M operations, with closed mitral valvotomy first reported

Transcription

1 Comparison of Balloon Valvuloplasty With Operative Treatment for Mitral Stenosis Jeffrey M. Cohen, MHS, Donald D. Glower, MD, J. Kevin Harrison, MD, Thomas M. Bashore, MD, William D. White, MPH, L. Richard Smith, PhD, J. Scott Rankin, MD, and David C. Sabiston, Jr, MD Departments of Surgery, Medicine, and Community and Family Medicine, Duke University Medical Center, Durham, North Carolina To determine the optimal role for percutaneous balloon mitral valvuloplasty or open mitral commissurotomy, the outcome of 164 consecutive patients undergoing either percutaneous balloon mitral valvuloplasty, open mitral commissurotomy, or mitral valve replacement for mitral stenosis was reviewed. No preoperative differences existed between percutaneous balloon mitral valvuloplasty and open mitral commissurotomy in age, symptoms, or mitral valve characteristics. Symptoms improved similarly in all groups, and median hospital stays after procedures were 2, 9, and 1 days for percutaneous balloon mitral valvuloplasty, open mitral cjommissurotomy, and mitrai valve replacement (p <.5). Actuarial survivals at 36 months did not differ significantly (83% f 6%, 94% * 4%, and 9%? 4%). Actuarial freedoms from subsequent mitral valve procedures at 36 months were 66% f 7%, 87% * 6%, and 1% f 13% (p <.5), with the linearized rate of subsequent mitral valve procedures being 12% f 3%, 4% f 2%, and 1.2% *.8%/patient-year for percutaneous balloon mitral valvuloplasty, open mitral commissurotomy, and mitral valve replacement (p <.1). Prior mitral commissurotomy increased the likelihood of subsequent mitral procedures after percutaneous balloon mitral valvuloplasty from 1% f 3% to 2% f 7%lpatient-year. (Ann Thorac Surg 1993;56: ) itral commissurotomy is one of the oldest cardiac M operations, with closed mitral valvotomy first reported by Cutler and associates in 1924 [l]. Harken and associates [2] further developed closed commissurotomy in 1948, and Logan and Turner [3] reported the use of a mechanical dilator for the surgical treatment of mitral stenosis in After the introduction of cardiopulmonary bypass, open mitral commissurotomy () under direct vision became feasible, with Kay and colleagues [4] reporting their experience with for mitral stenosis in 196. Today, technical advances have decreased the risk of cardiopulmonary bypass to the point that closed mitral commissurotomy (CMC) is infrequently performed in most major medical centers. Since mitral valve replacement () was first performed by Starr and Edwards [5] in 196, for mitral stenosis has been reserved for those patients with sufficient valvular Calcification or fibrosis to preclude commissurotomy. In 1984, Inoue and associates [6] first described percutaneous balloon mitral valvuloplasty () for symptomatic mitral stenosis. In recent years, use of has expanded with echocardiographic scoring of mitral valve characteristics [7] and with the development of singleballoon [8] and double-balloon techniques [ Because of the hemodynamic benefit that may be obtained from Presented in part at the Poster Session of the Twenty-ninth Annual Meeting of The Society of Thoracic Surgeons, San Antonio, TX, Jan 2527, Address reprint requests to Dr Glower, Department of Surgery, Duke University Medical Center, Box 3851, Durham, NC without an operative procedure, has become the treatment of choice for selected patients with mitral stenosis. Nonetheless, only short-term follow-up data are available for, and few data exist to compare outcome from versus or. Therefore, a retrospective study was performed to examine the hemodynamic benefit, complications, and clinical outcome obtained from,, or in patients with predominant mitral stenosis. Material and Methods Pa tien t Population One hundred sixty-four consecutive patients undergoing,, or for pure or predominant mitral stenosis between 1985 and 199 were examined. Of these 165 patients, 64 were treated with, 4 received, and 6 underwent, with the first being performed in January One patient who underwent followed by and later, 6 who underwent followed by, and 2 who underwent followed by were included in all applicable treatment groups. Selection criteria for or included insignificant mitral regurgitation, minimal mitral valve calcification, and good mitral leaflet mobility by echocardiography. Using the echocardiographic scoring system suggested by Wilkins and co-workers [7], patients undergoing or generally had a score less than 8. Criteria for selecting instead of included physician or patient preference and the presence of left atrial thrombus by echocardiography. Note that, in 1993 by The Society of Thoracic Surgeons /93/$6.

