 48%, p ⫽ 0.004) and on echocardiography (57% vs 41%, p ⫽ 0.021). Complications, however, were similar in the elderly group, with significant MR noted on ventriculography in 3 of 55 older patients (5.5%) and 24 of 270 younger patients (8.9%) after PBMC (p ⫽ 0.592). Six patients (2.2%) in the younger group underwent urgent or emergent mitral valve replacement surgery because of MR, whereas no older patients underwent immediate surgery. There were no periprocedural deaths in either group. Six-month functional follow-up: Six months after the procedure, a statistically significant improvement in New York Heart Association congestive heart failure function class was seen in both groups. Consistent with the echocardiographic and hemodynamic data, however, heart failure class was better at this time in the younger group (1.5 ⫾ 0.7 vs 1.9 ⫾ 0.6, p ⬍0.001).

Long-term echocardiographic and functional follow-up: Patients in the age groups with at least 1

year of completed follow-up were compared regarding progression of MS, MR, and New York Heart Association function class. Despite the initial disparity in

valve area after the procedure, echocardiographic restenosis of the mitral valve appeared to occur at a similar rate (Figure 1). A mixed-model analysis confirmed a similar loss of mitral valve area of approximately 0.06 cm2/year in both groups. Consistent with the slow progression of restenosis, functional class did not significantly change over a 3-year time span (Figure 2). However, MR appeared to progress over time in the older population, while the severity remained unchanged in younger patients (Figure 3). Event-free survival: Using survival analysis techniques, the 2 patient groups were compared with regard to a composite end point of all-cause mortality, repeat PBMC, and surgical commissurotomy or mitral valve replacement. Confirmed survival time ranged from 1 day after the procedure to 109 months in the younger group, and 1 day after the procedure to 72 months in older patients. Figure 4 illustrates the Kaplan-Meyer survival curves for both populations. Very similar results were seen in both groups, with 75.8% of the younger group and 68.5% of the older group experiencing event-free survival at 48 months (p ⫽ 0.920) for any difference between the 2 strata. Forty-one patients (15.3%) in the younger group and 5 patients (9.1%) in the older group underwent mitral valve replacement surgery during the follow-up period. Five patients (1.9%) died in the younger group and 4 died (7.3%) in the older group. One patient in each group required repeat PBMC.

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FIGURE 3. Progression of MR as assessed by color Doppler during echocardiography. Both groups noted a small but significant increase in MR after PBMC. Although stable over time in the younger patients, MR appeared to increase over time in the elderly patients.

DISCUSSION Despite the growing number of older patients undergoing PBMC (17% of patients undergoing PBMC at our institution), only a few clinical studies have examined the short- and long-term outcomes of this procedure in the elderly.15–21 Perhaps the most striking difference between the younger and elderly groups in this study was the echocardiographic valve score. An echo score ⬍8 has previously been shown to predict a favorable result from PBMC.11 The mean echo score of the elderly group was almost 10 (range 4 to 16). Valves in the elderly group were significantly less mobile as graded by Wilkin’s echo score (2.5 ⫾ 0.6 vs 2.2 ⫾ 0.7, p ⫽ 0.005), had more leaflet thickening (2.8 ⫾ 0.8 vs 2.4 ⫾ 0.8, p ⫽ 0.001), and were considerably more calcified (2.0 ⫾ 0.9 vs 1.5 ⫾ 0.8, p ⬍0.0001). This difference in echo morphology may imply more advanced rheumatic valve damage. As expected, procedural success was greater in the younger group, likely the result of the more favorable valve morphology (lower Wilkin’s score). The final mitral valve area was also larger in the younger group (1.8 ⫾ 0.5 vs 1.6 ⫾ 0.5 cm2, p ⫽ 0.004) as was the mean percent increase in valve area. Despite less successful opening of the valve, PBMC was performed with very little morbidity in the older group as well as with considerable clinical success. MR, the most common adverse event during PBMC, occurred 998 THE AMERICAN JOURNAL OF CARDIOLOGY姞

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at a similar rate in both groups, and no older patients required emergent surgery to replace a regurgitant mitral valve. In some reports, many of the elderly patients in this study would not have been considered candidates for PBMC based on their echocardiographic morphology. The unique “hour-glass” shape of the Inoue balloon is a particular advantage in the elderly group of patients with advanced fibrosis and calcium. This balloon characteristic allows the operator to fix the balloon at the mitral annular level and effectively dilate even the more rigid commissures. Stepwise balloon inflation with a slow, progressive increase in balloon diameter, and the use of intraprocedural echocardiography to assess valve opening and regurgitation have recently been demonstrated to lower the incidence of MR,22 and have become standard practices at our institution. Both groups experienced significant improvement in symptoms, although the younger patients were less symptomatic (New York Heart Association function class 1.5 ⫾ 0.5 vs 1.9 ⫾ 0.6, p ⬍0.001) after the procedure. This may be related to the greater prevalence of atrial fibrillation in the elderly population.23 Importantly, the results of PBMC appeared to be persistent in both groups. Both younger and elderly patients experienced restenosis of approximately 0.06 cm2/year, a rate similar to previously published data, NOVEMBER 1, 2001

FIGURE 4. Kaplan-Meier survival analysis for both patient groups. End points were defined as repeat PBMC, mitral valve replacement surgery, and death. At 48 months, no difference was seen in event-free survival (75.8% in the younger patients and 68.5% in the elderly patients).

and no significant progression of symptoms was noted over 3 years in either group. MR appeared to become slightly more severe in the elderly population over time, while remaining constant in younger patients. The reason for this difference is not clear, although it may be related to a greater severity of disease and extent of mitral valve involvement. Age-specific changes in peripheral vasculature resistance have also been described,24 and increases in vascular resistance and afterload with advanced age may contribute to the progression of regurgitation. One of the most important and encouraging findings of this study is the long-term survival and freedom from surgery or repeat PBMC in both groups. Survival analysis determined no difference between the elderly and younger groups at 4 years. As expected, non–age-adjusted mortality was higher in the elderly group. Younger patients were, however, more likely to undergo surgical replacement of mitral valves over this time period. This may be a result of more procedure-related MR in younger patients or a greater reluctance to perform operations in older patients. The feasibility and immediate safety of PBMC in the elderly has been previously described. Tuzcu and colleagues15 reported a 46% success rate in 99 patients using a definition similar to the one used in this study. Complications occurred in 11% of patients including 3 deaths, which occurred early in their experience. Iung et al25 reported a success rate of 66% and 4% procedural mortality in a cohort of 75 patients aged ⱖ70 years. Our procedural success rate falls between the results of these 2 studies, although our

complication rate was significantly lower. Complication rates have recently been reduced as a result of technical advances. These include preprocedural transesophageal echocardiography to exclude left atrial thrombus and reduce thromboembolic risk, physician familiarity with transseptal technique to reduce the risk of pericardial tamponade, and intraprocedural echocardiography to ensure adequate dilatation and reduce the incidence of severe MR. Limited data are available on the long-term results of PBMC in the elderly. Sutaria et al21 found an event-free survival of 39% at 3 years and 28% at 5 years in a cohort of 80 patients aged ⱖ70 years undergoing PBMC. Iung et al,25 in a similar population, found the 4-year actuarial survival rate to be 59%, with 31% of patients requiring surgery over this period. Neither study used echocardiographic follow-up for assessing valvular restenosis or MR progression. In fact, our study is the first report of serial echocardiography after PBMC in the elderly population. These data confirm that age should not be a limiting feature in offering PBMC to patients with MS. 1. Dean LS. Percutaneous transvenous mitral commissurotomy: a comparison to

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