원저 Korean Circulation J 2004;34(11):1099-1106 치료전고혈압환자에서일중혈압의변화양상과맥파전도속도및좌심실확장기기능과의관계 고려대학교의과대학내과학교실 송우혁 안정천 김진원 나승운 박희남 임도선김영훈 심완주 박창규 서홍석 오동주 노영무 Relation between Pulse Wave Velocity, Left Ventricular Diastolic Function, and Circadian Variation of Blood Pressure in Patients with Never Treated Essential Hypertension Woo Hyuk Song, MD, Jeong Cheon Ahn, MD, Jin Won Kim, MD, Seung Woon Rha, MD, Hee Nam Park, MD, Do Sun Lim, MD, Young Hoon Kim, MD, Wan Joo Shim, MD, Chang Gyu Park, MD, Hong Seok Seo, MD, Dong Joo Oh, MD and Young Moo Rho, MD Department of Internal Medicine, College of Medicine, Korea University, Seoul, Korea ABSTRACT Background and Objectives:An increased pulse wave velocity (PWV) and a non-dipping pattern in hypertensive patients have been shown to be associated with an excess of target organ damage. The relationship between the PWV and circadian variation of blood pressure (BP) (dipper or nondipper) were sought, and also the LV diastolic function between dipper and nondipper patients compared. Subjects and Methods:44 hypertensive subjects, who had never been treated, were enrolled (mean age: 48±12 yrs, men: 29). The following procedures were undertaken. 1) 24 hour ambulatory BP monitoring; 2) echocardiography for LV geometry, LV mass index (LVMI), LV systolic and diastolic functions, including tissue Doppler and aortic PWV. The patients were divided into two groups with respect to their ambulatory BP profiles, i.e., dipper and nondipper. The PWV, LV geometry and diastolic functions were compared between dipper and nondipper patients, and the relationship between the PWV and diastolic function analyzed in all patients. Results:Twenty (45%) were nondipper patients. There were no significant differences in the LV geometry, LVMI and PWV between dipper and nondipper patients (PWV; 8.8±3.1 vs. 8.6±3.3 m/sec, p>0.05). In all patients, the PWV was related to the deceleration time (r=0.34, p=0.03) and the mitral E/A (r=-0.31, p=0.02) and mitral Em/Am ratios obtained by the tissue Doppler echocardiography (r=-0.31, p=0.03). The proportion with diastolic dysfunction was higher in the nondipper than the dipper patients (21 vs. 50%, p<0.01). There was a significant relation between the PWV and Em (r=-0.45, p=0.047) in the nondipper, but not in the dipper. Conclusion:Prolonged exposure to high BP (nondipper) was not related with increased aortic stiffness in never treated hypertensive patients. The PWV was closely related with LV diastolic dysfunction in nondipper patients. (Korean Circulation J 2004;34(11):1099-1106) KEY WORDS:Hypertension;Cardiac function tests. 논문접수일 :2004 년 7 월 21 일수정논문접수일 :2004 년 8 월 26 일심사완료일 :2004 년 9 월 20 일교신저자 : 안정천, 425-020 경기도안산시단원구고잔 1 동 516 고려대학교의과대학내과학교실전화 :(031) 412-5982 전송 :(031) 412-5594 E-mail:hhansin@korea.ac.kr 1099
