Biomedical subjects
F Airoldi
Publications and source records attributed to F Airoldi.
Effects of balloon angioplasty and stent implantation on intrarenal echo-Doppler velocimetric indices.
This study was aimed at examining whether four intrarenal echo-Doppler velocimetric indices (pulsatility and resistive indices, acceleration and acceleration time) can be useful for assessing the effects of renal artery dilation obtained with either angioplasty or stent implantation. Echo-Doppler studies were performed in 63 hypertensive patients with 68 renal artery stenoses (39 atherosclerotic and 29 fibromuscular) prior to and within five days after the dilation procedures (55 angioplasties, 13 stent implantations), which resulted in an average reduction of arterial narrowing from 79% to 20%. In 24 patients, the velocimetric indices were also examined in relationship to the venoarterial differences of plasma renin activity and of angiotensin II across the stenotic kidneys. We found that after dilation the values of the four indices had returned within the normal range in all but three arteries (one false negative for resistive index and two for acceleration time). However, decrements in acceleration time was the only factor to be significantly correlated with the reduction of arterial narrowing. Moreover, postdilation values of this index were, on average, slightly but significantly higher in arteries that at follow-up developed restenosis rather than in those that remained patent. For similar reductions in arterial narrowing the absolute changes of all indices were similar in atherosclerotic and fibromuscular stenotic arteries and, in a subset of the atheromatous arteries, were also similar after angioplasty and stent implantation. No relationship was found with the changes in the venoarterial differences of plasma renin activity and angiotensin II. It appears that these intrarenal velocimetric indices and, in particular, acceleration time reliably reflect the technical success of renal artery dilation. The acceleration time index may also be valuable for predicting the restenosis of the dilated vessel. None of the indices, however, mirrors the functional consequences of removal of renal artery stenosis as expressed through the changes in transrenal gradients of the components of the renin-angiotensin system.
Bifurcational stenting.
Treatment of bifurcation lesions is a complex issue, and there is no single panacea to the variety of lesions that form this cohort. The contribution of side-branch compromise to the adverse clinical events occurring after stent implantation need not be stressed and requires an aggressive approach including balloon dilatation before and after stent deployment. Various new techniques of kissing stent placement, such as the 'T', 'V', 'Y', and the culottes technique, have been proposed in recent years to treat different anatomical situations. The angle formed by the side-branches, the severity of involvement of the ostia and the vessel size are the main factors which influence selection of the strategy. Newer generations of stents, such as the bifurcate stents, tailor-made for bifurcation lesions, are evolving, and are expected to make a positive impact on the procedural outcomes and long-term results after bifurcation stenting. The development of new strategies and stent designs has greatly improved safety and immediate outcome of bifurcational stenting, but the procedural success still needs to be matched by an equal improvement in long-term patency.
Superiority of acceleration and acceleration time over pulsatility and resistance indices as screening tests for renal artery stenosis.
OBJECTIVE: To compare the accuracy of four echo-Doppler-derived velocimetric indices (pulsatility and resistance indices, acceleration and acceleration time) in detecting renal artery stenosis in hypertensive patients. PATIENTS AND METHODS: In 73 hospitalized patients with moderate-to-severe hypertension, 18 of whom had normal renal arteries and 55 renal artery stenosis (50-95%) either atherosclerotic (30 cases, five bilateral) or fibromuscular dysplasia (25 cases, two bilateral), we measured the four velocimetric indices using the lateral abdominal approach and sampling Doppler waveforms distally to the stenosis. The diagnostic accuracy of each index was calculated using as cut-off limit the ideal threshold determined with the receiver-operating characteristic curves. RESULTS: On average all of the indices were altered significantly in arteries with stenosis of both aetiologies with respect to normal arteries, the alterations of pulsatility and resistance indices being, however, less pronounced than those of acceleration and acceleration time, particularly in atherosclerotic stenosis. With the cut-off limits of 0.93, 0.59 and 7.4 m/s2 and 60 ms, respectively, for pulsatility and resistance indices, acceleration and acceleration time, their diagnostic accuracies were 80, 73, 93 and 92%. In stenotic arteries, only the acceleration time was correlated with the degree of arterial narrowing, whereas, in normal arteries, only pulsatility and resistance indices were directly correlated with the age of patients. CONCLUSIONS: Acceleration and acceleration time are more accurate indices than pulsatility and resistance to screen for renal artery stenosis, probably because their alterations are less attenuated by the counterbalancing effects of age and of atherosclerosis.
[Fractures and pulmonary tuberculosis].
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[EMG pattern of radicular lesions as a result of a herniated disks. Review based on 80 cases].
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