Effects of percutaneous coronary arterial thrombectomy during acute myocardial infarction on left ventricular remodeling

Reducing Cardiac Injury during ST-Elevation Myocardial Infarction: A Reasoned Approach to a Multitarget Therapeutic Strategy

The significant reduction in ‘ischemic time’ through capillary diffusion of primary percutaneous intervention (pPCI) has rendered myocardial-ischemia reperfusion injury (MIRI) prevention a major issue in order to improve the prognosis of ST elevation myocardial infarction (STEMI) patients. In fact, while the ischemic damage increases with the severity and the duration of blood flow reduction, reperfusion injury reaches its maximum with a moderate amount of ischemic injury. MIRI leads to the development of post-STEMI left ventricular remodeling (post-STEMI LVR), thereby increasing the risk of arrhythmias and heart failure. Single pharmacological and mechanical interventions have shown some benefits, but have not satisfactorily reduced mortality. Therefore, a multitarget therapeutic strategy is needed, but no univocal indications have come from the clinical trials performed so far. On the basis of the results of the consistent clinical studies analyzed in this review, we try to design a randomized clinical trial aimed at evaluating the effects of a reasoned multitarget therapeutic strategy on the prevention of post-STEMI LVR. In fact, we believe that the correct timing of pharmacological and mechanical intervention application, according to their specific ability to interfere with survival pathways, may significantly reduce the incidence of post-STEMI LVR and thus improve patient prognosis.

Manual aspiration thrombectomy in acute ST elevation myocardial infarction: New gold standard

Percutaneous coronary intervention (PCI) is the preferred method to treat ST segment myocardial infarction (STEMI). The use of thrombus aspiration (TA) may be particularly helpful as part of the PCI process, insofar as the presence of thrombus is essentially a universal component of the STEMI process. This article reviews evidence favoring the routine use of TA, and the limitations of these data. Based on current evidence, we consider TA to be an important maneuver during STEMI PCI, even in the absence of visible angiographic thrombus, and recommend it whenever the presence of thrombus is likely.

Impact of thrombectomy with EXPort Catheter in Infarct-Related Artery during Primary Percutaneous Coronary Intervention (EXPIRA Trial) on cardiac death

In ST-segment elevation myocardial infarction (STEMI) impairment of microcirculatory function is a negative independent predictor of myocardial function recovery. In the Impact of Thrombectomy with EXPort Catheter in Infarct-Related Artery during Primary Percutaneous Coronary Intervention (PCI; EXPIRA) trial we found that manual thrombectomy resulted in a better myocardial reperfusion expressed by an improved procedural outcome and a decrease of infarct size compared to conventional PCI. The aim of the present study was to investigate whether the early efficacy of thrombus aspiration translates into very long-term clinical benefit. We randomized 175 patients with STEMI with occlusive thrombus at baseline undergoing primary PCI to thromboaspiration with a manual device (Export Medtronic, n = 88) or standard PCI (n = 87). No differences in baseline, clinical, and angiographic preprocedural findings were observed between the 2 groups except for incidence of hypertension and cholesterol levels. After 24 months major adverse cardiac events were 13.7% versus 4.5% (p = 0.038, log-rank test) and cardiac death was 6.8% versus 0% (p = 0.012, log-rank test). A strict correlation was observed between cardiac death incidence and tissue reperfusion parameters (postprocedural myocardial blush grade and ST-segment resolution). In conclusion, manual thrombus aspiration before stenting of the infarct-related artery in selected patients with STEMI improving myocardial reperfusion significantly decrease cardiac death and major adverse cardiac events at 2 years.

Long-term outcome after thrombectomy in acute myocardial infarction

BACKGROUND

Current data appear in favour of thrombectomy for ST-elevation myocardial infarction (STEMI). However, information on long-term outcome after thrombectomy is limited. We performed a retrospective long-term study to assess the risk of cardiac re-hospitalizations and survival after discharge from the index hospitalization for STEMI.

METHODS

Patients originally randomized to percutaneous coronary intervention (PCI) with thrombectomy vs. standard PCI were included in a retrospective long-term observational study. The primary study endpoint was the combined risk for all-cause death or cardiac re-hospitalization after index discharge under optimal medical therapy. The cumulative number of cardiac hospitalization days and ventricular remodelling assessed by echocardiography and plasma biomarkers were secondary endpoints.

