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Koon-Hou Mak

Publications and source records attributed to Koon-Hou Mak.

17 recordsLinked to original sources
PubMed2005

A global view of atherothrombosis: baseline characteristics in the Clopidogrel for High Atherothrombotic Risk and Ischemic Stabilization, Management, and Avoidance (CHARISMA) trial.

BACKGROUND: The manifestations of atherothrombosis such as myocardial infarction, ischemic stroke, limb ischemia, or cardiovascular death pose a global health care burden. Additional therapies to decrease ischemic events in patients with established vascular disease or at risk for developing vascular disease are necessary. We sought to characterize the risk factors and treatments of a diverse contemporary population of patients with atherothrombosis. METHODS: The CHARISMA trial has enrolled 15,603 patients from around the world. Patients with established coronary, cerebrovascular, or peripheral arterial disease, or those at high risk of developing atherothrombosis due to multiple risk factors, have been randomized to receive either the adenosine diphosphate receptor antagonist clopidogrel or placebo, in addition to background therapy with low- to moderate-dose aspirin. RESULTS: A high percentage of enrolled patients are being treated with statins and angiotensin-converting enzyme inhibitors. In the CHARISMA population, a total of 75.6% of the population had an abnormal body mass index: 42.2% were overweight and 33.4% were obese, with particularly high rates in the United States, especially of morbid obesity. Correspondingly, the prevalence of diabetes was 42%. CONCLUSION: The CHARISMA trial will further characterize atherothrombosis and provide insight into the role of dual antiplatelet therapy in improving outcomes in patients with multiple risk factors or established vascular disease. Of note, the rates of obesity and diabetes in patients with atherothrombosis throughout the world are particularly alarming.

Adult↗
PubMed2004

Six-month outcomes after single- and multi-lesion percutaneous coronary intervention: results from the ROSETTA registry.

BACKGROUND: The American College of Cardiology/American Heart Association exercise testing guidelines suggest that routine functional testing may benefit patients at high risk of restenosis, such as those undergoing multi-lesion percutaneous coronary intervention (PCI). OBJECTIVES: To compare the six-month post-PCI clinical and procedural outcomes in patients following single- and multi-lesion PCI, and to examine the use of routine functional testing (ie, in all patients) versus selective functional testing (ie, only in those with recurrent symptoms) following multi-lesion PCI. METHODS: Six-month outcomes among 562 patients after single-lesion PCI and 229 patients after multi-lesion PCI were examined. All patients were enrolled in the Routine versus Selective Exercise Treadmill Testing after Angioplasty (ROSETTA) registry, a prospective, multicentre registry examining the use of functional testing after successful PCI. RESULTS: For single- versus multi-lesion PCI patients, respectively, rates of death (1.8% versus 2.2%, P=0.7) and myocardial infarction (0.7% versus 2.6%, P=0.03) were low in both groups. Rates of unstable angina (12.0% versus 11.7%, P=0.9) and the composite clinical end point of death, myocardial infarction or unstable angina (13.5% versus 13.9%, P=0.9) were similar. Multi-lesion PCI patients had a higher number of repeat PCI procedures (6.6% versus 13.4%, P=0.02) but there was no difference in the rates of coronary artery bypass graft surgery (3.0% versus 2.6%, P=0.7). A routine functional testing strategy was used in 28.0% of single-lesion and 31.6% of multi-lesion patients. In a multivariate analysis of the multi-lesion patients, routine functional testing was not associated with a significant reduction in the composite clinical event rate (odds ratio 0.5, 95% CI 0.2 to 1.7, P=0.27). CONCLUSIONS: During the six-month period following successful PCI, clinical event rates were similar among patients undergoing single- or multi-lesion PCI. Routine functional testing was not associated with a statistically significant benefit in patients after multi-lesion PCI. However, additional study is required to better define the role of routine functional testing in this subgroup of patients.

Angina, Unstable↗
PubMed2004

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.

Abciximab↗
PubMed2004

Ethnic differences in utilization of invasive cardiac procedures and in long-term survival following acute myocardial infarction.

