대동맥 판막질환환자에게서 혈역학적 특징 및 관상동맥 혈류 양상과의 관계 : 혈관내 Doppler Wire를 이용한 연구

고종훈,김한수,탁승제,김동진,신준한,최병일 대한순환기학회 1998 Korean Circulation Journal Vol.28 No.10

관상동맥 조영술상 정상인 고혈압환자에서 관상동맥 혈류 예비력의 결정인자

고종훈,윤명호,최소연,탁승제 관동대학교 의과대학 의과학연구소 2005 關東醫大學術誌 Vol.9 No.1

Background ; Several studies were reported that reduction of coronary flow reserve(CFR) might lead to myocardial ischemia in the absence of epicardial coronary stenosis. In addition left ventricular hypertrophy might be associated with impairment of coronary flow reserve. The aim of the this study was to assess whether relation exists between CFR and left ventricular mass index(LVMI) and to evaluate the major determinant factors of CFR. Method ; We studied 32 inpatients with hypertension and normal coronary angiogram. Control group consised of 19 subjects(M:F=10:9, mean age 52.6±9.7), group Ⅰ included 14 subjects (LVMI is below 125mg/m2,M:F=6.8 mean age 55.3±14.6) and group Ⅱ consist of 18 subject (LVMI is exceeded 125mg/m2,M:F=5:13 mean age 55.8±9.4). We measured the left ventricular mass(LVM) by M-mode echocardiogram using Devereus and Reichek's method. Left ventricular mass index was calculated as LVM / BSA. We measured average peak velocity at baseline(B) and at adenosine induced hyperemie(H) at the proximal segment of left anteriror descending artery(LAD) using a 0.014 inch 15MHZ doppler wire, CFR was calculated as the hyperemic/baseline(H/B) average peak velocity ratio. Result : 1) There was no significant difference In heart rate, systolic blood pressure or diastolic blood pressure between the two hypertensive groups. 2) The B-APV was significantly increased in hypertensive group compared to the control group(14.4±4.7./21.7.±7.5/23.1±8.1cm/sec p<0.05). 3) CFR was significant reduced in groupⅠand groupⅡ than in the control group (3.2±0.4/2.53±0.6/2.38±0.7 p<0.05). Conclusion ; In hypertensive patients with angiographicaly normal coronary arteries, coronary flow reserve was significantly reduced than normal control group. and CFR was mainly determinant by baseline average peak velocity and not by left ventricular mass index.

THE INFLUENCES OF SWIRL FLOW ON FRACTIONAL FLOW RESERVE IN MILD/MODERATE/SEVERE STENOTIC CORONARY ARTERIAL MODELS

이경은,김국태,류아진,심은보 한국전산유체공학회 2017 한국전산유체공학회지 Vol.22 No.1

Swirl flow is often found in proximal coronary arteries, because the aortic valves can induce swirl flows in the coronary artery due to vortex formation. In addition, the curvature and tortuosity of arterial configurations can also produce swirl flows. The present study was performed to investigate fractional flow reserve alterations in a post-stenotic distal part due to the presence of pre-stenotic swirl flow by computational fluid dynamics analysis for virtual stenotic models by quantifying fractional flow reserve(FFR). Simplified stenotic coronary models were divided into those with and without pre-stenotic swirl flow. Various degrees of virtual stenosis were grouped into three grades: mild, moderate, and severe, with degree of stenosis of 0 ~ 40%, 50 ~ 60%, and 70 ~ 90%, respectively. In this study, three-dimensional computational hemodynamic simulations were performed under hyperemic conditions in virtual stenotic coronary models by coupling with a zero-dimensional lumped parameter model. The results showed that the influence of pre-stenotic swirl inflow is dominant on FFR alteration in mild stenosis, whereas stenosis is dominant on FFR alteration in moderate/severe stenosis. The decrease in FFR caused by swirl flow is more significant in mild stenosis than moderate/severe stenosis. Biomechanical modeling is useful for clinicians to provide insight for medical intervention strategies. This hemodynamic-based parameter study could play a critical role in the development of a non-invasive imaging-based strategy-support system for percutaneous transluminal angioplasty in cases of mild/moderate stenosis.

