Yean-Teng Lim

Usefulness of ST elevation II/III ratio and ST deviation in lead I for identifying the culprit artery in inferior wall acute myocardial infarction.

In a study of 92 patients presenting with inferior wall acute myocardial infarction, the infarct-related artery was the right coronary artery in 72 patients (78%) and the left circumflex artery in 20 (22%). An ST II/III ratio of 1 or an isoelectric ST in lead I are sensitive and specific markers of left circumflex artery occlusion, whereas an ST II/III ratio <1 (ST elevation in lead III >II) or ST depression in lead I are sensitive and specific markers of right coronary artery occlusion.

Transplantation of Nanoparticle Transfected Skeletal Myoblasts Overexpressing Vascular Endothelial Growth Factor-165 for Cardiac Repair

Background— We investigated the feasibility and efficacy of polyethylenimine (PEI) based human vascular endothelial growth factor-165 (hVEGF165) gene transfer into human skeletal myoblasts (HSM) for cell based delivery to the infarcted myocardium. Methods and Results— Based on optimized transfection procedure using enhanced green fluorescent protein (pEGFP), HSM were transfected with plasmid-hVEGF165 (phVEGF165) carried by PEI (PEI- phVEGF165) nanoparticles. The transfected HSM were characterized for transfection and expression of hVEGF165 in vitro and transplanted into rat heart model of acute myocardial infarction (AMI): group-1=DMEM injection, group-2= HSM transplantation, group-3= PEI-phVEGF165–transfected HSM (PEI-phVEGF165 myoblast) transplantation. A total of 48 rats received cyclosporine injection from 3 days before and until 4 weeks after cell transplantation. Echocardiography was performed to assess the heart function. Animals were sacrificed for molecular and histological studies on the heart tissue at 4 weeks after treatment. Based on optimized transfection conditions, transfected HSM expressed hVEGF165 for 18 days with >90% cell viability in vitro. Apoptotic index was reduced in group-2 and group-3 as compared with group-1. Blood vessel density (×400) by immunostaining for PECAM-1 in group-3 was significantly higher (P=0.043 for both) as compared with group-1 and group-2 at 4 weeks. Regional blood flow (ml/min/g) in the left ventricular anterior wall was higher in group-3 (P=0.043 for both) as compared with group-1 and group-2. Improved ejection fraction was achieved in group-3 (58.44±4.92%) as compared with group-1 (P=0.004). Conclusion— PEI nanoparticle mediated hVEGF165 gene transfer into HSM is feasible and safe. It may serve as a novel and efficient alternative for angiomyogenesis in cardiac repair.

Endothelial progenitor cell capture stent implantation in patients with ST-segment elevation acute myocardial infarction: one year follow-up

AIMS The Genous endothelial progenitor cell (EPC) capture stent is a bioengineered R stent coated with immobilised antibodies on its stent struts to allow for the capture of circulating EPCs to promote rapid endothelisation. We assessed the impact of this stent in the primary percutaneous coronary intervention (PCI) of patients with acute ST-elevation myocardial infarction (STEMI) and examined its long term clinical outcomes. METHODS AND RESULTS All patients with acute STEMI without cardiogenic shock who underwent primary PCI between January 2005 and April 2007 and received the stent were enrolled in the study. The study endpoints were major adverse cardiac events (MACE) defined as death, MI and target vessel revascularisation (TVR) at 30 days, six months and one year. A total of 321 enrolled patients received 357 EPC capture stents during the study period. The cohort comprises 81.0% males with mean age of 54.6+/-11.6 years. The mean stent length used was 20.98+/-5.50 mm and mean stent size was 2.99+/-0.32 mm. Ninety-four percent of patients achieved Thrombolysis in Myocardial Infarction (TIMI) 3 flow post-procedurally. The cumulative MACE rate was 8.1% at 30 days, 10.0% at six months and 12.2% at one year. There was one patient who developed acute stent thrombosis and another two with subacute stent thromboses. No late thrombosis or late cardiac mortality was observed in our cohort. The need for TVR was 4.4% at one year. CONCLUSIONS The use of EPC capture stents in patients who underwent primary PCI for STEMI is safe and showed good clinical outcomes, with low rates of TVR and no late stent thrombosis.

