St. Luke's Cardiac Catheterization Laboratory is one of the world's largest and most advanced cardiac cath labs in the world. Cardiologists and staff treat more than 10,000 patients annually and perform more than 15,000 procedures each year.
Diagnostic Procedures
A diagnostic procedure is performed in the cath lab to determine the extent of disease present in the vascular system. Left heart catheterization (arterial) is performed to determine blockages in the coronary vascular system. Right heart catheterization (venous) is performed to determine how well the heart valves are functioning and how effective the heart is pumping blood to the lungs.
During left heart catheterization a sheath (small flexible catheter) is inserted into the femoral or brachial artery. A heart catheter is then advanced through the sheath to the aortic arch and engaged in the ostium of the coronary artery to be visualized. There are two main coronary artery systems; the right and the left. Once the catheter is engaged, contrast (iodine based dye) is injected into the artery and visualized under fluoroscopy to detect blockages. During the left heart catheterization additional contrast may be injected to visualize the left ventricle, carotid, renal, and peripheral arteries. Pressure readings are taken at various sites to determine stenosis (narrowing of an artery) and valve function.
During right heart catheterization a sheath is inserted into the femoral or brachial vein. A catheter (usually a swan ganz catheter) is then advanced to the pulmonary artery via the right atrium and ventricle. Pressures readings and blood oxygen saturations are obtained from the different chambers to determine abnormalities. If significant abnormalities are noted a cardiac output study may be performed.
Prostin Studies are performed to diagnose pulmonary hypertension in heart transplant candidates. Due to frequent occurrence of right ventricular failure, after cardiac transplantation caused by pulmonary hypertension, additional assessment is required to separate candidates with fixed increased pulmonary vascular resistance. A diagnostic right heart catheterization (pressure monitoring) with cardiac output measurements is performed prior to prostin infusion. If the pressure readings meet predetermined criteria, the prostin infusion is then started. Following infusion repeat cardiac output measurements and pulmonary pressure readings are obtained to determine response to the prostin infusion.
Ergonovine Testing is a diagnostic test to induce coronary artery spasm. Patients suspected of prinzmetal angina/variant angina are candidates for this test. Prior to injection of ergonovine a left heart catheterization is performed. Incremental doses of ergonovine are given via peripheral IV. After each incremental dose the patient is assessed for nausea, headache, angina, EKG changes and increased blood pressure. Angiography of the coronary artery is preformed after positive results or after five minutes. If the patient experiences a positive result, Nitroglycerine is administered directly into the coronary artery to reduce spasm.
A right heart biopsy is performed either from the internal jugular or femoral vein. A sheath is first introduced in the vein and a swan ganz catheter is advanced to measure right heart pressures prior to obtaining biopsy specimens. After pressure readings are obtained a bioptome (tissue biting forceps) is advanced to the right ventricle and multiple specimens are obtained and sent to the pathology laboratory. During the procedure absolute care is taken not puncture the wall of the ventricle.
Electrophysiology Study (EPS) is the study or detailed analysis of normal and abnormal electrical conduction systems of the heart. The EP study enables the physician to assess the function of the SA node, AV node, and the His-Purkinje system. It can also help to evaluate the electrophysiologic properties such as automaticity, conduction velocity and refractoriness of the cardiac tissue. Conduction intervals are measured within the heart by means of intra-cardiac electrode catheters. From these measurements the doctor is able to identify problem areas of conduction. In a controlled clinical environment this test permits the electrophysiologist to study cardiac abnormalities and locate the cardiac activation and arrhythmia mechanism that are responsible for these abnormalities. The electrophysiology procedure is an invasive examination, similar to a heart catheterization that is performed by introducing electrode catheters into the right side of the heart via the femoral vein, brachial vein, or jugular vein. The catheters are positioned in the heart and then used to measure and record the activating sequence of the cardiac circuit.
Interventional Procedures
PTCA - Percutaneous Transluminal Coronary Angioplasty, or PTA (Percutaneous Peripheral Angioplasty) more commonly refered to as a "balloon" procedure is one of the most commonly known interventional cardiac procedures. This procedure has been used to open coronary arteries for over 20 years. Cardiologists have seen many changes in techniques for accomplishing the procedure over the past years but the basic procedure has not changed. A catheter with a balloon on the end is inflated at the blockage inside the artery to "push" the plaque against the artery walls and allow the blood to flow normally.