2 Ann Thorac Surg 1993;56: COHEN ET AL 1255 v) c C...- a t;j 2 h c & n 1 5 z. m n I99 Fig 1. Number of patients receiving percutaneous balloon mitral valvuloplasty (), open mitral cornmissurotomy (), or rnitral valve replacement () from 1985 through , 4 patients underwent whereas 28 patients underwent and 1 patients underwent (Fig 1). Excluded from this study were 1 and 66 patients who underwent other cardiac procedures. All patients undergoing a balloon inflation at were included in this study, and 4 patients who had abandoned because of inability to pass the interatrial septum (n = 2) or because of left atrial perforation (n = 2) before balloon inflation were excluded. Follow-up data were complete to 199 in 152 patients (93%), and hospital mortality included death from any cause before discharge or within 3 days of the procedure. Late cardiac events were considered to include all subsequent mitral valve procedures, thromboembolism, anticoagulant-related hemorrhage, sudden death, or death due to cardiac disease. Operative Technique For the and patients, a median sternotomy incision was performed, and the patients were placed on cardiopulmonary bypass with aortic and bicaval cannulation. Myocardial protection consisted of systemic hypothermia to 28"C, topical hypothermia, and cold potassium cardioplegia infused into the aortic root. The left atrium was opened, and left atrial thrombus was removed if present. The mitral valve was then inspected for the following pathologic features: (1) commissural fusion, (2) calcification, (3) subvalvular fibrosis, and (4) length of chordae. Open mitral commissurotomy was performed by opening the fused commissures with sharp and blunt dissection to create a mitral valve orifice diameter of 3.5 to 4. cm'. After cardiopulmonary bypass was discontinued, the repaired mitral valve was inspected for insufficiency by transesophageal echocardiography. Mitral valve replacement was performed with interrupted suture technique using St. Jude (43 patients), Starr-Edwards (9 patients), Carpentier-Edwards (6 patients), or Hancock (2 patients) prostheses. Balloon Valvuloplasty Technique Right- and left-sided heart catheterization was performed via the femoral vessels. Pressure measurements were made with fluid-filled right heart catheters and highfidelity (Millar) left heart catheters. Oxygen consumption was directly measured, and Fick cardiac output was calculated. Mitral valve area was calculated using the Gorlin formula. A catheter with a sheathed needle was introduced via the inferior vena cava into the right atrium, and the needle punctured the interatrial septum so that a catheter could be advanced into the left atrium. Through the transseptal catheter using the double balloon technique, a guidewire was passed transseptally into the left atrium and across the mitral valve, and coiled in the left ventricle. A double-lumen catheter was passed over this guidewire to introduce a second guidewire. Over one wire an 8-mm balloon was positioned midway through the interatrial puncture and inflated to dilate the interatrial opening, and then removed. Two larger balloons (usually 2-mm diameter each) were introduced, one over each guidewire, and once side by side in the mitral valve, they were inflated simultaneously with dilute contrast medium. Postvalvuloplasty data were then obtained after the balloons were removed. Using the single Inoue balloon (Toray, Inc), the left atrium was entered, and a long introducer dilated the interatrial septum. The single balloon was introduced into the left atrium and manipulated with an internal guiding wire into the left ventricle. The distal portion of the balloon was then inflated, and the balloon was withdrawn into the mitral valve where the proximal portion was inflated. Forty-nine patients underwent double-balloon, and 15 patients underwent single Inoue balloon. Data Analysis Calculation of long-term survival and the incidence of subsequent mitral valve procedures was performed using the Kaplan-Meier technique. Risk factors for subsequent mitral valve procedures were determined using the Cox proportional hazards model, and the effects of various risk factors on Kaplan-Meier plots of survival or freedom from subsequent procedures were compared using the Cox-Mantel or the Peto-Wilcoxon tests. Differences between the treatment groups in age, hospital stay, prior procedure, preoperative risk factors, mitral valve gradient, mitral valve area, pulmonary artery systolic pressure, postoperative embolism, and subsequent procedures were tested for statistical significance by Student's t, 2, or Fisher's exact test as appropriate. A p value of.5 or less was considered significant, and all data were expressed as mean 2 standard deviation unless otherwise indicated. Results Clinical Characteristics Before Procedure The pertinent preoperative clinical characteristics before,, or are summarized in Table 1. The three patient groups were similar in age, presence of other comorbid disorders, presence of mitral regurgitation, and baseline New York Heart Association (NYHA) classification of congestive heart failure (Fig 2). The and patients differed only in a higher incidence of male sex and in absence of left atrial thrombus among