Effectiveness and Safety of the Genous Endothelial Progenitor Cell-Capture Stent in Acute ST-Elevation Myocardial Infarction

The endothelial progenitor cell (EPC)-capture stent promotes endothelialization and preliminary studies have suggested its safety and feasibility in ST-elevation myocardial infarction (STEMI). Detailed late clinical follow-up and angiographic analyses are, however, limited. We sought to determine late angiographic and clinical outcomes of the Genous EPC-capture stent in primary angioplasty. EPC-capture stents were implanted during primary angioplasty in 489 consecutive patients presenting with STEMI from 2004 through 2008. The first 100 consenting patients undergoing successful stent implantation scheduled to undergo relook coronary angiography at 6 to 12 months were enrolled. Ninety-five patients with 96 lesions were analyzed independently. Mean duration of follow-up coronary angiography was 245 days. In-stent late luminal loss measured 0.87 ± 0.67 mm. Binary restenosis (defined as >50% diameter stenosis) was 28%, with diffuse in-stent restenosis (Mehran class II) as the predominant pattern. Of 27 patients with binary restenosis, 14 (52%) were symptomatic, with 10 patients undergoing target lesion revascularization. Asymptomatic patients had significantly larger reference vessel and in-stent minimal luminal diameters (2.77 ± 0.39 vs 2.54 ± 0.44 mm, p = 0.040; 2.74 ± 0.34 vs 2.31 ± 0.72 mm, p = 0.004, respectively). Follow-up late loss and diameter stenoses were also in favor of the asymptomatic group. Major adverse cardiac event rate was 16% at a mean follow-up of 34 months. There were no cases of Academic Research Consortium-defined stent thrombosis. In conclusion, implantation of the EPC-capture stent during primary angioplasty is associated with a favorable late clinical outcome but with higher than anticipated angiographic late loss.

Clinical Experience of StarClose Vascular Closure Device in Patients with First and Recurrent Femoral Punctures

OBJECTIVE We present our clinical experience of StarClose in patients undergoing coronary interventions, including its use in patients after repeated puncture of the same femoral access site. BACKGROUND The StarClose is a novel vascular closure device that deploys a small, flexible, circumferential nitinol clip onto the femoral artery surface. METHODS In this study, 103 consecutive patients (24% with repeated punctures) who underwent percutaneous coronary intervention and received a StarClose were followed up prospectively. The patients were assessed for vascular complications prior to hospital discharge. Device success, based on time-to-hemostasis, was divided into (1) immediate success: hemostasis achieved immediately after StarClose deployment without the need for adjunctive manual compression, (2) partial success: occurrence of minor oozing after StarClose deployment and hemostasis achieved after <3 minutes of manual compression, and (3) device failure: need for adjunctive manual compression for >3 minutes. RESULTS Immediate success, partial success, and device failure rates were 74% (n = 68), 16% (n = 15), and 10% (n = 9), respectively. There were no major complications attributable to the StarClose device. There were 10 (9.7%) cases of minor complications; all were recurrent wound bleeding requiring manual compression in the wards. Among these 10 cases of recurrent bleeding, 5 (50%) had initial device success (immediate success, n = 2, partial success, n = 3) in the catheterization laboratory. The risk for recurrent bleeding was 2.9% after immediate device success and 20.0% after partial device success. CONCLUSION Our study found no major complications but a 10% failure rate and a 9.7% rate of minor complications. Close surveillance is important as there is a risk for recurrent bleeding, especially in patients with partial device success as defined in this report.

Combined fibrinolysis using reduced-dose alteplase plus abciximab with immediate rescue angioplasty versus primary angioplasty with adjunct use of abciximab for the treatment of acute myocardial infarction: Asia-Pacific Acute Myocardial Infarction Trial (APAMIT) pilot study.

We conducted a randomized feasibility pilot study comparing combined fibrinolysis with immediate rescue angioplasty vs. primary angioplasty with adjunctive abciximab in patients with acute myocardial infarction (AMI). Seventy patients with ST segment elevation AMI of ≤ 6 hr were randomized to either 50 mg of alteplase and abciximab (n = 34) or primary angioplasty with adjunctive abciximab (n = 36). Coronary angiography was performed at 60 min in the combined lytic group and TIMI 3 flow was present in 65% of patients as compared to 25% (P = 0.001) in the primary angioplasty group prior to intervention. Treatment success, defined as TIMI 3 flow, was achieved in 83% of patients in the primary angioplasty group (P = 0.075 compared to 65% in combined lytic group before rescue angioplasty). There was no difference in overall treatment success between primary angioplasty and combined lytic group with rescue angioplasty (83% vs. 94%; P = NS). Major adverse cardiac events at 1 month were not significant (15% vs. 11%; P = NS), but there was a trend toward more events in the combined lytic group at 6 months (32% vs. 14%; P = 0.066), particularly in target vessel revascularization. In this feasibility pilot study, high rate of TIMI 3 flow was attained in patients with AMI with both combined fibrinolysis and primary angioplasty with adjunctive abciximab. A larger randomized trial is currently ongoing to compare these two strategies. Cathet Cardiovasc Intervent 2004;62:445–452.

