MMCTS
(April 25, 2005). doi:10.1510/mmcts.2004.000596
Copyright © 2005 European Association for Cardio-thoracic Surgery
Procedure
Left ventricular aneurysm/reshaping techniques
Lorenzo Menicanti* and
Marisa Di Donato
Cardiac Surgery, San Donato Hospital, Via Morandi 30, 20097 San Donato Milanese, Italy
* Corresponding author: * Tel.: +39-02-52774519; fax: +39-02-52774327. E-mail: menicanti{at}libero.it
 |
Summary
|
|---|
Surgical ventricular restoration (SVR) is an emerging technique aiming to restore left ventricular geometry and function in dilated ischemic cardiomyopathy. It applies not only to the classic aneurysm (Type 1) but also to the true ischemic dilated cardiomyopathy (Type 3) and to the intermediate type (Type 2). This type classification based on systolic morphology allows patient selection. SVR is performed under total cardiac arrest with antegrade crystalloid cardioplegia, following complete coronary revascularization, almost always on the left anterior descending artery and mitral repair through ventriculotomy, when needed. Results on more than 1000 patients show that SVR is safe and effective in improving pump function, clinical status and survival in patients with post-infarction ischemic cardiomyopathy.
Key Words: Myocardial infarction • Left ventricular remodeling • Myocardial surgical re-shaping
|
Introduction
|
|---|
Heart failure is an epidemic affecting almost five million people in the United States and costing billions of dollars per year. Ischemic cardiomyopathy as a complication of myocardial infarction is the most common cause of heart failure accounting for up to 70% of the cases. Among them 90% have a myocardial infarction, which results in loss of regional contraction and thereby alters cardiac structure/function relationship. The geometric consequence is loss of the free wall and septum. Current therapeutic advances in the management of acute myocardial infarction (MI) have reduced early mortality but allowed survivors to undergo the process of left ventricular remodeling resulting in the late development of congestive heart failure. According to data from NHLBI, 20% of the survivors of MI develop symptomatic heart failure in 5 years. Despite the availability of multiple drug therapy found efficacious in randomized clinical trials [1], survival with advanced heart failure is estimated at only 50% at 1–2 years after diagnosis.
Cardiac transplantation has a median survival of 10 years but is only an option for few patients due to limited donor supplies.
Surgical restoration of the left ventricular wall (SVR) or surgical re-shaping of the heart, includes operative methods that reduce LV volumes and ‘restore’ elliptical shape and has evolved over a period of more than 20 years [2,3,4,5] as a valid alternative not only to heart transplantation but also to medical therapy alone for treatment of left ventricular remodeling as a result of myocardial infarction and congestive heart failure. Historically it was applied to ‘true’ dyskinetic aneurysm then Dor recognized that the procedure can be safe and effective in both akinetic and dyskinetic scar [2]. The procedure involves placement of an endoventricular patch through ventriculotomy which excludes the scarred/fibrotic tissue and reduces the chamber size [2]. Recent advancements in SVR include the development and application of an endoventricular shaping and sizing device that assists the surgeon in restoring the ventricle to its optimal elliptical shape and size [5].
|
Background
|
|---|
The strict relationship between the form and the function of the heart allows optimal ejection when the form is elliptical and the contraction vector forces are directed towards the outflow tract. Myocites loss following myocardial infarction leads to geometric changes with LV dilatation and spherical aspect (Schematic 1, 2, 3 and Graph 1).
View larger version (48K):
[in this window]
[in a new window]
|
Schematic 1 The 3-D architecture of the heart. The spatial relationship of the double spiral of myocardial fibers and the angles between the two layers are important determinants of cardiac shape. They serve to resist deformation, maintain shape and wall thickness, and prevent ventricular bulging and rupture. This configuration allows a 15% shortening of the fibers to give a global ejection fraction of 60%.
|
|
View larger version (50K):
[in this window]
[in a new window]
|
Schematic 2 The different distribution of the fibers within the wall from the epicardium to the endocardium accounts for the twisting effect of the apex that optimizes the ejection of blood into the aortic vessel. The elliptical shape enhances blood flow at the inflow and outflow tract.
|
|
View larger version (6K):
[in this window]
[in a new window]
|
Schematic 3 When a force is applied at the vertex of the figures it splits into two components: longitudinal and lateral. At an equal longitudinal force the lateral force is much higher if the shape of the vertex is more rounded; i.e. if the radius of curvature is greater.
