Comparison of lnoue single-balloon versus double-balloon technique for percutaneous mitral valvotomy The results of percutaneous mitral valvotomy by means of the moue single-balloon (N = 85, group 1) and the double-balloon (N = 322, group 2) techniques were compared in a nonrandomized study. The groups were not significantly different with regard to age, sex, calcification, or hemodynamic values before percutaneous mitral valvotomy. After percutaneous mitral valvotomy, patients in both groups had significant hemodynamic and clinical improvement. The increases in mitral valve area and cardiac output and the decreases in mitral valve gradient, mean pulmonary artery pressure, and mean left atrial pressure were greater in group 2. Mitral valve area determined by the Gorlin method increased 191% in group 2 and 108% in group 1; Doppler-determined mitral valve area increased 133% in group 2 and 98% in group 1. Optimal results were achieved in 93% of the patients in group 2 and 78% in group 1 (p 5 0.0001). In group 1, 8% of patients had a left-to-right shunt as shown by angiography versus 14% in group 2 (p 5 0.05). In group 2, 46% of patients had at least a 1 + increase in mitral regurgitation versus 52% in group 1. Among the patients who had an increase in mitral regurgitation, 36% of those in group 1 versus 9% in group 2 had a 2+ or more increase (p I 0.001). The mean balloon diameter to anulus ratio was larger in group 2, and the larger the balloon diameter to anulus ratio, the greater the increase in mitral valve area. Long-term follow-up will be needed to determine whether or not the immediate hemodynamic superiority of the double-balloon technique is clinically important. (AM HEART J 1992;123:942.)

Carlos E. Ruiz, MD, PhD, He Ping Zhang, MD, Carlos Macaya, MD,” Edgar H. Aleman, MD, John W. Allen, MD, and Francis Y. K. Lau, MD. Los Angeles, Calif.

Percutaneous balloon mitral valvotomy, first described by Inoue et a1.l in 1984, is considered a safe and effective nonsurgical alternative to surgical mitral valve commissurotomy for treatment of severe rheumatic mitral stenosis.2-16Two major techniques have been described: the Inoue single-balloon methodl and the double-balloon method.14 Both techniques produce an increase in mitral valve area and improvements in hemodynamic values and functional status immediately after the procedure.3, 4,8,13,15,17-lg Some investigator.@> l8 report superior results with the double-balloon technique; others13 report similar results with either technique. From the Department of Interventional Cardiology, The Hospital of the Good Samaritan, Loma Linda tal Universitario San Carlos, University of Madrid. Received

for publication

Reprint requests: Carlos Cardiology, The Heart Loma Linda University, 411134632

942

April

8, 1991;

Sept.

The Heart Institute, University; and BHospi-

20, 1991.

E. Ruiz, MD, PhD, Department Institute, The Hospital of the 616 S. Witmer St., Los Angeles,

of Interventional Good Samaritan, CA 90017-2395.

In this nonrandomized study we compared the immediate hemodynamic results, complications, and clinical improvement achieved with the Inoue singleballoon and the double-balloon techniques. METHODS Patients. From February 1986through April 1990,a total of 407 consecutive patients underwent percutaneous

mitral valvotomy with the use of the Inoue single-balloon (N = 85, group 1) or the double-balloon (N = 322, group 2) technique. Patient characteristics are shown in Table I. Age, sex and degree of calcification were similar in both groups. Procedures. Procedures were performed as previously described.l, l2 Each patient gave informed consent for the procedure as approved by the institutional review board. Most patients were taking oral anticoagulants, which were discontinued 48 to 72 hours before the procedure. Balloon size was selected according to the size of the anulus as measured by echocardiography. The balloon/anulus (B/A) diameter ratio was calculated as balloon diameter divided by anulus diameter. When a double-balloon was used, the balloon diameter was the sum of two balloon diameters.

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Inoue versus double-balloon

Table 1. Demographic characteristics of 407 patients undergoing percutaneous mitral balloon valvotomy: Inoue single-balloon versus double-balloon technique Inoue single balloon (N = 85)

Characteristics Age Sex

47 f

(yr)

Male Female Calcification o-1+ 2-4+ Atria1 fibrillation NYHA functional II III-IV NYHA,

New York

13

n

lnoue

mitral valvotomy

943

Balloon

Double balloon (N = 322) 45 + 14

14 (16%) 71 (84%)

55 (17%) 267 (83%)

49 (58%) 36(42X) 41(48%)

179 (56%) 143(44X) 110 (34%)*

43 (51%) 42(49%)

97 (30%)? 225(70%)

p-O.WOl

WA(D)

p.o.wo1

p.0.0001

WA(G)

CO

MVG

m-PAP

m-LAP

class

Heart

Association.

