LVAS pump performance following initiation of left ventricular assistance

Prevention of disturbed flow (e.g., flow stasis) and consequent thrombosis in heart pumps is based upon design characteristics determined during laboratory bench tests. These tests employ optimal filling and emptying characteristics, such as the full-fill to complete empty mode in the Novacor left ventricular assist system. Filling characteristics of the Novacor LVAS were examined during the first 48 hours after implantation in 14 patients. Fill volume of the pump was reduced in pathologic states, such as cardiac tamponade, and following the initiation of right ventricular mechanical circulatory support. In addition, multiple regression analysis revealed that right ventricular function measured by the amount of inotropic support required, the right ventricular ejection fraction, and the total pulmonary resistance, significantly predicted left ventricular assist pump fill volume during the first 48 hours of support. Flow visualization simulating these clinical conditions of incomplete filling suggest inadequate valve washing, particularly around the inlet valve and its conduit, which may predispose to thrombus formation.

Biomaterial associated impairment of local neutrophil function

The effect of biomaterials on neutrophil function was studied in vitro to determine if these materials activated neutrophils and to determine the subsequent response of these neutrophils to further stimulation. Two biomaterials--polyurethane, a commonly used substance, and Velcro pile (used in the Jarvik 7 heart)--were evaluated. Two control substances, polyethylene and serum-coated polystyrene, were used for comparison. Neutrophil superoxide release was measured following incubation with these materials for 10, 30, and 120 min in the absence of additional stimulation and after stimulation with formylmethionylleucylphenylalanine (fMLP) or phorbol myristate acetate (PMA). The authors observed that the incubation of neutrophils on both polyurethane and Velcro resulted in substantially increased superoxide release that was greater after the 10 min than after the 30 or 120 min association. These activated neutrophils exhibited a poor additional response to fMLP but responded well to PMA. The effect of implantation of the Novacor left ventricular assist device on peripheral blood neutrophil function was also evaluated. The peripheral blood neutrophils exhibited normal superoxide release and chemotaxis. These studies suggest that biomaterials may have a profound local effect on neutrophils, which may predispose the patient to periprosthetic infection, but that the reactivity of circulating neutrophils is unimpaired.

Propagation of infiltrating lymphocytes and graft coronary disease in cardiac transplant recipients

The pattern of lymphocyte growth from endomyocardial biopsies in 55 heart transplant recipients was shown to be correlated with the subsequent development of graft coronary disease. Persistent lymphocyte growth was observed in 39 patients, and 15 of these growers (or 41%) developed graft coronary disease. In contrast, only 1 of 15 patients (or 6%) with nongrower biopsies showed subsequent graft coronary disease. Thus, biopsy growth was associated with a higher incidence of subsequent GCD (p = 0.02). A comparison between the group of 15 growers with subsequent graft coronary disease and the 24 growers without subsequent graft coronary disease did not show any differences with respect to patient age, presence of coronary artery disease in the native heart, biopsy histology, donor alloreactivity of biopsy grown lymphocytes, and immunosuppressive drug regimen. On the other hand, the number of treated rejection episodes was significantly lower in the grower group with subsequent graft coronary disease (p = 0.04). These data support the concept that graft coronary disease may involve rejection and that more immunosuppression may lower its incidence. This concept is strengthened by findings showing that alloreactive T cells can be propagated from coronary arteries of cardiac allografts with graft coronary disease.

Comparative trial of immunoprophylaxis with RATG versus OKT3

A randomized trial of rabbit antithymocyte globulin (polyclonal) versus OKT3 monoclonal antibody prophylaxis was carried out in 82 heart transplant recipients, who, in addition, received baseline immunosuppression with cyclosporine, azathioprine, and prednisone. One-year actuarial survival was comparable between groups (95% to 98%), but the likelihood of histologic rejection within the first 30 days of transplant was more than seven times greater in OKT3 patients (0.58/patient vs 0.08/patient). Patients receiving OKT3 were more likely to have repeated episodes of rejection, and the mean time to rejection for patients receiving OKT3 was shorter (33 days) than for patients receiving rabbit antithymocyte globulin (67 days). At 120 days, while 52% of patients receiving rabbit antithymocyte globulin were free of rejection, versus 37% of the OKT3 patients, the difference was not significant. There was no difference in the incidence of major or minor bacterial or viral infection between groups, but significant hemodynamic side effects were seen after the first dose of OKT3, and aseptic meningitis developed in two OKT3 patients.

