Nontransplant cardiac surgery for congestive heart. Septal Anterior Ventricular Exclusion Procedure for Idiopathic Dilated Cardiomyopathy

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1 Septal Anterior Ventricular Exclusion Procedure for Idiopathic Dilated Cardiomyopathy Hisayoshi Suma, MD, Tadashi Isomura, MD, Taiko Horii, MD, and Fumikazu Nomura, MD The Cardiovascular Institute, Tokyo, and Hayama Heart Center, Kanagawa, Japan Background. Eight-year experience with the septal anterior ventricular exclusion procedure for congestive heart failure due to idiopathic dilated cardiomyopathy was evaluated. Methods. In 36 patients (27 men and 9 women with a mean age of 60 years) with heart failure; New York Heart Association class III/IV (21/15); and mitral regurgitation 2 or greater, the procedure was indicated when the diastolic dimension was 75 mm or greater, and the septum was akinetic. A long, narrow oval patch was sutured to form a downsized elliptical left ventricle by excluding the septum and anterior wall. Mitral reconstruction was combined for all patients (26 repairs with undersized ring and 10 replacements with bioprosthesis) and tricuspid repair was added for 16 patients (44%). Results. Hospital mortality was 13.8% (5 of 36), with 6.5% (2 of 31) in elective and 60% (3 of 5) in emergency operations. Ejection fraction increased from 20.9% 6.4% to 27.5% 8.8%, left ventricular diastolic dimension decreased from mm to mm, and left ventricular endodiastolic and endosystolic volume indices decreased from ml/m 2 to ml/m 2 and from ml/m 2 to ml/m 2, respectively. Left ventricular endodiastolic pressure decreased from mm Hg to mm Hg. Brain natriuretic peptide decreased from pg/ml to pg/ml at 1 to 6 postoperative months. Eleven late deaths were noted and were due to heart failure (6), sudden death (4) and stroke (1). The mean New York Heart Association class was 1.7 among the survivors. One- and 3-year survival rates were 67.5% and 60.7%, respectively. Conclusions. The septal anterior ventricular exclusion procedure with mitral reconstruction is a useful option for the treatment of advanced idiopathic dilated cardiomyopathy in extremely dilated left ventricle with akinetic septum. (Ann Thorac Surg 2006;82:1344 8) 2006 by The Society of Thoracic Surgeons Accepted for publication April 24, Presented at the Poster Session of the Forty-second Annual Meeting of The Society of Thoracic Surgeons, Chicago, IL, Jan 30 Feb 1, Address correspondence to Dr Suma, The Cardiovascular Institute, Roppongi, Minato-Ku, Tokyo , Japan; suma@cvi.or.jp. Nontransplant cardiac surgery for congestive heart failure has gained enormous attention over the last decade [1]. Endoventricular circular patch plasty has widely been accepted in treating postinfarction ischemic cardiomyopathy [2, 3], whereas partial left ventriculectomy has failed to show optimal results for nonischemic cardiomyopathy [4]. Undersizing mitral annulopasty [5] has been attempted, receiving favorable results because of its low operative risk with symptomatic relief, but its effect on longevity remains controvertial [6]. Left ventricular volume is an important determinant of the surgical outcome in mitral annuloplasty for a dilated left ventricle [7]. In advanced idiopathic dilated cardiomyopathy, the extent of interstitial fibrosis and the decreased myocardial contraction area in the left ventricle are not uniform [8]. Intraoperative echocardiographic tests have defined the weakest area by evaluating how regional left ventricular segments are altered by disease [1]. The consequence was a site-selected treatment to exclude either the lateral wall or the septum [9]. This report shows our 8-year experience with septal anterior ventricular exclusion (SAVE) in combination with mitral reconstruction to treat advanced heart failure due to idiopathic dilated cardiomyopathy with an akinetic septum. Patients and Methods From 1998 to 2005, 36 patients were enrolled as candidates for the procedure at Shonan Kamakura General Hospital and Hayama Heart Center in Japan under the approval of the Institutional Review Board and after having given informed consent. The diagnosis of idiopathic dilated cardiomyopathy was made by the patient s history, echocardiography, cardiac magnetic resonance imaging, and myocardial biopsy by excluding any specific cardiomyopathies and other nonspecific cardiomyopathies. There were 27 men and 9 women with a mean age of 60 years. Preoperative New York Heart Association (NYHA) class III and IV heart failure was noted in 21 patients (58%) and 15 patients (42%), respectively. Nine patients (25%) were inotropic dependent before the operation (Table 1). Preoperative variables are shown in Table 2. All patients had nonstenotic coronary arteries in coronary arteriograms and no episodes of previous myocardial infarction. All patients had been treated with ACE inhibitor, blocker and other medications for heart failure once before the operation, but they had become 2006 by The Society of Thoracic Surgeons /06/$32.00 Published by Elsevier Inc doi: /j.athoracsur

