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Biomedical subjects

Dae-Won Sohn

Publications and source records attributed to Dae-Won Sohn.

33 records · Page 2Linked to original sources
PubMed2004

Effects of intracoronary infusion of peripheral blood stem-cells mobilised with granulocyte-colony stimulating factor on left ventricular systolic function and restenosis after coronary stenting in myocardial infarction: the MAGIC cell randomised clinical trial.

BACKGROUND: Bone-marrow stem-cell transplantation has been shown to improve cardiac function in patients with myocardial infarction. We examined the feasibility and efficacy of granulocyte-colony stimulating factor (G-CSF) therapy and subsequent intracoronary infusion of collected peripheral blood stem-cells (PBSCs) in such patients. METHODS: We prospectively randomised 27 patients with myocardial infarction who underwent coronary stenting for the culprit lesion of infarction into three groups; cell infusion (n=10), G-CSF alone (n=10), and control group (n=7). Changes in left ventricular systolic function and perfusion were assessed after 6 months. By December, 2003, seven patients from the cell infusion group, three from the G-CSF group, and one from the control group had been assessed. FINDINGS: G-CSF injection and intracoronary infusion of the mobilised PBSC did not aggravate inflammation and ischaemia during the periprocedural period. Exercise capacity (mean treadmill exercise time: 450 s [SD 178] at baseline vs 578 s [168] at 6 months' follow-up, p=0.004), myocardial perfusion (perfusion defect 11.6% [9.6] vs 5.3% [5.0], p=0.020) and systolic function (left ventricular ejection fraction 48.7% [8.3] vs 55.1% [7.4], p=0.005) improved significantly in patients who received cell infusion. However, we noted an unexpectedly high rate of in-stent restenosis at culprit lesion in patients who received G-CSF, and therefore we stopped enrollment. INTERPRETATION: G-CSF therapy with intracoronary infusion of PBSC showed improved cardiac function, and promoted angiogenesis in patients with myocardial infarction. However, aggravation of restenosis could be a serious problem. In future studies with G-CSF based stem-cell therapy, patients should be carefully monitored for unexpected effects.

Arteries↗
PubMed2004

Impact of left ventricular diastolic function on exercise capacity in patients with chronic mitral regurgitation: an exercise echocardiography study.

BACKGROUND: Mitral regurgitation (MR) is known as one of the most frequent causes of heart failure and sudden death. In spite of increasing prevalence of MR, there have been no available data on cardiac determinants of exercise capacity in patients with chronic MR. HYPOTHESIS: This study aimed to investigate cardiac determinants of exercise capacity in patients with chronic MR. METHODS: We consecutively enrolled 32 patients (11 men, mean age: 44 +/- 14 years) who had greater than moderate MR with normal left ventricular (LV) systolic function (LV ejection fraction >50%). Conventional echocardiographic indices and parameters measured by Doppler tissue imaging at septal side of mitral annulus were obtained before exercise. Mitral regurgitation fraction, forward stroke volume, pulmonary venous flow velocities, and systolic pulmonary artery pressure (sPAP) were also obtained with standard methods. RESULTS: Left ventricular ejection fraction was 61 +/- 6% and MR fraction was 48 +/- 13%. All patients finished a symptom-limited treadmill exercise test with a peak heart rate of >85% of predicted maximum heart rate. Mean exercise time was 9.95 +/- 2.17 min, corresponding to 11 +/- 2 metabolic equivalents. Among pre-exercise echocardiographic variables, only early diastolic mitral annulus velocity (E') and pulmonary venous reversal flow velocity (PVa) showed a significant correlation with exercise time (r = 0.44, p = 0.011, and r = -0.40, p = 0.040, respectively), which persisted after multivariate analysis (p = 0.011 and 0.038, respectively). Other parameters such as systolic mitral annulus velocity, resting and postexercise sPAP, forward stroke volume, LV size, LV ejection fraction, left atrial size, and regurgitant fraction showed no significant correlation. CONCLUSIONS: Left ventricular diastolic function is an important determinant of exercise capacity in patients with chronic MR. Both E' and PVa, accepted surrogate estimates for LV diastolic function, may be useful for identifying patients with chronic MR and with poor exercise capacity.

