Cardiac catheterizations are done by inserting a thin wire through an artery in the groin or arm and threading the wire into a coronary artery. The coronary arteries are the arteries that supply the heart muscle with blood. This procedure allows a physician to perform diagnostic tests and also do procedures to treat blocked arteries. Mortality from heart catheterization is 0.1 to 0.2 percent, according to the Merck Manual. This is a common procedure but can have complications.
Arrythmias
Arrhythmias are the onset of irregular heartbeats, some of which can be fatal. Cardiac catheterization requires the use of contrast dye in order to delineate the coronary arteries. This dye can sometimes cause bradycardia, or slowing of the heart rate, when large amounts are used. Tachycardia, or fast-beating heart, may be accompanied by nausea and vomiting after injection of the dye. Tachycardia and bradycardia are simple arrhythmias to care for. Occasionally the wire “tickles” the heart and causes it to go into ventricular fibrillation. This is a fatal rhythm if not treated immediately. The heart goes into chaotic contractions that are asynchronous and do not pump blood from the heart. Treatment of this rhythm requires using the paddles and shocking the heart back into rhythm
Renal Failure
Contrast dye can affect the kidneys and cause contrast-induced nephropathy or kidney failure. This is a rare occurrence and is more likely in patients who have pre-existing kidney disease. Patients with known kidney disease are usually hydrated prior to the procedure with intravenous normal saline and medication to protect the kidneys. A study published by the American College of Cardiology in 2004 notes that contrast-induced nephropathy can occur even in the presence of normal renal function. They hypothesize that having a heart attack drops the blood pressure and produces unrecognized kidney damage. The damage is accentuated when contrast dye is given. Mortality in their series was 31 percent for those who had contrast-induced nephropathy.
Heart Attack
A heart attack occurs when a coronary artery is blocked and blood flow cannot get to the heart muscle. During cardiac catheterization, a piece of plaque can be broken off from the artery wall and lodged into a smaller branch of the artery, causing complete blockage and a heart attack. The National Heart Lung and Blood Institute states that the risks of cardiac catheterization are higher if the patient has diabetes, kidney disease or is 75 years or older. They also note that complications are greater in women and those having a cardiac catheterization on an emergency basis.
References
- The Merck Manual Online Library.com: Cardiac Catheterization: Cardiovascular Tests and Procedures
- Journal of the American College of Cardiology.org: Contrast Induced Nephropathy in patients undergoing primary angioplasty for acute myocardial infarction.
- The National Heart Lung and Blood Institute.org: Risks and Complications of Cardiac Catheterizations.