3 1256 COHEN ET AL Ann Thorac Surg 1993;56: Table 1. Patient Characteristics Before Procedure Variable No. of patients Total Female.53 (83%) 39 (98%)b* 53 (88%) Male 11 (17%)a 1 (2%)b, 7 (12%) Average age (y) (range) 5? 12 (26-81) 53 f 12 (29-81) 55 f 12 (28-78) Mitral regurgitation (3%) 1 (25%) 19 (32%) 2+ 1 (16%) 4 (1%) 9 (15%) Mitral calcification 12 (19%b)c 1 (25%b)c 31 (52%Pb Other valve disease (2+) 15 (23%) 4 (1%) 9 (15%) Previous MC 12 (19%) 11 (28%) 21 (35%) Previous (%) 2 (5%) 6 Atrial fibrillation 37 (58%) 24 (6%) 44 (73%) Left atrial thrombus (%)- 4 (1%)b 6 Other comorbid disorders 39 (61%) 2 (5%) 35 (58%) a p <.5 versus. MC = mitral commissurotomy; valvuloplasty. p <.5 versus. p <.5 versus. = mitral valve replacement; = open mitral commissurotomy; = percutaneous balloon mitral patients. The patients were more likely to have mitral valve calcification on fluoroscopy than or patients, and patients were more likely than patients to have had a previous. Hemody nam ic Res u 1 ts All 64 patients underwent cardiac catheterization before and after, and 6 had an echocardiogram before. There were 38 cardiac catheterizations and 33 echocardiograms performed before in the 4 patients. Of the 6 patients, 53 underwent preoperative cardiac catheterization, whereas the remaining 7 patients had preoperative echocardiographic 1 L I 5 8 t 4-- m $ 2 - a - (Llminlrn2) studies. Hemodynamic data in the three treatment groups are presented in Figure 3. Before procedures, all groups were similar in mean mitral valvular gradient, mitral valve area, pulmonary artery systolic pressure, left ventricular diastolic pressure, and cardiac index except that and patients had slightly higher mitral valve gradients than patients, and patients had a lower cardiac index and higher pulmonary artery pressure than patients. Ejection fraction did not differ before the Mean Mitral 2o 15 Gradient (mmhg) 5 - Mitral Valve 2. 6 Area (cm2) g 2 a n I I1 111 IV I II 111 IV I II 111 IV Functional Class Before Procedure 1 I I I II 111 IV I I1 111 IV I II 111 IV Functional Class at Followup Fig 2. New York Heart Association functional classification for congestive heart failure before procedure or at last follow-up after percutaneous balloon mitral valvuloplasty (), open rnitral commissurotomy (OMO, or mitral valve replacement (). 25 I I Systolic 6 PA Pressure 4 (mmhg) 2 3. I T I 4, 1 T l- l- Fig 3. Mitral valve gradient, mitral valve area, systolic pulmonary artery (PA) pressure, and cardiac index before mitral valve replacement (pre), before open mitral commissurotomy (pre), and before and after percutaneous balloon mitral valvuloplasty (pre and post). All values are mean -+ standard deviation. (*p <.5 versus pre.)

4 Ann Thorac Surg 1993; COHEN ET AL 1257 Table 2. In-Hospital Complications Complication No. of patients Hospital death 1(2%) 1(2%) 2(3%) Atrial septa1 shunting 8 (13%) N/A N/A New atrial fibrillation 1 (2%Pb 8 (2%) 7 (12%) Systemic embolus 4(6%) O(O%) 1(2%) New mitral regurgitation (22+) 4 (6%) 1 (2%) N/A Groin hematoma 2 (3%) N/A N/A Cardiac perforation 1(2%) N/A N/A Bleeding requiring operation N/A 1(2%) 3(5%) Wound infection N/A 1(2%) 1(2%) a p <.5 versus.. = mitral valve replacement; open mitral commissurotomy; valvuloplasty. p <.5 versus. p <.5 versus N/A = not applicable; = = percutaneous balloon mitral three procedures, being , , and.54 *.11 in the,, and patients, respectively. Data obtained immediately after demonstrated an increase in mitral valve area, a decrease in mean mitral valve gradient, and a decrease in pulmonary artery systolic pressure (see Fig 3). Optimal results from, defined as mitral valve area of 1.5 cm2 or more and no more than 2+ mitral regurgitation, were obtained in 53 of 64 patients (83%). Four patients (6%) had significant (22+) new mitral regurgitation after, and 3 of the 7 patients with a residual valve area of less than 1.5 cm2 were among the first 5 patients to undergo in Operative Findings In 1 patient and 3 patients, left atrial thrombus that was not detected by echocardiography was discovered and removed. In 4 patients, mitral reconstruction was performed with resection of calcium from both mitral commissures in 1 patient and lengthening of the chordae in 3 other patients. Complications Table 2 compares in-hospital complications for the three procedures. Right