Acute dilated cardiomyopathy in the setting of catastrophic antiphospholipid syndrome and thrombotic microangiopathy: A case series and review

Abstract

Catastrophic antiphospholipid antibody syndrome (CAPS) is a rare form of antiphospholipid syndrome, an autoimmune condition characterized by vascular thromboses, pregnancy loss, and antiphospholipid (aPL) antibodies. Diagnosis of CAPS relies on thrombosis of at least three different organs systems over 1 week, histopathological evidence of small vessel occlusion, and high aPL antibody titers. In a subset of precipitating circumstances, activation or disruption of endothelial cells in the microvasculature may occur along with cardiomyopathy. We present two cases of CAPS-associated dilated cardiomyopathy at our institution, focusing on disease management, pathophysiology, and treatment. These patients were of Southeastern Asian descent, raising the possibility of genetic polymorphisms contributing to the development of cardiomyopathy. Both met CAPS criteria and both demonstrated clinicopathologic thrombotic microangiopathy (TMA) and complement activation and developed severe dilated cardiomyopathy with shock. Complement activation plays an important role in the development of CAPS and may be important in the pathogenesis of CAPS-associated cardiomyopathy. Clinical suspicion for TMA as a pathophysiologic mechanism of unexplained heart failure in CAPS is important and increased awareness of cardiac side effects is necessary so that early treatment can be initiated to halt further cardiac and systemic complications.

Keywords: atypical hemolytic uremic syndrome; cardiomyopathy; catastrophic antiphospholipid antibody syndrome; complement; thrombotic microangiopathy.

FIGURE 1

Patient 1 cardiac MRI. A, Serial short axis delayed contrast enhancement images from base to apex. Black arrows demonstrate areas of late gadolinium enhancement. Purple arrow demonstrates an apical thrombus. B, Left panel: Four chamber delayed contrast enhancement image; right panel: Two chamber delayed contrast enhancement image. Black arrows demonstrate areas of late gadolinium enhancement

FIGURE 2

Patient 1 Pathology findings. A, HE heart myocyte: H&E‐stained section displays myocyte disarray and hypertrophy. B, HE kidney: H&E‐stained section demonstrates marked mesangial expansion, glomerular congestion, and fibrin thrombi within the glomeruli and arterioles. C, Trichrome kidney: Trichrome stained sections display glomerular congestion, mesangial expansion, fibrin thrombi, interstitial fibrosis and tubular atrophy, and arteriolar medial hyperplasia