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Ashrafian H, Darzi A, Athanasiou T. Autobionics: a new paradigm in regenerative medicine and surgery. Regen Med 2010; 5:279-88. [PMID: 20210587 PMCID: PMC3715838 DOI: 10.2217/rme.10.2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The concept of bionics was developed 50 years ago and represented the development of engineering and technology based on natural biological systems. Traditional applications of bionics in healthcare include artificial bionic organs that apply engineering principles to replace or augment physiological functions by integrating electronic, mechanical or electromechanical components to inherent body tissues/organs (we term this as 'exobionics'). Recently, there has been a new wave of bio-inspired treatments that act through the reorganization of the existing biological organs in an individual to enhance physiology. Here, the technology does not replace biological tissue, but rather applies engineering principles to replace or augment physiological functions by the rearrangement and manipulation of inherent tissue/organs; we term this autobionics. Examples include: dynamic cardiomyoplasty (artificial heart pump using skeletal muscle), the Ross procedure (pulmonary autograft), dynamic graciloplasty (artificial sphincter) and metabolic gastric bypass (rearranging the gastrointestinal tract to modify gut- and pancreatic-hormone release). Autobionic therapies can be classified into dynamic, static and metabolic procedures. This results in tissue redesignation (one tissue used in place of another), tissue replacement and systems reorganization (rearranging inherent organ/tissue anatomy). In some cases autobionic procedures can enhance physiological function beyond normality and represents a new era in bio-inspired versatility.
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Affiliation(s)
- Hutan Ashrafian
- Department of Surgery & Cancer, Imperial College London at St Mary's Hospital, Praed Street, London, W2 1NY, UK.
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Cheng A, Nguyen TC, Malinowski M, Langer F, Liang D, Daughters GT, Ingels NB, Miller DC. Passive Ventricular Constraint Prevents Transmural Shear Strain Progression in Left Ventricle Remodeling. Circulation 2006; 114:I79-86. [PMID: 16820650 DOI: 10.1161/circulationaha.105.001578] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Background—
Passive ventricular constraint provides external cardiac support to reduce left ventricular (LV) wall stress and myocardial stretch, which are primary determinants of LV remodeling. Altered wall strain results in cytokine and reactive oxygen species production, which, in turn, stimulates apoptosis and extracellular matrix disruption and could be an important trigger for adverse global LV dilatation and remodeling. The effects of the Acorn cardiac support device (CSD) on regional transmural LV wall strains, however, remain unknown.
Methods and Results—
Thirty-three sheep had transmural radiopaque beadsets surgically inserted into the anterior basal and lateral equatorial LV walls, with additional markers silhouetting the left ventricle. Eight animals had CSD implanted (myocardial infarction [MI]+CSD). One week thereafter, the MI+CSD group and 10 animals without CSD (MI) underwent posterior LV infarction by snaring obtuse marginal coronary arteries. Fifteen animals (Sham) had no infarction or CSD. 4D marker dynamics were measured with biplane videofluoroscopy 1 and 8 weeks postoperatively. LV volumes, sphericity index, and transmural circumferential, longitudinal, and radial systolic strains were analyzed. Compared with Sham, infarction (MI) dilated the heart, reduced sphericity index (LV length/width), and increased longitudinal–radial shear strains in the inner half of both the anterior and lateral LV walls. CSD prevented this shear strain perturbation, minimized LV end diastolic volume increase, and augmented the LV sphericity index.
Conclusions—
Prophylactic CSD prevented infarct-induced shear strain progression not only in myocardium adjacent to, but also remote from, the infarct. CSD also prevented LV dilatation and sphericalization. By attenuating shear strain abnormalities, CSD could prevent the heart from entering into a positive feedback loop of further LV dilatation and exaggeration of LV wall stress and may reduce biochemical triggers portending adverse LV remodeling.
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Affiliation(s)
- Allen Cheng
- Department of Cardiothoracic Surgery, Stanford University School of Medicine, 300 Pasteur Dr, Stanford, California 94305-5247, USA
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Magovern JA, Teekell-Taylor L, Mankad S, Dasika U, McGregor W, Biederman RWW, Yamrozik J, Trumble DR. Effect of a Flexible Ventricular Restraint Device on Cardiac Remodeling after Acute Myocardial Infarction. ASAIO J 2006; 52:196-200. [PMID: 16557108 DOI: 10.1097/01.mat.0000199751.51424.78] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The effects of a flexible ventricular restraint device on left ventricular (LV) dilatation and hypertrophy after transmural infarction are examined in an ovine model. Left ventricular remodeling and dilatation occurs after extensive myocardial infarction. A flexible ventricular restraint made from a nitinol mesh was evaluated in adult female sheep (n=14). Cardiac magnetic resonance imaging scans and hemodynamic measurements were completed before and 6 weeks after anterior myocardial infarction. Treatment animals (n=7) received passive ventricular restraint concurrently with LV infarction; the others (n=7) served as controls. Increases in LV end-diastolic volume index were significantly less in the restraint group than in controls (0.20+/-0.41 vs 0.83+/-0.50 ml/kg, p<0.03). End-systolic volumes increased less in treatment animals (0.43+/-0.28 vs 0.90+/-0.38 ml/kg, p<0.03). Control hearts showed an increase in LV mass after infraction, whereas LV mass decreased in restrained hearts (0.14+/-0.19 vs -0.25+/-0.36 g/kg, p<0.03). Hemodynamic studies showed similar changes after infarction for the control and the device group. Gross and microscopic examination showed no device-induced epicardial injury. A flexible ventricular restraint device attenuated remodeling after acute myocardial infarction in sheep.
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Affiliation(s)
- James A Magovern
- Department of Cardiovascular and Thoracic Surgery, Allegheny General Hospital, Pittsburgh, PA 15212, USA
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Magovern JA. Experimental and Clinical Studies with the Paracor Cardiac Restraint Device. Semin Thorac Cardiovasc Surg 2005; 17:364-8. [PMID: 16428045 DOI: 10.1053/j.semtcvs.2005.09.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/22/2005] [Indexed: 11/11/2022]
Abstract
Progressive cardiac enlargement is a consequence of congestive heart failure (CHF) and a cause of further deterioration. Cardiac restraint devices are intended to interrupt and reverse this process, thereby improving the natural history of CHF. The Paracor restraint device is made from a superelastic nitinol mesh that exerts a small but continuous epicardial force to relieve left ventricular (LV) wall stress and to limit LV dilation. Animal studies have used various heart failure models. The data show the device reduces LV dilation after infarction, preserves LV contractility with rapid pacing, and avoids diastolic constriction in the embolization model. Ten patients in Europe and 10 in the United States have been implanted through a small thoracotomy incision without the use of cardiopulmonary bypass. Changes in LV size, functional status, and exercise performance have been measured, but the detailed data have not yet been presented or published. The device remains experimental, pending completion of additional clinical trials.
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Affiliation(s)
- James A Magovern
- Department of Cardiovascular and Thoracic Surgery, Allegheny General Hospital, Pittsburgh, PA 15212, USA.
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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.
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Affiliation(s)
- Thomas Harralson
- Department of Surgery, University of Louisville School of Medicine, Louisville, KY 40202, USA
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Sabbah HN. Global Left Ventricular Remodeling with the Acorn Cardiac Support Device: Hemodynamic and Angiographic Findings in Dogs with Heart Failure. Heart Fail Rev 2005; 10:109-15. [PMID: 16258718 DOI: 10.1007/s10741-005-4638-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Preventing progressive left ventricular (LV) remodeling is paramount in the treatment of heart failure. In recent years, several surgical approaches have been implemented with the objective of improving LV function through amelioration of progressive LV remodeling. These included surgical reduction of LV size, the so-called Batista procedure, dynamic cardiomyoplasty and mitral valve repair to limit or eliminate functional mitral regurgitation. While the Batista procedure and dynamic cardiomyoplasty have for all practical purposes been abandoned, the lessons learned from these procedures gave rise to a new generation of devices aimed at preventing progressive LV dilation and restoring LV shape by passive mechanical containment of the failing LV. One such device is the Acorn Cardiac Support Device (CSD) or the CorCap. Studies in dogs with intracoronary microembolization-induced moderate and advanced heart failure have shown that long-term monotherapy with the CSD not only prevents progressive LV dilation but, in effect, partially reverses this phenotype. These studies have also shown that the CSD restores, albeit in part, progressive LV chamber sphericity and attenuates functional mitral regurgitation. These benefits were accompanied by improvement in global LV function along with improvements of remodeling at the cellular level. The findings were largely responsible for initiating safety and feasibility clinical trials with the CSD and ultimately, the initiation of the Acorn efficacy trial that was completed in 2004. This review will focus on studies conducted in dogs with heart failure and, specifically on hemodynamic, angiographic and echocardiographic results from these studies that provided support for the CSD as a successful technology targeting "reverse LV remodeling" for the treatment of heart failure.
