BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors nonprofit publishers academic institutions researchlibraries and research funders in the common goal of maximizing access to critical research

PERSISTENT RIGHT AORTIC ARCH AND ABERRANT LEFT SUBCLAVIANARTERY IN A WHITE BENGAL TIGER (PANTHERA TIGRIS)Author(s) Cornelia J KetzDVM MaryAnn RadlinskyDVM MS Laura ArmbrustDVM James WCarpenterDVM MS and Ramiro IsazaDVM MSSource Journal of Zoo and Wildlife Medicine 32(2)268-272 2001Published By American Association of Zoo VeterinariansDOI httpdxdoiorg1016381042-7260(2001)032[0268PRAAAA]20CO2URL httpwwwbiooneorgdoifull1016381042-7260282001290325B02683APRAAAA5D20CO3B2

BioOne (wwwbiooneorg) is a nonprofit online aggregation of core research in the biological ecological andenvironmental sciences BioOne provides a sustainable online platform for over 170 journals and books publishedby nonprofit societies associations museums institutions and presses

Your use of this PDF the BioOne Web site and all posted and associated content indicates your acceptance ofBioOnersquos Terms of Use available at wwwbiooneorgpageterms_of_use

Usage of BioOne content is strictly limited to personal educational and non-commercial use Commercial inquiriesor rights and permissions requests should be directed to the individual publisher as copyright holder

268

Journal of Zoo and Wildlife Medicine 32(2) 268ndash272 2001Copyright 2001 by American Association of Zoo Veterinarians

PERSISTENT RIGHT AORTIC ARCH AND ABERRANT LEFTSUBCLAVIAN ARTERY IN A WHITE BENGAL TIGER(PANTHERA TIGRIS)

Cornelia J Ketz DVM MaryAnn Radlinsky DVM MS Laura Armbrust DVMJames W Carpenter DVM MS and Ramiro Isaza DVM MS

Abstract A 3-mo-old male white Bengal tiger (Panthera tigris) presented with the chief complaint of regurgitationof solid food since weaning at 2 mo of age Compared with its littermates the tiger was in poor body condition andweighed only 103 kg when its littermates were estimated at 20ndash25 kg Thoracic radiographs showed a megaesophaguscranial to the heart base A contrast esophagram more clearly outlined the megaesophagus and fluoroscopy demon-strated normal motility of the caudal esophagus Endoscopic examination revealed a structure coursing dorsally fromright to left over the esophagus and a constrictive band on the left of the esophagus at the heart base Nonselectiveangiography confirmed the presence of a persistent right aortic arch as well as an aberrant left subclavian artery Aleft fourth intercostal thoracotomy was performed and the ligamentum arteriosum was double ligated and divided Theleft subclavian artery did not cause significant compromise of the esophagus and was not manipulated at surgery Thetiger recovered well from anesthesia and surgery Solid food was slowly introduced over a 2-mo period without anyregurgitation The cub gained weight rapidly after surgery

Key words White Bengal tiger Panthera tigris persistent right aortic arch left aberrant subclavian artery mega-esophagus angiography

BRIEF COMMUNICATION

A 3-mo-old male white Bengal tiger (Pantheratigris) was referred to the Kansas State UniversityVeterinary Medical Teaching Hospital for chronicregurgitation The animal developed difficultyswallowing with concurrent regurgitation of milk at4 wk of age The problem worsened when the tigerwas started on solid food at 2 mo of age An intes-tinal blockage and obstruction caused by a foreignbody were ruled out by the referring veterinarianHe also confirmed the diagnosis of a vascular ringanomaly with radiographs and a contrast esopha-gram

On presentation at Kansas State University thetiger was in poor body condition and weighed 103kg whereas his unaffected littermates weighed ap-proximately 20ndash25 kg A complete blood count(CBC) and serum biochemical profile of the bloodwere within normal limits The tiger was sedatedwith acepromazine (Acepromazine Fermenta Ani-mal Health Co Kansas City Missouri 64153USA 008 mgkg im) for further diagnostics Re-peat survey radiographs and esophagram demon-strated megaesophagus cranial to the heart basewith a normal caudal esophagus (Fig 1A B)

