**3.1 Assessment of cardiac geometry and regional function of the LV**

Two-dimensional echocardiography was used to evaluate cardiac geometry, including dimensions and LV volume, valvular morphology, and the subvalvular apparatus. As indices of LV volume, the LV end-systolic and end-diastolic volume indices (LVESVI and LVEDVI) were calculated.

Regional LV function was examined by cardiac magnetic resonance imaging (MRI)15,16) and color kinesis echocardiography17). Regional LV strain was assessed by speckle-tracking echocardiography under normal and dobutamine-stress conditions18).

a. Cardiac MRI

Cardiac MRI is a medical imaging technology for the non-invasive assessment of cardiac structure and function. Although it shows the precise myocardial anatomy in normal hearts, it is also useful for post-ischemic myocardial assessment15,16). To investigate LV wall motion, MRI images were obtained by cine acquisition. The depth and extension of the scarred LV wall were evaluated with 4 MRI projections. The 4-chamber view was used to assess the septum and lateral wall. The 2-chamber view (the vertical long-axis view) was useful for the anterior and posterior walls of the LV. The 3-chamber view (the LV outflow tract view) provided a detailed analysis of the mitral subvalvular apparatus. The short-axis view enabled a staged analysis of the septum and papillary muscles. Late gadolinium enhancement was also performed to investigate the irreversible myocardium of the LV wall19).

b. Color kinesis echocardiography

Color kinesis is a non-invasive technology for the echocardiographic assessment of LV wall motion based on acoustic quantification17). This technique automatically detects endocardial motion in real time using integrated backscatter data to identify pixel transitions from blood to tissue during systole on a frame-by-frame basis. We have reported the usefulness of intraoperative color kinesis echocardiography under cardiopulmonary bypass (CPB) assist for patients with idiopathic dilated cardiomyopathy20). LV wall motion was observed by direct vision of the cardiac echogram (HP SONO 5500; Agilent Technologies, Palo Alto, CA, USA) under different preloads controlled by CPB (volume reduction test). The objective of this test was to assess the akinetic region of the LV wall for SVR.

c. Speckle-tracking echocardiography

Speckle-tracking echocardiography is a unique imaging technique that analyzes multidirectional components of LV deformation within an ultrasonic window by tracking interference patterns and natural acoustic reflections21). The tracking system is obtained by automatic measurement of the distance between 2 pixels of an LV segment during the cardiac cycle, independent of the angle of insonation22,23).

Echocardiography was carried out using a Vivid 7 ultrasonography machine (GE Medical Systems, Milwaukee, WI, USA) with an M3S probe. Short-axis images from the mid-level (i.e., papillary muscle level) of the LV were obtained from the parasternal window to assess myocardial segmental viability and LV dyssynchrony. Caution was exercised to ensure

heart failure and worsening multiorgan failure, an emergent operation was performed in 12

Two-dimensional echocardiography was used to evaluate cardiac geometry, including dimensions and LV volume, valvular morphology, and the subvalvular apparatus. As indices of LV volume, the LV end-systolic and end-diastolic volume indices (LVESVI and

Regional LV function was examined by cardiac magnetic resonance imaging (MRI)15,16) and color kinesis echocardiography17). Regional LV strain was assessed by speckle-tracking

Cardiac MRI is a medical imaging technology for the non-invasive assessment of cardiac structure and function. Although it shows the precise myocardial anatomy in normal hearts, it is also useful for post-ischemic myocardial assessment15,16). To investigate LV wall motion, MRI images were obtained by cine acquisition. The depth and extension of the scarred LV wall were evaluated with 4 MRI projections. The 4-chamber view was used to assess the septum and lateral wall. The 2-chamber view (the vertical long-axis view) was useful for the anterior and posterior walls of the LV. The 3-chamber view (the LV outflow tract view) provided a detailed analysis of the mitral subvalvular apparatus. The short-axis view enabled a staged analysis of the septum and papillary muscles. Late gadolinium enhancement was also performed to investigate the irreversible myocardium of the LV

Color kinesis is a non-invasive technology for the echocardiographic assessment of LV wall motion based on acoustic quantification17). This technique automatically detects endocardial motion in real time using integrated backscatter data to identify pixel transitions from blood to tissue during systole on a frame-by-frame basis. We have reported the usefulness of intraoperative color kinesis echocardiography under cardiopulmonary bypass (CPB) assist for patients with idiopathic dilated cardiomyopathy20). LV wall motion was observed by direct vision of the cardiac echogram (HP SONO 5500; Agilent Technologies, Palo Alto, CA, USA) under different preloads controlled by CPB (volume reduction test). The objective of this test

Speckle-tracking echocardiography is a unique imaging technique that analyzes multidirectional components of LV deformation within an ultrasonic window by tracking interference patterns and natural acoustic reflections21). The tracking system is obtained by automatic measurement of the distance between 2 pixels of an LV segment during the

Echocardiography was carried out using a Vivid 7 ultrasonography machine (GE Medical Systems, Milwaukee, WI, USA) with an M3S probe. Short-axis images from the mid-level (i.e., papillary muscle level) of the LV were obtained from the parasternal window to assess myocardial segmental viability and LV dyssynchrony. Caution was exercised to ensure

**3.1 Assessment of cardiac geometry and regional function of the LV** 

echocardiography under normal and dobutamine-stress conditions18).

patients (14%).