Bridge Over Troubling Spasm: Is the Association of Myocardial Bridging and Coronary Artery Spasm a Distinct Entity? Three Case Reports

The association of coronary artery spasm and myocardial bridging is very uncommon and may represent a distinct clinical entity. Three patients are described, presenting with acute coronary syndrome associated with myocardial bridging and coronary artery spasm. The relationship and respective roles of myocardial bridging and spasm, however, remain uncertain and may be consequent to a direct effect on endothelial function from the compressive effect of myocardial bridging. The role of intracoronary nitroglycerin in these patients is unresolved.

Liposome-based vascular endothelial growth factor-165 transfection with skeletal myoblast for treatment of ischaemic limb disease

The study aims to use cholesterol (Chol) + DOTAP liposome (CD liposome) based human vascular endothelial growth factor‐165 (VEGF165) gene transfer into skeletal myoblasts (SkMs) for treatment of acute hind limb ischaemia in a rabbit model. The feasibility and efficacy of CD liposome mediated gene transfer with rabbit SkMs were characterized using plasmid carrying enhanced green fluorescent protein (pEGFP) and assessed by flow cytometry. After optimization, SkMs were transfected with CD lipoplexes carrying plasmid‐VEGF165 (CD‐pVEGF165) and transplanted into rabbit ischaemic limb. Animals were randomized to receive intramuscular injection of Medium199 (M199; group 1), non‐transfected SkM (group 2) or CD‐pVEGF165 transfected SkM (group 3). Flow cytometry revealed that up to 16% rabbit SkMs were successfully transfected with pEGFP. Based on the optimized transfection condition, transfected rabbit SkM expressed VEGF165 up to day 18 with peak at day 2. SkMs were observed in all cell‐transplanted groups, as visualized with 6‐diamidino‐2‐phenylindole and bromodeoxyuridine. Angiographic blood vessel score revealed increased collateral vessel development in group 3 (39.7 ± 2.0) compared with group 2 (21.6 ± 1.1%, P < 0.001) and group 1 (16.9 ± 1.1%, P < 0.001). Immunostaining for CD31 showed significantly increased capillary density in group 3 (14.88 ± 0.9) compared with group 2 (8.5 ± 0.49, P < 0.001) and group 1 (5.69 ± 0.3, P < 0.001). Improved blood flow (ml/min./g) was achieved in animal group 3 (0.173 ± 0.04) as compared with animal group 2 (0.122 ± 0.016; P= 0.047) and group 1 (0.062 ± 0.012; P < 0.001). In conclusion, CD liposome mediated VEGF165 gene transfer with SkMs effectively induced neovascularization in the ischaemic hind limb and may serve as a safe and new therapeutic modality for the repair of acute ischaemic limb disease.

Surgery for left main spasm. Is it indicated

A 38-year-old Chinese man presented with chest pain associated with loss of consciousness and a witnessed generalized seizure. An electrocardiogram (ECG) done soon after the seizure showed a junctional rhythm and anteroseptal ST elevation of 2 mm with marked inferolateral ST depression of 3 mm. Peak creatinine kinase (CK) was 870 U/l with an MB fraction of 43 U/l. Exercise treadmill test was abnormal with 3 mm inferolateral ST depression at peak exercise. A computed tomographic scan of the head and electroencephalogram were normal. Coronary angiography showed 75% narrowing of the left main coronary artery with normal left anterior descending and circumflex coronary arteries. There was ventricularization of the pressure tracing and the patient experienced chest pain with ST segment depression in leads II and Vl which were the monitoring leads. The blood pressure, however, remained normal. The luminal narrowing increased to 90% (Fig. 1) following the second injection of contrast. Buccal nitroglycerine spray was administered with good symptomatic relief, and reinjection

Long-term safety and efficacy are observed after implantation of Zotarolimus-Eluting stent in real-world clinical practice.

AIMS Zotarolimus-eluting stents (ZESs) have been shown to be safe and effective in randomised trials. We sought to report the clinical outcomes after implantation of ZES in real-world clinical practice. METHODS AND RESULTS ZES have been approved for clinical use in Singapore since April 2005. Until December 31, 2007, a total of 219 patients had undergone implantation of ZES. After excluding 11 foreign patients with whom contact was lost, 208 patients (246 lesions, 305 stents) formed the study cohort. A high-proportion of diabetic patients (n=90, 43.3%) was included. Recommended dual antiplatelet therapy was at least 3 months (n=147) for patients treated before or 12 months (n=61) after January 2007. As of January 2008, the median follow-up duration was 19 months (range: 1 to 33 months). There were 10 (4.8%) deaths, including 7 (3.4%) cardiac deaths. Myocardial infarction occurred in 11 (5.3%) patients. The numbers of patients requiring target vessel revascularisation and target lesion revascularisation were 10 (4.8%) and 5 (2.4%) respectively. Using the ARC definition, there were two cases of definite stent thrombosis on days 7 and 17, and one case of probable stent thrombosis on day 15. CONCLUSIONS In this real-world clinical experience, ZES was associated with a low incidence of adverse cardiac events at a medium follow-up of one and half years.