가정의학회지 2007;28:690-697 J Korean Acad Fam Med 원저 노인에서좌심실비대진단을위한심흉곽비 (Cardio-thoracic Ratio) 울산대학교의과대학강릉아산병원가정의학교실, * 순환기내과학교실 김성훈ㆍ신윤정ㆍ강희숙ㆍ윤혜경ㆍ오미경 ㆍ정상식 * 연구배경 : 좌심실비대는사망률및부정맥, 허혈성심장질환, 뇌졸중, 급사등과밀접한관계가있으며좌심실비대가호전됨에따라예후가좋아지는것으로알려져있다. 따라서일차진료에서좌심실비대를쉽고정확하게진단하는것이매우중요하다. 이에저자등은나이가듦에따라체형이달라진노인들을대상으로좌심실비대의기준으로가장적절한심흉곽비를구하고민감도및특이도를포함한진단율에미치는인자를알아보고자하였다. 방법 : 1997 년 3 월부터 2003 년 8 월까지일개종합병원종합건진센터에서방문하여심장초음파검사를받았던 60 세이상노인에서심장질환이없는사람 231 명을대상으로하였다. 좌심실질량은심장초음파검사를통해측정하였으며, Deveruex 의방법으로좌심실질량을키 (m) 의 2.7 배로나눈다음, 그값 ( 좌심실질량지수 ) 이남자 49.1 g/m 2.7 이상, 여자 46.7 g/m 2.7 이상을좌심실비대의기준으로삼았다. 심흉곽비는단순흉부후전위 (chest PA) 촬영에서심장의최대횡내경을흉곽의최대횡내경으로나누어값으로구하였다. 결과 : 심흉곽비를 0.45, 0.5, 0.55 를기준으로살펴보았으며진단일치율은남자는 0.5, 여자는 0.45 가가장높았으나민감도와특이도, 양성예측도를고려하여보았을때남녀모두 0.5 를기준으로삼는것이가장좋았다. 단순흉부후전위촬영으로좌심실비대를진단할때심흉곽비를 0.5 로기준으로하면여자는위양성률이높았고, 키가클수록위음성률이높았으며, 체질량지수 (BMI) 가증가할수록위음성률이높았다. 또한흡연을하였던경우는비흡연군에비해위음성률이높았고혈색소가높을수록위음성률이높았다. 결론 : 노인에서심흉곽비로좌심실비대를진단할때는기존의기준치와같게 0.5 으로정하는것이적절하였다. 또한성별및체형, 비만도, 흡연유무, 혈색소의정도를고려하여판단하여야할것으로생각한다. 중심단어 : 좌심실비대, 심흉곽비, 노인, 심초음파, 민감도, 특이도 서 좌심실비대는비정상적인심부하에대한심근의반응형태로서부정맥, 허혈성심장질환, 심부전, 뇌졸중, 돌연사등과밀접한관계가있으며좌심실비대가호전됨에따라예후가좋아지는것으로알려져있다. 1-7) 최근노인인구가증가하고생활양식의변화로인해비만인구가증가하면서고혈압이있는사람에게뿐만아니라고혈압이없는사람에게도나타나는경우가늘어나고있다. 8,9) 따라서일차의료에서좌심실비대를쉽고정확하게진단하는것이매우중요하다고볼수있다. 현재좌심실비대를진단하는방법으로는단순흉부방사선검사, 심전도검사, 심장초음파검사, 좌심실조 론 접수일 : 2006 년 8 월 29 일, 승인일 : 2007 년 8 월 16 일 교신저자 : 오미경 Tel: 033-610-3325, Fax: 033-641-8066 E-mail: omk@gnah.co.kr 영술, 자기공명영상등이있으며, 이중심장초음파검사가비교적정확한검사로알려져있다. 10-12) 하지만, 이방법은일차의료에서쉽게이용하기어렵고비용이많이들어보편화하기에는어려움이있다. 또한, 심전도검사는일차의료에서비교적쉽게시행할수있으나심전도검사만으로는좌심실비대의진단에있어서특이도는높으나민감도가낮은단점이있다. 13) 단순흉부방사선검사는일차의료에서쉽게시행할수있는검사로서심흉곽비 (cardio-thoracic ratio, CT ratio) 를측정하여좌심실비대진단에도움을주고있다. 14) 한편노화가진행됨에따라혈압, 특히수축기혈압은성인에비해 20 30% 증가하고형태학적으로는심근세포의숫자가감소하나심근개개세포의비대가관찰되는등, 심혈관계의구조적, 형태학적, 기능적변화가발생하며 15,16), 단순흉부방사선사진상심흉곽비가증가하여심비대로보이게된다. 17) 하지만, 심부전증이없는노인에있어서심흉곽비의증가가좌심실비대를얼마나대변하는지에대해서는아직충분한연구가되어있지않고심흉곽비도인종에따라서차이가있는것으로보고된바있기때문 690 가정의학회지
