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Biomedical subjects

M Amor

Publications and source records attributed to M Amor.

At least 37 records · Page 2Linked to original sources
PubMed1995

Palmaz stent placement in iliac and femoropopliteal arteries: primary and secondary patency in 310 patients with 2-4-year follow-up.

PURPOSE: To define the long-term outcome of stent placement in iliac and femoropopliteal arteries. MATERIALS AND METHODS: Three hundred ten patients received 418 balloon-expandable Palmaz stents. Two hundred thirty stents were implanted in iliac arteries of 184 patients, and 188 stents were implanted in femoropopliteal arteries in 126 patients. Restenosis rates were based on results of angiography performed 4-6 months after stent placement. Long-term patency rates were determined with duplex ultrasound. RESULTS: Immediate procedural success was achieved in 309 patients. Acute thrombosis ( < 24 hours) occurred in five patients, and immediate clinical success in 288. The 30-day mortality and morbidity rates were 0% and 8%, respectively. Angiography performed at 6 months in 299 patients revealed restenosis rates of 0.5% in iliac lesions, 11% in superficial femoral artery (SFA) lesions, and 20% in popliteal lesions. Survival analysis revealed 4-year primary patency rates of 86% +/- 4.1 for iliac artery lesions, 65% +/- 7.5 for SFA lesions, and 50% +/- 17.7 for popliteal artery lesions. Most restenotic lesions were successfully treated with repeat angioplasty. CONCLUSION: Implantation of Palmaz stents in iliac arteries allows long-term primary patency to be maintained in most patients.

Aged↗
PubMed1995

Percutaneous peripheral atherectomy using the rotablator: a single-center experience.

PURPOSE: In order to assess the role of percutaneous peripheral rotational ablation using Rotablator, 150 symptomatic patients (94 males, 56 females; mean age 73 +/- 1 years, range 42 to 90) having 212 complex peripheral vascular lesions were treated. METHODS: Fifty percent of lesions were below the knee; 65% of patients had severe claudication, 11% moderate (24% were in stage III or IV Fontaine classification). The femoral lesions were significantly longer than those at other sites (5.7 +/- 0.4 versus 2.9 +/- 0.3 cm, p < 0.001). The mean length was 4.0 +/- 0.2 cm (range 1 to 20). All the lesions were considered complex; 93% of the lesions were clacified, and 63% were located at a bifurcation. Complementary balloon dilation (percutaneous transluminal angioplasty [PTA]) was significantly (p < 0.001) more frequent in femoropopliteal lesions (70 PTAs in 86 femoral arteries, 10 PTAs in 19 popliteal arteries) than in distal leg lesions (14 in 106 arteries). RESULTS: After Rotablator therapy alone, the percent stenosis decreased from 81.0% +/- 0.8% to 18.0% +/- 1.1%. The residual stenosis was greater at the femoral (44%) than at the distal level (19%) (p < 0.01). Adjunctive PTA (47 lesions) lowered residual stenosis to 10% at the femoral level and 3% at the distal level. Thirty-seven intraprocedural complications occurred (spasm, thrombosis, dissection, perforation, distal emboli, no reflow); seven procedures subsequently failed for an overall technical success of 97%. The mean follow-up period was 14.4 +/- 1.0 months (range 1 to 51). Among 125 patients having a follow-up period > or = 4 months, 114 patients representing 163 lesions underwent angiography. One hundred twenty-three lesions (76%) were patent, and 40 lesions (24%) showed restenosis (> or = 50% luminal narrowing) of 82.0% +/- 21%. The restenosis rate was higher in femoral (36%) than in distal (21%) or popliteal arteries (7%). Restenosis was more frequent for all lesions > or = 7 cm (p < 0.001) and for both above- and below-knee locations: 55% versus 19% for < 7 cm at the femoropopliteal level (p < 0.03), and 80% versus 18% at the distal level (p < 0.01). CONCLUSIONS: In our experience, percutaneous peripheral rotational ablation has taken a pre-eminent position in the treatment of distal leg arteries, especially in complex lesions. Our results have led us to broaden its indications to complex vascular lesions < or = 6 cm. In particular, the use of this technique for treatment of runoff vessels should improve the long-term patency of proximal PTA and bypass grafts. This device has become indispensable in our laboratory, where Rotablator therapy comprises 15% of all PTA procedures.

