대한진단검사의학회지 : 제 25 권제 1 호 2005 Korean J Lab Med 2005; 25: 28-32 임상화학 혈액투석을받는만성신부전환자에서의심근 Troponin T 증가에대한고찰 박민정 이영경 송원근 허미나 이계숙 1 조현찬 이규만 한림대학교의과대학진단검사의학교실, 시립동부병원진단검사의학과 1 Investigation of Elevated Cardiac Troponin T in Chronic Renal Failure Patients Undergoing Hemodialysis Min Jeong Park, M.D., Young Kyung Lee, M.D., Wonkeun Song, M.D., Mina Hur, M.D., Kye Sook Lee, M.D. 1, Hyoun Chan Cho, M.D., and Kyu Man Lee, M.D. Department of Laboratory Medicine, College of Medicine, Hallym University; Department of Laboratory Medicine, Dongbu Municipal Hospital 1, Seoul, Korea Background : The aim of this study was to investigate the prevalence and clinical significance of abnormal values of cardiac markers, high sensitivity CRP (hscrp) and homocysteine occurring in hemodialysis patients without clinical evidence of acute coronary ischemia. Methods : We determined the concentrations of cardiac troponin T (ctnt), troponin I (ctni), creatine kinase MB (CK-MB), myoglobin, hscrp, homocysteine and other biochemical parameters in 35 patients with chronic renal failure (CRF) and 22 healthy controls. All CRF patients were followed for 3 years. Results : All of the measured parameters except cholesterol were significantly elevated in the patients, comparing with controls (P<0.01). The numbers with elevated values above cutoff levels in CK-MB, ctnt, ctni and hscrp did not show any significant differences between the two groups (P>0.05). A good association was present between ctnt and CK-MB, ctnt and myoglobin, myoglobin and creatinine, and BUN and creatinine. Inquiries about underlying diseases of CRF revealed that diabetes mellitus group showed significantly higher ctnt values than in hypertension group or inflammation group. ctnt was elevated above cutoff value in about 17% of patients, while ctni was in none of them. During one-year follow-up period, 6 patients (18.2%) died and 3 of them had initially elevated ctnt values. Four patients had cardiac events, but none of them had any increase in the values of the cardiac markers. The patients with increased ctnt values above cutoff value ( 0.1 ng/ ml) showed a significantly higher mortality rate than the patients with ctnt values below the cutoff value in 3-year follow-up (P<0.05). Conclusions : Mildly elevated cardiac markers, hscrp and homocysteine are common in CRF patients undergoing