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Affiliation(s)
- Hani N Sabbah
- Department of Medicine, Division of Cardiovascular Medicine, Henry Ford Heart and Vascular Institute, Henry Ford Health System, Detroit, Michigan, USA.
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Kaulbach HG, Lorusso R, Bolotin G, Schreuder JJ, van der Veen FH. Effects of chronic cardiomyoplasty on ventricular remodeling in a goat model of chronic cardiac dilatation: part 2. Ann Thorac Surg 2002; 74:514-21. [PMID: 12173838 DOI: 10.1016/s0003-4975(02)03707-4] [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: 11/21/2022]
Abstract
BACKGROUND Reduction of ventricular dilatation, rather than direct improvement of pump function, has been suggested to be the main working mechanism of dynamic cardiomyoplasty (CMP). This working mechanism was examined in the goat using a chronic cardiac dilatation model induced by the creation of a cervical arteriovenous shunt and submitted to passive and active CMP. METHODS Fourteen female goats underwent surgical creation of a shunt between the left carotid artery and the jugular vein. Seven goats had no additional operation (control group). The other 7 goats (CMP group) underwent CMP approximately 8 weeks after the creation of the shunt. The wrapped left latissimus dorsi muscle was left unstimulated for 2 weeks, and subsequently stimulated electrically for a 3-month period, using a 1:4 muscle-to-heart contraction ratio. Hemodynamic measurements included heart catheterization and determination of left ventricular (LV) pressure-volume relations by means of the conductance catheter method at baseline, after 8 weeks (only in the CMP group), and after 5 months. Transthoracic echocardiography was performed just before opening the AV shunt and every 2 weeks thereafter. RESULTS Significant ventricular enlargement, as well as persistent increase in filling pressures, were observed after 8 weeks. Animals in the control group dilated further beyond 2 months (LV end-diastolic diameter from 39 +/- 2 to 67 +/- 6 mm). In contrast, the ongoing LV dilatation process was stopped by passive CMP, and LV end-diastolic diameter significantly decreased after electrical activation of the wrapped skeletal muscle (from 63 +/- 7 to 42 +/- 6 mm). Cardiomyoplasty also significantly increased the slope of the end-systolic pressure-volume relation (elastance) when compared with pre-CMP values (from 0.9 +/- 0.2 to 1.7 +/- 0.5 mm Hg/mL), which indicated an improvement of the LV contractile state. No significant hemodynamic effects could be observed at the tuned stimulation settings on a beat-to-beat basis during electrical muscle stimulation. CONCLUSIONS The contribution of CMP to LV dimension and contractility appeared to be either passive or active, and this study suggests the importance of stimulating the latissimus dorsi muscle to enhance the girdling effects of the wrapped latissimus dorsi muscle and to improve LV contractility.
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Affiliation(s)
- Hans G Kaulbach
- Department of Cardiac Surgery, Bundes Krankenhaus, Koblenz, Germany
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Monnet E. Adynamic cardiomyoplasty: effect on cardiac efficiency and contractile reserve in dogs with adriamycin-induced cardiomyopathy. J Card Surg 2002; 17:60-9. [PMID: 12027129 DOI: 10.1111/j.1540-8191.2001.tb01221.x] [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: 11/28/2022]
Abstract
The girdling effect of the skeletal muscle wrap seems to be the primary mechanism of action of cardiomyoplasty. It is associated with a myocardial sparing effect. Myocardial sparing effect has been shown with an active muscle wrap or an active muscle wrap acutely turned "OFF". The purpose of the study was to evaluate the effect of a passive skeletal muscle wrap on cardiac energetics parameters and contractile reserve in a canine model of cardiomyopathy. Six dogs with adriamycin-induced cardiomyopathy were studied. Three dogs underwent right latissimus dorsi adynamic cardiomyoplasty and 3 served as controls. Cardiac and coronary sinus catheterizations were performed at 0 and 6 weeks. A dobutamine stress test was performed at 6 weeks. Myocardial oxygen consumption was not reduced in the cardiomyoplasty group (139.20+/-86.90 Joules/min) compared to the control group (95.10+/-12.60 Joules/min, P = 0.27) at 6 weeks. Mechanical cardiac efficiency was increased in the cardiomyoplasty group (33.15+/-4.40%) compared to the control group (24.50+/-2.70%, P = 0.049) at 6 weeks. Left ventricular end diastolic diameter index was reduced in the cardiomyoplasty group (38.00+/-1.70 mm/m2) compared to the control group (46.30+/-1.55 mm/m2, P = 0.049) at 6 weeks. Indices of diastolic function -dp/dt, and tau were not significantly affected by adynamic cardiomyoplasty. Max dp/dt was increasing more in the cardiomyoplasty group than in the control group (P = 0.07) during dobutamine stress test. Mechanical cardiac efficiency was better preserved by the adynamic cardiomyoplasty. Myocardial contractile reserve might be better preserved with cardiomyoplasty.
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Affiliation(s)
- E Monnet
- Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins 80523, USA
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De Angelis K, Leirner AA, Irigoyen MC, Cestari IA. Nonstimulated cardiomyoplasty improves hemodynamics in myocardial-infarcted rats. Artif Organs 2001; 25:939-43. [PMID: 11903150 DOI: 10.1046/j.1525-1594.2001.06907.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Cardiomyoplasty has been proposed as an alternative surgical treatment for congestive heart failure. The girdling effect of the muscle wrap is believed to reduce diastolic wall stress. We tested the hypothesis that nonstimulated or passive cardiomyoplasty (CDM) would reduce hemodynamic deficits in rats with experimentally induced myocardial infarction (MI). Four groups of animals were studied: intact (C, n = 6), CDM (n = 6), MI by ligation of the left coronary artery (n = 6), and left latissimus dorsi CDM performed 14 days post-MI (MI + CDM, n = 6). All groups were studied 8 weeks after MI and/or CDM or from the beginning of the experiment in controls. MI rats had a lower mean arterial pressure and higher end-diastolic pressure (EDP) compared with controls. End-diastolic pressure (EDP) and the left ventricular-body weight ratio (LV/BW) were reduced in the MI group after CDM. These data suggest that passive girdling of the heart provided by CDM may improve post-MI cardiac function.
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Affiliation(s)
- K De Angelis
- Laboratory of Cardiovascular Physiology, Basic and Health Sciences Institute, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
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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.
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Affiliation(s)
- A Kashem
- Division of Cardiovascular Research, Temple University, Philadelphia, Pennsylvania 19140, USA.