The scalar electrocardiogram of the orthotopic heart transplant recipient

The 12-lead scalar electrocardiograms of heart transplant recipients were examined prior to hospital discharge (N = 191), and at 1 (N = 162), 2 (N = 97), and 3 years (N = 46) after transplantation. At the pre-discharge point, 46% had right bundle branch block (RBBB) QRS morphology (QRS duration greater than or equal to 120 msec: 20 patients, less than 120 msec: 67 patients). This finding tended to be manifest on the first day following transplantation; its prevalence remained constant over 3 years of follow up. Rejection, ischemic time, preoperative pulmonary vascular resistance, and donor age were not associated with the presence of RBBB morphology. A subgroup of 46 consecutive patients (21 with RBBB morphology) underwent right-sided heart catheterization and radionuclide angiography prior to discharge. RBBB morphology was not associated with any hemodynamic abnormality at catheterization. Based on the radionuclide study, RBBB morphology was associated with a greater left anterior oblique angle required for the best visual separation of the ventricles during acquisition of the study (angle of interventricular septal plane to sagittal plane: 69 +/- 11 versus 59 +/- 9 degrees; p = 0.019), and with the presence of right ventricular dysfunction (13 of 21 versus 6 of 25 patients; p = 0.009). The high prevalence of RBBB morphology in heart transplant recipients appears to be related to posterior rotation of the long axis of the heart in the transverse plane, probably resulting from the surgical technique, and to right ventricular dysfunction.

Optimal perioperative immunosuppression in cardiac transplantation using rabbit antithymocyte globulin

A randomized trial of RATG (polyclonal) vs. OKT3 (monoclonal) antibody prophylaxis was carried out in 82 cardiac transplant recipients who, in addition, received baseline immunosuppression with cyclosporine, azathioprine and prednisone. One-year actuarial survival was comparable between groups (95% and 98%). The incidence of moderate or severe rejection within the first 30 days of transplant was over 7 times greater in patients receiving OKT3 vs. those receiving RATG. Patients receiving OKT3 were more likely to have repeated episodes of rejection and the mean time to rejection for patients receiving OKT3 was shorter (33 days) than for RATG patients (67 days). At 120 days, 52% of RATG patients were free of rejection while only 37% of the OKT3 patients were rejection-free. There was no difference in the incidence of major or minor bacterial or viral infection between groups. Patients receiving OKT3 showed a less-prolonged depression of the CD3 and CD4 T cell subsets than did those receiving RATG. Significant hemodynamic side-effects were seen after the first dose of OKT3 and there was a 5% incidence of aseptic meningitis associated with its use.

Experience with univentricular support in mortally ill cardiac transplant candidates

Between July 1987 and March 1989, 11 patients underwent left ventricular support with the Novacor left ventricular assist system irrespective of apparent degree of right ventricular failure. The first 2 patients died of multisystem organ failure while on support. All the remaining patients survived the support period, and actuarial survival after transplantation was 100% at 6 months and 89% at 1 year. In no patient did bacterial infection develop during support or after transplantation. Right ventricular ejection fraction before implantation of the left ventricular assist system was lower than 15% in 6 of 8 patients, yet it increased twofold during left ventricular support. The need for excessive inotropic support (2 patients) or temporary (four days) mechanical right ventricular support (2 patients) while on the left ventricular support system appeared to be related to elevated pulmonary vascular resistance during support in association with large preimplantation ventricular volumes. It appears that even patients with compromised right ventricular performance can be supported long term with a left ventricular assist device. Patients with elevated pulmonary vascular resistance may require temporary right ventricular support.

