For years, scientists like Hanjoong Jo have been telling us that blood vessels are like rivers and streams. Fluid dynamics are important; the patterns of curvature and current influence where sediment — or atherosclerosis — builds up.
One of the biggest possible perturbations of fluid dynamics in a blood vessel would be to stick a metal tube into it. Of course, cardiologists do this all the time.Â During percutaneous coronary intervention (PCI), doctors place a stent, basically a metal tube, inside a blood vessel to relieve an obstruction and restore blood flow to the heart muscle.
Habib Samady, Emory Healthcareâ€™s director of interventional cardiology, is leading a clinical trial looking at the effects of stent introduction on blood vessels that are not straight, but curved or angulated. To be eligible for the study, the patient’s blocked vessel has to bend more than 30 degrees. The study will look at patients who have undergone PCI for a heart attack and follow them over the course of a year. Less â€œdisturbed flowâ€ should mean better heart healing for the patient down the road.Â The study uses OCT (optical coherence tomography) and IVUS (intravascular ultrasound) to monitor the blood vessel and see how healing is affected by fluid dynamics after stent placement. Read more
Diabetes and heart disease often intersect. Emory cardiologist Aloke Finn and his colleagues recently had two papers in the Journal of the American College of Cardiology and in Atherosclerosis describing a possible interaction between the widely used diabetes drug metformin and drug-eluting stents, which are used to to treat coronary artery disease. Anwer Habib, MD is the first author of both papers.
The stent props the once-blocked artery open while the drugs in the stents are supposed to prevent the artery from becoming blocked again. The drugs — usually mTOR inhibitors such as http://www.magliettedacalcioit.com everolimus or the newer zotarolimus — slow down cell growth, but this cuts both ways. The drugs slow down the recovery of the lining of the blood vessel and this may contribute to blood clot formation after stent placement.
In cultured human cells and in rabbits with implanted stents, Finn and colleagues showed that metformin augmented the effect of mTOR inhibitors on regrowth of the blood vessel lining. (However — the authors acknowledge that their animal model was not diabetic or atherosclerotic.)
The findings could mean that people taking metformin would need to take medications to prevent blood clotting medications for a longer time after stent placement. The authors say that clinical studies following patients who receive drug-eluting stents should look at metformin’s effects on blood clotting events. A study examining drug eluting stents in diabetic patients is in the works at Emory.