hemodialysis. It is recommended that ctni values be used for diagnosis of ischemic heart disease in CRF patients. The three-year follow-up outcome suggests that ctnt is a potential prognostic marker of mortality in CRF patients. (Korean J Lab Med 2005; 25: 28-32) Key Words : Chronic renal failure, Cardiac markers, hscrp, Homocysteine 접수 : 2004 년 5 월 12 일접수번호 : KJLM1754 수정본접수 : 2004 년 11 월 30 일교신저자 : 박민정우 150-950 서울시영등포구대림 1 동 948-1 한림대학교강남성심병원진단검사의학과전화 : 02-829-5258, Fax: 02-847-2403 E-mail: mjpark@hallym.or.kr 서론투석치료중인만성신부전환자들에서허혈성심질환은매우중요한사망원인의하나이다 [1]. 특히심근경색증은진단과동시에적절한치료가필요하므로신속하고정확한진단이필수적이다. 심 28
만성신부전에서심근 Troponin T 증가의의미 29 근손상의지표로사용되는검사중에서 creatine kinase MB (CK- MB), troponin T (ctnt) 와 I (ctni) 등은심근특이성이높아허혈성심질환의진단에유용하게사용되고있으나, 만성신부전환자들에서심근손상의증거없이 CK-MB와 ctnt가증가되어있다는보고들이있어왔다 [2, 3]. ctni의농도가급성허혈성심질환환자의예후추정에중요한위험인자라는것은잘알려져있으나, 만성신부전환자들에서 ctnt의증가가예후추정에서갖는의미는아직확실하지않다 [4, 5]. 또한만성신부전환자들은허혈성심근손상의위험이높지만, 그증상이전형적이지않고심근손상의표지자가지속적으로증가해있는경우실제심근손상여부를정확하게평가하기에어려움이있다. 만성신부전환자들에서각종심장표지자들과관상동맥질환의새로운위험인자들에관한국내의연구가매우적고, 특히예후와의관련성에대해서는아직일치된견해가없는상태이다. 그러므로본연구에서는최근 1년간심근손상의증거가없었던혈액투석중인만성신부전환자들을대상으로각종심장표지자및 high sensitivity CRP (hscrp) 와 homocysteine 등의관상동맥질환의위험인자를측정하여그양상을파악하고각지표간의연관성을분석하여만성신부전환자에서의허혈성심질환진단에대한기초자료로삼아향후진단을위한지침을마련하고자하였으며, 이후 3년간의경과를추적관찰함으로써만성신부전환자에서각종표지자의심근손상에대한진단적가치및예후와의관련성을규명하고자하였다. 대상및방법 1. 대상 2000년 8월에한림대학교성심병원에서혈액투석치료를받고있는만성신부전환자 38명중에서최근 1년간의병록지검토를통하여심전도이상이나흉통등의허혈성심질환을의심할만한임상증상이있었던 3명을제외한 35명 ( 남 14명, 여 21명 ; 평균연령, 58±12.3세 ) 과정상대조군 22명 ( 남 10명, 여 12명 ; 평균연령48±9.4세 ) 을대상으로하였으며, 이후 3년간의경과를추적하여허혈성심질환발생여부와임상경과를관찰하였다. 2. 방법대상환자들에서공복시의투석전혈액을혈청분리시험관에채혈하여원심분리한후혈청을분리하여 -70 냉동고에보관하였다가다음항목들을측정하였다. 심장표지자는 CK-MB, myogloin, ctni를 ACS:Centaur (Bayer Corporation, Ohio, USA) 로, ctnt는 Elecsys troponin T STAT (Roche Diagnostics GmbH, Mannheim, Germany) 로, hscrp는 Immage (Beckman Coulter, USA) 로, homocysteine은 IMx (Abbott Laboratories, Abbott Park, USA) 로측정하였으며, blood urea nitrogen (BUN), creatinine, glucose 및 cholesterol은 Hitachi 747 (Hitachi, Tokyo, Japan) 로측정하였다. 각종목의분별한계치는 CK-MB, 5 ng/ ml, myoglobin, 110 ng/ml, ctni, 0.5 ng/ml, ctnt, 0.1 ng/ ml 및 hscrp 3.0 mg/l로하였다. 정상대조군에서도공복시혈청으로환자군과동일하게측정하였다. 또한 3년간의추적기간동안병록지조사를통하여심근손상의임상증상과심전도변화및심장표지자의농도변화로허혈성심질환의발생여부를판단하였고임상경과를확인하였다. 3. 분석환자군과대조군에서의측정치의평균및중앙값의차이는 student t test와 Mann-Whitney U test로, ctnt, ctni와 CK-MB 의양성률에대한비교는 Fisher's exact test로각각분석하였으며, 환자군에서각측정물질상호간의연관성은 Pearson's correlation으로분석하였다. 