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Biomedical subjects

A Colombo

Publications and source records attributed to A Colombo.

At least 289 records · Page 16Linked to original sources
PubMed1995

Intracoronary stent insertion after balloon angioplasty of chronic total occlusions.

OBJECTIVES: This retrospective analysis was performed to assess the medium-term effectiveness of implanting intracoronary stents into chronic total occlusions that are successfully opened by balloon angioplasty. BACKGROUND: The value of percutaneous transluminal coronary angioplasty of chronic total occlusions is limited by a very high restenosis rate of 50% to 68%. Intravascular stents have been shown to reduce restenosis in a subset of patients with subtotal stenoses. It has not been demonstrated that the placement of stents into successfully opened chronic total coronary artery occlusions leads to lower rates of restenosis. METHODS: A consecutive series of patients with chronic total coronary occlusions successfully opened by balloon angioplasty received Palmaz-Schatz stents. Patients underwent clinical and angiographic follow-up at a mean of 6 months after stent insertion. Angiographic and clinical results were retrospectively analyzed. RESULTS: Fifty-nine patients underwent stenting of 60 chronic total coronary occlusions, with a 98% rate of successful stent deployment. Complications occurred in 5% of cases, all with subacute thrombosis. Angiographic follow-up was obtained in 88% of patients at a mean of 6 months and demonstrated an angiographic restenosis rate of 20%, with only one reocclusion. Among several variables examined, only the presence of a procedure-related moderate to severe dissection was associated with higher follow-up percent diameter stenoses and clinical events. At a mean of 14 months after stent insertion, 77% of patients remained free of symptoms or clinical events. CONCLUSIONS: The implantation of intracoronary stents into vessels with opened chronic total coronary occlusions is associated with favorable rates of angiographic restenosis and relief of symptoms. A randomized clinical trial comparing balloon angioplasty with stent-assisted balloon angioplasty in the treatment of chronic total coronary occlusions is indicated.

Aged↗
PubMed1995

Effect of infusion and withdrawl of glucose and insulin on gas exchange in injured ventilated patients.

PURPOSE: To evaluate the effect induced on gas exchange and on urea excretion by glucose and insulin infusion in injured patients. The magnitude and time necessary for the full development of the metabolic effect were investigated. METHODS: Six injured patients were investigated. During the first 24 hours, the fasting period, patients received 1 mg/kg*min of glucose; during the second 24 hours, the treatment period, infusion was increased to about the 95% of the energy production rate; during the last 8 hours, (stop period) the infusion rate was again set to 1 mg/kg*min. Gas exchange was determined in two consecutive 12-hour series, for 30 minutes every hour, either during a stabilized treatment or after its variation. Urea excretion was determinated on 4-hour samples. RESULTS: With respect to the fasting period, during the last 4 hours of the treatment period, the energy production rate did not vary; urea excretion (-25%) and oxygen consumption (-9%) decreased significantly. Carbon dioxide production (+16%), total respiratory quotient, and minute ventilation (+5%) increased significantly. Carbon dioxide production varied linearly with time (glucose infusion +1.74 mL/min*m2*h, P < .05; glucose withdrawal -1.89 mL/min*m2*h, P < .01). Minute ventilation decreased only during the withdrawal period by 65 mL/min*m2*h (P < .05). CONCLUSIONS: The infusion of glucose and insulin, in an amount slightly lower than the metabolic expenditure, leads to a consistently reduced amino acid catabolism and to a decreased oxygen consumption, without affecting energy requirements. Although it leads to an increase of carbon dioxide production, the measured change is so small and slow that it is not harmful unless there is severe respiratory insufficiency.

Adolescent↗
PubMed1995

B-mode color sonographic images in obstetrics and gynecology: preliminary report.

