Leg Swelling after Gene Therapy for Peripheral Vascular Disease FREE

Peripheral vascular disease refers to a narrowing of the blood vessels in the extremities, typically the legs and feet, which leads to lack of adequate blood supply. Patients with moderate peripheral vascular disease develop leg and foot pain during activity, a condition called claudication. When the disease is more severe, patients experience pain even without exercise, a condition known as pain at rest. When the disease is most severe, tissues that do not get enough blood can die, and the patient develops sores on the leg or foot (ischemic ulcers or gangrene). A new experimental therapy for peripheral vascular disease involves injecting patients with a gene that allows cells to produce vascular endothelial growth factor, a substance that helps tiny new blood vessels to grow. Some researchers have noticed that patients who get this kind of gene therapy develop the complication of swelling in their legs.

To learn how often patients who get gene therapy for peripheral vascular disease develop leg swelling, and to see which types of patients are most likely to develop swelling.

The researchers studied 90 patients with peripheral vascular disease who were given gene therapy with vascular endothelial growth factor. Of these patients, 28 had only claudication and the others had more severe disease. Of the 90 patients, 40 had the gene therapy injected directly into the blood vessels in the leg and 50 had the therapy injected into the leg muscle.

The researchers examined the patients repeatedly for 4 weeks after they got the gene therapy. They noted whether swelling developed, and if so, when it occurred and how severe it was.

Of the 90 patients, 31 developed leg swelling during the month after therapy. Swelling was less common in patients who had only claudication than in those who had pain at rest, and it was more common in patients who had tissue damage. A brief course of diuretics (“water pills”) was useful in treating the swelling, and no patient developed a serious complication related to the swelling.

This study had no comparison group of patients who had peripheral vascular disease but did not get gene therapy. It therefore cannot tell us for certain that the swelling was a result of the gene therapy rather than of the disease itself.

Patients who receive the vascular endothelial growth factor gene to treat peripheral vascular disease may develop leg swelling. The swelling appears to be most common in patients who have more severe peripheral vascular disease and can generally be treated successfully with diuretics.