While its use is widespread, the NYHA score is not very reproducible and does not reliably predict the walking distance or exercise tolerance on formal testing.In its 2001 guidelines, the American College of Cardiology/American Heart Association working group introduced four stages of heart failure:
Stage A: People at high risk for developing HF in the future, but no functional or structural heart disorder
Stage B: A structural heart disorder, but no symptoms at any stage
Stage C: Previous or current symptoms of heart failure in the context of an underlying structural heart problem, but managed with medical treatment
Stage D: Advanced disease requiring hospital-based support, a heart transplant, or palliative careThe ACC staging system is useful since stage A encompasses "pre-heart failure" – a stage where intervention with treatment can presumably prevent progression to overt symptoms. ACC stage A does not have a corresponding NYHA class. ACC stage B would correspond to NYHA class I. ACC stage C corresponds to NYHA class II and III, while ACC stage D overlaps with NYHA class IV. The degree of coexisting illness: i.e. heart failure/systemic hypertension, heart failure/pulmonary hypertension, heart failure/diabetes, heart failure/kidney failure, etc. Whether the problem is primarily increased venous back pressure (preload), or failure to supply adequate arterial perfusion (afterload)
Whether the abnormality is due to low cardiac output with high systemic vascular resistance or high cardiac output with low vascular resistance (low-output heart failure vs. high-output heart failure)

Histopathology
Histopathology can diagnose heart failure in autopsies. The presence of siderophages indicates chronic left-sided heart failure, but is not specific for it.
Vestibular papillomatosis (VP) are normal small bumps in the genital area of females. They appear in multiple numbers, are rounded and are not painful, itchy or uncomfortable. They are analogous to pearly penile papules, which occur in males.They are not infectious and are not due to HPV. Diagnosis is by visualization. The bumps are less yellow and more pinkish when compared to Fordyce spots. They should not be mistaken for genital warts. No treatment is required.They are common in pregnancy. Historically they were sometimes incorrectly called "microwarts". == References ==