TIMI flow and surrogate end points: what you see is not always what you get

Factors Associated With Normal Flow (TIMI 3) After Thrombolysis With Streptokinase in ST-Elevation Myocardial Infarction: A Prospective Observational Study

Background

Thrombolysis with streptokinase (STK) is the most widely used reperfusion strategy for ST elevation myocardial infarction (STEMI) in India. Achieving full reperfusion as evidenced by thrombolysis in myocardial infarction (TIMI) flow grade 3 in coronary angiography (CAG) is associated with better outcomes. Recent studies show that hematological indices like neutrophil-lymphocyte ratio (NLR) and mean platelet volume (MPV) estimated before thrombolysis could predict TIMI 3 flow. We studied clinical, electrocardiographic and hematological parameters associated with TIMI 3 flow after thrombolysis with STK.

Methods

We prospectively studied 201 adult patients with STEMI presenting within 12 hours of onset of chest pain. Before thrombolysis, blood sample was collected for estimating NLR and MPV. Timing of CAG after thrombolysis was decided by consultant cardiologists. Patients were followed up for one month after discharge.

Results

Of 201 patients, 162 (81%) had relief of chest pain and 131 (65%) had ST segment recovery of ≥50% at 90 minutes after thrombolysis. CAG was performed within median (IQR) of four (3-5) days after thrombolysis. TIMI 3 flow was observed in 112 (56%) patients. NLR and MPV had no significant association with TIMI 3 flow. In multivariable analysis, ST-segment recovery of ≥50% at 90 minutes was associated with TIMI 3 flow (adjusted OR 3.47, 95% CI: 1.84-6.53, P= <0.001). Of 198 patients followed up for one month after discharge, 13 (6.5%) died.

Conclusions

In patients with STEMI, ST-segment recovery of ≥50% at 90 minutes after thrombolysis with STK predicted TIMI 3 flow independently. NLR and MPV values were not predictive of TIMI 3 flow.

Impact of runoff grade after endovascular therapy for femoropopliteal lesions

BACKGROUND

We conceived a new method, runoff grade, to evaluate runoff after endovascular therapy (EVT). We evaluated the validity of using runoff score based on angiographic findings.

METHODS

The subjects were 859 consecutive patients (males, 69%; mean age, 73.0 ± 9.0 years) who underwent EVT for de novo femoropopliteal lesions at Kokura Memorial Hospital. We evaluated the postprocedural tibial runoff, named it runoff grade, classified it into 0 through 2, and retrospectively assessed the relationship with the outcome of EVT. Primary, secondary, and assisted primary patency rates and freedom from major adverse limb events (MALE) were compared between runoff grades.

RESULTS

The mean follow-up period was 31 ± 25 months. The lesion length was 91.5 ± 83.0 mm. The rate of stent use was 52.0%. The primary patency rates at 1, 2, and 3 years were 68.1%, 59.1%, and 53.9%; the secondary patency rates were 90.9%, 88.1%, and 85.9%; the assisted primary patency rates were 79.4%, 72.6%, and 68.5%; and freedom from MALE was 72.5%, 64.8%, and 61.0%, respectively. The primary patency rates at 1, 2, and 3 years were significantly lower in the runoff grade 0 group than in the other groups (55.5% vs 66.7% and 75.6%; 35.8% vs 57.6% and 69.2%; 35.8% vs 53.3% and 60.9% for grade 0, 1, 2, respectively; log-rank, P < .0001). Secondary patency rate (78.5% vs 91.8% and 91.8%; 76.3% vs 88.6% and 89.9%; 72.8% vs 86.3% and 88.2%, respectively; P = .015), assisted primary patency rate (67.0% vs 78.5% and 85.1%; 56.9% vs 71.6% and 79.3%; 47.6% vs 68.0% and 74.8%; respectively, P = .0002), and freedom from MALE (60.8% vs 71.2% and 79.4%; 44.3% vs 64.0% and 72.6%; 36.6% vs 60.7% and 68.5%, respectively; P < .0001) were also similar. After adjustment for age, gender, diabetes, hemodialysis, critical limb ischemia, TransAtlantic Inter-Society Consenus II classification, and stent use, runoff grade was an independent predictor of primary patency.

CONCLUSIONS

Vessels with runoff grade 0 had significantly worse cumulative outcomes. Our results suggested that runoff grade seemed to play an important role to keep the primary patency.

