What is the clinical evidence from this study?

Study design: Other. Population: Myocardial ischemia (n=46). Intervention: Mannitol vs. Ischemia without mannitol (control ischemic periods). Primary outcome: Collateral coronary blood flow during ischemia (MD 9.5 cc/min per 100 g LV, p=<0.005).

December 1, 1972Journal of Clinical Investigation189 citationsOpen Access

Improvement in Myocardial Function and Coronary Blood Flow in Ischemic Myocardium after Mannitol

Q: What are the key findings of this study?

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.

JWJames T. Willerson WPW J Powell TGTimothy E. Guiney

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?

Population

46 adult mongrel dogs undergoing experimental myocardial ischemia via left anterior descending coronary artery occlusion.

Intervention

Mannitol infused into the aortic roots before and during ischemia

Comparator

Ischemic state without mannitol (baseline comparison)

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.

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