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Chaudhry PA, Anagnostopouls PV, Mishima T, Suzuki G, Nair H, Morita H, Sharov VG, Alferness C, Sabbah HN. Acute ventricular reduction with the acorn cardiac support device: effect on progressive left ventricular dysfunction and dilation in dogs with chronic heart failure. J Card Surg 2001; 16:118-26. [PMID: 11766829 DOI: 10.1111/j.1540-8191.2001.tb00496.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND AND AIM Surgical resection of myocardium that acutely reduces left ventricular (LV) volume in patients with advanced heart failure (HF), the so-called "Batista Operation," remains controversial. We examined the effects of acute LV reduction with the Acorn Cardiac Support Device (CSD) in dogs with HF (LV ejection fraction < 30%). METHODS HF was produced in 15 dogs by intracoronary microembolization. In nine dogs, intravenous dobutamine was administered to reduce LV end-diastolic dimension (LVEDD) by 10%-25%. While on dobutamine infusion, the CSD, a preformed knitted polyester device, was surgically placed around the ventricles, anchored to the arteriovenous (AV) groove, and tailored anteriorly to fit snugly over the ventricles. Dogs were then weaned off dobutamine. RESULTS On average, the procedure reduced LVEDD by 7 +/- 1 mm (range 5-12 mm). Of the nine dogs, two died before completion of the study and seven survived for the entire period. Six dogs did not undergo device placement and served as controls. All were followed for 3 months prior to sacrifice. In controls, LV end-diastolic volume increased after 3 months (66 +/- 5 mL vs 77 +/- 6 mL; p = 0.007), while in CSD-treated dogs (n = 7), it decreased (80 +/- 5 mL vs 60 +/- 3 mL; p = 0.002). In controls, LV ejection fraction (EF) decreased after 3 months (27 +/- 1% vs 23 +/- 1%; p = 0.001) but was unchanged in CSD-treated dogs (25 +/- 1% vs 26 +/- 1%; p = 0.66). Compared to controls, CSD-treated dogs showed improved LV diastolic dysfunction and chamber sphericity, decreased wall stress, and no functional mitral regurgitation (MR). CONCLUSION In dogs with advanced HF, acute LV reduction with the Acorn CSD prevents progressive global LV dilatation and ameliorates functional MR.
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Affiliation(s)
- P A Chaudhry
- Department of Medicine, Henry Ford Heart and Vascular Institute Henry Ford Health System, Detroit, Michigan, USA
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Chaudhry PA, Mishima T, Sharov VG, Hawkins J, Alferness C, Paone G, Sabbah HN. Passive epicardial containment prevents ventricular remodeling in heart failure. Ann Thorac Surg 2000; 70:1275-80. [PMID: 11081885 DOI: 10.1016/s0003-4975(00)01755-0] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND We examined the effects of passive containment of the cardiac ventricles with a surgically placed epicardial prosthetic wrap on indexes of left ventricular (LV) remodeling in dogs with heart failure. METHODS Heart failure (LV ejection fraction 30% to 40%) was produced in 12 dogs by intracoronary microembolization. Six dogs underwent mid-sternotomy and pericardiotomy with placement of a preformed-knitted polyester device (Acorn Cardiac Support Device [CSD], Acorn Cardiovascular, Inc, St. Paul, MN) snugly around the ventricles and anchored to the atrioventricular groove. Six dogs did not undergo surgery and served as controls. Dogs were followed for 3 months prior to sacrifice. RESULTS In controls, LV end-diastolic volume increased after 3 months (67 +/- 12 versus 83 +/- 8 ml; p = 0.04), while in CSD-treated dogs, it decreased (68 +/- 10 versus 61 +/- 10 ml; p = 0.002). CSD-containment of LV size was associated with increased LV systolic fractional area of shortening, while in controls, fractional area of shortening decreased. CSD-treated dogs also showed amelioration of myocyte hypertrophy and attenuation of interstitial fibrosis compared to controls. CONCLUSIONS In dogs with heart failure, passive epicardial containment of the ventricles with the Acorn CSD ameliorates LV remodeling and improves LV systolic function.
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Affiliation(s)
- P A Chaudhry
- Department of Medicine and Surgery, Henry Ford Heart and Vascular Institute, Henry Ford Health System, Detroit, Michigan, USA
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Blom AS, Pilla JJ, Pusca SV, Patel HJ, Dougherty L, Yuan Q, Ferrari VA, Axel L, Acker MA. Dynamic cardiomyoplasty decreases myocardial workload as assessed by tissue tagged MRI. ASAIO J 2000; 46:556-62. [PMID: 11016506 DOI: 10.1097/00002480-200009000-00009] [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: 11/26/2022] Open
Abstract
The effects of dynamic cardiomyoplasty (CMP) on global and regional left ventricular (LV) function in end-stage heart failure still remain unclear. MRI with tissue-tagging is a novel tool for studying intramyocardial motion and mechanics. To date, no studies have attempted to use MRI to simultaneously study global and regional cardiac function in a model of CMP. In this study, we used MRI with tissue-tagging and a custom designed MR compatible muscle stimulating/pressure monitoring system to assess long axis regional strain and displacement variations, as well as changes in global LV function in a model of dynamic cardiomyoplasty. Three dogs underwent rapid ventricular pacing (RVP; 215 BPM) for 10 weeks; after 4 weeks of RVP, a left posterior CMP was performed. After 1 year of dynamic muscle stimulation, the dogs were imaged in a 1.5 T clinical MR scanner. Unstimulated and muscle stimulated tagged long axis images were acquired. Quantitative 2-D regional image analysis was performed by dividing the hearts into three regions: apical, septal, and lateral. Maximum and minimum principal strains (lambda, and lambda2) and displacement (D) were determined and pooled for each region. MR LV pressure-volume (PV) loops were also generated. Muscle stimulation produced a leftward shift of the PV loops in two of the three dogs, and an increase in the peak LV pressure, while stroke volume remained unchanged. With stimulation, lambda1 decreased significantly (p<0.05) in the lateral region, whereas lambda2 increased significantly (p<0.05) in both the lateral and apical regions, indicating a decrease in strain resulting from stimulation. D only increased significantly (p<0.05) in the apical region. The decrease in strain between unassisted and assisted states indicates the heart is performing less work, while maintaining stroke volume and increasing peak LV pressure. These findings demonstrate that the muscle wrap functions as an active assist, decreasing the workload of the heart, while preserving total pump performance.
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Affiliation(s)
- A S Blom
- Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, USA
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Astra LI, Stephenson LW. Skeletal muscle as a myocardial substitute. PROCEEDINGS OF THE SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE. SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE (NEW YORK, N.Y.) 2000; 224:133-40. [PMID: 10865227 DOI: 10.1046/j.1525-1373.2000.22411.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Skeletal muscle has long been used in the field of cardiac surgery. Its use has progressed from providing myocardial reinforcement to assisting the heart by actively pumping blood. Early experiments revealed that skeletal muscle assistance could augment pressures and blood flow; however, the results were short-lived due to muscle fatigue. It was later shown that skeletal muscle can be conditioned electrically to be fatigue resistant and therefore may be useful for performing cardiac-type work. Once the details were formed of how to stimulate and manipulate the muscle to assist the heart, several configurations were devised. Cardiomyoplasty and aortomyoplasty refer to wrapping skeletal muscle around the heart or aorta, respectively. These techniques have been applied in humans; however, the effectiveness is controversial. Although most patients improve clinically, the hemodynamic parameters have not shown consistent improvements, and survival data are unknown. Skeletal muscle ventricles offer a promising alternative to both cardiomyoplasty and aortomyoplasty. These are completely separate pumping chambers constructed from skeletal muscle and connected to the circulation in a variety of configurations. Although these have not been tried in humans, the animal data appear quite convincing. The skeletal muscle ventricles have shown the greatest improvements on hemodynamic parameters with great stability over time.
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Affiliation(s)
- L I Astra
- Division of Cardiothoracic Surgery, Wayne State University School of Medicine, Detroit, Michigan 48201, USA
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Kubota H, Furuse A, Kotsuka Y, Ninomiya M, Miyaji K, Endo M, Takamoto S. Cardiac function evaluated by transesophageal echocardiography during cardiopulmonary bypass. THE JAPANESE JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY : OFFICIAL PUBLICATION OF THE JAPANESE ASSOCIATION FOR THORACIC SURGERY = NIHON KYOBU GEKA GAKKAI ZASSHI 2000; 48:261-6. [PMID: 10860277 DOI: 10.1007/bf03218137] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Abstract
OBJECTIVE To evaluate cardiac function at cardiopulmonary bypass weaning, we applied a new technique clinically to determine the approximated Emax without using a conductance catheter. METHODS Subjects were 5 patients. The left ventricular end-systolic pressure was obtained by overlaying the radial arterial pressure curve on the left ventricular pressure curve. Left ventricular end-systolic volume was assessed by a transesophageal echographic apparatus. At cardiopulmonary bypass weaning, volume loading was applied to increase left atrial pressure by a few mmHg while fixing the pump flow rate at half flow. Changes in left ventricular end-systolic volume and approximated left ventricular end-systolic pressure for total heart beat were plotted during this period, and the gradient of the regression line was taken as approximated Emax. RESULTS Approximated Emax ranged from 1.29 to 3.28 (mean 2.13 +/- 0.72), and its correlation coefficient was 0.80 +/- 0.06. CONCLUSION Our new technique is useful in evaluating cardiac function during cardiopulmonary bypass.