김성훈외 : 노인에서좌심실비대진단을위한심흉곽비 (Cardio-thoracic Ratio) 에 18), 기존의좌심실비대의심흉곽비기준을우리나라노인들에게그대로적용시키는것이적합하다고보기어렵다. 이에저자들은나이가듦에따라체형이달라진우리나라노인들을대상으로좌심실비대의기준으로가장적절한심흉곽비를구하고예민도및특이도를포함한진단률에미치는인자를분석하여일차의료에서노인들의좌심실비대의진단에도움을주고자연구를수행하였다. 1. 연구대상 방 1997 년 3 월부터 2003 년 8 월까지영동지역의일개종합병원종합건진센터를방문하여심장정밀검진 ( 심장초음파검사 ) 을받았던 60 세이상노인중에서심장판막질환, 관상동맥질환, 심근질환이없고심전도에서완전각차단 (complete bundle branch block), 심실내전도장애및조기흥분증후군이없는남자 103 명, 여자 128 명의총 231 명을대상으로하였다. 법 2. 연구변수의정의와측정 심장초음파검사는 Agilent 사의 SONOS 5500 과 Hewlett packard 사의 SONOS 2000 으로 2.25 MHz 탐촉자를사용하여좌측흉골연에서이면성심초음파의유도하에유두근부위에서 M 형심초음파도를기록하여좌심실확장기말내경 (left ventricular internal diameter at diastole, LVIDd), 심실중격두께 (interventricular septal thickness at diastole, LVPWd) 를측정하였고 19), 좌심실질량 (left ventricular mass) 은아래와같이 Devereux 등 20) 이수정한방법에의해산출하였고, 이를키 (m) 의 2.7 제곱로나누어좌심실질량지수값 (LV mass index) 을구한다음, 그값 ( 좌심실질량지수 ) 이남자 49.1g/m 2.7 이상, 여자 46.7g/m 2.7 이상일때를좌심실비대의기준으로삼았다. 21) 질량지수 (body mass index, BMI) 는자동신체계측기로얻은몸무게 (kg) 를키 (m) 의제곱으로나누어구한값으로하였으며혈압은서로다른날 2 번씩측정하여평균을구하여수축기혈압이 140 mmhg 이상이거나확장기혈압이 90 mmhg 이상인경우를고혈압으로정의하였고, 과거에진단을받은경우도포함하였다. 9 시간이상금식후혈청요산, 단백질, 알부민, AST (aspatate aminotransminase), ALT (alanin aminotransminase), rgt (r-glutamate transferase), 총빌리루빈, 혈당, 총콜레스테롤, 중성지방, 고밀도지단백콜레스테롤을자동분석기 (Hitachi 747 automatic analysis, Hitachi 사 ) 로측정하였다. 당뇨병의기준은 8 시간공복후혈당이 126 mg/dl 이상인경우로하였고과거에진단받은경우를포함하였다. 운동여부는주당 3 회이상의운동을하는경우로정의하였고검진당시에흡연을하고있는사람을과거흡연유무에상관없이현재흡연자로정의하였으며, 고혈압, 당뇨병, 흡연, 음주, 운동의병력은자기기입식설문지를이용하였다. 3. 분석방법 대상의일반적특성을남녀별로나누어각각의특성에대한평균과표준편차를조사하여비교하였고, 심초음파로진단된좌심실비대에대해임의로지정한심흉곽비 (0.45, 0.5, 0.55) 에따른민감도와특이도, 진단일치율 Left ventricular mass (g)=0.8 1.04 [(LVIDd+LVPWTd+ IVSTd) 3 (LVIDd) 3 ]+0.6 (g) LV mass index (g/m 2.7 )=left ventricular mass height 2.7 심흉곽비는단순흉부후전위 (chest PA) 촬영에서심장의최대횡내경을흉곽의최대횡내경으로나누어값으로구하였으며 ( 그림 1) 심흉곽비를 0.05 단위로나누어서 0.45, 0.5, 0.55 각각세가지의기준으로이에따른민감도, 특이도, 양성예측도, 음성예측도를측정하였다. 신체계측중키, 체중은자동측정기를이용하였고, 체 Figure 1. Definition of the measurements. Cardio-thoracic ratio (CTR)=(MR+ML)/TD. MR is length from mid-line of chest to maximal right cardiac border, ML is length from mid-line of chest to maximal left cardiac border. TD is the longest diameter of inner margin thoracic wall. Vol. 28, No. 9 691
