Ch 106 Cardiac surgery Flashcards
Which coronary artery is dominant in dogs and cats?
Dogs - left
Cats - right
What is the first brach of the aortic arch?
Second?
Brachiocephalic trunk
Second = Left subclavian artery
anatomy
- The right and left atria are divided by an atrial septum and receive blood from the systemic and pulmonary venous circulations, respectively
- Blood is carried from the systemic circulation to the right atrium by the cranial and caudal vena cava
- azygos vein usually drains into the cranial vena cava
- cr. and ca. vena cava, azygous and the right atrium are readily accessible from the right lateral aspect
- Blood is carried to the left atrium by multiple pulmonary veins
- right atrioventricular (tricuspid) and left atrioventricular (mitral) valves
- The pericardium contains several sinuses and recesses.78 Under normal conditions, a minimal amount of fluid (0.5–1 mL in the dog) is present
- This fluid, produced by the visceral pericardial cells, is an ultrafiltrate of plasma and provides lubrication to facilitate normal movements between the epicardium and pericardium without friction.
- The atrioventricular valves composed of leaflets, chordae, and papillary muscles
- pulmonic and aortic valves (semilunar valves)
- the pulmonic valve and main pulmonary artery are accessible from the left lateral aspect of the heart
- he left and right vagus nerves run at the level of the heart base,
- left and right phrenic nerves run over the pericardium at the level of the coronary groove.
- The left recurrent laryngeal nerve originates from the left vagus at the level of the ductus or ligamentum arteriosum,
What factors determine stroke volume?
Preload
Afterload
Contractility
Cardiac Cycle and Pressure-Volume Relationship
- During each cardiac cycle, the heart accomplishes two fundamental kinds of external work. It generates pressure and it ejects volume
- pressure-volume plot: filling phase, an isovolumetric contraction phase, an ejection phase, and an isovolumetric relaxation phase.
- cardiac filling is divided into rapid diastolic filling (passive) and atrial filling (atrial systole).
- The principal volume endpoints are end-diastolic volume (EDV) and end-systolic volume (ESV). The difference between EDV and ESV is the stroke volume (SV).
Cardiac Output, Blood Pressure, and Vascular Resistance
- CO = SV and HR
- MAP = (CO x VR) + AP
- vascular resistance = vasoconstriction (i.e., vascular radius) in the resistance arteries and the viscosity of blood (i.e., hematocrit)
- pulse pressure (Pp) is the difference between the systolic and diastolic blood pressures.
- ## It is possible to have a high pulse pressure and strong pulse but a low mean arterial pressure and vice versa (PDA or aortic insufficiency,)
Electrophysiology
- Cardiomyocytes are excitable cells with a negative resting membrane potential and the ability to generate an action potential.
- predominant mechanisms supporting resting membrane potential are the electrochemical gradient for K+ across the sarcolemma established by the ATPase Na+-K+ pump
- Entry of Ca2+ into the cell during the action potential initiates contraction of the cardiomyocyte (i.e., excitation-contraction coupling).
- cardiac impulse arises from automatic (pacemaker) cells within the sinoatrial node.
- travels leftward and ventrally as a uniform wave across the atrial muscle, initiating atrial systole.
- The impulse enters the atrioventricular node and is delayed by nodal cells that conduct slowly
- atrioventricular node and is selectively conducted to the endocardial portion of the ventricular myocardium by the very fast conducting His-Purkinje conduction system > initiating ventricular systole.
AV blocks
What kinds of cardiac procedures can be performed under venous inflow occlusion?
Short procedures under 4 minutes
Anesthesia
- opioid and a benzodiazepine
- Acepromazine should generally be avoided > prolonged hypotension.
- alpha-2 agonists cause significant cardiovascular depression
- balanced protocols consisting of combinations of an inhalant; an opioid, such as fentanyl; a benzodiazepine and a neuromuscular blocking agent, such as atracurium
For what amount of time can circulatory arrest be allowed for in normotheric and hypothermic animals (32-34C)?
Normothermic - 2min
Hypothermic - 4min
What is the lowest allowable temperature for hypothermic cardiac surgery?
32C - under this the risk of v-fib increases significantly
What vessels are tourniqueted for inflow occlusion?
right or left thoracotomy
Caudal vena cava
Cranial vena cava
Azygous vein
WHat is the maximal time for aortic cross clamping during cardiac bypass?
