Pacopexy: Restoration Procedure for Nonischemic Dilated Cardiomyopathy

Pacopexy: Restoration Procedure for No fischelnic Dilated Cardiomyopathy Sergio A. 01iveira, Hisayoshi Suma, Gerald D. Buckberg, Constantine L. Athanasuleas, Friedhelm Beyersdorf, and the RESTORE Group

n heart failure, a common undcrl~'ing filctor is thc

I .modification of tile heart's shape from elliptical to sl)hcrical. This usually rcsuhs from stretched remote muscle after ischcmia, secondary dilatation after valve insuflicicncy, and intrinsic myocite defects fi'om nonischcmic cardiomyol)athy. The normal heart has a helical shal)e, with an elliptical filler orientation that proceeds toward the apex. Nornlal lil,er shortening is only 15%, l,ut this structurally ol,lique fiber conformation causes a 60% ejection fraction. In contrast, congestive heart failm'c patients undergo a structural change and develop a spherical shape through alfieal dilation. Tiffs causes a more transverse fiber orientation, so that 15% normal fiber shortening allows only 30% ejection fractiold," with fiwther reduction after intrinsically abnormal myocites. Current surgical aplwoaches to the spherical shape can suecessfidly restore tile elliptical formation in ischemie disease by tile surgical ventricular restoration with good results. 3-5 Recent intraoperative echoeardiographic tests in nonisehemic dilated cardiomyopathy have defined the weakest area by evaluating how regional left vcntricular segments arc ahered by disease. Tile consequence was site-selected treatments to exelude either tile lateral wall or the SCl~tunl.6"7 This approach was stimulated through evolving recognition of the basic fiber orientation pattern and how it is ahercd by dilation.

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Tile novel concepts and anatomic dissections of Francisco Torrcnt-Guasp ~;,9defined tile normal cardiac structure and were then used to explain vcntricular dynanfics in health and disease, lie anatolnically u n s c r o l l e d tile left ventricle to show that the cardiac configuration contains two loops: a transverse lmsal loop to embrace or buttress a helical apical loop that contains two reciprocal spiral components called descending and ascending segments. These oldiquely oriented fibers are responsible for twisting to eject, and for suction for venous r e t u r n , and this shape can be surgically restored. Tile u n d e r l y i n g geometric change in congestive h e a r t failure occurs when tile apical loop becomes spherical so that the n a t u r a l l y oblique fibers assume a m o r e t r a n s v e r s e orientation through dilation and then resemble the basal loop. Site selection becomes critical in idiopathic dilated c a r d i o m y o p a t h y when tile underlying disease is inhomogcneous. Restoration of the n o r m a l shallc of tile h e a r t can be achieved by excluding tile SClltum with an i n t r a e a r diac patch inserted between the papillary muscle and subaortic septum to r e s t o r e the conical shape. Anatomically, this p r o c e d u r e Septal A n t e r i o r Ventricular Exclusion, but we call it " P a c o p e x y " in recognition of tlle contributions of Francisco (Paco) T o r rent-Guasp.

Operative Tcclmiques it; Thoracic and Cardiovascular Surgery, Vol 7, No 2 (May), 2002: pp 7 6 - 8 3

PACOPEXY FOR NONISCIIEMICI)II.Vi'ED CARI)IOMYOI'ATIIY

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1 Access to the heart is achieved through a median sternotomy. Cardiolmhnonary bypass is established by ascending aortic cammlation. Ventricular restoration is usually performed in the beating heart. The left ventricle is decompressed via a cannula placed into its cavity through the right superior puhnonary vein. The left ventricle is opened front the apex toward the base, through an incision made about 2 to 3 cm lateral to the left anterior descending coronary artery. Clot is evacuated if present.

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2 The decision to preserve or t-eplace tile mitral valve depends on surgical judgement and is more common when left ventricular vohnne index is more than 120 mL/m 2. (A) If a prosthesis is imlilanted, we try to preserve as much of the native mitral vah-e and the subvalvular aplmratus as possible. To do this, we detach the anterior leaflet near the annulus, fohl it over, and suture it over the posterior annulus, thus preserving both papillary muscles and their chordae tendinea. (B) An undersized prosthesis is then implanted, with the intention of shrinking the base of the heart. (B) As an alternate technique to lireserve the tethering apparatus of the valve, we excise a triangle in the central part of the anterior leaflet, leaving in place all the chord and papillary muscles to preserve the elliptical shape.

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3 (A) When a preoperative decision is made to replace tile mitral valve, the procedure is usually performed through tile left ventriculotomy. This method avoids opening the left atrium or the interatrial sel)tum. For mitral valve repair, access is usually through the interatrial septum with the possibility of extending the incision to the roof of the left atrium. (B) A posterior annuloplasty is used for mitral repair. The tricuspid vah'e ring is usually repaired by a annuloplasty by using the imbrication technique described by DeVega. l~

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4 After treating the mitral vah'e liroblenl, the aortic clam 1) is removed so that ventricular restoration can l)e performed while the (lccomlircsscd heart is l)eating. A small vent is l)ositionc(l ill tile ascending aorta to remove any reninant of air. The ventricular cavity is inspected for any residual thronllms and to identify any cndoeardial scar. Palpation of the left ventricle is a very important maneuver to identify noncontracting areas of the myoeardium. Using the thuml) and the index finger, we can analyze the contraction of the septum and anterolateral wall. A transitional line is traced from the base of the anterior papillary muscle toward the septum to within 2 cm of the aortic valve as the site for septal suture placement. Interrupted intraventrieular mattress multifilament polyester sutures containing Teflon felt pledgers are attached to the septum approximately 1 cm apart. ~Xreuse the same approach for suture placement on the lateral wall, but the stitches are passed from the external sitrface to the internal one. An internal neck is made by the septtim and lateral wall that will lie covered by a patch.

