A cohort study reveals myocarditis to be a rare and life-threatening presentation of large vessel vasculitis

Background The predominant forms of adult large vessel vasculitis (LVV) are giant cell arteritis (GCA) and Takayasu arteritis (TA). Cardiac involvement in LVV is a cause of morbidity and mortality, particularly in TA. Cardiac failure is most commonly secondary to uncontrolled arterial hypertension or myocardial ischaemia. Pulmonary hypertension and aortic valve incompetence following ascending aortic dilatation represent other serious cardiovascular complications. However, cardiac failure as a consequence of myocarditis is rarely reported, principally in single case reports or in autopsy studies. Methods The Imperial College LVV database was, retrospectively, reviewed to identify patients with cardiac involvement at presentation. Patients with evidence for myocarditis were identified. The cardiac presentation, imaging studies and subsequent medical and surgical management were reviewed in detail. Results The cohort included 139 patients with TA and 24 with GCA. Sixteen presented with cardiac failure without a history of ischaemic coronary heart disease, 14 (10%) with TA and 2 (8.3%) with GCA. Cardiovascular disease identified at presentation included aortic regurgitation (n = 11), myocarditis (n = 4) and hypertensive cardiomyopathy secondary to renal artery stenosis (n = 1). Those patients with evidence of myocarditis at presentation (2.8%) underwent transthoracic echocardiography and cardiac magnetic resonance imaging (CMR). These non-invasive techniques were sufficient for diagnosis of clinically significant myocarditis. Furthermore, they were subsequently used to monitor response to treatment, with serial improvement in left ventricular ejection fraction (LVEF) observed in all 4 patients (p < 0.05). Prednisolone plus cyclophosphamide (CyC) therapy was associated with significant improvement in heart failure symptoms and LVEF in 3 cases. In one case where CyC was contraindicated, tocilizumab treatment led to marked improvement in cardiac symptoms. Conclusion Clinically significant myocarditis in LVV remains a rare but serious presentation. Non-invasive imaging techniques offer an alternative to the gold-standard myocardial biopsy. Initial aggressive immunosuppressive therapy is recommended and led to significant improvements in LVEF and cardiac status.