Sung Hoon Kim, et al: Cardio-thoracic Ratio (CTR) for Detection of Left Ventricular Hypertrophy (LVH) in Elderly People Table 1. Baseline characteristics of study subjects. Sex (n=231) P value Male (n=103) Female (n=128) Height (cm) 165.9±5.6 152.0±3.5 <0.001 Weight (kg) 65.4±10.3 59.7±8.2 <0.001 BMI (kg/m 2 ) 23.7±2.9 25.6±2.8 0.035 Waist/hip ratio 0.91±0.05 0.90±0.06 0.446 Systolic BP (mmhg) 136.7±20.7 144.0±19.9 0.006 Diastolic BP (mmhg) 85.2±11.8 87.6±10.1 0.093 Hypertension ( 140/90 mmhg, %) 72 (69.9) 100 (78.1) 0.154* Total cholesterol (mg/dl) 183.4±37.7 204.4±42.4 <0.001 Triglyceride (mg/dl) 127.8±75.7 136.0±61.5 0.366 HDL-cholesterole (mg/dl) 46.8±12.2 50.6±12.8 0.024 LDL-cholesterole (mg/dl) 111.1±35.8 126.6±38.6 0.002 Hemoglobin (g/dl) 14.7±1.4 12.9±1.1 <0.001 DM (%) 11 (10.7) 23 (18.0) 0.120* LV mass index 49.1±10.8 56.1±15.9 <0.001 CT ratio (CTR) 0.47±0.05 0.51±0.04 <0.001 LVH (%) by echocardiography 54 (52.4) 90 (70.3) 0.005* Regular exercise ( 3 times/week) (%) 21 (20.4) 13 (10.2) 0.035* Smoking Non-smoker (%) 26 (25.2) 121 (94.5) Current smoker (%) 39 (37.9) 4 (3.1) <0.001* Ex-smoker (%) 38 (36.9) 3 (2.3) *P value by χ 2 square, P value by student t-test, BMI: body mass index, BP: blood pressure, HDL: high-density lipoprotein, LDL: low-density lipoprotein, DM: diabetes mellitus, LV: left ventricle, CTR: cardio-thoracic ratio, LVH: left ventricular hypertrophy. 을구하여남녀별로비교하였다. 그리고일반적특성에따른좌심실비대의위양성과진음성, 위음성과진양성을카이제곱검정과 student T 검정으로비교하여그차이가통계적으로유의한지확인하였다. 모든통계분석은 Window 용 SPSS version 10.0 통계프로그램을이용하였으며, 통계적인유의수준은 P 값이 0.05 미만인경우로하였다. 결 과 1. 연구대상의일반적특성 연구대상이었던총 231 명의피검자중에서여자가 128 명 (55.4%) 으로많았으며, 체질량지수는여자가 25.6± 2.8 kg/m 2 으로남자의 23.7±2.9 kg/m 2 보다높았다. 또한고혈압은여자가 100 명 (78.1%) 으로남자 72 명 (69.9%) 보다많았으며, 심장초음파검사상좌심실비대도역시여자가 90 명 (70.3%) 으로남자 54 명 (52.4%) 보다많았다. 심흉곽비는여자가 0.51±0.04 로남자 0.47±0.05 보다약간 높았고, 반면혈색소는남자가 14.7±1.4 g/dl 로여자의 12.9±1.1 g/dl 보다높았다. 현재흡연을하고있는남자는 39 명 (37.9%), 여자는 4 명 (3.1%) 이었고 1 주일에 3 회이상정기적으로운동을하는남자는 21 명 (20.4%), 여자는 13 명 (10.2%) 이었다 ( 표 1). 2. 심흉곽비에따른좌심실비대진단의민감도및특이도, 진단일치율 심흉곽비를 0.45, 0.5, 0.55 를기준으로살펴보았으며진단일치율은남자는심흉곽비를 0.5 로했을때 65%, 여자는 0.45 로했을때 71.1% 로가장높았다. 하지만심흉곽비를 0.45 로했을때여자에서특이도가 2.6% 로가장낮게측정되었고, 심흉곽비를 0.55 로했을때는남녀모두가장낮은진단일치율 (50.5%, 41.4%) 을보임과동시에남자에서민감도가 7.4% 로가장낮게측정되었다. 따라서심흉곽비를민감도와특이도, 진단일치율을고려하여보았을때남녀모두 0.5 를기준으로삼는것이가장좋은것으로나타났다 ( 표 2). 692 가정의학회지