BACKGROUND: Ethnic differences in coronary mortality have been documented, and South Asians from the Indian subcontinent are particularly vulnerable. HYPOTHESIS: This study sought to determine whether there was a difference in the utilization of invasive cardiac procedures and long-term mortality in survivors of myocardial infarction (MI) among Chinese, Malays, and South Asians in Singapore. METHODS: All MI events in the country were identified and defined by the Singapore Myocardial Infarction Register, which uses modified procedures of the World Health Organization MONICA Project. Information on utilization of coronary angiography, coronary angioplasty, coronary artery bypass graft, and survival was obtained by data linkage with national billing and death registries. Hazard ratios (HR) were calculated using the Cox proportional hazards model with adjustment for baseline characteristics. RESULTS: From 1991 to 1999, there were 10,294 patients who survived > or = 3 days of MI. Of these, 40.6% underwent coronary angiography and 16.5% a revascularization procedure < or = 28 days. Malays received substantially less angiography (34.0%) and revascularization (11.4%) than Chinese (41.9%, 17.9%) and South Asians (40.0%, 16.3%). The ethnic disparity increased during the 1990s, particularly in the performance of coronary angiography (p = 0.038). While fatality declined during the study period for Chinese and South Asians, the rate remained stable for Malays. After a median follow-up period of 4.1 years, survival was lowest among Malays (adjusted HR, 1.28; 95% confidence interval, 1.15-1.42, compared with Chinese). CONCLUSION: Ethnic inequalities in invasive cardiac procedures exist in Singapore and were exacerbated in the 1990s. Inequalities in medical care may contribute to the poorer longterm survival among Malays.

Adult↗
PubMed2004

Clinical impact of stent construction and design in percutaneous coronary intervention.

Convincing end point data demonstrating the anatomic and clinical superiority of stent placement compared with balloon angioplasty together with significant improvement in stenting technique and poststent management have resulted in an explosion in stenting procedures and the emergence of more than 40 stent types with disparate designs and material composition in clinical use. Structural nuances in design, composition, and coating of different stent models, however, have been shown to have a major influence on the risk of stent thrombosis, the degree of vessel wall injury, and subsequent intimal proliferation in the experimental model. There is now substantial amount of evidence to indicate that the same relationship between stent structural characteristics and vessel wall outcome holds true in humans. This article provides an up-to-date overview of the clinical impact of stent construction and design, including the clinical performance of drug-eluting stents.

Biocompatible Materials↗
PubMed2004

Clinical impact of functional testing strategy among stented and non-stented patients: insights from the ROSETTA Registry.

UNLABELLED: The clinical utility of routine functional testing following percutaneous coronary intervention (PCI) among patients with and without coronary stenting is unclear. We established an international registry to evaluate the functional testing strategies following successful PCI. Among patients treated with stents, adverse cardiovascular outcomes were similar between those who underwent routine or clinically-driven functional testing. Conversely, among those who were not treated with stents, the rate of death, myocardial infarction or unstable angina was lower than those who underwent routine functional testing (14.8% vs. 6.6%; P=0.033). Our study suggests that routine functional testing may be beneficial to patients not treated with stents. BACKGROUND: The role of routine functional testing following successful PCI is unclear. By improving patient outcomes with coronary stenting, the value of such a strategy may diminish. HYPOTHESIS: To determine the clinical utility of routine functional testing following PCI between patients with and without stenting. METHODS: The routine versus selective exercise testing after angioplasty (ROSETTA) Registry was established to evaluate the utilization of functional testing following PCI. Use of functional testing, either routine or selective (clinically-driven), was left to the discretion of the attending physician. RESULTS: Of 791 patients enrolled, 462 (58%) underwent coronary stenting. Stented patients were less likely to suffer from concomitant diseases but had more complex angiographic morphological characteristics. Between the groups of patients with and without stents, there was no difference in the proportion of patients undergoing routine functional testing (24% vs. 36%) or subsequent cardiac procedures (18.4% vs. 16.0%). Among patients with stents, outcomes at 6 months were similar between the groups undergoing routine and selective functional testing, including death (0% vs. 1.7%), myocardial infarction (0.9% vs. 2.0%), unstable angina (9.9% vs. 13.7%), repeat angiography (16.2% vs. 16.9%) and revascularization procedures (11.7% vs. 10.8%). However, among non-stented patients, selective functional testing was associated with a higher occurrence of death, myocardial infarction or unstable angina (14.8% vs. 6.6%; P=0.033). There was also no difference in the rates of repeat coronary angiography or revascularization procedures between these two strategies. CONCLUSION: Although routine functional testing has little impact on outcomes among patients treated with coronary stents, non-stented patients may derive particular benefit.