Adult↗
PubMed1995

A new access site management tool: the Angio-Seal hemostatic puncture closure device.

PURPOSE: Given the increasing number of percutaneously applied endovascular therapies, the incidence of access-related vascular complications can be expected to rise, particularly in association with those techniques requiring large sheaths or anticoagulation. The need exists for a safe, easy to use, and effective hemostatic technique to replace the labor-intensive method of manual compression. METHODS: A bioabsorbable, sheath-delivered vascular device (Angio-Seal) has been developed that deposits a small collagen plug within the arterial wall to mechanically seal the puncture defect. An anchor connected by suture to the plug is first deployed in the arterial lumen and pulled flush against the interior wall to guard against intraluminal deposition of the collagen. RESULTS: The Angio-Seal device was deployed successfully in 80 (96%) of 83 attempts involving common femoral arteries accessed for peripheral angioplasty (n = 30), coronary angiography (n = 30), and coronary angioplasty (n = 16). Three popliteal artery access sites and one femoropopliteal bypass graft were also treated. Hemostasis was immediate in 78 cases (98%); 2 sites required a 5-minute manual compression to effect a secure seal. Three devices failed to deploy, and manual pressure was used to close the puncture. Nondeployment did not cause any sequelae, and no complications were encountered with the technique. CONCLUSIONS: This novel vascular closure device is quick (< 1 minute application time) and simple to use, providing a positive seal of common femoral artery puncture sites for both peripheral and coronary interventions. It appears to be a reliable alternative to standard manual hemostasis.

Angioplasty↗
PubMed1995

[Rare causes of ossification of the posterior common vertebral ligament causing cervical compression. Apropos of 2 cases].

The ossification of the posterior longitudinal is always responsible of cervical myelopathy. Radiological study and the CT scan, are able to precise the level, the morphologic and associated abnormalities of this lesion. Two cases of ossification of the posterior longitudinal ligamentum with cervical myelopathy are reported. The radiologic studies determined the etiology, in the first case, it was fluorosis and the second DISH disease.

Aged↗
PubMed1994

Initial experience with the Cragg Endopro System 1 for intraluminal treatment of peripheral vascular disease.

PURPOSE: To evaluate the safety and efficacy of a new covered stent, the Cragg Endopro System 1, for intraluminal treatment of peripheral vascular disease in the iliac and femoropopliteal arteries. METHODS: Forty symptomatic patients with predominantly lengthy stenotic (24) or occlusive (13) lesions or aneurysms (3) in the iliac (19), femoral (19), or popliteal (2) arteries were treated percutaneously with balloon angioplasty followed by implantation of the self-expanding nitinol Cragg stent covered by a woven polyester fabric coated with low-molecular-weight heparin. The mean length of femoropopliteal lesions was 13.0 +/- 1.8 cm, as compared to 6.7 +/- 0.8 cm (p < 0.01) for iliac lesions. Mean percent stenosis was 89% +/- 2% with no significant difference between the arterial segments. RESULTS: With a total of 52 covered stents implanted, technical success was achieved in 98% (39/40 patients). One tortuous femoral artery aneurysm was not satisfactorily excluded to prevent leakage. Clinical success was seen in all patients with demonstrable improvements in the claudication stage and the ankle-brachial index from a mean 0.54 to 0.92. Three local complications (one hematoma, two false aneurysms) required surgical repair. One distal embolism, one acute thrombosis, and three subacute thromboses were encountered and successfully treated by thrombolysis and/or surgery. One patient with two iliac stents developed contralateral common iliac artery occlusion from a stent partially obstructing the aorta; placement of a covered stent in the blocked artery re-established normal flow. Over an 8-month follow-up with arteriographic re-examination, all iliac stents remained patent. At the femoropopliteal level, two stents were occluded at 4 months; one was successfully dilated, but the other required surgical bypass grafting. A third patient developed a stenotic lesion proximal to the stent; dilation restored adequate inflow to the stent. CONCLUSIONS: The Cragg Endopro System 1 appears to be effective as an "internal bypass" for iliac and femoropopliteal occlusive disease. More complications and restenosis were seen in femoropopliteal implantations; however, a change in postoperative medication may improve these results. Long-term results will determine if the Cragg Endopro System 1 can achieve a patency equal to conventional bypass grafting.

