An Experimental Rabbit Model for Off-Pump Left Ventricular Reconstruction Following Left Ventricular Aneurysm
Background. Cardiac electromechanical remodeling following left ventricular reconstruction (LVR) surgery is not fully understood. Further development of an animal model will facilitate investigations in this area. In the present study, we aimed to establish a novel LVR procedure without the use of cardiopulmonary bypass in a rabbit left ventricular (LV) aneurysm model.
Methods. LV aneurysm was created in 6 rabbits by ligation of the distal left coronary artery. More than a month later, LVR aneurysm surgery was performed off-pump using a purse-string suture around the aneurysm. Cardiac dimensions and function were evaluated using echocardiographic techniques perioperatively and 4 weeks after LVR surgery. Six structurally normal hearts were used as controls.
Results. LVR surgery was successfully performed in all 6 rabbits. Both LV end-diastolic volume (LVEDV, 4.6 ± 0.9 to 3.3 ± 0.6 mL; P < .01) and LV end-systolic volume (LVESV, 2.5 ± 0.6 to 1.5 ± 0.2 mL, P < .01) were decreased immediately postsurgery versus presurgery, and LV ejection fraction (LVEF) was increased (44.5 ± 5.3 to 55.6 ± 4.8%, P < .001). For comparison, in normal rabbits (n = 6), LVEDV, LVESV and LVEF were 3.1 ± 0.7 mL, 1.2 ± 0.5 mL, and 64.5 ± 8.8%, respectively. During follow-up, one rabbit died 3 weeks after surgery from an unknown cause. In the remaining 5 animals, improvements of LVEDV (3.7 ± 0.4 mL, P < .05), LVESV (1.7 ± 0.3 mL, P < .01), and LVEF (53.1 ± 2.8%, P < .01) were maintained versus presurgery values for more than 4 weeks after LVR.
Conclusions. Off-pump LVR of rabbit LV aneurysm is an effective and less invasive surgery that resulted in sustained improvement in cardiac function with no gross intraoperative or postoperative mortality. This may be a useful model for investigations of electromechanical remodeling following LVR.
Buckberg GD. 2004. Early and late results of left ventricular reconstruction in thin-walled chambers: is this our patient population? J Thorac Cardiovasc Surg 128:21-6.nDor V, Sabatier M, Di Donato M, et al. 1998. 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 116:50-9.nFurutachi A, Yoshikai M, Ohnishi H, et al. 2005. Left ventricular pseudo-false aneurysm after a myocardial infarction; application of heart positioner. Kyobu Geka 58:879-82.nHendzel P, Gryszko L, Szczawinski W, et al. 2005. Off-pump coronary artery bypass grafting and left ventricular aneurysm resection-a case report. Pol Merkuriusz Lek 19:188-90.nJatene AD. 1985. Left ventricular aneurysmectomy. Resection or reconstruction. J Thorac Cardiovasc Surg 89:321-31.nKanashiro RM, Nozawa E, Murad N, et al. 2002. Myocardial infarction scar plication in the rat: cardiac mechanics in an animal model for surgical procedures. Ann Thorac Surg 73:1507-13.nKesler KA, Fiore AC, Naunheim KS, et al. 1992. Anterior wall left ventricular aneurysm repair. A comparison of linear versus circular closure. J Thorac Cardiovasc Surg 103:841-7.nLee BH, Kim WH, Choi MJ, et al. 2002. Chronic heart failure model in rabbits based on the concept of the bifurcation/trifurcation coronary artery branching pattern. Artif Organs 26:360-5.nLi L, Nikolski V, Wallick DW, et al. 2005. Mechanisms of enhanced shock-induced arrhythmogenesis in the rabbit heart with healed myocardial infarction. Am J Physiol Heart Circ Physiol 289:H1054-68.nLundblad R, Abdelnoor M, Svennevig JL. 2003. Repair of left ventricular aneurysm: surgical risk and long-term survival. Ann Thorac Surg 76:719-25.nMarkovitz LJ, Savage EB, Ratcliffe MB, et al. 1989. Large animal model of left ventricular aneurysm. Ann Thorac Surg 48:838-45.nMatsubayashi K, Fedak PWM, Mickle DAG, et al. 2003. Improved left ventricular aneurysm repair with bioengineered vascular smooth muscle grafts. Circulation 108:II219-25.nPodesser B, Wollenek G, Seitelberger R, et al. 1997. Epicardial branches of the coronary arteries and their distribution in the rabbit heart: the rabbit heart as a model of regional ischemia. Anat Rec 247:521-7.nPopovic AD, Neskovic AN, Marinkovic J, et al. 1996. Acute and long-term effects of thrombolysis after anterior wall acute myocardial infarction with serial assessment of infarct expansion and late ventricular remodeling. Am J Cardiol 77:446-50.nRatcliffe MB, Wallace AW, Salahieh A, et al. 2000. Ventricular volume, chamber stiffness, and function after anteroapical aneurysm plication in the sheep. J Thorac Cardiovasc Surg 119:115-24.nSakaguchi G, Young RL, Komeda M, et al. 2001. Left ventricular aneurysm repair in rats: structural, functional, and molecular consequences. J Thorac Cardiovasc Surgery 121:750-61.nSakakibara Y, Tambara K, Lu F, et al. 2002. Combined procedure of surgical repair and cell transplantation for left ventricular aneurysm: an experimental study. Circulation 106:I193-7.nSavage EB, Downing SW, Ratcliffe MB, et al. 1992. Repair of left ventricular aneurysm. Changes in ventricular mechanics, hemodynamics, and oxygen consumption. J Thorac Cardiovasc Surg 104:752-62.nSchenk S, McCarthy PM, Starling RC, et al. 2004. Neurohormonal response to left ventricular reconstruction surgery in ischemic cardiomyopathy. J Thorac Cardiovasc Surg 128:38-43.nSchwarz ER, Speakman MT, Kloner RA. 2000. A new model of ventricular plication: a suturing technique to decrease left ventricular dimensions, improve contractility, and attenuate ventricular remodeling after myocardial infarction in the rat heart. J Cardiovasc Pharmacol Ther 5:41-9.nShapira OM, Davidoff R, Hilkert RJ, et al. 1997. Repair of left ventricular aneurysm: long-term results of linear repair versus endoaneurysmorrhaphy. Ann Thorac Surg 63:701-5.nWalker JC, Guccione JM, Jiang Y, et al. 2005. Helical myofiber orientation after myocardial infarction and left ventricular surgical restoration in sheep. J Thorac Cardiovasc Surg 129:382-90.nYu Y, Gu CX, Wei H, et al. 2005. Repair of left ventricular aneurysm during off-pump coronary artery bypass surgery. Chin Med J (Engl) 118:1072-5.nMaxwell MP, Hearse DJ, Yellon DM. 1987. Species variation in the coronary collateral circulation during regional myocardial ischaemia: a critical determinant of the rate of evolution and extent of myocardial infarction. Cardiovasc Res 21:737-46.nNishina T, Nishimura K, Yuasa S, et al. 2001. Initial effects of the left ventricular repair by plication may not last long in a rat ischemic cardiomyopathy model. Circulation 104:I241-5.n