또한만성신부전환자군을원인질환에따라분류하여각군간에측정치에서의유의한차이가있는가를분석하였으며, 추적관찰기간동안의사망률을비교하였다. 모든분석에서 P값 0.05 미만을통계적으로유의한것으로판단하였다. 결과 1. 각종심장표지자및생화학적지표의측정치비교 만성신부전환자군과대조군은 cholesterol 을제외한전종목에 서측정치의평균이나중앙값이유의한차이를나타내었다 (P<0.01, hscrp; P<0.05)(Table 1). 그러나 CK-MB, ctnt, ctni 와 hs- CRP에서분별한계치이상을나타낸양성률에대한비교에서는 ctni는두군모두에서음성이었고, CK-MB와 ctnt는환자군에서만각각 1명 (2.9%) 과 6명 (17.1%) 에서양성을보였으며, hs- Table 1. Comparisons of cardiac markers, hscrp, homocysteine and other biochemical parameters between CRF and control groups CRF (n=35) Control (n=22) P value CK-MB (ng/ml) 1.69±1.70 0.67±0.32 0.001 Troponin I (ng/ml) 0.08±0.05 0.02±0.03 <0.001 Myoglobin (ng/ml) 196.6±107.4 36.3±6.7 <0.001 Troponin T (ng/ml)* 0.025 (<0.01-0.343) <0.01 (<0.01) <0.001 Homocysteine ( mol/l) 23.2±6.3 9.6±2.4 <0.001 hscrp (mg/l)* 0.025 (<1.0-110) <1.0 (<1.0-6.58) <0.05 BUN (mg/dl) 52.4±12.3 12.1±2.1 <0.01 Creatinine (mg/dl) 7.7±3.0 0.9±0.1 <0.001 Glucose (mg/dl) 140.3±57.1 89.8±12.8 <0.001 Cholesterol (mg/dl) 172.0±47.2 189.2±25.6 NS Concentrations, mean±sd, *median (range); P <0.05, considered statistically significant. Abbreviations: CRF, chronic renal failure; NS, not significant.
30 박민정 이영경 송원근외 4 인 Table 2. Comparisons of positive rates of troponin T, troponin I, CK-MB and hscrp between CRF and control groups Group Total No. No.(%) of patients with positive results Troponin T Troponin I CK-MB hscrp CRF 35 6 (17.1) 0 (0) 1 (2.9) 10 (28.6) Control 22 0 (0) 0 (0) 0 (0) 2 (9.1) P value* NS NS NS NS *P <0.05, considered statistically significant. Abbreviation: NS, not significant. Table 3. Pearson s correlation coefficients (r) of cardiac markers, hscrp, homocysteine and other biochemical parameters in CRF patients BUN Cr Glu Chol CK-MB Myo ctni ctnt Hcy Cr.432* Glu.086 -.163 Chol -.298 -.440*.104 CK-MB.363 -.059.265*.016 Myo.279.482*.364 -.097.364 ctni.142.239 -.244.100.005.228 ctnt.069 -.065.222.080.738*.540*.257 Hcy.098.265 -.249 -.331.066.419.000.220 hscrp.105 -.074 -.146.174 -.034 -.084.273.100.084 Statistically significant, *P <0.01, P <0.05. Abbreviations: Cr, creatinine; Glu, glucose; Chol, cholesterol; CK-MB, creatine kinase MB; ctni, troponin I; ctnt, troponin T; Hcy, homocysteine. CRP는환자군에서 10명 (28%), 대조군에서 2명 (9%) 이양성을보였으나, 네항목모두에서환자군은대조군과통계적으로유의한차이를나타내지않았다 (P>0.05) 그러나환자군에서 ctnt와 ctni의양성률은유의한차이를나타내었다 (P<0.05)(Table 2). ctnt의농도가분별한계치이상인 6명에서 ctnt 의평균농도는 0.229 ng/ml (range, 0.114-0.343 ng/ml) 이었다. 2. 