**3. Materials and methods** 

LVEDVI) were calculated.

b. Color kinesis echocardiography

c. Speckle-tracking echocardiography

was to assess the akinetic region of the LV wall for SVR.

cardiac cycle, independent of the angle of insonation22,23).

a. Cardiac MRI

wall19).

short-axis images with circular cross-sections and minimal out-of-plane movement. Shortaxis images were analyzed by the EchoPAC platform (2DS software package, version 7; GE Medical Systems), which uses a speckle-tracking technique to derive rotation and strain for selected regions of the myocardium24). LV torsion is also calculated automatically from the LV basal and apical rotation data in the platform. For assessing segmental myocardial viability, the myocardial region obtained from the short-axis images of the midlevel LV was divided into four segments (septal, anterolateral, posterior, inferoseptal), and the circumferential strain profile was analyzed, which is closely related to myocardial viability25,26).

Fig. 1. Late gadolinium enhancement of cardiac magnetic resonance imaging (in the left panel) and two-dimensional speckle-tracking echocardiographic imaging (in the right panel) in a representative case with ischemic cardiomyopathy. Severe ischemic injury and a suggestion of fibrotic change (a tissue characteristic) are depicted in the lateral, posterior, and inferoseptal segments by late gadolinium enhancement, while end-systolic circumferential strain of speckle-tracking echocardiographic imaging detected nearly +20% lengthening at the posterior region only (shown as dark blue). Two-dimensional speckletracking echocardiography could identify such transmurally injured "dyskinetic scars" (a mechanodynamic myocardial property), which is critically important in ventricular restoration tactics.

#### d. Prediction of the non-functional akinetic region of the LV

Using these results, the exclusion area of non-functional myocardium for SVR was predicted preoperatively. A representative case with ICM is shown in **Fig. 1**. On the left side, late gadolinium enhancement of cardiac MRI demonstrated regional stains on the endocardium in the lateral, posterior, and infero-septal segments. On the right side, two-dimensional speckle-tracking echocardiography revealed LV torsion at the corresponding short-axis slice level seen on cardiac MRI. Severe ischemic injury and suggestions of fibrotic change (a tissue characteristic) were depicted by cardiac MRI, while end-systolic circumferential strain of speckle-tracking echocardiographic imaging detected nearly +20% lengthening at the posterior region only (shown as dark blue). Thus, two-dimensional speckle-tracking echocardiography could identify such transmurally injured "dyskinetic scars" (a

Surgical Ventricular Restoration for Ischemic Cardiomyopathy with Functional Mitral Regurgitation 87

(D) (E)

Fig. **2A**. The schema shows the heart with ICM including the antero-apical akinetic region. **2B.** The antero-apical LV wall is opened in the center of the region. The margin of the contractile myocardium around the scar, the so-called "contractility trail", is observed through the ventriculotomy. **2C.** To plicate the circular defect of the LV muscle, 2-0 polypropylene purse-string suture is placed around the entire circumference of the

contractility trail. **2D.** A collagen-impregnated Dacron knitted fabric (approximate 3×4 cm) is placed over the plicated defect of the myocardium and fixed with 2-0 polypropylene running suture after deaeration of the LV. **2E.** Two felt strips are placed along the

ventriculotomy on each side, and the excluded external scar is folded to reinforce the suture line with 2-0 polypropylene horizontal mattress sutures with a large needle. The line is

secured by double 2-0 polypropylene over-and-over sutures from both ends.

(A) (B) (C)

mechanodynamic myocardial property), which are critically important in ventricular restoration tactics.

#### **3.2 Technical details of our three SVR procedures for ICM**

Surgical resection is the oldest and simplest technique for LV aneurysm following myocardial infarction. At the end of the 1970s, SVR with patchplasty had been reported for the posterior and anterior regions of the LV27,28). In 1980s, Dor and associates established a new surgical technique with a circular patch (endoventricular circular patch plasty; EVCCP) for antero-septo-apical aneurysms29). Around the same time, Cooley reported ventricular endoaneurysmorrhaphy with an elliptical patch to allow prompt recovery and restoration of ventricular function30). As Hutchins and coworkers suggested the importance of cardiac geometry after SVR, cardiac surgeons modified their technique to obtain a postoperative elliptical shape of the LV31). Recently, we have developed new techniques of septal anterior ventricular exclusion (SAVE) for the anterior wall of the LV and a posterior restoration procedure (PRP) for the posterior wall in patients with dilated cardiomyopathy8,24). We performed SVR with three different procedures (EVCPP, SAVE, and PRP) for patients with ICM, and the details of our modified techniques are described below.

a. Modified endoventricular circular patch plasty (EVCPP)

