Low flow after global ischemia to improve postischemic myocardial function and bioenergetics

Crit Care Med. 2002 Nov;30(11):2542-7. doi: 10.1097/00003246-200211000-00023.


Objective: In this study, we test the hypothesis that a period of low flow perfusion before full reperfusion improves ventricular function and bioenergetics.

Design: Prospective, randomized, controlled animal study.

Setting: Research laboratory.

Subjects: Sprague-Dawley rats.

Interventions: Hearts were perfused with Krebs-Henseleit buffer at 85 mm Hg. The protocol consisted of 10 mins of baseline flow, 15 mins of global ischemia, 5 mins of low flow ischemia, and 30 mins of reperfusion. Groups received 10% or 1% of baseline flow during the low flow period. A control group received 0% low flow (20 mins of global ischemia).

Measurements and main results: Left ventricular function was continuously measured. Hearts were freeze-clamped at various time points, and metabolites were measured. At 10% flow, following global ischemia, both left ventricular function and bioenergetics improved compared with 0% flow and 1% flow. At 1% flow, no changes in function were seen and adenosine 5'-triphosphate concentrations decreased during reperfusion, compared with no flow (9.4 +/- 1.0 vs. 13.2 +/- 1.0 micromol/g of dry weight, p <.01).

Conclusions: Following global ischemia but before full reperfusion, a period of low flow improves postischemic myocardial function and energetic recovery, only if a certain level of low flow is met. Very low flow may further reduce bioenergetic recovery without improvement in postischemic function, compared with continuous global ischemia.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Analysis of Variance
  • Animals
  • Cardiopulmonary Resuscitation*
  • Energy Metabolism*
  • Heart Arrest / physiopathology
  • Heart Arrest / therapy*
  • Male
  • Myocardial Reperfusion / methods*
  • Myocardial Stunning / physiopathology
  • Prospective Studies
  • Random Allocation
  • Rats
  • Rats, Sprague-Dawley
  • Time Factors
  • Ventricular Function, Left*