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Articles by B. H Oh
Total Records ( 4 ) for B. H Oh
  J. Y Kim , H. J Cho , J. J Sir , B. K Kim , J Hur , S. W Youn , H. M Yang , S. I Jun , K. W Park , S. J Hwang , Y. W Kwon , H. Y Lee , H. J Kang , B. H Oh , Y. B Park and H. S. Kim
  Aims

Inflammation, and the subsequent proliferative activity of vascular smooth muscle cells (VSMCs), is one of the major pathophysiological mechanisms associated with neointimal hyperplasia following vascular injury. Although sulfasalazine (SSZ) has been used as an anti-inflammatory and immune-modulatory agent in various inflammatory diseases, its primary targets and therapeutic effects on vascular disease have not yet been determined. We investigated whether SSZ could suppress VSMC growth and prevent neointimal hyperplasia.

Methods and results

SSZ was found to have pro-apoptotic and anti-proliferative activity in cultured VSMCs. Unexpectedly, these effects were not mediated by nuclear factor kappa B (NF-B) inhibition, which has been suggested to be the anti-inflammatory mechanism associated with the effects of SSZ. Instead, cell-cycle arrest of the VSMCs was observed, which was mediated by induction of haem oxygenase-1 (HO-1) followed by an increased expression of p21waf1/Cip1. The underlying mechanism for SSZ-induced HO-1 expression was by reactive oxygen species (ROS)-dependent nuclear translocation and activation of nuclear factor erythroid-2-related factor 2 (Nrf2). In a rat carotid artery balloon injury model, administration of SSZ significantly suppressed neointimal growth. In a series of reverse experiments, inhibition of HO-1 by shRNA, ROS by N-acetylcysteine (NAC) or Nrf2 by dominant-negative Nrf2 abrogated the beneficial effects of SSZ.

Conclusion

Our data demonstrate that SSZ inhibits VSMC proliferation in vitro and in vivo through a novel signalling pathway and may be a promising therapeutic option for the treatment of proliferative vascular disease.

  Y. J Kim , D. A Kwon , J. S Park , S Hahn , K. H Kim , K. B Kim , D. W Sohn , H Ahn , B. H Oh and Y. B. Park
 

Background— We sought to identify preoperative predictors of clinical outcomes after surgery in patients with severe tricuspid regurgitation.

Methods and Results— We prospectively enrolled 61 consecutive patients (54 women, aged 57±9 years) with isolated severe tricuspid regurgitation undergoing corrective surgery. Twenty-one patients (34%) were in New York Heart Association functional class II, 35 (57%) in class III, and 5 (9%) in class IV. Fifty-seven patients (93%) had previous history of left-sided valve surgery. Preoperative echocardiography revealed pulmonary artery systolic pressure of 41.5±8.7 mm Hg, right ventricular (RV) end-diastolic area of 35.1±9.0 cm2, and RV fractional area change of 41.3±8.4%. The median follow-up duration after surgery was 32 months (range, 12 to 70). Six of the 61 patients died before discharge; thus, operative mortality was 10%. Three of the 55 patients who survived surgery died during follow-up, and 6 patients required readmission because of cardiovascular problems. Thus, 46 patients (75%) remained event free at the end of follow-up. In the 54 patients who underwent 6-month clinical and echocardiographic follow-up, RV end-diastolic area decreased by 29%, with a corresponding 26% reduction in RV fractional area change. Thirty-three patients (61%) showed improved functional capacity after surgery. On multivariable Cox regression analysis, preoperative hemoglobin level (P<0.001) and RV end-systolic area (P<0.001) emerged as independent determinants of clinical outcomes. On receiver operating characteristic curve analysis, we found that RV end-systolic area <20 cm2 predicted event-free survival with a sensitivity of 73% and a specificity of 67%, and a hemoglobin level >11.3 g/dL predicted event-free survival with a sensitivity of 73% and a specificity of 83%.

Conclusions— Timely correction of severe tricuspid regurgitation carries an acceptable risk and improves functional capacity. Surgery should be considered before the development of advanced RV systolic dysfunction and before the development of anemia.