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Affiliation(s)
- H Kubota
- Department of Cardiothoracic Surgery, University of Tokyo, Japan
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Krako R, Mochalski M, Kuntze T, Autschbach R, Maddaj-Sterba P, Mohr FW. Experimental effects of cardiomyoplasty on stressed normal left ventricle in sheep. Eur J Cardiothorac Surg 1999; 16:506-12. [PMID: 10609900 DOI: 10.1016/s1010-7940(99)00312-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Abstract
OBJECTIVE Several basic mechanisms of cardiomyoplasty were discussed in the last years, but the definite underlying mechanism is still unknown. The aim of the present study was to determine the effects of cardiomyoplasty on pressure volume loops of the non-failed left ventricle under different myocardial working conditions. METHODS We performed cardiomyoplasty in eight female sheep after conditioning of the left latissimus dorsi muscles. To simulate different stress conditions we used myocardial stimulation up to 150/min and an increased afterload up to 140 mm Hg. The changes of left ventricular pressure and volume, aortal pressure and aortal flow were registered and analyzed. RESULTS We found a significant decrease direct cardiomyoplasty effects during simulated stress conditions with increased heart rate up to 150/min and an increased afterload up to 140 mm Hg. We have seen direct effects in the non-failing hearts at rest only. CONCLUSIONS These findings do not favor the concept of direct cardiomyoplasty-induced improvement of cardiac function under stress conditions. It seems that the conditioned and transformed skeletal muscle already under normal perfusion conditions in normal hearts is not able to generate enough force for an effective contraction under stress conditions. We conclude that the mechanism of cardiomyoplasty can not be explained by a direct effect of muscular support alone but results also from recovery of failed myocardium.
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Affiliation(s)
- R Krako
- Heart Center, University of Leipzig, Germany
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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.
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Affiliation(s)
- A T Ali
- Jewish Hospital Cardiovascular Research Center, Department of Surgery, University of Louisville School of Medicine, Kentucky, USA
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Monnet E, Orton EC. Myocardial oxygen consumption is affected by dynamic cardiomyoplasty in dogs with adriamycin-induced cardiomyopathy. J Card Surg 1998; 13:475-83. [PMID: 10543463 DOI: 10.1111/j.1540-8191.1998.tb01086.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The purpose of the study was to investigate a possible myocardial sparing effect by dynamic cardiomyoplasty. We directly measured cardiac work and myocardial oxygen consumption after dynamic cardiomyopathy in dogs with adriamycin-induced cardiomyopathy. Ten dogs with cardiomyopathy induced by 4 weekly intracoronary infusions of adriamycin were studied. Five dogs underwent right latissimus dorsi cardiomyoplasty with progressive myostimulation, and five served as controls. Right heart and coronary sinus catheterizations were performed at 0, 10, and 15 weeks. Four and two dogs, respectively, the cardiomyoplasty and the control group, survived until 15 weeks. Cardiac work was not different between the control and the cardiomyoplasty groups (p = 0.42). Myocardial oxygen consumption was less in the cardiomyoplasty group (185.70 +/- 37.22; 165.75 +/- 25.86; 161.40 +/- 54.14 J/min at 0, 10, and 15 weeks, respectively) compared to the control group (147.80 +/- 70.99; 275.00 +/- 103.24; 263.50 +/- 52.75 J/min at 0, 10, and 15 weeks, respectively, p = 0.019). Mechanical cardiac efficiency was not meaningfully different between the cardiomyoplasty group (16.08% +/- 5.39%; 20.51% +/- 5.89%; 20.67% +/- 11.98% at 0, 10, and 15 weeks, respectively) compared to the control group (15.29% +/- 8.06%; 9.40% +/- 1.22%; 13.40% +/- 2.29% at 0, 10, and 15 weeks, respectively, p = 0.093). Acute changes of the cardiosynchronization ratio (2:1, 1:1, OFF) did not affect myocardial oxygen consumption or cardiac work within the cardiomyoplasty group. Dynamic cardiomyoplasty reduced myocardial oxygen consumption in dogs with adriamycin-induced cardiomyopathy.
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Affiliation(s)
- E Monnet
- Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins 80523, USA
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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.
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Affiliation(s)
- A T Ali
- Jewish Hospital Cardiothoracic Surgical Research Institute, Department of Surgery, University of Louisville School of Medicine, KY, USA
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Niinami H, Hooper TL, Hammond RL, Ruggiero R, Lu H, Spanta AD, Pochettino A, Colson M, Stephenson LW. As originally published in 1992: Skeletal muscle ventricles in the pulmonary circulation: up to 16 weeks' experience. Updated in 1998. Ann Thorac Surg 1998; 66:977-9. [PMID: 9768978 DOI: 10.1016/s0003-4975(98)00738-3] [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: 11/30/2022]
Affiliation(s)
- H Niinami
- Department of Surgery, Wayne State University School of Medicine, Detroit, Michigan, USA
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21
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STEPHENSON LARRYW. Skeletal Muscle-Cardiac Assist: What Have We Learned? J Interv Cardiol 1998. [DOI: 10.1111/j.1540-8183.1998.tb00115.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Toyoda Y, Okada M, Kashem MA, Mukai T. Effects of cardiomyoplasty on right ventricular filling during volume loading. Ann Thorac Surg 1998; 65:1676-9. [PMID: 9647080 DOI: 10.1016/s0003-4975(98)00273-2] [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: 02/08/2023]
Abstract
BACKGROUND Although cardiomyoplasty (CMP) is thought to improve ventricular systolic function, its effects on ventricular diastolic function are not clear. Especially the effects on right ventricular diastolic filling have not been fully investigated. Because pericardial influences are more pronounced in the right ventricle than in the left ventricle, CMP with its external constraint may substantially impair right ventricular diastolic filling. METHODS Fourteen purebred adult beagles were used in this study. Seven underwent left posterior CMP, and 7 underwent a sham operation with a pericardiotomy and served as controls. Four weeks later, the hemodynamic effects of CMP were evaluated by heart catheterization before and after volume loading (central venous infusion of 10 mg/kg of 4.5% albumin solution for 5 minutes). RESULTS In the CMP group, mean right atrial pressure and right ventricular end-diastolic pressure increased significantly from 3.1 +/- 1.2 mm Hg to 6.1 +/- 2.0 mm Hg (p < 0.001) and from 4.0 +/- 1.8 mm Hg to 9.6 +/- 2.5 mm Hg (p < 0.001), respectively. Volume loading in the control group did not significantly increase either variable. Right ventricular end-diastolic volume and stroke volume did not change significantly (from 53 +/- 9.3 mL to 60 +/- 9.0 mL and from 20 +/- 2.3 mL to 21 +/- 3.2 mL, respectively) in the CMP group. In the control group, however, right ventricular end-diastolic volume and stroke volume increased significantly from 45 +/- 7.7 mL to 63 +/- 14 mL (p < 0.05) and from 18 +/- 4.3 mL to 22 +/- 4.2 mL (p < 0.05), respectively. CONCLUSIONS These results suggest that CMP may reduce right ventricular compliance and restrict right ventricular diastolic filling in response to rapid volume loading because of its external constraint.
