Three-year follow-up of the Argentine Randomized Trial of Percutaneous Transluminal Coronary Angioplasty Versus Coronary Artery Bypass Surgery in Multivessel Disease (ERACI).

OBJECTIVES: The purpose of this study was to report the 3-year follow-up results of the ERACI trial (Argentine Randomized Trial of Percutaneous Transluminal Coronary Angioplasty Versus Coronary Artery Bypass Surgery in Multivessel Disease). BACKGROUND: Although coronary angioplasty has been used with increased frequency in patients with multivessel coronary artery disease, its value, compared with bypass graft surgery, has not been established. Thus, controlled, randomized clinical trials such as the ERACI are needed. METHODS: In this trial 127 patients who had multivessel coronary artery disease and clinical indication of myocardial revascularization were randomized to undergo coronary angioplasty (n = 63) or bypass surgery (n = 64). The primary end point of this study was event-free survival (survival with freedom from myocardial infarction, angina and new revascularization procedures) for both groups of patients at 1, 3 and 5 years of follow-up. RESULTS: Freedom from combined cardiac events (death, Q-wave myocardial infarction, angina and repeat revascularization procedures) was significantly greater for the bypass surgery group than the coronary angioplasty group (77% vs. 47%; p < 0.001). There were no differences in overall (4.7% vs. 9.5%; p = 0.5) and cardiac (4.7% vs. 4.7%; p = 1) mortality or in the frequency of myocardial infarction (7.8% vs. 7.8%; p = 0.8) between the two groups. However, patients who had bypass surgery were more frequently free of angina (79% vs. 57%; p < 0.001) and required fewer additional reinterventions (6.3% vs. 37%; p < 0.001) than patients who had coronary angioplasty. CONCLUSIONS: 1) Freedom from combined cardiac events at 3-year follow-up was greater in patients who had bypass surgery than in those who had coronary angioplasty. 2) The coronary angioplasty group had a higher incidence of recurrence of angina and the need for repeat revascularization procedures. 3) Cumulative cost at 3-year follow-up was greater for the bypass surgery group than for the coronary angioplasty group.

Argentine randomized trial of percutaneous transluminal coronary angioplasty versus coronary artery bypass surgery in multivessel disease (ERACI): in-hospital results and 1-year follow-up. ERACI Group.

OBJECTIVES: This study was designed to compare freedom from combined cardiac events (death, angina, myocardial infarction) at 1-, 3- and 5-year follow-up in patients with multivessel disease randomized to either percutaneous transluminal coronary angioplasty or coronary artery bypass graft surgery. BACKGROUND: Percutaneous transluminal coronary angioplasty has been an effective approach in patients with coronary artery disease, but its role in patients with multivessel coronary artery disease is still controversial. METHODS: One-hundred twenty-seven patients with multivessel disease and lesions suitable for either form of therapy were randomized to either coronary artery bypass grafting (n = 64) or coronary angioplasty (n = 63). In this study we report the immediate results and freedom from combined cardiac events at 1-year follow-up. RESULTS: Demographic, clinical and angiographic characteristics were similar in both groups. There were no differences in in-hospital deaths, frequency of periprocedure myocardial infarction or need for emergency revascularization procedures between the two groups. At 1-year follow-up, there were no differences in mortality or in the incidence of myocardial infarction between the groups. However, patients treated with coronary artery bypass grafting were more frequently free of angina, reinterventions and combined cardiac events than were patients treated with coronary angioplasty (83.5% vs. 63.7%, p < 0.005). In-hospital cost and cumulative cost at 1-year follow-up were greater for the coronary artery bypass grafting than for the coronary angioplasty group. CONCLUSIONS: No significant differences were found in major in-hospital complications between patients treated with coronary artery bypass grafting or coronary angioplasty. Although at 1-year follow-up there were no differences in survival and freedom from myocardial infarction, patients in the coronary artery bypass grafting group were more frequently free from angina, reinterventions and combined events than were patients in the coronary angioplasty group.

Amrinone stimulation test: ability to predict improvement in left ventricular ejection fraction after coronary bypass surgery in patients with poor baseline left ventricular function.

