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Loop isolation-based uploading preconditioning to protect heart from damage: a proof-of-concept study

  • Hong Liu
  • Dong-dong Wu
  • Si-qiang Zheng
  • Zhi-hua Zeng
  • Tong Ding
  • Zhi-gang Liu
  • Xiao-cheng LiuEmail author
Original articles



Little is known on the role of indirect clamp releasing in coronary artery bypass grafting (CABG). Loop isolation-based uploading preconditioning (LiuPhD) was modified to protect the heart from damage and the question of whether this can attenuate reperfusion injury after global myocardial ischemia was examined.


A post-hoc comparative analysis was conducted of a prospective single-arm trial on the use of the LiuPhD strategy for 60 multivessel-disease patients undergoing isolated first-time elective on-pump CABG versus 1:1 propensity score-matched patients from the historical database of the same center.


A total of 120 matched patients had a median age of 62.0 (interquartile range [IQR] 55.8–69.0) years, 27 (22.5%) women, 35 (29.2%) with left main disease, and median follow-up of 18.5 (10.9–35.4) months. The LiuPhD group had shorter post-bypass times than conventional controls (10 [6–13] vs 14 [10–19] mins; p = 0.003). The LiuPhD group had similar needs in terms of composite cardiac-specific interventions (38/60 vs 44/60; p = 0.29). At follow-up of safety, the risk for composite major adverse cardiac and cerebrovascular events was similar between groups (event-free survival: 82.3% vs 73.8%; hazard ratio 1.00 [0.39, 2.54], p log-rank test = 0.99).


The LiuPhD strategy is associated with short post-bypass times, comparable risk of myocardial injury, and similar safety compared with conventional direct clamp releasing.


Coronary artery bypass grafting Coronary heart disease Ischemia-reperfusion injury Propensity score matching 

Loop-Isolations-basierte Beladungsvorbereitung zur Verhinderung von Schädigungen des Herzens: eine Proof-of-concept-Studie



Es gibt nur wenige Daten zur Bedeutung der indirekten Klemmenentfernung in der koronaren Bypassoperation („coronary artery bypass grafting“ [CABG]). Eine Loop-Isolations-basierte Beladungsvorbereitung („loop isolation-based uploading preconditioning“ [LiuPhD]) wurde modifiziert, um das Herz vor einer Schädigung zu schützen. Es wurde untersucht, ob dadurch der Reperfusionsschaden nach globaler Myokardischämie eingedämmt werden kann.


Es erfolgte eine vergleichende Post-hoc-Analyse einer prospektiven, einarmigen Studie zur Anwendung der LiuPhD-Strategie bei 60 Patienten mit Mehrgefäßerkrankung, die einer isolierten erstmaligen elektiven On-pump-CABG unterzogen wurden, gegenüber 1:1 Propensity-Score-gematchten Patienten aus der Datenbank desselben Zentrums.


Das mediane Alter der insgesamt 120 gematchten Patienten lag bei 62,0 Jahren (Interquartilsabstand [IQR] 55,8–69,0 Jahre), 27 (22,5 %) waren Frauen, 35 (29,2 %) hatten eine linke Hauptstammstenose und das mediane Follow-up betrug 18,5 Monate (10,9–35,4 Monate). Die LiuPhD-Gruppe wies eine kürzere Post-Bypass-Zeit als die konventionell behandelten Kontrollen auf (10 min [6–13 min] vs. 14 min [10–19 min]; p = 0,003). In der LiuPhD-Gruppe war die Notwendigkeit von kombinierten kardialen Interventionen vergleichbar (38/60 vs. 44/60; p = 0,29). Im Sicherheits-Follow-up war das Risiko kombinierter schwerer unerwünschter kardialer und zerebrovaskulärer Ereignisse in den beiden Gruppen ähnlich (ereignisfreies Überleben: 82,3 % vs. 73,8 %; Hazard Ratio 1,00 [0,39; 2,54], p log-Rang-Test = 0,99).


Die LiuPhD-Strategie ist im Vergleich zur konventionellen direkten Klemmenentfernung mit kürzeren Post-Bypass-Zeiten, einem vergleichbaren Risiko der Myokardschädigung und einem ähnlichen Sicherheitsniveau assoziiert.


Koronare Bypassoperation Koronare Herzkrankheit Ischämie-Reperfusions-Schaden Propensity-Score-Matching 



The study was supported by Fundamental Research Funds for the Central Universities (No.3332018189) and National Clinical Key Specialty Construction Projects of China.

Compliance with ethical guidelines

Conflict of interest

H. Liu, D.-d. Wu, S.-q. Zheng, Z.-h. Zeng, T. Ding, Z.-g. Liu and X.-c. Liu declare that they have no competing interests.

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1975 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent was obtained from all individual participants included in the study.


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Copyright information

© Springer Medizin Verlag GmbH, ein Teil von Springer Nature 2019

Authors and Affiliations

  1. 1.Department of Cardiovascular Surgery, TEDA International Cardiovascular HospitalChinese Academy of Medical Sciences & Peking Union Medical CollegeTianjinChina

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