Minimal heparinization in coronary angioplasty--how much heparin is really warranted?

Routine fixed-dose heparin vs. ACT-guided heparin administration for elective PCI and its influence on patient in-hospital outcome: a retrospective study

OBJECTIVE

Activated clotting time (ACT)-based heparin dosing during percutaneous intervention (PCI) is recommended by Society guidelines. However, the relationship between ACT and outcome in the setting of elective PCI has not been sufficiently studied. We sought to evaluate the in-hospital outcome of patients undergoing elective PCI while receiving fixed-dose heparin without ACT measurement versus those with ACT-guided management.

METHODS

This retrospective study included consecutive patients undergoing elective PCI in a single-center between 11/2015 and 12/2018. Patients were divided into two groups, depending on whether ACT was measured. Heparin-only anticoagulation and non-femoral procedures were allowed. Patient demographics, procedural data and in-hospital outcomes were collected. The primary outcome was in-hospital major adverse cardiovascular events (MACE), secondary (safety) outcomes were in-hospital definite stent thrombosis, Bleeding Academic Research Consortium bleeding, access-related complications (any) as well as peri-procedural complications.

RESULTS

In total, 500 procedures were included in the study, 151 ACT and 349 fixed-dose. Patient demographics and medical history in both groups were well balanced, but those having ACTs were younger (63.2 ± 10.9 vs. 66.5 ± 11.3; P = 0.003) and less likely to have a history of coronary artery disease (74 vs. 82%; P = 0.032) or kidney failure. Procedural data were similar; however, total heparin dose and procedure length were higher in the ACT group (6232 ± 1388 vs.5032 ± 417 units; P < 0.001; 40.1 ± 14.0 vs. 30.3 ± 12.7 min; P < 0.001). Primary and secondary outcome events were rare and similar (MACE 1.1 vs. 1.3%; P = 0.86).

CONCLUSIONS

A fixed-dose heparin injection (5000 IU) approach for elective PCI while omitting ACT offers slightly shortened procedural time and similar in-hospital safety profile.

ISAR-REACT 3A: a study of reduced dose of unfractionated heparin in biomarker negative patients undergoing percutaneous coronary intervention

AIMS

Although a 140 U/kg dose of unfractionated heparin (UFH) was comparable with bivalirudin in terms of net clinical outcome in the Intracoronary Stenting and Antithrombotic Regimen: Rapid Early Action for Coronary Treatment (ISAR-REACT) 3 trial, it was associated with a higher risk of bleeding. We designed this study to assess whether a reduction in the UFH dose from 140 to 100 U/kg is associated with improved net clinical outcome.

METHODS AND RESULTS

A total of 2505 biomarker negative patients undergoing percutaneous coronary intervention (PCI) after clopidogrel pre-treatment received a single bolus of 100 U/kg UFH. The primary endpoint was net clinical outcome-a quadruple endpoint of death, myocardial infarction, urgent target-vessel revascularization within 30 days, or in-hospital REPLACE 2 defined major bleeding. The primary comparison was with the historical UFH group of ISAR-REACT 3 (2281 patients). In a second analysis, we checked for non-inferiority against the historical bivalirudin arm of ISAR-REACT 3 (2289 patients). The incidence of the primary endpoint was 7.3% in the lower UFH dose group compared with 8.7% in the higher UFH dose group [hazard ratio (HR) 0.81; 95% confidence interval (CI) 0.67-1.00; P = 0.045]. The incidence of major bleeding was 3.6% in the lower UFH dose group and 4.6% in the higher UFH dose group (HR 0.79; 95% CI 0.59-1.05; P = 0.11). The lower UFH dose met the criterion of non-inferiority compared with bivalirudin (P < 0.001).

CONCLUSION

In biomarker negative patients undergoing PCI after clopidogrel loading, a reduced dose of 100 U/kg UFH provided net clinical benefit compared with the historical control of 140 U/kg UFH in the ISAR-REACT 3 trial. The benefit was mostly driven by reduction in bleeding.

