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Biomedical subjects

A Colombo

Publications and source records attributed to A Colombo.

At least 19 recordsLinked to original sources
PubMed2002

Angiographical follow-up after radioactive "Cold Ends" stent implantation: a multicenter trial.

BACKGROUND: Radioactive stents with an activity of 0.75 to 12 microCi have shown >40% edge restenosis due to neointimal hyperplasia and negative remodeling. This trial evaluated whether radioactive Cold Ends stents might resolve edge restenosis by preventing remodeling at the injured extremities. METHODS AND RESULTS: The 25-mm long (15-mm radioactive center and 5-mm nonradioactive ends) Cold Ends stents had an activity of 3 to 12 microCi at implantation. Forty-three stents were implanted in 43 patients with de novo native coronary artery disease. Two procedural, 1 subacute, and 1 late stent thrombosis occurred. A restenosis rate of 22% was observed with a shift of the restenosis, usually occurring at the stent edges of radioactive stents, into the Cold Ends stents. The most severe restenosis occurred at the transition zone from radioactive to nonradioactive segments, a region located in dose fall-off. CONCLUSION: Cold Ends stents did not resolve edge restenosis.

Adult↗
PubMed2002

Cerebral veno-arterial pCO2 difference as an estimator of uncompensated cerebral hypoperfusion.

The aim of the present study was to assess the veno-arterial difference in pCO2 (delta pCO2) as an indicator of ischemia compared to the arteriovenous O2 difference (AVDO2). Staircase cerebral blood flow (CBF) reductions were obtained in seven domestic pigs by inducing intracranial hypertension: CBF 100%, 50-60% of baseline, 20-30% of baseline. ICP, MAP, CPP and CBF (Laser-Doppler method) were continuously recorded. The superior sagittal sinus was punctured to determine AVDO2 and delta pCO2. AVDO2 was 5.9 (+/- 1.78, range 3.3-7.4), 7.01 (+/- 1.31, range 5-8.9) and 8.17 (+/- 1.51, range 6.0-11.3) ml/100 ml in the three CBF steps (p = 0.001). CBF impairment was accompanied by the following increases in delta pCO2: from 10 (+/- 4, range 4-15) mmHg to 14.5 (+/- 4.11, range 10-27) mmHg, and to 31.2 (+/- 9.0, range 17-39) mmHg (p < 0.001). When CBF declines AVDO2 increases, indicating greater extraction of O2 to satisfy the aerobic metabolism. However, this mechanism can no longer compensate once a critical CBF threshold is reached. delta pCO2 rises slowly during moderate CBF reduction because of defective washout; the rise is impressive during marked CBF impairment when anaerobic metabolism takes place with proton buffering in CO2 and H2O. Therefore, when the brain's ability to compensate for low blood flow is exceeded, CO2 production outweighs O2 extraction.

Animals↗
PubMed2002

Discrepancy between angiography and intravascular ultrasound when analysing small coronary arteries.