서론 맥파전도속도 (pulse wave velocity, PWV) 는대동맥의경직도 (aortic stiffness) 를대표하는지표로서맥파전도속도가증가할경우심혈관계질환으로인한사망률이증가한다. 1)2) 맥파전도속도에영향을미치는요소로맥박수는비교적영향이적고, 3) 나이, 성별, 대동맥의동맥경화 (atherosclerosis) 정도, 그리고혈압등 4) 이주로관여하는데고혈압환자에서고혈압의조절정도에따라맥파전도속도의변화를추적관찰한결과혈압조절이효과적으로이루어졌을경우맥파전도속도의증가가둔화되고 5) 일부의안지오텐신수용체차단제와같은항고혈압약물은혈압강하효과와는별개로맥파전도속도를감소시키는효과가있다. 6) 또한고혈압환자에서 24 시간혈압측정 (ambulatory blood pressure monitoring) 을통해야간의평균혈압이주간보다 10% 이상감소한환자군 (dipper) 에서그렇지않은환자군 (nondipper) 보다심혈관질환의발병빈도나예후가양호하며 7) nondipper에서동맥경화의정도가크다는보고 8) 가있다. 이러한결과들은고혈압에노출되는시간이적을수록대동맥경직도의증가를감소시키고표적장기의손상정도를줄일가능성이높다는점을시사한다. 하지만상대적으로지속적인고혈압에노출되는 nondipper와그렇지않은 dipper 사이에발생할수있는맥파전도속도의차이에대해서는보고된바없다. 또한 nondipper 에서좌심실비대나 eccentric hypertrophy 를일으키는경향이있고일반적으로좌심실비대는확장기기능부전을잘동반하지만 9) dipper와 nondipper 간에좌심실의확장기기능의차이에대한직접적인차이는잘알려져있지않다. 이에본연구에서는약물의투여에의한대동맥경직도의변화를배제하고자고혈압으로진단받았으나항고혈압제의투약경력이없던환자를대상으로 24시간혈압측정을통한 dipper 와 nondipper 간에대동맥경직도및좌심실확장기기능의차이가존재하는지를관찰하였으며더불어대동맥경직도와좌심실확장기기능의연관관계를살피고자하였다. 대상및방법 대상고혈압으로진단 ( 140/90 mmhg) 된후항고혈압제 1100 의투약경력이없으며외래에서 24시간혈압을측정하여평균혈압 125/80 mmhg 인환자를대상으로하였다. 당뇨, 신부전이있거나중등도이상의판막질환, 좌심실구혈율이 55% 이하, 관상동맥질환의병력, 뇌경색, 만성폐질환, 피임약이나호르몬대치요법, 심방세동, 백의고혈압 (white-coat hypertension) 등이있거나심장초음파의영상이부적절한환자는대상에서제외하였다. 방법 24시간혈압측정은평일에이루어졌으며환자는정상적일상생활을하도록권유하였다. 주간 (day time) 은오전 7:00시 ~ 저녁 11:00시로분류하고혈압의측정은주간에는매 20분마다, 야간 (night time) 에는매 30 분마다측정하였다. 그결과에따라야간의평균혈압이주간의평균혈압보다 10% 이상감소하는경우를 dipper로, 그렇지않은경우를 nondipper로분류하였다. 좌심실의모양및수축기, 확장기기능, 그리고맥파전도속도는심장초음파 (Sequoia 236, Acuson, USA) 에부착된 2.5 MHz 탐촉자를이용하여검사하였다. 검사당일환자는흡연자의경우검사전 24시간이상금연하도록하였고키와몸무게를측정하고 20 분이상안정후좌위에서혈압과맥박을 3회이상측정하였다. 그후심장초음파를시행하여 2-D mode 에서좌심실구혈율 (ejection fraction) 을얻었으며, M-mode 에서수축기말좌심실내경 (left ventricular end systolic dimension, LVESD) 및확장기말좌심실내경 (left ventricular end diastolic dimension, LVEDD), 좌심실중격두께 (inteventricualr septal thickness, IVST) 과좌심실후벽두께 (posterior wall thickness, PWT) 를측정하여다음과같은공식으로좌심실질량 (left ventricular mass) 를측정하였다. left ventricular mass(g)=1.04[(lvedd+ivst+ PWT) 3 -LVEDD 3 ] 연후에환자의키와몸무게를이용하여환자의체표면적을얻고이를이용해좌심실질량을표준화하여좌심실질량지수 (left ventricular mass index;g/m 2, LVMI) 를구하였다. 좌심실의확장기기능은간헐파형도플러 (pulse wave Doppler) 를이용하여얻었는데승모판에서의초기이완 Korean Circulation J 2004;34(11):1099-1106
