Emergency visits and mortality caused by ischemic heart disease attributable to fine particulate matter during the COVID-19 pandemic in Chile.

POSITION DU PROBLèME: Le confinement mis en place au deuxième trimestre 2020 a entrainé une amélioration de la qualité de l'air de Santiago, capitale et plus grande ville du Chili, caractérisée par de fortes concentrations en particules fines PM2,5 liées, en grande partie, au trafic routier. L'objectif était de mettre en évidence une potentielle réduction des visites aux urgences pour infarctus du myocarde aigu (IDM) et des décès dus à une cardiopathie ischémique (CPI) attribuable à l'émission de PM2,5, en comparant les périodes équivalentes de 2019 et de 2020. MéTHODES: À Santiago, la surveillance de la qualité de l'air se fait grâce à neuf moniteurs situés dans neuf communes différentes : Cerro Navia, Cerrillos, El Bosque, Pudahuel, Independencia, La Florida, Quilicura, Santiago centre-ville et Las Condes (classées de la plus haute à la plus basse en matière de pauvreté multidimensionnelle). La concentration moyenne quotidienne de PM2,5 a été décrite avec des séries temporelles, et les visites aux urgences pour IDM et les décès dus à une CPI ont été analysés de façon trimestrielle pour chaque année. Pour estimer l'impact de l'excès de PM2,5, les fractions de risque attribuables (FRA) pour les visites aux urgences pour IDM et les décès pour CPI ont été calculées. RéSULTATS: La moyenne quotidienne des PM2,5 a diminué dans huit des neuf communes de Santiago. Cependant, la réduction n'a été significative que dans trois communes. Les visites aux urgences pour IDM et les décès par CPI attribuables aux PM2,5 ont diminué légèrement mais significativement dans ces trois communes. Les FRA dans les autres communes sont restées similaires à 2019. CONCLUSIONS: Une réduction significative de la FRA des PM2,5 pour les décès par CPI et les visites aux urgences d'IDM n'a été observée que dans les communes avec une réduction significative de la concentration quotidienne moyenne de PM2,5 pendant la pandémie de COVID-19.

Trombosis en el infarto agudo del miocardio en hospitales chilenos: la experiencia del grupo GEMI / Thrombolysis in the acute myocardial infarction in chilean hospitals: the gemi group experience

Antecedentes: La trombolisis es uno de los métodos de reperfusión coronaria que permite reducir la mortalidad del infarto agudo del miocardio (IAM). Lamentablemente no todos los pacientes con indicación de trombolítico reciben el tratamiento. Objetivo: Evaluar los cambios en el empleo de trombolíticos a través del tiempo en pacientes con IAM y supradesnivel ST y analizar las variaciones en mortalidad según el período de registro. Método: Se compara la información de tres registros efectuados los años 93-95 (R1), 97-98 (R2), y los pacientes incluidos en el año 2001 del registro GEMI actualmente en curso (R3), en el que participan 23 hospitales de Santiago y regiones. Se recolecto información sobre latencia en administración del trombolítico, motivo de la no utilización y evolución intrahospitalaria de los pacientes que ingresaron con el diagnóstico de IAM Q o con supradesnivel ST (SDST). Resultados: En R1 se recolectaron 2.155 pacientes con IAM y SDST, en R2: 1.436 pacientes y en R3: 789 pacientes. El porcentaje que recibió trombolíticos fue de 37,8 por ciento, 41,4 por ciento y 45,1 por ciento, respectivamente. La mortalidad global en cada uno de los registros fue de R1: 11,2 por ciento, R2: 9,9 por ciento y R3: 8,9 por ciento ( p para tendencias: NS). Cuando se analiza según sexo, la mortalidad en hombres fue de 8,1 por ciento 7,4 por ciento y 7,1 por ciento (p para tendencias: NS). En mujeres estas proporciones fueron 23,6 por ciento 19,2 por ciento y 14,8 por ciento, respectivamente (p para tendencias: <0,05). El motivo de no uso trombolítico, dato consignado en R2 y R3, se debió a: ingreso tardío (45 por ciento y 38 por ciento respectivamente), contraindicación (9,5 y 12,5), no disponibilidad de él (1,5 por ciento y 0,23 por ciento). En el resto de los pacientes se consignó como “otro” el motivo de no uso. (De este análisis se excluyeron los pacientes sometidos a angioplastia primaria). Se observa un aumento en la proporción de pacientes sometidos a trombosis, asociado a una reducción en la mortalidad global en ellos. Conclusión: La reducción de la mortalidad en mujeres es determinante en la mejoría del pronóstico intrahospitalario en la población de trombolisados. Estos hallazgos pueden reflejar una mejor indicación y oportunidad del empleo de trombolíticos, así como de los fármacos de eficacia demostrada para el tratamiento de IAM con SDST...

