A randomized trial confirming the efficacy of reduced dose recombinant tissue plasminogen activator in a Chinese myocardial infarction population and demonstrating superiority to usual dose urokinase: the TUCC trial

Platelet Membrane-Coated r-SAK Improves Thrombolytic Efficacy by Targeting Thrombus

Thrombolytic therapy is one of the most effective treatments for thrombus dissolution and recanalization of blocked vessels in thrombotic diseases. However, the application of the thrombolytic strategy has been limited due to unsatisfactory thrombolytic efficacy, relatively higher bleeding complications, and consequently restricted indications. Recombinant staphylokinase (r-SAK) is a third-generation thrombolytic agent produced by genetic engineering technology, which exhibits a better thrombolytic efficacy than urokinase and recombinant streptokinase. Inspired by the natural affinity of platelets in hemostasis and pathological thrombosis, we developed a platelet membrane (PM)-coated r-SAK (PM-r-SAK). Results from animal experiments and human in vitro studies showed that the PM-r-SAK had a thrombolytic efficacy equal to or better than its 4-fold dose of r-SAK. In a totally occluded rabbit femoral artery thrombosis model, the PM-r-SAK significantly shortened the initial recanalization time compared to the same dose and 4-fold dose of r-SAK. Regarding the recanalized vessels, the PM-r-SAK prolonged the time of reperfusion compared to the same dose and 4-fold dose of r-SAK, though the differences were not significant. An in vitro thrombolytic experiment demonstrated that the thrombolytic efficacy of PM-r-SAK could be inhibited by platelet-poor plasma from patients taking aspirin and ticagrelor. PM coating significantly improves the thrombolytic efficacy of r-SAK, which is related to the thrombus-targeting activity of the PM-r-SAK and can be inhibited by aspirin- and ticagrelor-treated plasma.

Tenecteplase versus alteplase in treatment of acute ST-segment elevation myocardial infarction: A randomized non-inferiority trial

BACKGROUND

A phase II trial on recombinant human tenecteplase tissue-type plasminogen activator (rhTNK-tPA) has previously shown its preliminary efficacy in ST elevation myocardial infarction (STEMI) patients. This study was designed as a pivotal postmarketing trial to compare its efficacy and safety with rrecombinant human tissue-type plasminogen activator alteplase (rt-PA) in Chinese patients with STEMI.

METHODS

In this multicenter, randomized, open-label, non-inferiority trial, patients with acute STEMI were randomly assigned (1:1) to receive an intravenous bolus of 16 mg rhTNK-tPA or an intravenous bolus of 8 mg rt-PA followed by an infusion of 42 mg in 90 min. The primary endpoint was recanalization defined by thrombolysis in myocardial infarction (TIMI) flow grade 2 or 3. The secondary endpoint was clinically justified recanalization. Other endpoints included 30-day major adverse cardiovascular and cerebrovascular events (MACCEs) and safety endpoints.

RESULTS

From July 2016 to September 2019, 767 eligible patients were randomly assigned to receive rhTNK-tPA ( n = 384) or rt-PA ( n = 383). Among them, 369 patients had coronary angiography data on TIMI flow, and 711 patients had data on clinically justified recanalization. Both used a -15% difference as the non-inferiority efficacy margin. In comparison to rt-PA, both the proportion of patients with TIMI grade 2 or 3 flow (78.3% [148/189] vs. 81.7% [147/180]; differences: -3.4%; 95% confidence interval [CI]: -11.5%, 4.8%) and clinically justified recanalization (85.4% [305/357] vs. 85.9% [304/354]; difference: -0.5%; 95% CI: -5.6%, 4.7%) in the rhTNK-tPA group were non-inferior. The occurrence of 30-day MACCEs (10.2% [39/384] vs. 11.0% [42/383]; hazard ratio: 0.96; 95% CI: 0.61, 1.50) did not differ significantly between groups. No safety outcomes significantly differed between groups.

CONCLUSION

rhTNK-tPA was non-inferior to rt-PA in the effect of improving recanalization of the infarct-related artery, a validated surrogate of clinical outcomes, among Chinese patients with acute STEMI.

TRIAL REGISTRATION

www.ClinicalTrials.gov (No. NCT02835534).

Systemic reduced-dose alteplase for diffuse pulmonary thrombi in a COVID-19 patient

Pulmonary embolism has a high frequency in COVID-19 patients admitted to the intensive care unit. Low level of fibrinolysis is one of the asserted contributors to a prothrombotic state in COVID-19. Thrombotic coagulopathy is mostly encountered as diffuse pulmonary thrombi. Diffuse pulmonary microemboli was treated successfully with reduced dose thrombolysis.

Fibrinolytic therapy use for ST-segment elevation myocardial infarction and long-term outcomes in China: 2-year results from the China Acute Myocardial Infarction Registry

BACKGROUND

Data on fibrinolytic therapy use for ST-segment elevation myocardial infarction (STEMI) and long-term clinical outcomes in developing countries are limited. We aimed to investigate the management and 2-year mortality of fibrinolytic-treated patients in China.

METHODS

A total of 19,112 patients with STEMI from 108 hospitals participated in the China Acute Myocardial Infarction registry between January 2013 and September 2014. We investigated the 2-year all-cause mortality among patients treated with fibrinolysis. Non-invasive clinical indexes were used to diagnose successful fibrinolysis or not.

RESULTS

Only 1823 patients (9.5%) enrolled in the registry underwent fibrinolysis and 679 (37.2%) could be treated within 3 h after symptom onset. The overall use of rescue percutaneous coronary intervention was 8.9%. Successful fibrinolysis, which could be achieved in 1428 patients (78.3%), was related to types of fibrinolytic agents, symptom to needle time, infarction site, and Killip class. Follow-up data were available for 1745 patients (95.7%). After multivariate adjustment, successful fibrinolysis was strongly associated with a decreased risk of death compared with failed fibrinolysis at 2 years (8.5% vs. 29.0%, hazard ratio: 0.27, 95% confidence interval: 0.20-0.35).