The following day the tiger was premedicated

From the Department of Clinical Sciences College ofVeterinary Medicine Kansas State University ManhattanKansas 66506 USA Present address (Ketz) OklahomaCity Zoological Park 2101 NE 50th Oklahoma CityOklahoma 73111 USA Correspondence should be di-rected to Dr Ketz

with midazolam (Versedt Roche Pharma ManatiPuerto Rico 00674 02 mgkg im) oxymorphone(Numorphant Du Pont Pharma Wilmington Del-aware 19880 USA 007 mgkg im) and atropine(Atropine Phoenix Scientific Inc St Joseph Mis-souri 64506 USA 004 mgkg im) Anesthesiawas induced with isoflurane (Isoflot Abbott Lab-oratories North Chicago Illinois 60064 USA) at4 in oxygen via face mask and maintained withisoflurane in oxygen after endotracheal intubationEsophagoscopy revealed a mildly compressive pul-sating structure coursing dorsally over the esopha-gus from right to left in a caudal-to-cranial direc-tion Severe constriction to the left of the esophaguswas present at the heart base (Fig 2) These find-ings were consistent with a persistent right aorticarch (PRAA) and a left ligamentum arteriosum con-stricting the esophagus Additionally an aberrantleft subclavian artery was suspected Nonselectiveangiography was performed through a jugular cath-eter with 125 ml iohexol a nonionic iodinatedcontrast media (Omnipaquet 240 Nycomed IncPrinceton New Jersey 08540 USA) Initially 025mlkg was bolused intravenously and timing ofmaximum contrast visualized in the aorta was de-termined by fluoroscopy Two subsequent iohexolboluses of 025 mlkg each were administered forthe lateral and the ventrodorsal radiographs Thisstudy confirmed both a dextroposition of the aorticarch and an anomolous left subclavian artery (Fig3A B)

A standard left fourth intercostal thoracotomywas performed A PRAA and an aberrant left sub-

269KETZ ET ALmdashVASCULAR ANOMALY IN A TIGER

Figure 1 Right lateral (A) and ventrodorsal (B) thoracic radiographs of a white Bengal tiger (Panthera tigris)obtained during a positive-contrast esophageal study Note dilation of the esophagus cranial to the base of the heart atthe level of the descending aorta The intrathoracic trachea is deviated ventrally as a result of the esophageal dilation

clavian artery with a left ligamentum arteriosumformed a ring around the esophagus and tracheaThe ligamentum arteriosum was isolated double li-gated with 2-0 silk and transected Numerous fi-brous adhesions around the esophagus were debrid-ed Lack of esophageal constriction was confirmed

upon passage of an orogastric tube The aberrantleft subclavian artery was not manipulated becauseit did not cause significant compromise of theesophagus

The tiger recovered well from anesthesia and wasgiven oxymorphone 005 mgkg im for pain relief

270 JOURNAL OF ZOO AND WILDLIFE MEDICINE

Figure 2 Partial obstruction of the esophagus of a white Bengal tiger (Panthera tigris) observed during endoscopyof the esophagus The open arrow represents the lumen of the esophagus The black arrow represents the aberrantsubclavian artery The arrowheads outline the ligametum arteriosum

twice during the first 12 hr after surgery The ani-mal exhibited an excellent appetite when offeredsmall amounts of 3-cm pieces of canned cat foodafter surgery Neither regurgitation nor respiratoryproblems developed The owners fed the tiger 3ndash5-cm meatballs of canned cat food from an elevatedbowl for the next 2 wk Canned food was then of-fered in normal portions with forequarter elevationMuscle meat was gradually added to the diet overa 2-mo period Eventually the tiger was eatinghorse and beef meat mixed with a meat-based com-mercial diet and no longer required elevated feed-ings The tiger grew rapidly and 1 yr later theowners reported the tiger to be over 150 kg andeating normally

DISCUSSION

During embryogenesis the ventral and dorsalaortas are connected by six pairs of aortic arches9