[Primary PCI in ST-elevation myocardial infarction: mode of referral and time to PCI]

INTRODUCTION

According to the current guidelines for treatment of ST-elevation myocardial infarction (STEMI), percutaneous coronary intervention (PCI) should be performed within 90 min of first medical contact and total ischemic time should not exceed 120 min. The aim of this study was to analyze compliance with STEMI guidelines in a tertiary PCI center.

METHODS

This was a prospective single-center registry of 223 consecutive STEMI patients referred for primary PCI between 2003 and 2007.

RESULTS

In this population (mean age 60±12 years, 76% male), median total ischemic time was 4h 30 min (<120 min in 4% of patients). The interval with the best performance was first medical contact to first ECG (median 8 min, <10 min in 59% of patients). The worst intervals were symptom onset to first medical contact (median 104 min, <30 min in 6%) and first ECG to PCI (median 140 min, <90 min in 16%). Shorter total ischemic time was associated with better post-PCI TIMI flow, TIMI frame count and ST-segment resolution (p<0.03). The three most common patient origins were two nearby hospitals (A and B) and the pre-hospital emergency system. The pre-hospital group had shorter total ischemic time than patients from hospitals A or B (2h 45 min vs. 4h 44 min and 6h 40 min, respectively, p<0.05), with shorter door-to-balloon time (89 min vs. 147 min and 146 min, respectively, p<0.05).

CONCLUSIONS

In this population, only a small proportion of patients with acute myocardial infarction underwent primary PCI within the recommended time. Patients referred through the pre-hospital emergency system, although a minority, had the best results in terms of early treatment. Compliance with the guidelines translates into better myocardial perfusion achieved through primary PCI.

The effect of pre-hospital glycoprotein IIb-IIIa inhibitors on angiographic outcome in STEMI patients who are candidates for primary PCI

OBJECTIVES

Aim of this study was to assess the effect of early initiation of high bolus dose tirofiban on top of dual antiplatelet therapy on angiographic outcome before and after primary percutaneous coronary intervention (PCI) in ST-elevation myocardial infraction patients.

BACKGROUND

Glycoprotein IIb/IIIa inhibitors are effective inhibitors of platelet aggregation, and have shown to reduce thrombotic complications in patients undergoing PCI.

METHODS

This is a pre-specified angiographic analysis of the On-TIME 2 trial (N = 984) and its open label run-in phase (N = 414). All angiographic parameters, including quantitative coronary angiography (QCA) were performed in an independent angiographic core lab.

RESULTS

Of the 1,398 patients, 709 patients (50.7%) were randomized to pre-hospital tirofiban. An open infarct related vessel (TIMI 2 or 3 flow) at initial angiography was more often present in the tirofiban group as compared to the no tirofiban group (58.3% vs. 49.7%, P = 0.002). Tirofiban also reduced initial thrombus burden (P for trend = 0.035) as well as thrombus grade 5 (46.9% vs. 54.3%, P = 0.016) and showed a trend toward a reduction in large thrombus burden (LTB) (69.4% vs. 74.5%, P = 0.055). After PCI, a trend towards a lower corrected TIMI frame count (cTFC) in the tirofiban group was found. A significant interaction was found with time of initiation of study drug, with highest efficacy of tirofiban when given within 76 min after symptom onset, with a significantly lower cTFC after PCI (21.9 ± 17.6 vs. 23.9 ± 18.5, P = 0.008, P for interaction P = 0.006).

CONCLUSION

In patients undergoing primary PCI, pre-hospital administration of tirofiban reduces initial thrombus burden and improves initial patency of the infarct related vessel before PCI. Initiation of tirofiban seems to be most effective when given very early after the onset of symptoms; however, this finding needs confirmation in other studies.

CLINICAL TRIAL REGISTRATION

The On-TIME 2 trial is registered, at http://isrctn.org, number ISRCTN06195297.

[Prognosis value of thrombin activatable fibrinolysis inhibitor concentration and C1040T polymorphism in acute myocardial infarction treated with fibrinolysis]

OBJECTIVE

To analyze the prognostic value of thrombin activatable fibrinolysis inhibitor (TAFI) and C1040T polymorphism in acute myocardial infarction treated with fibrinolysis. To analyze C1040T polymorphism influence on its plasma level.

