Antiplatelet agents and their effect on complications during or soon after percutaneous transluminal coronary angioplasty

Triflusal

Triflusal (Aflen, Disgren, Tecnosal, Triflux) is a novel platelet antiaggregant with structural similarities to salicylates, but which is not derived from aspirin. It has similar efficacy to aspirin in patients with cerebral or myocardial infarction, but has a reduced risk of haemorrhagic complications. In addition, triflusal plus moderate-intensity anticoagulation has demonstrated efficacy when used as thromboprophylaxis in atrial fibrillation. As such, triflusal has a role in the primary prevention of cerebrovascular events in atrial fibrillation, and for the secondary prevention of cerebral and myocardial infarction, primarily as an alternative to aspirin in patients for whom aspirin is unsuitable.

Triflusal for preventing serious vascular events in people at high risk

BACKGROUND

Aspirin is the standard treatment for secondary prevention of stroke and other vascular events. Several studies suggest that triflusal may have a better safety profile.

OBJECTIVES

To determine in people at high risk of vascular events whether triflusal is an effective and safe treatment for primary and secondary prevention of serious vascular events.

SEARCH STRATEGY

We searched the trials registers of the following Cochrane Review Groups: Stroke Group (last searched October 2004), Heart Group, Peripheral Vascular Diseases Group and Metabolic and Endocrine Disorders Group (last searched May 2003). In addition, we searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2003), MEDLINE (1977 to 2003) and EMBASE (1980 to 2003). We searched reference lists and contacted researchers in the field, authors of relevant trials and the drug manufacturer.

SELECTION CRITERIA

Randomised and quasi-randomised studies comparing triflusal with placebo or aspirin in people at high risk of vascular events.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. The primary outcome was a serious vascular event (non-fatal acute myocardial infarction (AMI), non-fatal ischemic or hemorrhagic stroke, or vascular death). Other efficacy and safety measures collected were frequency of different vascular events, adverse events, minor and major hemorrhages.

MAIN RESULTS

(1) Aspirin versus triflusal: five studies enrolled patients with stroke or transient ischemic attack (TIA) (4 trials; 2944 patients; followed for 6 to 47 months) or AMI (one trial; 2275 patients; followed for 35 days). Entry criteria were similar within each subgroup of patients. Patient groups were appropriately selected and well matched. The primary outcome in all trials was a composite outcome of vascular events. Trials had no important bias except in one study (217 patients). For the primary outcome of a serious vascular event there was no significant difference between triflusal and aspirin; the odds ratio (OR) was 1.04 (95% confidence interval (CI) 0.87 to 1.23). Significant differences were found for frequency of hemorrhages, both minor (OR 1.60, 95% CI 1.31 to 1.95) and major (OR 2.34, 95% CI 1.58 to 3.46) and for non-hemorrhagic gastrointestinal adverse events (OR 0.84, 95% CI 0.75 to 0.95). Sensitivity analysis of well versus poorly allocated trials showed no significant differences. (2) Triflusal versus placebo: two trials enrolled patients with unstable angina (281 patients) or peripheral arteriopathy (122 patients), who were followed for 6 months. Triflusal was associated with a reduction in serious vascular events (OR 2.29, 95% CI 1.01 to 5.19; OR greater than 1 favours triflusal) and with a higher frequency of adverse events (OR 1.68, 95% CI 1.00 to 2.80).

AUTHORS' CONCLUSIONS

No significant differences were found between triflusal and aspirin for secondary prevention of serious vascular events in patients with stroke or TIA and AMI. However, our review cannot exclude moderate differences in efficacy. Triflusal was associated with a lower risk of hemorrhagic complications.

Triflusal vs aspirin for prevention of cerebral infarction

BACKGROUND

Triflusal is an antiplatelet agent that has shown clinical advantages when compared with aspirin in the secondary prevention of vascular events. TAPIRSS (Triflusal versus Aspirin for Prevention of Infarction: a Randomized Stroke Study) explored the efficacy and safety of triflusal in the secondary prevention of stroke in a Latin American homogeneous population with the ultimate aim of preparing for a larger trial in the same setting.

METHODS

A double-blind, multicenter, randomized, pilot trial was conducted in Buenos Aires, Argentina, from October 1996 to November 1999. The study sample was 431 patients, randomized to receive aspirin 325 mg daily or triflusal 600 mg daily for a mean of 586 days. All patients had experienced either an ischemic stroke or TIA within 6 months from enrollment. Data from 429 patients were analyzed.