각측정물질농도상호간의연관성 (Table 3) 만성신부전환자군에서각측정물질의농도상호간에는 BUN 과 creatinine (r=0.432), myoglobin과 creatinine (r=0.482), CK- MB와 ctnt (r=0.738), myoglobin과 ctnt (r=0.540), CK- MB와 BUN (r=0.363), CK-MB와 myoglobin (r=-0.364) 및 creatinine과 cholesterol (r=-0.440) 이유의한연관성을가지는것으로나타났다 (P<0.05). 3. 만성신부전의원인질환별측정치비교 (Table 4) 대상환자군을만성신부전의원인질환에따라분류하여당뇨 (DM, 15명 ), 고혈압 (HT, 13명 ) 과염증 (I, 3명 ) 및기타 ( 신절제 1명, 다낭성신 1명, 원인미상 2명 ) 로나누고, 이중당뇨, 고혈압, 염증의세군을대상으로각군에서의측정치를비교하였다. 당뇨 Table 4. Comparisons of cardiac markers, hscrp, homocysteine and other biochemical parameters between underlying causes of CRF DM (n=15) HT (n=13) I (n=3) P value CK-MB (ng/ml) 2.44±2.24 1.16±0.89 0.51±0.34 NS Troponin I (ng/ml) 0.07±0.05 0.07±0.05 0.08±0.04 NS Myoglobin (ng/ml) 208.8±115.0 164.2±101.1134.9±57.4 NS Troponin T 0.11±0.12*, 0.02±0.03* 0.004±0.007 *P<0.05, (ng/ml)*, <0.01 Homocysteine 21.2±7.7 25.0±5.1 18.5±1.2 NS ( mol/l) hscrp (mg/l) 2.43±3.0 10.5±34.2 2.66±2.5 NS BUN (mg/dl) 52.7±12.6 50.5±11.9 49.2±18.7 NS Creatinine (mg/dl) 6.8±2.2 7.7±3.3 9.5±4.5 NS Glucose (mg/dl) 172.3±60.3 107.3±32.5 164.7±76.6 P<0.01 Cholesterol 191.7±55.2* 155.6±31.9* 158.0±45.5 *P<0.05 (mg/dl)* Concentrations, mean±sd; statistically significant, *P <0.05, P <0.01. Abbreviations: CRF, chronic renal failure; DM, diabetes mellitus; HT, hypertension; I, inflammation; NS, not significant. Table 5. Comparisons of mortality rates of CRF patients in 1-, 2- and 3-year follow-up periods according to ctnt values ctnt 1-year 2-year 3-year <0.1 ng/ml 10.7% (3/28) 19.2% (5/26) 28.0% (7/25) 0.1 ng/ml 50.0% (3/6) 60.0% (3/5) 80.0% (4/5) P value* NS NS P<0.05 *P <0.05, considered statistically significant. Abbreviation: NS, not significant. 군은고혈압군에비하여 glucose (P<0.01), cholesterol 및 ctnt (P<0.05) 가, 염증군에비해서는 ctnt (P<0.01) 가통계적으로유의하게증가되었다. 4. 추적관찰기간동안의임상경과 1년간의추적관찰기간동안 35명의만성신부전환자중 1명이추적에실패하였고, 6명 (17.6%) 이사망하였으며, 다른 4명 (11.8%) 에서허혈성심질환을의심할만한증상과심전도변화가있었으나 심장표지자농도의증가는없었다. 사망한 6명의직접사인은뇌간압박, 상부위장관출혈, 폐암, 패혈증등으로허혈성심질환과직접적인관련은없었으나, 이중 3명에서최초의 ctnt 농도가분별한계치이상이었다. 허혈성심질환의발생이의심된 4명에서최초의 CK-MB, ctnt, ctni 농도는모두분별한계치미만이었고, hscrp는 1명, myoglobin은 3명에서분별한계치이상이었다. 3년간의추적관찰기간동안총 5명에서추적에실패하였다. 환자군에서최초의 ctnt 농도가분별한계치미만이었던군와이상이었던 군의사망률을나누어조사한결과, 1 년사망률은각각 10.7% (3/ 28) 와 50% (3/6), 2년사망률은 19.2% (5/26) 와 60% (3/5) 및 3년사망률은 28% (7/25) 와 80% (4/5) 로 3년사망률에서만유의한차이를나타내었다 (P<0.05, Table 5).