DESIGN

An observational, prospective study performed from November 2003 to November 2005 and with a 3 month follow-up.

SETTING

Intensive Medicine Service from a university-affiliated teaching hospital.

PATIENTS

A total of 53 patients with acute myocardial infarction with persistent ST segment elevation treated with the same fibrinolytic therapy. A control group of 53 biologically similar subjects was included.

INTERVENTIONS

None.

MAIN MEASUREMENTS

Baseline characteristics; frequency of wild-type genotype (Thr325Thr) and of those corresponding to the mutation (Thr325LLe and LLe325lle), TAFI levels at 6 h, 34 h and 3 months post-fibrinolysis; ejection fraction; Killip-Kimball; reperfusion; ischemic recurrence; death.

RESULTS

No relationship was found between biological features and TAFI concentration. The latter was significantly higher in infarct patients (p<0.01) and in the mutation group (p<0.01). The homozygotic mutation (Ile325Ile) was significantly higher in infarct patients (p<0.01). Reperfusion was significantly associated with lower body mass index (p=0.02. OR 0.22. 95% CI), ejection fraction (p=0.004. OR 0.91. 95% CI), triglyceride level (p=0.01. OR 1.02. 95% CI) and cholesterol levels (p=0.001. OR=0.84. 95% CI). Mutation was associated to a significant fall in post-fibrinolysis concentration TAFI antigen and functional TAFI (p=0.01) and (p=0.02), and lower frequency of reperfusion. Reperfusion was associated with a significant post-fibrinolysis reduction in the level of TAFI antigen (p=0.02). Recurrence was associated to a significantly higher post-fibrinolysis level (p=0.05. OR=0.84. 95% CI). This was more frequent in mutation. Post-fibrinolysis TAFI antigen concentration was significantly lower in non-recurrence patients (p=0.028. OR=1.03. 95% CI).

CONCLUSIONS

A higher concentration of TAFI is associated to a worse prognosis in reperfusion and recurrence in acute myocardial infarction treated with fibrinolysis. Homozygotic mutation was more frequent in myocardial infarction patients. Wild genotype is associated to a better prognosis. Mutation is associated to a higher expression of TAFI.

Comparison of AngioJet rheolytic thrombectomy before direct infarct artery stenting with direct stenting alone in patients with acute myocardial infarction. The JETSTENT trial

OBJECTIVES

The aim of this study was to determine whether rheolytic thrombectomy (RT) before direct infarct artery stenting as compared with direct stenting (DS) alone results in improved myocardial reperfusion and clinical outcome in patients with acute myocardial infarction.

BACKGROUND

The routine removal of thrombus before infarct artery stenting is still a matter of debate.

METHODS

This is a multicenter, international, randomized, 2-arm, prospective study. Eligible patients were patients with acute myocardial infarction, angiographic evidence of thrombus grade 3 to 5, and a reference vessel diameter ≥2.5 mm. Coprimary end points were early ST-segment resolution and (99m)Tc-sestamibi infarct size. An α value = 0.05 achieved by both coprimary surrogate end points or an α value = 0.025 for a single primary surrogate end point would be considered evidence of statistical significance. Other surrogate end points were Thrombolysis In Myocardial Infarction (TIMI) flow grade 3, corrected TIMI frame count, and TIMI grade 3 blush. Clinical end points were a composite of major adverse cardiovascular events at 1, 6, and 12 months.

RESULTS

From December 2005 to September 2009, 501 patients were randomly allocated to RT before DS or to DS alone. The ST-segment resolution was more frequent in the RT arm as compared with the DS alone arm: 85.8% and 78.8%, respectively (p = 0.043), while no difference between groups were revealed in the other surrogate end points. The 6-month major adverse cardiovascular events rate was 11.2% in the thrombectomy arm and 19.4% in the DS alone arm (p = 0.011). The 1-year event-free survival rates were 85.2 ± 2.3% for the RT arm, and 75.0 ± 3.1% for the DS alone arm (p = 0.009).

CONCLUSIONS

Although the primary efficacy end points were not met, the results of this study support the use of RT before infarct artery stenting in patients with acute myocardial infarction and evidence of coronary thrombus. (AngioJet Rheolytic Thrombectomy Before Direct Infarct Artery Stenting in Patients Undergoing Primary PCI for Acute Myocardial Infarction [JETSTENT]; NCT00275990).

