**6.2 Arrhythmia surgery**

Patients with HCM are at increased risk of development of atrial fibrillation due to long-standing elevation of the left ventricular end-diastolic and left atrial pressures with subsequent left atrial chamber enlargement. Anyway, there is little evidence to support the addition of the Cox-maze procedure to septal myectomy.

**115**

**9. Conclusions**

*Surgical Treatment of Hypertrophic Obstructive Cardiomyopathy*

**6.3 Management of papillary muscle abnormalities**

**6.4 Management of concomitant MV disease**

potential development of SAM postoperatively.

**7. Other indications for septal myectomy**

**8. Septal myectomy versus alcohol septal ablation**

Sometimes, LVOT obstruction is present after septal myectomy because of anomalies of the (MV) valve apparatus: an accessory papillary muscle that arises from the ventricular septum and that is attached to the side of the anterior leaflet, may be present. In these patients, the accessory muscle has to be excised in its entirety. Other anomalies of the mitral apparatus may be the presence of accessory papillary muscles, or fusion of the anterior papillary muscle with the ventricular septum or left-ventricular free wall, or the presence of abnormal chordae tendineae that attach to the ventricular septum or to the free wall; all of this abnormalities may contribute to a persistent LVOT

In HCM, the anterior and inward displacement of papillary muscles is thought to

Degenerative MV disease requires attention at the time of myectomy in contrast

In our experience, when a concomitant mitral valve repair (MVR) is needed, we use a flexible posterior band that is slightly upsized, in order to minimize or avoid

Apical and midventricular variants of HCM are difficult entities to diagnose and treat medically, with the only alternative to myectomy being heart transplantation.

Despite an extended surgical septal myectomy is considered the gold standard

for managing symptomatic patients [1], percutaneous alcohol ablation of the septum has emerged as an alternative to surgical septal myectomy [30]. In this approach, alcohol is injected into the first septal perforator in order to create a localized myocardial infarction. The advantages of this non surgical procedures are a faster recovery with a subsequent quick return to daily lifestyle; anyway, the literature tends to support better long-term symptom relief in those patients who undergo septal myectomy [31] with a higher procedural success and a lower rate of complications when myectomy is performed in experienced centers compared with alcohol septal ablation. In addition, we have to keep in mind that young patients and patients with severe or relatively thin septal thickness and a very high LVOT gradient are considered poor candidates for the percutaneous approach. Importantly, surgical septal myectomy also facilitates the correction of other abnormalities of the LVOT and repair of associated abnormalities of the MV and anomalous papillary muscles that can also contribute to residual dynamic outflow tract obstruction.

Due to the complex ventricular phenotype of septal hypertrophy which increases the drag forces acting on the MV, and also due to primary MV anomalies, a multifaceted approach to repair and abolition of LVOT obstruction is required

create diastolic downwards vortex forces which pull the MV into the LVOT [29].

to SAM-mediated MR that typically resolves with extended myectomy alone.

gradient and should be corrected in order to perform an adequate SRT.

*DOI: http://dx.doi.org/10.5772/intechopen.86816*

*Cardiac Surgery Procedures*

**Figure 7.** *Loop technique.*

○ elliptical excision of the anterior mitral leaflet (excision site is then closed

○ elliptical excision with repositioning of major basal chords [24];

○ removal of accessory chordae that may tether the AML to the septum,

• *Annuloplasty ring sizes*: any reduction in annular circumference reduces the mitral—aortic angle, which increases the risk of SAM, so an annular undersizing should not be performed, in order to maintain the coaptation plane as

○ annular enlargement (post-MV repair, especially in Barlow's disease):

○ annular plication: plication sutures are used to tie down the PML to the

• "*Resection-plication-release*": in HCM, the concomitant use of myectomy, plication of the AML and release of the papillary muscles remodels the LV in order

• *Mitral valve replacement*: if SAM is severe and persistent despite exhaustive medical and surgical attempts at eliminating SAM, MV replacement can be the only option. In this setting, care must be taken to properly resect any remain-

Patients with HCM are at increased risk of development of atrial fibrillation due to long-standing elevation of the left ventricular end-diastolic and left atrial pressures with subsequent left atrial chamber enlargement. Anyway, there is little evidence to support the addition of the Cox-maze procedure to septal

36–40 mm annular rings are used in presence of excessive mitral tissue [26];

with double-layer prolene stitches) [23];

much as possible away from the septum:

ing mitral tissue, to prevent SAM recurring.

resulting in SAM [25].

annulus [27];

to reduce SAM [28].