Angioplasty, Balloon, Coronary↗
PubMed2004

Utility of routine functional testing after percutaneous transluminal coronary angioplasty: results from the ROSETTA registry.

BACKGROUND: There is little consensus regarding the use of functional testing after percutaneous transluminal coronary angioplasty (PTCA). Some physicians employ a routine functional testing strategy, and others employ a symptom-driven strategy. OBJECTIVE: To examine the effects of routine post-PTCA functional testing on the use of follow-up cardiac procedures and clinical events. METHODS: The Routine versus Selective Exercise Treadmill Testing after Angioplasty (ROSETTA) Registry is a prospective multicenter observational study examining the use of functional testing after PTCA. A total of 788 patients (pts) were enrolled in the ROSETTA Registry at 13 clinical centers in 5 countries. The frequencies of functional testing, cardiac procedures and clinical events were examined during the first 6 months following a successful PTCA. RESULTS: Patients were predominantly elderly men (mean age, 61+/-11 years; 76% male) who underwent single-vessel PTCA (85%) with stent implantation (58%). During the 6-month follow-up, a total of 237 pts were observed to undergo a routine functional testing strategy (100% having functional testing for routine follow-up), while 551 pts underwent a selective (or clinically-driven) strategy (73% having no functional testing and 27% having functional testing for a clinical indication). Patients in the routine testing group underwent a total of 344 functional tests compared with 165 tests performed in the selective testing group (mean, 1.45 tests/patient versus 0.3 tests/patient; p<0.0001). There was little difference in the rates of follow-up cardiac procedures among the pts undergoing the routine and selective testing strategies [cardiac catheterization, 13.9% versus 17.5% (p=NS); percutaneous coronary intervention (PCI), 8.4% versus 8.7% (p=NS); coronary artery bypass graft surgery, 2.1% versus 3.3% (p=NS)]. However, clinical events were less common among pts who underwent routine functional testing, e.g., unstable angina (6.1% versus 14.4%; p=0.001), myocardial infarction (0.4% versus 1.6%; p=NS), death (0% versus 2.2%; p=0.02) and composite clinical events (6.3% versus 16.3%; p<0.0001). After controlling for baseline clinical and procedural differences, routine functional testing had a persistent independent association with a reduction in the composite clinical event rate (odds ratio, 0.45; 95% confidence interval, 0.24-0.81; p=0.008). CONCLUSION: Routine functional testing after PTCA is associated with a reduction in the frequency of follow-up clinical events. This association may be attributable to the early identification and treatment of pts at risk for follow-up events, or it may be due to clinical differences between pts who are referred for routine and selective functional testing.

Angioplasty, Balloon, Coronary↗
PubMed2004

Comparison between glycoprotein IIb/IIIa blockade and distal protection device for the restoration of myocardial perfusion during percutaneous coronary intervention for acute myocardial infarction.

We compared the use of abciximab with a distal balloon occlusion device in preserving myocardial perfusion among patients undergoing acute percutaneous coronary intervention for ST-segment elevation myocardial infarction. Of 114 patients, 40 were treated with abciximab and 74 with distal protection. Although pre-treatment with abciximab resulted in marginally better myocardial perfusion at initial coronary angiography, distal protection emerged superior at the end of the procedure. The use of distal protection was associated with an adjusted odds of 4 (p = 0.017) for achieving normal myocardial perfusion and adjusted reduction of 11 corrected TIMI frame counts (p = 0.001) compared with abciximab.

Abciximab↗
PubMed2003

Clinical studies on coronary revascularization in patients with type 2 diabetes.

With the increasing prevalence, diabetes is rapidly growing into a global public health problem. Cardiovascular disease is a major consequence of this chronic condition, and a critical issue facing physicians worldwide today is choice of coronary revascularization procedures in treating these patients. Since the Bypass Angioplasty Revascularization Investigation (BARI) alert in 1995, there have been several reports on subgroup analysis of clinical trials and registries concerning revascularization among patients with diabetes. Although randomized control studies comparing percutaneous and surgical revascularization procedures in this high-risk group of patients are lacking, this article provides the background for the excess risk and reviews the findings of these investigations. Current strategies to improve outcomes in patients with diabetes undergoing coronary revascularization procedures are discussed.

