1
|
Abstract
The concept of delaying a skin flap is well established and has been implemented into plastic surgery practice for years. Some investigators have delayed musculocutaneous flaps to improve the perforator inflow. To our knowledge, the concept of delaying a muscle flap had previously never been tested in a model with segmental pedicles. Five cats each underwent 3 sequential operations providing them with a sartorius muscle whose blood supply was a single distal pedicle. The opposite leg was used as a control. Our delayed type IV muscle flap demonstrated perfusion to the proximal tip of the sartorius muscle without necrosis or loss of muscle mass (P < 0.0001). The control showed no evidence of perfusion beyond the distal portion of the muscle when infused through the distal pedicle. The delayed flap can survive on a distal blood supply that would not be adequate in a single-stage procedure. This flap has an increased arc of rotation that may provide solutions to difficult reconstructive problems in the groin, lower abdomen, genitalia, knee, proximal leg, and might be suitable as a free flap.
Collapse
Affiliation(s)
- Ned Snyder
- Division of Plastic Surgery, The University of Texas Medical Branch, Galveston, 77555, USA
| | | | | |
Collapse
|
2
|
Harralson T, Grossi FV, Quan EE, Tecimer T, Perez-Abadia G, Anderson G, Barker JH, Maldonado C. Ischemic Preconditioning of Skeletal Muscle. Ann Plast Surg 2005; 55:216-22. [PMID: 16034256 DOI: 10.1097/01.sap.0000164578.85395.c7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The time course of the late phase of ischemic preconditioning (IPC) was determined in latissimus dorsi muscle (LDM) flaps using viability and function as the endpoints. MATERIALS AND METHODS LDM flaps from Sprague-Dawley rats were allocated into 6 groups. LDMs were preconditioned with 2 30-minute periods of ischemia separated by 10 minutes of reperfusion and subjected to a 4-hour ischemic insult after 24, 48, 72, and 96 hours from IPC. LDMs were evaluated for percent necrosis and muscle contractile function and compared with controls. RESULTS The late phase of IPC provides significant protection against necrosis up to 72 hours. Conversely, when the end point used was muscle contractile function, the protection only lasted 48 hours. CONCLUSION The time course of late-phase protection in skeletal muscle is 2-3 days. Late phase IPC appears to protect muscle flaps during the most critical time period following elevation.
Collapse
Affiliation(s)
- Thomas Harralson
- Department of Surgery, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | | | | | | | | | | | | | | |
Collapse
|
3
|
Rigatelli G, Carraro U, Barbiero M, Riccardi R, Cobelli F, Gemelli M, Rigatelli G. A review of the concept of circulatory bioassist focused on the "new" demand dynamic cardiomyoplasty: the renewal of dynamic cardiomyoplasty? Angiology 2003; 54:301-6. [PMID: 12785022 DOI: 10.1177/000331970305400305] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
After the initial enthusiasm, the dynamic cardiomyoplasty lost its reputation owing to the poor long-term results, caused by the muscular degeneration subsequent to chronic continuous electrical stimulation of the latissimus dorsi. An activity-rest stimulation protocol that avoids full transformation of the skeletal muscle, maintaining muscular properties over time, has been successfully tried. This "demand" stimulation protocol showed in humans good results improving NYHA class, ejection fraction value, and survival. The discussion about the capability of this and a unique kind of cardiocirculatory bioassist is due to be reopened. In fact, heart transplant, percutaneous circulatory-supporting device, multisites stimulation therapy, and total artificial heart have some drawbacks, one of which is the economic cost. In developing countries the more economic demand dynamic cardiomyoplasty may still play a role.
Collapse
|
4
|
Zakine G, Martinod E, Fornes P, Sapoval M, Barritault D, Carpentier AF, Chachques JC. Growth factors improve latissimus dorsi muscle vascularization and trophicity after cardiomyoplasty. Ann Thorac Surg 2003; 75:549-54. [PMID: 12607671 DOI: 10.1016/s0003-4975(02)04332-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND Dynamic cardiomyoplasty consists of wrapping the electrostimulated latissimus dorsi muscle (LDM) around the failed heart. Partial ischemia followed by atrophy of the middle and distal part of the LDM were observed in 30% of clinical cases after LDM flap elevation from its origin. In the current study, we hypothesized that local administration of growth factors at the LDM/epicardial interface could improve muscle vascularization and trophicity. METHODS In 24 sheep, dynamic cardiomyoplasty was performed using the left LDM. A multiperforated catheter was positioned at the LDM/epicardial interface for a weekly administration, during a 1-month period, of the following factors: basic fibroblast growth factor (bFGF, n = 6), vascular endothelial growth factor (VEGF, n = 6), and regenerating agent (RGTA, n = 6). Six sheep injected with phosphate-buffered saline (used for dilution of the growth factors) were used as a control group. At 3 months, angiographic, histologic, and histomorphometric studies were performed. RESULTS Angiographic studies of the animals treated with growth factors demonstrated hypervascularization due to the development of new vessels. Histomorphometric and histologic studies showed a significant increase in the number of capillaries and arterioles (100 fields/muscle) in the groups treated with bFGF (443.0 +/- 101.2, p < 0.01), RGTA (293.2 +/- 29.3, p < 0.05), and VEGF (246.5 +/- 45.9, p < 0.05), as compared with the control group (81.5 +/- 11.4). A significantly lower atrophy score was observed in the groups treated with bFGF (1.4 +/- 0.18, p < 0.05), RGTA (1.59 +/- 0.17, p < 0.05), and VEGF (1.96 +/- 0.14, NS), as compared with the control group (2.48 +/- 0.16). CONCLUSIONS Local administration at the heart/muscle interface of growth factors increases muscle vascularization and avoids muscle atrophy in an experimental cardiomyoplasty model, both of which are advantageous to the contracting LDM. The local growth factors delivery system used in this study appears efficient, easy to implant, and manipulate and safe.