AIMS: A small reference diameter may be the consequence of high plaque burden and diffuse disease. The reference vessel diameter in small coronary arteries may vary according to the method of measurement used. We endeavoured to confirm the difference between data from examinations conducted using angiography with that revealed by intravascular ultrasound. METHODS AND RESULTS: Between March 1993 and October 1999, 344 consecutive patients with 419 lesions in small vessels (< or =2.75 mm, Small group) and 953 patients with 1161 lesions in large vessels (Large group) underwent intravascular ultrasound-guided percutaneous transluminal angioplasty in our Institution. The mean difference between the intravascular ultrasound and the angiographic reference diameter (Delta(IVUS-Angio)) was 1.3+/-0.5 mm in the Small group and 1.0+/-0.6 mm in the Large group (P<0.001). There was a stronger correlation between plaque burden and Delta(IVUS-Angio)in the Small group (r=0.80, P<0.001) than in the Large group (r=0.59, P<0.001). An Delta(IVUS-Angio)> or =0.30 mm occurred in 99.5% of cases in the Small group and in 90% in the Large group (P<0.001). An Delta(IVUS-Angio)> or =0.50 mm occurred in 96% of case in the Small group and 80% in the Large group (P<0.001). Predictors of Delta(IVUS-Angio)> or =0.50 in the Small group were: proximal or middle lesion site, vessel type (left anterior descending artery, diagonal and obtuse marginal branches) and female sex. An Delta(IVUS-Angio)> or =1.0 mm occurred in 71% of cases in the Small group and in 49% in the Large group (P<0.001). Predictors of Delta(IVUS-Angio)> or =1.0 mm in the Small group were: proximal or middle lesion site, female sex, and lesion length. CONCLUSIONS: A high percentage of vessels measuring < or =2.75 mm are large vessels with a high plaque burden. This condition is particularly prevalent in females, with lesions in the proximal or middle left anterior descending artery, and in obtuse marginal and diagonal branches.

Aged↗
PubMed2002

Impact of final coronary flow velocity reserve on late outcome following stent implantation.

Aims To assess whether coronary flow velocity reserve following stent implantation is predictive of the subsequent need of target lesion revascularization. Methods and Results The outcome was examined of 417 patients enrolled in a multicentre prospective randomized study (DESTINI), who received a successful single vessel stent implantation in native coronary arteries and in whom coronary flow velocity reserve was measured. Logistic regression analysis and the receiver operator characteristic curve were used. When compared with 358 patients not requiring target lesion revascularization, 59 patients (14%) who underwent target lesion revascularization had a lower final coronary flow velocity reserve (2.33 +/- 0.87 vs 2.48+/- 0.80, P= 0.20) and smaller final minimal lumen diameter (2.62 +/- 0.66 mm vs 2.73+/- 0.60, P= 0.19); however, those differences were not statistically significant. Patients with a coronary flow velocity reserve of < 2.0 (n=109, 26%) exhibited a significantly higher target lesion revascularization rate than patients with a coronary flow velocity reserve of > or = 2.0 (22% vs 11%, P= 0.010). This difference remained significant (odds ratio=2.01, 95% CI=1.11 to 3.66) after adjustment for other variables that were also correlated with the incidence of target lesion revascularization. Conclusion The presence of a final coronary flow velocity reserve of < 2.0 is an independent predictor of the need for target lesion revascularization after stent implantation in native coronary artery lesions.

Blood Flow Velocity↗
PubMed2002

Production of anti-endomysial antibodies in cultured duodenal mucosa: usefulness in coeliac disease diagnosis.

BACKGROUND: Although anti-endomysial antibodies (EmA) have been found in the supernatants of cultured intestinal mucosa from patients with coeliac disease (CD), in no study has the clinical reliability of this new diagnostic tool been investigated. Our aims were to evaluate the clinical usefulness of the in vitro production of EmA in CD diagnosis in consecutive patients with suspected CD, and to evaluate the reliability of the in vitro challenge in CD patients on a gluten-free diet (GFD). METHODS: For the former aim, consecutive patients who were due to undergo intestinal biopsy for suspected diagnosis of CD were enrolled: according to the final diagnosis, these patients were divided into two groups: Group 1 comprised 91 newly diagnosed CD patients (40 males; age range 7 months to 84 years), Group 2 included 100 subjects with diseases other than CD (44 males; age range 9 months to 76 years). For the latter aim, we also studied 21 CD patients on a gluten-free diet after 16-123 months (8 males; age range 3-51 years), with normal intestinal architecture (Group 3) and 22 patients who served as controls (12 males; age range 4-60 years) with gastroesophageal reflux disease-like symptoms (Group 4). All patients underwent determination of serum anti-gliadin (AGA) and EmA antibodies, histology evaluation of the intestinal biopsies and EmA assay in the supernatants of in vitro gliadin-challenged duodenal mucosa. RESULTS: EmA assay in the supernatants showed a sensitivity and specificity of 96% and 100%, respectively; these were not significantly different from those observed for serum EmA (88% and 99%, respectively). However, EmA assay in the supernatants was useful in CD patients with mild intestinal histology lesions (infiltrative/hyperplastic type): in this subgroup it was positive in 9/12 of cases, but serum EmA was positive in only 2/12. As regards the reliability of the in vitro gliadin challenge, EmA production in supernatants was recorded only in 10/21 CD patients on a gluten-free diet. The patients with a positive in vitro challenge had a higher number of intra-epithelial lymphocytes than patients with a negative challenge. CONCLUSIONS: 1) EmA assay in the medium of cultured intestinal biopsy can detect gluten-sensitive enteropathy, characterized by an infiltrative/hyperplastic histological pattern, which is often associated with negative serum EmA. 2) The in vitro challenge in CD patients on a gluten-free diet detects EmA production in the culture medium only in half of the cases and other studies must be performed to evaluate whether EmA production after in vitro challenge can be considered a reliable test for confirming CD diagnosis.

