Surgical Treatment of Ischemic Heart Failure

Transcription

1 REVIEW Cardiovascular Surgery Circ J 2009; Suppl A: A-1 A-5 Surgical Treatment of Ischemic Heart Failure The Dor Procedure Marisa Di Donato, MD*, **; Serenella Castelvecchio, MD*; Lorenzo Menicanti, MD* Despite the improvements in the treatment of myocardial infarction that have translated into a decline in mortality rates, the incidence of heart failure has increased and, because of the limited number of cardiac donors, nontransplant heart surgery has developed in the past 10 years. Surgical ventricular reconstruction was launched by Dor and defined as endoventricular circular patch plasty repair. It represents a relatively novel surgical approach aiming to restore (bring back to normal) the dilated, distorted left ventricular (LV) cavity in order to improve function. The term surgical ventricular reconstruction/restoration includes operative methods that reduce LV volume and restore its shape. The concept of reducing wall stress through surgical restoration of chamber size and geometry remains the guiding principle behind this innovative technique. Results from different Institutions are uniform and show an improvement in cardiac and clinical status and in survival. The present review will approach the rationale to re-shape the heart on the basis of pathophysiology and cardiac architecture, and will describe the efficacy of the Dor procedure in ischemic dilated cardiomyopathy, as well as some technical aspects and patient selection pathway. (Circ J 2009; Suppl A: A-1 A-5) Key Words: Ischemic heart failure; Patient selection; Surgical ventricular restoration Coronary artery disease in Western countries is responsible for more than 75% of heart failure (HF) cases. 1,2 Despite the improvement in the treatment of myocardial infarction (MI) over the past 4 decades, which has translated into a decline in mortality rates after MI, the incidence of HF in recent decades has increased and greater salvage of high-risk MI patients in recent times may have contributed to this trend. 3 The clinical syndrome of congestive HF (CHF) progresses from no or scarce symptoms (compensated) to moderate or severe symptoms (decompensated). Decompensated HF has advanced structural cardiac disease with symptoms at rest (New York Heart Association (NYHA) class IV or stage D HF) despite optimal medical therapy, and carries an extremely poor prognosis. In the Rematch study, only 8% of patients in the medically treated group were alive at 2 years, with significant costs and resource consumption. 4 Increased chamber sphericity and the presence of mitral regurgitation are markers of poor prognosis and are determined by severe abnormalities in chamber geometry that subtend the progression of the disease, according to the biomechanical model of HF. 5 Advanced, stage D HF affects between 300,00 and 800,000 patients in the United States, which generates an enormous economic burden without obtaining substantial symptomatic benefit or improvement in prognosis. For endstage HF patients, cardiac transplantation is the treatment of choice, but most patients are over 65 years of age (Received November 20, 2008; revised manuscript received February 19, 2009; accepted March 11, 2009; released online May 27, 2009) *Department of Cardiac Surgery, IRCCS San Donato Hospital, Milan, **Department of Critical Care Medicine, University of Florence, Florence, Italy Mailing address: Marisa Di Donato, MD, Department of Cardiac Surgery, IRCCS, San Donato Hospital, Via Morandi 30, San Donato, Milanese (Milan), Italy. marad@tin.it All rights are reserved to the Japanese Circulation Society. For permissions, please cj@j-circ.or.jp or have comorbidities that preclude transplantation; moreover, the scarce number of donors makes the treatment unavailable for most patients on a waiting list. Given these limitations, non-transplant heart surgery has developed in the past 10 years and the role of cardiac surgeons in treating HF patients has changed, although cardiologists are still reluctant to send patients for non-transplant surgical alternatives and guidelines for CHF do not even mention some strategies, such as the Dor procedure. The Dor Procedure In 1985 Jatene described a new technique of performing a circular endoventricular suture (Fontan stitch) to exclude the dyskinetic scar of an aneurysm, 6 and in the same year Dor et al described the use of the endoventricular Fontan suture to rebuild a failing ventricle with an endoventricular patch after extended endocardectomy for ventricular tachycardia. 7 Dor was the first surgeon to demonstrate that the endoventricular patch plasty repair could be applied not only to left ventricular (LV) aneurysm but also to a dilated akinetic ischemic LV. He emphasized the concept of reducing the LV size and reconstructing a more elliptical cavity, treating the dilatation in all its components (anterior, apical and septal), as opposed to linear resection of the aneurysm that left an untouched septal dilatation, creating a distortion of the residual chamber. The concept of excluding all the diseased tissue from the cavity, especially the septum, is the basis of the good results. 7 The Dor technique is a relatively novel surgical approach to restoring (bringing back to normal) the dilated, distorted LV cavity in order to improve function. It implies knowledge and understanding of the remodeling infrastructure, the structural changes leading to geometry abnormalities, the role of compensatory, remote muscle and of stretching mechanisms that lead to electrical disadvantage. 8 The procedure includes coronary grafting and mitral