Collapse
Affiliation(s)
- Gilbert Zakine
- Department of Cardiovascular Surgery, Broussais Hospital, Paris, France
| | | | | | | | | | | | | |
Collapse
|
5
|
Can Angiogenesis Induced by Chronic Electrical Stimulation Enhance Latissimus Dorsi Muscle Flap Survival for Application in Cardiomyoplasty? Plast Reconstr Surg 2003. [DOI: 10.1097/00006534-200301000-00032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
6
|
Rigatelli G, Barbiero M, Rigatelli G, Cotocni A, Riccardi R, Cobelli F, Carraro U. Cardiocirculatory bio-assist: is it time to reconsider demand dynamic cardiomyoplasty? Review and future perspectives. ASAIO J 2003; 49:24-9. [PMID: 12558303 DOI: 10.1097/00002480-200301000-00004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
In the last 15 years, dynamic cardiomyoplasty has remained an experimental procedure even after the enthusiastic short- and mid-term results, mainly because of the disappointing long-term outcome caused by muscular degeneration secondary to chronic continuous electrical stimulation of the latissimus dorsi. In Italy, a group of muscular pathologists, cardiologists, and cardiac surgeons conducted an experiment of an activity-rest stimulation protocol in humans that should avoid complete transformation of the skeletal muscle, maintaining its properties overtime. This "demand" stimulation protocol gave good results, improving New York Heart Association class, ejection fraction value, and survival. Even though dynamic cardiomyoplasty was excluded from the recent international guidelines for the management of heart failure, the discussion on the ability of this unique kind of cardiocirculatory bio-assistance is due to be reopened, thanks to the results of the new stimulation protocol. Heart transplantation, circulatory supporting devices, multisite stimulation therapy, and the total artificial heart are not always and in all countries the best solutions: the great economic cost, the numerous contraindications, the need for immunosuppression and antithrombotic therapy, and the troublesome follow up constitute important drawbacks. For patients in whom transplant surgery cannot be performed, as well as in developing countries, the nonprohibitively expensive demand dynamic cardiomyoplasty may still play a role.
Collapse
|
7
|
Woo EBC, Jarvis JC, Hooper TL, Salmons S. Avoiding ischemia in latissimus dorsi muscle grafts: electrical prestimulation versus vascular delay. Ann Thorac Surg 2002; 73:1927-32. [PMID: 12078792 DOI: 10.1016/s0003-4975(02)03587-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND Surgical mobilization of the latissimus dorsi muscle produces regional ischemic damage that may compromise its function in clinical applications such as cardiomyoplasty. We compared the effectiveness of two procedures designed to maintain blood flow throughout the mobilized muscle. METHODS Adult pigs were assigned to two experimental groups: an electrically prestimulated group (n = 10) and a vascular delay group (n = 10). In the prestimulated group the left latissimus dorsi muscle was activated in situ at 2 Hz for 24 h/d. In the vascular delay group, the intercostal perforating arteries to the left latissimus dorsi muscle were divided. Two weeks later, hyperemic blood flow was measured by means of fluorescent microspheres immediately before and after mobilizing the latissimus dorsi muscle and again after recovery for a further 2 days. RESULTS In the prestimulated group, blood flow was not significantly depressed in any region of the muscle immediately after mobilization, and blood flow increased significantly in proximal (p = 0.01), middle (p = 0.02), and distal (p = 0.007) regions following recovery. In muscles subjected to vascular delay the proximal and middle regions showed no significant changes in blood flow after mobilization or recovery, but flow in the distal region was 50% lower after mobilization (p = 0.003), and it remained significantly depressed even after recovery (p = 0.008). CONCLUSIONS Prestimulation was significantly more effective than vascular delay in preserving distal blood flow. Because it is also less invasive and initiates metabolic transformation before mobilization, this technique should allow cardiac assistance to be introduced at an earlier postoperative stage without compromising the viability of the grafted muscle.
Collapse
Affiliation(s)
- Edwin B C Woo
- Department of Cardiothoracic Surgery, Wythenshawe Hospital, Manchester, United Kingdom
| | | | | | | |
Collapse
|
8
|
Woo EBC, Tang ATM, Jarvis JC, Hasleton PS, Salmons S, Hooper TL. Improved viability of latissimus dorsi muscle grafts after electrical prestimulation. Muscle Nerve 2002; 25:679-684. [PMID: 11994961 DOI: 10.1002/mus.10099] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Surgical mobilization of the latissimus dorsi muscle (LDM) produces fiber degeneration, particularly in the distal part of the graft, that may compromise its function in clinical applications such as dynamic cardiomyoplasty. In five rats, the left LDM was stimulated continuously at 10 HZ. After 5 weeks, vessels perforating the chest wall were divided and the left LDM was mobilized as a pedicle graft based on the thoracodorsal artery. Twenty-four hours later, animals were killed and left and right LDMs were incubated with the vital stain nitroblue tetrazolium. Five control rats underwent a similar procedure without prestimulation. Mobilization of the LDM resulted in a loss of viability in the distal third of the muscle graft. This was reduced significantly by prestimulation (P = 0.006). Blood flow to the distal LDM graft is known to be augmented by electrical stimulation in situ before mobilization; the present results show that there is an associated enhancement of viability. The clinical implications of this finding are discussed.