2 Ann Thorac Surg SUMA ET AL 2006;82: SEPTAL ANTERIOR VENTRICULAR EXCLUSION FOR CHF 1345 Table 1. Preoperative Characteristics Number Patients 36 Male/female 27/9 Age (years), range 60 (48 76) NYHA class III 21 (58%) NYHA class IV 15 (42%) Inotropes dependent 9 (25%) NYHA New York Heart Association. Fig 1. Preoperative cardiac magnetic resonance imaging of a patient with idiopathic dilated cardiomyopathy. Note the widely dilated left ventricle with an akinetic thin septum (Œ) in diastolic (left) and systolic (right) phase. The lateral wall shows increased wall thickness at the systolic phase (2). This is a suitable candidate for the septal anterior ventricular exclusion procedure. (ED end diastole; ES end systole.) ineffective. Mitral regurgitation (2 or more) was noted in all patients, and tricuspid regurgitation was noted in 16 patients. Mitral annuloplasty with an undersized ring (generally 26 mm Carpentier-Edwards Physio Annuloplasty Ring) was our primary choice for the mitral procedure, but mitral valve replacement with posterior chodal preservation using bioprothesis was performed in 10 patients when the left ventricular dimension was extremely large and tethering was severe. Indications for the SAVE procedure were (1) refractory heart failure in NYHA class III or IV, (2) a dilated left ventricle with a diastolic dimension larger than 75 mm, and (3) an akinetic septum with a relatively good lateral wall assessed by preoperative echocardiography, cardiac magnetic resonance imaging, and an intraoperative volume reduction test. Regional differences in ventricular wall motion in advanced idiopathic dilated cardiomyopathy are not very clear compared with myocardial infarction. However, they can be predicted by looking at preoperative echocardiograms in the short axis view or cardiac magnetic resonance imaging to find the weakest area and relatively kinetic area if it exists (Fig 1). Dobutamine echocardiography, if available, can give us further information, and the intraoperative volume reduction test is a useful procedure in making a final decision. The basic concept of the volume reduction test [1] is that changes in left ventricular wall motion and thickness can be seen by transesophageal or epicardial echocardiography during the operation when the left ventricle has been decompressed on cardiopulmonary bypass because wall tension decreases. By decompressing the left ventricle, we were able to see that contraction and wall thickness increase if the area is viable. Then, when the septum was akinetic and the lateral wall was viable with the evaluation (Fig 2), the SAVE procedure was indicated. On the contrary, if the posterolateral wall was thin and akinetic and the septum was relatively good, a modified partial left ventriculectomy [10] was chosen for the ventricular reduction. The surgical procedure is shown in Figure 3. A long and narrow endoventricular patch was placed along the septum with interrupted mattress sutures so that the septum and a part of the anterior wall are excluded. Cardioplegic arrest with blood cardioplegia was used for the mitral valve repair. Then, the aortic clamp was removed, and coronary perfusion was restored to allow the heart to begin beating again. The left ventricular incision was made 2 cm to 3 cm lateral to the anterior descending coronary artery, similar to the Dor proce- Table 2. Procedures and Results Number Associated valve procedures Mitral valve 36 (100%) Plasty/replacement 26/10 Tricuspid valve repair 16 (44%) Operative death 5 (13.8%) Elective operation 2/31 (6.5%) Emergency operation 3/5 (60.0%) Late death 11 (30.5%) Heart failure 6 Sudden death 4 Stroke 1 Fig 2. Intraoperative echocardiography-guided volume reduction test. The left ventricle is dilated and poorly kinetic before the cardiopulmonary bypass (CPB [left]). When the cardiopulmonary bypass was instituted and the left ventricle was partially decompressed, the viable area became thick and kinetic (right). This case showed a good lateral wall and poorly kinetic septum (arrows). The septal anterior ventricular exclusion operation was indicated.

