Asian Cardiovasc Thorac Ann 2006;14:231-234
© 2006 Asia Publishing EXchange Ltd
Left Ventricular Aneurysmectomy: Tailored Scar Excision and Linear Closure
Maninder S Kalkat, FRCS,
Uday Dandekar, FRCS,
Chris Smallpeice, FRCS,
Jitender Parmar, FRCS,
Chris Satur, FRCS,
Adrian Levine, FRCS
University Hospital of North Staffordshire, Stoke-on-Trent, United Kingdom
For reprint information contact: Maninder S Kalkat, FRCS Tel: 44 192 262 4653 Fax: 44 121 627 5736 Email: mankalkat{at}hotmail.com, Department of Cardiothoracic Surgery, University Hospital of North Staffordshire, Stoke-on-Trent, ST4 7LN, United Kingdom.
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ABSTRACT
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Coronary artery bypass surgery with or without aneurysmectomy is used to treat patients with left ventricular aneurysm. There is debate about patient selection and the appropriate surgical technique. We analyzed the results of 102 consecutive patients who underwent left ventricular aneurysmectomy and reconstruction using a modified linear closure technique between 1992 and 2003. The mean age was 62 years, 81% of the patients were male, and 47% had an ejection fraction < 35%. The locations of the left ventricular aneurysms were anteroapical (75%), apical (21%), and posteroinferior (4%); 23% contained thrombi. Additional procedures included aortic valve replacement in 4, mitral valve repair in 1, and coronary bypass grafting in 98 patients; 3 underwent isolated repair of left ventricular aneurysm. Hospital mortality was 7% and long-term survival was 76% at a mean follow-up of 39 months. Most patients improved symptomatically postoperatively. Left ventricular aneurysm repair with tailored scar excision and a modified closure technique is associated with acceptable mortality and long-term survival.
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INTRODUCTION
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Left ventricular aneurysm (LVA) has been defined as any large area of ventricular akinesia or dyskinesia that reduces left ventricular (LV) ejection fraction (EF). It is a complication of acute myocardial infarction, which can lead to congestive heart failure, ventricular arrhythmias, and thromboembolic events. Surgical resection of LVA has been performed since it was first described by Likoff and Bailey1 in 1955. Operative procedures include excision of the aneurysm with linear closure, a pursestring technique, endoventricular circuloplasty, and the endoaneurysmorrhaphy technique.2–5 Most series of LVA surgery have reported symptomatic improvement in the postoperative period with any of these techniques.6–8 Recently, these procedures have been advocated in patients without a discrete aneurysm, as treatment for ischemic cardiomyopathy.6,8 This retrospective study evaluated the clinical outcome of excision of thinned scarred areas of left ventricle with reconstruction accomplished by a modified linear closure, including septoplasty where required.
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PATIENTS AND METHODS
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Between January 1992 and December 2003, 102 consecutive patients underwent LVA surgery. Ages ranged from 39 to 78 years (mean, 62 ± 7.5 years). There were 83 males and 19 females. The indications for surgery included Canadian Cardiovascular Society angina class III and above in 50 patients, New York Heart Association functional class III and above in 55, and ventricular arrhythmias in 2. Thirty patients required urgent surgery and 42 were on diuretics. The EF was good (
50%) in 4%, moderate (35%–49%) in 49%, and poor (< 35%) in 47% of patients. There was associated triple-vessel disease in 71 patients, double-vessel in 18, single-vessel in 12, and left main involvement in 11. The location of the aneurysm was anteroapical in 77 patients, apical in 21, and posteroinferior in 4. Thrombus was present in the aneurysms in 24 patients. Thirty-six patients had grade 2 or 3 mitral regurgitation (MR). Those with > grade 3 MR were not considered for LVA surgery. Associated procedures consisted of coronary artery bypass grafting in 98, aortic valve replacement in 4, and mitral valve repair in one patient. The procedure was performed using cardiopulmonary bypass and moderate systemic hypothermia. With the heart supported on bypass, it was carefully inspected, correlating the findings of preoperative echocardiography and the ventriculogram. If there was doubt about the extent of the