Heart transplantation in diabetic recipients

Preexisting diabetes mellitus (DM) has been regarded as a contraindication to heart transplantation (HT). This prejudice has been based upon concern over increased infection rates and worsening DM with the initiation of prednisone immunosuppression. To better evaluate these suppositions, we reviewed our experience with diabetic patients who underwent HT. Between 6/80 and 1/88, 367 nondiabetics (NDs) and 19 diabetics underwent HT at our institution. Of the 19 diabetic recipients (DRs), two were black and four were female. Six DRs were on insulin (average daily dose: 46 U) prior to HT, and the remainder required oral hypoglycemic agents. Following HT, five DRs had insulin substituted for oral hypoglycemics. The 11 insulin-dependent DRs now require an average daily dose of 48 U. The average duration of follow-up for the 19 DRs was 17 months (range 1-67 months). During this time, 5 hospitalizations were required for complications of diabetes. The rejection rate was not higher for the DRs than the NDs (0.37 events/100 pt. days vs. 0.51 events/100 pt. days). The DRs who have undergone coronary angiography up to 4 years following HT have had no evidence of coronary atherosclerosis. Three-year survival for DRs and NDs is similar. DRs have a slightly higher incidence of lethal infections than NDs, which is not statistically significant (16% at 17 months vs. 10% (p greater than 0.4). We conclude that carefully selected diabetics can undergo HT with minimal consequent worsening of their DM. Diabetic HT recipients do not suffer a higher incidence of graft atherosclerosis, rejection, or lethal infection.

Disruption of the aortic anastomosis after heart-lung transplantation

Disruption of the aorta at the anastomotic site occurred in 4 of 66 consecutive heart-lung transplant recipients and was associated with a 100% mortality. In 3 of these patients, Candida either was cultured from the suture line or was seen in the wall of the aorta at postmortem examination. In 2 of these 3 patients, cultures of material from the donor trachea taken at the time of explanation grew Candida species. Two patients were seen with sudden massive hemorrhage on postoperative day 26 and postoperative day 28. One patient experienced acute decompensation due to right ventricular outflow tract obstruction on postoperative day 30, and the remaining patient was seen 7 months postoperatively with obstruction of both the left main bronchus and the right pulmonary artery caused by extrinsic compression by an aortic pseudoaneurysm. A high index of suspicion should be maintained when transplanting lungs containing Candida species, as we believe there is substantial evidence of donor transmission of the fungal agents. We now include amphotericin B in our antibiotic prophylactic regimen in an attempt to prevent fungal infection because previous treatment has been uniformly unsuccessful. Furthermore, we wrap both the trachea and the aorta with omentum to lessen the likelihood of mediastinal spread of infection to the aortic suture line.

Monoclonal versus polyclonal antibody therapy for prophylaxis against rejection after heart transplantation

Between August 1986 and December 1987, 88 patients received either RATG or OKT3 for immunoprophylaxis before heart transplantation. By the end of the first month after transplantation, 25% of the patients who received RATG had experienced a rejection episode compared with 43% of those receiving OKT3. This difference was persistent as many as 4 months after transplantation. While 50% of the OKT3 patients had a second episode of rejection, only 35% of the RATG patients did so. Randomization of these agents was complicated by severe cardiopulmonary side effects attributed to the first dose of OKT3. Five hours after the first dose of OKT3, a 25% drop in mean arterial pressure, accompanied by significant hypoxia, was seen in a majority of patients. There was no difference in the incidence of infection between the two groups.

Organ procurement for pulmonary transplantation

Selection of suitable donors is critical to the success of clinical pulmonary transplantation. Requirements for lung donors, management before explantation, and methods of preservation were reviewed for the 70 heart-lung, eight double-lung, and two single-lung transplantations performed at the University of Pittsburgh since 1982. Careful observation of trends of hyperoxygenation studies, chest roentgenograms, and Gram stain and culture results of tracheal secretions, as well as findings on bronchoscopy, can help identify which lungs not only have adequate function but are acceptable for transplantation. In spite of the rigid criteria used, 76% of tracheal cultures from donors deemed acceptable grew organisms. The presence of oropharyngeal flora has been shown to correlate with the development of early intrathoracic infections in the recipient. Prophylactic broad-spectrum antibiotic treatment of the donor is desirable to treat microbial contamination that could cause focal injury to the donor lung and predispose to infection in the recipient. Acceptance of less than ideal donors is ill-advised even though rejection of such donors conflicts with the current shortage of organs.

