1. Stent to Prevent Strokes Fails in Study, Surprising Researchers Sally Kalson, Pittsburgh Post- Gazette, September 7, 2011 GINA KOLATA NY Times, September 7, 2011 http://www.nytimes.com/2011/09/08/health/research/08stent.html?ref=health http://www.post-gazette.com/pg/11250/1172625-149.stm NEJM Source

2. Study Fails A promising but expensive device to prop open blocked arteries in the brain in the hope of preventing disabling or fatal strokes failed in a rigorous study, researchers reported on Wednesday. Those who got the device actually had so many more strokes than those assigned to simply control risk factors, like blood pressure, cholesterol and diabetes, that the study was abruptly terminated.

3. How it started Boston Scientific made a small wire cage, a stent, to hold blocked brain arteries open, similar to those cardiologists use to open blocked vessels leading to the heart.stent According to the National Institute of Neurological Disorders and Stroke, as many as 55,000 of the 795,000 strokes that occur each year are caused by blockages in brain arteries. Soon doctors, desperate to help patients with severe blockages, started to use the new stent. The Food and Drug Administration approved it in August 2005, on the basis of a study with 45 patients who had had both a stroke and a blocked artery. The study was a registry study — one that had no control group that, for comparison, did not get the stent. It found a 4.4 percent stroke rate in the first month, much better than expected without the device.

4. Humanitarian Device Exemption The approval was on the basis of a humanitarian device exemption, which allows the agency to approve devices that would benefit fewer than 4,000 patients without requiring evidence that the device is effective, only that it is not overly risky. Private insurance often paid the more than $21,000 for the stent and its insertion in the brain, a price that did not include a stay in intensive care after the procedure. Many patients had private insurance because they were too young for Medicare. The average age of patients in the new study was about 60.Medicare Medicare wouldn’t pay for it.

5. Results Due to the nature of the approval, researchers could recruit patients for a study that randomly assigned them to receive the device and intensive medical management, which consists of a vigorous effort to control their risk factors, or to have intense medical management alone. The study’s results, which was scheduled to be published online Wednesday in The New England Journal of Medicine, were sobering. The stroke rate in the first month among patients who got the stent was 14.7 percent, or 33 patients. Five patients, or 2.2 percent, died. Among those who had medical therapy, 5.8 percent, or 13 patients, had strokes in the first month. One person died, but not from a stroke.New England Journal of Medicine

6. Hazard Function Analysis Significance level of difference

7. The Economics Marginal Benefits v. marginal cost. This is obvious with regular goods that are freely accessible, but less obvious with medical goods. Utilization MB, MC MB MC U1U1 U2?U2?