Atherectomy, Coronary↗
PubMed2003

Medical therapy in patients undergoing percutaneous coronary intervention: results from the ROSETTA registry.

BACKGROUND: Previous studies have examined medication use among patients with coronary artery disease who have suffered an acute myocardial infarction (MI). However, little is known about medication use among patients with coronary artery disease who undergo percutaneous coronary intervention (PCI). OBJECTIVE: To examine the patterns of use of medical therapy among patients who undergo PCI; and to examine the determinants of medical therapy in these patients. METHODS: The Routine versus Selective Exercise Treadmill Testing after Angioplasty (ROSETTA) registry is a prospective multicentre study examining the use of functional testing after PCI. The medication use was examined among 787 patients who were enrolled in the ROSETTA registry at 13 clinical centres in five countries. RESULTS: Most patients were men (mean age 61+/-11 years, 76% male) who underwent single vessel PCI (85%) with stent implantation (58%). At admission, discharge and six months, rates of acetylsalicylic acid use were 77%, 96% and 93%, respectively (discharge versus six months, P<0.0001). Rates of use of other oral antiplatelet agents were 11%, 59% and 2% (P=0.02). For individual anti-ischemic medications, rates of use were as follows: beta-blockers 49%, 58% and 59% (P<0.0001); calcium antagonists 34%, 43% and 42% (P<0.0001); and nitrates 42%, 56% and 43% (P<0.0001). Rates of use of combination anti-ischemic medications were as follows: triple therapy 7%, 9% and 9% (P<0.0001); double therapy 34%, 47% and 38% (P<0.0001); monotherapy 36%, 36% and 41% (P<0.0001); and no anti-ischemic therapy 23%, 8% and 12% (P<0.0001). Rates of use of angiotensin-converting enzyme inhibitors were 25%, 33% and 32% (P<0.0001), and rates of use of lipid lowering agents were 41%, 52% and 61% (P<0.0001). CONCLUSIONS: Trials and guidelines statements have favourably affected the rates of use of acetylsalicylic acid and other antiplatelet agents after PCI. However, in spite of patients undergoing a successful revascularization procedure, physicians do not reduce the use of anti-ischemic medical therapy.

Adrenergic beta-Antagonists↗
PubMed2002

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.

Abciximab↗
PubMed2002

Early and late clinical and angiographic outcomes following terumo coronary stent implantation.

The Terumo stent is a new, balloon-expandable, stainless-steel device with a unique multicellular design to provide robust radial force and end-stoppers to prevent dislodgement. We evaluated the early and late clinical and angiographic outcomes of Terumo coronary stent implantation in native coronary arteries using an open, nonrandomized 3-center registry. From July 1998 to June 1999, a total of 118 Terumo stents were implanted in 105 patients (mean age, 58 +/- 10 years). A significant proportion of patients suffered from diabetes (34%), prior myocardial infarction (MI; 43%) and unstable angina (31%). Most target lesions (48%) had unfavorable morphological characteristics (type B2 or C); mean reference luminal diameter was 2.76 +/- 0.41 mm and lesion length was 11.4 +/- 5.3 mm. Primary success in stent deployment was achieved in 103 patients (98%). There was 1 patient with acute stent thrombosis in whom 2 overlapping stents were deployed. Following stenting, the minimal luminal diameter increased from 1.04 +/- 0.48 mm to 2.39 +/- 0.33 mm. Six-month angiography was performed in 97 patients (92%), and the binary angiographic restenosis (> or = 50% narrowing) rate was 16%. Late loss index was 0.50 +/- 0.43. By 6 months, two patients (1.9%) died, two patients (1.9%) had Q-wave MI and 9 patients (8.4%) required repeat coronary interventions. Therefore, our study shows that the Terumo stent is potentially safe and efficacious in the treatment of coronary narrowings, even in the presence of unfavorable clinical conditions and complex lesion morphological characteristics.

Aged↗