‘p 5 0.05. tp 5 0.001.

Methods of assessment. Prevalvotomy and postvalvotomy hemodynamic values were compared between the groups. Changes in absolute values, which may more accurately reflect a difference between the two techniques because they do not depend on values before valvotomy, were compared. Finally, percentage changes in values before and after the procedures were also compared between groups. Cardiac output was measured by thermodilution unless severe tricuspid regurgitation was present, in which case the Fick method was used. Mitral valve area was calculated by means of the Gorlin formula and the Doppler pressure half-time method. Postvalvotomy mitral valve area was measured by means of the Gorlin formula immediately after valvotomy and by the Doppler method within 24 hours after valvotomy. Results of valvotomy were considered optimal if the mitral valve area increased to ~1.50 cm2 and the percentage increase was 250%. Ventriculography was performed to determine severity of mitral regurgitation, which was graded on a 0+ (no regurgitation) to 4+ (severe) scale by the primary operator according to the degree of opacification of the left atrium and pulmonary veins. 20,21 Changes in degree of mitral regurgitation were assessed at two levels. First, patients who had an increase in mitral regurgitation were identified, and then those patients were separated into two groups: those with up to a l+ increase in mitral regurgitation and those with a 2+ or more increase in mitral regurgitation. The degree of valvular calcification was graded fluoroscopically from 0+ (no calcium) to 4+ (dense valvular and subvalvular calcium). The correlation between the B/A diameter ratio and the mitral valve area after the procedure was examined in a person-to-person matched group. The rationale for matching groups was to minimize the factors that may influence the outcome of mitral valve area determinations by means of either procedure. The criteria for matching were (1) sex-exact match; (2) age-within 10 years; (3) cglcifica-

1

p.0.0001

200% al p m

5 Q) 8 E ti is a

/

lnoue

Balloon

m

Double

Balloon

150% 100% p~0.0001

50% 0% w

B -loo%WA(D) MVA(G)

CO

MVG

m-PAP

m-LAP

Fig. 1. A, Comparison of absolute changesin hemodynamic values before and after percutaneousmitral valvotomy with Inoue single-balloon versus double-balloon technique. B, Comparisonof percentagechangesin hemodynamic valueswith Inoue single-balloonand double-balloon technique for percutaneous mitral valvotomy. MVA(D), Mitral valve area determined by Doppler technique; MVA(G), mitral valve area determined by Gorlin method; CO, cardiac output; MVG, mitral valve gradient; m-PAP, mean pulmonary artery pressure;m-LAP, mean left atria1 pressure.

tion-Of, exact match or 1 to 4+, match within l+; and (4) mitral valve area before valvotomy-within 0.15 cm2. Analysis of data. The chi-squaretest wasusedto determine whether optimal results and increases in mitral regurgitation were associatedwith the balloon techniques. Hemodynamicvaluesand mitral valve area (determinedby both the Gorlin and Doppler methods) were analyzed by both the Student’s t test and Wilcoxon rank-sum test. Results were expressedas mean f SD. A p value ~0.05 was consideredstatistically significant. RESULTS Hemodynamics. Mitral valve area (both Gorlin and Doppler determined), cardiac output, mitral valve

944

Ruiz et al.

American

April 1992 Heart Journal

II. Comparison of preprocedure and postprocedure hemodynamic values with the use of Inoue single-balloon and double-balloon techniques for percutaneousmitral valvotomy Table

Before Group 1 Mean k SD

Hemodynamics MVA-D (cm2) MVA-G (cm21 CO (L/min) MVG (mm Hg) m-PAP (mm Hg) m-LAP (mmHg) HR (beats/min) Doppler-determined pulmonary artery pressure; Comparison of preprocedure *p 5 0.0001. tp c 0.05.

