- cardiac catheterization
- Cardiac catheter forms
If a patient is diagnosed with heart problems, it is often followed by cardiac catheterization. The heart and the coronary arteries are usually visualized by means of contrast media and X-ray procedures, if necessary, therapy is followed directly. This procedure is used in Germany about 700,000 times a year.
What is a cardiac catheter exam?
In a cardiac catheter examination, a thin plastic tube (catheter) is inserted into the vasculature via a vein (right-heart catheter, "small cardiac catheter") or an artery (left-heart catheter, "large cardiac catheter"). With the help of a contrast agent injected into the catheter, the heart and vessels are visualized in the X-ray image. In most cases, left ventricular catheterization is not only performed for diagnostic purposes, but is also coupled with a therapeutic procedure during the same session.
The cardiac catheter examination certainly involves risks - in addition to bleeding or bruising at the injection site, in particular cardiac arrhythmias, heart attacks, strokes or vascular injuries. The contrast agent used in coronary angiography may lead to allergic reactions and (transient) impairment of renal function. Particularly at risk are older people or those with chronic diseases such as kidney or heart failure. Therefore, the risks must always be balanced with the hoped-for benefits.
The left heart catheter
The more frequent left ventricular catheterization will diagnose abnormal changes in the coronary arteries, heart valves, myocardium or heart defects of the left atrial or left ventricular valves. Knowing the exact location of constrictions on the coronary arteries is necessary, for example, to perform a vessel dilation with the aid of a balloon (balloon dilatation) or a bypass operation.
For examination, after local anesthesia, the catheter is advanced against the direction of flow to the left ventricle via a puncture site in the groin (or more rarely over an exposed artery in the elbow). Then an X-ray contrast agent is injected into the left ventricle, the main artery and the left and right coronary arteries. On the monitor, the doctor can then determine exactly where the vessels are narrowed or closed.
This part of the left heart catheter examination is called coronary angiography and can be supplemented by an ultrasound examination (IVUS = intravascular ultrasound) and a pressure measurement in the blood vessels (pressure wire).
The right heart catheter
With the right heart catheter v. a. the pressure in the pulmonary arteries and the pumping power of the heart are measured. Therefore, one usually comes without contrast medium and X-ray. The right-heart catheter is usually inserted via a puncture site on the crook of the arm, occasionally over the groin. At the tip of the tube is a tiny inflatable balloon, which is inserted into the vein with the catheter and then inflated. The balloon is flushed with the bloodstream into the right atrium and through the right ventricle into the pulmonary artery (therefore also "Einschwemmkatheter").
During the examination, the catheter stops for a short time at the different heart sections in order to measure the blood pressure and the oxygen saturation of the blood at these points. Increased pressure in the pulmonary circulation can be a sign of a circulatory disorder of the heart muscle.
Stress test as additional examination
Often, the right heart catheter is associated with a stress test. In doing so, the patient enters a bicycle pedal while lying down. The values measured with this physical load are then compared with the corresponding resting values and thus provide information about the heart function as a whole. This value difference is particularly important in assessing the effectiveness of heart valves.
Increased pressures in the pulmonary circulation during exercise can also be a measure of the size and effectiveness of heart septal defects. In case of suspected changes in the right half of the heart, however, a contrast agent-controlled X-ray examination can of course also be performed via the right heart catheter.
Cardiac catheter as a therapy instrument
As part of a cardiac catheterization usually directly therapeutic measures such as the expansion of the coronary arteries (PTCA) using an expansion balloon or in addition the stabilization of the vessel wall by means of a support grid (stent) is performed. Cardiac muscle biopsies are also possible. In this case, there is a pliers instrument on the catheter, with which a tissue sample can be taken.