Adjunctive use of the Rinspiration system for fluidic thrombectomy during primary angioplasty: The Rinspiration international registry

A review of thrombectomy devices

Acute coronary syndrome is associated with a high incidence of thrombus. The presence of coronary thrombus is often not appreciated on coronary angiography; however, simultaneous use of angioscopy or intravascular ultrasound increases the detection of thrombus. Forceful coronary injection, passage of intracoronary devices, balloon angioplasty and stenting in the presence of thrombus contribute to distal embolization by disrupting the thrombus. Clinically, intracoronary thrombus is associated with higher rates of death, myocardial infarction and target vessel revascularization. Removal of thrombus results in the improvement of markers of perfusion, which includes resolution of ST segment elevation, higher myocardial blush grade, and an increase in final thrombolysis in myocardial infarction flow as well as lower mortality. In this article, the authors discuss different mechanical thrombectomy devices and the literature available for their use in acute coronary syndrome.

A prospective randomized trial of thrombectomy versus no thrombectomy in patients with ST-segment elevation myocardial infarction and thrombus-rich lesions: MUSTELA (MUltidevice Thrombectomy in Acute ST-Segment ELevation Acute Myocardial Infarction) trial

OBJECTIVES

The aim of this study was to evaluate whether thrombectomy during primary percutaneous coronary intervention (pPCI) in patients with high thrombus burden improves myocardial reperfusion and reduces infarct size.

BACKGROUND

Thrombectomy aims at reducing distal thrombotic embolization during pPCI, improving myocardial reperfusion and clinical outcome.

METHODS

We randomized 208 patients with high thrombus burden in a 1:1 ratio to either pPCI with thrombectomy (Group T) or standard pPCI (Group S). Thrombectomy was performed with either rheolytic or manual aspiration catheters. Three-month magnetic resonance imaging was performed to assess infarct size and transmurality and microvascular obstruction (MVO). The primary endpoints were ST-segment elevation resolution (STR) >70% at 60 min and 3-month infarct size.

RESULTS

The baseline profile was similar between groups, except for a higher rate of initial Thrombolysis In Myocardial Infarction flow grade 3 in Group S (p = 0.002). Group T showed a significantly higher rate of STR (57.4% vs. 37.3%; p = 0.004) and of final myocardial blush 3 (68.3% vs. 52.9%; p = 0.03). Group T and Group S did not differ with regard to infarct size (20.4 ± 10.5% vs. 19.3 ± 10.6%; p = 0.54) and transmurality (11.9 ± 12.0% vs. 11.6 ± 12.7%; p = 0.92), but Group T showed significantly less MVO (11.4% vs. 26.7%; p = 0.02) and a higher prevalence of inhomogeneous scar (p < 0.0001). One-year freedom from major adverse cardiac events was similar between groups.

CONCLUSIONS

Thrombectomy as an adjunct to pPCI in patients with high thrombus load yielded better post-procedural STR and reduced MVO at 3 months but was not associated with a reduction in infarct size and transmurality. Thromboaspiration in Patients With High Thrombotic Burden Undergoing Primary Percutaneous (Coronary Intervention; NCT01472718).

Early versus late ST-segment resolution and clinical outcomes after percutaneous coronary intervention for acute myocardial infarction

Background. Absence of complete ST-segment resolution (STR) after percutaneous coronary intervention (PCI) for ST-segment-elevation myocardial infarction (STEMI) is a determinant of mortality. Traditionally, STR is determined on the coronary care unit (CCU) 60 to 90 minutes after the initiation of reperfusion therapy. We studied the prognostic value of STR immediately after PCI. Methods. We analysed 223 consecutive patients with STEMI and successful PCI. Continuous ECG data were collected during PCI and at 30 minutes after arrival on the CCU (mean time 81±17 minutes after reflow of the culprit artery). Patients were divided into three groups: patients with complete STR immediately after PCI ('early'), patients with complete and persistent STR at 30 minutes on the CCU, but not immediately after PCI ('late') and patients without STR. One-year follow-up was obtained for death and rehospitalisation for major adverse cardiac events. Cox proportional hazards regression was used to evaluate the association between STR and outcome. Results. Early STR occurred in 115 (52%) and late STR in 43 (19%) patients. Patients with early or late STR had a lower incidence of one-year cardiac death than those without STR (1.9 vs. 9.2%; p=0.02). In contrast, rehospitalisation occurred more frequently in patients with early or late STR (20.3 vs. 6.2%; p=0.009). As compared with patients without STR, early and late STR had a similar prognostic value (hazard ratios [95% confidence interval] for cardiac death 0.40 [0.08-2.03] and 0.25 [0.03-2.08]).Conclusions. We found no (major) change in prognostic value of STR during the 0 to 90 minutes time window after PCI. (Neth Heart J 2010;18:416-22.).

Current status of distal embolization in percutaneous coronary intervention: mechanical and pharmacological strategies

Distal embolization during percutaneous coronary intervention for acute myocardial infarction or saphenous vein graft disease may result in microvascular obstruction and the 'no-reflow' phenomenon. The incidence of distal embolization ranges from 2 to 42% in saphenous vein graft intervention and from 6 to 15% in primary percutaneous coronary intervention and is associated with impaired myocardial perfusion and poor outcome. Several mechanical and pharmacological strategies have been proposed to prevent or to treat embolization in percutaneous coronary intervention and have been tested in clinical trials. The pivotal role of distal embolization in the pathophysiology of microvascular obstruction will lead to the further development of preventive and therapeutic strategies. Strategies to counteract distal embolization and future directions are discussed in this review.

Role of thrombectomy in acute myocardial infarction

Acute ST elevation myocardial infarction results from atherosclerotic plaque rupture with subsequent thrombus formation, leading to complete or near complete occlusion of an epicardial coronary artery. Minimization of the mechanical obstruction from this thrombus remains the main goal of therapy in ST elevation myocardial infarction. Primary percutaneous coronary intervention for an ST elevation myocardial infarction appears to be the preferred mode of revascularization over thrombolytic therapy if the door-to-balloon time target of 90 min is achievable. The idea of reducing the thrombus burden with the use of devices as an adjunct to percutaneous coronary intervention is an attractive one. Several thrombectomy devices have been studied in randomized clinical trials, but no definitive conclusions have emerged, owing to conflicting results and variable clinical end points. This article intends to shed further light on the potential role of thrombectomy in the treatment of acute myocardial infarction.