Adult↗
PubMed2004

Unique features of early diastolic mitral annulus velocity in constrictive pericarditis.

BACKGROUND: In most primary myocardial diseases, early diastolic mitral annulus velocity (E') decreases with disease progression. To our knowledge, constrictive pericarditis (CP) is the only condition without this phenomenon. OBJECTIVE: This study was performed to evaluate the diagnostic and pathophysiologic role of mitral annulus velocity in patients with CP. METHODS: In all, 17 patients with CP (9 men; mean age 46.5 +/- 14.3 years), 8 patients with cardiac tamponade (Tamp) (2 men; mean age 44.5 +/- 15.0 years), and age- and sex-matched control subjects for CP and Tamp were recruited for the study. Early mitral inflow velocity and E' were obtained while simultaneously recording respiration. In 8 patients with CP and in all patients with Tamp, these measurements were repeated after the relief of constrictive physiology or after pericardiocentesis. RESULTS: In patients with CP, E' was significantly higher than it was for control subjects (12.9 +/- 3.0 cm/s vs 9.8 +/- 2.4 cm/s, P <.01). An E' of 2 cm/s higher than the predicted normal E' could differentiate patients with CP from control subjects with a sensitivity of 76% and specificity of 82%. In 12 of 17 patients (71%), inspiratory E' was higher than expiratory E'-the opposite of mitral inflow variation. In 8 patients, E' decreased significantly after the relief of constrictive physiology (13.8 +/- 2.5 cm/s vs 9.3 +/- 3.1 cm/s, P <.05). In contrast, E' in the Tamp group was significantly lower than in the control group (6.8 +/- 1.6 cm/s vs 10.2 +/- 2.5 cm/s, P <.01), did not show significant respiratory variation, and increased significantly after pericardiocentesis (6.8 +/- 1.6 cm/s vs 9.5 +/- 3.0 cm/s, P <.05). CONCLUSION: E' is exaggerated in CP, which is helpful for diagnosis. The opposite phenomenon was noted in Tamp, a dissimilarity that might contribute to different hemodynamics.

Adult↗
PubMed2004

Transthoracic echocardiographic evaluation of coronary flow reserve in patients with hypertrophic cardiomyopathy.

Recently, it has become possible to measure coronary flow reserve (CFR) non-invasively with transthoracic echocardiography (TTE). Twenty-one hypertrophic cardiomyopathy (HCMP) patients with asymmetric septal hypertrophy who had either not started medication or had stopped medication for at least 24 h were enrolled, along with 29 normal subjects. Mean diastolic coronary flow velocity (CFmv) and time velocity integral of diastolic coronary flow velocity (CFtvi) were measured at the distal left anterior descending artery with a 7 MHz transducer at the baseline and after dipyridamole infusion at a dose of 0.56 mg/kg. CFR was defined as the ratio of CFmv after dipyridamole over CFmv before dipyridamole. The baseline values for CFmv and CFtvi were significantly higher (0.40+/-0.09 vs. 0.31+/-0.06 m/s, p<0.001, 0.25+/-0.07 vs. 0.16+/-0.04 m, p<0.001, respectively), while that for CFR was significantly lower (2.01+/-0.42 vs. 3.06+/-0.39 m/s, p<0.001) in the HCMP patients, compared to the normal subjects. In the HCMP patients, CFR showed a moderate negative correlation with both baseline CFmv (r=-0.522, p=0.015) and baseline CFtvi (r=-0.495, p=0.034). Treadmill test was performed in 14 patients with Bruce protocol. CFR, baseline CFmv and baseline CFtvi did not correlate with maximal exercise time. In seven patients, the CFR measured after verapamil treatment was not significantly different from that measured before treatment. In conclusion, in patients with HCMP, CFR is probably reduced due to the recruitment of vasodilatory capacity at the resting state and this reduction is not directly related to reduced exercise capacity. Also, CFR is not affected by treatment with calcium antagonist.

