Cardiac catheterization is a common procedure that allows doctors to examine the heart. A thin tube is inserted into a blood vessel in the leg or arm, and then it is advanced through the body until it reaches the heart. A catheter can be used to measure pressure in the heart, to inject a contrast agent before an x-ray, to take a blood test, a biopsy, and to check the condition of the chambers and heart valves. Since catheter insertion is an invasive intervention, it is important to minimize the risk of infection before and after the procedure.
Varieties of Cardiac Catheterization
There are two types of this procedure:
- large catheterization (or catheterization of the left heart) is performed more often, the catheter is advanced through the aorta into the left ventricle to the coronary vessels,
- small catheterization (or catheterization of the right heart) - a catheter in the right heart and pulmonary arteries can be inserted through the veins of the inguinal region or elbow, sometimes floating catheters that enter the heart along with venous blood flow are used.
In addition, synchronous (or simultaneous) catheterization can be performed, during which two catheters are inserted into the heart through an artery and vein. During the procedure, they can be placed opposite each other so that they are separated only by a heart valve (for example, aortic or mitral). This technique allows you to calculate the pressure gradient created by the openings of the heart valves.
Cardiac catheterization for diagnostic purposes is prescribed in cases where the doctor needs to get the most detailed information about the patient’s coronary vessels and heart, and other examination methods cannot provide comprehensive data on the degree, causes of hemodynamic disturbances and its features. After receiving the results, the specialist can draw up the correct treatment plan (for example, prescribe a surgical operation).
Diagnostic cardiac catheterization can be prescribed in the following clinical cases:
The procedure allows you to establish the nature of the lesions of the coronary vessels, myocardial tissue or heart valves, which cannot be determined by other studies (i.e. if they show doubtful results). In addition, cardiac catheterization makes it possible to assess the severity of such injuries and to study the pathophysiological mechanisms of changes in myocardial function. As a rule, such a diagnostic method is prescribed before performing cardiac surgery.
Cardiac catheterization for therapeutic purposes can be prescribed in the following cases:
- treatment of certain heart defects,
- the need for disclosure of narrowed (stenosed) channels,
- intracoronary thrombolysis,
- performing stenting or angioplasty of unhealthy arteries.
Cardiac catheterization can be performed by patients of any age in the absence of contraindications for such a diagnostic method or treatment.
In some cases, cardiac catheterization cannot be performed if there are the following relative contraindications:
- acute infectious diseases
- systemic infection
- unsolved digitalis intoxication or hypokalemia,
- pulmonary edema,
- severe peripheral atherosclerosis,
- uncontrolled hypertension or arrhythmia,
- decompensated heart failure,
- severe anemia
- severe coagulopathy,
- an allergic reaction to the contrast agent used,
- gastrointestinal bleeding,
- severe renal failure,
- pregnancy and lactation.
The need for catheterization in such cases is established for each patient individually and entirely depends on the clinical case. Usually, the procedure can be carried out after eliminating the contraindication or after special preparation of the patient.
Sometimes specialists have to dispense with the appointment of such a diagnostic procedure due to the patient's refusal to perform it.
When prescribing cardiac catheterization, the patient must inform the doctor about such conditions:
- possible pregnancy
- taking medications or dietary supplements,
- taking sugar-lowering drugs,
- the presence of an allergic reaction in the past to iodine, radiopaque agents or seafood, latex or rubber,
- taking Viagra or other drugs to eliminate erectile dysfunction.
Especially careful preparation of the patient for the study is recommended in the following clinical cases:
- the presence of severe concomitant pathologies (insulin-dependent diabetes, severe pulmonary failure, renal failure, severe damage to peripheral or cerebral vessels),
- belonging to the IV functional class of heart failure (NYHA classification),
- severe left ventricular dysfunction,
- patient age up to 1 year or older than 70 years.
In the above cases, cardiac catheterization is performed with extreme caution, since in the presence of these conditions the risk of a possible fatal outcome increases.
After the appointment of the procedure, the doctor will surely acquaint the patient with the principles of the research technique and possible risks and contraindications. After that, the patient signs the documents of consent to the catheterization, and the specialist gives him detailed recommendations on preparation for the upcoming examination:
- 14 days before the procedure, the patient takes blood tests, urine tests, and undergoes an ECG, echocardiography, and chest x-ray. If necessary, the doctor may prescribe additional studies.
- If necessary, a change in the regimen of taking some medications or taking medications (sedatives, anticoagulants, etc.) may be recommended.
- The patient may come to the procedure on the day of the study or be hospitalized 1-2 days before catheterization. When registering in a hospital, the patient should take with him the necessary things (slippers, comfortable clothing, hygiene products, etc.). The same items may be needed if the patient will remain under medical supervision after the procedure. Therefore, they should be taken from home before visiting the diagnostic center.
- If necessary, a test for a local anesthetic used for pain relief or a contrast drug may be performed.
- Do not forget to take on time those medicines that were prescribed by the doctor in preparation for the study.
- In the evening before the test, take a shower and shave the hair from the area of the proposed introduction of the catheter.
- 6-8 hours before the examination, you must refuse to take fluids and food.
- If after the procedure the patient plans to go home, then he must have an accompanying person.
- Before the procedure, leave dentures, a hearing aid, glasses, a telephone and other objects that interfere with the study at your loved ones or in the ward.
The patient should remember that cardiac catheterization is a painless procedure. During the study, he will be conscious, be able to communicate with the doctor and perform those actions that will be recommended to him by a specialist.
Sometimes during the procedure, palpitations, a slight burning sensation at the site of insertion of the catheter, or a feeling of heat may be felt. These somewhat uncomfortable sensations should not scare the patient, because they do not indicate any complications and quickly resolve themselves after the study is completed.