Adolescent↗
PubMed2002

Carotid artery stenting in the first 100 consecutive patients: results and follow up.

BACKGROUND: Carotid artery stenting is now used as an alternative to surgical endarterectomy. The availability of cerebral protection systems has expanded the area of application of this procedure. OBJECTIVE: To assess the feasibility, safety, and immediate and late clinical outcome in patients undergoing percutaneous carotid interventions. METHODS: Between January 1999 and December 2000, 100 consecutive patients with 102 carotid artery stenoses were treated (71 men, 29 women, mean (SD) age 67 (8) years): 49 had coronary artery disease, 28 had previous stroke or transient ischaemic attack (TIA). On the basis of the Mayo Clinic carotid endarterectomy risk scale, 73 patients were grade III-IV and 13 grade VI. RESULTS: Baseline diameter stenosis was 78.8 (10)%, with a mean lesion length of 12.6 (5.8) mm. Angiographic success was obtained in 99 lesions (97.0%) with a final diameter stenosis of 2.4 (3.5)%. Procedural success was obtained in 96 patients (96%). Selective cannulation of three carotid arteries was impossible owing to severe vessel tortuosity. Carotid stenting was performed in 97 of the treated lesions, and protection devices were used in 67 lesions. In-hospital complications occurred in seven patients (six TIA, one (category 1) minor stroke). No major stroke or death occurred. All patients were discharged from the hospital after an average of 2.5 days. At 12 (6.2) months of follow up restenosis occurred in three patients (3.4%) (one patient with carotid occlusion had TIA). Six patients had died: two from cerebrovascular events (5 and 11 months after the procedure) and four from cardiovascular causes. CONCLUSIONS: Carotid stenting appears feasible and safe, with few major complications. Long term follow up is affected by a high incidence of cardiovascular mortality.

Adult↗
PubMed2002

Drug-eluting stents.

Drug-eluting stents represent the third revolution in the field of Interventional Cardiology following balloon angioplasty (PTCA) and the implantation of metal stents. The main limitation of percutaneous coronary intervention (PCI) is restenosis. The introduction of drug eluting stents able to release antiproliferative compounds led to the evaluation of several antiproliferative drugs in order to reduce restenosis. Rapamycin (Sirolimus) has been demonstrated to inhibit smooth muscle cell (SMC) proliferation and migration in vitro and to reduce in vivo neointima formation with blockage of the cell cycle progression at the G1-S transition. In a pilot study, recently confirmed by a randomized trial, rapamycin drug-eluting stents have been reported to eliminate restenosis after stent implantation. Promising data also come from the use of paclitaxel drug-eluting stents. Paclitaxel (Taxol) is a microtubule-stabilizing agent with potent antiproliferative activity. Even if drug-eluting stents represent one of the most promising fields in Interventional Cardiology today before being sure of their real potential it is necessary to wait for results from several ongoing clinical studies, their usage in real-world lesions and extended follow-up to 5 years.

