Lack of diameter effect on short-term patency of size-matched Dacron aortobifemoral grafts Joseph R. Schneider, M D , P h D , R o b e r t M. Zwolak, M D , PhD, Daniel B. Walsh, M D , M a r t h a D. McDaniel, M D , and Jack L. Cronenwett, M D ,
Hanover, New Hampshire This study examined the relationship between graft diameter and subsequent patency in 79 patients who received Dacron aortobifemoral bypass grafts for aortoiliac occlusive disease between 1985 and 1989. Sixty-five percent of these patients were men, 25% were diabetic, and 94% were smokers, with an average age of 62 years. Patients were followed for a mean interval of 24 months. Life-table survival was 92% at 3 years. All surviving patients showed "significant" postoperative improvement by use of Society for Vascular Surgery/International Society for Cardiovascular Surgery combined clinical and vascular laboratory criteria. There were three early and five late graft thromboses. Primary and secondary life-table patencies were 85% and 92%, respectively, at 3 years. Dacron bifurcation grafts were selected to match the size of native arteries. Patients receiving small diameter grafts, defined as 12 ram (n = 9) and 14 mm (n = 39), were compared with patients receiving large diameter grafts of 16 mm (n = 26) and 18 mm (n = 5). Small diameter grafts were more likely to be used in women (p < 0.01), but patient groups were otherwise comparable with respect to age, smoking history, diabetes, outflow status, operative indications, type of proximal anastomosis (end-to-end or end-to-side), location of distal anastomosis (common femoral vs deep femoral), type of graft construction (knitted vs woven), and functional result. Graft diameter did not influence life-table patency, which was 84% for small and 87% for large diameter grafts at 3 years (p = 0.74). Furthermore, none of the other variables listed above influenced graft patency. We conclude that Dacron aortobifemoral graft patency is not affected by graft diameter when appropriately matched to native vessel size. (J VAse Strg~ 1991;13:785-91.)
Aortobifemoral bypass surgery achieves excellent graft patency and limb salvage in patients with aortoiliac atherosclerotic occlusive disease.l-7 Despite the frequent use of this procedure, however, details concerning optimal graft size are unavailable. Historically, larger diameter Dacron grafts (18 to 20 ram) were used, apparently because of concerns that graft pseudointima and anastomotic neointimal hyperplasia would more likely compromise the lumen of small diameter grafts. In more recent years there appears to be a trend toward the use of smaller diameter Dacron bifurcation grafts that are sized in proportion to the native arteries. Artery size has also influenced the choice of graft material. Polytetraflu-
From the Section of Vascular Surgery, Dartmouth-Hitchcock Medical Center, Hanover. Presented at the SeventeenthAnnual Meeting of the New England Society for VascularSurgery,Newport, R.I., Sept. 13-14, 1990. Reprint requests: Joseph R. Schneider, MD, Phi), Section of Vascular Surgery, Dartmouth-Hitchcock Medical Center, Hanover, NH 03756.
24/6/28087
oroethylene (PTFE) grafts have been specifically recommended for patients requiring 14 m m and smaller diameter aortobifemoral grafts because of apparently superior patency. ~ The purpose of this review was to investigate the effect of graft diameter on patency and functional results in patients receiving Dacron aortobifemoral grafts for occlusive disease during the past 5 years. P A T I E N T S A N D M E T H O D S O F STUDY All patients undergoing aortobifemoral bypass with a Dacron prosthesis for aortoifiac occlusive disease at the Dartmouth-Hitchcock Medical Center between July 1985 and December 1989 were included in this study. Patients undergoing aortic reconstruction for aneurysmal or combined aneurysmal-occlusive disease were excluded. Since PTFE grafts were used infrequently, these were also excluded. Data were collected retrospectively by review of patient records. Current status was determined at most recent office visit and with a mailed questionnaire. 785
786
Schneider
Original arteriograms were reviewed to quantitate deep femoral and superficial femoral artery occlusive disease so that graft outflow could be graded according to Society for Vascular Surgery/International Society for Cardiovascular Surgery (SVS/ISCVS) criteria? In this system the range of possible outflow scores for each femoral anastomosis is 1 (optimal) to 10 (total occlusion), and for the entire graft is 0.5 (optimal) to 5.0 (both sides occluded). The levels of preoperative and postoperative chronic ischcmia were graded on a scale of 0 (no ischemia) to 6 (profound ischemia with certain limb loss) based on SVS/ISCVS guidelines? Each patient's current assessment of outcome was obtained by a questionnaire designed to determine whether the symptoms leading to operation were completely relieved, partially relieved, unchanged, or worse after surgery. Functional outcome was determined by use of a combination of clinical and vascular laboratory criteria and was graded from - 3 (significant worsening of symptoms or limb loss, with worsening noninvasive studies) to + 3 (complete relief of symptoms, with near normalization of noninvasive studies) based on SVS/ISCVS standards? Graft patency was defined by (1) arteriographic or duplex scan confirmation of graft limb patency; or (2) a persistent increase in the ankle-brachial index (ABI) of at least 0.10 after operation and maintenance of an ABI within 0.10 of the maximum postoperative value? Primary graft patency was defined as uninterrupted patency of both graft limbs without any secondary surgical procedures directed at the graft or to the immediately adjacent outflow vessel. Secondary patency was defined as patency of both graft limbs at follow-up with any secondary procedure. Continuous variables were compared between stratification groups with Student's t test, analysis of variance (ANOVA), and linear regression analysis. Categorical variables were compared by chi-square analysis or Fisher's exact test where appropriate. Life-table methods and log rank testing (Mantel) were used to compare graft patency between stratification groups. '°''~ A two-tailed test was used in all statistical comparisons, and a p value