heart oximetry after revealed a left-to-right shunt through the atrial septostomy with a pulmonary-to-systemic flow ratio greater than 1.3:l but less than 1.5:l in 8 patients (13%). Two patients were taken to the operating room emergently after elective. One underwent mitral valve replacement because of 4+ mitral regurgitation and was noted intraoperatively to have a tear in the anterior leaflet of the mitral valve. In the other patient, pericardial tamponade developed after successful, and an immediate left anterior thoracotomy was performed with the repair of a pin-sized perforation of the left ventricular apex. No further procedure was performed on the mitral valve. Traumatic pericardial effusion occurred during attempted in 1 patient and was treated by pericardiocentesis. By angiography, the degree of mitral regurgitation did not change in 56 patients (88%) and mitral regurgitation increased one grade in 5 patients (8%). One patient each experienced an increase of more than one grade from to 2+ or from 2+ to 4+, and 1 patient experienced a four-grade increase. By echocardiography, 1 patient had moderate mitral regurgitation after commissurotomy, but mitral valve replacement was not performed because of small left atrial size. Thromboembolic events occurred in 4 patients (6%) of the group and 1 patient (2%) of the group. The risk of thromboembolism after was not clearly related to prior thromboembolism, prior atrial fibrillation, or atrial fibrillation after the procedure. Groin hematoma occurred in 2 patients (3%) of the group, but neither required vascular surgical repair. New onset of atrial fibrillation was significantly less common after than after or (see Table 2). There were no procedural deaths occurring in the group, but there was one hospital death (2%). This patient was a 66-year-old woman with atrial fibrillation and coronary artery disease who had no change in her mitral valve area after. She was referred for and coronary artery bypass grafting 8 days later, but she died postoperatively of rupture of the posterolateral left ventricle. One hospital death (2%) occurred in the group in an 8-year-old woman with atrial fibrillation who died 69 days postoperatively of respiratory failure. Two deaths occurred after, one in a 63-year-old woman who died of ventricular arrhythmias on the first postoperative day, and the other in a 42-year-old man with steroid-dependent lung disease who died of respiratory failure 8 days postoperatively. Median hospital stay after was 2 days (range, 1 to 32 days) compared with 9 days for (range, 6 to 69 days) and 1 days for (range, to 8 days) ( p <.5 versus and ). Follow-up Complete follow-up studies were achieved in 63 patients (98%), 37 patients (92%), and 51 patients (83%). Mean follow-up was months for (range, 1 to 59 months), 45 k 24 months (range, 1 to 84 months) for, and 34 * 26 months (range, 1 to 83 months) for. All but one death, one death, and two deaths were due to cardiac disease (Table 3). There were a total of nine late deaths after. Among the five deaths that resulted from heart failure 4 to 37 months after, two occurred subsequent or, and three were in patients who were poor operative candidates due to advanced age (83 years), disabling stroke, or renal failure. Two patients died of cerebral embolism occurring 13 to 23 months after. One patient died suddenly after 43 months, and 1 patient committed suicide 36 months after (see Table 3). Survival after was 95% * 3% at 12 months and 83% +. 6% at 36 months and did not differ significantly from survival after or (Fig 4). Two deaths occurred after discharge: one due to congestive heart failure following aortic and mitral valve

5 ~ 1258 COHEN ET AL Ann Thorac Surg 1993; Table 3. Early and Late Deaths Time of Death Patient Age Subsequent After Initial No. (y) Procedure Procedure Cause of Death , CABG , AVR, CABG ,AVR days 4 mo 5 mo 13 mo 19 mo 23 mo 22 mo 36 mo 37 mo 43 mo 69 days 26 mo 46 mo days 2 mo 8 days 3 mo 11 mo 13 mo 61 mo I LV rupture after Cerebral embolus Cerebral embolus Suicide Sudden Respiratory failure Cerebral embolus Arrhythmia Respiratory failure Cerebral embolus Pneumonia AVR = aortic valve replacement; CABG = coronary artery bypass grafting; LV = left ventricular; = mitral valve replacement; = open mitral commissurotomy; = percutaneous balloon mitral valvuloplasty. replacements 46 months after, and the other due to a systemic embolus 26 months after. Survival after was 94% * 4% at 12 months and 9% f 6% at 6 months (see Fig 4). Five patients died following discharge after. Three died of congestive heart failure 2, 13, v) 6 4 2o 1 _ a 6 Time (Months) I N at Risk Fig 4. Patient survival * standard error after percutaneous balloon mitral valvuloplusty (), open mitrul commissurotomy (), or