기혈류속도 (E), 후기이완기속도 (A), deceleration time (DT), isovolumic relaxation time(ivrt) 등을측정하고조직도플러초음파검사 (tissue doppler echocardiography) 를이용하여승모판륜의초기이완기속도 (Em) 와후기이완기속도 (Am) 를구하였다. 맥파전도속도는 foot-to-foot methods 10) 를이용하였는데근위부의측정은앙와위 (supine position) 에서 2.5 MHz의심장초음파탐촉자를흉골상절흔 (suprasternal notch) 에위치한후좌측쇄골하동맥 (subclavian artery) 기시부바로이하부위를 sample vloume 으로하여간헐파형도플러 (pulse wave doppler) 로 aortic flow velocity 를측정하고심장초음파에부착된심전도상의 R파와간헐파형도플러에서측정된혈류가나타나기시작하는시간 (T1) 을측정하였으며복부에서하행대동맥의분지 (aortic bifurcation) 상부를 sample volume 으로하여동일한방법으로 R파의출현후혈류가나타나는시간 (T2) 을측정하고양측정부위사이에서혈류가나타나기시작하는시간의차이 (T1-T2) 를얻은후이를양측정부위사이의거리 (D) 로나누어 PWV (m/sec) 를구하였다 (PWV=D/T1-T2). 통계적분석모든측정값은평균 ± 표준오차로나타내었고 SPSS (version 11.5.0 for Windows(SPSS Inc)) 통계프로그램을이용하였다. Dipper와 nondipper 간에맥파전도속도의차이는 independent sample t-test를이용하여검증하였으며, 맥파전도속도와좌심실확장기능을나타내는각각의표지자와의관계는상관분석 (correlation analysis) 과회귀분석 (regression analysis) 을시행하였다. 각군에서좌심실확장기능부전환자의발생빈도의차이는 chisquare test 로검증하였다. 결과 임상적특성및양군간좌심실확장기능의비교대상환자는총 44 명으로이중 dipper가 24명 (54.5%) 이었으며나이 (dipper:45.3±9.2 yrs, nondipper: 48.5±4.9 yrs, p>0.05) 와성별 (dipper; 남 :15명 (62%);nondipper; 남 :14명(70%), p>0.05) 은양군간유의한차이가없었다. Dipper와 nondipper 사이에 24시 간평균수축기혈압 (139.5±12.7 mmhg vs 135.1± 15.2 mmhg, p>0.05) 과주간수축기혈압역시양군간유의한차이는없었지만, 확장기혈압은 dipper에서 nondipper 군보다유의하게상승되어있었다 (99.0±8.6 mmhg vs 91.5±12.9 mmhg, p=0.03). 심장초음파상의좌심실질량지수 (LVMI), 좌심실의확장기및수축기내경, 좌심방의내경등도양군간특별한차이가없었으며, 간헐파형도플러로측정한좌심실의확장기능지표역시 DT(dipper;198.3±21.3 msec vs nondipper;218±0.3 msec, p=0.03) 를제외하고는양군간유의한차이를보이지않았다 (Table 1, 2). 하지만 dipper 와 nondipper에서좌심실확장기기능 (diastolic function) 에따라대상환자를정상이완기능 (normal diastolic filling pattern), abnormal relaxation, pseudonormal filling pattern 11) 으로나누었을때대상환자수는 dipper Table 1. Characteristics of study patients Dipper (n=24) Nondipper (n=20) Men (%) 15 (62) 14 (72) NS Age (yrs) 045.3±09.2 048.5±14.0 NS 24ASBP (mmhg) 139.1±12.7 135.1±15.2 NS 24ADBP (mmhg) 093.8±07.9 089.8±12.7 NS DASBP (mmhg) 145.5±13.5 137.3±15.7 NS DADBP (mmhg) 099.0±08.6 091.5±12.9 0.027 NASBP (mmhg) 125.8±11.9 130.2±14.8 NS NADBP (mmhg) 083.4±07.6 086.0±12.6 NS Duration of HTN 007.2±03.5 008.4±06.1 NS (months) Current smoker (%) 35.2 37 NS Heart rate 071.3±07.6 072.5±10.4 NS (beat/min) SBP (mmhg) 0.151±07.1 0.153±09.4 NS DBP (mmhg) 096.4±07.9 093.2±09.5 NS Blood glucose (g/dl) 109.4±13.1 112.4±14.3 NS Total cholesterol 182.8±23.7 178.1±28.6 NS (mg/dl) Serum creatinine 000.9±00.2 001.0±00.3 NS (mg/dl) Body weight (kg) 069.6±06.5 