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1.
Cathet Cardiovasc Diagn ; 42(4): 367-73, 1997 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-9408611

RESUMEN

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%.


Asunto(s)
Vasos Coronarios/cirugía , Isquemia Miocárdica/cirugía , Inhibidores de Agregación Plaquetaria/uso terapéutico , Stents , Ticlopidina/uso terapéutico , Adulto , Anciano , Anciano de 80 o más Años , Anticoagulantes/uso terapéutico , Angiografía Coronaria , Vasos Coronarios/efectos de los fármacos , Femenino , Estudios de Seguimiento , Heparina/uso terapéutico , Humanos , Masculino , Persona de Mediana Edad , Isquemia Miocárdica/diagnóstico por imagen , Isquemia Miocárdica/tratamiento farmacológico , Complicaciones Posoperatorias/tratamiento farmacológico , Complicaciones Posoperatorias/etiología , Complicaciones Posoperatorias/mortalidad , Estudios Prospectivos , Stents/efectos adversos , Tasa de Supervivencia , Trombosis/diagnóstico por imagen , Trombosis/tratamiento farmacológico , Trombosis/etiología
2.
Arch Mal Coeur Vaiss ; 87(11): 1431-7, 1994 Nov.
Artículo en Francés | MEDLINE | ID: mdl-7771889

RESUMEN

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.


Asunto(s)
Angioplastia Coronaria con Balón , Enfermedad Coronaria/terapia , Oclusión de Injerto Vascular/prevención & control , Stents , Ticlopidina/uso terapéutico , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Enfermedad Coronaria/cirugía , Trombosis Coronaria/etiología , Trombosis Coronaria/prevención & control , Vasos Coronarios/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores de Riesgo , Factores de Tiempo
3.
Arch Mal Coeur Vaiss ; 84(7): 949-56, 1991 Jul.
Artículo en Francés | MEDLINE | ID: mdl-1929714

RESUMEN

The aim of this study was to detect possible atrial electrophysiological abnormalities in patients with unexplained embolic cerebrovascular accidents without overt atrial arrhythmias. This group was compared with normal controls and a group of patients with paroxysmal atrial fibrillation. Sixty-six patients were studied: Group I normal controls (N = 20); Group II patients with CVA (N = 26) and Group III, patients with paroxysmal atrial fibrillation (N = 20). Each group was divided into 2 subgroups according to age (over and under 45 years). The following parameters were taken into consideration: parameters correlated to atrial excitability (effective and functional refractory periods, adaptation of these refractory periods, intraatrial conduction--A1 and A2, S1A1, S2A2 intervals--, index of latent vulnerability); provocative testing by the extrastimulus technique; classical indices of atrioventricular conduction and sinus node function. In subjects over 45 years of age, the effective refractory periods were shorter in Group III (214 +/- 33 ms) and II (214 +/- 32 ms) than in the control Group I (248 +/- 21 ms), p less than 0.01. This difference was not apparent in younger patients. Inadaptation of the refractory periods was demonstrated equally in Groups II and III in all ages whilst the control subjects showed normal adaptation, p less than 0.05. Intraatrial A1 and especially A2 conduction was significantly prolonged in Group III (94.5 +/- 24 ms) and II (87 +/- 14 ms) compared with the control group (69 +/- 8 ms), p less than 0.01, especially in younger subjects.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Fibrilación Atrial/fisiopatología , Trastornos Cerebrovasculares/fisiopatología , Adulto , Anciano , Fibrilación Atrial/complicaciones , Trastornos Cerebrovasculares/etiología , Electrocardiografía Ambulatoria , Electrofisiología , Femenino , Sistema de Conducción Cardíaco/fisiopatología , Humanos , Masculino , Persona de Mediana Edad
4.
Arch Mal Coeur Vaiss ; 84(3): 311-8, 1991 Mar.
Artículo en Francés | MEDLINE | ID: mdl-2048916