A stent is a small stainless steel tube that is permanently placed inside an artery to keep it open. Stents can be placed inside many different arteries. Stents can be used to open the coronary arteries, arteries in the leg, kidney, neck (carotid), or other peripheral arteries. Stents are mounted on the top of a balloon catheter and then pushed through the blockage. The balloon is then inflated and the stent expanded pressing against the artery wall. The balloon is then deflated and removed leaving the vessel lumen held open by the stent. Some stents are self-expanding and are deployed without the aid of a balloon catheter.
Atherectomy - In this procedure, the plaque is actually "removed" from the inside of the blocked artery. There are three different types of atherectomies.
- Extraction - The catheter is placed at the beginning of the blockage. The catheter tip rotates, cuts, and vacuums the blockage out of the body. The procedure may be repeated several times before the blockage is sufficiently reduced. This procedure is commonly referred to as a TEC Atherectomy.
Directional - The catheter shaves the plaque from the inside of the artery. The catheter is then removed and the plaque removed from inside the catheter tip (cutting device). Directional atherectomy is used to removed plaque that is only on one side of the artery rather then all the way around the inside of the artery. This procedure is commonly referred to as a DVI Atherectomy.
- Rotational Ablation - A small drill (burr) turns quickly to cut through plaque that is very hard. The hard plaque is cut into very fine particles that are eliminated by the body. This procedure is commonly referred to as a Rotoblator Atherectomy.
Permanent Pacemaker - Pacemaker procedures are done for many different reasons. The basic indication for pacemaker implantation is that there is some defect in the electrical conduction system in the heart. The patient may be experiencing a slow heart rate, an erratic heart rate, an irregular beating of the atrium and ventricle, or several other abnormalities. Many different types of pacemaker are used to treat the various conditions. The procedure is usually performed from the left or right subclavian vein approach. Wire(s) are placed in the right atrium and/or right ventricle via the subclavian vein and then an analyzer is connected to the leads to confirm proper positioning and conduction. After lead placement a small generator is connected to the wire(s) and permanently placed just under the skin in the subclavian area. Special post-operative precautions must be taken to ensure that lead placement is maintained.
Pacemaker Lead Extraction - Occasionally pacemaker leads must be removed. Most of the time new leads are inserted without removal of the malfunctioning lead. Most often, the pacemaker leads malfunction due to a fracture (break) of the lead which results in failure to adequately conduct electrical impulses. Pacemaker leads may need to be removed because of sepsis or because the patient has already had additional leads implanted and there is just not enough area in the vessel to accommodate additional leads. Special extraction equipment is used to tunnel over the old lead and then remove (pull) the damaged leads through the tunneling device. This procedure is done under general anesthesia.
Cardioversion - Synchronized cardioversion is an electrical shock applied to the chest to momentarily stop the heart so that normal sinus rhythm may take over. Conditions that warrant cardioversion are atrial fibrillation, atrial flutter, PSVT, and stable ventricular tachycardia. Sedation is given just prior to delivering the external electrical shock to produce an amnesic effect post procedure. Cardioversions are done in a controlled environment by appropriately trained nursing staff and a physician. Cardioversions are frequently done in the CCU, ER, or outpatient areas as long as facilities are appropriately equipped to monitor the patient.
Venacava Filter Placement (IVC filter) - Venacava filters are placed in the inferior vena cava for only one reason; to prevent thrombus from traveling through the venous system back to the heart and lungs. IVC filters are delivered into the inferior vena cava via the femoral or jugular vein. The procedure may be done in the X-Ray Department or the Cath Lab under fluoroscopy. Once the filter is deployed in the inferior vena cava it can never be removed. Patient must continue on anticoagulation therapy post procedure.
Valvuloplasty is a procedure that is performed with a large balloon to stretch open a value. The value is stretched open by the balloon for only a few seconds at a time and then pressure readings and angiogram are taken to determine the status of the value function. Not all patients with valvular stenosis are candidates for valvuloplasty. Most patients with valvular stenosis are taken to the operating room for replacement of the stenotic value. Valvuloplasty is most commonly used on the aortic or mitral values but can be done on any valve in the heart.
