Making a difference: 5 years of Cardiac Surgery Intersociety Alliance (CSIA).

Informed by the almost unimaginable unmet need for cardiac surgery in the developing regions of the world, leading surgeons, cardiologists, editors in chief of the major cardiothoracic journals as well as representatives of medical industry and government convened in December 2017 to address this unacceptable disparity in access to care. The ensuing "Cape Town Declaration" constituted a clarion call to cardiac surgical societies to jointly advocate the strengthening of sustainable, local cardiac surgical capacity in the developing world. The Cardiac Surgery Intersociety Alliance (CSIA) was thus created, comprising The Society of Thoracic Surgeons (STS), the American Association for Thoracic Surgery (AATS), the Asian Society for Cardiovascular and Thoracic Surgery (ASCVTS), the European Association for Cardio-Thoracic Surgery (EACTS) and the World Heart Federation (WHF). The guiding principle was advocacy for sustainable cardiac surgical capacity in low-income countries. As a first step, a global needs assessment confirmed rheumatic heart disease as the overwhelming pathology requiring cardiac surgery in these regions. Subsequently, CSIA published a request for proposals to support fledgling programmes that could demonstrate the backing by their governments and health care institution. Out of 11 applicants, and following an evaluation of the sites, including site visits to the 3 finalists, Mozambique and Rwanda were selected as the first Pilot Sites. Subsequently, a mentorship and training agreement was completed between Mozambique and the University of Cape Town, a middle-income country with a comparable burden of rheumatic heart disease. The agreement entails regular video calls between the heart teams, targeted training across all aspects of cardiac surgery, as well as on-site presence of mentoring teams for complex cases with the strict observance of 'assisting only'. In Rwanda, Team Heart, a US and Rwanda-based non-governmental organization (NGO) that has been performing cardiac surgery in Rwanda and helping to train the cardiac surgery workforce since 2008, has agreed to continue providing mentorship for the local team and to assist in the establishment of independent cardiac surgery with all that entails. This involves intermittent virtual conferences between Rwandan and US cardiologists for surgical case selection. Five years after CSIA was founded, its 'Seal of Approval' for the sustainability of endorsed programmes in Mozambique and Rwanda has resulted in higher case numbers, a stronger government commitment, significant upgrades of infrastructure, the nurturing of generous consumable donations by industry and the commencement of negotiations with global donors for major grants. Extending the CSIA Seal to additional deserving programmes could further align the international cardiac surgical community with the principle of local cardiac surgery capacity-building in developing countries.

Making a difference: 5 years of Cardiac Surgery Intersociety Alliance (CSIA).

Informed by the almost unimaginable unmet need for cardiac surgery in the developing regions of the world, leading surgeons, cardiologists, editors in chief of the major cardiothoracic journals as well as representatives of medical industry and government convened in December 2017 to address this unacceptable disparity in access to care. The ensuing "Cape Town Declaration" constituted a clarion call to cardiac surgical societies to jointly advocate the strengthening of sustainable, local cardiac surgical capacity in the developing world. The Cardiac Surgery Intersociety Alliance (CSIA) was thus created, comprising The Society of Thoracic Surgeons (STS), the American Association for Thoracic Surgery (AATS), the Asian Society for Cardiovascular and Thoracic Surgery (ASCVTS), the European Association for Cardio-Thoracic Surgery (EACTS) and the World Heart Federation (WHF). The guiding principle was advocacy for sustainable cardiac surgical capacity in low-income countries. As a first step, a global needs assessment confirmed rheumatic heart disease as the overwhelming pathology requiring cardiac surgery in these regions. Subsequently, CSIA published a request for proposals to support fledgling programs that could demonstrate the backing by their governments and health care institution. Out of 11 applicants, and following an evaluation of the sites, including site visits to the 3 finalists, Mozambique and Rwanda were selected as the first Pilot Sites. Subsequently, a mentorship and training agreement was completed between Mozambique and the University of Cape Town, a middle-income country with a comparable burden of rheumatic heart disease. The agreement entails regular video calls between the heart teams, targeted training across all aspects of cardiac surgery, as well as on-site presence of mentoring teams for complex cases with the strict observance of "assisting only." In Rwanda, Team Heart, a US and Rwanda-based nongovernmental organization (NGO) that has been performing cardiac surgery in Rwanda and helping to train the cardiac surgery workforce since 2008, has agreed to continue providing mentorship for the local team and to assist in the establishment of independent cardiac surgery with all that entails. This involves intermittent virtual conferences between Rwandan and US cardiologists for surgical case selection. Five years after CSIA was founded, its "Seal of Approval" for the sustainability of endorsed programs in Mozambique and Rwanda has resulted in higher case numbers, a stronger government commitment, significant upgrades of infrastructure, the nurturing of generous consumable donations by industry and the commencement of negotiations with global donors for major grants. Extending the CSIA Seal to additional deserving programs could further align the international cardiac surgical community with the principle of local cardiac surgery capacity-building in developing countries.

