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The effect of intravenous fixed-dose heparin during total hip arthroplasty on the incidence of deep-vein thrombosis
Vohme 15 Number 6 June 1992
the luminal surface was fully endothelialized and therefore not influenced by platelet deposition. Polytetratluoroethylene 4 mm internal diameter (60 pm internodal distance) 6 cm grafts were implanted bilaterally in the aortoiliac circulation of 10 kg baboons. This baboon graft model achieves complete endothelialization of the luminal surface in 2 weeks. The grafts aswell as comparable lengths of aorta and carotid arteries were removed, perfused, and the efferent evaluated for mitogenie activity at 2 weeks, 1 month, and 3 months, as well as for platelet degranulation products (platelet factor 4, B-thromboglobulin and lactate dehydrogenase) , To determine what portion of the mitogenic activity was from PDGF, a polyclonal goat anti-PDGF blocking antibody was added to the perfusate to neutralize all dimeric forms of PDGF and compared with those containing nonimmune IgG. The expression of PDGF mRNA in the intima cells of the grafts, as well as the normal control arteries, were evaluated by Northern analysis.Cells types in the grafts were identified with the use of monoclonal antibodies for endothelium (factor VIII related antigen), smooth muscle cell (HHF35), and macrophages (HAM 56). To localize the cellscontaining PDGF mRNA, in situ hybridization was performed. After endothelialization of the luminal surface (2 weeks), the predominant cell type detected in the intima were proliferating SMCs three fourths of which were found in the inner third of the intima adjacent to the endothelium. Although the perfusate from grafts and native artery had detectable levels of platelet degranulation products between 0 and 4 hours, no measurable levels were found between 8 and 22 hours of perfusion with the latter time frames used to calculate mitogenic activity. A higher level of mitogenic activity in the graft perfusate was found at all time periods of graft healing studied when compared with control arteries (p 5 0.05). This mitogenic activity was decreasedby 40% to 45% by polyclonal anti-PDGF when compared with nonimmune IgG. By use of Northern analysis, low levels of PDGF-B mRNA were detected in both artery and grafts, but the graft intima expressed higher levels of PDGF-A mRNA when compared with control arteries. In situ hybridization in grafts left in for 12 weeks detected PDGF-A chain mRNA primarily in the endothelial cellsand occasionallyin intimal SMC. In the 7.5 week grafts, similar levels of PDGF-A mRNA were found in endothelial cellsand in the SMCs throughout the graft intima, although PDGF-B chain mRNA hybridization was not detected. In summary, this excellent work elegantly demonstrates in a baboon arterial high porosity graft model that the endothelial cells are an important source of mitogens for SMC proliferation in a platelet free model. Since PDGF was only responsible for half of the mitogen activity, further elucidation of other growth factors and their origin will further clarify the pathophysiology of SMC proliferation in vascular graft healing. CreaorioA. Sicard,MD Washgton UniversitySchool of Medicine, St. Louis
AGstracts 1089
The effect of intravenous during total hip arthroplasty deep-vein thrombosis
fixed-dose heparin on the incidence of
A randomized, double-blind trial in patients operated on with epidural anesthesia and controlled hypotension Sharrock NE, Brien WW, SalvatiEA, Mineo R, Garvein K, sculco TP. The authors report the results of a prospective, double-blind study to assessthe effect of intravenous fixed-dose heparin on the incidence of deep vein thrombosis for patients undergoing epidural anesthesia. One hundred fifty patients were randomly assigned to two groups; however, 24 were excluded from the study becauseof failure to obtain venograms, noncompliance, or patient refusal. Therefore one hundred twenty-six patients comprised the study. Group I consisted of 66 patients who received preoperative intravenous saline solution, and group II consisted of 60 patients who received 1000 units of heparin 5 minutes before operation, and 500 units every 30 minutes until the end of operation. During hip replacement the patient’s mean arterial pressures were maintained at between 50 and 60 mm Hg. After operation, all patients received 650 mg of aspirin daily, and all patients wore elastic stockings. On the second and third postoperative day the patients walked with assistance,and ascending venography was performed on the seventh postoperative day. The incidence of deep-vein thrombosis was 24% (16 of 66 patients) in group I and only 8% (5 of 60) in group II; this difference was statistically significant, p = 0.03). Patients receiving prophylactic heparin had a greater intraoperative blood loss; however, no significant difference occurred in postoperative hemovac drainage. An average of less than 1 unit of blood was transfused for patients in each group. David Rosenthal, Atlanta, Ga.