RESUMEN

This study reviewed the clinical histories of 148 coronary patients aged 34 +/- 5 years (20-40 years) documented in the same cardiology unit. Myocardial infarction was the presenting condition in 114 patients (77%): inaugural 65%, with prodrome 7%, asymptomatic 4%. The presentation was angina pectoris in 32 patients (22%): effort angina 15%, unstable angina 7%. Two patients had other symptoms (1%). The coronary lesions were significant (greater than 50%) in 112 patients (77%) which included 41% single vessel diseases and 36% multiple vessel diseases. The coronary lesions were insignificant in 10 patients (7%) and absent in 21 (15%) (33% under and 11% over 30 years of age). After an average follow-up of 48 months (range 1 to 10 years), 20 of the 32 patients presenting with angina developed myocardial infarction and 6 had episodes of unstable angina (65% in the first year following diagnosis). Six patients had no serious coronary events, but thereafter, 3 died. Fifteen patients (47%) are asymptomatic (including 8 after coronary bypass surgery). Ten patients are symptomatic. Of the 114 patients with inaugural myocardial infarction, 3 have died, 67 (58%) are symptomatic; the average number of risk factors per patient was related to age and to the degree of coronary artery disease. The left ventricular ejection fraction was significantly higher in asymptomatic patients than in those who had presented a coronary event after myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Enfermedad Coronaria/fisiopatología , Análisis Actuarial , Adulto , Factores de Edad , Angiografía Coronaria , Enfermedad Coronaria/diagnóstico , Enfermedad Coronaria/epidemiología , Enfermedad Coronaria/mortalidad , Estudios de Seguimiento , Humanos , Masculino , Pronóstico , Estudios Retrospectivos , Factores de Riesgo , Volumen Sistólico
5.
Arch Mal Coeur Vaiss ; 83(12): 1817-21, 1990 Nov.
Artículo en Francés | MEDLINE | ID: mdl-2125192

RESUMEN

In order to establish which indices of early diastolic function obtained by Doppler echocardiography and the time/activity curve of 99mTc radionuclide angiography are the most useful clinically, the two investigations were performed in 41 subjects aged 52 +/- 15 years. The maximum velocity of LV filling and mitral E wave provided the best correlation (r = 0.48); the Doppler A wave did not correlate with its scintigraphic homologue. The correlations with the morphological data (mass, thickness/radius ratio) were better with radionuclide angiography. Variance analysis of E and maximum velocity of filling showed that gamma angiography was significantly more accurate (FE LVF greater than 10 p = 10 - 4); on the other hand, the A wave best illustrated the transfer of filling to late diastole. In conclusion, left ventricular filling may be assessed clinically by Doppler echocardiography; the greater accuracy of the radionuclide measurements with respect to left ventricular volumes makes this a more appropriate method when quantitative information is required.


Asunto(s)
Ecocardiografía Doppler , Ventriculografía con Radionúclidos , Función Ventricular Izquierda/fisiología , Adulto , Anciano , Análisis de Varianza , Diástole , Humanos , Persona de Mediana Edad
6.
Arch Mal Coeur Vaiss ; 83(8): 1143-7, 1990 Jul.
Artículo en Francés | MEDLINE | ID: mdl-2124451

RESUMEN

Because of discrepancy in interpretation of early diastolic filling indices in normal subjects and hypertensive, we studied the correlations between age and radionuclide angiographic peak filling rate (PFR), doppler echocardiographic early E and late A waves, left ventricular mass (LVM), blood pressure (BP) and ejection fraction (EF) in cautiously screened 30 untreated hypertensive and 30 age paired normal subjects (mean of age 52 +/- 17 ranging from 34 to 78 years). No patient had gross obesity nor coronary artery disease. Univariate analysis revealed strong correlations between LV filling and age in normal (r = -0.82 p less than 0.0001) and hypertensive (r = -0.61 p less than 0.001), with a very significant difference in y intercepts (t = 0.61 p = 10(-6)). LVM correlated poorly with age (r = 0.35 p less than 0.05) but with none of the LV filling indexes. BP correlated with PFR (r = 0.33 p less than 0.05) and A wave (r = 0.44 p less than 0.02) in hypertensive only. After multivariate analysis, significant dependencies of PFR, age, LV mass were more accurate if BP was in a higher range. The variability of the values of LV filling indexes was wider in hypertensive than in normotensive. Normotensive aging and hypertension have similar effects on the cardiovascular system. In the most aged people even without apparent cardiac disease, it is not possible to identify the specific effects of hypertension on diastolic function.