Making a Difference: 5 Years of Cardiac Surgery Intersociety Alliance (CSIA).

Informed by the almost unimaginable unmet need for cardiac surgery in the developing regions of the world, leading surgeons, cardiologists, editors in chief of the major cardiothoracic journals as well as representatives of medical industry and government convened in December 2017 to address this unacceptable disparity in access to care. The ensuing "Cape Town Declaration" constituted a clarion call to cardiac surgical societies to jointly advocate the strengthening of sustainable, local cardiac surgical capacity in the developing world. The Cardiac Surgery Intersociety Alliance (CSIA) was thus created, comprising The Society of Thoracic Surgeons (STS), the American Association for Thoracic Surgery (AATS), the Asian Society for Cardiovascular and Thoracic Surgery (ASCVTS), the European Association for Cardio-Thoracic Surgery (EACTS) and the World Heart Federation (WHF). The guiding principle was advocacy for sustainable cardiac surgical capacity in low-income countries. As a first step, a global needs assessment confirmed rheumatic heart disease as the overwhelming pathology requiring cardiac surgery in these regions. Subsequently, CSIA published a request for proposals to support fledgling programs that could demonstrate the backing by their governments and health care institution. Out of 11 applicants, and following an evaluation of the sites, including site visits to the 3 finalists, Mozambique and Rwanda were selected as the first Pilot Sites. Subsequently, a mentorship and training agreement was completed between Mozambique and the University of Cape Town, a middle-income country with a comparable burden of rheumatic heart disease. The agreement entails regular video calls between the heart teams, targeted training across all aspects of cardiac surgery, as well as on-site presence of mentoring teams for complex cases with the strict observance of "assisting only." In Rwanda, Team Heart, a US and Rwanda-based non-governmental organization (NGO) that has been performing cardiac surgery in Rwanda and helping to train the cardiac surgery workforce since 2008, has agreed to continue providing mentorship for the local team and to assist in the establishment of independent cardiac surgery with all that entails. This involves intermittent virtual conferences between Rwandan and US cardiologists for surgical case selection. Five years after CSIA was founded, its "Seal of Approval" for the sustainability of endorsed programs in Mozambique and Rwanda has resulted in higher case numbers, a stronger government commitment, significant upgrades of infrastructure, the nurturing of generous consumable donations by industry and the commencement of negotiations with global donors for major grants. Extending the CSIA Seal to additional deserving programs could further align the international cardiac surgical community with the principle of local cardiac surgery capacity-building in developing countries.

Making a difference: 5 years of Cardiac Surgery Intersociety Alliance (CSIA).

SUMMARY: Informed by the almost unimaginable unmet need for cardiac surgery in the developing regions of the world, leading surgeons, cardiologists, editors in chief of the major cardiothoracic journals as well as representatives of medical industry and government convened in December 2017 to address this unacceptable disparity in access to care. The ensuing "Cape Town Declaration" constituted a clarion call to cardiac surgical societies to jointly advocate the strengthening of sustainable, local cardiac surgical capacity in the developing world. The Cardiac Surgery Intersociety Alliance (CSIA) was thus created, comprising The Society of Thoracic Surgeons (STS), the American Association for Thoracic Surgery (AATS), the Asian Society for Cardiovascular and Thoracic Surgery (ASCVTS), the European Association for Cardio-Thoracic Surgery (EACTS) and the World Heart Federation (WHF). The guiding principle was advocacy for sustainable cardiac surgical capacity in low-income countries. As a first step, a global needs assessment confirmed rheumatic heart disease as the overwhelming pathology requiring cardiac surgery in these regions. Subsequently, CSIA published a request for proposals to support fledgling programmes that could demonstrate the backing by their governments and health care institution. Out of 11 applicants, and following an evaluation of the sites, including site visits to the 3 finalists, Mozambique and Rwanda were selected as the first Pilot Sites. Subsequently, a mentorship and training agreement was completed between Mozambique and the University of Cape Town, a middle-income country with a comparable burden of rheumatic heart disease. The agreement entails regular video calls between the heart teams, targeted training across all aspects of cardiac surgery, as well as on-site presence of mentoring teams for complex cases with the strict observance of 'assisting only'. In Rwanda, Team Heart, a US and Rwanda-based non-governmental organization (NGO) that has been performing cardiac surgery in Rwanda and helping to train the cardiac surgery workforce since 2008, has agreed to continue providing mentorship for the local team and to assist in the establishment of independent cardiac surgery with all that entails. This involves intermittent virtual conferences between Rwandan and US cardiologists for surgical case selection. Five years after CSIA was founded, it's 'Seal of Approval' for the sustainability of endorsed programmes in Mozambique and Rwanda has resulted in higher case numbers, a stronger government commitment, significant upgrades of infrastructure, the nurturing of generous consumable donations by industry and the commencement of negotiations with global donors for major grants. Extending the CSIA Seal to additional deserving programmes could further align the international cardiac surgical community with the principle of local cardiac surgery capacity-building in developing countries.