90min
What is the main post-op complications of cardiac bypass?
SIRS
Cardiopulmonary Bypass
- an extracorporal system provides flow of oxygenated blood to the patient, resulting in a motionless and bloodless operative field
- accomplished with a heart-lung machine (three to five pumps, a temperature-controlled circulating heater/cooler water bath, an oxygen blender, a gas flowmeter, and an anesthetic vaporizer)
- Arterial cannulation of a carotid or femoral artery is preferred over direct aortic cannulation in dogs
- Blood is diverted from the right heart to the cardiopulmonary bypass circuit by means of one or two venous cannulas through a venous line.
- Bicaval venous cannulation
- cavoatrial cannula through the right auricle
- Hemodilution is desirable during cardiopulmonary bypass to counter the effects of increased blood viscosity during hypothermia (alculated volume of crystalloid solution.)
- anticoagulation by administration of heparin
- goal of maintaining a venous oxygen saturation of 70% or greater and normal lactate concentrations
- Mean arterial pressure, which should be 50 to 70 mm Hg during bypass
- (FiO2) should be adjusted to keep PaO2 above 120 mm Hg during cardiopulmonary bypass.
- complete cardiac arrest is accomplished by cross-clamping the ascending aorta (reduce risk of air embolism)
- Protection of myocardium by cardioplegia solutions (high concentration of K+ that arrests the electrical and mechanical activities, cooling to 4C)
- The heart must be de-aired before discontinuing bypass. This is accomplished by diverting venous blood back
- The heart must be de-aired before discontinuing bypass. This is accomplished by diverting venous blood back
- Protamine administered to reverse the heparin anticoagulation
Effects of Cardiopulmonary Bypass
Systemic Inflammatory Response:
- CPB triggers an inflammatory reaction, especially within the first 12 hours post-surgery. This can lead to hemorrhage, hypoxemia, circulatory collapse, arrhythmias, low urine output, and electrolyte imbalances.
Hemorrhage:
- Even with proper surgical closure, biologic effects of CPB (e.g., thrombocytopenia, coagulopathy) can lead to significant bleeding.
- Management includes careful inspection, supportive care, and administration of fresh whole blood to restore clotting factors.
Hypoxemia & Pulmonary Injury:
- CPB increases pulmonary vascular permeability, causing “pump lung” (postoperative hypoxemia).
- PEEP (5-8 cm H₂O) for 4-12 hours post-surgery helps manage this.
Circulatory Support:
- Volume expansion is needed to maintain central venous pressure (4-10 mmHg) and cardiac output.
- Plasma or blood is preferred over crystalloids to restore volume, keeping hematocrit above 30%.
Other Postoperative Concerns:
- Inotropic support may be needed for cardiac output and blood pressure maintenance.
- Ventricular tachycardia is common and can be controlled with lidocaine.
- Urine output must be monitored for 12 hours, with hypokalemia and hypocalcemia being frequent complications.
Patent Ductus Arteriosus
- fetal vessel that connects the main pulmonary artery to the descending aorta and directs venous blood away from the collapsed fetal lungs.
- It closes soon after birth during the transition from fetal to extrauterine life.
- Over time, the ductus should transform into a ligamentum
- PDA most common congenital heart defect seen in dogs
- persistant 6th aortic arch
What breeds are predisposed to PDA?
Poodles, Keeshonds, Maltese, Bichon, Yorkies, cokers etc
Heritable component in Corgis and Poodles (hypoplasia and segmental asymmetry of the ductus muscle mass that results in failure of ductus contraction
Pathophysiology
- left-to-right shunting of blood from the aorta to the pulmonary artery
- severe volume overload of the left heart, leading to left ventricular and atrial dilatation and left-sided congestive heart failure, mitral regurgitation +/- atrial fibrillation
- untreated > die from progressive heart failure before 1 year of age
- some develop suprasystemic pulmonary hypertension that reverses the direction of flow through the shunt,
- result in hypoxemia and cyanosis that is more intense in the caudal portions of the body (differential cyanosis).
- Right-to-left patent ductus arteriosus may develop as a late sequela
What causes a reverse PDA?
