How effective are bioresorbable scaffolds to treat patients with coronary artery disease?

This study examined how effective bioresorbable scaffolds (BRS) were at preventing heart complications in patients with coronary artery disease (CAD). The study found that while BRS were somewhat effective, some patients still developed complications.

CAD is caused by the narrowing of blood vessels in the heart. Treatment for CAD often uses stents. These are scaffolds that are inserted into the narrowed blood vessels to keep them open. These can also slowly release drugs that stop the blood vessels from growing over them and narrowing again. 

Stents are made with metal and so there are concerns that they can cause long-term side effects. Bioresorbable scaffolds (BRS) do the same job as metal stents but dissolve after 3 years. Some clinical trials have shown that BRS are not as effective as metal stents. However, clinical trials do not always reflect the general population. Therefore, it is worth studying the safety and effectiveness of BRS in patients not part of a clinical trial.

Data from 1614 patients treated with BRS for CAD was examined. In total, 1817 BRS were inserted into the patients. Patients were followed for an average of 1228 days (over 3.3 years). Treatment failure was the main outcome measured. This was when patients had a heart attack or died due to the treated blood vessel or had to get the BRS redone. 

After 3 years, 17.1% of patients suffered from treatment failure and CAD became worse in 21.8% of patients. 7% of patients suffered from a heart attack in the treated blood vessel. 11.6% of patients had to have the BRS redone.

Several factors increased the risk of treatment failure. Older patients had an 18% higher risk of failure. Patients with diabetes had a 46% higher risk of failure. Patients with complex cases of narrow vessels had a 40% higher risk. Patients whose narrowed blood vessels were close to major blood vessels (bifurcation) had a 64% higher risk of failure. Patients who had a small BRS (2.5 mm) inserted had a 31% higher risk of failure.

Blood clotting, which can cause further complications, occurred in 2.6% of patients. Of these, 12.8% developed clots within 24 hours of having the BRS inserted. The majority of patients (33.3%) developed clots a year after treatment.

The authors concluded that BRS was effective for most patients, however, a significant number of patients experienced treatment failure. 

This study used medical records which means that not all information was available, such as other medications patients were taking. This study did not include a placebo or comparison treatment. Not all patients had imaging during BRS insertion which improves BRS placement in vessels.