OBJECTIVES: This study sought to determine whether the response to amrinone in patients with severe baseline left ventricular dysfunction can predict improvement in left ventricular ejection fraction after coronary artery bypass graft surgery. BACKGROUND: Previous studies have suggested that the inotropic response to dobutamine can identify viable myocardium in the setting of chronic coronary disease and left ventricular dysfunction. However, increased oxygen demand stimulated by dobutamine can lead to superimposition of ischemia on the hibernating state, potentially confounding interpretation of results. Amrinone is an inotropic agent that does not critically augment myocardial oxygen demand and may be useful for identification of hibernating myocardium in the chronically ischemic state. METHODS: Forty-four consecutive patients with coronary artery disease and left ventricular ejection fraction < 40% referred for coronary artery bypass graft surgery underwent amrinone stimulation (1 mg/kg body weight). Left ventricular ejection fraction was determined before amrinone stimulation, 20 min after infusion and 21 days after bypass surgery. RESULTS: Baseline ejection fraction was 28 +/- 7% (mean +/- SD). Ejection fraction increased to 35 +/- 5% after amrinone stimulation (p < 0.0001) and to 33 +/- 6% after bypass surgery (p < 0.0001). Postbypass ejection fraction was significantly correlated with postamrinone ejection fraction (r = 0.65, p < 0.0001). Furthermore, the change in ejection fraction from baseline to after bypass surgery was highly correlated with the change in ejection fraction after amrinone stimulation (r = 0.75, p < 0.0001). Of 13 patients with an increase in ejection fraction > or = 10% after amrinone, all 13 had an increase of at least 8% and 11 (85%) of 13 had an increase > or = 10% after bypass surgery. In contrast, of 31 patients with an increase in ejection fraction < 10% after amrinone, only 2 (6%) had an increase > or = 10% (p < 0.0001) and 28 (90%) of 31 had an increase < 5% after bypass surgery. CONCLUSIONS: Augmentation of myocardial contraction by amrinone in patients with chronic coronary artery disease and severe baseline left ventricular dysfunction predicts improvement in left ventricular ejection fraction after coronary artery bypass graft surgery.

Myocardial imaging with technetium-99m CPI: initial experience in the human.

The hexakis(isonitrile)technetium(I) analog [99mTc]carbomethoxyisopropyl isonitrile (CPI) has high myocardial uptake and rapid lung and liver clearance in most animal species. To evaluate [99mTc]CPI as a myocardial imaging agent in the human, we evaluated this tracer in three normals and in six patients with coronary artery disease (CAD). In normals, [99mTc]CPI cleared quickly from the lungs and accumulated in the liver and heart. The liver activity peaked at 10-15 min and cleared through the hepatobiliary system. Planar images were of excellent technical quality with high myocardial to background ratios as early as 10 min after injection. Myocardial activity fell gradually to 76.1 +/- 2.9 (s.d.)% of initial activity by 60 min after injection. In six patients with CAD, myocardial defects were present on planar images up to 2 hr after exercise and injection. In one out of six patients, the defect was not seen 3 hr after injection. In five of the six patients, normal perfusion patterns were observed 1 hr after reinjection of CPI at rest (4 hr after the initial injection). In one patient who developed spontaneous angina prior to reinjection, the perfusion defects persisted. The repeat study 3 days later with injection of [99mTc]CPI at rest was normal. Technetium-99m CPI appears to have excellent physical and biologic properties for use in association with myocardial imaging with exercise.

Usefulness of radionuclide ventriculography in assessment of coronary artery spasm.

Provocative tests that permit detection of coronary artery spasm are widely used in patients with ischemic syndromes. To assess the usefulness of radionuclide ventriculography combined with provocative tests for diagnosis of coronary spasm, the left ventricular (LV) response to exercise, hyperventilation and a cold pressor test was determined in 3 groups. Group I included 10 normal subjects; group II, 49 patients with typical effort angina and fixed obstructive coronary artery disease at catheterization; and group III, 19 patients suspected of having vasospastic angina based on clinical and electrocardiographic findings, each of whom had normal coronary angiographic findings. In group I, LV ejection fraction (EF) increased during hyperventilation and exercise testing in 9 of 10 subjects (90%) and failed to decrease 5% in 9 of 10 subjects (90%) during cold testing. In contrast, while 18 of 49 patients (37%) of group II showed LV dysfunction with cold testing and 8% with hyperventilation, all showed abnormal LV function during exercise. Finally, in group III, LVEF increased during exercise, mimicking the response in normal group, while dysfunction was present in 14 of 19 (74%) during hyperventilation and in 17 of 19 (89%) during cold testing. When results of hyperventilation and cold testing were combined, abnormal responses were present in all patients. Thus, radionuclide ventriculography, when performed in association with 3 forms of stress--exercise, hyperventilation and cold testing--allows accurate identification of patients likely to have coronary spasm.

