Special problems in use of the total artificial heart as a bridge to transplantation.
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Adolescent↗
Biomedical subjects
E Solis
Publications and source records attributed to E Solis.
Doppler echocardiography: an excellent noninvasive method for the detection of acute cardiac allograft rejection.
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Acute Disease↗
Hemodynamic characteristics of the Jarvik-7 total artificial heart.
To identify the optimal means of artificial circulation, driving controls and resultant hemodynamics were correlated with clinical outcomes in 37 Jarvik-7 recipients up to 72 hours after implantation. When patients with subsequent transplantation (n = 16) were compared with those who died on the Jarvik-7 heart (n = 21), there were no significant differences in total artificial heart driving mode such as frequency, ventricular driving pressures, systolic-diastolic ratio, or vacuum use, nor were there any differences in the hemodynamics achieved, such as device output (cardiac output) or atrial filling pressures, throughout the observation. However, improvements of other organ functions, especially kidney and liver, were remarkable in that transplant patients immediately experienced increased urine output and reversal of secondary organ dysfunction. The nontransplant group failed to diurese and continued to deteriorate despite similar hemodynamics. When a smaller model of the Jarvik-7 (volume of 70 ml, n = 18) was compared with the standard model (volume of 100 ml, n = 19), again there were no significant differences except that ventricular stroke volume was consistently less for the 70-ml model. Because of a slightly higher heart rate in the smaller model, device output did not differ between recipients of the two types. The results suggest that once successfully implanted, the Jarvik-7 provides adequate perfusion without associated mortality from circulatory failure, regardless of the size of the ventricle. Recovery from other organ failure appears to be independent of postimplant hemodynamics, a phenomenon that suggests the importance of preimplant status and patient selection.
Adult↗
Clinical application and patient selection in the use of a total artificial heart as a bridge for transplantation.
Between April 1986 and July 1987, 21 patients underwent orthotopic implantation of a total artificial heart (Jarvik 7) at La Pitié Hospital. There were 18 men and 3 women with a mean age of 37.3 +/- 11.4 years. The device implanted was the 70 ml version in 10 patients and the 100 ml version in 11 patients. In the results, three variables were analysed: age, acute myocardial decompensation or chronic myocardial failure, and aetiology of the 21 patients treated. 10 (47.6%) had adequate support and were successfully transplanted. Eleven patients (52.4%) died during circulatory support. The main causes of death were sepsis and multiple organ failure. In only one patient was a mismatch between the heart and chest cavity present. There was no clinical evidence of thromboembolic complications. Patients of 40 years of age and less have an 80% chance of being successfully transplanted in comparison with a 25% success rate in older patients. Patients that developed sudden cardiac decompensation have a 75% success rate for transplantation in comparison with 44.4% success rate in patients with a chronic illness. Early implantation of the device, before the development of irreversible damage in other organs, is recommended in younger patients with acute or chronic disease and in older patients with acute myocardial failure. The use of this device is contraindicated in immunosuppressed patients due to the high risk of infection.
Adult↗
Calcified aortic stenosis: operative risk.
Surgery of the aortic valve due to calcified aortic stenosis has been a well known procedure for many years. Continuous clinical improvement after isolated aortic valve replacement can be documented in the majority of patients followed up for several years. Surgery of this type in association with other procedures (coronary artery bypass, mitral valve replacement, etc.) has become more and more common. For this reason we have analysed the operative risk of a group of patients with calcified aortic stenosis that were operated on at La Pitié Hospital from 1980 to 1984.
Age Factors↗
Left ventricular preparation with an extrathoracically adjustable balloon occluder.
We developed a hydraulic occluder that could be adjusted percutaneously through a subcutaneous reservoir. Because of the potentially high pressures that may occur in preparing patients with transposition of the great vessels for an atrial switch procedure, the band on that hydrauler was modified to withstand arterial pressure and was subjected to studies involving banding of the aorta. Data indicate the suitability of this hydraulic occluder to withstand and maintain pressure in the systemic circulation.
Animals↗
Current problems in cardiac transplantation.
In conclusion, after almost 20 years of clinical application and due to much progress during that time by the pioneers of the method, cardiac transplantation is now a safe and reliable treatment for patients in intractable cardiac failure untreatable by other medical or surgical means. Several challenging problems remain to be resolved by the many active and excellent centers now engaged in this promising field.
Heart Transplantation↗
Superoxide generation during cardiopulmonary bypass: is there a role for vitamin E?
