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Percutaneous mitral balloon dilatation by a new sequential single- and double-balloon technique
American Founded
November
CLINICAL
Heart
Journal
in 1925
1988 Volume 116, Number 5, Part 1
INVESTIGATIONS
Percutaneous mitral balloon dilatation sequential single- and doubte-balloon
by a n&w technique
Percutaneous balloon valvotomy by means of a new sequential single- and double-balloon dilatation procedure was performed in 23 patients (aged 13 to 53 years) with severe rheumatic mitral stenosis. The dllatatZon procedure was lnMally performed with a small balloon to primarily dilate the stenotic valve for easier passage of a second balloon catheter and to make the procedure tolerable for severely ill patients; the procedure was then followed by two b&Moons to further increase the mitral valve area (MVA) for effective dilatation of the stenotic mitral orifice. The dllatatlon was successful in all patients; the mitral valve pressure gradient decreased from 19 rt 6 to 5 2 2 mm Hg, the cardiac output increased from 4.0 + 0.5 to 5.2 + 0.6 L/min, and the MVA increased from 0.8 + 0.2 to 1.9 f 0.4 cm2 (p < 0.01 each). The MVA after dilatation was relative to the effective balloon dilation diameter selected (r = 0.57; p < 0.01). A small atrial septal defect was observed In 3 of 23 patients immediately after the dilatation procedure. Mild mitral regurgitation was produced In 3 of 23 patients by the dllatatlon. We conclude that the sequential single- and double-balloon dilatation procedure can effectively increase the MVA and improve hemodynamlcs in severe mitral stenosis and that the larger effective balloon diameter of 24.8 mm or more (12 ? 18 mm of two balloons) is necessary for effective dilatation. (AM HEART J lg88;116:1161.)
Chunguang Chen, MD, Yipo Wang, MD, Duan Qing, MD, Yushan Lin, MD, and Yufu Lan, MD. Fuzhou, The People’s Republic of China
Preliminary experience with percutaneous mitral balloon dilatation (PMBD) is encouraging, and in many instances PMBD has made it possible to avoid thoracotomy, cardiopulmonary bypass, or both.1-g In developing countries without adequate cardiac surgical resources PMBD may provide an attractive alternative to surgical commissurotomy. Recognizing the importance of introducing PMBD to the population with a high prevalence of rheumatic heart disease in The People’s Republic of China, we began to study the technique of PMBD in 1986 after successful PMBD with a single-balloon technique was reported by Inoue et a1.2 in 1984 and Lock et al.’ in 1985. However, technical difficulties were someFrom the Cardiovascular Center and Union Hospital, Fujian Medical College. Supported by grant No. 87 from the Fujian Scientific and Technological Committee. Received for publication Feb. 9, 1988; revision accepted June 24, 1988. Reprint requests: Chunguang Chen, MD, Cardiovascular Center, Fujian Medical College, Jiaotong Road, Fuzhou/Fujian, The People’s Republic Of China.
times encountered in manuvering a large balloon catheter with redundant balloon material over a severely stenotic mitral orifice, the atria1 septum, and even the femoral vessels. Zaibag et al,3 McKay et al.,4 and Mullins et al.9 reported on the usefulness of a double-balloon technique for dilatation of mitral stenosis. These investigators believed that the double-balloon technique had the advantage of easy manipulation of balloon catheters across the stenotic orifice and produced a larger mitral valve area. By means of a new sequential dilatation technique, PMBD was performed in 23 patients with severe mitral stenosis admitted to the cardiovascular center of Fujian Medical College between April and December, 1987. The sequential dilatation technique modifies the original single and doubleballoon techniques by combining both techniques for PMBD in a dilatation procedure. Initially a relatively small balloon catheter is introduced into the mitral valve orifice and the stenosis is partially dilated. A second balloon catheter is then inserted into the mitral valve, and both balloon catheters are 1161
1162
Chen et al.
inflated simultaneously for maximum dilatation. In this study the immediate results of hemodynamic and clinical improvement and the technical characteristics of the sequential single- and double-balloon dilatation technique are described. METHODS Patients. The study population consisted of 23 patients with mitral stenosis with symptoms severe enough to require surgical valvotomy (Table I). There were 14 females and nine males with a mean age of 31 + 12 (range 13 to 53) years (Table II). All patients had exertional dyspnea, and 7 of 23 had a history of acute pulmonary edema. Five of 23 patients were in chronic atria1 fibrillation. Two of 23 patients had a past history of cerebral arterial embolization more than 6 months before PMBD. Two patients had restenosis after previous surgical mitral commissurotomy. Sixteen patients were in New York Heart Association (NYHA) functional class III, four were in NYHA class II, and three were in NYHA class IV. Two-dimensional echocardiography was performed in all patients, 1 day before valvuloplasty; no patients with a severely calcific and stiff mitral valve or left atria1 thrombus were included in the study. Cardiac catheterization. Right- and left-sided heart catheterization was performed by means of a percutaneous technique via the left femoral vessels. After pulmonary pressure, right ventricular pressure, aortic pressure, left ventricular pressure, pulmonary capillary wedge pressure,andcardiacoutputwererecordedbytheFickprinciple, transseptal left-sided heart catheterization was performed with a 8F Mullins transseptal sheath, dilator, and Brockenbrough needle via the right femoral vein. Simultaneous pressure tracings from the left atrium and left ventricle were recorded to document mitral valve stenosis and determine the pressure gradient across the mitral valve. After complete hemodynamic measurements were obtained tine left ventriculography was performed with a retrograde pigtail catheter in the left ventricle for assessment of mitral regurgitation. The severity of mitral regurgitation was graded semiquantitatively from classes I to IV.‘O Percutaneous mitral balloon catheter valvotomy. Immediately after ventriculography the PMBD procedure was begun. Two guide wires (0.035 or 0.038 inch) were inserted through the Mullins transseptal sheath into the left atrium. After withdrawing the sheath and leaving the guide wires in the left atrium, a 7F Critikon large-lumen balloon-tipped pulmonary artery catheter (Critikon, Inc., Tampa, Fla.) (able to accommodate a 0.038 inch guide wire) was introduced over a guide wire into the left atrium and then across the mitral valve in the left ventricle. After the guide wire was positioned near the left ventricular apex and well coiled in the left ventricle, the Swan-Ganz catheter was withdrawn leaving the guide wire coiled in the loft rron+-;n’r ._A._*i. K’itli the same procedure a second guide wire was inserted into the left ventricle. A deflated 10 to 18 mm dilatation balloon catheter (Mansfield Scientific Inc., Mansfield, Mass.) was advanced along one guide wire
American
November 1988 Heart Journal
and positioned across the mitral valve. The balloon was inflated to 4 atmospheres for 6 to 11 seconds with 1:l saline solution and 76% Urografin. The procedure was repeated until the waist of the balloon disappeared and/or the inflation balloon moved with systole and diastole, indicating achievement of an increase mitral orifice with the corresponding balloon catheter. After hemodynamic measurements were obtained by Swan-Ganz catheter in the pulmonary position and pigtail catheter in the left ventricle, a second 10 to 15 mm balloon catheter was introduced along the other guide wire and positioned along side the prepositioned balloon catheter across the mitral valve. The two balloons were inflated simultaneously for 6 to 15 seconds. The inflation was repeated until the dilatation was considered satisfactory according to the following signs: (I) no waist was observed on the inflated balloon; (2) the inflated balloon moved with ventricular systolic and diastolic phases into the left atrium or left ventricle; and (2) a significant decrease in left atria1 pressure was obtained. After PMBD the balloon catheters were removed and the hemodynamic measurements were repeated. Cine left ventriculography was performed in the same projection as before PMBD. Patients were then transferred to an intensive unit and monitored for 24 hours. Echocardiography was performed to exclude pericardial effusion and tamponade. All PMBD procedures were performed without surgical standby. Statistical analysis. All values are expressed as mean -t 1 standard deviation. Hemodynamic parameters before and after PMBD were compared by Student’s t test. The effective balloon dilation diameters were correlated with mitral valve areas after PMBD by linear regression analysis. A p value of 0.05 or less was considered statistically significant. RESULTS Methodologic characteristics. In our first two patients with a mitral valve area of 0.6 and 0.5 cm2, we used a 25 mm balloon catheter to perform the single-balloon method of Lock et al.’ Although the catheter was introduced through the atria1 septum, the balloon catheter failed to cross through the mitral valve, preventing successful inflation and dilatation of the valve. We then used the doubleballoon technique described by McKay et a1.7 The first smaller balloon catheter with an inflation diameter of 15 or 18 mm was successfully maneuvered across the mitral valve and into the left ventricle. The second balloon catheter was introduced along another guide wire; however, it failed to pass across the mitral valve. We decided to dilate with the first balloon placed across the mitral valve, and this procedure was repeated until hemodynamic measurements of successful dilatation of the stenotic valve were observed. The second balloon was then inserted without difficulty.
