Cardiac Catheterization

Definition

Cardiac catheterization involves passing a catheter into the right or left side of the heart. Catheterization can determineblood pressure and blood flow in the chambers of the heart, permits blood sample collection, and record films of the heart’s ventricles (contrast ventriculography) or arteries (coronary arteriography or angiography).

Catheterization of the heart’s left side assesses the patency of the coronary arteries, mitral and aortic valve function, and left ventricular function. Catheterization of the heart’s right side assesses tricuspid and pulmonic valve function and pulmonary artery pressures.

Purpose of Cardiac Catheterization

• To evaluate valvular insufficiency or stenosis, septal defects, congenital anomalies, myocardial function, myocardial blood supply, and cardiac wall motion.
• To aid in diagnosing left ventricular enlargement, aortic root enlargement, ventricular aneurysms, and intracardiac shunts.

Procedure

Patient Preparation

1. Explain the procedure to the patient.
2. Tell him to restrict fluids for at least 6 hours before the test.
3. Inform him that the test takes 1 to 2 hours.
4. Tell him that he may receive a mild sedative but will remain conscious during the procedure.
5. Have the patient to void just before the procedure.
6. Check the patient history for hypersensitivity to shellfish, iodine, or contrast media used in other diagnostic tests. Discontinue any anticoagulant therapy as ordered.

Implementation

1. The patient is placed supine on padded table and his heart rate and rhythm, respiratory status, and blood pressure are monitored throughout the procedure.
2. An I.V. line is started, if not already in place, and a local anesthetic is injected at the insertion site.
3. A small incision is made into the artery or vein, depending on whether the test is for the left or right.
4. The catheter is passed through the sheath into the vessel and guided using fluoroscopy.
5. In the right-sided catheterization, the catheter is inserted into the antecubital or femoral vein and advanced through the vena cava into the right side of the heart and into the pulmonary artery.
6. If left-sided heart catheterization, the catheter is inserted into the brachial or femoral artery and advanced retrograde through the aorta into the coronary artery ostium and left ventricle.
7. When the catheter is in place, contrast medium is injected to make visible the cardiac vessels and structures.
8. Nitroglycerin is given to eliminate catheter-induced spasm or watch its effect on the coronary arteries.
9. After the catheter is removed, direct pressure is applied to the incision site until bleeding stops, and a sterile dressing is applied.

Nursing Interventions

1. Monitor the patient’s heart rate and rhythm, respiratory and pulse rates, and blood pressure frequently.
2. Monitor the patient’s vital signs every 15 minutes for 2 hours after the procedure, every 30 minutes for the next 2 hours, and then every hour for 2 hours.
3. If no hematoma or other problems arise, begin monitoring every 4 hours. If vital signs are unstable, check every 5 minutes and notify the practitioner.
4. Observe the insertion site for a hematoma or blood loss. Additional compression may be necessary to control bleeding.
5. Check the patient’s color, skin temperature, and peripheral pulse below the puncture site.
6. Enforce bed rest for 8 hours. If the femoral route was used for catheter insertion, keep the patient’s leg extended for 6 to 8 hours.
7. If medications were withheld before the test, check with the practiotner about resuming their administration.
8. Administer prescribed analgesics.
9. Make sure a posttest ECG is scheduled to check for possible myocardial damage.

Interpretation

Normal Results

• No abnormalities of heart valves, chamber size, pressures, configuration, wall motion, or thickness, and blood flow.
• Coronary arteries have a smooth and regular outline.

Abnormal Results

• Coronary artery narrowing greater than 70% suggests significant coronary artery disease.
• Narrowing of the left main coronary artery and occlusion or narrowing high in the left anterior descending artery suggests the need for revascularization surgery.
• Impaired wall motion suggests myocardial incompetence.
• A pressure gradient indicates valvular heart disease.
• Retrograde flow of the contrast medium across a valve during systole indicates valvular incompetence.

Precautions

• Coagulopathy, impaired renal function, and debilitation usually contraindicate catheterization of both sides of the heart. Unless a temporary pacemaker is inserted to counteract induced ventricular asystole, left bundle-branch block contraindicates catheterization of the right side of the heart.
• If the patient has valvular heart disease, prophylactic antimicrobial therapy may be indicated to guard against subacute bacterial endocarditis.

Complications

• Ineffective endocarditis in a patient with vulvular heart disease.
• Myocardial infarction, arrhythmias, cardiac tamponade, pulmonary edema, hematoma, blood loss, adverse reaction to contrast media, and vasovagal response.