The ventral aortas form the heart whereas the dor-sal aortas fuse to become the descending aorta The

first two pairs of aortic arches degenerate early dur-ing ontogenesis The third arches form the internalcarotid arteries and the right fourth arch becomesthe right subclavian artery The left fourth archforms the aortic arch The fifth arches regress Thesixth arches form the pulmonary arteries The seg-ment of the left sixth arch distal to the pulmonaryartery persists as the ductus arteriosus Vascularring anomalies occur when aortic arches IV and VIdevelop abnormally9 Anomalies of the third archesdo not result in a vascular ring formation aroundthe trachea or esophagus

Vascular ring anomaly caused by a PRAA andleft ligamentum arteriosum is the most commoncongenital vascular defect in domestic dogs andcats13ndash5 Vascular ring anomalies have been identi-fied in two nondomestic felids a mountain lion(Felis concolor) and a white lion (Panthera leo)26

This white tiger cub showed poor developmentand regurgitation at weaning both typical signs ofvascular ring anomaly The diagnosis of vascular

271KETZ ET ALmdashVASCULAR ANOMALY IN A TIGER

Figure 3 Right lateral and ventrodorsal radiographs of a white Bengal tiger (Panthera tigris) obtained duringnonselective angiography Mild aneurysmal dilation of the descending aorta (white arrows) present at the level ofcontrast material stoppage during the esophagram (A) The ventrodorsal radiograph with dextropositioning of the aorta(black arrowheads) An aberrant vessel is coursing toward the left forelimb consistent with the left subclavian artery(white arrows) (B)

272 JOURNAL OF ZOO AND WILDLIFE MEDICINE

ring anomaly was confirmed by radiography con-trast studies of the esophagus esophagoscopy fluo-roscopy and nonselective angiography The leftsubclavian artery probably originated from the leftseventh intersegmental artery rather than the leftfourth aortic arch because the aberrant vesselcoursed dorsal to the esophagus Therefore twocompressions could be observed a mild compres-sion from the aberrant left subclavian artery and asevere constriction due to the ligamentum arterios-um In this case ligature of the left subclavian ar-tery was not performed because of the lack of acomplete ring at the site and the risk of compromiseof the circulation to the left forelimb

Whether genetic or hemodynamic factors lead tothe development of vascular ring anomalies is un-known In dogs evidence of a hereditary basisleading to PRAA has been documented57 WhiteBengal tigers are significantly inbred8 Because agenetic cause for the development of the PRAA andthe left aberrant subclavian artery in this tiger can-not be eliminated we strongly recommendedagainst future breeding of this tiger

Acknowledgments We acknowledge Dr DonaldMayfield for referring the tiger Drs Julie Fisherand Susan Kraft for assistance in the diagnosticworkup and Drs Rose McMurphy and DavidHodgson for assistance with anesthesia

LITERATURE CITED

1 Fox P R 1988 Congenital feline heart disease InFox P R (ed) Canine and Feline Cardiology ChurchillLivingstone Inc New York New York Pp 404ndash408

2 Goldin J P and N E Lambrechts 1999 Doubleaortic arch and persistent left vena cava in a white lioncub (Panthera leo) J Zoo Wildl Med 30 145ndash150

3 Hurley K M W Miller M D Willard and H WBoothe 1993 Left aortic arch and right ligamentum ar-teriosum causing esophageal obstruction in a dog J AmVet Med Assoc 203 410ndash412

4 Jeffrey S C N Bataller R A Martin and M LMoon 1995 Postsurgical nutritional management ofmegaesophagus secondary to persistent right aortic archin a kitten Feline Pract 23 17ndash23

5 Mudoon M M S J Birchard and G W Ellison1997 Long term results of surgical corrections of persis-tent right aortic arch in dogs 25 cases (1980ndash1995) JAm Vet Med Assoc 210 1761ndash1763

6 Rochat M C and E S Settles 1993 Persistentright aortic arch in a cougar (Felis concolor) J ZooWildl Med 24 534ndash538

7 Shires P K and W Liu 1981 Persistent right aorticarch in dogs a long term follow-up after surgical correc-tion J Am Anim Hosp Assoc 17 773ndash776