070.4±13.4 NS Height (cm) 165.0±07.0 165.5±09.9 NS BMI (kg/m 2 ) 025.6±02.2 025.6±03.5 NS HTN: hypertension, 24ASBP: 24 hr average systolic blood pressure, 24ADBP: 24 hr average diastolic blood pressure, DASBP: daytime average systolic blood pressure, DADBP: daytime average diastolic blood pressure, NASBP: night time average systolic blood pressure, NADBP: night time average diastolic blood pressure, SBP: systolic blood pressure, DBP: diastolic blood pressure, BMI: body mass index p 1101
Table 2. Echocardiographic findings of the study patients Dipper (n=24) Nondipper (n=20) LVDd (mm) 049.2±02.6 048.7±04.3 NS LVSd (mm) 032.5±02.8 031.5±03.7 NS IVST (mm) 009.7±00.8 009.2±00.9 NS PWT (mm) 009.6±00.5 009.7±00.7 NS EF (%) 059.7±03.6 057.1±03.9 NS LVMI (g/m 2 ) 105.2±17.8 102.4±26.5 NS E/A 001.1±00.2 001.0±00.3 NS DT (ms) 198.3±21.3 0.218±00.3 0.03 IVRT (ms) 093.0±13.6 095.3±19.5 NS Em (cm/sec) 15.45±0.03 14.45±0.05 NS Am (cm/sec) 14.09±0.03 14.20±0.02 NS Em/Am 001.1±00.3 001.0±0.43 NS PWV (m/s) 008.8±03.1 008.6±03.3 NS LVDd: left ventricular diastolic dimension, LVDSd: left ventricular systolic dimension IVST: interventricular septal thickness, PWT: posterior wall thickness, EF: echocardiographic findings, LVMI: left ventricular mass index, DT: deceleration time, IVRT: isovolumetic relaxation time, Em: tissue Doppler measured mitral early E wave, Am: tissue Doppler measured mitral late A wave, PWV: pulse wave velocity 100% 090% 080% 070% 060% 050% 040% 030% 020% 010% 000% n=4 n=1 n=19 Dipper p<0.001 n=9 n=1 n=10 Nondipper 에서각각 19명 (79%), 4명 (16.6%), 1명 (4.4%) 이었으며 nondipper 군에서는각각 10명 (50%), 9명 (5%), 1명 (45%) 으로유의하게 nondipper 군에서확장기기능의장애발생빈도가높았다 (p<0.05, Fig. 1). Dipper 및 non-dipper 환자간대동맥파전도속도와의관계심장초음파로맥파전도속도를구할당시수축기및확 p AR PN N Fig. 1. Distribution of diastolic filling pattern within dipper and nondipper. AR: abnormal relaxation, PN: pseudonormal, N: normal. Table 3. Correlation coefficient of PWV with various AMBP parameters Dipper (n=24) Nondipper (n=20) Total (n=44) PWV p PWV p PWV p 24ASBP -0.04 NS -0.08 NS -0.04 NS 24ADBP -0.06 NS -0.12 NS -0.06 NS PP -0.04 NS -0.05 NS -0.01 NS DASBP -0.07 NS -0.12 NS -0.08 NS DADBP -0.01 NS -0.13 NS -0.15 NS NASBP -0.22 NS -0.05 NS -0.28 NS NADBP -0.17 NS -0.14 NS -0.01 NS PWV: pulse wave velocity, AMBP: ambulatory blood pressure monitoring, 24ASBP: 24 hr average systolic blood pressure, 24ADBP: 24hr average diastolic blood pressure, DASBP: daytime average systolic blood pressure, DADBP: daytime average diastolic blood pressure, NASBP: night time average diastolic blood pressure, NADBP: night time average diastolic blood pressure, PP: pulse pressure 장기혈압과맥박수는양군간유의한차이가없었다 (Dipper; 혈압 142±8.2/92.0±9.8 mmhg, 맥박수 82.4± 5.7/ 분, nondipper; 혈압 144.3±24/90.2±16.9 mmhg, 맥박수 79±3.3/ 분, p>0.05). 