Real-time visualization and quantification of retrograde cardioplegia delivery using near infrared fluorescent imaging.

BACKGROUND AND AIM: Homogeneous delivery of cardioplegia is essential for myocardial protection during cardiac surgery. Presently, there exist no established methods to quantitatively assess cardioplegia distribution intraoperatively and determine when retrograde cardioplegia is required. In this study, we evaluate the feasibility of near infrared (NIR) imaging for real-time visualization of cardioplegia distribution in a porcine model. METHODS: A portable, intraoperative, real-time NIR imaging system was utilized. NIR fluorescent cardioplegia solution was developed by incorporating indocyanine green (ICG) into crystalloid cardioplegia solution. Real-time NIR imaging was performed while the fluorescent cardioplegia solution was infused via the retrograde route in five ex vivo normal porcine hearts and in five ex vivo porcine hearts status post left anterior descending (LAD) coronary artery ligation. Horizontal cross-sections of the hearts were obtained at proximal, middle, and distal LAD levels. Videodensitometry was performed to quantify distribution of fluorophore content. RESULTS: The progressive distribution of cardioplegia was clearly visualized with NIR imaging. Complete visualization of retrograde distribution occurred within 4 minutes of infusion. Videodensitometry revealed retrograde cardioplegia, primarily distributed to the left ventricle (LV) and anterior septum. In hearts with LAD ligation, antegrade cardioplegia did not distribute to the anterior LV. This deficiency was compensated for with retrograde cardioplegia supplementation. CONCLUSIONS: Incorporation of ICG into cardioplegia allows real-time visualization of cardioplegia delivery via NIR imaging. This technology may prove useful in guiding intraoperative decisions pertaining to when retrograde cardioplegia is mandated.

The Cape Town Declaration on Access to Cardiac Surgery in the Developing World.

Twelve years after cardiologists and cardiac surgeons from all over the world issued the 'Drakensberg Declaration on the Control of Rheumatic Fever and Rheumatic Heart Disease in Africa', calling on the world community to address the prevention and treatment of rheumatic heart disease (RHD) through improving living conditions, to develop pilot programmes at selected sites for control of rheumatic fever and RHD, and to periodically review progress made and challenges that remain, RHD still accounts for a major proportion of cardiovascular diseases in children and young adults in low- and middle-income countries, where more than 80% of the world population live. Globally equal in prevalence to human immunodeficiency virus infection, RHD affects 33 million people worldwide. Prevention efforts have been important but have failed to eradicate the disease. At the present time, the only effective treatment for symptomatic RHD is open heart surgery, yet that life-saving cardiac surgery is woefully absent in many endemic regions. In this declaration, we propose a framework structure to create a co-ordinated and transparent international alliance to address this inequality.

Dilated cardiomyopathy in infants and children.

The outcome of medical treatment of dilated cardiomyopathy in infants and children was reviewed to develop a predictive index for selection of patients likely to benefit from cardiac transplantation. The clinical findings, laboratory investigations, treatment and outcome of 20 patients (Group 1) less than 2 years of age at presentation and 12 patients (Group 2) greater than 2 years of age at onset were compared. Of 20 Group 1 patients, 5 (25%) died. Available autopsies (four patients) showed endocardial fibroelastosis. Of 15 survivors, 10 showed improvement in cardiac status and 5 remained unchanged. Ninety-three percent of survivors had dilated cardiomyopathy consistent with endocardial fibroelastosis by angiocardiography. All 12 Group 2 patients died. In addition to age at presentation and poor outcome, Group 2 differed from Group 1 in having a higher incidence of other family members with cardiomyopathy, more significant rhythm disturbances at presentation and a more rapid course to death. Risk factors of poor outcome in both groups included persistent cardiomegaly and the development of significant arrhythmias by Holter electrocardiographic monitoring. Cardiac transplantation is recommended for children with dilated cardiomyopathy presenting after age 2 years who survive 1 month. Those patients less than 2 years old at presentation whose condition has not improved after 1 year and who have persistent cardiomegaly or complex ventricular arrhythmias may also benefit from transplantation.

