What to Expect When Getting an Angiogram Through the Groin
Note: this post will apply to angiograms from the groin (femoral) approach. For other approaches look to other posts.
Introduction
Anytime a patient receives an angiogram the first step of the procedure is "getting access."
What this means is the physician needs to get into the vascular system. This post will give an overview of a femoral approach to an angiogram. In other words, what to expect when a physician accesses your arterial system for an intravascular (inside a blood vessel) procedure.
Definitions
Before we dive into how groin arterial access works, we should review a little anatomy. An artery is a blood vessel that conducts blood away from the heart to the body. This can be going to an organ or the periphery, such as the toes.
Arteries are high pressure and are the subject of this post. A vein is low pressure and conducts blood back to the heart. The vascular system is much like the pipes of a house in that they are all interconnected. Imagine there was no water in the system and that you were small enough to fit in the pipes, you could walk through your water pipes from one room to another. You could even walk via the water main into your neighbor's house.
The femoral artery is the large artery in the groin. If you lie flat and push firmly with your fingertips, you'll feel the pulsations (remember arteries are high pressure!) through your fingertips. The bouncing is a result of your heart pumping blood into elastic vessels. The femoral artery is relatively large and has historically been the vessel of choice.
The femoral artery crosses over the pelvis at the level of the hip joint, giving a hard backstop to compress the vessel. This makes it both easier to feel and safer when the devices are removed. The common femoral is the continuation of the external iliac artery and extends until it splits into two vessels, the superficial femoral artery and the profunda (deep) femoral artery.
As implied above there are other options, but the common femoral artery is the most commonly used. It is large enough to accommodate bigger intravascular (inside the blood vessel) devices and that it's compressible, meaning when the devices come out the physician can control the hole in the artery and allow it to heal without large blood losses.
Procedure Day
When you arrive for your procedure you will get an IV and labs will be drawn if required. You'll be placed in a hospital gown for procedural cleanliness and to prevent your clothing from becoming soiled.
You will be asked to lie on a procedure table. If your procedure is scheduled with general anesthesia you will go to sleep. If not, you will be asked to lie still while your groin is shaved and cleaned. A special blue drape that is completely sterile will be used to cover the area with a small hole for working. Everything on the drape is completely sterile. So it's important that you do not reach above or through the drape.
Typical interventional suite or "cath lab."
An X-ray device will be brought over you. This is so that the operator can evaluate your anatomy and ensure that he/she accesses the artery in a safe location. Medications to help you relax are then administered.
Once the groin is suitably prepped, either manual pressure or ultrasound will be used to specifically identify the vessel location. The area will then be anesthetized (numbed) with medication. The medication burns and it takes 10 seconds or so to start working. This is typically the most painful part of the procedure. It is important you hold still the pain will pass!
Once the area is anesthetized, a small 1/4" incision is made and the tissue below the skin is gently dissected to clear a path to the artery. The artery is then accessed with a very thin needle. As the artery is high pressure, blood spontaneously bleeds back through the needle confirming the artery has been successfully accessed. Through the needle, a small metal wire is advanced. Wires are used to maintain the position of an accessed vessel to exchange a catheter (tube in the blood vessel) for a different catheter or device.
A sheath will then be placed. A sheath is a tube with a diaphragm on the external end that allows tools to be introduced into the blood vessel without the high-pressure blood bleeding back. Sheaths are generally connected to fluids to keep blood from becoming stagnant in the sheath and clotting off. Occasionally, some blood will leak around the device or can backbleed when devices are exchanged. This will feel like warm liquid in your groin and may drip into your vagina or rectal area. This is normal. The amount of blood is generally very little.
Once the sheath is in it's time for the procedure, whatever that may entail. At this point, it's not uncommon for the patient to have no further pain. Blood vessels have no nerves in the lining. If you do feel pain, it’s important to let the operator know. This is not necessarily abnormal and could be anticipated and a normal part of the procedure.
At the conclusion of the procedure, the devices are removed and the hole in the artery closed. A topic for a future blog post!