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(March 24, 2005). doi:10.1510/mmcts.2004.000588 Copyright © 2005 European Association for Cardio-thoracic Surgery Procedure Ventricular reconstruction or aneurysm repair using a modified linear repair technique with septal patch when indicatedDepartment of Surgery, University of Toronto, Toronto, Ontario, Canada * Corresponding author: * 1221 Gervais Road, RR#1 Waubaushene, Toronto, Ont., L0K 2C0, Canada. Tel. +1-705-534-7382; fax: +1-705-534-1538, E-mail: l.mickleborough{at}on.aibn.com
A presentation of our approach for ventricular reconstruction or aneurysm resection which includes a modified linear closure plus septal patch technique when indicated. Our philosophy regarding reconstruction combined with coronary artery bypass grafting (CABG) versus revascularization alone is reviewed. When reconstruction is indicated, the surgical approach is planned on the basis of information gained from preoperative angiography and study of ventricular anatomy as defined by magnetic resonance imaging (MRI). At operation, the precise limits of resection are determined in the open beating heart by inspection and palpation. Reasons for choosing this approach are given. Techniques for optimizing size and shape of the residual cavity are described. Technique of septal patch exclusion will be outlined. Additional maneuvers for prevention of ventricular arrhythmias will be discussed. Operative mortality and long term results obtained using this approach are reviewed.
Key Words: ventricular reconstruction • aneurysm repair • septoplasty • linear closure
For many years, left ventricular (LV) aneurysm resection has been recommended in patients with coronary disease as treatment for heart failure, angina, thromboembolic complications or to control ventricular arrhythmias. The original procedure as applied to discrete dyskinetic aneurysms included excision of the thin walled sac, leaving behind a rim of scar to facilitate closure, which was accomplished in a linear fashion. Technical modifications have been advocated including the pursestring technique of Jatene [1], the endoaneurysmorrhaphy technique of Cooley [2], the endoventricular circuloplasty of Dor [3] and the modified linear closure and patch septoplasty technique we adopted in 1983 [4]. Recently these techniques have been applied in patients without a discrete aneurysm (ventricular reconstruction, SAVER or RESTORE) as a treatment for congestive heart failure (CHF) due to ischemic cardiomyopathy [5,6]. Controversy still exists over optimal criteria for patient selection, preferred technique for repair and optimal criteria for restoration of cavity size and shape. Since 1983 we have used a uniform approach to left ventricular reconstruction which has been applied in patients with areas of akinesis or dyskinesis. It is our opinion that to be a candidate for ventricular reconstruction, the area of wall motion abnormality should have undergone some degree of thinning, relative to the surrounding walls. We now obtain preoperative assessment of ventricular volumes and details of ventricular wall anatomy (wall thickness) using MRI (Video 1 ).
A Doppler echocardiogram is used to assess associated mitral regurgitation and the need for an additional valve related procedure. Anatomic considerations: in patients with coronary artery disease and a previous infarct, necrotic muscle is replaced by fibrous tissue. When significant scarring occurs, an area of relative thinning often results along the distribution of the infarct vessel (elliptical in shape hence the appropriateness of the modified linear repair). With anterior infarcts (LAD distribution), the infarct often involves the septum and may extend over the apex into the distal portion of the posterior wall. The amount of free wall and septal thinning and the degree of compensatory ventricular dilatation which occurs are highly variable. Papillary muscle dysfunction or displacement due to infarct expansion and remodeling may result in significant mitral regurgitation The repair techniques must be tailored for each individual patient to obtain optimal results. Indications for surgery: we recommend an aggressive approach to revascularization and ventricular reconstruction in patients with coronary artery disease, poor ventricular function and kinetic or dyskinetic area of relative thinning. Surgery is recommended when decompensation first occurs in the following situations:
If repair is delayed, contractile function of the residual viable muscle may deteriorate with further decrease in ejection fraction, increased wall stress and chamber dilatation or adverse remodeling. Surgery should be considered early before operative risk increase or the patient reaches the stage when transplantation is the only reasonable option. Rationale for performing repair on the open beating heart: we recommend performing ventricular reconstruction on the open beating heart for the following reasons:
The procedure is performed through a median sternotomy. Rarely extensive adhesions are encountered. Mobilization of the heart should be kept to a minimum until cannulation of the aorta and the atrium have been accomplished. Single or double venous cannulation may be used (Video 2 ).