The presence of an antero-septo-apical akinetic region is a good indication for EVCPP, as reported by Dor and coworkers29). At first, coronary revascularization was completely performed under blood cardioplegic cardiac arrest. Valvular surgery, including mitral, tricuspid, and aortic valves, was completed prior to EVCPP. To obtain a better surgical field of the anterior LV wall, two 1-0 silk sutures were placed at the apex (**Fig. 2A**). The anteroapical LV wall was opened in the center of the akinetic region (**Fig. 2B**). When thrombus formation was detected in the LV trabeculation, it was entirely removed. The anatomical margin of the contractile myocardium around the scar, the so-called "contractility trail", was observed through the ventriculotomy. To prevent late ventricular tachycardia or fibrillation (VT/VF), cryoablation was performed on the viable LV myocardium along the junction. To plicate the circular defect of the LV muscle, 2-0 polypropylene purse-string suture (Prolene®; Ethicon, Somerville, NJ, USA) was placed around the entire circumference of the contractility trail (**Fig. 2C**). Then, a collagen-impregnated Dacron knitted fabric (MAQUET Cardiovascular LLC, Wayne, NJ, USA) (approximately 3×4 cm) was placed over the plicated defect of the myocardium and fixed with 2-0 polypropylene running suture after deaeration of the LV (**Fig. 2D**). Finally, two felt strips were placed along the ventriculotomy on each side, and the excluded external scar was folded to reinforce the suture line with 2-0 polypropylene horizontal mattress sutures with a large needle (Matsuda-ika Kogyo, Tokyo, Japan). The line was secured by double 2-0 polypropylene over-and-over sutures from both ends (**Fig. 2E**).

#### b. Septal anterior ventricular exclusion (SAVE)

The presence of a large antero-septal akinetic region is a good indication for SAVE or the Pacopexy technique developed by Isomura et al8,12). As for EVCPP, complete coronary revascularization was first preformed under blood cardioplegic arrest. Valvular surgery, including mitral, tricuspid, and aortic valves, was undertaken prior to SAVE. The aortic crossclamp was released to allow the heart to start beating, and perfusion pressure was

mechanodynamic myocardial property), which are critically important in ventricular

Surgical resection is the oldest and simplest technique for LV aneurysm following myocardial infarction. At the end of the 1970s, SVR with patchplasty had been reported for the posterior and anterior regions of the LV27,28). In 1980s, Dor and associates established a new surgical technique with a circular patch (endoventricular circular patch plasty; EVCCP) for antero-septo-apical aneurysms29). Around the same time, Cooley reported ventricular endoaneurysmorrhaphy with an elliptical patch to allow prompt recovery and restoration of ventricular function30). As Hutchins and coworkers suggested the importance of cardiac geometry after SVR, cardiac surgeons modified their technique to obtain a postoperative elliptical shape of the LV31). Recently, we have developed new techniques of septal anterior ventricular exclusion (SAVE) for the anterior wall of the LV and a posterior restoration procedure (PRP) for the posterior wall in patients with dilated cardiomyopathy8,24). We performed SVR with three different procedures (EVCPP, SAVE, and PRP) for patients with ICM, and the details of our modified techniques are described

The presence of an antero-septo-apical akinetic region is a good indication for EVCPP, as reported by Dor and coworkers29). At first, coronary revascularization was completely performed under blood cardioplegic cardiac arrest. Valvular surgery, including mitral, tricuspid, and aortic valves, was completed prior to EVCPP. To obtain a better surgical field of the anterior LV wall, two 1-0 silk sutures were placed at the apex (**Fig. 2A**). The anteroapical LV wall was opened in the center of the akinetic region (**Fig. 2B**). When thrombus formation was detected in the LV trabeculation, it was entirely removed. The anatomical margin of the contractile myocardium around the scar, the so-called "contractility trail", was observed through the ventriculotomy. To prevent late ventricular tachycardia or fibrillation (VT/VF), cryoablation was performed on the viable LV myocardium along the junction. To plicate the circular defect of the LV muscle, 2-0 polypropylene purse-string suture (Prolene®; Ethicon, Somerville, NJ, USA) was placed around the entire circumference of the contractility trail (**Fig. 2C**). Then, a collagen-impregnated Dacron knitted fabric (MAQUET Cardiovascular LLC, Wayne, NJ, USA) (approximately 3×4 cm) was placed over the plicated defect of the myocardium and fixed with 2-0 polypropylene running suture after deaeration of the LV (**Fig. 2D**). Finally, two felt strips were placed along the ventriculotomy on each side, and the excluded external scar was folded to reinforce the suture line with 2-0 polypropylene horizontal mattress sutures with a large needle (Matsuda-ika Kogyo, Tokyo, Japan). The line was secured by double 2-0 polypropylene over-and-over sutures from both

The presence of a large antero-septal akinetic region is a good indication for SAVE or the Pacopexy technique developed by Isomura et al8,12). As for EVCPP, complete coronary revascularization was first preformed under blood cardioplegic arrest. Valvular surgery, including mitral, tricuspid, and aortic valves, was undertaken prior to SAVE. The aortic crossclamp was released to allow the heart to start beating, and perfusion pressure was

**3.2 Technical details of our three SVR procedures for ICM** 

a. Modified endoventricular circular patch plasty (EVCPP)

restoration tactics.

below.

ends (**Fig. 2E**).

b. Septal anterior ventricular exclusion (SAVE)

Fig. **2A**. The schema shows the heart with ICM including the antero-apical akinetic region. **2B.** The antero-apical LV wall is opened in the center of the region. The margin of the contractile myocardium around the scar, the so-called "contractility trail", is observed through the ventriculotomy. **2C.** To plicate the circular defect of the LV muscle, 2-0 polypropylene purse-string suture is placed around the entire circumference of the contractility trail. **2D.** A collagen-impregnated Dacron knitted fabric (approximate 3×4 cm) is placed over the plicated defect of the myocardium and fixed with 2-0 polypropylene running suture after deaeration of the LV. **2E.** Two felt strips are placed along the ventriculotomy on each side, and the excluded external scar is folded to reinforce the suture line with 2-0 polypropylene horizontal mattress sutures with a large needle. The line is secured by double 2-0 polypropylene over-and-over sutures from both ends.