Volume Number
116 5, Part 1
Percutaneous
mitral
balloon
dilatation
1163
I. Hemodynamics before and after PMBD
Table
Mean pressures (mm Hg) co (Llmin) B
A
B
A
1
3.2
5.9
33
26
90
91
20
11
18
2
5.5 6.0 5.0
48 21 30
35 18 20
85
3 4
4.0 4.5 3.8
84 95
41 17 24
14 10 12
38 13
5 6 7
4.0 4.2 4.1
5.8 5.1 5.9
16 30 15
22 24
10 IO
6 4 4
8 9 10
3.9 4.5 4.2
4.0 4.8 5.1
25 46 26 22
14 18
20 18 16
10 6
11 12 13
4.3 3.4 4.4 4.2
5.9 5.0 5.0
14 15 16
4.3 3.7
17 18 19
4.3 3.5 3.4
20 21 22
3.6 5.2 3.7 5.1
23
Mean SD
4.0 0.5
PA
5.1 5.1 6.3 5.1 3.8 4.6 4.4 6.3 4.8 5.9 5.2 0.6
24 33
15 12 25
22 32 32 54
18 15 18 38
54 36
38 28
60 25 30
53 18 24
55 25 21 65
50 21 12 47 25
34 14
CO = Cardiac output; PA = pulmonary artery pressure: valve area; B = before; A = after PMBD: SD = standard
12 = aortic deviation.
A0
90 93 88 78 80 70 92
A
98 90 76 75 82
__-~ R
LA
MVA
A0 ___-B
Patient NO.
MVG A
80 86 90 79 84
85 75 69
23 17
6 s 8
88 86 99 98
18 22 18 29
10 8 11 14
76 80 90
78 83 82
17 32 17
80 68 90
93 84 92
80 82 83 7
82 84 85 8
26 23 26 17
10 10 13 12 9 14 11
33 23 6
14 10 3
70
pressure:
After these two cases the procedure for dilatation was always the same starting with the first singleballoon dilatation followed by double-balloon dilatation as described previously. With this sequential dilatation procedure passing of the balloon catheter into the left ventricle was uneventful, and the stenotic mitral valve was successfully dilated in all patients. After the first step of the dilatation procedure it was noted that the guide wires placed in the left ventricle produced fewer ventricular premature contractions, the mitral valve pressure gradient decreased, and the mitral valve area increased (Table III). Patients were then able to tolerate the additional dilatation procedure without difficulty. Always a new waist appeared on the balloons during simultaneous inflation of the two side-by-side balloons across the mitral valve at the beginning of the second step of dilatation, and after several dilatations the waist disappeared again, indicating a further increase in the size of the mitral orifice. The total duration of the procedure averaged 2.5 (range 2 to 3.5) hours, which included all of the pre-
LA = left
atria1
pressure:
B
B
A
4
0.6
8 4
0.5 1.3 0.8
2.2 1.7
6 3 2
20 11
5 2
19 19 15
8 4 6 5
0.6 0.8 0.7
3 5 6
0.5 0.6 0.7
8 6 7 4
0.6 0.6 0.8 0.7
9 5
0.9 0.8
2
0.2
17 23 20 18 26 19 6 = trammitral
valve
2.4 1.8 2.6
0.8 0.7 0.9
18 16 11 12
26 16 29 15
MVG
A
(cm’)
1.7 2.5
0.9 1.1
1.8 1.8 2.3
0.8 1.3 0.3
gradient;
2.1 1.6 1.9 1.7 1.4 1.8 1.4 1.3 1.6 1.6 2.1 2.2 1.9 1.9 0.4 MVA
= mitral
and post-PMBD catheterization procedures. All patients tolerated the procedure well. No medica tion was used for prevention of acute heart failure during the procedure, and no dyspnea or acute pulmonary edema occurred during the procedure. General clinical information. No artery embolization after PMBD was observed in the patients studied. At discharge all patients had improved cardiac function. Fourteen of 23 patients (60%) were in NYHA class I and 9 (40%) were in NYHA class 11. All patients except one were ambulatory on the second day after the PMBD procedure. One patient had acute pericardial tamponade documented by two-dimensional echocardiography. Pericardiocentesis was performed in one patient, and 106 ml bloodlike fluid was aspirated. The patient was then stable and mobile on the third day. All patients except one were discharged 2 weeks after the PMBD procedure. One patient had septicemia on the fifth day after the PMBD procedure and was treated with antibiotics for 4 weeks. This patient was discharged by the sixth week.
1164
Chen et al.
Table
II. Factors
Amerlcsn
relative
to effects of PMBD
Age h-1
MVGR (mm &I
Patient No.