Collapse
Affiliation(s)
- Edwin B C Woo
- Department of Cardiothoracic Surgery, Wythenshawe Hospital, Manchester, United Kingdom
- Department of Human Anatomy and Cell Biology, University of Liverpool, Sherrington Building, Ashton Street, Liverpool L69 3GE, United Kingdom
| | - Augustine T M Tang
- Department of Cardiothoracic Surgery, Southampton General Hospital, Southampton, United Kingdom
| | - Jonathan C Jarvis
- Department of Human Anatomy and Cell Biology, University of Liverpool, Sherrington Building, Ashton Street, Liverpool L69 3GE, United Kingdom
| | - Philip S Hasleton
- Department of Cardiothoracic Surgery, Wythenshawe Hospital, Manchester, United Kingdom
| | - Stanley Salmons
- Department of Human Anatomy and Cell Biology, University of Liverpool, Sherrington Building, Ashton Street, Liverpool L69 3GE, United Kingdom
| | - Timothy L Hooper
- Department of Cardiothoracic Surgery, Wythenshawe Hospital, Manchester, United Kingdom
| |
Collapse
|
9
|
Wan C, Maldonado C, Papanicolaou G, Anderson GL, Overgoor M, Kon M, Barker JH. Reducing the vascular delay period in latissimus dorsi muscle flaps for use in cardiomyoplasty. Plast Reconstr Surg 2002; 109:1630-7. [PMID: 11932607 DOI: 10.1097/00006534-200204150-00021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Although the mechanism by which vascular delay benefits skin flaps is not completely understood, this topic has been extensively studied and reported on in the literature. In contrast, little has been documented about the effects of vascular delay in skeletal muscle flaps. Recent animal studies tested the effectiveness of vascular delay to enhance latissimus dorsi muscle flap viability for use in cardiomyoplasty and found that it prevented distal flap necrosis. However, these studies did not define the optimal time period necessary to achieve this beneficial effect. The purpose of this study was to determine how many days of "delay" can elicit the beneficial effects of vascular delay on latissimus dorsi muscle flaps. To accomplish this, 90 latissimus dorsi muscles of 45 male Sprague-Dawley rats were randomly subjected to vascular delay on one side or a sham procedure on the other. After predetermined delay periods (0, 3, 7, 10, and 14 days) or a sham procedure, all latissimus dorsi muscles were elevated as single pedicled flaps based only on their thoracodorsal neurovascular pedicle. Latissimus dorsi muscle perfusion was measured using a Laser Doppler Perfusion Imager just before and immediately after flap elevation. The muscles were then returned to their original vascular beds, isolated from adjacent tissue with Silastic film, sutured into place to maintain their original size and shape, and left there for 5 days. After 5 days, the latissimus dorsi muscle flaps were dissected free, scanned again (Laser Doppler Perfusion Imager-perfusion measurements), and the area of distal necrosis was measured using digitized planimetry of magnified images. The authors' results showed that delay periods of 3, 7, 10, and 14 days significantly increased (p < 0.05) blood perfusion and decreased (p < 0.05) distal flap necrosis when compared with sham controls. On the basis of these findings, the authors conclude that in their rat latissimus dorsi muscle flap model the beneficial effects of vascular delay are present as early as 3 days. If these findings also hold true in humans, they could be useful in cardiomyoplasty by allowing surgeons to shorten the amount of time between the vascular delay procedure and the cardiomyoplasty procedure in these very sick patients.
Collapse
Affiliation(s)
- Chris Wan
- Division of Plastic and Reconstructive Surgery, Department of Surgery, University of Louisvill, KY 40292, USA
| | | | | | | | | | | | | |
Collapse
|
10
|
Alvarez JM. Dynamic cardiomyoplasty: "the truth that dare not speak its name". Ann Thorac Surg 2002; 73:346-7. [PMID: 11834057 DOI: 10.1016/s0003-4975(01)03132-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
|
11
|
Kashem A, Santamore WP, Hassan S, Chiang B, Slatert AD. Can latissimus dorsi muscle stimulation benefit heart during training period after vascular delay? ASAIO J 2001; 47:655-61. [PMID: 11730206 DOI: 10.1097/00002480-200111000-00017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
We hypothesized that a two-stage vascular delay procedure followed by 5 weeks of conditioning of the latissimus dorsi muscle (LDM) could benefit the heart during the training period and greatly increase cardiac assistance when examined with maximum potential. In mongrel dogs (n = 10), left ventricle (LV) dysfunction was induced by intracoronary injections of latex microspheres [90 +/- 2 micro diameter]. Vascular delay of the LDM was performed in one group (n = 6), whereas the other group (control, n = 4) did not undergo vascular delay. After 2 weeks, CMP was performed in all animals followed by LDM conditioning. After 5 weeks of muscle training, we examined left ventricular function at 20 Hz-4 volts, 33 Hz-4 volts, and 50 Hz-10 volts stimulation by assessing peak aortic pressure (AoP), left ventricular pressure (LVP), maximum LV +dP/dt, stroke volume (SV), stroke work (SW), stroke power (SP), and aortic flow. LDM assisted beats were compared with nonstimulated beats. LDM stimulation caused significant increases in pressure and flow in the vascular delay group. At 20 Hz-4 volts, absolute increases were LVP (10.2 +/- 0.6) mm Hg, AoP (9.8 +/- 1.7) mm Hg, SV (1.8 +/- 0.4) ml, SW (5.3 +/- 1.0) gm x m, SP (40.8 +/- 12.7) gm x m/sec, max LV dP/dt (104.8 +/- 53.2) mm Hg/sec, and peak aortic flow (0.9 +/- 0.3) L/min. At 33 Hz-4 volts, the absolute increases were LVP (13.6 +/- 1.3) mm Hg, AoP (12.1 +/- 2.4) mm Hg, SV (2.7 +/- 0.7) ml, SW (7.4 +/- 1.4) gm x m, SP (72.7 +/- 16.5) gm x m/sec, max LV dP/dt (294 +/- 19) mm Hg/sec, and peak aortic flow (1.8 +/- 0.5) L/min. At 50 Hz-10 volts, the absolute increases were LVP (17.7 +/- 0.7) mm Hg, AoP (21.1 +/- 1.9) mm Hg, SV (6.0 +/- 1.1) ml, SW (14.6 +/- 2.2) gm.m, SP (128.2 +/- 15.3) gm x m/sec, max LV dP/dt (352 +/- 62) mm Hg/sec, and peak aortic flow (3.3 +/- 0.4) l/min (p < 0.05). The percentage increases were significantly larger in the vascular delay group compared with controls at 50 Hz-10 volts LDM stimulation. By using a two-stage vascular delay procedure, LDM stimulation can provide meaningful cardiac assistance during training periods. Furthermore, brief periods of maximal potential benefit (demand cardiomyoplasty) can be achieved during the training period.