Surgical Ventricular Restoration for Ischemic Cardiomyopathy with Functional Mitral Regurgitation 89

ends.

(A) (B) (C)

(D) (E) (F)

Fig. **3A**. The schema shows the heart with ICM including a large antero-septal akinetic region. **3B.** The antero-lateral LV wall is opened along the left descending artery from the apex toward the base. **3C.** Multiple 0 braided polyester horizontal mattress sutures with pledgets are placed along the exclusion line of the septum, in a direction that proceeds from the apex to a septal site 1-2 cm below the aortic valve. **3D.** A collagen-impregnated Dacron knitted fabric (approximate 3×4 cm) is placed over the plicated defect of the myocardium and fixed with 2-0 polypropylene running suture. The last two sutures on the apex side are tied after deaeration of the LV. **3E.** Two felt strips are placed along the ventriculotomy on each side, and the excluded external scar is folded to reinforce the suture line with 2-0 polypropylene horizontal mattress sutures anchoring the allowance of Dacron fabric. **3F.** The suture line is secured by double 2-0 polypropylene over-and-over sutures from both

kept >75 mmHg to ensure ongoing coronary perfusion. Thus, the SAVE operation was usually performed on the beating heart. During beating, the transitional zone between the scar and the viable myocardium was easily detected by direct manipulation of the LV muscle.

Two 1-0 silk sutures were placed at the apex to achieve a better surgical field (**Fig. 3A**). The anterior wall of the LV was opened along the left anterior descending artery from the apex toward the base (**Fig. 3B**). Cryoablation was performed on the viable LV myocardium along the incision to prevent late VT/VF. For patients with a dilated posterior wall between two papillary muscles, chordal cutting of the basal chordae and papillary muscle approximation was performed via this incision (see *Technical details of our mitral valve surgery*). Multiple 0 braided polyester horizontal mattress sutures (Ticron®; Tyco, Waltham, MA, USA) with pledgets were placed along the exclusion line of the septum, in a direction that proceeded from the apex to a septal site 1-2 cm below the aortic valve (**Fig. 3C**). A collagenimpregnated Dacron knitted fabric was trimmed to create an elliptical shape, approximately 3×8 cm, and placed along the site of the exclusion, with sutures placed 1 cm from the patch edge to leave a patch rim outside these sutures. The last two sutures were tied after deaeration of the LV (**Fig. 3D**). Finally, two felt strips were placed along the ventriculotomy on each side, and the excluded external scar was folded to reinforce the suture line with 2-0 polypropylene horizontal mattress sutures anchoring the allowance of Dacron fabric **(Fig. 3E)**. The suture line was secured by double 2-0 polypropylene over-and-over sutures from both ends (**Fig. 3F**).

Some patients requiring SAVE were treated by overlapping cardiac volume reduction operations in this series32).

c. Posterior restoration procedure (PRP)

The posterior akinetic region of the LV was repaired with the PRP procedure developed by Isomura et al24). One of the most important operative concepts was the postoperative elliptical shape of the LV. To achieve the elliptical shape, the LV apex and bilateral papillary muscles were preserved in this operation.

As for EVCPP and SAVE, complete coronary revascularization was first preformed under blood cardioplegic arrest. Valvular surgery, including mitral, tricuspid, and aortic valves, was undertaken prior to PRP. PRP was also performed in a beating heart as for the SAVE procedure. Two 1-0 silk sutures were placed at the apex. The akinetic region was opened 1 cm proximal from the apex on the posterior wall between bilateral papillary muscles (**Fig. 4A**). The incision was extended toward the base of the heart, reaching 1 cm above the mitral annulus (**Fig. 4B**). Cryoablation was performed on the viable LV myocardium along the incision to prevent late VT/VF, especially for the LV muscle between the end of the incision and the mitral annulus. Multiple 0 braided polyester horizontal mattress sutures with pledgets were placed along the exclusion line on the viable LV myocardium (**Fig. 3C**). As for the SAVE procedure, a collagen-impregnated Dacron knitted fabric was trimmed to create an elliptical shape and placed over the exclusion with a 1-cm allowance for LV closure. The last two sutures on the apex side were tied after deaeration of the LV (**Fig. 4D**). Finally, the LV was closed in a similar manner as in the SAVE procedure, and the bilateral papillary muscles were approximated during the PRP procedure (**Fig. 4E**). The line was secured by double 2-0 polypropylene over-and-over sutures from both ends (**Fig. 4F**).

kept >75 mmHg to ensure ongoing coronary perfusion. Thus, the SAVE operation was usually performed on the beating heart. During beating, the transitional zone between the scar and the viable myocardium was easily detected by direct manipulation of the LV