RESULTS

Of 94 STEMI patients who had been randomized between 11/2000 and 03/2003, 89 patients consented to long-term follow-up. A total of 43 patients had been allocated to thrombectomy and 46 to standard primary PCI. The minimum follow-up time was 1115 days. There was a significantly lower risk for death or cardiac re-hospitalization for patients of the thrombectomy group (hazard ratio = 0.69, 95% CI: 0.49-0.98, P = 0.036). The incidence of recurrent myocardial infarction was not different (P = 0.343). No differences in cardiac remodelling were detected by echocardiography, with the exception that heart-type fatty acid binding protein at 53.2 +/- 17 months was lower in the thrombectomy group (P = 0.045).

CONCLUSION

Thrombectomy in STEMI may decrease the long-term risk for death or cardiac re-hospitalization.

Effect of thrombus aspiration on infarct size and left ventricular function in high-risk patients with acute myocardial infarction treated by percutaneous coronary intervention. Results of a prospective controlled pilot study

BACKGROUND

Thrombus aspiration devices have been shown to improve reperfusion criteria and to reduce distal embolization in patients treated by percutaneous coronary interventions (PCI) in the acute phase of ST-elevation myocardial infarction (STEMI). There are, however, little data about their efficacy in the reduction of infarct size.

METHODS

We sought to assess in a prospective randomized trial the impact of thrombus aspiration on infarct size and severity and on left ventricular function in high-risk patients with a first STEMI. The primary end point was scintigraphic infarct size, and secondary end points were infarct severity and regional and global left ventricular function. Forty-four patients with completely occluded (Thrombolysis in Myocardial Infarction flow 0-1) proximal segments of infarct-related artery were randomly assigned to thrombus aspiration group with the Export catheter (n = 20) (Medtronic, Inc, Minneapolis, MN) or PCI-only group. A rest Tc-99-mibi gated single-photon emission computed tomographic and contrast-enhanced magnetic resonance imaging were performed 6 +/- 2 days later.

RESULTS

Infarct size was comparable in patients in the thrombus aspiration group and PCI-only group (30.6% +/- 15.8% vs 28.5% +/- 17.9% of the left ventricle, P = .7) as was infarct severity in infarct-related artery territory (55% +/- 12% vs 55% +/- 14%, P = .9). Transmurality score as assessed by magnetic resonance imaging was similar in both groups (2.03 +/- 1.05 vs 2.16 +/- 1.21, P = .7). There was no impact of thrombus aspiration on other secondary end points.

CONCLUSION

In our study, thrombus aspiration with the Export catheter performed as adjunctive therapy in high-risk patients with total occlusion of the proximal part of major coronary arteries does not decrease infarct size or severity and has no effect on left ventricular regional and global function.

Primary angioplasty and routine utilization of thrombus aspiration devices: feasibility and results in a consecutive series of 486 patients

BACKGROUND

Primary percutaneous transluminal coronary angioplasty (PTCA) is the treatment of choice for acute ST-segment elevation myocardial infarction (STEMI) in high-volume centres with experienced operators, but is often limited by a suboptimal microvascular perfusion due to distal embolization and impaired myocardial perfusion. The present study investigates whether routine use of thrombus aspiration (TA) devices is feasible in daily practice, along with its safety and effectiveness.

METHODS

This study is based on a series of 486 consecutive STEMI patients treated at our single institution by the same three operators (from 2001 to 2005). They underwent primary PTCA with or without TA according to these angiographic features: infarct related artery (IRA) diameter>or=3 mm; thrombotic occlusion or angiographic evidence of thrombus; absence of severe proximal tortuosity or calcification. We evaluate the efficacy of TA in terms of procedural success, coronary thrombolysis in myocardial infarction (TIMI) flow, myocardial blush grade (MBG), resolution>or=50% of ST segment elevation, and clinical events during hospital stay and at 6-month follow-up.

