# Histological Evaluation for Collagen Expression Prior to LVAD Implantation Is Useful to Estimate Weaning Success

## TL;DR

This study shows that analyzing collagen in heart tissue before implanting a heart pump can help predict if a patient will recover well enough to stop using the pump.

## Contribution

The study demonstrates that collagen I and III histological evaluation before LVAD implantation can estimate weaning success.

## Key findings

- Histological collagen I and III levels were lower in non-recovering patients compared to recovering patients.
- Collagen mRNA levels did not differ significantly between groups.
- Immunohistochemistry revealed significant differences in collagen I and III between groups.

## Abstract

Introduction: The implantation of a left ventricular assist device (LVAD) is a life-saving therapeutic option for patients with advanced heart failure. The treatment goal has to be determined prior to LVAD implantation. However, prognostic evaluation for defining the treatment goal could be improved for a time- and cost-effective medical treatment. Methods: Our study comprised seven patients who were weaned from LVAD (recovery group) and a control group without weaning (non-recovery group; n = 7). Myocardial tissue was analysed for connective tissue content by Masson–Goldner trichrome staining and for collagen I and collagen III expression by quantitative real-time PCR and immunohistochemistry. Results: The histological evaluation revealed comparable values for the percentage of total connective tissue (non-recovery: 46.3% [95% CI: 15.9–76.7], recovery: 43.4% [95% CI: 13.7–73.2], p = 0.43). mRNA expression analysis for collagen I and III expression could not detect a difference in collagen I (p = 0.16) and collagen III expression (p = 0.12) between the non-recovery and the recovery group. Immunohistochemical staining revealed that the percentages of collagen I (p = 0.05) and of collagen III (p = 0.01) were reduced in patients who do not recover compared to patients who recover under LVAD support. Conclusions: Our data indicate that histological evaluation for collagen expression prior to LVAD implantation could detect differences in the collagen content that could be helpful for estimating the weaning success.