Surgical Correction of Esophageal Stenosis by Right Aortic Arch Persistence in Two Cats

Background: Vascular ring anomaly is considered a hereditary change. It occurs when the fourth right aortic arch persists instead of the fourth left aortic arch, forming a vascular ring that compress the esophagus causing esophageal dilatation cranial to the compression site. Diagnosis is based upon anamnesis, physical examination, clinical signs and complementary exams (radiograph, complete blood count and biochemical tests). The clinical treatment is inadequate, since the dilatation persists and tends to progress causing irreversible tissue injury. Surgical correction is indicated and consists of the arterial ligament resection and correction of the esophageal stenosis.Case: The objective of the current study is to report two case of persistence of right aortic arch in two cats referred to the Veterinary Hospital of the Federal University of Santa Maria. On physical examination the patients were alert, in good nutritional status, adequately hydrated and presented normal colored mucous membranes. Each animal underwent radiog­raphy and esophagogram with barium sulphate. The exam demonstrated partial esophageal dilation cranial to the cardiac silhouette, suggestive of vascular ring anomaly. An exploratory thoracotomy was performed in order to achieve the definitive diagnosis. The arterial ligament was resected and esophageal stenosis corrected. Anesthesia, surgery and the postoperative period undergo without any complications. Patients remained hospitalized in the first 24 h for observation and were dis­charged after this period. Ten days surgery they returned for revaluation and removal of the skin suture. Four months after the surgical correction the animals underwent a new radiography and esophagogram examination. Radiographic findings evidenced persistence of esophageal dilation and narrowing of the esophageal lumen. Patients were evaluated periodically up to 10 months after surgery, verifying excellent quality of life and remission of clinical signs.Discussion: Vascular ring anomalies affects both dogs and cats, occurring more commonly in purebred dogs than in mixed breed. The literature reports cases in young Siamese and Persian cats, although the absolute numbers are insufficient to make conclusions about the racial predisposition. This case report enrolled two cases of PRAA in adult mixed breed cats (one male and one female from the same litter). Surgical correction is the recommended treatment for PRAA, either con­ventional or minimally invasive techniques. To assist the dissection of the fibrous ring and correction of esophageal stenosis we utilized a 22 Fr Foley catheter, introduced through the oral cavity to the esophageal stenotic area. The inflation of the balloon on the constricted area allows visualization of residual fiber rings and facilitates its dissection and removal. The PRAA mortality is associated with late diagnosis and the coexistence of aspiration pneumonia. Therefore, surgery should be performed as soon as possible after the onset of clinical signs, in order to reduce damage to the esophageal muscles and nerves. It is estimated that 80% of cases survived the postoperative period. In both cases, no clinical signs were observed, and there was a reduction of the esophageal diameter compared with the previous dilation, as well as better esophageal transit. Ten months after surgery, the animals returned for revaluation, presenting adequate body development and good quality of life. As shown in this case report, surgical intervention allowed for the accurate diagnosis and correction of PRAA in cats, with remission of clinical signs and full recovery of the animal.Keywords: cat, regurgitation, megaesophagus, thoracotomy, anomaly