Supresystemic pulmonary hypertension
daignosis
left-to-right patent ductus arteriosus
- mild exercise intolerance or stunted growth
- left-sided heart failure and include severe activity intolerance, cough, exertional tachypnea, or dyspnea
- continuous murmur at the left heart base with or without continuous cardiac thrill
- Femoral pulses are bounding or hyperkinetic because of low diastolic pressures caused by shunting of blood
- RADS: left atrial and ventricular enlargement, enlargement of pulmonary vessels, and a characteristic dilatation of the descending aorta on the dorsoventral view
- Echocardiography is confirmatory and helps rule out concurrent cardiac defects (characteristic pattern of reverse turbulent flow in the pulmonary artery on Doppler)
right-to-left
- exercise intolerance and pelvic limb collapse
- Classically, the cyanosis is “differential” (i.e., more severe in the caudal mucous membranes
- usually no cardiac murmur
- polycythemia
What age is recommended for surgical treatment of a PDA?
Older than 8 weeks and younger than 16 weeks
PDA surgical options
- percutaneous placement of embolization coils
- Amplatz Canine Ductal Occluder (ACDO) devices
- surgical ligation
Even animals with severe secondary myocardial failure and functional mitral regurgitation will benefit from surgery.
surgical ligation of a right-to-left PDA is contraindicated.
What is the reported residual flow thorugh a PDA after standard ligation and the Jackson-Henderson technique?
Standard - 21%
Jackson-Henderson 53%
What nerve course over a PDA?
persistent left cranial vena cava may overlie the ductus arteriosus
Left vagus
anatomic landmark for identification of the ductus arteriosus
What suture is recommended for PDA ligation?
how to dissect around the PDA?
2 silk sutures 2-0
To avoid traumatizing the vessels, dissection should continue deeply, parallel to the ductus, before progressing cranially or caudally around it
tying each suture, beginning with the suture closest to the aorta
What is the Branham reflex?
Increase in blood pressure and decrease in HR after ligation of a PDA
What is the mortality rate of PDA ligation?
0-7%
outcome PDA
- Mortality rates approaching 0% are achievable by experienced surgeons
- curative in the majority of cases when it is performed at an early age (<6 months of age)
- Mitral regurgitation and secondary myocardial failure are generally reversible
- congestive heart failure increased the risk of postoperative mortality
- Secondary changes may not be entirely reversible in older animals > closure is still indicated in these animals because it will be associated with significant palliation
Rupture of the ductus arteriosus or great vessels
- risk of hemorrhage or perioperative death decreases with surgeon experience and increases in older animals
- Large ruptures must be controlled immediately with vascular clamps.
- Jackson-Henderson technique can be used in these cases to avoid direct passage of the forceps behind the medial side of the ductus.
- closed with three or four wide-biting buttressed mattress sutures across the ductus.
- divided between vascular clamps and oversewn
- aortic clamp tehcnique
complications
- mortality
- haemorrhage/rupture
- persistent shunting (Small amounts of residual flow are not unexpected)
pulmonic stenosis
- English Bulldogs, Chihuahuas
- Pulmonic stenosis causes pressure overload and concentric hypertrophy of the right ventricle.
List indications for surgery with pulmonic stenosis
What are the surgical options?
Indications for surgery:
- Tricuspid regurgitation
- Severe stenosis
- Systolic pressure gradient across defect of 60mmHg or more
- Clinical signs
Sx options:
- Dilatation valvuloplasty
- Pulmonic valvulotomy or valvulectomy
- Patch-graft valvuloplasty
When is balloon valvuloplasty for pulmonic stenosis contraindicated?
When there is a anomalous left coronary artery (common in Eng Bulldogs and Boxers)
What is the recommended approach for a patch graft valvuloplasty using inflow occlusion and cardiac bypass?
Inflow occlusion - left 5th intercostal
Bypass - median sternotomy
outcome
- Correction of pulmonic stenosis should be regarded as a palliative rather than curative procedure
- risk for sudden cardiac death likely diminishes but is not eliminated
- balloon dilatation valvuloplasty has been shown to reduce clinical sign
- Mortality rates for percutaneous balloon valvuloplasty are 10% or less
- patch-graft valvuloplasty performed during cardiopulmonary bypass, the perioperative mortality rate was 30%
What breeds are predisposed to aortic stenosis?
What is the classical murmur?
Newfies, Goldens, Boxers, Rottweilers, Bouviers
Crescendo-decrescendo left systolic murmur at the heart base
The pressure overload experienced by the left ventricle, secondary to the stenosis, leads to symmetric left ventricular hypertrophy.