Two 1-0 silk sutures were placed at the apex to achieve a better surgical field (**Fig. 3A**). The anterior wall of the LV was opened along the left anterior descending artery from the apex toward the base (**Fig. 3B**). Cryoablation was performed on the viable LV myocardium along the incision to prevent late VT/VF. For patients with a dilated posterior wall between two papillary muscles, chordal cutting of the basal chordae and papillary muscle approximation was performed via this incision (see *Technical details of our mitral valve surgery*). Multiple 0 braided polyester horizontal mattress sutures (Ticron®; Tyco, Waltham, MA, USA) with pledgets were placed along the exclusion line of the septum, in a direction that proceeded from the apex to a septal site 1-2 cm below the aortic valve (**Fig. 3C**). A collagenimpregnated Dacron knitted fabric was trimmed to create an elliptical shape, approximately 3×8 cm, and placed along the site of the exclusion, with sutures placed 1 cm from the patch edge to leave a patch rim outside these sutures. The last two sutures were tied after deaeration of the LV (**Fig. 3D**). Finally, two felt strips were placed along the ventriculotomy on each side, and the excluded external scar was folded to reinforce the suture line with 2-0 polypropylene horizontal mattress sutures anchoring the allowance of Dacron fabric **(Fig. 3E)**. The suture line was secured by double 2-0 polypropylene over-and-over sutures from

Some patients requiring SAVE were treated by overlapping cardiac volume reduction

The posterior akinetic region of the LV was repaired with the PRP procedure developed by Isomura et al24). One of the most important operative concepts was the postoperative elliptical shape of the LV. To achieve the elliptical shape, the LV apex and bilateral papillary

As for EVCPP and SAVE, complete coronary revascularization was first preformed under blood cardioplegic arrest. Valvular surgery, including mitral, tricuspid, and aortic valves, was undertaken prior to PRP. PRP was also performed in a beating heart as for the SAVE procedure. Two 1-0 silk sutures were placed at the apex. The akinetic region was opened 1 cm proximal from the apex on the posterior wall between bilateral papillary muscles (**Fig. 4A**). The incision was extended toward the base of the heart, reaching 1 cm above the mitral annulus (**Fig. 4B**). Cryoablation was performed on the viable LV myocardium along the incision to prevent late VT/VF, especially for the LV muscle between the end of the incision and the mitral annulus. Multiple 0 braided polyester horizontal mattress sutures with pledgets were placed along the exclusion line on the viable LV myocardium (**Fig. 3C**). As for the SAVE procedure, a collagen-impregnated Dacron knitted fabric was trimmed to create an elliptical shape and placed over the exclusion with a 1-cm allowance for LV closure. The last two sutures on the apex side were tied after deaeration of the LV (**Fig. 4D**). Finally, the LV was closed in a similar manner as in the SAVE procedure, and the bilateral papillary muscles were approximated during the PRP procedure (**Fig. 4E**). The line was secured by double 2-0 polypropylene over-and-over sutures from both ends

muscle.

both ends (**Fig. 3F**).

(**Fig. 4F**).

operations in this series32).

c. Posterior restoration procedure (PRP)

muscles were preserved in this operation.

(D) (E) (F)

Fig. **3A**. The schema shows the heart with ICM including a large antero-septal akinetic region. **3B.** The antero-lateral LV wall is opened along the left descending artery from the apex toward the base. **3C.** Multiple 0 braided polyester horizontal mattress sutures with pledgets are placed along the exclusion line of the septum, in a direction that proceeds from the apex to a septal site 1-2 cm below the aortic valve. **3D.** A collagen-impregnated Dacron knitted fabric (approximate 3×4 cm) is placed over the plicated defect of the myocardium and fixed with 2-0 polypropylene running suture. The last two sutures on the apex side are tied after deaeration of the LV. **3E.** Two felt strips are placed along the ventriculotomy on each side, and the excluded external scar is folded to reinforce the suture line with 2-0 polypropylene horizontal mattress sutures anchoring the allowance of Dacron fabric. **3F.** The suture line is secured by double 2-0 polypropylene over-and-over sutures from both ends.

Surgical Ventricular Restoration for Ischemic Cardiomyopathy with Functional Mitral Regurgitation 91

**3.3 Anatomical relationships between the mitral leaflet and the subvalvular apparatus** 

The mitral valve consists of the anterior and posterior leaflets, annulus, and chordae, supported by two papillary muscles to regulate forward blood flow from the left atrium to the LV. Under normal conditions, both mitral leaflets create a deep coaptation zone at endsystole to prevent regurgitant blood flow. However, earlier experimental and clinical studies demonstrated that restricted diastolic opening of the mitral leaflets increased valve tethering, resulting in functional MR in hearts with LV dysfunction33,34). The mechanism of functional MR can be understood in terms of an altered force balance on the mitral leaflets in systole; i.e., a combination of increased tethering forces that restrain the leaflets from closing and result from an altered three-dimensional geometry of leaflet attachments associated with LV dilatation and decreased ventricular forces that act to close the mitral leaflets. As a consequence of geometric remodeling, laterally displaced papillary muscles were detected in dilated LVs with ICM35). Although annular dilation is also one of the primary causes of functional MR, understanding of the geometric imbalance between the LV dimensions and the subvalvular apparatus is important to repair functional MR in patients

Earlier reports demonstrated that functional MR may result from dilation of the mitral annulus, laterally displaced papillary muscles, and enhanced tethering force of the valve leaflets in the hearts with dilated LV33,35-37). For these patients, functional MR was relieved by mitral valve plasty (MVP) including mitral annuloplasty (MAP) with an undersized flexible annuloplasty ring38), chordal cutting of the basal chordae39,40), papillary muscle approximation41-44), and chordal translocation45). We usually repair functional MR using MAP with a semi-rigid ring, and/or chordal cutting, and/or papillary muscle approximation. Chordal cutting and papillary muscle approximation were indicated for patients with a severely dilated LV caused by broad myocardial infarction, who would be

