Tian Hai Koh

The REMEDEE trial: a randomized comparison of a combination sirolimus-eluting endothelial progenitor cell capture stent with a paclitaxel-eluting stent.

OBJECTIVES This study sought to compare the efficacy and safety results after coronary implantation of a combined sirolimus-eluting CD34 antibody coated Combo stent (OrbusNeich Medical, Ft. Lauderdale, Florida) with the paclitaxel-eluting Taxus Liberté stent (PES) (Boston Scientific, Natick, Massachusetts). This report summarizes the first-in-man randomized, controlled multicenter REMEDEE trial (Randomized study to Evaluate the safety and effectiveness of an abluMinal sirolimus coatED bio-Engineered StEnt) angiographic, intravascular ultrasound, and clinical results up to 12 months. BACKGROUND Drug-eluting stents have limited restenosis and reintervention but are complicated by especially late and very late stent thrombosis and accelerated neoatherosclerosis. Alternative or adjunct technologies should address these limitations. METHODS One hundred eighty-three patients with de novo native coronary artery stenoses were randomized 2:1 to Combo stent or PES implantation. The primary endpoint is the angiographic in-stent late lumen loss at 9 months, which was tested for noninferiority between the 2 stent groups. Secondary endpoints include the occurrence of major adverse cardiac events. RESULTS The Combo stent was found to be noninferior to the PES in 9-month angiographic in-stent late lumen loss with 0.39 ± 0.45 mm versus 0.44 ± 0.56 mm (pnoninferiority = 0.0012). At 12 months, the occurrence of major adverse cardiac events was 8.9% in the Combo group and 10.2% in the PES group (p = 0.80) with no difference in mortality, occurrence of myocardial infarction, or target lesion revascularization. No stent thrombosis was reported in either group. CONCLUSIONS In the REMEDEE trial the Combo stent has shown to be effective by meeting the primary noninferiority angiographic endpoint and safe, with an overall low rate of clinical events in both stent groups, including no stent thrombosis up to 12 months.

Percutaneous transcatheter heart valve implantation in a bicuspid aortic valve.

A 77-year-old man presented with increasingly symptomatic severe aortic stenosis (AS). Echocardiogram showed an aortic valve area of 0.6 cm2 and a mean pressure gradient of 57 mm Hg. It could not be ascertained conclusively if the valve was tricuspid or bicuspid due to heavy calcification ([Figs. 1

Percutaneous mitral valve repair with the MitraClip: early results from the MitraClip Asia-Pacific Registry (MARS).

AIMS Percutaneous MitraClip therapy has been shown to be safe and efficacious in mitral regurgitation (MR). Our aim was to describe early outcomes in patients from the Asia- Pacific region. METHODS AND RESULTS The MitraClip Asia-Pacific Registry (MARS) includes data from eight different centres in five countries in the Asia-Pacific region. The primary efficacy outcome was reduction in MR to ≤2+ at 30 days. The safety outcome was 30-day freedom from major adverse events (MAE), defined as the composite of death, myocardial infarction, non-elective cardiac surgery, renal failure, transfusion of ≥2 units of blood, ventilation for >48 hours, septicaemia, and new onset atrial fibrillation. A total of 142 patients underwent the MitraClip procedure from February 2011 to October 2013. Fifty-three point five percent (76) of patients had functional MR, 45.8% (65) had degenerative MR and 0.7% (1) had mixed MR. The acute procedural success rate was 93.7% (133). Thirty-one point seven percent of the patients were in NYHA Class I-II at baseline, compared to 82.1% at 30 days (p<0.001). Zero percent (0) of the patients had ≤2+ MR at baseline compared to 76.8% (109) at 30 days (p<0.001). CONCLUSIONS Results from the Asia-Pacific region show that the MitraClip procedure is effective in reducing mitral regurgitation and has favourable short-term safety outcomes.

Recalibration of the Global Registry of Acute Coronary Events risk score in a multiethnic Asian population