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Affiliation(s)
- Y Toyoda
- Department of Surgery, Kobe University School of Medicine, Japan
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Kawaguchi O, Huang Y, Yuasa T, Horam CJ, Carrington RA, Biao Z, Brady PW, Murase M, Hunyor SN. Improved efficiency of energy transfer to external work in chronic cardiomyoplasty based on the pressure-volume relationship. J Thorac Cardiovasc Surg 1998; 115:1358-66. [PMID: 9628679 DOI: 10.1016/s0022-5223(98)70220-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Cardiomyoplasty is a surgical procedure to support the failing heart, in which a burst-stimulated latissimus dorsi muscle flap is transposed and wrapped around the ventricles. The effect of dynamic cardiac compression, implemented as cardiomyoplasty, on left ventricular performance remains controversial; the mechanism by which clinical symptoms are improved remains unclear. To investigate the mechanism for improvement of patients' symptoms, it is important to evaluate the effects of cardiomyoplasty on left ventricular energetics and on left ventricular systolic and diastolic function. We therefore evaluated the efficiency of energy transfer from the native pressure-volume area to external work under conditions of 1:3 skeletal muscle burst pacing in an animal model with chronic heart failure. METHODS In seven Merino-Wether sheep, cardiomyoplasty was performed after stable heart failure was induced by staged coronary embolizations (ejection fraction < 35%). Hemodynamic assessment including the assessment of the pressure-volume relationship was performed 8 weeks after cardiomyoplasty when the latissimus dorsi muscle was fully trained. Instantaneous left ventricular pressure and volume were measured with a catheter-tipped manometer and a conductance catheter during steady-state conditions and after a transient inferior vena cava occlusion. The effect of dynamic cardiac compression on left ventricular systolic function was assessed by comparing pre-assisted and assisted beats and on diastolic function by comparing assisted and post-assisted beats. RESULT The slope of the end-systolic pressure-volume relationship decreased by 30.5% +/- 27.8% (p = 0.02) during assisted beats. However, left ventricular pump performance improved by increasing stroke volume and external work by 35.9% +/- 36.0% (p = 0.03) and 9.7% +/- 6.8% (p = 0.03), respectively, resulting in a reduction of the volume intercept. As a result, the end-systolic pressure-volume relationship shifted to the left. The efficiency of energy transfer from the native pressure-volume area to the overall external work improved by 7.6% +/- 8.2% (p = 0.04). Cardiomyoplasty did not affect the time constant of left ventricular isovolumic pressure decline or the maximal rate of pressure decay, which suggested that cardiomyoplasty did not affect left ventricular relaxation. CONCLUSIONS Dynamic cardiac compression in the form of cardiomyoplasty enhanced left ventricular pump performance without interrupting left ventricular filling. The ratio of energy transfer from the native pressure-volume area to the overall external work suggests a myocardial oxygen-sparing effect of cardiomyoplasty.
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Affiliation(s)
- O Kawaguchi
- Cooperative Research Centre for Cardiac Technology, Department of Cardiothoracic Surgery, Royal North Shore Hospital, Sydney, New South Wales, Australia
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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.
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Affiliation(s)
- B B Chiang
- Department of Surgery, University of Louisville School of Medicine, Kentucky, USA
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Patel HJ, Polidori DJ, Pilla JJ, Plappert T, Kass D, St John Sutton M, Lankford EB, Acker MA. Stabilization of chronic remodeling by asynchronous cardiomyoplasty in dilated cardiomyopathy: effects of a conditioned muscle wrap. Circulation 1997; 96:3665-71. [PMID: 9396469 DOI: 10.1161/01.cir.96.10.3665] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Dynamic cardiomyoplasty is a promising new therapy for dilated cardiomyopathy. The girdling effects of a conditioned muscle wrap alone have recently been postulated to partly explain its mechanism. We investigated this effect in a canine model of chronic dilated cardiomyopathy. METHODS AND RESULTS Twenty dogs underwent rapid ventricular pacing (RVP) for 4 weeks to create a model of dilated cardiomyopathy. Seven dogs were then randomly selected to undergo subsequent cardiomyoplasty, and all dogs had 6 weeks of additional RVP. The cardiomyoplasty group also received 6 weeks of concurrent skeletal muscle stimulation consisting of single twitches delivered asynchronously at 2 Hz to transform the wrap without active assistance. All dogs were studied by pressure-volume analysis and echocardiography at baseline and after 4 and 10 weeks of pacing. Systolic indices, including ejection fraction (EF), end-systolic elastance (Ees), and preload-recruitable stroke work (PRSW) were all increased at 10 weeks in the wrap versus controls (EF, 34.0 versus 27.1, P=.008; Ees, 1.65 versus 1.26, P=.09; PRSW, 35.9 versus 25.5, P=.001). Ventricular volumes, diastolic relaxation, and left ventricular end-diastolic pressures stabilized in the cardiomyoplasty group but continued to deteriorate in controls. Both the end-systolic and end-diastolic pressure-volume relationships shifted farther rightward in controls but remained stable in the cardiomyoplasty group. CONCLUSIONS In addition to potential benefits from active systolic assistance, benefits from dynamic cardiomyoplasty appear to be partially accounted for by the presence of a conditioned muscle wrap alone. This conditioned wrap stabilizes the remodeling process of heart failure, arresting progressive deterioration of systolic and diastolic function.
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Affiliation(s)
- H J Patel
- Department of Surgery, University of Pennsylvania School of Medicine, Philadelphia 19104, USA
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Schreuder JJ, van der Veen FH, van der Velde ET, Delahaye F, Alfieri O, Jegaden O, Lorusso R, Jansen JR, Hoeksel SA, Finet G, Volterrani M, Kaulbach HG, Baan J, Wellens HJ. Left ventricular pressure-volume relationships before and after cardiomyoplasty in patients with heart failure. Circulation 1997; 96:2978-86. [PMID: 9386165 DOI: 10.1161/01.cir.96.9.2978] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND The aim of this study was to elucidate whether beneficial effects of cardiomyoplasty (CMP) in patients with dilated cardiomyopathy are the result of a decrease in existing ventricular dilatation or a prevention of further dilatation. METHODS AND RESULTS Combined micromanometer-conductance catheters were used to evaluate left ventricular pressure-volume relationships in six patients with dilated cardiomyopathy before and at 6 and 12 months after CMP. Acute changes in preload and afterload were induced by a standardized leg-tilting intervention and a bolus infusion of nitroglycerin. After CMP, end-diastolic volume (EDV) decreased from 138+/-10 to 103+/-18 mL/m2 (P<.01) at 6 months and to 83+/-17 mL/m2 (P<.01) at 12 months. End-diastolic pressure (EDP) decreased from 20.2+/-6.4 to 13.9+/-7.7 mm Hg (P<.01) at 6 months after CMP. Peak ejection rate and ejection fraction increased at 6 months after CMP from 594+/-214 to 799+/-214 mL/s (P<.05) and from 26.6+/-4.7% to 40.1+/-8.3% (P<.05), respectively. Peak dP/dt decreased at 12 months after CMP from -842+/-142 to -712+/-168 mm Hg/s (P<.05). Leg-tilting before CMP increased EDP from 20.2+/-6.4 to 25.6+/-5.2 mm Hg (P<.01), end-systolic pressure (ESP) from 118+/-17 to 122+/-17 mm Hg (P<.05), and tau from 50.8+/-2.8 to 53.8+/-2.3 ms (P<.05). Six months after CMP, leg-tilting also increased EDV from 103+/-18 to 110+/-22 mL/m2 (P<.05) and ESV from 62+/-14 to 66+/-14 mL/m2 (P<.05). Before CMP, nitroglycerin decreased EDP from 20.2+/-6.4 to 10.4+/-3.8 mm Hg (P<.01), ESP from 118+/-17 to 96+/-11 mm Hg (P<.05), ESV from 100+/-11 to 89+/-7 mL/m2 (P<.05), and tau from 50.8+/-2.8 to 44.5+/-3.7 ms (P<.05). Six months after CMP, nitroglycerin decreased EDP, ESP, and tau to similar values. CONCLUSIONS Our findings show that up to 1 year after CMP, marked decreases in left ventricular volume are present. Our measurements suggest that CMP actively reduced the dilated ventricle but did not prevent a higher EDV on an increased venous return. The latissimus dorsi muscle wrap contraction results in better synchronization of contraction and more rapid emptying of the left ventricle.
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Affiliation(s)
- J J Schreuder
- Department of Anesthesiology and Cardiology, Cardiovascular Research Institute, University Hospital Maastricht, The Netherlands.