  H. E Park , S. A Chang , H. K Kim , D. H Shin , J. H Kim , M. K Seo , Y. J Kim , G. Y Cho , D. W Sohn , B. H Oh and Y. B. Park
 

Background— The effects of left ventricular (LV) loading conditions on LV dyssynchrony have not been elucidated. We modified LV loading conditions to reveal their effects on echocardiography-derived LV dyssynchrony index (LVdys) in patients with documented nonischemic dilated cardiomyopathy.

Methods and Results— Thirty-seven patients were consecutively enrolled. After baseline measurements, pneumatic compression of the lower extremities (Pcom) was used to increase LV afterload. Subsequently, sublingual nitroglycerin (SL-NG) was administered to modify preload. Conventional echocardiographic parameters, LVdys (by speckle-tracking radial strain analysis) and LV end-systolic wall stress (LV-ESWS), were calculated under each condition. LVdys-6 (defined as the maximal difference in time-to-peak radial strain between 6 myocardial segments) and LV-ESWS increased under Pcom (for LVdys-6, 159±117 at baseline versus 239±140 ms under Pcom, P<0.05; for LV-ESWS, 191±63 versus 228±80 g/m2, P<0.05) After SL-NG application, both parameters decreased significantly (for LVdys-6, 239±140 under Pcom versus 147±103 ms after SL-NG, P<0.05; for LV-ESWS, 228±80 under Pcom versus 189±67 g/m2 after SL-NG, P<0.05). When the presence of LV dyssynchrony was defined as the absolute difference in time-to-peak radial strain between the anteroseptal and posterior segments (LVdys-2), the results were unchanged. Using 130 ms as a cutoff value, the proportion of patients with LV dyssynchrony changed significantly (29.7% at baseline, 45.9% under Pcom, and 35.1% after SL-NG). When the presence of LV dyssynchrony was defined as standard deviation of the time to peak radial strain for 6 segments (LVdys-SD), the results were same. LVdys and LV-ESWS showed a modest but significant association with each other (r=0.47, P<0.001 for LVdys-6; r=0.41, P<0.001 for LVdys-2; r=0.46, P<0.001 for LVdys-SD).

Conclusions— To the best of our knowledge, the present study provides the first evidence of a significant association between LVdys and LV loading status, reflective of a dynamic nature of LVdys. Accordingly, LV loading conditions should be taken into account when echocardiographic LVdys is used for clinical decision-making of selecting candidates for cardiac resynchronization therapy or when it is used as a surrogate marker of prognosis.

  J. W Chung , H. M Yang , K. W Park , H. Y Lee , J. S Park , H. J Kang , Y. S Cho , T. J Youn , B. K Koo , I. H Chae , D. J Choi , B. H Oh , Y. B Park and H. S. Kim
  Background—

In the COREA-TAXUS trial ("Effect of Celecoxib On REstenosis after coronary Angioplasty with a TAXUS stent"), celecoxib reduced late luminal loss and adverse cardiac events at follow-up around 6 months. The objective of this study was to assess the long-term outcome of short-term adjunctive celecoxib treatment after paclitaxel-eluting stent implantation.

Methods and Results—

This is a 2-year clinical follow-up of the COREA-TAXUS trial, an open-label randomized controlled study. A total 274 patients were randomized to receive or not receive celecoxib (400 mg before the intervention and 200 mg twice daily for 6 months after the procedure), and 271 underwent successful paclitaxel-eluting stent implantation. All patients were given aspirin (100 mg daily indefinitely) and clopidogrel (75 mg daily for at least 6 months). Among the 271 patients, 267 (98.5%) completed the 2-year clinical follow-up. From the previous follow-up to 2 years, there was no difference in the rate of adverse cardiac events between the celecoxib and control groups (1.6% versus 4.3%, P=0.27). Thus, at 2 years, the rate of adverse cardiac events was consistently lower in the celecoxib group (6.9% versus 19.7%, P=0.002). A significant reduction in need for target lesion revascularization was observed (6.2% versus 18.2%, P=0.003). The efficacy benefit in the celecoxib group was not undermined by an increased risk for cardiac death or myocardial infarction at 2 years (1.5% versus 1.4%).

Conclusions—

Six-month adjunctive celecoxib treatment after paclitaxel-eluting stent implantation was associated with durable long-term efficacy up to 2 years. However, the inconclusive evidence for the long-term safety of this treatment warrants caution.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov. Unique identifier: NCT 00292721.

 
 
 
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