Comparison of ST-segment resolution influencing in hospital outcome after primary percutaneous coronary intervention and fibrinolysis ( with streptokinase ) in patients with acute ST-segment elevation myocardial infarction

Background: Coronary artery disease (CAD) is the most common cause of mortality & morbidity in all over the world. Reperfusion therapy is the cornerstone for treating acute STsegment elevation myocardial infarction. Effective reperfusion in STEMI can be achieved by either fibrinolysis or primary percutaneous coronary intervention (PPCI). PPCI generally produces better outcomes than fibrinolysis but is not widely available. ST-segment abnormalities play a fundamental role in assessment and decision making for patients with STEMI. Methods: This quasi-experimental study was conducted in the Department of Cardiology, National Heart Foundation Hospital and Research Institute. Group I underwent primary PCI and group II received fibrinolytic therapy as reperfusion therapy for acute STEMI. Results: The mean ST-segment resolutions were significantly more in group I than group II at 60 minutes (63.54±20.98 vs 33.97±15.88%, p<0.001) and at 90 minutes (73.15±18.76 vs 60.06 ±23.33%, p<0.015). However, the difference is not significant at 180 minutes after procedure (74.48±18.09 vs 65.33±21.20%, p=0.064). In our study we observed that significantly higher number of patients of group II developed acute LVF (33.3% vs 6.1%, p=0.005) and cardiogenic shock (18.2% vs 3.0%, p=0.046) than group I and Rescue PCI was needed in 5 (15.2%% vs 0%, p=0.020) patients of group II than group I. Conclusion: ST-segment resolution occurs earlier and more completely after Primary percutaneous coronary intervention than fibrinolysis (with Streptokinase) with better in hospital outcome in patients with acute STEMI.


Introduction
Coronary artery disease (CAD) is the most common cause of mortality & morbidity in all over the world.It is the leading cause of death in developed countries and second leading cause of death in developing countries and by the year 2020 ischemic heart disease (IHD) will hold the first place in the WHO's list of leading cause of disability 1 .Reperfusion therapy is the cornerstone for treating acute STEMI 2 .Effective reperfusion in STEMI can be achieved by either fibrinolytic therapy or primary Percutaneous coronary intervention (PCI) without antecedent fibrinolysis (also generally known as primary angioplasty) 3 .Fibrinolysis and PCI may also be combined in a variety of ways, depending on the timing of PCI after fibrinolytic administration, the clinical condition of the patient, and whether PCI is applied routinely or selectively after lytic therapy.Randomized trials have collectively demonstrated enhanced survival and freedom from major adverse cardiovascular events with primary PCI compared with fibrinolysis, and as a result, the expeditious performance of primary PCI has become the preferred reperfusion modality for patients with STEMI presenting at appropriately equipped centers 3 .Primary Percutaneous coronary intervention generally produces better outcomes than fibrinolysis but is not widely available.Compared to fibrinolysis, PCI more frequently opens infarct arteries, and an "open artery" may provide benefit independent of myocardial salvage, the latter being associated with ST resolution.With fibrinolysis, successfully recanalized infarct arteries (often with ST resolution) are more prone to reocclusion with reinfarctions, as compared to PCI 2 .Simple and rapid measures are needed for timely assessment of the quality of reperfusion therapy in acute STEMI.Although successful recanalization of the epicardial vessel is a necessary condition, it is the microvascular flow that most strongly correlates with outcome.ST-segment changes reflect myocardial rather than epicardial flow and hence yield prognostic information beyond that provided by coronary angiogram alone 4 .The current theory holds that ST-segment resolution or recovery after reperfusion therapy signifies effective microvascular perfusion, myocardial tissue perfusion and myocardial salvage 5 .

Table I .
Distribution and comparison of patients by cardiovascular risk factors (n=66)

Table II .
Comparison of ST-segment resolution between group I and II at 60, 90 and 180 minutes after procedure (n=66)

Table III . Comparison of postprocedural ST segment resolu- tion status between two groups (n=66)
The difference in ECG finding between two groups was not significant (p=0.059).The mean ST-segment resolutions were significantly more in group I than group II at 60 minutes (63.54±20.98vs 33.97±15.88%,p<0.001) and at 90 minutes (73.15±18.76vs 60.06±23.33%,p<0.015).However the difference is not significant at 180 minutes after procedure (74.48±18.09vs 65.33±21.20%,p=0.064).The complete resolution of ST segment occurred significantly and 51.96±8.76years.In the present study, there were 87.9% male in group I and 93.9% in group II.During admission the most frequent complaints of group I and II patients was chest pain (84.8% vs 75.8%) and chest discomfort (15.2% vs 24.2%) with a mean duration of 5.06±2.72 and 4.77±2.54hours respectively.ST elevation was found in leads II, III, aVF in 20(60.6%)patients of group I and 14 (42.4%)patients of group II, in leads V1-V3 in 2 (6.1%) patients of both the groups, in leads V1-V4 in 2(6.1%) patients in group I and 11 (33.3%) in group II, in leads V1-V5 in 3(9.1%) patients in group I and 4 (12.1%) in group II, in leads V1-V6 in 3 (9.1%)patients in group I and none (0%) in group II and in leads V1-V6, I, aVL in 3 (9.1%)patients in group I and 2 (6.1%) in group II.

Table IV .
6istribution and comparison of adverse outcome after 60, 90 and 120 minutes of procedure between two groups (n=66) 2%) vs 9.1%, p=0.451) and death (3.0% vs 6.1%, p=0.555).This observation was supported by the study of Falsoleiman, et al6.ST-segment resolution occurs earlier and more completely after Primary percutaneous coronary intervention than fibrinolysis (with Streptokinase) with better in hospital outcome in patients with acute ST-segment elevation myocardial infarction.The mean ST-segment resolutions were significantly more in group I than group II at 60, and 90 minute after the procedure.The complete resolution of ST segment occurred significantly more in group I than group II at 60 and 90 minute after the procedure.Although the complete resolution of ST segment occurred similarly in group I than group II at 180 minutes after the procedure.Significantly higher number of patients of group II developed acute LVF and cardiogenic shock and needed more rescue PCI than group I.No significant difference was observed between two groups in the development of bleeding from any site, renal failure and death.
Conflict of interest: None