Adult↗
PubMed2004

Effects of beta-radiation with a 188rhenium-filled balloon catheter system on non-stented adjacent coronary artery segments.

BACKGROUND: The effects of beta-radiation with a (188)rhenium ((188)Re)-filled balloon catheter system on angiographically normal reference segments have not been well defined. METHODS: In the Seoul National University Post-Angioplasty Rhenium irradiation (SPARE) trial, patients with de novo or restenotic lesions were first treated with a conventional catheter-based technique and then randomized to either a radiation group or a control group. Irradiation was performed using a (188)Re-filled conventional balloon catheter system. Among 97 radiation group enrolled in this study from April 1998 through May 2001, 20 patients with de novo lesions who received brachytherapy with a balloon at least 10 mm longer than the length of an implanted stent, were selected and their post-intervention and follow-up intravascular ultrasound (IVUS) images were analyzed. Each reference segment was divided into two segments; full dose-irradiation with injury segment (irradiated segment; from the stent edge to the radiopaque balloon markers), and low dose-irradiation without injury segment (edge segment; 5-mm long segment proximal or distal to the location of radiopaque markers). In control group, serial IVUS analysis was available only in 10 patients, and IVUS parameters of the non-stented adjacent segments in these patients were compared to those of irradiated segments in radiation group patients. RESULTS: Forty irradiated and 38 edge segments of the 20 radiation group patients were analyzed. In proximal irradiated segments, no significant changes were found in external elastic membrane (EEM), lumen or in the plaque plus media (P&M) areas. In distal irradiated segments, significant increases in the EEM (12.5+/-4.5 to 14.0+/-5.0 mm(2), P<0.01) and P&M areas (5.5+/-2.0 to 6.6+/-2.3 mm(2), P<0.01) were found to occur without a change in lumen area. In proximal edge segments, P&M areas were significantly increased (9.0+/-1.7 to 10.5+/-2.6 mm(2), P=0.03). No significant changes in EEM, lumen or P&M areas were observed in the distal edge segments. Comparisons between the irradiated segments (n=40) in the radiation group and the non-stented adjacent segments (n=19) in the control group showed a significant difference in the percentage change of EEM areas (18.5+/-33.2% in radiation group vs. -3.1+/-32.1% in control group, P=0.02). CONCLUSIONS: beta-radiation with a (188)Re-filled conventional balloon catheter system appears to have no significant deleterious effect on angiographically normal reference segments over a 6 months follow up after brachytherapy.

Aged↗
PubMed2004

Association between cardiac valvular calcification and coronary artery disease in a low-risk population.

BACKGROUND: Mitral annulus calcification (MAC) or aortic valve sclerocalcification (AVSC) is common with aging and associated with coronary artery disease (CAD) in Caucasians. This study was performed to determine whether MAC or AVSC is also associated with, and has a power to predict, CAD in Koreans as in Caucasians. METHODS: Three hundred and eight patients with chest pain, who had undergone coronary angiography and transthoracic echocardiography, were enrolled (189 males; mean 60.5 +/- 9.8 years). RESULTS: The prevalence of MAC and AVSC was significantly more common in CAD (+) compared with CAD (-) group (83.9%:55.2%, 87.9%:57.5%, respectively, both p < 0.001). On multivariate analysis with MAC and AVSC along with conventional coronary risk factors (cRF), MAC, male gender, AVSC, and diabetes mellitus were significantly associated with CAD (p < 0.001, < 0.001, 0.010 and 0.014 respectively). Additionally, a positive linear relationship was found between the prevalence of both MAC and AVSC and the extent of CAD defined by the number of stenotic coronary arteries (both p < 0.001). Furthermore, the odds ratio for CAD in the group with both multiple valvular sclerocalcification (MVSC) and > or = 2 cRF was 12.3 compared to the < or = 1 cRF group without MVSC. CONCLUSIONS: MAC and AVSC were independently associated with CAD in a low-risk Korean population. Also, combination of MVSC with > or = 2 cRF increased the predictability of the presence of CAD. Therefore, the possibilities of CAD must be considered when MVSC is detected in transthoracic echocardiography in patients with > or = 2 cRF.