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Aklog L, Chen FY, deGuzman BJ, Murphy MP, Smith WJ, Laurence RG, Appleyard RF, Cohn LH. Right latissimus dorsi cardiomyoplasty improves left ventricular energetics. Ann Thorac Surg 1997; 64:670-7. [PMID: 9307455 DOI: 10.1016/s0003-4975(97)00580-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND The mechanism by which cardiomyoplasty appears to enhance left ventricular (LV) function is not well understood. We applied the time-varying elastance model to study the effect of cardiomyoplasty on LV function, ventriculovascular coupling, and LV energetics in an acute canine model. METHODS Right latissimus dorsi cardiomyoplasty was performed in 5 dogs. The end-systolic pressure-volume relation was generated by using brief caval occlusions. End-systolic elastance, effective arterial elastance, stroke work, internal work, total mechanical work, and stroke work efficiency (stroke work/total mechanical work) were calculated from these pressure-volume data. Myocardial oxygen consumption and overall mechanical efficiency (stroke work/myocardial oxygen consumption) were predicted using the myocardial oxygen consumption-total mechanical work relation. RESULTS Skeletal muscle contraction significantly increased end-systolic elastance, an index of contractility. Although stroke work did not change significantly, the increase in end-systolic elastance led to a 29% decrease in total mechanical work, a 50% decrease in internal work, and an increase in stroke work efficiency from 53% to 66%. This was consistent with the observed 29% decrease in effective arterial elastance/end-systolic elastance, an indicator of ventriculovascular coupling that is related inversely to stroke work efficiency. Predicted myocardial oxygen consumption decreased by at least 22%, and predicted overall mechanical efficiency increased at a minimum from 16.1% to 18.4%. CONCLUSIONS These results support the theory that cardiomyoplasty unloads the LV by decreasing LV volumes and increasing contractility. These effects appear to improve LV energetics by decreasing total mechanical work without significantly affecting stroke work, resulting in improved stroke work efficiency. The decrease in total mechanical work strongly suggests a decrease in myocardial oxygen consumption and an increase in overall mechanical efficiency.
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Affiliation(s)
- L Aklog
- Division of Cardiac Surgery, Brigham and Women's Hospital, Boston Massachusetts 02115, USA
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Patel HJ, Lankford EB, Polidori DJ, Pilla JJ, Plappert T, St John Sutton MS, Acker MA. Dynamic cardiomyoplasty: its chronic and acute effects on the failing heart. J Thorac Cardiovasc Surg 1997; 114:169-78. [PMID: 9270632 DOI: 10.1016/s0022-5223(97)70141-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVES Dynamic cardiomyoplasty is an alternative therapy for end-stage heart failure. We investigated the mechanisms, both acute and chronic, by which a synchronously stimulated conditioned muscle wrap affects left ventricular function in a chronic canine model of dilated cardiomyopathy. METHODS Nineteen dogs underwent rapid ventricular pacing at a rate of 215 beats/min for 4 weeks to create a model of heart failure. Eight dogs were then randomly selected to undergo cardiomyoplasty, and all dogs received 6 additional weeks of rapid ventricular pacing. The cardiomyoplasty group also received a graded muscle conditioning protocol of synchronized burst stimulation to transform the muscle wrap. All dogs were studied with pressure-volume analysis and echocardiography at baseline and after 4 and 10 weeks of rapid ventricular pacing. Data in the cardiomyoplasty group were analyzed with the stimulator off, with it augmenting every beat (1:1), and with it augmenting only every other beat (1:2). RESULTS Stimulator "of" data at 10 weeks of rapid pacing demonstrated chronic effects by enhanced ventricular function (end-systolic elastance = 1.80 after myoplasty vs 1.17 for controls, p = 0.005) and a stabilization of volumes and composite end-systolic and end-diastolic pressure-volume relations in the cardiomyoplasty group when compared with controls. Myoplasty stimulation increased apparent contractility (preload recruitable stroke work = 31.3 for stimulator "of" vs 40.6 for stimulator 1:2 assisted beats [p < 0.05] and vs 45.4 for stimulator 1:1 [p < 0.05]). CONCLUSIONS Benefits from dynamic cardiomyoplasty are by at least two mechanisms: (1) the girdling effects of a conditioned muscle wrap, which halts the chronic remodeling of heart failure, and (2) active systolic assistance, which augments the apparent contractility of the failing heart.
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Affiliation(s)
- H J Patel
- Division of Cardiothoracic Surgery, University of Pennsylvania School of Medicine, Philadelphia, USA
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Kawaguchi O, Goto Y, Ohgoshi Y, Yaku H, Murase M, Suga H. Dynamic cardiac compression improves contractile efficiency of the heart. J Thorac Cardiovasc Surg 1997; 113:923-31. [PMID: 9159627 DOI: 10.1016/s0022-5223(97)70266-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The effect of dynamic cardiac compression on left ventricular contractile efficiency was assessed in terms of the pressure-volume relationship and myocardial oxygen consumption. In 11 excised cross-circulated dog hearts, the ventricle was directly compressed during systole (dynamic cardiac compression). Measurements for pressure-volume area (a measure of total mechanical energy), external work, and myocardial oxygen consumption were done before and during dynamic cardiac compression. Dynamic cardiac compression increased pressure-volume area by 28% +/- 17% (mean plus or minus the standard deviation) and external work by 24% +/- 20% (p = 0.0000185 and 0.0000212, respectively) at given end-diastolic and stroke volumes without affecting myocardial oxygen consumption. As a result, the oxygen cost of pressure-volume area, that is, the slope of the myocardial oxygen consumption-pressure-volume area relationship, significantly decreased by 16% +/- 13% (p = 0.0000135) whereas the pressure-volume area-independent myocardial oxygen consumption was unchanged. Then, contractile efficiency, that is, the reciprocal of the slope of the myocardial oxygen consumption-pressure-volume area relationship in joules significantly improved from 45% +/- 8% to 53% +/- 13% (p = 0.0000437). When the native myocardial oxygen consumption-pressure-volume area relationship was assessed by subtracting the dynamic cardiac compression pressure applied to the heart, the slope of the myocardial oxygen comsumption-pressure-volume area relationship returned to the control level. This indicates that the contractile efficiency of the native heart was not affected by dynamic cardiac compression. We conclude that dynamic cardiac compression enhances left ventricular pump function by improving the contractile efficiency of the overall heart leaving the energetics of the native heart unchanged.
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Affiliation(s)
- O Kawaguchi
- Department of Thoracic Surgery, Nagoya University School of Medicine, Japan
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Dudra J, Matsui Y, Suto Y, Yamauchi H, Gou M, Yasuda K. Effects of stimulated free latissimus dorsi muscle graft on LVEDV and LVSW: a new dynamic cardiomyoplasty technique. Artif Organs 1997; 21:306-11. [PMID: 9096803 DOI: 10.1111/j.1525-1594.1997.tb00366.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The effectiveness of dynamic cardiomyoplasty (DCMP) remains controversial. We hypothesized that effectiveness of DCMP using the latissimus dorsi muscle graft (LDMG) depends on the wrapping method. We analyzed pressure-volume relations (PVR), the left ventricular stroke work (LVSW), and the left ventricular end diastolic volume (LVEDV) changes during nonstimulation and stimulation of the LDMG to evaluate the effect of a new wrapping method of DCMP on the LVSW and the LVEDV changes. The new wrapping technique was evaluated in an acute animal experimental model. In 12 mongrel dogs, we performed continuous measurement of the dimensional and pressure dates of the left ventricle (LV) after the DCMP. The measurement was performed 15 min after wrapping during 5 periods. The duration of one measurement period was 15 s. The animals were divided into 2 groups according to the wrapping method. The heart was wrapped with the LDMG using 2 different methods. For Method 1, Carpentier's method, the heart was wrapped primarily with the distal part of the LDMG, the lateral segment. The vasculoneural pedicle of the latissimus dorsi muscle (LDM) was preserved. For Method 2, the LDM was separated, and the vasculoneural pedicle was cut. The medical sternotomy was performed. The thoracodorsal artery of LDMG was anastomosed to the right internal mammary artery, and the thoracodorsal vein was anastomosed to the right atrial appendage. The heart was wrapped primarily with the proximal part of the "free LDMG," the transverse segment. Based on the PVR loops, the changes of the LVSW and the LVEDV in both experimental groups were analyzed. The paired t-test was used for statistical analysis. Using Method 1, the LVSW and the LVEDV showed no significant changes during stimulation (stim) of the LDMG, compared with nonstimulation (nonstim) (LVSW: nonstim, 970 +/- 168 erg x 10(3); stim, 1,181 +/- 203 erg x 10(3); p = 0.126 and LVEDV: nonstim, 36.6 +/- 6.7 ml; stim, 37.2 +/- 6.8 ml; p = 0.36). Using Method 2, the LVSW was increased, and the LVEDV was decreased during stimulation of the free LDMG, compared with nonstimulation (LVSW: nonstim, 694 +/- 117 erg x 10(3); stim, 846 +/- 104 erg x 10(3); p < 0.001 and LVEDV: nonstim, 47.7 +/- 2.8 ml; stim, 46.8 +/- 2.7 ml; p < 0.001). The stimulated free LDMG wrapping of the heart seems to be a more effective wrapping method for DCMP, and it results in an increase of the LVSW and a decrease of the LVEDV, compared with the original Carpentier's method.
