Pheochromocytoma and Catecholamine-Mediated Cardiac Inflammation, Fibrosis, and Dysfunction
What is the nature of cardiac involvement due to pheochromocytoma, as characterized by cardiac magnetic resonance imaging (CMR)?
The authors conducted a prospective study characterizing the cardiac phenotype in patients with pheochromocytoma using CMR. Left ventricular ejection fraction (LVEF), strain, and degree of fibrosis and inflammation were measured. Patients had a new (n = 29) or previous (n = 31) diagnosis of pheochromocytoma without known cardiac disease. There were 51 healthy age- and sex-matched controls and 14 controls with essential hypertension.
Patients with newly diagnosed pheochromocytoma had a lower LVEF compared to healthy and hypertensive controls (60% ± 9% vs. 67% ± 4% vs 67% ± 4%, respectively, p < 0.05), with 38% of the cohort having LVEF <56%. LVEF improved in patients after resection of their pheochromocytoma (60% ± 9% to 63% ± 5%, p < 0.03). Peak systolic and diastolic circumferential strain rates were lower in patients with pheochromocytoma compared to controls. Newly diagnosed pheochromocytoma patients had an LV mass index similar to control subjects. Myocardial fibrosis, measured by late gadolinium enhancement (LGE) imaging, was significantly increased in patients with newly diagnosed (59%, n = 17) and surgically treated pheochromocytoma (19%, n = 6). Areas of LGE were small in both groups (median 5% and 2% of myocardium) and did not follow a vascular distribution. Finally, using the authors’ previously established criteria for detecting myocarditis with native T1 mapping, there were significant areas of inflammation in newly diagnosed and treated pheochromocytoma patients compared to healthy and hypertensive controls.
In this prospective study of 60 patients with pheochromocytoma, cardiac involvement, as evidenced by LV dysfunction, strain abnormalities, inflammation, and fibrosis, is frequent and persistent after surgical treatment. These changes extend beyond those seen in subjects with hypertensive heart disease and suggest a role for catecholamine-mediated cardiac toxicity.
This CMR study of patients with pheochromocytoma demonstrates that cardiac involvement is common and persists after treatment. Abnormal myocardial strain, fibrosis, and inflammation are subtle and may not be detected by other imaging techniques. Studies with larger patient populations are required to see if specific CMR findings are associated with long-term prognosis in patients with pheochromocytoma.
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