Association of noninvasive markers of coronary artery reperfusion to assess microvascular obstruction in patients with acute myocardial infarction treated with primary angioplasty.

Early restoration of coronary artery patency through primary angioplasty limits infarct size and improves survival. Increasing evidence, however, suggests that microvascular obstruction is often present despite coronary artery recanalization. This may limit the benefits of reperfusion therapy. We studied the use of noninvasive markers of coronary artery reperfusion as indicators of microvascular obstruction and determinants of prognosis in 98 patients with acute myocardial infarction (AMI) who were successfully treated with primary angioplasty (Thrombolysis In Myocardial Infarction grade 3 flow and residual stenosis <30%). Plasma creatine kinase (CK) levels and 12-lead electrocardiograms were performed on admission, at 90 minutes, and at 6, 12, and 24 hours after treatment. We defined: (1) reperfusion as resolution of ST-segment elevation >50% at 90 minutes, with peak CK levels within 12 hours, and T-wave inversion within 24 hours; and (2) failed reperfusion, as the absence of these parameters. Of the 98 patients studied, 87 (88.8%) had reperfusion and 11 (11.2%) had failed reperfusion. Infarct location was anterior (versus inferior) in 9 patients in the failed reperfusion group (81.8%) compared with 41 patients in the reperfusion group (47.1%) (p <0.01). Congestive heart failure >24 hours after presentation or in-hospital death occurred in 11 patients (12.6%) in the reperfusion group versus 5 (45.5%) in the failed reperfusion group (p <0.01). One-year survival was 96.1% for the reperfusion group and 60.6% for the failed reperfusion group (p <0.0001). We conclude that the association of noninvasive markers of reperfusion better identifies patients with microvascular obstruction among those who had a "successful" primary angioplasty. Evidence of impaired microvascular reperfusion is associated with a poor in-hospital and 1-year outcome.

Bedside markers of coronary artery patency and short-term prognosis of patients with acute myocardial infarction and thrombolysis.

BACKGROUND: In this study we have evaluated the prognostic power of noninvasive markers of coronary artery reperfusion in patients with acute myocardial infarction who were treated with intravenous streptokinase. METHODS: In 967 consecutive patients with acute myocardial infarction who were treated within 6 hours of symptoms, we analyzed the prognostic power of resolution of chest pain and ST-segment elevation >50% at 90 minutes, abrupt creatine kinase rise before 12 hours, and T-wave inversion in infarct-related electrocardiographic leads within the first 24 hours after thrombolysis. RESULTS: Global in-hospital mortality rate was 12.0%. Each reperfusion marker was associated with improved outcome. Multivariate logistic regression analysis showed that 3 of the 4 markers of coronary artery reperfusion were significantly and independently associated to low in-hospital mortality rate. The presence of early T-wave inversion was associated with the lowest in-hospital mortality rate (odds ratio 0.25, confidence interval 0. 10-0.56). When all markers of coronary artery reperfusion were included in the regression model, T-wave inversion (odds ratio 0.29, confidence interval 0.11-0.68) and abrupt creatine kinase rise (odds ratio 0.36, confidence interval 0.16-0.77) continued to be significantly associated with better outcome. CONCLUSION: A systemic analysis of noninvasive markers of coronary artery reperfusion can provide the clinician with an excellent tool to predict clinical outcomes when treating myocardial infarction.

[Acute myocardial infarction in Chilean hospitals. Final results of the GEMI study]. / Infarto agudo del miocardio en hospitales chilenos. Resultados finales del estudio GEMI. Grupo de Estudio Multicéntrico del Infarto (GEMI).

