First national survey on management strategies in non ST-elevation acute ischaemic syndromes in Argentina. Results of the STRATEG-SIA study.

AIMS: To assess the management strategies applied in non-ST elevation acute ischaemic syndromes in Argentina, the factors influencing the choice of treatment, and their relationship to short- and long-term (1 year) patient outcomes. METHODS AND RESULTS: We conducted a 1 month, prospective, population-based survey in 77 hospitals (all over the country). We recruited 492 patients (age 63.9+/-11.7 years, male sex 68.3%, and 59.8% acute ischaemic ECG changes). Subjects were stratified according to the AHCPR classification as: high risk 62.2%, intermediate 25.0% and low 12.8%. At 1 year, the rate of death or myocardial infarction according to risk category and invasive procedures employed were: high risk (angioplasty 5.4% vs coronary artery bypass grafting 12.1% vs medical treatment 17.2%; P=0.001), intermediate risk (angioplasty 5.7% vs coronary artery bypass grafting 12.5% vs medical treatment 4.7%, P=ns), and low risk (angioplasty 10.0% vs coronary artery bypass grafting 15.2% vs medical treatment 1.9%; P<0.001). In the overall population, the 1 year event rate was not significantly different between the invasive and medical treatment groups (11.5% vs 7.2%, P=0.09). CONCLUSIONS: A routine, unselected invasive approach in non-ST elevation acute ischaemic syndromes in Argentina is associated with no apparent improvement of patients' outcome.

Effect of endothelial dysfunction on regional perfusion in myocardial territories supplied by normal and diseased vessels in patients with coronary artery disease.

BACKGROUND: Endothelium-dependent regulation of coronary tone affects both conduit and resistance coronary arteries. However, little is known about the usefulness of myocardial perfusion imaging in evaluating coronary endothelial function. We evaluated the relation between invasive angiographic measurements of coronary vasomotion in response to intracoronary acetylcholine and the presence of regional perfusion abnormalities assessed by technetium 99m sestamibi imaging. METHODS AND RESULTS: We studied 11 patients (9 men and 2 women) with suspected coronary artery disease (48 +/- 8 years, mean +/- standard deviation). We used quantitative coronary angiography to delineate the vasomotor response to increasing doses of acetylcholine given intracoronary. Regional myocardial perfusion was assessed by planar Tc-99m sestamibi imaging during and after the administration of acetylcholine. In the 11 patients, 23 coronary artery territories were analyzed: 13 were angiographically normal, and 10 showed varying degrees of luminal narrowing. Four (31%) of 13 angiographically normal coronary arteries had a positive vasomotor response to acetylcholine (> or =20% reduction in luminal diameter) that was associated with a regional perfusion defect. Acetylcholine induced a positive vasomotor response, which was also associated with a regional perfusion defect in 1 of 3 coronary arteries with stenoses of intermediate severity (50% to 69%). Likewise, acetylcholine induced a positive vasomotor response in 6 of 7 coronary arteries with significant luminal narrowing (> or =70%), 5 of which showed a corresponding regional perfusion defect. CONCLUSIONS: In patients with coronary artery disease, noninvasive measurements of regional myocardial perfusion by Tc-99m sestamibi correlate well with invasive measurements of coronary endothelial function. These findings may have implications for monitoring the effects of interventions designed to improve endothelial function and microvascular function in patients with coronary artery disease.

Estimation of the ejection fraction in patients with myocardial infarction obtained from the combined index of systolic and diastolic left ventricular function: a new method.

UNLABELLED: The index of myocardial performance combining systolic and diastolic time intervals (Index) is a useful method, already explained in past studies, that offers new values that have not been widely known among clinical cardiologists. The aim of this study is to obtain from this Index a measurement of the ejection fraction (EF), which is a very well-known value. The study involved 97 patients with myocardial infarction, 55 of whom were studied retrospectively (group A, aged 46-62 years, 50 men) to obtain and test the formula EF = 60 - (34 x Index). The second group (group B, aged 47-63 years, 40 men) included 42 patients who were evaluated prospectively. The EF obtained was compared with that reached through the use of radionuclide angiography (EF-RNA). The Index was obtained through the use of the formula (a - b)/b, where a is the interval between cessation and onset of the mitral inflow, and b is the ejection time. In group A the EF obtained by the Index (EF-Index) was 37.5% +/-.8%, and the EF-RNA was 37.7% +/- 11% (r = 0.76). In group B the EF-Index was 41.6% +/- 7%, and the EF-RNA was 41.2% +/- 10% (r = 0. 75). CONCLUSION: Through the new formula described here it is possible to obtain a reliable measurement of the EF in patients with myocardial infarction, a well-known and extremely useful value, especially for those patients with poor acoustic windows.

Early treatment with low-dose enalapril after acute myocardial infarction: an equilibrium radionuclide angiographic study. Enalapril despues del Infarto (EDI) Trial Investigators.

BACKGROUND: To further elucidate the mechanisms involved in the treatment of acute myocardial infarction (AMI) with angiotensin-converting enzyme inhibitors, we compared the effects on left ventricular volumes of early (< 48 hours) versus late (45 days) administration of a fixed low dose of enalapril (10 mg) in patients with AMI. We also analyzed the changes of left ventricular volumes after withdrawal of the study drug. Reduced dilation of the left ventricle is one of the beneficial effects of angiotensin-converting enzyme inhibition after AMI. However, the nature of this effect is not completely understood. METHODS AND RESULTS: We included 89 patients within 48 hours after onset of a first AMI and radionuclide left ventricular ejection fraction less than 45%. The study was double-blind and compared enalapril and placebo with a crossover design. All patients were randomly assigned to a sequence A (enalapril, 45 days; placebo, 45 days) or B (placebo, 45 days; enalapril, 45 days). The end point was the change of left ventricular volume at 45 and 90 days. Thrombolysis was administered to 26 patients (70%) in group A and 25 (75%) in group B. All pretreatment clinical variables were similar in both groups. Median and 95% confidence intervals (CIs) of left ventricular diastolic volumes were 46.8 ml/m2 (39 to 61 ml/m2) and 46.6 ml/m2 (39 to 60 ml/m2) for groups A and B, respectively. Baseline end systolic volumes were 28.5 ml/m2 (20 to 36 ml/m2) and 28.9 ml/m2 (23 to 28 ml/m2) in the same groups. Placebo treatment during the initial 45 days was associated with an increase of left ventricular diastolic volume of 8.75 ml/m2 (95% CI, 3.25 to 17.1 ml/m2; p < 0.01) and end-systolic volume of 4.20 ml/m2 (95% CI, 0.00 to 10.1 ml/m2; p < 0.05). No significant changes during other phases of the study were observed. At 45 days left ventricular diastolic volume was 11.1 ml/m2 (95% CI, 0.5 to 2.2 ml/m2), greater in placebo-treated patients compared with patients receiving enalapril. CONCLUSIONS: In patients with a first Q wave AMI and left ventricular ejection fraction less than 45%, treatment with enalapril can prevent left ventricular dilation. This protective effect involves at least partially a structural modification of the left ventricle. Hence, maximal benefit can be obtained only with early initiation of treatment.

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.

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.

[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.

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 (AU)

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