CONCLUSION

Within a minority of STEMI patients in the CAMI registry underwent fibrinolysis, most of them could achieve successful clinical reperfusion, presenting a much benign 2-year survival outcome than those with failed fibrinolysis. Quality improvement initiatives focusing on fibrinolysis are warranted to achieve its promise fully.

TRIAL REGISTRATION

URL: https// www.

CLINICALTRIALS

gov . Unique identifier: NCT01874691. Registered 11/06/2013.

The recanalization after thrombolysis as surrogate for clinical outcomes in patients with ST-segment elevation acute myocardial infarction: A systematic review and meta-regression analysis of data from randomized controlled trials

AIMS

Thrombolytic therapy has been known to be effective in reducing clinical outcomes and increasing recanalization rate among patients with ST-segment elevation acute myocardial infarction (STEMI). However, whether post-thrombolysis recanalization could be used as a surrogate for clinical outcomes is unknown.

METHODS

We systematically searched PubMed, EMBASE and the Cochrane Library database to identify randomized controlled trials (RCT) that examined effects of thrombolytic agents in STEMI. Recanalization was defined as TIMI grade 2 or 3 flow. The primary outcome was in-hospital all-cause mortality. Secondary outcomes included in-hospital and 30-day recurrent myocardial infarction (re-MI), composite of death and re-MI, major bleeding and all bleeding. Random-effects meta-regression was used for analysis.

RESULTS

We identified 111 eligible study arms and 52 eligible comparisons from 58 RCTs involving 16 536 patients. Our analyses showed that among study arms recanalization rate was significantly inversely associated with the incidence of in-hospital all-cause mortality (β: -0.07, 95% confidence interval [CI]: -0.13 to -0.02), re-MI (β: -0.09, 95%CI: -0.18 to -0.01) and the composite of death and re-MI (β: -0.17, 95%CI: -0.28 to -0.05), and positively associated with in-hospital all bleeding but not with major bleeding. Among paired comparisons, the difference in recanalization rate was associated with the corresponding difference in incidence of in-hospital all-cause mortality (β: -0.15, 95%CI: -0.28 to -0.01) but the relationship was not significant for any other outcome.

CONCLUSION

Pooled evidence from RCTs suggest the potential use of recanalization as a surrogate for clinical outcomes in evaluating the efficacy of thrombolysis among patients with STEMI.

Spontaneous intermuscular hematoma in a patient receiving ticagrelor and aspirin: A case report

Dual antiplatelet therapy is a cornerstone treatment following percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS). Ticagrelor, a direct-acting potent P2Y12 inhibitor, is superior to clopidogrel in the acute setting of ACS: due to its faster onset and potent antiplatelet inhibition. Thus, ticagrelor is becoming widely recommended as the as the initial treatment following PCI in current guidelines. However, due to its potency, the risk of bleeding is higher. Herein, a report of an unusual case of spontaneous intermuscular hematoma is described. Furthermore, single-nucleotide polymorphisms that may be related to bleeding in ticagrelor using population-based genome-wide association studies were also identified and are discussed. As there is a concern that patients of Asian origin may have a higher risk of bleeding, physicians must be made aware of this risk when prescribing ticagrelor to individuals of Asian decent.

The effect of tranexamic acid in unilateral and bilateral total knee arthroplasty in the South Asian population: A retrospective cohort study

INTRODUCTION

Together with evidence of higher bleeding tendencies, the vulnerability of the South-Asian population to anemia secondary to a higher prevalence of hemoglobinopathies and micronutrient deficiencies merits further exploration of the effects of tranexamic acid on this population. Additionally, limited access to self-care facilities and certain sociocultural beliefs and practices may not be conducive to a speedy recovery from surgical complications. The aim of this study is to investigate the effects of intraoperative administration of tranexamic acid during total knee arthroplasty when considering the South-Asian population.

METHODOLOGY

Medical record files of 355 patients who underwent total knee arthroplasty (2007-2015) were reviewed to collect data regarding patient characteristics, surgical variables and post-operative complications. Unilateral and Bilateral total knee arthroplasty were studied separately. Analysis was done using t-test, Mann-Whitney U test, chi-square and Fisher's exact square where appropriate. The threshold for significance was p < 0.05.

RESULTS

The study showed that for unilateral surgery, tranexamic acid caused a significant reduction in estimated blood loss (p-value=0.011), total operative time, calculated blood loss, and hemoglobin change (p-value<0.001) whereas in bilateral surgery, tranexamic acid only caused a significant reduction in calculated blood loss (p-value < 0.001) and hemoglobin change (p-value=0.001). Interestingly, in those who received tranexamic acid vs. those who did not, there was a significant increase in length of hospital stay (p<0.001) and special care unit admissions (p-value=0.033) in unilateral and bilateral surgery respectively.

CONCLUSIONS

Although tranexamic acid effectively reduces intraoperative blood loss, it does not have an effect on the need for post-operative blood transfusions. The increased length of stay and special care unit admissions associated with tranexamic acid use should be explored further to reveal the complete safety profile of tranexamic acid administration in the South-Asian population during total knee arthroplasty.

Recombinant human TNK tissue-type plasminogen activator (rhTNK-tPA) versus alteplase (rt-PA) as fibrinolytic therapy for acute ST-segment elevation myocardial infarction (China TNK STEMI): protocol for a randomised, controlled, non-inferiority trial

AIM

To evaluate the efficacy and safety of recombinant human TNK tissue-type plasminogen activator (rhTNK-tPA) in lowering major adverse cardiovascular and cerebrovascular events (MACCEs) in Chinese acute ST-segment elevation myocardial infarction (STEMI) patients.

