Fasting Before Heart Valve Surgery: A Clear Guide

Fasting for this procedure

Valve surgery is carried out under a general anaesthetic, so your stomach must be empty before you go to sleep. Plan to stop all solid food, milk and milky drinks about 6 hours before the time you are told to arrive, and continue with clear fluids only (water, black tea or coffee, clear juice) until around 2 hours before, then nothing. An empty stomach matters here because you will also be connected to a heart-lung bypass machine and ventilator, and it protects your lungs while you are anaesthetised. Many units actively encourage clear fluids up to the 2-hour mark so you are not dehydrated going on to bypass, so don't starve yourself overnight unless your team specifically tells you to. If your child is having valve surgery, follow the 6-4-2 rule (food and formula 6 hours, breast milk 4 hours, clear fluids 2 hours) and use our child fasting calculator to work out exact times.

Medicines to check

Blood thinners need a written plan. Aspirin is often continued right through valve surgery, but clopidogrel, ticagrelor, warfarin, rivaroxaban, apixaban and similar drugs are usually stopped several days beforehand. Never guess — follow the exact stop dates on your medications to stop before surgery plan.

If you take warfarin, you may be admitted early or 'bridged' with heparin injections while it wears off, because stopping it suddenly carries its own risk. Your INR will be checked before surgery.

Diabetes tablets and insulin are adjusted on the day, as you will not be eating. Metformin and SGLT2 drugs are often paused — see diabetes tablets before surgery and bring your insulin and glucose monitor in with you.

Heart and blood-pressure medicines (beta-blockers, statins) are usually taken as normal with a small sip of water on the morning of surgery — ACE inhibitors and water tablets are sometimes held, so confirm each one.

Bring a complete, up-to-date list of everything you take, including inhalers, herbal remedies and supplements, as some (like fish oil and high-dose vitamin E) can increase bleeding.

Have a dental check-up before your surgery date if your team asks — untreated tooth or gum infection can seed a new valve and cause endocarditis, so any work is best done beforehand.

When this surgery may be delayed

A chest, dental or urine infection, or any active infection, will usually postpone surgery — bacteria in the bloodstream can settle on a fresh valve and cause endocarditis.

Your INR (warfarin level) is still too high on the day, meaning your blood would not clot safely for major heart surgery.

A blood thinner such as clopidogrel, ticagrelor or a DOAC was not stopped on schedule, raising the risk of serious bleeding on bypass.

You did not fast correctly and have eaten or drunk milk too close to your slot, which makes the general anaesthetic unsafe.

An ICU or specialist bed is not available, as everyone needs intensive care immediately after valve surgery and the team will not start without one ready.

Reports & documents to carry

All your heart investigations — echocardiogram, angiogram, ECG and any CT or cardiac MRI reports or discs.

Your blood thinner / warfarin plan and recent INR results, plus your yellow anticoagulation book if you have one.

A full list of your medicines and doses, including anything stopped for surgery and when you last took it.

Your dental clearance letter if one was requested, and details of any recent dental treatment.

Diabetes supplies (insulin, glucose meter, sensor), reading glasses, and a small bag for a longer stay including ICU.

What to ask your anesthesia team

Am I likely to have a mechanical or tissue (biological) valve, and will that mean lifelong warfarin afterwards?

Is mine an open-heart or minimally-invasive operation, and how does that change my recovery and time off work?

Exactly which of my blood thinners do I stop, and on which day — and do I need bridging injections?

Do I need a dental check before surgery, and should I sort out any tooth problems first?

How long will I be in ICU and then on the ward, and roughly how many days in hospital should I plan for?

Your prep checklist

Tick things off as you sort them — saved on this device only, nothing is sent anywhere.

A general guide — your hospital's own instructions always come first.

Frequently asked questions

Why does a mechanical valve mean I'll be on warfarin for life?

A mechanical valve is made of durable man-made material, so blood is prone to clotting on its surface. To stop clots forming and causing a stroke or jamming the valve, you take warfarin every day for the rest of your life, with regular INR blood tests to keep it in the right range. A tissue valve does not usually need lifelong warfarin, but it wears out sooner. Your surgeon weighs your age and lifestyle when choosing, so ask which suits you.

Why do I need a dental check before heart valve surgery?

Bacteria from infected teeth or gums can enter the bloodstream and settle on a heart valve, causing infective endocarditis — a dangerous infection that is far harder to treat once you have a new or repaired valve. A check-up beforehand lets your dentist treat any decay, abscess or gum disease while it is still simple. It is much safer to deal with dental problems before surgery than in the weeks just after it, when your valve is most vulnerable.

Can I keep taking my aspirin before the operation?

Often yes. Aspirin is frequently continued right up to and through valve surgery because the protection it gives your heart usually outweighs the small extra bleeding. Other blood thinners — clopidogrel, ticagrelor, warfarin and the newer tablets like apixaban — are different and are usually stopped on a set schedule. Because the plan is individual, follow the exact written instructions from your surgical and anaesthetic team rather than stopping or continuing anything on your own.

Will I really go to intensive care, and how long is the whole stay?

Yes. After valve surgery everyone goes to ICU or a high-dependency unit so your heart, breathing and bleeding can be watched very closely, usually for a day or two. You then move to a normal cardiac ward to build up your strength. A typical total hospital stay is around five to seven days, though it varies with your recovery and whether the surgery was open or minimally-invasive. Full recovery at home takes several weeks more.