2 A-2 DONATO MD et al. Figure 1. (Left) Use of internal sizing and shaping device and the position of the patch are shown. Notice that the patch is obliquely oriented towards the aortic tract, parallel to the septum. (Right) Mammary artery graft is in place and the venous sequential distal anastomosis already performed. The opening of the ventricle is shown at the end of the procedure. Notice the everting suture to close the opening with the patch that is tailored during the closure. repair when needed, so it has the potential to treat the 3 components of HF: the ventricle, the vessels and the valve ( triple V as defined by Buckberg). 9 The term surgical ventricular reconstruction/restoration (SVR) includes operative methods to reduce LV volume and restore the ventricular elliptical shape. The concept of reducing wall stress through surgical restoration of the LV chamber size and geometry remains the guiding principle behind this innovative technique. Since the first description by Dor, the procedure has been adopted by many surgeons, but its use is it is not widespread because surgeons have been unwilling to incise and exclude the akinetic segments that may appear normal on the surface; this finding is often encountered after successful early reperfusion that savages the epicardial and myocardial layers but the scar remains in the subendocardial layer and is visible only if the ventricle is opened. The technique has not been standardized yet, and surgeons use essentially 4 variations of LV reconstruction: linear closure by Jatene; 10 modified linear closure by Mickleborough et al; 11 circular closure with a patch by Menicanti and Dor; 12 and double circling closure without a patch by O Neill et al. 13 These different techniques may all be successfully performed when the disease involves mainly the antero-apical wall, but when the septum is deeply involved or the dilatation is only at the septal level, the original Dor technique is the only one that ensures complete treatment of the underlying disease. To date, the technique described by Dor has been applied to all kinds of dilatation involving all segments (anterior, apical and septal). More recently, Menicanti et al 14 introduced the use of a sizer/shaper intraventricular device as a refinement of the Dor technique, emphasizing the importance of re-shaping the LV cavity through patch positioning, which should be inserted deep in the septum and obliquely towards the aortic flow tract in order to obtain an elliptical new cavity. The positioning of the patch follows the Fontan suture that is performed in an oblique plane parallel to the septum, at the level of the transitional zone. In this way, the risk of making the new cavity too spherical, as can happen with the standard Dor technique, was potentially overcome. Moreover, LV surgical reconstruction can be also used for posterolateral dilatation caused by inferior/lateral MI with the occlusion of the circumflex or right coronary artery. In our experience, nearly 98% of patients need concomitant coronary artery bypass grafting (CABG), and many also undergo mitral valve repair (20 25% of cases). Surgical Details of Anterior SVR The SVR operation, as performed in our institution, is conducted on the heart arrested with antegrade crystalloid, or cold blood cardioplegia introduced in CABG is performed first, as completely as possible, almost always on the left anterior descending coronary artery to preserve the upper part of the septum and to guarantee complete revascularization. The LV is opened in the middle of the scar on the anterior wall, with an incision parallel to the left anterior descending artery, starting from the mid portion towards the apex. The LV cavity is accurately checked and thrombi are removed if present; the mitral valve is repaired, when necessary, through the ventricular opening. 14,15 Since 2001 we have been using a sizer/shaper device (Chase Medical, Richardson, TX, USA) filled to ml/m 2 to optimize the size and shape of the new ventricle (Figure 1). The choice of 50 ml is made if the transverse diameter (as taken below the mitral valve) is not very enlarged (<65 mm) and 60 ml is chosen if it is >65 mm. This choice is somewhat empirical, but we think that it is advisable to leave a residual chamber with a normal volume (52±13 ml/m 2 in a series of 52 normal subjects from our echocardiography lab). 16 The Fontan suture is performed with the sizer inside the ventricle, following the conical curvature of the dummy, starting at the level of the new apex, going deep into the septum towards the aortic valve, in an oblique plane, running towards the lateral wall and reaching again at the new apex. The suture is tied onto the dummy in order to reduce the cavity; the dummy is removed and the patch is sutured along the Fontan suture if the opening of the ventricle is 3 cm or greater; if the opening is less than 3 cm the closure is direct, without the patch. The excluded tissue is folded to reinforce the suture.