Trends in patient selection for heart transplantation.

OBJECTIVES: The purpose of this study was to review specific outcomes of patient referrals and the utility of selection criteria for heart transplantation at a single transplant center and to assess important trends over a 5-year period. BACKGROUND: Although patient selection criteria are important for the clinical success of heart transplantation and the optimal utilization of the limited supply of donor organs, there are few data regarding actual outcomes and whether selection criteria are facilitating the identification of the most appropriate patients. METHODS: We retrospectively reviewed 511 consecutive referrals of adult patients with heart failure from January 1, 1987 to December 31, 1991. Patients were followed up to one of five end points: 1) acceptance onto the transplant waiting list, 2) rejection from the transplant waiting list, 3) death, 4) referral to another program, and 5) still pending evaluation. RESULTS: Of the 511 referred patients, 221 (43%) were accepted onto the waiting list, 222 (43%) were rejected, 39 (8%) died before the evaluation was completed, 15 (3%) were referred to another program and 14 (3%) are still pending evaluation. The rates for acceptance and rejection each year ranged between 30% and 51% and there were no consistent trends in the acceptance/rejection ratio from 1987 to 1991. Of the 221 patients accepted onto the waiting list, 115 (52%) underwent transplantation, 50 (22%) died, 12 (5%) were removed from the list because of clinical improvement, 9 (4%) were referred to another program and 35 (16%) are still on the waiting list. The continuing shortage of donor organs resulted in a marked increase in the size of the waiting list from 12.6 patients in 1987 to 36.5 in 1991, as well as a marked increase in the time on the waiting list before transplantation. Over 5 years, 50 patients were considered "too well" for transplantation (23% of all rejections). Of these 50 patients, 43 (86%) are alive and 7 were lost to follow-up during a mean period of 28.6 months (range 4 to 62). All 12 patients who were taken off the active transplant list because of improvement in symptoms, ejection fraction or peak exercise oxygen consumption are alive with a mean follow-up period of 27.7 months (range 11 to 61). CONCLUSIONS: These data confirm the fact that transplant referrals are a selected group of patients with a high mortality rate, as 8% died before the evaluation could be completed and 22% died while waiting for a suitable donor organ. Furthermore, patient selection criteria are able to identify a small subset of patients with a low mortality risk as patients who were rejected because they were too well or taken off the list for clinical improvement have a reasonably good prognosis.

Stimulation of gastrin secretion in the pig by parathyroid hormone and its inhibition by thyrocalcitonin.

Gastrin secretion was studied in 16 young anesthetized pigs weighing 14-26 kg. Test substances were infused (0.1 ml/min x 10-20 min) directly into the gastric antrum via a catheter in the right gastroepiploic artery. Samples were collected from a catheter in the right gastroepiploic vein and plasma gastrin was measured by radiommunoassay. The following results were observed: 1) basal gastrin in antral venous blood was 10-5 times that in peripheral blood (620+/-222 pg/ml vs. 41+/-10 pg/ml, 2) native bovine parathyroid hormone (PTH) and synthetic human 1-34 PTH (0.02-4U/min) produced rapid (within 10-30 min) and pronounced (approximately 10-fold) increases in gastrin release with no increase in plasma calcium and, in several animals, in the face of a falling plasma calcium concentration, 3) neither acute thyroidectomy nor infusion of porcine thyrocalcitonin (TCT), 0.5-2.5 U/min) consistently altered basal gastrin secretion (N=3-6), and 4) infusion of TCT (0.5 U/min)along with PTH (2U/min) significantly suppressed the 10-11-fold increase in gastrin release observed when PTH subsequently was infused alone in each pig (N=6). The results demonstrate that PTH can stimulate gastrin secretion in the pig and that TCT can suppress this effect.

Atypical adrenal insufficiency with failure of the pituitary feedback receptor. A case with associated diabetes mellitus and selective IgA deficiency with steatorrhea.

