Air Pollution and CVD Risks: The Beijing Olympics Challenge
As the 2008 Olympic games approach, more and more countries are getting concerned about the consequences of Beijing’s air quality on the health of their athletes. And rightly so. Results of recent studies indicate that the magnitude of the effects of fine particulate pollution on the general population may be actually larger than previously thought.
In the February issue of NEJM (vol. 356. pp. 447-458), Miller et al. presented the results of a large, prospective cohort study (N=65,893) in postmenopausal American women exposed to particles with diameters smaller than 2.5 µm (PM2.5). The median follow-up period was 6 years. They report that with each increase of 10 µg PM2.5 per cubic meter of air, there is a 24% increase in the risk of a cardiovascular event and a 76% increase in the risk of death from cardiovascular disease. What is also alarming is that these risks increase with increasing BMI.
A more recent report from a German prospective study by Hoffman et al. (Circulation, vol. 116:489-496) linked traffic-generated fine particles to coronary artery calcification – within just a period of 5 years. Although this study is relatively smaller (N=4494), study subjects included both sexes with a wider age range of 45 to 74 years.
The US Environmental Protection Agency set health standards on air pollution way back in 1997 but only managed to finalize its Clean Air Fine Particle Implementation Rules this year. China and Beijing promise to achieve more than that in less than a year. Can they deliver?
Photo credit: http://www.terradaily.com/news/pollution-05zr.html
Can DES Survive? The fate of drug-eluting stents
The sales of drug-eluting stents (DES) continue to fall as the controversy of their benefits and safety rages on. DES used to be the rave of in percutaneous coronary intervention (PCI). Since the approval of Cordis CYPHER™ sirolimus-eluting stent in 2003, followed by TAXUS™ paclitaxel-eluting stent a year later, DES have raked in billions of dollars for the pharmaceutical industry in the last 3 years.
Then came the bad news in 2006, when DES came under attack during the World Congress of Cardiology in Barcelona as reports of late stent thrombosis and myocardial infarction trickled in. The COURAGE (NJEM Vol. 356:1503-1516) trial also put doubts on the benefits of DES over mainstream medical therapy.Will DES survive this? Or will it go the way of LYMErex™?* The most recent report on DES from a Danish trial is encouraging. According to Jensen et al. (JACC Vol. 50:463-470), “the minor risk of ST and MI within 15 months after implantation of DES seems unlikely to outweigh the benefit of these stents.”
However, DES sales worldwide continue to decline and doctors are opting back to bare metal stents. Unless the next generation of DES shows better efficacy and safety profiles, the DES era may actually be over.
*Note: LYMErex™ was the vaccine against Lyme borreliosis approved by FDA in 1998. A class action suit due to safety issues was filed in 1999. In the end, Lymerex was cleared but the damage was done. Sales never picked again and the product was withdrawn from the market in 2002 due to lack of demand.