PXE and the Cardiovascular System
PseudoXanthoma Elasticum (PXE) is a disorder of connective tissue that is associated with various complications with blood vessels. In this issue we will focus on those primarily involving the heart.
PXE is an inherited skin disease that is associated with many systemic manifestations. It is characterised by abnormalities of elastic tissue which prominently involve the heart and blood vessels. Abnormal elastic tissue in arteries becomes calcified and cracks, causing dermatologic, gastrointestinal, cardiovascular, retinal, renal, uterine, bladder, nasal, and joint bleeding. Gastrointestinal bleeding can be life threatening, and severe uterine bleeding during pregnancies has been reported. Retinal bleeding is an important cause of visual loss.
Arteries, including those in the arms and legs, are frequently calcified, and this calcification can appear on x-rays. Narrowing of arteries in the legs may result in pain on walking, a condition called Intermittent Claudication. It is estimated that approximately one-third of patients with PXE experience intermittent claudication. Calcification and narrowing of the arteries to the kidneys can result in elevated blood pressure. Arteries may become so calcified that it may be difficult to feel pulses.
Arteries around the heart, called the coronary arteries, can also become narrowed. This narrowing resembles atherosclerothic heart disease and represents a true “hardening of the arteries.” This has resulted in heart attacks in some patients even at an early age. In teenagers with PXE, there have been reports of sudden death presumably resulting from heart attacks. We are aware of a 13 year old girl who developed angina pectoris (the name for the characteristic chest pain associated with narrowing of the coronary arteries), and there have been documented heart attacks in young teenagers with PXE. Despite these grim reports, most patients with PXE have a life span that is close to normal, and there are patients with PXE who are at least in their 80’s alive today.
Some patients with PXE will first present with cardiac symptoms. There is a report of a 27 year old female physician who did not have a history of PXE who underwent four-vessel coronary artery bypass surgery for narrowing the coronary arteries.
Biopsy of the arteries at the time of surgery revealed calcification of elastic tissue typical of PXE. Angioid streaks, a typical retinal finding in pseudoxanthoma elasticum, was seen in this patient, and skin biopsy of normal appearing skin showed the characteristic changes of PXE.
The same report reviews three other patients who have evidence of PXE and first developed cardiac symptoms despite the absence of typical skin lesions. All of the reported patients did not have risk factors for early heart disease such as family history of heart disease, high blood pressure, diabetes, markedly elevated cholesterols or a strong history of cigarette smoking. It has therefore been suggested that a diagnosis of PXE should be considered in young patients with cardiovascular disease, especially if the patients do not have a history of other cardiac risk factors.
The heart valves also have significant amounts of elastic tissue and can become calcified. A number of heart valve abnormalities have consequently been reported. The most common heart valve abnormality in PXE is called mitral valve prolapse. While other valvular abnormalities have been documented, mitral valve prolapse effects up to 70% of patients with PXE. Heart valve abnormalities are detected with a simple test called echocardiography, a non-invasive test that does not require x-rays. This test evaluates the heart valves using a technique similar to radar. Since up to 10% of normal women may have mitral valve prolapse, this heart valve abnormality should not be considered dangerous. Heart valve disorders can, however, predispose to endocarditis, and infraction of the valves. We are aware of two patients with PXE who developed endocarditis and at least one of them subsequently went on to develop seriously impaired function of the heart valves.
What can I do?
Since many heart valve infections occur after dental work it has been suggested that patients with PXE, who have heart valve abnormalities that might predispose them to infection, be preventively treated with antibiotics before, and immediately after, dental work. To prevent athero sclerosis that may complicate the calcification of coronary arteries, a heart-wise life style has been suggested. As many as a one third of patients with PXE have elevated fat in the blood and therefore a low cholesterol diet has been suggested. Avoidance of cigarette smoking and control of diabetes and high blood pressure are important. Non-strenuous aerobic exercising can be beneficial, but should be reviewed with a physician.
Since it has been suggested that estrogens exacerbate PXE, some physicians have advised avoiding oral estrogens.
Aspirin has been suggested to prevent the complications of heart disease, but patients with PXE have a significant bleeding tendency that is markedly exacerbated by aspirin ingestion. It is therefore suggested that aspirin be avoided in patients with pseudoxanthoma elasticum.
There are many ways to control or partially avoid high blood pressure and treat intermittent claudication. The most basic factors are exercise, diet, and weight control. First, exercise may help prevent aching in the legs which results from narrowing blood vessels. It can also help improve the patient’s general health. Secondly, patients should avoid blood thinners such as aspirin and non steroidal anti-inflammatory drugs. Serum lipids should be checked to avoid unnoticed elevated levels of cholesterol. Lastly, check stools for blood especially if you are having an upset stomach.