김성훈외 : 노인에서좌심실비대진단을위한심흉곽비 (Cardio-thoracic Ratio) Table 2. Sensitivity, specificity, diagnostic agreement of cardiothoracic ratio by echocardiographic LVH. CT ratio 0.45 0.5 0.55 3. 심흉곽비 0.5 를기준으로했을때각변수들에따른위양성률및진음성률 심흉곽비 0.5 를기준으로할때전체적으로민감도 64.6%, 특이도 56.3%, 진단일치율은 61.5% 였다. 진음성군에서의남자의비율 81.6% 는위양성군에서의비율 Sex Sensitivity Specificity Agreement (%) (%) (%) Male 85.2 38.8 63.1 Female 100.0 2.6 71.1 Male 50.0 81.6 65.0 Female 73.3 23.7 58.6 Male 7.4 98.0 50.5 Female 21.1 89.5 41.4 LVH: left ventricular hypertrophy. 23.7% 보다유의하게높았다 (P<0.001). 신장은위양성군이 156.4±7.6 cm 로진음성군의 163.8±7.3 cm 보다신장이유의하게작았고 (P<0.001), 체질량지수 (BMI) 는위양성군의 BMI 가 24.4±3.1 로진음성군의 22.6±3.9 보다유의하게높았다 (P=0.005). 총콜레스테롤은위양성군에서는 205.0± 51.6 mg/dl 로진음성군에서의 182.7±36.6 mg/dl 보다유의하게높았지만 (P=0.02), 중성지방과 HDL 콜레스테롤은차이가없었으며, LDL 콜레스테롤은위양성군에서 130.9± 45.6 mg/dl 로진음성군의 110.1±34.2 mg/dl 보다유의하게높았다 (P=0.017) ( 표 3). 4. 심흉곽비 0.5 를기준으로했을때의각변수들에따른위음성률및진양성률 진양성군에서여자의비율 71.0% 는위음성군에서의비율 47.1% 보다유의하게높았다 (P=0.005). 신장에있어서위음성군은 160.5±7.6 cm 로진양성군의 155.2± 8.2 cm 보다유의하게컸으며 (P<0.001), 체중도위음성군에서 66.7±8.5 kg 로진양성군의 61.4±8.8 kg 보다유의하게많이나갔다 (P<0.001). 하지만, 체질량지수는두군간에 Table 3. Comparison of false positive and true negative of 0.5> cardiothoracic ratio by echocardiographic LVH. False positive (n=38) True negative (n=49) P value Sex Male (%) 9 (23.7) 40 (81.6) Female (%) 29 (76.3) 9 (18.4) <0.001* Height (cm) 156.4±7.6 163.8±7.3 <0.001 Weight (kg) 69.0±9.7 60.8±10.4 0.699 BMI (kg/m 2 ) 24.4±3.1 22.6±3.9 0.005 Waist circumference (cm) 85.4±8.4 83.1±9.0 0.231 Waist/hip ratio 0.89±0.06 0.89±0.05 0.705 Systolic BP (mmhg) 139.1±20.3 133.2±17.5 0.148 Diastolic BP (mmhg) 86.3±10.3 84.9±11.6 0.554 Hypertension ( 140/90 mmhg, %) 27 (71.1) 28 (57.1) 0.182* DM (%) 1 (2.6) 4 (8.2) 0.272* Total cholesterol (mg/dl) 205.0±51.6 182.7±36.6 0.020 Triglyceride (mg/dl) 124.2±56.8 109.2±60.5 0.243 HDL-cholesterole (mg/dl) 49.3±13.6 50.8±15.7 0.644 LDL-cholesterole (mg/dl) 130.9±45.6 110.1±34.2 0.017 Hemoglobin (g/dl) 13.5±1.6 14.1±1.6 0.103 Regular exercise ( 3 times/week, %) 5 (13.2) 7 (14.3) 0.880* Smoking (%) Non-smoker 28 (73.7) 20 (40.8) Current smoker 6 (15.8) 15 (30.6) 0.005* Ex-smoker 4 (10.5) 14 (28.6) *P value by χ 2 square, P value by student t-test, BMI: body mass index, BP: blood pressure, DM: diabetes mellitus, HDL: high-density lipoprotein, LDL: low-density lipoprotein. Vol. 28, No. 9 693
