摘要:

Background The adaptive growth of the transplanted heart within the growing child may contribute to long-term cardiac performance. The ability to achieve increased ventricular volume and appropriate muscle mass in the face of immunosuppression and cardiac denervation has not been studied. We previously reported normal left ventricular (LV) volume growth over a 3-year period after cardiac transplantation. This study was designed to assess changes in LV mass and mass/volume ratio and their relation to LV end-diastolic pressure (LVEDP) 1 to 4 years after cardiac transplantation.Methods and Results Cardiac transplantation was performed in 18 patients, age 7 days to 18 years (median, 3.7 years). The indications for cardiac transplantation were cardiomyopathy (8 patients), hypoplastic left heart syndrome (7 patients), and postoperative structural congenital heart disease with ventricular failure (3 patients). The mean follow-up was 48 months, with a range from 29 to 70 months. Serial annual catheterizations were performed after 1 year (16 patients), 2 years (18 patients), 3 years (15 patients), and 4 years (8 patients). Cardiac index (Fick), LVEDP (baseline and after 10-mL/kg saline infusion delivered over 5 minutes), and systemic vascular resistance (SVR) were measured. LV diastolic volume index (LVDVI), LV mass index, and mass/volume ratio were determined angiographically according to the method of Lange and Rackley. The data were analyzed by repeated- measures ANOVA. Least-squares means and group SEM were calculated. No change in cardiac index, SVR, or baseline LVEDP was noted. The LVEDP doubled after fluid challenge, suggesting a restrictive process. The LVDVI remained near 60 mL/m2. The LV mass/volume ratio remained one.Conclusions Appropriate increases in muscle mass occurred after cardiac transplantation, preserving normal mass/volume ratios despite somatic growth deficits associated with immunosuppressive therapy and denervation of the donor heart.(Circulation. 1994;90(part 2):II-61-II-65.)

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Background Mechanical circulatory support for intractable heart failure as a bridge to transplantation has been used infrequently in children.The lack of clinically available ventricular assist devices has resulted in the use of conventional extracorporeal circuits with oxygenator as the main modality for circulatory support. In this study we reviewed our experience with extracorporeal membrane oxygenation (ECMO) support in children with irreversible heart failure who were awaiting heart transplantation.Methods and Results Since 1985, 14 children were placed on ECMO support for circulatory failure and were considered candidates for heart transplantation:8 children had postcardiotomy contractile failure, 3 had dilated cardiomyopathy, and 3 had viral myocarditis. Five of these children had cardiac arrest and were placed on support during cardiopulmonary resuscitation. Mean duration of ECMO support was 109+-20 hours. Eight patients developed pulmonary edema requiring decompression of the left ventricle, 3 by blade atrial septostomy and 5 by left atrial vent cannula. Nine of 14 received a heart transplant, 1 child recovered spontaneously (myocarditis), and 4 died of sepsis on ECMO. Of the children who received transplants, 6 were early survivors with 1 late death (lymphoproliferative disease), for a total of 7 of 14 (50%) early and 6 of 14 (43%) late survivors.Conclusions Our experience suggests that ECMO is an effective means of circulatory support as a bridge to transplantation in children.Decompression of the left ventricle is often required to prevent pulmonary edema. Sepsis and bleeding remain a limitation to prolonged mechanical support with ECMO in children. (Circulation. 1994;90(part 2):II-66-II-69.)

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Background Acute vascular rejection (AVR) is characterized by vascular injury and systolic graft dysfunction and is often associated with elevated panel reactive antibodies (PRAs) to HLA antigens.Plasmapheresis has been shown to improve the otherwise poor prognosis of AVR, but its use is often complicated and limited by hypotension.Methods and Results In three cardiac transplant recipients with severe hemodynamic compromise during AVR, refractory to standard therapy, extracorporeal immunoadsorption was performed using a protein A column.Plasma was removed at 10 to 20 cm3/min, passed through the column, and reinfused. All three patients had negative pretransplant PRAs. PRA rose before or during AVR and became negative in all three patients following immunoadsorption. Time course and number of treatments required to decrease PRA to <5% varied. Concomitant with a decrease in PRA, histological findings and ventricular function improved and normalized. Ejection fraction rose from 23+-2 to 56+-8% and shortening fraction from 14+-7 to 36+-7%, P<.05 (both). One patient died from infection 2 months after resolution of AVR; the other two patients are alive 25 and 31 months after AVR with normal left ventricular function and coronary arteries. In both, since initial immunoadsorption course, PRA has remained negative and no rejection has occurred. In two patients, a circulating donor-specific or donor-related anti-HLA class I antibody was identified and removed by protein A column.Conclusions Our preliminary data suggest that (1) immunoadsorption is effective in removing circulating immunoglobulins and is well tolerated; (2) AVR is preceded by or associated with circulating antibodies against HLA class I antigens; (3) their removal is temporarily associated with recovery of graft function and normalization of biopsy; and (4) anti-HLA class I antibodies can mediate vascular injury if they appear in the post-transplant period. (Circulation. 1994;90(part 2):II-70-II-73.)

