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Biomedical subjects

P Barragan

Publications and source records attributed to P Barragan.

At least 19 recordsLinked to original sources
PubMed2000

Elastic recoil of coronary stents: a comparative analysis.

Minimum elastic recoil (ER) has became an essential feature of new coronary stents when deployed in artheromatous lesions of various morphologies. The ER of coronary stent might be an important component of 6-month restenosis rate by minimizing the luminal loss. We evaluated the intrinsic ER of 23 coronary stents with a mechanical test bench. The amount of ER for one size of stent (3.0 mm) was quantified using a 3D optical contactless machine (Smartscope MVP, Rochester, NY). The stents were expanded on their own balloon for the precrimped stents; the uncrimped stents were expended using identical 3.0-mm balloons. Two types of measurements were done without exterior stress and with a 0.2-bar exterior stress, directly on the stent at the end of balloon expansion, immediately after balloon deflation, and then 30 min, 60 min, and 120 min after. ER ranged from 1.54%+/-0.81% (Bestent BES 15) to 16.51%+/-2.89% (Paragon stent) without stress (P<0.01) and from 2.35%+/-1.14% (Bestent BES 15) to 18.34%+/-2.41% (Cook GR2) under 0.2-bar pressure (P<0.0001). Furthermore, there was a significant reduction between the mean result of tubular stents (TS) and coil stents (CS). The results of in vitro mechanical tests may confirm strongly the interest of a minimum ER in the prevention of the 6-month restenosis.

Angioplasty, Balloon, Coronary↗
PubMed2000

Unprotected left main coronary artery stenting: immediate and medium-term outcomes of 140 elective procedures.

OBJECTIVES: We sought to evaluate immediate and late outcomes after stenting for left main coronary artery (LMCA) stenosis. BACKGROUND: Conventional percutaneous transluminal coronary angioplasty (PTCA), for which coronary artery bypass grafting (CABG) has been the gold standard therapy for years, has yielded poor results in unprotected LMCA lesions. The development of coronary stents, together with their dramatic patency improvement provided by new antiplatelet regimens and their validation against restenosis, warrants a reappraisal of angioplasty in LMCA stenosis. METHODS: From January 1993 to September 1998, 140 consecutive unselected patients with unprotected LMCA stenosis underwent elective stenting. Group I included 47 high-CABG-risk patients, and group II included 93 low-CABG-risk patients. Ticlopidine without aspirin was routinely started at least 72 h before the procedure and continued for one month. Patients were reevaluated monthly. A follow-up angiography was requested after six months. RESULTS: The procedure success rate was 100%. One-month mortality was 9% (4/47) in group I and 0% in group II. A follow-up angiography was obtained in 82% of cases, and target lesion revascularization was required in 17.4%. One-year actuarial survival was 89% in the first 29 group I patients and 97.5% in the first 63 group II patients. CONCLUSIONS: Stenting of unprotected LMCA stenosis provided excellent immediate results, particularly in good CABG candidates. Medium-term results were good, with a restenosis rate of 23%, similar to that seen after stenting at other coronary sites. Stenting deserves to be considered a safe and effective alternative to CABG in institutions performing large numbers of PTCAs.

Adult↗
PubMed1999

Radial force of coronary stents: a comparative analysis.

High radial force has become an essential feature of new coronary stents. These stents are expected to exhibit sufficient radial force and minimum radial recoil when deployed in atheromatous lesions of various morphologies. The aim of this study was to compare the radial force of 17 coronary stents in vitro (Anglodynamics, ACS Multilink, AVE Micro II and GFX, Bard XT, Biocompatibles PC, Cook GR II, Cordis Crossflex, Hexacath Freedom, Johnson & Johnson PS 153'PS 154, and Crown, Medtronic Wiktor and BeStent BEL-15, Saint-Come SC 1616, Scimed Nir 7 and 9). Two in vitro mechanical tests were performed to assess the stent radial force. The first test measured the deformation of coronary stents in a V-stand by using a deformation controlled by a dynamometer based on a longitudinal generatrix. The precision was of 1 micron. This comparative test highlighted the appreciable variation in behavior of the range of tested stents in terms of resistance to local compression. The line graphs obtained show a very small (and in some cases nonexistent) purely elastic behavior area in the stents, with this result reflecting a small (<0.4 Newtons) range of forces applied to all stents. Above this value, the stents did not return to their size before compression and the line graph remains approximately linear for a long period. It was therefore possible to distinguish between two families of stents on the basis of the presence or absence of this elastic area. In the second test, the stent was deployed in a 3.0-mm elastic tube and a pressure gradient created between the interior and exterior of the tube. The precision was of 50 microns. A typical line graph of the pressure-diameter relationship was recognizable for a given stent. No difference in behavior between the different coronary stents was noted up to 0.3 x 10(5) Pa; subsequently, after 0.3 x 10(5) Pa, sizable deformation differences were visible between the least resistant stent, the BeStent BEL-15, and the most resistant stent, the Crossflex.