Aged↗
PubMed1993

Percutaneous peripheral rotational ablation using the Rotablator: immediate and mid term results. Single center experience concerning 146 lesions treated.

In order to assess the role of percutaneous peripheral rotational ablation using Rotablator (PPRA), 95 symptomatic patients (58 M, 37 F, m. age: 77 +/- 1 y) (r: 50-90 y) having 146 peripheral vascular lesions (PVL) were treated by PPRA. 59% were below the knee and 41% above. The runoff status (n of distal leg art. involved) was as follows: 3:52 pts, 2:23 pts, 1:14 pts, 0:6 pts. The femoral lesions were significantly longer than those at other sites (5.27 +/- 0.43 vs 2.97 +/- 0.3 cm) (p < 0.001). The mean length was 3.73 +/- 0.26 cm (r: 1-20 cm). Complementary PTA was significantly (p < 0.001) more frequent in femoro-popliteal (32 PTA/48 Fem, 5 PTA/12 Pop) than in distal leg lesions (10/86.). RESULTS. After PPRA alone (99 PVL) the stenosis % decreased from 81 +/- 0.75 to 18 +/- 1.1. The residual stenosis was greater at femoral (26 +/- 2.3%) than at distal leg level (16 +/- 1.2%) (p < 0.01). Complementary PTA (47 PVL) lowered residual stenosis from 44% to 13%. 52 complications (spasm, perforation, dissection, distal emboli, no reflow, others) were cured in 47 PVL. Thus our primary technical success per PVL was 97% and per pt 95%. The mean follow-up period was 11 +/- 1 mths (r: 1-37 m). Among 78 pts having a follow-up period > or = 4 mths, 74 pts representing 115 treated PVL underwent an angiography control (2 deaths, 2 lost for follow-up). 87 lesions (76%) showed no restenosis and 28 lesions (34%) showed restenosis of 83 +/- 2.4% (r: 50-100%). The restenosis rate was higher in femoral (12/21: 36%) than in distal (15/58: 21%) or popliteal arteries (1/8: 12%). Restenosis was more frequent for PVL > or = 7 cm (67% vs 16%) (p < 0.001) at all sites. This result together with the complication rate would seem to indicate that lesions > or = 6.7 cm would be a limitation for PPRA. CONCLUSIONS. In our experience Percutaneous Peripheral Rotational Ablation has taken a pre-eminent position in the treatment of distal leg arteries. Our results lead us to broaden its indications to complex vascular lesions. The possibility of runoff treatment should allow an improvement in the long-term patency of PTA and bypass grafts.

Aged↗
PubMed1993

[Peripheral arterial angioplasty: value of the popliteal approach. Apropos of 30 cases].

The percutaneous common femoral arterial approach is usually used for endovascular management of lower limb arterial disease. This approach is sometimes impracticable because the femoral artery is the site of severe calcific atheromatous lesions which prevent arterial puncture or, when the superficial femoral lesions are ostial or proximal, make it impossible to position the introducer and advance the guide wire. The popliteal artery then becomes very useful for treating these lesions by a retrograde approach. Similarly, superficial femoral lesions which cannot be successfully dilated by the anterograde femoral approach may justify retrograde catheterisation via the popliteal artery. Between May 1988 and August 1991, the authors used the retrograde popliteal approach in 30 cases. They obtained 24 successes, 12 of which were associated with the implantation of an endoprosthesis. There was 1 complication at the puncture site a popliteal arteriovenous fistula was created but was treated successfully by surgery.

Adult↗
PubMed1988

Effect of diltiazem on myocardial infarct size estimated by enzyme release, serial thallium-201 single-photon emission computed tomography and radionuclide angiography.