Hanover, New Hampshire This study examined the relationship between graft diameter and subsequent patency in 79 patients who received Dacron aortobifemoral bypass grafts for aortoiliac occlusive disease between 1985 and 1989. Sixty-five percent of these patients were men, 25% were diabetic, and 94% were smokers, with an average age of 62 years. Patients were followed for a mean interval of 24 months. Life-table survival was 92% at 3 years. All surviving patients showed "significant" postoperative improvement by use of Society for Vascular Surgery/International Society for Cardiovascular Surgery combined clinical and vascular laboratory criteria. There were three early and five late graft thromboses. Primary and secondary life-table patencies were 85% and 92%, respectively, at 3 years. Dacron bifurcation grafts were selected to match the size of native arteries. Patients receiving small diameter grafts, defined as 12 ram (n = 9) and 14 mm (n = 39), were compared with patients receiving large diameter grafts of 16 mm (n = 26) and 18 mm (n = 5). Small diameter grafts were more likely to be used in women (p < 0.01), but patient groups were otherwise comparable with respect to age, smoking history, diabetes, outflow status, operative indications, type of proximal anastomosis (end-to-end or end-to-side), location of distal anastomosis (common femoral vs deep femoral), type of graft construction (knitted vs woven), and functional result. Graft diameter did not influence life-table patency, which was 84% for small and 87% for large diameter grafts at 3 years (p = 0.74). Furthermore, none of the other variables listed above influenced graft patency. We conclude that Dacron aortobifemoral graft patency is not affected by graft diameter when appropriately matched to native vessel size. (J VAse Strg~ 1991;13:785-91.)
Aortobifemoral bypass surgery achieves excellent graft patency and limb salvage in patients with aortoiliac atherosclerotic occlusive disease.l-7 Despite the frequent use of this procedure, however, details concerning optimal graft size are unavailable. Historically, larger diameter Dacron grafts (18 to 20 ram) were used, apparently because of concerns that graft pseudointima and anastomotic neointimal hyperplasia would more likely compromise the lumen of small diameter grafts. In more recent years there appears to be a trend toward the use of smaller diameter Dacron bifurcation grafts that are sized in proportion to the native arteries. Artery size has also influenced the choice of graft material. Polytetraflu-
From the Section of Vascular Surgery, Dartmouth-Hitchcock Medical Center, Hanover. Presented at the SeventeenthAnnual Meeting of the New England Society for VascularSurgery,Newport, R.I., Sept. 13-14, 1990. Reprint requests: Joseph R. Schneider, MD, Phi), Section of Vascular Surgery, Dartmouth-Hitchcock Medical Center, Hanover, NH 03756.
24/6/28087
oroethylene (PTFE) grafts have been specifically recommended for patients requiring 14 m m and smaller diameter aortobifemoral grafts because of apparently superior patency. ~ The purpose of this review was to investigate the effect of graft diameter on patency and functional results in patients receiving Dacron aortobifemoral grafts for occlusive disease during the past 5 years. P A T I E N T S A N D M E T H O D S O F STUDY All patients undergoing aortobifemoral bypass with a Dacron prosthesis for aortoifiac occlusive disease at the Dartmouth-Hitchcock Medical Center between July 1985 and December 1989 were included in this study. Patients undergoing aortic reconstruction for aneurysmal or combined aneurysmal-occlusive disease were excluded. Since PTFE grafts were used infrequently, these were also excluded. Data were collected retrospectively by review of patient records. Current status was determined at most recent office visit and with a mailed questionnaire. 785
786
Schneider
Original arteriograms were reviewed to quantitate deep femoral and superficial femoral artery occlusive disease so that graft outflow could be graded according to Society for Vascular Surgery/International Society for Cardiovascular Surgery (SVS/ISCVS) criteria? In this system the range of possible outflow scores for each femoral anastomosis is 1 (optimal) to 10 (total occlusion), and for the entire graft is 0.5 (optimal) to 5.0 (both sides occluded). The levels of preoperative and postoperative chronic ischcmia were graded on a scale of 0 (no ischemia) to 6 (profound ischemia with certain limb loss) based on SVS/ISCVS guidelines? Each patient's current assessment of outcome was obtained by a questionnaire designed to determine whether the symptoms leading to operation were completely relieved, partially relieved, unchanged, or worse after surgery. Functional outcome was determined by use of a combination of clinical and vascular laboratory criteria and was graded from - 3 (significant worsening of symptoms or limb loss, with worsening noninvasive studies) to + 3 (complete relief of symptoms, with near normalization of noninvasive studies) based on SVS/ISCVS standards? Graft patency was defined by (1) arteriographic or duplex scan confirmation of graft limb patency; or (2) a persistent increase in the ankle-brachial index (ABI) of at least 0.10 after operation and maintenance of an ABI within 0.10 of the maximum postoperative value? Primary graft patency was defined as uninterrupted patency of both graft limbs without any secondary surgical procedures directed at the graft or to the immediately adjacent outflow vessel. Secondary patency was defined as patency of both graft limbs at follow-up with any secondary procedure. Continuous variables were compared between stratification groups with Student's t test, analysis of variance (ANOVA), and linear regression analysis. Categorical variables were compared by chi-square analysis or Fisher's exact test where appropriate. Life-table methods and log rank testing (Mantel) were used to compare graft patency between stratification groups. '°''~ A two-tailed test was used in all statistical comparisons, and a p value