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Background Because of the critical shortage of adult donor hearts, many recipients die awaiting transplantation of an organ of appropriate size.Undersized hearts (donor/recipient weight ratio <0.7) have been used for heterotopic heart transplantation. We report on 6 moribund adult heart transplant candidates who were rescued with orthotopic heart transplantation of undersized pediatric hearts.Methods and Results Recipients were hypotensive (mean blood pressure, 62.3+-13.4 mm Hg), had high pulmonary artery pressures (mean pulmonary artery pressure, 42.4+-6.3 mm Hg), and had mean cardiac indexes of 1.7+-0.6 L min-1m-2. Four had pretransplant intra-aortic balloon pumps, and one was on a Thoratec left ventricular assist device complicated by fungemia. Since conventionally sized donors were unavailable (+-30% recipient weight), the patients were listed in a wider weight range (+-60%). Donor characteristics were age, 8.7+-1.5 years; weight, 32.8+-7.0 kg; and donor/recipient weight ratio, 0.44+-0.2, with average ischemic time of 236.0+-59.3 minutes. Technical considerations during transplantation included (1) opening the donor right atrium from the inferior vena cava to superior vena cava to facilitate size matching, (2) performing size-mismatched pulmonary artery and aortic anastomoses end to end, (3) infusing prostaglandin E112 ng kg-1min-1to decrease pulmonary and systemic vascular resistance, (4) pacing donor and recipient atria synchronously to improve ventricular filling, (5) maintaining high heart rates up to 140 beats per minute (initially with isoproterenol or pacing, chronically with theophylline), (6) hyperventilating with sedation and paralysis as necessary, (7) reperfusing with triiodothyronine, and (8) minimizing afterload. All patients were discharged from the hospital. At 1 week, hemodynamics were normal and echocardiograms demonstrated left ventricular growth.Conclusions Hence, undersized pediatric hearts can be used successfully to salvage moribund patients and expand the potential donor pool for adult orthotopic heart transplantation.(Circulation. 1994;90(part II):II-74-II-77.)

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Background Cardiac allograft vasculopathy remains the leading limitation to long-term survival after cardiac transplantation. While the influence of donor and recipient gender in the pathogenesis of cardiac vasculopathy is still poorly understood, studies have indicated that female allografts may be at higher risk for the development of cardiac allograft vasculopathy. The purpose of this study was to characterize the influence of donor and recipient gender on the early genesis of cardiac allograft vasculopathy by using intravascular ultrasound.Methods and Results Thirty-six consecutive cardiac transplant recipients were divided into three groups on the basis of donor and recipient gender as follows: group 1, female donor and male recipient (n=8); group 2, male donor and female recipient (n=7); and group 3, male donor and male recipient (n=21). The three groups were similar with regard to donor and recipient age, weight, body surface area, serum lipids, left ventricular function, histocompatibility, cellular and vascular rejection, and cytomegalovirus infection. To precisely quantitate the extent of cardiac allograft vasculopathy, intravascular ultrasound was performed in all patients at the time of first annual angiography. Intimal thickening and intimal index were accurately quantitated by intravascular ultrasound. Intimal thickening was significantly greater in group 1 (0.55+-0.15 mm) than in group 2 (0.18+-0.04 mm) or group 3 (0.29+-0.05 mm) (P<.05). In addition, the intimal index was greater in group 1 (0.20+-0.04) than in group 2 (0.07+-0.02) or group 3 (0.15+-0.02) (P<.01, group 1 versus group 2).Conclusions Male recipients of female allografts have a higher degree of vascular intimal hyperplasia detected by intravascular ultrasound at 1 year after heart transplantation.These findings indicate that donor and recipient gender influences the early genesis of cardiac allograft vasculopathy. (Circulation. 1994;90(part 2):II-78-II-82.)

