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: [email protected]
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),
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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