CLINICAL TRIAL REGISTRATION INFORMATION

URL www.clinicaltrials.gov; Unique identifier NCT00735280.

Adjunctive pharmacotherapy for coronary interventions-time to read the writing on the wall

None of the authors has any financial interests to disclose. With the new era of coronary stenting supported by triple anti-platelet therapy, in-hospital life threatening ischemic complications are rare, and minimally affected by the intensity and duration of the anti-coagulation protocol. Bleeding complications, however, became the most commonly observed adversity of percutaneous coronary intervention. Hemorrhagic complications are clearly related to the intensity and duration of anti-coagulation and platelet inhibition protocols, and result in excessive mortality, morbidity, and medical costs. Demographic and clinical predictors of bleeding complications are reviewed. Accumulating data on the safety of PCI with low-dose unfractionated heparin is pointed out. In view of the contemporary data, the authors question the recently published European and American guideline, which suggest uniform dosing and therapeutic targets for both anticoagulants and glycoprotein IIb/IIIa blockers. Instead, we suggest that these agents will be used judiciously and cautiously tailored, bearing in mind their benefits against the potential to harm. After over three decades of PCI, it is time to engage in dose and duration optimizing studies for these agents.

Heparin in interventional radiology: a therapy in evolution

Interventional radiology techniques made possible by the antithrombotic properties of heparin have revolutionized treatment for a myriad of disorders. Newer low-molecular-weight heparins (LMWHs) offer several advantages over unfractionated heparin (UFH), especially in chronic settings. They are increasing in popularity for use during vascular procedures. However, LMWH shares limitations with UFH such as heterogeneity, nonspecificity, and induction of thrombocytopenia. These drawbacks have led to a search for the next generation of antithrombotic agents. Homogeneous drugs targeting specific coagulation cascade molecules are now available. The number of alternative anticoagulant drug combinations presents clinicians with a confusing array of choices. The strengths and weaknesses of UFH, LMWH, and direct antithrombin agents are presented. The promising future of LMWH and hirudins is discussed.

Guidelines for percutaneous coronary interventions. The Task Force for Percutaneous Coronary Interventions of the European Society of Cardiology

In patients with stable CAD, PCI can be considered a valuable initial mode of revascularization in all patients with objective large ischaemia in the presence of almost every lesion subset, with only one exception: chronic total occlusions that cannot be crossed. In early studies, there was a small survival advantage with CABG surgery compared with PCI without stenting. The addition of stents and newer adjunctive medications improved the outcome for PCI. The decision to recommend PCI or CABG surgery will be guided by technical improvements in cardiology or surgery, local expertise, and patients' preference. However, until proved otherwise, PCI should be used only with reservation in diabetics with multi-vessel disease and in patients with unprotected left main stenosis. The use of drug-eluting stents might change this situation. Patients presenting with NSTE-ACS (UA or NSTEMI) have to be stratified first for their risk of acute thrombotic complications. A clear benefit from early angiography (<48 h) and, when needed, PCI or CABG surgery has been reported only in the high-risk groups. Deferral of intervention does not improve outcome. Routine stenting is recommended on the basis of the predictability of the result and its immediate safety. In patients with STEMI, primary PCI should be the treatment of choice in patients presenting in a hospital with PCI facility and an experienced team. Patients with contra-indications to thrombolysis should be immediately transferred for primary PCI, because this might be their only chance for quickly opening the coronary artery. In cardiogenic shock, emergency PCI for complete revascularization may be life-saving and should be considered at an early stage. Compared with thrombolysis, randomized trials that transferred the patients for primary PCI to a 'heart attack centre' observed a better clinical outcome, despite transport times leading to a significantly longer delay between randomization and start of the treatment. The superiority of primary PCI over thrombolysis seems to be especially clinically relevant for the time interval between 3 and 12 h after onset of chest pain or other symptoms on the basis of its superior preservation of myocardium. Furthermore, with increasing time to presentation, major-adverse-cardiac-event rates increase after thrombolysis, but appear to remain relatively stable after primary PCI. Within the first 3 h after onset of chest pain or other symptoms, both reperfusion strategies seem equally effective in reducing infarct size and mortality. Therefore, thrombolysis is still a viable alternative to primary PCI, if it can be delivered within 3 h after onset of chest pain or other symptoms. Primary PCI compared with thrombolysis significantly reduced stroke. Overall, we prefer primary PCI over thrombolysis in the first 3 h of chest pain to prevent stroke, and in patients presenting 3-12 h after the onset of chest pain, to salvage myocardium and also to prevent stroke. At the moment, there is no evidence to recommend facilitated PCI. Rescue PCI is recommended, if thrombolysis failed within 45-60 min after starting the administration. After successful thrombolysis, the use of routine coronary angiography within 24 h and PCI, if applicable, is recommended even in asymptomatic patients without demonstrable ischaemia to improve patients' outcome. If a PCI centre is not available within 24 h, patients who have received successful thrombolysis with evidence of spontaneous or inducible ischaemia before discharge should be referred to coronary angiography and revascularized accordingly--independent of 'maximal' medical therapy.