valvotomy

MVA-D,

0.95 0.89 3.67 15.1 35 26 81

+ + k -c + + +

After Group 2 Mean k SD

0.21 0.21 0.73 5.4 12 8 18

0.94 0.88 3.85 16.4 38 27 83

f f * + i I!z k

valvotomy

Group 1 Mean -+ SD

0.22 0.24 1.02 6.7 13t 7 18

1.85 1.84 4.26 5.4 28 17 81

* ? -t + I k +

Group 2 Mean t SD

0.31 0.38 1.02 3.1 10 7 18

2.06 + 2.41 i 5.44 i 5.2 i 295 16 I 85 i-

mitral valve area; MVA-G, Gorlin-determined mitral valve area; CO, cardiac output; MVG, mitral valve gradient: mean left atria1 pressure; HR, heart rate. and postprocedure hemodynamic values within each group: all p 5 0.0001 except for heart rate (NS).

0.55* 0.63* 1.43” 3.5 11 7 17t m-PAP,

mean

m-LAP,

III. Comparisonof hemodynamic parameters in absolute values and percentagesof changebefore and after percutaneousmitral valvotomy by meansof Inoue single-balloonand double-balloon techniques Table

Absolute

Hemodynamics MVA-D MVA-G

(cm2) (cm2)

CO (L/min) MVG (mm Hg) m-PAP (mm Hg) m-LAP (mm Hg) Abbreviations *p 5 0.0001. tp 5 0.01.

Group 1 Mean f SD 0.88 0.93 0.55 -9.5 -6 -9

+ l!z t + k 2

0.34 0.30 0.66 4.8 8 6

change

Percentage

Group 2 Mean + SD 1.13 1.53 1.58 -11.3 -9 -11

+ + + +t *

0.56* 0.61* 1.24* s.st 11t 8?

Mean

Group 1 rf- SD (5-o) 98 106 15 -62 -16 -34

f k + + * +

50 43 18 18 18 20

change

Mean

Group 2 f SD f%)

133 191 46 -67 -19 -39

zk k I? zk + k

83* 108* 38’ 22 41 27

as in Table II.

gradient, and mean pulmonary artery and left atria1 pressures were significantly improved in both groups (p I 0.0001) (Table II). Before valvotomy, hemodynamic values were not significantly different between groups except for mean pulmonary artery pressure, which was significantly higher in group 2 than in group 1 (Table II). After valvotomy, group 2 had a significantly larger mitral valve area (both Gorlin and Doppler determined) and higher cardiac output than group 1; mitral valve gradient, mean pulmonary artery pressure, and mean left atria1 pressure were not significantly different between the groups (Table II). Group 2 had a statistically higher heart rate than group 1 after valvotomy. By comparing the mean absolute increase or decrease for the variables after the procedure (Table III), we found that in group 2 the increases in mitral valve area (both Gorlin and Doppler determined) and cardiac output and the decreases in mitral valve gra-

dient, mean pulmonary artery pressure, and mean left atria1 pressure were statistically significant compared with group 1. The difference in heart rate was not significant (Fig. 1, A). Compared as a percentage increase from before to after the procedure (Table III), the increases in mitral valve area (both Gorlin and Doppler determined) and cardiac output were significantly higher in group 2 than in group 1 (Fig. 1, B). With the Gorlin method for measuring mitral valve area, 76% of patients in group 1 and 93 % of patients in group 2 had optimal results (p I 0.0001) (Fig. 2). Complications. Both techniques resulted in major complications and death (Table IV). The procedure was aborted in two patients (2.4 %) in group 1 and three (0.9 % ) in group 2 because the balloon could not cross the valve or could not be inflated. The incidence of left-to-right shunt was higher (p < 0.05) in group 2 than in group 1 as shown by angiography. However,

volume Number

123 4, Part 1

Inoue versus double-balloon

Table IV. Comparison of complications with the use of In-

Comr3arison

oue single-balloon and double-balloon techniques for percutaneous mitral valvotomy Complications Unsuccessful procedure Increase in MR zzlf >2+

Emergency surgery MR LV perforation Tamponade Left-to-right shunt Qp/Qs > 1.5:1 CVAITIA Death

Inoue single balloon 2 (2.4%)

mitral

valvotomy

945

of Otdimal Results

lnoue Balloon

~8.