Sung Hoon Kim, et al: Cardio-thoracic Ratio (CTR) for Detection of Left Ventricular Hypertrophy (LVH) in Elderly People Table 4. Comparison of false negative and true positive of 0.5>cardiothoracic ratio by echocardiographic LVH. False negative (n=51) True positive (n=93) P value Sex Male (%) 27 (52.9) 27 (29.0) Female (%) 24 (47.1) 66 (71.0) 0.005* Height (cm) 160.5±7.6 155.2±8.2 <0.001 Weight (kg) 66.7±8.5 61.4±8.8 <0.001 BMI (kg/m 2 ) 25.9±2.5 25.5±2.7 0.362 Waist circumference (cm) 90.0±8.4 87.4±7.9 0.063 Waist/hip ratio 0.92±0.07 0.91±0.05 0.623 Systolic BP (mmhg) 142.6±19.9 144.4±21.6 0.612 Diastolic BP (mmhg) 87.0±11.4 87.2±10.7 0.921 Hypertension ( 140/90 mmhg, %) 43 (84.3) 74 (79.6) 0.485* DM (%) 14 (27.5) 15 (16.1) 0.105* Total cholesterol (mg/dl) 197.7±41.3 196.1±38.8 0.820 Triglyceride (mg/dl) 156.5±89.1 134.5±58.8 0.078 HDL-cholesterole (mg/dl) 46.6±11.1 49.0±11.3 0.218 LDL-cholesterole (mg/dl) 119.8±38.9 120.1±35.5 0.952 Hemoglobin (g/dl) 14.1±1.3 13.4±1.5 0.002 Regular exercise ( 3 times/week, %) 12 (23.5) 10 (10.8) 0.045* Smoking (%) Non-smoker 27 (52.9) 72 (77.4) Current smoker 9 (17.6) 13 (14.0) 0.004* Ex-smoker 15 (29.4) 8 (8.6) *P value by χ 2 square, P value by student t-test, BMI: body mass index, BP: blood pressure, DM: diabetes mellitus, HDL: high-density lipoprotein, LDL: low-density lipoprotein. 유의한변화가없었다. 또한혈색소수치는위음성군이 14.1±1.3 g/dl 로진양성군의 13.4±1.5 g/dl 보다유의하게높았다 (P=0.002). 진양성군의비흡연자의비율은 77.4% 로위음성군의 52.9% 보다유의하게높았다 (P= 0.004) ( 표 4). 고 단순흉부후전위촬영으로구한심흉곽비는좌심실비대의선별검사로일차의료에서널리이용되고있다. 본연구는노인인구가증가하고있는최근추세에발맞춰서우리나라노인들을대상으로좌심실비대의진단에가장적합한심흉곽비를구하고진단율에미치는인자를분석하고자한본연구결과를통해노인에서도심흉곽비를 0.5 로하는것이민감도와특이도를고려했을때가장적당한것으로나타났으며, 성별및체형, 비만도, 흡연유무, 혈색소에따라달라짐을알수있었다. Hammermeister 등 22) 에따르면, 좌심실이완기말용적과좌심실구혈률이상의지표로심흉곽비는비교적특 찰 이성은떨어지나높은민감도를보이고, 단순흉부촬영사진상의심장부피와더불어장기생존율의예측인자로중요하다고하였다. 또한정상적인노화에따른변화로남녀모두심흉곽비가유의하게증가하고 17) 노인들에게있어서심흉곽비증가로인해확인된단순흉부촬영상의심비대는남녀모두예후가불량하다고보고되기도하였다. 23) 그러므로노인에게심흉곽비는임상에서중요한지표임에틀림이없다. 본연구에서는 60세이상의노인들을대상으로한조사에서심흉곽비를 0.45를기준으로했을때, 좌심실비대에대한민감도는남자 85.2%, 여자 100%, 특이도는각각 38.8%, 2.6% 로민감도는양호하나특이도가떨어지는소견을보여심흉곽비가좌심실비대진단에는비특이적이라는 Hammermeister 등 22) 의연구결과와비슷한양상이었지만, 0.5 기준으로했을때민감도는남자 50%, 여자 73.3% 였고, 특이도는남자 81.3%, 여자 23.7% 로, 여자는 Hammermeister의연구결과와양상이비슷하였다. 하지만본연구에서는남자의경우오히려심흉곽비 0.45 기준일때보다특이도가더좋은것으로나왔다. 또 694 가정의학회지