맥파전도속도는 dipper 군에서 8.8±3.1 m/sec, nondipper 군에서는 8.6±3.3 m/sec 로양군간유의한차이는관찰되지않았다. 혈압과맥파전도속도와의관계를좀더규명하기위해각군내에서 24시간평균혈압및주간과야간의평균수축기혈압및평균확장기혈압, 맥압 (pulse pressure) 등과맥파전도속도의상관관계를관찰하였지만역시특별한관계는없었다 (Table 3). 맥파전도속도와좌심실확장기능과의상관관계각군에서맥파전도속도와좌심실확장기기능간의회귀분석에서 dipper 군에서는맥파전도속도와좌심실확장기기능을나타내는지표들과는유의한상관관계가없었던반면 (E:r=-0.24, A:r=0.01, E/A:r=-0.19, Em:r=0.26, Am:r=0.28, Em/Am:r=-0.2, E/ Em:r=-0.35:p>0.05 with all variables), nondipper 군에서는간헐파도플러로측정한승모판막확장기혈류의 A파가맥파전도속도와유의한상관관계를보여주었으며 (r=0.524, p= 0.018), 조직도플러를이용해측정한승모판륜 E파 (Em) 와맥파전도속도가유의한상관관계를보여주었다 (r=0.44, p=0.047, Fig. 2). 전체대상환자에서맥파전도속도는 deceleration time(r=0.34, 1102 Korean Circulation J 2004;34(11):1099-1106
0.30 1.1 Em 0.25 0.20 0.15 0.10 r=-0.45 p=0.04 Mitral A wave 1.0 0.9 0.8 0.7 0.6 r=0.524 p=0.018 0.05 0.5 0.00 2 4 6 8 10 12 14 16 18 PWV 0.4 2 4 6 8 10 12 14 16 18 PWV Fig. 2. Linear regression curves between pulse wave velocity (PWV,m/sec) and mitral A wave velocity (m/sec), and tissue doppler measured mitral E velocity (Em,m/sec) in nondipper. DT(ms) 320 r=0.34 300 p=0.03 280 260 240 220 200 180 160 140 0 5 10 15 20 25 30 E/A ratio 1.8 1.6 1.4 1.2 1.0 0.8 r=-0.31 p=0.02 0.6 0.4 0 5 10 15 20 25 30 PWV (m/sec) IVRT (ms) 180 160 140 120 100 080 r=0.17 p=ns 060 0 5 10 15 20 25 30 PWV (m/sec) Em/Am ratio 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 r=-0.31 p=0.03 0 5 10 15 20 25 30 PWV (m/sec) Fig. 3. Linear regression curves of the relation between pulse wave velocity (PWV) and left ventricular isovolumic relaxation time (IVRT), deceleration time (DT), mitral E/A ratio, and tissue doppler measured mitral Em/Am ratio in the total patients. p=0.03), E/A ratio(r=-0.31, p=0.02), 그리고조직도플러로측정한 Em/Am ratio(r=-0.31, p=0.03) 와유의한상관관계를보여주었다 (Fig. 3). 고찰 본연구에서고혈압으로항고혈압제를투약받은경력이없는환자에서 24 시간혈압으로측정한 dipper 와 nondipper 간맥파전도속도는유의한차이가없었다. 고혈압환자에서정상혈압인사람보다대동맥의경직도가증가되어있으며, 12) 고혈압이혈관의동맥경화를촉진시키고, 13) nondipper 환자군에서내피세포의산화질소 (NO) 방출이 dipper보다감소되어있다는보고가있다. 14) 이러한연구결과들은보다지속적으로고혈압에노출되는 nondipper에서대동맥의경직도가상대적으로증가되어있을가능성을시사하지만아직까지 nondipper 및 dipper 환자군에서맥파전도속도로대변되는대동맥경직도의상호간비교를통하여혈압의일중변동 1103
