Risk factor paradox in the occurrence of cardiac arrest in acute coronary syndrome patients

Rev Bras Ter Intensiva. 2016 Oct-Dec;28(4):405-412. doi: 10.5935/0103-507X.20160065. Epub 2016 Dec 1.
[Article in Portuguese, English]

Abstract

Objective:: To compare patients without previously diagnosed cardiovascular risk factors) and patients with one or more risk factors admitted with acute coronary syndrome.

Methods:: This was a retrospective analysis of patients admitted with first episode of acute coronary syndrome without previous heart disease, who were included in a national acute coronary syndrome registry. The patients were divided according to the number of risk factors, as follows: 0 risk factor (G0), 1 or 2 risk factors (G1 - 2) and 3 or more risk factors (G ≥ 3). Comparative analysis was performed between the three groups, and independent predictors of cardiac arrest and death were studied.

Results:: A total of 5,518 patients were studied, of which 72.2% were male and the mean age was 64 ± 14 years. G0 had a greater incidence of ST-segment elevation myocardial infarction, with the left anterior descending artery being the most frequently involved vessel, and a lower prevalence of multivessel disease. Even though G0 had a lower Killip class (96% in Killip I; p < 0.001) and higher ejection fraction (G0 56 ± 10% versus G1 - 2 and G ≥ 3 53 ± 12%; p = 0.024) on admission, there was a significant higher incidence of cardiac arrest. Multivariate analysis identified the absence of risk factors as an independent predictor of cardiac arrest (OR 2.78; p = 0.019). Hospital mortality was slightly higher in G0, although this difference was not significant. By Cox regression analysis, the number of risk factors was found not to be associated with mortality. Predictors of death at 1 year follow up included age (OR 1.05; p < 0.001), ST-segment elevation myocardial infarction (OR 1.94; p = 0.003) and ejection fraction < 50% (OR 2.34; p < 0.001).

Conclusion:: Even though the group without risk factors was composed of younger patients with fewer comorbidities, better left ventricular function and less extensive coronary disease, the absence of risk factors was an independent predictor of cardiac arrest.

Objetivo: Comparar pacientes admitidos com síndrome coronariana aguda sem prévia identificação de fatores de risco cardiovascular com pacientes que portavam um ou mais fatores de risco.

Métodos: Análise retrospectiva dos pacientes admitidos com o primeiro episódio de síndrome coronariana aguda sem cardiopatia prévia, incluídos em um registro nacional de síndrome coronariana aguda. Os pacientes foram divididos segundo o número de fatores de risco: nenhum fator de risco (G0), um ou dois fatores de risco (G1 - 2) e três ou mais fatores de risco (G ≥ 3). Realizou-se uma análise comparativa entre os três grupos e se estudaram os preditores independentes de parada cardíaca e óbito.

Resultados: O total apurado foi de 5.518 pacientes, 72,2% deles do sexo masculino, com média de idade de 64 ± 14 anos. O G0 teve uma incidência maior de infarto do miocárdio com elevação do segmento ST, sendo o vaso mais frequentemente envolvido a artéria descendente anterior esquerda, e menor prevalência de envolvimento de múltiplos vasos. Embora o G0 tivesse uma classe Killip mais baixa (96% Killip I; p < 0,001) e maior fração de ejeção (G0: 56 ± 10% versus G1 - 2 e G ≥ 3: 53 ± 12%; p = 0,024) na admissão, houve incidência significantemente maior de parada cardíaca. A análise multivariada identificou ausência de fatores de risco como um fator independente para parada cardíaca (OR 2,78; p = 0,019). A mortalidade hospitalar foi ligeiramente maior no G0, embora sem significância estatística. Segundo a análise de regressão de Cox, o número de fatores de risco não se associou com mortalidade. Os preditores de óbito em 1 ano de seguimento foram infarto do miocárdio com elevação do segmento ST (OR 1,05; p < 0,001) e fração de ejeção inferior a 50% (OR 2,34; p < 0,001).

Conclusão: Embora o grupo sem fatores de risco fosse composto de pacientes mais jovens e com menos comorbidades, melhor função ventricular esquerda e coronariopatia menos extensa, a ausência de fatores de risco foi um preditor independente de parada cardíaca.

MeSH terms

  • Acute Coronary Syndrome / epidemiology
  • Acute Coronary Syndrome / etiology*
  • Adult
  • Age Factors
  • Aged
  • Female
  • Follow-Up Studies
  • Heart Arrest / epidemiology
  • Heart Arrest / etiology*
  • Hospital Mortality
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Proportional Hazards Models
  • Retrospective Studies
  • Risk Factors
  • ST Elevation Myocardial Infarction / epidemiology
  • ST Elevation Myocardial Infarction / etiology*
  • Ventricular Function, Left*