|
|
View larger version (24K):
[in this window]
[in a new window]
|
Graph 1 The diagram shows the strict relationship between spericity index (short/long axis) on the abscissa and ejection fraction (ordinate). For a given 15% fiber contraction, normal short/long axis is about 0.5 and EF is 62%. At the same fiber contraction EF falls below 40% if the ratio between short to long axis approaches one (sphere) and it goes up to 80% or more if the short to long axis ratio approaches.
|
|
|
Pathophysiology
|
|---|
In almost 30% of the patients, the occlusion of the left anterior descending artery, even when successfully reperfused, leaves a scar tissue in the anterior and septal walls which may be transmural or subendocardial. Early revascularization more often salvaged the epicardial layers but leaves necrosis at the endocardial level (Video 1, Schematics 4, 5 and 6).
Click on image to view video |
Video 1 LV geometric changes following anterior infarction. The anterior and septal walls become thinner; the cavity enlarges and becomes more spherical. The papillary muscles are displaced, which accounts for mitral dysfunctioning.
|
|
View larger version (29K):
[in this window]
[in a new window]
|
Schematic 6 Pre-operative study of LV shape. With the analysis of shape and regional wall motion we were able to identify 3 types of LV silhouettes which differ in shape for the presence of a sharp change in systolic curvature at the antero-basal and infero-basal regions (Type I or classic aneurysm); change in systolic curvature at the infero-basal region (Type II) and loss of systolic curvature changes (Type III). These morphologic types are independent on global EF and the outcome of the patients does not differ significantly between the three types.
|
|
|
Surgical technique
|
|---|
The procedure is conducted under total cardiac arrest with crystalloid or blood-cold antegrade cardioplegia. Complete coronary revascularization is first performed with the internal mammary artery almost always on LAD. Then the ventricle is opened with an incision parallel to the LAD (Photos 1, 2, 3, Schematics 7, 8, Photo 4, Schematic 9, Photos 5 and Videos 2, 3, 4, 5, 6, 7, 8).
View larger version (111K):
[in this window]
[in a new window]
|
Photo 2 The characteristic flattening of anterior wall after the aorta is cross-clamped and the vent is on.
|
|
View larger version (124K):
[in this window]
[in a new window]
|
Photo 3 The ventricle is opened with an incision parallel to LAD, after completion of coronary graftings. Note the endocardial scar and the transitional zone.
|
|
View larger version (60K):
[in this window]
[in a new window]
|
Schematic 7 A sized mannequin (50–60 ml/m2) is inserted during the procedure to allow:
• Position of the new apex
• Maintain the short to long axis ratio within more normal value (0.54)
• Give a more elliptical shape
• Leave a normal residual chamber size
• Re-approach papillary muscles
|
|
View larger version (66K):
[in this window]
[in a new window]
|
Schematic 8 The endoventricular circular suture (Fontan stitch) is performed following the curvature of the mannequin and then tightened over the mannequin to leave a not too small cavity.
|
|
View larger version (88K):
[in this window]
[in a new window]
|
Photo 4 The patch (Dacron) is tailored to close the opening of the ventricle with an oval shape. If the opening is less than 3 cm, the opening is closed with a direct suture. The patch is positioned within the cavity, excluding the scarred/fibrotic tissue.
|
|
View larger version (64K):
[in this window]
[in a new window]
|
Schematic 9 The patch is oriented obliquely towards the upper part of the septum and towards the aorta, to allow a more elliptical shape and optimizing ejection. The suture of the patch starts at the septum level and goes towards the apex in an everting way, while the mannequin is inside.
|
|
View larger version (115K):
[in this window]
[in a new window]
|
Photo 5 The mannequin is removed and the patch suture is completed. Note the obliquity of the patch inside the cavity towards the septum.
|
|
Click on image to view video |
Video 2 View of the ventricle as it appears after completion of CABG.
|
|
Click on image to view video |
Video 3 The mannequin is inflated at 50 ml/m2 and inserted into the ventricle.
|
|
Click on image to view video |
Video 4 Inferior plication is started to reduce infero-apical dilatation and to lift up the new apex.
|
|
Click on image to view video |
Video 5 The circular endoventricular suture (Fontan stitch) begins from the apex reference stitch, goes deep into the septum towards the aorta, to the lateral and anterior wall and back to join the new apex.
