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

Abstract

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.

• Authors: Paul F Klawitter, Holt N Murray, Thomas L Clanton, Brian S Palmer, Mark G Angelos
• Journal: Critical care medicine (Crit Care Med) Vol. 30 Issue 11 Pg. 2542-7 (Nov 2002) ISSN: 0090-3493 [Print] United States
• PMID: 12441767 (Publication Type: Evaluation Study, Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Topics

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