Angioplasty, Balloon, Coronary↗
PubMed2001

Immediate and long-term clinical and angiographic results from Wiktor stent treatment for true bifurcation narrowings.

From January 1996 to December 1998, 90 consecutive patients with true bifurcation lesions underwent percutaneous coronary angioplasty with Wiktor stent implantation in our centers. In 1 group (group I, n = 45), a simple approach (main vessel stenting and balloon angioplasty of the side branch) was pursued. In the other group (group II, n = 45), both the main vessel and the side branch were stented ("T" technique). There was no significant difference in clinical and angiographic characteristics between the 2 groups. Angiographic and procedural successes were 100% and 95.6%, respectively, in both groups. Angiographic results for the side branch were better in group II than in group I. In-hospital and long-term (12 month) major cardiac events were similar in the 2 groups. Target lesion revascularization was 15.5% in group I and 35.5% in group II (p = 0.12). In the main vessel, restenosis rate was 12.5% in group I and 25% in group II (p = 0.15). In the side branch, restenosis rate was 37.5% in group II and 12.5% in group I (p = <0.05; odds ratio 2.42; 95% confidence interval 1.05 to 6.26). Event-free probability at 12 months was 61% in group II and 80% in group I (p = 0.10). When dealing with true bifurcation lesions, a simple strategy is associated with a lower risk of restenosis in the side branch. In contrast, a complex approach does not appear to give any benefit in terms of early or long-term outcome or restenosis rate.

Angioplasty, Balloon, Coronary↗
PubMed2001

Intravascular ultrasound-guided percutaneous transluminal coronary angioplasty with provisional spot stenting for treatment of long coronary lesions.

OBJECTIVES: The purpose of this study was to evaluate the approach of intravascular ultrasound (IVUS)-guided percutaneous transluminal coronary angioplasty (PTCA) with spot stenting (SS) for the treatment of long coronary lesions. BACKGROUND: Treating long coronary lesions with balloon angioplasty results in suboptimal short- and long-term outcomes. Full lesion coverage with traditional stenting (TS) has been associated with a high restenosis rate. METHODS: We prospectively evaluated a consecutive series of 130 long lesions (>15 mm) in 101 patients treated with IVUS-guided PTCA and SS. The results were compared with those of TS in a matched group of patients. Coronary angioplasty was performed with a balloon to vessel ratio of 1:1, according to the IVUS media-to-media diameter of the vessel at the lesion site, to achieve prespecified IVUS criteria: lumen cross-sectional area (CSA) > or =5.5 mm(2) or > or =50% of the vessel CSA at the lesion site. The stents were implanted only in the vessel segment where the criteria were not met. RESULTS: In the SS group, stents were implanted in 67 of 130 lesions, and the mean stent length was shorter than that of lesions in the matched TS group (10.4 +/- 13 mm vs. 32.4 +/- 13 mm, p < 0.005). The 30-day major adverse cardiac event (MACE) rate was similar (5%) for both groups. Angiographic restenosis was 25% with IVUS-guided SS, as compared with 39% in the TS group (p < 0.05). Follow-up MACE and target lesion revascularization rates were lower in the SS group than in the TS group (22% vs. 38% [p < 0.05] and 19% vs. 34% [p < 0.05], respectively). CONCLUSIONS: Intravascular ultrasound-guided SS for the treatment of long coronary lesions is associated with good acute outcome. Angiographic restenosis and follow-up MACE rates were significantly lower than those with TS.

Aged↗
PubMed2001

Long-term clinical outcomes after unprotected left main trunk percutaneous revascularization in 279 patients.

