Interleukin-6 gene promoter -174G/C polymorphism and insulin resistance: a pilot study.

BACKGROUND: The aim of this pilot study was to evaluate the relationship between interleukin-6 promoter -174G/C (IL-6 -174G/C) polymorphism and insulin resistance (IR) in obese patients with coronary heart disease (CHD). METHODS: Twenty obese male patients with CHD were selected from a larger database of patients (n=606). IL-6 -174G/C genotype was previously analysed and only homozygotes with the CC genotype (n=10) or GG genotype (n=10) were selected. IR was measured using the homeostasis model assessment for IR (HOMA-IR) method. RESULTS: Differences in age, body mass index, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), hypertension, IL-6, C-reactive protein and HOMA-IR were not significant between the genotypes (p>0.05), but analysis of a homogeneity-of-slopes model showed that genotype had a significant influence on HOMA-IR (p=0.037), and the interaction between genotype and HDL-C had a pronounced tendency to affect HOMA-IR (p=0.058). Using multiple regression analysis, we found that HDL-C had a significant effect on HOMA-IR (p=0.023), and TG had a tendency to affect HOMA-IR (p=0.066) only in the CC genotype. CONCLUSIONS: Our data show that IL-6 -174G/C polymorphism may have a significant effect on IR. A comparison between the effects of various cardiovascular risk factors showed that HDL-C may have a significant effect on HOMA-IR in the CC genotype but not in the GG genotype. Further research is needed to test the preliminary results.     

The importance of iliac fixation in prevention of stent graft migration

OBJECTIVE: Secure proximal fixation of endografts to the infrarenal aortic neck is known to be important in the short- and long-term success of endovascular aneurysm repair. We sought to determine the relative importance of distal iliac fixation in preventing endograft migration and adverse clinical events after endovascular aneurysm repair. METHODS: We reviewed the outcome of 173 patients treated from 1996 to 2003 at Stanford University Medical Center with an externally supported stent graft. Quantitative image analysis of the postimplantation computed tomography scan was performed to determine the proximal aortic and distal iliac fixation lengths and the proximity the distal end of the stent graft to the iliac bifurcation. Subsequent follow-up computed tomography scans were reviewed for evidence of stent graft migration. Patients were grouped according to good (>15 mm), intermediate, or bad (<10 mm) aortic fixation and good (iliac fixation length > or =25 mm and iliac limbs <10 mm from iliac bifurcation), intermediate, or bad (<25-mm fixation length) iliac fixation. RESULTS: Stent graft migration of 10 mm or more was seen in 17 patients (10%) during the 23 +/- 19-month follow-up period. Patients with no migration had a greater iliac fixation length (30 +/- 12 mm) than those with migration (22 +/- 8 mm; P = .01), and the distal ends of the iliac limbs were closer to the iliac bifurcation (15 +/- 12 mm) than in patients with migration (25 +/- 10 mm; P < .001). Patients with no migration also had a greater proximal aortic fixation length (23 +/- 12 mm) than migration patients (13 +/- 7 mm; P = .001). There were no migrations among patients with good iliac fixation whether aortic fixation was good, intermediate, or bad (0/63; 0%). Among patients with bad/intermediate iliac and good aortic fixation, there were 5 (9%) of 58 patients had migrations. Patients with both bad/intermediate iliac and bad/intermediate aortic fixation had the highest migration rate (12/52; 23%). Cox proportional hazards regression modeling revealed that the significant factors predicting migration were poor proximity of the distal end of the iliac limbs to the iliac bifurcation (odds ratio 17.2; P = .01) and aortic fixation length (odds ratio 2.0; p = 0.007 for each centimeter). Iliac extender modules were placed in 9 patients with bad iliac fixation and migration, with no further migration during a mean follow-up of 12 months. Patients with good iliac and aortic fixation and no endoleak on the initial postprocedure computed tomography scan (n = 43) had no migrations, secondary procedures, or adverse clinical events over a 2-year follow-up period. CONCLUSIONS: Iliac fixation, along with proximal aortic fixation, is an important factor in preventing the migration of stent grafts that have longitudinal columnar support. Patients with good iliac fixation did not experience migration even in the presence of suboptimal proximal aortic fixation. Close proximity of the distal end of the stent graft to the iliac bifurcation seems to provide stability against migration.