METHODS AND ANALYSIS

The study is designed as a multicentre, randomised, controlled non-inferiority phase IV trial with balanced randomisation (1:1) in patients with STEMI. The planned sample size is 6200 participants (or 3100 per arm). Participants with STEMI will be randomised to receive either rhTNK-tPA or alteplase (rt-PA), with stratification by research centre, age and the time from symptom onset to randomisation. All patients will receive concomitant antiplatelet and anticoagulant therapy before fibrinolytic therapy. The participants assigned to the intervention group will receive an intravenous bolus of 16 mg rhTNK-tPA, while those assigned to the control group will receive an intravenous bolus of 8 mg rt-PA followed by 42 mg infusion over 90 mins. Other medications can also be administered at the discretion of the cardiologists in charge. All participants will be followed up for the primary study endpoint, the occurrence of MACCEs within 30 days after fibrinolytic therapy, which is defined as all-cause mortality, non-fatal re-infarction, non-fatal stroke, percutaneous coronary intervention (PCI) due to thrombolysis failure, and PCI due to reocclusion. Both intention-to-treat and per-protocol analyses will be done for the primary analyses.

ETHICS AND DISSEMINATION

The study procedures and informed consent form were approved by all participating hospitals. The results will be disseminated in peer review journals and academic conferences. This multicentre randomised controlled trial will provide high-quality data about the efficacy and safety of rhTNK-tPA and, once approved, its easier use should help improve the application of reperfusion therapy and hence the treatment outcomes of STEMI patients.

TRIAL REGISTRATION NUMBER

NCT02835534.

Higher Risk of Bleeding in Asians Presenting With ST-Segment Elevation Myocardial Infarction: Analysis of the National Inpatient Sample Database

Bleeding is a major complication in patients presenting with ST-segment elevation myocardial infarction (STEMI). Several studies suggested that Asians are more susceptible to bleeding when treated with antiplatelets, anticoagulants, and thrombolytic agents. In our study, we aimed to investigate the association between Asian ethnicity and bleeding events in patients who presented with STEMI. We analyzed the Nationwide Inpatient Sample database from 2002 to 2013 and identified patients hospitalized with a primary diagnosis of STEMI. We compared clinical outcomes between patients of Asian and white ethnicity. Primary outcome was inhospital major bleeding defined as a composite of intracranial hemorrhage and blood transfusions for bleeding events. After exclusions, an estimated 1 695 680 white and 46 563 Asian patients with STEMI were included in the analysis. Asian patients had a higher incidence of inhospital major bleeding (3.6% vs 2.2%, P < .001) without a significant difference in inhospital mortality (9.3% vs 8.7%, P = .06). Asian ethnicity was an independent predictor for major bleeding (estimated odds ratio: 1.32; 95% confidence interval: 1.16-1.51; P < .001). This increased risk of bleeding would warrant further investigation of optimal treatment strategies tailored for patients with STEMI of Asian ethnicity.

Efficacy and Safety of a Pharmaco-Invasive Strategy With Half-Dose Alteplase Versus Primary Angioplasty in ST-Segment-Elevation Myocardial Infarction: EARLY-MYO Trial (Early Routine Catheterization After Alteplase Fibrinolysis Versus Primary PCI in Acute ST-Segment-Elevation Myocardial Infarction)

BACKGROUND

Timely primary percutaneous coronary intervention (PPCI) cannot be offered to all patients with ST-segment-elevation myocardial infarction (STEMI). Pharmaco-invasive (PhI) strategy has been proposed as a valuable alternative for eligible patients with STEMI. We conducted a randomized study to compare the efficacy and safety of a PhI strategy with half-dose fibrinolytic regimen versus PPCI in patients with STEMI.

METHODS

The EARLY-MYO trial (Early Routine Catheterization After Alteplase Fibrinolysis Versus Primary PCI in Acute ST-Segment-Elevation Myocardial Infarction) was an investigator-initiated, prospective, multicenter, randomized, noninferiority trial comparing a PhI strategy with half-dose alteplase versus PPCI in patients with STEMI 18 to 75 years of age presenting ≤6 hours after symptom onset but with an expected PCI-related delay. The primary end point of the study was complete epicardial and myocardial reperfusion after PCI, defined as thrombolysis in myocardial infarction flow grade 3, thrombolysis in myocardial infarction myocardial perfusion grade 3, and ST-segment resolution ≥70%. We also measured infarct size and left ventricular ejection fraction with cardiac magnetic resonance and recorded 30-day clinical and safety outcomes.

RESULTS

A total of 344 patients from 7 centers were randomized to PhI (n=171) or PPCI (n=173). PhI was noninferior (and even superior) to PPCI for the primary end point (34.2% versus 22.8%, P_{noninferiority}<0.05, P_superiority=0.022), with no significant differences in the frequency of the individual components of the combined end point: thrombolysis in myocardial infarction flow 3 (91.3% versus 89.2%, P=0.580), thrombolysis in myocardial infarction myocardial perfusion grade 3 (65.8% versus 62.9%, P=0.730), and ST-segment resolution ≥70% (50.9% versus 45.5%, P=0.377). Infarct size (23.3%±11.3% versus 25.8%±13.7%, P=0.101) and left ventricular ejection fraction (52.2%±11.0% versus 51.4%±12.0%, P=0.562) were similar in both groups. No significant differences occurred in 30-day rates of total death (0.6% versus 1.2%, P=1.0), reinfarction (0.6% versus 0.6%, P=1.0), heart failure (13.5% versus 16.2%, P=0.545), major bleeding events (0.6% versus 0%, P=0.497), or intracranial hemorrhage (0% versus 0%), but minor bleeding (26.9% versus 11.0%, P<0.001) was observed more often in the PhI group.

