December 1, 1972Open Access
Improvement in Myocardial Function and Coronary Blood Flow in Ischemic Myocardium after Mannitol
Key Result
Mannitol infusion during experimental myocardial ischemia in dogs significantly increased collateral coronary blood flow by 9.5 cc/min per 100 g LV and improved ventricular function.
Structured PICO
Does mannitol improve myocardial function and coronary blood flow during myocardial ischemia in a canine model?
P
Population
46 adult mongrel dogs undergoing experimental myocardial ischemia via left anterior descending coronary artery occlusion.
I
Intervention
Mannitol infused into the aortic roots before and during ischemia
C
Comparator
Ischemic state without mannitol (baseline comparison)
O
Outcome
Myocardial function (ventricular function curves), S-T segment elevation, total coronary blood flow, and collateral coronary blood flowsurrogate
In a canine model of myocardial ischemia, hyperosmolality induced by mannitol infusion improved myocardial function, reduced ischemic ECG changes, and increased both total and collateral coronary blood flow.
Main Result
Mean Difference: 9.5
Absolute Event Rate: 19.6% vs 10.1%
p-value: p=<0.005
Limitations
- Animal model (dogs) may not directly translate to human clinical practice
- Exact method and circumstances for clinical administration in patients remain unknown
- Unclear if inotropic properties are independent of blood flow effects in a hypoxic environment
Abstract
The purpose of this study was to evaluate the effect of hyperosmolality on the performance of, and the collateral blood flow to, ischemic myocardium. The myocardial response to mannitol, a hyperosmolar agent which remains extracellular, was evaluated in anesthetized dogs. Mannitol was infused into the aortic roots of 31 isovolumic hearts and of 15 dogs on right heart bypass, before and during ischemia. Myocardial ischemia was produced by temporary ligation of either the proximal or mid-left anterior descending coronary artery. Mannitol significantly improved the depressed ventricular function curves which occurred with left anterior descending coronary artery occlusion. Mannitol also significantly lessened the S-T segment elevation (epicardial electrocardiogram) occurring during myocardial ischemia in the isovolumic hearts and this reduction was associated with significant increases in total coronary blood flow (P < 0.005) and with increased collateral coronary blood flow to the ischemia area (P < 0.005).THUS, INCREASES IN SERUM OSMOLALITY PRODUCED BY MANNITOL RESULT IN THE FOLLOWING BENEFICIAL CHANGES DURING MYOCARDIAL ISCHEMIA: (a) improved myocardial function, (b) reduced S-T segment elevation, (c) increased total coronary blood flow, and (d) increased collateral coronary blood flow.