3 HF and Surgical Ventricular Restoration A-3 Figure 2. Mitral procedure. Views from inside the ventricle. The cavity is carefully explored and thrombi are removed if present (1,2). The papillary muscles are checked (3) and the pledgets at the 2 trigones are shown (4). The sizing device is in place (5) and the patch is sutured (6). Figure 3. Posterior lesions are shown. (Left) Dilatation is mainly between the papillary muscles. (Right) Dilatation is between the posteromedial papillary muscle and the septum. The schema shows 2/0 prolene suture being initiated at the level of the beginning of the dilatation and continuing towards the apex, excluding all the damaged tissue from the cavity (Left). After the opening of the wall, continuous suturing is performed between the posteromedial papillary muscle, bringing the posterior wall against the septum (Right). Mitral Repair We repair the valve if mitral insufficiency is moderate/ severe or if it is mild but accompanied by mitral annulus dilatation (>38/40 mm). An atrial approach is avoided because our technique reduces the mitral annulus by accessing it through the same ventricular incision that is used to perform SVR. After opening the LV cavity, each papillary muscle head is identified and the mitral valve leaflets and chords are inspected. The posteromedial fibrous trigone is visualized, and a pledgetted 2/0 polyester suture is placed from the ventricle side to the atrial side. Progression of the 2 arms of this stitch is made with a running suture and the course direction extends towards the anteromedial trigone. The 2 arms of the suture are placed through the anterolateral trigone and a second pledget is inserted; the entire posterior annulus becomes completely bounded by the suture (Figure 2). In order to undersize the mitral annulus, avoiding valve constriction, a sizer (26 mm) is introduced within the mitral orifice and the suture is tied against the second pledget. Posterior SVR Limited data are available on surgical repair of LV dilatation caused by inferior/lateral MI. Two types of posterior lesion may occur after inferior MI: (1) dilatation is mainly between the 2 papillary muscles or (2) dilatation between the posteromedial papillary muscle and the septum. Figure 3 shows the 2 different techniques of linear suture that are used in our hospital for LV dilatation after inferior MI. Patient Selection Decision-Making Patients with symptoms of HF should be referred to a

4 A-4 DONATO MD et al Survival in NYHA class 4 following SVR % n=308 51% months Figure 4. Kaplan-Meier survival curve in patients with preoperative advanced functional class. Notice that the 5-year survival rate is 51%; the expected survival rate in this population is 25% at 3 years. NYHA, New York Heart Association; SVR, surgical ventricular reconstruction. cardiologist for assessment of the aetiology and severity of LV dysfunction. Coronary angiography and echocardiography should be performed at this stage to differentiate between ischemic or non-ischemic disease; young and very symptomatic patients are referred to a transplant center or to an invasive cardiologist to undergo percutaneous coronary angioplasty, internal cardioverter defibrillator (ICD) implantation or resynchronization therapy or CABG, mitral repair or ventricular reconstruction or mechanical support. 17 Patients should be carefully evaluated by a multidisciplinary team in order to decide the best therapeutic strategy and detailed information should be obtained on (1) coronary vessels, (2) myocardial structure, (3) cardiac function, size and geometry, (4) viability, (5) oxygen consumption, (6) comorbidities such as respiratory, renal or liver insufficiency. The appropriate candidates for LV reconstruction are patients who suffered a MI, have a dilatation of the LV and an area of asynergy (either dyskinetic or akinetic) of 35% or more of the ventricular perimeter. Patients should have symptoms of HF and/or angina or intractable ventricular arrhythmias. The LV should be