mitral valve replacement (). Table 4. Subsequent Mitral Valve Procedures Patient No Age Prior Subsequent (y) Procedure Procedure Reason Time MR... ICABGxl CMC x 2 AVWMVWCABG IAI X l CMC MR IASD MR... /MV repair/ ASD & IMR CMC CMC... IASD CMC CMCx2... CMC MVWAVR... IASD... MVWCABG X 1 /MR MR IMRI A1 MR 1 day 8 days 2 mo 2 mo 3 mo 3 mo 4 mo 4 mo 6 mo 7 mo 8 mo 11 mo 11 mo 14 mo 16 mo 18 mo 24 mo 27 mo 31 mo MR 6 mo IAVR IAS 8mo mo 39 CMC 33 mo 56 CMC /MR 39mo /MR 52mo mo IMR 73mo A1 = aortic insufficiency; AS = aortic stenosis; ASD = atrial septa1 defect closure; AVR = aortic valve replacement; CABG = coronary artery bypass grafting; CMC = closed mitral commissurotomy; MR = mitral regurgitation; = mitral stenosis; MV = mitral valve; = mitral valve replacement; = open mitral commissurotomy; = percutaneous balloon mitral valvuloplasty. and 61 months postoperatively. One patient died of cerebral embolism 3 months postoperatively, and 1 patient died of pneumonia ll months after. Survival after was 92% f 4% at 12 months and 9% -+ 4% at 6 months (p >.2 versus or ). Table 4 compares the late procedures occurring after,, or. Two patients with porcine valves required redo after 71 and 73 months for mitral stenosis or regurgitation. Freedom from subsequent mitral valve procedures was 86% f 13% 72 months after, significantly greater than after or (p <.1) (Fig 5). The linearized rate of subsequent mitral valve procedures after a mean of 36 months of follow-up after was 1.2% f.8%/patient-year. Freedom from all cardiac events 48 months after was

6 Ann Thorac Surg 1993; COHEN ET AL N at Risk Time (Months) Fig 5. Freedom from subsequent mitral valve procedures standard error after percutaneous balloon mitral valvuloplasty (), open mitral commissurotomy (), or mitral valve replacement (). 84% f 6%, which was significantly greater than but not (Fig 6). Six of 4 patients (15%) required late mitral valve procedures, including 5 patients undergoing and 1 undergoing aortic and mitral valve replacements. At the time of operation, 2 patients had predominant mitral stenosis, 3 had mixed mitral stenosis and regurgitation, and 1 patient had mitral regurgitation. The time to subsequent procedure after ranged from 6 to 52 months. Of the 6 patients requiring late procedures, 2 had a previous mitral commissurotomy and 1 patient had a before. The freedom from subsequent mitral valve procedures after was 87%? 6% at 36 months and 78% 5 8% at 6 months (see Fig 5), with the mean linearized rate of subsequent mitral valve procedures being 4% f 2%/patient-year. Freedom from all cardiac events 48 months after was 8%? 7% (see Fig 6). After, 19 patients (3%) required subsequent mitral valve procedures including (l), (2), /closure of atrial septal defect (2), (8), I closure of atrial septal defect (2), MVWaortic valve replacement (l), MVWcoronary bypass (2), and MVlUaortic valve replacement/coronary bypass (1). Eleven patients N at Risk Time (Months) Fig 6. Freedom from all cardiac events * standard error after percutaneous balloon mitral valvuloplasty (), open mitral commissurotomy (), or mitral valve replacement (). Table 5. Predictors of Subsequent Mitral Valve Procedure After Percutaneous Balloon Mitral Valvuloplasty, Open Mitral Commissurotomu, or Mitral Valve Revlacement" Multivariate Univariate P+. standard Factor 2 p 2 p error Initial procedure Coronary artery disease Body surface area Mitral regurgitation Sex Age Prior commissurotomy Mitral valve area Other valve disease Mitral calcification * a Initial procedure = (1) percutaneous balloon mitral valvuloplasty, (2) open mitral commissurotomy, or (3) mitral valve replacement. had predominant mitral stenosis at reoperation, whereas 5 had mitral regurgitation and 3 had combined mitral stenosis and regurgitation. The median time to subsequent procedures was 6.5 months. The freedom from subsequent mitral procedures was 81%? 5% at 12 months and 66% f 7% at 36 months (see Fig 5), significantly less than after or (p <.1). The mean linearized rate of subsequent mitral valve procedures was 12% 2 3% per patient-year after. Freedom from all cardiac events 48 months after was 46%? 12%, which was significantly less than or (see Fig 6). The frequency of cardiac events within 6 months of was 6% (6/1) for the first 1 patients undergoing and was 15% (8/54) for the subsequent 54 patients (p <.1 versus first 1 patients). For all 165 patients with mitral stenosis, multivariate analysis using the Cox proportional hazards model demonstrated the original mitral valve procedure ( versus versus ) to be the only significant predictor of subsequent mitral valve procedures (Table 5). When patients were considered alone, the only independent predictor of subsequent mitral valve procedure was previous commissurotomy (Table 6). Although the patient numbers are small, prior commissurotomy increased the linearized rate of subsequent mitral valve procedure after from 1% * 3%/patient-year to 2% f 7%/patient-year and decreased freedom from subsequent mitral valve procedures (58% * 14% for prior commissurotomy versus 86% 2 5% for no prior commissurotomy at 12 months; p =.1) (Fig 7). Figure 2 compares the NYHA classification for congestive heart failure in patients before,, or with that at last follow-up. Preoperatively, 83% of patients were severely disabled with NYHA class 111 or IV failure. However,,, and significantly improved

