Dynamic cardiomyoplasty: clinical follow-up at 12 years.

OBJECTIVE: The purpose of this study is to evaluate the long-term outcome of dynamic cardiomyoplasty. This surgical technique was conceived to assist the failing heart. The many proposed mechanisms of action of cardiomyoplasty are: (1) systolic assist; (2) limitation of ventricular dilation; (3) reduction of ventricular wall stress (sparing effect); (4) ventricular remodeling with an active girdling effect; (5) angiogenesis; and (6) a neurohumoral effect. METHODS: We investigated 95 patients in our hospital undergoing this procedure due to severe chronic heart failure, refractory to optimal medical treatment. Patients had a mean age of 51 +/- 12 years. The etiology of heart failure was ischemic 55%, idiopathic 34%, ventricular tumor 6%, and other 5%. The mean follow-up was 44 months. RESULTS: The mean New York Heart Association (NYHA) functional class improved postoperatively from 3.2 to 1.8. Average radioisotopic left ventricular (LV) ejection fraction increased from 17 +/- 5 to 27 +/- 4% (P < 0.05). Stroke volume index increased from 32 +/- 7 to 43 +/- 8 ml/beat per m2 (P < 0.05). The heart size remained stable over the long term. Following cardiomyoplasty, the number of hospitalizations due to congestive heart failure was reduced to 0.4 hospitalizations/patient per year (preoperative: 2.5, P < 0.05). Computed tomography scans showed at long term a preserved latissimus dorsi muscle structure in 84% of patients. Survival probability at 7 years is 54%. Six patients underwent heart transplant after cardiomyoplasty (mean delay: 25 months), due to the natural evolution of their underlying heart disease. There were no specific technical difficulties. CONCLUSIONS: Clinically, this procedure reverses heart failure, improves functional class and ameliorates quality of life. The latissimus dorsi muscle histological structure is maintained at long-term, when postoperative electrostimulation is performed, avoiding excessive stimulation. Cardiomyoplasty may delay or prevent the progression of heart failure and the indication of cardiac transplantation.

Study of muscular and ventricular function in dynamic cardiomyoplasty: a ten-year follow-up.

BACKGROUND: The basic physiologic principle underlying cardiomyoplasty is long-term electrostimulation of a latissimus dorsi muscle (LDM) wrapped around the heart to obtain a phasic activity that could be integrated with ventricular kinetics. The aim of cardiomyoplasty is to prolong survival and to improve the quality of life of patients with severe chronic and irreversible myocardial failure by improving systolic contraction and correcting diastolic dysfunction. METHODS: To evaluate the long-term outcome of cardiomyoplasty, we investigated 82 patients electively undergoing this procedure in-our hospital. All patients had severe chronic heart failure that did not respond to optimal medical treatment. Patients had a mean age of 50 +/- 12 years (84% males). The cause of heart failure was ischemic (55%), idiopathic cardiomyopathy (34%), ventricular tumor (6%), and other (5%). The mean follow-up was 4.3 years. RESULTS: The mean New York Heart Association functional class improved after operation from 3.2 to 1.8. Average radioisotopic left ventricular ejection fraction increased from 17% +/- 6% to 28% +/- 3% (p < 0.05). Stroke volume index increased from 35 +/- 9 to 46 +/- 8 ml/beat/m2 (p < 0.05). The heart size remained stable at long term (evaluated by echo and computed tomography scanning). After cardiomyoplasty the number of successive hospitalizations resulting from congestive heart failure was reduced to 0.4 hospitalizations/patient/year (before operation 2.5, p < 0.05). Computed tomography scans showed at long-term a preserved LDM structure in 82% of patients who underwent operation. Survival probability at 7 years was 54% for the totality of patients, and 66% for patients who underwent operation in New York Heart Association functional class 3. Five patients underwent heart transplantation after cardiomyoplasty (mean delay 29 months), principally as a result of the natural evolution of their underlying heart disease, without major technical difficulties. CONCLUSIONS: Our 10-year clinical experience demonstrates that cardiomyoplasty increases ejection fraction, improves functional class, and ameliorates quality of life. Ventricular volumes and diameters remain stable long term. LDM structure is maintained long term if electrostimulation is performed avoiding excessive myostimulation. Patient selection is the most important determinant for early and late outcome. Late death in patients undergoing cardiomyoplasty is principally due to sudden death. Our future aim is to incorporate a cardioverter-defibrillator in the cardiomyostimulator, thus improving long-term results. Cardiomyoplasty may delay or prevent end-stage heart failure and the need for heart transplantation.