What are the treatment options for aortic stenosis?
What factor effects survival?
Options:
- Surgical valvuloplasty
- Transcatheter balloon valvuloplasty
- Beta-blockers
- Tx does not effect survival….
Severity of pressure gradient effects survival
What are the surgial options for a ventricular septal wall defect?
- Pulmonary artery banding (increase right ventricular systolic pressure and thereby decrease the pressure gradient driving the shunt flow)
- Open repair
- Intravascular or hybrid intervention (Amplatz Ductal Occluder)
A large ventricular septal defect allows left-to-right shunting of blood that overloads the left (and possibly right) ventricle, resulting in progressive heart failure.
List the components of Tetralogy of Fallot
- Pulmonic stenosis
- Ventricular septal defect
- Overriding aorta
- Right ventricular hypertrophy
The most common cyanotic herat defect in companion animals
What breeds are overrepresented for Tetralogy of Fallot?
Keeshonds
Poodles
Schnauzers
Terriers
Collies
Shelties
What is the most prominent feature of tetralogy of fallot?
Moderate to severe cyanosis, unresponsive to supplemental oxygen
simplified into the combined effects of pulmonic stenosis and ventricular septal defect
What are the surgical indicators for tetralolgy of fallot?
Debilitating exercise intolerance
Polycythaemia (HCT over 70%)
Resting hypoxaemia (arterial saturation less than 60%)
What are the surgical options for tetralogy of fallot?
Systemic-to-pulmonic shunts to increase pulmonary blood flow
- Blalock-Taussig (Subclavian to pulmonary artery)
- Potts (Aorticopulmonary anastomosis)
- Waterston (aorta-to-right pulmonary artery)
- Glenn (Venocaval-to-pulmonary artery anastomosis)
Open repair
- Patch closure of VSD
- Oval patch graft valvuloplasty for pulmonary stenosis
What is cor triatriatum?
What are the two main types?
An uncommon congenital defects resulting in the persistance of an embryonic membrane
- Cor triatriatum dexter - on the right. Chow chows overrepresented
- Cor triatriatum sinister - on the left, reported in cats
Causes obstruction of venous flow through the atrium.
Membranectomy considered curative
mitral valve dz
- Myxomatous degeneration is the most frequent cause
- Congenital mitral valve dysplasia occurs in cats and several large and giant breeds of dog
- may also occur secondary to dilated cardiomyopathy
Mitral regurgitation causes volume overload of the left heart, resulting in hypertrophy and dilatation of the left atrium and ventricle.
What is a relative contraindication for mitral valve surgery?
Severe chronic inflammatory airway disease with or without collapsing trachea
List the surgical options for mitral regurgitation
Mitral valve replacement through 5th right or left thoracotomy
Mitral valve repair
What are indications for a pacemaker?
High-grade 2nd or 3rd degree AV blocks (not repsonsive to atropine)
Sick sinus syndrome
Sinus arrest
Chronic bradyarrhythmias
*Sympathomimetic or vagolytic agents improve conduction through the AVN by reducing vagal tone via muscarinic receptor blockade. *
causes bradycardia
What are the 2 methods of pacemaker insertion?
Transveonous (preferred)
Epicardial (may be necessary in small dogs and cats)
Describe the 5 letts NASPE/BPEG coding of pacemakers
What is the most common pacing mode of vet patients?
letters indicate the chamber paced, the chamber sensed, the response to sensing, whether the rate can be modulated, and wheter the system provided multisite pacing
Chambers paced, chambers sensed and multisite pacing are identified using:
- A - atrium
- V - ventricle
- D - dual
- O - none
Response to sensing:
- T - triggered
- I - inhibited
- D - dual
- O - none
Rate of modulation:
- R - present
- O - absent
Most common is single-chamber ventricular inhibited synchronous pacing with (VVIR) or without (VVI) rate modulation
What is the recommended approach for an epicardial pacemaker?
5th or 6th left lateral thoracotomy
Regarding pacemakers, what may be the cause of an increase in impedence of large variations in impedence and failure to pace?
Increase: development of excessive inflammatory tissue around the lead tip
Variation: Lead instability
Failure to pace: lead breakage, disconnection or dislodgement
methods for fixation of epicardial leads?