Collapse
Affiliation(s)
- A Kashem
- Department of Medicine, Temple University, Philadelphia, Pennsylvania, USA
| | | | | | | | | |
Collapse
|
12
|
Abstract
Dynamic cardiomyoplasty was proposed as an alternative surgical treatment for severe cardiomyopathies and has been performed worldwide in more than 1,000 patients. Patients indicated for this procedure are specifically those with dilated or ischemic cardiomyopathies. The ventricular function improvement observed after dynamic cardiomyoplasty derived from the direct action of synchronized skeletal muscle flap contraction and from a girdling effect that helps to reverse chamber remodeling and to decrease ventricular wall stress. Although long-term benefits of this procedure may be limited by skeletal muscle flap ischemic compromise, technological advances incorporated in the new myostimulators will possibly decrease this complication incidence. Clinical improvement has been reported as a consistent finding in cardiomyoplasty follow-up and the overall 5-year survival after this procedure ranges from 39 % to 54 %. On the other hand, the mortality after cardiomyoplasty has been significantly higher for patients in persistent New York Heart Association functional class IV, showing that this procedure needs to be indicated earlier than the heart transplantation. In this regard, only the results of an ongoing randomized trial will potentially define cardiomyoplasty influence on the survival of patients with severe heart failure. In the meantime, however, there are clearly several functional class III patients whose quality of life and exercise capacity have worsened despite the use of maximum medical therapy, justifying dynamic cardiomyoplasty indication.
Collapse
Affiliation(s)
- L F Moreira
- Heart Institute (Incor), University of São Paulo Medical School, São Paulo, SP, Brazil.
| | | |
Collapse
|
13
|
Kashem A, Santamore WP, Chiang B, Unger L, Ali AT, Slater AD. Vascular delay and intermittent stimulation: keys to successful latissimus dorsi muscle stimulation. Ann Thorac Surg 2001; 71:1866-73. [PMID: 11426760 DOI: 10.1016/s0003-4975(01)02571-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
BACKGROUND The goal of this study was to obtain physiologically significant increases in peak left ventricular (LV) systolic pressure and stroke volume with latissimus dorsi muscle (LDM) stimulation in cardiomyoplasty (CMP). We hypothesized that preserving LDM integrity by vascular delay and intermittent stimulation would significantly increase LDM cardiac assistance. METHODS In 4 control dogs and 12 dogs that had undergone a vascular delay (VD) procedure, LV dysfunction was induced by intracoronary microsphere injections. Cardiomyoplasty surgery was performed 14 days later, followed by progressive LDM conditioning. In the control dogs and in 6 of the VD dogs, the LDM was stimulated 24 hours per day (VD plus constant stimulation [CS]). In the other 6 VD dogs, LDMs were stimulated on a daily schedule of 10 hours on and 14 hours off (VD plus interrupted stimulation [IS]). Latissimus dorsi muscle stimulated beats were compared with nonstimulated beats 9 weeks later. RESULTS In the control dogs, LDM stimulation had minimal effects. In VD + CS and VD + IS, LDM stimulation increased peak LV pressure, stroke volume, stroke work, and stroke power (p < 0.05). However, these changes were greater in the VD + IS group, in which LDM stimulation increased peak aortic pressure by 17.6 +/- 1.7 mm Hg, peak LV pressure by 19.7 +/- 1.1 mm Hg, peak positive LV dp/dt by 398 +/- 144 mm Hg per second, stroke volume by 5.1 +/- 0.7 mL, stroke work by 10.9 +/- 0.9 gm.m, and stroke power by 122.7 +/- 11.6 gm.m per second (p < 0.05 compared with VD + CS). Quantitative morphometric analysis showed minimal LDM degeneration in the VD + IS group (7.5% +/- 1.1%), and VD + CS group (10.5% +/- 4.5%) compared with the control group (29.5% +/- 4.5%, p < 0.05). CONCLUSIONS VD and IS considerably increased the LV assistance with LDM stimulation. Further studies of this combined approach to CMP should be planned.
Collapse
Affiliation(s)
- A Kashem
- Division of Cardiovascular Research, Temple University, Philadelphia, Pennsylvania 19140, USA.