Progressive latissimus dorsi muscle denervation for free-flap dynamic cardiomyoplasty.

BACKGROUND: The creation of free muscle grafts for surgical myoplasty is limited by the dependence of muscle on its original nerve supply. The aim of this study was to develop a model of gradual denervation of a large skeletal muscle (latissimus dorsi) and evaluate the possibility that atrophic degeneration and loss of function would be reduced using progressive nerve compression instead of surgical division of the nerve. The effects of chronic stimulation prior to, and after, denervation were also evaluated. METHODS: Electrodes connected to a myostimulator were implanted on 24 latissimus dorsi muscles of 12 goats. Denervation of these muscles was achieved either by sectioning of the nerve by progressive compression using ameroid rings placed around the nerve. Electrostimulation of the muscle started either 5 weeks before (prestimulation), or immediately after the denervation. RESULTS: The model of gradual nerve compression was successfully created and did have less atrophy and loss of function at mid-term when compared with nerve division. Chronic electrostimulation of the muscle after nerve division had a beneficial effect on function and on the atrophic process. Chronic electrostimulation in our model of gradual nerve compression did not mirror these beneficial results. Detrimental results were observed in groups in which chronic electrostimulation was applied prior to nerve division or constriction.

[Cardiomyoplasty as treatment of chronic severe cardiac failure]. / Cardiomioplastia como tratamiento de la insuficiencia cardíaca crónica severa.

INTRODUCTION AND OBJECTIVES: Cardiac assistance from skeletal muscle is now emerging as an alternative to transplant surgery. The principle of cardiomyoplasty is chronic electrostimulation of the latissimus muscle flap wrapped around the heart to obtain a phasic activity which can be integrated to ventricular kinetics. Cardiomyoplasty is appropriate for patients with cardiac insufficiency refractory to optimal medical treatment. This includes cardiac failure of ischemic and non-obstructive cardiomyopathies. Worldwide clinical experience with this technique involves more than 500 cases. MATERIAL AND METHODS: The Broussais Hospital clinical experience involves 80 patients, operated between 1985 and 1995. All of them were closely followed in the postoperative period. RESULTS: Recent basic and clinical data have shown that cardiomyoplasty effects on ventricular performance are due to: 1) augmentation of pump function: 2) limitation of cardiac dilatation; 3) reduction of ventricular wall stress, and 4) reverse remodeling of the left ventricular geometry. Remarkably, continuous fatigue free contraction of the latissimus dorsi muscle at the frequency of the heart has been obtained for periods exceeding 10 years in humans. Five patients underwent cardiac transplantation due to refractory heart failure. CONCLUSIONS: Clinical experience has demonstrated that cardiomyoplasty is an efficient technique to assist patients with severe refractory cardiac failure. In the great majority of cases it reverses the heart failure and increases life expectancy. Moreover, the functional class and the quality-of-life are significantly improved. Cardiomyoplasty does not preclude the use of future orthotopic heart transplantation.

Association of latissimus dorsi muscle expansion with electrostimulation before cardiomyoplasty.