infarcted area, aspiration with an 18 gauge needle was performed to ascertain the thinness of the myocardial wall and decide the amount to be resected. The heart was arrested and myocardial protection provided with intermittent antegrade cold blood cardioplegia. The aneurysm was incised parallel to the interventricular septum, and any intracavitary clots were removed. The wall of the aneurysm was palpated and the size, shape, and internal geometry of the LV cavity was evaluated. Excision of the aneurysm was planned to remove as much nonfunctioning myocardial wall as possible. We tried to preserve the left anterior descending artery whenever possible, even if it was involved in the scar, because it may be important as a conduit for collateral circulation and intraoperative myocardial preservation. Any endocardial calcification extending beyond the resection area was stripped off the myocardium to facilitate subsequent approximation of the edges. For modified linear repair, the edges were re-approximated with two strips of Teflon felt for reinforcement on either side, using 2/0 Prolene sutures. It is important to place the sutures in a horizontal mattress fashion through relatively thicker areas of the myocardium, with wider bites on the tissue edges and narrower bites on the felt strips. Tying these sutures leads to longitudinal plication of the ventricular incision and helps to restore the ventricle to a more normal elliptical shape (Figure 1
). A teflon strip was placed on the surface of the opposing ventricular edge, between the two previous strips, and a continuous 2/0 Prolene suture was passed through all layers to further reinforce the repair and secure hemostasis. In 11 cases where the septum was thinned out and scarred, patch septoplasty was carried out by attaching a Dacron sheet to the normal-looking septum on 3 sides, using continuous 3/0 Prolene sutures, and incorporating the anterior edge of this patch in the linear ventricular repair. This excluded the aneurysmal septum from the residual LV cavity. The left anterior artery was grafted in most cases.
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Figure 1. Diagram showing placement of sutures further apart on the tissue edges than on the felt strips, to ensure that the incision is plicated in the closure.
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An attempt was made to bypass all other coronary vessels with significant occlusive disease. The distal coronary anastomoses were performed either before or after repair of the aneurysm, depending on the preference of the surgeon and topography of the vessel. De-airing was carried out through the superior pulmonary vein, aspirating the LV apex, and venting the aortic root.
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RESULTS
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All patients were successfully weaned off cardiopulmonary bypass. The hospital mortality and postoperative morbidity are given in Table 1. There were 7 hospital deaths due to cardiac failure in 5 patients and cerebrovascular accident and gastrointestinal bleeding in one each. Univariate analysis revealed that poor EF ( p = 0.013), preoperative use of diuretics ( p = 0.037), perioperative intra-aortic balloon pump insertion ( p < 0.001), urgent priority ( p = 0.05), and cardiopulmonary time > 2 hr ( p = 0.004) were significantly associated with hospital mortality.
At 60 months, the cumulative survival was 73% (Figure 2), 62% of survivors were free of angina, and 82% were free from re-admission for congestive cardiac failure. Of 20 patients in preoperative functional class IV, 18 improved symptomatically by one or more class; and 31 of 37 patients in class III improved by one or more class (Figure 3). Echocardiography demonstrated increased EF and decreased LV end-diastolic and end-systolic volumes postoperatively (Table 2). Of the 36 patients with significant MR preoperatively, 19 (53%) had a decrease in the degree of MR by at least one grade. Cox regression analysis of various pre- and perioperative variables identified age > 70 years (odds ratio 1.9; 95% confidence interval 1.2 to 2.9) and preoperative diuretic requirement for congestive cardiac failure (odds ratio 1.5; 95% confidence interval 1.1 to 2.6) as adversely affecting long-term survival.
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Figure 2. Kaplan-Meier survival curve after aneurysm resection in 102 patients, figures in parentheses indicate the number of patients at risk at each time point.