Evaluation Studies as Topic↗
PubMed1999

Clinical experience with a new biocompatible phosphorylcholine-coated coronary stent.

AIMS: The BiodivYsio stent is a new stent coated with phosphorylcholine, a biocompatible molecule designed to reduce the formation of thrombus and potentially the risk of restenosis. The feasibility, safety, and efficacy of elective and urgent implantation of this coated coronary stent were prospectively studied. METHODS AND RESULTS: We studied 224 patients who underwent elective (67%) or bail-out implantation of 303 BiodivYsio stents in 286 lesions. Most lesions (62%) had unfavorable characteristics (type B2 or C) and half of them (50%) had thrombus and/or chronic total occlusion. Clinical follow-up was obtained in all patients at one month and in the first 132 patients at six months. Repeat angiography was undertaken in all patients with recurrent ischemia. Successful stent deployment was achieved in 284 lesions (99.3%). One emergency coronary artery bypass graft (CABG) was required. Angiographic success rate was 98.3% (281/286). There was 1 (0.4%) subacute stent thrombosis associated with Q-wave myocardial infarction and two (0.9%) in-hospital deaths. Reference vessel diameter was 2.82 +/- 0.32 mm. Minimum luminal diameter (MLD) increased from 0.38 +/- 0.25 mm to 2.97 +/- 0.35 mm and diameter stenosis decreased from 83.8 +/- 12.1% to 5.8 +/- 9.7%. Clinical restenosis rate was 6.1% (8/132 patients) at 6-month follow-up. Target vessel revascularization rate at 6-month follow-up was 5.4%. CONCLUSIONS: This initial clinical experience indicates that the implantation of stents coated with phosphorylcholine appears to be safe and efficacious in the treatment of complex coronary lesions and is associated with an extremely low target vessel revascularization rate.

Adult↗
PubMed1997

Early versus late coronary stenting following acute myocardial infarction: results of the STENTIM I Study (French Registry of Stenting in Acute Myocardial Infarction).

This study was undertaken to determine the feasibility and safety of coronary stenting in acute myocardial infarction (AMI). In AMI, primary percutaneous transluminal coronary angioplasty (PTCA) is accepted as the preferred method of reperfusion for patients presenting at highly experienced centres. Until recently, however, stenting has been avoided during AMI because of a potential high risk of thrombosis. This prospective observational study carried out in 20 centres and included 648 consecutive patients who underwent PTCA with stent implantation for AMI. Of these 648 patients, 269 (41.5%, Group 1) were dilated early (< 24 hr) after the onset of the symptoms (75% treated by direct PTCA) and 379 (58.5%, Group 2) were dilated between 24 hr and 14 days after AMI. Combined therapy with ticlopidin and aspirin was used after the procedure. Bailout stenting occurred more often in Group 1 than in Group 2 (17% vs. 9.5%)(P < 0.05). Angiographic successful stenting was similar in both groups of patients (96% vs. 97%). During the hospital follow-up period, stent thrombosis occurred in eight patients (3%) in Group 1 and in six patients (1.6%) in Group 2 (NS). There was 14 deaths (5.2%) in Group 1 and 11 deaths (3.9%) in Group 2 (NS). After multivariate analysis bailout stenting was identified as the sole predictor of stent thrombosis (P < 0.0001). Vascular access-site complications occurred in six patients (1%) with no difference between the two groups. This study indicates that patients who receive a coronary stent in AMI can be managed safely with antiplatelet therapy. Randomized studies are needed to determine the precise indication for coronary stenting as an adjunct to primary PTCA.

Adult↗
PubMed1997

Coronary artery stenting without anticoagulation, aspirin, ultrasound guidance, or high balloon pressure: prospective study of 1,051 consecutive patients.

