There is one main, relatively rare complication associated with balloon angioplasty: abrupt vessel closure. Abrupt vessel closure occurs when the vessel that was treated becomes blocked. It typically strikes within 24 hours of the procedure, often within 15 minutes of the final balloon inflation while the patient is still in the catheter laboratory. If it does occur, emergency bypass surgery may be appropriate. However, the risk of this complication is reduced if a stent is also implanted during the angioplasty.

Other rare complications, usually resulting from an abrupt vessel closure event, include:  

• Heart attack
• Sudden cardiac death
• Stroke
• Injury of the access artery

It should be noted that the need for emergency bypass surgery following the angioplasty ranges from 2 to 5 percent with balloon angioplasty to approximately 0.5 percent with stent placement.

The other significant risk associated with balloon angioplasty is the development of blood clots. The combination of aspirin and clopidogrel, a type of antiplatelet, has shown to significantly reduce the risk of blood clots when taken for up to one year following angioplasty. Moreover, studies have shown additional benefit if this regimen is begun one to three days prior to the procedure itself. Other types of stents and coatings are currently being studied to prevent the formation of blood clots (and renarrowing of the artery) following stent placement during angioplasty.

Finally, there is also the risk of restenosis, or reclosure of the artery. The use of stents has helped reduce the restenosis rate, but it is still a relatively common occurrence. Older, bare-metal stents have a restenosis rate of about 50 percent, while the newer drug-eluting stents have a restenosis rate of less than 15 percent. Studies have shown that restenosis often occurs when the plaque buildup returns at either end of the stent, or if no stent was used, at the site of the original angioplasty. In these cases, a second angioplasty may be performed. If the coronary artery disease is widespread, however, the physician may recommend conventional coronary artery bypass graft surgery.

Drug-coated angioplasty balloons are presently being studied. If found safe and effective, these devices may eventually replace drug-coated stents as a means to prevent restenosis.