Page 201 - BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, 2nd Edition

Chapter 15
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Surgery of the heart, pericardium

and great vessels

Daniel J. Brockman

Introduction with all surgical procedures, but a detailed understanding
of the anatomy and pathoanatomy of VRA, PDA, and the
There are a wide variety of acquired and congenital condi- pericardium and associated structures should allow most
tions that affect the heart, pericardium or great vessels for practised surgeons to attempt these procedures. Again,
which there are either proven or potential surgical treat- this may be justified if the alternative is euthanasia.
ments. The operations required to effect these therapies
are divided into two broad categories: extracardiac and
intracardiac. The most common conditions that require
extracardiac dissection to execute the surgical treatment Optimizing safety when
are patent ductus arteriosus (PDA), vascular ring anoma- dissecting near the heart and
lies (VRA) and diseases that require partial pericardectomy
for either palliation or definitive treatment. More occasion- great vessels
ally, animals with neoplasms such as right atrial haem-
angiosarcoma, and those with some rare congenital heart Although this chapter is not going to describe intracardiac
conditions, such as tetralogy of Fallot, can be managed surgical techniques, there are two surgical manoeuvres
successfully using extracardiac manipulations. that are useful when dissection around the heart and great
As is the case in humans, intracardiac surgery that vessels is undertaken. These techniques will allow short-
needs prolonged ‘open heart’ time requires cardiopulmo- term cessation of blood flow through the heart so that
nary bypass (CPB) to be done safely. Although CPB is in vascular forceps can be placed accurately, should bleed-
widespread use in human medicine, it is only available at a ing occur from a major vessel. Bleeding from a ruptured
few specialist veterinary centres around the world. PDA or the right auricular appendage can be profuse and
Intracardiac surgical therapy can be performed success- rapidly fatal, so these ‘safety’ manoeuvres should be pre-
fully under conditions of temporary vascular occlusion pared before any dissection around these structures is
(typically total venous inflow occlusion (TVIO)), providing done, and deployed when needed. The two techniques are
the intracardiac manipulations required are not compli- TVIO and total cardiac outflow occlusion (TCOO). In addi-
cated and can be completed within the 5–8-minute tion to these surgical manoeuvres, it is important that the
window that TVIO can provide. Such conditions include anaesthesia and surgery team are appropriately prepared,
some types of valvular pulmonic stenosis, double- blood products are available and the patient has sufficient
chambered right ventricle and cor triatriatum dexter. Even intravenous access sites to allow rapid infusion of blood,
though these conditions can be managed successfully should it become necessary. In the author’s practice, pre-
without cardiopulmonary bypass, in humans these opera- operative, intraoperative and postoperative checklists have
tions are done more safely, more accurately and, therefore, been created for all surgical procedures, in an attempt to
with more consistent results, under conditions of CPB. It is minimize the risk of errors. They have also adopted a ‘time
anticipated that, in centres that offer these techniques for out’ culture where the surgery, anaesthesia and nursing
animals, this will also be the case for open heart surgery teams confirm the patient identification, procedure to be
under CPB in dogs. Such techniques are beyond the performed, anticipated concerns and equipment avail a-
scope of this manual. bility, immediately prior to commencing surgery, to reduce
This chapter will focus on conditions and techniques errors and focus the team.
that would be appropriate and reasonable for a skilled
practitioner to attempt. It is safe for the reader to assume,
however, that all of these procedures could be quite Total venous inflow occlusion
reasonably designated ‘specialist’, from either a diag nostic TVIO is achieved by placing Rummel snares around the
perspective, a therapeutic perspective, or both, and as cranial and caudal vena cavae and the azygos vein. These
such would always benefit from the attention of a specialist vessels are easily identified from a right lateral approach or
team. That said, owners may decide not to pursue special- a ventral sternotomy but require a little more dissection
ist treatment for a variety of reasons and so the only option, from a left-sided approach. Typically, these tourniquets are
if therapy is to be pursued, will be to attempt such surgery placed and kept loose until they are needed. In healthy
in a practice setting. Of course, there is a learning curve dogs, uneventful resuscitation should be possible after up

192 BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, second edition. Edited by Daniel J. Brockman, David E. Holt and Gert ter Haar. ©BSAVA 2018

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