Resolution of severe pulmonary hypertension after heterotopic cardiac transplantation

In patients with severe congestive heart failure, a marked elevation in pulmonary vascular resistance limits the success of orthotopic cardiac transplantation, thus providing the rationale for heterotopic transplantation. To determine the changes in pulmonary hemodynamics after heterotopic cardiac transplantation, postoperative right heart pressures were serially measured in five patients who underwent this operation for end-stage congestive heart failure accompanied by severe secondary pulmonary hypertension and elevation in calculated pulmonary vascular resistance. Hemodynamics were compared with those of a matched group of 10 orthotopic cardiac transplant recipients. Preoperatively, pulmonary artery mean and wedge pressures, pulmonary vascular resistance and transpulmonary pressure gradient (pulmonary artery mean minus wedge pressure) were significantly higher in the heterotopic group. Postoperatively, significant improvement in pulmonary hemodynamics occurred in both groups and, by 12 months, the pulmonary artery mean pressure, wedge pressure, pulmonary vascular resistance and transpulmonary pressure gradient were similar in the two groups. These findings suggest that pulmonary hypertension secondary to congestive heart failure, even when severe and associated with a high pulmonary vascular resistance, is to a great extent reversible.

Lessons learned in pediatric heart transplantation

Between February 1, 1982, and June 30, 1988, 32 children underwent cardiac transplantation for treatment of congenital heart disease (10) and other cardiomyopathies (22). The 6-year actuarial survival was a disappointing 36% because of a high perioperative mortality (12 of 32, 37.5%) and because of five late deaths due to uncontrolable rejection. The perioperative mortality was a staggering 60% (6 of 10) for the patients with congenital heart disease. Four of the 6 recipients with congenital heart disease died because of acute failure of the donor right ventricle. This included 2 patients who required reconstruction of the pulmonary arteries for stenosis secondary to previous systemic-to-pulmonary shunts and 2 others in whom the pulmonary vascular resistances were underestimated because of undetected recent pulmonary emboli (1) and complicated pulmonary vascular anatomy (1). Five of the six late deaths were due to rejection-related events, and all were patients with acquired cardiomyopathy.

Infections in mortally ill cardiac transplant recipients

A total of 351 cardiac transplantations performed between June 1, 1980, and Sept. 30, 1987, were reviewed to determine if infectious complications were more frequent in those patients requiring preoperative intravenous inotropic support, placement of an intraaortic balloon pump, or mechanical support with a left ventricular assist device or total artificial heart. One hundred forty-nine transplants (45%) were performed in these mortally ill patients. There was no statistically significant difference between patients with and without infection within each support group for the following: the number of in-patient days awaiting a donor heart, the number of days receiving support, the percent of patients with preoperative tracheal intubation, the length of the operation, and the percent of patients requiring reoperation for bleeding. The need for invasive methods of support (intraaortic balloon pump, left ventricular assist device, or total artificial heart) in patients awaiting heart transplantation increases the prevalence of perioperative nonviral infection. Preoperative mechanical support with a left ventricular assist device or total artificial heart significantly increases the risk of infection-related mortality.

Characteristics of blood rheology in patients during Novacor left ventricular assist system support

Blood rheologic properties were studied in 11 patients on Novacor LVAS support (1-126 days) as a bridge to transplantation. Overall, these patients showed slight increases in mean blood viscosity and red cell rigidity. Their mean plasma fibrinogen was in the upper normal range. However, the degree of rheologic change observed, and the individual factors affected most, were unique to each patient and hemorheologic results correlated well with the patient's clinical status.

Evaluation of right ventricular function during clinical left ventricular assistance

Hemodynamic and mechanical parameters of right ventricular (RV) performance were measured in eight patients undergoing left ventricular (LV) assistance as a bridge to cardiac transplantation. All patients, even those with impaired RV performance, survived support and transplantation. The reduction of LV afterload produced by the left ventricular assist system (LVAS) results in RV afterload reduction, which permits even the marginal RV to function adequately during LVAS support.

