SOURCES OF ERROR IN INTRAARTERIAL PRESSURE MEASUREMENTS ACROSS A STENOSIS

Objective: To investigate potential errors associated with different t echniques of intra-arterial pressure measurement at angiography. Mater ials and methods: An experimental model of an arterial stenosis was de veloped. Experiments were performed to assess the relevance of cathete r position, catheter direction and catheter type on the recorded intra luminal pressure. Transstenotic pressure gradients were recorded with and without angiographic catheters crossing the stenosis. Results: At physiological flow rates angiographic catheter type does not influence the recorded pressure. At high flow rates through tight stenoses ther e is a significant catheter-related difference in recorded pressure ad jacent to a stenosis. Downstream pressures may be altered by up to 85 mmHg when standard angiographic catheters are placed across a stenosis . Conclusion: The different techniques employed to measure pressure di fferences across a model stenosis may introduce significant errors tip to 85 mmHg. Care must be taken when pressure measurements alone are u sed to interpret the clinical significance of a stenosis. In low flow conditions there may not be a detectable pressure gradient across a 95 % stenosis.