COMMONLY PERFORMED AND HIGHLY accurate, diagnostic cardiac catheterization reveals defects in the heart chambers, the valves, and coronary arteries. Using fluoroscopy, the cardiologist inserts catheters into one or both sides of the heart and measures pressures and cardiac output. The cardiologist also may obtain blood specimens for oxygen saturation testing. By injecting contrast media, the cardiologist can further define cardiac structures, including the coronary arteries, and assess cardiac wall motion. Depending on the facility and the patient's condition, cardiac catheterization may be performed as either an inpatient or an outpatient procedure.
Indications for cardiac catheterization include definitive or suspected myocardial ischemia, syncope, valvular heart disease, and acute myocardial infarction (MI). It also may be indicated after an MI, coronary artery bypass graft surgery, or percutaneous transluminal coronary angioplasty in patients having recurring symptoms, and after a heart transplant to monitor for rejection.
To prepare the patient, teach him about the procedure and answer his questions. Provide booklets, videos, or other educational tools to reinforce learning. The cardiologist will discuss benefits and risks, such as dysrhythmias, bleeding, stroke, or MI. Make sure the patient has provided informed consent.
Assess for allergies, especially significant allergies such as a previous anaphylactic reaction to one or more allergens, including contrast media. Ask if he has a history of asthma, which is associated with an increased likelihood of a contrast reaction. Also note if he's allergic to medications—including lidocaine, the local anesthetic commonly used for vascular access.
The patient may be instructed to fast for 3 to 8 hours before the procedure and withhold or decrease the dosages of scheduled medications (including insulin, antihypertensive drugs, and diuretics). The physician may prescribe pretreatment prophylaxis for the patient with a history of contrast media allergy. Establish two peripheral venous access sites and infuse I.V. fluids as ordered to prevent dehydration. Obtain specimens for lab tests (complete blood cell count, electrolytes, blood urea nitrogen, creatinine, coagulation studies, cardiac biomarkers, and urinalysis). Also obtain a chest X-ray and an ECG.
The femoral and brachial arteries are common catheter insertion sites, although the radial artery also is an option. Assess and mark pulses on the extremity that will be used. Have the patient void. (He may wear his dentures and eyeglasses during the test.) Administer analgesics and sedatives as directed.
During the procedure
The test itself lasts 30 minutes to 1 hour, but the entire procedure, including precatheterization and postcatheterization care, may take up to 4 hours. Tell the patient what to expect, including the following points:
* He'll receive I.V. medication for anxiety and pain as needed throughout the procedure.
* The testing takes place in a cool, darkened room. He'll lie on a special procedure table where X-rays can be taken, either by repositioning the table or by moving the X-ray machine around him. He'll be attached to equipment for continuous cardiac, BP, and pulse oximetry monitoring.
* He'll be awake throughout the procedure and may be asked to cough or take a deep breath at certain times. Tell him to immediately report any unusual symptoms, such as chest discomfort or trouble breathing.
* When contrast media is injected into the left ventricle, he may feel warm or flushed for up to a minute.
* After the test, the catheters are removed and bleeding is controlled with direct pressure or with a vascular closure device. He'll be continuously assessed and monitored in a postcardiac catheterization recovery area. Depending on his condition and the method used to stop bleeding, he'll spend some time on bed rest with the affected extremity immobilized.
Assess the patient for nausea or pain (including back pain from lying still) and provide medication as indicated. Assess the catheter insertion site for bleeding or hematoma with vital signs as ordered. Instruct him to inform you immediately if he experiences chest discomfort or other anginal symptoms. Review the discharge orders with the patient and family, including activity restrictions, and educate them about signs and symptoms of complications, including MI, stroke, and insertion-site bleeding or infection. If indicated, inform the patient that he may need blood urea nitrogen and creatinine monitoring after discharge. Finally, instruct him to follow up with his primary care provider.