3 1346 SUMA ET AL Ann Thorac Surg SEPTAL ANTERIOR VENTRICULAR EXCLUSION FOR CHF 2006;82: Fig 3. Under a normothermic cardiopulmonary bypass and with the heart beating, the left ventricle is opened. (A) An incision is placed from the apex to the distal diagonal coronary artery anteriorly. (B) Endocardial interrupted mattress sutures are placed over a Teflon strip along the posterior septum from the apex to near the aortic valve. This vertical suture line is important in making the ellipsoidshaped ventricle. (C) The anterior free wall is then excluded by placing transmyocardial interrupted mattress sutures with an epicardial Teflon strip. (D) These mattress sutures are secured to a Dacron patch that is a longitudinal oval shape. (E) After all sutures are tied, the excluded ventricular wall is closed to obtain hemostasis. (SAVE septal anterior ventricular exclusion.) dure, and was extended towards the distal portion of the first diagonal artery. By retracting the ventricular incision with 4 to 5 traction sutures, the inside of the left ventricle is clearly visualized. Then endocardial mattress sutures with Teflon felt (1.5 cm 10 cm) were placed along the posterior septum starting from the apex towards the base. Usually, 5 to 6 mattress sutures are necessary. The corner of the ventricular incision proved difficult in making this endocardial sutures; therefore, a mattress suture was placed transmurally from the epicardium to the endocardium at the end of the ventricular incision. These transmural mattress sutures were sequentially made to the anterior wall along a line 2 cm lateral to the incision. Generally, 8 to 9 mattress sutures are necessary. When these myocardial sutures were completed, all stitches were then sutured to a trimmed patch (Hemashield; Boston Scientific Corp, Natick, MA). The patch should have a long and narrow oval shape (2 to 3 cm 6 to 7 cm) that is larger than the actual effective area. The effective area (1 5to 6 cm) can be very narrow along the short axis and the same length as the ventricular incision along the long axis to make the ventricle into an ellipsoid shape. The external suture flange of the patch was used for reinforcement in the next sutures for closure of the left ventricle. Because the myocardium is fragile, ventricular closure should be made in two layers to insure hemostasis. First, 5 to 6 mattress sutures were used by taking the flange of the patch, then over and over running sutures were made. There was no sizable dead space remaining between the patch and closed ventricular wall. Tricuspid annuloplasty with a partial ring was then performed if necessary. After recovery from the surgical operation, all patients were treated medically with anticoagulants and repeated introductions of -blocker and angiotensin-converting enzyme inhibitors. Follow-up was completed in all patients. For statistical analyses, parametric data were analyzed using Student s t tests, and all data were expressed as the mean SD. Results Hospital mortality was 13.8% (5 of 36), with 6.5% (2 of 31) in elective and 60% (3 of 5) in emergency operations. In 31 hospital survivors, the ejection fraction increased from 20.9% 6.4% to 27.5% 8.8%, the left ventricular diastolic dimension decreased from mm to mm, and the left ventricular end-diastolic and end-systolic volume index decreased from ml/m 2 to ml/m 2, and from Table 3. Changes in Left Ventricular and Hemodynamic Variables Before and After the Operation in 31 Hospital Survivors Variables 1 6 Months Preoperative Postoperative p Value Ejection fraction (%) Diastolic dimension (mm) Endodiastolic volume index (ml/n) Endosystolic volume index (ml/n) Endodiastolic pressure (mm Hg) Systolic pulmonary artery pressure (mm Hg) Cardiac index (L/min/m) Brain natriuretic peptide (pg/m)

4 Ann Thorac Surg SUMA ET AL 2006;82: SEPTAL ANTERIOR VENTRICULAR EXCLUSION FOR CHF 1347 Fig 6. Three-year survival rate in patients with the procedure. (Dashed line elective [n 31]; solid line total [n 36].) Fig 4. Ventriculograms (right anterior oblique view) before (left) and after (right) the septal anterior ventricular exclusion operation. Note the left ventricle is downsized with an elliptical shape. (EF ejection fraction; Preop. preoperative; Postop. postoperative.) ml/m 2 to ml/m 2, respectively. Left ventricular end-diastolic pressure and systolic pulmonary artery pressure decreased from mm Hg to mm Hg and from mm Hg to mm Hg, respectively. The cardiac index increased from L/m 2 to L/m 2. Brain natriuretic peptide decreased from pg/ml to pg/ml at 1 to 6 postoperative months (Table 3). Ventriculograms before and after the operation are shown in Figures 4 and 5. Eleven late deaths were noted, and were due to heart failure (6), sudden death (4), and stroke (1) (Table Fig 5. Ventriculograms (left anterior oblique view) before (left) and after (right) the septal anterior ventricular exclusion operation. Note the contraction of the septum (arrows) improved after the operation. (Preop. preoperative; Postop. postoperative.) 