BACKGROUND: Percutaneous coronary revascularization (PCI) has been increasingly applied to unprotected left main trunk (LMT) lesions, with varied long-term success. This study attempts to define the predictors of outcome in this population. METHODS AND RESULTS: Two hundred seventy-nine consecutive patients who had LMT PCI at 1 of 25 sites between 1993 and 1998 were studied. Forty-six percent of these patients were deemed inoperable or at high surgical risk. Thirty-eight patients (13.7%) died in hospital, and the rest were followed up for a mean of 19 months. The 1-year incidence was 24.2% for all-cause mortality, 20.2% for cardiac mortality, 9.8% for myocardial infarction, and 9.4% for CABG. Independent correlates of all-cause mortality were left ventricular ejection fraction </=30%, mitral regurgitation grade 3 or 4, presentation with myocardial infarction and shock, creatinine >/=2.0 mg/dL, and severe lesion calcification. For the 32% of patients <65 years old with left ventricular ejection fraction >30% and without shock, the prevalence of these adverse risk factors was low. No periprocedural deaths were observed in this low-risk subset, and the 1-year mortality was only 3.4%. CONCLUSIONS: Patients undergoing unprotected LMT PCI have frequent serious comorbidities and consequently have high event rates. PCI may be an alternative to CABG for a select proportion of elective patients and may also be appropriate for highly symptomatic inoperable patients. Meticulous follow-up of hospital survivors is required because of the rather high mortality during the first few months after treatment.

Aged↗
PubMed2001

Cerebral protection with filter devices during carotid artery stenting.

BACKGROUND: Distal embolization of debris during percutaneous carotid artery stenting may result in neurological deficit. Filter devices for cerebral protection potentially reduce the risk of embolization. METHODS AND RESULTS: Elective carotid stent implantation using 3 different types of distal filter protection devices was attempted in 88 consecutive lesions (84 patients) in the internal carotid artery that had >70% diameter stenosis (mean, 78.7+/-10.7%). Procedures were performed in 3 different centers. The mean age of the patients was 69+/-8 years, 75% were men, and 35.7% had neurological symptoms. In 86 lesions, a stent was successfully implanted (97.7%). In 83 of these 86 procedures (96.5%), it was possible to position a filter device. In 53% of filters, there was macroscopic evidence of debris. Collected material consisted of lipid-rich macrophages, fibrin material, and cholesterol clefts. Neurological complications during the procedure, in the hospital, and at 30 days of clinical follow-up occurred in only one patient (1.2%). This patient suffered a minor stroke that resolved within 1 week. Two major adverse cardiac events (2.3%) occurred during the 30 days of follow-up. CONCLUSIONS: Filter protection during carotid artery stenting seems feasible and safe. In the present series, the incidence of neurological complications was low.

Aged↗
PubMed2001

Emergency stenting to treat neurological complications occurring after carotid endarterectomy.

OBJECTIVES: The purpose of this study was to assess the efficacy of emergency stent implantation for the treatment of perioperative stroke after carotid endarterectomy (CEA). BACKGROUND: Carotid endarterectomy has been proven safe and effective in reducing the risk of stroke in symptomatic and asymptomatic patients with >60% carotid artery stenosis. However, perioperative stroke has been reported in 1.5% to 9% of CEA cases. The management of such a complication is challenging. Recently, percutaneous transluminal carotid angioplasty with stent deployment has emerged as a valuable and alternative strategy for the treatment of carotid artery disease. METHODS: Between April 1998 and February 2000, 18 of the 995 patients (1.8%) who had CEA in our institution experienced perioperative major or minor neurological complications. Of these, 13 patients underwent emergency carotid angiogram and eventual stent implantation, whereas the remaining five had surgery re-exploration. RESULTS: Carotid angiogram was performed within 20+/-10 min and revealed vessel flow-limiting dissection (five cases) or thrombosis (eight cases). Percutaneous transluminal carotid angioplasty with direct stenting (self-expandable stent) was performed in all 13 cases. Angiographic success was 100%. Complete remission of neurological symptoms occurred in 11 of the 13 patients treated by stent implantation and in one of the five patients treated by surgical re-exploration (p = 0.024). CONCLUSIONS: Stent implantation seems to be a safe and effective strategy in the treatment of perioperative stroke complicating CEA, especially when carotid dissection represents the main anatomic problem.

