High early patency of saphenous vein graft for coronary artery bypass harvested with surrounding tissue.

BACKGROUND: Surgical trauma to the saphenous vein, used as a conduit for coronary artery bypass grafting, affects their occlusion rate. This study evaluates the early patency of saphenous vein grafts harvested with a pedicle of surrounding tissue that protects the vein from spasm and trauma. METHODS: Fifty-two patients underwent coronary artery bypass grafting with saphenous veins harvested with surrounding tissue. Forty-five patients, who received a total of 124 vein grafts and 42 left internal mammary arteries, underwent angiographic follow-up at a mean of 18 months (9 to 24 months). RESULTS: Patency for saphenous vein grafts was 95.4% and for left internal mammary arteries, it was 93.3%. Twenty-nine of 30 (96.7%) vein grafts anastomosed to arteries 2.0 mm or more, 65 of 67 (97%) grafts to 1.5 mm, and 10 of 13 (77%) anastomosed to 1-mm arteries were patent. Nineteen of 22 (86.4%) vein grafts with flow rates 20 mL/min or less, 32 of 34 (94.1%) with flow between 20 and 40 mL/min, and 50 of 51 (98%) with flow more than 40 mL/min were patent. Other registered surgical and clinical factors did not contribute to vessel occlusion. CONCLUSIONS: Early patency rate of saphenous veins harvested with surrounding tissue is very high, even in saphenous vein grafts demonstrating low blood flow. Preservation of graft endothelium using our harvesting technique may be the explanation of this success.

The evaluation of maternal anti-D concentrations during pregnancy.

Anti-D quantitation by the AutoAnalyzer technique has been shown to be a helpful aid in assessing the severity of D alloimmunization during pregnancy. In this study, the technique has been used both to detect antibody boosting after amniocentesis and to differentiate active D immunization from the presence of passive antibodies. The AutoAnalyzer technique and the more generally used indirect antiglobulin test titration method showed good agreement at titre levels of 32 or lower. A titre of 32 was found to be a good discriminative level to separate the mildly affected from the more severely affected newborns suffering from Rh haemolytic disease. At higher titre levels, however, the AutoAnalyzer technique was the method of choice for correct clinical assessment of the severity of D alloimmunization.

A management programme for Rh alloimmunization during pregnancy.

A management programme for the control and treatment of Rh0 (D) immunized during pregnancy is presented. A total of 34,650 births were registered during a 4.5 year period and included 63 D positive newborns to D-immunized mothers. The outcome of all infants has been evaluated according to the severity of the haemolytic disease. Exchange transfusion was unnecessary in 43 mild cases (68.3%). Fourteen infants (22.2%) required exchange transfusion, and in 6 severe cases (9.5%) maternal plasma exchange and exchange transfusion was performed. No detrimental effects or deaths occurred among the infants suffering from Rh haemolytic disease. We recommend that the frequency and volume of plasma exchange therapy should be individually adjusted to suit each patient and the effect monitored regularly through maternal anti-D levels using a sensitive quantitative technique.

Selection of monoclonal antibodies for the identification of D variants: ability to detect weak D and to split epD2, epD5 and epD6/7.

Red cells from known D variant donors were tested with 41 monoclonal anti-D reagents, 26 IgG and 15 IgM, with the view to selecting a panel to aid the identification of unusual D types. These antibodies gave reaction patterns which allowed the identification of most of the known D category cells, recognizing epD2, epD5, epD6/7, epD8 and epD9, but were unable to distinguish category III from normal D-positive cells. Reactivity with HMi, HMii, DFR, DBT and RoHar cells split epD2, epD5 and epD6/7 into two, three and eight groups, respectively. A panel comprising 15 monoclonal anti-D, 11 IgG and four IgM, was selected as representative of the antibodies tested. Reactivity of monoclonal anti-D was dependent on antibody concentration and antibody avidity. An antibody concentration of at least 12 micrograms/ml was required for optimum reactivity of the two monoclonal antibodies tested. A simple calculation of division of the titre by the antibody concentration provided a relatively simple means of establishing the reactivity performance of the antibody and correlated well with ability to detect weak D (Du) cells. A characteristic variable reduction in reaction strength with all the IgG anti-D was observed with weak D cells. The IgM antibodies, except the high avidity RUM-1, T3D2T6, D9A4 and BS226, performed poorly in detecting weak D. The majority of the IgM antibodies tested reacted with RoHarr cells, while only one IgG antibody was positive.

