Chapter 2 The Cardiac Catheterization Laboratory
CATHETERIZATION LABORATORY FACILITIES
Room Setup/Design/Equipment
The setup and design for the cardiac catheterization laboratory vary from a single room, as seen in a mobile catheterization laboratory or a small community hospital, to a multilaboratory facility, as is found in large tertiary care centers (Box 2-1). In these facilities with multiple laboratories, a central work area is needed to coordinate patient flow to each of the surrounding laboratories and for centralized equipment storage. Patient holding areas are used for observation and evaluation of patients before and after the procedure.
Physician Credentialing
The more experience an operator has with a particular procedure, the more likely this procedure will have a good outcome. The American College of Cardiology Task Force has established guidelines for the volume of individual operators in addition to the facility volumes mentioned earlier. The current recommendations for competence in diagnostic cardiac catheterization require a fellow perform a minimum of 300 angiographic procedures, with at least 200 catheterizations as the primary operator, during his or her training.1
PATIENT SELECTION FOR CATHETERIZATION
Indications for Cardiac Catheterization in the Adult Patient
Table 2-1 lists generally agreed on indications for cardiac catheterization. With respect to CAD, approximately 15% of the adult population studied will have normal coronary arteries. Coronary angiography is, for the moment, still consideredthe gold standard for defining CAD. With advances in magnetic resonance imaging and multislice computed tomography, the next decade may well see a further evolution of the catheterization laboratory to an interventional suite with fewer diagnostic responsibilities.
Table 2-1 Indications for Diagnostic Catheterization in the Adult Patient
Coronary Artery Disease |
Symptoms |
Unstable angina |
Postinfarction angina |
Angina refractory to medications |
Typical chest pain with negative diagnostic testing |
History of sudden death |
Diagnostic Testing |
Strongly positive exercise tolerance test |
Early positive, ischemia in > 5 leads, hypotension, ischemia present for > 6 minutes of recovery |
Positive exercise testing following after myocardial infarction |
Strongly positive nuclear myocardial perfusion test |
Increased lung uptake or ventricular dilation after stress |
Large single or multiple areas of ischemic myocardium |
Strongly positive stress echocardiographic study |
Decrease in overall ejection fraction or ventricular dilation with stress |
Large single area or multiple or large areas of new wall motion abnormalities |
Valvular Disease |
Symptoms |
Aortic stenosis with syncope, chest pain, or congestive heart failure |
Aortic insufficiency with progressive heart failure |
Mitral insufficiency or stenosis with progressive congestive heart failure symptoms |
Acute orthopnea/pulmonary edema after infarction with suspected acute mitral insufficiency |
Diagnostic Testing |
Progressive resting LV dysfunction with regurgitant lesion |
Decreased LV function and/or chamber dilation with exercise |
Adult Congenital Heart Disease |
Atrial Septal Defect |
Age > 50 with evidence of coronary artery diseaseSeptum primum or sinus venosus defects |
Ventricular Septal Defect |
Catheterization for definition of coronary anatomy |
Coarctation of the Aorta |
Detection of collateral vessels |
Coronary arteriography if increased age and/or risk factors are present |
Other |
Acute myocardial infarction therapy—consider primary PCI |
Mechanical complication after infarction |
Malignant cardiac arrhythmias |
Cardiac transplantation |
Pretransplant donor evaluation |
Post-transplant annual coronary artery graft rejection evaluation |
Unexplained congestive heart failure |
Research studies with institutional review board review and patient consent |
LV = left ventricular.
CARDIAC CATHETERIZATION PROCEDURE
Right-Sided Heart Catheterization
In the cardiac catheterization laboratory, right-sided heart catheterization is performed for diagnostic purposes. The routine use of right-sided heart catheterization during standard left-sided heart catheterization was studied by Hill and coworkers. Two hundred patients referred for only left-sided heart catheterization for suspected CAD underwent right-sided heart catheterization. This resulted in an additional 6 minutes of procedure time and 90 seconds of fluoroscopy. Abnormalities were detected in 35% of the patients. However, management was altered in only 1.5% of the patients. With this in mind, routine right-sided heart catheterization cannot be recommended. Box 2-2 outlines acceptable indications for right-sided heart catheterization during left-sided heart catheterization.
