Interventional cardiologists perform minimally invasive, catheter-based procedures to diagnose and treat heart disease without open-heart surgery. Their work ranges from opening blocked arteries with stents to replacing heart valves, closing holes in the heart, and removing blood clots during active heart attacks. Most of these procedures involve threading thin, flexible tubes called catheters through a blood vessel in the wrist or groin and guiding them to the heart.
Diagnostic Cardiac Catheterization
Before treating anything, interventional cardiologists need to see what’s happening inside the arteries. Diagnostic catheterization is the foundational procedure. A catheter is guided into the coronary arteries, and contrast dye is injected so the arteries show up clearly on X-ray. This produces a real-time map of blood flow, revealing where blockages or narrowings exist and how severe they are.
When a blockage looks moderate on imaging and the cardiologist isn’t sure whether it’s actually restricting blood flow, they can measure it directly using a technique called fractional flow reserve (FFR). A specialized pressure-sensing wire is threaded past the blockage, and the pressure on each side is compared. If the pressure drops significantly across the narrowed segment, the blockage is limiting blood flow and likely needs treatment. If the ratio stays close to normal, the blockage can often be left alone and managed with medication. This measurement prevents unnecessary stenting and helps cardiologists focus treatment where it will make the biggest difference.
Interventional cardiologists also use miniature imaging tools placed directly inside the arteries. Intravascular ultrasound sends sound waves outward from inside the vessel to create a cross-sectional picture of the artery wall, showing how much plaque has built up and helping select the right stent size. Optical coherence tomography uses light instead of sound and produces even more detailed images, though it can’t see as deeply into the vessel wall. These tools are especially useful for planning complex procedures and confirming that a stent has been properly expanded after placement.
Angioplasty and Stent Placement
Percutaneous coronary intervention, commonly called angioplasty with stenting, is the most recognized procedure interventional cardiologists perform. It treats narrowed or blocked coronary arteries by physically reopening them from the inside.
The process starts with a guidewire threaded through the catheter and across the blockage. A tiny balloon, mounted on a separate wire, is slid over the guidewire and positioned directly at the narrowed segment. The balloon is inflated and deflated repeatedly until the artery opens up. In most cases, a stent is then needed to keep the artery open. The balloon is removed and exchanged for a stent, which is a small latticed metal tube crimped over another balloon. Once positioned at the blockage site, the balloon expands the stent against the artery wall. The balloon deflates and is pulled out, but the stent stays permanently in place. It cannot be removed once expanded.
Modern stents are coated with medication that slowly releases over months, reducing the chance that scar tissue will regrow inside the stent and re-narrow the artery.
Treating Heavily Calcified Arteries
Some blockages are so hardened with calcium deposits that a balloon alone can’t push through them. In these cases, interventional cardiologists use specialized tools to break up the calcium before placing a stent.
Rotational atherectomy uses a diamond-tipped burr that spins at extremely high speeds on a thin driveshaft, grinding through calcified plaque as it moves along a guidewire. Orbital atherectomy works on a similar principle but uses a spinning crown that orbits within the artery, sanding down hard deposits. A newer approach, intravascular lithotripsy, takes a different tactic entirely: it delivers sonic pressure waves from inside the artery to crack calcium deposits without grinding, similar in concept to how kidney stones are broken up. Each of these techniques prepares the artery so that a balloon and stent can be deployed effectively.
Emergency Clot Removal During Heart Attacks
When someone arrives at the hospital with an active heart attack, an interventional cardiologist’s job is to restore blood flow as quickly as possible. The blocked artery is usually clogged by a blood clot that formed on top of a ruptured plaque.
In some cases, the cardiologist will use aspiration thrombectomy, threading a special catheter to the clot and applying suction to physically pull it out. Manual aspiration catheters use a syringe to create negative pressure, while newer mechanical systems like the Indigo system provide continuous, more powerful suction through a larger opening. There are also stent-retriever devices, originally developed for stroke treatment, that can snare and extract clots from coronary arteries. After the clot is removed, the cardiologist typically proceeds with balloon angioplasty and stenting to treat the underlying blockage that triggered the heart attack.