Asunto(s)
Envejecimiento/fisiología , Hipertensión/fisiopatología , Volumen Sistólico , Adulto , Anciano , Presión Sanguínea , Diástole , Ecocardiografía Doppler , Corazón/diagnóstico por imagen , Ventrículos Cardíacos/patología , Humanos , Persona de Mediana Edad , Análisis Multivariante , Cintigrafía
7.
Arch Mal Coeur Vaiss ; 82(7): 1109-14, 1989 Jul.
Artículo en Francés | MEDLINE | ID: mdl-2510638

RESUMEN

This study was performed to evaluate the incidence ant the practical consequences of left ventricular diastolic dysfunction in hypertensive. In 70 mild to moderate hypertensive subjects group [systolic 161 +/- 16 and diastolic blood pressure 104 +/- 9 mmHg 18 women, 52 men, 51 +/- 7 years old] and in a 15 normal subjects control group, the peak filling rate (PFR) and the time to peak filling rate (TPFR) were measured with the time/activity curve of the rest equilibrium blood pool scintigraphy. The ejection fraction and the stress test were normal in all patients [EF 0.66 +/- 0.05, ranging from 0.59 to 0.88]. The PFR was not significantly different in the hypertensive group but 59/70 patients [84 p. 100] showed an individual value lower than the theoretical age and heart rate expected value. The TPFR was not significantly different (183 +/- 33 ms-vs 180, p = ns). In a Holter-defined sub-group of patients (n = 22) exhibiting a high prevalence of supra-ventricular premature beats or a paroxysmal atrial fibrillation, the PFR was significantly slower than in the total hypertensive group [1.92 +/- 0.33 EDV/s-1, p = 0.02]. Early indices of diastolic function give some instantaneous information on left ventricular filling. Determining the exact significance of individual values of PFR and TPFR requires a better knowledge of physiologic and pathologic determinants of LV filling.


Asunto(s)
Hipertensión/diagnóstico por imagen , Contracción Miocárdica , Adulto , Anciano , Gasto Cardíaco , Diástole , Femenino , Ventrículos Cardíacos , Humanos , Hipertensión/fisiopatología , Masculino , Persona de Mediana Edad , Cintigrafía
8.
Ann Cardiol Angeiol (Paris) ; 38(1): 43-6, 1989 Jan.
Artículo en Francés | MEDLINE | ID: mdl-2648966

RESUMEN

To increase our understanding of the interaction between anti-hypertensive drug therapy and left ventricular filling, 23 hypertensive patients (DBP 100 +/- 4 mmHg) had their myocardial mass measured and underwent gamma-angiography (determination of maximum volume of filling, MVF, end-diastolic volume/s-1, and the maximum time for filling, MTF, ms) before and after therapy with propranolol (100 mg/d), captopril (50 mg/d), nitrendipine (28 mg/day) or xipamide (20 mg/d). Blood pressure was recorded in the four treatment groups, and myocardial mass regressed only in those treated with propranolol or nitrendipine. Only the latter drug acts simultaneously on MVF (2.19 +/- 0.22 vs 2.47 +/- 0.43 EDV/s -1) and MTF (221 +/- 21 vs 192 +/- 20 ms) significantly (p less than 0.05). Xipamide only improved MTF (228 +/- 28 vs 209 +/- 20 ms; p less than 0.05). These data compared to those of the literature demonstrate the variability in the antihypertensive effects on ventricular filling, while its improvement may be proposed as a usual objective in treatment of hypertensive disease.