CONCLUSIONS

For patients with STEMI presenting ≤6 hours after symptom onset and with an expected PCI-related delay, a PhI strategy with half-dose alteplase and timely PCI offers more complete epicardial and myocardial reperfusion when compared with PPCI. Adequately powered trials with this reperfusion strategy to assess clinical and safety outcomes are warranted.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT01930682.

Total knee Arthroplasty: risk factors for allogeneic blood transfusions in the South Asian population

BACKGROUND

Total knee arthroplasty (TKA) is the recommended treatment for end-stage knee osteoarthritis. Considering the various risks associated with intra and postoperative blood transfusions, better understanding is required with respect to the risk factors contributing to a greater possibility of blood transfusion during or after surgery. Although literature highlights several such factors, our study is among the first to identify these risk factors in the South Asian population which differs from other populations in several ways.

METHODS

The study consists of a review of 658 patients undergoing TKA from 2005 to 2015. Data was obtained from patient medical records and was analysed using logistic regression analysis. The relationship between each predictor and the outcome variable was calculated as an Odds ratio (OR), the threshold of significance for which was p = 0.25 and p = 0.05 for univariate and multivariable analysis respectively.

RESULTS

The mean age of the patient population was 63 years (78% female), 25% of whom received one or more blood transfusions. Multivariable analysis revealed 5 significant independent predictors for increased risk of blood transfusions including bilateral knee surgery (OR:5.51), preoperative anemia (OR:4.15), higher ASA (American Society of Anaesthesiologists) status (3-4) (OR:1.92), female sex (OR:3.44) and BMI (Body mass index) ≤30 (OR:1.79) while increasing co-morbidities and age (>60) were found to be insignificant.

CONCLUSIONS

The factors identified for the South Asian population are largely similar to those for other populations. Identification of high risk patients will permit the application of an international multipronged approach which not only targets the modifiable risk factors but also the decision making process and blood management protocols in order to minimize the transfusion associated risks for a patient undergoing a TKA.

Fibrinolytic therapy in hospitals without percutaneous coronary intervention capabilities in China from 2001 to 2011: China PEACE-retrospective AMI study

BACKGROUND

Fibrinolytic therapy is the primary reperfusion strategy for ST-segment elevation myocardial infarction in China, and yet little is known about the quality of care regarding its use and whether it has changed over time. This issue is particularly important in hospitals without the capacity for cardiovascular intervention.

METHODS

Using a sequential cross-sectional study with two-stage random sampling in 2001, 2006, and 2011, we characterised the use, timing, type and dose of fibrinolytic therapy in a nationally representative sample of patients with ST-segment elevation myocardial infarction admitted to hospitals without the ability to perform percutaneous coronary intervention.

RESULTS

We identified 5306 patients; 2812 (53.0%) were admitted within 12 hours of symptom onset, of whom 2463 (87.6%) were ideal candidates for fibrinolytic therapy. The weighted proportion of ideal candidates receiving fibrinolytic therapy was 45.8% in 2001, 50.0% in 2006, and 53.0% in 2011 ( P_trend=0.0042). There were no regional differences in fibrinolytic therapy use. Almost all ideal patients (95.1%) were treated after admission to the hospital rather than in the emergency department. Median admission to needle time was 35 minutes (interquartile range 10-82) in 2011, which did not improve from 2006. Underdosing was common. Urokinase, with little evidence of efficacy, was used in 90.2% of patients.

CONCLUSIONS

Over the past decade in China, the potential benefits of fibrinolytic therapy were compromised by underuse, patient and hospital delays, underdosing and the predominant use of urokinase, an agent for which there is little clinical evidence. There are ample opportunities for improvement.

Low-Dose Versus Standard-Dose Tissue Plasminogen Activator in Acute Ischemic Stroke in Asian Populations: A Meta-Analysis

Recent studies have investigated the most efficacious dose of intravenous tissue plasminogen activator (IV-tPA) for acute ischemic stroke (AIS) patients. There remains no definitive consensus concerning the superior efficacious IV-tPA dose (standard- vs. low-dose), prompting us to perform a meta-analysis comparing the efficacy and safety profile of standard- versus low-dose IV-tPA.We identified relevant studies pertaining to the specific aim of our meta-analysis by searching PubMed and EMBASE (January 1990-September 2015) Either a fixed- or random-effects model was employed (dependent upon data heterogeneity) to analyze the efficacy and safety outcome.Ten cohort studies involving 4389 sum patients were included in the meta-analysis. By using the random-effects model, the meta-analysis indicated no statistically significant difference in favorable functional outcome (modified Rankin scale 0-1) at 3 months (heterogeneity: χ = 17.45, P = 0.04, I = 48%; OR: 0.88 [95% CI: 0.71-1.11]; P = 0.28) and incidence of symptomatic intracranial hemorrhage (SICH) (heterogeneity: χ = 14.41, P = 0.11, I = 38%; OR: 1.19 [95% CI: 0.76 to 1.87]; P = 0.45) between the standard- and low-dose groups. The fixed-effects model demonstrated no significant difference in mortality within 3 months (heterogeneity: χ = 6.73, P = 0.57, I = 0%; OR: 0.91 [95% CI: 0.73-1.12]; P = 0.37) between the standard- and low-dose groups.Low-dose IV-tPA is comparable to standard-dose IV-tPA in both efficacy (favorable functional outcome) and safety (SICH and mortality). Confirmation of these findings through randomized trials is warranted.