A 59 year old woman with insulin-dependent diabetes mellitus and chronic diarrhea was found to have mild steatorrhea, selective plasma IgA deficiency and adrenal insufficiency. Significant adrenal secretion of corticosteroids resulted only after prolonged stimulation with large doses of exogenous ACTH. Plasma ACTH levels were not elevated during clinical adrenal insufficiency or after metyrapone administration but did respond normally to vasopressin and insulin-induced hypoglycemia. These studies were interpreted as showing both primary adrenal insufficiency and impaired pituitary reserve for ACTH secretion in response to the feedback stimulus. No deficiency was found in secretion of other pituitary tropic hormones. Jejunal biopsy showed a lack of IgA-containing plasma cells. With cortisone replacement, diarrhea subsided and a malabsorption pattern on a film of the small bowel was no longer seen. IgA deficiency has been noted frequently with steatorrhea but rarely with diabetes and only once previously with adrenal insufficiency.

Lung transplant pathology. A comparative study of pulmonary acute rejection and cytomegaloviral infection.

This article describes a comparative study performed to determine the histologic features of pulmonary rejection and cytomegaloviral (CMV) infection following lung transplantation. Rejection was defined clinically by findings of new pulmonary symptoms or radiographic changes or decreased oxygenation in the absence of documented infection in patients who were treated for rejection and improved. These patients also had negative CMV cultures. CMV infection was studied in a group of non-lung and non-bone marrow transplant patients and was defined by the presence of characteristic nuclear inclusions in lung biopsies. Ten rejection biopsies and nine CMV biopsies were examined. No histologic feature was unique to rejection, however; perivascular lymphocytic infiltrates occurred more frequently and more intensely in rejection than in CMV infection (p = 0.0029). Endothelialitis also occurred more frequently in rejection (p = 0.0331), but it was always seen in association with perivascular lymphocytic inflammation. In rejection, the inflammatory infiltrate was primarily perivascular, with extension into the interstitium in several cases. In contrast, CMV infection was characterized predominantly by interstitial inflammation with involvement of associated vessels. We conclude that although overlapping features are present in both processes, pulmonary rejection can be distinguished from CMV infection on the basis of histology.

Selective IgM depletion prolongs organ survival in an ex vivo model of pig-to-human xenotransplantation.

In the pig-to-primate model, xenograft hyperacute rejection (HAR) is mediated by antibody and complement. Previous studies have implicated xenoreactive IgM natural antibody (nAb) as the predominant immunoglobulin involved in HAR. To further evaluate the role of IgM, we selectively reduced IgM levels in human blood, without changing IgG and IgA levels, and then used this blood to perfuse porcine hearts ex vivo. Specific IgM depletion was accomplished with an immunoabsorption column containing sheep anti-human IgM (mu-chain specific) conjugated to Sepharose beads. Human blood was separated into plasma and cellular components. For control experiments, those components were unmodified and recombined in the perfusion system. For experiments with IgM reduced blood, the plasma was passed through the IgM column. Immunoabsorption resulted in approximately 90% reduction in xenoreactive IgM levels, as measured by ELISA. Porcine hearts perfused with unmodified human blood survived 25 +/- 5.6 min (n=5). Porcine hearts perfused with human blood containing reduced levels of IgM survived 229 +/- 45.2 min (n=4; P<0.01). Organ survival was negatively associated with xenoreactive IgM nAb levels measured immediately before perfusion (r=-0.83; P=0.01), and not with IgG nAb levels (r=-0.21; P=0.62). The ability of plasma from IgM-depleted blood to elicit complement activation, measured by iC3b binding to porcine aortic endothelial cells in vitro, was also strongly associated with IgM xenoreactive nAb levels (r=0.92; P<0.0001). Control hearts perfused with unmodified human blood showed typical widespread histologic features of HAR, while porcine hearts perfused with IgM-reduced blood demonstrated milder and less uniform changes. Immunopathological analysis of heart tissues obtained at the completion of each study showed similar deposition of IgG between groups but markedly less IgM, C3, C4, and C9 in the IgM reduction group. These results suggest that selective IgM reduction delays HAR with prolongation of survival and that xenoreactive IgM may be the predominant immunoglobulin involved in HAR in the pig-to-human combination.

Are multiple immunopathogenetic events occurring during the development of obliterative bronchiolitis and acute rejection?