To perform MAP, the mitral valve was observed via the right-sided left atriotomy. When the MAZE procedure was required, radiofrequency ablation was performed prior to mitral valve surgery following Cox and associates46). The Cosgrove Valve Retractor System (Kapp Surgical Instrument, Inc. Cleveland, OH, USA) was used to obtain a wide surgical field around the mitral valve. First, 2-0 polyfilament braided vertical mattress sutures (Matsudaika Kogyo, Tokyo, Japan) were placed on the mitral annulus. The coaptation zone of the mitral valve was directly inspected by the water test to identify the valvular morphology. Basically, the etiology of functional MR with ICM involved tethering of the subvalvular apparatus caused by a dilated LV and annular dilatation. After identification of no organic changes of the mitral leaflet, a mitral annuloplasty ring was seated on the mitral annulus (**Fig. 5A**). An undersized semi-rigid ring (Carpenter-Edwards Physio Ring®; Edwards Life Science Corporation, Irvine, CA, USA) was used for patients with central MR, while a justsized asymmetric rigid ring (Carpentier-McCarthy-Adams IMR ETlogix annuloplasty ring®; Edwards Life Science Corporation) was used for patients with asymmetric MR from the

repaired by the SAVE procedure. Details of our techniques are described below.

**3.4 Mitral valve surgery for functional MR in patients with ICM** 

**3.5 Technical details of our mitral valve surgery** 

**for ICM** 

with ICM36).

Fig. **4A**. The schema shows the heart with ICM including a posterior akinetic region. **4B.** The akinetic region is opened 1 cm proximal from the apex on the posterior wall between bilateral papillary muscles. The incision is extended toward the base of the heart, reaching 1 cm below the mitral annulus. **4C.** Multiple 0 braided polyester horizontal mattress sutures with pledgets are placed along the exclusion line of the septum, with a direction that proceeds from the apex to a septal site 1-2 cm below the aortic valve. **4D.** A collagenimpregnated Dacron knitted fabric is trimmed to create an elliptical shape and is placed over the exclusion with a 1-cm allowance for closure of the LV. The last two sutures on the apex side are tied after deaeration of the LV. **4E.** Two felt strips are placed along the ventriculotomy on each side, and the excluded external scar is folded to reinforce the suture line with 2-0 polypropylene horizontal mattress sutures anchoring the allowance of Dacron fabric. The bilateral papillary muscles are approximated during the PRP procedure. **4F.** The suture line is secured by double 2-0 polypropylene over-and-over sutures from both ends.

#### **3.3 Anatomical relationships between the mitral leaflet and the subvalvular apparatus for ICM**

The mitral valve consists of the anterior and posterior leaflets, annulus, and chordae, supported by two papillary muscles to regulate forward blood flow from the left atrium to the LV. Under normal conditions, both mitral leaflets create a deep coaptation zone at endsystole to prevent regurgitant blood flow. However, earlier experimental and clinical studies demonstrated that restricted diastolic opening of the mitral leaflets increased valve tethering, resulting in functional MR in hearts with LV dysfunction33,34). The mechanism of functional MR can be understood in terms of an altered force balance on the mitral leaflets in systole; i.e., a combination of increased tethering forces that restrain the leaflets from closing and result from an altered three-dimensional geometry of leaflet attachments associated with LV dilatation and decreased ventricular forces that act to close the mitral leaflets. As a consequence of geometric remodeling, laterally displaced papillary muscles were detected in dilated LVs with ICM35). Although annular dilation is also one of the primary causes of functional MR, understanding of the geometric imbalance between the LV dimensions and the subvalvular apparatus is important to repair functional MR in patients with ICM36).

#### **3.4 Mitral valve surgery for functional MR in patients with ICM**

Earlier reports demonstrated that functional MR may result from dilation of the mitral annulus, laterally displaced papillary muscles, and enhanced tethering force of the valve leaflets in the hearts with dilated LV33,35-37). For these patients, functional MR was relieved by mitral valve plasty (MVP) including mitral annuloplasty (MAP) with an undersized flexible annuloplasty ring38), chordal cutting of the basal chordae39,40), papillary muscle approximation41-44), and chordal translocation45). We usually repair functional MR using MAP with a semi-rigid ring, and/or chordal cutting, and/or papillary muscle approximation. Chordal cutting and papillary muscle approximation were indicated for patients with a severely dilated LV caused by broad myocardial infarction, who would be repaired by the SAVE procedure. Details of our techniques are described below.

#### **3.5 Technical details of our mitral valve surgery**

90 Front Lines of Thoracic Surgery

(A) (B) (C)

(D) (E) (F)

Fig. **4A**. The schema shows the heart with ICM including a posterior akinetic region. **4B.** The akinetic region is opened 1 cm proximal from the apex on the posterior wall between bilateral papillary muscles. The incision is extended toward the base of the heart, reaching 1 cm below the mitral annulus. **4C.** Multiple 0 braided polyester horizontal mattress sutures with pledgets are placed along the exclusion line of the septum, with a direction that proceeds from the apex to a septal site 1-2 cm below the aortic valve. **4D.** A collagenimpregnated Dacron knitted fabric is trimmed to create an elliptical shape and is placed over the exclusion with a 1-cm allowance for closure of the LV. The last two sutures on the apex side are tied after deaeration of the LV. **4E.** Two felt strips are placed along the

ventriculotomy on each side, and the excluded external scar is folded to reinforce the suture line with 2-0 polypropylene horizontal mattress sutures anchoring the allowance of Dacron fabric. The bilateral papillary muscles are approximated during the PRP procedure. **4F.** The suture line is secured by double 2-0 polypropylene over-and-over sutures from both ends.

