374
Ann. Surg.April 1991
LETTERS TO THE EDITOR
Unlike patients undergoing elective abdominal surgery (who exhibit a decrease in the blood glutamine level), patients with early sepsis appear to have normal or slightly elevated blood glutamine levels. We agree with Dr. Planas and colleagues that this observation probably is due to a combination of a reduced uptake of glutamine by the bowel with an accelerated release of glutamine by skeletal muscle. The flux data is consistent with another organ of significant glutamine consumption during endotoxemia and preliminary data suggest that the liver becomes the principal organ of glutamine use during severe infection.5 WILEY W. SOUBA, M.D. Sc.D. Gainesville, Florida
References 1. Souba WW, Herskowitz K, Klimberg VS, et al. The effects of sepsis and endotoxemia on gut glutamine metabolism. Ann Surg 1990; 211:543-551. 2. Fox AD, Kripke SA, DePaula J, et al. Effect of a glutamine-supplemented enteral diet on methotrexate-induced enterocolitis. JPEN 1988; 12:325-33 1. 3. Burke D, Alverdy JC, Aoys E, et al. Glutamine supplemented TPN improves gut immune function. Arch Surg 1989; 124, 13961399. 4. Klimberg VS, Salloum RM, Kasper M, et al. Oral glutamine accelerates healing of the small intestine and improves outcome following whole abdominal radiation. Arch Surg 1990; 125:10401045. 5. Austgen TR, Chen MK, Flynn TC, Souba WW. The effects of endotoxin on the splanchnic metabolism of glutamine and related substrates. J Trauma (Submitted for publication).
August 3, 1990 Dear Editor: I read with interest a recent article "Reduction of Intimal Hyperplasia and Enhanced Reactivity of Experimental Vein Bypass Grafts with Verapamil Treatment."' However the method used to remove the vein was not according to established technique and thus prompts questions about the clinical implications of the study. In a series of experiments, LoGerfo et al.2'5 developed a technique for prevention of spasm and demonstrated with scanning electron micrographs essentially total preservation of endothelium in vein grafts and elimination of the intimal hyperplasia. The technique involves perivenous infiltration of a diluted papaverine solution, extreme gentleness in the dissection of the vein, early cannulation and distension with a Shiley vein distension set using warm papavarine (60 mg)/heparin (2000 U)/ plasmalyte (500 mL) solution, and storing the vein in the distended state in the same solution at 4°C. Baumann6 and Sottiurai7 in separate investigations confirmed the importance of papaverine, a balanced electrolyte solution, and prevention of overdistension of the vein segment. In the latest issue of Vascular Surgery, separate chapters, "In Situ Saphenous Vein Intimal Bypass" by Leather and Shah,8 and "Translocated Autogenous Vein Grafts" by Cambria and Abbott9 advocate this technique. Thus, while it is encouraging that a newer agent such as verapamil holds promise for further reduction of intimal hyperplasia, before it can be considered a clinical advancement, the experimental protocol should use it in comparison to the above optimal method of vein preparation. CHARLES C. PANISZYN, M.D. Providence, Rhode Island
References 1. El-Sanadiki MN, Cross KS, Murray JJ, et al. Reduction of intimal hyperplasia and enhanced reactivity of experimental vein bypass grafts with Verapamil treatment. Ann Surg 1990; 212:87-96. 2. Haudenschild CC, Quist WC, Gould KE, et al. Protection of endothelium in vessel segments excised for grafting. Circulation 1981; 64(Suppl 2): 101-107. 3. LoGerfo FW, Quist WC, Crenshaw, et al. An improved technique for preservation of endithelial morphology in vein grafts. Surgery 1981; 90:1015-1024. 4. LoGerfo FW, Quist WC, Cantelmo, et al. Integrity of vein grafts as a function of intimal and medial preservation. Circulation 1983; 68(Suppl 2):117-124. 5. LoGerfo FW, Haudenschild CC, Quist WC. A clinical technique for prevention of spasm and preservation of endothelium in saphenous vein grafts. Arch Surg 1984; 119:1212-1214. 6. Baumann FG, Catinella FP, Cunningham JN, Spencer FC. Vein contraction and smooth muscle cell extensions as cause of endothelial damage during graft preparation. Ann Surg 1981; 194: 199-211. 7. Sottiurai VS, Sue SL, Batson RC, et al. Effects of papaverine on smooth muscle cell morphology and vein graft preparation. J Vasc Surg 1985; 2:834-842. 8. Leather RP, Shah DM. In situ saphenous vein arterial bypass. In Rutherford RB, ed. Vascular Surgery. Philadelphia: WB Saunders, 1989, pp 415-425. 9. Cambria RP, Abbott WM. Translocated autogenous vein grafts. In Rutherford RB, ed. Vascular Surgery. Philadelphia: WB Saunders, 1989, pp 425-434.