The primed lymphocyte test (PLT) has been used to detect donor antigen-specific reactivity of bronchoalveolar lavage (BAL) lymphocytes associated with acute lung rejection and obliterative bronchiolitis (OB). To identify more precisely the immunopathogenetic events related to these processes, we have determined the PLT alloreactivity of 162 BAL specimens from 40 recipients as being directed against individual class I or class II antigens. We used selected homozygous typing cells representing the specific HLA class I and II antigens expressed by the recipient and donor cells. Our previous studies demonstrated a predominant CD8+ cell population mediating class I donor antigen-specific reactivity, correlating with OB in 3 out of 3 recipients tested, and a predominant CD4+ cell population mediating class II donor antigen-specific reactivity, correlating with acute rejection episodes in 13 out of 15 recipients tested. The obstructive airway disease OB, which is frequently fatal, is identified histologically by the presence of small airway inflammation and fibrosis of the lamina propria and lumen, and is characterized clinically by rapidly progressive airflow obstruction. However, a subgroup of patients with histologically proven OB demonstrates stabilization or only minimal progression of airflow limitation after augmentation of their immunosuppressive regimen, usually with high-dose methylprednisolone. To further characterize this subgroup, we tested the BAL-derived lymphocytes from 4 of these patients and observed PLT reactivity that correlated with the class II antigens of the donor, in contrast to the predominant donor class I antigen-specific PLT reactivity of patients with progressive OB. The distinct patterns of PLT reactivity observed for the BAL-derived lymphocytes from patients with the progressive versus the less progressive form of OB suggest that more than one immune process or perhaps different cell targets are involved. Alternatively, these clinical and in vitro findings may represent different stages of the same disease process. Taken together, these results suggest that distinct immunopathogenetic events may be occurring during acute lung rejection and OB.

Sequential measurement of peripheral blood allogeneic microchimerism levels and association with pulmonary function.

We have shown in lung recipients that high levels of peripheral blood allogeneic microchimerism at 12 to 18 months posttransplant correlated with donor antigen-specific hyporeactivity (i.e., decreased proliferative response to donor antigen in MLC while response to 3rd-party cells remains unchanged); both parameters correlated with an obliterative bronchiolitis (OB)-free state. We have expanded these studies to determine any association of sequential microchimerism levels with concomitant clinical events. In this preliminary study of 7 lung recipients, we used limiting-dilution PCR to quantify peripheral blood microchimerism at serial timepoints ranging from 3 to >48 months posttransplant. These levels were compared with a variety of immunologic and clinical parameters: acute rejection, CMV infection, OB, donor antigen-specific hyporeactivity, and pulmonary function. Pulmonary function was measured per the International Society of Heart and Lung Transplantation: "current FEV1/ baseline FEV1" (FEV1: forced expiratory volume in 1 second). Of the clinical parameters, the association between microchimerism and pulmonary function was the most striking. We observed dynamic patterns of peripheral microchimerism, which reflected the general rise and fall of FEV1. In all 7 recipients, chimerism and FEV1 were high very early posttransplant, then dropped at various rates and to various degrees. After its initial decline, microchimerism increased with FEV1 for the 1 hyporesponsive recipient; for the other 6 recipients, both values declined. These results illustrate, for the first time, that the fluctuation of peripheral blood microchimerism levels is associated with the recipient's clinical condition.

Effect of hypothermic pulmonary artery flushing on capillary filtration coefficient.

BACKGROUND: We previously demonstrated that surfactant dilution and inhibition occur immediately after pulmonary artery flushing with hypothermic modified Euro-Collins solution. Consequently, we speculated that increased capillary permeability contributed to these surfactant changes. To test this hypothesis, we evaluated the effects of hypothermic pulmonary artery flushing on the pulmonary capillary filtration coefficient (Kfc), and additionally performed a biochemical analysis of surfactant. METHODS: We used a murine isolated, perfused lung model to measure the pulmonary capillary filtration coefficient and hemodynamic parameters, to determine the wet to dry weight ratio, and to evaluate surfactant by biochemical analysis of lung lavage fluid. We defined three study groups. In group I (controls), we harvested lungs without hypothermic pulmonary artery flushing, and measured Kfc immediately. In group II (in situ flush), we harvested lungs after hypothermic pulmonary artery flushing with modified Euro-Collins solution, and then measured Kfc. Experiments in groups I and II were designed to evaluate persistent changes in Kfc after pulmonary artery flushing. In group III (ex vivo flush), we flushed lungs ex vivo to evaluate transient changes in Kfc during hypothermic pulmonary artery flushing. RESULTS: Groups I and II did not differ significantly in capillary filtration coefficient and hemodynamics. Group II showed significant alterations on biochemical surfactant analysis and a significant increase in wet-to-dry weight ratio, when compared with group I. In group III, we observed a significant transient increase in capillary filtration coefficient during pulmonary artery flushing. CONCLUSIONS: Hypothermic pulmonary artery flushing transiently increases the capillary filtration coefficient, leads to an increase in the wet to dry weight ratio, and induces biochemical surfactant changes. These findings could be explained by the effects of hypothermic modified Euro-Collins solution on pulmonary capillary permeability.