Myocardial perfusion imaging with a new radiotracer, technetium-99m-hexamibi (methoxy isobutyl isonitrile): comparison with thallium-201 imaging.

Technetium-99m-hexamibi (methoxy isobutyl isonitrile) is a Tc-99m-hexakis analog that can be used as a myocardial perfusion imaging agent. This is a report of an initial study that was performed in four institutions to assess the feasibility of Tc-99m-hexamibi myocardial imaging for the detection of coronary artery disease in patients undergoing treadmill stress test. Thirty-three patients referred for evaluation of chest pain had two exercise stress tests, one with Tl-201 and at least 24 hours after, and a second one with Tc-99m-hexamibi. Myocardial planar imaging started 60 minutes after injection at stress of 10-20 mCi of Tc-99m-hexamibi. Because this agent does not redistribute in myocardium after a stress injection, a second injection of 10-20 mCi of Tc-99m-hexamibi was performed with the patient at rest a few days later. Qualitative assessment of both Tl-201 and Tc-99m-hexamibi myocardial distribution was performed in 297 left ventricle segments (three segments of each of three views). There was a good correlation for the presence of normality, scar, or ischemia with the two radiopharmaceuticals, both on a segment by segment (259/297, or 87.2%) and patient-by-patient basis (29/33, or 87.9%). The number of segments found ischemic with Tl-201 and with Tc-99m-hexamibi were nearly equal, as were the number that were normal with one radiopharmaceutical and ischemic by the other. This initial study demonstrates that it is possible to detect stress-induced abnormalities of myocardial perfusion with Tc-99m-hexamibi similar to Tl-201 imaging.

Simultaneous measurement of ventricular function and myocardial perfusion using the technetium-99m isonitriles.

To assess both ventricular function and myocardial perfusion, five normal volunteers, 19 patients with coronary artery disease, and two patients with cardiomyopathy and normal coronary arteries were injected with 20 mCi of Tc-99m isonitrile (either methoxyisobutyl isonitrile or carbomethoxyisopropyl isonitrile) at peak bicycle exercise and again at rest. A standard Tl-201 stress test was performed in all patients at the same level of exercise within one month of the isonitrile study. In all normal subjects, myocardial perfusion was normal at stress levels and the left ventricular ejection fraction increased 5% or more with exercise. In the 19 patients with coronary artery disease, the ejection fraction response to exercise was abnormal in 14 patients. Perfusion images with the Tc-99m isonitriles correlated well with Tl-201 images during exercise and at rest, with 89% concordance in areas of ischemia or infarction and 93% in normal segments. A simultaneous study of myocardial perfusion and ventricular function can be performed using a single Tc-99m labeled myocardial agent. Tc-99m isonitriles, particularly Tc-99m MIBI, result in sufficiently high photon flux that ventricular performance can be studied at peak exercise and again during rest using the first pass method.

[Digital coronary angiography. A new approach in the analysis of the arteriosclerotic plaque]. / Angiografía digital coronaria. Un nuevo enfoque en el análisis de la placa ateroesclerótica.

In order to define the coronary lesions we prospectively performed digital coronary angiographies in 61 patients. The degree of stenosis was measured in 100 lesions by quantitative analysis using densitometric and geometric methods. Two groups of lesions were found by comparing these two methods: Group A, 47 lesions with a poor correspondence in the degree of stenosis between densitometric and geometric analysis (p greater than 0.01; and group B, 53 lesions with a good correspondence. Both groups were correlated with plaque characteristics (unstable or stable), following angiographic criteria. The mean degree of stenosis in all lesions, for densitometric and geometric analysis was 50.04 +/- 21.1% and x 60.66 +/- 22.1% (p less than 0.01), respectively. Unstable plaque was more frequent in group A (80.9%) than in B (17.9%) (p less than 0.0001), and stable plaque was more frequent in B (81.1%) than in A (19.1%) (p less than 0.0001). Less degree of stenosis between A (41.5 +/- 13.2) and B (61.3 +/- 16.05) was found by densitometric analysis (p less than 0.0001) but it was similar by geometric method (60.02 +/- 11.3 in A and 58.6 +/- 14.4 in B) so that the degree of stenosis in unstable plaque was lower by densitometric method. We conclude that densitometric analysis showed poor correlation with geometric analysis in unstable plaques; the difference could be due to the soft component expression of the unstable plaque.

