Introduction to the Catheterization Laboratory

1 Introduction to the Catheterization Laboratory



Cardiac catheterization is the insertion and passage of small plastic tubes (catheters) into arteries and veins to the heart to obtain x-ray pictures (angiography) of coronary arteries and cardiac chambers and to measure pressures in the heart (hemodynamics). The cardiac catheterization laboratory performs angiography to obtain images not only to diagnose coronary artery disease but also to look for diseases of the aorta and pulmonary and peripheral vessels. In addition to providing diagnostic information, the cardiac catheterization laboratory performs catheter-based interventions (e.g., angioplasty and stents, now called percutaneous coronary intervention [PCI]) or catheter-based treatments of structural heart disease for both acute and chronic cardiovascular illness. Table 1-1 lists procedures that can be performed with coronary angiography. Figure 1-1 shows common access routes for cardiac catheterization.


Table 1-1 Procedures That May Accompany Coronary Angiography










































Procedure Comment

Used as IV access for emergency medications (femoral, internal jugular, subclavian) or fluids, temporary pacemaker (pacemaker not mandatory for coronary angiography)

 

Routine for all studies (aorta, left ventricle)

Not routine for coronary artery disease; combined pressures; mandatory for valvular heart disease; routine for CHF, right ventricular dysfunction, pericardial diseases, cardiomyopathy, intracardiac shunts, congenital abnormalities

Routine for all studies; may be excluded with high-risk patients, left main coronary or aortic stenosis, severe CHF, renal failure

Not routine unless used as coronary bypass conduit

 

Routine for all coronary angiography

Routine for aortic insufficiency, aortic dissection, aortic aneurysm, with or without aortic stenosis, routine to locate bypass grafts not visualized by selective angiography

Arrhythmia evaluation








Available for patients prone to access site bleeding

CHF, congestive heart failure; IV, intravenous; NTG, nitroglycerin; PTCA, percutaneous transluminal coronary angioplasty.


See Table 1-2 for indications.


image

Figure 1-1 Vascular access routes for cardiac catheterization (also see Chapter 2). Radial and femoral arteries are the most common approaches.



Indications for Cardiac Catheterization


Cardiac catheterization is used to identify structural cardiac diseases such as atherosclerotic artery disease, abnormalities of heart muscle (infarction or cardiomyopathy), and valvular or congenital heart abnormalities. In adults the procedure is used most commonly to diagnose coronary artery disease. Other indications depend on the history, physical examination, electrocardiogram (ECG), cardiac stress test, echocardiographic results, and chest radiograph. Indications for cardiac catheterization are summarized in Table 1-2.


Table 1-2 Indications for Cardiac Catheterization































































Indications Procedures

 

LV, COR

LV, COR

LV, COR

LV, COR, ±ERGO

LV, COR, ±ERGO

LV, COR, ±ERGO

 

LV, COR

LV, COR, ±RH

LV, COR, RH

LV, COR, L+R

LV, COR, R + L

LV, COR, R + L, ±AO

LV, COR, R + L, ±AO

AO, COR

LV, COR, R + L

LV, COR, R + L, ±BX

LV, COR, R + L, BX

AO, aortography; BX, endomyocardial biopsy; COR, coronary angiography; ERGO, ergonovine malate,; LV, left ventriculography; RH, right heart oxygen saturations and hemodynamics (e.g., placement of Swan-Ganz catheter); R + L, right and left heart hemodynamics; ±, optional.






Complications and Risks


For diagnostic catheterization, analysis of the complications in more than 200,000 patients indicated the incidence of risks as death, less than 0.2%; myocardial infarction, less than 0.05%; stroke, less than 0.07%; serious ventricular arrhythmia, less than 0.5%; and major vascular complications (thrombosis, bleeding requiring transfusion, or pseudoaneurysm), less than 1% (Table 1-4, Table 1-5). Vascular complications occurred more often when the brachial approach was used and least when the radial approach was used. Risks are increased in well-described subgroups (Table 1-6).