Asunto(s)
Antihipertensivos/farmacología , Hipertensión/tratamiento farmacológico , Contracción Miocárdica/efectos de los fármacos , Adulto , Femenino , Ventrículos Cardíacos , Humanos , Masculino , Persona de Mediana Edad
9.
Arch Mal Coeur Vaiss ; 81(3): 325-30, 1988 Mar.
Artículo en Francés | MEDLINE | ID: mdl-3134870

RESUMEN

Five men (mean age 39 years) were followed up for 6 to 60 months for tricuspid valve regurgitation caused by a front-to-back injury (in a car in four cases, in an aircraft in one case). The time elapsed between the accident and the signal symptoms varied from 28 days to 20 years. The condition was diagnosed on clinical data (stage 2) and on the results of echocardiography and cardiac catheterization. Four patients were operated upon and provided with a bioprosthetic valve. The post-operative period was marked by resolutive atrioventricular block in one case and inferior myocardial infarction in one case. Four points ought to be highlighted: 1. The long-term development of dilatation of the annulus, cicatricial fibrosis or altered left ventricular contractility; 2. The usefulness of pulsed Doppler echocardiography for the diagnosis and surgical indications (quantification of the regurgitation, right ventricular kinetics); 3. The adaptation of treatment to the lesion: repair whenever possible, or annuloplasty, or bioprosthetic valve replacement (mechanical valves must be excluded); 4. The time for surgery is difficult to determine in view of the asymptomatic period, which may be very long. The decision to operate is based on clinical, echocardiographic, haemodynamic and dromotropic (complete arrhythmia due to atrial fibrillation) data. This decision must be reached before right ventricular myocardial deterioration sets in.


Asunto(s)
Traumatismos Torácicos/complicaciones , Insuficiencia de la Válvula Tricúspide/etiología , Heridas no Penetrantes/complicaciones , Accidentes de Aviación , Accidentes de Tránsito , Adulto , Anciano , Ecocardiografía , Prótesis Valvulares Cardíacas , Hemodinámica , Humanos , Masculino , Persona de Mediana Edad , Factores de Tiempo , Insuficiencia de la Válvula Tricúspide/diagnóstico , Insuficiencia de la Válvula Tricúspide/cirugía
10.
Arch Mal Coeur Vaiss ; 80(13): 1921-5, 1987 Dec.
Artículo en Francés | MEDLINE | ID: mdl-3130009

RESUMEN

An exceptional case of triple intracardiac thrombosis (right atrium and right and left ventricles) is reported. The 21-year old male patient without significant previous history was admitted in a state of acute circulatory failure, with blood pressure 80/45 mmHg and a left ventricular end-diastolic diameter of 74 mm. Echocardiography showed dilated cardiomyopathy with low output pattern and demonstrated the presence of three large intracavitary thrombi: the first one was attached to the lateral wall of the right ventricle and occupied most of the apex; the second one, with multiple lobes, was located in the left ventricle, and the third thrombus was appended to the roof of the right atrium. The severity of the patient's condition made it necessary to implant an artificial heart (Jarvik's heart), and this was followed, 15 days later, by cardiac transplantation. Pathological examination of the explanted heart confirmed the presence of the three thrombi and of a cardiomyopathy of undetermined origin. This is first case of this type published so far.


Asunto(s)
Cardiomiopatía Dilatada/complicaciones , Ecocardiografía , Cardiopatías/diagnóstico , Trombosis/diagnóstico , Enfermedad Aguda , Adulto , Electrocardiografía , Atrios Cardíacos , Cardiopatías/etiología , Insuficiencia Cardíaca/etiología , Trasplante de Corazón , Ventrículos Cardíacos , Corazón Artificial , Humanos , Periodo Intraoperatorio , Masculino , Trombosis/etiología
11.
Ann Cardiol Angeiol (Paris) ; 36(9): 467-72, 1987 Nov.
Artículo en Francés | MEDLINE | ID: mdl-3122628