- Current available methods for fixation of epicardial leads include passive and active fixations.
- With active fixation, the lead has a screw-type end that penetrates the myocardium of the left ventricle.
- A passive fixation lead terminates with a button-like ending that is applied to the surface of the epicardium and sutured in place
Cardiac Neoplasia (10)
hemangiosarcoma,
fibrosarcoma,
chondrosarcoma,
rhabdomyosarcoma,
ectopic thyroid carcinoma,
fibroma,
myxoma,
chemodectoma
Lymphosarcoma (cats)
metastatic neoplasia (cats)
What breeds are predisposed to cardiac HSA?
What percentage will have concurrent HSA of the spleen?
Mets to other areas?
most common presentation?
often from the right atrial wall + pericardial effusion
- GSD, Goldens and Labs
- 29% HSA in spleen
- 42% mets in other areas
With primary splenic HSA, 8.7% will have a cardiac mass
acute cardiac tamponade resulting from intrapericardial hemorrhage
40% to 69% = most common cardiac neoplasia in dogs
What is the prognosis for cardiac HSA?
- Surgical excision - 4m
- Longer with adjuvant chemo
- Pericardiectomy alone does not improve survival (without removal of mass)
Heart-Base Tumors
- chemodectoma (Aortic body tumors 80%)
- ectopic thyroid carcinoma
- parathyroid masses
between the outer wall of the ascending aorta and surrounding cardiac structures
presumptive diagnosis of aortic body tumor can be made based on this typical location
Aortic body tumors
- highly vascular, slow growing, and moderately locally invasive
- can grow into cardiac chambers, resulting in obstruction
- can also cause pericardial effusion
- Many are discovered incidentally
Sx
- inherent risks associated with surgery (i.e., bleeding and vagal nerve injury)
- there is little evidence that surgical removal is beneficial
- Pericardiectomy prolongs survival in dogs (should be considered paaliative
Why are brachycephalic dogs thought to be predisposed to chemodectomas?
Chronic stimulation of the chemoreceptors by hypoxia
What is the prognosis for chemodectoma?
Pericardiectomy 730d (vs 42d without)
Other Neoplastic Conditions
Mesothelioma of the pericardium and pleura has been reported with increasing frequency.96 Discrete masses may form, particularly at the heart base, and are visible on echocardiography
Epicardial pacemaker placement is associated with low complication rate and improved quality of life in dogs
Matteo Rossanese 2024
52 client-owned dogs, retro
Third-degree atrioventricular block (39/52 [75%])
Intra- and postoperative complications were documented in 11% and 23%
Overall, 96% of dogs survived to discharge,
Presence of coexistent myocardial or valvular disease reduced survival.
1 dog developed refractory ventricular fibrillation and died intraoperatively
4 dogs required only adjustment of the PM settings, whereas 5 dogs required a surgical intervention including placement of a transvenous PM due to lead displacement (n = 3), replacement of the PM leads due to lead fracture (1), and replacement of the generator (1).
Epicardial pacemakers were implanted by use of an abdominal transdiaphragmatic approach in 47 dogs and a left lateral intercostal thoracotomy in 5 dogs
Effects of mitral valve repair on valvular geometry
and hemodynamics in dogs with myxomatous
mitral valve disease
Kippei Mihara 2024
Study design: Retrospective cohort study.
Sample population: Dogs (n = 77)
Mitral valve repair changed valvular geometry and improved
hemodynamics as assessed by follow-up echocardiography
Mitral valve repair is
reportedly a more attractive option than valve replacement
for achieving functional restoration, having shown
superior efficacy for endpoints such as cardiac function, prevention
of thrombi formation, and durability in human.6,7
Mitral valve repair is becoming more widely performed in
canine medicine
questions needing to be
further addressed include how to repair the annulus
diameter, how to determine the length of the artificial
chordae tendineae, and how to observe the mitral valve
geometry and function during the peri- and postoperative
periods
Sx
- To create artificial chordae tendineae, several bridges of CV6 30-inch ePTFE sutures, which
were passed through the loop or slits in the knots of the anchor sutures, were built between the edge of the prolapsed leaflets and the anchor
on the corresponding papillary muscle.