| | | | | | | | | | | |
Collapse
|
14
|
Singh TP, Greer K, Muzik O, Hammond RL, Stephenson LW, Di Carli MF. Assessment of Skeletal Muscle Ventricle Tissue Blood Flow Using Positron Emission Tomography. Artif Organs 2001. [DOI: 10.1046/j.1525-1594.2001.025004306.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
15
|
Singh TP, Greer K, Muzik O, Hammond RL, Stephenson LW, Di Carli MF. Assessment of Skeletal Muscle Ventricle Tissue Blood Flow Using Positron Emission Tomography. Artif Organs 2001. [DOI: 10.1046/j.1525-1594.2001.06673.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
| | | | | | | | | | - Marcelo F. Di Carli
- Department of Radiology,
- Department of Internal Medicine, Wayne State University School of Medicine; and the Positron Emission Tomography Center, Children's Hospital of Michigan, Detroit, Michigan, U.S.A
| |
Collapse
|
16
|
Barron DJ, Etherington PJ, Winlove CP, Jarvis JC, Salmons S, Pepper JR. Combination of preconditioning and delayed flap elevation: evidence for improved perfusion and oxygenation of the latissimus dorsi muscle for cardiomyoplasty. Ann Thorac Surg 2001; 71:852-61. [PMID: 11269464 DOI: 10.1016/s0003-4975(00)02445-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Atrophy and fibrosis of the distal part of the latissimus dorsi muscle (LDM) wrap is a recognized complication of cardiomyoplasty that has been attributed to ischemia. Failure of the muscle wrap contributes to the late attrition seen in clinical cardiomyoplasty. In this study we examined the role of two-staged mobilization and of preconditioning by electrical stimulation on the regional perfusion and oxygenation of the LDM. METHODS In a rabbit model (n = 36) the LDM was preconditioned as follows: group A muscles received preconditioning in situ; group B muscles were partially mobilized by dividing the intercostal perforators and then preconditioned; and group C muscles were completely mobilized and wrapped around a silicone-rubber mandrel before conditioning. Controls received no conditioning. The preconditioning regimen consisted of 2 weeks of continuous stimulation at 2.5 Hz. At completion of preconditioning the muscles were fully mobilized and mounted on a muscle-testing apparatus. Purpose-built microelectrodes measured regional PO2 and perfusion using a diffusible gas tracer technique. Muscles were weighed and processed for fiber typing and capillary counting. RESULTS All preconditioned muscles demonstrated fiber transformation, with increased fatigue resistance. Perfusion of preconditioned muscles both at rest and during contraction was higher than control in the proximal part of the muscle. Distal regions of group B muscles had higher perfusion and capillary density than any other group (p < 0.05). Distal regions of group C had the lowest perfusion and capillary density, and showed muscle atrophy and histologic evidence of necrosis. During fatigue testing there was a decrease in the PO2 in the distal regions of the control and group C muscles (p < 0.05), whereas it was maintained at resting levels in both group A and B muscles. CONCLUSIONS Conditioning in situ improves perfusion of the distal LDM and prevents a fall in tissue PO2 during contraction. Two-stage mobilization further improves distal perfusion and capillary density. In contrast, shortterm elevation followed by conditioning produces impaired distal perfusion, decrease in PO2, and fiber necrosis in the distal muscle. The present study suggests that partial mobilization of the LDM performed at the same time as placement of electrodes for preconditioning may prepare the LDM better for the demands of cardiomyoplasty.
Collapse
Affiliation(s)
- D J Barron
- Department of Cardiac Surgery, National Heart and Lung Institute, London, United Kingdom.
| | | | | | | | | | | |
Collapse
|
17
|
Bardoel JW, Stadelmann WK, Perez-Abadia GA, Galandiuk S, Zonnevijlle ED, Maldonado C, Stremel RW, Tobin GR, Kon M, Barker JH. Dynamic rectus abdominis muscle sphincter for stoma continence: an acute functional study in a dog model. Plast Reconstr Surg 2001; 107:478-84. [PMID: 11214064 DOI: 10.1097/00006534-200102000-00025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Fecal stomal incontinence is a problem that continues to defy surgical treatment. Previous attempts to create continent stomas using dynamic myoplasty have had limited success due to denervation atrophy of the muscle flap used in the creation of the sphincter and because of muscle fatigue resulting from continuous electrical stimulation. To address the problem of denervation atrophy, a stomal sphincter was designed using the most caudal segment of the rectus abdominis muscle, preserving its intercostal innervation as well as its vascular supply. The purpose of the present study was to determine whether this rectus abdominis muscle island flap sphincter design could maintain stomal continence acutely. In this experiment, six dogs were used to create eight rectus abdominis island flap stoma sphincters around a segment of distal ileum. Initially, the intraluminal stomal pressures generated by the sphincter using different stimulation frequencies were determined. The ability of this stomal sphincter to generate continence at different intraluminal bowel pressures was then assessed. In all cases, the rectus abdominis muscle sphincter generated peak pressures well above those needed to maintain stomal continence (60 mmHg). In addition, each sphincter was able to maintain stomal continence at all intraluminal bowel pressures tested.
Collapse
Affiliation(s)
- J W Bardoel
- Department of Surgery, University of Louisville, KY 40292, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Inaba H, Kaneko Y, Ohtsuka T, Ezure M, Tanaka K, Ueno K, Takamoto S. Minimal damage during endoscopic latissimus dorsi muscle mobilization with the harmonic scalpel. Ann Thorac Surg 2000; 69:1399-401. [PMID: 10881812 DOI: 10.1016/s0003-4975(00)01136-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
BACKGROUND To reduce wound-related complications, a video-assisted surgical technique has been adopted for the mobilization of the latissimus dorsi muscle. We postulated that thermal damage to the muscle might be minimized by using a Harmonic Scalpel instead of electrocautery during this procedure. METHODS Canine latissimus dorsi muscles were mobilized through a small incision, assisted by a videoscope. In 6 dogs, dissection with electrocautery was used to mobilize the latissimus dorsi muscle. In 6 other dogs, the Harmonic Scalpel was used. We compared operation times, wound infection rates, histologic changes in the muscles, and ease of handling between these groups. RESULTS The operation time was significantly shorter in the Harmonic Scalpel group than in the electrocautery group (61.5 versus 106.5 minutes, p = 0.00014). The Harmonic Scalpel caused less histologic damage to the mobilized muscles and produced less vision-obscuring smoke. CONCLUSIONS The Harmonic Scalpel shortens the operation, minimizes muscle damage, and facilitates the performance of video-assisted latissimus dorsi muscle mobilization.
