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Biomedical subjects

J Wallwork

Publications and source records attributed to J Wallwork.

At least 109 records · Page 6Linked to original sources
PubMed1995

Clinical experience with a collagen impregnated woven Dacron graft.

Vascular grafts continue to evolve. Recent developments have been aimed at decreasing porosity, increasing strength of prosthesis, increasing ease of handling and suturing and optimising flow characteristics. This study describes results with a recently developed collagen impregnated polyester prosthesis Hemashield Woven Double Velour, which does not require pre-clotting. Between January 1988 and December, 1991 such prostheses were used in 90 patients at Papworth Hospital. Fifty-eight, were used to replace the ascending aorta, 10 for the arch of the aorta and 28 for the descending aorta seven of whom were for coarctation and four for traumatic transections. In 60 cases the underlying disease was a dissected or ruptured aorta requiring emergency operation. There were 66 survivors with X-ray and CT follow-up of 6-52 months. Median blood loss was 630 ml range 380-1800 ml. There was no leakage from any of the grafts during surgery despite full perioperative heparinisation. For emergency/elective operations (N = 60/30) early mortality was 25%/10% (15/3) and late mortality 5%/6.6% (3/2). Of 15 patients who had interposition grafts for Type A dissection CT scans at 5-47 months showed one with chronic dissection proximal to the repair and 11 with persistent distal dissection. There was no evidence of late bleeding, seroma impaired healing or thickened neointima formation. It is concluded that there are no clinical disadvantages associated with collagen impregnation to set against the notable convenience of initial impermeability.

Adult↗
PubMed1994

Heart-lung transplantation in situs inversus and chest wall deformity.

Heart-lung transplantation in the presence of complex congenital heart disease including situs inversus and significant chest wall deformity can be accomplished successfully. However, the postoperative course is apt to be prolonged because of mechanical respiratory problems, which will respond to a protocol of weaning and nutritional supplementation.

Adult↗
PubMed1994

A comparison of the performance of pig hearts perfused with pig or human blood using an ex-vivo working heart model.

The pathophysiology of xenograft hyperacute rejection is still poorly understood although it is believed to involve complement fixation to vascular endothelium, probably as a result of the presence of naturally occurring anti-species antibodies. Hyperacute rejection of pig hearts by human blood was studied in an ex-vivo working heart model. Cardiac performance and immunological reactions occurring in the perfusing blood were studied. Stroke work performed by pig hearts perfused with human blood and their survival (median 47 min: n = 10) was significantly reduced compared to survival (median 158 min: n = 10) and stroke work performed by pig hearts perfused with pig blood. Decomplementation of human blood resulted in improved performance and duration of the action (median survival > 240 min: n = 10) of hearts. Quantitative differences were seen in complement fixation between the groups. Our data demonstrate the central role of complement in the destruction of pig-to-man xenografts.

Animals↗
PubMed1994

Using "unsuitable" hearts for transplantation.

Donor availability is the single most limiting factor in heart transplantation. From a consecutive series of 100 heart donors, there were 21 which fell well outside our minimum criteria on initial inspection: mean arterial pressure (MAP) more than 60 mm Hg, central venous pressure (CVP) less than 12 mm Hg, pulmonary capillary wedge pressure (PCWP) less than 12 mm Hg, left ventricular stroke work index (LVSWI) more than 15 g.m. on inotropes less than 5 mcg/kg per min. Of these 13 out of 21 had a MAP less than 55 mm Hg, 6 out of 21 a CVP more than 15 mm Hg and 2 out of 21 were on inotropes at more than 20 mcg/kg per min. Following full invasive monitoring another 14 donors fell outside our criteria; 5 had a mean LVSWI of 12.4 g.m. and 9 had a mean PCWP of 19.6 mm Hg. Following the institution of our hormone-based pharmacological resuscitation regime 30 of these donors yielded 19 transplantable hearts and 11 transplantable heart-lung blocks. The other five were not used due to left ventricular hypertrophy (2), inotrope dependency (2) and persistent poor function (1). Twenty-five of the 30 recipients of these organs (83.3%) are alive and well, 4-25 months post transplant. Four early deaths occurred; one arrhythmia (heart), one acute respiratory distress syndrome (heart), one cerebrovascular accident (heart lung) and one infection (heart, lung and liver). One death occurred at 90 days from tamponade (heart). Aggressive and focussed donor management has helped us to maintain our levels of transplant activity, without compromising the outcome--a 30-day mortality of 16.2% in 1989, 11.8% in 1990 and 6.8% in 1991.

Blood Pressure↗
PubMed1994

Transmission of hepatitis C virus by organ transplantation in the United Kingdom.