Safety of coronary stenting with eptifibatide and ultra-low-dose heparin

With the advent of multiple potent antiplatelet and anticoagulation agents in percutaneous coronary intervention (PCI), the risk of bleeding complications has increased. The optimal dose of unfractionated heparin in this setting is unclear. This study was designed to determine the feasibility and safety of PCI with an ultra-low-dose weight-adjusted unfractionated heparin regimen (30 IU/kg bolus, maximum 3,000 IU) in combination with aspirin, clopidogrel, and eptifibatide. We enrolled 83 patients who underwent nonemergency PCI of native coronary arteries. At 30 days, all patients were free of the primary clinical outcomes defined as a composite of death, myocardial infarction, or repeat target vessel revascularization, and there were no major bleeding complications.

Interventional cardiovascular pharmacotherapy: current issues

In the last decade, a variety of novel anticoagulant and antiplatelet agents that improve outcomes in patients undergoing percutaneous coronary revascularization have emerged. During the next decade, continued refinements in catheter-based device technology should lead to further increases in the number of interventional procedures. The use of optimal antithrombotic strategies is pivotal in reducing adverse events among patients undergoing percutaneous coronary intervention (PCI). Our purpose is to review the current evidence regarding the efficacy of available adjunctive anticoagulant and antiplatelet agents in treating patients undergoing percutaneous coronary revascularization. It should be borne in mind that patients undergoing PCI in the midst of an acute coronary event require a different level of coagulation and platelet aggregation inhibition than low-risk patients undergoing elective PCI for stable angina pectoris. Similarly, generalizing antithrombotic regimen safety data to a wide spectrum of catheter-based therapeutic devices should be avoided. A level of anticoagulation that is safe and effective for angioplasty and stent placement may not be sufficient for devices with longer intracoronary dwell times such as brachytherapy catheters. In light of current evidence, activated clotting times should be targeted in the 200- to 250-second range during elective PCI and in the 250- to 300-second range when intervening on a higher-risk lesion, such as one with an angiographically visible thrombus or in patients presenting with an acute coronary syndrome (ACS).Low-dose enoxaparin sodium is an attractive antithrombin strategy in PCI because it is intrinsically adjusted for renal function, age, and concomitant glycoprotein (GP) IIb/IIIa antagonist use. Other low-molecular weight heparins have also been studied as adjunctive anticoagulants during cardiac catheterization. For example, in pilot studies, dalteparin sodium was shown to have a good safety profile when used alone or in combination with abciximab during PCI.A wealth of data supports the use of a GP IIb/IIIa antagonist in patients presenting with ACS, especially those with high-risk features such as elevated cardiac markers; the systematic use of GP IIb/IIIa inhibitors in this population is therefore encouraged. Overall, the use of GP IIb/IIIa inhibitors reduces the incidence of thrombotic complications following PCI, is associated with a mortality benefit, but has no impact on the risk of restenosis.

