Four studies with six study arms were included in the review. Each study arm had a paired before and after design (n=66, range six to 16 in each arm).
In all study arms there was a statistically significant reduction in coronary blood flow associated with the intervention (mean change -7.9% to -28.9%, p<0.05), with no statistically significant change in the diameter of the large conduit coronary arteries.
Four study arms measured coronary vascular resistance. In all cases there was a statistically significant increase associated with the intervention (mean change 21.5% to 40.9%, p<0.01 where reported).
Three study arms measured myocardial oxygen consumption. In all cases there was a statistically significant reduction associated with the intervention (mean change -15.3% to -26.9%, p<0.05).
The review also reported: lactate concentration; left ventricular haemodynamics, contractility and relaxation; and oxidant mechanisms.