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Affiliation(s)
- J Dudra
- Department of Cardiovascular Surgery, Hokkaido University, Sapporo, Japan
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Thomas GA, Isoda S, Hammond RL, Lu H, Nakajima H, Nakajima HO, Greer K, Gilroy SJ, Salmons S, Stephenson LW. Pericardium-lined skeletal muscle ventricles: up to two years' in-circulation experience. Ann Thorac Surg 1996; 62:1698-706; discussion 1706-7. [PMID: 8957374 DOI: 10.1016/s0003-4975(96)00738-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND Skeletal muscle ventricles (SMVs) are autologous pumping chambers constructed from skeletal muscle. Skeletal muscle ventricular rupture and thromboembolism have complicated chronic models of this method of skeletal muscle cardiac assist. METHODS The SMVs were constructed from the latissimus dorsi muscle in 10 dogs. The inner surface of each SMV was lined with autologous pericardium harvested at the time of SMV construction. After a 3-week period of vascular delay and 6 weeks of electrical conditioning to convert the muscle to a fatigue-resistant state, SMVs were connected to the descending thoracic aorta and stimulated to contract during cardiac diastole. RESULTS Initial hemodynamics revealed that SMV contraction at 33 Hz increased diastolic pressure 24.7% (60.8 +/- 7.3 mm Hg versus 80.3 +/- 8.8 mm Hg). Skeletal muscle ventricle relaxation decreased presystolic pressure 14.4% (59.9 +/- 7.7 mm Hg versus 51.3 +/- 7.5 mm Hg) and decreased peak systolic pressure 4.1% (90.2 +/- 7.3 mm Hg versus 86.5 +/- 5.8 mm Hg). Hemodynamics were assessed at 1 to 2 weeks, then at 1, 2, 3, and 6 months, and at 6-month intervals thereafter. Hemodynamic performance remained stable for the duration of this study. After 2 years of pumping continuously in circulation, SMV contraction resulted in a 34.8% augmentation of diastolic pressure (63.6 +/- 6.6 mm Hg versus 85.3 +/- 6.4 mm Hg), a 17.2% decrease in presystolic pressure (54.7 +/- 3.73 mm Hg versus 45.3 +/- 4.1 mm Hg), and a 4.2% decrease in peak systolic pressure (95.3 +/- 10.4 mm Hg versus 91.3 +/- 12.3 mm Hg). Three dogs survived to 2 years with the SMVs in circulation. No animal showed evidence of thromboembolism during serial echocardiography or at autopsy and no SMVs ruptured. CONCLUSIONS These data demonstrate that SMVs can provide effective hemodynamic assist over an extended period without specific complications related to the SMVs.
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Affiliation(s)
- G A Thomas
- Department of Surgery, Wayne State University, Detroit, Michigan 48201, USA
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Anderson WA, Ianuzzo CD, Klabunde RE. Cardiomyoplasty: studies on goat latissimus dorsi blood flow and muscle damage following surgical dissection and chronic electrical stimulation. J Card Surg 1996; 11:237-46. [PMID: 8902637 DOI: 10.1111/j.1540-8191.1996.tb00046.x] [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: 02/02/2023]
Abstract
BACKGROUND Dynamic cardiomyoplasty has shown promise as a surgical treatment for congestive heart failure, however, skeletal muscle damage has been reported in the latissimus dorsi muscle flap. Possible etiologies for the muscle damage include surgical dissection of the latissimus dorsi muscle with interruption of collateral blood supply, as well as chronic electrical stimulation of the muscle. METHODS To investigate these possible etiologies, we conducted a series of experiments using the goat model, evaluating blood flow and muscle morphology following surgical dissection and chronic stimulation of the latissimus dorsi muscle. Four different conditions were evaluated: (1) latissimus dorsi muscle that was neither dissected nor chronically stimulated; (2) latissimus dorsi muscle that was stimulated, but not dissected; (3) latissimus dorsi muscle that was surgically dissected, but not chronically stimulated; and (4) latissimus dorsi muscle that was both surgically dissected and chronically stimulated. CONCLUSION We concluded that skeletal muscle damage resulted primarily from the surgical dissection, whereby the collateral blood supply to the latissimus dorsi muscle was interrupted and not primarily as a result of chronic electrical stimulation.
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Affiliation(s)
- W A Anderson
- Department of Surgery, Deborah Heart and Lung Center, Browns Mills, New Jersey 08015, USA
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Abstract
Dynamic cardiomyoplasty is an operation that is undergoing worldwide clinical evaluation. It had been developed to utilize the patient's own skeletal muscle to assist the failing heart. Although the clinical and quality of life benefits of cardiomyoplasty have been reported in most patients, the results of quantitative hemodynamic analyses have been less consistent. This has prompted the reevaluation of the mechanisms of dynamic cardiomyoplasty other than simple cardiac compression by the wrapped muscle. There is good evidence to suggest that the following, either together or in part, comprise some of the mechanisms of dynamic cardiomyoplasty: (1) direct systolic assist; (2) myocardial (wall stress) sparing effect; (3) remodeling/girdling effect; and (4) angiogenesis. Current concepts and potential additional mechanisms are discussed and integrated, based on a review of the literature and our own recent studies.
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Affiliation(s)
- J H Oh
- Division of Cardiothoracic Surgery, McGill University, Montreal, Canada
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Lorusso R, van der Veen F, Schreuder JJ, Bolotin G, Kaulbach HG, Frietman R, Habets J, van der Nagel T, Wellens HJ. Hemodynamic effects in acute cardiomyoplasty of different wrapped muscle activation times as measured by pressure-volume relations. J Card Surg 1996; 11:217-25. [PMID: 8889882 DOI: 10.1111/j.1540-8191.1996.tb00042.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Correct timing of mechanical interaction between wrapped latissimus dorsi muscle (LDM) and the heart during cardiac systole has been poorly understood and remains a controversial issue. Therefore, left ventricular pressure-volume relations were analyzed in acute cardiomyoplasty while changing the synchronization delays. METHODS Effects of different delays between the sensed cardiac R wave and wrapped muscle contraction were studied in goats submitted to acute left cardiomyoplasty. Conductance and micromanometer catheters were used to evaluate hemodynamics. Systolic contribution of the wrapped muscle was studied in preassisted and assisted beats, whereas diastolic effects were studied in assisted and postassisted beats. RESULTS At best settings, cardiomyoplasty resulted in a significant (p < 0.05) increase in left ventricular ejection fraction (from 42.2 +/- 9.2 to 56.7% +/- 13%), in stroke work (from 2769 +/- 1140 to 4271 +/- 1717 gm/m2), in dP/dt (from 1185 +/- 342 to 1510 +/- 285 mmHg/sec), in end-systolic pressure (from 93.5 +/- 22.5 mmHg to 97.3 +/- 22.3 mmHg), and in peak ejection rate (from 282 +/- 64 to 533 +/- 241 mL/sec). Stroke volume showed a mean increase of 35% (from 42.2 +/- 9.9 mL to 56.9 +/- 20.1 mL) during assisted beats. Diastolic function was not substantially impaired at optimal stimulation delay. Incorrect timing of LD contraction resulted in suboptimal improvement or no change in comparison with unassisted hemodynamics. CONCLUSIONS Our study documents support of cardiac performance by LDM. Incorrect timing of heart/wrapped muscle interaction led to suboptimal hemodynamic results. Muscle contraction timing is an important factor in cardiomyoplasty outcome.