MVA (cm’)
BD (mm)
EBD (mm)
B
50 32
14 30
2.2 1.7
18 & 12 15 +- 12
24.8 22.1
AF
3 4 5 6 7 8 9
9 8 14 14 10 8 10 15 9 11 15 9 21 23 24 9 9 17 13
2.4 1.8 2.6 1.7 2.5 1.8 1.8 2.3 2.1 1.6 1.9 1.7 1.4 1.8 1.4 1.3 1.6 1.6 2.1
15 15 18 18 15 15 15 18 15 12 18 15 15 15 12 10 12 15 18
12 18 12 12 18 18 12 12 18 12 12 18 12 18 12 10 12 12 15
22.1 27.1 24.8 19.7 27.1 27.1 22.1 24.8 27.1 19.7 24.8 27.1 22.1 27.1 19.7 16.3 19.7 22.1 27.1
MI-I MI-I
16 17 18 19 20 21
16 26 26 36 34 19 21 18 32 50 29 42 15 13 38 47 53 37 33
22 23
38 25
14 17
2.2 1.9
18 +- 15 18 f 15
27.1 27.1
10 11 12 13 14
15
MVGR = Transmitral valve gradient reduction by PMBD; MVA = mitral valve EBD = effective balloon dilation diameter: AF = atria1 fibrillation; MI-I = mild mitral septal defect
Hemodynamic changes by PMBD. Data are shown in Table I. All patients had severe mitral stenosis. Before PMBD the mitral valve area calculated by Go&n’s formula was 0.8 k 0.2 cm2. It increased to 1.9 +- 0.4 cm2 after PMBD (p < 0.01). The pressure gradient over the mitral valve decreased from 19 +6 to 5 +- 2 mm Hg by PMBD (p < 0.01). There was a significant increase in the cardiac output and a significant decrease in left atrial and pulmonary pressure after PMBD (Table I). The aortic pressure did not change significantly after PMBD (Table I). Effective balloon tion. The selection
dilation
size and effects
of dilata-
of balloon diameter was not based on the size of the mitral anulus in our study. The randomly selected balloon size in the present study varied from 10 to 18 mm. The effective balloon dilation diameter of the two balloons was calculated according to the equation of Yeager.” Linear regression analysis showed a significant relationship between the effective balloon dilation diameter and the
Associated abnormalities
1 2
* f f k k * + +f * +f -+ + + * f f f
mitral
vralxre ~~00 -c+n_.__- -*“II
P&fBI);
ijie
correiation
coefficient (r) was 0.57 (p < 0.01; (Fig. 1). There was no significant correlation between the effective balloon dilation diameters and reduction in the pres-
November t988 Heart Journal
A MI-I
-
-
MI-I MI-I -
AF
-
AF -
MI-I
-
MI-I -
SMC
PT
-
MI-I, ASD Septicemia AF
-
-
AF
AF SMC, AF
AF
-
MI-I
-
ASD
ASD -
area after PMBD; BD = balloon diameters used for dilatation; regurgitation; SMC = surgical mitral commissurotomy; ASD = atrial
sure gradient (Table II). The magnitude of the pressure gradient reduction was primarily related to the pressure gradient before PMBD, with a correlation coefficient of 0.64 (p < 0.01). Age and mitral valve calcification were not related to the mitral valve area after PMBD. Atrial septaI defects were observed in three patients immediately after PMBD, with pulmonaryto-systemic flow ratios of 1.3: 1, 1.5: 1, and 1.6: 1, respectively. Residual atrial septal defects were not related to the balloon diameter used (Table II). Two patients had mild mitral regurgitation (grade I) before PMBD, and the regurgitation was not changed after PMBD. The new mitral regurgitation with grade I was produced in three patients by PMBD. It occurred in relatively old patients aged 50 years or more (Table II). These three patients all had moderate mitral valve calcification, and one of three patients had previously undergone surgical mitral commissurotomy (Table II). DISCUSSION
The results of the present study show that percutaneous balloon mitral valvotomy is a safe and effective method for increasing stenotic mitral areas
VOlUrn~ 116 Number 6. Part 1
Percutaneous
mitral
balloon
dilatation
1165
.
8’
.
A’
l .
.
. . .
iI:-
.
%4 1 23 !! f .
.
.
.. .. .
.
I+
12
r - 0.51
I
I
I
I
I
I
I
I
14
16
18
20
22
24
26
28
effdve
Fia. 1. Correlation between Y = 5.3 X +33.7 (mm).
. ..
. . .
effective
BBllam
balloon
mlatial
dilation
and relieving symptomatic rheumatic mitral stenosis. The mitral valve area after PMBD was significantly related to the effective balloon dilation diameter. We describe our experience with a new modified technique of sequential dilatation by first using a relatively small balloon for preliminary dilatation and then adding another balloon catheter, which enables both easy manipulation of the balloon catheters across the tight mitral valve and effective increase of the mitral valve area. Rationale of the sequential dilatatlon technique. A balloon catheter with an inflated balloon diameter of 23 to 25 mm needs a venous sheath of 14F (4.6 mm) for introduction into the blood vessel with the balloon completely deflated and balloon material properly wrapped and compressed along the catheter sheath.3x lo It is more difficult to introduce a balloon catheter with redundant balloon material within the cardiac cavity because the balloon material may not be as well wrapped and compressed as it is in the venous sheath after it advances through the sheath.g Usually a dilatation catheter with a round balloon diameter of 8 to 10 mm is necessary to dilate the atrial septum so that a single balloon catheter of 25 mm can be advanced through the septum into the left ventricle during the PMBD procedure.*.4,” Unfortunately the pathologic shape of the rheumat-
DiMmta
diameters
30
(I)
and mitral
valve areas after PMBD.
Table III. Hemodynamics after the first and second of the dilatation procedure MVG (mm Hd
DilQtOtiOt2
First step Second step MVG = Mitral tral valve area.
valve
co (Llmin)
11 -t 5 5*+2 pressure
gradient;
4.6 5.2 CO
-+ -+
0.4 0.6
= cardiac
steps
MVA (cm3 1.3 1.9
* *
output;MVA
_
0.3 0.4 = mi-
ic mitral stenosis resembles a buttonhole at autopsy12 and in the live beating heart the mitral valve orifice demonstrated by two-dimensional echocardiography has an oval shape that is longer in its horizontal than its vertical dimension in most patients with mitral stenosis.‘” Therefore it is not surprising that in severe mitral stenosis with a valve area less than 0.8 cm2 and a diameter less than 10 mm the operator encounters difficulty in maneuvering a large balloon catheter (25 mm) through the mitral orifice into the left ventricle even if it passes through the atria1 septum. With the double-balloon technique each relatively small balloon catheter is more compliant and appears easier to maneuver transseptally and across the mitral valve.7sg The two side-by-side balloon catheters take advantage of the
1166
Chen et al.
