OCT (Optical Coherence Tomography)

No. It is done inside your angiogram or angioplasty, through the same tube already in your wrist or groin, and it adds a few minutes. There is no separate admission, no separate anaesthetic and no extra puncture.

The imaging itself does not. During each pullback there is a short flush of dye that briefly interrupts blood flow down the artery — some patients feel a few seconds of chest heaviness, or a warm flush, and it passes as soon as the flush stops. You are awake, and you can tell us if you feel it.

It adds a small amount of risk and removes a larger one. The catheter itself carries the same rare risks as any wire or catheter in a coronary artery — spasm, or very rarely a tear — and the extra dye matters if your kidneys are weak. Against that, it prevents wrongly sized and under-expanded stents, which are the failures that bring people back to the cath lab. In complex disease the balance is clearly in favour of imaging, which is why the guidelines say so.

Because an angiogram is a shadow. Dye fills the channel and we photograph its outline from outside, in two dimensions — so branches overlap, bends foreshorten, and an artery that is diseased along its entire length can look deceptively normal because there is no healthy segment left to compare it against. Most importantly, the outline of the channel says nothing about the wall around it. Two blockages that look identical on the angiogram can be soft fat in one patient and rock-hard calcium in another, and they need completely different treatment.

How thick it is. A CT scan or an angiogram can tell you calcium is present; ultrasound can show where it starts but not reliably see through it. OCT measures the calcium's thickness, how far around the artery it wraps, and how long the calcified segment is — and those three numbers together predict whether a stent will fail to expand. When they cross the threshold, the artery is prepared before the stent goes in rather than after it has failed to open.

It means what your blockage is actually made of. A fibrous plaque behaves like scar tissue. A lipid-rich plaque is a pool of soft fatty material under a thin cap — the kind that can rupture and cause a heart attack, and the kind where the cap's thinness is measured in microns. A calcified plaque is bone-hard. In a heart attack, OCT can also distinguish a plaque that has ruptured from one that has merely eroded, and from a spontaneous tear of the artery wall. These are not academic distinctions: erosion is sometimes treated without a stent at all, and a spontaneous tear in a young patient is often made worse by stenting it.

No, and I would not claim otherwise. A short, simple, non-calcified narrowing in an artery of obvious size can be treated well on the angiogram alone. Imaging earns its place where the anatomy is complex — calcium, left main, forks, long lesions, stent failure, an unexplained heart attack — and that is where the guidelines recommend it. Using it everywhere regardless would be padding, not care.

It depends on how weak the kidneys are. OCT needs contrast dye to clear the blood from the light's path, so it adds to the dye load. Where the kidneys cannot take that, IVUS — which uses sound and needs no dye to see — does most of the same job and is the right choice instead. Tell us about your kidney function beforehand and it will be planned around, not discovered on the table.

This is one of the situations where it helps most. A stent can fail for several quite different reasons: it was never fully opened in the first place, tissue has grown through and over it, fresh plaque has formed inside it years later, or a clot has developed. They look much the same on an angiogram and are treated very differently — one needs a balloon to finish opening the original stent, another needs a drug-coated balloon or a second stent. OCT shows which of them you have.

The OCT system in the lab where I work runs Abbott's Ultreon™ 2.0 software. As the pullback finishes, it automatically traces the outer boundary of the vessel and marks the calcium frame by frame, reports the calcium's arc, thickness and length, measures the opening at every point, and expresses the stent's expansion as a percentage. It also rebuilds a fork in the artery in three dimensions. What it does is measure — quickly, consistently, and without the temptation to skip the measurement when the lab is busy. It does not decide. Every automatic tracing is checked before it changes a plan.

No — and sometimes it means the opposite. Imaging tells us what a lesion is and how big the vessel is; whether a narrowing is actually starving the heart muscle is a different question, answered by a pressure wire (FFR or RFR). The two are often used together, and it is not unusual for the combination to end with a decision to treat with medicines rather than a stent.

The imaging catheter is an additional item on your angioplasty bill and cover varies by policy — some plans include it, some treat it as a consumable. We check what your specific policy covers before anything is scheduled rather than leaving you to find out afterwards.