Ticagrelor versus clopidogrel in Asian patients with acute coronary syndrome: A retrospective analysis from the Platelet Inhibition and Patient Outcomes (PLATO) Trial

BACKGROUND

In the PLATO trial, ticagrelor was superior to clopidogrel in reducing cardiovascular events among patients with acute coronary syndrome (ACS) at the expense of increased nonfatal bleeding. Because Asian patients, when compared with non-Asian patients, are believed to be more susceptible to bleeding, we evaluated the effects of ticagrelor compared with clopidogrel in Asian (n=1,106) and non-Asian (n=17,515) patients with acute coronary syndrome enrolled in the PLATO study.

METHODS AND RESULTS

Interaction between Asian/non-Asian and primary efficacy end point (a composite of vascular death, myocardial infarction, and stroke) and net clinical benefit (composite of primary efficacy end point and coronary artery bypass graft [CABG] surgery or non-CABG-related major bleeding) were evaluated with a Cox proportional hazards model. Baseline demographics and comorbidities were different between Asians and non-Asians. The overall cardiovascular event rates were higher in Asians, but bleeding rates were similar. Despite these observed differences, the effects of ticagrelor versus clopidogrel were not significantly different between Asians and non-Asians with respect to the primary efficacy outcome (hazard ratio for Asians vs non-Asians, 0.84 [95% CI 0.61-1.17] vs 0.85 [95% CI 0.77-0.93], P=.974), net clinical benefit (0.85 [95% CI 0.65-1.11] vs 0.93 [95% CI 0.86-0.99], P=.521), or individual efficacy end points. There was no significant interaction for bleeding (PLATO major bleeding, 1.02 [95% CI 0.70-1.49] vs 1.04 [95% CI 0.95-1.14], P=.938) and other related adverse events with ticagrelor compared with clopidogrel between Asians and non-Asians.

CONCLUSIONS

We observed consistency of effects in Asian patients receiving ticagrelor and clopidogrel in the PLATO study. The relatively modest number of Asian patients in this analysis supports further investigation of larger cohorts to confirm our observations.

Different doses of recombinant tissue-type plasminogen activator for acute stroke in Chinese patients

BACKGROUND AND PURPOSE

The relationship between the dose of recombinant tissue-type plasminogen activator (r-tPA) and its safety/efficacy for ischemic stroke has not been well evaluated in the East Asian population. We assessed the safety/efficacy of different doses of r-tPA for acute ischemic stroke in Chinese patients.

METHODS

A total of 1004 eligible patients were classified according to the dose of r-tPA received for managing acute ischemic stroke: 0.9 mg/kg (n=422), 0.8 mg/kg (n=202), 0.7 mg/kg (n=199), and 0.6 mg/kg (n=181). The safety outcome was symptomatic intracerebral hemorrhage and death within 3 months. The efficacy outcome was good functional outcome (modified Rankin Scale ≤1) at 3 months.

RESULTS

There was a significant trend for symptomatic intracerebral hemorrhage with age (P=0.002). With multivariate logistic regression analysis, a dose of 0.9 mg/kg was a predictor of symptomatic intracerebral hemorrhage (P=0.0109), and a dose ≤0.65 mg/kg was a predictor of good functional outcome (P=0.0369). In patients aged 71 to 80 years, there was a significant trend of increasing symptomatic intracerebral hemorrhage (P=0.0130) and less good functional outcome (P=0.0179) with increasing doses of r-tPA. There was also a trend of increasing mortality (P=0.0971) at 3 months in these patients.

CONCLUSIONS

These results did not support the dose of 0.9 mg/kg of r-tPA being optimal for all patients in the East Asian population. In elderly patients (71-80 years), a lower dose of 0.6 mg/kg is associated with a better outcome. Confirmation of the results through randomized trial is required.

Comparison of bleeding and in-hospital mortality in Asian-Americans versus Caucasian-Americans with ST-elevation myocardial infarction receiving reperfusion therapy

Concern has been raised that Asian-Americans may have a higher bleeding risk than Caucasian-Americans when treated with fibrinolytic and antithrombotic agents. To date there is limited evidence to support or refute this hypothesis or evaluate bleeding risk and its related outcomes in Caucasian-Americans versus Asian-Americans with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary interventions (PPCI). We evaluated Asian-Americans and Caucasian-Americans with STEMI receiving reperfusion therapy in the National Registry of Myocardial Infarction (NRMI) 4 and 5 (n = 90,317). We studied risk-adjusted major bleeding and in-hospital mortality. Major bleeding rates after fibrinolysis were similar in Asian-Americans (n = 705) and Caucasian-Americans (n = 42,243, 11.1% vs 10.3%, adjusted odds ratio [OR] 0.97, 95% confidence interval [CI] 0.69 to 1.36, p = 0.5002). Although the observed major bleeding rate was higher in Asian-Americans (n = 1,037) compared to Caucasian-Americans (n = 46,332) treated with PPCI (10.3% vs 7.8%, p = 0.0036), these rates differed only marginally after adjusting for baseline clinical variables (OR 1.24, 95% CI 0.97 to 1.59). Overall adjusted mortality was similar in Asian-Americans and Caucasian-Americans when treated with fibrinolysis (OR 0.96, 95% CI 0.56 to 1.65) or with PPCI (OR 1.35, 95% CI 0.85 to 2.13). Major bleeding after PPCI or fibrinolysis was associated with similar increased risks for mortality in these ethic groups. In conclusion, despite suggestions to the contrary, Asian-Americans with STEMI treated with fibrinolysis or PPCI had similar bleeding and bleeding-related mortality risks compared to Caucasian-Americans. Given the genotypic and phenotypic differences between the 2 cohorts, similar studies in the rapidly growing Asian-American population are needed to confirm our findings and to understand the safety and effectiveness of newer potent antiplatelet and antithrombotic agents in patients with coronary syndromes.