Double Balloon

Double balloon 3 (0.9%)

148 (46 % ) 13 (4%)*

44 (52%) 16 (19%)

76%2 (2.4%) 0

l&2%) 5 (5%)

46 8 3 4

1(1.2%) 1(1.2%) 1(1.2%)

MR, Mitral regurgitation; LV, left ventricular; dent; TIA, transient ischemic attack. *p _c 0.001. tp 5 0.05.

p < 0.001

4 (1.2%) 6 (1.9%) 2 (0.6%)

CVA,

0 0

(14%)t (2.5%) (0.9%) (1.2%)

cerebrovascular

Optimal Results Suboptimal Results

Fig. 2. Percentage of patients with optimal results as determined by Gorlin method. acci-

the rate of left-to-right shunt with QplQs >1.5:1 was not significantly different between the groups. In group 1,52 % of the patients had at least a l+ increase in mitral regurgitation after valvotomy and in group 2, 46% had at least a l+ increase (NS). Among patients who had an increase in mitral regurgitation, 36% of those in group 1 and 9% in group 2 had a 2+ or more increase (p < 0.001) (Fig. 3). Emergency surgery was required in approximately 3.6% of patients in both groups. Left ventricular perforation was induced only by the double-balloon technique. Tamponade developed during the procedure in both groups. Two patients (2.4%) in group 1 and four (1.2 % ) in group 2 required mitral valve replacement or repair because of severe mitral regurgitation. Death was considered to be procedure related if a patient died within 6 weeks after valvotomy. There were five procedure-related deaths: one (1.2 % ) in group 1 and four (1.2 % ) in group 2. Clinical evaluation. After percutaneous mitral valvotomy, the groups did not differ with regard to New York Heart Association functional class: 98.8% in group 1 and 98.1% in group 2 were in class I or II. Balloon diameter to mitral valve annulus ratio. The relationship between the B/A diameter ratio and the mitral valve area after valvotomy was significantly correlated (r = 0.62, p 5 0.0001). However, because postprocedure mitral valve area may depend on preprocedure mitral valve area, further analysis was performed to find the relationship for the absolute increase in mitral valve area and B/A diameter ratio. Fig. 4 shows that the larger the B/A diameter ratio, the greater the increase in mitral valve area. Mean

B/A diameter ratio was 45% larger in group 2 than in group 1 (1.16 -t 0.13 vs 0.80 & 0.10, p I O.OOOl), and the mean increase in mitral valve area was 65 % greater in group 2 than in group 1. DISCUSSION

This nonrandomized comparative study, the largest to our knowledge done for percutaneous mitral valvotomy, shows favorable hemodynamic results and symptomatic improvement with the use of either balloon technique, as reported previously.1-16 The incidence of increase in mitral regurgitation was about the same but more severe in the group in which the Inoue single-balloon technique was used. The rate of left ventricular perforation created by the double-balloon technique could be reduced by improving the design of the balloon catheter, for example, by using a pigtail balloon catheter.22 The greater mitral valve area by the Gorlin formula may be largely dependent on a higher cardiac output. A larger percentage of patients in group 2 had left-to-right shunts, which may explain the higher cardiac output. However, Ribeiro et all6 showed that double-balloon valvotomy yields a larger mitral valve area independent of atria1 septal defect. Palacios et a1.i8 also found in a study of 100 consecutive patients that the double-balloon technique yielded a significantly greater mitral valve area immediately after valvotomy than the single-balloon method. In our study the larger mitral valve area achieved with the double-balloon technique is corroborated by both Gorlin and Doppler calculations. Use of two balloons permits safe 25 % oversizing of the annular diameter, because the area occupied by the two expanded balloons does not exceed the val-

April

946

Ruiz et al.

American

Increase !52k&&m No change

m

Hearl

1992

Journal

in MR Double Balloon

48%

9% 2-4+

3 U

42%

UP l+

increase in MR vs. no change: p 0.3 MR up l* vs. up 2-4+: p t 0.001 n

Fig. 3. Percentage of patients with increase in mitral regurgitation tral valvotomy.

.-

A lnoue Balloon

. Double Balloon

, *

-.

.

:- . .

. .

.

EU.”