oval shape of the stenotic mitral valve. However, in very irregular shaped and very small mitral orifices (<0.6 cm2) difficulty may still be encountered in advancing the second balloon catheter into its proper position across the mitral valve. This has been our experience. The sequential dilatation technique applied in the present study includes two steps to enlarge the stenotic mitral valve orifice. The first step of preliminary dilatation by a dilatation catheter of 15 to 18 mm inflated balloon diameter increases the mitral valve area significantly. This makes the second step easier in that the second balloon catheter can be advanced across the mitral valve without difficulty. The preliminary improvement in hemodynamics (Table III) enables the patients to tolerate better the second step of the dilatation procedure, although the mitral valve area (1.3 + 0.3 cm2) after the first step of the dilatation procedure, which uses a single balloon, was not adequate for satisfactory improvement of cardiac function. The purpose of the second step of the dilatation procedure, which uses the double balloon, is to further increase the mitral valve area for adequate improvement of hemodynamics and cardiac function by PMBD, this is also the purpose of the PMBD used for management of mitral stenosis. In the present study the mitral valve area of 1.9 rt_ 0.4 cm2 after PMBD appears larger than that in the study performed by McKay et aLa In their study PMBD was performed by the single-balloon technique in most patients, and the mitral valve area after PMBD was 1.6 + 0.4 cm*. Although precise comparison of the two studies is difficult, one of the important reasons may be the larger effective balloon dilation diameter by the second step of the double-balloon dilatation in our sequential procedure compared to the single-balloon dilatation technique used by McKay et a1.8 We have demonstrated that the mitral valve area after PMBD was significantly related to the effective balloon dilation diameter and have shown that the selection of two combined balloon catheters of large effective balloon dilation diameter not less than 24.8 mm (12 + 18 mm or 15 +- 15 mm) should be considered for effectively increasing the mitral area (Fig. 1). However, greatly variable results by large effective balloon dilation diameter ~24.8 mm suggest that other factors are also responsible for the efficacy of PMBD, such as the pathologic type of rheumatic mitral stenosis (valvular and/or aubvalvular) and tne size of the mitral anulus.3z 7*l*, l4 The time needed for the sequential dilatation procedure averaged 2.5 hours and was less than the
American
November 1998 Heart Journal
4.0 hours in the study by McKay et al7 with the use of a double-balloon technique. However, the duration of the procedure may be significantly related to the learning curve. According to our experience it takes more time to perform PMBD at the beginning; we now need less than 2 hours to complete a sequential dilatation procedure including pre- and post-PMBD catheterization, which is comparable to the time needed for the single-balloon technique reported by Palacios et a1.s Complications of the sequential procedure. The potential complications of PMBD include mitral regurgitation, thromboembolic episodes, pericardial effusion or tamponade, and atria1 septal defect produced by transseptal left cardiac catheterization as reported by several groups with the use of the single-balloon or the double-balloon technique.1-g A mild increase in mitral regurgitation was produced in 13% of 23 patients with PMBD by means of the present sequential dilatation procedure and appeared in less than 29% of the 78 patients summarized from studies published in 1987.5g7-g The cause of this discrepancy is not clear. Palacios et a1.5 showed that mitral regurgitation was not related to the balloon size selected. Results of the present study suggest that older patients with calcific valves may be more prone to develop mitral regurgitation. It is yet to be determined whether a gradual increase in the size of the mitral valve by the sequential dilatation procedure may contribute to fewer mitral regurgitations. Whether more severe atria1 septal defects will develop with the sequential dilatation procedure by using the same septal puncture for introducing the two balloon catheters is uncertain. Atria1 septal defects were detected in 3 (13 % ) of 23 patients with small left-to-right shunts and were hemodynamically insignificant. This is comparable to the results by others who used either the single-balloon technique or two separate septal punctures with the doubleballoon technique.3* 7*s Indications for sequential balloon dilatation. Immediate results achieved by our sequential balloon dilatation procedure, the single-balloon technique, and the double-balloon technique of others for mitral stenosis are comparable to those of surgical commissurotomy.l-s~ I4 Although the long-term results of PMBD are still unknown, good results may be expected from the long-term results of surgical commissurotomy.14 This is because the mechanism of opening mitral valve stenosis by PMBD is no different from that of closed surgical commissurotomy.6s 12-14Thus PMBD is at least an attractive and alterative method for relief of mitral
Volume Number
116 6, Part 1
Percutaneous
stenosis if not preferable to surgical commissurotomy. Particularly in nonindustrialized countries where the prevalence of rheumatic heart disease is still relatively high12 and cardiac surgical resources are limited, PMBD may provide not only the advantage of a short hospital stay and avoidance of thoracotomy but also a therapeutic chance for patients with severe mitral stenosis who would otherwise have to wait a long time for surgery, as has been the experience at our hospital in The People’s Republic Of China. Until now there has been no comparative study dealing with the question of which balloon dilatation technique should be used. According to results of noncomparative studies with small groups of patients, the double-balloon technique provides a larger effective balloon dilation diameter, produces less arterial pressure reduction during balloon inflation, and makes it technically easier to maneuver the balloon catheters across the valve orifice; thus it may be preferable to the single-balloon technique.3j 5,7,s In severe mitral stenosis, as shown in the present study, the sequential dilatation procedure may overcome the drawbacks of the double-balloon technique with occasional failure to pass a second balloon catheter across a very tight mitral valve stenosis. Also too much time spent introducing the balloon catheters in their proper position may not be tolerated by very sick patients. Therefore the sequential dilatation procedure may be preferable in patients with severe and symptomatic mitral stenosis. However, determination of the method of choice for PMBD requires a larger number of patients for comparative and long-term studies. We thank Dr. C. R. McKay for technical suggestions double-balloon technique and Dr. M. M. Weiss for suggestions and help in preparing the manuscript.