How is catheterization performed?
- An hour before the procedure, a sedative is administered to the patient.
- After transportation to a specially equipped office, he is offered to change into disposable clothes and lay on the table.
- The nurse punctures the patient’s vein to infuse the necessary drugs. If necessary, a catheter is inserted into the bladder.
- The doctor disinfects the injection site of the cardiac catheter (elbow, wrist or inguinal zone) and performs local anesthesia. After achieving an analgesic effect, the specialist makes a small incision to insert a catheter or punctures the vessel with a thick needle.
- The doctor begins to insert a catheter into the selected blood vessel and, under fluoroscopic control, advances it to the ventricles of the heart or coronary vessels.
- After reaching the left or right ventricle, a pressure gauge is attached to the catheter and pressure is measured. If necessary, other necessary procedures are performed (biopsy, aortogram, etc.).
- To perform angiography, a radiopaque agent is introduced into the catheter, making the ventricles and coronary vessels visible. A specialist examines their condition, takes pictures and makes the necessary conclusions. When taking pictures, the doctor may ask the patient to hold his breath, take a deep breath or cough.
- With the introduction of contrast for the study of the ventricles of the patient for several seconds, a sensation of heat or warmth may appear. If the drug is administered only to study the condition of the coronary arteries, then such a sensation does not appear, since a smaller dose of the iodine-containing drug is used for this. If after the introduction of contrast the patient feels itching, nausea, a lump in the throat or tightness in the chest, then he should immediately inform the doctor about them.
- If necessary, dosed exercise or physiological tests may be recommended during the study. For this, a device such as an ergometer is used.
- After completion of the study, the doctor removes the cardiac catheter, if necessary, sutures in place of a small incision or collagen sealant. After this, a pressure bandage is performed to prevent bleeding and the formation of subcutaneous hematomas.
- The nurse removes the needle that is being inserted for intravenous infusion and the catheter from the bladder (if it was inserted).
After completion of cardiac catheterization, the patient can go home after full stabilization of the general condition (usually this happens after a few hours) or remains under medical supervision until the next morning.
What special tests can be performed during cardiac catheterization?
During cardiac catheterization, the following examination methods can be performed:
- angiography - to visualize the chambers of the heart, coronary vessels, pulmonary arteries and aorta,
- study of intracardiac bypass blood - to determine the level of oxygen in different parts of the heart and major vessels,
- intravascular ultrasound - performed using a miniature ultrasound probe attached to the end of a cardiac catheter to study the lumen of the vessel, coronary artery wall and non-linear blood flow,
- endomyocardial biopsy - performed using a special biopsy catheter, performed to identify conditions provoked by infiltrative and infectious diseases, or transplant rejection reactions,
- measurement of cardiac blood flow or output - the technique is carried out using the method of thermal dilution, indicator dilution or the Fick method,
- measurement of blood flow in the coronary arteries - performed using special catheters with Doppler flow sensors or built-in pressure sensors that evaluate the degree of vascular stenosis.
After the procedure
After completion of cardiac catheterization, the patient is recommended:
- A few hours after the study, be under medical supervision. The doctor may recommend that you stay in the hospital until the next morning or allow you to go home on the day of the catheterization, but only after the general condition has been completely stabilized.
- If the catheter was inserted through the inguinal region, then to prevent bleeding after the procedure, lie down for several hours on the back.
- If a catheter was inserted into the ulnar vein, then after the study you can not bend your arm for several hours.
- Take an anesthetic if there is pain at the injection site after the end of local anesthesia.
- After the procedure, you can not drive. Someone must accompany the patient to the house.
- After administering a contrast medium, drink at least 2 liters of water over the next 24 hours (for the most rapid removal of the drug from the body).
- Timely perform processing of the catheter insertion site with an antiseptic solution and change the dressing.
- Start taking a shower only after doctor's permission.
- Limit physical activity during the week.
- If before the procedure, the doctor canceled the intake of any drugs, then it should be clarified with a specialist when it will be possible to continue the course of therapy.
- Re-visit the doctor on the appointed day.
With proper preparation of the patient, identifying all possible contraindications and the high qualification of the doctor performing the study, complications after cardiac catheterization rarely develop. The possible consequences of the procedure largely depend on which parts of the heart are examined.
When performing catheterization of the right ventricle, there is a small risk of developing arrhythmias and pulmonary edema, and most often there are ventricular or atrial arrhythmias. In extremely rare cases, pulmonary infarction, perforation of the right ventricle or pulmonary artery may develop. When conducting a study of the left parts of the heart, accumulation of air or blood in the pleural cavity and damage to the pericardium are possible.
Sometimes during or after cardiac catheterization, some other complications may occur:
- a sharp decrease in blood pressure,
- myocardial infarction
- coronary vessel damage,
- catheter insertion site infection
- catheter bleeding
- an allergic reaction to the contrast agent used,
- kidney damage due to the use of contrast (usually occurs with diabetes mellitus or kidney pathologies),
It should be noted that stroke and myocardial infarction during cardiac catheterization can occur only in 0.1% of cases, and a fatal outcome in 0.1-0.2% of patients. The frequency of stroke increases in patients who are already 80 years old.
Cardiac catheterization is an invasive but highly informative diagnostic procedure. In some clinical cases, it cannot be replaced by other, non-invasive modern examination methods. With proper preparation for the study, observing the recommendations of a specialist, a highly qualified doctor and identifying all possible contraindications, the risk of complications of this procedure remains low. In some cases, cardiac catheterization is performed for therapeutic purposes.