|
|
Click on image to view video |
Video 6 The mannequin is re-inserted to tighten the circular suture on it, thus avoiding a too small residual cavity.
|
|
Click on image to view video |
Video 7 The patch is tailored with an oval shape and sutured in an everting way at the level of the circular suture. The mannequin is inside to help the correct position of the patch.
|
|
Click on image to view video |
Video 8 The final portion of the suture is performed over the mannequin which is then deflated and removed to complete the closure of the ventricle. Note that the patch is positioned obliquely in respect to the septum, to obtain an elliptical shape.
|
|
Videos 9 and 10 show pre- and post-operative LV angiography in the 68-year-old male patient.
Click on image to view video |
Video 9 Left ventricular angiography in right and left anterior oblique projection is shown before surgery. Note the dilated, spherical shape of the ventricle and the diffuse, severe hypokinesia with akinesia of the septum. Mitral regurgitation is moderate.
|
|
Click on image to view video |
Video 10 Post-operative LV angiograms in the same projections. Note the reduction of volume and the improvement of shortening in the remote regions (inferior and lateral) and in the non-excluded septum. Mitral regurgitation is no longer present.
|
|
Two crucial issues of the procedure are:
A residual too-small cavity which may result in a low cardiac output syndrome and a residual box-like shape which may result in diastolic dysfunction. The first issue is overcome with the use of the mannequin filled at 50–60 ml/m2; the second is linked to a wrong position of the patch (see Schematic 10).
View larger version (45K):
[in this window]
[in a new window]
|
Schematic 10 Example of a residual box-like. Notice the endoventricular circular suture at the level of the transitional zone that brings a wrong position of the patch (parallel to the mitral plane).
|
|
|
Results
|
|---|
Since 1998 we have performed ventricular restoration in 1200 patients. Analysis of pre- and post-operative LV function is available in 630 patients. Characteristics of patients are reported in Table 1.
Global operative mortality rate was 7.2% and went from 3.5 in patients with pre-op EF >40% to 16% in patients with EF 20% and NYHA class IV.
Average operative mortality for isolated SVR plus CABG was 5.6%; associate mitral repair/replacement increase mortality up to 15%. Mitral procedure is an independent predictor of operative mortality with a three times increased risk (logistic regression analysis).
An example of pre- and post-operative TEE echo is reported in Photo 6. The TEE short axis view in the same patient is reported in Photo 7.
View larger version (52K):
[in this window]
[in a new window]
|
Photo 6 Note the pre-op spherical shape and the enlargement of the cavity. After surgery the shape is more elliptical and the size of the ventricle is reduced.
|
|
Table 2 shows hemodynamic results according to pre-op EF.
Overall results show an improvement in pump function, in NYHA functional class and survival [6] (see Graph 2).
View larger version (13K):
[in this window]
[in a new window]
|
Graph 2 Kaplan Meyer survival curve in a cohort of 130 patients operated on between July 2001 and March 2004.
|
|
Mitral repair and surgical ventricular restoration
Functional ischemic mitral regurgitation (MR) frequently complicates ischemic cardiomyopathy and heavily affects survival [7,8].
When the degree of MR is severe or when it is moderate but the annulus is dilated >36 mm and/or ventricular function is severely depressed, we use to repair the mitral valve during SVR procedure.
The repair is performed from the ventricular opening with reduction of the posterior annulus. A double arm stitch is performed from trigone to trigone imbedding the two arms of the suture in the posterior part of the mitral annulus and tightened on a 26–27 mm sizer [9] (Schematic 11 and Video 11).
Click on image to view video |
Video 11 Mitral leaflets and papillary muscles are exposed from the ventricular opening. The trigons are shown and the two arms of the sutures are imbedded in the posterior components of the mitral annulus. Note the sizer to restrict the annulus (26 mm).
