PARIS — Periodic cardiac evaluations should be routine for all patients with systemic sclerosis, starting at “the first day of the disease.”
Cardiac problems in patients with systemic sclerosis (SSc) were traditionally thought to occur mainly in those with the diffuse subtype of disease, not the limited cutaneous subtype. But with the use of contemporary cardiac evaluation tools, including tissue Doppler echocardiography, myocardial scintigraphy, and cardiac MRI, it has become apparent that coronary lesions occur very early in the course of both subtypes—and are far more prevalent than previously realized, Dr. André Kahan said at the annual European Congress of Rheumatology.
“I would say they are present in close to 100% of patients,” said Dr. Kahan, professor of rheumatology at René Descartes University, Paris.
Subclinical myocardial perfusion abnormalities, diminished coronary reserve, and reduced left and/or right ventricular contractility are common in patients with SSc. The good news is that numerous studies by Dr. Kahan and others have demonstrated that these abnormalities are reversible with high-dose vasodilator therapy using calcium channel blockers or angiotensin-converting enzyme inhibitors. And bosentan has been shown to reverse the early abnormalities.
If the cardiovascular abnormalities aren't treated early, however, fibroblasts become activated, collagen is deposited, and irreversible myocardial fibrosis occurs.
When clinical cardiac disease is present, as in 15%–25% of SSc patients, all-cause mortality is sharply increased. Dr. Kahan cited one international study involving 3,311 SSc patients followed for nearly 20,000 person-years in which clinical cardiac involvement conferred an adjusted 2.8-fold greater mortality (Am. J. Med. 2005;118:2–10).
The coronary disease present in SSc patients is completely different both in site and mechanism from that encountered in rheumatoid arthritis, systemic lupus erythematosus, or atherosclerotic heart disease in the general population. In those cohorts, the large coronary arteries are involved, while in SSc it is the small coronary vessels.
The vascular lesions in SSc patients are vasospasm-induced ischemic reperfusion injuries. Not just the small coronary arteries are affected, but small arteries everywhere else in the body, too, including the digits, pulmonary circulation, and the kidneys. These vascular injuries and the resultant fibrotic changes lead to the major complications of SSc.
Tissue-Doppler echo is now widely available in routine cardiology practice; it provides an excellent noninvasive means of assessing left and right ventricular function. It is far more sensitive than standard echocardiography and should be applied routinely in all SSc patients, in Dr. Kahan's view.
Cardiac MRI is probably the method of choice for evaluating myocardial perfusion in these patients. Scintigraphy has excellent sensitivity, too, but the need to inject radioisotopes is a significant disadvantage over the course of years of repeated testing, he continued.
Diffuse myocardial perfusion abnormalities are extremely common in SSc patients. They can be detected at rest and induced by cold, high altitude, or exercise. This last observation prompted an audience member to ask whether the aggressive exercise program he and his colleagues prescribe for their SSc patients is really such a good idea.
Dr. Kahan replied that his research in the mid-1980s showed that coronary reserve in SSc patients is only half that of normal subjects. For this reason, he counsels his patients to stick to limited exercise relieved by liberal rest periods.
“I tell them to avoid dyspnea. Dyspnea means they've gone much too far. They must not exercise at too high a level because then they may induce ischemia,” he said.
Not just the small coronary arteries are affected, but small arteries everywhere else in the body, too. DR. KAHAN