Diltiazem is a calcium antagonist with demonstrated experimental cardioprotective effects. Its effects on myocardial infarct size were studied in 34 patients admitted within 6 hours after the first symptoms of acute myocardial infarction. These patients were randomized, double-blind to placebo or diltiazem (10-mg intravenous bolus followed by 15 mg/hr intravenous infusion during 72 hours, followed by 4 X 60 mg during 21 days). Myocardial infarct size was assessed by plasma creatine kinase and creatine kinase-MB indexes, perfusion defect scores using single-photon emission computed tomography with thallium-201 and left ventricular ejection fraction measured by radionuclide angiography. Tomographic and angiographic scanning was performed serially before randomization, after 48 hours and 21 days later. Groups were comparable in terms of age, sex, inclusion time and baseline infarct location and size. Results showed no difference in creatine kinase and creatine kinase-MB data between controls and treated patients, a significant decrease in the perfusion defect scores in the diltiazem group (+0.1 +/- 3.0 placebo vs -2.2 +/- 1.9 diltiazem, p less than 0.02) and a better ejection fraction recovery in the diltiazem group (-4.2 +/- 7.4 placebo vs +7.7 +/- 11.2 diltiazem, p less than 0.05). Myocardial infarct size estimates from perfusion defect scores and enzyme data were closely correlated. These preliminary results suggest that diltiazem may reduce ischemic injury in acute myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical Enzyme Tests↗
PubMed1988

Mutation in the CYP21B gene (Ile-172----Asn) causes steroid 21-hydroxylase deficiency.

Steroid 21-hydroxylase deficiency is the most common cause of congenital adrenal hyperplasia. It results from a deficiency in a specific cytochrome P450, P450c21 (P450XXIA). The gene encoding this protein (CYP21B) and a closely linked pseudogene (CYP21A) are located in the HLA complex on chromosome 6p. Many mutant alleles are associated with deletions of CYP21B; we report the cloning and characterization of a nondeleted mutant CYP21B gene. This mutant gene is expressed on transfection into mouse Y1 adrenal cells, producing mRNA levels similar to those seen after transfection of the normal CYP21B gene. In codon 172 of the mutant gene, the normal codon ATC, encoding isoleucine, has been changed to AAC, encoding asparagine. This mutation is normally present in the CYP21A pseudogene, so that it may have been transferred to the mutant CYP21B gene by gene conversion. Hybridization of oligonucleotide probes corresponding to this and two other mutations normally present in CYP21A demonstrated that 4 out of 20 patients carried the codon 172 mutation; in one of these patients, the mutation was present as part of a larger gene conversion involving at least exons 3-6. Gene conversion may be a frequent cause of 21-hydroxylase deficiency alleles due to the presence of six chi-like sequences (GCTGGGG) in the CYP21 genes and the close proximity of the CYP21A pseudogene, which has several potentially deleterious mutations.

Adrenal Hyperplasia, Congenital↗
PubMed1988

Sustained improvement in myocardial perfusion four to six years after PTCA in patients with a satisfactory angiographic result, six months after the procedure.

Of 46 consecutive patients who underwent percutaneous transluminal coronary angioplasty (PTCA) from April 1980 to August 1982 and who had a satisfactory angiographic result six months later, one died of cancer and 41 had a detailed evaluation with exercise single-photon emission computed tomography (SPECT, 40 patients) or repeat coronary angiography (one patient), 48-78 months after the procedure. During follow-up, two patients had recurrent angina due to progression of coronary artery disease requiring a second PTCA procedure of another coronary artery; one of them later had a limited myocardial infarction in an area supplied by the vessel initially dilated. At follow-up, only one patient had definite angina. All but one patient had a negative exercise test. Myocardial perfusion during exercise in the PTCA-related area, assessed by SPECT, was normal in 90% of the patients and showed a limited defect due to reversible ischaemia in the remaining four (10%). It is concluded that patients with a less than 50% stenosis six months after PTCA show sustained improvement in their functional status and myocardial perfusion, four to six years after the procedure suggesting continued patency of the coronary artery.

Adult↗
PubMed1988

Nonsense mutation causing steroid 21-hydroxylase deficiency.

