Complications
As technology and experience with cardiac catheterization has evolved, the risk of complications associated with the procedure has decreased. The complication rate varies based on diagnostic versus interventional use of catheterization (Table 4). Complications can range from minor issues with no longterm effects to major complications that require emergency care or surgical intervention and can lead to irreversible damage or death. However, the risk of major complications is under 1%. Major complications may include myocardial infarction, cerebrovascular events/stroke, cardiac perforation, and cardiac arrhythmias. Patients with comorbid conditions such as left ventricular dysfunction, valvular heart disease, a prior CABG, congestive heart failure, and renal insufficiency are at higher risk of complications.
Local vascular complications are the most common type of complication associated with cardiac catheterization. They are also the single greatest source of morbidity. Some of these complications include vessel thrombosis, distal embolization, and bleeding. Vessel thrombosis and embolization usually occur when a piece of plaque or a clot imperceptibly breaks free after contact with the catheter. Poorly controlled bleeding at the entry site is associated with a poorly placed puncture, vessel lacerations, excess anticoagulant use, and unskillful technique with a closure device. This can lead to hemorrhage and hematoma formation, usually within 12 hours of the procedure, and may require surgical interventions and blood transfusions. Patients may also experience false aneurysms or arteriovenous fistulas that can appear days to weeks after the procedure and require surgical interventions.
While an important and required part of cardiac catheterization, the use of contrast can also lead to complications such as allergic or anaphylactic reactions and nephropathy in some patient populations. Those with penicillin, seafood, or atopic allergies or past reactions to contrast are at a higher risk for complications. Premedicating these patients with glucocorticoids, H1 antihistamines, and H2 antihistamines can decrease the risk of such complications. Additionally, ionic contrast should be avoided and replaced with low- or iso-osmolar nonionic contrast.
Certain patient populations may also experience contrast-related nephropathy, including those with a history of diabetes, renal failure, and volume depletion. Patients who receive larger volumes of contrast are also at increased risk for nephrotoxicity. These patients should receive IV hydration pre- and postprocedure, and the amount of contrast used during the procedure should be minimized. Serum creatinine should be monitored in these patients for 3 to 5 days after catheterization. n-acetylcysteine can also be administered pre- and postprocedure as a protective strategy; however, clinical studies show questionable value.