Interact CardioVasc Thorac Surg 2005;4:475-477. doi:10.1510/icvts.2005.109868
© 2005 European Association of Cardio-Thoracic Surgery
Work in progress report - Cardiac general |
Restoring papillary muscle dimensions during restoration in dilated hearts
Gerald Buckberga,*,
Lorenzo Menicantib,
Sergio De Oliveirac,
Tadashi Isomurad and the RESTORE team
a David Geffen School of Medicine at UCLA, 10833 Le Conte Avenue, 62-258 CHS, Los Angeles, CA 90095-1741, USA
b San Donato Hospital, Via Morandi 30, Milan, Italy
c University of Sao Paulo Medical School, Sao Paulo, Brazil
d Hayama Heart Center, Kanagawa, Japan
Received 27 May 2005;
received in revised form 29 June 2005;
accepted 30 June 2005
*Corresponding author. Tel.: +1-310-206-1027; fax: +1-310-825-5895.
E-mail address: gbuckberg{at}mednet.ucla.edu (G. Buckberg).
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Abstract
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Left ventricular papillary muscle geometry is distorted in dilated non-ischemic hearts, and following anterior infarction caused by a wrap around left anterior descending artery occlusion. Loss of the apex creates a spherical left ventricular (LV) chamber, and subsequent dilation causes secondary mitral insufficiency by stretching the annulus, altering tethering of the chords and widening the dimension between the bases of papillary muscles to impair leaflet coaptation. This report will describe an intraventricular way to narrow the widened inter papillary muscle distance toward normal.
Key Words: Dilated heart; Wrap around anterior infarction; Mitral insufficiency; Papillary muscle imbrication; SVR; Ventricular restoration
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1. Introduction
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The geometric goal in restoration is to rebuild a conical left ventricular chamber, and sometimes simultaneously deal with the secondary ventricular changes that produce mitral insufficiency in non-ischemic and ischemic disease. Factors causing mitral insufficiency after cardiac dilation include widening the mitral annulus, ventricular stretching to impair mitral leaflet coaptation by tethering, and widened dimension between the bases of papillary muscle heads to further diminish leaflet coaptation [1]. These stretched papillary muscle dimensions may follow wrap around left anterior artery myocardial infarction, since the left ventricular apex is lost and substantial remote muscle dilation is needed for compensation.
Recent studies describe why functional mitral insufficiency is worsened by widening the dimension between papillary muscle heads [1], and how narrowing this distance improves mitral valve function. Such widening distance between papillary muscle bases occurs with global dilation, or secondarily when the apical tip is lost following wrap around left anterior descending infarction, as shown in Fig. 1 a–c. Simultaneously, the papillary muscle bases move toward a more posterior and cephalad position so that bringing these together with imbrication with the Fontan suture during restoration in ischemic disease might create a patch position that confronts the mitral valve plane and distorts chamber geometry [2].
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Fig. 1. (a) Left ventricular globular shape after wrap around anterior infarction with asynergic (non-functional area) involving the apical part of inferior wall. (b) Cross sectional view of the normal heart (left) and dilated heart (right), showing (1) widening of the mitral annulus, (2) tethering of chords with apical displacement of potential coaptation leaflet point, and (3) widening of dimensional distance between bases of papillary muscles.
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This report describes an intraventricular technique employed by several members of the RESTORE group that narrows the secondary widening between bases of papillary muscle heads during ventricular restoration of ischemic or non-ischemic dilated cardiomyopathy with secondary mitral regurgitation.
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2. Methods
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Twenty patients with secondary mitral insufficiency in non-ischemic (n=11) or ischemic (n=9) dilated cardiomyopathy underwent surgical ventricular restoration. Preoperative extent of mitral insufficiency by echocardiography was >2.5 gradation, and trans gastric echocardiography showed the mitral annulus was >35 mm. The dimensional distance between the papillary muscle base heads increased from <2.4 cm baseline levels, normal by Hvass [3] to >3.5 cm.
Stretching of the width between papillary muscle bases did not involve scar, but was secondary to compensatory remote muscle dilation that followed dilation after global cardiomyopathy or large wrap around anterior infarction.
All patients underwent patch placement to rebuild ventricular volume, mitral annuloplasty and narrowing of the widened distance between papillary muscle heads.
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3. Results
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These technical considerations were used to narrow the widened dimension. Fig. 2a displays the open chamber, where the anterior incision is made approximately 2–3 cm from the LAD vessel, and is not extended beyond the apex. The same incision was made in ischemic and non-ischemic venrtricles. No scarring was observed in the remote muscle where the interpapillary muscle distance was stretched. LV restoration was done in ischemic hearts, and pacopexy or Surgical Anterior Ventricular Exclusion (SAVE) was done in non-ischemic hearts. The widening between papillary muscle heads is evident, and Fig. 2b shows how two mattress sutures with pledgets are placed between (a) the base of the anterior lateral, (b) the widened or stretched ventricular wall, and (c) the posterior medial papillary muscles. This suture is always placed onto a wedge of wall tissue between the papillary muscle heads. When secured, as shown in Fig. 2c and in Video 1 (as shown in the insert video), the widened distance between muscle heads is restored to the more normal dimension, averaging  1.5 cm between papillary muscle heads.
