What is Cardiac Syndrome X (Microvascular Angina)?
Cardiac Syndrome X (CSX) is a term created by Harvey Kemp in 1973. It’s a condition that includes typical or unusual chest pain but doesn’t show any major abnormal heart vessel conditions when examined through an angiogram- a special X-ray test. It’s also known as microvascular angina or chest pain with normal coronary arteries. These conditions occur most commonly in women around the time of their menopause.
It used to be thought of as a harmless disease. However, recent studies suggest that individuals with CSX may experience serious heart-related issues and a lower quality of life. Diagnosing this disease can be tricky because it’s often identified only after ruling out other conditions. Treatment is also challenging because the main cause of CSX is still not fully understood. It’s thought to happen because of small blood vessels’ dysfunction in the heart, leading to a lack of blood to part of the heart (myocardial ischemia) and irregular heart pain sensitivity.
The observable symptoms of CSX are thought to come from extreme sensitivity of the heart muscle. Standard treatments for reducing this heart pain or myocardial ischemia – such as beta-blockers, nitrates, or calcium channel blockers – can be used to manage CSX. Other medications like ACE inhibitors, statins, and certain heart pain medications like ranolazine may also be helpful. Pain management medications like tricyclic antidepressants (TCA) and derivatives of xanthine have been reported to be effective. Lifestyle changes and various treatments like cognitive-behavioral therapy (a type of talk therapy) and neurostimulation (using electric currents to stimulate nerves) may also be considered.
What Causes Cardiac Syndrome X (Microvascular Angina)?
The exact causes and progression of CSX, also known as microvascular angina, aren’t fully understood. However, various theories and mechanisms have been suggested. A key possibility is a dysfunction in the tiny blood vessels of the heart (microvascular dysfunction), which limits blood flow and may lead to typical or atypical chest pain (ischemia or angina). Another theory centers on an increased sensitivity to heart pain, known as “hyperalgesia.” This happens in individuals who experience chest pain and microvascular dysfunction after physical strain like exercise, even when there’s no apparent damage to the heart muscles.
Some patients with CSX might have both microvascular dysfunction and heightened cardiac pain sensitivity, while others might have different underlying causes. People diagnosed with CSX are about 30% more likely to have underlying metabolic health conditions than the general population (8%). Factors that might contribute to the development of CSX and coronary microvascular dysfunction include insulin resistance and high blood sugar levels, changes in red blood cells’ sodium-hydrogen exchange, chronic inflammation marked by elevated levels of C-reactive protein (CRP), and dysfunction in the smooth muscle cells lining the blood vessels or elsewhere in the body.
Risk Factors and Frequency for Cardiac Syndrome X (Microvascular Angina)
Cardiac Syndrome X, or CSX, is a condition that primarily affects women, particularly those who are in their perimenopausal or postmenopausal years, between the ages of 45 to 55. On average, women are typically diagnosed around the age of 48.5.
Although the exact prevalence of CSX is not currently known, studies suggest that women represent about 70% of all cases. Additionally, around 10% to 20% of people who undergo a coronary angiography, which is a test to check the heart’s blood vessels, are found to have CSX.
In a large study of 886 people with chest pain who were suspected of having a heart attack, 41% of the women showed non-significant findings in their coronary vessels when they underwent a coronary angiography. This percentage was much higher than the 8% among men in the same study group.
Signs and Symptoms of Cardiac Syndrome X (Microvascular Angina)
Cardiac Syndrome X (CSX) is a condition diagnosed mostly by ruling out other illnesses. It’s usually recognized by repeated chest pains similar to angina, but doesn’t show more than 50% blockages in heart scans. Chest discomfort with this syndrome could happen during physical activities like exercising and might continue afterwards. The pain may also occur when a person is at rest. It’s often described as being centered behind the breastbone and can spread towards the left arm.
Before invasive and non-invasive testing is done, a complete medical history and physical examination should be performed. Doctors should carefully analyze potential causes of the patient’s symptoms. It’s essential to rule out chest pain from non-heart related causes, including emotional stress. Risk factors for heart disease should be thoroughly evaluated in the patient.