Differentiation of class I- and class II-directed donor-specific alloreactivity in bronchoalveolar lavage lymphocytes from lung transplant recipients.

Previous studies have demonstrated that donor antigen-specific primed-lymphocyte-test (PLT) reactivity of bronchoalveolar lavage lymphocytes is strongly associated with acute pulmonary rejection and with obliterative bronchiolitis (OB); however, a systematic analysis of PLT reactivity as being class I-or II-directed has not been performed. To assess reactivity directed against individual class I or II antigens, we tested a total of 67 BAL-derived lymphocyte samples from 26 recipients for alloreactivity in the PLT, using a pool of allogeneic cells and selected homozygous typing cells (HTCs) representing the HLA class I and II antigens expressed by the recipient and donor cells. The results obtained by PLT were correlated with the clinical status of the recipient with regard to rejection, infection, and OB. In 9 of 10 cases where transbronchial biopsy results were consistent with rejection, donor antigen-specific allogeneic PLT reactivity was observed and, more specifically, could be determined to be directed toward donor class II antigen in 8 of these cases. For 3 of 4 recipients tested chronologically, positive donor antigen-specific PLT reactivity was observed at the time of and 2-3 1/2 months prior to the diagnosis of rejection by transbronchial biopsy. During periods of acute infection, donor antigen-specific PLT reactivity was not observed; instead, non-specific PLT reactivity of BAL-derived cells (i.e., reactivity that did not correlate with any defined HLA antigens) was observed as well as reactivity associated with the self-antigens expressed by the recipients' cells. The PLT reactivity of BAL-derived cells from a recipient diagnosed with OB correlated specifically with one of the disparate donor class I antigens (HLA-B44). In 23 cases, BAL cells were propagated in the presence of autologous cells and rIL-2, thereby allowing for sufficient numbers of cells to test with a panel of 29 HTCs and to analyze for cell surface phenotype. The cultured BAL cells from 4 recipients undergoing a rejection episode demonstrated a predominant CD4+ phenotype consistent with the class II-directed reactivity observed in PLT. However, these results did not demonstrate a phenotype distinctive from the 7 BAL results obtained from 4 quiescent recipients. In marked contrast, the cultured BAL cells obtained from 4 recipients diagnosed with OB demonstrated a predominant CD8+ phenotype, with 60-92% of the cultured cells being CD8+. These results are consistent with the class I-directed reactivity observed in PLT.(ABSTRACT TRUNCATED AT 400 WORDS)

Noninvasive assessment of treatment of cardiac allograft rejection with indium-111-labeled lymphocytes.

We have shown previously that cardiac allograft rejection can be detected noninvasively with gamma scintigraphy after administration of indium-111 (111In)-labeled lymphocytes. To determine whether this technique could be used to monitor salvage immunosuppressive therapy in reversing rejection, 5 dogs were studied after thoracic heterotopic cardiac transplantation. Initial postoperative immunosuppression was maintained with cyclosporine (10-20 mg/kg/day) and prednisone (1 mg/kg/day) for 7 days after transplantation and then discontinued. Scintigraphy after administration of labeled lymphocytes was performed during initial immunosuppression and every 3 days after its termination. Endomyocardial biopsies were obtained on each day scintigraphy was performed. Once scintigraphic criteria for rejection were met (111In-lymphocyte uptake greater than mean +/- 2SD of normal myocardium), animals were treated with high dose methylprednisolone and cyclosporine. Myocardial 111In-lymphocyte activity compared with that in blood was 0.7 +/- 0.8 during initial immunosuppression, increased to 5.7 +/- 3.5 after termination of therapy (P less than 0.01), and diminished with salvage immunosuppressive therapy to 0.5 +/- 0.8 (P = NS compared with native hearts or allografts during initial immunosuppression). Scintigraphy accurately predicted all but one episode of biopsy-documented rejection and accurately detected reversal of rejection during salvage. Thus, scintigraphy with 111In-labeled lymphocytes should facilitate noninvasive monitoring of antirejection therapy in patients.

Immunopathology of hyperacute xenograft rejection in a swine-to-primate model.