양상이혈관에미치는영향은알려져있지않다. 이에저자등은일중혈압의변동양상에따른맥파전도속도의차이를규명하고자하였는데본연구의결과는예상과달리양군간에맥파전도속도가유의한차이를보이지않았다. 이러한결과가나온원인으로몇가지가능성을고려할수있다. 첫째, 연구대상환자군의고혈압유병기간이짧아혈압의일중변동이아직대동맥의구조적혹은기능적이상을발현시킬만큼영향을미치지않았거나둘째, 인위적으로야간의혈압이주간에비해 10% 이상감소하는것을기준으로하여나눈 dipper 와 nondipper 의분류가심장에미치는영향과는달리환자의맥파전도속도로대변되는대동맥경직도에영향을미칠만큼의미있는분류가아닐경우의가능성, 셋째로 24 시간혈압의측정자체의재현성 (reproducibility) 이떨어져 dipper와 nondipper의명확한구분이힘들경우를생각할수있겠다. 두번째가능성의경우 24시간활동혈압측정이일상및수면중에보다많은혈압측정의기회를제공하여단순한혈압측정보다고혈압환자의진단및예후의판정에유용하다는 7)15) 것은잘알려져있지만 nondipper와목표장기의손상정도와의관계에대한상반된보고들 16)17) 이있으며또한좌심실비대나경동맥의동맥경화정도의차이가주간과야간의혈압차이에기인한다기보다는전체적인혈압정도와관계있다는보고 18) 도있어본연구에서처럼 nondipper와 dipper 간대동맥경직도를포함한목표장기 (target organ) 의손상정도와의차이는불분명한점이있다. 24시간혈압측정의재현성에대해서는 Cuspidi 등 19) 이 4주간격으로시행한 24시간활동혈압검사상처음에 dipper로분류된환자중 20.4% 가재검결과 nondipper로분류되었다고보고한바있다. 하지만지속적인 nondipper로분류된환자들은지속적인 dipper로분류된환자들에비해좌심실의구조적변화가뚜렷하여혈압이 non-dipping 양상을보일경우심혈관질환의위험예측에도움이될수있다고하였다. 본연구의대상환자가많지않아이러한변화가본연구에서도나타났다고가정한다면연구결과에영향을미쳤을가능성이있을것으로사료된다. 본연구결과는고혈압의유병기간이짧지만치료받지않은고혈압환자에서야간의혈압강하여부는좌심실질량지수 (left ventricular mass index) 를비롯한좌심실모양 (left ventricular geometry) 이나대동맥경 1104 직도와특별한상관관계가없는것으로나타났다. 하지만본연구의대상환자들이고혈압의유병기간이비교적짧고다른연구들에서 Balci 등 20) 에따르면 nondipper 에서 dipper 에비해좌심실의 eccentric hypertrophy 가증가되어있고 Glen 등 21) 은백의고혈압환자의일부에서조기혈압조절을필요로하는심혈관질환이발생하였다고보고한바있으며반대로혈액투석중인고혈압환자에서 nondipper와 dipper 간좌심실비대의특별한차이는나타나지않았다는보고도있어 18) 본연구의결과만으로 dipper에서표적장기의손상이 nondipper 와차이가없을것이라는결론은성급한것으로사료된다. 본연구의전체대상 (n=44) 에서맥파전도속도는좌심실의확장기기능과밀접한관계를나타냈는데맥파전도속도가증가될수록확장기기능이감소하는음의상관관계 (negative correlation) 를보여주었다 (Fig. 3). 이는최근에 Eren 등 12) 의고혈압환자와당뇨환자를대상으로한연구결과에서대동맥의긴장도 (aortic strain) 가 IVRT(isovolumic relaxation time) 나승모판막이완기혈류속도비 (E/A ratio), DT(deceleration time) 등의좌심실이완기기능지표와밀접한관계를가진다는보고와유사하다. 이들은이러한현상이아마도고혈압자체가심장과혈관에동시에영향을미쳐나타나는현상일뿐맥파전도속도와좌심실의확장기기능은직접적인관계가없거나혹은다른하나의가능성으로맥파전도속도가증가되면서좌심실의후부하 (afterload) 를증가시켜좌심실의수축기말압력을증가시키는효과 22)23) 를가져오게되고이러한좌심실의수축기말압력을감소시키려는기전이좌심실의구조적변화를초래해결과적으로좌심실의확장기기능장애를유발하는것으로설명하였다. Eren 등 12) 의연구와본연구의차이는본연구에서는대상이항고혈압제를투여받은적이없으며비교적고혈압의유병기간이짧은초기고혈압환자를대상으로한점이며, 본연구에서고혈압의초기에맥파전도속도에영향을미칠수있는약물의효과를배제한상황에서도맥파전도속도가좌심실의확장기기능과밀접한관계가있었다. 본연구에서다른하나의흥미로운점은 dipper 군과 nondipper 군으로나누어맥파전도속도와좌심실확장기기능과의관계를살펴보았을때 dipper 군에서는맥파전도속도와좌심실확장기기능사이에특별한관계가없었던반면, nondipper 군에서는 Korean Circulation J 2004;34(11):1099-1106