Revisiting optimal anticoagulation with unfractionated heparin during coronary stent implantation

Using univariate and multivariate analyses, we evaluated the relation between ischemic and bleeding complications and peak procedural activated clotting time (ACT) in patients undergoing percutaneous coronary intervention whose coronary narrowings were treated with stent implantation. Of the 2,280 patients who qualified for the study, 29% had diabetes mellitus, and 91% received glycoprotein IIb/IIIa inhibitors. The median for ACT was 276 seconds (interquartile range 243 to 317). The incidence of ischemic events by ACT quartiles was 6.3%, 7.5%, 8.1%, and 7.1%, respectively (p=0.71). The incidence of bleeding complications was 6.6%, 5.9%, 6.9%, and 7.3%, respectively (p=0.81). ACT did not independently predict either ischemic or hemorrhagic complications.

Direct stenting with 3000 i.u. heparin

In order to reduce vascular complications, the authors assessed safety and feasability of a new percutaneous transluminal coronary angioplasty (PTCA) strategy consisting of direct stenting with 3000 i.u. heparin and immediate sheath removal. Predicting factors of vascular complications during PTCA include heparin dosages, sheath dwell time and use of anti-glycoprotein (GP) IIb/IIIa. A simplified PTCA with direct stenting technique may allow the use of very low doses of heparin without anti-GPIIb/IIIa in selected cases. From April 1999 to April 2000 all patients who underwent PTCA in the authors' center were screened. Exclusion criteria comprised a contraindication for direct stenting, primary PTCA for acute myocardial infarction (MI) and a TIMI (thrombolysis in myocardial infarction) grade zero flow. All other patients were included. They received 3000 i.u. heparin before direct stenting whatever their current anticoagulation and their weight. The sheath was immediately removed using manual compression. Out of 716 consecutive PTCA patients, 171 (24%) were enrolled in the study (198 sites). Complete protocol was achieved in 150 patients (88%). Activated clotting time during the procedure was 179 +/- 32 seconds. No subacute thrombosis or creatine kinase elevation was observed before discharge. Only two uncomplicated groin hematomas and two false aneurysms (one surgical repair) were noted. This study shows that direct stenting with 3000 iu heparin is safe. Immediate sheath removal can be performed with a low rate of major vascular complications.

Activated clotting time or activated partial thromboplastin time as the method of choice for patients undergoing neuroradiological intervention

We evaluated the role of the activated clotting time (ACT) and activated partial thromboplastin time (APTT), both currently available as bedside tests, for monitoring anticoagulation following bolus injection of 2500 or 5000 IU heparin in 21 patients undergoing neuroradiological procedures. APTT was measured using the CoaguChek Pro device compared to the laboratory standard measurement and ACT comparing CoaguChek Pro to Hemochron Celite and Kaolin. Statistical analysis was performed using Bablok-Passing regression. Despite heparin doses of 2500-5000 IU APTT measurements were out of range in 67% of patients using CoaguChek Pro and in 76.5% of patients using the laboratory measurement. ACT was reliably determined in all patients. The correlation between the different devices (CoaguChek Pro vs. Hemochron Celite r=0.69, Kaolin r=0.78) and assays (Hemochron Celite/Kaolin r=0.85) was good. ACT ranged from 141-417 s measured by CoaguChek Pro and 138-320 s measured by Hemochron Celite and 172-381 s using Hemochron Kaolin. These results indicate that ACT is the method of choice for monitoring anticoagulation in neuroangiographic procedures.

A unique, low dose of intravenous enoxaparin in elective percutaneous coronary intervention

OBJECTIVES

This study was designed to examine a unique and low dose of intravenous enoxaparin in elective percutaneous coronary intervention (PCI) that would be applicable to an unselected population regardless of age, weight, renal function, or use of glycoprotein IIb/IIIa inhibitors.

BACKGROUND

There is limited experience of anticoagulation using intravenous (IV) low-molecular-weight heparin in PCI, which has been obtained with high doses causing elevated anticoagulation levels and delayed sheath withdrawal.