The standard B-mode image shows 256 levels of gray, but the human eye can only differentiate 8-16 shades of gray. Color vision theoretically has several advantages in comparison with gray scale, because the human eye can distinguish 128 fully saturated hues and about 350,000 shades. In 1992, B-mode color maps were introduced in our clinical practice, to establish whether this technology was able to detect the smallest contrast differences better than the gray-scale map and therefore to increase diagnostic accuracy. This paper describes our experience with the technique and reports B-mode color images of clinical complications in obstetrics and gynecology. We use the color figures to illustrate this new technology and to demonstrate the advantages of the increased sensitivity of the human eye to color in different clinical situations. We conclude that the use of B-mode color maps does not change the ultrasonic diagnosis, but does enhance our ability to study and evaluate the morphological structure of different tissues, compared to the gray-scale map alone.

Female↗
PubMed1995

HIV infection and invasive cervical carcinoma in an Italian population: the need for closer screening programmes in seropositive patients.

OBJECTIVE: To evaluate in an Italian population the prevalence, characteristics at first diagnosis and outcome of HIV-seropositive individuals with cervical carcinoma referred to a tertiary-care institution. DESIGN: A retrospective evaluation of all patients referred for invasive cervical carcinoma from 1991 to 1994. SETTING: The departments of obstetrics and gynaecology, and radiotherapy at San Gerardo Hospital, University of Milan, Italy. PATIENTS: A total of 340 women were treated over a 3-year period (186 aged < 50 years). Six patients were found to be HIV-seropositive. INTERVENTIONS: Seropositive patients were treated according to current institutional protocols, irrespective of HIV status. Four underwent radiotherapy and two radical hysterectomy as primary treatment. RESULTS: Although five HIV-seropositive patients were known to be infected 13-81 months before diagnosis of cervical cancer, none had received a PAP smear in the last year and only one in the last 2 years. HIV patients were younger than general population (P = 0.02), with a significant history of intravenous drug use (P = 0.000001) and with more advanced disease (P = 0.04). Two HIV-positive patients also received polychemotherapy (one adjuvant and one salvage treatment) and both completed the planned treatment. Within 24 months two patients had died of cancer and one of AIDS; one is alive with AIDS and cancer and two are free of disease. CONCLUSIONS: This study confirms that in a southern European population, HIV-seropositive women present to tertiary-care institutions with more advanced disease and have a poorer prognosis than the general population. Strict screening programs for cervical dysplasia and cancer are warranted for HIV-seropositive patients.

Adult↗
PubMed1995

[Antibiotic prophylaxis with mezlocillin in elective biliary surgery].

The authors report their experience of antibiotic prophylaxis in elective biliary surgery pertinent to 246 operated patients treated with short-term prophylaxis with mezlocillin. This method has turned out to be efficacious in reducing postoperative infections incidence, particularly in simple cholecystectomy. Therefore the authors advise using such a procedure in this frequent operation too.

Biliary Tract Surgical Procedures↗
PubMed1995

Extracorporeal membrane oxygenation with veno-venous bypass and apneic oxygenation for treatment of severe neonatal respiratory failure.

Seven newborn infants with life-threatening respiratory failure were treated with veno-venous (V-V) extracorporeal lung support and apneic oxygenation after maximal ventilatory and pharmacological treatment failed. Diagnosis were meconium aspiration syndrome in 3 cases, respiratory distress syndrome in 2, sepsis in 1, congenital diaphragmatic hernia in 1. Before ECMO 6 infants received tolazoline, 4 surfactant, 3 high frequency ventilation, 1 prostaglandin E, 1 epoprostenol, 2 nitric oxide. Newborns were highly hypoxemic at admission and all but one underwent rescue cannulation. V-V bypass was performed with a single lumen single cannula and tidal flow was generated by an alternating clamp using a non-occlusive roller pump. The mean duration of bypass was 162.4 +/- 162.3 hours and infants were extubated 94.5 +/- 74.8 hours after decannulation. Five newborns survived and two died. Growth and neurologic development of the older children is normal. The extracorporeal lung support with V-V bypass associated with apneic oxygenation was effective in reversing severe neonatal respiratory failure unresponsive to maximal ventilatory and pharmacological support. An early referral, prior to meeting ECMO criteria, is important in order to avoid hypoxic complications preceding ECMO.