The cytotoxic metabolites of oxygen [superoxide (O-2), hydrogen peroxide (H2O2), and hydroxyl (OH.)] have been demonstrated to be involved in the peroxidation of membrane lipids consequently altering membrane composition, morphology, and function. Of all the lines of defense adopted by living organisms against toxic oxygen free radicals, vitamin E is most effective in the prevention of membrane damage. Cardiopulmonary bypass (CPB) has been shown to activate complement and cause sequestration of leukocytes which can recruit, adhere, and stimulate release of cytotoxic oxygen radicals. A prospective study of 30 patients evaluated the effects of CPB with and without an exogenous free radical scavenger (Group I, N = 20, control) and (Group II, N = 10, vitamin E) on H2O2 (a marker of oxygen free radicals) malonaldehyde (a marker of lipid peroxidation), transpulmonary leukosequestration, and plasma levels of vitamins E and C. Group I showed a progressive increase in H2O2 during CPB from 65 +/- 6 to 130 +/- 11 micron/ml (P less than 0.0001); plasma vitamin E decreased from 15 +/- 3 to 6 +/- 1 mg/liter (P less than 0.0001) while vitamin C increased from 1.6 +/- .3 to 2.3 +/- .3 mg/dl (P less than 0.0001). Group II showed no significant increase in H2O2 (from 78 +/- 8 to 93 +/- 5 microns/ml) during CPB and a significant reduction in H2O2 levels compared to Group I (P less than 0.001); plasma vitamins E and C did not change significantly in Group II.(ABSTRACT TRUNCATED AT 250 WORDS)
Ascorbic Acid↗
Xenograft seeding of Dacron grafts in dogs.
The benefit of autologous endothelial cell seeding in dogs has been widely accepted. This experiment seeks to determine if a similar effect accompanies the use of xenograft (porcine) endothelial cells in dogs. Thirty-two mongrel dogs underwent thoracoabdominal aortic bypass with 25- to 30-cm segments of double velour Dacron 8-mm grafts. Endothelial cell seeding was performed with whole blood suspensions of either autologous endothelial cells (Group I) or heterologous endothelial cells from pigs (Group II). Cell-free culture medium was added to whole blood for preclotting in unseeded control animals (Group III). Ten animals in each group were sacrificed at 30 days and all grafts were patent. Thrombus-free surface areas were Group I = 61.7 (+/- 6.4%, SEM); Group II = 53.2 (+/- 6.8%, SEM); and Group III 42.2 (+/- 8.0%, SEM). There was a significant difference between autologous-seeded and unseeded grafts (P less than 0.04). Endothelialization was confirmed by scanning and transmission electron microscopy in all groups but was better in both seeded groups: Group I-9/10 grafts, Group II-8/10 grafts, and Group III-4/10 grafts. Factor VIII immunofluorescent staining confirmed the presence of endothelium on selected grafts in each group. These results raise questions concerning the proposed mechanism of endothelial seeding since xenograft cells seem to facilitate healing in the canine model. If heterograft cells can be effective, it may not be necessary to harvest cells from the recipient in order to achieve the benefits of seeding.
Animals↗
Identification of new collagen formation with 125I-labeled antibody in bovine pericardial tissue valves implanted in calves.
Failure of bovine pericardial tissue valve used in young patients may be due to a slow rejection process. Polyclonal anticollagen (Type I) antibody (IgG) was made in rabbits and purified by protein A affinity column. Two milligrams of IgG was labeled with 2 mCi of 125I by the Iodogen method. Free iodide was separated by G-10 column. Affinity of 125I-IgG was checked by radioimmunoassay. Two hundred and fifty microcuries of 125I-IgG was injected in calves immediately after tissue valve implantation, and the calves were killed 4 h post-injection. After harvesting the valve, each of the three leaflets was separated into four zones, and radioactivity in each section was mapped with a gamma counter. The radioactivity in tissue valve section was compared to that of normal aortic valve. The sections of tissue valve retain five to ten times more 125I-IgG than control aortic valve. Iodine-IgG thus provides a sensitive technique for determination of residual antigenicity in tissue valve.
Animals↗
Percutaneously adjustable pulmonary artery band.
