作者：Crina Frincu-Mallos, PhD
出處：WebMD醫學新聞
October 20, 2008（馬里蘭州巴爾的摩）－以彩色都卜勒非侵入性地評估內皮細胞功能失調，可以作為未來心血管疾病風險的預測因子與指標，特別是代謝症候群病患。
主要作者、印度阿里格爾Jawharlal Nehru醫學院病理部的Sufian Zaheer博士在壁報發表中表示，目前這項研究最令人震撼的發現是，我們在一個進階多重複迴歸模式中看到內皮細胞功能異常作為共變相的預測能力。
這項研究發現發表於美國臨床病理學會2008年年會中。
根據美國心臟醫學會表示，當腹部肥胖、動脈硬化性血脂異常、高血壓、胰島素抗性或是葡萄糖耐受性不佳、易產生栓塞的狀況（例如血中纖維蛋白酶原或胞漿素活化抑制劑-1濃度過高）、以及易發炎狀態（例如血中C反應蛋白濃度過高），如果這些狀況同時存在，他們將其稱為代謝症候群。
Zaheer博士指出，一般而言，內皮細胞功能失調以生長促進與生長抑制因子、促動脈硬化與抑制動脈硬化因子、血管收縮與擴張因子、促進凝血與抑制凝血因子之間的失衡來定義。
Zaheer博士表示，對發生代謝症候群高風險病患評估內皮細胞功能失調，可以預測心血管疾病發病率與死亡率。
臨床上，內皮細胞功能失調可以以侵入性的方式評估，如透過冠狀動脈造影，或是非侵入性方式評估，如超音波。
紐約康乃爾大學以及卡達Weill康乃爾醫學院病理學與檢驗醫學副教授Power Peterson醫師在一項與Medscape病理學的訪談中談到，這是一項評估一種非侵入性方法（例如臂動脈血流調控的血管擴張）是否可以正確作為內皮細胞功能失調特定指標的關連性研究，特別是作為代謝症候群的參考依據；Peterson醫師並未參與這項研究。
總共有45位代謝症候群與20位健康受試者參與這項研究；Zaheer醫師與其同事透過高解析度超音波影像評估所有受試者的臂動脈血管擴張反應。
這項研究中與內皮細胞功能失調有關的多變項，包括空腹血糖、收縮壓、高密度脂蛋白（LDL）、低密度脂蛋白（LDL）與年齡。
Zaheer醫師解釋，HDL是這個迴歸模式中最顯著的預測因子，代表了66.4%預測能力以及44.1%整體變異度；根據Zaheer醫師與其同事的摘要，僅有HDL與內皮細胞功能失調反向相關；所有其他的變項都直接與內皮細胞功能失調有關。
作者的結論是，脂蛋白濃度與內皮細胞功能失調的關聯確實存在，Peterson醫師評論，他們有很穩固的證據來支持這樣的說法；但是我將會問的問題是：如果HDLs與LDLs以及空腹血糖是內皮細胞功能失調絕佳的內皮細胞功能失調預測因子，為什麼我們要做血流調控的血管擴張檢驗？這真的是符合經濟效益的工具？以及我們需要這個工具嗎？
Zaheer醫師的壁報被選為今年年會AJCP住院醫師研究發表會的前10名。
這項研究並未接受商業贊助。Zaheer醫師與Peterson醫師表示沒有任何相關資金上的往來。
Endothelial Dysfunction in Metabolic Syndrome May Predict Cardiovascular Risk
By Crina Frincu-Mallos, PhD
Medscape Medical News
October 20, 2008 (Baltimore, Maryland) — The noninvasive evaluation of endothelial dysfunction using color Doppler serves as a predictor and marker for future cardiovascular risk, especially in patients with metabolic syndrome.
"The most striking finding in the present study was the predictability of our covariates on the outcome of endothelial dysfunction in a stepwise multiple regression model," lead author Sufian Zaheer, MD, from the department of pathology at Jawaharlal Nehru Medical College, in Aligarh, India, said in his poster presentation.
The study findings were reported here at the American Society for Clinical Pathology 2008 Annual Meeting.
According to the American Heart Association, when abdominal obesity, atherogenic dyslipidemia, hypertension, insulin resistance or glucose intolerance, a prothrombotic state (e.g., high fibrinogen or plasminogen activator inhibitor-1 in the blood), and a proinflammatory state (e.g., elevated C-reactive protein in the blood) coexist, they are referred to as metabolic syndrome.
Endothelial dysfunction is generally defined as the imbalance between growth-promoting and growth-inhibiting factors, proatherogenic and antiatherogenic factors, vasodilators and vasoconstrictors, and procoagulant and anticoagulant factors, explained Dr. Zaheer.
Evaluation of endothelial dysfunction in patients at risk of developing metabolic syndrome can predict cardiovascular morbidity and mortality, noted Dr. Zaheer.
Clinically, endothelial dysfunction can be estimated invasively, using coronary catheterization, or noninvasively, with ultrasound.
"This is a correlation study evaluating whether or not a noninvasive method [i.e., brachial artery flow-mediated dilation] is actually able to quantify a certain marker for endothelial dysfunction, specifically with reference to the metabolic syndrome," Powers Peterson, MD, an associate professor of pathology and laboratory medicine at Cornell University, in New York, New York, and Weill Cornell Medical College, in Qatar, told Medscape Pathology in an interview. Dr. Peterson was not involved in the study.
A total of 45 patients with metabolic syndrome and 20 healthy subjects participated in this study.
For all study participants, Dr. Zaheer and colleagues assessed the vasodilatory response in the brachial artery using high-resolution ultrasound images.
The multivariate correlates of endothelial dysfunction in this study were fasting blood sugar, systolic blood pressure, levels of high-density lipoprotein (HDL) and low-density lipoprotein (LDL), and age.
"HDL was the most significant of all the predictors in the regression model, accounting for 66.4% predictability and 44.1 % total variance," explained Dr. Zaheer. Only HDL was inversely associated with endothelial dysfunction; all other variables were directly related to endothelial dysfunction, according to the abstract by Dr. Zaheer and colleagues.
"The authors concluded that the correlation between lipid profiles and endothelial dysfunction does exist," commented Dr. Peterson, "and they have reasonably solid statistical evidence to support it. But the question I would ask is: If HDLs and LDLs and fasting blood sugars are excellent surrogate predictors of endothelial dysfunction, why are we doing flow-mediated dilation? Is this really a cost-effective tool, and do we really need it?"
Dr. Zaheer's poster was selected among the best 10 AJCP Resident Research Symposium presentations at this year's meeting.
The study did not receive commercial support. Neither Dr. Zaheer nor Dr. Peterson have disclosed any relevant financial relationships.
American Society for Clinical Pathology (ASCP) 2008 Annual Meeting: Poster 45. Presented October 17, 2008.
[ 本帖最後由 goodcat1111 於 2008-10-31 11:28 編輯 ] |
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