BACKGROUND Acute myocardial infarction (AMI) is a leading cause of mortality in Asia. However, quantitative risk scores to predict mortality after AMI were developed without the participation of Asian countries. METHODS We evaluated the performance of the Global Registry of Acute Coronary Events (GRACE) in-hospital mortality risk score, directly and after recalibration, in a large Singaporean cohort representing 3 major Asian ethnicities. RESULTS The GRACE cohort included 11,389 patients, predominantly of European descent, hospitalized for AMI or unstable angina from 2002 to 2003. The Singapore cohort included 10,100 Chinese, 3,005 Malay, and 2,046 Indian patients hospitalized for AMI from 2002 to 2005.Using the original GRACE score, predicted in-hospital mortality was 2.4% (Chinese), 2.0% (Malay), and 1.6% (Indian). However, observed in-hospital mortality was much greater at 9.8% (Chinese), 7.6% (Malay), and 6.4% (Indian). The c statistic for Chinese, Malays, and Indians was 0.86, 0.86, and 0.84, respectively, and the Hosmer-Lemeshow statistic was 250, 56, and 41, respectively. Recalibration of the GRACE score, using the mean-centered constants derived from the Singapore cohort, did not change the c statistic but substantially improved the Hosmer-Lemeshow statistic to 90, 24, and 18, respectively. The recalibrated GRACE score predicted in-hospital mortality as follows: 7.7% (Chinese), 6.0% (Malay), and 5.2% (Indian). CONCLUSION In this large cohort of 3 major Asian ethnicities, the original GRACE score, derived from populations outside Asia, underestimated in-hospital mortality after AMI. Recalibration improved risk estimation substantially and may help adapt externally developed risk scores for local practice.

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.

Differences in late cardiovascular mortality following acute myocardial infarction in three major Asian ethnic groups

Aim: the purpose of this study was to investigate differences in long-term mortality following acute myocardial infarction (AMI) in patients from three major ethnicities of Asia. Methods and results: We studied 15,151 patients hospitalized for AMI with a median follow-up of 7.3 years (maximum 12 years) in six publicly-funded hospitals in Singapore from 2000–2005. Overall and cause-specific cardiovascular (CV) mortality until 2012 were compared among three major ethnic groups that represent large parts of Asia: Chinese, Malay and Indian. Relative survival of all three ethnic groups was compared with a contemporaneous background reference population using the relative survival ratio (RSR) method. The median global registry of acute coronary events score was highest among Chinese, followed by Malay and Indians: 144 (25th percentile 119, 75th percentile 173), 138 (115, 167), and 131 (109, 160), respectively, p<0.0001; similarly, in-hospital mortality was highest among Chinese (9.8%) followed by Malay (7.6%) and Indian (6.4%) patients. In contrast, 12-year overall and cause-specific CV mortality was highest among Malay (46.2 and 32.0%) followed by Chinese (43.0 and 27.0%) and Indian (35.9 and 25.2%) patients, p<0.0001. The five-year RSR was lowest among Malay (RSR 0.69) followed by Chinese (RSR 0.73) and Indian (RSR 0.79) patients, compared with a background reference population (RSR 1.00). Conclusions: We observed strong inter-Asian ethnic disparities in long-term mortality after AMI. Malay patients had the most discordant relationship between baseline risk and long-term mortality. Intensified interventions targeting Malay patients as a high-risk group are necessary to reduce disparities in long-term outcomes.

Circadian Dependence of Infarct Size and Acute Heart Failure in ST Elevation Myocardial Infarction

Objectives There are conflicting data on the relationship between the time of symptom onset during the 24-hour cycle (circadian dependence) and infarct size in ST-elevation myocardial infarction (STEMI). Moreover, the impact of this circadian pattern of infarct size on clinical outcomes is unknown. We sought to study the circadian dependence of infarct size and its impact on clinical outcomes in STEMI. Methods We studied 6,710 consecutive patients hospitalized for STEMI from 2006 to 2009 in a tropical climate with non-varying day-night cycles. We categorized the time of symptom onset into four 6-hour intervals: midnight–6:00 A.M., 6:00 A.M.–noon, noon–6:00 P.M. and 6:00 P.M.–midnight. We used peak creatine kinase as a surrogate marker of infarct size. Results Midnight–6:00 A.M patients had the highest prevalence of diabetes mellitus (P = 0.03), more commonly presented with anterior MI (P = 0.03) and received percutaneous coronary intervention less frequently, as compared with other time intervals (P = 0.03). Adjusted mean peak creatine kinase was highest among midnight–6:00 A.M. patients and lowest among 6:00 A.M.–noon patients (2,590.8±2,839.1 IU/L and 2,336.3±2,386.6 IU/L, respectively, P = 0.04). Midnight–6:00 A.M patients were at greatest risk of acute heart failure (P<0.001), 30-day mortality (P = 0.03) and 1-year mortality (P = 0.03), while the converse was observed in 6:00 A.M.–noon patients. After adjusting for diabetes, infarct location and performance of percutaneous coronary intervention, circadian variations in acute heart failure incidence remained strongly significant (P = 0.001). Conclusion We observed a circadian peak and nadir in infarct size during STEMI onset from midnight–6:00A.M and 6:00A.M.–noon respectively. The peak and nadir incidence of acute heart failure paralleled this circadian pattern. Differences in diabetes prevalence, infarct location and mechanical reperfusion may account partly for the observed circadian pattern of infarct size and acute heart failure.

