Page 11 - Biomarkers for risk stratification and guidance in heart failure

Chapter 1
Heart Failure (HF) is a complex clinical syndrome in which patients have symptoms (e.g. breathlessness, ankle swelling and fatigue) and signs (e.g. elevated jugular venous pressure, pulmonary crackles and displaced apex beats) resulting from an abnormality of cardiac structure or function.1 Although similarity in symptoms exists, the etiologic background of HF is quite diverse, with causes like, but not limited to, coronary artery disease, hypertension, cardiomyopathy and cardiac valve disease.1
Approximately 1-2% of the adult population in developed countries has HF, with prevalence rising to more than 10% among persons 70 years or older.2 The incidence of HF is likely to rise in the near future due to ageing and improved treatment of hypertension as well as valvular and coronary heart disease, allowing patients to survive an early death to later develop HF. It is estimated that in the Netherlands, incidence of HF will rise from 142.000 in 2011 to more than 225.000 patients in 2030.3 Last decades, treatment of HF has markedly improved by prescription of ACE-inhibitors, AT-2 antagonists, Betablockers, aldosterone receptor antagonists and recently the addition of ivabradine and the neprilysin inhibitor sacubitril to the therapeutic arsenal of HF.4-9 Furthermore, introduction of the ICD and biventricular pacing devices has clearly improved prognosis.10,11 Nevertheless, morbidity and mortality of HF remains high, especially after admission because of acute HF. A retrospective cohort trial of more than 2.5 million Americans aged above 65 years demonstrated 30-day, 180-day and one year mortality rate of 11%, 26% and 37% respectively, and a one year readmission rate of 65%.12 Consequently, HF treatment has high impact on health care cost, with 940 million euro spent on treatment of HF in the Netherlands, which was more than 1% of the national health care budget.13
1.1 Dyspnea: one symptom, many causes.
In the majority of patients presenting to the cardiac emergency department (ED) with HF, dyspnea is the main complaint.14 Dyspnea, or shortness of breath is defined as an uncomfortable abnormal awareness of breathing. The pathophysiologic mechanism of dyspnea is complex and only partially understood15. Dyspnea can be caused by a wide variety of diseases like COPD, pneumonia, pulmonary embolism, coronary artery disease and HF, although the cause is often multifactorial.16 HF has reported to be the most frequent cause of dyspnea at the ED (34%17– 58%18), and in specialized cardiac emergency departments the incidence of HF among dyspneic patients is expected to be even higher. As dyspnea can be caused by both harmless as well as highly lethal
10