Finding a narrowing or blockage in a coronary artery naturally causes concern. When coronary angiography or coronary CT angiography reveals a severe narrowing, one of the questions patients most often ask is:
“Doctor, if my artery is blocked, why don't we open it straight away?”
The answer is not as straightforward as it may seem. In cardiology, treatment decisions are not based solely on how narrow an artery has become.
What matters is the benefit an intervention can offer the patient.
Why Do We Open Coronary Arteries?
The treatments we use in cardiology have two main aims:
- To prolong life: To reduce the risk of serious events such as heart attack, heart failure or death.
- To improve quality of life: To relieve symptoms such as chest pain, breathlessness and reduced exercise capacity.
Opening an artery simply because it is blocked is not, in itself, a treatment goal.
We expect coronary revascularisation with a stent, balloon or bypass surgery to provide a meaningful benefit for the patient.
The first question is therefore whether the blockage is acute or chronic.
An Artery Blocked During a Heart Attack: An Emergency
Many heart attacks occur when an atherosclerotic plaque inside a coronary artery ruptures or its surface is disrupted, leading to the formation of a blood clot. The clot can suddenly reduce or completely stop blood flow to the heart muscle.
In ST-elevation myocardial infarction (STEMI) in particular, opening the blocked artery as quickly as possible is vital.
Delays can lead to greater damage to the heart muscle.
In suitable patients, emergency coronary angiography and percutaneous coronary intervention (balloon angioplasty and stenting) help preserve heart muscle and improve survival.
However, the artery is not completely blocked in every acute coronary syndrome. In conditions such as NSTEMI, the need for an intervention and its timing depend on the patient's clinical risk.
In other words, acute coronary syndromes cannot be assessed in the same way as chronic narrowings that develop over many years.
Chronic Coronary Syndrome: Does Every Narrowing Need Treatment with a Procedure?
Many coronary artery narrowings develop over years.
During a process called atherosclerosis, plaques made up of cholesterol and other substances accumulate in the artery wall. Over time, these plaques may restrict blood flow.
This clinical setting is known as chronic coronary syndrome.
Patients may experience chest pain, chest pressure or breathlessness, particularly during exertion.
However, not every severe narrowing causes symptoms.
Some patients have no significant symptoms despite coronary CT angiography showing a narrowing of 70%, 80% or even 90%.
There is an important point here:
The percentage of narrowing alone does not determine whether a stent is needed.
The location of the artery, the amount of heart muscle it supplies, the effect on blood flow, the patient's symptoms and other medical conditions must all be considered together.
If I Have No Symptoms, Does That Mean I Don't Need a Stent?
Having no symptoms does not mean that coronary artery disease is unimportant.
However, the absence of symptoms during everyday activities is one of the important factors we consider when deciding on revascularisation.
For example, in someone who can climb stairs, walk and carry out daily activities comfortably, it may not be appropriate to recommend a stent solely on the basis of the percentage of narrowing seen on angiography.
There are important exceptions.
In high-risk anatomical situations, particularly left main coronary artery disease, or in some patients with impaired heart function and extensive coronary artery disease, the potential prognostic benefit of revascularisation may need to be considered even without symptoms.
Decisions therefore need to be individualised.
Having no symptoms does not mean that no treatment is needed; not needing a stent does not mean leaving the disease untreated.
What If the Artery Is Completely Blocked?
This brings us to a more specific condition: chronic total occlusion (CTO).
A chronic total occlusion is a coronary artery that has been completely blocked for a long time. The term generally refers to a complete blockage thought to have been present for at least three months.
Unlike a sudden blockage, a chronic occlusion may have hardened and developed a more complex structure over time.
CTO procedures may therefore require greater technical experience, specialised wires, microcatheters and different procedural techniques compared with standard coronary stenting.
The procedure may also be more difficult and carry a higher risk of complications.
Why, then, might we want to open a completely blocked artery despite these challenges?
Does Opening a CTO Prolong Life?
The answer is different from what many patients expect.
Current randomised clinical trials have not conclusively demonstrated that CTO interventions prolong patients' lives.
However, in appropriately selected patients, particularly those whose symptoms persist despite treatment, opening a CTO can reduce chest pain and improve exercise capacity and quality of life.
One of our most important goals in CTO intervention is therefore to relieve the patient's symptoms.
In some patients, collateral blood vessels can partly compensate for a completely blocked artery. Some blockages may also affect a relatively small area of heart muscle.
In these situations, the benefit of an intervention may be limited if the patient has no symptoms.
However, the presence of collateral vessels does not always mean that the heart muscle receives enough blood. Decisions take the patient's clinical condition into account, alongside assessments of ischaemia or myocardial viability when needed.
Not every artery we can technically open needs to be opened.
Particularly for complex and higher-risk procedures, we want to be confident that the expected benefit outweighs the procedural risk.
How Is the Disease Treated If No Stent Is Inserted?
The treatment of coronary artery disease is not limited to stents or bypass surgery.
Medication and control of risk factors are fundamental to long-term management.
Lowering LDL cholesterol, stopping smoking, controlling blood pressure and diabetes, appropriate physical activity and a healthy diet are all important parts of treatment.
Antithrombotic and antianginal medicines may also be used according to the patient's clinical circumstances.
These treatments aim not only to relieve symptoms but also to reduce the risk of future cardiovascular events.
Not having a stent therefore does not mean that the patient is not being treated.
Conclusion: Treat the Patient, Not Just the Artery
When a narrowing or complete blockage is found, treatment decisions should not be based solely on the angiogram or the percentage of narrowing.
While prompt intervention can save lives during an acute heart attack, chronic coronary syndromes require a more detailed assessment.
The patient's symptoms, coronary anatomy, heart function, other medical conditions and the potential benefits of a procedure must all be considered together.
Remember: an artery is not opened simply because it is blocked. What matters is whether opening it will provide a real benefit for the patient.