|
|
Possible surgical pitfalls
- Incorrect indications
- Incomplete revascularization
- Embolism
- Cavity dimension: too large or too small
- Cavity shape: spherical
- Significant mitral regurgitation
|
Comment
|
|---|
Post-infarction LV aneurysm, either akinetic or dyskinetic is a serious disorder that can lead to congestive heart failure (CHF) and poor prognosis. Surgical treatment is indicated in established cases of CHF, severe angina and malignant ventricular arrhythmias. The goal of surgical intervention is to correct the size and geometry of the LV, reduce wall tension and improve pump function, functional status and survival. Aneurysmectomy and linear repair of the LV was introduced by Cooley in 1958 and remained the standard technique until the late 1980s. Endoventricular circular patch plasty (EVCPP) was then introduced as a more physiologic repair than the linear closure technique [2] especially when the scar extends to the septum. However, there is still controversy whether EVCPP is superior to simple linear resection on early and late outcome. Simple linear closure reduces only the aneurysm of the free wall, while the newer technique targets also the septal component of the aneurysm. A recent paper by Lundblad [10] demonstrated that surgical risk is lower and long term survival is higher after EVCPP than simple linear repair. However, other results failed to demonstrate a superiority of the patch plasty [11].
No randomized studies exist on SVR vs other surgical approach to LV aneurysm, the technique is not standardized and the patient population largely varies in the reported series, which are often small. The largest reported series is from the RESTORE team (Reconstructive Endoventricular Surgery returning Torsion Original Radius Elliptical Shape) [12]. A summary of the results obtained with SVR is reported in Table 3. Only data with at least 50 patients treated with SVR published in peer journals have been considered. The data, although incomplete, show a uniform increase in EF and a significant reduction in end systolic volume index. Operative mortality varies from 2.8 to 11% likely reflecting largely different patient population, different definition of aneurysm, different operative techniques and different eras. Five-year survival, when reported, is high (range 68–95%) in this high risk population with pre-op EF ranging between 25 and 35%.
In conclusion, SVR is a ventricular reconstruction strategy for patients with heart failure that applies not only to the classic aneurysm but also to dilated cardiomyopathy without demarcation (neck) and to akinetic myocardium [19,20]. The procedure has proven to be safe and effective in the treatment of ischemic cardiomyopathy following myocardial infarction. The results from different centers are rather uniform in terms of pump function and survival improvement. Operative mortality rate is significantly higher when mitral repair is associated to CABG and SVR. Recently, Hernandez reported at the American Heart Association the outcome of 538 patients who underwent the procedure between 2002 and 2003 at 118 of the 600 hospitals that participated in the STS national database. The 30 days mortality was 9.3% in this cohort. Procedural mortality rates by volume showed that those centers performing less than 5 procedures had a rate of 12.5%, compared with 7.3% in centers performing 10 or more. Since all the reported data are observational we need to wait for the end of the multicenter randomized STICH trial (Surgical Treatment for Ischemic Heart Failure) that will definitely assess if adding ventricular restoration to CABG will give benefit in terms of survival free of hospitalization.
|
References
|
|---|
- Packer M, Bristow MR, Cohn JN, Colucci WS, Fowler MB, Gilbert EM, Shusterman NH. The effect of carvedilol on morbidity and mortality in patients with chronic heart failure. U.S. Carvedilol Heart Failure Study Group. N Engl J Med 1996;334:1349–1355.[Abstract/Free Full Text]
- Dor V, Sabatier M, Di Donato M, Montiglio F, Toso A, Maioli M. Efficacy of endoventricular patch plasty in large postinfarction akinetic scar and severe left ventricular dysfunction: comparison with a series of large dyskinetic scars. J Thorac Cardiovasc Surg 1998;116:50–59.[Abstract/Free Full Text]
- Athanasuleas CL, Stanley AW Jr, Buckberg GD, Dor V, Di Donato M, Blackstone EH. Surgical anterior ventricular endocardial restoration (SAVER) in the dilated remodeled ventricle after anterior myocardial infarction. RESTORE group. Reconstructive endoventricular surgery, returning Torsion Original Radius Elliptical Shape to the LV. J Am Coll Cardiol 2001;37:1199–1209.[Abstract/Free Full Text]
