Estrogen replacement attenuates exaggerated neointimal hyperplasia following carotid endarterectomy in rats

BACKGROUND

To investigate whether estrogen may attenuate neointima formation in hyperhomocysteinemic rat carotid endarterectomy.

METHODS

Rats were divided into 6 groups: ovariectomized estradiol-treated homocysteine or chow; ovariectomized placebo-treated homocysteine or chow; intact placebo-treated homocysteine or chow. Chow served as controls while homocysteine served as exaggerated intimal hyperplasia. Prior to endarterectomy, rats were implanted with estradiol mini-pump or placebo, diets given 2 weeks before and after surgery. Homocysteine, estrogen, and neointimal hyperplasia were determined.

RESULTS

Homocysteine was elevated in homocysteine groups versus controls except in estradiol-treated group. Intimal hyperplasia increased in placebo-treated ovariectomized homocysteine versus intact group. Exaggerated intimal hyperplasia in placebo-treated ovariectomized homocysteine was reduced by estrogen and so was homocysteine. Estrogen replacement in ovariectomized homocysteine group reduced intimal hyperplasia to that of intact or ovariectomized controls.

CONCLUSION

Estradiol treatment in this ovariectomized hyperhomocysteinemia carotid endarterectomy and resultant attenuation of homocysteine and neointima may have relevance to the beneficial effects of estrogen on hyperplastic response.

Ketorolac improves graft patency after coronary artery bypass grafting: a propensity-matched analysis

BACKGROUND

The use of ketorolac, a potent cyclooxygenase-1 inhibitor, for analgesia after cardiac operations has been limited by concerns of increased cardiovascular events. However, a recent study found that its use after coronary artery bypass grafting was associated with improved survival.

METHODS

This was a retrospective study of patients who received coronary arteriograms for symptoms suggestive of recurrent ischemic heart disease. Patients who received postoperative ketorolac were matched with nonusers by propensity scores. Graft occlusion rates were compared, and their association with ketorolac use was compared using Cox proportional hazard modeling.

RESULTS

Although the rate of graft occlusion was similar in the two groups, in 184 of the 303 propensity-matched patients (61%) who received ketorolac vs 202 of the 303 patients (67%) who did not (p=0.13), there was a longer time to angiographically proven occlusion in the patients who received ketorolac (2.80±2.19 vs 2.04±1.63 years; p<0.001). Cox modeling to control for the other variables and the longer time to angiography in the ketorolac group showed that ketorolac use was associated with nearly a halving of the hazard ratio (0.561; 95% confidence interval, 0.454 to 0.692; p<0.001) for any graft occlusion.

CONCLUSIONS

The use of ketorolac after coronary artery bypass grafting was associated with a lower rate of angiographically proven graft closure and suggests a mechanistic (improved graft patency) explanation for the previously reported survival benefit of ketorolac.

The effects of acarbose treatment on intimal hyperplasia in a rat carotid endarterectomy model of diet-induced insulin resistance

BACKGROUND

Increased carotid restenosis due to revascularization therapy is associated with insulin resistance. We hypothesize that glucose control using acarbose may attenuate intimal hyperplasia in rat carotid endarterectomy model of diet-induced insulin resistance.

METHODS

Rats were fed low-fat complex carbohydrate (control) or high-fat sucrose (insulin resistance) for 4 months. Three days preoperatively, some high-fat-sucrose rats were on acarbose, remainder of the rats received placebo. Rat carotids were assessed with duplex pre-and postoperatively. Acarbose and placebo continued for 2 weeks. Glucose, insulin, blood flow velocities and intimal hyperplasia were determined.

RESULTS

High-fat sucrose plus acarbose attenuated intimal hyperplasia. Post-drug high-fat sucrose glucose decreased. Blood flow velocities postoperatively elevated above baseline. High-fat sucrose increased blood flow velocities postoperatively, which was attenuated with acarbose.

CONCLUSION

Glucose control by acarbose in rat carotid endarterectomy model of diet-induced insulin resistance resulted in attenuation of intimal hyperplasia.