7 126 COHEN ET AL Ann Thorac Surg 1993:56:125&62 Table 6. Predictors of Subsequent Mitral Valve Procedure After Percutaneous Balloon Mitral Valvuloplasty Multivariate Univariate P' standard Factor /? p /? p error Prior commissurotomy f.52 Body surface area Coronary artery disease Sex Mitral regurgitation Age Mitral valve area Other valve disease Mitral calcification NYHA functional class, with 82% of patients, 73% of patients, and 86% of patients being in NYHA functional class I or I1 at last follow-up ( p <.1 versus before procedure). The,, and groups did not differ significantly in postoperative or preoperative NYHA functional classification (p >.7). Comment Closed mitral commissurotomy and are wellestablished surgical procedures for pure mitral stenosis with good immediate clinical and hemodynamic results. They also have a low reported operative mortality rate of % to 3% [12-141, as was seen in the present series. Excellent long-term results have been obtained from CMC by selecting patients with mobile mitral valve leaflets, minimal mitral valve calcification, minimal mitral regurgitation, and no left atrial thrombus. Since experience has decreased the morbidity of cardiopulmonary bypass, has largely supplanted CMC because of the ability to inspect and separate fused chordae and papillary muscles, remove calcium from the leaflets, and remove left atrial clot. These specific maneuvers improved longterm results with, and has been reserved for No Prior C ; TN at Risk Prior C No Prior Commissurotomy t 1 c Prior Commissurotomy t f ' Time (Months) Fig 7. Znfluence of prior commissurotomy on freedom from subsequent mitral valve procedure k standard error after perctrtaneous balloon mitral valvuloplasty. patients with extensive calcification or fibrosis of the mitral leaflets or chordae. Results after for mitral stenosis have also been favorable, with a low mortality rate of % to 4% [8, 9, 111, as seen in the present series. Percutaneous balloon mitral valvuloplasty appears to provide hemodynamic benefit similar to CMC, and the initial improvements in mitral valve gradient, mitral valve area, and pulmonary artery pressures after in the present series are similar to those in other studies of [9-11, 151. In a prospective, randomized comparison of and CMC in 4 patients, and CMC did not differ significantly in hemodynamic or symptomatic improvement after 1 week or 8 months of follow-up [9]. Although the immediate success of has been well documented [9, 1, 151, few data exist regarding late results after. Only one study examined factors influencing late valve failure, finding that mitral valve calcification, greater failure symptoms, and unsuccessful impair survival free from valve replacement after [ll]. Indeed, only one institution has provided intermediate-term Kaplan-Meier estimates of freedom from subsequent mitral procedures after, regardless of risk factors [8]. As with, immediate results after are dependent on patient selection. As described by Wilkins and co-workers [7], relative contraindications to include other valvular or coronary disease likely to need operative intervention, left atrial or left ventricular thrombus, a thickened atrial septum (>4 mm), 2+ or more mitral regurgitation, calcification of mitral valve, and a recent thromboembolic event. Using two-dimensional echocardiography to assess morphologic characteristics of the mitral valve apparatus, Wilkins and co-workers [7] showed that the mitral valve can be graded on echocardiographic valve mobility, leaflet thickening and calcification, and subvalvular disease with a total echocardiographic score of greater than 8 producing suboptimal hemodynamic results after. More recently, transesophageal echocardiography has allowed exclusion of patients with left atrial thrombi, which are often missed using transthoracic imaging. Because patients in the current study lacked postoperative hernodynamic data, and were compared using late functional status and the incidence of complications, reoperation, and death. The restenosis rate after has been well documented, with freedom from reoperation varying between 4% and 9% at 1 years [12, 13, 161. In the present series, the linearized rate of subsequent mitral valve procedures was 4%/patient-year, which is in the range of.5% to 4.6%/patient-year reported previously for [12-14, 161. Several reports have failed to show any effect of prior commissurotomy on the likelihood of reoperation after or CMC [14, 171. In contrast to, has a poorly documented rate of restenosis, with only two institutions reporting a 12% to 16% incidence of restenosis or mitral valve replacement at 24 months [8, 1, 11, 181. In the present series, was associated with a significantly higher incidence of subsequent mitral valve procedures than were