We determined the sequence of a mutant CYP21B gene isolated from a patient with the severe, "salt-wasting" form of congenital adrenal hyperplasia due to steroid 21-hydroxylase deficiency. Codon 318 in this gene is changed from CAG, encoding glutamine, to TAG, a nonsense codon. This is predicted to result in a completely nonfunctional enzyme due to premature termination of translation. In addition, when the cloned mutant gene was transfected into mouse Y1 adrenal cells, the resulting mRNA levels were decreased compared with transfected normal CYP21B genes. This mutation was carried by 3 of 20 unrelated patients with 21-hydroxylase deficiency alleles as determined by hybridization with a specific oligonucleotide probe. This mutation is also seen in the normal CYP21A pseudogene, so that its presence in the abnormal CYP21B gene may be the result of a gene conversion event.

Adrenal Hyperplasia, Congenital↗
PubMed1987

Effect of flecainide on left ventricular ejection fraction.

Antiarrhythmic agents may depress cardiac contractility and worsen heart failure. Flecainide is an effective antiarrhythmic drug, but when administered orally in patients with left ventricular (LV) dysfunction, its effect on LV function is unknown. To assess the effects of flecainide on cardiac function, LV ejection fraction (LVEF) was measured by radionuclide ventriculography in 36 patients with LV dysfunction (LVEF less than or equal to 40%), prior to, and 7 days after, drug therapy was initiated. To analyse the possibility of a dose-dependent effect on LVEF, 18 patients received 200 mg day-1 of flecainide and 18 patients with an identical initial LVEF (27 +/- 8 vs 27 +/- 9) (NS) received 300 mg day-1. The study was stopped in 7 patients because of severe cardiac adverse effects; in these patients the LVEF was significantly lower (15 +/- 7) than that of the 29 patients who completed the protocol (27 +/- 8) (P less than 0.01). In patients who completed the protocol, there was no significant change in LVEF either with a daily dosage of flecainide of 200 mg day-1 (27 +/- 8 vs 27 +/- 8) or with 300 mg day-1 (27 +/- 9 vs 28 +/- 13). Thus, in the patients with LV dysfunction studied, oral flecainide did not significantly affect LV function either with a low or with the usual daily dosage. However, in patients with severe impairment of LV function (LVEF less than 30%) flecainide must be used carefully owing to a higher incidence of adverse effects on cardiac rhythm.

Arrhythmias, Cardiac↗
PubMed1987

[Prognostic value of a new perfusion index calculated from coronarography].

A new perfusion index was determined from the study of the coronary vascular bed in 8 myocardial territories: upper septal, lower septal, upper anterior, lower anterior, apical, lateral, posterior and inferior. Stenosis of a vessel reduces perfusion in all territories fed by that vessel, downstream of the stenosis. The perfusion index is calculated by adding up the lesions in all 8 territories. In a population of 418 consecutive patients who had undergone coronary arteriography in 1972 and 1973, survival was evaluated according to the perfusion index and to those parameters which classically have the greatest influence on survival. The perfusion index came out as the most important prognostic factor since such parameters as the number of stenotic vessels and ventricular kinetics lose their prognostic value when adjusted to that index. According to the perfusion index, the 8-year prognosis is the same as in subjects without coronary disease when the reduction in overall perfusion does not exceed 40%. With a 40 to 79% reduction the death risk at 8 years is 30% whatever the exact percentage in each individual. When perfusion is reduced by 80% the death risk at 8 years rises to 72%. This perfusion index, easy to determine, provides a better evaluation of prognosis than the conventional parameters.

Adult↗
PubMed1986

[Cardiac radionuclide tomography with gamma emitters].

Two types of radioisotope tomography have been developed: single photon emission computed tomography and positron emission tomography. Tomography of the heart meets with several problems due to the mobility and obliquity of that organ and to the heterogeneity of surrounding tissues. Compared with planar tomography, myocardial tomography with thallium 201 improves the detection of ischaemic and sub-ischaemic areas in myocardial infarction and chronic coronary disease. In spite of some technical limitations, tomography with labelled red cells is very helpful to determine pre-operative size and location of aneurysms.

Coronary Disease↗
PubMed1985

Liver mRNA probes disclose two cytochrome P-450 genes duplicated in tandem with the complement C4 loci of the mouse H-2S region.