RESUMEN

The effects of a nitroglycerin transdermal therapeutic system (TTS NG 10 mg/24 h) 24 hours after application were evaluated by exercise left ventricular radionuclide cineangiography. 20 patients with ischemic heart disease were included in a double-blind, within patient, acute study comparing TTS NG to placebo. Were measured: exercise-test parameters and global (EF) and regional (rEF) ejection fractions at rest and during exercise. At maximum load, the double product rose from 18,680 +/- 4,118 with placebo to 21,538 +/- 3,988 with TTs NG (p less than 0.01) and ST-segment depression at same load decreased from 2.6 +/- 0.7 mm with placebo to 1.0 +/- 0.7 mm with TTS NG (p less than 0.001). Exercise EF increased from 0.57 +/- 0.15 with placebo to 0.63 +/- 0.12 with TTS NG (p less than 0.001) and was higher at exercise than at rest. Two hypokinetic territories improved during exercise with TTS NG: basal rEF increased to 0.45 +/- 0.07 with TTS NG versus 0.31 +/- 0.13 with placebo (p less than 0.01); anteroseptal rEF increased to 0.49 +/- 0.14 versus 0.43 +/- 0.14 with placebo (p 0.05); no significant improvement was observed in anterolateral and inferior territories were previous myocardial infarction occurred predominantly. These data demonstrate the 24 hours efficacy of this new galenic form of TTS NG in ischemic heart disease on exercise test parameters. TTS NG improving predominantly regional kinetics of ischemic but non infarcted territories and thus improving EF at exercise.


Asunto(s)
Enfermedad Coronaria/tratamiento farmacológico , Nitroglicerina/administración & dosificación , Administración Cutánea , Esquema de Medicación , Evaluación de Medicamentos , Prueba de Esfuerzo , Femenino , Corazón/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Nitroglicerina/uso terapéutico , Cintigrafía
12.
Ann Med Interne (Paris) ; 138(7): 506-11, 1987.
Artículo en Francés | MEDLINE | ID: mdl-3439673

RESUMEN

A retrospective study of 40 non-lethal myocardial infarctions occurring during physical exercise (average age 38 years) compared with 100 controls (average age 41 years) showed that the coronary artery disease which was identical after 40 years of age, differed in the youngest age subgroups. Juvenile exercise-induced infarction (N = 20) was characterised by a high incidence of normal coronary vessels (N = 8 compared with 6 in 39 controls of comparable age). The cardiovascular risk factors were qualitatively and quantitatively the same with a high incidence of smoking (85 to 95 p. 100) in the juvenile groups, especially with normal coronary arteries. Premonitory chest pain was sporadic and atypical before the age of 40 but was typical and recurrent in half of the older men, though generally unrecognised. Analysis of the circumstances surrounding infarction showed that in 90 p. 100 of cases (and in all juvenile cases) there were several factors in common related to the conditions under which the exercise was performed: external conditions (particularly the weather) or individual conditions (fatigue, dietary error, etc.) which probably played a contributory role. These observations suggest that a preventive strategy may be possible based on an anti-smoking campaign, on the identification of high risk subjects and on the adoption of adequate conditions of surveillance and performance of physical training.


Asunto(s)
Personal Militar , Infarto del Miocardio/prevención & control , Esfuerzo Físico , Deportes , Adulto , Enfermedad Coronaria/diagnóstico por imagen , Enfermedad Coronaria/patología , Humanos , Hipercolesterolemia/complicaciones , Masculino , Persona de Mediana Edad , Infarto del Miocardio/etiología , Infarto del Miocardio/genética , Radiografía , Estudios Retrospectivos , Factores de Riesgo , Fumar/efectos adversos
13.
Arch Mal Coeur Vaiss ; 79(12): 1720-4, 1986 Nov.
Artículo en Francés | MEDLINE | ID: mdl-2952097

