14.17: Cardiac Catheterization III: Left Heart Catheterization

Left heart catheterization is an invasive diagnostic procedure used to evaluate the function and structure of the left side of the heart. It is generally performed to diagnose and treat cardiovascular conditions such as valve abnormalities, coronary artery disease, and congenital heart defects.

Diagnostic and therapeutic purposes

Left heart catheterization serves various diagnostic and therapeutic purposes, including:

• Assessing coronary artery bypass grafts.
• Evaluating coronary artery disease in patients with chest pain of uncertain origin.
• Determining the severity of myocardial or valvular disorders such as aortic stenosis, mitral stenosis, and cardiomyopathies.
• Assessing and treating cardiac arrhythmias.
• Treating valvular heart diseases through procedures such as valvuloplasty.

Contraindications

Relative contraindications for this procedure include:

• Severe uncontrolled hypertension.
• Sepsis.
• Unstable arrhythmias.
• Acute cerebrovascular accidents.
• Allergy to radiographic contrast.

Pre-procedure preparations

Before the procedure, several preparatory steps are crucial:

1. Discontinue oral anticoagulants at least 24 hours prior, based on creatinine clearance.
2. Take a thorough history with an emphasis on contrast allergy.
3. Examine the access site and document peripheral pulses.
4. Check hemoglobin, platelets, creatinine, and coagulation profile.
5. Obtain informed consent and explain the procedure's risks.
6. Administer IV normal saline to prevent contrast-induced renal dysfunction, especially in patients with renal issues.

Procedure

The procedure typically begins with selecting an access site, most commonly the femoral artery in the groin, though the brachial and radial arteries may also be used. The patient is placed supine, and access sites are sterilized and draped. Cannulas, needles, and catheters are flushed with heparinized saline.

A fine needle is inserted into the chosen artery, and a flexible guide wire is threaded through the needle. Once the guide wire is in place, a sheath is placed over it to facilitate catheter access. The catheter is then introduced through the sheath and navigated to the heart with fluoroscopic imaging. Fluoroscopy, a continuous X-ray imaging technique, allows the physician to visualize the movement and placement of the catheter in real-time, ensuring accurate navigation through the arterial system into the aorta and then into the left ventricle or coronary arteries, depending on the procedure's purpose.

Intra-cardiac pressures are measured during catheterization, and a contrast agent may be injected through the catheter to visualize the heart chambers and coronary arteries under fluoroscopy. This imaging is crucial for identifying heart blockages, abnormalities, or structural issues. If significant blockages or abnormalities are detected, interventional procedures such as angioplasty or stent placement can be performed under fluoroscopic guidance.

Post-procedure care

Upon completion, the catheter and sheath are carefully removed, and pressure is applied to the access site to prevent bleeding. A closure device may be used to seal the puncture site, particularly for femoral access. The patient is then monitored for any complications, such as arrhythmias, myocardial infarction, bleeding, hematoma, perforation of the left heart, great vessels, or systemic embolization.

Conclusion

Understanding the access site selection, the catheter insertion procedure, and the role of fluoroscopy is essential to performing left heart catheterization safely and effectively, minimizing risks, and optimizing patient outcomes.