Conventional banding techniques result in up to 50% mortality as a result of improper and fixed constriction of the pulmonary artery in patients in unstable condition. We developed a percutaneously adjustable band with a fluid-filled reservoir that allows variable constriction without thoracotomy or other surgical procedures. Six pigs ranging in weight from 7 to 10 kg underwent pulmonary artery banding. Swan-Ganz catheterization, ultrasound studies, and Doppler studies were used to adjust and monitor the pressure gradient across the band. Thirty days after banding, the pigs were killed; their hearts were sectioned, weighed, and compared with hearts from a control group of six pigs weighing 11 to 13 kg. The ratio of mean total heart weight to total body weight (X 10(-3] was 6.3 +/- 0.7 in the banded group and 4.4 +/- 0.3 in the controls (p less than 0.001). The ratio of left ventricular weight to right ventricular weight was 0.76 +/- 0.1 in the banded group and 1.6 +/- 0.1 in the controls (p less than 0.001). The thickness of the right ventricular free wall was 4.9 +/- 0.5 mm in the banded group and 2.6 +/- 0.5 mm in the controls (p less than 0.001). Right ventricular free wall weight in the banded group was 25.9 +/- 5.8 gm compared with 11.1 +/- 1.3 gm in the controls (p less than 0.001). These results demonstrate the effectiveness of the band in inducing right ventricular hypertrophy. Since the band is easily placed and simply adjusted percutaneously, this device promises to be of importance clinically in improving the safety of pulmonary artery banding procedures.
Animals↗
Quantification of regional platelet and calcium deposition on pericardial tissue valve prostheses in calves and effect of hydroxyethylene diphosphonate.
Mitral valves were replaced with 25 mm bovine pericardial tissue valve prostheses (Ionescu-Shiley) in 45 calves (23 controls and 22 treated daily with hydroxyethylene diphosphonate). Before being killed 1, 14, 30, and 90 days later, the calves received In-labeled autologous platelets intravenously. Regional variations in platelet deposition were measured by a new technique. Thrombus was noted early on the flexion zone of the valve; with time it increased on the free edge and central zone. Platelet deposition was initially high on the flexion zone, attachment zone, sewing ring, and perivalvular tissue but decreased with time. Hydroxyethylene diphosphonate treatment tended to decrease platelet deposition in all zones. Calcium content was high in thrombus and increased in all zones with time, in both groups, but the deposition was less in the group treated with hydroxyethylene diphosphonate. Collagenous tissue and adherent thrombus appear to provide nucleation sites for calcification.
Animals↗
Influence of antioxidants (mannitol and allopurinol) on oxygen free radical generation during and after cardiopulmonary bypass.
Oxygen-derived free radicals (O2-, H2O2, OH.) are produced during oxidative metabolism, ischemia and reperfusion, and cardiopulmonary bypass (CPB). When oxygen free radical production exceeds scavenging capacity, peroxidation of structural lipids in cell membranes can occur with potentially injurious consequences. In this prospective study, 45 patients were evaluated to determine the effect of CPB on oxygen free radical generation. Twenty patients in group I were controls. Exogenous oxygen free radical antioxidants were administered before bypass to patients in group II (n = 15, mannitol) and group III (n = 10, allopurinol). In group I, plasma H2O2 increased during extracorporeal circulation from 65 +/- 6.0 to 125 +/- 12 microM/ml (p less than .001). At similar sampling intervals, plasma H2O2 levels were significantly lower in group II (p less than .03) and group III (p less than .05) when compared with those in group I. Red blood cell H2O2 did not change in group I or group II. White blood cell H2O2 levels decreased in group I (p less than .04) and group II during CPB. (Intracellular concentrations of H2O2 were not obtained in group III patients). We conclude that cytotoxic oxygen radicals are generated during CPB and that pretreatment with free radical antioxidants, mannitol or allopurinol, may minimize the free radicals available for lipid peroxidation of biomembranes.
Allopurinol↗
The International Society for Heart Transplantation Registry.
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Adolescent↗
Complement activation during cardiopulmonary bypass. Comparison of bubble and membrane oxygenators.
