Presence of Older Thrombus Is an Independent Predictor of Long-Term Mortality in Patients With ST-Elevation Myocardial Infarction Treated With Thrombus Aspiration During Primary Percutaneous Coronary Intervention

Abstract

Background-Routine thrombus aspiration is frequently used during primary percutaneous coronary intervention in patients with ST-elevation myocardial infarction to prevent distal embolization. Recently, evidence of clinical benefit was published. In 50% of the ST-elevation myocardial infarction patients with an onset of symptoms Ͻ12 hours before, thrombi were shown to be Ͼ1 day old. This observation illustrates that plaque rupture and coronary occlusion are significantly separated in time. In the present study, we correlate the presence of fresh versus older thrombus with long-term mortality. Methods and Results-Thrombus aspiration was performed in 1315 patients treated with primary percutaneous coronary intervention with 3 devices (Rescue, Export, and Proxis). Aspirated material was fixed in formalin and processed for histopathology. If possible, thrombus age was classified as either fresh only (Ͻ1 day) or older (Ͼ1 day). We identified fresh thrombus in 552 patients and older thrombus in 372 patients. The cumulative Kaplan-Meier estimate of all-cause mortality at 4 years was significantly higher in patients with older thrombus (16.0%) compared with patients with fresh thrombus (7.4%), with a hazard ratio of 1.82 (95% confidence interval, 1.17 to 2.85; Pϭ0.008). Multivariate analysis identified the presence of older thrombus, in addition to other established predictors, as an independent predictor (hazard ratio, 1.83; 95% confidence interval, 1.14 to 2.93; Pϭ0.01) of long-term mortality. Conclusion-Our study demonstrates that the presence of older thrombus, in addition to other established predictors, is an independent predictor of long-term mortality in patients with ST-elevation myocardial infarction treated with thrombus aspiration during primary percutaneous coronary intervention.

Thrombus Aspiration Therapy and Coronary Thrombus Components in Patients with Acute ST-Elevation Myocardial Infarction

“…The results of histopathological evaluations of aspirated intracoronary thrombi obtained from STEMI patients have recently been presented [73][74][75][76][77] . Rittersma et al investigated 199 aspirated intracoronary thrombi obtained from STEMI patients within six hours of symptom onset and pathologically classified them into fresh thrombi (＜1 day old) composed of layered patterns of fibrin and intact platelets, erythrocytes and granulocytes and older thrombi with lytic (1 to 5 days) or organized (＞5 days) changes 73) .…”

“…Several recent studies have demonstrated associations between coronary thrombus characteristics and DE/myocardial perfusion 46,47,77,78,84) , restenosis 80) , the left ventricular (LV) function/remodeling 77,78) and long-term mortality 75) (Table 2).…”

“…Recently, Kramer et al showed that the presence of older thrombi is an independent predictor of longterm mortality in patients with STEMI treated with thrombus aspiration 75) . In that study, they classified the thrombi aspirated from 1,315 STEMI patients into fresh thrombi (＜1 day old) or older thrombi with lytic (1 to 5 days) or organized (＞5 days) changes immunohistochemically and showed that all-cause mortality was two-fold higher in the patients with older thrombi than in the patients with fresh thrombi at four years of follow-up (hazard ratio 1.82, 95% CI 1.17-2.85, p = 0.008).…”

The Emerging Role of Thrombus Aspiration in the Management of Acute Myocardial Infarction

“…14 Along with the clinical benefits of thrombus aspiration, retrieval of atherothrombotic material provides us with new possibilities to study the pathophysiology of thrombus formation, and thrombus characteristics may become of value in predicting outcome. In this issue of Circulation, Kramer et al 15 identify the age of aspirated thrombus as a predictor of long-term mortality in patients with STEMI treated with thrombus aspiration during primary PCI. Previously, these investigators have reported that in many STEMI patients who underwent thrombus aspiration during primary PCI within 6 hours of symptom onset, at least part of the thrombotic material was older than 1 day.…”

Microvascular Obstruction in Acute Myocardial Infarction

“…15 The platelet fresh component of the thrombus is unstable and prone to embolization into the distal microcirculation, causing MVO and interstitial inflammatory damage. 16 The embolism that occurs several days before the onset of symptoms was recently suggested by In the infarcted wall, MVO could impede coronary blood ejection into the venous circulation and could therefore cancel the benefit conferred in certain cases by coronary collateralization.…”