Genetic polymorphisms of cytochrome P450 enzymes 2C9 and 2C19 in a healthy Mongolian population in China

We examined the distribution of major allelic variants of CYP2C9 and CYP2C19 in the Mongolian population of China and compared it with that of other populations. The polymorphisms of CYP2C9 (including the CYP2C9*1, CYP2C9*2 and CYP2C9*3 alleles) and CYP2C19 (including the CYP2C19*1, CYP2C19*2 and CYP2C19*3 alleles) were analyzed in 280 healthy unrelated Chinese Mongolian subjects, using a PCR-RFLP assay. The frequencies of CYP2C9*1, *2 and *3 alleles were 0.97, 0.00 and 0.03, respectively. The frequencies of CYP2C19*1, *2 and *3 alleles were 0.72, 0.24 and 0.04, respectively. We did not find any differences in the allelic distribution of these two genes between age groups. However, the genotype frequency of CYP2C9 *1/*3 was significantly higher in males than in females. Compared with other populations, we found that the allele frequencies of the CYP2C9*2 and CYP2C9*3 allelic variants in this Mongolian population of China were similar to those reported for other Asian populations, with significant differences compared to Caucasians and African-Americans.

Outcomes of thrombolytic therapy for acute ischemic stroke in Chinese patients: the Taiwan Thrombolytic Therapy for Acute Ischemic Stroke (TTT-AIS) study

BACKGROUND AND PURPOSE

The safety and efficacy of alteplase for ischemic stroke has not been examined in Chinese patients. We assessed the safety and efficacy of alteplase for acute ischemic stroke in daily clinical practice in Taiwan.

METHODS

A prospective, multicenter, observational study was conducted in Taiwan from December 2004 to July 2008. Eligible patients (241) receiving alteplase were recruited and divided into 2 groups: standard dose (0.90 + or - 0.02 mg/kg, n=125) and lower dose (0.72 + or - 0.07 mg/kg, n=116). Primary outcome measures were safety: symptomatic intracerebral hemorrhage and death within 3 months. The secondary outcome measure was efficacy a modified Rankin scale of 0 to 2 after 3 months.

RESULTS

The standard-dose group had higher rates of symptomatic intracerebral hemorrhage using National Institute of Neurological Diseases and Stroke, European Cooperative Acute Stroke Study, and Safe Implementation of Thrombolysis in Stroke-Monitoring Study definitions (10.4% versus 5.2%, 8.0% versus 2.6%, and 5.6% versus 1.7%, respectively) and mortality within 3 months (12.8% versus 6.9%), twice that of the lower-dose group. This pattern was more prominent in older patients. Significantly higher rates of symptomatic intracerebral hemorrhage per European Cooperative Acute Stroke Study (15.4% versus 3.3%, P=0.0257) and mortality (21.1% versus 5.0%, P=0.0099) and significantly lower independence rate (32.6% versus 53.6%, P=0.0311) were observed among patients > or = 70 years old receiving the standard dose than those receiving the lower dose.

CONCLUSIONS

This study suggests that the standard dose of 0.9 mg/kg alteplase may not be optimal for treating aged Chinese patients. However, the dose of recombinant tissue plasminogen activator for ischemic stroke in Chinese patients should be based on more broad and convincing evidences and randomized trials of lower versus higher doses are needed.

Efficacy and safety of low dose recombinant tissue-type plasminogen activator for the treatment of acute pulmonary thromboembolism: a randomized, multicenter, controlled trial

Background

Optimal dosing of the recombinant tissue-type plasminogen activator (rt-PA) is important in treating pulmonary thromboembolism (PTE). The aim of this study was to compare the efficacy and safety of a 50 mg/2 h rt-PA regimen with a 100 mg/2 h rt-PA regimen in patients with acute PTE.

Methods

A prospective, randomized, multicenter trial was conducted in which 118 patients with acute PTE and either hemodynamic instability or massive pulmonary artery obstruction were randomly assigned to receive a treatment regiment of either rt-PA at 50 mg/2 h (n = 65) or 100 mg/2 h (n = 53). The efficacy was determined by observing the improvements of right ventricular dysfunctions (RVDs) on echocardiograms, lung perfusion defects on ventilation perfusion lung scans, and pulmonary artery obstructions on CT angiograms. The adverse events, including death, bleeding, and PTE recurrence, were also evaluated.

Results

Progressive improvements in RVDs, lung perfusion defects, and pulmonary artery obstructions were found to be similarly significant in both treatment groups. This is true for patients with either hemodynamic instability or massive pulmonary artery obstruction. Three (6%) patients in the rt-PA 100 mg/2 h group and one (2%) in the rt-PA 50 mg/2 h group died as the result of either PTE or bleeding. Importantly, the 50 mg/2 h rt-PA regimen resulted in less bleeding tendency than the 100 mg/2 h regimen (3% vs 10%), especially in patients with a body weight < 65 kg (14.8% vs 41.2%, P = .049). No fatal recurrent PTE was found in either group.

Conclusions

Compared with the 100 mg/2 h regimen, the 50 mg/2 h rt-PA regimen exhibits similar efficacy and perhaps better safety in patients with acute PTE. These findings support the notion that optimizing rt-PA dosing is worthwhile when treating patients with PTE.

