Does thrombolysis in myocardial infarction (TIMI) perfusion grade 2 represent a mostly patent artery or a mostly occluded artery? Enzymatic and electrocardiographic evidence from the TEAM-2 study

Abstract

One measure of the success of thrombolysis is the early patency status of the infarct-related coronary artery. The Thrombolysis in Myocardial Infarction (TIMI) study group designated patency grades 0 (occluded) or 1 (minimal perfusion) as thrombolysis failure and grade 2 (partial perfusion) or 3 (complete perfusion) as success. To evaluate their true functional significance, perfusion grades were compared with enzymatic and electrocardiographic (ECG) indexes of myocardial infarction in 359 patients treated within 4 h with anistreplase (APSAC) or streptokinase. Serum enzymes and ECGs were assessed serially. Patency was determined at 90 to 240 min (median 2.1 h) and graded by an observer who had no knowledge of patient data. Results for the two drug arms were similar and combined. Distribution of patency was grade 0 = 20%, n = 72; grade 1 = 8% n = 27; grade 2 = 16%, n = 58 and grade 3 = 56%, n = 202. Interventions were performed after angiography but within 24 h in 51% (n = 37), 70% (n = 19), 41% (n = 24) and 14% (n = 28) of patients with grades 0, 1, 2 and 3, respectively. Outcomes were compared among the four patency groups by the orthogonal contrast method. Patients with perfusion grade 2 did not differ significantly from those with grade 0 or 1 in enzymatic peaks, time to peak activity and evolution of summed ST segments, Q waves and R waves (contrast 2). Conversely, comparisons of patients with grade 3 perfusion with those with grades 0 to 2 yielded significant differences for enzymatic peaks and time to peak activity for three of the four enzymes (p = 0.02 to 0.0001) and ECG indexes of myocardial infarction (p = 0.02 to 0.0001) (contrast 3). Thus, patients with grade 2 flow have indexes of myocardial infarction similar to those in patients with an occluded artery (grades 0 and 1 flow). Only early grade 3 flow results in a significantly better outcome than that of the other grades. Because early achievement of grade 2 flow does not appear to lead to optimal myocardial salvage, the frequency of achieving grade 3 perfusion alone may best measure the reperfusion success of thrombolytic therapy.

Relationship of TIMI Myocardial Perfusion Grade to Mortality After Administration of Thrombolytic Drugs

“…Improved epicardial blood flow assessed by use of either TIMI flow grades [1][2][3][4][5][6] or the TIMI frame count 7,8 has been related to reduced mortality after thrombolytic administration. The data presented here indicate that improved myocardial perfusion at 90 minutes after thrombolytic administration is related to reduced mortality independent of epicardial blood flow.…”

“…W hereas improved epicardial blood flow (as assessed with either TIMI flow grades [1][2][3][4][5][6] or the TIMI frame count 7,8 ) has been related to reduced mortality after administration of thrombolytic drugs, the relationship between tissue-level microvascular perfusion and mortality has not been examined in a large number of patients after thrombolytic administration. This study describes the development and use of a simple semiquantitative classification scheme, the TIMI myocardial perfusion grade (TMP), that can be used to characterize the filling and clearance of myocardial perfusion from a coronary angiogram.…”

Post-procedural TIMI flow grade 2 is not associated with improved prognosis in patients with non-ST-segment elevation myocardial infarction undergoing percutaneous coronary revascularization (PL-ACS registry)

“…Only post-procedural Thrombolysis in Myocardial Infarction (TIMI) flow grade 3 improves outcomes in patients with STEMI. Although it was shown that prognosis in patients with final TIMI flow grade 2 does not differ from that in patients with TIMI flow grade 0-1, this conclusion was based on the results of outdated studies involving acute myocardial infarction (AMI) patients treated with thrombolytic therapy [5][6][7]. Thus, there is a paucity of data on the association between angiographic findings and clinical outcomes in patients with myocardial infarction (MI) without ST-segment elevation undergoing percutaneous coronary intervention (PCI).…”

Coronary and Myocardial Angiography

“…It has been a valuable tool to compare angiographic outcomes following reperfusion, and the association of the TFGs with clinical outcomes (including mortality) has been well documented. [2][3][4][5][6][7][8] The relationship between TFG and mortality does satisfy what some consider to be 3 criteria required to validate a surrogate end point for mortality, as follows: (1) There is an association between TIMI grade 3 flow and mortality, (2) an agent such as recombinant tissue plasminogen activator improves TIMI grade 3 flow by 22% over another agent such as streptokinase, and (3) the agent tissue plasminogen activator improves mortality 1.1% over streptokinase.…”

“…[1][2][3][4][5][6][7][8] It has become increasingly apparent, however, that clinical outcomes are not only associated with angiographic flow in the epicardial artery, but also with angiographic flow in the myocardium. 9 -13 To this end, the goal of reperfusion therapies has shifted to include reperfusion downstream at the level of capillary bed, and it might be more appropriate that the hypothesis now be termed "the time dependent open artery and open microvascular hypothesis."…”