만성신부전에서심근 Troponin T 증가의의미 31 고찰투석치료중인만성신부전환자들에서허혈성심질환은매우중요한사망원인의하나이며, 특히심근경색증은진단과동시에적절한치료가필요하므로신속하고정확한진단이필수적이다. 심근경색증의진단을위해서는 troponin과 CK-MB의농도를측정하여전형적인증감양상을보는것이중요하나 [6], 만성신부전환자에서는 CK-MB와 troponin T가심근손상의증거없이증가한경우가자주보고되고있어, 비전형적인흉통을호소하거나심전도소견이특징적이지않은경우에이들의측정이진단에혼란을줄수있다 [2, 3]. CK-MB는만성신부전환자의 3.8-50% 에서증가가보고되었으나본연구에서는한명에서만증가하여 2.9% 로기존의보고보다낮은수치를보여주었다. 보다심근특이적인지표인 troponin 중에서 troponin I는만성신부전환자에서도거의증가하지않으며 [7, 8] 이것은본연구의결과와도일치하여, ctni가골격근손상이나신부전시에심근손상을감별할수있는좋은지표임을확인할수있었다 [9]. 이에반해, ctnt는심근손상의증거없는신부전환자의 27-78% 에서증가가보고되었으며 [2, 10, 11], 본연구에서는이보다적은 17% 의환자에서 ctnt가증가하였다. ctnt의이러한비특이적인증가는신부전환자에서발생하는근병증과근육의재생과정에서 ctnt가발현되기때문이라고하나 [10], 골격근을생검하여분석한결과골격근에서 ctnt의 mrna와단백발현이없었으므로그증가는투석중에발생하는반복적인미세한심근세포의손상에기인한다고하였다 [12]. 그외에 ctnt 검사상의비특이적인반응이나골격근 ctnt와교차반응을일으킬가능성이제기되었으나 [8, 13] 정확한증가기전은규명되지않았다. 만성신부전환자군은관상동맥질환의독립적인위험인자인 hs- CRP와 homocysteine 농도가대조군보다높았다. Homocysteine 은만성신부전환자에서정상인의 2-3배증가를보이는데, 이러한고homocysteine혈증은소변으로의배설이감소하고요독증이 homocysteine의대사에관여하는효소를억제하기때문인것으로알려져있다 [14]. 만성신부전환자에서측정한각종지표들간의상호연관성에관한분석을시행한결과, BUN과 creatinine 및 CK-MB, myoglobin 과 creatinine, ctnt와 CK-MB 및 myoglobin이양 (positive) 의연관성을, creatinine과 cholesterol은음 (negative) 의연관성을가지는것으로나타났다. 이것은 ctnt와 creatinine 및 myoglobin 이상관관계를보인다는 Frankel 등의결과와는유사하나 [11], ctnt 농도가 CK, CK-MB, urea 및 creatinine의농도가상관관계가없다는다른주장들과는차이가있었다 [15, 16]. Collison 등 [13] 은 ctnt가 urea와 creatinine과는연관되어있으나 CK와 CK-MB와는연관되지않았다고하여 ctnt의증가와신기능저하와관계되어있을가능성을시사하였다. 만성신부전의원인질환별분석에서는 ctnt의농도가당뇨군에서고혈압군및염증군보다유의하게높은값을보였으며, 원인질 환이당뇨인환자중에서는 40% 가 ctnt의증가를나타내었다. 윤등 [17] 도신부전환자에서당뇨군과비당뇨군을비교하여 ctnt 의양성률에유의한차이가있으며당뇨군의 52.4% 에서양성을보인다고하였다. Li 등 [16] 도원인질환이당뇨인신부전환자의 44% 에서 ctnt가증가하였으나, 대조군으로설정한당뇨환자들에서는 ctnt가증가하지않아당뇨자체에의한상승가능성을배제할수있었다. 1년간의추적관찰결과추적이가능했던 34명중 6명이사망하여약 18% 의사망률을나타내었고, 사망한 6명의직접사인은뇌간압박, 상부위장관출혈, 폐암, 패혈증등으로허혈성심질환과직접적인관련은없었다. 4명의환자에서같은기간동안에허혈성심질환발생이의심되었으나추적기간동안심장표지자의농도증가는없었다. 이들의최초의 CK-MB, ctnt, ctni 농도는모두분별한계치미만이었고, 한명에서만 hscrp가 5.71 mg/l로분별한계치를넘었으며, homocysteine의증가양상도허혈성심질환의발생이나사망률에있어서차이를보이지않았다. 최초의 ctnt 농도가분별한계치 (0.1 ng/ml) 이상이었던군과미만이었던군을나누어분석한결과, 1년사망률에서는유의한차이를보이지않았으나 3년사망률에서는 ctnt 농도가높은군이유의하게높은사망률을나타내었다. 이러한결과는만성신부전환자들에서 ctnt 증가가심질환발생을예측할수있다는기존의보고들 [18, 19] 과는부합하지않았으나, 34개월동안 244명의환자를추적한결과 ctnt 증가가비관상동맥질환에의한사망률에서유의한차이를나타냈다는 Ooi 등 [20] 의결과와일치하여, ctnt 농도가만성신부전환자에서사망률에대한예후적지표로서의가능성을시사하였다. 결론적으로, 혈액투석중인만성신부전환자에서각종심장표지자및 hscrp, homocysteine의농도는대조군과유의한차이를나타내므로결과해석시주의를요하고, ctnt의경우약 17% 의환자에서양성을나타내므로심근질환진단시에는보다심근특이성이높은 ctni를이용하는것이바람직하다하겠다. 또한, 3년간의추적관찰을통해 ctnt의증가가만성신부전환자에서사망률에대한예후적지표로서의가능성을제시할수있었다. 그러나본연구의대상환자수가많지않았던점을고려할때, 만성신부전환자에서허혈성심질환의발생이나사망률의예후적지표로서 ctnt 의역할에대해서좀더보완적인연구가필요한것으로생각된다. 요약배경 : 최근 1년간심근손상의증거가없었던혈액투석중인만성신부전환자를대상으로하여각종심장표지자의농도를측정하고 high sensitivity CRP (hscrp) 와 homocysteine과같은다른관상동맥질환의위험인자와의연관성을분석하여만성신부전환자에서심근손상에대한진단적가치및예후와의관련성을확인하고자하였다.