8 Thornton I W B 1978 White tiger geneticsmdashfur-ther evidence J Zool 185 389ndash394

9 Wysong R L 1969 Embryology of persistent rightaortic arch Vet Med Sm Anim Clin March 1969 204ndash209

Received for publication 27 June 2000

ERRATA

Infectious and Parasitic Diseases and Contaminant-Related Problems of North American River Otters (Lontra cana-densis) A Review KEVIN R KIMBER and GEORGE V KOLLIAS JZWM v 31 (4)454ndash472

Page 466 1st paragraph final sentence should read lsquolsquoNumerous studies throughout North America have shownan association between high concentrations of contaminants and disease or population declines in L canaden-sis145862135169170 Studies showing causal links between exposure and disease in L canadensis are uncommonrsquorsquo107108

269KETZ ET ALmdashVASCULAR ANOMALY IN A TIGER

Figure 1 Right lateral (A) and ventrodorsal (B) thoracic radiographs of a white Bengal tiger (Panthera tigris)obtained during a positive-contrast esophageal study Note dilation of the esophagus cranial to the base of the heart atthe level of the descending aorta The intrathoracic trachea is deviated ventrally as a result of the esophageal dilation

clavian artery with a left ligamentum arteriosumformed a ring around the esophagus and tracheaThe ligamentum arteriosum was isolated double li-gated with 2-0 silk and transected Numerous fi-brous adhesions around the esophagus were debrid-ed Lack of esophageal constriction was confirmed

upon passage of an orogastric tube The aberrantleft subclavian artery was not manipulated becauseit did not cause significant compromise of theesophagus

The tiger recovered well from anesthesia and wasgiven oxymorphone 005 mgkg im for pain relief

270 JOURNAL OF ZOO AND WILDLIFE MEDICINE

Figure 2 Partial obstruction of the esophagus of a white Bengal tiger (Panthera tigris) observed during endoscopyof the esophagus The open arrow represents the lumen of the esophagus The black arrow represents the aberrantsubclavian artery The arrowheads outline the ligametum arteriosum

twice during the first 12 hr after surgery The ani-mal exhibited an excellent appetite when offeredsmall amounts of 3-cm pieces of canned cat foodafter surgery Neither regurgitation nor respiratoryproblems developed The owners fed the tiger 3ndash5-cm meatballs of canned cat food from an elevatedbowl for the next 2 wk Canned food was then of-fered in normal portions with forequarter elevationMuscle meat was gradually added to the diet overa 2-mo period Eventually the tiger was eatinghorse and beef meat mixed with a meat-based com-mercial diet and no longer required elevated feed-ings The tiger grew rapidly and 1 yr later theowners reported the tiger to be over 150 kg andeating normally

DISCUSSION

During embryogenesis the ventral and dorsalaortas are connected by six pairs of aortic arches9

The ventral aortas form the heart whereas the dor-sal aortas fuse to become the descending aorta The

first two pairs of aortic arches degenerate early dur-ing ontogenesis The third arches form the internalcarotid arteries and the right fourth arch becomesthe right subclavian artery The left fourth archforms the aortic arch The fifth arches regress Thesixth arches form the pulmonary arteries The seg-ment of the left sixth arch distal to the pulmonaryartery persists as the ductus arteriosus Vascularring anomalies occur when aortic arches IV and VIdevelop abnormally9 Anomalies of the third archesdo not result in a vascular ring formation aroundthe trachea or esophagus

Vascular ring anomaly caused by a PRAA andleft ligamentum arteriosum is the most commoncongenital vascular defect in domestic dogs andcats13ndash5 Vascular ring anomalies have been identi-fied in two nondomestic felids a mountain lion(Felis concolor) and a white lion (Panthera leo)26

This white tiger cub showed poor developmentand regurgitation at weaning both typical signs ofvascular ring anomaly The diagnosis of vascular

271KETZ ET ALmdashVASCULAR ANOMALY IN A TIGER

Figure 3 Right lateral and ventrodorsal radiographs of a white Bengal tiger (Panthera tigris) obtained duringnonselective angiography Mild aneurysmal dilation of the descending aorta (white arrows) present at the level ofcontrast material stoppage during the esophagram (A) The ventrodorsal radiograph with dextropositioning of the aorta(black arrowheads) An aberrant vessel is coursing toward the left forelimb consistent with the left subclavian artery(white arrows) (B)

