Cardiac Syndrome X after CABGx3

[mijmalu]

Had CABGx3 in January 2012. Was in cardiac rehab for 3 mos (til May 2012) with no issues. Afterwards, I was on a program of walking 2 - 3 miles at home (still no chest pain), 3 to 4 days a week, until November 2012, when knee problems caused me to stop. Began walking again in February 2013 but noticed chest pain each time within the first 10 mins. Cardiologist did a nuclear stress test that showed ischemia in the front of my heart, so he ordered an angiogram (expecting to find at least one of the grafts was blocked). The angiogram came back clear (all 3 grafts were "golden" as he put it). He doesn't seem to have an answer as to why I suddenly can't walk more than 10 min without bad chest pain. He prescribed Imdur and gave me nitro pills that I'm supposed to take for it. The only time I have this is when I exercise and I've found that as soon as I stop, the pain goes away within a minute or less. Dr mentioned Cardiac Syndrome X and said that that is probably what's going on. He said I am able to exercise as much as I want (taking nitro for pain management) and that CSX was not life threatening (if I could cope with the pain). Does this sound right? How could a nuclear stress test show Ischemia (after CABGx3) but the angiogram be all clear, and I still have chest pain that I didn't have for 9 mos after the CABG? Help. Very frustrated and actually afraid to exercise. BTW, took a nitro pill for the first time last week for chest pain during my walk. It didn't help.

[CCFHeart MD23]

Dear mijmalu,

Chest pain after bypass surgery is common and can cause significant limitation and anxiety. I can understand your frustration and hope to help with some information and suggestions for your future heart care.

I would first like to focus on some of the good news associated with your story. Firstly, your cardiologist has taken your pain seriously and investigated appropriately with a nuclear stress test and a coronary angiogram. The second piece of good news is that your coronary angiogram was “clear”, meaning that you do not have any significant narrowings or blockages in your new bypass vessels. I am also pleased to hear that you have attended cardiac rehabilitation and appear to be motivated to continue with regular exercise.

So why are you experiencing pain? Cardiac syndrome X is certainly one possibility and I will share what I know about this condition shortly. However it is also important to return to the basics and make sure that we are not missing alternative causes for chest pain. Possibilities include musculoskeletal pain at the site of your heart surgery (particularly in the midline) – this is worse with exercise, worse when pressure is applied to the area from which pain is arising, and improves with rest and paracetamol. The wires used to close the chest can also cause discomfort – again this pain is worse with pressure overlying the affected area. A CXR may demonstrate a fractured wire. Gastrointestinal reflux or heart-burn is not uncommon and can be triggered by aspirin and other heart medications which aim to reduce clotting in the heart. This pain is a central burning or heat made worse with spicy or fatty meals. Poorly controlled asthma can cause chest tightness – this would be more likely in patients with abnormal lung function tests and/or a history of allergy and eczema. In other cases, the chest discomfort patients are experiencing is not angina but more a reflection of deconditioning post surgery.  Anemia is not uncommon after heart surgery and can be excluded with a complete blood count.  I suspect your cardiologist has completed a thorough assessment for these alternative causes but I think it is always important to make sure that we are not missing an alternate cause.

Ongoing modification of cardiac risk factors also remains very important, including excellent control of blood sugar in diabetics, blood pressure, and cholesterol. Needless to say, it is critical that patients stop smoking as continuing to smoke increases the chance of further heart attacks, stroke, and progression of coronary disease (amongst other things).

Assuming that all of your investigations have been otherwise normal, it is possible that you do have ‘Cardiac Syndrome X’. Your bypass surgery addressed the problem of narrowings or blockages in your large coronary vessels. Just like the branches of a tree, the coronary vessels branch out and become smaller and smaller with each branch. Cardiac Syndrome X is thought to arise due to disease in these small branches and vessels. Patients with CSX report chest pain with exercise and abnormal exercise ECG / nuclear medicine tests. However, their coronary angiograms are ‘clear’. Although the coronary angiogram rules out major narrowings or blockages it is not uncommon for slow blood flow to be present in the small branches of the coronaries and so in reality the angiogram isn’t completely normal. The good news is that not having narrowings or blockages in your major coronaries does put you in a lower risk category. Further evaluation of your risk would require information such as your family history and the presence of reduced heart function, changes in rhythm, and other medical conditions.