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Fig. 2. (a) Intraventricular view of widening between papillary muscle bases and scarring of apical part of inferior wall, (b) mattress sutures placed into bases of papillary muscle heads and intervening ventricular tissue, (c) securing the mattress sutures and ventricular muscle narrow this distance and restore more normal geometry.
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Video 1. Sequence of opening the anterior left ventricular wall, exposure, and placing mattress sutures from base of the papillary muscle, then into a wedge of ventricular wall, and then in the base of other papillary muscle.
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Postoperative trans esophageal echo cardiography documented correction of mitral insufficiency in all patients, with a final gradation score of 0.2±0.1, and confirmed the narrowing of the widened distance between papillary muscle heads. The papillary muscle technique was used in 21 patients without complications. Fig. 3 shows pre- and postoperative echocardiographic appearance of papillary muscle distances, and Table 1 shows ejection fraction, end systolic and diastolic volume indices and left ventricular and pulmonary pressures before and after operation.
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Fig. 3. Trans gastric echocardiogram showing the preoperative widened distance between papillary muscle heads (left) and postoperative narrowed dimension on right image.
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4. Discussion
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This procedure for papillary muscle restoration of the dilated heart patients with mitral insufficiency defines how three-dimensional knowledge of the ventricular chamber dimensions improves ventricular rebuilding of size and shape toward normal. Papillary muscle interventions are only done when the trans gastric echocardiogram shows this inter papillary head distance is increased. A recent report by Yu has established a solid MRI based background for why widening this distance between papillary muscle heads causes functional mitral regurgitation [4]. Similar widening was described by Nair [5] and Hvass [3] who advised alternate pathways to narrow this widened dimension in patients with ischemic mitral insufficiency. Conversely, Matsui has made a similar papillary muscle base repair in non-ischemic disease, which started around the time our method was orally described [6].
Stretching of remote muscle tissue without infarction caused this cavity dilation change in these patients. Consequently, this structural abnormality is not related to having a specific disease process cause widening of the inter-papillary muscle dimension.
The correct distance between papillary muscle heads is unknown, but widening from 2.5±0.3 to 3.8±0.6 cm was described by Hvass. Intra-operative evaluation is possible by analysis of trans gastric short axis echocardiogram, coupled with the understanding why dealing with this component of functional mitral regurgitation deals with the papillary muscle component of this process.
We recommend routinely accessing dimensions between papillary muscle heads by transgastric echocardiogram. The described intraventricular procedure to narrow the widened distance between bases of papillary muscles supplements the mitral annular narrowing used during restoration in patients with non-ischemic or ischemic dilated cardiomyopathy.
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References
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- Liel-Cohen N, Guerrero JL, Otsuji Y, Handschumacher MD, Rudski LG, Hunziker PR, Tanabe H, Scherrer-Crosbie M, Sullivan S, Levine RA. Design of a new surgical approach for ventricular remodeling to relieve ischemic mitral regurgitation: insights from 3-dimensional echocardiography. Circulation 2000;101:2756–2763.[Abstract/Free Full Text]
- Menicanti L, Frigiola A, Buckberg GD, Santambrogio C, Ranucci M, Santo D. and RESTORE Group. Ischemic mitral regurgitation; intraventricular papillary muscle imbrication without mitral ring. J Thorac Cardiovasc Surg 2002;123:1041–1050.[Abstract/Free Full Text]
- Hvass U, Tapia M, Baron F, Pouzet B, Shafy A. Papillary muscle sling: a new functional approach to mitral repair in patients with ischemic left ventricular dysfunction and functional mitral regurgitation. Ann Thorac Surg 2003;75:809–811.[Abstract/Free Full Text]
- Yu HY, Su MY, Liao TY, Peng HH, Lin FY, Tseng WY. Functional mitral regurgitation in chronic ischemic coronary artery disease: analysis of geometric alterations of mitral apparatus with magnetic resonance imaging. J Thorac Cardiovasc Surg 2004;128:543–551.[Abstract/Free Full Text]
- Nair RU, Williams SG, Nwafor KU, Hall AS, Tan LB. Left ventricular volume reduction without ventriculectomy. Ann Thorac Surg 2001;71:2046–2049.[Abstract/Free Full Text]
- Matsui Y, Fukada Y, Naito Y, Sasaki S. Integrated overlapping ventriculoplasty combined with papillary muscle plication for severely dilated heart failure. J Thorac Cardiovasc Surg 2004;127:1221–1223.[Free Full Text]
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Abstract
1. Introduction