Determination of Optimal Perfusion Pressure for Normothermic Ex-Situ Donor Heart Preservation in a Rat Model

10129 

Abstract Submission 

Inseok Jeong (1), Ho Seong Cho (2), Mukhammad Kayumov (3), Hwa-Jin Cho (4), Do Wan Kim (1), Gyo Seon Lee (1), Seunghwan Song (5), Yang Hyun Cho (6)

(1) Chonnam National University Hospital and Medical School, Gwangju, Republic of Korea, (2) Pusan National University Hospital and School of Medicine, Biomedical Research Institute, Busan, Republic of Korea, (3) Brigham and Women's Hospital, Harvard Medical School, Boston, MA, (4) Chonnam National University Children’s Hospital and Medical School, Gwangju, Republic of Korea, (5) Pusan National University Hospital and School of Medicine, Busan, Republic of Korea, (6) Samsung Medical Center, Sungkyunkwan University, Seoul, Republic of Korea

Inseok Jeong    -  Contact Me
Chonnam National University Hospital and Medical School

Ho Seong Cho    -  Contact Me
Pusan National University Hospital and School of Medicine, Biomedical Research Institute

Mukhammad Kayumov    -  Contact Me
Brigham and Women's Hospital, Harvard Medical School

Hwa-Jin Cho    -  Contact Me
Chonnam National University Children’s Hospital and Medical School

Do Wan Kim    -  Contact Me
Chonnam National University Hospital and Medical School

Gyo Seon Lee    -  Contact Me
Chonnam National University Hospital and Medical School

Seunghwan Song    -  Contact Me
Pusan National University Hospital and School of Medicine

Yang Hyun Cho    -  Contact Me
Samsung Medical Center, Sungkyunkwan University

Ho Seong Cho    -  Contact Me
Pusan National University Hospital

Objective
Normothermic ex-situ heart preservation extends the viability of donor hearts by maintaining physiological temperatures and reducing ischemic damage. However, the optimal perfusion pressure remains unknown. This study aims to determine the best perfusion pressure in a rat model to improve heart preservation and expand the donor pool.

Materials
Twenty male Sprague-Dawley rats (400-500g) were used in this study. Donor hearts were subjected to normothermic preservation (NP) for 2 hours using a 12ml Langendorff priming circuit with a 2-3 ml/min perfusion rate. After 2 hours, hearts were harvested with HTK solution and weighed before and after ex-situ perfusion. Post-preservation, hearts underwent heterotopic abdominal transplantation. ECG recordings for 3 hours post-transplantation determined the success of preservation, with the presence of the QRS complex indicating success. Statistical analysis compared outcomes between the successful and unsuccessful groups. Histological analysis was performed after 4 hours of reperfusion to assess heart tissue.

Results
In ECG monitoring, 8 out of 20 donor hearts showed the absence of the QRS complex, indicating unsuccessful NP preservation. Ischemic times were not significantly different between the two groups. At 120 minutes, serum lactate and potassium levels increased more in the unsuccessful group, although this was not statistically significant. Higher initial perfusion pressure (>65 mmHg) was associated with elevated lactate and potassium levels after 2 hours of NP preservation, indicating worse outcomes. Successfully preserved hearts maintained better structure in HE staining, while TUNEL staining revealed more DNA strand breaks in unsuccessfully preserved hearts. Heart weight increased significantly post-NP preservation, but this increase was statistically significant only in the unsuccessful group.

Conclusions
Higher initial perfusion pressures (>65 mmHg) were associated with worse outcomes, including elevated serum lactate and potassium levels, increased heart weight, and more significant DNA damage. These findings suggest that maintaining an optimal perfusion pressure is crucial for preserving heart structure and function.

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