Between March 1994 and November 1995, 1,212 coronary stents were implanted in 1,051 consecutive patients at our institution with the following protocol: daily pre- and poststenting treatment with ticlopidine 500 mg without aspirin, implantation under angiographic guidance, without ultrasound, with semi-compliant balloons inflated at 10 bars. Stenting was indicated after failure of balloon angioplasty (bail-out, dissection, elastic recoil) in 27% of the patients and considered as elective (de novo, restenosis, chronic occlusion, saphenous vein grafts) in 73% of the cases. During the 30-day follow-up period, stent thrombosis occurred in 11 patients (1.0%) and vascular access-site complications in three patients (0.3%). Thirteen patients (1.1%) died, 10 from previous left ventricular failure, 3 (0.3%) from subacute thrombosis. Multivariate analysis revealed that the size of the last balloon used was associated with subacute stent thrombosis Thus, in nonselected patients, placement of coronary stents may be safely achieved without use of warfarin, post procedural heparin, high balloon pressure, or ultrasound guidance. Antiplatelet therapy with ticlopidine and angiographic guidance result in a stent thrombosis rate of 1% and a vascular complication rate of 0.3%.

Adult↗
PubMed1996

Retrograde left main stenting.

Percutaneous transluminal coronary angioplasty of protected left main coronary artery stenosis is usually performed by an antegrade approach. In this case report, we describe left main coronary artery stenting by a retrograde approach through a saphenous venous graft in a patient in whom the antegrade approach was considered less appropriate due to chronic ostial occlusion.

Aged↗
PubMed1996

[Antiplatelet therapy during coronary endoprosthesis placement].

Coronary stent implantation is today a catheterisation laboratory routine procedure for de novo lesions and less frequently for bail-out situations. Antithrombotic pharmacological regimens based upon coumadin have filed to prevent sub-acute stent thrombosis. The use of new antiplatelet therapy (ticlopidine alone or in association with aspirin) have reduced the sub-acute thrombosis rate to 1%. Routine combining heparin is not useful. The benefit of ultrasound guided stenting or high pressure balloon expansion is not demonstrated in the thrombosis prevention. New pharmacological approaches inducing fibrinogen platelet receptor antagonists (antii GP IIb-IIIa) may extend stent implementations more especially in acute coronary syndromes.

Angioplasty, Balloon, Coronary↗
PubMed1995

[Rotablator and endoprosthesis on the left main coronary trunk].

A 78 year old woman with unstable angina due to significant stenosis of the left main coronary artery and occlusion of the right coronary artery was treated medically for 29 months because of a surgical contraindication. Resistance to drug therapy led to referral for complex angioplasty of the left main, left anterior descending and left circumflex arteries, successively by rotablator and balloon angioplasty. An immediate elastic recoil on the left main coronary artery led to implantation of a Palma-Schatz stent. There were no complications and the patient is asymptomatic twenty months later.

Aged↗
PubMed1994

Ticlopidine and subcutaneous heparin as an alternative regimen following coronary stenting.

Subacute thrombosis of coronary stents may occur up to the end of the first month after their implantation and remains the major problem associated with the technique. A cohort of 238 patients with placement of one or more stents in 244 arteries was monitored for this period. All patients were given 500 mg/day of ticlopidine (started 3 days before) and a push dose of 10,000 IU of heparin during the procedure, then 1,000-1,500 IU/hr for 20 hr. Following removal of the arterial introducer, they were kept on subcutaneous heparin for 1 week and ticlopidine (500 mg/day) for 3-6 months. Nine patients (3.8%) showed evidence of thrombosis at 7 days. The overall thrombosis rate at 30 days was 4.2% (3.5% for elective stents, as compared with 7.9% associated with occlusive dissections). Emergency treatment by further angioplasty (8 cases) and intracoronary thrombolysis (5 cases) was undertaken. Complications were as follows: 5 deaths (2%), 3 MI (1.2%), 2 non-Q MI (1.7%). Three predictive factors for subacute thrombosis were identified: age < 70 (p = 0.00006), unstable angina (p = 0.006) and arterial diameter less than 3 mm (p = 0.043). The peripheral vascular complication rate was 4.6%. This study suggests that preventive treatment with ticlopidine appears to reduce the incidence of subacute thrombosis of stents in patients > 70 years of age. Furthermore, the combination of ticlopidine and heparin facilitates laboratory monitoring after stenting. Stenting is thought to represent definitive treatment in situations where placement for occlusive dissection is the indication.