Hyperacute rejection is the inevitable consequence of the transplantation of vascularized organs between phylogenetically distant species. The nature of the incompatibility and the pathogenetic mechanisms that lead to hyperacute xenograft rejection are incompletely understood. We investigated these issues by the immunopathological analysis of tissues from swine renal and cardiac xenografts placed in rhesus monkeys. Hyperacute rejection was associated with deposition of recipient IgM and classic but not alternative complement pathway components along endothelial surfaces, the formation of platelet and fibrin thrombi, and the infiltration of neutrophils. In animals from which natural antibody was temporarily depleted by organ perfusion, rejection was observed at 3 days to 5 days posttransplant. The immunopathology of rejection in these tissues revealed focal vascular changes similar to those observed in hyperacute rejection. A xenograft functioning for a prolonged period in a recipient temporarily depleted of circulating natural antibody contained recipient IgM along endothelial surfaces but no evidence for significant deposition of complement, formation of platelet and fibrin thrombi, or infiltration of neutrophils. These results suggest that rhesus IgM contributes significantly to the development of hyperacute rejection in the swine to Rhesus model and that the fixation of complement is a critical factor in the recruitment of the coagulation cascade and platelet aggregation--and possibly in the adherence and infiltration of PMN.

Surfactant dysfunction in lung preservation.

We studied the effect of lung preservation on the surfactant system in rats. Lung surfactant is necessary to maintain normal lung mechanics, and hence normal lung function. We evaluated lung mechanics with pressure-volume (P-V) curves, and analyzed biochemical changes of surfactant in bronchoalveolar lavage (BAL) fluid. Additionally, we determined wet to dry weight ratios (W/D). We defined five study groups. In group I (controls) we harvested lungs without pulmonary artery flushing, then evaluated them immediately. In group II we flushed lungs through the pulmonary artery (PA) with hypothermic modified Euro-Collins solution (mECS), then removed and studied them immediately to determine the consequences of PA flushing alone. In groups III, IV, and V we flushed lungs with mECS, then stored them in normal saline (NS) for 6 hr (group III); in NS for 12 hr (group IV); or in mECS for 12 hr (group V). In groups III, IV, and V we evaluated lungs after storage. All four experimental groups showed significant changes in lung mechanics and surfactant biochemistry, compared with controls. Lungs in groups III, IV, and V showed additional changes in lung mechanics and surfactant biochemistry compared with group II. The W/D in stored lungs (groups III, IV, and V) was significantly higher than in controls and group II. We conclude that lung preservation induces deleterious changes in the surfactant system. Surfactant alterations are evident immediately after pulmonary artery flushing, and increase in severity with storage.

A recombinant soluble chimeric complement inhibitor composed of human CD46 and CD55 reduces acute cardiac tissue injury in models of pig-to-human heart transplantation.

BACKGROUND: Inasmuch as complement plays a critical role in many pathological processes and in xenograft rejection, efficient complement inhibitors are of great interest. Because the membrane-associated complement inhibitors are very effective, recombinant soluble molecules have been generated. METHODS: We tested the efficacy of complement activation blocker-2 (CAB-2), a recombinant soluble chimeric protein derived from human decay accelerating factor (DAF, CD55) and membrane cofactor protein (MCP, CD46), in two models of pig-to-human xenotransplantation in which tissue injury is complement mediated. The in vitro model consisted of porcine aortic endothelial cells and human serum, and the ex vivo model consisted of a porcine heart perfused with human blood. RESULTS: In vitro, addition of CAB-2 to serum inhibited cytotoxicity and the deposition of C4b and iC3b on the endothelial cells. Ex vivo, addition of CAB-2 to human blood prolonged organ survival from 17.3 +/- 6.4 min in controls to 108 +/- 55.6 min with 910 nM (100 microg/ml) CAB-2 and 219.8 +/- 62.7 min with 1820 nM (200 microg/ml) CAB-2. CAB-2 also retarded the onset of increased coronary vascular resistance. The complement activity of the perfusate was reduced by CAB-2, as was the generation of C3a and SC5b-9. The myocardial tissues had similar deposition of IgG, IgM, and Clq; however, CAB-2 reduced the deposition of C3, C4, and C9. Hearts surviving >240 min demonstrated trace to no deposition of C9 and normal histologic architecture. CONCLUSION: These results indicate that CAB-2 can function as an inhibitor of complement activation and markedly reduce tissue injury in models of pig-to-human xenotransplantation and thus may represent a useful therapeutic agent for xenotransplantation and other complement-mediated conditions.