272 JOURNAL OF ZOO AND WILDLIFE MEDICINE

ring anomaly was confirmed by radiography con-trast studies of the esophagus esophagoscopy fluo-roscopy and nonselective angiography The leftsubclavian artery probably originated from the leftseventh intersegmental artery rather than the leftfourth aortic arch because the aberrant vesselcoursed dorsal to the esophagus Therefore twocompressions could be observed a mild compres-sion from the aberrant left subclavian artery and asevere constriction due to the ligamentum arterios-um In this case ligature of the left subclavian ar-tery was not performed because of the lack of acomplete ring at the site and the risk of compromiseof the circulation to the left forelimb

Whether genetic or hemodynamic factors lead tothe development of vascular ring anomalies is un-known In dogs evidence of a hereditary basisleading to PRAA has been documented57 WhiteBengal tigers are significantly inbred8 Because agenetic cause for the development of the PRAA andthe left aberrant subclavian artery in this tiger can-not be eliminated we strongly recommendedagainst future breeding of this tiger

Acknowledgments We acknowledge Dr DonaldMayfield for referring the tiger Drs Julie Fisherand Susan Kraft for assistance in the diagnosticworkup and Drs Rose McMurphy and DavidHodgson for assistance with anesthesia

LITERATURE CITED

1 Fox P R 1988 Congenital feline heart disease InFox P R (ed) Canine and Feline Cardiology ChurchillLivingstone Inc New York New York Pp 404ndash408

2 Goldin J P and N E Lambrechts 1999 Doubleaortic arch and persistent left vena cava in a white lioncub (Panthera leo) J Zoo Wildl Med 30 145ndash150

3 Hurley K M W Miller M D Willard and H WBoothe 1993 Left aortic arch and right ligamentum ar-teriosum causing esophageal obstruction in a dog J AmVet Med Assoc 203 410ndash412

4 Jeffrey S C N Bataller R A Martin and M LMoon 1995 Postsurgical nutritional management ofmegaesophagus secondary to persistent right aortic archin a kitten Feline Pract 23 17ndash23

5 Mudoon M M S J Birchard and G W Ellison1997 Long term results of surgical corrections of persis-tent right aortic arch in dogs 25 cases (1980ndash1995) JAm Vet Med Assoc 210 1761ndash1763

6 Rochat M C and E S Settles 1993 Persistentright aortic arch in a cougar (Felis concolor) J ZooWildl Med 24 534ndash538

7 Shires P K and W Liu 1981 Persistent right aorticarch in dogs a long term follow-up after surgical correc-tion J Am Anim Hosp Assoc 17 773ndash776

8 Thornton I W B 1978 White tiger geneticsmdashfur-ther evidence J Zool 185 389ndash394

9 Wysong R L 1969 Embryology of persistent rightaortic arch Vet Med Sm Anim Clin March 1969 204ndash209

Received for publication 27 June 2000

ERRATA

Infectious and Parasitic Diseases and Contaminant-Related Problems of North American River Otters (Lontra cana-densis) A Review KEVIN R KIMBER and GEORGE V KOLLIAS JZWM v 31 (4)454ndash472

Page 466 1st paragraph final sentence should read lsquolsquoNumerous studies throughout North America have shownan association between high concentrations of contaminants and disease or population declines in L canaden-sis145862135169170 Studies showing causal links between exposure and disease in L canadensis are uncommonrsquorsquo107108

270 JOURNAL OF ZOO AND WILDLIFE MEDICINE

Figure 2 Partial obstruction of the esophagus of a white Bengal tiger (Panthera tigris) observed during endoscopyof the esophagus The open arrow represents the lumen of the esophagus The black arrow represents the aberrantsubclavian artery The arrowheads outline the ligametum arteriosum

twice during the first 12 hr after surgery The ani-mal exhibited an excellent appetite when offeredsmall amounts of 3-cm pieces of canned cat foodafter surgery Neither regurgitation nor respiratoryproblems developed The owners fed the tiger 3ndash5-cm meatballs of canned cat food from an elevatedbowl for the next 2 wk Canned food was then of-fered in normal portions with forequarter elevationMuscle meat was gradually added to the diet overa 2-mo period Eventually the tiger was eatinghorse and beef meat mixed with a meat-based com-mercial diet and no longer required elevated feed-ings The tiger grew rapidly and 1 yr later theowners reported the tiger to be over 150 kg andeating normally