2

’

-

A

AA-

.

r Y

n n

0.66. p -0.46

n l

0.0001 1.79x

0’“““““““““““““““““““““1”““’ .5 .6 .7 .8 .Q 1.0 1.1 1.2 1.3 1.4 1.5 B/A Diameter Ratio Fig. 4. Relationship betweenincreasein mitral valve area (Gorlin method) to balloon/anulus (B/A) diameter ratio in person-to-personmatched group (seetext).

vuiar orifice area.23s24When two balloons are inflated simultaneously, tension applied to the plane of the mitral commissures is twice the tension applied vertically according to La Place’s law. Hence there is more effective splitting of the fused commissures and less risk of rupturing or tearing of the leaflets, which are the weakest structures of the mitral valve apparatus; consequently there is less risk of creating severe mitral regurgitation and achieving a larger mitral valve area.

(MR) after percutaneous balloon mi-

Chen et a1.13found no advantage to the doubleballoon technique. Although their trial was not randomized either, in their series of 94 patients, 73 of whom underwent Inoue single-balloon valvotomy and 21 of whom underwent double-balloon valvotomy, the success rate was higher and the complication rate lower with the single-balloon technique. Limitations of the study Measurement of mitral valve area. Both the Gorlin and Doppler pressure half-time calculations for estimating mitral valve area have limitations that may increase after valvotomy. For example, changes in atria1 and ventricular compliance after the procedure can alter the pressure half-time value without changing the “true” valve area; changes in flow from the atria1 septal defect after valvotomy may alter the Gorlin formula estimation of “true” valve area; and changes in mitral or tricuspid regurgitation can have a similar effect. Although planimetry of two-dimensional images of the mitral valve area is not affected by these factors, it was performed only in a subset of our patients. Optimal results. “Optimal results” according to the definition used may not be truly optimal in every case. For example, a final mitral valve area of 1.5 cm2 that represents a 50 % increase over a prevalvotomy mitral valve area of 1.0 cm2 in a large adult is definitely not an optimal result. In addition, the definition does not consider complications. A patient with a final mitral valve area of 2.5 cm2 but with significantly increased mitral regurgitation (2+ or more) may not have results that could be considered optimal. Sample size and learning curve. Although both groups had large sample sizes, group 1 had a relatively small number of patients (N = 85) compared

Volume Number

123 4, Part 1

with group 2 (N = 322). The higher rate of severe increase in mitral regurgitation created by the Inoue single-balloon technique (group 1) may be explained in part by the learning curve. Inoue single-balloon valvotomy was begun in our study almost 1.5 years after mitral valvotomy had been performed in approximately 150 patients by means of the doubleballoon technique. To minimize the learning curve effect on the results of the comparison, we included all patients in whom double-balloon valvotomy was performed. Therefore the results in group 2 (doubleballoon) also included the learning curve effect. Echocardiographic evaluationof mitral valvemorphology. The description of mitral valve morphology and grading by echocardiography was first reported in February 198B2; because many of our patients were studied before then, we do not have the data on mitral valve morphology by echocardiography in these patients. Conclusions. Significant hemodynamic and symptomatic improvements are achieved with either Inoue single-balloon or double-balloon mitral valvotomy; however, the improvements in hemodynamic values and mitral valve area appear to be greater immediately after valvotomy by means of the doubleballoon technique. Because this was a nonrandomized trial, long-term follow-up studies will be needed to determine whether or not the immediate hemodynamic superiority of the double-balloon technique is clinically important. REFERENCES

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;87:39440‘2. 2. Abascal VM, Wilkins GT, Choong CY, Block PC, Palacios IF, Weyman AE. Mitral regurgitation after percutaneous balloon mitral valvuloplasty in adults: evaluation by pulsed Doppler echocardioeranhv. J Am Co11 Cardiol 1988:11:257-63. 3. Chen C, Lo Z: Huang Z, Inoue K, Cheng TO. Percutaneous transseptal balloon mitral valvuloplasty: the Chinese experiencein 30 patients. AM HEART J 1990;115:937-47. 4. Herrmann HC, Kleaveland JP, Hill JA, et al, for the M-Heart group. The M-Heart Percutaneous Balloon Mitral Valvuloplasty Registry. Initial results and early follow-up. J Am Co11 Cardiol 1990;15:1221-6. 5. Herrmann HC, Wilkins GT, Abascal VM, Weyman AE, Block PC, Palacios IF. Percutaneous balloon mitral valvotomy for patients with mitral stenosis. J Thorac Cardiovasc Surg 1988;96:33-8. 6. Lock JE, Khalilullah M, Shrivastava S, Bahl V, Keane JF. Percutaneous catheter commissurotomy in rheumatic mitral stenosis. N Engl J Med 1985;313:1515-8.