Erythrocyte deformability in patients on left ventricular assist systems

Preliminary hemorheologic studies using clinical filtration techniques on blood cell suspensions have suggested that changes in erythrocyte (RBC) deformability occur during left ventricular assist system (LVAS) support. In the biophysics literature, it is generally accepted that the elastic properties of the RBC membrane complex affect the microcirculatory deformability of the whole cell (cytoplasmic pathologies excepted). This paper compares single cell measurements of the surface shear elastic modulus, mu, of the RBC membrane complex (determined using micropipette aspiration) to available clinical filtration pressure data during Novacor LVAS support, over 33 and 126 days in four patients.

The value of protective isolation procedures in cardiac allograft recipients

The impact of protective isolation on the incidence of infection in 60 cardiac transplant recipients (mean age, 49.2 years) was studied in a prospective randomized trial. Thirty patients were randomized to protective isolation, which consisted of private room, hat, mask, sterile gown, and handwashing. Thirty patients were randomized to no isolation, which meant they recovered in a crowded, open intensive care unit and were adjacent to recipients of liver transplants or patients who were on the trauma, neurosurgical, and general surgical services, many of whom had an infection of the incision or a pulmonary infection. There was no difference between groups in the proportion of patients in whom infection developed (chi 2[1] = 0.27; p = 0.6), the number of infection-related deaths (2 in each group), the types of infection (bacterial, viral, fungal, or protozoal), or the overall outcome. Because protective isolation offered no benefit over standard care in protecting these patients from infections or the associated complications, we have discontinued its routine use after cardiac transplantation.

Posttransplantation diabetes mellitus in heart transplant recipients

This study was undertaken to investigate the impact of diabetes, which develops after heart transplantation, on infection and patient survival. Nondiabetic patients (366) underwent heart transplantation at our institution between June 1, 1980 and January 12, 1988. Of these patients, 29 (8%) developed posttransplantation diabetes (PTD), defined as a continued need for hypoglycemic agents. The PTD group did not differ significantly from the nondiabetic recipients in age, sex, or human leukocyte antigen type. The average age in the PTD group was 49 years. Average length of follow-up was 21 months (range 4 to 46 months). Eighteen patients are maintained on insulin. Eight patients are on oral hypoglycemic agents. Three patients died while on insulin. The average prednisone dosage in this group is 0.23 mg/kg/day. There have been 18 minor infections and four potentially serious nonlethal infections in the 27 PTD recipients. One lethal infection occurred 33 months after heart transplantation. The only other fatality was related to metastatic bladder cancer. This lethal infection rate of 3% compares with a rate of 11% in all nondiabetic recipients who have follow-up for 21 months. The 3-year actuarial survival of the PTD group is 75%, which compares favorably with the survival of nondiabetic patients. PTD cannot be predicted by sex, age, or human leukocyte type before transplantation, and it does not significantly increase the incidence of mortality or serious infection.

Coronary artery fistula in the heart transplant patient. A potential complication of endomyocardial biopsy

All follow-up annual cardiac catheterizations performed on recipients of orthotopic heart transplant were reviewed, and 14 patients with coronary artery fistula were identified. The prevalence (8.0%, 14 of 176 patients) was strikingly higher than that for patients without transplant (0.2%) who underwent routine cardiac catheterization. These 14 patients had 21 coronary artery fistulas: single in nine and multiple in five patients. Fifty-two percent arose from the right, 43% from the left anterior descending, and 5% from the circumflex coronary artery. All drained into the right ventricle. Four patients underwent oximetric evaluation, and left-to-right shunting was not detectable. No patient had symptoms attributable to the fistula. Hemodynamic measurements were similar to those of a control group of 28 age- and sex-matched recipients of heart transplant without coronary artery fistula; however, the cardiac index (p = 0.02) and pulmonary artery oxygen saturation (p = 0.03) were significantly higher, and the arteriovenous oxygen difference (p = 0.01) was significantly lower in the group with coronary artery fistula. The histologic features of rejection, large arterioles, or epicardial fat on any biopsy specimen predating coronary artery fistula diagnosis were not associated with the development of the fistula when the two groups were compared. Nine patients (11 coronary artery fistulas) had follow-up studies performed, and three fistulas were larger, three were unchanged, two were smaller, and three had resolved. No complications of coronary artery fistula developed during a mean follow-up of 28 months (range, 12-42 months).(ABSTRACT TRUNCATED AT 250 WORDS)