DISCUSSION

During embryogenesis the ventral and dorsalaortas are connected by six pairs of aortic arches9

The ventral aortas form the heart whereas the dor-sal aortas fuse to become the descending aorta The

first two pairs of aortic arches degenerate early dur-ing ontogenesis The third arches form the internalcarotid arteries and the right fourth arch becomesthe right subclavian artery The left fourth archforms the aortic arch The fifth arches regress Thesixth arches form the pulmonary arteries The seg-ment of the left sixth arch distal to the pulmonaryartery persists as the ductus arteriosus Vascularring anomalies occur when aortic arches IV and VIdevelop abnormally9 Anomalies of the third archesdo not result in a vascular ring formation aroundthe trachea or esophagus

Vascular ring anomaly caused by a PRAA andleft ligamentum arteriosum is the most commoncongenital vascular defect in domestic dogs andcats13ndash5 Vascular ring anomalies have been identi-fied in two nondomestic felids a mountain lion(Felis concolor) and a white lion (Panthera leo)26

This white tiger cub showed poor developmentand regurgitation at weaning both typical signs ofvascular ring anomaly The diagnosis of vascular

271KETZ ET ALmdashVASCULAR ANOMALY IN A TIGER

Figure 3 Right lateral and ventrodorsal radiographs of a white Bengal tiger (Panthera tigris) obtained duringnonselective angiography Mild aneurysmal dilation of the descending aorta (white arrows) present at the level ofcontrast material stoppage during the esophagram (A) The ventrodorsal radiograph with dextropositioning of the aorta(black arrowheads) An aberrant vessel is coursing toward the left forelimb consistent with the left subclavian artery(white arrows) (B)

272 JOURNAL OF ZOO AND WILDLIFE MEDICINE

ring anomaly was confirmed by radiography con-trast studies of the esophagus esophagoscopy fluo-roscopy and nonselective angiography The leftsubclavian artery probably originated from the leftseventh intersegmental artery rather than the leftfourth aortic arch because the aberrant vesselcoursed dorsal to the esophagus Therefore twocompressions could be observed a mild compres-sion from the aberrant left subclavian artery and asevere constriction due to the ligamentum arterios-um In this case ligature of the left subclavian ar-tery was not performed because of the lack of acomplete ring at the site and the risk of compromiseof the circulation to the left forelimb

Whether genetic or hemodynamic factors lead tothe development of vascular ring anomalies is un-known In dogs evidence of a hereditary basisleading to PRAA has been documented57 WhiteBengal tigers are significantly inbred8 Because agenetic cause for the development of the PRAA andthe left aberrant subclavian artery in this tiger can-not be eliminated we strongly recommendedagainst future breeding of this tiger

Acknowledgments We acknowledge Dr DonaldMayfield for referring the tiger Drs Julie Fisherand Susan Kraft for assistance in the diagnosticworkup and Drs Rose McMurphy and DavidHodgson for assistance with anesthesia

LITERATURE CITED

1 Fox P R 1988 Congenital feline heart disease InFox P R (ed) Canine and Feline Cardiology ChurchillLivingstone Inc New York New York Pp 404ndash408

2 Goldin J P and N E Lambrechts 1999 Doubleaortic arch and persistent left vena cava in a white lioncub (Panthera leo) J Zoo Wildl Med 30 145ndash150

3 Hurley K M W Miller M D Willard and H WBoothe 1993 Left aortic arch and right ligamentum ar-teriosum causing esophageal obstruction in a dog J AmVet Med Assoc 203 410ndash412

4 Jeffrey S C N Bataller R A Martin and M LMoon 1995 Postsurgical nutritional management ofmegaesophagus secondary to persistent right aortic archin a kitten Feline Pract 23 17ndash23

5 Mudoon M M S J Birchard and G W Ellison1997 Long term results of surgical corrections of persis-tent right aortic arch in dogs 25 cases (1980ndash1995) JAm Vet Med Assoc 210 1761ndash1763