Aged↗
PubMed2004

Three-year clinical follow-up results of intracoronary radiation therapy using a rhenium-188-diethylene-triamine-penta-acetic-acid-filled balloon system.

BACKGROUND: Intracoronary radiation therapy (IRT) prevents recurrent in-stent restenosis, but its long-term safety and efficacy remain uncertain. In the present study, the long-term clinical outcome of IRT using the rhenium-188 ((188)Re)-filled balloon system was evaluated. METHODS AND RESULTS: After successful catheter-based treatment of either a de novo or restenotic lesion, 187 patients were randomly assigned to either the radiation (N=104) or the control (N=83) group. The (188)Re-filled balloon system was designed to deliver 17.6 Gy to 1.0-mm tissue depth. Angiographic restenosis was significantly reduced with IRT at 9 months (18.9% vs 45.9%, p<0.001), but the incidence of major adverse cardiac events (MACE) including death, myocardial infarction, and target-vessel revascularization (TVR) by 3 years showed no difference. Lack of clinical benefit might be related to TVR caused by geographic miss (6/22, 28.6%), balloon-induced unhealed dissection (3/22, 13.6%) and late thrombosis (2/22, 9.1%). In the restenotic subgroup (N=39), the MACE rate within 3 years was significantly reduced with IRT (14.3% vs 54.5%, p=0.01). CONCLUSIONS: IRT using the (188)Re -filled balloon system is safe and technically feasible. Although IRT failed to show favorable outcomes for de novo lesion, the clinical benefits for restenotic lesions seem durable for 3 years. Furthermore, preventing geographic miss and dissection might improve long-term outcomes.

Aged↗
PubMed2003

Determinants of exercise capacity in hypertensive patients: new insights from tissue Doppler echocardiography.

BACKGROUND: Determinants of exercise capacity have not been clearly defined in hypertensive patients. Doppler tissue imaging (DTI), a recently developed echocardiographic modality, is useful for evaluating left ventricular (LV) function regardless of loading conditions. The present study was performed to identify the determinants of exercise capacity in hypertensive patients using DTI. METHODS: We studied 48 hypertensive patients (26 men; mean age, 57 +/- 9 years) with normal LV ejection fraction (>50%). Conventional echocardiographic indexes were measured before and after symptom-limited treadmill exercise. Also, longitudinal systolic (S(L)') and diastolic myocardial velocities (E(L)' and A(L)') and radial velocities (S(R)', E(R)', A(R)') were measured using DTI with the sample volume at the LV basal posterior wall. RESULTS: Mean exercise time was 525 +/- 135 sec. Mean LV ejection fraction was 61% +/- 6%. Mean LV mass index was 110.9 +/- 24.4 g/m(2). On univariate analysis, S(L)', E(L)', A(L)' and percentage increase of S(R)' velocity after exercise showed significant correlation with exercise time. However, only E(L)' and percentage increase of S(R)' remained significant after multivariate analysis. CONCLUSIONS: Left ventricular contractile reserve and relaxation property are important cardiac factors determining exercise capacity. Early diastolic longitudinal myocardial velocity might be useful for identifying hypertensive patients with poor exercise capacity.

Adult↗
PubMed2003

Mechanism and incidence of notched pulmonary venous atrial reversal wave.