METHODS

A total of 242 consecutive patients undergoing elective PCI were treated with a single IV bolus of enoxaparin (0.5 mg/kg), and 26% of patients (n = 64) also received eptifibatide. Sheaths were removed immediately after the procedure in patients treated with enoxaparin only, and 4 h after the procedure in those also treated with eptifibatide.

RESULTS

A peak anti-Xa >0.5 IU/ml was obtained in 97.5% of the population, and 94.6% of patients had their peak anti-Xa level in the predefined target range of 0.5 to 1.5 IU/ml. Advanced age, renal failure, being overweight, and eptifibatide use did not alter the anticoagulation profile. At one-month follow-up, six patients (2.5%) had died, had a myocardial infarction, or undergone an urgent revascularization; all the patients had an anti-Xa level >0.5 IU/ml during PCI. Patients without an ischemic event and without a creatine kinase rise, but with a detectable troponin release in the next 24 h of PCI (>2 microg/ml, n = 21), had similar anti-Xa levels as those without troponin elevation. There were one major and three minor bleeding events that were not associated with anti-Xa overshoot.

CONCLUSIONS

Low-dose (0.5 mg/kg) IV enoxaparin allows a prespecified target level of anticoagulation (anti-Xa >0.5 IU/ml) in the vast majority of patients undergoing PCI, appears to be safe and effective, allows immediate sheath removal when used alone, and does not require dose adjustment when used with eptifibatide.

Low-molecular-weight heparin therapy for non-ST-elevation acute coronary syndromes and during percutaneous coronary intervention: an expert consensus

BACKGROUND

Therapy with either low-molecular-weight heparin (LMWH) or glycoprotein (GP) IIb/IIIa receptor antagonists is of benefit to patients with acute coronary syndromes (ACSs). However, algorithms that define how LMWH may be used in patients, proceeding from medical management to intervention and in conjunction with GP IIb/IIIa inhibitors, are lacking. The objectives of this task force were to formulate recommendations based on all available data for the use of LMWH, both with and without GP IIb/IIIa receptor antagonists, and to provide seamless integration of care during the transition from medical to interventional management.

METHODS AND RESULTS

An international task force of 14 cardiologists with extensive experience in clinical trials was convened in New York in February 2001 to address issues related to the use of LMWH in patients with non-ST-elevation ACS. Evidence from randomized trials, observational studies, and other reports was discussed, and consensus recommendations were formulated.

CONCLUSIONS

Substantial evidence exists that patients receiving LMWH for an ACS can safely undergo cardiac catheterization and percutaneous coronary intervention. Concerns regarding the transition of these patients from the medical service to the cardiac catheterization laboratory should therefore not impede the upstream use of LMWH. Furthermore, LMWH and GP IIb/IIIa receptor antagonists can be used safely in combination, with no apparent increase in the risk of major bleeding. Consensus algorithms for therapy are presented.

Heparin dose during percutaneous coronary intervention: how low dare we go?

Despite dramatic advances in percutaneous coronary intervention, including coronary stents and potent antiplatelet agents, unfractionated heparin remains the standard procedural anticoagulant. Tradition and habit may have considerable influence over dose selection. A review of the role and dosage of heparin during PCI appears to be overdue

Relationship between activated clotting time during percutaneous intervention and subsequent bleeding complications

BACKGROUND

Approximately 50% of percutaneous coronary interventions in the United States are performed with unfractionated heparin and no IIb/IIIa agent. The operator must weigh the risks and benefits of more intensive anticoagulation during these percutaneous interventions. This study helps clarify the relationship between patient and procedural factors, such as the intensity of heparin anticoagulation as measured by activated clotting time (ACT), and the risk of blood loss and bleeding complications.

METHODS

Four hundred twenty-nine patients undergoing elective or urgent percutaneous coronary intervention were followed up prospectively for 72 hours after intervention for clinical bleeding complications. Blood loss, defined as the difference between preprocedural and nadir postprocedural hematocrit adjusted for interval transfusions, was also tracked. In-laboratory ACTs, as well as other potential clinical and procedural predictors of blood loss and bleeding risk, were collected and analyzed.