Mitral
annuloplasty was performed by shortening the parietal annulus with a CV5 30-inch ePTFE suture
Intensity-modulated radiotherapy and chemotherapy for
canine right atrial tumors: A retrospective study of seven dogs
Steven Moirano1
VRU
One dog had a complete response, four dogs had partial responses and
two dogs had stable disease after treatment. Effusions resolved in all dogs. Median
progression-free survival was 290 days. Median overall survival was 326 days.
Beta-adrenergic receptor
antagonists, such as propranolol, are used for treating hemangiomas
of infancy and have shown cytotoxicity and tumor suppressive ability
against malignant human vascular tumors.6 Moreover, propranolol
combined with vinblastine was shown to synergistically decrease the
proliferation of canine HSA cell lines
right atrial tumors treated with a multimodal protocol
involving intensity-modulated radiotherapy (IMRT) and concurrent
chemotherapy.
Risk factors for intraoperative hemorrhage and perioperative complications and short- and long-term outcomes
during surgical patent ductus arteriosus ligation in 417 dogs
McNamara 2023
There was no association between age and risk of intraoperative hemorrhage (P = .7), weight and intraoperative hemorrhage (P = .96), or increasing left atrium-to-aortic (LA:Ao) ratio and intraoperative hemorrhage (P = .08). Intraoperative hemorrhage occurred in 10.8% of patients. Intraoperative mortality was 2%. Ninety-five percent of dogs experiencing intraoperative hemorrhage survived to discharge. Survival to discharge was 97%. One- and 5-year survival rates were 96.4% and 87%, respectively
median age was 10.3 months (range, 1 to 108 months
42 (10%) had a history of left-sided CHF and 59 (14%) had evidence of left-sided CHF at the time of presentation. Eighty-six (21%) dogs were receiving cardiac medications at the time of presentation,
complications
146 dogs (80.2%) had anesthetic-related complications,
4 (2.2%) dogs suffered cardiopulmonary arrest, 27 (14.8%) dogs had arrhythmias, and 4 (2.2%) dogs had a prolonged anesthetic recovery.
Out of the 417 patients undergoing surgery, intraoperative hemorrhage occurred in 45 (11%) patients and 20 (5%) dogs required a blood transfusion during surgery
hemostasis included placement of hemoclips (22%), conversion to a Jackson-Henderson approach (16%), and use of Gelfoam in 1 patient. Of the 45 patients experiencing hemorrhage, 5 were euthanized or died due to persistent bleeding.
overall intraoperative mortality rate was 2.2% (9/417), with 4 of the 9 (44%) dogs dying from cardiac arrest and 5 (56%) dogs dying or being euthanized due to uncontrollable hemorrhage
good long-term prognosis.
Certain preoperative factors such as age, weight, and the presence and degree of mitral valve regurgitation had no detectable association with risks of intraoperative hemorrhage and, therefore, should not preclude surgical treatment for a left-to-right shunting PDA.
Future studies are needed to further assess the association between increasing LA:Ao ratio and risk of intraoperative hemorrhage.
Use of the Functional Evaluation of Cardiac Health questionnaire to assess health-related quality of life before and after mitral valve repair in dogs
with myxomatous mitral valve disease
Pennington 2022
left-sided congestive heart failure can develop in some dogs. This is ultimately fatal, with reported survival times of < 1 year with medical management alone.
All dogs were prescribed a 3-month course of aspirin and clopidogrel following MVR
By T12, 30 of the 40 dogs (75%) for which follow-up information was available were receiving no medications, and 8 (20%) were receiving only pimobendan.
Two (3.7%) dogs were found to have rupture of ≥ 1 artificial chord postoperatively
Three (5.5%) dogs experienced complications suspected to be related to emboli during the hospitalization period.
Surgical ligation of patent ductus arteriosus in dogs:
Incidence and risk factors for rupture
Janet A. Grimes 2021
Retrospective cohort.
Animals: Two-hundred and eighty-five dogs
Rupture of the
PDA occurred in 7.0% of dogs (20/285, 13 extrapericardial, 3 intrapericardial,
4 not reported). No difference in age or weight was found between dogs with
and without rupture. Overall mortality was 0.4% (1/285).
The overall
rate of residual flow after ligation was 9.4%.
Successful treatment of PDA rupture is possible,
evidenced by the low mortality rate in this population of dogs. Ligation of the
PDA after rupture, either in the concurrent or a subsequent procedure, reduces
the odds of residual flow.