맥파전도속도와조직도플러로측정한승모판륜의초기이완기속도가맥파전도속도와유의한음의상관관계를지니고있고 (r=-0.45, p<0.05), E/Em ratio는특별한관계가없었다는점이다. Em 은좌심실확장기기능의 active process 를대변하는 tau(time constant of isovolumic relaxation) 와밀접한양의상관관계가있으며, E/ Em은좌심실확장기압을예측하는지표이다. 24)25) 따라서 dipper와같은지속적혈압상승조건에서맥파전도속도의상승, 즉대동맥경직도의증가가좌심실의후부하를증가시킴으로서좌심실의에너지대사에먼저문제를초래하고결과적으로좌심실의초기이완기의 active process 에기능부전을가져올가능성이높다. 결론적으로항고혈압제를투여받은경력이없는고혈압환자에서대동맥파전도속도는혈압의야간감소여부와유의한관계는없었지만좌심실의확장기기능부전과밀접한상관관계를나타내었으며특히 dipper 에서좌심실이완기초기의 active process 의기능부전양상과관계가깊다. 요약 배경및목적 : 고혈압환자중 nondipper에서목표장기의손상이증가하고심혈관계질환발생의위험성이높은것으로알려져있다. 맥파전도속도는지속적으로고혈압에노출되는 nondipper 에서 dipper 보다증가되어있을것으로추측되나아직이에대한연구는보고된바없으며, 맥파전도속도와좌심실확장기기능과의상관관계역시잘알려져있지않다. 이에저자등은치료전고혈압환자에서일중혈압의변화양상이맥파전도속도에미치는영향과맥파전도속도가좌심실확장기기능에미치는영향을평가하고자하였다. 방법 : 고혈압으로진단받았으나다른질환의증거가없으며항고혈압제를복용한적이없는 44 명의환자 ( 평균고혈압유병기간 :7.9±4.7월, 나이 :48±12 세, 남자 :29) 를대상으로하였다. 대상환자는 24시간활동혈압검사를시행하여 dipper(n=24) 와 nondipper(n=20) 로구분하였으며, 심장초음파검사로좌심실질량지수 (left ventricular mass index), 수축기및확장기좌심실내경, 좌심실두께등을측정하였다. 맥파전도속도는하행대동맥 과복부대동맥에서 foot-to-foot method 를이용하여측정하였고좌심실의확장기기능은확장기승모판혈류양상 (E wave, A wave, E/A ratio) 및 DT(deceleration time), IVRT(isovolumic relaxation time), 조직도플러 (tissue dopper) 를이용해승모판륜에서의초기이완기속도 (Em) 와후기이완기속도 (Am) 등을측정하였다. 결과 : Dipper 및 nondipper 간고혈압유병기간, 나이, 심장초음파시행당시의혈압, 맥박수등은유의한차이가없었다. 양군간좌심실질량이나맥파전도속도역시유의한차이를보이지않았다 ( 맥파전도속도 dipper;8.8± 3.1 m/sec vs nondipper;8.6±3.3 m/sec, p>0.05). 하지만전체에서맥파전도속도는 DT(r=0.34, p=0.03), mitral E/A ratio(r=-0.31, p=0.02), 그리고조직도플러심장초음파로측정한 mitral Em/Am ratio(r=-0.31, p=0.03) 등과유의한상관관계를보였다. Nondipper 군에서 dipper 군에비해좌심실확장기기능부전환자가유의하게많았으며 (21% vs 50%, p<0.01) 맥파전도속도는 nondipper 군에서조직도플러상 mitral Em (r=-0.45, p=0.047) 과유의한상관관계를보였다. 결론 : 치료전고혈압환자에서일중혈압의변화정도는맥파전도속도로대변되는대동맥경직도에유의한영향을미치지는않으나 nondipper에서대동맥경직도와좌심실확장기기능부전과유의한관련이있었다. 중심단어 : 고혈압 ; 심기능검사. REFERENCES 1) Blacher J, Safar ME, Guerin AP, Pannier B, Marchais SJ, London GM. Aortic pulse wave velocity index and mortality in end-stage renal disease. Kidney Int 2003;63:1852-60. 2) Laurent S, Boutouyrie P, Asmar R, Gautier I, Laloux B, Guize L, Ducimetiere P, Benetos, A. Aortic stiffness is an independent predictor of all-cause and cardiovascular mortality in hypertensive patients. Hypertension 2001;37:1236-41. 3) Liang YL, Gatzka CD, Du XJ, Cameron JD, Kingwell BA, Dart AM. Effects of heart rate on arterial compliance in men. Clin Exp Pharmacol Physiol 1999;26:342-6. 4) Farrar DJ, Bond MG, Riley WA, Sawyer JK. Anatomic correlates of aortic pulse wave velocity and carotid artery elasticity during atherosclerosis progression and regression in monkeys. Circulation 1991;83:1754-63. 5) Ichihara A, Hayashi M, Koura Y, Tada Y, Hirota N, Saruta T. Long-term effects of intensive blood-pressure lowering on arterial wall stiffness in hypertensive patients. Am J Hyper- 1105
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