So what treatment options are available for cardiac syndrome X? Our knowledge of small vessel disease is constantly evolving. It is standard practice for cardiologists to trial a nitro- patch or spray in patients with coronary disease and chest pain. However, a lack of response to nitrates, or even a worsening of symptoms, signals a need for your treatment to be reviewed. Doctors rely on patients to update us on what is and isn’t working so that we can land on the best treatment for each patient that we see. To help communicate your symptoms a patient diary can be helpful in which you keep track of your symptoms and what you were doing over a period of a few days to a week (I wouldnt recommend any longer than that). Keep track of when the pain occurred, where you felt it, what you were doing at the time, what helps reduce the pain (i.e. rest) and what makes it worse (i.e. exercise, stress). Write down what happens with each nitro that you take: did it help or make it worse? I would recommend you take this information to your next appointment along with your top 5 questions, starting with the question that is bothering you most – i.e.  Could exercise actually be harmful or lead to something bad happening?

There is some evidence that the small vessels in CSX may have a blunted response to nitrates. In some patients with CSX, nitrates can actually increase chest pain. Treatments that have been shown to reduce angina in patients with CSX include beta blockers, calcium channel blockers, nicorandil, enalapril, and trimetazidine. The fact that there is a list of potential treatments should come as good news to you as it suggests that there a number of options for treating chest pain in CSX. Heart rate control is often the target of treatment – it may be worthwhile you recording your heart rate over 1 minute after you have exercised to see how it responds to exertion. This information will be useful for your doctor. Remember that any prolonged or severe chest pain lasting longer than 5 minutes and not responding to nitrates and rest requires immediate medical attention by calling for an ambulance.

I hope that this information is helpful.

Take care and good luck.

[ed34]

I'm sure that an expert will reply to this soon, but in the meantime let me give you something to think over. The pain you are feeling could be the cardiac muscle, and not necessarily causing damage during exercise. It has been realised that in many cases, the cardiac muscle seems to become more sensitive, registering distress when it really doesn't need to. HOWEVER, what troubles me is that the nuclear test revealed ischemia, but the angiogram did not. This is nothing unusual, because the nuclear test shows the oxygen infusion at cell level, the Angiogram can only see arteries of a given size upwards. An Angiogram will not show detail of arterioles or capillaries. I don't think that capillaries will carry the normal variety of heart disease because they don't really have any 'wall', they are virtually transparent. Arterioles can become diseased and this is MVD. So, there is no confusion. Nitro will dilate the Arterioles and relieve pain, but they won't dilate Capillaries, they need to remain the same size for gas exchange, red cells squeeze through these in single file. So if the Nitro is working, then I would guess your disease has established itself in the tiny arteries, not the larger ones seen on an angiogram. Another thing to consider, and I know this is getting complicated but hang in there, is the possibility of collaterals. Perhaps before your bypass you had developed some collateral feeds and they stayed open due to your exercising. Your heart could have adjusted due to the difference in pressure around your coronary arteries (ie the addition of new clear pathways for the blood), closing those collaterals. The important effect of these is virtually never taken into account before decisions are made for revascularization. In many cases the patient ends up feeling worse, because the collaterals close. It seems odd I know, you would think that a better blood supply through the major arteries would improve matters, but in many cases it doesn't. If you are showing ischemia, then perhaps there is a good chance that those collaterals will re-open, if the bypass grafts haven't removed that opportunity. It really can be a very complex picture to deal with.

[mijmalu]

Thank you. You're right. It is complicated, but I'm able to follow the reasoning. The thing that has me baffled is that this pain should have been present during the months after the CABG, and not a year later. I would think that MVD would not suddenly develop in a month or two. There was no  exercise-induced angina for months after the CABG; and then BOOM, after a few month layoff it starts up the same way it was prior to the CABG. Thank you for your response. I will await further responses (if any) and will probably seek a second opinion from another cardiologist.

[ed34]

Here is something else for you to consider. A clear looking artery does not mean it is in good shape at all. I know it sounds nuts, but this happened to me three years ago. Angina returned and I was on the Angio table with my arteries looking clear. Not a sign of any blockages. I had just been reading about something called FFR (fractional flow rate) which is a tiny sensor on the end of catheter which relays the flow rate of blood around it back to the cardiologist. The cardiologist was just going to send me to recovery and I said "what about doing FFR?" and to my surprise he said "what a great idea". He started at the top of my left circumflex and this is where the base figure was taken, I believe it was .8 or something. Halfway down the vessel it suddenly dropped to 0.4 but there was nothing there, the vessel looked great. He put a stent in the area and then it raised to .8 but below the stent it dropped again to .4 This was becoming a mystery, so he put another stent below the first one and again it raised to .8 My reading was now .8 all the way down, yet visually nothing was wrong. So obviously invisible defects in the artery lining can cause enough turbulence to interrupt the blood flow. My angina vanished. I then asked "Please be honest, if you didn't perform ffr, what would you have diagnosed" and he replied SYNDROME X.