Reliability of detecting fundus abnormalities associated with systemic hypertension in cats assessed by veterinarians with and without ophthalmology specialty training

Abstract

Objectives: Systemic hypertension (SHT) causes severe target organ damage (TOD) and blood pressure (BP) measurement should be routine in at-risk populations. Fundoscopy is a tool to corroborate acute clinical relevance of high BP results and to decide on immediate therapy. Not every cat with a high BP result can be examined by an ophthalmologist. The study objective was to determine the reliability of fundoscopy in cats with SHT performed by a veterinarian without ophthalmology specialty training.

Methods: Cats with suspicion of hypertensive TOD or belonging to an at-risk population for SHT with a first measurement of elevated BP >160 mmHg were enrolled. Indirect ophthalmoscopy was performed by a recent graduate veterinarian followed by a veterinary ophthalmologist. Confirmation of SHT was based on two additional sets of systolic BP measurements >160 mmHg by Doppler sphygmomanometry.

Results: Thirty-three cats were included. SHT was confirmed in 27 cats. SHT was detected on routine examinations in 12/27 cats; fundoscopic lesions were observed in 9/12 by the non-trained veterinarian and in 11/12 by an ophthalmologist. Nine of 27 cats were neurological patients; fundoscopic lesions were detected in 4/9 by the non-trained veterinarian and in 7/9 by an ophthalmologist. Six of 27 cats were presented for acute blindness; fundus lesions were detected in all six cats by the non-trained veterinarian and ophthalmologist. SHT was not confirmed and fundoscopic lesions were not detected by either examiner in 6/33 cats. Compared with a veterinary ophthalmologist, reliability of detecting fundus abnormalities by the non-trained veterinarian was 72% (13/18) for cats with, and 100% (6/6) for cats without, vision.

Conclusions and relevance: Fundus examination by a non-specialty trained veterinarian has reasonably high reliability for the detection of ocular TOD. Private practice veterinarians are encouraged to perform an initial fundic examination in suspected hypertensive cats.

Keywords: Blood pressure; Doppler sphygmomanometry; feline hypertensive oculopathy; situational hypertension; target organ damage.

Figure 1

Fundus of a 17.5-year-old cat with a systolic blood pressure of 260 mmHg. The presenting complaint was acute vestibular syndrome. Pathological findings include a nasoventral preretinal haemorrhage of approximately twice the optic nerve head diameter (*), punctate retinal haemorrhages in the temporal and dorsal midperipheral tapetum (arrowheads) and multifocal bullous retinal detachments (arrows). The generalised haziness of the nasal half of the fundus suggests the presence of either generalised retinal oedema or a large flat or mildly elevated retinal detachment

Figure 2

Fundus of a 17-year-old cat with a systolic blood pressure of 208 mmHg. The presenting complaint was diarrhoea. Pathological findings include multifocal bullous retinal detachments (arrows) and areas of focal retinal oedema (dashed arrows)

Figure 3

Fundus of a 14.5-year-old cat with a systolic blood pressure of 220 mmHg. The presenting complaint was impaired vision. Pathological findings visible on this image include large dorsal retinal detachments (arrows), punctate haemorrhages (arrowheads) and larger retinal or preretinal haemorrhages (*), as well as generalised retinal oedema. The last is indicated by the fact that the image seems well focused but there is a generalised haziness/loss of fine retinal detail compared with the crisp detail visible in Figure 2

Figure 4

Fundus of a 10.5-year-old cat with a systolic blood pressure of 190 mmHg. The presenting complaint was ataxia. Pathological findings include an area of tapetal hyporeflectivity (star), a mild tortuosity of blood vessels (dotted arrows) and mild diffuse retinal oedema of the nasal retina. The last is indicated by the fact that the image seems well focused but there is a generalised haziness/loss of fine retinal detail in the nasal half of the fundus (right-hand side of the image) compared with the crisp detail visible in Figure 2 and in the temporal half of the fundus (left-hand side of the image)