Life-threatening arrhythmias and RV dysfunction after surgical repair of tetralogy of Fallot. Comparison between transventricular and transatrial approaches.

BACKGROUND: Late postoperative arrhythmias and right ventricular dysfunction may occur after classic repair of tetralogy of Fallot. METHODS AND RESULTS: During a mean follow-up of 8.9 years (range, 5 to 14 years), 24-hour ambulatory electrocardiographic studies were done in 107 patients after repair of tetralogy of Fallot. Radionuclide angiography was performed in 97, and 78 patients also underwent postoperative heart catheterization. The patients were divided into two groups: group A consisted of 71 patients aged 2 months to 61 years (mean, 6.8 years) in whom the right ventricular approach was used; group B included 36 patients aged 8 months to 39 years (mean, 7.9 years) whose repair was through the right atrium. A transannular patch was employed in 42 (59.2%) patients in group A and in 23 (63.9%) patients in group B. Eighteen patients were adults (> 18 years old) at the time of surgery: 13 (18.3%) in group A and 5 (13.8%) in group B. During a mean follow-up of 9.7 years, 57 (80.3%) group A patients were in New York Heart Association (NYHA) functional class I. Atrial flutter was present in 3 (4.2%) patients, and 28 (39.4%) had significant ventricular arrhythmias (> or = Lown grade 2). Postoperative heart catheterization showed good hemodynamic results in 36 of 54 group A patients studied (12 of whom had ventricular arrhythmias); moderate-to-severe pulmonary regurgitation was present in 14 (25.9%) patients; only 2 (3.7%) patients had right ventricular hypertension. On electrophysiological study, 8 of 28 (28.6%) patients in group A had inducible sustained ventricular tachycardia. Despite antiarrhythmic therapy, 2 of these patients died suddenly, presumably from ventricular arrhythmias. Two other late deaths in group A were caused by heart failure. During a mean follow-up of 7.2 years, 33 of 36 (91.7%) patients in group B were in NYHA functional class I. Atrial flutter was not found in any patient in this group. Only 1 (2.8%) patient, who had moderate-to-severe pulmonary regurgitation, had significant ventricular arrhythmias (> or = Lown grade 2). Postoperative catheterization showed good hemodynamic results in 20 of 24 patients; 3 (12.5%) had moderate-to-severe pulmonary regurgitation, and 1 (4.2%) patient had right ventricular hypertension. Sustained ventricular tachycardia could not be induced in any of the 5 adult patients who underwent electrophysiological studies. One late death (caused by endocarditis) occurred in group B. CONCLUSIONS: The right atrial approach significantly reduced the risk of life-threatening ventricular arrhythmias after repair of tetralogy of Fallot (P < .001) without increasing the incidence of supraventricular arrhythmias. Right ventricular dysfunction and severe pulmonary regurgitation were also more prevalent (P < .01) when the right ventricular approach was used.

The utilization of Tc-99m-TBI as a myocardial perfusion agent in exercise studies: comparison with Tl-201 thallous chloride and examination of its biodistribution in humans.

Twenty-four patients were studied with both 201Tl-thallous chloride and 99mTc-TBI scintigraphy following exercise. Comparison of the two agents in detecting segmental myocardial ischemia and scar was made in 18 patients with evidence of coronary artery disease on 201Tl-thallous chloride scintigraphy. Agreement between the two studies was observed in 77% (125 of 162) of left ventricular segments, suggesting that 99mTc-TBI can be used as a myocardial perfusion agent. Limitations were related to early high background activity from lungs and liver. The high lung activity and early myocardial redistribution within the 1st hour contributed to the failure of 99mTc-TBI to detect 16 segmental defects seen in the immediate post-exercise thallous chloride scan. Persistently high liver activity additionally affected accurate interpretation in the left ventricular segments close to the diaphragm. Improvement in the accuracy of 99mTc-TBI stress studies might be achieved with tomographic imaging to reduce the problem of background activity or by the development of 99mTc-labeled isonitrile analogues with rapid lung and liver clearance.

[Simultaneous test of ventricular function and myocardial perfusion, during exercise, using a new agent labeled with Tc99m]. / Test simultáneo de función ventricular y perfusión miocárdica, durante el ejercicio, mediante un nuevo agente marcado con Tc99m.