김성훈외 : 노인에서좌심실비대진단을위한심흉곽비 (Cardio-thoracic Ratio) 한, Dreslinski 24) 는심흉곽비를 0.55 이상으로하는것이좌심실비대진단에더무난하다고하였지만, 본연구에서는심흉곽비를 0.55 로기준으로했을경우에는특이도는남녀모두양호했으나민감도가남녀모두가장낮은수치를보임에따라적정하지못한것으로판단되었다. 이는대상자가노인으로인한차이로생각된다. 따라서본연구에서는심흉곽비의기준을 0.5 로하는것이남녀의차이를고려한, 적정한민감도와특이도를만족하는기준으로판단하였다. 성별의차이에대해서는본연구에서진단일치율은심흉곽비 0.45 기준일때남자 63.1%, 여자 71.1% 였던것이 0.5 기준일때는남자가 65% 로별차이가없는반면, 여자는 58.6% 로오히려감소한것으로나타났다. 이것은성별에의한차이와몸무게의영향으로생각한다. Olivetti 등 25) 에따르면여자에서는노화가심근세포의소실과심근세포의반동적인비대를야기하지않는다고하였으며, 반면에남자는매년 1 g 가량의심근세포가소실되면서매년 158μm 3 정도의속도로심근세포의부피가커지는성별의차이를보고한바있다. 이는정상적인노화에따른심장의변화에있어서성별에따른차이가있음을의미하는것으로서본연구에서의특정심흉곽비기준으로성별에따른좌심실비대의진단일치율의차이와도부합한다고볼수있겠다. 본연구대상자들의과반수는고혈압을진단받은바있었는데, Rayner 등 26) 은심흉곽비가나이와관련있으나임상적인혈압과의관련성은통계학적인의미가없다고하였고, 본연구에서도역시좌심실비대의진단에있어서고혈압이위양성및위음성에관한한통계학적의미는없었다. 비만도에있어서본연구에서는비만할수록특이도가낮고위양성률이높게나타났으나, 위음성률과진양성률간에유의한차이가없었다. 따라서좌심실비대가없는사람에서심흉곽비는비만도에영향을받지않는것으로보인다. 혈색소수치에있어서혈색소수치가낮을수록민감도가높게나타났는데, 일반적으로혈색소수치가낮아서빈혈이있는경우빈혈에대한생체보상기전으로혈압이상승하고혈장량이늘어나게되면서좌심실비대가악화되어 27) 쉽게좌심실비대진단될수있으나빈혈이없는경우는이러한작용들이없기때문에상대적으로위음성률이더높은것으로생각한다. 비흡연군에서흡연군보다진양성률에있어서통계학적으로유의한차이를보였는데, Herman 28) 은만성폐쇄성폐질환이있을경우횡격막이아래로쳐지고흉곽이길어져서심흉곽비가 0.5 이하라도부검상심비대가증명되는등, 단순흉부촬영상으로심비대를진단하기어 려워진다고하였다. 이것은흡연이폐의폐기종성변화를일으키고, 결국만성폐쇄성폐질환의특성을보이면서횡격막이쳐지고흉곽이길어지면서상대적으로심흉곽비가감소하기때문에 28) 진양성률이낮은것으로생각한다. 이연구의제한점으로는첫째, 일개종합병원종합건진센터에서자료를모았기때문에대한민국의노인인구를대표한다고는볼수없을것이다. 실제로연구대상자에서고혈압환자가남녀각각 69.9%, 78.1% 나되고좌심실비대도 52.4%, 70.3% 로높았다. 그러나임상에서는주로고혈압환자에서심흉곽비를좌심실비대의선별검사로이용하게되므로이러한형태의연구도의미가있을수있다고할수있겠다. 두번째로는연구대상자들이고혈압, 당뇨병, 흡연, 운동등의병력을자기기입식설문지로기록했으므로자료수집에미흡한점이있으나, 의사의진찰과정을통해어느정도보충하여오차를줄이려고했지만, 역시정확한정보는아니었으리라생각한다. 그러나이연구는비록검진대상자이기는하지만일반노인인구를대상으로각각의심흉곽비에따른민감도와특이도를조사하고가장효과적인좌심실비대의심흉곽비기준을살펴본연구라는점에서의의가있을수있겠다. 1999 년보건복지부가발표한 1998 년도국민건강영양조사결과보고서 29) 에따르면도시와농촌의고혈압유병률이각각 55.1%, 50.9% 로차이를보이고있으므로좌심실비대유병률과더불어심흉곽비에서도약간의차이가있을것으로보여진다. 따라서본연구를시행했던병원의위치학적특성상농어촌지역이대부분임을감안했을때향후도시와농어촌의노인인구를모두포함한연구가필요할것으로보인다. 이것으로보아노인에서심흉곽비로좌심실비대를진단할때는기존의기준치와같게 0.5 으로정하는것이좋았으며, 이때민감도 64.6%, 특이도 56.3%, 진단일치율은 61.5% 였다. 심흉곽비를 0.5 로하였을때키가작을수록, 체질량지수가높을수록, 총콜레스테롤과 LDL 콜레스테롤이높을수록위양성률이높아지고, 키가클수록, 혈색소수치가높을수록위음성률이높게나타나므로해석에유의할필요가있겠다. 향후에는이연구와같이일개종합병원의검진대상자가아닌일반인을대상으로한연구, 그리고전국각지의여러의료기관과의공동연구를통하여지역사회, 더나아가대한민국을대표하는연구가필요할것이다. Vol. 28, No. 9 695