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Background The implantable left ventricular assist device (LVAD) was designed to provide circulatory support as an alternative to heart transplantation or to continued medical therapy of end-stage heart failure. Initial experience with the implantable LVAD used as a bridge to heart transplantation provides a clinical opportunity to study the function of the device and adaptation by the patient.Methods and Results Nineteen heart transplant candidates (mean age, 50 years; 17 males) underwent insertion of the HeartMate LVAD as a bridge to heart transplantation from December 1991 to November 1993.All patients were in cardiogenic shock on inotropes, and 16 (84%) were on an intra-aortic balloon pump. Three patients died because of multiple organ failure; all had right ventricular (RV) dysfunction (2 required RV assist devices). Sixteen patients (84%) improved markedly and were rehabilitated to New York Heart Association functional class I-II. Three patients are still on support. Significant improvements in hemodynamic function (based on analysis of the percent change from pre-LVAD condition to pretransplantation) were observed: cardiac index rose from 1.6+-0.2 to 3.2+-0.9 L/min per m21100 patient days of support.1 year) was not tested, so questions regarding long-term device reliability and the chronic risk of infection are unknown. (Circulation. 1994;90(part 2): II-83-II-86.)

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Background Although numerous left ventricular assist devices (LVADs) have been used clinically, frequent thromboembolic complications have been reported despite the smooth interior LVAD surfaces and systemic anticoagulant medication.In contrast, the Thermo Cardiosystems HeartMate 1000 IP LVAD has textured interior surfaces that are promptly covered by a densely adherent neointima. We hypothesize that elimination of a direct interface between prosthetic material and blood elements reduces the risk of peripheral embolization and minimizes the necessity for systemic anticoagulant medication. This report defines the thromboembolic risk of this type of LVAD and characterizes the nature and effectiveness of the various anticoagulation regimens that were tested during the initial clinical trial with this device.Methods and Results All values are reported as mean+-SD. Fifty-four males and three females with an average age of 47+-11 years were supported with the HeartMate 1000 IP LVAD for an average of 62+-76 days at 11 clinical centers in the United States. Patients were prospectively evaluated for thromboembolic complications. Five different anticoagulation regimens were used during the first 4 postoperative weeks: no anticoagulants, low-molecular-weight dextran, heparin, dipyridamole plus aspirin, or miscellaneous agents. After the first 4 weeks, the patients were treated with aspirin plus dipyridamole or miscellaneous agents. Prothrombin time (PT), partial thromboplastin time (PTT), and fibrinogen values for the patients were measured at 0.1, 1, 2, 4, 8, 12, 16, 20, 24, 32, and 46 weeks during support. Two patients (3.5%) suffered thromboembolic cerebrovascular complications, an incidence of 0.2 episodes per patient-year of observation. One episode was due to fungal vegetation developing on the device and the other was due to embolization from a previously placed native mechanical aortic valve prosthesis. In the absence of infection, there were no device-related thromboembolic complications. Mean prothrombin time for all groups was 13.3+-0.5 seconds with no significant intergroup differences. Mean partial thromboplastin time during the first 4 weeks for the heparin-treated group was 53.3+-6.6 seconds, which was significantly longer than for all other groups, but fell to control values after heparin was discontinued at 4 weeks. Mean fibrinogen level for all groups was 370+-48 mg/dL, with no intergroup differences.Conclusions The HeartMate 1000 IP LVAD provides adequate circulatory support with a low risk of thromboembolism despite minimal systemic anticoagulation.The use of textured surfaces may be an important factor contributing to the low observed risk of thromboembolic complications. (Circulation. 1994;90(part 2):II-87-II-91.)

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Background Left ventricular (LV) assist device (LVAD) support has been associated with right ventricular (RV) failure in humans, but the etiology remains unknown.Mechanical LV support apparently does not induce RV pump failure in normal hearts, but controlled studies of LV assistance in hearts with preexistent RV dysfunction have been limited. Therefore, this study was performed to determine if LVAD support impairs RV systolic mechanics during acute RV ischemia.Methods and Results Five closed-chest, autonomically blocked, sedated dogs were studied after placement of an LVAD (LV-femoral artery bypass), right coronary artery (RCA) occluder, and 27 miniature radiopaque tantalum markers into the LV and RV walls for independent computation of RV and LV volumes. Biplane videofluoroscopic marker images and hemodynamic data were recorded before RCA occlusion with the LVAD off (maximum LV pressure (LVP (max))=119+-25 mm Hg), after 3 minutes of RCA occlusion with the LVAD off (LVPmax=84+-18 mm Hg), and then with the LVAD on (LVPmax=26+-32 mm Hg). Global RV contractility (end-systolic elastance (RV Ees) and preload recruitable stroke work (RV PRSW)), RV power output, and the mechanical (pump) efficiency of converting potential energy to external work (ratio of RV stroke work/total pressure-volume area) were calculated. As expected, with RCA occlusion there were major decreases in RV Ees.80). Pulmonary artery input impedance (RV afterload) decreased from 848+-628 to 673+-577 dyne sec (-1) cm-5(P<.01), which led to a 26+-29% improvement in RV pump efficiency (P<.001).Conclusions While right coronary artery occlusion significantly reduced RV systolic performance, LVAD support during acute RV ischemia did not further impair RV contractility or power output.Furthermore, since RV afterload fell with LV unloading, the mechanical pump efficiency of the right ventricle actually improved. These observations demonstrate that LVAD support does not directly induce RV failure in canine hearts with acute isolated RV ischemia. (Circulation. 1994;90(part 2):II-92-II-101.)

