Heparin dosing in patients undergoing coronary intervention.

Unfractionated heparin remains an essential component of the antithrombotic regimen in patients undergoing coronary intervention, although the timing, dosing, and duration of heparin therapy have evolved over the past several years. Complications associated with heparin use include bleeding events, which occur in 3.9-16.4% of patients receiving conventional heparin. Less commonly, clinically significant thrombocytopenia develops, related to the duration of heparin administration. In patients undergoing coronary intervention who do not receive platelet glycoprotein (GP) IIb/IIIa inhibitors, sufficient heparin should be given to achieve an activated clotting time (ACT) of 250-300 seconds with the HemoTec device and 300-350 seconds with the Hemochron device. There is a general trend to use lower, weight-adjusted heparin dosing (70-100 units/kg) to avoid excessive levels of anticoagulation, with additional heparin boluses to achieve a therapeutic ACT level. When GP IIb/IIIa inhibitors are used, weight-adjusted heparin dosing can be decreased to 70 units/kg to achieve a target ACT of 200 seconds with either the HemoTec or Hemochron device. After uncomplicated coronary intervention, there appears to be little value associated with continued heparin therapy, and the risk of bleeding complications clearly increases with longer durations and higher levels of anticoagulation after coronary intervention.

Impact of end-stage renal disease on clinical and angiographic outcomes after coronary stenting.

Although patients with end-stage renal disease (ESRD) are at high risk for restenosis that requires repeat revascularization after balloon angioplasty, their restenosis rate after coronary stenting is still unknown. Over a 4-year period, we performed coronary stenting on 40 lesions in 34 patients with ESRD. We compared these lesions with 80 lesions from patients without renal disease who underwent coronary stenting in the STARS and WINS clinical trials, matched for treatment site, diabetes, lesion length, and reference vessel diameter. Quantitative coronary angiography was performed on all lesions and clinical outcomes were assessed at 9-month follow-up. Clinical and angiographic characteristics were well matched between the 2 groups and acute clinical success rates were similar. Despite comparable initial angiographic results over the 9-month follow-up period, repeat target lesion revascularization was twice as frequent in the ESRD group compared with the control group (35% vs 16%, p <0.05). After adjusting for differences in postprocedural minimum lumen diameter and other angiographic and clinical characteristics, ESRD remained the most important predictor of late target lesion revascularization (relative risk = 2.3, p = 0.04). In addition, overall 9-month mortality was higher for ESRD patients than for the control population (18% vs 2%, p <0.01). Thus, despite similar angiographic results, patients with ESRD are at higher risk for target lesion revascularization after coronary stenting than controls. Nonetheless, most patients with ESRD do not develop restenosis after stent placement, suggesting an important role for stenting in the management of this challenging population.

Profound symptomatic bradycardia associated with combined mibefradil and beta-blocker therapy.

We report two cases where the addition of mibefradil to long term beta-blocker therapy in managing hypertension produced profound symptomatic bradycardia requiring cardiac pacing. Reports of a number of interactions between mibefradil and other cardioactive drugs have now led to its withdrawal from the market worldwide.

Clinical trials in interventional cardiology.

Several well-designed, randomized trials and registries have recently been completed in patients undergoing percutaneous coronary intervention (PCI) for the treatment of symptomatic coronary artery disease. These studies have further clarified the value of newer pharmacologic and mechanical approaches to patients with atherosclerotic disease and have resulted in improved clinical outcomes in patients undergoing PCI. As a result, many of the older paradigms of lesion-specific device selection have been revised to include the intricate balance of devices and drugs, tailored to the specific clinical presentation and lesion morphology in patients undergoing PCI. This article reviews several recent clinical trials and discusses their impact on early and late outcomes in patients undergoing PCI for symptomatic coronary artery disease.

Coronary Revascularization in Patients with Acute Coronary Syndromes.

Non-Q wave myocardial infarction and unstable angina remain major causes of morbidity and mortality in patients with atherosclerotic coronary artery disease. Judicious use of cardiac catheterization and coronary revascularization may further improve the prognosis of patients with these acute coronary syndromes (ACS). Patients with ACS at high risk for further cardiac events include those patients with electrocardiographic ST-segment depression, left bundle branch block, and, to a lesser extent, T-wave inversion, and those patients with recurrent pain, cardiac enzyme elevation, or exercise-induced ischemia after hospitalization. While these patient subgroups may benefit from early cardiac catheterization and revascularization, the role of routine coronary revascularization is less well established. Whereas one study has demonstrated reduced recurrent hospitalizations in patients treated with routine invasiveive strategy, another has suggested that outcomes are not different with the two approaches. Pending the results of a third ongoing study Ñ the Thrombolysis in Myocardial Infarction (TIMI)-18 trial Ñ a judicious approach to revascularization in patients presenting with ACS is warranted.

Angiographic and clinical outcomes after rescue coronary stenting.

The role of coronary stenting in improving outcomes after failed thrombolysis has not been well described. This study represents a registry of rescue coronary interventions performed during a 3 year period in which interventional treatment was changing for this high risk population. We analyzed acute angiographic results and clinical outcomes in 108 consecutive patients treated for thrombolytic failure with either balloon angioplasty (n = 63) or coronary stenting (n = 45). The overall in-hospital mortality rate was 5.5%, and there was no increase in complications in the stent group. Coronary stenting was associated with improved angiographic results including lower residual stenosis in the culprit artery (15 +/- 10% vs. 31 +/- 22%, P < 0.001) without increasing bleeding complications. The rate of in-hospital and long term target vessel revascularization in the stent group was significantly lower than in the unmatched PTCA group. Rescue coronary stenting is safe, improves acute angiographic results compared to PTCA alone and leads to excellent in-hospital and long term outcomes.