Trial registration

clinicaltrials.gov; Identifier: NCT00781378

Comparison of baseline characteristics, treatment patterns, and in-hospital outcomes of Asian versus non-Asian white Americans with non-ST-segment elevation acute coronary syndromes from the CRUSADE quality improvement initiative

It has been suggested that Asians may respond differently to antithrombotic therapy, but contemporary management and outcomes of non-ST-segment elevation (NSTE) acute coronary syndromes (ACSs) in Asian patients have not been well characterized. Using data from the CRUSADE initiative, we compared baseline characteristics, treatment patterns, and in-hospital outcomes between 1,071 Asian and 72,513 non-Asian white patients hospitalized with NSTE ACS. Asian patients were more likely to have hypertension, diabetes, and renal insufficiency compared with non-Asian whites. Body mass index was lower in Asian patients (24.9 vs 27.8 kg/m(2), p <0.0001). Use of acute medical therapies, cardiac catheterization, and percutaneous or surgical revascularization did not significantly differ between Asian and white groups after adjustment for patient and hospital characteristics. In-hospital mortality (5.0% vs 4.4%, adjusted odds ratio [OR] 1.24, 95% confidence interval [CI] 0.88 to 1.73) and reinfarction rates (2.0% vs 2.3%. adjusted OR 0.94, 95% CI 0.65 to 1.38) were also similar. In contrast, rates of major bleeding (13.4% vs 9.4%, p <0.0001) and red blood cell transfusion (9.6% vs 6.6%, p = 0.0005) were significantly higher in the Asian population and this higher bleeding risk persisted after adjustment for bleeding risk factors and body mass index; adjusted ORs were 1.32 (95% CI 1.08 to 1.62) and 1.32 (95% CI 1.01 to 1.72), respectively. In conclusion, despite similar treatment, Asian patients with NSTE ACS have significantly higher bleeding risk even after adjustment for risk factors and body mass index. Further investigation is needed to explore the potential for ethnic variability in antithrombotic susceptibility.

Time to reperfusion in acute myocardial infarction. It is time to reduce it!

BACKGROUND AND OBJECTIVES

Mortality from ST-segment elevation myocardial infarction remains high, with most deaths occurring before hospital admission. Despite effective pre- and in-hospital reperfusion strategies becoming standard over the past 2 decades, time-to-admission and time-to-treatment remain prolonged. We reviewed temporal trends in these times in published clinical trials.

METHODS

All major randomized clinical trials reporting on reperfusion strategies for acute myocardial infarction published between 1993 and 2003 were evaluated. Strategies included pre- and in-hospital thrombolysis, primary percutaneous coronary intervention (pPCI) with or without transfer, and "facilitated" PCI. We generated overall estimates of time-to-admission, time-to-treatment, door-to-balloon (DTB), and door-to-needle (DTN) times and evaluated temporal trends in the length of time-to-admission and time-to-treatment.

RESULTS

In studies that evaluated only in-hospital thrombolysis, the time-to-admission was 149 +/- 45 minutes; the mean time-to-treatment was 181 +/- 29 minutes. In studies that considered only in-hospital pPCI (without transfer), the mean time-to-admission was 153 +/- 41 minutes; the mean time-to-treatment was 234 +/- 43 minutes. In studies that compared in-hospital pPCI with in-hospital thrombolytic therapy, the mean time-to-admission was 155 +/- 47 and 150 +/- 48 minutes, respectively. The DTN time was 65 +/- 10 minutes, whereas DTB time was 81 +/- 39 minutes. In other trials evaluating in-hospital thrombolysis and pPCI with transfer to a referral center, the time-to-admission in subjects treated with thrombolysis (n = 1345) was 127 +/- 32 minutes vs 131 +/- 36 minutes for pPCI (n = 1528). For in-hospital thrombolysis, time-to-treatment was 151 +/- 23 minutes vs 203 +/- 15 minutes for pPCI patients with transfer. The DTN time in the thrombolysis group was 44 +/- 28 minutes as compared with DTB time of 78 +/- 38 minutes in the pPCI group. Throughout the last decade, time-to-admission decreased significantly (P = .02) but time-to-treatment remained unchanged (P = .38) for patients undergoing thrombolysis. In the pPCI arm, time-to-admission remained unchanged (P = .11) but a insignificant trend toward reduction was demonstrated in time-to-treatment (P = .11).

CONCLUSION

Time-to-admission and time-to-treatment for ST-segment elevation myocardial infarction are still prolonged. Resources should be directed to early recognition of the acute myocardial infarction, improved utilization of emergency services for transportation, and prehospital diagnosis and triaging. Ambulances equipped with wireless capability to transmit electrocardiograms to the on-call cardiologist seem to be promising tools to achieve earlier diagnosis and triaging with high diagnostic sensitivity and specificity.

The high prevalence of the poor and ultrarapid metabolite alleles of CYP2D6, CYP2C9, CYP2C19, CYP3A4, and CYP3A5 in Taiwanese population

Genetic polymorphisms of drug metabolizing enzymes, such as cytochromes P450 (CYPs), play major roles in the variations of drug responsiveness in human. The aim of this study is to identify the high prevalence (minor allele frequencies >1%) of the abnormal metabolite alleles of CYP2C9, CYP2C19, CYP2D6, CYP3A4, and CYP3A5 in the Taiwanese population. The genotyping of the functional single nucleotide polymorphisms (SNPs) of CYPs were conducted by direct exon sequencing in 180 Taiwanese volunteers. Twenty-one unique SNPs including three newly identified SNPs were detected in the Taiwanese population. Six of the 21 SNPs in five genes showed frequencies more than 1%. The results indicated that it could be very useful and important in developing an inexpensive, convenient, and precise genotyping method for the high prevalence of CYPs metabolizing abnormal alleles in the Taiwanese population.

