Immunocompetent cells in durable ventricular assist device-implanted non-ischaemic dilated cardiomyopathy

Abstract

Objective: Because the presence of immunocompetent cells in the myocardium is associated with the pathological stage and/or myocardial viability, we explored relationships between functional recovery after left ventricular assist device implantation and the distribution of immunocompetent cells in non-ischaemic dilated cardiomyopathy patients.

Methods: We reviewed 50 consecutive dilated cardiomyopathy patients implanted with HeartMate II at our institute between April 2013 and December 2018 who were treated with optimal medical therapy during left ventricular assist device support. Patients were stratified by improvement of the left ventricular ejection fraction at 6 months after implantation: ≥ 10% increase (Gr ≥ 10%), 5-10% (Gr 5-10%), and ≤ 5% (Gr ≤ 5%). T cells and macrophages were evaluated in the apical myocardium after left ventricular assist device implantation.

Results: During left ventricular assist device support, 12 patients underwent heart transplantation and 2 patients died. Four patients with Gr ≤ 5% were readmitted because of congestive heart failure, but none with Gr ≥ 10%. Macrophages and T cells in the left ventricular myocardium with Gr ≥ 10% were significantly more present compared to those in other groups.

Conclusions: The distribution of immunocompetent cells in the left ventricular myocardium might predict myocardial viability of this pathology after implantation.

Keywords: Immunocompetent cells; Left ventricular assist device; Non-ischaemic dilated cardiomyopathy.

Fig. 1

Echocardiographic measurements and serum brain natriuretic peptide (BNP) before and at 6 months after left ventricular assist device (LVAD) implantation. e–h Echocardiographic measurements and BNP are shown for each group on the basis of changes in the left ventricular ejection fraction (LVEF)

Fig. 2

a Mean numbers of macrophages (± SD) are shown for each group on the basis of changes in the left ventricular ejection fraction (LVEF). b Representative immunohistochemical staining of a smaller number of macrophages in a myocardium specimen in a patient with Gr ≤ 5%. c Representative immunohistochemical staining of a greater number of macrophages in a myocardium specimen in a patient with Gr ≤ 5%. d–g Immunohistochemical staining of myocardium specimens in each patient with Gr ≥ 10%. Macrophages positive for CD68 are stained brown. Scale bar: 40 µm

Fig. 3

a Mean numbers of T cells (± SD) are shown for each group on the basis of changes in the left ventricular ejection fraction (LVEF). b Representative immunohistochemical staining of a smaller number of T cells in a myocardium specimen in a patient with Gr ≤ 5%. c Representative immunohistochemical staining of a greater number of T cells in a myocardium specimen in a patient with Gr ≤ 5%. d–g Immunohistochemical staining of myocardium specimens in each patient with Gr ≥ 10%. T cells positive for CD3 are stained brown. Scale bar: 40 µm

Fig. 4

a Correlation between the cardiomyocyte size at the time of left ventricular assist device (LVAD) implantation and the change in the left ventricular ejection fraction (LVEF) between preimplantation and at 6 months after implantation. The dotted line shows the 95% confidence interval (CI). b Representative haematoxylin–eosin (HE) staining of a myocardium specimen in the group with LVEF improvement of < 5%. Scale bar: 20 µm. c Representative HE staining of a myocardium specimen in the group with LVEF improvement of ≥ 10%. Scale bar: 20 µm. d Correlation between the collagen area fraction at the time of LVAD implantation and change in LVEF between preimplantation and at 6 months after implantation. The dotted line shows the 95% CI. e Representative Masson’s trichrome (M-T) staining of a myocardium specimen in the group with LVEF improvement of < 5%. Scale bar: 400 µm. f Representative M-T staining of a myocardium specimen in the group with LVEF improvement of ≥ 10%. Scale bar: 400 µm