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5 A stnall oval patch of Dacron (Ilaenmshiehl; Meadox Corp., Oakland, NJ) or pericardium 2 to 3 X ,1 cm in size is used to reduce tile ventrieular cavity and to restore tile elliptical shape of tile left ventricle. The previously placed sutures are transferred to the lmtch, leaving a rim of approxinmtely one cm around tile edges of the patch. The external rim of tile patch is securcd to the underlying muscle by a running suture to help in the hemostasis.

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6 Tlle left ventriculotomy is closed by direct suture with or without a pledget. A transesophageous echocardiogram is performed after ventricular closure to evaluate the anatomic and fimctional resuhs of the surgical procedure.

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7 An examl,le of tile l,reoperative sl,herieal shape of a dilated heart (left lmnel) and tile l,OStoperativc elliptical shape that can be attained after surgical restoration (right panel).

I*ACOPEXY FOR NONISCIIEMIC I)II,ATEI) CARillOMYOI'ATilY

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This technique is used for idiopathic dilated eardiomy,,pathy and resembles a nlethod used to restore the left ventricle size and shape in patients with anterior septal akinesia or ,lyskinesia a,t,ll in ischemie cardiomyopathy. Its aI,l,lieation in idiopathic dilated eardiomyopathy was a resuh of recognizing that ventricular muscle dysfimction may be inhomogeneous in this type of cardiomyopathy as well as in those patients who have previously had a discrete myocardial infarction.12 Consequently, this surgery can become usefid in lmtients with more severe disease in the septal region. Once the ventricle is completely decompressed, an echocardiogram can be used to document the different degrees of cardiomyolmthy in different regions of the heart. 6,7 REFERENCES 1. Ingels NB Jr: Myocardial fiber arehiteeture and h'ft ventrieular funclion. Teehnol lleahh Care 5:,15-52, 1997 2. Salin EA: Filler orientation and ejection fracti.n in the human ventricle. l~iophys J 9:951-961, 1969 3. D . r V, Salmtier M, D i D . n a t . 31, et al: Efficacy of endoventricttlar patch plasty in large p.st-infarction akinetic sear and severe LV dysfunction. Comparison with a series of large dyskne/ic sear. J Thorac Cardiovasc Surg 116:50-59, 1998 91. Jatene AD: Left ventricular aneurysmectomy. Resseclion or reconstruction. J Thorac Cardiovasc Surg 89:321-331, 1985 5. Athanasuleas CL, Slanley AWII Jr, Buekl.erg GD, el al: Surgical anterior ventrieular eml.eardial rest.rati.n (SAVER) in the dilated

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remodeled ventricle following anterior myocardial infilreti.n. J Amcr Coil Cardi.! 37:1199-1209, 2001 Suma 1I, Isomura T, llorii T, et al: Non-transplant cardiac surgery for end-stage cardiomyopathy. J Thorac Cardi.vase Surg 119:1233-12.t5, 2000 Is.mura T, Suma 1I, llorii T, et al: Partial left ventrieuleetomy. ventriculoplasty or valvular surgery fi~r idiopathic dilated cardiomiopalily. Tile role of intraoperative echoeardiography. Eur J Cardiothorac Surg 17:239-2.15, 2000 Torrent-Guasp F, Whimsler WF, Redmann K: A silicone ruhber mouhl of tile heart. Technol llealth Care 5:13-20, 1997 Torrent-Guasp F: Sobre morfologia y fimeionalismo cardiac.s. Rev Esp Cardiol 20:1, 1067 De~%ga NG: La anuloplaslia seletiva, regulable y lwrmanenle. Rev Esp Cardiol 25:555-557, 1972 Cooley DA, Frazier OII, Duncan JM, et al: lntracavitary repair of ventrieular aneurysm and regional dyskinesia. Ann Surg 215:.t17-123, 1992 Suma I1, Beyersdorf F, Buekberg G, et al: Unlmblished data. Presented to tile 8 h h Annual Meeting of the American Association for Thoracic Surgery, San Diego, CA, May 2001

From the I leart Institute (lnCor), University of Sao Paulo Medical School. Sao Paulo. Brazil; tile tlayama tleart Center, Kanaga~a, Japan; Univer,-,ity, f CalifiJrnia l,os Angeles School of Medicine, Los Angeles, CA; the Norwood Clinic and Kemp-Carraway lteart Institute, Birmingham, ALl and the Department of Cardiovascular Surgery, AllJert-Luth~igs-University, Freiburg, Germany. Address reprint requests to Gerahl D. Buckberg. MD, UCLA School of Medicine, Department of Surget)', B,x 9507,11, l,os Angeles, CA. Copyright 2002, Elsevier Science (USA). All rights reserved. 1522-2912/02/0702-0002535.00/0

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