RESUMEN

Research into improving the efficacy of laser in the vaporisation of atheromatous plaques has led to the study of their modes of emission and to attempts at changing the natural absorption properties of the target lesion. This was achieved in vitro by incubation with solutions of derived haematoporphyrin and in vivo by oral administration of therapeutic doses of tetracycline. The selective nature of the coloration produced having been proved, the use of appropriate lasers allowed reduction of 50 to 100 p. 100 of the emitted energy; the exploitation of the fluorescent properties of tetracycline, investigated by laser spectrofluoroscopy in this study, has led to the concept of in situ photodiagnosis of the plaque. These results may open up a new field of research into unknown photobiological characteristics radically different to the thermic energy used at present.


Asunto(s)
Enfermedad de la Arteria Coronaria/tratamiento farmacológico , Fotoquimioterapia , Derivado de la Hematoporfirina , Hematoporfirinas/uso terapéutico , Humanos , Técnicas In Vitro , Terapia por Láser , Tetraciclina/uso terapéutico
14.
Ann Cardiol Angeiol (Paris) ; 35(6): 351-4, 1986 Jun.
Artículo en Francés | MEDLINE | ID: mdl-3777824

RESUMEN

38 observations of myocardial infarction (M.I.) (group A), remarkable by their occurrence immediately (31 cases) or with a delay (less than 12 hours, 7 cases) after the onset of chest pain and/or lipothymia during (30 cases) or a the end (7 cases) of a non unusual physical effort, have been documented with a 60 items questionnaire for the analysis of exercise, mesologic and personal data. Group A comprised men averaging 37 +/- 8 years, with extreme at 24-54 (less than 40 years: n = 21, m = 30, 5 +/- 3.5 years), divided into high-level athletes (n = 15), very well (n = 12) or moderately (n = 7) trained, and sedentary (n = 4). This group was compared to a historical population of 105 men suffering from a M.I. non preceded by exertion (group B), average age 41 +/- 9, extreme at 19-54 years, with a comparable social status (sports adepts: 26 per cent). The analysis of the responses in group A discloses in order: time of onset of the M.I. (69 per cent before 9 hours), the need for physical performance (45%), heat discomfort (31%). It is endurance work 19 times (50%). Groups A and B are undifferentiated (0.8 less than chi 2 less than 2, p = N,5) concerning the number of risk factors (2.18 +/- 0.98 and 2.42 +/- 1.18), the preceding angor on exertion (24 or 63% and 59 or 56%), the topography of the M.I. (lower 58 and 59),the incidence of complications (extension, left ventricular failure, arrhythmias) in the acute phase (24 and 30%).(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Personal Militar , Infarto del Miocardio/etiología , Deportes , Adulto , Humanos , Masculino , Persona de Mediana Edad , Riesgo
15.
Arch Mal Coeur Vaiss ; 78(12): 1799-804, 1985 Nov.
Artículo en Francés | MEDLINE | ID: mdl-3936427

RESUMEN

The aim of this study was to evaluate the thermal diffusion of a pulsed laser beam in atheroma and to obtain in vitro vaporisation of the plaque without causing arterial wall lesions. A computerised mathematical model integrated 4 parameters: reflectivity, thermal conduction, the absorption factor and coefficient of diffusion. The thermal diffusion was shown to be dependent on the time constant and the temperature of vaporisation may be best attained with a short burst (200 ns) with a high peak power (6000 w). The experimentation was performed on fresh debris and segments of epicardial coronary arteries which were exposed to a pulsed laser beam with a frequency of 1000 Hz in bursts of 200 ns at wave lengths of 1060 and 532 nm. The results were evaluated by microscopic examination of transverse sections perpendicular to the lumen of the artery. Effective vaporisation of atheroma was observed with weak mean dissipating powers (0.4 w) about 10 times weaker than with continuous node emission; examination of the underlying arterial wall showed no thermal or mechanical damage.


Asunto(s)
Enfermedad Coronaria/radioterapia , Terapia por Láser , Computadores , Humanos , Modelos Teóricos
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