798
Journal of VASCULAR SURGERY
Letters to the Editors
ography to provide accurate control data before and after intervention. In this regard, intravascular ultrasound (IVUS) imaging may add a new perspecrive by (1) defining the types and spatial distribution of disease within the artery and (2) providing precise control cross-sectional dimensions of the vessel before and after intervention. Studies comparing IVUS and angiography in imaging atherosclerotic arteries have shown that angiography underestimates the extent of disease in vessels that contain either extensive or eccentrically located atheroma. 4,s It is therefore questionable whether angiography should be used as the gold standard for quantitating restenosis, particallarly because IVUS offers a more precise alternative and can also evaluate the transmural disease distribution. Refinement of the 1VUS-guided removal and debulking of lesions may be the key to improving long-term patency while dramatically decreasing complications from dissection and perforation of the arterial wall. Rodney A. White, MD Chief of Vascular Surgery Douglas 34. Cavaye, MZ) Vascular Surgeon Harbor-UCLA Medical Center Torrance, CA 90509
REFERENCES
material in infrageniculate and infrapopliteal locations. In the discussion of their article, several other variations were suggested that included performance of the proximal component alone or with use of composites constructed from other vein donor sites including the upper extremity. The authors go on to state that "the composite sequential configuration appears to provide superior extended patency rates.., compared w i t h . . , prosthetic tibial bypass grafts .... " What was not included in their article or the discussion was the alternative of use of a prosthetic graft with a distal arteriovenous fistula. Our experience 2 indicates that patency rates comparable to those achieved by McCarthy et al. can also be obtained with prosthetics if a means is devised to decrease distal resistance to flow and simultaneously increase graft flow above critical thromboric threshold velocity levels. In our most recent patients, 2-year graft patency rates for distal reconstructions with use of umbilical vein grafts plus distal arteriovenous fistulas exceed 60%, a figure virtually identical to that presented by McCarthy et al. (64%). It seems appropriate that a multicenter, randomized, prospective study be performed to define the role of all of these procedures that are now generally performed as individualized directed studies. Original contributions are essential to initiate progress, but the ultimate bias factors (including mine!) that become introduced, even unwittingly, can be dispelled only by critical and dispassionate use of the "scientific method."
1. Adams DH, Schoen FJ. Contemporary concepts in atherosclerosis pathology. In: White RA, ed. Atherosderosis and arteriosclerosis: human pathology and experimental animal methods and models. Boca Raton: CRC Press, 1989:49-86. 2. Clowes AW. Pathologic intimal hyperplasia as a response to vascular injury and reconstruction. In: Rutherford RB, ed. Vascular surgery. 3rd ed. Philadelphia: WB Sannders, 1989: 266-75. 3. Inahara T, Mukherjee D. Femoral and popliteal thromboendarterectomy. In: Rutherford RB, ed. Vascular surgery. 3rd ed. Philadelphia: WB Sannders, 1989:731-43. 4. Tobis JM, Mahon D, Lehmann K, McRae M, Henry WL. The sensitivity of ultrasound imaging compared with angiography for diagnosing coronary atherosclerosis [Abstract]. Circulation 1990;82(suppl III) :439. 5. Tabbara MR, White RA, Cavaye DM, Kopchok GE. In vivo human comparison of intravascular ultrasound and angiography. J VAse SURG 199I;14:496-504.
Herbert Dardik, MD, FACS Englewood Hospital 350 Engle St. Englewood, NJ 07631
24/40816
To the Editors: In his letter Dr. Dardik has reminded us of a technique that uses distal arteriovenous fistula to enhance flow through a prosthetic femorotibial bypass graft. This has intriguing theoretic potential, and he has referenced his published experience with 207 patients, subgrouped into 61 grafts completed before 1983 and reported in a previous paper with 2-year patency rates of 18%. Group 1I includes 80 bypass grafts between 1983 and 1986 with patency rates reported at 33% after 2 years. Group III patients were operated on between 1986 and 1989, and of the 69 bypasses, nine were completed with autogenous vein.
