Predictors of stent thrombosis after primary stenting for acute myocardial infarction

The Effect of Diabetes on Prognosis Following Myocardial Infarction Treated with Primary Angioplasty and Potent Antiplatelet Therapy

PURPOSE

To investigate the prognostic significance of diabetes mellitus (DM) in patients with high risk acute myocardial infarction (AMI) treated with primary percutaneous coronary intervention (pPCI) in the era of potent antithrombotics.

METHODS

Data from 1230 ST-segment elevation myocardial infarction (STEMI) patients enrolled in the PRAGUE-18 (prasugrel vs. ticagrelor in pPCI) study were analyzed. Ischemic and bleeding event rates were calculated for patients with and without diabetes. The independent impact of diabetes on outcomes was evaluated after adjustment for outcome predictors.

RESULTS

The prevalence of DM was 20% (N = 250). Diabetics were older and more often female. They were more likely to have hypertension, hyperlipoproteinemia, multivessel coronary disease and left main disease, and be obese. The primary net-clinical endpoint (EP) containing death, spontaneous nonfatal MI, stroke, severe bleeding, and revascularization at day 7 occurred in 6.1% of patients with, and in 3.5% of patients without DM (HR 1.8; 95% CI 0.978-3.315; P = 0.055). At one year, the key secondary endpoint defined as cardiovascular death, spontaneous MI, or stroke occurred in 8.8% with, and 5.5% without DM (HR 1.621; 95% CI 0.987-2.661; P = 0.054). In those with DM the risk of total one-year mortality (6.8% vs. 3.9% (HR 1.773; 95% CI 1.001-3.141; P = 0.047)) and the risk of nonfatal reinfarction (4.8% vs. 2.2% (HR 2.177; 95% CI 1.077-4.398; P = 0.026)) were significantly higher compared to in those without DM. There was no risk of major bleeding associated with DM (HR 0.861; 95% CI 0.554-1.339; P = 0.506). In the multivariate analysis, diabetes was independently associated with the one-year risk of reinfarction (HR 2.176; 95% Confidence Interval, 1.055-4.489; p = 0.035).

CONCLUSION

Despite best practices STEMI treatment, diabetes is still associated with significantly worse prognoses, which highlights the importance of further improvements in the management of this high-risk population.

[Decreasing incidence of stent thrombosis]

Stent thrombosis (ST) remains a major pitfall of stent implantation in contemporary percutaneous coronary intervention (PCI) leading to high rates of death and non-fatal myocardial infarction. Many predictors of ST have been reported worldwide but the strongest have to be highlighted regarding the catastrophic prognosis of such an event. Because platelet aggregation has a pivotal role in ST pathogenesis, the new antiplatelet regimens combining aspirin and P2Y12 receptor inhibitors have led to a remarkable decrease in the ST incidence, especially in the setting of acute coronary syndrome (ACS). In this article, our purpose is to review the evolution of ST incidence since first stent use in PCI. We will also overview the main predictors of ST focusing on ACS and clopidogrel low response.