32 박민정 이영경 송원근외 4 인 방법 : 혈액투석중인만성신부전환자 35명 ( 남 14명, 여 21 명 ; 평균연령, 58±12.3세 ) 과정상대조군 22명 ( 남 10명, 여 12 명 ; 평균연령 48±9.4세 ) 을대상으로하여투석전혈청으로 CK- MB, myoglobin, troponin I (ctni), troponin T (ctnt), hs- CRP, homocysteine 및여러생화학적지표들을측정하였고, 만성신부전환자들에대한 3년추적조사를시행하였다. 결과 : 환자군과대조군에서 cholesterol을제외한전종목의측정치는유의한차이를나타내었다 (P<0.01, hscrp; P<0.05). 그러나두군간의CK-MB, ctnt, ctni 및hsCRP에대한양성률비교에서는모두유의한차이를나타내지않았다 (P>0.05). 각측정물질상호간에는 ctnt와 CK-MB (r=0.738), ctnt와 myoglobin (r=0.540), myoglobin과 creatinine (r=0.482) 및 BUN 과 creatinine (r=0.432) 등이유의한연관성을보여주었다. 환자군을원인질환별로분류하여비교한결과, 당뇨군은고혈압군과염증군에비해 ctnt 농도에서유의하게높은값을나타내었다. ctnt는심근손상의증거가없는만성신부전환자의약 17% 에서분별한계치이상의값을보였으나, ctni는모두음성이었다. 1년간의추적관찰기간동안 6명 (18.2%) 이사망하였으며, 그중에서 3명은최초의 ctnt 농도가증가된환자였다. 다른 4명의환자 (12.1%) 에서허혈성심질환을의심할만한증상과심전도변화가있었으나심장표지자의증가는없었다. 환자군에대한 3년간의추적관찰기간동안 ctnt가분별한계치보다증가한군은증가하지않은군보다유의하게높은사망률을나타내었다. 결론 : 혈액투석중인만성신부전환자군에서각종심장표지자, hscrp 및 homocysteine의농도는대조군보다유의하게증가되어있었으며, 만성신부전환자의심근질환진단시에는 ctnt보다심근특이적인 ctni를이용하는것이바람직하다고생각된다. 한편, 3년간의추적관찰결과, ctnt 농도는혈액투석환자에서사망률과연관이있으므로예후적지표로서의가능성을제시할수있을것으로사료되었다. 참고문헌 1. Parfrey PS. Cardiac and cerebrovascular disease in chronic uremia. Am J Kidney Dis 1993; 21: 77-80. 2. Hafner G, Thome-Kromer B, Schaube J, Kupferwasser I, Ehrenthal W, Cummins P, et al. Cardiac troponins in serum in chronic renal failure. Clin Chem 1994; 40: 1790-1. 3. McLaurin MD, Apple FS, Voss EM, Herzog CA, Sharkey SW. Cardiac troponin I, cardiac troponin T, and creatine kinase MB in dialysis patients without ischemic heart disease: evidence of cardiac troponin T expression in skeletal muscle. Clin Chem 1997; 43: 976-82. 4. Ohman EM, Armstrong PW, Christenson RH, Granger CB, Katus HA, Hamm CW, et al. Cardiac troponin T levels for risk stratification in acute myocardial ischemia GUSTO IIA Investigators. N Eng J Med 1996; 335: 1333-41. 5. Ooi DS, Veinot JP, Wells GA, House AA. Increased mortality in hemodialyzed patients with elevated serum troponin T: a one-year outcome study. Clin Biochem 1999; 32: 647-52. 