RESULTS

No differences were observed in the primary endpoint that combined the incidence of vascular death, cerebral ischemic infarction, nonfatal myocardial infarction, or major hemorrhage (aspirin 13.9%, triflusal 12.7%; odds ratio [OR] 1.11, 95% CI 0.64 to 1.94) or in the individual analysis of each component of the primary endpoint. In a post hoc analysis, the overall incidence of major and minor hemorrhagic events was significantly lower in triflusal-treated patients (aspirin 8.3%, triflusal 2.8%; OR 3.13, 95% CI 1.22 to 8.06).

CONCLUSIONS

This pilot trial has not found differences between triflusal and aspirin in the prevention of vascular complications after TIA or ischemic stroke, although given the wide CI, potentially important group differences could not be ruled out. Triflusal may be associated with a lower risk of hemorrhagic complications. A larger, prospective clinical trial is necessary to verify these results.

Comparison of triflusal and aspirin for prevention of vascular events in patients after cerebral infarction: the TACIP Study: a randomized, double-blind, multicenter trial

BACKGROUND AND PURPOSE

The efficacy of the antiplatelet agent triflusal for prevention of vascular events after stroke has been reported in a pilot study. However, there is a need to confirm those results in a larger study.

METHODS

We performed a randomized, double-blind, multicenter study to test the efficacy of triflusal (600 mg/d) versus aspirin (325 mg/d) for prevention of vascular events in patients with stroke or transient ischemic attack (Triflusal versus Aspirin in Cerebral Infarction Prevention [TACIP]). We assessed a combined end point (incidence of nonfatal ischemic stroke, nonfatal acute myocardial infarction, or vascular death) as well as the incidence of these events separately and the incidence of major hemorrhage.

RESULTS

Of 2113 patients, 1058 received triflusal and 1055 aspirin. The mean follow-up period was 30.1 months. The incidence of combined end point (13.1% for triflusal, 12.4% for aspirin) as well the survival analysis (hazard ratio [HR] for triflusal versus aspirin, 1.09; 95% CI, 0.85 to 1.38) showed no differences between groups. The incidence of nonfatal stroke (HR, 1.09; 95% CI, 0.82 to 1.44), nonfatal acute myocardial infarction (HR, 0.95; 95% CI, 0.46 to 1.98,) and vascular death (HR, 1.22; 95% CI, 0.75 to 1.96) was also similar. A significantly higher incidence of major hemorrhages in the aspirin group was recorded (HR, 0.48; 95% CI, 0.28 to 0.82). The overall incidence of hemorrhage was significantly lower in the triflusal group (16.7% versus 25.2%) (odds ratio, 0.76; 95% CI, 0.67 to 0.86; P<0.001).

CONCLUSIONS

This study failed to show significantly superior efficacy of triflusal over aspirin in the long-term prevention of vascular events after stroke, but triflusal was associated with a significantly lower rate of hemorrhagic complications.

Effect of dipyridamole on vascular responses of porcine ciliary arteries

This study investigated the effects of dipyridamole in isolated porcine ciliary arteries (diameter 200-250 microns). Isolated porcine ciliary arteries were suspended in myograph chambers filled with modified Krebs-Ringer solution (37 degrees C; 95% O2/5% CO2) for isometric tension recording. Dipyridamole induced concentration-dependent relaxations of porcine ciliary arteries with endothelium precontracted with thromboxane analogue U-46619 (10(-6)M), KCl (50 mM), or endothelin-1 (10(-8)M). Removal of the endothelium of the ciliary vessels and preincubation of the arteries with L-NAME (10(-5)M), or indomethacin (10(-5)M), or the combination of the two drugs significantly reduced the relaxation to dipyridamole (p = 0.002-0.03). Similar vascular responses could be observed in a time-dependent analysis of the effect of a single concentration dipyridamole (10(-4)M). The stimulator of cAMP forskolin also caused relaxations. Endothelin-1 (10(-12)-10(-7)M) and U-46619 (10(-10)-10(-6)M) induced potent contractions of porcine ciliary arteries. Preincubation with dipyridamole (10(-5)M) reduced contractions to endothelin-1 as compared to control (p < 0.004), while contractions to U-46619 were only slightly affected under these conditions (n.s.). These findings demonstrate that dipyridamole is a vasodilator in porcine ciliary arteries. Endothelial nitric oxide and prostacyclin contribute importantly to the effects of dipyridamole. Further studies are required to show whether these properties of dipyridamole may also occur in vivo and offer clinical use in patients with ocular vasospasms and other ophthalmic vascular dysfunctions.