To perform MAP, the mitral valve was observed via the right-sided left atriotomy. When the MAZE procedure was required, radiofrequency ablation was performed prior to mitral valve surgery following Cox and associates46). The Cosgrove Valve Retractor System (Kapp Surgical Instrument, Inc. Cleveland, OH, USA) was used to obtain a wide surgical field around the mitral valve. First, 2-0 polyfilament braided vertical mattress sutures (Matsudaika Kogyo, Tokyo, Japan) were placed on the mitral annulus. The coaptation zone of the mitral valve was directly inspected by the water test to identify the valvular morphology. Basically, the etiology of functional MR with ICM involved tethering of the subvalvular apparatus caused by a dilated LV and annular dilatation. After identification of no organic changes of the mitral leaflet, a mitral annuloplasty ring was seated on the mitral annulus (**Fig. 5A**). An undersized semi-rigid ring (Carpenter-Edwards Physio Ring®; Edwards Life Science Corporation, Irvine, CA, USA) was used for patients with central MR, while a justsized asymmetric rigid ring (Carpentier-McCarthy-Adams IMR ETlogix annuloplasty ring®; Edwards Life Science Corporation) was used for patients with asymmetric MR from the

Surgical Ventricular Restoration for Ischemic Cardiomyopathy with Functional Mitral Regurgitation 93

(C)

(D)

(E) Fig. **5C**. Before suturing for PRP, two 0 braided polyester horizontal mattress sutures with pledgets are placed to plicate the posterior LV wall between bilateral papillary muscles. **5D.** Two sutures are tied to approximate bilateral papillary muscles. **5E.** MVR is performed via the ventriculotomy during SVR in a beating heart. The mitral leaflets are preserved as much as possible to prevent LV rupture, and 2-0 polyfilament braided vertical mattress sutures are placed on the mitral annulus from the LA toward the LV. These sutures are then anchored

to the mitral leaflets.

postero-median commissure. Chordal cutting was usually performed via the ventriculotomy during SVR, and thus the LA was closed with double 4-0 polypropylene over-and-over sutures.

For patients with a severely dilated LV requiring SAVE, chordal cutting was performed via the ventriculotomy during SVR. The basal chordae of the anterior and posterior mitral leaflets were completely cut with a pair of long scissors (**Fig. 5B**). Before suturing for SVR, two 0 braided polyester horizontal mattress sutures with pledgets (Ticron®; Tyco, Waltham, MA, USA) were placed to plicate the posterior LV wall between bilateral papillary muscles (**Fig. 5C**). They were then tied to approximate bilateral papillary muscles (**Fig. 5D**). SVR followed mitral valve surgery.

(A)

(B)

Fig. **5A**. The mitral valve is observed via the right-sided left atriotomy. After identification of no organic changes of the mitral leaflet, a mitral annuloplasty ring is seated on the mitral annulus. **5B.** For patients with a severely dilated LV requiring the SAVE procedure, the basal chordae of the anterior and posterior mitral leaflets are completely cut with a pair of long scissors via the ventriculotomy.

postero-median commissure. Chordal cutting was usually performed via the ventriculotomy during SVR, and thus the LA was closed with double 4-0 polypropylene

For patients with a severely dilated LV requiring SAVE, chordal cutting was performed via the ventriculotomy during SVR. The basal chordae of the anterior and posterior mitral leaflets were completely cut with a pair of long scissors (**Fig. 5B**). Before suturing for SVR, two 0 braided polyester horizontal mattress sutures with pledgets (Ticron®; Tyco, Waltham, MA, USA) were placed to plicate the posterior LV wall between bilateral papillary muscles (**Fig. 5C**). They were then tied to approximate bilateral papillary muscles (**Fig. 5D**). SVR

(A)

(B) Fig. **5A**. The mitral valve is observed via the right-sided left atriotomy. After identification of no organic changes of the mitral leaflet, a mitral annuloplasty ring is seated on the mitral annulus. **5B.** For patients with a severely dilated LV requiring the SAVE procedure, the basal chordae of the anterior and posterior mitral leaflets are completely cut with a pair of

over-and-over sutures.

followed mitral valve surgery.

long scissors via the ventriculotomy.

(C)

(D)

Fig. **5C**. Before suturing for PRP, two 0 braided polyester horizontal mattress sutures with pledgets are placed to plicate the posterior LV wall between bilateral papillary muscles. **5D.** Two sutures are tied to approximate bilateral papillary muscles. **5E.** MVR is performed via the ventriculotomy during SVR in a beating heart. The mitral leaflets are preserved as much as possible to prevent LV rupture, and 2-0 polyfilament braided vertical mattress sutures are placed on the mitral annulus from the LA toward the LV. These sutures are then anchored to the mitral leaflets.