6. Keffer JH. The cardiac profile and proposed practice guideline for acute ischemic heart disease. Am J Clin Pathol 1997; 107: 398-409. 7. Musso P, Cox I, Vidano E, Zambon D, Panteghini M. Cardiac troponin elevations in chronic renal failure: prevalence and clinical significance. Clin Biochem 1999; 32: 125-30. 8. Bhayana V, Gougoulias T, Cohoe S, Henderson AR. Discordance between results for serum troponin T and troponin I in renal disease. Clin Chem 1995; 41: 312-7. 9. Trinquier S, Flecheux O, Bullenger M, Castex F. Highly specific immunoassay for cardiac troponin I assessed in noninfarct patients with chronic renal failure or severe polytrauma. Clin Chem 1995; 41: 1675-6. 10. Bodor GS, Survant L, Voss EM, Smith S, Porterfield D, Apple FS. Cardiac troponin T composition in normal and regenerating human skeletal muscle. Clin Chem 1997; 43: 476-84. 11. Frankel WL, Herold DA, Ziegler TW, Fitzgerald RL. Cardiac troponin T is elevated in asymptomatic patients with chronic renal failure. Am J Clin Pathol 1996; 106: 118-23. 12. Haller C, Zehelein J, Remppis A, Muller-Bardorff M, Katus HA. Cardiac troponin T in patients with end-stage renal disease: absence of expression in truncal skeletal muscle. Clin Chem 1998; 44: 930-8. 13. Collison PO, Stubbs PJ, Rosalki SB. Cardiac troponin T in renal disease. Clin Chem 1995; 41: 1671-3. 14. Bostom AG and Lathrop L. Hyperhomocysteinemia in end-stage renal disease: prevalence, etiology, and potential relationship to arteriosclerotic outcomes. Kidney Int 1997; 52: 10-20. 15. Collison PO, Hadcocks L, Foo Y, Rosalki SB, Stubbs PJ, Morgan SH, et al. Cardiac troponins in patients with renal dysfunction. Ann Clin Biochem 1998; 35: 380-6. 16. Li D, Keffer J, Corry K, Vazquez M, Jialal I. Nonspecific elevation of troponin T levels in patients with chronic renal failure. Clin Biochem 1995; 28: 474-7. 17. 윤정이, 이형철, 이준상, 박규용, 박대균, 구자룡등. 만성신부전환자에서심근 troponin I와 T 및 CK-MB의진단적의의. 대한내과학회지 2000; 58: 204-12. 18. Ishigami M and Yamaguchi S. Usefulness of serum tropoin-t (TnT) for prediction of cardiac death in hemodialysis (HD) patients. J Am Soc Nephrol 1994; 5: 455. 19. Wayand D, Baum H, Schatzle G, Scharf J, Neumeier D. Cardiac troponin T and I in end-stage renal failure. Clin Chem 2000; 46: 1345-50. 20. Ooi DS, Zimmerman D, Graham J, Wells GA. Cardiac troponin T predicts long-term outcomes in hemodialysis patients. Clin Chem 2001; 47: 412-7.