How to Cite
Author Disclosure & Copyright Transfer Agreement
In order to publish the original work of another person(s), The Heart Surgery Forum® must receive an acknowledgment of the Author Agreement and Copyright Transfer Statement transferring to Forum Multimedia Publishing, L.L.C., a subsidiary of Carden Jennings Publishing Co., Ltd. the exclusive rights to print and distribute the author(s) work in all media forms. Failure to check Copyright Transfer agreement box below will delay publication of the manuscript.
A current form follows:
The author(s) hereby transfer(s), assign(s), or otherwise convey(s) all copyright ownership of the manuscript submitted to Forum Multimedia Publishing, LLC (Publisher). The copyright transfer covers the exclusive rights to reproduce and distribute the article and the material contained therein throughout the world in all languages and in all media of expression now known or later developed, including but not limited to reprints, photographic reproduction, microfilm, electronic data processing (including programming, storage, and transmission to other electronic data record(s), or any other reproductions of similar nature), and translations.
However, Publisher grants back to the author(s) the following:
- The right to make and distribute copies of all or part of this work for use of the author(s) in teaching;
- The right to use, after publication in The Heart Surgery Forum, all or part of the material from this work in a book by the author(s), or in a collection of work by the author(s);
- The royalty-free right to make copies of this work for internal distribution within the institution/company that employs the author(s) subject to the provisions below for a work-made-for-hire;
- The right to use figures and tables from this work, and up to 250 words of text, for any purpose;
- The right to make oral presentations of material from this work.
Publisher reserves the right to grant or refuse permission to third parties to republish all or part of the article or translations thereof. To republish, such third parties must obtain written permission from the Publisher. (This is in accordance with the Copyright Statute, United States Code, Title 17. Exception: If all authors were bona fide officers or employees of the U.S. Government at the time the paper was prepared, the work is a “work of the US Government” (prepared by an officer or employee of the US Government as part of official duties), and therefore is not subject to US copyright; such exception should be indicated on signature lines. If this work was prepared under US Government contract or grant, the US Government may reproduce, royalty-free, all or portions of this work and may authorize others to do so, for official US Government purposes only, if the US Government contract or grant so requires.
I have participated in the conception and design of this work and in the writing of the manuscript and take public responsibility for it. Neither this manuscript nor one with substantially similar content under my authorship has been published, has been submitted for publication elsewhere, or will be submitted for publication elsewhere while under consideration by The Heart Surgery Forum, except as described in an attachment. I have reviewed this manuscript (original version) and approve its submission. If I am listed above as corresponding author, I will provide all authors with information regarding this manuscript and will obtain their approval before submitting any revision. I attest to the validity, accuracy, and legitimacy of the content of the manuscript and understand that Publisher assumes no responsibility for the validity, accuracy, and legitimacy of its content. I warrant that this manuscript is original with me and that I have full power to make this Agreement. I warrant that it contains no matter that is libelous or otherwise unlawful or that invades individual privacy or infringes any copyright or other proprietary right. I agree to indemnify and hold Publisher harmless of and from any claim made against Publisher that relates to or arises out of the publication of the manuscript and agree that this indemnification shall include payment of all costs and expenses relating to the defense of any such claim, including all reasonable attorney’s fees.
I warrant that I have no financial interest in the drugs, devices, or procedures described in the manuscript (except as disclosed in the attached statement).
I state that the institutional Human Subjects Committee and/or the Ethics Committee approved the clinical protocol reported in this manuscript for the use of experimental techniques, drugs, or devices in human subjects and appropriate informed consent documents were utilized.
Furthermore, I state that any and all animals used for experimental purposes received humane care in USDA registered facilities in compliance with the “Principles of Laboratory Animal Care” formulated by the National Society for Medical Research and the “Guide for the Care and Use of Laboratory Animals” prepared by the Institute of Laboratory Animal Resources and published by the National Institutes of Health (NIH Publication No. 85-23, revised 1985).