Adrenergic alpha-Antagonists↗
PubMed1994

Protein S and protein C anticoagulant activity in acute and chronic cardiac ischemic syndromes. Relationship to inflammation, complement activation and in vivo thrombin activity.

Protein S (PS) and protein C (PC) anticoagulant activities and thrombin-antithrombin complex (TAT) were measured in 20 patients with AIS, 25 patients with chronic stable angina (CSA) and a control group (C). Although plasma levels of TAT were significantly elevated in patients with CSA (p < 0.01 vs C), they were much higher in patients with AIS (p < 0.001 vs CSA). PC anticoagulant activity was similar in patients and controls. At variance, PS anticoagulant activity was lower in patients with AIS than in those with CSA and controls (p < 0.05), reflecting differences in total PS and C4B-binding protein (C4B-BP) antigen possibly resulting from involvement in the mechanisms of inflammation, complement activation and acute-phase response. The ratios of anticoagulant PS and PC to procoagulant vitamin K-dependent factors IX and II were reduced in AIS patients (0.05 > p > 0.005 vs C). In addition, the ratios of anticoagulant PC and PS to factor IX were lower in patients with AIS than in those with CSA (p < 0.05). These results indicate that in patients with acute ischemic cardiac syndromes the markedly increased in vivo thrombin generation is associated with an unbalance between coagulant and anticoagulant vitamin K-dependent factors.

Acute Disease↗
PubMed1994

Benefit of intracoronary ultrasound in the deployment of Palmaz-Schatz stents.

OBJECTIVES: This study was designed to evaluate the changes in intrastent and angiographic dimensions when intravascular ultrasound imaging is used to direct the deployment of balloon-expandable Palmaz-Schatz stents in coronary arteries and saphenous vein grafts. BACKGROUND: Intravascular ultrasound provides more information than angiography in the imaging of intravascular structures. Previous studies have shown that obtaining a larger lumen (greater "acute gain") with coronary interventions such as stenting leads to less restenosis and subacute thrombosis. It is not clear whether the information obtained by intravascular ultrasound can be used to obtain a greater acute gain in lumen dimensions. METHODS: Forty consecutive patients undergoing Palmaz-Schatz stent implantation had intravascular ultrasound imaging performed after a good angiographic appearance was obtained. If the stent did not appear adequately expanded by intravascular ultrasound, or if the struts were poorly apposed to the arterial wall, further stent dilation with larger balloons or higher pressure inflations were performed. Twenty-nine patients had subsequent intravascular ultrasound imaging. Intrastent diameters and areas were compared from the initial to the final intravascular ultrasound studies. RESULTS: Of the 40 patients studied, only 5 (13%) had an adequate result by intravascular ultrasound despite an acceptable angiographic appearance in all patients. Six additional patients did not undergo subsequent intravascular ultrasound imaging. The other 29 patients all demonstrated a significant increase in intrastent minimal diameter (mean 19%), major diameter (11%) and cross-sectional area (34%) (p < 0.001 for all measurements). CONCLUSIONS: The use of intravascular ultrasound imaging in the deployment of balloon-expandable Palmaz-Schatz stents leads to a significant increase in intrastent dimensions (greater "acute gain").

Aged↗
PubMed1994

Favourable results of treatment of narrowed saphenous vein grafts with Palmaz-Schatz stent implantation.