Surgical Ventricular Restoration for Ischemic Cardiomyopathy with Functional Mitral Regurgitation 95

For patients with LV dyssynchrony or the inevitable cases with transection of a previously implanted LV lead during SVR, an epicardial permanent LV lead was placed on the lateral wall for cardiac resynchronization therapy (CRT) or CRT defibrillator (CRT-D)47). For the extremely severe cases with out-of-date generators for CRT or CRT-D, a new generator was

The results are expressed as means±SEM. An analysis was performed using the paired or unpaired Student's *t-*test to compare between before and after SVR, respectively. The

In 88 patients with ICM and MR, SVR was performed with three different procedures: EVCPP in 25 patients (28%), SAVE in 50 patients (57%) and PRP in 13 patients (15%). Two cases with antero-septal scars repaired by an overlapping cardiac volume reduction operation had a SAVE procedure. Mitral valve surgery was performed with MAP in 78 patients (89%) and MVR in 10 patients (11%). Of a total of 78 patients repaired with MAP, an under-sized Carpentier-Edwards Physio Ring was used in 72 patients (92%), and a just-sized Carpentier-McCarthy-Adams IMR ETlogix annuloplasty ring was used in 6 patients (8%). Of a total of 46 cases repaired with SAVE plus MAP, chordal cutting was required in 10 patients (22%), and papillary muscle approximation was required in 16 patients (35%). In the early period of this series, 10 patients were treated by MVR with the Carpentier-Edwards pericardial bioprosthesis (Edwards Life Science Corporation). Detailed

criterion for statistical significance was set at a value of *P*<0.05.

combinations of SVR and mitral valve surgery are summarized in **Table 1**.

Table 1. Surgical Ventricular Restoration and Mitral Valve Surgery.

Of the 88 patients with ICM and functional MR, concomitant procedures included CABG in 63 (72%), tricuspid valve surgery in 30 (34%), aortic valve surgery in 4 (5%), and the MAZE procedure in 7 (8%). The number of grafts for patients requiring CABG was 2.0±1.4/patient.

d. Supplemental procedures

upgraded during the operation.

**3.7 Statistical analysis** 

1. Operative procedures

**4. Results** 

For patients requiring PRP, the bilateral papillary muscles were surgically approximated during closure of the posterior wall of the LV. Thus, the posterior wall was approximated during the usual PRP procedure.

Although MVP is a standard operation for ICM with functional MR, mitral valve replacement (MVR) is indicated for a few limited cases. In the early period of this series, MVR via the ventriculotomy was performed to reduce aortic crossclamping time. Patients with ICM and MR caused by organic valvular changes were also treated by MVR, although they were excluded in this series.

MVR was performed via the ventriculotomy during SVR in a beating heart. The ascending aorta was declamped after closure of the LV, and the LV was opened in the akinetic region. The mitral leaflets were preserved as much as possible to prevent LV rupture, and 2-0 polyfilament braided vertical mattress sutures were placed on the mitral annulus from the LA toward the LV. These sutures were then anchored to the mitral leaflets. A prosthetic mitral valve was seated in the infravalvular position (**Fig. 5E**).

#### **3.6 Overview of the operative procedure**

#### a. Preparation for SVR and mitral valve surgery

Under general cardiac anesthesia and monitoring, the chest was entered via median sternotomy. CPB was installed via the ascending aorta with bicaval drainage under generalized heparinization. For patients requiring coronary artery bypass grafting (CABG), all anastomoses were completed prior to opening the LA. An LA vent tube was introduced via the right upper pulmonary vein (PV) to obtain a bloodless surgical field. When the MAZE procedure was required, left PV isolation was performed with a radiofrequency ablation system (AtriCure, Inc, West Chester, OH, USA). Under mild hypothermia, the ascending aorta was crossclamped. Antegrade tepid blood cardioplegia was delivered to obtain cardioplegic cardiac arrest. For maintenance, retrograde tepid blood cardioplegia was infused every 20 to 30 minutes.

b. MAP via the right-sided left atriotomy

MAP was performed via the right-sided left atriotomy. Details of the technique were described above. The LA was closed in two layers.

Aortic valve replacement was performed via the aortotomy prior to SVR, when it was required. Tricuspid valve surgery was also performed via the right atriotomy when it was necessary.

c. SVR and other mitral procedures via the ventriculotomy

After completion of MAP, the akinetic scar was opened to perform SVR and other mitral procedures via the LV. Selection of SVR depended on the location of the scar: the anterosepto-apical region for EVCCP, a broad antero-septal region for SAVE, and the posterior region for PRP. First, chordal cutting of both mitral leaflets was performed when it was indicated for patients requiring SAVE. Details of the technique were described above.

Secondly, papillary muscle approximation was performed for patients with a severely dilated LV requiring SAVE. The technical details were described above. For patients requiring PRP, the incision of the posterior wall was placed just between both papillary muscles, resulting in papillary muscle approximation by usual LV closure.

Finally, SVR was performed after completion of other mitral procedures. The details of the procedure were described above.

#### d. Supplemental procedures

For patients with LV dyssynchrony or the inevitable cases with transection of a previously implanted LV lead during SVR, an epicardial permanent LV lead was placed on the lateral wall for cardiac resynchronization therapy (CRT) or CRT defibrillator (CRT-D)47). For the extremely severe cases with out-of-date generators for CRT or CRT-D, a new generator was upgraded during the operation.
