• Clinical and Experimental Pediatrics
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• v.46 no.1
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• pp.67-75
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• 2003

Purpose : Intravascular stent implantation for the treatment of postoperative branch pulmonary artery(PA) stenosis has been used successfully. However, the cross sectional area of contralateral branch PA does not regress in spite of the successful dilation of the stenotic branch PA after stent implantation. We analyzed the morphologic and hemodynamic factors on the size of branch PA after successful stent implantation. Methods : The subjects in our study were 23 children who had undergone stent implantaion from Jan. 1995 to Jul. 2002 in the Division of Yonsei Pediatric Cardiology. We evaluated the cross sectional area index(CSAI) of branch PA before and after stent implantation at follow-up catheterization. We also investigated factors such as residual pulmonary stenosis, pulmonary regurgitation(PR), systolic pressure of right ventricle, and lung perfusion scan. Results : The CSAI of the RPA without stenosis changed from mean $238{\pm}17mm^2/BSA$ to mean $249{\pm}20mm^2/BSA$(P=0.47), but didn't regress. The CSAI of the LPA with stenosis was increased effectively by stent implantation from the mean $102{\pm}12mm^2/BSA$ to mean $125{\pm}11mm^2/BSA$(P< 0.05). At follow up after stent implantation, the CSAI of PA is correlated with the residual PR fraction after stent implantation. Conclusion : In a group with increased residual PR, CSAI of RPA was found to be significantly increased between the pre- and post-stages of stent implantation. So, we suspect that the pulmonary regurgitation remaining after right ventricle outlet tract(RVOT) dilatation surgery is correlated with the increase in CSAI of RPA.

• The Korean Journal of Nuclear Medicine
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• v.39 no.4
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• pp.224-230
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• 2005

Purpose: The maximal elastance ($E_{max}$) of myocardium has been established as a reliable load-independent contractility index. Recently, we developed a noninvasive method to measure the regional contractility using gated myocardial SPECT and arterial tonometry data. In this study, we measured regional $E_{max}(rE_{max}$ in the patients who underwent coronary artery bypass graft surgery (CABG), and assessed its relationship with other variables. Materials and Methods: 21 patients (M:F=17:4, $58{\pm}12$ y) who underwent CABG were enrolled. $^{201}TI$ rest/dipyridamole stress $^{99m}Tc$-sestamibi gated SPECT were performed before and 3 months after CABG. For 15 myocardial regions, regional time-elastance curve was obtained using the pressure data of tonometry and the volume data of gated SPECT. To investigate the coupling with myocardial function, preoperative regional $E_{max}$ was compared with regional perfusion and systolic thickening. In addition, the correlation between $E_{max}$ and viability was assessed in dysfunctional segments (thickening <20% before CABG). The viability was defined as improvement of postoperative systolic thickening more than 10%. Results: Regional $E_{max}$ was slightly increased after CABG from $2.41{\pm}1.64 (pre)\;to\;2.78{\pm}1.83 (post)$ mmHg/ml. $E_{max}$ had weak correlation with perfusion and thickening (r=0.35, p<0.001). In the regions of preserved perfusion (${\geq}60%$), $E_{max}$ was $2.65{\pm}1.67$, while it was $1.30{\pm}1.24$ in the segments of decreased perfusion. With regard to thickening, $E_{max}$ was $3.01{\pm}1.92$ mmHg/ml for normal regions (thickening ${geq}40%$), $2.40{\pm}1.19$ mmHg/ml for mildly dysfunctional regions (<40% and ${\geq}20%$), and $1.13{\pm}0.89$ mmHg/ml for severely dysfunctional regions (<20%). $E_{max}$ was improved after CABG in both the viable (from $1.27{\pm}1.07\;to\;1.79{\pm}1.48$ mmHg/ml) and non-viable segments (from $0.97 {\pm}0.59\;to\;1.22{\pm}0.71$ mmHg/ml), but there was no correlation between $E_{max}$ and thickening improvements (r=0.007). Conclusions: Preoperative regional $E_{max}$ was relatively concordant with regional perfusion and systolic thickening on gated myocardial SPECT. In dysfunctional but viable segments, $E_{max}$ was improved after CABG, but showed no correlation with thickening improvement. As a load-independent contractility index of dysfunctional myocardial segments, we suggest that the regional $E_{max}$ could be an independent parameter in the assessment of myocardial function.