**6.2 Arrhythmia surgery**

**114**

myectomy.

## **6.3 Management of papillary muscle abnormalities**

Sometimes, LVOT obstruction is present after septal myectomy because of anomalies of the (MV) valve apparatus: an accessory papillary muscle that arises from the ventricular septum and that is attached to the side of the anterior leaflet, may be present. In these patients, the accessory muscle has to be excised in its entirety. Other anomalies of the mitral apparatus may be the presence of accessory papillary muscles, or fusion of the anterior papillary muscle with the ventricular septum or left-ventricular free wall, or the presence of abnormal chordae tendineae that attach to the ventricular septum or to the free wall; all of this abnormalities may contribute to a persistent LVOT gradient and should be corrected in order to perform an adequate SRT.

In HCM, the anterior and inward displacement of papillary muscles is thought to create diastolic downwards vortex forces which pull the MV into the LVOT [29].

### **6.4 Management of concomitant MV disease**

Degenerative MV disease requires attention at the time of myectomy in contrast to SAM-mediated MR that typically resolves with extended myectomy alone.

In our experience, when a concomitant mitral valve repair (MVR) is needed, we use a flexible posterior band that is slightly upsized, in order to minimize or avoid potential development of SAM postoperatively.

## **7. Other indications for septal myectomy**

Apical and midventricular variants of HCM are difficult entities to diagnose and treat medically, with the only alternative to myectomy being heart transplantation.

### **8. Septal myectomy versus alcohol septal ablation**

Despite an extended surgical septal myectomy is considered the gold standard for managing symptomatic patients [1], percutaneous alcohol ablation of the septum has emerged as an alternative to surgical septal myectomy [30]. In this approach, alcohol is injected into the first septal perforator in order to create a localized myocardial infarction. The advantages of this non surgical procedures are a faster recovery with a subsequent quick return to daily lifestyle; anyway, the literature tends to support better long-term symptom relief in those patients who undergo septal myectomy [31] with a higher procedural success and a lower rate of complications when myectomy is performed in experienced centers compared with alcohol septal ablation. In addition, we have to keep in mind that young patients and patients with severe or relatively thin septal thickness and a very high LVOT gradient are considered poor candidates for the percutaneous approach. Importantly, surgical septal myectomy also facilitates the correction of other abnormalities of the LVOT and repair of associated abnormalities of the MV and anomalous papillary muscles that can also contribute to residual dynamic outflow tract obstruction.

#### **9. Conclusions**

Due to the complex ventricular phenotype of septal hypertrophy which increases the drag forces acting on the MV, and also due to primary MV anomalies, a multifaceted approach to repair and abolition of LVOT obstruction is required

in HOCM. Septal myectomy is fundamental and represent the first step to any of these. In addition, specific techniques for SAM in the context of HOCM have been described. Each technique proposed for the surgical correction of HOCM has evolved to meet a specific anatomical problem, so it is inappropriate to rate one surgical procedure as superior to another; anyway, repair which resects as little tissue as possible and that does not distort the anatomy significantly should be preferred. Surgeons must understand the anatomical cause of LVOT obstruction, and this should guide them to the choice of the technique to adopt. Ease of repair should be also considered, as this will have beneficial consequences for the total time under cardiopulmonary bypass.

Alcohol septal ablation for HCM has been proposed as a less-invasive alternative to surgical myectomy, although its role in the management of HCM associated with SAM requires further investigations so that, the current evidence, supports the use of septal myectomy in the clinical practice [32].