Aged↗
PubMed2001

Predictors of diffuse and aggressive intra-stent restenosis.

OBJECTIVES: This study was performed to investigate the causes of diffuse and aggressive intra-stent restenosis. BACKGROUND: Although restenosis is usually considered to be a dichotomous variable, there is clinical relevance to the severity of restenosis. It is not known which variables are predictive of diffuse or aggressive intra-stent restenosis. METHODS: A consecutive series of 456 coronary lesions with in-stent restenosis was evaluated for the type of restenosis using quantitative coronary angiography. Restenosis was defined as > or = 50% diameter stenosis at follow-up angiography, diffuse restenosis as a follow-up lesion length > or = 10 mm and aggressive restenosis as either an increase in lesion length from the original lesion or a restenotic narrowing tighter than the original. Clinical, anatomic and procedural characteristics were evaluated for lesions associated with these types of restenosis. RESULTS: Diffuse restenosis was associated with a smaller reference artery diameter, longer lesion length, female gender, longer stent length and the use of coil stents. Aggressive restenosis was more common in women, with the use of Wallstents and with long stent to lesion length ratios. Aggressive restenosis occurred earlier and was more closely associated with symptoms and myocardial infarctions than nonaggressive restenotic lesions. CONCLUSIONS: Markers for diffuse restenosis were also important markers for the presence of any restenosis. A long stent to lesion length ratio is an important marker for aggressive restenosis. When severe forms of in-stent restenosis occur, they tend to present earlier and with more symptoms, including myocardial infarction. More careful consideration of the type of in-stent restenosis may aid in identifying when alternative strategies may be useful.

Coronary Angiography↗
PubMed2001

Intravascular ultrasound criteria for the assessment of the functional significance of intermediate coronary artery stenoses and comparison with fractional flow reserve.

The functional significance of coronary artery stenoses of intermediate severity is important in determining strategy in patient care. Intravascular ultrasound (IVUS) is often used to evaluate coronary stenosis severity. However, at present, few data are available about the role IVUS in the assessment of functional significance of intermediate lesions. Myocardial fractional flow reserve (FFR) <0.75 is a reliable index of a functionally severe coronary stenosis. In 53 lesions we assessed (1) by pressure wire: FFR (index of functional significance), and (2) by IVUS: minimal lumen cross-sectional area (MLA, square millimeters), minimal lumen diameter (MLD, millimeters), lesion length (millimeters), and percent area stenosis at the lesion site. By regression analysis, percent area stenosis and lesion length had a significant inverse correlation with FFR (r = -0.58, p <0.001, r = -0.41, p <0.004, respectively). MLD and MLA showed a significant positive relation with FFR (r = 0.51, p <0.001, r = 0.41, p <0.004, respectively). By using a receiver operating characteristic (ROC) curve, we identified a percent area stenosis > 70% (sensitivity 100%, specificity 68%), a MLD < or = 1.8 mm (sensitivity 100%, specificity 66%), a MLA < or =4.0 mm2 (sensitivity 92%, specificity 56%), and a lesion length of >10 mm (sensitivity 41%, specificity 80%) to be the best cut-off values to fit with a FFR <0.75. The combined evaluation of both percent area stenosis and MLD made the IVUS examination more specific (sensitivity 100%, specificity 76%). In 53 intermediate coronary lesions found by angiography, IVUS area stenosis >70%, MLD < or =1.8 mm, MLA < or =4.0 mm2, and lesion length > 10 mm reliably identified functionally critical intermediate coronary stenoses.

Cardiac Catheterization↗