THE INFLUENCES OF SWIRL FLOW ON FRACTIONAL FLOW RESERVE IN MILD/MODERATE/SEVERE STENOTIC CORONARY ARTERIAL MODELS

Kyung Eun Lee(이경은),Gook Tae Kim(김국태),Ah-Jin Ryu(류아진),Eun Bo Shim(심은보) 한국전산유체공학회 2017 한국전산유체공학회지 Vol.22 No.1

Swirl flow is often found in proximal coronary arteries, because the aortic valves can induce swirl flows in the coronary artery due to vortex formation. In addition, the curvature and tortuosity of arterial configurations can also produce swirl flows. The present study was performed to investigate fractional flow reserve alterations in a post-stenotic distal part due to the presence of pre-stenotic swirl flow by computational fluid dynamics analysis for virtual stenotic models by quantifying fractional flow reserve(FFR). Simplified stenotic coronary models were divided into those with and without pre-stenotic swirl flow. Various degrees of virtual stenosis were grouped into three grades: mild, moderate, and severe, with degree of stenosis of 0 ~ 40%, 50 ~ 60%, and 70 ~ 90%, respectively. In this study, three-dimensional computational hemodynamic simulations were performed under hyperemic conditions in virtual stenotic coronary models by coupling with a zero-dimensional lumped parameter model. The results showed that the influence of pre-stenotic swirl inflow is dominant on FFR alteration in mild stenosis, whereas stenosis is dominant on FFR alteration in moderate/severe stenosis. The decrease in FFR caused by swirl flow is more significant in mild stenosis than moderate/severe stenosis. Biomechanical modeling is useful for clinicians to provide insight for medical intervention strategies. This hemodynamic-based parameter study could play a critical role in the development of a non-invasive imaging-based strategy-support system for percutaneous transluminal angioplasty in cases of mild/moderate stenosis.

Association between fractional flow reserve and coronary plaque characteristics assessed by optical coherence tomography

Lee,, S.Y.,Shin, D.H.,Shehata, I.,Kim, J.S.,Kim, B.K.,Ko, Y.G.,Choi, D.,Jang, Y.,Hong, M.K. Japanese College of Cardiology 2016 Journal of cardiology Vol.68 No.4

<P>Background: The assessment of fractional flow reserve (FFR) in coronary lesions determines the strategy of percutaneous coronary intervention. However, the association between FFR and characteristics of the underlying coronary plaque has not been sufficiently investigated. Methods: A total of 110 coronary lesions in 106 patients were evaluated using both FFR and optical coherence tomography (OCT). Coronary plaques were classified into fibrous, fibrocalcific, or fibroatheroma according to 00' evaluation at the site of minimal lumen area. Plaque microstructures such as cap thickness, macrophage accumulation, intimal vasculature, or cholesterol crystals were also evaluated. Results: Lesions with FFR <= 0.8 showed a higher frequency of fibroatheroma, macrophage accumulation, and cholesterol crystals when compared to those with FFR > 0.8. The angle of lipid was wider in lesions with FFR <= 0.8 (145.1 +/- 63.0 degrees vs. 120.7 +/- 48.9 degrees, p = 0.047), and the longitudinal length was longer in those with FFR <= 0.8 (4.2 +/- 2.8 mm vs. 2.5 +/- 2.9 mm, p = 0.007). However, multiple linear regression analysis revealed that the morphological characteristics of plaques assessed by OCT were not independently associated with FFR. Minimal lumen area [coefficient, 0.035; 95% confidence interval (CI), 0.022-0.048; p < 0.001] and area stenosis (coefficient, -0.003; 95% CI, 0.005 to -0.001; p = 0.001) assessed by OCT significantly correlated with FFR. Conclusion: The morphological characteristics of coronary plaque derived from OCT are not directly related to FFR. (C) 2015 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.</P>

고혈압 치료에 의한 허혈성 심질환 예방

김병옥 대한고혈압학회 1996 대한고혈압학회지 Vol.2 No.1

Fractional Flow Reserve: The Past, Present and Future

김정은,구본권 대한심장학회 2012 Korean Circulation Journal Vol.42 No.7

Revascularization of coronary artery stenosis should be based on the objective evidence of ischemia. It is common practice for physicians to make decisions on revascularization in the cardiac catheterization laboratory based on the results of angiography, despite the fact that angiographic information does not correlate well with the functional significance of a coronary lesion. Fractional flow reserve (FFR) is a physiologic parameter which can be measured easily during the invasive procedure and can assess the functional significance of coronary stenosis. FFR-guided revascularization strategy is reported to be more effective than angiography-guided strategy in patients with coro-nary artery disease. Moreover, novel technologies based on FFR have been developed and will soon be incorporated into clinical practic.