One a tribute of a Tc 99m labeled myocardial agent is the possibility to measure both ventricular function and myocardial perfusion with a single injection. To assess this, normal volunteers, 14 patients with coronary artery disease (CAD) and two suffering from cardiomyopathy with normal coronaries, were injected with 8-10 mci carbomethoxy-isopropyl-isonitrile or 20 mci Rp-30 Tc 99m at peak semi-recumbent bicycle exercise and again at rest. Thirty msec per frame first pass data, and 5 min static anterior, 40(0-) and 70(0-) left anterior oblique images were obtained. Standard Thallium 201 stress test were also done, within one month, and were at the same level of exercise. The left ventricular ejection fraction (EF) increased with exercise (69%-76%) in normal patients. All studies showed normal myocardial perfusion on exercise. In CAD patients the EF increased in some patients who had ischemia. Perfusion images with Tc 99m during exercise and at rest had an identical correlation with Thallium 201. The results support the concept of dual ventricular function and perfusion studies using a single Tc 99m labelled myocardial agent, and suggest that this could become the standard radionuclide stress tests in the future.

Transcoronary sinus administration of autologous bone marrow in patients with chronic refractory stable angina Phase 1.

PURPOSE: Based on our preclinic studies with autologous unfractionated bone marrow (AUBM) via coronary sinus with transitory occlusion, a clinic study in patients with chronic stable angina was designed. The objectives were to evaluate safety, tolerance and feasibility. METHODS AND MATERIALS: A multicenter prospective study with inclusion and exclusion criteria defined by an Independent Clinical Committee was carried out. Fourteen patients underwent transcoronary sinus administration of freshly aspirated and filtered AUBM (60-120 ml). Safety and tolerance were evaluated. Feasibility was evaluated with Seattle Angina Questionnaire (SAQ), Canadian Cardiovascular Society (CCS) angina classification (baseline-Day 180), myocardial perfusion (baseline-Day 90) with independent core laboratory and coronary angiography (baseline and Day 30). RESULTS: There were no changes in the safety and tolerance parameters. Preliminary clinical efficacy at Day 180 disclosed a significant improvement of 38%, evaluated by the SAQ. The CCS angina classification shows that the mean angina class was 3.0+/-0.55 at baseline and improved to 2.0+/-0.00 at Day 180 (P <.001). Semiquantitative radionuclide perfusion imaging (core lab) showed a significant improvement at Day 90 in 13/14 patients, with a mean improvement of 24% at rest (P <.01) and 33% at stress (P <.05). Coronary angiography showed more collateral vessels in 9/14 patients. CONCLUSIONS: We can conclude that AUBM via coronary sinus with transitory occlusion is tolerable and safe. Significant improvement in the myocardial perfusion at Day 90 and in the quality of life at Day 180 was observed.

Correlaciones clinino-angiograficas en el infarto agudo transmural tratado con tromboliticos / Clinico-angiographic correlations in transmural acute myocardial infarction treated with thrombolytic agents

Se analizaron los hallazgos clínico-angiográfico de 37 pacientes con infarto agudo transmural 9IAM) recanalizado por trombolítos dentro de las 6 horas del inicio de lao síntomas. Todos tenían estudio angiográfico post intervención inmediata y tardía (x = 22 días). De acuerdo a los síntomas previos los pacientes se dividieron en dos grupos: A) asintomáticos o con síntomas dentro de los 7 días previos al IAM; B) con síntomas de más de 7 días de evolución. Se correlacionó el grado de obstrucción, la presencia de ulceración y el número de vasos comprometidos. Todos los hallazgos clínicos y angiográficos fueron evaluados independientemente por 4 observadores (doble ciego). En el grupo A), en el estudo inmediato predominaron las obstrucciones severea y en el estudio tardío, las obstrucciones leves y moderadas. En el grupo B), en el estudio inmediato se observaron obstrucciones residuales severas en todos los casos, mientras que en el estudio tardío no se registraron cambios significativos en el grado de obstrucción. en consecuencia, se observó: 1) significativa reducción del grado de obstrucción entre el estudio precoz y tardío en los pacientes del grupo A; 2) en el estudio tardío diferencia significativa de severidad de obstrucción entre el grupo A y B; 3) en los pacientes del grupo A, al presentar obstrucción entre el grupo A y B; 3) en los pacientes del grupo A, al no presentar obstrucción residual severa en forma tardía, la terapéutica trombolítica podría ser el único tratamiento

