Biomedical subjects

Emanuele Barbato

Publications and source records attributed to Emanuele Barbato.

3 recordsLinked to original sources

PubMed2003

Intracoronary and intravenous adenosine 5'-triphosphate, adenosine, papaverine, and contrast medium to assess fractional flow reserve in humans.

BACKGROUND: Inducing both maximal and steady-state coronary hyperemia is of clinical importance to take full advantage of fractional flow reserve measurements. The present study compares different dosages and routes of administration of adenosine 5'-triphosphate (ATP), adenosine, contrast medium, and papaverine regarding their potential to achieve both maximal and steady-state hyperemia. METHODS AND RESULTS: In 21 patients with an isolated coronary stenosis, coronary vasodilation was induced successively by papaverine (20 mg intracoronary), adenosine (20 and 40 microg intracoronary), ATP (20 and 40 microg intracoronary), iohexol (6 mL intracoronary), adenosine or ATP through an antecubital vein (140 and 180 microg x kg(-1) x min(-1)), or adenosine or ATP through a femoral vein (140 and 180 microg x kg(-1) x min(-1)). Because vessel dimensions did not change, the ratio of distal coronary pressure (Pd) to aortic pressure (Pa) was used as an index of myocardial resistance. Pd/Pa was 0.77+/-0.21 at rest and decreased to 0.61+/-0.21 after papaverine. Pd/Pa decreased to a similar level with all other vasodilators, except with contrast medium (0.68+/-0.21; P<0.01 versus papaverine). Steady-state hyperemia could only be obtained by intracoronary papaverine and by intravenous ATP or adenosine. In another 23 patients, an intravenous infusion of ATP was varied from 0 to 280 microg x kg(-1) x min(-1). At doses >140 microg x kg(-1) x min(-1), there was neither a further decrease in Pd/Pa ratio nor a further increase in coronary flow velocities. CONCLUSIONS: Provided sufficient dosages are used, ATP, adenosine, and papaverine (but not contrast medium) induce maximal hyperemia and are therefore suitable to assess fractional flow reserve. Only intracoronary papaverine and intravenous ATP or adenosine induce steady-state hyperemia enabling a pressure pullback maneuver that is useful in assessing diffuse coronary atherosclerosis.

Adenosine↗

PubMed2003

Direct stenting.

Stents have ameliorated the outcome of percutaneous coronary interventions. Improved design, profile and flexibility of the currently available stents now permit to deliver the stent without pre-dilatation. In western European countries, stent implantation now occurs in up to 80% of all percutaneous revascularization procedures. In selected cases the safety and feasibility of direct stenting over conventional balloon-predilatation stenting has been demonstrated, in association with slightly superior outcome. This likely results from reduced vessel wall damage-dissections are sealed at the moment they are created-and distal embolization is reduced. In addition, a significant reduction in terms of costs and duration of procedures was demonstrated, while restenosis rate is not reduced with direct stenting.

Angioplasty, Balloon, Coronary↗

PubMed2002

Coronary thermodilution to assess flow reserve: validation in humans.

BACKGROUND: Guide wire-based simultaneous measurement of fractional flow reserve (FFR) and coronary flow reserve (CFR) is important to understand microvascular disease of the heart. The aim of this study was to investigate the feasibility of simultaneous measurement of FFR and CFR by one pressure-temperature sensor-tipped guide wire with the use of coronary thermodilution and to compare CFR by thermodilution (CFR(thermo)) with simultaneously measured Doppler CFR (CFR(Doppl)). METHODS AND RESULTS: In 103 coronary arteries in 50 patients, a pressure-temperature sensor-tipped 0.014-inch floppy guide wire and a 0.014-inch Doppler guide wire were introduced. Both normal vessels and a wide range of stenotic vessels were included. With 3 mL of saline at room temperature used as an indicator, by hand-injection, thermodilution curves in the coronary artery were obtained in triplicate, both at baseline and at intravenous adenosine-induced maximum hyperemia. After adequate curve-fitting, CFR(thermo) was calculated from the ratio of inverse mean transit times and compared with CFR(Doppl) calculated by velocities at hyperemia and baseline. Adequate sets of thermodilution curves and corresponding CFR(thermo) could be obtained in 87% of the arteries versus 91% for Doppler CFR and 100% for FFR. CFR(thermo) correlated fairly well to CFR(Doppl) (CFR(thermo)=0.84 CFR(Doppl)+0.17; r=0.80; P<0.001), although individual differences of >20% between both indexes were seen in a quarter of all arteries. CONCLUSIONS: This study shows the feasibility of simultaneous measurement of FFR (by coronary pressure) and CFR (by coronary thermodilution) in humans by one single guide wire in a practical and straightforward way and will facilitate assessment of microvascular disease.

Blood Flow Velocity↗