The artificial heart: infection-related morbidity and its effect on transplantation

Between October, 1985, and September, 1987, a total of 195 patients received cardiac allografts and 15 candidates required mechanical support with the Jarvik-7 total artificial heart. Seven of the 15 died within 60 days of total artificial heart implant. There have been no late deaths, and survivors are unrestricted. Six of 7 deaths were related to infection (mediastinitis, 5; pneumonia and sepsis, 1), and the remaining 1 was due to failure of the transplanted heart. Respiratory tract infection occurred in each of the recipients who died with infection, and the same organisms appeared to be related to subsequent mediastinitis in 3 patients (Serratia marcescens, 2; Pseudomonas, 1) and caused fatal sepsis in another (Enterobacter aerogenes, Candida albicans). One patient died with pneumonia and sepsis prior to transplantation, and another succumbed with mediastinal infection known to be present before transplantation.

Biomechanics of the arterial wall under simulated flow conditions

A perfusion apparatus is employed to reproduce quantifiable pulsatile hemodynamics within freshly excised canine carotid arteries. From measurements of pulsatile intraluminal and transmural pressure and the dynamic radial motion of the vessel wall, calculations are made of the vascular incremental modulus of elasticity and hoop, axial, and radial wall stresses. The results of this investigation suggest that an increase in transmural pressure from 120/80 to 240/120 mmHg produces a marked elevation in incremental modulus and arterial wall stress. These parameters are reduced when transmural pressure is lowered while maintaining intraluminal pressure at physiologic values.

Role of the antibody to vascular endothelial cells in hyperacute rejection in patients undergoing cardiac transplantation

Traditionally, the human lymphocyte antigens have been considered to be the major barrier to successful transplantation, and lymphocytes have been used as the target cell in evaluating histocompatibility. The presence in the serum of recipients of preformed antibodies, cytotoxic to donors lymphocytes, is associated with a high probability of hyperacute rejection. We identified 11 patients in whom, despite a compatible direct lymphocytotoxic cross-match, acute failure of the cardiac homograft was associated with histologic and immunologic findings consistent with hyperacute rejection. Direct immunofluorescence and immunohistochemical staining showed the presence of antibodies on the surface of vascular endothelial cells in each of these 11 patients. The serum of these recipients was found to contain antibodies against a panel of endothelial cells. In contrast, cytotoxic antibodies to vascular endothelial cells were not present in a control group of 18 heart transplant recipients who did not experience hyperacute rejection. Thus the presence of antibodies against vascular endothelial cells seems to be related to hyperacute rejection of the cardiac allograft.

Cardiac transplantation: improved quality of survival with a modified immunosuppressive protocol

The effects on renal function on two different immunosuppressive protocols were evaluated retrospectively in two subsequent groups of heart transplant recipients. In group I, cyclosporine was given before the procedure at a loading dose of 17.5 mg/kg and then continued after the procedure to keep a whole blood level about 1000 ng/ml. In group II, cyclosporine was started only after the procedure at a lower dosage and was complemented by azathioprine, which was used for the first postoperative week. Group II showed a better perioperative renal function as determined by serum blood urea nitrogen and serum creatinine levels. Group II also showed a significant decrease of chronic nephrotoxicity secondary to long-term therapy with cyclosporine. Despite this improvement in late renal function, group II still shows a slow rise in serum creatinine. We think that even these lower dosages of cyclosporine can cause chronic nephrotoxicity and that further modification of the immunosuppressive regimen is required to completely abolish this toxic side effect.