Sung Hoon Kim, et al: Cardio-thoracic Ratio (CTR) for Detection of Left Ventricular Hypertrophy (LVH) in Elderly People ABSTRACTS Cardio-thoracic Ratio (CTR) for Detection of Left Ventricular Hypertrophy (LVH) in Elderly People Sung Hoon Kim, M.D., Yun Jeong Shin, M.D., Hee Suk Kang, M.D., Hai Gyung Yoon, M.D., Mi Kyeong Oh, M.D., Sang Sig Cheong, M.D.* Departments of Family Medicine, *Cardiology, Gangneung Asan Hospital, University of Ulsan College of Medicine, Gangneung, Korea Background: Left ventricular hypertrophy (LVH) is closely related with a high death rate, rhythmia, ischemic heart disease, stroke and sudden death. It is known that the prognosis becomes better as LVH regresses. Therefore, it is important to diagnose it correctly with ease in primary care. The authors evaluated the most standard cardio-thoracic ratio (CTR) with respect to LVH oriented towards elderly people whose body habitus changed over time as they had become older, and evaluated the factors which affect the rate of diagnosis including sensitivity and specificity. Methods: A total of 231 subjects over 60 years of age who visited a general hospital health promotion center from March 1997 to August 2003, underwent echocardiography and identified not to have heart disease were selected. LV (left vetricular) mass was measured through echocardiography. LV mass was divided by 2.7 times of height (m) by Deveruex's method, and 49.1 g/m 2.7 for men and 46.7 g/m 2.7 for women were set to be standards of LVH. CTR was obtained by dividing the maximum transverse diameter of the heart by maximum transverse diameter of thorax on chest PA. Results: CTR was observed on the basis of 0.45, 0.5, 0.55, and the agreement was highest of 0.5 for men and 0.45 for women. However, considering the sensitivity, the specificity, and the positive predictive value, it was thought to be most proper to be set at 0.5 was be standard for both men and women. When diagnosing LVH through chest PA, if 0.5 was set to be standard, false positive become high in women, false negative became high as height increased, and false negative became high as body mass index (BMI) increased. The smoking group showed higher