Surgical ligation is recommended over transarterial
occlusion when the patient is too small or the shape of
the PDA is not amenable to transarterial procedures
Major complications associated with surgical ligation
of PDAs are reported to occur in 6% to15% of dogs
and include rupture of the PDA with subsequent hemorrhage,
lung trauma, residual flow through the PDA,
and cardiac arrest associated with closure
Major complications associated with transarterial proce dures are reported to occur in 0% to 4%
Reported mortality rates with surgical
ligation range from 0% to 6%,2,5–7 whereas
mortality rates with transarterial procedures range from 0% to 3%.2,7,10
hemostasis without
ligation was accomplished by a combination of digital
pressure (3), vascular clips (3), topical hemostatic agent
use (2), and suture of a visible defect in the PDA (1)
Surgical treatment of persistent right aortic arch with
combined ligamentum arteriosum transection and
esophageal diverticulum resection in three dogs
Nicholas J. Olson2021
monnet
Resection of esophageal diverticulum secondary to PRAA utilizing
a TA stapler with suture overlay was technically feasible and did not seem
associated with early or late complications.
Complications during catheter-mediated patent ductus arteriosus closure and pulmonary balloon valvuloplasty
claretti 2019
Five hundred and twenty-four dogs were included, 62 of which had complications.
four dogs died during the interventional procedure, indicating a mortality rate of 0.76%
The most frequent overall complications were that the
ACDO device dimensions were inappropriate for MDD (nine of
32), vagal reflex (six of 32) and unusual morphology of the PDA
(four of 32). Bleeding
Pulmonary artery banding in a cat
with a perimembranous ventricular septal defect
and left-sided congestive heart failure
Brandy N. Cichocki 2019
During surgery, blood pressure in the pulmonary
artery was measured with a pulmonary artery catheter, and pulmonary
artery banding was successfully achieved with a polytetrafluoroethylene
band and hemoclips. The pulmonary-to-systemic blood flow ratio was
reduced from 3 to 1.5, and signs of congestive heart failure resolved within
2 weeks after surgery
pulmonary-to-systemic flow
ratio > 3 or with congestive heart failure attributable to a VSD could be
considered candidates for palliative pulmonary artery banding
Comparison of major complication and survival rates
between surgical ligation and use of a canine ductal
occluder device for treatment of dogs with left-to-right
shunting patent ductus arteriosus
Bharadhwaj Ranganathan 2018
Retrospective cohort study.
ANIMALS
120 client-owned dogs with left-to-right shunting PDA (62 treated by SL
and 58 treated by CDO implantation).
Dogs treated by CDO implantation were significantly older and heavier
Durations of anesthesia and surgery
were also significantly longer for CDO implantation versus SL. The
major complication rate for dogs treated by SL (6/62 [10%]) was significantly
greater than that for dogs treated by CDO implantation (0/58 [0%]).
One dog in the SL group died during surgery. Overall rate of survival to
hospital discharge was 99% (119/120).
Although a greater proportion of dogs had major complications
during the SL procedure, the 2 procedures had comparable rates
of survival to hospital discharge.
The higher intraoperative complication
rate associated with SL and the limitations
of CDO device sizing should be considered when
choosing a treatment method for a dog with PDA.
Retrospective comparison of short-term outcomes
following thoracoscopy versus thoracotomy for surgical
correction of persistent right aortic arch in dogs
Daniel J. Nucci 2018
30 dogs
Dogs underwent a thoracotomy alone (n = 15), thoracoscopy alone (10), or
thoracoscopy converted to thoracotomy (5) for treatment of PRAA. Median
duration of surgery was not markedly different among groups, nor was
the incidence of postoperative complications or median amount of time a
thoracostomy tube was maintained in place.
Median duration of hospitalization
was 1 day (range, 0.5 to 2 days) for dogs that underwent thoracoscopy
and 2 days (range, 0.5 to 22 days) for dogs that underwent thoracotomy
Greet 2021 – clinical features/outcome for bidirectional and continuous right-to-left shunting
- presentation: dogs: hindlimb collapse most common; cats: variable
- MST: dogs: 626d – R-CHF → shorter MST (58d vs 1839)
sildenafil treatment at presentation → longer survival (1839 vs 302d)
- only independent predictor of survival
- 6 surgical closure attempted, 5/6 pre-treated with sildenafil → 3 deaths, 3 good long-term
