Assessment of neutrophil leukocyte infiltration in aortic valves in patients with infective endocarditis

Infective endocarditis (IE) is an inflammatory disease affecting the endocardium, including heart valves. Inflammatory cells, especially neutrophilic leukocyte migration patterns may play a role in remodeling layers of cardiac valves and vegetation formation. We aimed to assess the neutrophils’ infiltration pattern in aortic valve layers in patients with IE and couple these findings to routine laboratory indices. Materials were obtained from nineteen patients diagnosed with IE and undergoing valve surgery. The aortic valve tissues were fixed routinely in 10% neutral formalin, paraffin-embedded, sectioned and stained with hematoxylin and eosin (H&E). Neutrophils were counted semi-quantitively. Clinical and laboratory data were collected from patient medical records. Laboratory indices were correlated to histopathology data. Data were assessed statistically by using SPSS 26.0 version. Five patients (26.3%) had bicuspid aortic valve morphology. Six of nineteen (31.6 %) patients had perforations in aortic valve cusps. Twelve tissue samples (63.2%) presented with calcification nodules, whereas 14 (73.7%) demonstrated ingrowth of blood vessels into the cusp. The free edge of the valve leaflet revealed a larger amount of neutrophils (mean 2.11) invading the cusp when compared to the middle portion (mean 1.63, p<0.001) and base (mean 0.68, p<0.001). Furthermore, the fibrosa layer was more severely infiltrated by neutrophils (mean 1.75) when compared to spongiosa (mean 1.33, p=0.02) and ventricularis (mean 1.33, p=0.04). Preoperative laboratory analysis showed an increase in the C-reactive protein and procalcitonin level (mean 46.25 ± 58.33, and 0.19 ± 1.22, respectively). 1. Neutrophils’ infiltration is more often observed in the free edge and middle portion of aortic valve cusps.2. Fibrosa  layer of the aortic valve are more heavily infiltrated when compared to spongiosa and ventricularis.3. Elevated levels of C-reactive protein and procalcitonin are coupled to neutrophilic infiltration of the aortic cusp.