Collapse
Affiliation(s)
- H Inaba
- Department of Cardiothoracic Surgery, Faculty of Medicine, University of Tokyo, Japan
| | | | | | | | | | | | | |
Collapse
|
19
|
Carroll SM, Carroll CM, Stremel RW, Heilman SJ, Steffen JM, Tobin GR, Barker JH. Vascular delay and administration of basic fibroblast growth factor augment latissimus dorsi muscle flap perfusion and function. Plast Reconstr Surg 2000; 105:964-71. [PMID: 10724256 DOI: 10.1097/00006534-200003000-00020] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Ischemia of the distal latissimus dorsi muscle flap occurs when the entire muscle is acutely elevated. Although this level of ischemia may not be critical if the muscle is to be used as a conventional muscle flap, the ischemia causes decreased distal muscle function if it is used for dynamic muscle flap transfer. This experiment was designed to determine whether or not the administration of exogenous basic fibroblast growth factor (bFGF), combined with a sublethal ischemic insult (i.e., vascular delay), would further augment muscle perfusion and function. Both latissimus dorsi muscles of nine canines were subjected to a bipedicle vascular delay procedure immediately followed by thoracodorsal intraarterial injection of 100 microg of bFGF on one side and by intraarterial injection of vehicle on the other. Ten days later, both latissimus dorsi muscles were raised as thoracodorsally based island flaps, with perfusion determined by laser-Doppler fluximetry. The muscles were wrapped around silicone chambers, simulating cardiomyoplasty, and stimulating electrodes were placed around each thoracodorsal nerve. The muscles were then subjected to an experimental protocol to determine muscle contractile function. At the end of the experiment, latissimus dorsi muscle biopsies were obtained for measurement of bFGF expression. The results demonstrated that the administration of 100 microg of bFGF immediately after the vascular delay procedure increases expression of native bFGF. In the distal and middle muscle segments, it also significantly increased muscle perfusion by approximately 20 percent and fatigue resistance by approximately 300 percent. The administration of growth factors may serve as an important adjuvant to surgical procedures using dynamic muscle flap transfers.
Collapse
Affiliation(s)
- S M Carroll
- Department of Surgery, School of Medicine, University of Louisville, KY, USA
| | | | | | | | | | | | | |
Collapse
|
20
|
Abstract
This paper looks at the prospects for new surgical solutions to the problem of end-stage heart failure based on cardiac assistance from skeletal muscle. The current status of the main biological approaches, cardiomyoplasty, aortomyoplasty, and the skeletal muscle ventricle, are discussed, followed by a consideration of some of the important basic issues that need to be addressed if these techniques are to achieve their full potential. Although there is a review element to the paper, the main emphasis is on the work of our own research group and collaborating workers.
Collapse
Affiliation(s)
- S Salmons
- Department of Human Anatomy and Cell Biology, University of Liverpool, UK.
| |
Collapse
|
21
|
Ali AT, Santamore WP, Chiang BY, Dowling RD, Tobin GR, Slater AD. Vascular delay of the latissimus dorsi provides an early hemodynamic benefit in dynamic cardiomyoplasty. Ann Thorac Surg 1999; 67:1304-11. [PMID: 10355402 DOI: 10.1016/s0003-4975(99)00186-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVES Dynamic cardiomyoplasty (CMP) as a surgical treatment for chronic heart failure improves functional class status for most patients. However, significant hemodynamic improvement with latissimus dorsi muscle (LDM) stimulation has not been consistent. The current protocols do not allow early LDM stimulation after CMP surgery. We hypothesized that vascular delay of LDM would increase myocardial assistance after CMP and allow early (48-h) LDM stimulation after CMP. METHODS Mongrel dogs (n = 24) were divided in four groups: 1) controls (n = 6), single-stage CMP; 2) Group ES (n = 6), single-stage CMP with early LDM stimulation beginning 48 h, postoperatively; 3) Group VD (n = 6), vascular delay of the LDM followed by CMP without early LDM stimulation, and 4) Group VDES (n = 6), vascular delay of LDM (14-18 days), followed by CMP with early stimulation (48 h postoperatively). Two weeks after CMP, global cardiac dysfunction was induced by injecting microspheres into the left coronary artery. LDM-assisted (S) beats were compared with nonstimulated beats (NS) by measuring aortic pressure (AoP), LV pressure, aortic flow, and by calculating first derivative of LV contraction (+/-dP/dt), stroke volume (SV), and stroke work (SW). RESULTS In ES, LDM stimulation had no effect on the hemodynamic parameters. In the other groups, LDM stimulation significantly (p < 0.05) increased AoP, LVP, dP/dt, SV, and SW. However, these increases were much larger in VD and VDES. In VD, LDM stimulation increased peak AoP by 21.5+/-3.8 mm Hg, LVP by 22.1+/-4.1 mm Hg, dP/dt by 512+/-163 mm Hg/sec, SV by 10.4+/-2.3 mL, and SW by 22.1+/-5.4 g/m(-1). Similarly, in VDES, LDM stimulation increased peak AoP by 24.1+/-4.7 mm Hg, LVP by 26.2+/-4.3 mm Hg, dP/dt by 619+/-47 mm Hg/sec, SV by 6.5+/-0.7 mL, and SW by 16.7+/-4.1 g/m(-1). CONCLUSIONS In dogs with global LV dysfunction, CMP after vascular delay resulted in a significant improvement in hemodynamic function measured 2 weeks after surgery. This improvement was not provided by single-stage CMP with or without early stimulation. Vascular delay of the LDM before surgery may play an important role for early benefit after CMP, shorten the overall muscle training period, as well as increase hemodynamic response to LDM stimulation.