Table 1-4 Complications of Cardiac Catheterization







































Major
Cerebrovascular accident
Death
Myocardial infarction
Ventricular tachycardia, fibrillation, or serious arrhythmia
Other
Aortic dissection
Cardiac perforation, tamponade
Congestive heart failure
Contrast reaction (anaphylaxis, nephrotoxicity)
Heart block, asystole
Hemorrhage (local, retroperitoneal, pelvic)
Infection
Protamine reaction
Supraventricular tachyarrhythmia, atrial fibrillation
Thrombosis, embolus, air embolus
Vascular injury, pseudoaneurysm
Vasovagal reaction

Table 1-5 Incidence of Major Complications of Diagnostic Catheterizations















































  Number Percent
Death 65 0.11
Myocardial infarction 30 0.05
Neurologic 41 0.07
Arrhythmia 229 0.38
Vascular 256 0.43
Contrast 223 0.37
Hemodynamic 158 0.26
Perforation 16 0.03
Other 166 0.28
Total (patients) 1184 1.98

Modified from Noto TJ, Johnson LW, Krone R, et al: Cardiac catheterization 1990: a report of the Registry of the Society for Cardiac Angiography and Interventions (SCA&I), Cath Cardiovasc Diagn 24:75-83, 1991; in Uretzky BF, Weinert HH: Cardiac catheterization: concepts, techniques, and applications, Walden, Mass, 1997, Blackwell Science.


Table 1-6 Conditions of Patients at Higher Risk for Complications of Catheterization































Acute myocardial infarction
Advanced age (>75 years)
Aortic aneurysm
Aortic stenosis
Congestive heart failure
Diabetes
Extensive three-vessel coronary artery disease
Left ventricular dysfunction (left ventricular ejection fraction <35%)
Obesity
Prior cerebrovascular accident
Renal insufficiency
Suspected or known left main coronary stenosis
Uncontrolled hypertension
Unstable angina

See also Chapter 8.



Catheterization Laboratory Data


Information gathered during the cardiac catheterization can be divided into two categories: hemodynamic (see Chapter 3) and angiographic (see Chapter 4). The term cineangiography describes the x-ray photography of cardiac structures. Use of this term persists even though the images are now stored electronically on digital computer imaging media (e.g., CD-ROM) rather than on cine film. The digital cineangiogram provides anatomic information about the chambers of the heart and the coronary arteries. Hemodynamic information is recorded from catheters inside the heart and consists of pressure measurements, cardiac outputs, and blood oxygen saturation measurements.



Preparation of the Patient



Consent for the Procedure


Consent is obtained by the operator or his or her assistant, usually a physician:






There is no alternative to coronary angiography. Often the patient’s and family’s concern about “not knowing” about coronary disease necessitates performing the test.


The decision to undergo the procedure is always the patient’s. If the patient is reluctant to have the catheterization, the referring physician should be asked to speak to the patient to clarify why the procedure is necessary. A reluctant patient should never sign the consent. When possible, the family should be present when the procedure is discussed. This approach encourages a cooperative and generally sympathetic appreciation of the procedure and expected outcome.




Laboratory Atmosphere: The Patient’s Confidence Builder














In-Laboratory Preparations and the “Time-Out”


The staff of the cardiac catheterization laboratory is responsible for patient preparation before the start of the procedure. On the patient’s arrival in the laboratory, a staff member should review a brief checklist to ensure that all preprocedural requirements have been met. A sample checklist follows:



After all precatheterization requirements have been fulfilled, the patient may be taken to the angiographic suite and the technical preparations can be completed.



Catheterization Suite Preparations


Before the start of the catheterization procedure, the staff performs the following tasks:




Caution must be exercised when premedicating elderly patients. If meperidine (Demerol), fentanyl, or morphine is used, a narcotic antagonist such as naloxone (Narcan) should be available. Flumazenil (a benzodiazepine antagonist) should also be available if diazepam (Valium) or midazolam (Versed) is used.



The “Time Out”


In any active catheterization laboratory, preparations can be hectic, perhaps even frantic at times. This frenetic pace can cause problems, important steps can be missed, and patient safety can be compromised. Time out is a Joint Commission requirement. It was originally designed for surgical procedures that required an accurate identification of the patient, procedure, site, and side. It is a critical safety check to eliminate the mistake of operating on the wrong patient or wrong site.





