Vet360, December 2016 - Page 18

CARDIOLOGY Pimobendan: A Treatment for Preclinical Heart Failure KE Joubert BVSc, MMedVet (Anaes) Extraordinary Lecturer: Pharmacology - Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Veterinary Anaesthesia, Analgesia & Critical Care Services, +27 82 454 7280, email: Reviewed: Marlies Bohm BVSc DSAM MMedVet(Med) DipECVIM -CA Heart disease is one of the top 5 causes of death in dogs, in the United Kingdom with 75% of these cases being from mitral valve disease (MVD). Heart disease is one of the top 5 causes of death in dogs, in the United Kingdom with 75% of these cases being from mitral valve disease (MVD). Heart failure secondary to MVD is classified according to the 2009 American College of Veterinary Internal Medicine (ACVIM) consensus statement. Stage A patients are at risk of heart disease according to their age and breed disposition with no clinical signs or evidence of heart disease. Stage B heart failure is divided into two stages. Stage B1 are asymptomatic patients without radiographic or echocardiographic evidence of compensation (i.e. heart murmur only) and stage B2 are asymptomatic patients with radiographic or echocardiographic evidence of compensation. Stage C patients have clinical heart disease with radiographic and echocardiographic evidence and require treatment to control the disease. Stage D patients are in refractory or end stage heart disease. The QUEST (Quality of Life and Extension of Survival Time) study (2008) showed that dogs, in Stage C, treated with pimobendan, in conjuction with other standard treatment, for congestive heart failure (CHF), vet360 Issue 06 | DECEMBER 2016 | 18 secondary to MVD, reached the primary end point in 267 days versus those treated with benazepril and other standard therapy, which took 140 days. The primary end points were sudden cardiac death, euthanasia due to cardiac disease or treatment failure leading to withdrawal from trial. To be included into the study dogs were required to be more than 5 years of age, weigh between 5 and 20kg, have a heart murmur of moderate to high intensity, have echocardiographic evidence of mitral valve disease and cardiac enlargement, radiographic evidence of pulmonary oedema and cardiac enlargement and clinical signs of suggestive of cardiac failure. The second part of the QUEST study was published in 2013 and evaluated the quality of life (QOL) in patients receiving either pimobendan or benazepril. Good QOL in these patients was defined as alleviation of the clinical signs caused by CHF with resumption or near resumption of normal daily activities. Patients receiving pimobendan required 98 days before treatment was intensified compared to 59 days in the benazepril group. The QOL of life was similar between the two