Primary pulmonary hypertension is a rare, often fatal disease that tends to occur with particular frequency in women during their third or fourth decade. 1 , 2 The factors leading to its development remain enigmatic. The occurrence of familial primary pulmonary hypertension suggests a genetic susceptibility. 3 Reports have also suggested that portal hypertension 4 , 5 and recent pregnancy 6 may have causative roles. Exogenous factors have been suspected as well, including cocaine use, 7 infection with the human immunodeficiency virus (HIV), 8 oral-contraceptive use, 9 , 10 and the use of anorexic agents. 11 – 13 In the 1960s, there was an epidemic of primary pulmonary hypertension in Switzerland, Germany, . . .
Since the early 1970's, bioabsorbable polymers have been used increasingly as suture and device materials. More than just a drug-carrying coating, some of these products are meant to degrade and disappear completely over time. In orthopedic reconstructive surgery, for example bioabsorbable screws have replaced some metallic screws, while in urology, bioabsorbable and biodegradable stents have been available for several years. Current coronary stent technology, including drug-eluting stents, relies on a metal scaffold that remains in the vessel indefinitely. However, evidence suggests that such permanent implants remain well beyond the time required for the prosthesis to accomplish its main goals of sealing dissection and preventing wall recoil. Investigators have been working to develop a bioabsorble coronary stent that will do its job and then slowly disappear, avoiding the irritation, chronic inflammation, and intimal hyperplasia associated with permanent mental stents. After eight years of animal studies, European investigators report evaluating a bioabsorbable stent in 20 patients with critical lower-limb ischemia. The BIOTRONIK Absorbable Metal Stent (AMS) (BIOTRONIK, Bulach, Switzerland, and Berlin, Germany) is a magnesium alloy stent that undergoes degradation over a 2-to 3-month period after deployment. Preliminary data have been published with follow-up data presented at several medical meetings, including 1-year data at the 17th Annual International Symposium of Endovascular Therapy in January 2005. The primary patency rate was 72.4% and the limb salvage rate was 94.7% in this very compromised population. With proof of concept established, a multicenter randomized trial in this setting is underway to determine safety and efficacy. The trial is comparing the absorbable metal stent in the coronary arteries of 19 patients. There are a number of potential advantages and disadvantages to bioabsorbable stents. This article reviews the initial experience with a bioabsorbable magnesium stent and discusses future directions.