Echocardiographic and Radiographic Changes Associated with Systemic Hypertension in Cats

Abstract

The purpose of this study was to assess the effects of systemic hypertension (SHT) on echocardiographic and radiographic cardiovascular variables in affected cats compared with healthy geriatric cats. Secondary objectives were to determine whether there were any relationships between these findings and age or systolic blood pressure (SBP). Fifteen healthy cats (Ͼ8 years of age with normal SBP) and 15 hypertensive cats (SBP Ͼ 180 mm Hg) were studied. Each cat was evaluated for standard echocardiographic parameters and 4 different aortic root dimensions. Seventeen variables were measured from right lateral and dorsoventral radiographic views. Left ventrical wall thickness was greater in the SHT group (5.1 Ϯ 0.9 mm) than in the healthy cats (4.2 Ϯ 0.5 mm). Left ventricular hypertrophy in the SHT cats often was not severe, and mean measures were considered normal. Some cats had asymmetrical septal hypertrophy (ASH) in the basilar portion of the septum as determined from the 2-dimensional view of the left ventricular outflow tract. ASH was greater in cats with SHT. Comparisons of the proximal ascending aorta indicated the presence of dilatation in the SHT cats, and comparison of the ascending aorta to the aortic annulus was helpful in differentiating between the 2 groups. The distal aortic root measurements and ratios evaluated by echocardiography were significantly different between the 2 groups of cats (P ϭ .0001) and were significantly correlated with SBP (P ϭ .0001) but not age (P Ͼ .3).Key words: Aortic dilation; Aortic root; Asymmetric septal hypertrophy; Ventricular hypertrophy. Systemic hypertension (SHT) in cats has been most commonly associated with renal insufficiency and hyperthyroidism, but there have been sporadic reports of other possible causes.1-5 Manifestations of systemic hypertension may include acute blindness (hemorrhagic retinopathy), circling, ataxia or disorientation (cerebral hemorrhage), left ventricular hypertrophy (LVH), and possibly deterioration of renal function. [6][7][8][9] The serious nature of these consequences in cats with SHT makes detection and early intervention desirable.In humans, certain echocardiographic changes may be associated with SHT, including increased left ventricular mass index, concentric hypertrophy, left atrial enlargement, and asymmetric septal hypertrophy (ASH). In studies of humans with SHT, the prevalence of LVH is between 26% and 61%.10-12 Thus, LVH may not be a reliable indicator of SHT in some human patients. SHT also has been associated with aortic root enlargement or dilatation, which may be found primarily in the distal portions of the aortic root. Pullman, WA 99164-7060; e-mail: olnelson@vetmed.wsu.edu. Submitted May 9, 2001; Revised October 1, 2001; Accepted December 28, 2001 SHT and hemorrhagic retinopathy found a high frequency of cardiac enlargement visible on radiographs or echocardiograms or at necropsy. 2 In another study of cats in which LVH was diagnosed by echocardiography, approximately 47% of cats with LVH had SHT. 15 Other investigator...

Survival in cats with primary and secondary cardiomyopathies

“…[21][22][23][24] The present study is the first to present data from a feline referral population in Italy. HCM is the most common CM diagnosed at our institution (53% of the population included), followed by secondary CM (32% of the population included) and RCM (15%).…”

Cardiac Manifestations of Systemic Diseases

“…As in humans [14][15][16], left myocardial hypertrophy is the most frequent result of feline SHT [8][9][10][11][12]. The echocardiographic study conducted by Snyder et al, performed in 2001 on 19 hypertensive cats [8], demonstrated for the first time that these cats had significantly thicker septal and left ventricular free walls than normal cats.…”

“…The A3 and A4 diameters along with the A4/A1 and A3/A1 ratios were found to be significantly higher in hypertensive cats compared to a healthy feline control group. They were also positively correlated with the systolic arterial pressure value [9]. • Rarely, the aortic dilation secondary to SHT may lead to functional aortic regurgitation due to valvular annulus dilation (Figure 16-6).…”

“…It is much less frequent in the dog. Functional and morphologic cardiovascular changes secondary to SHT observed by conventional echo Doppler and tissue Doppler have been thoroughly described in the feline species [6][7][8][9][10][11][12]. Fewer data are available for the canine species [13].…”

“…• Dilation of the ascending aorta is a frequent modification associated with feline SHT (Figure 16-5). Nelson et al [9] evaluated the aortic diameter of 15 hypertensive cats in four different areas (using a right parasternal long axis view): the aortic annulus, the sinuses of Valsalva, the tubular junction, and the proximal ascending aorta (diameters corresponding to A1, A2, A3, and A4; see Figure 16-5). The A3 and A4 diameters along with the A4/A1 and A3/A1 ratios were found to be significantly higher in hypertensive cats compared to a healthy feline control group.…”