A search for uncharacterized genes of the S region of the murine H-2 major histocompatibility complex was undertaken; a series of cosmid clones previously aligned by overlap hybridizations were used as radiolabeled probes. Sequences hybridizing with liver poly(A)+ RNA were found within a cosmid covering a region 3' to the C4-Slp gene (the gene encoding the hemolytically inactive isoform of the fourth component of serum complement). Radiolabeled, short cDNA complementary to liver poly(A)+ RNA was used to establish the transcriptional polarity of the newly detected gene and to define fragments containing its 3' end. DNA sequence analyses and comparisons with porcine peptides established that the gene encodes the enzyme steroid 21-hydroxylase (EC 1.14.99.10), a cytochrome P-450 often referred to as P-450(C21), whose major site of expression is the adrenal gland. Two copies of the P-450(C21) gene, very similar yet distinguishable by restriction endonuclease analysis, were found individually associated with C4 and C4-Slp, genes that encode isoforms of mouse fourth component of complement. One of the P-450(C21) genes is coamplified with C4-Slp in H-2w7, a haplotype carrying a rare elongation of the S region. Comparisons with other members of the P-450 gene family show that the P-450(C21) genes encode peptides of extraordinary evolutionary conservation. The detection of a liver transcript of P-450(C21) raises the issue of the specific metabolic role of this enzyme in this organ and may have implications for the interpretation of human congenital adrenal hyperplasia.

Amino Acid Sequence↗
PubMed1985

[Exertion isotope tests in coronary insufficiency. Comparison with isotopic ventriculography and myocardial scintigraphy].

Very few studies have been described comparing the value of exercise myocardial scintigraphy and left ventricular angioscintigraphy. The authors designed a study comparing these two investigations with conventional exercise stress testing and coronary angiography. The isotopic investigations were carried out within 48 hours of coronary angiography. A total of 143 patients undergoing coronary angiography (35 normal, 108 coronary patients: 36 single vessel, 36 double vessel and 36 triple vessel disease) were included in this study. The lesions were located of the LAD (77 cases), left circumflex (77 cases) and right coronary arteries (62). The sensitivity and specificity of both radionuclide investigations were evaluated to assess their diagnostic value; the best results were obtained with myocardial scintigraphy (sensitivity 86 p. 100; specificity 100 p. 100); angioscintigraphy had a sensitivity of 71 p. 100 and specificity of 97 p. 100, and conventional exercise stress testing of 42 p. 100 and 70 p. 100 respectively. The sensitivity seemed to increase with the degree of stenosis; although the sensitivity of myocardial scintigraphy increased progressively, that of angioscintigraphy doubled in cases of stenosis 90 p. 100 (stenosis less than 90 p. 100, sensitivity = 37 p. 100; stenosis greater than 90 p. 100, sensitivity = 73 p. 100). The sensitivity of myocardial scintigraphy with respect to the severity of the coronary artery disease was best in cases of right coronary artery stenosis (sensitivity in cases of RCA stenosis = 74 p. 100; sensitivity in LAD stenosis = 58 p. 100; sensitivity in left circumflex stenosis = 43 p. 100). The sensitivity of left ventricular angioscintigraphy was best in LAD stenosis (RCA stenosis = 50 p. 100, LAD stenosis = 64 p. 100, left circumflex stenosis = 36 p. 100). The sensitivity of both investigations was poor in left circumflex artery stenosis even when severely diseased. The sensitivity of both investigations was better in diffuse coronary artery disease: myocardial scintigraphy (single vessel disease: 72 p. 100, double vessel disease: 92 p. 100, triple vessel disease: 94 p. 100), left ventricular angioscintigraphy (61 p. 100, 69 p. 100, and 83 p. 100 respectively). Although the association of these two radioisotopic investigations does not improve diagnostic sensitivity, it does provide more information about the localisation and extension of the coronary artery disease especially in LAD and right coronary artery stenosis. These results suggest that these investigations are complementary in the evaluation of patients with coronary artery disease.(ABSTRACT TRUNCATED AT 400 WORDS)

Coronary Disease↗