A prospective randomized trial involving 91 patients undergoing cardiopulmonary bypass compared the effects of bubble oxygenators (with and without methylprednisolone sodium succinate) and membrane oxygenators on complement activation and transpulmonary sequestration of leukocytes. Patients were divided as follows: Group I, 30 patients, bubble oxygenator; Group II, 31 patients, bubble oxygenator and methylprednisolone sodium succinate (30 mg/kg); Group III, 30 patients, membrane oxygenator. In Group I, C3a increased from 323 +/- 171 ng/ml during cardiopulmonary bypass to 1,564 +/- 785 ng/ml at 25 minutes after bypass (p less than 0.0001). A significant decrease in C3a was found in Groups II and III compared to Group I (p less than 0.0001). C5a did not change significantly during cardiopulmonary bypass in any group. Reestablishment of pulmonary circulation at the end of bypass produced significant transpulmonary leukocyte sequestration in Group I; the median cell difference was 1,700/microliter. Transpulmonary sequestration was significantly (p less than 0.0001) less in Group II (median cell difference = 200/microliter) and in Group III (median cell difference = 400/microliter) than in Group I. We conclude that cardiopulmonary bypass with a bubble oxygenator alone initiates significantly (p less than 0.0001) more C3a activation and leukocyte sequestration than when methylprednisolone sodium succinate (30 mg/kg) is given 20 minutes before the start of cardiopulmonary bypass with a bubble oxygenator or when a silicone membrane oxygenator is used.
Adrenal Cortex Hormones↗
Quantification of deposition of neutrophilic granulocytes on vascular grafts in dogs with 111In-labeled granulocytes.
A new radioisotopic technique has been developed for quantification of deposition of neutrophilic granulocytes on vascular grafts. Nine healthy mongrel dogs underwent bilateral femoral artery resection and reconstruction with grafts of femoral vein and Gore-Tex. Pure granulocytes that had been separated from whole blood by centrifugal elutriation were labeled with 111In-tropolone in plasma. The granulocyte harvesting efficiency was 25 +/- 12%, and the labeling efficiency was 87 +/- 7%. Three hours after injection of labeled granulocytes and 2 hours after reperfusion, the grafts were harvested and cut into several segments for study of areas of anastomoses and midsections. On the basis of the radioactivity in the blood and in anastomotic and graft sections, the area of graft sections, and the neutrophilic granulocyte and differential leukocyte counts, the number of neutrophilic granulocytes adherent to a unit area and the total number of neutrophilic granulocytes on graft sections were calculated. These quantifications of the deposition of neutrophilic granulocytes indicated that the midsections of Gore-Tex grafts retained more neutrophilic granulocytes than did the midsections of vein grafts. Although the anastomotic areas retained more neutrophilic granulocytes than did the midsections of vein grafts, the opposite finding prevailed for the Gore-Tex grafts. A major fraction of neutrophilic granulocytes on Gore-Tex grafts was incorporated into thrombus. Semiquantitative information obtained by scintigraphy of the deposition of neutrophilic granulocytes on vascular grafts also confirmed this observation.
Animals↗
Cardiac function following prolonged preservation and orthotopic transplantation.
Donor dog hearts perfused with whole blood were preserved ex vivo, beating, for 12 hours before orthotopic implantation. Twenty-four to 48 hours following implantation, ventricular function was studied using sonomicrometric techniques and compared to that of acutely denervated and conventionally preserved transplanted hearts. Hearts preserved ex vivo for 12 hours and then implanted in an orthotopic position had ventricular function statistically equal to or better than acutely denervated or conventionally preserved transplanted hearts.
Animals↗
Platelet deposition on and calcification of bovine pericardial valve.
Platelet deposition on bovine pericardial mitral valves was quantified in healthy adult mongrel dogs at 1, 14 and 30 days post-implantation and 24 h after i.v. injection of 400-500 microCi of autologous 111In-platelets. In vitro quantitation of platelet deposition on components of the prosthesis indicated maximal activity at one day with a successive decrease in activity at 14 and 30 days. At one day, platelet-associated radioactivity on the sewing ring was 3-4 times as great as on the leaflets, but at 14 and 30 days this had dropped to approximately half of the value on the leaflets. Calves underwent mitral valve replacement with a bovine pericardial valve. Thirty days post-operatively, 111Indium labeled labeled platelets were administered i.v.; 24 h later, calves were sacrificed and sections of each valve leaflet were analyzed for platelet and calcium deposition. Platelet deposition per mm2 of surface was greatest at the free edge of the leaflet, followed by the central zone and flexion point. Calves treated with sodium hydroxyethylene diphosphonate (5 mg kg-1 day-1 s.c.) had reduced platelet deposition but no reduced calcium content on the valves after 30 days compared with untreated calves. In flow chamber studies, platelet deposition from the heparinized blood of normal calves was significantly less on the smooth (inner) than on the rough (outer) surface of fixed bovine pericardium.
Animals↗