The prevalence of red cell antibodies in pregnancy correlated to the outcome of the newborn: a 12 year study in central Sweden.

BACKGROUND: All maternal red cell antibodies found during pregnancy in a 12 year period have been compiled. The efficacy of the current antenatal screening and management programme has been ascertained by reviewing the outcome of all newborns to these immunized mothers. METHOD: Patient selection was carried out by computerised searching for all known records of registered antibodies during the study period. Each mother's obstetric record and her baby's hospital file was studied and relevant clinical treatment and laboratory data on both mother and child was recorded and analysed. RESULTS: Eight hundred and twenty-one alloantibodies were detected in 629 immunized pregnant women with 753 fetuses. An overall antibody incidence of 0.57% was observed which included 373 clinically significant antibodies found in 261 mothers (0.24%). Multiple antibodies were present in 8.2% of all samples. Anti-D, by itself or in combination with other Rh-antibodies, caused more severe forms of hemolytic disease of the newborn (HDN) with 46% of all Rh-positive babies having phototherapy and 29% having exchange transfusion. Three of 18 Fya-positive infants required phototherapy and one required exchange transfusion and in the 16 Kell-positive babies, three required phototherapy and one required exchange transfusions. CONCLUSIONS: Few antibodies to blood group antigens other than those in the Rhesus system were found to cause severe HDN. Antibodies that are generally considered non-significant did not cause HDN in this study. All antibodies that induced HDN were detected in time so that adequate measures could be taken to reduce the effects in the newborn. The antenatal screening and management programme currently in use is considered to be reliable.

Severe Rh(D) immunization: anti-D quantitation and treatment possibilities during pregnancy and after birth.

An extremely aggressive Rh(D), (C) and Kell alloimmunization during pregnancy is reported. Exceptionally high concentrations of anti-D were observed in the mother, in the fetus and in the amniotic fluid, indicating an active transport across the placenta and a passive excretion into the amniotic fluid. Treatment during pregnancy included maternal plasmapheresis and high-dose intravenous immunoglobulin. Intravascular transfusions were given to the fetus. Postpartum the newborn was given immunoglobulin, one exchange transfusion and four top-up transfusions. In the newborn the elimination rate of anti-D could be followed. Not until almost 4 months postpartum did the anti-D concentration drop below the level of detection. This coincided with an elevated reticulocyte production and appearance of the child's true blood group in parallel with ceasing need for blood transfusions. Elimination rate and absolute anti-D values can be used as a prognostic tool to predict the need of blood transfusions. Immunoglobulin treatment can also be considered as an optional form of treatment in newborns affected by alloimmunization.

"No-touch" technique using saphenous vein harvested with its surrounding tissue for coronary artery bypass grafting maintains an intact endothelium.

Spasm and consequent dilation of the saphenous vein (SV) for coronary artery bypass grafting (CABG) can be avoided if the vein is harvested with its surrounding tissue. Morphologic techniques, including scanning and transmission electron microscopy, were used to compare endothelial cell integrity using three SV harvesting procedures: conventional (adventitial stripping of the vein, manual distention and storing in saline); intermediate (after adventitial stripping, the vein was left in situ, covered with a papaverine-soaked compress, and stored in heparinized blood); and "no-touch" (SV dissected with its surrounding tissue was left in situ, covered with a saline-soaked compress and stored in heparinized blood). Preservation of endothelial cell integrity was greater with the "no-touch" procedure than with the other methods. Since endothelial cell integrity of SV grafts may affect the patency rate, we conclude that the "no-touch" preparation should improve the results of CABG.