The patient is placed on bypass. Temperature is allowed to drift but the patient is not allowed below 35°C because of increased risk of fibrillation at these temperatures. In some cases, with clear cut evidence of transmural scarring and thinning, the extent of the aneurysm is obvious after going on bypass, but such clear cut cases are now rare (Video 3 ).
In most cases, inspection of the anteroapical region reveals an area of patchy epicardial scar mixed with islands of viable muscle. There is no evidence of relative thinning on external examination. A ventricular vent is not inserted at this point as this might cause fragmentation and embolization of intraventricularclot which might be present and which is not always detected by MRI or echo examination pre-op (Video 4 ).
The patient is placed in slight Trendelenburg and the perfusion pressure in the aortic root is maintained at 60 mmHg. Once an incision is made in the ventricle, free decompression into the pericardial cavity prevents opening of the aortic valve, which is kept below the blood level in the operative field by the head down position. A vent in the most superior aspect of the ascending aorta is kept on gravity as a further precaution to avoid air embolism. The area of thinning is identified on the basis of the preoperative MRI. A site for incision is chosen in the thinned wall parallel to but lateral to the LAD. Stay sutures are applied on either side of the proposed incision site. The sutures are elevated and a sponge is held over the site to protect the operating team as the thinned area is opened (Video 5 ).
In patients with intraventricular clot, the incision is extended, the ventriculotomy edges are grasped and retracted with clamps and the clot is mobilized and removed in one piece whenever possible. A teaspoon is often useful to scoop out the friable clot (Video 6 ).
Once all the clot has been removed a ventricular vent is inserted through the right superior pulmonary vein and placed on gentle suction. (Video 7 ).
Any obvious thinned transmural scar is excised (Photo 1 ).
In most cases however, an obvious thin sac of scar is not present. In these cases, the incision is made into an area of relative thinning but not transmural scar, the surrounding walls are palpated between the thumb and fingers. In this way the walls can be assessed for contractility in the completely unloaded state. Areas that do not contract (no wall thickening) are considered for resection. The transition to contracting myocardium limits the extent of resection. Although muscle in these contracting areas may be mixed with visible scar, we suggest that these areas will benefit more from revascularization than resection. Further correlation with viability studies and long-term follow-up will be necessary to confirm that this is so (Video 8 , Photo 2 ).
Before final trimming, the size and shape of the remaining left ventricular cavity is assessed in the beating heart. It is important for this evaluation to rely on knowledge of normal ventricular size and shape, as well as the normal spatial relationships that exist between the papillary muscle insertions and the septum, which must not be distorted in the closure. In patients with marked chamber dilatation, diffuse hypokinesis and distortion of ventricular shape (spherical versus conical) careful consideration must be given to these anatomic landmarks and the limits of resection planned so that the modified linear closure will restore ventricular size and shape towards normal as much as possible (Video 9 ).
When the thinned area extends over the apex, it is a simple matter to extend the incision onto the distal posterior wall, lateral to the posterior interventricular vessels. It is important to preserve these vessels as well as the LAD even if they are occluded proximally. The vessels are potential targets for revascularization and may be important avenues for delivery of cardioplegia during a later phase of the procedure. In these cases the repair will involve the distal posterior wall as well. At the time of closure, a new apex will be created adjacent to the relatively preserved right ventricular apex (Video 10 ).
Modified linear closure Once excision of the thinned nonfunctioning wall has been completed, the incision is closed with mattress sutures of 2-0 prolene, buttressed by felt strips. Unlike the classic description of aneurysm repair, in most cases, there is no rim of fibrous tissue left after the resection to sew to. To close the ventriculotomy, sutures have to be placed in tissue of variable thickness. Bites of the tissue are approximately 1 cm deep. To plicate the length of the incision the sutures are placed further apart on the tissue edge than on the felt strips. As the sutures are tied, the incision is "gathered" which helps restore the shape of the ventricle towards its normal conical shape (Schematic 1 , Video 11 ).
Once all the sutures are in place they are tied starting at the extremes of the ventriculotomy leaving a central area for de-airing. Sutures are tied snugly but not under excessive tension that might result in tearing of the tissue. A column of blood is established in the vent and the vent is clamped. Blood is left behind and ejected from the de-airing site. The lungs are ventilated and the patient rotated from side to side to get rid of air (Video 12 ).