Critical path in cardiac stem cell therapy: an update on cell delivery.

Despite optimal medical therapy, cardiovascular disease remains a leading cause of morbidity and mortality worldwide. One emerging therapeutic approach for treatment of cardiomyopathies is stem cell therapy. Use of stem cells for regenerative medicine has quickly evolved over the last decade. On the basis of encouraging pre-clinical results, stem cell therapy has developed rapidly into a potentially promising treatment for ischemic heart disease, myocardial infarction and congestive heart failure. In this review, we summarize the current state-of-the-art of stem cell therapy and compare collective experiences gleaned from trials using intravenous, intra-coronary and intra-myocardial delivery in exacting credible benefits. We discuss implications of clinical outcomes reported in relation to the delivered stem cells as probable destiny therapy for cardiovascular repair.

Thrombin generation and fibrinolytic activities among patients receiving reduced-dose alteplase plus abciximab or undergoing direct angioplasty plus abciximab for acute myocardial infarction

The purpose of this study was to determine the impact of these 2 reperfusion strategies (reduced-dose alteplase plus abciximab or direct angioplasty plus abciximab) on fibrinolytic and thrombin generation activities. The effect of reduced-dose alteplase plus abciximab and direct angioplasty plus abciximab on hemostatic factors is unknown. Of 70 patients with acute myocardial infarction of < or = 6 hours, 34 were randomized to reduced-dose alteplase (35 to 50 mg in 1 hour) and 36 to direct angioplasty. A standard bolus and infusion dose of abciximab was administered to all patients. Blood specimens were collected at baseline, and at 1, 4, 12, and 24 hours. The following parameters were assayed: fibrinogen, plasminogen and antiplasmin activities, tissue plasminogen activator antigen, D-dimer, prothrombin fragments F1 + 2, and thrombin/antithrombin III complexes. Among patients treated with reduced-dose alteplase plus abciximab, the fibrinogen level decreased by 28.4% in the first hour (11.7 +/- 3.4 vs 7.8 +/- 2.5 micromol/L, p <0.001). Correspondingly, plasminogen and antiplasmin activities decreased by 43.8% (p <0.001) and 59.1% (p <0.001), respectively. Prothrombin fragments F1 + 2 increased from 2.2 +/- 1.7 to 4.2 +/- 1.6 nmol/L (1 hour) (p <0.001) and thrombin/antithrombin III increased from 16.3 +/- 15.0 to 33.5 +/- 19.9 microg/L (1 hour) (p <0.001). Conversely, in the direct angioplasty group, there was a marginal elevation in fibrinogen level at 1 hour (10.2 +/- 2.4 vs 10.6 +/- 2.0 micromol/L, p = 0.064) despite a significant reduction in plasminogen and an increase in tissue plasminogen activator levels. There was no significant change in prothrombin fragments F1 + 2 and thrombin/antithrombin III levels. Thus, there was considerable fibrinolytic activity with reduced-dose alteplase plus abciximab; thrombin generation was not prevented. Among patients treated with direct angioplasty, there was some endogenous fibrinolytic activity, but there was no significant thrombin generation.

Comparison of novel 6.5 Fr sheathless guiding catheters versus 5 Fr guiding catheters for transradial coronary intervention.

AIMS To assess the safety and efficacy of a novel sheathless (SH) 6.5 Fr (French) hydrophilic-coated guiding catheter (GC) compared to the standard 5 Fr GCs in transradial coronary interventions (TRI). METHODS AND RESULTS Patients undergoing TRI with 6.5 Fr SH or 5 Fr GCs were included. Baseline characteristics and in-hospital outcomes were recorded. Primary endpoints were procedural success and presence of radial pulse at discharge. Secondary endpoints were successful GC support, in-hospital adverse events, access-site complications, procedural duration and contrast load. There were 269 patients with 146 procedures in each group. The SH GC group had more non-ST elevation MI, in-stent restenosis, high-risk and bifurcation lesions. Procedural success in both arms was 95.2%. One patient in each group (0.7%) experienced radial artery occlusion (RAO) after TRI, without clinical sequelae. One access-site haematoma and one minor stroke occurred in the 5 Fr group (none in the SH group, both p=ns). Mean procedure time (52±21 vs. 45±21 minutes, p=0.004) and contrast load (160±45 ml vs. 140±45 ml, p=0.003) were greater in the SH group. CONCLUSIONS Both 6.5 Fr SH GCs and 5 Fr GCs achieved high procedural TRI success with low RAO rates. The SH GC eliminated the disadvantages of the 5 Fr GC whilst maintaining the advantage of low RAO rates, and may become the GC of choice in TRI.