Right Heart Catheterization for Pulmonary Hypertension (PH)
Roham Zamanian, MD
Associate Professor of Pulmonary Medicine Director, Adult PH Program, Stanford School of Medicine
Right heart catheterization (RHC) is a diagnostic procedure used to measure pulmonary artery pressures and thus evaluate whether a patient has pulmonary hypertension or not, and sometimes what is causing the pulmonary hypertension. RHC is typically an outpatient same-day procedure (performed in the cardiac catheterization laboratory) which does not require hospitalization – meaning patients come to the hospital, have the procedure done, and go home after a brief recovery period.
One of the most important facts about right heart catheterization is that it is the gold standard for diagnosing PH. It is important for patients to understand that without a RHC, physicians cannot and typically should not prescribe PH-specific therapies.
Procedure in detail:
After an appointment is set for right heart catheterization, patients will receive instructions on how to prepare for the procedure. Patients usually need to be “NPO” (meaning fast so that they an empty stomach) for approximately 6 hours prior to the procedure. Your physician will instruct you on what to do with your usual medications during this period, especially blood thinners. Once patients arrive to the procedure area, they will have some blood work done and then consented for the procedure. The consenting process is one which the physician or his/her assistant will describe the risks and benefits of the procedure and obtain permission for the procedure.
Right heart catheterization is safe when done at centers with expertise in pulmonary hypertension. The exact risk and benefits of the procedure are based on each individual’s medical condition, but often the benefits outweigh the risks of the procedure. Once consent is obtained, patients are brought into a catheterization room and draped and prepped so that the procedure can be done in a sterile manner. The expert physician will then place an intravenous line in either the neck or groin vein and then insert a long catheter which will be used to make measurements [photo of or demonstrate a swan-ganz catheter]. This cardiac catheter will have a balloon at the tip which will be inflated by the physician allowing for the catheter to “float” thru the right heart and into the lungs.
At specific locations in the body, the physician will make pressure measurements and obtain blood samples. These measurements will allow for the physician to compare to normal numbers and decide whether a patient has pulmonary hypertension and sometimes decide on what is causing it. Blood oxygen measurements at different places in the heart and the lungs can also allow physicians to diagnose congenital heart diseases.
After making baseline measurements, sometimes physicians need to perform different diagnostic maneuvers (known as provocative testing) during the right heart catheterization. There are a variety of provocative testing options. Most commonly patients will receive an inhaled or intravenous medication to test how much the pulmonary arteries can relax in response to blood vessel dilators. This is called a vasoreactivity challenge and it’s the most common type of provocative testing. Other tests include exercise challenge (to see if patients develop PH with exercise) and fluid challenge (to see if blood volume worsens pressures and left heart function). Finally, if a physician is concerned about blood clots or abnormal vascular connections, a pulmonary angiogram (AKA pulmonary angiography) is performed. By injecting contrast into the vessels, the physician can take a movie of the contrast flowing thru the pulmonary arteries and decide if are any abnormalities.
In some patients, because the physician maybe worried about left heart function or coronary artery disease, a left heart catheterization will be performed at the same time. Left heart catheterization is similar to the procedure of right heart catheterization with the major exception that the IV is placed in an artery instead of a vein and a catheter is sent into the aorta and eventually the left heart.
Most right heart catheterizations take about 30-45 minutes to complete, but a little bit longer if a left heart catheterization or pulmonary angiography needs to be performed.
Recovery and follow up:
After a complete cardiac catheterization (right plus or minus left), the physician will provide initial findings to the patient and family. At Stanford, we mandate that all patients come back within 1-2 weeks of the procedure to hear the complete results and make therapeutic decisions. The immediate recovery from a RHC is about 3-4 hours. Because patients receive conscious sedation (light/low dose medications for pain and anxiety), we do not permit driving for 24 hours. Care of the site of surgery is specific to each individual patient and care plans are provided at time of check out. We encourage our patients to contact the on-call doctor if there are any concerns or complications which arise after discharge. At Stanford, our patients receive a follow up phone call from a nurse the day after their procedure.
As mentioned in the introduction, a baseline RHC is mandatory for the diagnosis of PH and specifically PAH. However there is variability in practice of performing follow up right heart catheterization. At Stanford, we believe data from RHC is very important and we usually recommend re-evaluation every 18-24 months except if there is concern for progression of disease in which case we recommend immediate follow up right heart catheterization.