BACKGROUND: The principle of cardiomyoplasty is chronic electrostimulation of the latissimus dorsi muscle (LDM) flap wrapped around the heart to obtain a phasic activity that can be integrated to ventricular kinetics. In clinical cardiomyoplasty procedures, a complete wrap of both ventricles by the LDM cannot always be obtained in cases of extremely dilated hearts. This is due to the limited LDM length available for wrapping. In most of these cases, benefits of cardiomyoplasty are very limited. We have investigated the feasibility of progressive LDM expansion associated with electrostimulation. The aim was to increase the muscle area before cardiomyoplasty, while preserving the electrophysiologic characteristics of muscle fibers. METHODS: In 5 goats, a silicone LDM expander with two incorporated muscular pacing electrodes was inserted deep into the LDM through a paravertebral incision along the posterior edge of the muscle. The pacing leads were connected to a myostimulator implanted in a subcutaneous pocket. The expander was progressively inflated over 8 weeks, up to 500 mL. Simultaneously the LDM was electrostimulated. RESULTS: At 2 months planimetric studies demonstrated an increase of the LDM surface from 175 +/- 12 to 229 +/- 17 cm2 (+31% +/- 4%; p < 0.05). The expanded LDM showed preserved electrophysiologic characteristics. The analysis of biopsy samples revealed histologic integrity of muscle fibers and preservation of their mean diameter. CONCLUSIONS: Potential benefits of this procedure are (1) increase of muscle surface, (2) training of muscular fibers and preservation of muscular tone, and (3) division of the distal vascular supply at implantation, which may potentiate vascularization from the LDM main pedicle. An LDM expansion could be considered before cardiomyoplasty in cases of significant heart dilatation. This device was successfully implanted in 2 patients, 2 months before cardiomyoplasty. Cardiomyoplasties were performed without difficulty, and a complete biventricular wrap was obtained in both patients in spite of massive cardiomegaly.

Aortomyoplasty counterpulsation: experimental results and early clinical experience.

BACKGROUND: Presently the only clinical method of skeletal muscle augmentation of the heart is achieved by wrapping muscle around the cardiac ventricles and then stimulating the muscle to contract synchronously with cardiac systole. Intraaortic balloon counterpulsation provides diastolic counterpulsation in the short-term with the known benefits of increasing diastolic pressure and reducing ventricular afterload. Using protocols already in existence for dynamic cardiomyoplasty we have investigated the long-term use of extraaortic skeletal muscle-powered counterpulsation. METHODS: In five alpine goats the right latissimus dorsi muscle (LDM) was used to achieve a wrap around the ascending aorta, which had been augmented with an elliptic pericardial patch. Electrostimulation protocols were commenced after 2 weeks and continued for 12 to 24 months. At this time baseline hemodynamic measurements were made with and without stimulation of the LDM. Acute cardiac depression was induced and further measurements were made, again with and without stimulation of the LDM. RESULTS: Results in the basal state demonstrated improvement in all parameters with stimulation and a 23% increase of the subendocardial viability index. After induction of cardiac depression there was a 52% increase in cardiac output, 39% decrease in systemic vascular resistance, and 27% increase in subendocardial viability index. Histologic studies demonstrated tight adhesion between the aortic wall and the LDM, no dilatation of the aortic wall, and no deleterious effects in the aortic wall of the chronic intermittent constriction. Histochemical staining demonstrated transformation of the muscle fibers of the LDM flap into type 1 oxidative muscle fibers. CONCLUSIONS: In conclusion, our present study demonstrates that in this animal model aortomyoplasty produces a chronic counterpulsation with preservation of aortic architecture. With induction of heart failure aortomyoplasty provided an effective means of cardiac assistance. The use of the ascending aorta to achieve diastolic counterpulsation may be an efficient use of skeletal muscle energy to augment the heart in selected clinical cases. Early clinical experience is described in this article.

Clinical study of the effects of latissimus dorsi muscle flap stimulation after cardiomyoplasty.

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.

Long-term effects of dynamic aortomyoplasty.

Aortomyoplasty consists of wrapping the latissimus dorsi muscle (LDM) around the ascending aorta and electrostimulating it during diastole. The ascending aorta will act as an ectopic neo-ventricle compressed during diastole, thus reproducing the effects of long-term diastolic counterpulsation. In 5 goats, the right LDM was transferred to the thoracic cavity after removal of the second rib. The ascending aorta was enlarged by a pericardial patch and wrapped with the LDM. Postoperative electrostimulation was delivered in a counterpulsating manner. Hemodynamic studies were performed at 12 and 24 months postoperatively. Percent increase in the subendocardial viability index (diastolic pressure-time index/systolic tension-time index) was calculated using unassisted and assisted cardiac cycles with the stimulator off versus the stimulator on at a 1:1 ratio in the basal state and after acute heart failure was induced by the administration of high doses of propranolol hydrochloride. Diastolic counterpulsation of the ascending aorta resulted in significant improvement in the subendocardial viability index long term, both in basal state conditions and after induced cardiac failure. During heart failure, aortomyoplasty increased the cardiac output and decreased systemic vascular resistance. Histopathologic studies up to 24 months showed preservation of the histologic structure of the aortic wall and no evidence of thromboembolism. Tight adhesions developed between the aortic wall (including the pericardial patch) and the LDM. The diameters of the enlarged aortas showed no significant differences compared with diameters immediately postoperatively. In conclusion, aortomyoplasty produces chronic diastolic augmentation with preservation of aortic structure. After induction of heart failure, aortomyoplasty offers efficient circulatory support.