Transcatheter Aortic Valve Replacement
Replacing a diseased aortic valve used to require open-heart surgery. Interventional cardiologists (often working alongside cardiac surgeons) now perform transcatheter aortic valve replacement, or TAVR, through a catheter instead. This procedure is used when the aortic valve has become severely narrowed, a condition called aortic stenosis that makes the heart work dangerously hard to pump blood.
The most common approach goes through the femoral artery in the leg, which is the least invasive route. If that artery is too small or diseased, alternative access points include the artery under the collarbone, a direct approach through the chest wall to the aorta, or even through the tip of the heart itself. Two main valve designs exist. One type uses tissue from a cow’s heart lining mounted on a metal frame and is expanded into position with a balloon. The other uses pig tissue on a frame made from a flexible metal alloy that expands on its own once released, with the added advantage that the cardiologist can reposition it before final deployment if the initial placement isn’t quite right.
Mitral Valve Repair
The mitral valve sits between the two left chambers of the heart, and when it doesn’t close properly, blood leaks backward with each heartbeat. Interventional cardiologists can now repair this valve without surgery using a procedure called transcatheter edge-to-edge repair.
A small clip device is delivered through a catheter inserted in a leg vein, guided up into the heart, and used to pinch together portions of the two mitral valve leaflets. This mimics a surgical stitch technique and reduces the amount of backward leakage. The procedure received FDA approval for one type of mitral leak in 2014 and a second type in 2018, and it remains the most widely used catheter-based option for mitral valve repair.
Closing Holes in the Heart
Some people are born with a small opening between the upper chambers of the heart. A patent foramen ovale (PFO) is a flap-like opening that was normal in fetal development but didn’t seal after birth. An atrial septal defect (ASD) is a more defined hole in the wall between the chambers. Both can allow blood clots to cross from the right side of the heart to the left and travel to the brain, potentially causing a stroke.
To close these defects, an interventional cardiologist threads a catheter through a leg vein into the heart and positions a closure device at the hole. The device is a small, umbrella-like structure with two discs. As it’s pushed out of the catheter, each disc opens on one side of the hole, sandwiching the tissue between them. The cardiologist confirms proper placement using X-ray and ultrasound imaging before releasing the device. Over time, heart tissue grows over it, permanently sealing the opening.
When PCI Isn’t the Right Choice
Not every blocked artery is best treated with a catheter-based procedure. The 2025 guidelines from the American College of Cardiology and American Heart Association recommend that a heart team, including both interventional cardiologists and cardiac surgeons, evaluate patients with complex disease to determine the best approach. Coronary artery bypass surgery tends to produce better long-term outcomes in specific situations: patients with diabetes who have blockages involving the main artery on the front of the heart, people with complex disease in the left main coronary artery, and those with severe blockages spread across multiple vessels. The decision between catheter-based treatment and surgery depends on how complex and widespread the artery disease is, the patient’s other health conditions, surgical risk, and the feasibility of each approach.
Recovery After Catheter-Based Procedures
One of the biggest advantages of interventional cardiology is the recovery time. Most people who undergo angioplasty and stenting can walk within six hours, and full recovery takes about a week. When the catheter is inserted through the wrist, recovery tends to be even faster than groin access.
If the catheter went through the groin, you’ll need to limit stair climbing to about twice a day for the first two to three days and avoid driving, yard work, lifting heavy objects, or sports for at least two days. For wrist access, the main restriction is avoiding lifting anything heavier than about 10 pounds (roughly a gallon of milk) and skipping heavy pushing or pulling. Regardless of access site, you should keep the insertion area dry for one to two days, avoid baths and swimming for the first week, and expect to return to work within two to three days if your job doesn’t involve physical labor.
For patients with reduced kidney function, the contrast dye used during these procedures poses a risk of kidney stress. Hydration before and after the procedure is the primary protective strategy, with intravenous fluids typically started several hours beforehand and continued for six to twelve hours afterward.