RESULTS

Maximum in-laboratory ACT was significantly related to blood loss as measured by the change in hematocrit (P =.017) and to the risk of major bleeding complications (P =.002). In multivariate analysis, patient age (P =.004), sex (P =.014), procedure length (P <.001), and additional interventions (P <.001) were significant, independent predictors of blood loss. Major bleeding complications were significantly, independently predicted by patient age (P <.001), additional interventions (P =.015), and maximum in-laboratory ACT (P <.001).

CONCLUSIONS

Compared with the other clinical and procedural predictors of bleeding complications, maximum in-laboratory ACT was second only to patient age in significance as a multivariate predictor of postprocedural bleeding complications. Maximum in-laboratory ACT was found to be the most significant modifiable univariate and multivariate predictor of clinical bleeding complications after percutaneous coronary intervention. Particularly in patients with nonmodifiable risk factors for blood loss and bleeding complications such as advanced age, female sex, and multiple and prolonged procedures, avoiding high intensity anticoagulation with unfractionated heparin is associated with lower bleeding risk.

Unfractionated versus fractionated heparin for percutaneous coronary intervention

Since the advent of percutaneous coronary intervention (PCI), intravenous unfractionated heparin has been the primary antithrombotic therapy to prevent periprocedural ischemic complications. As compared with unfractionated heparin, low molecular weight heparins (LMWHs) have a greater bioavailability and a more predictable therapeutic response. In several recent studies of patients undergoing PCI, LMWHs have been shown to be as safe and effective as unfractionated heparin; given their better pharmacokinetic profile and the lack of need for coagulation monitoring, they have the potential to replace unfractionated heparin during coronary interventions. This article reviews the current status of anticoagulation therapy with unfractionated heparin and LMWHs in the cardiac catheterization laboratory.

Immediate protamine administration and sheath removal following percutaneous coronary intervention: a prospective study of 429 patients

We tested the approach of reversing anticoagulation following PCI and immediate sheath removal in 429 consecutive patients. On completion of the PCI, protamine was administered, and the vascular sheath was immediately removed. Stents were used in 364 patients (85%) and GP IIb/IIIa inhibitors were used in 52 patients (12%). Time to achieve hemostasis was 30 +/- 17 min. Minor groin bleeding occurred in six patients. One patient required repair of femoral pseudoaneurysm. Mean creatine kinase at 8 and 16 hr post-PCI were 129 +/- 35 and 145 +/- 32 units, respectively. Creatine kinase rose to > 3 times normal in 12 out of 350 patients (3.4%). Prior to 48 hr, eight patients (1.9%) required emergency PCI or coronary bypass surgery. Follow-up at 30 days observed no deaths and only three target vessel revascularizations (0.7%). In conclusion, immediate reversal of anticoagulation and sheath removal after PCI is safe and feasible.

New recommendations from the 1999 American College of Cardiology/American Heart Association acute myocardial infarction guidelines

OBJECTIVE

To review literature relating to significant changes in drug therapy recommendations in the 1999 American College of Cardiology (ACC)/American Heart Association (AHA) guidelines for treating patients with acute myocardial infarction (AMI).

DATA SOURCES

1999 ACC/AHA AMI guidelines, English-language clinical trials, reviews, and editorials researching the role of drug therapy and primary angioplasty for AMI that were referenced in the guidelines were included. Additional data published in 2000 or unpublished were also included if relevant to interpretation of the guidelines.

STUDY SELECTION

The articles selected influence AMI treatment recommendations.

DATA SYNTHESIS

Many clinicians and health systems use the ACC/AHA AMI guidelines to develop treatment plans for AMI patients. This review highlights important changes in AMI drug therapy recommendations by reviewing the results of recent clinical trials. Insights into evolving drug therapy strategies that may impact future guideline development are also described.