Long-term evaluation o f composite sequential bypass for limb-threatening ischemia To the Editors: McCarthy et al? clearly show the importance of including the composite sequential bypass method in the repertoire of vascular surgeons for establishing durable blood flow to the severely ischemic lower limb. This is based on the universal recognition of the superior performance of autologous vein compared with any prosthetic
REFERENCES
1. McCarthy WJ, Pearce WH, Flinn WR, McGee GS, Wang R, Yao JST. Long-term evaluation of composite sequential bypass for limb-threatening ischemia. J VAsc SURG1992;15:761-70. 2. Dardik H, Berry SM, Dardik A, et al. Infrapopliteal prosthetic graft patency by use of the distal adjunctive arteriovenous fistula. J VAsc SURG 1991;13:685-91. 24/41/41082
Reply
Journal of VASCULAR SURGERY
Letters to the Editors
ography to provide accurate control data before and after intervention. In this regard, intravascular ultrasound (IVUS) imaging may add a new perspecrive by (1) defining the types and spatial distribution of disease within the artery and (2) providing precise control cross-sectional dimensions of the vessel before and after intervention. Studies comparing IVUS and angiography in imaging atherosclerotic arteries have shown that angiography underestimates the extent of disease in vessels that contain either extensive or eccentrically located atheroma. 4,s It is therefore questionable whether angiography should be used as the gold standard for quantitating restenosis, particallarly because IVUS offers a more precise alternative and can also evaluate the transmural disease distribution. Refinement of the 1VUS-guided removal and debulking of lesions may be the key to improving long-term patency while dramatically decreasing complications from dissection and perforation of the arterial wall. Rodney A. White, MD Chief of Vascular Surgery Douglas 34. Cavaye, MZ) Vascular Surgeon Harbor-UCLA Medical Center Torrance, CA 90509
REFERENCES
material in infrageniculate and infrapopliteal locations. In the discussion of their article, several other variations were suggested that included performance of the proximal component alone or with use of composites constructed from other vein donor sites including the upper extremity. The authors go on to state that "the composite sequential configuration appears to provide superior extended patency rates.., compared w i t h . . , prosthetic tibial bypass grafts .... " What was not included in their article or the discussion was the alternative of use of a prosthetic graft with a distal arteriovenous fistula. Our experience 2 indicates that patency rates comparable to those achieved by McCarthy et al. can also be obtained with prosthetics if a means is devised to decrease distal resistance to flow and simultaneously increase graft flow above critical thromboric threshold velocity levels. In our most recent patients, 2-year graft patency rates for distal reconstructions with use of umbilical vein grafts plus distal arteriovenous fistulas exceed 60%, a figure virtually identical to that presented by McCarthy et al. (64%). It seems appropriate that a multicenter, randomized, prospective study be performed to define the role of all of these procedures that are now generally performed as individualized directed studies. Original contributions are essential to initiate progress, but the ultimate bias factors (including mine!) that become introduced, even unwittingly, can be dispelled only by critical and dispassionate use of the "scientific method."
1. Adams DH, Schoen FJ. Contemporary concepts in atherosclerosis pathology. In: White RA, ed. Atherosderosis and arteriosclerosis: human pathology and experimental animal methods and models. Boca Raton: CRC Press, 1989:49-86. 2. Clowes AW. Pathologic intimal hyperplasia as a response to vascular injury and reconstruction. In: Rutherford RB, ed. Vascular surgery. 3rd ed. Philadelphia: WB Sannders, 1989: 266-75. 3. Inahara T, Mukherjee D. Femoral and popliteal thromboendarterectomy. In: Rutherford RB, ed. Vascular surgery. 3rd ed. Philadelphia: WB Sannders, 1989:731-43. 4. Tobis JM, Mahon D, Lehmann K, McRae M, Henry WL. The sensitivity of ultrasound imaging compared with angiography for diagnosing coronary atherosclerosis [Abstract]. Circulation 1990;82(suppl III) :439. 5. Tabbara MR, White RA, Cavaye DM, Kopchok GE. In vivo human comparison of intravascular ultrasound and angiography. J VAse SURG 199I;14:496-504.
Herbert Dardik, MD, FACS Englewood Hospital 350 Engle St. Englewood, NJ 07631
24/40816
To the Editors: In his letter Dr. Dardik has reminded us of a technique that uses distal arteriovenous fistula to enhance flow through a prosthetic femorotibial bypass graft. This has intriguing theoretic potential, and he has referenced his published experience with 207 patients, subgrouped into 61 grafts completed before 1983 and reported in a previous paper with 2-year patency rates of 18%. Group 1I includes 80 bypass grafts between 1983 and 1986 with patency rates reported at 33% after 2 years. Group III patients were operated on between 1986 and 1989, and of the 69 bypasses, nine were completed with autogenous vein.
Long-term evaluation o f composite sequential bypass for limb-threatening ischemia To the Editors: McCarthy et al? clearly show the importance of including the composite sequential bypass method in the repertoire of vascular surgeons for establishing durable blood flow to the severely ischemic lower limb. This is based on the universal recognition of the superior performance of autologous vein compared with any prosthetic
REFERENCES
1. McCarthy WJ, Pearce WH, Flinn WR, McGee GS, Wang R, Yao JST. Long-term evaluation of composite sequential bypass for limb-threatening ischemia. J VAsc SURG1992;15:761-70. 2. Dardik H, Berry SM, Dardik A, et al. Infrapopliteal prosthetic graft patency by use of the distal adjunctive arteriovenous fistula. J VAsc SURG 1991;13:685-91. 24/41/41082
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