Although conventional balloon angioplasty of saphenous vein grafts can be performed with an acceptable acute success and complication rate, restenosis remains a major problem. However, this may be overcome by the implantation of Palmaz-Schatz stents. Palmaz-Schatz stent deployment was performed in our institution in 43 patients who were referred for PTCA of stenosed saphenous vein grafts. Thirty-seven were located at the mid-portion of the graft, seven at the ostium and six at the distal anastomosis. Overall, we used 59 standard length (15 mm) Palmaz-Schatz stents and 22 short (7 mm) stents. In 15 lesions (30%) multiple stents were implanted in tandem to treat diffuse disease. Angiographic success was achieved in 47 of the 50 attempted lesions (94%). Major cardiac complications occurred in three patients. Two patients had procedures complicated by the development of a Q wave myocardial infarction, one of whom underwent urgent CABG. One patient died. There was no episode of subacute thrombosis. The angiographic follow-up of 37 lesions (80% of eligible lesions) at a mean time of 5 +/- 2 months (range 1-8) showed a restenosis rate of 11% and residual post-stent diameter stenosis was associated with a significantly higher restenosis rate. However, no restenosis occurred in lesions receiving multiple stents. Clinical follow-up was performed in all patients, and at a mean of 25 months after the procedure, 64% were free from clinical events, including recurrent angina. Palmaz-Schatz stent implantation is an effective and safe procedure to treat narrowed vein grafts.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Accuracy of quantifying coronary hydroxyapatite with electron beam tomography.

RATIONALE AND OBJECTIVES: The electron beam tomography coronary calcium score continues to be used without experimental validation. To determine its accuracy, a series of experiments was performed. METHODS: A chest phantom model was constructed with coronary arteries represented by cylindrical holes containing hydroxyapatite granules embedded in a gelatin matrix to simulate coronary arteries. Experiments were performed to determine the relationship between the mass of hydroxyapatite in each of these arteries, the coronary calcium score currently used in coronary screening, and an alternative method of estimating mass from the images. The model was scanned with equal amounts of hydroxyapatite in each artery: 1) when the cylindrical heart was rotated 36 degrees 10 times between scans, and 2) when the particle diameters varied from 0.1 mm to 4 mm. The scores were calculated, and a subtraction algorithm was applied to estimate the exact mass of hydroxyapatite in each artery. RESULTS: The hydroxyapatite scores varied by 42% with position and by 1.54 x 10(6)% with particle diameter. The estimated masses from the subtraction algorithm were more stable with position and particle size, with maximum percent errors of 10% and 14% for position and particle size, respectively. CONCLUSIONS: These results suggest that the coronary calcium score is invalid, and that more precise and clinically relevant methods, such as the arterial summation method, should be rigorously tested in clinical studies.

Algorithms↗
PubMed1994

Preliminary experience with intravascular ultrasound guided Palmaz-Schatz coronary stenting: the acute and short-term results on a consecutive series of patients.

The purpose of this study was to prospectively test the hypothesis that systemic anticoagulation is not needed following coronary stenting when adequate stent expansion is achieved and documented and other flow limitations eliminated. Intravascular ultrasound (IVUS) was used to confirm adequate stent expansion, which was defined as good plaque compression together with the achievement of an intrastent lumen cross-sectional area (CSA) that was greater than 40% of the average reference vessel CSA. In this prospective study, Palmaz-Schatz coronary stenting was performed on 343 lesions in 263 consecutive patients. Primary stenting was successful in 254 patients (96.6%) and 332 lesions (96.8%). All patients with successful primary stenting underwent IVUS imaging except nine patients (13 lesions) that did not have an IVUS evaluation for technical reasons and three patients (4 lesions) in which IVUS was unsuccessful. The initial IVUS performed after achieving an acceptable angiographic result revealed inadequate stent expansion in 191 patients (79%) and 244 lesions (77%). After further dilatation, final adequate stent expansion was accomplished in 230 patients and 301 lesions. These patients were treated with Ticlopidine 250 mg twice per day for 2 months and did not receive postprocedure anticoagulation. There was one acute stent thrombosis (0.3%) that occurred in a lesion with slow flow and an inadequately expanded stent. There was no subacute stent thrombosis and no bleeding or vascular complications. We conclude that when adequate stent expansion is achieved and confirmed and other flow limiting lesions eliminated, that systemic anticoagulation after the stent procedure is not necessary.

Aged↗
PubMed1994

Survival after percutaneous transluminal coronary angioplasty in patients with severe left ventricular dysfunction.