on the critical
mitral
balloon
dilatation
1167
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Lock JE, Khalilullah M, Shrivastava S, Bahl V, Keane JF. Percutaneous catheter commissurotomy in rheumatic mitral stenosis. N Engl J Med 1985;313:1515. Inoue K, Owani T, Nakamura F, Miyamoto N. Clinical application of transvenous mitral commissurotomy by a new balloon catheter. J Thorac Cardiovasc Surg 1984;87:394. Zaibag MA, Ribeiro P, Kasab SA, Fagih MA. Percutaneous double-balloon mitral valvotomy for rheumatic mitral stenosis. Lancet 1986,1?757. McKay RG, Lock JE, Keane JF, Safian AD, Aroesty JM, Grossman W. Percutaneous mitral valvotomy in an adult patient with calcific rheumatic mitral stenosis. J Am Co11 Cardiol 1986;7:1410. Palacios I, Block PC, Brandi S, Blanc0 P, Casal H, Pulido JI, Munoz S, D’Empaire G, Ortega MA, Jacobs M, Vlahakes G. Percutaneous balloon valvotomy for patients with severe mitral stenosis. Circulation 1987;75:778. Block PC, Palacios IF, Jacobs M, Fallon J. The mechanism of successful mitral valvotomy in humans. Am J Cardiol 1987; 59:178. McKay CR, Kawanishi DT, Rahimtoola S. Catheter balloon valvuloplasty of the mitral valve in adults using a doubleballoon technique. JAMA 1987;257:1753. McKay RG, Lock JE, Safian R; Come P, Diver DJ, Bairn D, Berman RD. Warren SE. Mandell VE. Roval SD. Grossman W. Balloon ‘dilatation of mitral stenosis in adult patients: postmortem and percutaneous mitral valvuloplasty studies. J Am Co11 Cardiol 1987;9:723. Mullins CE, Nihill MR, Vick III GW, Ludomirsky A, O’Laughlin MP, Bricker JT, Judd VE. Double balloon technique for dilation of valvular or vessel stenosis in congenital and acauired heart disease. J Am Co11 Cardiol 1987:10:107. Grossman W. Profiles in valvular heart disease. In: drossman W, ed. Cardiac catheterization and angiography. Philadelnhia: Lea & Febiaer. Publishers, 1986:359. keager SB. Balloon selection for’double balloon valvotomy. J Am Co11 Cardiol 1987;9:467. Braunwald E. Valvular heart disease. In: Braunwald E, ed. Heart disease. Philadelphia: WB Saunders Company, 1984: 1063. Weyman AE. Mitral stenosis. In: Weyman AE, ed. Crosssectional echocardiography. Philadelphia: Lea & Febiger, Publishers, 1982:150. John S, Bashi VV, Jairaj PS, Muralidharan S, Ravikumar E, Rajarajeswari T, Krishaswami S, Sukumar IP, Sundar Rao PSS. Closed mitral valvotomy: early results and long-term follow-up of 3724 connective patients. Circulation 1983; 68891.
November
CLINICAL
Heart
Journal
in 1925
1988 Volume 116, Number 5, Part 1
INVESTIGATIONS
Percutaneous mitral balloon dilatation sequential single- and doubte-balloon
by a n&w technique
Percutaneous balloon valvotomy by means of a new sequential single- and double-balloon dilatation procedure was performed in 23 patients (aged 13 to 53 years) with severe rheumatic mitral stenosis. The dllatatZon procedure was lnMally performed with a small balloon to primarily dilate the stenotic valve for easier passage of a second balloon catheter and to make the procedure tolerable for severely ill patients; the procedure was then followed by two b&Moons to further increase the mitral valve area (MVA) for effective dilatation of the stenotic mitral orifice. The dllatatlon was successful in all patients; the mitral valve pressure gradient decreased from 19 rt 6 to 5 2 2 mm Hg, the cardiac output increased from 4.0 + 0.5 to 5.2 + 0.6 L/min, and the MVA increased from 0.8 + 0.2 to 1.9 f 0.4 cm2 (p < 0.01 each). The MVA after dilatation was relative to the effective balloon dilation diameter selected (r = 0.57; p < 0.01). A small atrial septal defect was observed In 3 of 23 patients immediately after the dilatation procedure. Mild mitral regurgitation was produced In 3 of 23 patients by the dllatatlon. We conclude that the sequential single- and double-balloon dilatation procedure can effectively increase the MVA and improve hemodynamlcs in severe mitral stenosis and that the larger effective balloon diameter of 24.8 mm or more (12 ? 18 mm of two balloons) is necessary for effective dilatation. (AM HEART J lg88;116:1161.)
Chunguang Chen, MD, Yipo Wang, MD, Duan Qing, MD, Yushan Lin, MD, and Yufu Lan, MD. Fuzhou, The People’s Republic of China
Preliminary experience with percutaneous mitral balloon dilatation (PMBD) is encouraging, and in many instances PMBD has made it possible to avoid thoracotomy, cardiopulmonary bypass, or both.1-g In developing countries without adequate cardiac surgical resources PMBD may provide an attractive alternative to surgical commissurotomy. Recognizing the importance of introducing PMBD to the population with a high prevalence of rheumatic heart disease in The People’s Republic of China, we began to study the technique of PMBD in 1986 after successful PMBD with a single-balloon technique was reported by Inoue et a1.2 in 1984 and Lock et al.’ in 1985. However, technical difficulties were someFrom the Cardiovascular Center and Union Hospital, Fujian Medical College. Supported by grant No. 87 from the Fujian Scientific and Technological Committee. Received for publication Feb. 9, 1988; revision accepted June 24, 1988. Reprint requests: Chunguang Chen, MD, Cardiovascular Center, Fujian Medical College, Jiaotong Road, Fuzhou/Fujian, The People’s Republic Of China.
times encountered in manuvering a large balloon catheter with redundant balloon material over a severely stenotic mitral orifice, the atria1 septum, and even the femoral vessels. Zaibag et al,3 McKay et al.,4 and Mullins et al.9 reported on the usefulness of a double-balloon technique for dilatation of mitral stenosis. These investigators believed that the double-balloon technique had the advantage of easy manipulation of balloon catheters across the stenotic orifice and produced a larger mitral valve area. By means of a new sequential dilatation technique, PMBD was performed in 23 patients with severe mitral stenosis admitted to the cardiovascular center of Fujian Medical College between April and December, 1987. The sequential dilatation technique modifies the original single and doubleballoon techniques by combining both techniques for PMBD in a dilatation procedure. Initially a relatively small balloon catheter is introduced into the mitral valve orifice and the stenosis is partially dilated. A second balloon catheter is then inserted into the mitral valve, and both balloon catheters are 1161
1162
Chen et al.
