以超音波評估腎上腺功能亢進犬隻心臟及腎臟功能

Abstract

腎上腺功能亢進為中老年犬隻常見的內分泌疾病，長期暴露於高濃度的醣皮質醇會導致許多併發症，包括高血壓，左心室壁肥厚，心肌纖維化，絲球體硬化及血管阻力提高。除了結構改變，腎上腺功能亢進同時也會影響心臟及腎臟的功能，造成心臟舒張不良，尿液濃縮能力下降及蛋白尿比例提升。此論文包含兩個部份：（1）以腹腔超音波評估腎上腺功能亢進犬隻腎臟間動脈及後大動脈血管阻力改變，與蛋白尿與微蛋白尿的發生率（2）以新式的二維斑點追蹤超音波技術評估腎上腺功能亢進犬隻心肌運動性的改變。整體而言，腎上腺功能亢進犬隻顯著出現高血壓、心肌增厚、腎臟血管阻力增加與增加蛋白尿的發生率。此外本研究中，尿蛋白與腎臟阻抗係數成正相關，顯示尿蛋白的增加與腎臟血管阻力增加有關。在心臟評估方面，儘管傳統超音波用來計算心臟收縮功能的數值在所有犬隻都是正常且沒有差異的，但心肌厚的犬隻在斑點追蹤超音波結果顯示較正常犬來的低，其中又以腎上腺型腎上腺功能亢進的犬隻最為顯著。顯示心肌厚會同時影響舒張其收縮功能，而新式的二維斑點追蹤超音波可做為一敏感性較高的診斷工具。

Hyperadrenocorticism (HAC) is a common endocrine disorder in middle-aged and older dogs. Long-term exposure to high levels of glucocorticoids causes several complications, such as hypertension, left ventricular hypertrophy, myocardial fibrosis, glomerulosclerosis and elevated renal resistance. Meanwhile, HAC also contributed both cardiac and renal dysfunction. Left ventricular myocardial function was investigated using two-dimensional speckle tracking echocardiography (2D-STE). Resistive index (RI) and pulsatility index (PI) of the renal artery and aorta, as well as the presence of microalbuminuria were also evaluated. In the present study, the prevalence of hypertension, hypertrophic cardiomyopathy (HCM), renal vascular resistance and albuminuria were significantly increased in dogs with HAC compared with age-matched non-HAC group. In dogs with HCM, dogs with adrenal-dependent hyperadrenocorticism had significantly decreased longitudinal systolic and diastolic function despite systolic performance of left ventricular were normal when evaluated using parameters derived from the conventional echocardiography. The presence of albuminuria was positive associated with increased renal RI, suggesting that albuminuria might be associated with increased vascular resistance within the kidneys.