The Relationship between Microcirculatory Resistance and Fractional Flow Reserve in Patients with Acute Myocardial Infarction

오준혁,차광수,안지희,김진희,양미진,이혜원,최정현,이한철,홍택종,김창훈 대한심장학회 2013 Korean Circulation Journal Vol.43 No.8

Background and Objectives: It was demonstrated that the fractional flow reserve (FFR) with partial balloon obstruction may have impli-cations for assessing viable myocardium. In a different way, the index of microcirculatory resistance (IMR) was introduced as a useful in-dicator for assessing microvascular function. We evaluated the relationship between the FFR 0.8 and the IMR. Subjects and Methods: We studied 48 consecutive patients who had undergone coronary intervention for acute myocardial infarction (AMI). After revascularization using stent(s), an undersized short balloon was positioned inside the stent and inflated to create a specific normalized pressure drop of FFR (distal coronary/aortic pressure=0.80) at rest. The FFR 0.8 was obtained during hyperemia with the fixed state balloon-induced partial obstruction. IMR was measured by three injections of saline. The association between the FFR 0.8 and the IMR was investigated. Results: The mean age of the patients was 60±12 years and 36 (75%) overall presented with ST-segment elevation myocardial infarc-tion. The mean FFR 0.8 was 0.68±0.06. A statistically significant correlation between the FFR 0.8 and the log-transformed IMR true (LnIMR true )was found through a multivariable linear regression analysis (β=0.056, p<0.001). Both the FFR 0.8 and the LnIMR true had a positive correla-tion with the log-transformed peak troponin I (TnI) with statistical significance (r 2 =0.119, p=0.017; r 2 =0.225, p=0.006, respectively). Conclusion: There was a positive correlation between the LnIMR true and the FFR 0.8 . Both of the values were associated with peak TnI. Those values may be used as appropriate surrogate measures of microvascular function after AMI.