BACKGROUND: Acute myocardial infarction is the leading cause of death in Chile. AIM: To report the main features, hospital evolution, complications and pharmacological treatment of patients admitted to Chilean hospitals with the diagnosis of acute myocardial infarction. PATIENTS AND METHODS: Between 1993 and 1995, the GEMI group registered 2,957 patients admitted to 37 hospitals with the diagnosis of acute myocardial infarction. RESULTS: Mean age of patients was 62 +/- 2 years old and 74% were male. Forty six percent had a history of hypertension and 40% were smokers. During the first five days of admission, 93% of patients received aspirin, 95% received intravenous nitrates, 59% intravenous heparin, 56% oral nitrates, 37% beta blockers, 32% angiotensin-converting enzyme inhibitors, 33% thrombolytic agents, 29% antiarrhythmics and 23% calcium antagonists. Coronary angiograms were performed in 28% of patients, angioplasty in 9% and 8% were subjected to a coronary bypass. Global hospital mortality was 13.4% (19.5% in women and 11.1% in men, p < 0.001). CONCLUSIONS: This work gives a picture of myocardial infarction in Chilean hospitals. Pharmacological treatment is similar to that used abroad, but certainly it can be optimized.

[Prognostic value of noninvasive makers of coronary reperfusion in patients with acute myocardial infarction treated with thrombolysis]. / Valor pronóstico de los índices no invasivos de reperfusión coronaria en pacientes con infarto agudo del miocardio tratados con trombolisis.

BACKGROUND: The immediate prognosis of patients with acute myocardial infarction treated with thrombolysis primarily depends on obtaining a satisfactory coronary reperfusion. AIM: To assess the prognostic power of four markers of coronary artery patency in patients with acute myocardial infarction treated with Streptokinase 1.5 million U within the first six hours of symptoms. PATIENTS AND METHODS: In 807 consecutive patients from the Chilean National Registry of Acute Myocardial Infarction we analyzed the resolution of chest pain and ST segment elevation over 50% within the first 90 min, abrupt CK rise within 8 h and T wave inversion in infarct related EKG leads within the first 24 h after thrombolysis. RESULTS: Global in-hospital mortality was 12.1%. Mortality of patients with the presence of 3 or 4 markers of coronary artery patency was 5.1%, in those with resolution of ST elevation and abrupt CK rise was 6.25% and in those with T wave inversion it was 3.9% (p < 0.001). Multivariate analysis, adjusted by age, gender, risk factors, Killip class and infarct location showed that early T wave inversion was the better predictor of a low in-hospital mortality and that its combination with other markers of coronary artery patency did not increase its prognostic power. Early CK rise and the presence of 3 out of 4 reperfusion criteria were also independent predictors of a low mortality. CONCLUSIONS: Non invasive markers of coronary artery patency are associated with a lower in-hospital mortality and may serve as surrogate end points in clinical trials.

[Acute myocardial infarction in Chile: differences between men and women in its evolution and prognosis. Multicenter Study Group on Infarction] (GEMI)]. / Infarto agudo del miocardio en Chile: diferencias entre hombres y mujeres en su evolución y pronóstico. Grupo de Estudios Multicéntrico de Infarto (GEMI).

BACKGROUND: Gender may be a prognostic factor for the evolution of acute myocardial infarction and women may have higher mortality and complication rates. AIM: To study if there are differences in the evolution of acute myocardial infarction between men and women. PATIENT AND METHODS: We have recorded information on risk factors, clinical evolution, treatment and complications of 2,052 patients hospitalized for acute myocardial infarction in 36 Chilean hospitals. The odds ratio for female sex and mortality was calculated using a logistic regression analysis adjusted for risk factors, treatment, invasive procedures and complications. RESULTS: Twenty six percent of analyzed patients were female. Mortality rates among females and males were 11.8 and 20.2% respectively (p < 0.01). Women had higher frequency of smoking, diabetes, obesity and hypertension. Blood lipid levels were similar in both sexes. Compared to men, a lesser proportion of women were treated with thrombolytic agents (25 and 35% respectively), intravenous heparin (54 and 61% respectively), beta blockers (31 and 42% respectively) and intravenous nitrates (53 and 61% respectively). Also, women were subjected to less invasive procedures. The odds ratio for mortality and sex was 1.72 (confidence interval from 1.13 to 2.62). CONCLUSIONS: Female sex is an independent risk factor for acute myocardial infarction mortality.