Clinical features of early recurrent myocardial infarction

Recurrence of myocardial infarction, especially when occurring early after the prior one, carries a significant morbidity and mortality rate. The aim of this study was to investigate the characteristics of patients who experienced recurrence under secondary prevention therapy. Case record review identified myocardial infarction patients who had a history of previous myocardial infarction within 5 years. Hospital chart records, initial laboratory data, medications, and type of infarction were reviewed. Patients were divided into two groups according to the interval of recurrence: an early group (recurrence within 1 year), and a late group (recurrence after more than 1 year). A total of 89 patients were included in the analysis; 40 patients in the early group, and 49 patients in the late group. Mean age in the early group and late groups was 67.3 +/- 11.9 and 59.4 +/- 8.9, respectively (P = 0.001). Mean body mass index in the early and late groups was 22.1 +/- 3.6 and 25.0 +/- 3.3, respectively (P < 0.001). There were fewer current smokers in the early group (7.5% vs 44.9%, P < 0.001) and more stent thrombosis (17.5% vs 2%, P = 0.02), as compared with the late group. The in-hospital mortality rate tended to be higher in the early group (7.5% vs 0%, P = 0.09). Multiple logistic regression revealed that smoking status (odds ratio [OR] 0.09, 95% confidence interval [CI] 0.02-0.49, P = 0.005), HDL cholesterol level (5 mg/dl increase: OR 1.34, 95% CI 1.04-1.74, P = 0.03), and stent thrombosis (OR 35.59, 95% CI 2.13-595.49, P = 0.01) had significant associations with early recurrence. Early recurrence of myocardial infarction was associated with stent thrombosis, a higher HDL cholesterol level, and a lower frequency of smoking. Early recurrence had a trend toward higher mortality than late recurrence.

An Internet-based registry examining the efficacy of heparin coating in patients undergoing coronary stent implantation

BACKGROUND

Heparin coating is an attractive alternative to counterbalance intrinsic stent thrombogenicity and to decrease the incidence of stent thrombosis.

METHODS

We compared, based on the data of an international multicenter prospective registry, the rates of stent thrombosis after percutaneous coronary interventions in native coronary arteries using a Bx VELOCITY heparin-coated stent versus a bare metal stent of the same design in a total of 3098 patients at high risk for stent thrombosis. Most patients in both groups underwent percutaneous coronary intervention for unstable angina (48.4% vs 47.5%, respectively) with > 25% of the patients treated for acute myocardial infarction (30.8% and 28.1%, respectively).

RESULTS

Procedural success was high and very similar in patients with heparin-coated and bare metal stents (99.3% vs 98.8%, respectively, P = .11). The primary end point, a 30-day stent thrombosis, occurred in 0.6% of the 1417 patients treated with the heparin-coated stent and 0.9% of the 1681 patients treated with the bare metal stent (relative risk reduction 33%, P = .41). The rates of cardiac death, myocardial infarction, and target lesion revascularization did not differ significantly between the groups. By multivariate analysis, variables independently associated with 30-day stent thrombosis included the evidence of thrombus at baseline (odds ratio [OR] 3.0, 95% CI 1.29-7.0, P = .01), small vessel stenting (OR 2.41, 95% CI 1.01-5.74, P = .05), and target left anterior descending artery (OR 2.32, 95% CI 1.00-5.38, P = .05).

CONCLUSION

This large-scale registry comparing the use of heparin-coated stent versus bare metal stent in the reality of daily practice showed no significant difference in stent thrombosis in patients with a high-risk profile for thrombotic complications.

Stent thrombosis following bare-metal stent implantation: success of emergency percutaneous coronary intervention and predictors of adverse outcome

AIMS

To investigate the efficacy and outcome of emergency percutaneous coronary interventions (PCI) in patients with stent thrombosis.

METHODS AND RESULTS

Between 1995 and 2003, 6058 patients underwent bare-metal stent implantation, of which 95 (1.6%) patients suffered from stent thrombosis. The timing of stent thrombosis was acute in 10 (11%), subacute in 61 (64%), and late in 24 (25%) patients. Procedural and clinical outcomes of emergency PCI for treatment of stent thrombosis were investigated. Emergency PCI was successful in 86 (91%), complicated by death in 2 (2%), and coronary artery bypass grafting in 2 (2%) patients. Myocardial infarction occurred in 77 (81%) patients with a peak creatine kinase level of 1466+/-1570 U/L. Left ventricular ejection fraction declined from 0.54+/-0.19 prior to 0.48+/-0.16 (P<0.05) at the time of stent thrombosis after emergency PCI. A 6 month major adverse clinical events comprised death (11%), reinfarction (16%), and recurrent stent thrombosis (12%) after emergency PCI. Multivariable logistic regression analysis identified the achievement of TIMI 3 flow (OR=0.1, CI 95% 0.01-0.54, P<0.001) and diameter stenosis <50% (OR=0.06, CI 95% 0.01-0.32, P<0.001) during emergency PCI to be independently associated with a reduced risk of cardiac death. Recurrent stent thrombosis was independently predicted by the omission of abciximab (OR=4.3, CI 95% 1.1-17.5).