When de-airing is complete the final mattress sutures are tied. Opening the vent to gravity decompresses the heart. The closure is then reinforced with a continuous over and over suture of 2-0 prolene to ensure hemostasis. It is important that these be full thickness bites that are superficial to the original layer of mattress sutures in order to avoid possible intramural hematoma formation (Videos 13 and 14 ).
Following completion of ventricular reconstruction, in patients with suitable coronary anatomy, revascularization is carried out. A graft to the LAD is performed whenever possible. We feel that revascularization of even a small part of the septum may be important in improving the long-term results in these patients. The aorta is cross-clamped and cold blood cardioplegia is given using antegrade delivery via the aortic root or a saphenous vein graft to the right coronary for the RV and retrograde delivery for the LV (Video 15 ).
We have previously described similar reconstruction techniques for use in patients requiring reconstruction of the posterior or inferior wall [7,8]. In patients with significant MR which is not corrected by the ventricular reconstruction, an additional valve related procedure (valvoplasty or valve replacement) is indicated.
Patch septoplasty technique
The size of the septal aneurysm is measured and a similar shaped patch of preserved bovine pericardium is cut and applied to the left ventricular aspect of the septum. The patch is sewn to the surrounding normal septal muscle on three sides with a continuous 4-0 prolene running suture anchored at both ends to maintain adequate tension (Schematic 3 , Videos 16 , 17 , 18 ).
The patch is pulled anteriorly and trimmed to the appropriate size (Video 19 ).
The anterior edge of the septal patch is incorporated into the anterior modified linear closure (Video 20 ).
Prevention of ventricular arrhythmias Rationale: in patients with ischemic cardiomyopathy, ventricular arrhythmias are a major source of morbidity and mortality. The CABG patch trial showed that revascularization alone is of significant benefit inpreventing recurrence of ventricular arrhythmias in patients with poor ventricular function [9]. In the past, in those with sustained ventricular tachycardia, use of an intraventricular mapping balloon demonstrated that intraoperative ease of induction of the arrhythmias was critically related to mechanical loading conditions of the heart [10] (Video 21 ).
Based on these and other observations [11], it is likely that any procedure that restores ventricular volume and shape towards normal (such as ventricular reconstruction) will reduce the occurrence of ventricular arrhythmias. Mapping studies in patients with antero-apical scarring, showed that the anatomic substrate for the arrhythmias was almost always located in the border zone between scarred and surrounding normal endocardium on the ventricular septum [12]. Ablation procedures such as endocardial scar excision often combined with cryoablation, or creation of peripheral scar after attachment of a septal patch, controlled the arrhythmia. In patients with ischemic cardiomyopathy undergoing ventricular reconstruction, because arrhythmias have an important effect on prognosis, if significant septal endocardial scarring exists, we have included in the surgical approach a visually directed endocardial excision of the scar (Video 22 ).
To address possible deep septal foci, we apply overlapping cryolesions at the periphery of the excision (minus 60°C for 2 min each). This is followed by patch septoplasty if indicated as already described (Video 23 ).
We recently reported [6] the results we have achieved with ventricular reconstruction in 285 patients. The repair was anteroapical in 253. Major indications for surgery included class III or IV congestive heart failure in 61%, angina in 55%, and ventricular tachycardia in 35%. The distribution of preoperative EF is shown in (Graph 1 ).
The area of wall motion abnormality was dyskineticin 40% and akinetic in 60%. The operative procedure included patch septoplasty in 22%, ventricular tachycardia ablation in 41%, mitral valve procedure in 2% and CABG in 93%. The average cross clamp time was 63±25 min and the average pump time was 171±52 min. All patients were successfully weaned from bypass but 50% required inotropic support and 17% required an IABP (intra-aortic balloon pump) Hospital mortality was only 2.8%. During follow-up, which extends to 19 years and averaged 63±48 months, there were 69 deaths. Actuarial survival was 92% at 1 year, 82% at 5 years and 62% at 10 years (Graph 2) .
During follow-up, 9 patients received an AICD. Excluding these patients, freedom from sudden death or recurrent ventricular tachycardia was 99% at 1 year, 97% at 5 years and 94% at 10 years. Among survivors, 67% were symptomatically improved. Pre and post operative MUGA or MRI documented a highly significant increase in EF and decrease in EDVI and ESVI post op. Pre and postop MRI studies show restoration of LV size and shape towards normal (Videos 24 and 25 and Photos 3 and 4 )
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