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Background Long-term clinical and hemodynamic benefits of dynamic cardiomyoplasty (DC) have been reported. However, no information is available about long-term morphological changes in the wrapped latissimus dorsi (LD) muscle in humans.Methods and Results The LD muscle flap was evaluated by magnetic resonance imaging (MRI) in 13 patients submitted to dynamic cardiomyoplasty for treatment of severe dilated cardiomyopathy.Eight patients were studied 15 days after the surgery (group 1) and 5 patients were studied from 24 to 52 months after the surgical procedure at the time of the cardiomyostimulator replacement (group 2). In the interim, LD was stimulated with burst of 6 pulses (duration, 185 milliseconds; burst frequency, 30 Hz) synchronized to every cardiac contraction, with a maximum of 100 LD contractions per minute. Images were acquired on a GE Sigma 1.5-T system (echo time, 25 milliseconds; repetition time, R-R x 2; slice thickness, 8 mm). The thickness of the LD decreased from 19.6+-7.3 mm for group 1 to 7.6+-0.8 mm for group 2 (P<.01). In addition, the signal intensity of the LD was compared with that of thoracic skeletal muscle and was found to be significantly increased in group 2 (2.19+-0.42) compared with group 1 (1.04+-0.07, P<.001). The signal intensity for group 2 on the T1-weighted images was similar to that of subcutaneous fat in those images.Conclusions Morphological changes in the wrapped LD muscle consistent with fatty degeneration occur after DC and can be detected by MRI.Further studies will be necessary to demonstrate the clinical significance of such LD muscle flap changes. (Circulation. 1994;90(part 2):II-102-II-106.)

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Background The main causes of death in patients with severe cardiomyopathy are progressive heart failure and sudden death.The influence of cardiomyoplasty on the incidence of sudden death and arrhythmias in patients with cardiomyopathy remains unclear. The aim of this study was to investigate the occurrence of arrhythmias and sudden death after cardiomyoplasty.Methods and Results We studied 32 patients (26 male, 6 female; mean age, 48+-12 years) who submitted to cardiomyoplasty for treatment of heart failure in New York Heart Association (NYHA) class III (n=24) or class IV (n=8). The etiology was idiopathic dilated cardiomyopathy in 27 patients, ischemic heart disease in 3 patients, and Chagas' heart disease in 2 patients. Patients were routinely studied before and every 6 months after cardiomyoplasty by means of radioisotopic angiography and 24-hour Holter monitor recordings. There were no operative or immediate postoperative deaths. During the postoperative period, 5 patients presented with acute atrial fibrillation and 1 had an episode of sustained ventricular tachycardia. All episodes were successfully treated with intravenous antiarrhythmic drugs or cardioversion. During follow-up (from 2 to 66 months), 15 patients died from sudden death (n=5) or progressive heart failure (n=10). Survival rates at 1, 2, and 4 years were 79.9+-7%, 62.5+-9.7% and 35+-12.1%, respectively. At 6-month follow-up, NYHA functional class improved from 3.2+-0.4 to 1.7+-0.6 (P=.001) and left ventricular ejection fraction increased from 19.8+-3.3% to 24+-8.2% (P=.004). The mean values per day of premature ventricular complexes (PVCs) and episodes of nonsustained ventricular tachycardia (NSVT) did not change statistically. The mean number of PVCs per 24 hours before and at 6, 12, 24, 36, and 48 months after surgery were 126+-44, 96+-33, 90+-29, 81+-35, 71+-35, and 59+-48. The mean number of episodes of NSVT per 24 hours before and at 6, 12, 24, 36, and 48 months after surgery were 3.3+-1.3, 1.9+-0.5, 1.3+-0.5, 1+-0.5, 1.5+-1.1, and 0.6+-0.5, respectively. With respect to analysis of the idiopathic dilated cardiomyopathy subgroup, there also were no significant differences in the incidences of pre- and postoperative arrhythmias.Conclusions Despite NYHA functional class and left ventricular function improvements observed after cardiomyoplasty, the incidence of arrhythmias did not change, and sudden death was an important finding mainly in late fol low-up. The problem of sudden death after cardiomyoplasty, the mechanism that produces it, and the means to prevent it remain critical areas for future research. (Circulation. 1994;90(part 2):II-107-II-111.)

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID