Comparison between Bruce and ramp protocols for exercise testing in the diagnosis of myocardial ischemia

BACKGROUND: Exercise tests are an important tool in the investigation of myocardial ischemia. The ramp protocol has gained increasing importance in clinical practice because of the possibility of individualizing its exercise intensity. OBJECTIVE: To assess and compare the sensitivity, specificity, and accuracy of Bruce and ramp protocols for exercise testing in the diagnosis of myocardial ischemia considering myocardial perfusion scintigraphy as the reference standard. Secondary objectives included the assessment of hemodynamic profiles, functional capacity, and the incidence of arrhythmias in each of the protocols. METHODS: Participants underwent exercise testing using the ramp and Bruce protocols, and the tests' diagnostic power was assessed. For testing the difference between data provided by both protocols, we used a paired Student's t-test or Wilcoxon test, depending on the assumption of data normality. The level of significance adopted for all tests was 5%. RESULTS: The ramp protocol showed sensitivity, specificity, and accuracy values of 55.6%, 82.4%, and 76.7%, respectively, whereas the Bruce protocol had results of 77.8%, 64.7%, and 67.4%, respectively. The maximum heart rate and double product at peak exercise were significantly higher in the Bruce protocol (p = 0.043 and p = 0.040, respectively). No differences were observed between the incidence of arrhythmias in both protocols. CONCLUSION: The Bruce protocol presented higher sensitivity for detecting ischemia on the exercise test, while the ramp protocol presented higher specificity and accuracy.

Biomarcadores cardíacos na avaliação da síndrome coronariana aguda: [revisão] / Cardiac biomarkers for assessment of acute coronary syndrome: [review]

Objetivos: abordar o uso dos biomarcadores cardíacos associados à necrose, inflamação, desestabilização da placa, isquemia e disfunção cardíaca na avaliação da síndrome coronariana aguda a fim de propiciar a melhor compreensão sobre as vantagens e desvantagens do uso clínico desses biomarcadores laboratoriais.Fonte de dados: artigos científicos originais e de revisão indexados nas bases de dados PubMed e SciELO.Síntese dos dados: as doenças cardiovasculares, especialmente a síndrome coronariana aguda, representam a principal causa de mortalidade no Brasil e no mundo, sendo que seu contínuo crescimento representa uma das questões de saúde pública mais relevantes da atualidade. Nesse sentido, os biomarcadores cardíacos constituem elementos fundamentais para o diagnóstico da síndrome coronariana aguda, sendo que as troponinas cardíacas continuam sendo consideradas o padrão ouro para o diagnóstico. Com o desenvolvimento dos recentes métodos ultrassensíveis para mensuração das troponinas cardíacas, tem sido possível detectar a lesão cardíaca dentro de duas horas, melhorando substancialmente o diagnóstico precoce do infarto agudo do miocárdio. Outros biomarcadores vêm apresentando relevância, especialmente em relação ao prognóstico e estratificação de risco dos pacientes com cardiopatia isquêmica.Conclusões: vários marcadores têm apresentado eficácia na detecção da necrose, isquemia, inflamação, desestabilização da placa e disfunção cardíaca. No entanto, as troponinas cardíacas continuam sendo consideradas o padrão ouro para o diagnóstico do infarto agudo do miocárdio.

Aims: To address the use of cardiac biomarkers associated with necrosis, inflammation, plaque destabilization, and cardiac ischemia in the evaluation of acute coronary syndrome in order to provide a better understanding of the advantages and disadvantages of the clinical use of these biomarkers.Source of data: Scientific original and review articles from the PubMed and SciELO databases.Summary of findings: Cardiovascular diseases, especially acute coronary syndrome, are the leading cause of mortality in Brazil and worldwide, and its continued growth is one of public health issues most relevant today. In this sense, the cardiac biomarkers are key to the diagnosis of acute coronary syndrome, and the cardiac troponins are still considered the gold standard for its diagnosis. With the recent development of ultra-sensitive methods for measuring cardiac troponins, it has been possible to detect heart damage within two hours, substantially improving the early diagnosis of acute myocardial infarction. Other biomarkers have been showing relevance, especially in relation to prognosis and risk stratification of patients with ischemic heart disease.Conclusions: Several biomarkers have shown efficacy in the detection of necrosis, ischemia, inflammation, plaque destabilization and cardiac dysfunction. However, cardiac troponins are still considered the gold standard for diagnosis of acute myocardial infarction.