false negative compared to the nonsmoking group, and the false negative was higher as the level of hemoglobin increased. Conclusion: When diagnosing LVH through CTR in elderly people, it was appropriate to set 0.5 as a standard, but it is necessary to consider sex, body habitus, BMI, smoking and the level of hemoglobin. (J Korean Acad Fam Med 2007;28:690-697) Key words: left ventricular hypertrophy, cardio-thoracic ratio, elderly people, echocardiography, sensitivity, specificity 참고문헌 1. Hemingway H, Shipley M, Christie D, Marmot M. Is cardiothoracic ratio in healthy middle aged men an independent predictor of coronary heart disease mortality? Whitehall study 25 year follow up. BMJ 1998;316:1353-4. 2. Hart CL, Hole DJ, Smith GD. Comparison of risk factors for stroke incidence and stroke mortality in 20 years of follow-up in men and women in the Renfrew/Paisley Study in Scotland. Stroke 2000;31:1893-6. 3. Haider AW, Larson MG, Benjamin EJ, Levy D. Increased left ventricular mass and hypertrophy are associated with increased risk for sudden death. J Am Coll Cardiol 1998;32:1454-9. 4. Gardin JM, Lauer MS. Left ventricular hypertrophy: The next treatable, silent killer? JAMA 2004;292:2396-8. 5. Vasan RS, Larson MG, Benjamin EJ, Evans JC, Levy D. Left ventricular dilatation and the risk of congestive heart failure in people without myocardial infarction. N Engl J Med 1997;336:1350-5. 6. Cohn JN, Johnson GR, Shabetai R, Loeb H, Tristani F, Rector T, et al. Ejection fraction, peak exercise oxygen consumption, cardiothoracic ratio, ventricular arryhthmias, and plasma norepinephrine as determinants of prognosis in heart failure. Circulation 1993;87 Suppl 6:5-16. 7. 오미경. 일차의료에서이용할수있는심혈관질환예측인자들의새로운관점. 가정의학회지 2005;26 Suppl 11:67-73. 8. de Simone G, Devereux RB, Roman MJ, Alderman MH, Laragh JH. Relation of obesity and gender to left ventricular hypertrophy in normotensive and hypertensive adults. Hypertension 1994;23(5):600-6. 9. Ganau A, Saba PS, Roman MJ, de Simone G, Realdi G, Devereux RB. Ageing induces left ventricular concentric remodelling in normotensive subjects. J Hypertens 1995;13(12 Pt 2):1818-22. 696 가정의학회지
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