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DISCUSSION
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Left ventricular aneurysm distorts the left ventricle to spherical geometry with limited contractile and filling capacity, resulting in congestive cardiac failure, thromboembolism, arrhythmias, and death. Ventricular reduction surgery (surgical ventricular restoration) aims to resect the nonfunctioning LV wall and plicate the length of the incision, thereby decreasing the chamber dimension and restoring the ventricle to a more ellipsoidal shape. Reduction of LV volume has two important effects. First, according to Laplace’s equation (which relates wall stress inversely to wall thickness and directly to chamber radius), volume reduction diminishes wall stress and thereby decreases myocardial oxygen consumption. Minimizing the mass of abnormal myocardium improves wall compliance, reduces filling pressure, and enhances diastolic coronary flow. Second, reduction of wall stress, a critical determinant of afterload, enhances the contractile performance of the ventricle by increasing the extent and velocity of systolic fiber shortening.9 It ultimately enhances the thickness of the remote viable muscle and improves LV function.6 Buckberg10 explained the terms ventricular remodeling and ventricular restoration, and emphasized the need to restore LV shape and volume, which determine prognosis after surgery, independent of EF. It was suggested that patients who develop LVA after myocardial infarction should be followed up closely and offered surgery when the signs of decompensation first appear, such as increasing symptoms on optimal medical management, or evidence of increasing ventricular volume or MR in asymptomatic patients.6 Repair of LVA should be carried out early in the course of the disease; if delayed, contractile function of the remote muscle may deteriorate with a progressive decrease in EF and dilatation of the heart.11,12
Excision of the scar is tailored to leave the left anterior descending artery for revascularization whenever possible, even if the distal vessel has been included in the repair. Revascularization of the left anterior descending artery territory that includes the septum is important in improving the short- and long-term results.6,12,13 In our series, 35% of patients had mild to moderate MR. Those with severe MR were generally too sick to be operated on and have been shown to have high operative mortality and poor long-term outcomes.14 One of our patients underwent mitral valve repair, the others did not undergo any mitral valve procedure; revascularization of the myocardium, the decrease in ventricular and hence annular size, and realignment of papillary muscles and chordae as a consequence of improved LV geometry ultimately improve papillary muscle function and thus MR.6 At follow-up, a decrease in MR by at least one grade was seen in approximately half of the patients with MR before surgery. We now carry out routine transesophageal echocardiography to assess residual MR postoperatively.
The technique of ventricular reconstruction in our series differed from the approach of Dor and colleagues.4 The procedure consisted of resecting the thinned area of left ventricle and closing the ventricle by modified linear plication without a patch. It is a simple, reproducible, and technically easier procedure. We believe that septoplasty should be employed only when a septal aneurysm has occurred. This technique restores a more normal elliptical shape to the distal left ventricle, which may be important in optimizing long-term results. There is less lateral force compared to a spherical ventricle, and the papillary muscles are better aligned for optimal mitral valve function.9
There is still controversy regarding the superiority of endoventricular patch plasty over linear repair. Some studies reported better functional improvement with the former; others failed to demonstrate any difference between the various methods.15–19 No randomized trials have been undertaken to evaluate long-term survival after repair of LVA with various techniques, but some studies demonstrated better long-term survival with patch plasty, and others failed to find any difference between patch plasty and linear repair.15,18–20 We achieved satisfactory results in the form of long-term functional improvement and prolonged survival with the use of scar excision tailored according to individual anatomy and subsequent modified linear closure. The operative mortality of 7% is at the high end of the reported range of 2.6% to 10%.6,9,17,18 Functional improvement was more pronounced in patients who had the most severe symptoms and were in an advanced functional class.14 The 5-year survival of 73% is comparable to reported rates of 58% to 86%.6,15,17 Follow-up echocardiography demonstrated decreased LV chamber dimensions and improved EF, but there was no significant relationship between postoperative EF and functional class, which has also been noted by others.14
There were limitations to this study: we did not have a sufficient number of patients operated on by other methods to compare with this cohort; and as most of our patients underwent revascularization, it is difficult to quantify the contribution of improved myocardial blood supply to the improvement in symptoms. Nevertheless, this study confirms that LVA resection can be carried out with acceptable operative mortality and leads to improvement in symptoms and good long-term survival. We recommend that patients with dyskinetic or akinetic areas of left ventricle should be kept under surveillance and operated on when the first signs and symptoms of decompensation appear. Furthermore, ventricular reconstruction by modified linear closure and septoplasty is relatively easy to perform and adapt.
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REFERENCES
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ABSTRACT
INTRODUCTION
