What question did this study set out to answer?

To determine whether repetitive brief periods of coronary occlusion separated by reperfusion cause cumulative myocardial adenine nucleotide depletion, lactate accumulation, or necrosis.

December 1, 1986AJP Heart and Circulatory Physiology

Four brief periods of myocardial ischemia cause no cumulative ATP loss or necrosis

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Why the study?

Does intermittent coronary occlusion with reperfusion prevent cumulative metabolic deficits and necrosis compared to continuous occlusion in a canine model?

Key Points

To determine whether repetitive brief periods of coronary occlusion separated by reperfusion cause cumulative myocardial adenine nucleotide depletion, lactate accumulation, or necrosis.
Occluded the circumflex artery in canine models for one, two, or four 10-minute episodes separated by 20 minutes of reperfusion, compared to 40 minutes of continuous coronary occlusion.
Sampled excised hearts for subendocardial ATP, adenine nucleotides, and lactate, while monitoring collateral blood flow.
Quantitated myocardial necrosis 4 days following four 10-minute ischemic episodes in a second cohort (N=6).
A single 10-minute ischemic episode caused a 61% loss of ATP and a 41% loss of adenine nucleotides, but subsequent two or four episodes caused no further nucleotide loss, compared to an 87% ATP and 67% nucleotide depletion after 40 minutes of continuous occlusion.
Lactate accumulation was reduced during later occlusive episodes despite similar collateral blood flow across all occlusions.
Myocardial necrosis occurred in only 1 of 6 dogs after four 10-minute ischemic periods, accounting for just 1.5% of the anatomic area at risk.

Structured PICO

Does intermittent coronary occlusion with reperfusion prevent cumulative metabolic deficits and necrosis compared to continuous occlusion in a canine model?

Population

Canine model (dogs) subjected to circumflex artery occlusion (at least n=6 in the necrosis series)

Intervention

Intermittent circumflex artery occlusion (one, two, or four 10-minute episodes, each separated by 20 minutes of reperfusion)

Comparator

40 minutes of continuous coronary occlusion

Outcome

Myocardial adenine nucleotides, lactate, and infarct size (necrosis)surrogate

Brief, repetitive periods of myocardial ischemia do not cause cumulative ATP loss or significant necrosis, demonstrating the protective metabolic effect of intermittent reperfusion.

Discussion

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Implication

Intermittent ischemia with reperfusion may limit ATP depletion and necrosis in canine myocardium; hypothesis-generating for human cardioprotection.

Cite This Study

Reimer et al. (1986) studied this question.

synapsesocial.com/papers/6a0f08471c5e2d2319fa4178 https://doi.org/10.1152/ajpheart.1986.251.6.h1306

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Implication

Intermittent ischemia with reperfusion may limit ATP depletion and necrosis in canine myocardium; hypothesis-generating for human cardioprotection.

Four brief periods of myocardial ischemia cause no cumulative ATP loss or necrosis

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Four brief periods of myocardial ischemia cause no cumulative ATP loss or necrosis

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Also Consider

Also Consider