Collapse
Affiliation(s)
- A T Ali
- Jewish Hospital Cardiovascular Research Center, Department of Surgery, University of Louisville School of Medicine, Kentucky, USA
| | | | | | | | | | | |
Collapse
|
22
|
Abstract
BACKGROUND Distal ischemia and necrosis of the dog latissimus dorsi muscle flap used in experimental cardiomyoplasty have been reported. However, little information on the intramuscular vascular anatomy of the dog latissimus dorsi is available. It is unclear whether there are any anatomic factors relating to the muscle flap ischemia and necrosis, and whether the dog latissimus dorsi is a suitable experimental model. METHODS To study the intramuscular vascular territories in the dog latissimus dorsi muscle, and to compare the intramuscular vasculature of the dog with that of the human, 5 fresh dog cadavers and 7 fresh human cadavers were injected with a mixture of lead oxide, gelatin, and water (200 mL/kg) through the carotid artery. Both the dog and the human latissimus dorsi muscles and neurovascular pedicles were dissected and radiographed. The intramuscular vascular anatomy of the latissimus dorsi muscles was compared. RESULTS Radiographs demonstrate clearly that the pattern of latissimus dorsi intramuscular anastomoses between branches of the thoracodorsal artery and the perforators of posterior intercostal arteries in the proximal half of the muscle are different between the dog and the human. In the dog muscle, vascular connections between the thoracodorsal artery and the posterior intercostal arteries are formed by reduced-caliber choke arteries, whereas four to six true anastomoses without a change in caliber between them are found in the human muscle. The portion of the latissimus dorsi muscle supplied by the dominant thoracodorsal vascular territory was 25.9% +/- 0.3% in the dog and 23.9% +/- 0.5% in the human. For further comparison, an extended vascular territory in the latissimus dorsi muscle was demonstrated, including both the thoracodorsal territory and the posterior intercostal territories. The area of the extended vascular territory was 52% +/- 0.5% of the total muscle. CONCLUSIONS The dog latissimus dorsi model may not be a perfect predictor of the behavior of the human latissimus dorsi muscle flap in cardiomyoplasty.
Collapse
Affiliation(s)
- D Yang
- Department of Anatomy, Dalhousie University, Halifax, Nova Scotia, Canada
| | | |
Collapse
|
23
|
Ali AT, Chiang BY, Santamore WP, Dowling RD, Slater AD. Preconditioning of the latissimus dorsi muscle in cardiomyoplasty: vascular delay or chronic electrical stimulation. Eur J Cardiothorac Surg 1998; 14:304-10. [PMID: 9761442 DOI: 10.1016/s1010-7940(98)00157-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES In standard single stage cardiomyoplasty (CMP), the latissimus dorsi muscle (LDM) is not preconditioned prior to surgery. We hypothesized that latissimus dorsi preconditioning by vascular delay or by chronic electrical stimulation would result in an improved LV hemodynamic function early (14 days) after CMP. METHODS Mongrel dogs had preconditioning of the latissimus dorsi by a vascular delay procedure followed by CMP 14-18 days later (group I VD). Dogs in group II underwent 4 weeks of chronic stimulation (CS) of the latissimus dorsi (2 V/30 Hz, six bursts/min) followed by CMP. The latissimus dorsi muscle was fully stimulated from 48 h after cardiomyoplasty in both groups (2 V/30 Hz, three bursts/min). Two weeks after myoplasty, injecting 2.0-3.0 x 10(5) 90 microm latex microspheres in the left main coronary artery induced global cardiac dysfunction. Hemodynamic function was then evaluated for latissimus dorsi muscle assisted (S) beats and non-stimulated beats (NS) in each group by measuring peak systolic aortic pressure (AOP), left ventricular pressure (LVP) and end diastolic pressure (LVEDP), and by calculating maximum and minimum dP/dt. RESULTS Dogs with vascular delay of the latissimus dorsi showed a marked increase for all hemodynamic indices (AOP: 23.9+/-2.5%, LVP: 23.5+/-2.2%, max dP/dt: 49.4+/-3.3%) for LDM assisted (S) beats compared to non-stimulated beats (P < 0.001). Animals with chronic electrical training did not demonstrate a significant increase in any hemodynamic parameter with LDM stimulation. CONCLUSION Preconditioning the LDM may play an important role in providing early cardiac assistance in CMP. Preconditioning the LDM with vascular delay resulted in improving performance of the LDM with consistent increases in LV hemodynamics. This was not observed after preconditioning with chronic electrical stimulation. Vascular delay of the latissimus dorsi can significantly improve muscle performance in CMP and could provide hemodynamic assistance early after surgery.
Collapse
Affiliation(s)
- A T Ali
- Jewish Hospital Cardiothoracic Surgical Research Institute, Department of Surgery, University of Louisville School of Medicine, KY, USA
| | | | | | | | | |
Collapse
|
24
|
Carroll CM, Carroll SM, Schuschke DA, Barker JH. Augmentation of skeletal muscle flap survival using platelet derived growth factor. Plast Reconstr Surg 1998; 102:407-15. [PMID: 9703077 DOI: 10.1097/00006534-199808000-00018] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Distal muscle flap ischemia and necrosis is a recognized complication of acute elevation of large skeletal muscle flaps. The aim of this study was to investigate whether the angiogenic properties of platelet derived growth factor (PDGF) could be used to augment skeletal muscle flap survival through the induction of new blood vessel formation before flap elevation. We compared this form of flap augmentation with that achieved by subjecting the muscle to a bipedicled vascular delay procedure. The animal model used was the latissimus dorsi muscle of the male homozygous (hr/hr) hairless mouse. Four groups of animals were investigated in this study (n = 10 per group). Group 1 was the control group in which the entire muscle was elevated as a thoracodorsally based island flap. In group 2, the muscle was subjected to a bipedicled vascular delay procedure. In group 3, the muscle was treated with 500 microg of recombinant human platelet derived growth factor BB. In group 4, the muscle was treated with placebo. Ten days later the entire latissimus dorsi muscle was elevated as a thoracodorsally based island flap in groups 2, 3, and 4. Percentage muscle flap survival was quantitated in all groups 5 days after elevation of the entire muscle. Angiogenesis was then quantitated by analyzing capillary to muscle fiber ratios after alkaline phosphatase staining of representative latissimus dorsi muscle samples from the proximal, middle, and distal flap segments. Percentage muscle flap survival was significantly better in PDGF treated muscles when compared with the vascularly delayed muscles (p < 0.001). Histologic analysis of latissimus dorsi muscle flaps demonstrated a significantly greater number of capillaries in the middle (p < 0.001) and distal (p < 0.001) flap segments of PDGF-treated flaps when compared with the vascularly delayed flaps. Treatment of skeletal muscle with PDGF before flap creation resulted in survival of the entire muscle flap. Our results suggest that this survival may be secondary to PDGF-induced angiogenesis.