Inhibition of the monocyte chemiluminescent response to anti-D-sensitized red cells by Fc gamma RI-blocking antibodies which ameliorate the severity of haemolytic disease of the newborn.

Luminol-enhanced chemiluminescence (CL) may be used to measure the metabolic response of human monocytes to red cells sensitized by anti-D. The functional activity of maternal anti-D when measured in this way correlates with the severity of haemolytic disease of the newborn (HDN) in D-positive fetuses. Occasionally, however, women with levels of functionally active anti-D predictive of moderate to severe HDN may deliver D-positive babies with unexpectedly mild disease. In the current study we have shown that serum from 12 of 15 such women contained monocyte-binding IgG antibodies which blocked Fc gamma RI and inhibited the CL response of monocytes to red cells sensitized with monoclonal anti-D. In contrast, Fc gamma RI-blocking antibodies were found in the serum from only 4 of 11 women who were matched for anti-D activity but who delivered babies with severe HDN (p < 0.05). Antibodies responsible for inhibition of CL responses were predominantly against HLA class I antigens. The CL response of monocytes to sensitized red cells was at least as sensitive to inhibition by Fc gamma RI-blocking antibodies as were phagocytic and lytic responses. Our data suggest that inhibition of the CL test is an objective, sensitive and relatively simple technique for detecting and investigating Fc gamma RI-blocking antibodies which may ameliorate the severity of HDN.

Quantitative and functional asessment of anti-RhD: a comparative study of non-invasive methods in antenatal prediction of Rh hemolytic disease.

STUDY OBJECTIVE: To investigate if the prediction of hemolytic disease of the newborn (HDN) in infants of RhD immunized women has been improved by introduction of AutoAnalyzer quantitation and may be further improved by the use of a functional assay. METHODS: Manual antibody titration, AutoAnalyzer quantitation and chemiluminescence test (CLT) were compared by testing 42 sera from 38 RhD immunized mothers. The sera were also screened for the presence of monocyte-reactive antibodies which have the potential to protect the unborn. RESULTS: Among the 42 infants there were 19 unaffected by HDN and 23 affected by HDN. Manual titration correctly predicted the occurrence of HDN in 29/42 (69%), AutoAnalyzer was correct in 28/42 (67%) and CLT showed correct predictions with 30/42 (71%). In babies born without signs of HDN, maternal monocyte-reactive antibodies were found in 13/18 cases. The majority (9/13) were HLA class I-specific, the remaining four antibodies were either HLA class II or monocyte-specific. In affected HDN group, 8/16 monocyte-reactive anti- bodies were HLA class II or monocyte-specific. CONCLUSIONS: AutoAnalyzer and CLT improve the ability to discriminate unaffected babies from those affected by RhD HDN, when compared to manual titration. A protocol for the laboratory management of RhD immunized women is proposed that includes these tests to further improve the prediction of HDN. This study has also highlighted the need for more investigations into the protective role of monocyte-reactive antibodies in HDN.

Preserved endothelial integrity and nitric oxide synthase in saphenous vein grafts harvested by a 'no-touch' technique.

BACKGROUND: The saphenous vein is the most commonly used conduit for coronary artery bypass surgery, but 1-year occlusion rates as high as 30 per cent have been reported. In conventional surgery, considerable damage to the vein occurs during harvesting. The aim of this study was to compare endothelial integrity and nitric oxide synthase (NOS) in saphenous veins harvested by a novel 'no-touch' technique and veins harvested conventionally. METHODS: Immunohistochemistry was used to study endothelial integrity, and a combination of histochemistry and autoradiography was employed to identify NOS in human saphenous veins harvested by conventional and no-touch techniques. RESULTS: The endothelial lining of conventional grafts was reduced compared with that of no-touch grafts (52 versus 73 per cent; P = 0.04). This was associated with a concomitant reduction of NOS availability; NOS was also present in the adventitial vasa vasorum of no-touch vessels. CONCLUSION: Some of the sites with potential for nitric oxide release in vivo are removed during conventional saphenous vein harvesting. These sites were preserved after no-touch harvesting, suggesting the potential to improve coronary artery bypass graft patency.