Cardiac Dysfunction, Congestion and Loop Diuretics: their Relationship to Prognosis in Heart Failure

Background: Diuretics are the mainstay of treatment for congestion but concerns exist that they adversely affect prognosis. We explored whether the relationship between loop diuretic use and outcome is explained by the underlying severity of congestion amongst patients referred with suspected heart failure. Method and Results: Of 1190 patients, 712 had a left ventricular ejection fraction (LVEF) ≤50 %, 267 had LVEF >50 % with raised plasma NTproBNP (>400 ng/L) and 211 had LVEF >50 % with NTproBNP ≤400 ng/L; respectively, 72 %, 68 % and 37 % of these groups were treated with loop diuretics including 28 %, 29 % and 10 % in doses ≥80 mg furosemide equivalent/day. Compared to patients with cardiac dysfunction (either LVEF ≤50 % or NT-proBNP >400 ng/L) but not taking a loop diuretic, those taking a loop diuretic were older and had more clinical evidence of congestion, renal dysfunction, anaemia and hyponatraemia. During a median follow-up of 934 (IQR: 513–1425) days, 450 patients were hospitalized for HF or died. Patients prescribed loop diuretics had a worse outcome. However, in multi-variable models, clinical, echocardiographic (inferior vena cava diameter), and biochemical (NTproBNP) measures of congestion were strongly associated with an adverse outcome but not the use, or dose, of loop diuretics. Conclusions: Prescription of loop diuretics identifies patients with more advanced features of heart failure and congestion, which may account for their worse prognosis. Further research is needed to clarify the relationship between loop diuretic agents and outcome; imaging and biochemical measures of congestion might be better guides to diuretic dose than symptoms or clinical signs

Teste cardiopulmonar do exercício na prática clínica Cardiopulmonary stress testing in clinical practice

O teste cardiopulmonar do exercício (CPX) apresenta-se como uma metodologia de grande utilidade diagnóstica e prognóstica. O presente estudo teve por objetivo demonstrar que os dados obtidos em laboratório fora do ambiente hospitalar comportam-se como os dados descritos na literatura, com aplicabilidade na prática clínica em nosso meio. METODOLOGIA: Trata-se de um relato de experiência, através da análise retrospectiva dos casos. O CPX foi realizado em condições de laboratório controladas, com bocal e clipe nasal, protocolo de rampa em esteira rolante e eletrocardiograma de 13 canais. RESULTADOS: Entre os 261 testes, 53,3% eram em homens, idade média de 48,2 ± 14,3 anos; ativos (45,2%) ou sedentários (34,5%). A capacidade aeróbia máxima foi superior e com declínio significativo para cada década de aumento na faixa etária entre os homens, enquanto nas mulheres o declínio significativo ocorreu entre os 30 e 60 anos. As mulheres apresentaram maior distribuição (p = 0,0006) nas classes funcionais "em programa de treinamento ou bem treinadas e motivadas". O consumo de oxigênio pico (<img border=0 width=32 height=32 src="../../../../../img/revistas/rbme/v6n6/V-com-pontinho-menor.gif">O2) foi significativamente superior nos testes máximos, mas o <img border=0 width=32 height=32 src="../../../../../img/revistas/rbme/v6n6/V-com-pontinho-menor.gif">O2 do limiar anaeróbio (<img border=0 width=32 height=32 src="../../../../../img/revistas/rbme/v6n6/V-com-pontinho-menor.gif">O2LA) não apresentou diferenças significativas, quando o teste obtido foi máximo ou submáximo. A capacidade funcional, avaliada pelo <img border=0 width=32 height=32 src="../../../../../img/revistas/rbme/v6n6/V-com-pontinho-menor.gif">O2LA como porcentagem do <img border=0 width=32 height=32 src="../../../../../img/revistas/rbme/v6n6/V-com-pontinho-menor.gif">O2 máximo previsto, comparado à porcentagem do <img border=0 width=32 height=32 src="../../../../../img/revistas/rbme/v6n6/V-com-pontinho-menor.gif">O2 máximo atingido, classificou mais indivíduos com compromisso circulatório (p = 0,002) ou com menor aptidão física em comparação com pacientes ativos ou em programa de treinamento (p < 0,00001), exceto quando entre 50,0 e 59,0%, em que o critério empregado não influenciou a classificação funcional (p = 0,221). Não haver atingido 85,0% do <img border=0 width=32 height=32 src="../../../../../img/revistas/rbme/v6n6/V-com-pontinho-menor.gif">O2 máximo previsto foi a causa mais comum de anormalidade, mais freqüente e significativo entre as mulheres. CONCLUSÃO: Os dados obtidos são comparáveis aos descritos na literatura, sugerindo que o CPX é uma metodologia factível, que poderia ser empregada rotineiramente na prática clínica em nosso meio.<br>Cardiopulmonary stress testing (CPT) is a very useful tool to determine the diagnosis and prognosis in clinical practice. The objective of this study is to demonstrate that data obtained in a laboratory outside the hospital are similar to those described in the literature. METHODOLOGY: Patients were submitted to CPT, treadmill ramp protocol, and 13 lead electrocardiogram to evaluate CPT in the clinical practice. RESULTS: Among 261 CPT, 53.3% were male, mean age 48.2 ± 14.3 years, with active (45.2%) or sedentary (34.5%) lifestyle. Male patients showed higher maximal aerobic capacity (<img border=0 width=32 height=32 src="../../../../../img/revistas/rbme/v6n6/V-com-pontinho-menor.gif">O2 max) and a significant decrease of <img border=0 width=32 height=32 src="../../../../../img/revistas/rbme/v6n6/V-com-pontinho-menor.gif">O2 for each ten years of increment in age, but it decreased from 30 to 69 years in females. Females showed a significant higher (p = 0.0006) distribution in functional classes described as "in training programs or well trained and high motivation". A <img border=0 width=32 height=32 src="../../../../../img/revistas/rbme/v6n6/V-com-pontinho-menor.gif">O2 max was superior in maximal effort tests, but anaerobic threshold (<img border=0 width=32 height=32 src="../../../../../img/revistas/rbme/v6n6/V-com-pontinho-menor.gif">O2AT) did not show differences between maximal or submaximal tests. The functionalcapacity evaluated by <img border=0 width=32 height=32 src="../../../../../img/revistas/rbme/v6n6/V-com-pontinho-menor.gif">O2AT as a fraction (%) of the <img border=0 width=32 height=32 src="../../../../../img/revistas/rbme/v6n6/V-com-pontinho-menor.gif">O2 max predicted in comparison to the fraction of the <img border=0 width=32 height=32 src="../../../../../img/revistas/rbme/v6n6/V-com-pontinho-menor.gif">O2 max measured was more rigorous, which implies a higher number of patients with circulatory impairment (p = 0.002) and also with lower physical capacity as opposed to active patients or patients under training programs (p < 0.00001); however, between 50.0% and 59.0% of the patients could be classified equally by one or the other criteria (p = 0.221). The more frequent abnormality in CPT was that it did not achieve 85.0% of the <img border=0 width=32 height=32 src="../../../../../img/revistas/rbme/v6n6/V-com-pontinho-menor.gif">O2 max predicted, more significant for females. CONCLUSION: Despite the limitations, this experience indicates that CPT data are reproducible in a laboratory outside the hospital, suggesting that CPT may be applied in clinical practice