Adult↗
PubMed1994

[Pilot study of the efficacy of ticlopidine in early patency of coronary endoprostheses].

Subacute thrombosis of coronary stents is the main complication of this technique. The authors studied the outcome of 387 patients and 400 coronary arteries who underwent implantation of 427 stents between December 1989 and February 1994 and followed up one month after the procedure: all patients receive 500 mg of ticlopidine daily from three days before angioplasty throughout the hospital period and continued for at least one month. Anticoagulation with heparin was undertaken by the intravenous route after implantation and relayed with subcutaneous heparin for one week until control coronary angiography performed in the first 300 patients. At one month, 96.9% of patients were free of clinical coronary events. The following major complications were observed: 5 deaths (1.3%), 5 Q wave myocardial infarctions (1.3%); no emergency bypass surgery. The peripheral vascular complication rate was 3.6%. Univariate analysis three risk factors of subacute thrombosis: age (p = 0.0058), arterial diameter of less than 3 mm (p < 0.01) and implantation for occlusive dissection (p = 0.03). Multivariate analysis showed two independent risk factors: age (p = 0.001) and arterial diameter of less than 3 mm (p = 0.01). This pilot study shows a particularly low subacute thrombosis rate in unselected indications with an acceptable level of vascular complications.

Adult↗
PubMed1993

Cardioprotective effect of intracoronary nifedipine during percutaneous transluminal coronary angioplasty. A French double-blind cross-over multicentre study.

The aim of this double-blind, placebo-controlled, cross-over study was to assess the cardioprotective effect of intracoronary nifedipine during percutaneous transluminal coronary angioplasty balloon occlusion. A balloon inflation without drug injection was initially made to ascertain that a shift of the ST segment (> or = 2 mm, 0.08 s after the J point) appeared (inclusion criterion). Two other balloon inflations were preceded by intracoronary injection of either 0.2 mg nifedipine or placebo, distal to the stenosis through the balloon catheter. The evaluation criteria were (1) time to ST segment shift, and (2) maximal amplitude of ST segment shift caused by balloon occlusion. Comparison of the data used an analysis of variance. Sixty-seven patients (mean age 54 +/- 8 years; 54 male, 13 female) were studied; 50 patients had 1-, 16 patients 2- and 1 patient 3-vessel disease. The dilated vessel was the left anterior descending coronary artery (n = 51), the right coronary artery (n = 12) and the left circumflex coronary artery (n = 4). Balloon inflation time was 100 +/- 31 s in the nifedipine group and 93 +/- 29 s in the placebo group. Five patients were excluded (procedure stopped after the first inflation in 1 and ST segment shift < 2 mm during the first inflation in 4). The time to 2-mm ST segment shift was longer in the nifedipine group than in the placebo group (62 +/- 40 s versus 51 +/- 40 s, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Post-traumatic fistula of the left anterior descending coronary artery and left ventricle. Apropos of a new case].

The authors report the case of a 23 year old man who presented with a continuous murmur five years after closed chest trauma. The electrocardiographic and echocardiographic findings indicated previous apical myocardial infarction. The underlying diagnosis was first suggested by continuous wave Doppler which showed systolo-diastolic flow in the septo-apical region directed towards the left ventricle (LV) in diastole. Color Doppler flow studies showed a mosaic pattern opposite a dilated left anterior descending (LAD) artery. These signs of LAD-LV fistula with a single orific were confirmed at coronary arteriography. The patient's previous history was in favour of a traumatic etiology. In the absence of left ventricular failure and myocardial ischaemia by coronary steal, surgery was deferred; Doppler echocardiography would seem to be a good method of following up the fistula and its consequences on left ventricular function. A traumatic left coronary to left ventricular fistula is an extremely rare condition and merits publication. The authors review the literature and describe the physiopathology, diagnosis and therapeutic indications of these fistulae.

Adult↗
PubMed1989

[Septal rupture repaired in the acute stage of myocardial infarction. Clinical, hemodynamic and angio-coronarography findings in the evaluation of surgical risk].