CONCLUSION

Emergency PCI for treatment of stent thrombosis effectively restores vessel patency and flow. Patients presenting with stent thrombosis are at risk for recurrent myocardial infarction and recurrent stent thrombosis.

Acute coronary syndromes and diabetes mellitus

Patients with diabetes mellitus who present with acute ST-segment elevation myocardial infarction or non-ST-segment elevation acute coronary syndromes have a higher risk of adverse outcomes than patients without diabetes, and appear to derive greater benefit from evidence-based therapies. However, patients with diabetes mellitus are less commonly treated with proven therapies, so renewed efforts are needed to improve the quality of care and outcomes for patients with diabetes mellitus who present with acute coronary syndromes.

New bifurcation stenting technique: Shunt stenting

The optimal treatment of bifurcation lesions remains controversial. We describe a new technique we term shunt stenting. This technique incorporates both the new technology of drug-eluting stents and a novel procedure for optimizing the ostial side branch stent positioning. To date, early angiographic and clinical follow-up have been encouraging.

[Coronary angioplasty in diabetic patients. Current and future perspectives]

It has been estimated that 15-25% of patients who undergo percutaneous or surgical coronary angioplasty are diabetics. The indications for coronary revascularization and initial results of the procedure do not differ substantially between patients with diabetes mellitus and non-diabetics. However, the long-term results of both percutaneous and surgical coronary angioplasty are less favorable in diabetics in terms of mortality and the need for new revascularization procedures. The development and widespread use of stents and glycoprotein IIb/IIIa receptor inhibiting drugs have improved the clinical evolution of diabetics treated with angioplasty. Currently available data show that the administration of glycoprotein IIb/IIIa inhibitors to patients undergoing coronary angioplasty is especially useful in diabetics and improves short-term and long-term results, decreasing one-year mortality by 45%. There seem to be indications for the routine use of glycoprotein IIb/IIIa inhibitors in diabetics treated with angioplasty. While the use of stents has improved long-term and short-term results in diabetics, the success rates of angioplasty in diabetics are still lower than in non-diabetics. Diabetes is still an independent predictor of restenosis and long-term events after stenting interventions. Analysis of the studies comparing percutaneous and surgical revascularization in diabetic patients with multivessel disease shows that surgery is superior in terms of long-term mortality and need for new revascularization procedures. Stenting has improved, but not substantially, the results of multivessel angioplasty in diabetics. Therefore, the indications for angioplasty in multivessel diabetics should be evaluated individually. Factors that contribute to the less favorable post-angioplasty evolution of diabetic patients are more rapid progression of atherosclerosis and, especially, a higher rate of restenosis. New angioplasty techniques, such as brachytherapy and drug-eluting stents, are likely to significantly improve the results of percutaneous interventions in diabetics, thus allowing the indications for angioplasty in diabetics to be extended even further in the near future.

Rheolytic thrombectomy for in-stent thrombosis: creating a diagnostic window

Acute-stent thrombosis is a relatively uncommon complication of coronary artery stenting, however, it is a potentially catastrophic event. In this case report of stent thrombosis, rheolytic thrombectomy is used to reestablished flow within the artery and, thereby, facilitate intravascular ultrasound. This documented that inadequate stent expansion, residual disease, and tissue prolapse through the stent at an angulated segment of the artery are factors that may underlie thrombosis. This case illustrates that rheolytic thrombectomy is feasible in subacute thrombosis, and that this approach facilitates diagnostic evaluation and treatment of underlying factors involved in stent thrombosis.