2). The mean NYHA class was 1.7 among the survivors, and no significant left ventricular redilatation was noted in echocardiography in patients at 3 postoperative years. One- and 3-year survival rates were 67.5% and 60.7% (Fig 6), respectively, and the longest survivor was six years and eight months after this type of operation. Comment In the surgical approach for congestive heart failure, ischemic cardiomyopathy has been treated with the Dor operation with favorable results [2, 3, 11], and the Surgical Treatment for Ischemic Heart Failure (STICH) trial is ongoing [12]. Nonischemic cardiomyopathy such as idiopathic dilated cardiomyopathy, however, is still unclear in regrard to target for surgical treatment. Bolling and colleagues [5] have introduced undersizing mitral annuloplasty with a low operative mortality, but its beneficial effect on late survival is as yet undetermined [6]. Our group recently found that the left ventricular volume is a strong determinant for survival with mitral reconstruction for idiopathic dilated cardiomyopathy. Three-year survival rate in patients whose left ventricular endosystolic volume index was either larger than or smaller than 150 ml/m 2 were 42% and 67% (p 0.03), respectively. Based on those results, we felt that ventricular reduction might be effective in addition to the mitral procedure for patients with an extremely dilated left ventricle. Partial left ventriculectomy, however, has failed to show satisfiable results over the last decade [4, 13]. One of the reasons for its unstable results is, we believe, no site selection for ventricular excision [14]. In the beginning, we thought that the extent of myocardial damage was homogeneous in idiopathic cardiomyopathy. After our initial experiences with partial left ventriculectomy, we found a higher incidence of interstitial fibrosis in the septum than in the lateral wall in our surgical specimens for idiopathic dilated cardiomyopathy [8]. Yanagida and coworkers [15] have shown a heterogeneity of wall motion abnormality in idiopathic cardiomyopathy, and

5 1348 SUMA ET AL Ann Thorac Surg SEPTAL ANTERIOR VENTRICULAR EXCLUSION FOR CHF 2006;82: found that the septum was more akinetic than the posteroinferior wall in 8 out of 10 patients. In our experience, nearly half of the patients with advanced idiopathic dilated cardiomyopathy admitted to our hospital have shown an akinetic septum with a relatively kinetic posterolateral wall. Those patients must be unsuitable candidates for partial left ventriculectomy. Therefore, a proper site selection for ventricular reduction is important and an intraoperative echographic evaluation is helpful for this purpose [1, 9]. To exclude the septum, we initially thought that the Dor procedure could be applicable for this purpose, but the fragile myocardium of idiopathic dilated cardiomyopathy made endocardial pursestring suturing difficult. Therefore, we have introduced the use of multiple mattress sutures for patch attachment. By using a long and narrow patch, the postoperative left ventricle forms an ellipsoid shape. The change in ventricular volume is not so striking after the SAVE procedure compared with the partial left ventriculectomy because the latter procedure can excise a large amount of the ventricular free wall. As a consequence, diastolic dysfunction is a major concern in partial left ventriculectomy. We feel that a little larger is less harmful than too small, but further investigations are necessary. Knowing the isolated effects of septal exclusion is desirable, but we have no experience with the SAVE procedure without the mitral procedure, because all the patients had mitral regurgitation 2 or greater. Recent advances in the medical treatment of heart failure are obvious [16]. The 3-year survival rate of 67.9% in our series in elective surgery was similar to that of cardiac resynchronization therapy and better than medical therapy alone, as reported in the Cardiac Resynchronization-Heart Failure (CARE-HF) trial [17]. However, a higher incidence of NYHA class IV (42% versus 6%) and a larger left ventricular end-systolic volume index (181 ml/m 2 versus 121 ml/m 2 ) in our patients compared with the cardiac resynchronization group in the CARE-HF study should be taken into consideration. Moreover, all surgical candidates were those who were admitted with heart failure after having received maximum medical therapy. Currently, an integrated medical and surgical approach for congestive heart failure is becoming increasingly important with refined techniques and new devices. The Acorn cardiac restraint device (CorCap) [18,19] has shown a favorable clinical outcome for dilated cardiomyopathy, and its effectiveness in relation to ventricular volume or dimension is interesting to know. If an extremely dilated left ventricle at a certain degree is found to be an unsuitable candidate for the device, surgical ventricular reduction might become necessary. The limitations of this study include no control group, a small number of patients, a relatively short-term follow-up, and a mixture of procedures in addition to the SAVE procedure. In conclusion, the SAVE procedure in combination with mitral annuloplasty is a useful option for patients with an extremely dilated left ventricle in idiopathic dilated cardiomyopathy. References 1. Suma H, Isomura T, Horii T, et al. Nontransplant cardiac surgery for end-stage cardiomyopathy. J Thorac Cardiovasc Surg 2000;119: Dor V. Left ventricular reconstruction: the aim and the reality after twenty years. 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