Cilostazol: Potential mechanism of action for antithrombotic effects accompanied by a low rate of bleeding

Treatment of thrombotic disease requires a delicate balance between prevention of new thrombotic events and management of bleeding complications. Various antiplatelet and anticoagulant agents have been used to this end, with varying degrees of success. Among the antiplatelet agents tested so far, cilostazol, which selectively targets phosphodiesterase III (PDE-III), has unique features. Cilostazol is classified as an antiplatelet agent because it inhibits the platelet aggregation induced by collagen, 5'-adenosine diphosphate (ADP), epinephrine, and arachidonic acid. Unlike other antiplatelet agents cilostazol not only inhibits platelet function but also improves endothelial cell function. Platelets circulate throughout the body with continuous tethering on the surface of endothelial cells. When endothelial cells are stimulated, the number of activated, or pre-conditioned, platelets in circulation increases. These platelets enhance thrombus formation at the sites of endothelial disruption. Cilostazol effectively prevents the onset of thrombotic disease, not only by direct inhibition of platelet function, but also by reducing the number of activated or pre-conditioned platelets in circulation. Secondary prevention of stroke with modest increase in bleeding complications was achieved by administration of cilostazol in the Japanese Cilostazol Stroke Prevention Study done in Japan. These results suggest that cilostazol may reduce the risk of stroke without increasing the risk of bleeding complications.

Global patterns of health care for acute coronary syndromes

PURPOSE OF REVIEW

Despite similar guidelines, remarkable global differences exist in the management of acute coronary syndromes. This review describes recent insights in global patterns of patient baseline characteristics, treatment strategies, medication use, and outcome in acute coronary syndromes.

RECENT FINDINGS

Results from recent registries and randomized clinical trials suggest that the arrival of many novel medications and treatment options for acute coronary syndromes has led to interregional heterogeneity in the management and treatment of patients with acute coronary syndromes. These differences in health care and adherence to national and international guidelines appear to be influenced by geographical, social, cultural, and economic factors, resulting in regional variation in hospital characteristics, physician attitude, access to resources or advanced cardiovascular care, access to the literature, and the availability of drugs.

SUMMARY

Significant differences in diagnosis and treatment of acute coronary syndrome patients can be observed globally, despite similar guidelines based on the same randomized clinical trials. Guidelines are not adapted promptly worldwide, influencing outcome and health care expenditure.

Toward individualized pharmaceutical care of East Asians: the value of genetic testing for polymorphisms in drug-metabolizing genes

Research into the relationship between genetics and drug response has focused on polymorphisms in genes that encode drug-metabolizing enzymes, particularly the genes of cytochrome P450 superfamily 2, which affect the clearance of the anticoagulant warfarin, proton pump inhibitors, tricyclic antidepressants, and many other clinically relevant drugs. Much of this work has targeted East Asians, a genetically distinguishable and populous group. Researchers have identified polymorphisms that inactivate gene function, compared polymorphism frequencies in East-Asian and Caucasian populations, and determined the effects on the pharmacokinetic parameters of drugs. Detection in an individual of polymorphisms known to inactivate a drug-metabolizing enzyme is predictive of poor metabolism of drugs processed by that pathway, which itself may be predictive of an atypical drug response. Genetic tests can be used to screen for individuals with poor metabolizer phenotypes, with the ultimate goal of predicting the clinical effects of drugs.

The current state of cardiology in China

Cardiology in China has shown significant changes in the last decade or so. Interventional cardiology, in particular, has shown remarkable advances, especially in the management of coronary artery disease, which, unfortunately, has shown a disconcerting increase in incidence in a country traditionally known for very low incidence of coronary artery disease. Important contributing factors include increasing affluence, westernization of dietary habit and lifestyle, and rampant cigarette smoking. At present, the Chinese population has an annual coronary mortality of one sixth of that reported in the West, an incidence of acute myocardial infarction of one tenth to one eighth, and a mortality of acute myocardial infarction of one eighth. The prevalence of coronary artery disease among the general Chinese population (3-7%) is roughly one quarter of that among the Caucasians in the West, but this will get worse for sure. China still has a lot of catching up to do to reach full modernization. There is a price that every developing country must pay for modernization. However, let the price the Chinese pay not exceed the benefits derived from modernization. Can we achieve a utopian stage in the 21st century in which the modern Chinese retain their ancestral low rates of coronary artery disease while adapting the positive aspects of a modern western lifestyle?

The era of genomics: impact on sepsis clinical trial design

OBJECTIVE

This article aims to address the predictable impact of genetics on the design of clinical trials in the field of critical care medicine, with emphasis on the pathophysiology of sepsis and its treatment.

DATA SOURCES

Published articles reporting studies on sepsis and septic shock or assessing the influence of genetics and pharmacogenomics in the treatment of critical illnesses.

DATA ANALYSIS

Because most common diseases including sepsis have been shown to be influenced by inherited differences in our genes, completion of the Human Genome Project and the concomitant publication of the human single nucleotide polymorphism map both contribute to change our approach to medicine. Advances in genotyping techniques and bioinformatics enabling detection of single nucleotide polymorphisms have caused an explosion in pharmacogenomics-the research dealing with the interactions of an individual's genotype and the outcome of a drug therapy. Pharmacogenomics will undoubtedly be used to improve future health care and clinical research in different ways. Whereas treatment allocation has been based mainly on phenotype, genetic characterization will help researchers to identify suitable subjects for clinical trials, to facilitate interpretation of the results of clinical trials, and to identify novel targets for future drugs or new markets for current products. As interindividual variability in drug response is a substantial clinical problem, the second major objective of pharmacogenomic research is to decrease adverse responses to therapy through determination of adequate therapeutic targets and genetic polymorphisms that alter drug specificity and toxicity. Ultimately, genetic information will be used to select the most effective therapeutic agent and the optimal dosage to elicit the expected drug response for a given individual. Implementation of genetic criteria for stratification of patient populations and individual assessment of treatment risks and benefits emerges as a major challenge to the pharmaceutical industry.

CONCLUSIONS

In the future, technologies such as gene chip array will enhance genetic medicine and provide novel insights into a patient's susceptibility to disease, enabling a better assessment of prognostic risk factors, quicker diagnosis, and accurate prediction of individual responsiveness to drugs. The predictable consequences of such an approach on the prevention and treatment of diseases could revolutionize medicine.

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.