Hemodynamics and the vascular endothelial cytoskeleton

Although there is considerable evidence to suggest that hemodynamics play an important role in vascular disease processes, the exact mechanisms are unknown. With this in mind, we have designed a pulsatile perfusion apparatus which reproducibly delivers pulsatile hemodynamics upon freshly excised canine carotid arteries in vitro. Quantifiable simulations included normotension with normal or lowered flow rates (120/80 mmHg, 120 and 40 ml/min), normotension with lowered or elevated transmural pressures (40-170 mmHg), and elevated pulse pressure (120 and 80 mmHg) with normal (150 ml/min) or elevated rates of flow (300 and 270 ml/min). Arterial biomechanical stresses and cellular behaviors were characterized biochemically and morphologically under all these stimulations which continued for 2-24 h. We found that increased pulse pressure alone had little effect on the total amount of radiolabeled [4-14C]cholesterol present within the medial compartment. However, normotension when coupled with altered transmural pressure yielded a three- to fourfold increase. Combinations of increased pulse pressure and flow potentiated cholesterol uptake by a factor of 10 when compared with normotension control values. Simulations that enhanced carotid arterial cholesterol uptake also influenced the endothelial cytoskeletal array of actin. Stress fibers were not present within the carotid endothelial cells of either the sham controls or the normotension and increased pulse pressure (normal flow) simulations. Endothelial cells lining carotids exposed to elevations in flow or those present within vessels perfused as per simulation b above assembled stress fibers (x = 4 and 10 per cell, respectively) within the time course of these studies. When endothelial cells were subjected to hemodynamic conditions that potentiated maximally cholesterol transport, no diffuse or stress fiber staining could be seen, but the cortical array of actin was intact. These results suggest that those biomechanical stresses that alter endothelial permeability and intimal integrity may do so via cytoskeletal actin signaling.

Heterotopic cardiac transplantation: current status

Heterotopic cardiac transplantation first introduced by Bernard in 1974 currently is rarely used as the procedure of choice when orthotopic cardiac transplantation can be considered. Specific indications for heterotopic cardiac transplantation include elevation of pulmonary vascular resistance and availability of a small or poorly functioning donor organ for a mortally ill recipient. Most cardiac transplant centers have abandoned its routine use because the recipient's diseased and poorly functioning heart remains as a potential source for embolism, infection, and continued angina, because the operative procedure is more complicated. Pulmonary complications are common due to compressive atelectasis of the right lung. Experience indicates that the heterotopic procedure is useful for those selected individuals in whom the orthotopic procedure is not appropriate and that rates of survival are nearly equal.

Temporary use of the Jarvik-7 total artificial heart before transplantation

Between October 24, 1985, and July 31, 1986, the Jarvik-7 total artificial heart was implanted into six moribund patients in an attempt to test its potential as a bridge from almost certain death to cardiac transplantation. Four of these patients are now well and at home after implantation of the device and subsequent cardiac transplantation. Before transplantation, one patient died with sepsis and multiorgan failure that preceded implantation of the artificial heart. Another patient died with acute rejection 60 days after cardiac transplantation. Fifty-two days of total mechanical support with the artificial heart were accumulated in these six patients, and although the device worked flawlessly and no clinically apparent thromboembolic events occurred, each artificial heart contained areas of macroscopic aggregations of platelets and thrombi. The results of this trial indicate that in properly selected cases, direct benefit to the patient can be obtained when the Jarvik-7 artificial heart is used as a bridge to transplantation.

Effect of variations in pressure and flow on the geometry of isolated canine carotid arteries

A study is described in which the effects of hemodynamics on arterial geometry are investigated in vitro. A novel perfusion apparatus is employed to deliver pulsatile flow through excised canine carotid arteries under carefully controlled conditions. Data of perfused vessel diameter and arterial wall thickness are derived from the radial displacement of the pulsating vessel as measured using a scanning laser micrometer whose accuracy is determined to be 0.0125 mm (0.0005 in). The results of 30 perfusion experiments suggest that the hemodynamic variables of transmural pressure, pulse pressure and flow rate influence vessel size and radial strain. The physiologic implications of these findings are discussed.

Early function of cardiac homografts: relationship to hemodynamics in the donor and length of the ischemic period

Twenty-four of 124 heart transplant recipients in our study group died in the perioperative period. In five patients the cause of death was unknown even after postmortem examination. The possibility that the cause of death was due either to poor donor selection or poor preservation of the donor heart was evaluated by reviewing the length of ischemic time of the cardiac homografts and the need for inotropic support in the donors before the hearts were harvested. Results of our retrospective analysis indicate that inotropic support in the form of 2 to 10 micrograms/kg/min dopamine and an ischemic time of up to 4 hr do not influence the early survival of heart transplant recipients.