In certain patients, pulmonary venous flow pattern obtained by the pulsed wave Doppler during transesophageal echocardiography shows a notching on the atrial reversal (A) wave. However, the incidence or the mechanism of this notched A wave has not been described. After transthoracic echocardiographic evaluation for the chamber sizes, wall thickness, and left-ventricular function, transesophageal echocardiography was performed in 100 patients with in sinus rhythm. Discernible pulmonary venous A wave was observed in 46 patients. Among these 46 patients, notched A wave was observed in 11 (31%). In 4 patients with notched A wave, left-atrial pressure waveforms could be obtained during mitral balloon valvuloplasty. In all these patients, left-atrial pressure waveforms showed prominent c waves. In 2 patients, transesophageal echocardiography was repeated after mitral balloon valvuloplasty. Late peak of the notched A wave decreased with the decrease in the magnitude of rise in left-atrial c wave. Among the transthoracic echocardiographic parameters, patients with notching (n = 11) had significantly larger left atriums than patients without notching (n = 35)(49.3 +/- 6.2 vs 37.3 +/- 4.4 mm, P <.0001). There were no significant differences in left-ventricular dimensions, wall thickness, and ejection fraction. In conclusion, notched pulmonary venous A wave indicates the presence of left-atrial c wave; and presence of left-atrial c wave may represent decreased left-atrial compliance.

Adult↗
PubMed2003

Prediction of postoperative left ventricular systolic function with Doppler-derived dP/dt in patients with chronic aortic regurgitation.

To evaluate the value of Doppler-derived dP/dt as a predictor of postoperative left ventricular (LV) systolic function in patients with chronic aortic regurgitation, we evaluated 29 patients who underwent aortic valve replacement (n = 17) or valve repair. Doppler-derived dP/dt was determined from the continuous wave Doppler signal of the aortic regurgitation jet preoperatively. Preoperative LV ejection fraction (LVEF) and Doppler-derived dP/dt were 48 +/- 11% and 701 +/- 204 mm Hg/s, respectively. LVEF decreased to 43 +/- 12% at immediate postoperative period and improved to 54 +/- 11% at late postoperative period. In multivariate analysis, only dP/dt was an independent predictor of late postoperative LVEF (r = 0.59, P =.006). A dP/dt <or=700 mm Hg/s was the best predictor of late postoperative systolic dysfunction (LVEF <50%) with a sensitivity of 94% and a specificity of 75%. Doppler-derived dP/dt may be useful to predict postoperative LV systolic function.

Adult↗
PubMed2003

Differential diagnosis of slow/slow atrioventricular nodal reentrant tachycardia from atrioventricular reentrant tachycardia using concealed posteroseptal accessory pathway by 12-lead electrocardiography.

Slow pathways are used as both antegrade and retrograde conduction pathway in slow/slow atrioventricular nodal reentrant tachycardia (SS-AVNRT), and patients with SS-AVNRT have tachycardia ECGs mimicking atrioventricular reentrant tachycardia using concealed posteroseptal accessory pathway (PS-AVRT). Therefore, SS-AVNRT can be misdiagnosed as PS-AVRT, and the differential diagnosis is clinically important. Standard 12-lead ECGs during tachycardia were analyzed in patients with SS-AVNRT (n = 10) and PS-AVRT (n = 10). All these patients were diagnosed by electrophysiological study and underwent successful catheter ablation. Differences of the RP' intervals (dRP') between V1 and the inferior leads were evaluated. SS-AVNRT had significantly longer RP' intervals measured in V1 (167 +/- 25.2 vs 137 +/- 26.8 ms, SS-AVNRT vs PS-AVRT, respectively, P = 0.02), longer dRP' between V1 and II (dRP'[V1-II], 37 +/- 14 vs 17 +/- 6.7 ms, P = 0.0007), longer dRP'[V1-III] (39 +/- 14 vs 17 +/- 9.9 ms, P = 0.0011), and longer dRP'[V1-aVF] (39 +/- 13 vs 20 +/- 9.5 ms, P = 0.0008). The following criteria were suggested for differential diagnosis of SS-AVNRT from PS-AVRT: dRP'[V1-II] >25 ms (sensitivity and specificity: 80% and 100%, respectively), dRP'[V1-III] >23 ms (90% and 90%), dRP'[V1-aVF] >30 ms (90% and 90%). Differences of the RP' intervals between V1 and the inferior leads in the tachycardia ECGs were useful for differential diagnosis of SS-AVNRT from PS-AVRT.