inflated simultaneously for maximum dilatation. In this study the immediate results of hemodynamic and clinical improvement and the technical characteristics of the sequential single- and double-balloon dilatation technique are described. METHODS Patients. The study population consisted of 23 patients with mitral stenosis with symptoms severe enough to require surgical valvotomy (Table I). There were 14 females and nine males with a mean age of 31 + 12 (range 13 to 53) years (Table II). All patients had exertional dyspnea, and 7 of 23 had a history of acute pulmonary edema. Five of 23 patients were in chronic atria1 fibrillation. Two of 23 patients had a past history of cerebral arterial embolization more than 6 months before PMBD. Two patients had restenosis after previous surgical mitral commissurotomy. Sixteen patients were in New York Heart Association (NYHA) functional class III, four were in NYHA class II, and three were in NYHA class IV. Two-dimensional echocardiography was performed in all patients, 1 day before valvuloplasty; no patients with a severely calcific and stiff mitral valve or left atria1 thrombus were included in the study. Cardiac catheterization. Right- and left-sided heart catheterization was performed by means of a percutaneous technique via the left femoral vessels. After pulmonary pressure, right ventricular pressure, aortic pressure, left ventricular pressure, pulmonary capillary wedge pressure,andcardiacoutputwererecordedbytheFickprinciple, transseptal left-sided heart catheterization was performed with a 8F Mullins transseptal sheath, dilator, and Brockenbrough needle via the right femoral vein. Simultaneous pressure tracings from the left atrium and left ventricle were recorded to document mitral valve stenosis and determine the pressure gradient across the mitral valve. After complete hemodynamic measurements were obtained tine left ventriculography was performed with a retrograde pigtail catheter in the left ventricle for assessment of mitral regurgitation. The severity of mitral regurgitation was graded semiquantitatively from classes I to IV.‘O Percutaneous mitral balloon catheter valvotomy. Immediately after ventriculography the PMBD procedure was begun. Two guide wires (0.035 or 0.038 inch) were inserted through the Mullins transseptal sheath into the left atrium. After withdrawing the sheath and leaving the guide wires in the left atrium, a 7F Critikon large-lumen balloon-tipped pulmonary artery catheter (Critikon, Inc., Tampa, Fla.) (able to accommodate a 0.038 inch guide wire) was introduced over a guide wire into the left atrium and then across the mitral valve in the left ventricle. After the guide wire was positioned near the left ventricular apex and well coiled in the left ventricle, the Swan-Ganz catheter was withdrawn leaving the guide wire coiled in the loft rron+-;n’r ._A._*i. K’itli the same procedure a second guide wire was inserted into the left ventricle. A deflated 10 to 18 mm dilatation balloon catheter (Mansfield Scientific Inc., Mansfield, Mass.) was advanced along one guide wire
American
November 1988 Heart Journal
and positioned across the mitral valve. The balloon was inflated to 4 atmospheres for 6 to 11 seconds with 1:l saline solution and 76% Urografin. The procedure was repeated until the waist of the balloon disappeared and/or the inflation balloon moved with systole and diastole, indicating achievement of an increase mitral orifice with the corresponding balloon catheter. After hemodynamic measurements were obtained by Swan-Ganz catheter in the pulmonary position and pigtail catheter in the left ventricle, a second 10 to 15 mm balloon catheter was introduced along the other guide wire and positioned along side the prepositioned balloon catheter across the mitral valve. The two balloons were inflated simultaneously for 6 to 15 seconds. The inflation was repeated until the dilatation was considered satisfactory according to the following signs: (I) no waist was observed on the inflated balloon; (2) the inflated balloon moved with ventricular systolic and diastolic phases into the left atrium or left ventricle; and (2) a significant decrease in left atria1 pressure was obtained. After PMBD the balloon catheters were removed and the hemodynamic measurements were repeated. Cine left ventriculography was performed in the same projection as before PMBD. Patients were then transferred to an intensive unit and monitored for 24 hours. Echocardiography was performed to exclude pericardial effusion and tamponade. All PMBD procedures were performed without surgical standby. Statistical analysis. All values are expressed as mean -t 1 standard deviation. Hemodynamic parameters before and after PMBD were compared by Student’s t test. The effective balloon dilation diameters were correlated with mitral valve areas after PMBD by linear regression analysis. A p value of 0.05 or less was considered statistically significant. RESULTS Methodologic characteristics. In our first two patients with a mitral valve area of 0.6 and 0.5 cm2, we used a 25 mm balloon catheter to perform the single-balloon method of Lock et al.’ Although the catheter was introduced through the atria1 septum, the balloon catheter failed to cross through the mitral valve, preventing successful inflation and dilatation of the valve. We then used the doubleballoon technique described by McKay et a1.7 The first smaller balloon catheter with an inflation diameter of 15 or 18 mm was successfully maneuvered across the mitral valve and into the left ventricle. The second balloon catheter was introduced along another guide wire; however, it failed to pass across the mitral valve. We decided to dilate with the first balloon placed across the mitral valve, and this procedure was repeated until hemodynamic measurements of successful dilatation of the stenotic valve were observed. The second balloon was then inserted without difficulty.
Volume Number
116 5, Part 1
Percutaneous
mitral
balloon
dilatation
1163
I. Hemodynamics before and after PMBD
Table
Mean pressures (mm Hg) co (Llmin) B
A
B
A
1
3.2
5.9
33
26
90
91
20
11
18
2
5.5 6.0 5.0
48 21 30
35 18 20
85
3 4
4.0 4.5 3.8
84 95
41 17 24
14 10 12
38 13
5 6 7
4.0 4.2 4.1
5.8 5.1 5.9
16 30 15
22 24
10 IO
6 4 4
8 9 10
3.9 4.5 4.2
4.0 4.8 5.1
25 46 26 22
14 18
20 18 16
10 6
11 12 13
4.3 3.4 4.4 4.2
5.9 5.0 5.0
14 15 16
4.3 3.7
17 18 19
4.3 3.5 3.4
20 21 22
3.6 5.2 3.7 5.1
23
Mean SD
4.0 0.5
PA
5.1 5.1 6.3 5.1 3.8 4.6 4.4 6.3 4.8 5.9 5.2 0.6
24 33
15 12 25
22 32 32 54
18 15 18 38
54 36
38 28
60 25 30
53 18 24
55 25 21 65
50 21 12 47 25
34 14
CO = Cardiac output; PA = pulmonary artery pressure: valve area; B = before; A = after PMBD: SD = standard
12 = aortic deviation.
A0
90 93 88 78 80 70 92
A
98 90 76 75 82
__-~ R
LA
MVA
A0 ___-B
Patient NO.
MVG A
80 86 90 79 84
85 75 69
23 17
6 s 8
88 86 99 98
18 22 18 29
10 8 11 14
76 80 90
78 83 82
17 32 17
80 68 90
93 84 92
80 82 83 7
82 84 85 8
26 23 26 17
10 10 13 12 9 14 11
33 23 6
14 10 3
70
pressure:
After these two cases the procedure for dilatation was always the same starting with the first singleballoon dilatation followed by double-balloon dilatation as described previously. With this sequential dilatation procedure passing of the balloon catheter into the left ventricle was uneventful, and the stenotic mitral valve was successfully dilated in all patients. After the first step of the dilatation procedure it was noted that the guide wires placed in the left ventricle produced fewer ventricular premature contractions, the mitral valve pressure gradient decreased, and the mitral valve area increased (Table III). Patients were then able to tolerate the additional dilatation procedure without difficulty. Always a new waist appeared on the balloons during simultaneous inflation of the two side-by-side balloons across the mitral valve at the beginning of the second step of dilatation, and after several dilatations the waist disappeared again, indicating a further increase in the size of the mitral orifice. The total duration of the procedure averaged 2.5 (range 2 to 3.5) hours, which included all of the pre-
LA = left
atria1
pressure:
B
B
A
4
0.6
8 4
0.5 1.3 0.8
2.2 1.7
6 3 2
20 11
5 2
19 19 15
8 4 6 5
0.6 0.8 0.7
3 5 6
0.5 0.6 0.7
8 6 7 4
0.6 0.6 0.8 0.7
9 5
0.9 0.8
2
0.2
17 23 20 18 26 19 6 = trammitral
valve
2.4 1.8 2.6
0.8 0.7 0.9
18 16 11 12
26 16 29 15
MVG
A
(cm’)
1.7 2.5
0.9 1.1
1.8 1.8 2.3
0.8 1.3 0.3
gradient;
2.1 1.6 1.9 1.7 1.4 1.8 1.4 1.3 1.6 1.6 2.1 2.2 1.9 1.9 0.4 MVA
= mitral
and post-PMBD catheterization procedures. All patients tolerated the procedure well. No medica tion was used for prevention of acute heart failure during the procedure, and no dyspnea or acute pulmonary edema occurred during the procedure. General clinical information. No artery embolization after PMBD was observed in the patients studied. At discharge all patients had improved cardiac function. Fourteen of 23 patients (60%) were in NYHA class I and 9 (40%) were in NYHA class 11. All patients except one were ambulatory on the second day after the PMBD procedure. One patient had acute pericardial tamponade documented by two-dimensional echocardiography. Pericardiocentesis was performed in one patient, and 106 ml bloodlike fluid was aspirated. The patient was then stable and mobile on the third day. All patients except one were discharged 2 weeks after the PMBD procedure. One patient had septicemia on the fifth day after the PMBD procedure and was treated with antibiotics for 4 weeks. This patient was discharged by the sixth week.