October 24, 1990 Dear Editor: It has long been recognized that meticulous attention to the preservation of the endothelium during harvest, storage, and transplantation of autologous veins may have beneficial effects on the long-term patency rates.' The literature cited by Dr. Paniszyn supports this concept. Of note, however, are the facts that the method advocated by Dr. Paniszyn differs from the most recently cited publication by Dr. LoGerfo2 in that no albumin is included and that there are no available data from controlled trials examining the effect of this approach on short- and longterm graft patency. Currently available data on the optimal preservation of the endothelium in human saphenous veins remain controversial. In contrast to Dr. Paniszyn's comments, some authorities3 advocate the use of crystalloid solutions and warm temperatures, while others4 advocate the use of heparinized chilled autologous blood. The benefit of distention3'5 as well as the use of papaverine by perivenous infiltration3'6 and inclusion in the storage solution7 is still debated. One of us (RLM) has found an increased incidence of wound complications due to bleeding in the graft bed when papaverine is infiltrated locally. As recently noted by Lawrie,8 the use of papaverine or other relaxing agents such as nitroglycerin or calcium channel blockers needs to be investigated further. In our experiments the veins were treated identically before transplantation under conditions that we recognize may not be optimal for the preservation of the endothelium. This model is advantageous in that it is well characterized in terms of the development of intimal hyperplasia and because the hyperplasia develops within a short experimental period. In this setting verapamil clearly reduces intimal hyperplasia. The use of such a model to study the pharmacologic manipulation of intimal hyperplasia development is essential for situations that do not allow the preservation of the endothelium. Therefore this type of study is important in clinical procedures that damage the endothelium,
Ann. Surg.April 1991
LETTERS TO THE EDITOR
Unlike patients undergoing elective abdominal surgery (who exhibit a decrease in the blood glutamine level), patients with early sepsis appear to have normal or slightly elevated blood glutamine levels. We agree with Dr. Planas and colleagues that this observation probably is due to a combination of a reduced uptake of glutamine by the bowel with an accelerated release of glutamine by skeletal muscle. The flux data is consistent with another organ of significant glutamine consumption during endotoxemia and preliminary data suggest that the liver becomes the principal organ of glutamine use during severe infection.5 WILEY W. SOUBA, M.D. Sc.D. Gainesville, Florida
References 1. Souba WW, Herskowitz K, Klimberg VS, et al. The effects of sepsis and endotoxemia on gut glutamine metabolism. Ann Surg 1990; 211:543-551. 2. Fox AD, Kripke SA, DePaula J, et al. Effect of a glutamine-supplemented enteral diet on methotrexate-induced enterocolitis. JPEN 1988; 12:325-33 1. 3. Burke D, Alverdy JC, Aoys E, et al. Glutamine supplemented TPN improves gut immune function. Arch Surg 1989; 124, 13961399. 4. Klimberg VS, Salloum RM, Kasper M, et al. Oral glutamine accelerates healing of the small intestine and improves outcome following whole abdominal radiation. Arch Surg 1990; 125:10401045. 5. Austgen TR, Chen MK, Flynn TC, Souba WW. The effects of endotoxin on the splanchnic metabolism of glutamine and related substrates. J Trauma (Submitted for publication).