- Repeated chest pains similar to angina
- No significant blockages seen in heart scans
- Chest discomfort during and after exercise
- Chest pain even at rest
- Pain centered behind the breastbone, spreading towards the left arm
Testing for Cardiac Syndrome X (Microvascular Angina)
The first step in assessing Cardiac Syndrome X (CSX) would typically include gathering patient history and carrying out a physical examination. This is usually followed by non-invasive tests. Prior to any invasive procedures, an exercise tolerance test (ETT) or an ultrasound of the heart known as dobutamine stress echocardiogram (DSE), should be carried out. It’s worth noting that patients are often found to have heart rate irregularities during such exercises or monitoring.
In certain cases, severe chest pain during a DSE, indicative of blood vessels not dilating as they should, alongside irregularities in the heart rate, could suggest CSX. A subsequent ETT can be carried out after giving the patient short-acting nitrates (a kind of medicine). Although these medicines help to relieve chest pain in patients with coronary artery disease, they have been found to not always alleviate the pain in CSX patients.
Coronary angiography, an X-ray of the coronary arteries, can be used to accurately understand if there are any blockages present in the heart’s blood vessels. Generally, disease in the coronary artery is defined as 50% or more of the left coronary artery being obstructed, or a 70% or more blockage of a coronary artery wider than 2 mm. CSX is mainly diagnosed based on exclusion – patients present with typical or atypical chest pain, heart rate irregularities, but no substantial blockage of over 50% in the heart arteries as shown on angiography.
Another invasive procedure that can shed light on the health of the blood vessels involves cardiac catheterization and Doppler guide-wire. This procedure checks how well the heart’s blood vessels increase their blood flow after being given specific medicines. Also, non-invasive examinations such as brachial artery reactivity and peripheral arterial tonometry can be used to evaluate the overall function of the blood vessels.
Treatment Options for Cardiac Syndrome X (Microvascular Angina)
Managing patients suspected of having CSX, or cardiac syndrome X, can be challenging, as we don’t fully understand what causes it. There are no standardized guidelines for treating CSX. Instead, treatment methods usually get decided on a patient-by-patient basis. These can include medication to prevent heart artery problems, painkillers, non-medication therapies, and lifestyle changes.
Conventional medications for heart artery problems include beta-blockers, statins, calcium channel blockers, ACE inhibitors, and a type of medicine called antianginal drugs such as ranolazine.
Patients with CSX who are experiencing chest pain similar to what occurs during a heart attack should consider therapy with sublingual nitrates (a type of medicine taken under the tongue). There’s no concrete evidence to show the effectiveness of nitrates in CSX patients, but they, along with beta-blockers, are the standard treatment. Specific kinds of beta-blockers have been reported to be effective in 75% of CSX patients, improving exercise ability and symptoms.
Calcium channel blockers may be an alternative to beta-blockers if the latter aren’t working. While these drugs have been shown to improve exercise tolerance and minimize chest pain episodes, they haven’t been as effective as beta-blockers in CSX patients. Ranolazine, a newer type of medication used for chronic chest pain, can also be an effective treatment option.
Statins and ACE inhibitors could also be effective in CSX patients. Both medications improve the ability of the vessels to enlarge and help control the tone of the small heart arteries.
As CSX might be related to a heightened perception of pain, medications like painkillers may help. Treatments such as xanthine derivatives, aminophylline, and therapies like neural electrical stimulation have been proposed for certain patients. These treatments can also help manage the pain sensitivity that’s been observed in CSX patients.
Some other suggested medications include antidepressants like tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs). One kind of TCA, imipramine, has been reported to decrease chest pain frequency by about 50%. However, the use of imipramine in CSX management has been controversial due to its possible side effects.
In addition to drug treatments, lifestyle changes should be encouraged. These can include exercising more, not smoking, losing weight, and modifying diet. Improving lifestyle habits has been shown to positively influence the function of the endothelium (the inside lining of blood vessels), reducing the risk of adverse heart events and CSX.
What else can Cardiac Syndrome X (Microvascular Angina) be?
If a patient appears to have heart problems, doctors might use imaging tests like an echocardiogram to look for physical issues or inflammation. If it seems like there’s a problem with blood vessels supplying the heart, both large and small vessels will be examined closely. Vasospastic angina is a common condition where the larger blood vessels of the heart have spasms, often causing chest pain when a person is resting.
These spasms might be triggered by drugs like ergonovine or acetylcholine, or even accidentally during imaging tests. Mechanical irritation from inserting a catheter into the heart’s blood vessels can also cause spasms. Changes that do not show a lack of blood supply, such as reversible ST-elevations, can be detected on an electrocardiogram (ECG).