경흉부 심초음파를 이용한 관동맥 혈류속도 예비력에 의한 경피적 관동맥 성형술후 재협착의 비침습적인 진단

임세중,고영국,강석민,하종원,최동훈,장양수,정남식 대한심장학회 2008 Korean Circulation Journal Vol.38 No.6

Background and Objectives: Coronary flow reserve (CFR) decreases in the presence of significant coronary stenosis. Hence, CFR can be used for the detection of restenosis after percutaneous coronary intervention (PCI). However, because CFR can also be affected by other conditions such as endothelial dysfunction, microvascular damage, and left ventricular hypertrophy, the absolute value of CFR is not routinely used for detection of coronary restenosis. We hypothesized that changes in the value of CFR, rather than the absolute CFR value, are better correlated with restenosis in various clinical settings. Subjects and Methods: We studied 99 patients (71 males/28 females, mean age 58±11 years) who underwent successful PCI of the left anterior descending artery. Pre-PCI diagnoses were as follows: 37 unstable angina, 35 stable angina, 27 acute myocardial infarction. CFR using transthoracic Doppler was measured at 48 hours after PCI and at the time of follow-up angiography (6.0±1.5 months later). Coronary flow velocity was measured in the distal left anterior descending artery with a 7 MHz transducer (HDI 5,000, Philips, The Netherlands) at baseline and during intravenous infusion of adenosine (140 μg·kg-1·min-1). Mean diastolic coronary flow velocities from at least three cardiac cycles were averaged. Results: CFRs in 69 patients without restenosis were 2.55±0.99 at 48 hours after PCI and 2.93±1.00 at follow-up (p<0.005). CFRs in 30 patients with restenosis (>50% in diameter stenosis) decreased significantly from 2.70± 1.01 at 48 hours after PCI to 1.98±0.91 at follow-up (p<0.001). There was a significant difference in CFR change (ratio of CFRfollowup/CFRinitial) between the two groups. CFR change had a better receiver operating characteristics (ROC) curve than absolute CFR for prediction of restenosis [area under the curve (AUC) for absolute CFR= 0.76, AUC for CFR change=0.82]. Conclusion: Restenosis after PCI leads to a significant decrease in CFR, even in the presence of variable baseline CFR values. Serial measurements of CFR can be used to detect restenosis after PCI. Background and Objectives: Coronary flow reserve (CFR) decreases in the presence of significant coronary stenosis. Hence, CFR can be used for the detection of restenosis after percutaneous coronary intervention (PCI). However, because CFR can also be affected by other conditions such as endothelial dysfunction, microvascular damage, and left ventricular hypertrophy, the absolute value of CFR is not routinely used for detection of coronary restenosis. We hypothesized that changes in the value of CFR, rather than the absolute CFR value, are better correlated with restenosis in various clinical settings. Subjects and Methods: We studied 99 patients (71 males/28 females, mean age 58±11 years) who underwent successful PCI of the left anterior descending artery. Pre-PCI diagnoses were as follows: 37 unstable angina, 35 stable angina, 27 acute myocardial infarction. CFR using transthoracic Doppler was measured at 48 hours after PCI and at the time of follow-up angiography (6.0±1.5 months later). Coronary flow velocity was measured in the distal left anterior descending artery with a 7 MHz transducer (HDI 5,000, Philips, The Netherlands) at baseline and during intravenous infusion of adenosine (140 μg·kg-1·min-1). Mean diastolic coronary flow velocities from at least three cardiac cycles were averaged. Results: CFRs in 69 patients without restenosis were 2.55±0.99 at 48 hours after PCI and 2.93±1.00 at follow-up (p<0.005). CFRs in 30 patients with restenosis (>50% in diameter stenosis) decreased significantly from 2.70± 1.01 at 48 hours after PCI to 1.98±0.91 at follow-up (p<0.001). There was a significant difference in CFR change (ratio of CFRfollowup/CFRinitial) between the two groups. CFR change had a better receiver operating characteristics (ROC) curve than absolute CFR for prediction of restenosis [area under the curve (AUC) for absolute CFR= 0.76, AUC for CFR change=0.82]. Conclusion: Restenosis after PCI leads to a significant decrease in CFR, even in the presence of variable baseline CFR values. Serial measurements of CFR can be used to detect restenosis after PCI.

관상동맥 협착 환자에서의 관동맥 혈류 예비능 - Doppler Guidewire Study-

김무현(Moo Hyun Kim),배성진(Sung Jin Bae),양창호(Chang Ho Yang),김상곤(Sang Gon Kim),손지원(Ji Won Son),도현국(Hyun Kuk Dho),김종성(Jong Seong Kim) 대한내과학회 1996 대한내과학회지 Vol.50 No.2

N/A Objectives: Coronary flow reserve(CFR) is the ratio of the maximal hyperemic to basal coronary blood flow velocity hyperemia, which was introduced by Gould et al, as a functional parameter in the coronary artery stenosis. Methods: To evaluate the difference of the CFR between the significant and insignificant coronary artery narrowings, we measured coronary flow velocity in 17 patients(11 nonstenotic group and 6 stenotic patients) by 0.0l4 inch intracoronary Doppler-tipped guidewire after nitroglycerine 200㎍ intracoronary infusion during coronary arteriography. We measured coronary flow velocity in 11 left coronary artery and 6 right coronary artery before and after adenosine intracoronary infusion(LCA 12㎍, RCA 6㎍). Results: 1) Average peak velocity(APV, cm/sec) of steno- tic patients was higher than nonstenotic group(19.8 vs 36.6, p<0.05), but diastolic systolic velocity ratio (DSVR) were not significantly different between both groups. 2) APV after adenosine infusion in stenotic and nonstenotic group were 56.3±16.4, 60±23.4cm/sec, respectively, which are significantly increased compared to the basal state(p<0.01). 3) Mean coronary flow reserve(CFR) in the stenotic group was significantly lower than nonstenotic group(1.98±0.9 vs 3.57±1.0, p<0.01). 4) Systolic and diastolic blood pressure decreased significantly after adenosine intracoronery bolus infusion(p<0.01), but heart rate did not changed significantly(p>0.05). The mean time that came back to the baseline flow velocity after adenosine infusion was 27.1 seconds. Conclusion: Coronary flow reserve decreased significantly in the coronary artery stenosis compared to normal or insignificant stenosis. And adenosine caused significant fall in blood pressure after intracoronary infusion, but did not in heart rate