Collapse
Affiliation(s)
- C M Carroll
- Department of Surgery, and the Center for Applied Microcirculatory Research, University of Louisville, KY 40292, USA
| | | | | | | |
Collapse
|
25
|
Carroll SM. Regional perfusion and oxygenation in the pedicled latissimus dorsi muscle flap. BRITISH JOURNAL OF PLASTIC SURGERY 1997; 50:670. [PMID: 9613420 DOI: 10.1016/s0007-1226(97)90526-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
|
26
|
Chiang BB, Ali AT, Storey J, Riordan C, Ballen J, Montgomery W, Slater AD, Santamore WP. Variable effects of cardiomyoplasty on left ventricular function. Artif Organs 1997; 21:1277-83. [PMID: 9423979 DOI: 10.1111/j.1525-1594.1997.tb00488.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Cardiomyoplasty (CMP) has been considered as a possible treatment for patients with heart failure. Symptomatic improvements occur almost uniformly among survivors with CMP, but changes in left peak ventricular systolic pressure (PVSP) and stroke volume vary in patients. This study examined whether there is variability present shortly after cardiomyoplasty surgery. Cardiomyoplasty was performed in 11 mongrel dogs with normal ventricular function. Nine to twelve days after CMP, left ventricular (LV) function was evaluated by simultaneously measuring LV volume (conductance catheter) and pressure (Millar catheter). The latissimus dorsi muscle (LDM) was stimulated synchronously with ventricular systole in a ratio of 1:4 to 1:7 to avoid muscle fatigue. Data were analyzed on a beat by beat basis. The PVSP, and maximum dP/dt (+dP/dt) increased, but the absolute value of minimum dP/dt (-dP/dt) decreased in stimulated beats in 7 dogs while 4 dogs did not respond. The net changes in stimulated beats versus nonstimulated beats of PVSP were 6.1 +/- 1.8 mm Hg (4.3%), of stroke work was 4.5 +/- 1.9 gm x m (29.5%), of +dP/dt was 185 +/- 47 mm Hg/s (8%), and of -dP/dt was 168 +/- 43 mm Hg/s (7.8%) (p < 0.05) for all these net changes in the responding group while these variations were not significant in the nonresponding group. From the results of our study, active LDM assist improves left ventricular systolic function, occurring in only 7 of 11 experiments. This improvement is inconsistent and varied individually. The integrity of the LDM, tightness of wrapping, and adhesions might contribute to the variability which is present early after surgery and before the LDM is converted into a fatigue resistance muscle.
Collapse
Affiliation(s)
- B B Chiang
- Department of Surgery, University of Louisville School of Medicine, Kentucky, USA
| | | | | | | | | | | | | | | |
Collapse
|
27
|
Stremel RW, Barker JH. Reply. Ann Thorac Surg 1997. [DOI: 10.1016/s0003-4975(97)00987-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
28
|
|
29
|
Chekanov VS, Rieder MA, Tchekanov GV, Smith LM, Eisenstein R, Schmidt DH. Comparison of different regimens of electrical stimulation applied to nonmobilized and newly mobilized latissimus dorsi muscle. J Card Surg 1997; 12:343-53. [PMID: 9635273 DOI: 10.1111/j.1540-8191.1997.tb00149.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We investigated the possibility of preventing further aggravation of muscle ischemia and necrosis in newly mobilized, unconditioned latissimus dorsi muscle (LDM) by utilizing short increments of stimulation with intervening rest periods. Adult St. Croix sheep (N = 12) weighing 30 +/- 8 kg were used in this study. Fatigue tests (30 min) using different stimulation regimens before and after LDM mobilization were performed on all animals; the length of time to return to baseline levels was also measured. Our investigation yielded results that contradict the conventional wisdom that any electrical stimulation damages newly mobilized LDM and will cause a considerable decrease in contractile force (CF). Stimulation regimens using continuous contractions at 30 and 60 contractions per minute (CPM) for 30 minutes were damaging to the LDM. CF also dropped significantly and returned slowly to baseline values: at 60 CPM, CF dropped to 50 +/- 4% and did not return to baseline even after 90 minutes of rest; at 30 CPM, CF dropped to 61 +/- 4% and baseline was restored after 80 minutes of rest. Electrical stimulation using continuous contractions at a slower rate (15 CPM) was tolerable, although a 23% decrease in CF was noted (p < 0.05 when compared to 60 CPM). These results did not satisfy us that such a regimen would be useful for cardiac assistance immediately after cardiomyoplasty. The work-rest regimen at 30 CPM also gave poor results: CF decreased to 75 +/- 2% and baseline was restored after 80 minutes of rest. Promising results were seen when utilizing a work-rest regimen at 15 CPM. The newly mobilized LDM showed no visible signs of fatigue: CF decreased minimally to 92 +/- 3% (p < 0.05 when compared to 30 CPM), and light microscopic analysis of biopsies revealed no morphological damage exceeding that typically seen after subtotal mobilization. Such results open avenues for future investigations: beginning electrical stimulation immediately after cardiomyoplasty (using a single impulse and a slow rate of contraction); decreasing the length of time necessary to obtain full cardiac assistance; and beginning partial cardiac assistance immediately after cardiomyoplasty (if needed) for approximately 30 minutes several times a day.
Collapse
Affiliation(s)
- V S Chekanov
- Sinai Samaritan Medical Center, Milwaukee Heart Project, WI 53201-0342, USA.
| | | | | | | | | | | |
Collapse
|