Inoue versus double-balloon mitral valvotomy

947

7. McKay RG, Lock JE, Safian RD, et al. Balloon dilation of mitral stenosis in adult patients: postmortem and percutaneous mitral valvuloplasty studies. J Am Co11 Cardiol1987;9:723-31. 8. Palacios IF, Block PC. Percutaneous mitral balloon valvotomy (PMV): update of immediate results and follow-up [Abstract]. Circulation 1989;81(suppl II):II-489. 9. Palacios I, Block PC, Brandi S, et al. Percutaneous balloon valvotomy for patients with severe mitral stenosis. Circulation 1987;75:778-84. 10. Rediker DE, Block PC, Abascal VM, Palacios IF. Mitral balloon valvuloplasty for mitral restenosis after surgical commissurotomy. J Am Co11 Cardiol 1988;11:252-6. 11. Wilkins GT, Weyman AE, Abascal VM, Block PC, Palacios IF. Percutaneous balloon dilatation of the mitral valve: an analysis of echocardiographic variables related to outcome and the mechanism of dilatation. Br Heart J 1988;60:299-308. 12. Ruiz CE, Allen JW, Lau FYK. Percutaneous double balloon valvotomy for severe rheumatic mitral stenosis. Am J Cardiol 1990;65:473-7. 13. Chen CR, Huang ZD, Lo ZX, Cheng TO. Comparison of single rubber-nylon balloon and double polyethylene balloon valvuloplasty in 94 patients with rheumatic mitral stenosis. AM

HEART-J 199O;i19:102-11. 14. Al Zaibae M. Ribeiro PA. Al Kasab S. Al Faeih MR. Percuta,

15.

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23.

24.

”

neous doible-balloon mitral valvotomy for rheumatic mitralvalve stenosis. Lancet 1986,1:757-61. McKay CR, Kawanishi DT, Kotlewski A, et al. Improvement in exercise capacity and exercise hemodynamics 3 months after double-balloon, catheter balloon valvuloplasty treatment of patients with symptomatic mitral stenosis. Circulation 1988;77:1013-21. Ribeiro PA, Zaibag M, Rajendran V, et al. Mechanism of mitral valve area increase by in vitro single and double balloon mitral valvotomy. Am J Cardiol 198862:264-g. Al Zaibag M, Ribeiro PA, Al Kasab S, et al. One-year follow-up after percutaneous double balloon mitral valvotomy. Am J Cardiol 1989;63:126-7. Palacios IF, Block PC, Wilkins GT, Weyman AE. Follow-up of patients undergoing percutaneous mitral balloon valvotomy. Analysis of factors determining restenosis. Circulation 1989;79:573-9. Abascal VM, Wilkins GT, O’Shea JP, et al. Prediction of successful outcome in 130 patients undergoing percutaneous balloon mitral valvotomy. Circulation 1990;82:448-56. Grossman W. Profiles in valvular heart disease. In: Grossman W, ed. Cardiac catheterization and angiography. 3rd ed. Philadelphia: Lea & Febiger, 1985:359-81. Sellers RD, Levy MJ, Amplatz K, Lillehei CW. Left retrograde cardioangiography in acquired cardiac disease. Technique, indications and interpretation in 700 cases. Am J Cardiol 1964;14:437-47. Berland J, Gamra H, Rocha P, Mechmeche R, Lefevre E, Criber A, Letac B. Mitral valvuloplasty: improvement in safety and efficacy by using the new pigtail balloons [Abstract]. Circulation 1988:78(suppl IIl:II-490. Ruiz CE, Allen JW, Kaiser PJ;Lau FYK. Percutaneous double balloon valvotomy for patients with severe mitral stenosis. In: Vogel JHK, King III SB, eds. Interventional cardiology: Future directions. St. Louis; CV Mosby, 1989:219-31. Ruiz CE, Boltwood Jr CM, Lau FYK. Percutaneous double balloon aortic valvuloplasty in an adult patient with calcific aortic stenosis and a Bjork-Shiley prosthetic mitral valve. Cathet Cardiovasc Diagn 1988;15:265-70.