[Factors determining late patency of aortobifemoral bypass graft]

Most of the patients with aortoiliac occlusive diseases have a multilevel localization of atherosclerotic diseases. In patients with aortoiliac occlusive diseases, the femoro-popliteal segment is involved in 28 to 66% of cases. These patients are usually old persons with many risk factors. Therefore, simultaneous proximal and distal reconstruction is often associated with a higher morbidity and mortality rates. In contrast, can proximal reconstruction help only patients with multilevel occlusive diseases? The aim of this paper is: definition of factors determining late patency rate of aortobifemoral bypass graft in patients with multilevel occlusive diseases; definition of factors determining clinical effects after aortobifemoral bypass procedures.

This prospective study included 283 aortobifemoral reconstructions due to aortoiliac occlusive diseases operated between January 1st, 1984 and December 31st, 1992 at the Institute of Cardiovascular Diseases of the Serbian Clinical Centre in Belgrade. Bifurcated polytetrafluorethylene (PTFE) grafts were used in 136 patients, and standard nonimpregnated knitted Dacron grafts in 147 paetients. There were 25 (8.8%) female and 258 (91.2%) male patients, average age 56.88 years. Ninety one (32.2%) patients had claudication discomfort (Fonten stadium II), 91 (32.2%) disabling claudication discomfort (Fonten stadium IIb), 45 (15.9%) rest pain (Fonten stadium III), and 56 (19.8%) gangrene (Fonten stadium IV). In 45 (15.9%) patients previous vascular procedures were performed. Prior to operation Doppler ultrasonography and translumbar aortography were done. Isolated aortoiliac occlusive diseases with intact femoro-popliteal segment (Type I) were found in 83 (29.3%) patients; combined aorto-iliac and diseases of superficial femoral artery (Type II) in 170 (60%) patients; and combined aorto-iliac and femoro-popliteal diseases (Type III) in 30 (10.7%) individuals. Transperitoneal approach to abdominal aorta and standard inguinal approach to femoral arteries, were used. In 154 (54.4%) patients proximal anastomosis had an end to side (TL), while in 129 (45.6%) end to end (TT) form. In 152 (26.88%) patients distal anastomosis was found on the common femoral artery (AFC), while in 414 (73.2%) on the deep femoral artery (APF). In 7 patients the aorto-femoro-popliteal "jumping" bypass was performed, and in 29 subjects the simultaneous sequential femoro-popliteal bypass graft (Figures 1, 2, 3, 4a and 4b). The patients were followed-up over a period from one, six and twelve months after reconstruction, and later once a year, using physical examination and Doppler ultrasonography. In patients with suspected graft occlusion, anastomotic stenosis, pseudoaneurysms, progression of distal diseases, Duplex ultrasonography and angiography were also used, and leukoscintigraphy in patients with suspected graft infection. Statistical analysis was performed by Long Rank and Student's t-test.

Inhospital mortality rate was 11 (7%). Simultaneous distal reconstructions significantly increased the mortality rate (p< 0.01). The follow-up period was from 2 months to 9.5 years (mean 3.6 years). Configuration of proximal anastomosis showed no significant influence on graft patency (p>0.05) (Graphs 1, 2, 3). Location of distal anastomosis at the deep femoral artery contributed to statistically significant increase in graft patency (p < 0.01) (Graphs 4, 5, 6). Simultaneous distal bypass showed statistically significant increase in graft patency (p < 0.01), but also significant increase in inhopsital mortality rate (p < 0.01) (Graphs 7, 8, 9). The type of occlusive diseases had no statistically significant influence on graft patency (p > 0.05) (Graphs 10, 11, 12). Six (2.1%) early unilateral limb occlusions were observed. The reasons for early graft occlusions were: stenosis of distal anastomosis in 3 patients and pure run off in 3 subjects. In 5 patients urgent reoperations (limb thrombectomy and profundoplasty or femoro-popliteal bypass graft above the knee) were performed with complete recovery of patients. However, in one patient an above the knee amputation had to be done. During the follow-up period 14 (5.2%) late graft occlusions were recorded: 11 unilateral limb and 3 bilateral graft occlusions. The reasons for late graft occlusion were: distal progression of atherosclerotic diseases, distal anastomotic stenosis, proximal progression of atherosclerotic diseases and anastomotic neointimal hyperplasy. All patients with late graft occlusion underwent successful redo-operations. Next late redo-procedures had to be done: three new aorto-bifemoral bypass grafts (patients with bilateral occlusion), two limb thrombectomies, 6 limb thrombectomies with profundoplasty and 3 femoro-femoral "cross-over" bypass grafts. Configuration of proximal anastomosis and type of occlusive disease showed no statistically significant influence on the number of early and late graft occlusions (p > 0.05). Location of distal anastomosis at the deep femoral artery and simultaneous distal bypass, statistically significantly decreased the number of early and late graft occlusions (p < 0.05). "Small aorta syndrome" statistically significantly increased the number of late graft occlusions. Eleven distal anastomotic pseudoaneurysms were noted. In 8 patients pseudoaneurysms were infected and in 3 noninfected. In all patients new redo-operations were carried out. Graft infection was recorded in 5 (1.7%) patients. One (0.3%) secondary aortoduodenal fistula was found. During the follow-up period new disabling claudication discomforts were found in 46 patients. The causes were distal anastomotic stenosis in 30 patients and progression of distal arterial diseases in 16 subjects. Of the total number of 30 patients with distal anastomotic stenosis 14 were reoperated (profundoplasty) and 16 patients refused a new operation. Also, 16 patients with progression of distal atherosclerotic diseases were reoperated. The operation was a kind of femoropopliteal or crural bypass grafts. During the follow-up period 97 patients were asymptomatic, 128 showed significant improvement, 29 had disabling claudications, and 111 had amputations. Distal anastomosis at the deep femoral artery and patent superficial femoral artery, statistically significantly influenced the clinical course after operation (p 0.01), while configuration of proximal anastomosis and simultaneous distal bypass had no significant effects (p < 0.05).

(1) Only location of distal anastomosis has a statistically significant influence on the patency of aorto-bifemoral bypass graft. (2) The location of distal anastomosis and type of occlusive disease have a statistically significant influence on the clinical effect of the operation. (3) The simultaneous distal bypass had no influence on the late patency of aortobifemoral bypass graft and on the number of asymptomatic patients. Also, it increased inhospital mortality rate.