- Menicanti L, Di Donato M. The Dor procedure: what has changed after fifteen years of clinical practice? J Thorac Cardiovasc Surg 2002;124:886–890.[Free Full Text]
- Strobeck J, Di Donato M, Costanzo MR, Conte J, Boyce S. Importance of shape and surgically reshaping the left ventricle in ischemic cardiomyopathy. Congest Heart Fail 2004;10:45–53.[Medline]
- Di Donato M, Toso A, Maioli M, Sabatier M, Stanley AW Jr, Dor V. Intermediate survival and predictors of death after surgical ventricular restoration. Semin Thorac Cardiovasc Surg 2001;13(4):468–475.[Medline]
- Lamas GA, Mitchell GF, Flaker GC, Smith SC Jr, Gersh BJ, Basta L, Moye L, Braunwald E, Pfeffer MA. Clinical significance of mitral regurgitation after acute myocardial infarction. Circulation 1997;96:827–833.[Abstract/Free Full Text]
- Yiu SF, Enriquez-Sarano M, Tribouilloy C, Seward JB, Tajik AJ. Determinants of the degree of functional mitral regurgitation in patients with systolic left ventricular dysfunction: a quantitative clinical study. Circulation 2000;102:1400–1406.[Abstract/Free Full Text]
- Menicanti L, Di Donato M, Frigiola A, Buckberg G, Santambrogio C, Ranucci M, Santo D; RESTORE Group. Ischemic mitral regurgitation: intraventricular papillary muscle imbrication without mitral ring during left ventricular restoration. J Thorac Cardiovasc Surg 2002;123:1041–1050.[Abstract/Free Full Text]
- Lundblad R, Abdelnoor M, Svennevig JL. Surgery for left ventricular aneurysm: early and late survival after simple linear repair and endoventricular patch plasty. J Thorac Cardiovasc Surg 2004;128:449–456.[Abstract/Free Full Text]
- Doss M, Martens S, Sayour S, Hemmer W. Long term follow up of left ventricular function after repair of left ventricular aneurysm. A comparison of linear closure versus patch plasty. J Thorac Cardiovasc Surg 2001;20:783–785.
- Athanasuleas CL, Buckberg GD, Stanley AW, Siler W, Dor V, Di Donato M, Menicanti L, Almeida de Oliveira S, Beyersdorf F, Kron IL, Suma H, Kouchoukos NT, Moore W, McCarthy PM, Oz MC, Fontan F, Scott ML, Accola KA; RESTORE group. Surgical ventricular restoration in the treatment of congestive heart failure due to post-infarction ventricular dilation. J Am Coll Cardiol 2004;44:1439–1445.[Abstract/Free Full Text]
- Dor V. Left ventricular reconstruction for ischemic cardiomyopathy. J Card Surg 2002;17:180–187.[Medline]
- Mikleborough LL, Merchant N, Ivanov J, Rao V, Carson S. Left ventricular reconstruction: early and late results. J Thorac Cardiovasc Surg 2004;128:27–37.[Abstract/Free Full Text]
- Rogers WJ, Oberman A, Kouchoukos NT. Left ventricular aneurysmectomy in patients with single vs multivessel coronary artery disease. Circulation 1978;58(3 Pt 2):I50–I56.[Medline]
- Di Mattia DG, Di Biasi P, Salati M, Mangini A, Fundaro P, Santoli C. Surgical treatment of left ventricular post-infarction aneurysm with endoventriculoplasty: late clinical and functional results. Eur J Cardiothorac Surg 1999;15:413–418.[Abstract/Free Full Text]
- Cirillo M, Amaducci A, Brunelli F, Dalla Tomba M, Parrella P, Tasca G, Troise G, Quaini E. Determinants of postinfarction remodeling affect outcome and left ventricular geometry after surgical treatment of ischemic cardiomyopathy. J Thorac Cardiovasc Surg 2004;127:1648–1656.[Abstract/Free Full Text]
- Calafiore AM, Gallina S, Di Mauro M, Pano M, Teodori G, Di Giammarco G, Contini M, Iaco AL, Vitolla G. Left ventricular aneurysmectomy: endoventricular circular patch plasty or septo-exclusion. J Card Surg 2003;18:93–100.[CrossRef][Medline]
- Di Donato M, Sabatier M, Dor V, Toso A, Maioli M, Fantini F. Akinetic versus dyskinetic postinfarction scar: relation to surgical outcome in patients undergoing endoventricular circular patch plasty repair. J Am Coll Cardiol 1997;29:1569–1575.[Abstract]
- Buckberg GD. Defining the relationship between akinesia and dyskinesia and the cause of left ventricular failure after anterior infarction and reversal of remodeling to restoration. J Thorac Cardiovasc Surg 1998;116:47–49.[Free Full Text]
This article has been cited by other articles:
|
|
|
|
 
D. Lindblom, A. Albage, and U. Sartipy
Surgery for ventricular tachycardia in patients undergoing surgical ventricular restoration
MMCTS,
December 17, 2007;
2007(1217):
2816.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
Top
Summary
Introduction