1164
Chen et al.
Table
II. Factors
Amerlcsn
relative
to effects of PMBD
Age h-1
MVGR (mm &I
Patient No.
MVA (cm’)
BD (mm)
EBD (mm)
B
50 32
14 30
2.2 1.7
18 & 12 15 +- 12
24.8 22.1
AF
3 4 5 6 7 8 9
9 8 14 14 10 8 10 15 9 11 15 9 21 23 24 9 9 17 13
2.4 1.8 2.6 1.7 2.5 1.8 1.8 2.3 2.1 1.6 1.9 1.7 1.4 1.8 1.4 1.3 1.6 1.6 2.1
15 15 18 18 15 15 15 18 15 12 18 15 15 15 12 10 12 15 18
12 18 12 12 18 18 12 12 18 12 12 18 12 18 12 10 12 12 15
22.1 27.1 24.8 19.7 27.1 27.1 22.1 24.8 27.1 19.7 24.8 27.1 22.1 27.1 19.7 16.3 19.7 22.1 27.1
MI-I MI-I
16 17 18 19 20 21
16 26 26 36 34 19 21 18 32 50 29 42 15 13 38 47 53 37 33
22 23
38 25
14 17
2.2 1.9
18 +- 15 18 f 15
27.1 27.1
10 11 12 13 14
15
MVGR = Transmitral valve gradient reduction by PMBD; MVA = mitral valve EBD = effective balloon dilation diameter: AF = atria1 fibrillation; MI-I = mild mitral septal defect
Hemodynamic changes by PMBD. Data are shown in Table I. All patients had severe mitral stenosis. Before PMBD the mitral valve area calculated by Go&n’s formula was 0.8 k 0.2 cm2. It increased to 1.9 +- 0.4 cm2 after PMBD (p < 0.01). The pressure gradient over the mitral valve decreased from 19 +6 to 5 +- 2 mm Hg by PMBD (p < 0.01). There was a significant increase in the cardiac output and a significant decrease in left atrial and pulmonary pressure after PMBD (Table I). The aortic pressure did not change significantly after PMBD (Table I). Effective balloon tion. The selection
dilation
size and effects
of dilata-
of balloon diameter was not based on the size of the mitral anulus in our study. The randomly selected balloon size in the present study varied from 10 to 18 mm. The effective balloon dilation diameter of the two balloons was calculated according to the equation of Yeager.” Linear regression analysis showed a significant relationship between the effective balloon dilation diameter and the
Associated abnormalities
1 2
* f f k k * + +f * +f -+ + + * f f f
mitral
vralxre ~~00 -c+n_.__- -*“II
P&fBI);
ijie
correiation
coefficient (r) was 0.57 (p < 0.01; (Fig. 1). There was no significant correlation between the effective balloon dilation diameters and reduction in the pres-
November t988 Heart Journal
A MI-I
-
-
MI-I MI-I -
AF
-
AF -
MI-I
-
MI-I -
SMC
PT
-
MI-I, ASD Septicemia AF
-
-
AF
AF SMC, AF
AF
-
MI-I
-
ASD
ASD -
area after PMBD; BD = balloon diameters used for dilatation; regurgitation; SMC = surgical mitral commissurotomy; ASD = atrial
sure gradient (Table II). The magnitude of the pressure gradient reduction was primarily related to the pressure gradient before PMBD, with a correlation coefficient of 0.64 (p < 0.01). Age and mitral valve calcification were not related to the mitral valve area after PMBD. Atrial septaI defects were observed in three patients immediately after PMBD, with pulmonaryto-systemic flow ratios of 1.3: 1, 1.5: 1, and 1.6: 1, respectively. Residual atrial septal defects were not related to the balloon diameter used (Table II). Two patients had mild mitral regurgitation (grade I) before PMBD, and the regurgitation was not changed after PMBD. The new mitral regurgitation with grade I was produced in three patients by PMBD. It occurred in relatively old patients aged 50 years or more (Table II). These three patients all had moderate mitral valve calcification, and one of three patients had previously undergone surgical mitral commissurotomy (Table II). DISCUSSION
The results of the present study show that percutaneous balloon mitral valvotomy is a safe and effective method for increasing stenotic mitral areas
VOlUrn~ 116 Number 6. Part 1
Percutaneous
mitral
balloon
dilatation
1165
.
8’
.
A’
l .
.
. . .
iI:-
.
%4 1 23 !! f .
.
.
.. .. .
.
I+
12
r - 0.51
I
I
I
I
I
I
I
I
14
16
18
20
22
24
26
28
effdve
Fia. 1. Correlation between Y = 5.3 X +33.7 (mm).
. ..
. . .
effective
BBllam
balloon
mlatial
dilation
and relieving symptomatic rheumatic mitral stenosis. The mitral valve area after PMBD was significantly related to the effective balloon dilation diameter. We describe our experience with a new modified technique of sequential dilatation by first using a relatively small balloon for preliminary dilatation and then adding another balloon catheter, which enables both easy manipulation of the balloon catheters across the tight mitral valve and effective increase of the mitral valve area. Rationale of the sequential dilatatlon technique. A balloon catheter with an inflated balloon diameter of 23 to 25 mm needs a venous sheath of 14F (4.6 mm) for introduction into the blood vessel with the balloon completely deflated and balloon material properly wrapped and compressed along the catheter sheath.3x lo It is more difficult to introduce a balloon catheter with redundant balloon material within the cardiac cavity because the balloon material may not be as well wrapped and compressed as it is in the venous sheath after it advances through the sheath.g Usually a dilatation catheter with a round balloon diameter of 8 to 10 mm is necessary to dilate the atrial septum so that a single balloon catheter of 25 mm can be advanced through the septum into the left ventricle during the PMBD procedure.*.4,” Unfortunately the pathologic shape of the rheumat-
DiMmta
diameters
30
(I)
and mitral
valve areas after PMBD.