Cardiac transplantation. Emerging from an experiment to a service

Cardiac transplantation was resumed at the University Health Center of Pittsburgh in 1980 after a hiatus of 12 years. Prior to April 15, 1986, 270 hearts had been transplanted. Participants have been forced to reorder personal, professional, and institutional commitments to adapt to new demands of pre- and post-operative care and to develop flexibility in the operative scheduling of routine cardiac surgical cases. The actuarial survival has been 78, 69, and 64% at 1, 2, and 3 years. Much has been learned about evolving immunosuppression based on cyclosporine and of the allogenic response. An increasing proportion of recipients are mortally ill (54%), and for these urgent patients the wait for a donor organ continues to lengthen. The cardiac surgeon performing transplantations will need to grow with allied developments in xenotransplantation and mechanical cardiac support devices in order to keep pace with his evolving specialty.

Use of the total artificial heart as an interim device: initial experience in Pittsburgh with four patients

The experimental use of the total artificial heart as an interim device before heart transplantation has demonstrated its potential usefulness. Once again there has been a reaffirmation of the basic principle in transplantation that careful selection of patients is a prerequisite for a high likelihood of success. Our experience suggests that advanced degrees of renal failure and liver dysfunction are not likely to be associated with a consistently useful interim support. Although our numbers of patients are quite small, we continue to be concerned by what appears to be the tendency for the development of severe thrombocytopenia not resulting from the use of heparin. Studies of platelet kinetics and deposition are planned for the future. Although no recipient has had direct evidence of thromboembolic events, systemic anticoagulation with heparin has been aggressively applied, and bleeding complications have been common. All Jarvik-7 hearts on which autopsies have been performed have demonstrated grossly evident platelet fibrin thrombi, especially around the inlet and outlet valve housings. It has not been our purpose to investigate the relative role for univentricular or biventricular assist. It is likely that a number of our patients might have benefited from left ventricular assistance alone. It would appear that additional patients are needed before strong conclusions can be formed regarding the potential benefits and risks of the current Jarvik-7 device or any total artificial heart as an interim method of support before heart transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Morbidity and mortality in mitral valve surgery

To develop strategies for the management of high-risk patients, contemporary risk factors for operative mortality and postoperative ventricular dysfunction were identified in 214 patients undergoing mitral valve surgery in 1982 and 1983. Thirty-eight preoperative and perioperative variables were prospectively collected and analyzed by univariate and multivariate statistics. The overall mortality was 4.6% and the incidence of postoperative low-output syndrome (LOS) was 18.7%. Forty-seven patients with coronary artery disease (CAD) had a higher mortality and incidence of LOS (as evidenced by the need for inotropic drugs or counterpulsation to maintain blood pressure) (those with CAD 15% mortality, 40% LOS; those without CAD 2% mortality, 13% LOS; p less than .05). The presence of unstable angina and ischemic mitral regurgitation further increased the risk. Age was also a predictor of outcome. Patients who died or had LOS were older (those who died, 65 +/- 7 years, those with LOS, 58 +/- 11 years) than patients who survived and did not have postoperative dysfunction (those who survived, 53 +/- 11; those with no LOS, 53 +/- 11; p less than .01). Mitral regurgitation was associated with a higher (p less than .05) mortality and incidence of LOS (mortality 10.5%, LOS 36%; n = 76) than was mitral stenosis (mortality 0%, LOS 4%; n = 74) or mixed lesions (mortality 3%, LOS 15%; n = 64). In patients without CAD, mitral regurgitation remained a significant predictor of mortality and ventricular dysfunction.(ABSTRACT TRUNCATED AT 250 WORDS)

Subarachnoid hemorrhage due to a spinal cord hemangioblastoma: case report

A case of solitary spinal hemangioblastoma with spontaneous subarachnoid hemorrhage is presented. There was no features to distinguish the subarachnoid hemorrhage in this case from that due to an intracranial lesion. However, mild sensory symptoms involving the left arm and leg had preceded the hemorrhage by several months. The lesion was detected by cerebral angiography and computed tomographic scanning, and the diagnosis was confirmed at operation. A small syrinx was noted, and the lesion was totally removed without causing any deficit, despite its origin from the dorsum of the spinal cord. The tumor contained a false aneurysm, which had been visualized angiographically.