Spontaneous delayed recovery of perfusion after thrombolyzed acute myocardial infarction: is it predictable before discharge?

In patients with thrombolyzed acute myocardial infarction, early assessment of the final infarct size is difficult because spontaneous recovery of perfusion and function of the left ventricle may be delayed. This study was undertaken to evaluate the ability of predischarge low-dose dobutamine echocardiography to predict late spontaneous recovery of perfusion assessed by single-photon emission computed tomography after acute myocardial infarction. We prospectively studied 53 consecutive patients with myocardial infarction treated with thrombolysis. Low-dose dobutamine echocardiography and resting (99m)Tc-sestamibi single-photon emission computed tomography (MIBI SPECT) were performed 4 +/- 2 days after infarction. A follow-up SPECT study was carried out in 45 patients after 6 months. Myocardial recovery was defined as a reduction of SPECT defect size by more than 10% at follow-up compared with the early study. In 25 of the 45 patients, the size of the left ventricular perfusion defect decreased significantly from 42% +/- 16% to 27% +/- 10% (group 1), whereas in the remaining 20 patients it showed no significant change (group 2). Predischarge low-dose dobutamine echocardiography showed a significant improvement in wall motion score index compared with baseline in group 1, from 1.62 +/- 0.28 to 1.41 +/- 0.24, P <.001, whereas in group 2 this index remained without significant change. Predischarge low-dose dobutamine echocardiography is an accurate tool for prediction of late recovery of myocardial perfusion after acute myocardial infarction treated with thrombolysis.

Achieving tissue-level perfusion in the setting of acute myocardial infarction

Treatment for ST-elevation myocardial infarction (MI) has advanced rapidly in the last few years with improvements in early fibrinolytic therapy, primary percutaneous revascularization, and use of potent platelet glycoprotein IIb/IIIa inhibitors. It is now obvious that establishing epicardial patency after myocardial infarction is not synonymous with tissue-level perfusion. Techniques and therapies are now available that measure true tissue-level perfusion and that may improve tissue-level perfusion after myocardial infarction.

[Patency, perfusion and prognosis in acute myocardial infarct]

Early restoration of bloodflow in the infarct-related coronary artery is the principal mechanism by which early reperfusion therapies may improve outcome in patients with acute myocardial infarction. The beneficial effect of reperfusion is independent of the therapy used (thrombolysis or PTCA), but, as shown in many studies, depends very much on the time to reperfusion. The achievement of a normal bloodflow in the infarct vessel, the so called TIMI 3 patency is considered to be the gold standard for the evaluation of the success of reperfusion therapy. However, there is increasing evidence from recent studies, that restoration of epicardial bloodflow does not necessarily indicate perfusion at the myocardial level. As unequivocally shown by contrast echocardiography using intracoronary injections of microbubbles, this is true even for TIMI Grade 3 flow, which correlates most strongly with prognosis and usually is associated with a very low mortality of about 3 to 4%. Angiographic patency not only is a sometimes unreliable indicator of myocardial reperfusion, but also involves an invasive procedure, is expensive and not universally available. A readily available and simple indicator of reperfusion is the early resolution of ST segment elevation. Complete ST resolution at 90 or 180 minutes after the initiation of treatment is associated with an excellent prognosis, even better than TIMI 3 patency. In contrast, no ST resolution indicates an in-hospital mortality which is about 8-fold greater than with complete ST resolution. Since ST resolution may be more closely related with the relief of ischemia than angiographic patency, the prognostic power of the combination of both indicators should be greater than that of either of them alone. Thus, it is evident from many studies that patency of the infarct-related artery is necessary for myocardial salvage in acute myocardial infarction, but it has to be achieved rapidly and has to be complete and sustained. However, even an early and perfect angiographic result achieved by thrombolysis or PTCA, does not consistently indicate myocardial reperfusion, and the mechanisms of the often called no-reflow phenomenon are still poorly understood. The possible contribution of reperfusion injury to poor clinical outcomes after adequate epicardial flow has been restored is also a matter of controversy and deserves further research. Promising results were derived from studies with GP IIb/IIIa inhibitors, in which improved microvascular flow and myocardial reperfusion were observed, when these agents were used as adjunct to thrombolysis and PTCA.