6 Rochat M C and E S Settles 1993 Persistentright aortic arch in a cougar (Felis concolor) J ZooWildl Med 24 534ndash538

7 Shires P K and W Liu 1981 Persistent right aorticarch in dogs a long term follow-up after surgical correc-tion J Am Anim Hosp Assoc 17 773ndash776

8 Thornton I W B 1978 White tiger geneticsmdashfur-ther evidence J Zool 185 389ndash394

9 Wysong R L 1969 Embryology of persistent rightaortic arch Vet Med Sm Anim Clin March 1969 204ndash209

Received for publication 27 June 2000

ERRATA

Infectious and Parasitic Diseases and Contaminant-Related Problems of North American River Otters (Lontra cana-densis) A Review KEVIN R KIMBER and GEORGE V KOLLIAS JZWM v 31 (4)454ndash472

Page 466 1st paragraph final sentence should read lsquolsquoNumerous studies throughout North America have shownan association between high concentrations of contaminants and disease or population declines in L canaden-sis145862135169170 Studies showing causal links between exposure and disease in L canadensis are uncommonrsquorsquo107108

271KETZ ET ALmdashVASCULAR ANOMALY IN A TIGER

Figure 3 Right lateral and ventrodorsal radiographs of a white Bengal tiger (Panthera tigris) obtained duringnonselective angiography Mild aneurysmal dilation of the descending aorta (white arrows) present at the level ofcontrast material stoppage during the esophagram (A) The ventrodorsal radiograph with dextropositioning of the aorta(black arrowheads) An aberrant vessel is coursing toward the left forelimb consistent with the left subclavian artery(white arrows) (B)

272 JOURNAL OF ZOO AND WILDLIFE MEDICINE

ring anomaly was confirmed by radiography con-trast studies of the esophagus esophagoscopy fluo-roscopy and nonselective angiography The leftsubclavian artery probably originated from the leftseventh intersegmental artery rather than the leftfourth aortic arch because the aberrant vesselcoursed dorsal to the esophagus Therefore twocompressions could be observed a mild compres-sion from the aberrant left subclavian artery and asevere constriction due to the ligamentum arterios-um In this case ligature of the left subclavian ar-tery was not performed because of the lack of acomplete ring at the site and the risk of compromiseof the circulation to the left forelimb

Whether genetic or hemodynamic factors lead tothe development of vascular ring anomalies is un-known In dogs evidence of a hereditary basisleading to PRAA has been documented57 WhiteBengal tigers are significantly inbred8 Because agenetic cause for the development of the PRAA andthe left aberrant subclavian artery in this tiger can-not be eliminated we strongly recommendedagainst future breeding of this tiger

Acknowledgments We acknowledge Dr DonaldMayfield for referring the tiger Drs Julie Fisherand Susan Kraft for assistance in the diagnosticworkup and Drs Rose McMurphy and DavidHodgson for assistance with anesthesia

LITERATURE CITED

1 Fox P R 1988 Congenital feline heart disease InFox P R (ed) Canine and Feline Cardiology ChurchillLivingstone Inc New York New York Pp 404ndash408

2 Goldin J P and N E Lambrechts 1999 Doubleaortic arch and persistent left vena cava in a white lioncub (Panthera leo) J Zoo Wildl Med 30 145ndash150

3 Hurley K M W Miller M D Willard and H WBoothe 1993 Left aortic arch and right ligamentum ar-teriosum causing esophageal obstruction in a dog J AmVet Med Assoc 203 410ndash412

4 Jeffrey S C N Bataller R A Martin and M LMoon 1995 Postsurgical nutritional management ofmegaesophagus secondary to persistent right aortic archin a kitten Feline Pract 23 17ndash23

5 Mudoon M M S J Birchard and G W Ellison1997 Long term results of surgical corrections of persis-tent right aortic arch in dogs 25 cases (1980ndash1995) JAm Vet Med Assoc 210 1761ndash1763

6 Rochat M C and E S Settles 1993 Persistentright aortic arch in a cougar (Felis concolor) J ZooWildl Med 24 534ndash538

7 Shires P K and W Liu 1981 Persistent right aorticarch in dogs a long term follow-up after surgical correc-tion J Am Anim Hosp Assoc 17 773ndash776