Adult↗
PubMed2002

Absence of postprandial surge in coronary blood flow distal to significant stenosis: a possible mechanism of postprandial angina.

OBJECTIVES: This study was designed to investigate a possible mechanism of postprandial angina. BACKGROUND: Postprandial angina has been recognized for more than two centuries; however, its mechanism is still controversial. The most widely accepted mechanism involves increased myocardial oxygen demand after food intake. Recently, the redistribution in coronary blood flow (CBF) was suggested as a possible mechanism. METHODS: Twenty young, healthy volunteer controls and 20 patients with significant stenosis in the left anterior descending (LAD) or left main coronary artery were enrolled in the study. Coronary blood flow was evaluated in the distal LAD by using transthoracic Doppler echocardiography before and 15, 30, 45, and 60 min after food intake. In the CBF curve, the time velocity integral of diastolic flow (Dtvi) and the product of Dtvi and heart rate (HR) were measured. In six patients, these measurements were repeated after successful coronary intervention. RESULTS: In the healthy volunteer controls, Dtvi and Dtvi x HR increased after food intake with a peak value at 15 min, which indicates the presence of postprandial surge in the CBF. Fasting values and peak values at 15 min were significantly different (Dtvi: 15.1 +/- 4.9 cm/s vs. 18.9 +/- 5.9 cm/s, p = 0.04, Dtvi x HR: 862.2 +/- 261.5 cm/min vs. 1,174.2 +/- 307.5, p = 0.002). In contrast with the controls, despite postprandial increase in double product (HR x blood pressure), Dtvi and Dtvi x HR in the patient group decreased after food intake, with a nadir value at 45 min. Fasting values and nadir values at 45 min were significantly different (Dtvi: 24.0 +/- 19.6 cm/s vs. 19.3 +/- 17.1 cm/s, p < 0.001, Dtvi x HR: 1,449.6 +/- 1,044.0 cm/min vs. 1,273.4 +/- 1,000.9 cm/min, p = 0.002). In six patients, the CBF pattern resumed the normal pattern of postprandial surge in the CBF after successful coronary intervention. CONCLUSIONS: Results of our study suggest that "steal phenomenon" may play a role in the mechanism of postprandial angina.

Adult↗
PubMed2002

Outcomes of medically treated patients with aortic intramural hematoma.

PURPOSE: Aortic intramural hematoma has been considered a precursor of aortic dissection, and the same treatment strategy, usually involving surgery, has been applied to both conditions. However, the outcomes of patients with aortic intramural hematoma who are treated medically, including the remodeling process that occurs after an acute event, are not known. SUBJECT AND METHODS: A total of 124 patients with acute aortic intramural hematoma (41 in the proximal aorta and 83 in the distal aorta) was enrolled from five institutions in South Korea. Patients received medical treatment without surgery. A follow-up imaging study was performed in 105 patients. RESULTS: Pericardial (59% [n = 24] vs. 11% [n = 9], P <0.004) and pleural effusions (63% [n = 26] vs. 45% [n = 37], P = 0.05) were more common in patients with the proximal type than in those with the distal type. In-hospital mortality was somewhat higher with proximal hematomas (7% [n = 3 deaths] vs. 1% [n = 1 death], P = 0.11). A follow-up imaging study in 36 patients with proximal hematomas confirmed resorption of the hematoma in 24 patients (67%) and development of aortic dissection in 9 (25%). Resorption was confirmed in 54 (78%) of the 69 patients with distal hematomas who underwent follow-up imaging; localized aortic dissection developed in 11 (16%) of these patients. The 3-year survival rate was 78% in the proximal type and 87% in the distal type (P = 0.10). CONCLUSION: Patients with aortic intramural hematoma had a high rate of resorption with medical treatment regardless of the affected site. Further investigation is necessary to determine the optimal treatment strategy and timing of surgical intervention, especially for patients with proximal hematomas.

Acute Disease↗