Diagnostic Catheterization Complications
Complications are related to multiple factors, but severity of disease is important. Mortality rates are shown in Table 2-2. Complications are specific for both right- and left-heart catheterization (Table 2-3). Although advances in technology continue, these complication rates are still present today, most likely due to the higher risk patient undergoing catheterization.
![image](/wp-content/uploads/2015/02/B9781416037866100026_table2-21.jpg)
Table 2-2 Cardiac Catheterization Mortality Data
Rights were not granted to include this table in electronic media. Please refer to the printed book.
From Pepine CJ, Allen HD, Bashore TM, et al: ACC/AHA guidelines for cardiac catheterization and cardiac catheterization laboratories. Circulation Nov, 84(5): 2213–2247
Definition of Pressure Waveforms—Cardiac Cycle
Right-Sided Heart Pressures
The right-sided heart pressures, as measured in the cardiac catheterization laboratory, consist of the central venous pressure (CVP) or right atrial (RA) pressure (RAP), right ventricular (RV) pressure (RVP), PAP, and PCWP. The CVP consists of three waves and two descents (Fig. 2-1, Box 2-3). The A wave occurs synchronously with the Q wave of the ECG and accompanies atrial contraction. Next, a smaller C wave appears, which results from tricuspid valve closure and bulging of the valve into the right atrium as the right ventricle begins to contract. After this, with the tricuspid valve in the closed position, the atrium relaxes, resulting in the X descent. This is followed by the V wave, which corresponds to RA filling that occurs during RV systole with a closed tricuspid valve. As the RV relaxes, the RVP then becomes less than the RAP, the tricuspid valve opens, and the atrial blood rapidly empties into the ventricle. This is signified by the Y descent.
Left-Sided Heart Pressures
The LA, LV, aortic, and peripheral pressures are commonly measured in the cardiac catheterization laboratory. The LAP can be measured directly if a transseptal catheter is placed. Because this is not commonly done, the PCWP is used to estimate LAP. The LAP has a very similar appearance (A, C, V waves; X, Y descent) to that in the RA, although the pressures seen are about 5 mm Hg higher. The A wave in the RA tracing is normally larger than the V wave whereas the opposite is true in the LA (or PCWP). The PCWP provides reasonable estimations of the LAP, although the waveform is often damped and also delayed in time compared with the LAP (Fig. 2-2).
LV pressure also has many similar characteristics to the RVP, although because this is a thick-walled chamber, the generated pressures are higher than those reached in the RV. The central aortic pressure displays a higher diastolic pressure than that seen in the ventricle due to the properties of resistance in the arterial tree and the presence of a competent aortic valve. The dicrotic notch, which signifies the aortic valve closure, is a prominent feature of the aortic pressure wave in the central aorta. As the site of pressure measurement moves more distally in the arterial tree, there is a progressive distortion of the arterial waveform, usually demonstrated as an increase in systolic pressure. This is thought to be due to the addition of the pressure wave of reflected waves from the elastic arterial wall. Summation of reflected pressure waves has been postulated as a contributing factor in aneurysm formation. Additionally, the rapid propagation of reflected waves along stiff arteries has been advanced as an explanation of the systolic hypertension seen in the elderly. Table 2-4 displays the range of normal pressures on the right and left side of the heart.
Valvular Pathology
Stenotic Lesions
Stated another way, for any given orifice size, the transvalvular pressure gradient is a function of the square of the transvalvular flow rate. For example, with mitral stenosis, as the valve area progressively decreases, a modest increase in the rate of flow across the valve causes progressively larger increases in the pressure gradient across the valve (Fig. 2-3).