Diagnosing pulmonary hypertension via a right heart catheterization
Although several tests such as an echocardiogram may suggest a diagnosis of pulmonary hypertension, a right heart catheterization (RHC) is the only way of accurately measuring the pulmonary artery pressures and officially diagnosing pulmonary arterial hypertension. RHCs are also often done after diagnosis as a way to monitor pulmonary hypertension patients and help direct treatment for the disease.
What is a right heart catheterization?
The right heart catheterization is usually performed as an outpatient procedure by a cardiologist or pulmonologist in the cath lab of a hospital. Make sure to check with your physician regarding any preparation required for the procedure. Certain medications should not be taken prior to a RHC and the patient is usually NPO (nothing to eat or drink) for several hours prior to the procedure. Every procedure has risks and benefits and it is important that your physician explains these and you fully understand them. You should have an opportunity to ask any questions about the procedure prior to arriving at the hospital.
The day of the procedure the patient will arrive at the pre-catheterization area in the hospital and change into a hospital gown. Like any procedure it is important to bring a complete list of your medications and list the last time that you took each medication. A nurse will prep the patient. Prep includes starting an IV, drawing labs, reviewing medications and allergies, and confirming that the appropriate pre-procedure preparation was performed such as holding certain medications. The patient is then transported to the cath lab.
The physician and other health care professionals performing the heart cath will be wearing sterile gloves, masks, and gowns. They will have caps on covering their hair. The patient is awake during the procedure but medications are used to help keep them calm and comfortable. The procedure is not painful but can be uncomfortable for some patients. A thin catheter is inserted into a vein in the groin or in the neck after the skin above the area is cleaned and numbed with medication. Then the catheter is advanced into the heart. The catheter is equipped to take pressure measurements in the chambers of the right heart as will as the pulmonary arteries. The physician is also able to measure how much oxygen is in your blood and your cardiac output (the amount of blood your heart pumps).
The procedure usually takes less than an hour. At the end of the procedure the catheter is removed. Nothing is permanently left in the body following a routine right heart catheterization. If the test demonstrates severe pulmonary hypertension the patient may be admitted to the hospital to initiate treatment. Otherwise the patient is taken back to the prep area to wait for any sedatives used to wear off. It is suggested that someone else drive the patient home. Upon discharge the patient should take it easy for the rest of the day and check with their physician to see when they can return to normal activity. They should make an appointment with the physician that ordered the right heart catheterization to go over the results in the upcoming weeks.
What measurements from the right heart catheterization diagnose pulmonary hypertension?
The hemodynamic definition of pulmonary arterial hypertension (PAH) is a mean pulmonary artery pressure at rest greater than or equal to 25 mmHg in the presence of a pulmonary capillary wedge pressure less than or equal to 15 mmHg. These measurements can only be taken accurately during a right heart catheterization. Other measurements such as the right atrial pressure (the pressure in the right atrium of the heart), pulmonary vascular resistance or PVR (the resistance the right ventricle must overcome to pump blood into the pulmonary arteries, and cardiac output (the amount of blood your heart pumps) are also very useful to determine how severe the pulmonary hypertension is and will help direct treatment for pulmonary hypertension.