Page 234 - The Vasculitides, Volume 1: General Considerations and Systemic Vasculitis

Polyarteritis Nodosa 209

Figure 4. Multiple renal artery microaneurysms.

Cardiac Manifestations

Cardiac involvement was mentioned in the first publication of PAN [2] that described a
patient with “nodular coronaritis”. Clinical cardiac involvement occurs in 10% of patients
with clinical expression of PAN [35], with an increase to 40% after recognition of radiologic
and electrocardiographic abnormalities, and in 78% of those studied histopathologically [55].
Although one recent series [36] found cardiac involvement in 22.4% of patients with PAN,
this frequency may have underestimated the true occurrence since newer laboratory
investigations were not employed to gauge cardiac involvement. Congestive heart failure, the
main clinical manifestation of cardiac involvement, reflects both vasculitis of the coronary
arteries and its branches with myocardial arteriolar infarcts, and end-organ renovascular or
hypertensive disease.

Cardiomyopathy occurs 3 to 4 months after onset of PAN onset. Despite coronary artery
vasculitis, angina and myocardial infarctions are uncommon. Among 66 postmortem studied
patients, 41 had features of myocardial infarction, of whom three had clinical cardiac
symptoms, and three had coronary atherosclerosis [55]. Coronary angiography and CT of the
coronary arteries demonstrate coronary involvement in most affected patients with clinical
signs of myocardial infarction, and in some, the latter be a result of small coronary artery
vessel vasculitis or vasospasm [56]. Coronary artery aneurysm, notably in children, suggests
Kawasaki disease (KD), however rupture of them is uncommon but severe, because it can
cause a hemopericardium.

There are no current guidelines for the evaluation of coronary artery involvement in
PAN, however cardiac MRI may be promising. Heart murmurs are generally due to anemia
and not endocardial involvement, the latter of which is infrequent in PAN such that its
presence should lead to an alternative diagnosis. Even less common non-specific pericardial

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