8 Ann Thorac Surg 1993;56: COHEN ET AL 1261 and. Several factors could have contributed to the failure rate after. Palacios and colleagues [18] associated preexisting mitral valve disease (echocardiographic scores > 8) and atrial fibrillation with late valve failure after, and both atrial fibrillation and some degree of mitral calcification were common in the present series (see Table 1). Applying these criteria to the present series, 61% of patients and 44% of patients were less than ideal candidates for. Moreover, the current series represents the initial experience with at this institution, and patient selection and procedural technique have improved with time as evidenced by the incidence of early cardiac events after falling from 6% to 15% after the first 1 patients. In addition, was occasionally performed when operative risk was considered to be excessive due to cormorbid illness or poor ventricular function. The low incidence of mitral regurgitation after in this series may reflect appropriate patient selection as mitral regurgitation has been reported predominantly in patients with more rigid valves [W. Most other studies have not noted an effect of prior commissurotomy on the inifiul success of [ll, 15, 191. Block and associates [lo] did, however, find that patients with prior mitral commissurotomy failed to obtain as much improvement in mitral valve area after as did patients without prior commissurotomy. Despite similar hemodynamic results, Davidson and colleagues [ 191 reported less improvement in symptomatic status after in patients with prior commissurotomy. In a series of 3 patients undergoing with a mean follow-up of 21 months, Medina and associates [8] observed that prior commissurotomy significantly increased the likelihood of restenosis from 2% to 21% at 36 months, despite similar symptoms and hemodynamics in both groups before. Thus, although prior commissurotomy may impair early results from to a minor degree, available data do demonstrate an increased likelihood of late restenosis or operation when is performed after prior commissurotomy. The risk of thromboembolism in both the and groups was low at 3%, which compared favorably with other reports of % to 4% [lo, 12, 13, 181. Currently, patients receive warfarin sodium for 4 to 6 weeks before undergoing elective, and this appears to have decreased the incidence of thromboembolism from. No emboli have occurred since 1989, when routine transesophageal echocardiography before was initiated to screen for left atrial thrombus. The 13% incidence of left-to-right shunting through the atrial septum immediately after did not appear to be clinically significant and resembled the 1% to 3% incidence reported in the literature [lo]. By transesophageal echocardiography, almost all patients have a small atrial septal defect immediately after. Although 38% (3 of 8) of patients with a residual atrial septal shunting underwent closure of the atrial septal defect at the time of elective mitral valve replacement, no patient required operation specifically for atrial septal shunting. One previous report revealed a 42% incidence of elective atrial septal defect closure at the time of mitral valve replacement after [181. The present study provides a concurrent and retrospectively controlled comparison of,, and. Although such a retrospective, nonrandomized study has potential for uncontrolled bias, the and patient groups were surprisingly comparable. Despite greater valve calcification and more extensive mitral valve disease, provided intermediate-term results that compared favorably with those of and in terms of survival, freedom from reoperation, and freedom from all cardiac events. The fact that procedures were performed later in this series and operations were performed earlier might be a source of confounding bias, which could be avoided only by a prospective, randomized trial comparing and. The current study also has the weaknesses of relatively small numbers of patients with relatively short follow-up, especially in the group. Yet, despite the small patient numbers, the present study was sufficiently large to demonstrate significant differences in outcome relevant to