Respiratory muscle weakness and chronic heart failure biomarkers: a study of association

• Grant number: 17/01113-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2017
• End date: May 31, 2018
• Field of knowledge: Health Sciences - Physiotherapy and Occupational Therapy
• Principal Investigator: Naomi Kondo Nakagawa
• Grantee: Mariana de Abreu Diz
• Host Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Chronic heart failure is a multisystemic illness that reduces blood flow to organs and systems that in turn reduce functional capacity. Among factors that reduce functional capacity in patients with heart failure, resistance and strenght muscle are altered by low capillary blood flow, reduced oxidative capacity, increased levels of angiotensin II and replacement of muscle fiber I to fiber II. In this context, it is common a clinical deleterious evolution such as fatigue, hyperventilation and peripherical and respiratory muscle weakness. The prevalence of respiratory muscle weakness in patients with chronic heart failure is 30 to 50%. However, little is known on laboratorial risk factors to respiratory muscle weakness in chronic heart failure. This study aims: (a) to investigate the prevalence of inspiratory muscle weakness in patients with chronic heart failure NYHA II and III, (b) to investigate the threshold predict value of maximum expiratory pressure and (c) to investigate whether there is association between respiratory muscle weakness and endotelial injury and inflammatory biomarkers in patients with moderate chronic heart failure. Fifty-five adult patients (aged e 18 years), both gender, with chronic heart failure NYHA II or III that were stable in the last 3 months and after given informed written consente. Patients with chronic heart failure will be submitted to clinical assessments and laboratorial blood analysis of endotelial and inflammatory cytokines using ELISA. The exclusion criteria are: (a) atrial and ventricular complex arrhythmia, (b) peripheric oxygen saturation lower than 92%, (c) pulmonary or upper airway infection in the last 30 days, (d) chronic obstructive pulmonary disease, (e) current smoking and (f) cognitive, neurological or orthopedic limitations that do not allow testings. Pearson or Spearman correlations between variables will be used and a p-value p<0.05 will be considered as statistically significant. Our study will light on risk factors to respiratory muscle weakness in patients with chronic heart failure II and III. (AU)