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Chi-Hang Lee,
Bee-Choo Tai,
Chao-Yang Soon,
Adrian F Low,
Kian-Keong Poh,
Tiong-Cheng Yeo,
Gek-Hsiang Lim,
James Yip, Abdul Razakjr Omar,
Swee-Guan Teo,
Huay-Cheem Tan
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ABSTRACT: We sought to determine the intravascular ultrasound-derived anatomic criteria for functionally significant lesions in small coronary arteries with a reference segment diameter <3 mm. A fractional flow reserve (FFR) of <0.75, as determined by pressure wire using high-dose (100 to 150 microg) intracoronary adenosine, was used as the reference standard for functional significance. For the 94 patients/lesions involved in the present study, the average reference vessel diameter was 2.72 mm. The FFR was <0.75 in 38 patients (40.4%) and > or =0.75 in 56 patients (59.6%). Logistic regression analysis identified the minimal lumen area, plaque burden, and lesion length as the 3 most important determinants of the FFR. Using classification and regression tree analysis, the best cutoff values for these determinants to discriminate a FFR of <0.75 versus > or =0.75 were a minimal lumen area of < or =2.0 mm(2) (sensitivity 82.35%, specificity 80.77%), plaque burden of > or =80% (sensitivity 87.9%, specificity 78.9%), and lesion length of > or =20 mm (sensitivity 63.6%, specificity 78.9%). A significant increase was found in the area under the receiver operating characteristic curve of the combined parameters (minimal lumen area plus plaque burden plus lesion length) compared to the plaque burden (p = 0.014) and other individual parameters (p <0.001). In conclusion, we found that intravascular ultrasound-derived anatomic criteria are able to predict the functional significance of intermediate lesions in small coronary arteries. A minimal lumen area of < or =2.0 mm(2), plaque burden of > or =80%, and lesion length of > or =20 mm predicted a FFR of <0.75 with good sensitivity and specificity.
The American journal of cardiology 05/2010; 105(10):1378-84. · 3.58 Impact Factor
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Ming-He Huang,
Vincent Nguyen,
Yewen Wu,
Saurabh Rastogi,
Charles Y Lui,
Yochai Birnbaum,
Hui-Qun Wang,
David L Ware,
Madhu Chauhan,
Nisha Garg,
Kian-Keong Poh,
Lei Ye, Abdul Razakjr Omar,
Huay-Cheem Tan,
Barry F Uretsky,
Kenichi Fujise
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ABSTRACT: The purpose of this study was to determine whether intrinsic cardiac adrenergic (ICA) cells release calcitonin gene-related peptide (CGRP), exerting synergistic adrenopeptidergic cardioprotection.
In situ hybridization coupled with immunostaining demonstrated that ICA cells exclusively expressed CGRP mRNA and co-expressed CGRP and delta-opioid receptor in human and rat left ventricular (LV) myocardium. Radioimmunoassay detected constitutive CGRP release from ICA cells in human and rat hearts. The delta-opioid agonist [D-Pen(25)]-enkephalin (DPDPE) increased CGRP release from ICA cells in denervated rat heart. In an ischaemia/reperfusion rat model, pre-ischaemic treatment with DPDPE reduced infarct size (IS) by 51 +/- 16% (P < 0.01). Co-infusion of beta(2)-adrenergic receptor (beta(2)-AR) and CGRP receptor (CGRP-R) antagonists increased IS by 62 +/- 23% (P < 0.01) compared with saline and abolished DPDPE-initiated IS reduction. Pre-treatment of ICA cell-myocyte co-culture with the beta(2)-AR/CGRP-R antagonists increased myocyte death rate by 24 +/- 4% (P < 0.01) and abolished DPDPE-initiated myocyte protection against hypoxia/reoxygenation (re-O(2)). In the ICA cell-depleted myocyte culture, DPDPE did not confer myocyte protection. Supplementing ICA cell-depleted myocyte culture with beta(2)-AR/CGRP-R agonists reduced hypoxia/re-O(2)-induced myocyte death by 24 +/- 5% (P < 0.01), simulating endogenous neurohormonal effects of ICA cells. Western blot analysis showed that DPDPE markedly increased phosphorylated myocardial Akt levels. This effect was abolished in the presence of beta(2)-AR/CGRP-R blockade. Terminal dUTP nick-end labelling staining analysis of the LV infarct zone demonstrated that DPDPE reduced myocyte apoptosis by 58 +/- 19% (P < 0.05), an effect that was eliminated in the presence of beta(2)-AR/CGRP-R blockade. Finally, echocardiography showed that DPDPE increased LV contractility in a manner dependent on beta-AR/CGRP-R stimulation.
ICA cells constitute a delta-opioid-regulated adrenopeptidergic paracrine system conferring robust cardioprotection through beta(2)-AR/CGRP-R co-signalling, resulting in the activation of an anti-apoptotic pathway during ischaemia/reperfusion.
Cardiovascular research 08/2009; 84(3):452-60. · 5.80 Impact Factor
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ABSTRACT: Atherosclerotic coronary artery thrombosis is the most common cause of acute myocardial infarction.
A 30-year-old lady presented with acute peripartum massive anterior ST segment myocardial infarction and cardiogenic shock. This was due to acute Stanford type A aortic dissection with the intimal flap occluding the left coronary ostium. The initial diagnosis was not apparent. Echocardiography confirmed the diagnosis.
She underwent emergency surgical repair (Bentall procedure). Pathology confirmed underlying idiopathic cystic medial degeneration.
A high index of clinical suspicion is required in acute myocardial infarction presenting without traditional cardiovascular risk factors.
Annals of the Academy of Medicine, Singapore 11/2007; 36(10):854-6. · 1.25 Impact Factor
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ABSTRACT: Digital storage of echocardiographic data offers logistical advantages over videotape archival. However, limited information is available on the accuracy of clinically compressed digitised examinations, an important consideration for patient safety.
Transthoracic echocardiograms of 520 consecutive patients were prospectively acquired digitally and on videotape. Two echocardiologists, in consensus, reported studies in both formats sequentially. Using the videotape as a reference, the significance of any reported differences was graded from both imaging and clinical standpoints, and the reasons for these differences identified.
From an imaging perspective, differences between digital and videotaped studies were absent or minor in 459 cases (88%), fairly significant in 55 (11%) and very significant in 6 (1%). The main reasons for the observed differences were inadequate acquisition of optimal views (59%), an insufficient number of acquired cardiac cycles (25%) and suboptimal image quality (9%). These differences were considered to be of possible or definite clinical importance in 21 (4%) and 8 (2%) cases, respectively. In multinominal logistic regression models, the only independent predictor of significant difference between digitised and videotaped images was study complexity. Regardless of case complexity, most diagnostic errors arising from digital review were attributable to technical failure rather than observer error.
The potential for important errors arising from exclusive reporting of clinically compressed digital echocardiograms is small. Digital echocardiography, as practiced in a routine clinical setting, offers a patient-safe alternative to videotape review.
Annals of the Academy of Medicine, Singapore 09/2007; 36(8):662-71. · 1.25 Impact Factor
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Journal of Cardiovascular Electrophysiology 11/2006; 17(10):1150-2. · 3.06 Impact Factor