8 Thornton I W B 1978 White tiger geneticsmdashfur-ther evidence J Zool 185 389ndash394

9 Wysong R L 1969 Embryology of persistent rightaortic arch Vet Med Sm Anim Clin March 1969 204ndash209

Received for publication 27 June 2000

ERRATA

Infectious and Parasitic Diseases and Contaminant-Related Problems of North American River Otters (Lontra cana-densis) A Review KEVIN R KIMBER and GEORGE V KOLLIAS JZWM v 31 (4)454ndash472

Page 466 1st paragraph final sentence should read lsquolsquoNumerous studies throughout North America have shownan association between high concentrations of contaminants and disease or population declines in L canaden-sis145862135169170 Studies showing causal links between exposure and disease in L canadensis are uncommonrsquorsquo107108

272 JOURNAL OF ZOO AND WILDLIFE MEDICINE

ring anomaly was confirmed by radiography con-trast studies of the esophagus esophagoscopy fluo-roscopy and nonselective angiography The leftsubclavian artery probably originated from the leftseventh intersegmental artery rather than the leftfourth aortic arch because the aberrant vesselcoursed dorsal to the esophagus Therefore twocompressions could be observed a mild compres-sion from the aberrant left subclavian artery and asevere constriction due to the ligamentum arterios-um In this case ligature of the left subclavian ar-tery was not performed because of the lack of acomplete ring at the site and the risk of compromiseof the circulation to the left forelimb

Whether genetic or hemodynamic factors lead tothe development of vascular ring anomalies is un-known In dogs evidence of a hereditary basisleading to PRAA has been documented57 WhiteBengal tigers are significantly inbred8 Because agenetic cause for the development of the PRAA andthe left aberrant subclavian artery in this tiger can-not be eliminated we strongly recommendedagainst future breeding of this tiger

Acknowledgments We acknowledge Dr DonaldMayfield for referring the tiger Drs Julie Fisherand Susan Kraft for assistance in the diagnosticworkup and Drs Rose McMurphy and DavidHodgson for assistance with anesthesia

LITERATURE CITED

1 Fox P R 1988 Congenital feline heart disease InFox P R (ed) Canine and Feline Cardiology ChurchillLivingstone Inc New York New York Pp 404ndash408

2 Goldin J P and N E Lambrechts 1999 Doubleaortic arch and persistent left vena cava in a white lioncub (Panthera leo) J Zoo Wildl Med 30 145ndash150

3 Hurley K M W Miller M D Willard and H WBoothe 1993 Left aortic arch and right ligamentum ar-teriosum causing esophageal obstruction in a dog J AmVet Med Assoc 203 410ndash412

4 Jeffrey S C N Bataller R A Martin and M LMoon 1995 Postsurgical nutritional management ofmegaesophagus secondary to persistent right aortic archin a kitten Feline Pract 23 17ndash23

5 Mudoon M M S J Birchard and G W Ellison1997 Long term results of surgical corrections of persis-tent right aortic arch in dogs 25 cases (1980ndash1995) JAm Vet Med Assoc 210 1761ndash1763

6 Rochat M C and E S Settles 1993 Persistentright aortic arch in a cougar (Felis concolor) J ZooWildl Med 24 534ndash538

7 Shires P K and W Liu 1981 Persistent right aorticarch in dogs a long term follow-up after surgical correc-tion J Am Anim Hosp Assoc 17 773ndash776

8 Thornton I W B 1978 White tiger geneticsmdashfur-ther evidence J Zool 185 389ndash394

9 Wysong R L 1969 Embryology of persistent rightaortic arch Vet Med Sm Anim Clin March 1969 204ndash209

Received for publication 27 June 2000

ERRATA

Infectious and Parasitic Diseases and Contaminant-Related Problems of North American River Otters (Lontra cana-densis) A Review KEVIN R KIMBER and GEORGE V KOLLIAS JZWM v 31 (4)454ndash472

Page 466 1st paragraph final sentence should read lsquolsquoNumerous studies throughout North America have shownan association between high concentrations of contaminants and disease or population declines in L canaden-sis145862135169170 Studies showing causal links between exposure and disease in L canadensis are uncommonrsquorsquo107108