[Circulatory assistance through cardiomyoplasty and aortomyoplasty. Experience and first clinical results]. / Assistance circulatoire par cardiomyoplastie et aortomyoplastie. Expérience et premiers résultats cliniques.

The finding that skeletal muscles can be made resistant to fatigue by progressive electrical stimulation has been used as a means of providing circulatory support in cardiac surgery. The first application of this discovery was dynamic cardiomyoplasty, performed for the first time in man in 1985 at the Broussais Hospital, Paris. The latissimus dorsi muscle is transposed into the thorax, then attached around the heart and finally stimulated synchronously with the ventricular systole. So far, more than 200 patients in the whole world (including 57 at the Broussais Hospital) have undergone this operation with results that are increasingly encouraging. In these cases the muscle is used to reinforce or replace the left or right ventricle, but other applications are being studied, such as double cardiomyoplasty (left latissimus dorsi and right pectoralis major muscles), cardiomyoplasty of the right atrium and aortomyoplasty which produces aortic counterpulsation. The development of these techniques underlines the ever growing interest raised by this type of autologous circulatory support.

Dynamic cardiomyoplasty for long-term cardiac assist.

The principle of cardiomyoplasty is long-term electrostimulation of a latissimus dorsi muscle (LDM) wrapped around the failing heart. Technically, this procedure consists of placing the left LDM flap around the heart via a window created by partial resection of the 2nd or 3rd rib, and subsequent muscle electrostimulation in synchrony with ventricular systole. The aim of cardiomyoplasty is to support ventricular function in ischemic or dilated cardiomyopathies, or to partially replace the ventricular myocardium after large aneurysm or tumor resections. Our clinical experience at Broussais Hospital involves 44 patients. The functional class and quality of life improved after cardiomyoplasty. Improvement of the ventricular performance and limitation of cardiac dilatation were demonstrated over the long-term. The actuarial survival at 6 years was 71%. Risk factors influencing perioperative mortality were: age > 65 years, associated surgical procedures, pulmonary vascular hypertension, and patients hemodynamically unstable or on inotropic drug support. Preoperative risk factors influencing the long-term mortality were: permanent NYHA functional class 4, cardiothoracic ratio > 0.60, LV ejection fraction < 15%, bi-ventricular heart failure, and atrial fibrillation. Cardiomyoplasty does not preclude the use of future orthotopic heart transplantation.

Patient management and clinical follow-up after cardiomyoplasty.

The purpose of this article is to provide an overview of patient management following latissimus dorsi cardiomyoplasty, based on clinical experience with 34 patients operated on between 1985 and 1990. Postoperative patient care includes: (1) clinical follow-up, (2) electrostimulation management, and (3) management of complications. The efficacy of cardiomyoplasty is principally evaluated by the quality-of-life before and after cardiomyoplasty (New York Heart Association [NYHA] functional class), number of rehospitalizations due to congestive heart failure, amount of pharmacological support, exercise capacity, postoperative reintegration and adaptation to working life, and late survival.

Long-term efficacy of dynamic cardiomyoplasty. Clinical, ultrasonic and haemodynamic evidence in one case.

We report one case of successful cardiomyoplasty in a 21-year-old male and its beneficial effects as assessed by clinical examination, Doppler echocardiography, phonocardiography, haemodynamic and angiographic evaluation at 1 year. Long-term efficacy of this procedure on left ventricular function was confirmed by these techniques.

Cardiac assistance by atrial or ventricular cardiomyoplasty.