improving patient selection and thereby improving treatment results after,, or. Because,, and are all palliative in nature, longer follow-up might diminish the differences between treatment groups with a significant portion of each group ultimately requiring valve replacement. The palliative nature of,, and emphasizes the need for close follow-up after the procedure to allow further intervention before complications of recurrent or persistent mitral valve disease ensue. In conclusion,,, and produced similar symptomatic improvement and comparable survival in patients with predominant mitral stenosis. Percutaneous balloon mitral valvuloplasty offers the patient a shorter hospital stay, decreased cost, a short convalescent period, and avoidance of general anesthesia and a surgical incision, all at the price of increased likelihood of further mitral valve procedures or cardiac events. Because of low early morbidity, has become the initial treatment of choice for selected patients with symptomatic mitral valve stenosis at this institution. Those patients with mobile, noncalcified valves lacking severe subvalvular fusion are the most likely to benefit from. Left atrial thrombus, a thickened atrial septum, prior commissurotomy, and other significant and surgically correctable valvular or coronary disease may be relative indications for over. Because the mechanism of is largely limited to splitting of fused commissures, patients with subvalvular chordal fusion or immobile leaflets secondary to heavy fibrosis and calcification may be left with significant residual stenosis despite. Optimal treatment for these patients requires or. Finally, can offer visual assessment of whether to repair or replace the valve, and may minimize risk of embolization by direct visualization of left atrial thrombus. Although appears to provide a longer interval before reoperation, further follow-up studies are needed to assess the long-term efficacy of relative to or, and, at present, and each have a role in the

9 1262 COHEN ET AL Ann Thorac Surg 1993; management of selected patients with pliable and noncalcified mitral valves. References 1. Cutler EC, Levine SA, Beck CS. The surgical treatment of mitral stenosis: experimental and clinical studies. Arch Surg 1924;9: Harken DE, Ellis LB, Ware PF, Norman LR. The surgical treatment of mitral stenosis. N Engl J Med 1948;239: Logan A, Turner R. Surgical treatment of mitral stenosis with particular reference to the transventricular approach with a mechanical dilator. Lancet 1959;2: Kay EB, Nogueira C, Zimmerman HA. Surgical treatment of mitral stenosis by open technique. JAMA 196;173:164&9. 5. Starr A, Edwards ML. Mitral replacement: clinical experience with a ball valve prosthesis. Ann Surg 1961; 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: Wilkins GT, Weyman AE, Abascal VM, Block PC, Palacios IF. Percutaneous mitral valvotomy: an analysis of echocardiographic variables related to outcome and the mechanism of dilation. Br Heart J 1988;6: Medina A, delezo JS, Hernandez E, et al. Mitral restenosis: the Cordoba-Las Palmas experience. In: Cheng TO, ed. Percutaneous balloon valvuloplasty. New York: Igaku-Shoin, Tun ZG, Reyes VP, Raju BS, et al. Percutaneous balloon versus surgical closed commissurotomy for mitral stenosis. A prospective, randomized trial. Circulation 1991;83: Block PC, Tuzcu EM, Palacios IF. Percutaneous mitral balloon valvotomy. Cardiol Clin 1991;9: Tuzcu EM, Block PC, Griffin BP, Newell JB, Palacios IF. Immediate and long-term outcome of percutaneous mitral valvotomy in patients 65 years and older. Circulation 1992; 85:96% Housman LB, Bonchek L, Lambert L, Grunkemeier G, Starr A. Prognosis of patients after open mitral commissurotomy. Actuarial analysis of late results in 1 patients. J Thorac Cardiovasc Surg 1977; Cohn LH, Allred EN, Cohn LA, et al. Long-term results of open mitral valve reconstruction for mitral stenosis. Am J Cardiol 1985;55: Peper WA, Lytle BW, Cosgrove DM, Goormastic M, Loop FD. Repeat mitral commissurotomy: long-term results. Circulation 1987;76(Suppl 3): The National Heart, Lung, and Blood Institute Balloon Valvuloplasty Registry Participants. Multicenter experience with balloon mitral commissurotomy. Circulation 1992;85: Hickey J, Blackstone EH, Kirklin JW, Dean LS. Outcome probabilities and life history after surgical mitral commissurotomy. J Am Coll Cardiol 1991; Fraser K, Sugden BA. Second closed mitral valvotomy for recurrent mitral stenosis. Thorax 1977;32: Palacios IF, Block PC, Wilkins GT, Weyman AE. Follow-up of patients undergoing mitral balloon valvotomy: analysis of factors determining restenosis. Circulation 1989;79: Davidson CJ, Bashore TM, Mickel M, Davis K. Balloon mitral commissurotomy after previous surgical commissurotomy. Circulation 1992;