A right heart catheterization (RHC) is an invasive diagnostic procedure that allows physicians to gather information directly from inside the heart and the major blood vessels leading to the lungs. This technique involves temporarily inserting a long, thin tube, called a catheter, through a vein to reach the right side of the heart. The RHC’s primary purpose is to obtain precise measurements of blood pressure and oxygen levels within the heart chambers and pulmonary circulation. This direct hemodynamic data offers an accurate physiological assessment of how well the heart and lungs function together.
How the Procedure Diagnoses Heart and Lung Conditions
The catheter is used to directly measure pressures in the right atrium, the right ventricle, and the pulmonary artery. A particularly important measurement is the pulmonary capillary wedge pressure (PCWP), which provides an indirect estimate of the pressure in the left atrium. These detailed hemodynamic data are used for diagnosing several complex cardiopulmonary conditions.
These precise pressure readings are combined with a calculation of the cardiac output, which is the volume of blood the heart pumps per minute. Cardiac output is often measured using the thermodilution method or the Fick method. Calculating the cardiac output alongside the pressure measurements allows physicians to determine the resistance to blood flow in the lungs, known as pulmonary vascular resistance.
This collection of data helps accurately diagnose and classify conditions like pulmonary hypertension, which is defined by an elevated mean pulmonary artery pressure (typically above 20 mmHg). The measurements also help differentiate between various types of heart failure, such as distinguishing whether the problem lies primarily in the heart’s pumping ability or its filling capacity. RHC is also used to assess the severity of shock and to guide therapies for patients awaiting heart or lung transplantation.
Navigating the Right Heart: The Procedure Steps
The right heart catheterization procedure is performed in a cardiac catheterization laboratory under sterile conditions and usually takes less than an hour. The patient is positioned on a table and connected to monitors that track the heart’s electrical activity, heart rate, and blood pressure throughout the test. A mild sedative may be given to help the patient relax, but they will remain conscious and able to follow instructions.
The access site, most commonly a vein in the groin (femoral vein) or the neck (internal jugular vein), is thoroughly cleaned and numbed with a local anesthetic. Once the area is anesthetized, a small puncture is made to insert a short, hollow tube called an introducer sheath into the vein. This sheath acts as a channel through which the pulmonary artery catheter, often a Swan-Ganz catheter, is passed.
The catheter is then gently guided through the large veins of the body, traveling through the vena cava and into the right atrium of the heart. To facilitate its movement, a small balloon near the catheter tip is typically inflated once it is inside the right atrium. This allows the catheter to “float” with the flow of blood through the tricuspid valve into the right ventricle.
From the right ventricle, the catheter is advanced through the pulmonary valve and into the main pulmonary artery. The physician uses fluoroscopy, a form of continuous X-ray imaging, to visualize the catheter’s movement on a screen in real time, ensuring correct placement. Pressures are recorded precisely at each stage of the catheter’s journey, from the right atrium to the final “wedge” position in a small branch of the pulmonary artery.
Patient Preparation and Recovery Expectations
Preparing for an RHC typically involves several steps to ensure the procedure is safe and yields accurate results. Patients are usually instructed not to eat or drink for several hours before the test (NPO status), often for six hours or more. This fasting period is necessary in case sedation is administered during the procedure.
Patients taking blood thinners are often told to temporarily stop the medication or adjust the dose a few days prior to minimize the risk of bleeding at the insertion site. Blood tests are often required beforehand to check kidney function and assess the blood’s clotting ability. It is helpful to wear loose, comfortable clothing to the hospital and to arrange for a responsible adult to drive home after the procedure, especially if any sedation was administered.
After the catheter is removed, immediate recovery focuses on controlling bleeding at the puncture site. A member of the medical team applies firm pressure to the site for several minutes, or a special closure device may be used. If the catheter was inserted in the groin, the patient must lie flat for a few hours, sometimes up to six, to allow the vein to seal securely.
Upon returning home, activity restrictions are important for the first 24 to 48 hours to prevent complications. Patients should avoid strenuous activity, including heavy lifting or pushing heavy objects. The insertion site must be kept clean and dry; patients should avoid soaking the wound in a bath, hot tub, or pool for about a week, though showering is permitted after 24 hours.
Understanding Potential Complications
Right heart catheterization is considered a relatively safe procedure when performed by experienced medical professionals. The most common minor risks involve the access site, such as mild bruising, tenderness, or a small amount of bleeding or oozing. These symptoms usually resolve quickly and can be managed with simple care instructions at home.
More serious complications can occur, including heart rhythm disturbances (arrhythmias), which are monitored and managed during the procedure. If the subclavian vein is used, there is a risk of a pneumothorax (collapsed lung) due to the proximity to the chest cavity. There is also a risk of the catheter causing damage to the heart or pulmonary artery, though fluoroscopy guidance minimizes this.
Patients should immediately contact their healthcare provider if they experience any of the following warning signs after returning home:
- Signs of infection, such as fever, chills, or excessive redness, swelling, or drainage from the insertion site.
- Severe pain or prolonged bleeding that does not stop with pressure.
- New symptoms like shortness of breath.
- Numbness or tingling in the limb where the catheter was inserted.