The Effect of Hydrostatic Pressure on Coronary Flow and Pressure-Based Indices of Coronary Stenosis Severity.

: To assess whether hydrostatic pressure gradients caused by coronary height differences in supine versus prone positioning during invasive physiological stenosis assessment affect resting and hyperaemic pressure-based indices or coronary flow. : Twenty-three coronary stenoses were assessed in twenty-one patients with stable coronary artery disease. All patients had a stenosis of at least 50% visually defined on previous coronary angiography.

Absolute microvascular resistance by continuous thermodilution predicts microvascular dysfunction after ST-elevation myocardial infarction.

Aims: Continuous thermodilution using intracoronary saline infusion is a novel technique able to provide accurate measurements of absolute coronary blood flow and microvascular resistance (R). The aim of this study was to assess the ability of R, measured by continuous thermodilution, to predict microvascular dysfunction in patients with ST-elevation myocardial infarction.

Methods And Results: In this prospective observational study, continuous thermodilution was used to measure R in the culprit coronary artery of 32 patients with STEMI (mean age ± SD, 66 ± 10 years; 78% male) immediately post-primary percutaneous coronary intervention (PCI).

Coronary artery height differences and their effect on fractional flow reserve.

Background: Fractional flow reserve (FFR) uses pressure-based measurements to assess the severity of a coronary stenosis. Distal pressure (Pd) is often at a different vertical height to that of the proximal aortic pressure (Pa). The difference in pressure between Pd and Pa due to hydrostatic pressure, may impact FFR calculation.