The paper describes the clinical, diagnostic and pathological features of oesophageal strictures that developed after various surgical procedures performed under general anaesthesia in five dogs and two cats. Consideration of possible predisposing causes suggests that the complication is due to gastro–oesophageal reflux during anaesthesia.

Summary:In the last 15 years, intense interest has focused on various interventional pharmacologic and mechanical forms of therapy for the treatment of atherosclerosis coronary artery disease. Many techniques and devices (dilating balloons, perfusion catheters, thermal probes and balloons, lasers, atherectomy devices, stents, intravascular ultrasound) have been used or are under study for future use. Many of these techniques and devices require an understanding of histologic and pathologic features of the coronary arteries and diseases which affect them. This article reviews selective areas of anatomy, histology, and pathology relevant to the use of various new interventional Part I of this review will focus on anatomic aspects of the epicardial coronary artery system, coronary arterial distribution, myocardial supply, and histologic features of the normal coronary artery. Key words: coronary artery, coronary ostium, high takeoff position Epicardial Coronary Artery SystemThe epicardial coronary artery system consists of the left and right coronary arteries, which normally arise from 0s-tia located in the left and right sinuses of Valsalva, respec- tively ( Fig. 1). In about 50% of humans a "third coronary artery" ("conus artery") arises from a separate ostium in the right sinus. Additional smaller ostia may be found in the right sinus, which give rise to multiple right ventricular branches (Fig. 2). Up to five separate coronary ostia have been described (Figs. 2+.3 The left main coronary artery ranges in length from 1-25 mm before bifurcating into the left anterior descending and left circumflex bran~hes.~ The left anterior descending coronary artery measures from 10-13 cm in length, whereas the usual nondominant left circumflex artery measures about 6-8 cm in length. The usual dominant right coronary artery (supplying posterior descending and/or atrioventricular nodal artery) is about 12-14 cm in length before giving rise to the posterior descending artery. The luminal diameters of the major coronary arteries in adults range as follows: left main, 2.0-5.5 mm (mean 4 mm); left anterior descending, 2.0-5.0 mm (mean 3.6 mm); left circumflex, 1.5-5.5 mm (mean 3.0 mm); and right, 1.5-5.5 mm (mean 3.2 mm)? Although the left anterior descending and left circumflex arteries generally taper in diameter as each extends from the left main bifurcation, the right coronary artery maintains a fairly constant diameter until just before the origin of its posterior descending branch. The subepicardial coronary arteries run on the surface of the heart embedded in various amounts of subepicardial fat. Portions of the epicardial coronary arteries may dip into the myocardium ("mural artery" or "tunneled artery") and be covered for a variable length (1 to several mm)5 by ventricular muscle ("myocardial bridge") ( Coronary OstiaThe left and right coronary ostia arise normally within the sinus of Valsalva or at the junction of the sinus and tub-

The clinical presentation, diagnosis and surgical treatment of four cats with nasopharyngeal polyps are described. In three cats the microscopic appearance of the polyps together with the finding of radiographic densities in the tympanic bullae point to the middle ear as the origin of these polyps. These are inflammatory lesions and it is suggested that they occur as the result of ascending infection from the nasopharynx. Experience has shown that, in spite of recurrence in some cases, simple traction rather than bulla osteotomy is the preferred method of treatment.

This report describes clinical, morphologic and histologic findings at necropsy late (range 1.6 to 24.1 months [average 8.2 months]) after clinically successful coronary balloon angioplasty in 20 patients with coronary angioplasty restenosis. Clinical evidence of restenosis occurred in 14 patients (70%), including 6 patients with sudden coronary death. Of the 20 patients, 14 (70%) had a cardiac cause of death and 6 (30%) had a noncardiac cause of death. Two major subgroups of histologic findings were observed: 1) intimal proliferation (60%), and 2) atherosclerotic plaque only (40%). Of the eight sites with atherosclerotic plaque only, six were eccentric lesions and two were concentric lesions. No morphologic evidence of previous angioplasty injury (cracks, breaks, tears) was observed in the eight patients with atherosclerotic plaque only. Proposed mechanisms for the development of intimal proliferation involve the reaction of smooth muscle cells and platelets, whereas elastic recoil of overstretched eccentric or concentric atherosclerotic lesions represents the most likely explanation for the findings in the latter subgroup. On the basis of these morphologic findings at angioplasty restenosis sites, specific treatment strategies for restenosis after coronary artery balloon angioplasty are proposed.