This study employed a second-generation anti-HCV ELISA, and a second-generation recombinant immunoblot assay and hepatitis C virus RNA detection by polymerase chain reaction to investigate the anti-HCV prevalence in 554 British organ donors and the transmission of hepatitis C virus to heart, liver and kidney recipients between 1984 and 1991. Serum samples from six (1.08%) donors were reactive in the second-generation anti-HCV ELISA and four (67%) of these gave positive or indeterminate results in the recombinant immunoblot assay-2. Of the 15 recipients of these organs from hepatitis C virus-confirmed positive/indeterminate donors, 14 (93%) acquired hepatitis C virus infection and seven (47%) had evidence of hepatitis C virus-related liver disease after transplantation and no evidence of blood transfusion-related transmission. Only six of the 15 (40%) recipients had detectable anti-HCV after transplantation, while 12 of 14 (86%) patients tested had hepatitis C virus RNA in their serum detectable by "nested" polymerase chain reaction. These data indicate a very high rate of transmission with a major risk of the development of liver disease. We believe our study supports the testing of all British organ donors for anti-HCV and that organs from anti-HCV-positive patients should not be transplanted unless the recipient has life-threatening disease and there is a donor shortage, when their use may be justified. Since there are time constraints on organ donor testing, which may frequently be done on call during unsocial hours, we would recommend second-generation ELISA as the current screening test of choice.(ABSTRACT TRUNCATED AT 250 WORDS)

Enzyme-Linked Immunosorbent Assay↗
PubMed1994

Risk factors for survival following combined heart-lung transplantation. The first 100 patients.

As the numbers of heart and lung transplant recipients have increased it has become possible to identify major risk factors for early (within 3 months) and later (after 3 months) death after this procedure. For 100 patients receiving organs between April 1984 and February 1991, and followed up until February 1992, patient characteristics, operative details, and early morbidity were assessed for their effects on early and later deaths. Recipient age, sex, and preoperative diagnosis did not have a significant effect on early (within 3 months) or later death. Positive cytomegalovirus antibody status of donor or recipient conferred greater risk of death within 90 days (odds ratio [OR] = 3.24, P = 0.06). Greater than 2 L blood in the first 24 hr after operation (OR = 6.00, P = 0.05), and ventilation for greater than 24 hr (OR = 4.87, P = 0.006) were significant prognostic indicators of early death. After the first 3 months, the main risk factor for death was rejection in the first 3 months (OR = 1.38 per episode, P = 0.008). Early infection in general and CMV infection in particular were associated with a small increase in risk. This study confirms the importance of matching donor and recipient for CMV and shows that difficulties during operation, reflected in postoperative bleeding and ventilation times increased the chance of early death. Later death was associated with early acute rejection. A detrimental effect of infection, including CMV infection, either does not exist, or is too small to be detected in a study of this size.

Actuarial Analysis↗
PubMed1994

Neutrophil elastase and obliterative bronchiolitis.

Bronchoalveolar lavage levels of elastase were assayed to determine the timing and magnitude of elevations in elastase relative to both fibrosis, as indicated by hyaluronate (HA) levels, and decline in FEV1 characteristic of the clinical syndrome of obliterative bronchiolitis (OB). Samples were collected from 48 heart-lung or single lung transplant recipients. Regression analysis was performed and demonstrated that high levels of elastase occurred with active decline in lung function and in association with high levels of HA. This study suggested that intense neutrophil elastase release occurs concurrent with the development of OB and may contribute to the destruction of bronchiolar architecture.

Adolescent↗
PubMed1994

Paediatric incidence of acute rejection and obliterative bronchiolitis: a comparison with adults.

Obliterative bronchiolitis (OB) continues to be a major cause of morbidity and mortality following heart-lung transplantation. We compared the incidence of death from obliterative bronchiolitis in 19 children and 72 adults following heart-lung transplantation at our institutes. The incidence of death from OB at 2 years was 38% for children compared with 17% for adults, this difference was significant (Cox-Mantel Z value = 2.243, P < 0.05). The frequency of acute lung rejection and persistent lung rejection, previously described as risk factors for OB in adults, were significantly more common in children, P = 0.004 and P = 0.001, respectively. Average forced expiratory volume in 1 s was lower in children than in adults for each 3-month period after transplantation (P < 0.001). In conclusion, identified risk factors for the development of OB were more common, and the risk of death from OB was greater in children than in adults following heart-lung transplantation.

Adolescent↗
PubMed1994

Donor and recipient predicted lung volume and lung size after heart-lung transplantation.

Lung volumes after heart-lung transplantation (HLT) were recorded and compared with measurements at the time of assessment for surgery and the predicted values for recipients. The influence of donor lung size and recipients' underlying lung disease was evaluated. All patients underwent HLT between April 1984 and April 1991, and only those 82 who survived for at least 6 mo were studied. Mean total lung capacity (TLC) at preoperative assessment was 112% (SD = 28%) of the value predicted for recipients. One month after HLT, mean TLC was 83% (SD = 15%) of the predicted value but increased to 100% (SD = 15%) after 9 mo. No further change in average TLC occurred for 5 yr subsequently. The mean TLC of patients with emphysema before surgery was 164% (SD = 26%) of the predicted value and fell to the predicted value within 1 mo of HLT. The TLC in patients with primary pulmonary hypertension before surgery was close to the predicted value, but postoperative predicted TLC was achieved later than in emphysema patients. A donor-versus-recipient difference in TLC of more than 1L at the time of assessment did not influence the adaptation to the predicted value. FEV1 and vital capacity (VC) rose from means of 70% (SD = 25%) and 63% (SD = 20%) at 1 mo to 96% (SD = 27%) and 91% (SD = 18%), respectively, at 9 mo after HLT. After HLT, TLC returns to the predicted value for the recipient, and not to the preoperative TLC.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