carefully evaluated during coronary angiography (ventricular angiography in right and left anterior oblique projections) or during a complete echocardiographic study in 4CH, 2CH, parasternal long- and short-axis views, with nuclear or magnetic resonance study. The objective with any imaging technique being used for patient selection, treatment planning and follow-up is to assess the status of the infarcted and remote regions, their viability, the extent of geometric abnormalities, the extent and severity of regional wall motion abnormalities, and valvular competence (especially the mitral valve). Outcome Results from LV reconstruction have been favorable and consistent between different groups SVR improves symptoms and long-term survival for patients with ischemic cardiomyopathy and severe HF. Its beneficial effect in reducing LV volume, improving cardiac function, reducing ventricular arrhythmias and reducing mitral regurgitation has been largely accepted. A reduction in mechanical intraventricular dyssynchrony has also been demonstrated. 28,29 The acute beneficial effects on systolic function are largely maintained chronically, so SVR induces a significant reverse remodeling associated with clinical improvement and improved survival. Interestingly, the entity of both ejection fraction (EF) improvement and LV volume reduction is Rate and causes of hospitalization (FUP 2-89 m) Stroke MI Angina A HF EF</=30% EF>30% Hospit/yr Hospitalization % Rate and type of cardiac procedures during FUP (2-89 m) Total Re-do (Mitral) ICD EF</=30% CRT+ICD EF>30% CRT PTCA % San Donato Hospital, Milan Figure 5. Rate of cardiac events at FUP in patients undergoing surgical ventricular reconstruction. (Top) Rate and causes of hospitalization. (Bottom) Rate and type of cardiac procedure in patients with preoperative EF 30%. Notice the low rate of ICD implantation in MADIT II matching patients (EF 30%). EF, ejection fraction; Hosp/yr, rate of hospitalization per year; HF, heart failure; A, arrhythmias; MI, myocardial infarction; FUP, follow-up; PTCA, percutaneous coronary angioplasty; CRT, cardiac resynchronization therapy; ICD, internal cardioverter defibrillator.

5 HF and Surgical Ventricular Restoration uniform in all the reported series, varying from +6 to +15 absolute points for EF, and from 30% to 45% reduction for LV end-systolic volume. Also, survival rates appear uniform among different studies, being near 80% at 5 years and 60% at 10 years, on average. 30 Moreover, the rate of re-hospitalization for HF is reported to be low. 31,32 These results are similar to those reported at 6 months after heart transplantation, and a study from Cotrufo et al showed no differences in mortality, clinical improvement or survival rate between a comparable group of patients with dilated ischemic cardiomyopathy who underwent either SVR or heart transplantation. 32 The 5-year survival rate in patients with preoperative advanced HF (NYHA class IV) operated in our hospital is shown in Figure 4. Follow-up in a series of our patients operated on between 2001 and 2008 demonstrated a low rate of hospitalization for cardiac causes and a low rate of cardiac procedures following SVR; in particular, the rate of ICD implantation in a series of 116 patients with a preoperative EF 30% (Madit II matching) was extremely low (6.8%) (Figure 5). In conclusion, SVR for post-mi dilated cardiomyopathy is an effective option treatment, applicable not only for dyskinetic aneurysm but also for diffusely dilated cardiomyopathy. Although randomized data are not available yet, observational results are all in full agreement and they only need to be confirmed by the ongoing STICH trial (Surgical Treatment of Ischemic heart disease) that will definitely demonstrate whether SVR added to CABG improves 3-year survival free of hospitalization when compared with CABG alone. 33 References 1. Mc Murray JJ, Stewart S. Epidemiology, aetiology and prognosis of heart failure. 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