Between 1977 and 1987, 27 consecutive patients (16 men, 11 women, mean age 66 years, range 54 to 75 years) with ventricular septal rupture complicating acute myocardial infarction underwent surgical repair. The purpose of this retrospective study was to analyse the post-operative mortality factors from clinical, haemodynamic and operative data in all patients and also from coronary angiographic data in 23/27 patients whose haemodynamic status allowed this type of exploration. Seventeen patients (63 p. 100) died during the first post-operative month, 10 survived and were discharged. Factors that influenced the prognosis were: (1) inferiorly-located necrosis associated with a 75 p. 100 mortality rate (9 out of 12 patients), as opposed to 53 p. 100 (8 out of 15 patients) with anterior necrosis; (2) right ventricular dysfunction, observed in 83 p. 100 of patients with inferior necrosis and 53 p. 100 with anterior necrosis, which was responsible for 7 out of 9 deaths in the inferior necrosis subgroup and contributed to 3 out of 8 deaths in the anterior necrosis subgroup; this established a cause-effect relationship between right ventricular function and the overmortality of patients with inferior necrosis; (3) independently of the haemodynamic status, two- and three-vessel lesions (56 p. 100 of all lesions) which had an 84 p. 100 mortality rate as opposed to 40 p. 100 with one-vessel lesions; (4) the presence of a state of shock which was associated with a 78 p. 100 mortality rate as opposed to 55 p. 100 in patients without shock. We conclude that when permitted by the patient's haemodynamic status coronary angiography should be part of the pre-operative evaluation to assess the operative risk and guide the surgical procedure.

Acute Disease↗
PubMed1989

[Atrioventricular block, a complication of radiotherapy of the mediastinum].

Cardiac complications of mediastinal irradiation usually concern the pericardium, the ventricular myocardium and the coronary arteries. We report the case of a 42-year old woman who experienced a syncopal atrioventricular (AV) block 12 years after irradiation of a mediastinal Hodgkin's lymphoma. Electrophysiological recordings showed infranodal conduction disturbances. A review of the literature yielded only 12 cases of syncopal radiation-induced AV block. This case highlights the risk of syncopal AV blocks occurring a long time after mediastinal irradiation and leading to severe damage of the His bundle and its branches. The presence, as in our patient, of an associated right ventricular outflow tract stenosis confirms the importance and severity of radiation-induced cardiac lesions.

Adult↗
PubMed1989

[Percutaneous coronary transluminal angioplasty with extracorporeal circulation: preliminary results].

Percutaneous transluminal coronary angioplasty (PTCA) in patients with low ejection fraction (EF) and/or a large area of remaining viable myocardium served by the target vessel can cause hemodynamic collapse in case of acute closure. We report 11 patients in whom the cardiopulmonary bypass support (CPS) was instituted because of contraindication to surgery (Group I) or unstable angina associated with low EF and/or a large amount of myocardium perfused by the target artery (Group II). Nine were male and 2 female, mean ages of 70, with Canadian angor class I (1), II (1), or IV (9) and EF ranging from 12 to 65% (mean 34%). Thirty were the lesions to dilate; 28 were dilated successfully; in 2 an aortic dilation was also performed. One death occurred after the procedure related to collapse due to hypovolemia; another death occurred 8 months after PTCA because of pulmonary neoplasia. The other 9 patients followed-up at 1 to 8 months (mean 3.9) disclosed Canadian angor class I. The procedure's technique and the related complications are discussed. We conclude that cardiopulmonary bypass support can be used safely in patients refused to surgery and with high risk PTCA; such a procedure may expand the indication of PTCA.

Aged↗
PubMed1988

[Cardiac Doppler in the selection of patients for aortic valvuloplasty. Comparison with data of phonomecanograms].

Between December 1986 and August 1987, 34 patients referred for aortic valvuloplasty, undergo before catheterization an ultrasonocardiography with continuous and pulsed Doppler study and a phonocardiography for 22 of them. They all present functional and physical signs of aortic stenosis. The cardiac Doppler enables a positive diagnosis in all patients, while the phonocardiography recordings fail to recognize a tight aortic stenosis. On the other hand, the Doppler enables a diagnosis of severity well correlated with the catheterization (r = 0.88 for maximum instantaneous gradients) in 30 patients: in four patients, the correlation could not be calculated because of technical problems related to the catheterization (2 patients) or the ultrasonic examination (2 patients). From this study, it results that the cardiac Doppler may perfectly select patients who are to undergo an aortic valvuloplasty, unlike phonocardiography.

Adult↗