What is mean and model life expectancy in NYHA I-IV heart failure?

The New York Heart Association (NYHA) first published its Criteria for diagnosis and treatment of heart disease in 1928. The ninth and latest edition, published in 1994,1 retains an assessment of the functional capacity of the patient with heart disease. The NYHA functional capacity score is an entirely subjective assessment of a patient’s cardiovascular status and is independent of objective measures of cardiovascular structure and function. Despite this it remains a quick, simple and reproducible evaluation of the patient with heart failure. In testament to this, NYHA class can consistently predict mortality in chronic heart failure having now been established as an independent prognostic variable in this condition in many large, epidemiological studies and clinical trials. The majority of patients with class IV functional status have end stage disease, the poorest prognosis and represent a relatively small group. Most patients are therefore classified with class II or III symptoms. Larger studies have reported mortality data across all NYHA classes. Typically the mortality rates for one and three years respectively are, class I/II 82% and 52%, class III 77% and 34% and class IV 41% and 0%.2

Hospital series include those with acutely decompensated disease. Whether such patients can be classified according to NYHA criteria is open to debate, but they might be considered in class IV. Survival of just 33% at two year follow up has been reported for this group in a Canadian study.3 The burden of heart failure in the United Kingdom is more difficult to appreciate, based on the analysis of official surveys, as death certification is based on disease aetiology rather than clinical diagnoses.

The Framingham Heart Study4 is probably the largest survey of cardiovascular disease undertaken and has data on over 9000 patients, spanning two generations, with a median follow up of 14.8 years. Mortality data in this series was not based on NYHA class but simply included those in which a diagnosis of heart failure had been made. The overall five year mortality rates were reported as 75% for men and 62% for women with a median survival of 1.66 years after the onset of congestive heart failure. After excluding the patients who died within 90 days of diagnosis (likely to contain many with NYHA class IV disease) the mortality rates fell to 65% for men and 47% for women. The authors of this study4 emphasise the grim prognosis of this disease by making comparison to the mortality rate for all cancers, which, between 1979 and 1984 was reported as 50%.

The overall prognosis for a patient diagnosed with heart failure is therefore really rather wretched. The application of the NYHA functional score provides a simple but meaningful way of stratifying such patients to help formulate management priorities. Many objective prognostic variables with equal or greater weight in predicting heart failure mortality have been elucidated, however, and account of these should be acknowledged.