MD
MRC European for symptomatic (O-29%) carotid
Carotid Surgery Trial: interim results patients with severe (70-99%) or mild stenosis
European Carotid Surgery Trialisr’ Collaborative Group. Lancet 1991;337:1235-43. The European Carotid Surgery Trial started in 1981 to study the possible benefit of endarterectomy for symptomatic patients with stenotic lesions in the relevant carotid artery. Symptoms included nondisabling carotid territory ischemic strokes, transient ischemic attacks, or retinal infarcts. Two thousand five hundred eighteen patients were entered from 80 centers in 14 countries. Eligibility was different from similar studies, being based on an “uncertainty principle.” Only patients whose physicians were “substantially uncertain” what to recommend were considered for randomization. Whenever the physicians were “reasonably certain” that they did or di.d not want to
the luminal surface was fully endothelialized and therefore not influenced by platelet deposition. Polytetratluoroethylene 4 mm internal diameter (60 pm internodal distance) 6 cm grafts were implanted bilaterally in the aortoiliac circulation of 10 kg baboons. This baboon graft model achieves complete endothelialization of the luminal surface in 2 weeks. The grafts aswell as comparable lengths of aorta and carotid arteries were removed, perfused, and the efferent evaluated for mitogenie activity at 2 weeks, 1 month, and 3 months, as well as for platelet degranulation products (platelet factor 4, B-thromboglobulin and lactate dehydrogenase) , To determine what portion of the mitogenic activity was from PDGF, a polyclonal goat anti-PDGF blocking antibody was added to the perfusate to neutralize all dimeric forms of PDGF and compared with those containing nonimmune IgG. The expression of PDGF mRNA in the intima cells of the grafts, as well as the normal control arteries, were evaluated by Northern analysis.Cells types in the grafts were identified with the use of monoclonal antibodies for endothelium (factor VIII related antigen), smooth muscle cell (HHF35), and macrophages (HAM 56). To localize the cellscontaining PDGF mRNA, in situ hybridization was performed. After endothelialization of the luminal surface (2 weeks), the predominant cell type detected in the intima were proliferating SMCs three fourths of which were found in the inner third of the intima adjacent to the endothelium. Although the perfusate from grafts and native artery had detectable levels of platelet degranulation products between 0 and 4 hours, no measurable levels were found between 8 and 22 hours of perfusion with the latter time frames used to calculate mitogenic activity. A higher level of mitogenic activity in the graft perfusate was found at all time periods of graft healing studied when compared with control arteries (p 5 0.05). This mitogenic activity was decreasedby 40% to 45% by polyclonal anti-PDGF when compared with nonimmune IgG. By use of Northern analysis, low levels of PDGF-B mRNA were detected in both artery and grafts, but the graft intima expressed higher levels of PDGF-A mRNA when compared with control arteries. In situ hybridization in grafts left in for 12 weeks detected PDGF-A chain mRNA primarily in the endothelial cellsand occasionallyin intimal SMC. In the 7.5 week grafts, similar levels of PDGF-A mRNA were found in endothelial cellsand in the SMCs throughout the graft intima, although PDGF-B chain mRNA hybridization was not detected. In summary, this excellent work elegantly demonstrates in a baboon arterial high porosity graft model that the endothelial cells are an important source of mitogens for SMC proliferation in a platelet free model. Since PDGF was only responsible for half of the mitogen activity, further elucidation of other growth factors and their origin will further clarify the pathophysiology of SMC proliferation in vascular graft healing. CreaorioA. Sicard,MD Washgton UniversitySchool of Medicine, St. Louis
AGstracts 1089
The effect of intravenous during total hip arthroplasty deep-vein thrombosis
fixed-dose heparin on the incidence of
A randomized, double-blind trial in patients operated on with epidural anesthesia and controlled hypotension Sharrock NE, Brien WW, SalvatiEA, Mineo R, Garvein K, sculco TP. The authors report the results of a prospective, double-blind study to assessthe effect of intravenous fixed-dose heparin on the incidence of deep vein thrombosis for patients undergoing epidural anesthesia. One hundred fifty patients were randomly assigned to two groups; however, 24 were excluded from the study becauseof failure to obtain venograms, noncompliance, or patient refusal. Therefore one hundred twenty-six patients comprised the study. Group I consisted of 66 patients who received preoperative intravenous saline solution, and group II consisted of 60 patients who received 1000 units of heparin 5 minutes before operation, and 500 units every 30 minutes until the end of operation. During hip replacement the patient’s mean arterial pressures were maintained at between 50 and 60 mm Hg. After operation, all patients received 650 mg of aspirin daily, and all patients wore elastic stockings. On the second and third postoperative day the patients walked with assistance,and ascending venography was performed on the seventh postoperative day. The incidence of deep-vein thrombosis was 24% (16 of 66 patients) in group I and only 8% (5 of 60) in group II; this difference was statistically significant, p = 0.03). Patients receiving prophylactic heparin had a greater intraoperative blood loss; however, no significant difference occurred in postoperative hemovac drainage. An average of less than 1 unit of blood was transfused for patients in each group. David Rosenthal, Atlanta, Ga.
MD
MRC European for symptomatic (O-29%) carotid
Carotid Surgery Trial: interim results patients with severe (70-99%) or mild stenosis
European Carotid Surgery Trialisr’ Collaborative Group. Lancet 1991;337:1235-43. The European Carotid Surgery Trial started in 1981 to study the possible benefit of endarterectomy for symptomatic patients with stenotic lesions in the relevant carotid artery. Symptoms included nondisabling carotid territory ischemic strokes, transient ischemic attacks, or retinal infarcts. Two thousand five hundred eighteen patients were entered from 80 centers in 14 countries. Eligibility was different from similar studies, being based on an “uncertainty principle.” Only patients whose physicians were “substantially uncertain” what to recommend were considered for randomization. Whenever the physicians were “reasonably certain” that they did or di.d not want to