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Affiliation(s)
- R Lorusso
- Department of Cardiology, Academic Hospital Maastricht, The Netherlands
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Chen FY, Aklog L, deGuzman BJ, Laurence RG, Couper GS, Appleyard RF, Cohn LH, McMahon TA. New technique measures decreased transmural myocardial pressure in cardiomyoplasty. Ann Thorac Surg 1995; 60:1678-82. [PMID: 8787462 DOI: 10.1016/0003-4975(95)00713-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND We introduce the use of a fluid-filled balloon, interposed between myocardium and latissimus dorsi (LD), as a new technique to measure transmural myocardial pressure in an acute goat model of dynamic cardiomyoplasty. METHODS A half-ellipsoidal balloon, composed of polychloryl vinyl layers, was sutured to the atrioventricular groove in 5 goats, thereby completely enveloping both ventricles. Left LD dynamic cardiomyoplasty was then performed, anchoring the LD to the felt sewing skirt of the balloon so that the LD completely covered the balloon. Left ventricular pressure and balloon pressure were measured with the stimulator in the 1:2 mode as balloon volume was varied. RESULTS Average transmural myocardial pressure, defined as left ventricular pressure minus balloon pressure, decreased from 34.4 mm Hg to 15.6 mm Hg during stimulator-on beats (p < 0.05). CONCLUSION These results support the conclusion that dynamic cardiomyoplasty unloads the left ventricle by decreasing wall stress. Furthermore, transmural myocardial pressure decreased more when balloon volume was increased, implying that the LD sarcomere length has an effect on wall stress. A balloon may therefore allow optimization of LD sarcomere length and thus assisted cardiac performance.
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Affiliation(s)
- F Y Chen
- Division of Cardiac Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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Hagège AA, Desnos M, Fernandez F, Besse B, Mirochnik N, Castaldo M, Chachques JC, Carpentier A, Guérot C. Clinical study of the effects of latissimus dorsi muscle flap stimulation after cardiomyoplasty. Circulation 1995; 92:II210-5. [PMID: 7586411 DOI: 10.1161/01.cir.92.9.210] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND Beneficial hemodynamic effects after dynamic cardiomyoplasty have been inconsistently demonstrated, and the effects seen may be due to the wrap itself, to flap stimulation, or both. The aim of this study was to determine whether flap stimulation per se acts as a systolic active process after cardiomyoplasty. METHODS AND RESULTS Catheterizations were performed in 13 patients 14.4 +/- 7 months after cardiomyoplasty. New York Heart Association functional class decreased from 3.3 to 2.1 after the procedure (P = .0005). Hemodynamic evaluations were first performed with the stimulator on in the 2:1 mode and then after the stimulator had been off for at least 24 hours. Left ventricular (LV) ejection fraction increased from 25.1 +/- 6% before surgery to 28.2 +/- 6.7% with the stimulator on after cardiomyoplasty (P = .04). When stimulation was stopped, there was no change (P > .05) in indexes of systolic or diastolic LV function (peak systolic LV pressure, LV ejection fraction, peak positive dP/dt, peak negative dP/dt, or tau). Pulmonary capillary wedge pressure and cardiac index were unchanged when stimulated and nonstimulated settings were compared (P > .05). However, a remarkable heterogeneity of individual responses was observed. Ejection fraction and cardiac index decreased with the stimulator off in 3 patients, but peak positive dP/dt decreased in 6 patients; diastolic function deteriorated in 2 patients, but a slight improvement was noted in 3 patients. Cardiothoracic ratio, echocardiographic LV end-diastolic dimension, and fractional shortening remained unchanged between immediate (< 1 month) and long-term (36.7 +/- 25.9 months) postoperative evaluations. CONCLUSIONS In the majority of our patients, there was no short-term hemodynamic benefit of flap stimulation; therefore, we conclude that the efficacy of cardiomyoplasty may be a consequence of a passive "girdling effect," which limits the progression of ventricular enlargement and further deterioration of ejection fraction.
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Affiliation(s)
- A A Hagège
- Department of Cardiology, Boucicaut Hospital, Paris, France
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37
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Bocchi EA, Guimarães GV, Moreira LF, Bacal F, de Moraes AV, Barreto AC, Wajngarten M, Bellotti G, Stolf N, Jatene A. Peak oxygen consumption and resting left ventricular ejection fraction changes after cardiomyoplasty at 6-month follow-up. Circulation 1995; 92:II216-22. [PMID: 7586412 DOI: 10.1161/01.cir.92.9.216] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND The effects of cardiomyoplasty on cardiopulmonary exercise test characteristics are not fully known. METHODS AND RESULTS We determined in 19 patients who underwent cardiomyoplasty for treatment of refractory heart failure (New York Heart Association [NYHA] functional class III) before (pre) and at 6-month follow-up (post) maximum oxygen consumption (peak VO2), NYHA functional class, and resting left ventricular ejection fraction (LVEF) (MUGA). We analyzed the results according to pre peak VO2 < or > 14 mL/kg per minute and the correlation between the changes in absolute values of LVEF and peak VO2. Pre- and post-peak VO2 values were 15.9 +/- 4.4 and 18.6 +/- 6.4 mL/kg per minute, respectively (P = .059). In the subgroup with pre-peak VO2 < 14 mL/kg per minute, the peak VO2 increased from 11.1 +/- 1.9 to 16.4 +/- 6.2 mL/kg per minute (P = .02). The subgroup with peak VO2 > 14 mL/kg per minute showed pre- and post-peak VO2 of 19.2 +/- 2.6 and of 20.1 +/- 7 mL/kg per minute, respectively (P = .06). The pre-total exercise time of the entire group increased from 688.4 +/- 222.1 to 833.7 +/- 241.6 seconds (P < .04). For the subgroup with preoperative peak VO2 < 14 mL/kg per minute, exercise time improved from 585 +/- 76.9 to 825 +/- 186.3 seconds (P < .01). In the subgroup with preoperative VO2 > 14 mL/kg per minute, the preexercise and postexercise time was 763.6 +/- 264.4 and 840 +/- 282 seconds, respectively (P = .4). Pre-LVEF increased from 20.6 +/- 3.3% to 24.2 +/- 7.8% at 6 months of follow-up (P = .02). At 6 months of follow-up, 9 patients were in NYHA functional class I and 10 were in class II. There was no correlation between LVEF values and absolute values of peak VO2 before (r = .123, P = .6) and after (r = .27, P = .2) cardiomyoplasty. A weak correlation was observed between the changes in absolute values of peak VO2 and LVEF from the preoperative to the postoperative period (r = .48, P = .048). CONCLUSIONS Cardiomyoplasty is a useful method for improving NYHA functional class and LVEF in patients with heart failure. Peak VO2 < 14 mL/kg per minute before cardiomyoplasty may be a selection criterion with which to determine improved exercise capacity after surgery. The effects of cardiomyoplasty on LVEF appear to be partially associated with maximum exercise capacity changes.
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Affiliation(s)
- E A Bocchi
- Heart Institute, São Paulo (Brazil), University Medical School
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Helou J, Misawa Y, Stewart JA, Colson M, Chiu RC. Optimizing "delay period" for burst stimulation in dynamic cardiomyoplasty. Ann Thorac Surg 1995; 59:74-7. [PMID: 7818363 DOI: 10.1016/0003-4975(94)00753-t] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Hemodynamic evidence of systolic assist after dynamic cardiomyoplasty remains inconsistent. One of the relevant factors may be how the burst stimulator is programmed. In 3 patients who underwent cardiomyoplasty for idiopathic dilated cardiomyopathy, we examined the modes used to determine the delay period between the R-wave sensing and the onset of burst stimulation during cardiac systole. These modes include the fixed time mode, the valve-synchronized mode, and the flow-optimized mode. The rationale for choosing these modes and the benefits conferred by each are discussed.
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Affiliation(s)
- J Helou
- Division of Cardiovascular and Thoracic Surgery, McGill University, Montreal, Quebec, Canada
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Affiliation(s)
- R M el Oakley
- Department of Cardiac Surgery, Royal Brompton National Heart and Lung Hospitals, London, UK
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