The Reverse Time Out or “I Need 2 Minutes”


The “time out” before the procedure is a routine safety requirement. However, another kind of “time out” is sometimes needed when the case goes too fast. This is especially true with overeager fellows and catheterization laboratory attendings who sometimes want to work so fast they outstrip the ability of the catheterization laboratory team to keep up with their demands or become confused by conflicting or changing orders from the operators. Whenever this happened, anyone working in the laboratory can call a “time out” (stated outloud as “I need 2 minutes”), which would give them a couple of minutes of uninterrupted time for him or her to get everything caught up and correct. For example, when the circulating nurse is asked, “Please give me NTG, a JR4 6F, set the injector at 12 for 36, and show me the ECG …,” it is clear that this is too much to do quickly enough for the operators, so the nurse called for a time out. The called time out is the request back to the operators to give the nurse, tech, or team 2 minutes to get all the steps, equipment, or setup going and correctly brought together. During complex procedures, the nurse can say, “I need 2 minutes to do xyz …”. Everyone will hear and should understand. The operators will relax and wait for the team to catch up. Of course the called time out would not be appropriate if there was a critical situation occurring in which the patient did not have 2 minutes to wait for an emergency drug or intraaortic balloon pump (IABP)



Sterile Preparations


Cardiac catheterization is performed using aseptic technique in an operating room setting with personnel in scrubs, protective hats, masks, and gowns.




Sterile Field Preparation and Patient Draping


A staff member assigned to assist the physician in the procedure puts on hair and shoe covers and surgical face mask and washes the hands and forearms as a surgical scrub. He or she then puts on a sterile surgical gown and gloves. An equipment stand is prepared in a sterile fashion to hold all the catheters and other equipment to be used during the procedure. At this time, a circulating staff member hands catheters and necessary equipment not included in the sterile catheter laboratory pack to the scrub nurse or technician. A sterile drape is placed over the patient, starting at the patient’s upper chest and extending to the foot, covering the entire examination table.


It is important for all personnel to understand sterile techniques to avoid accidentally contaminating any sterile fields. As a basic rule, no unsterile object may be passed over a sterile field. A sterile gown and gloves rather than gloves alone should be worn when preparing the back table and patient, especially for team members who are very short or wide and whose body may accidentally contact the sterile areas. When moving around a crowded angiographic room, all personnel should be careful to avoid bumping into or passing hands or arms over the sterile tray, table, or patient drapes. Personnel should not walk between the sterile table or equipment tray and the patient. Touching the ends of any catheters, extension tubes, or syringe tips in a sterile field or the power injector syringe tip that is exposed should be avoided.







American Society of Anesthesiologists Physical Status Classification


The American Society of Anesthesiologists Physical Status Classification (Table 1-7) is helpful in determining the patient’s eligibility for conscious sedation. It uses a 1 to 5 classification range, with 1 being a healthy patient and 5 being a moribund patient. Procedural sedation is appropriate for patients in Classes 1, 2, and 3. Patients in classes 4 and higher are better suited for general anesthesia. There are several contraindications to conscious sedation (CS) that include the following:






Table 1-7 American Society of Anesthesiologists Physical Status Classification





















Class Description
1 A healthy patient (e.g., varicose veins in an otherwise healthy patient)
2 A patient with mild systemic disease that in no way interferes with normal activity (e.g., controlled hypertension, controlled diabetes, chronic bronchitis)
3 A patient with severe systemic disease that is not incapacitating (e.g., insulin-dependent diabetes, angina, pulmonary insufficiency)
4 A patient with severe systemic disease that is a constant threat to life (e.g., cardiac failure, major organ insufficiency)
5 A moribund patient who is not expected to survive for 24 hours with or without surgery (e.g., intracranial hemorrhage in coma)

Jun 5, 2016 | Posted by in CARDIAC SURGERY | Comments Off on Introduction to the Catheterization Laboratory

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