Test simultaneo de function ventricular y perfusion miocardica durante el ejercicio mediante un nuevo agente marcado con Tc99m / Simultaneous test of ventricular function and myocardial perfusion during exercise with a anew agent labelled with Tc99m

Utilizar un radiocompuesto con Tc99m para estudiar la perfusión miocárdica, permite determinar la función ventricular en la misma inyección, mediante la técnica de primer pasaje. Fueron estudiados 4 voluntarios normales, 14 pacientes con angina de esfuerzo y 2 portadores de miocardiopatía con coronarias normales. Todos fueron inyectados con 8-10mci de Tc99 carbometoxi-isopropil isonitrilo (CPI-Tc99m), o con 20mci de Tc99m-Nen-30, en el pico del ejercicio ergométrico y luego en reposo. Fue registrado el primer pasage del bolo radioactivo en imágenes de 30ms/frame. Se adquirieron luego a los 60 min las imágenes de perfusión correspondientes al esfuerzo, en las proyecriones anterior, OAI 45- y OAI 70-. Todos los pacietnes tenían realizado un estudio de perfusión de ejercicio con Talio 201 con similares niveles de esfuerzo. la fracción de eyección (FE) de ejercicio incrementó 69-76% en los normales; la perfusión miocárdica (PM) fue normal en todos ellos. En losportadores de miocardiopatía con coronarias normales, se observó disminución de la FE y la perfusión miocárdica con CPI-Tc99m. En los pacientes isquémicos la perfusión fue anormal en los 14 pacientes y la correlación con el Talio 201 fue excelente. Durante el ejercicio la FE incrementó en 4/14, disminuyó en 6/14 y permaneció sin cambios en 4/14. Estos resultados sugieren la posibilidad de utilizar el test simultáneo de perfusión y función ventricular con un solo ejercicio y radiocompuesto. La información de estos dos estudios mejoraría considerablemente la eficiencia del método, el cual podría convertirse en el test-radioisotópico estándar en el futuro

Angiografía digital coronaria: un nuevo enfoque en el análisis de la placa ateroesclerótica / Digital coronary angiography: a new approach in the analysis of the arteriosclerotic plaque

Se efectuó en forma prospectiva y consecutiva un análisis delgrado de obstrucción coronaria mediante angiografía digital en 61 pacientes, 12 de sexo feminino y 49 masculino, con una edad promedio de 57,8 ñ 11,2 años, presentando 28 de ellos cuadro clínico de angor estable y los 33 restantes angor inestable. se analizaron 125 lesiones en las cuales se realizó cuantificación digital de la obstrucción simultáneamente por: a) análisis geométrico, b) ánalisis videodensitométrico, descartándose 25 lesiones por ser consideradas inadecuadas para uno o ambos métodos o por presentar obstruciones totales. Para el análisis geométrico se midió automaticámente la distancia en pixels borde a borde en un segmento sano y uno enfermo, obteniéndose el gradod e obstrucción a partir de la comparación de a sdistintas densidades de grises analizada en cada ROI. Cuando entre ambos métodos hubo diferencia mayor del 10% se definió la lesión como placa discordante (Grupo A), mientras que el resto fue considerado concordante (Grupo B), correlacionando el grado de obstrucción con el tipo de placa activa o inestable e inactiva o estable de acuerdo a la clasificación angiográfica de Ambrose. El grado de obstrucción por análisis geométrico fue 60,66 ñ 22.1% y 50,05 ñ 21,1% por diedensitometría (p < 0,01) en el Grupo A, 60,02 ñ 11,3% y 41.5 ñ 13,2% (p < 0,01) y en el grupo B, 58,6 ñ 14.4% y 61,3 ñ 16,5% (NS), respectivamente. En el grupo A (47 lesiones), el tipo de placa fue estable en 9 lesiones (19,1%) e inestable en 38 lesiones (80,9%) (p < 0,001), en el grupo B (53 lesiones) en 43 lesiones (81,1%) fue estable e inestable en las 10 restantes (18,9%) (p<0,001). Se concluye: 1) la cuantificación del grado de obstrucción por videodensitometría mostró significativa divergencia con la cuantificación geométrica en las placas inestables; 2) la diferencia del grado de obstrucción, entre el análisis geométrico y la videodensitometría, podría obedecer al componente blando de la obstrucción coronaria, 3) la videodensiometría podría convertirse en el método de elección para cuantificar el grado de obstrucción en el paciente inestable