If a person describes heart pain during a catheterization procedure, it’s likely that a catheter-induced spasm has happened, and vasospastic angina might be the diagnosis. Treatment with drugs that dilate the outer blood vessel layer, like nitroglycerin, might be started. It is important to identify whether the spasms come from atherosclerosis or from catheter-induced spasms because the arterial pressure could appear different due to a narrowing of the diameter of the vessel opening.
If a patient shows signs indicative of cardio ischemia (a condition where not enough blood gets to the heart) but there’s no evidence of blocked coronary arteries in the imaging tests, an issue with the function of small blood vessels that supply the heart could be causing the chest pain. Before concluding that a person has this small-vessel condition (also known as CSX), it’s critical to rule out other conditions, such as hypertension-induced heart disease, amyloid induced cardiac disease, Takotsubo heart disease, Anderson Fabry disease, and coronary slow-flow phenomenon (also known as cardiac syndrome Y), a condition where blood flow is impeded during a procedure to open up blocked blood vessels.
Doctors also need to consider non-heart related reasons for chest pain. These could be caused by mental health issues like anxiety and depression, digestive system diseases, liver conditions, lung problems, muscle and bone issues and even other disorders like Tietze syndrome – a rare inflammatory disorder characterized by chest pain and swelling of the cartilage of one or more of the upper ribs.
What to expect with Cardiac Syndrome X (Microvascular Angina)
Long-term effects of CSX, a heart condition, can be influenced by factors such as chest pain, weak responses of small blood vessels in the heart to a substance called acetylcholine, the severity of dysfunction in the blood vessel lining, and a shortage of blood supply to the heart. Poor functioning of the blood vessel lining and how well small blood vessels in the heart respond to acetylcholine can predict how the condition may progress. Severe problems could lead to plaque build-up and acute heart issues. Patients diagnosed with CSX may often experience unfavourable heart events, multiple visits to the hospital, a lower quality of life, and poor future health outcomes.
CSX symptoms seem to lessen in about 30% of people but may steadily get worse in about 20% of patients. A study on a group of women found that 45% with chest pain showed no blockage in the heart’s arteries by imaging. But they reported continuous chest pain for over a year. The same study reported these subjects had double the risk for serious heart events like heart attacks, strokes, heart failure, and death.
People with advanced CSX may have regular, long-lasting chest pain that could occur with less physical exertion or even at rest. Some may find it resistant to drug treatments, which further reduces quality of life. Such patients may need serious diagnostic procedures that might potentially lead to disability.
Possible Complications When Diagnosed with Cardiac Syndrome X (Microvascular Angina)
It was once believed that Cardiac Syndrome X (CSX) was a fairly harmless condition. However, recent studies have shown that women with chest pain similar to angina, but who show no signs of narrowing arteries on scans, can still experience serious heart-related incidents. These can include heart attacks, strokes, heart-related deaths, mortality from all causes, and being hospitalized due to heart failure.
CSX can also greatly affect a patient’s quality of life and their ability to carry out everyday tasks. Diagnosing CSX can be complex and may require a lot of tests and assessments, which can be both time-consuming and costly. Another challenge is finding the right medication that is effective, as traditional methods for managing chest pain like angina often do not work. As a result, symptoms of CSX often last a long time, leading to hospitalizations, hindering daily activities, and even affecting the ability to work.
While most people with CSX have a good prognosis, the condition is quite common and can often lead to repeat hospitalizations due to recurring chest pain. In around 30% of patients, symptoms are reported to lessen, but in 10% to 20% of cases, they can get progressively worse. Those who experience a worsening condition often face diagnostic challenges and procedures, potentially leading to disability.
Preventing Cardiac Syndrome X (Microvascular Angina)
Patients need to be extensively informed about CSX and how it could affect them. It’s important that they fully commit to taking their medicines as prescribed and making healthy changes in their daily lives. Patients should also be made aware that diagnosing and treating CSX can be challenging since we don’t fully understand what causes it. Based on the latest research, patients should be informed about the potential long-term complications and future outlook of their condition. In addition to this, patients should be taught how to manage any other health conditions they have, and any conditions related to their metabolism, as these could further lead to harmful heart-related incidents.
