BackgroundThe diagnosis of Immunoglobulin G4 (IgG4)-related disease (IgG4-RD), in general, depends on serum IgG4 concentrations and histopathological findings; therefore, diagnosis of IgG4-RD in cardiovascular organs/tissues is often difficult owing to the risk of tissue sampling.MethodsPrevalence of IgG4-positive lymphoplasmacytic infiltration in 103 consecutive cardiovascular surgical samples from 98 patients with various cardiovascular diseases was analyzed immunohistochemically.ResultsThe diagnoses of the enrolled patients included aortic aneurysm (abdominal, n = 8; thoracic, n = 9); aortic dissection (n = 20); aortic stenosis (n = 24), aortic regurgitation (n = 10), and mitral stenosis/regurgitation (n = 17). In total, 10 (9.7%) of the 103 specimens showed IgG4-positive cell infiltration with various intensities; five of these were aortic valve specimens from aortic stenosis, and IgG4-positive cell infiltration was present at >10 /HPF in three of them. In one aortic wall sample from an abdominal aortic aneurysm, various histopathological features of IgG4-RD, such as IgG4-positive cell infiltration, obliterating phlebitis, and storiform fibrosis, were observed.ConclusionsIgG4-positive cell infiltration was observed in 9.7% of the surgical cardiovascular specimens, mainly in the aortic valve from aortic stenosis and in the aortic wall from aortic aneurysm. Whether IgG4-positive cell infiltration has pathophysiological importance in the development or progression of cardiovascular diseases should be investigated in future studies.

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Aims Recently, liver fibrosis markers, such as the fibrosis-4 index (FIB-4), have been shown to be associated with prognosis in patients with heart failure. The fibrosis-5 (FIB-5) index, which assesses albumin, alkaline phosphatase, aspartate transaminase, alanine aminotransferase and platelet count, is a simple liver fibrosis marker that was reported to be superior to FIB-4 for differentiation of liver fibrosis. This study aimed to compare the prognostic value of FIB-4 and FIB-5 in patients with heart failure. Methods and resultsThe FIB-4 and FIB-5 scores were calculated at discharge in 906 patients hospitalized with heart failure. The patients were stratified into three groups based on their FIB-5 scores: low (n = 303), middle (n = 301), and high (n = 302) FIB-5 groups. The primary endpoint was a composite of cardiac death or rehospitalization for heart failure. The low FIB-5 group was older and had larger inferior vena cava diameters and higher brain natriuretic peptide levels than the other two groups. The primary endpoint occurred in 156 (51.5%), 110 (36.5%), and 54 patients (17.9%) in the low, middle, and high FIB-5 groups, respectively (P < 0.001). On Cox proportional hazard analysis, the low FIB-5 was independently associated with the primary endpoint after adjustment for confounding factors. The association was consistent in both patients with preserved and reduced left ventricular ejection fraction (LVEF), and there was no significant interaction between LVEF phenotypes in terms of the prognostic impact of FIB-5 (P for interaction = 0.311). FIB-5 was superior to FIB-4 as a prognostic indicator of the primary endpoint (continuous net reclassification improvement, 0.530; 95% confidence interval [CI], 0.399-0.662; P < 0.001; integrated discrimination improvement, 0.072; 95% CI, 0.057-0.088; P < 0.001). Conclusions The FIB-5 is a useful risk stratification marker with better prognostic value than FIB-4 in patients hospitalized with heart failure.

A 74-year-old man was admitted for preoperative screening of aortic stenosis. Five months before this admission, he was found to have elevated serum immunoglobulin G4 (IgG4; 2,010 mg/dL). Computed tomography (CT) showed a soft tissue mass surrounding the abdominal aorta, suggestive of IgG4-related periaortitis. CT coronary angiography showed perivascular thickening of the right coronary artery, and subsequent coronary angiography showed a multi-vessel disease. The patient underwent aortic valve replacement and coronary bypass surgery. Immunohistochemical analysis showed IgG4-positive plasmacytic infiltration in specimens from the aortic valve, epicardium, and aortic adventitia, suggestive of the possible role of IgG4-related immune inflammation for the pathogenesis.

The prevalence and extent of immunoglobulin G4 (IgG4)-positive cell infiltration were investigated in 282 surgical samples of aortic wall and aortic valve. Tissue infiltration of IgG4-positive cells was observed in 24 (17.3%) of 139 aortic valve samples and 46 (32%) of 143 aortic wall samples, and the condition of IgG4positive cell infiltration > 30/hpf together with IgG4/CD138 ratio > 40% was observed in 2 (1.4%) of aortic valve samples and 14 (9.8%) of aortic wall samples. Among 275 patients, preoperative serum IgG4 level was available in 48 patients (50 samples), and it was > 135 mg/dL in only one patient. Of these 48 patients with serum IgG4 measurement, 29 patients had aortic valve stenosis and 12 had aortic aneurysm. Compared with 23 aortic stenosis patients without tissue infiltration of IgG4-positive cells in the aortic valve, six patients with IgG 4-positive cell infiltration had a more prevalent smoking history (26% versus 83%) and borderline significantly higher serum IgG4 (median, 24.5 mg/dL versus 55.5 mg/dL), although either preoperative peak pressure gradient between left ventriculum and aorta or aortic valve area did not differ significantly between groups. Compared with six aortic aneurysm patients without tissue infiltration of IgG4-positive cells in the aortic wall, six patients with IgG4-positive cell infiltration had borderline significantly higher serum IgG4 (median, 28.9 mg/dL versus 68.2 mg/dL). The current study showed that tissue IgG4-positive infiltration is not a rare occurrence in the aortic stenosis and aortic aneurysm. Clinical significance of tissue IgG4-postive cell infiltration in these patients requires further investigation.