Table III. Hemodynamics after the first and second of the dilatation procedure MVG (mm Hd
DilQtOtiOt2
First step Second step MVG = Mitral tral valve area.
valve
co (Llmin)
11 -t 5 5*+2 pressure
gradient;
4.6 5.2 CO
-+ -+
0.4 0.6
= cardiac
steps
MVA (cm3 1.3 1.9
* *
output;MVA
_
0.3 0.4 = mi-
ic mitral stenosis resembles a buttonhole at autopsy12 and in the live beating heart the mitral valve orifice demonstrated by two-dimensional echocardiography has an oval shape that is longer in its horizontal than its vertical dimension in most patients with mitral stenosis.‘” Therefore it is not surprising that in severe mitral stenosis with a valve area less than 0.8 cm2 and a diameter less than 10 mm the operator encounters difficulty in maneuvering a large balloon catheter (25 mm) through the mitral orifice into the left ventricle even if it passes through the atria1 septum. With the double-balloon technique each relatively small balloon catheter is more compliant and appears easier to maneuver transseptally and across the mitral valve.7sg The two side-by-side balloon catheters take advantage of the
1166
Chen et al.
oval shape of the stenotic mitral valve. However, in very irregular shaped and very small mitral orifices (<0.6 cm2) difficulty may still be encountered in advancing the second balloon catheter into its proper position across the mitral valve. This has been our experience. The sequential dilatation technique applied in the present study includes two steps to enlarge the stenotic mitral valve orifice. The first step of preliminary dilatation by a dilatation catheter of 15 to 18 mm inflated balloon diameter increases the mitral valve area significantly. This makes the second step easier in that the second balloon catheter can be advanced across the mitral valve without difficulty. The preliminary improvement in hemodynamics (Table III) enables the patients to tolerate better the second step of the dilatation procedure, although the mitral valve area (1.3 + 0.3 cm2) after the first step of the dilatation procedure, which uses a single balloon, was not adequate for satisfactory improvement of cardiac function. The purpose of the second step of the dilatation procedure, which uses the double balloon, is to further increase the mitral valve area for adequate improvement of hemodynamics and cardiac function by PMBD, this is also the purpose of the PMBD used for management of mitral stenosis. In the present study the mitral valve area of 1.9 rt_ 0.4 cm2 after PMBD appears larger than that in the study performed by McKay et aLa In their study PMBD was performed by the single-balloon technique in most patients, and the mitral valve area after PMBD was 1.6 + 0.4 cm*. Although precise comparison of the two studies is difficult, one of the important reasons may be the larger effective balloon dilation diameter by the second step of the double-balloon dilatation in our sequential procedure compared to the single-balloon dilatation technique used by McKay et a1.8 We have demonstrated that the mitral valve area after PMBD was significantly related to the effective balloon dilation diameter and have shown that the selection of two combined balloon catheters of large effective balloon dilation diameter not less than 24.8 mm (12 + 18 mm or 15 +- 15 mm) should be considered for effectively increasing the mitral area (Fig. 1). However, greatly variable results by large effective balloon dilation diameter ~24.8 mm suggest that other factors are also responsible for the efficacy of PMBD, such as the pathologic type of rheumatic mitral stenosis (valvular and/or aubvalvular) and tne size of the mitral anulus.3z 7*l*, l4 The time needed for the sequential dilatation procedure averaged 2.5 hours and was less than the
American
November 1998 Heart Journal
4.0 hours in the study by McKay et al7 with the use of a double-balloon technique. However, the duration of the procedure may be significantly related to the learning curve. According to our experience it takes more time to perform PMBD at the beginning; we now need less than 2 hours to complete a sequential dilatation procedure including pre- and post-PMBD catheterization, which is comparable to the time needed for the single-balloon technique reported by Palacios et a1.s Complications of the sequential procedure. The potential complications of PMBD include mitral regurgitation, thromboembolic episodes, pericardial effusion or tamponade, and atria1 septal defect produced by transseptal left cardiac catheterization as reported by several groups with the use of the single-balloon or the double-balloon technique.1-g A mild increase in mitral regurgitation was produced in 13% of 23 patients with PMBD by means of the present sequential dilatation procedure and appeared in less than 29% of the 78 patients summarized from studies published in 1987.5g7-g The cause of this discrepancy is not clear. Palacios et a1.5 showed that mitral regurgitation was not related to the balloon size selected. Results of the present study suggest that older patients with calcific valves may be more prone to develop mitral regurgitation. It is yet to be determined whether a gradual increase in the size of the mitral valve by the sequential dilatation procedure may contribute to fewer mitral regurgitations. Whether more severe atria1 septal defects will develop with the sequential dilatation procedure by using the same septal puncture for introducing the two balloon catheters is uncertain. Atria1 septal defects were detected in 3 (13 % ) of 23 patients with small left-to-right shunts and were hemodynamically insignificant. This is comparable to the results by others who used either the single-balloon technique or two separate septal punctures with the doubleballoon technique.3* 7*s Indications for sequential balloon dilatation. Immediate results achieved by our sequential balloon dilatation procedure, the single-balloon technique, and the double-balloon technique of others for mitral stenosis are comparable to those of surgical commissurotomy.l-s~ I4 Although the long-term results of PMBD are still unknown, good results may be expected from the long-term results of surgical commissurotomy.14 This is because the mechanism of opening mitral valve stenosis by PMBD is no different from that of closed surgical commissurotomy.6s 12-14Thus PMBD is at least an attractive and alterative method for relief of mitral
Volume Number
116 6, Part 1
Percutaneous
stenosis if not preferable to surgical commissurotomy. Particularly in nonindustrialized countries where the prevalence of rheumatic heart disease is still relatively high12 and cardiac surgical resources are limited, PMBD may provide not only the advantage of a short hospital stay and avoidance of thoracotomy but also a therapeutic chance for patients with severe mitral stenosis who would otherwise have to wait a long time for surgery, as has been the experience at our hospital in The People’s Republic Of China. Until now there has been no comparative study dealing with the question of which balloon dilatation technique should be used. According to results of noncomparative studies with small groups of patients, the double-balloon technique provides a larger effective balloon dilation diameter, produces less arterial pressure reduction during balloon inflation, and makes it technically easier to maneuver the balloon catheters across the valve orifice; thus it may be preferable to the single-balloon technique.3j 5,7,s In severe mitral stenosis, as shown in the present study, the sequential dilatation procedure may overcome the drawbacks of the double-balloon technique with occasional failure to pass a second balloon catheter across a very tight mitral valve stenosis. Also too much time spent introducing the balloon catheters in their proper position may not be tolerated by very sick patients. Therefore the sequential dilatation procedure may be preferable in patients with severe and symptomatic mitral stenosis. However, determination of the method of choice for PMBD requires a larger number of patients for comparative and long-term studies. We thank Dr. C. R. McKay for technical suggestions double-balloon technique and Dr. M. M. Weiss for suggestions and help in preparing the manuscript.
on the critical
mitral
balloon
dilatation
1167
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