Dynamic cardiomyoplasty was conceived to enhance cardiac performance by assisting myocardial contraction. Technically, this procedure consists of placing a pedicled latissimus dorsi muscle flap around the heart and subsequent muscle electrostimulation in synchrony with ventricular systole. Three types of dynamic cardiomyoplasty can be considered. (1) Atrial or ventricular reinforcement is accomplished by wrapping the latissimus dorsi muscle flap around the heart to support hypokinetic or akinetic areas secondary to congenital or acquired diseases. The atrial reinforcement may be performed to improve atrial output after Fontan-type procedures. (2) Ventricular substitution is performed to replace a portion of the ventricular wall. Autologous pericardium is used to create a neoendocardium and facilitate hemostatic closure of the ventricle. The pedicled latissimus dorsi is then secured to replace the resected myocardium. (3) The two previous techniques of ventricular substitution and reinforcement are combined. This reconstructive procedure, which normalizes the ventricular geometrical shape, is particularly useful after extended cardiac resections, such as is done in treatment of large ventricular aneurysms, cardiac tumors, or echinococcal cyst formations. At present, improvement in ventricular function has been obtained in 12 patients at our institution. Preoperative severe cardiac dysfunction was present in all of these patients (New York Heart Association functional class III or IV). Postoperative echocardiography, multigated acquisition scan, and hemodynamic studies demonstrate an improvement in ventricular function and no impairment of ventricular compliance by the muscle flap. After a mean follow-up period of 18 months, all patients are in functional class I or II. We believe that dynamic cardiomyoplasty prolongs and improves the quality of life of patients suffering from severe chronic and irreversible myocardial dysfunction by improving ventricular contraction and limiting cardiac dilatation.

[Cardiomyoplasty. Experimental bases, operative technic, indications]. / Cardiomyoplastie. Bases expérimentales, technique opératoire, indications.

Dynamic cardiomyoplasty aims at restoring ventricular contractility by means of a skeletal muscle sutured around the heart. It consists of transferring a latissimus dorsi muscle flap onto the heart through a window created in the thoracic wall by partial resection of the second rib. The skeletal muscle may be used to reinforce the ventricular systole in ischemic or dilated cardiomyopathy, or to replace the myocardium after resection of a large aneurysm or an extensive tumour. The electronic pacing material includes an implantable cardiomyostimulator, muscle stimulating electrodes and R wave detecting electrodes. Muscular pacing begins 2 weeks after the operation, this being the time required for adhesions to be formed between the heart and the muscle. A progressive and sequential electrostimulation procedure results in the transformation of glycolytic muscle fibres that are fatigue-sensitive into fatigue-resistant oxidative fibres. The purpose of this biomechanical cardiac assistance system, where cardiac surgery is combined with plastic surgery and biomedical engineering, is to prolong life and improve its quality in patients with severe heart failure.

Experimental cardioplasty using the latissimus dorsi muscle flap.

This study was undertaken to examine the possibility of using the latissimus dorsi muscular flap, divided in two parts thus covering the surfaces of the heart, and inserting it into the thoracic cavity by means of a segmental resection of the second rib. After cadaver case studies, 15 operations were performed on 5 Beagle dogs. The first group of 5 operations consisted of a latissimus dorsi flap graft over the heart. The second group and third group of operations (3 and 6 months later) consisted of reoperating for muscular and cardiac biopsies and electrical stimulation tests on the heart-muscle complex. The latissimus dorsi flap provided a sizable mass of contractile tissue. The haemodynamic studies showed no compressive or constrictive phenomenon of the muscle on the heart and revealed the preservation of an appropriate cardiac output for short intervals of time (2 hours), through phasic electrostimulation of the flap. The histopathological studies showed conserved muscular structure. The technical feasibility, histological adaptability and electrophysiological properties of this muscular flap makes it appropriate to develop a functional stimulation programme and perhaps adequate for the treatment of dysplasic, ischemic, tumoral and other acquired or congenital myocardial diseases.

[Transformation of skeletal muscle by progressive sequential stimulation with a view toward its use as a myocardial substitute]. / Transformation d'un muscle squelettique par stimulation séquentielle progressive en vue de son utilisation comme substitut myocardique.

Progressive sequential stimulation of a skeletal muscle using trains of 30 Hz impulses with increasing frequencies from 20/min. to 80/min. within 3 months, allowed us to obtain in goats a transformation of the fast twitch glycolytic muscular fibers into fatigue resistant slow twitch oxidative muscular fibers. The conditioned muscle can be used in the treatment of various myocardial lesions or to reinforce cardiac contractility in severe cardiac insufficiencies. The first clinical case successfully operated upon is reported.