CONCLUSIONS

Several changes in drug therapy recommendations were included in the 1999 AMI ACC/AHA guidelines. There is emphasis on administering fibrin-specific thrombolytics secondary to enhanced efficacy. Selection between fibrin-specific agents is unclear at this time. Low response rates to thrombolytics have been noted in the elderly, women, patients with heart failure, and those showing left bundle-branch block on the electrocardiogram. These patient groups should be targeted for improved utilization programs. The use of glycoprotein (GP) IIb/IIIa receptor inhibitors in non-ST-segment elevation MI was emphasized. Small trials combining reduced doses of thrombolytics with GP IIb/IIIa receptor inhibitors have shown promise by increasing reperfusion rates without increasing bleeding risk, but firm conclusions cannot be made until the results of larger trials are known. Primary percutaneous coronary intervention (PCI) trials suggest lower mortality rates for primary PCI when compared with thrombolysis alone. However, primary PCI, including coronary angioplasty, is only available at approximately 13% of US hospitals, making thrombolysis the preferred strategy for most patients. Clopidogrel has supplanted ticlopidine as the recommended antiplatelet agent for patients with aspirin allergy or intolerance following reports of a better safety profile. The recommended dose of unfractionated heparin is lower than previously recommended, necessitating a separate nomogram for patients with acute coronary syndromes. Routine use of warfarin, either alone or in combination with aspirin, is not supported by clinical trials; however, warfarin remains a choice for antithrombotic therapy in patients intolerant to aspirin. Beta-adrenergic receptor blockers continue to be recommended, and emphasis is placed on improving rates of early administration (during hospitalization), even in patients with moderate left ventricular dysfunction. New recommendations for drug treatment of post-AMI patients with low high-density lipoprotein cholesterol and/or elevated triglycerides are included, with either niacin or gemfibrozil recommended as an option. Supplementary antioxidants are not recommended for either primary or secondary prevention of AMI, with new data demonstrating lack of efficacy vitamin E in primary prevention. Estrogen replacement therapy or hormonal replacement therapy should not be initiated solely for prevention of cardiovascular disease, but can be continued in cardiovascular patients already taking long-term therapy for other reasons. Bupropion has been added as a new treatment option for smoking cessation. As drug therapy continues to evolve in treating AMI, more frequent updates of therapy guidelines will be necessary.

Defining the optimal activated clotting time during percutaneous coronary intervention: aggregate results from 6 randomized, controlled trials

BACKGROUND

Unfractionated heparin has been the primary anticoagulant therapy for percutaneous coronary intervention for >20 years. Despite the availability of rapid "point of care" testing, little clinical data defining the optimal level of anticoagulation are available. Furthermore, recent reports have advocated the use of low-dose heparin regimens in the absence of large-scale, well-conducted studies to support this practice.

METHODS AND RESULTS

We pooled the data from 6 randomized, controlled trials of novel adjunctive antithrombotic regimens for percutaneous coronary interventions in which unfractionated heparin constituted the control arm. Patients were divided into 25-s intervals of activated clotting times (ACTs), from <275 s to >476 s. In a total of 5216 patients, the incidence of death, myocardial infarction, or any revascularization and major or minor bleeding at 7 days were calculated for each group and compared. An ACT in the range of 350 to 375 s provided the lowest composite ischemic event rate of 6.6%, or a 34% relative risk reduction in 7-day ischemic events compared with rates observed between 171 and 295 s by quartile analysis (P=0.001).

CONCLUSIONS

Contrary to recent reports, the optimal suppression of ischemic events with unfractionated heparin therapy in patients undergoing percutaneous coronary intervention demands treatment to ACT levels that are substantially higher than currently appreciated. These data define a goal for heparin dosing within coronary interventions and establish a benchmark of optimal unfractionated heparin therapy against which future trials of novel antithrombotic regimens in percutaneous interventions can be compared.

Antiplatelet and anticoagulant therapy in elective percutaneous coronary intervention

Thrombosis plays a major role in acute vessel closure both after coronary balloon angioplasty and after stenting. This review will address the role of antiplatelet and anticoagulant therapy in preventing early thrombotic complications after percutaneous coronary intervention. The focus will be on agents that are routinely available and commonly used.