Pharmaco-invasive strategy: An attractive alternative for management of ST-elevation myocardial infarction when timely primary percutaneous coronary intervention is not feasible

摘要

ST-elevation myocardial infarction (STEMI) refers to an evolving/completed acute myocardial infarction due to coronary ischemia associated withST elevation (usually due to acute total or subtotal occlusion of an epicardial coronary artery). Timely intervention to revascularize the occludedcoronary artery is the mainstay of treatment for patients with STEMI and should be achieved ideally as soon as possible in all patients presentingwithin 12 h of symptom onset.[1] Benefit from revascularization can extend up to 24 h, especially if there is ongoing evidence of coronary ischemia.[1] The preferred means for reperfusion in STEMI is a primary percutaneous coronary intervention (PPCI), and this is the recommended therapyin all patients, provided it can be performed within 120 min of first medical contact.[1] When PPCI cannot be performed in this time frame,fibrinolysis is recommended within 30 min of arrival to the hospital.[1] There are several barriers to achieving these targets in India. Awarenessabout symptoms related to acute myocardial infarction and regarding the importance of seeking early medical attention is low. Means for timelyand safe transfer (such as in a well-equipped ambulance) to a hospital for PPCI or fibrinolysis are limited in most cases. 24-h PPCI facilities areavailable in a few centers, clustered mostly in larger cities. Access to PPCI is even more restricted in the rural or semi-urban setting. Furthermore,PPCI remains a costly intervention, which is beyond the means of a large percentage of the population. As a result of these factors, PPCI within120 min is often a difficult target to achieve for a large number of patients presenting with STEMI in India. An attractive alternative in this scenario,when PPCI cannot be achieved within 120 min of first medical contact, is pharmaco-invasive strategy, which involves fibrinolysis at the point ofcontact with a nonpercutaneous coronary intervention (PCI) center, followed by transfer to PCI capable center for coronary angiography/PCIwithin 24 h of fibrinolysis. This is a different approach compared to facilitated PCI, where fibrinolysis is administered immediately before PCI, suchas on route to a PCI center. Trials have failed to show a clear benefit from facilitated PCI, and in fact suggest a potential for harm with thisapproach, hence this is not a recommended strategy for reperfusion.[2] As compared with facilitated PCI, the pharmaco-invasive approach targetspatients presenting to a non-PCI center, when PPCI cannot be completed within 120 min. Clinical trials and registry data have shown that clinicaloutcomes with pharmaco-invasive strategy are comparable to the outcomes with PPCI.[2],[3],[4] STREAM study is a well powered multicenterrandomized (open-label) clinical trial, which clearly demonstrated that there was no statistically significant difference in the rate of primarycomposite outcome (death, shock, congestive cardiac failure, or re-infarction at 30 days) between PPCI versus pharmaco-invasive strategy inpatients in whom PPCI could not be achieved within 1 h of presentation. All patients in the study presented within 3 h of symptom onset.[5] Themain clinical adverse outcome to pharmaco-invasive approach in this study was a higher risk of an intracranial bleed in older patients (>75 years ofage) who were treated with full dose thrombolysis with tenecteplase. However, this increased risk of intracranial bleed was no longer observedafter reducing the dose of tenecteplase for age >75 years. In the STREAM trial, the pharmaco-invasive group underwent PCI after transfer toPCI-capable center either emergently, if there was evidence of the failure of thrombolysis, or in 6–24 h after randomization if patients wereclinically stable.[5] There is evidence to suggest that pharmaco-invasive strategy may be an effective treatment option for patients presenting with STEMI in India, where delay in presentation to the hospital from onset of symptoms as well as in completing PPCI from first medical contact iscommon due to factors mentioned above.[6],[7]