August 3, 1990 Dear Editor: I read with interest a recent article "Reduction of Intimal Hyperplasia and Enhanced Reactivity of Experimental Vein Bypass Grafts with Verapamil Treatment."' However the method used to remove the vein was not according to established technique and thus prompts questions about the clinical implications of the study. In a series of experiments, LoGerfo et al.2'5 developed a technique for prevention of spasm and demonstrated with scanning electron micrographs essentially total preservation of endothelium in vein grafts and elimination of the intimal hyperplasia. The technique involves perivenous infiltration of a diluted papaverine solution, extreme gentleness in the dissection of the vein, early cannulation and distension with a Shiley vein distension set using warm papavarine (60 mg)/heparin (2000 U)/ plasmalyte (500 mL) solution, and storing the vein in the distended state in the same solution at 4°C. Baumann6 and Sottiurai7 in separate investigations confirmed the importance of papaverine, a balanced electrolyte solution, and prevention of overdistension of the vein segment. In the latest issue of Vascular Surgery, separate chapters, "In Situ Saphenous Vein Intimal Bypass" by Leather and Shah,8 and "Translocated Autogenous Vein Grafts" by Cambria and Abbott9 advocate this technique. Thus, while it is encouraging that a newer agent such as verapamil holds promise for further reduction of intimal hyperplasia, before it can be considered a clinical advancement, the experimental protocol should use it in comparison to the above optimal method of vein preparation. CHARLES C. PANISZYN, M.D. Providence, Rhode Island
References 1. El-Sanadiki MN, Cross KS, Murray JJ, et al. Reduction of intimal hyperplasia and enhanced reactivity of experimental vein bypass grafts with Verapamil treatment. Ann Surg 1990; 212:87-96. 2. Haudenschild CC, Quist WC, Gould KE, et al. Protection of endothelium in vessel segments excised for grafting. Circulation 1981; 64(Suppl 2): 101-107. 3. LoGerfo FW, Quist WC, Crenshaw, et al. An improved technique for preservation of endithelial morphology in vein grafts. Surgery 1981; 90:1015-1024. 4. LoGerfo FW, Quist WC, Cantelmo, et al. Integrity of vein grafts as a function of intimal and medial preservation. Circulation 1983; 68(Suppl 2):117-124. 5. LoGerfo FW, Haudenschild CC, Quist WC. A clinical technique for prevention of spasm and preservation of endothelium in saphenous vein grafts. Arch Surg 1984; 119:1212-1214. 6. Baumann FG, Catinella FP, Cunningham JN, Spencer FC. Vein contraction and smooth muscle cell extensions as cause of endothelial damage during graft preparation. Ann Surg 1981; 194: 199-211. 7. Sottiurai VS, Sue SL, Batson RC, et al. Effects of papaverine on smooth muscle cell morphology and vein graft preparation. J Vasc Surg 1985; 2:834-842. 8. Leather RP, Shah DM. In situ saphenous vein arterial bypass. In Rutherford RB, ed. Vascular Surgery. Philadelphia: WB Saunders, 1989, pp 415-425. 9. Cambria RP, Abbott WM. Translocated autogenous vein grafts. In Rutherford RB, ed. Vascular Surgery. Philadelphia: WB Saunders, 1989, pp 425-434.
October 24, 1990 Dear Editor: It has long been recognized that meticulous attention to the preservation of the endothelium during harvest, storage, and transplantation of autologous veins may have beneficial effects on the long-term patency rates.' The literature cited by Dr. Paniszyn supports this concept. Of note, however, are the facts that the method advocated by Dr. Paniszyn differs from the most recently cited publication by Dr. LoGerfo2 in that no albumin is included and that there are no available data from controlled trials examining the effect of this approach on short- and longterm graft patency. Currently available data on the optimal preservation of the endothelium in human saphenous veins remain controversial. In contrast to Dr. Paniszyn's comments, some authorities3 advocate the use of crystalloid solutions and warm temperatures, while others4 advocate the use of heparinized chilled autologous blood. The benefit of distention3'5 as well as the use of papaverine by perivenous infiltration3'6 and inclusion in the storage solution7 is still debated. One of us (RLM) has found an increased incidence of wound complications due to bleeding in the graft bed when papaverine is infiltrated locally. As recently noted by Lawrie,8 the use of papaverine or other relaxing agents such as nitroglycerin or calcium channel blockers needs to be investigated further. In our experiments the veins were treated identically before transplantation under conditions that we recognize may not be optimal for the preservation of the endothelium. This model is advantageous in that it is well characterized in terms of the development of intimal hyperplasia and because the hyperplasia develops within a short experimental period. In this setting verapamil clearly reduces intimal hyperplasia. The use of such a model to study the pharmacologic manipulation of intimal hyperplasia development is essential for situations that do not allow the preservation of the endothelium. Therefore this type of study is important in clinical procedures that damage the endothelium,
