I will be having a colonoscopy along with a gastroscopy and am nervous because I have mitral valve prolapse. Is this procedure dangerous for someone with this heart condition? Louise

Both colonoscopy and gastroscopy, also known as esophagogastroduodenoscopy (EGD) or upper endoscopy, are very safe diagnostic endoscopic procedures. Complications rarely occur, and when they do, they are most often related to sedatives or other medications given for the procedure. An extremely small percentage of patients suffer serious complications, such as perforation of the bowel.

That said, one important factor that a doctor should consider before ordering an endoscopic procedure is whether the patient should be given antibiotics ahead of time. Antibiotics can help prevent a potentially serious complication known as endocarditis -- an infection of the heart valves. Although the risk of an endoscopic procedure causing endocarditis is incredibly small, it is recommended that certain patients receive antibiotics as a precaution.

Generally, doctors base their decision on whether to give antibiotics on both the type of procedure being done and a patient's underlying heart condition. Thus, a procedure in which the chance of bacteria entering the bloodstream is high is more likely to require antibiotics. These high-risk procedures include gastroscopy in which the esophagus is dilated or in which a needle is used to deliver an injection into the lining of the esophagus. Patients at high-risk of endocarditis include those who have had the condition in the past, those who have had their heart valves replaced and those who have recently received vascular grafts. Most patients do not fall into this category.

Lower-risk conditions for endocarditis include mitral valve prolapse and other congenital heart conditions. In such cases, antibiotics may be given at the discretion of the endoscopist if a high-risk procedure is being done. Similarly, antibiotics may also be given if a lower-risk procedure (such as a routine upper endoscopy or colonoscopy) is done in a high-risk patient.

Generally, you should discuss your condition with the endoscopist before the procedure and find out if he plans to give you antibiotics. As far as the bowel-cleansing prep required before colonoscopy, it should pose no problem in someone with mitral valve prolapse. Most patients drink the Golytely cleansing solution and tolerate it well. However, another solution, called Fleet's Phospho-Soda, must be used with caution in patients with significant kidney or heart disease.