To assess the effects of coronary angioplasty in patients with severe left ventricular dysfunction, the results of procedures, performed between 1987 and 1991, in 100 patients (90 male) with left ventricular function < or = 0.35 (range, 0.20 to 0.35) and anginal symptoms were analyzed. Mean age was 62 +/- 10 years (range, 38 to 85 years). Ninety-five patients had previous myocardial infarction and 27 patients had previous coronary artery bypass grafting. Unstable angina was present in 81 percent of patients. Single-vessel disease was present in 6 patients, double vessel was present in 31 patients, and triple-vessel disease was present in 63 patients. Percutaneous transluminal coronary angioplasty (PTCA) was attempted on 164 vessels, 27 of these with chronic total occlusion. The overall angiographic success rate was 84 percent. Myocardial infarction occurred in four patients, six patients underwent urgent coronary bypass surgery, and seven patients died of cardiac causes. There was a 9 percent incidence of total in hospital mortality. Major complications were significantly more frequent in patients with triple-vessel disease. Clinical success was achieved in 75 patients, 55 of these with incomplete revascularization. Long-term follow-up (mean, 19 +/- 7 months) was available in all patients with clinical success. Thirteen patients had repeated PTCA, 8 patients had coronary surgery, and 13 patients died. In conclusion, in patients with severe left ventricular dysfunction, acute complications and late mortality rate are high. Patients with triple-vessel disease are a higher risk subset and have no long-term benefits by PTCA.

Angioplasty, Balloon, Coronary↗
PubMed1994

Paracervical anesthesia for outpatient hysteroscopy.

One hundred seventy-seven women aged 41 +/- 8 (mean +/- SD) years, referred for evaluation of excessive uterine bleeding, were enrolled in an open-label randomized trial to evaluate the efficacy of local anesthesia before hysteroscopy in an outpatient population. The patients underwent hysteroscopy and endometrial biopsy with paracervical block by 10 mL of 1% mepivacaine hydrochloride solution (n = 87) or no local anesthesia (n = 90) and assessed lower abdominal and pelvic pain according to a 10-point linear analog scale. The mean +/- SD pain score was 4.5 +/- 2.0 at hysteroscopy and 5.2 +/- 2.1 at endometrial biopsy in the 87 subjects given a paracervical block versus 4.9 +/- 2.2 and 5.7 +/- 2.4 in the 90 women not given local anesthesia, without statistically significant differences. Paracervical anesthesia for routine outpatient hysteroscopy in premenopausal women may be superfluous.

Adult↗
PubMed1993

Treatment of simple and complex coronary stenosis using rotational ablation followed by low pressure balloon angioplasty.

High speed coronary rotational ablation followed by adjunctive low pressure coronary balloon angioplasty was used in 166 patients. Complex lesions were present in 63% of patients. Clinical success was achieved in 157 patients (95%). Angiographic success rate was 10% in A lesions, 95% in B1 lesions, 98% in B2 lesions, and 93% in C lesions. Mean vessel lumen diameter has increased from 0.4 mm to 1.4 mm after rotational ablation and to 2.3 mm following adjunctive balloon angioplasty. Left ventricular dysfunction, the presence of total occlusion, and the severity of stenosis before the procedure were predictive of clinical failure. There were three abrupt vessel closures (1.8%) with one Q wave myocardial infarction. Non-Q wave myocardial infarction occurred in 14 patients (8.4%) and three patients died during hospitalisation (1.8%). We conclude that rotational atherectomy followed by adjunctive low pressure balloon angioplasty gives comparable high success rates in different coronary lesions.

Angioplasty, Balloon, Coronary↗
PubMed1993

"Kissing" stents for bifurcational coronary lesion.

The coronary stents implantation into each vessel of a bifurcational lesion ("kissing" stents) in two patients is reported. The first patient had two short "kissing" stents implanted in an ostial lesion of the left anterior descending and the intermediate branch. The second patient had successful "kissing" stents implantation in the bifurcational lesion of the left main coronary artery.

Aged↗