Decreased carotid and vertebral arterial blood-flow velocity in response to orthostatic unload in patients with severe aortic stenosis

Background: Responses of cerebral blood flow to the postural unloading maneuver in aortic stenosis (AS) have not been described so far. Our aim was to assess effects of orthostatic stress test on changes of carotid and vertebral artery blood flow and transaortic gradients. Methods: From consecutive 101 AS patients we selected 50 patients with severe isolated AS. Maximal and mean transaortic pressure gradients, as well as peak systolic blood-flow velocity (PSV) and end-diastolic velocity (EDV) in the common carotid artery, internal carotid artery and vertebral artery on both sides were measured by duplex ultrasound in the supine position and at 1–2 min after the assumption of the sitting position in patients with AS, and in stand­ing position in healthy controls. Results: The orthostatic stress test induced significant decrease of carotid and vertebral arterial flow velocities in AS patients. Transaortic pressure gradients also dropped while the patients were sitting (p < 0.001). A history of syncope/presyncope was not associated with a significantly lower PSV and EDV in carotid and vertebral arteries in the upright position. In healthy controls, the velocities in carotid and vertebral arterial flow have been unchanged after maneuver reducing preload. Conclusions: In AS patients, decrease of carotid and vertebral arterial flow velocities and transaortic gradients in the sitting position were observed. Orthostatic test position does not ap­pear to be associated with a history of syncope/presyncope in patients with severe isolated AS, de­spite a simultaneous drop of transvalvular pressure gradient

Comparison of hyperemic efficacy between femoral and antecubital fossa vein adenosine infusion for fractional flow reserve assessment

Introduction: Intravenous infusion of adenosine via the femoral vein is commonly used to achieve maximum hyperemia for fractional flow reserve (FFR) assessment in the catheterization laboratory. In the era of transradial access for coronary interventions, obtaining additional venous access with sheath insertion in the groin is unpractical and may be associated with a higher risk of bleeding complications. In a vast majority of cases, patients scheduled for the catheterization laboratory are already equipped with peripheral vein access in antecubital fossa vein. However, only limited data exist to support non-central vein infusion of adenosine instead of the femoral vein for FFR assessment. Aim: To compare infusion of adenosine via a central versus a peripheral vein for the assessment of peak FFR. Material and methods: We enrolled 50 consecutive patients with 125 borderline coronary lesions that were assessed by FFR using adenosine femoral and antecubital vein infusion of 140 μg/kg/min. Results: Physiological severity assessed with femoral vein adenosine infusion at 140 μg/kg/min was mean 0.82 ±0.09, and with antecubital vein adenosine infusion at 140 μg/kg/min was 0.82 ±0.09. The mean time from initiation of adenosine infusion to maximal stable hyperemia was significantly shorter for 140 μg/kg/min femoral vein infusion as compared to antecubital vein infusion (49 ±19 s vs. 68 ±23 s; p < 0.001). There was a strong correlation between FFR values obtained from 140 μg/kg/min femoral and antecubital vein infusion (r = 0.99; p < 0.001). Conclusions: Antecubital vein adenosine infusion achieved FFR values are very similar to those obtained using femoral vein adenosine administration. However, time to maximal hyperemia is longer with infusion via the antecubital vein

Adenosine intracoronary bolus dose escalation versus intravenous infusion to induce maximum coronary hyperemia for fractional flow reserve assessment

Background: Achievement of maximal hyperemia is mandatory for an accurate calculation of fractional flow reserve (FFR) and it is obtained with adenosine given either as an intravenous infusion or as an intracoronary bolus. Aims: The purpose of this study was to compare the infusion of adenosine with intracoronary adenosine bolus dose escalation in the optimal assessment of peak FFR. Methods: We enrolled consecutive patients with borderline coronary lesions that were assessed by FFR with the use of adenosine intracoronary boluses (100, 200, 400 and 600 µg) and intravenous infusion of 140 µg/kg/min and 280 µg/kg/min. FFR values were assessed and compared. Results: Fifty patients with 125 borderline coronary artery stenoses were enrolled. Physiological severity assessed with: intravenous adenosine infusion at 140 µg/kg/min was mean 0.82 ± 0.09; infusion at 280 µg/kg/min – 0.81 ± 0.09; intracoronary bolus of 100 µg, 200 µg, 400 µg and 600 µg – 0.83 ± 0.09; 0.83 ± 0.09, 0.83 ± 0.09; and 0.83 ± 0.09, respectively. There was a strong linear correlation between FFR values obtained from 140 µg/kg/min infusion and adenosine intracoronary 100, 200, 400 and 600 µg bolus injection (r = 0.989, r = 0.99, r = 0.993, r = 0.994, respectively, p &lt; 0.001 for all). Conclusions: FFR values achieved with intracoronary boluses of adenosine are very similar, but not identical to those obtained using intravenous adenosine administration. The values of FFR may vary between escalating doses of intracoronary boluses and intravenous infusion

Predictors of syncope in patients with severe aortic stenosis: The role of orthostatic unload test

Background: There is a paucity of data regarding response of cerebral blood flow to the postural unloading maneuver and its impact on the risk of syncope in patients with aortic stenosis (AS). The aim of the present study was to assess effects of orthostatic stress test on changes in carotid and vertebral artery blood flow and its association with syncope in patients with severe AS.Methods: 108 patients were enrolled (72 with and 36 patients without syncope) with severe isolated severe AS. Peak systolic blood-flow velocity (PSV) and end-diastolic velocity in the carotid arteries and vertebral arteries were measured by duplex ultrasound in the supine position and at 1–2 min after the assumption of the standing position.Results: The orthostatic stress test induced a significant decrease in carotid and vertebral arterial flow velocities in all examined arteries (p &lt; 0.001). The median (interquartile range) of mean change in PSV for carotid arteries was higher for patients with syncope (syncope [–] vs. syncope [+]: –0.6 cm/s [–1.8, 1.0] vs. –7.3 cm/s [–9.5, –2.0]; p &lt; 0.001) and similarly for vertebral arteries (–0.5 cm/s [–2.0, 0.5] vs. –4.8 cm/s [–6.5, –1.3]; p &lt; 0.001, respectively). Age, aortic valve area, and mean change in PSV for carotid arteries were independently associated with syncope.Conclusions: In patients with AS, a decrease in carotid and vertebral arterial flow velocities in the standing position was observed and was associated with syncope. The present findings may support the value of an orthostatic test in identifying patients with severe AS and a high risk of syncope