RESULTS

A total of 486 primary PTCAs were performed, 217 (44.6%) with TA as a first device using RESCUE (n=65), EXPORT (n=140) and DIVER-CE (n=12) catheters. In 141 (65%) cases, macroscopic material was aspirated. The patients submitted to TA were more often males (84.7% versus 71.7%, P<0.05) and younger (age: 61.02+/-11.91 versus 64.47+/-10.59 years, P<0.01) than patients treated with traditional PTCA and the IRA was more frequently occluded at angiography (basal TIMI 0: 70.5% versus 47.9%). Application of the TA did not increase the complexity of the procedure (door-to-balloon times, minutes of fluoroscopy and amount of dye). TA alone was effective to restore TIMI 3 flow in 187 cases (86.2%) as a first device and in three other cases (1.4%) after predilatation with balloon. Direct stenting without predilatation was possible in 144 cases (66.4%) after TA. TA was not effective in 27 cases (12.4%) and this subgroup had both angiographic and clinical unfavourable results in comparison with the effective TA group (final TIMI 1 in 11.1% versus 0.5%, P<0.015; final MBG 1 in 55.5% versus 9.5%, P<0.001; lack of ST segment resolution>or=50% in 44.4% versus 7.9%, P<0.001; in-hospital mortality 14.8% versus 2.6%, P<0.05 and mortality at 6 months 18.5% versus 3.1%, P<0.05). In the whole TA population, final TIMI 3 flow was achieved in 203 cases (93.5%), final MBG 3 in 145 cases (66.8%) and ST segment resolution>or=50% in 185 cases (85.2%), in-hospital mortality was 4.1% and cumulative mortality at 6-month follow-up was 5.5%.

CONCLUSIONS

In our case series, 486 consecutive unselected patients with STEMI were treated in a primary PTCA high-volume centre using TA devices. Our study demonstrates that, in STEMI patients treated with primary PTCA, a routine strategy with TA before angioplasty guided by angiographic selection criteria is feasible in almost 50% of cases, is safe and effective, does not increase procedural time and offers good results in terms of tissue perfusion, both epicardial (TIMI flow) and myocardial (MBG, ST regression). When successfully performed, TA identifies a population with favourable in-hospital and 6-month outcome.

Intracoronary Thrombectomy with the Export Aspiration Catheter Before Angioplasty in Patients with ST-Segment Elevation Myocardial Infarction

OBJECTIVE

We aimed to assess the safety and feasibility of thrombectomy with the Export Aspiration Catheter (EAC) before angioplasty, and its ability to improve angiographic results in patients with ST-segment elevation myocardial infarction (STEMI).

BACKGROUND

Distal embolization of atherothrombotic material often occurs during angioplasty in STEMI, compromising optimal myocardial reperfusion.

METHODS

We performed a thrombus-aspiration with EAC prior to angioplasty in 64 consecutive patients with STEMI. Successful thrombectomy was defined as an improvement of TIMI flow grade >or=1.

RESULTS

Successful thrombectomy (increase of TIMI flow >or=1) was achieved in 40 patients (62.5%). Mean TIMI flow grade increased from 0.7 +/- 1 to 1.9 +/- 1.2 (p < 0.0001) after thrombectomy. TIMI flow grade 3 was observed more frequently after EAC compared with guidewire alone (51.5% vs. 9%, p = 0.0062). Direct stenting was performed in most of the patients (n = 41, 64%). Distal embolization and no reflow/slow flow phenomenon occurred in 8 patients (12.5%). No vessel injury after EAC thrombectomy was reported. After treatment with balloon angioplasty and/or stenting, final TIMI flow grade 3 was achieved in 54 patients (84.5%). By multivariate analysis, ischemic time < 6 hours was a significant independent predictor of successful thrombectomy (p = 0.0437).

CONCLUSIONS

Our series suggests that EAC thrombectomy prior to angioplasty in the setting of STEMI is safe and feasible. It might reduce the culprit coronary lesion's thrombus burden, leading to improved flow restoration and myocardial reperfusion. Further large randomized studies are warranted to confirm these preliminary results and to assess the impact of thrombus-aspiration on infarct size as well as on clinical outcomes.

Prospective, Multicenter Study of Thrombectomy in Patients with Acute Myocardial Infarction: The X-Tract AMI Registry

BACKGROUND

Thrombus and soft, friable atheromatous plaque are present in the majority of patients with acute myocardial infarction (AMI), and may result in distal embolization and no reflow during primary angioplasty. Thrombectomy prior to intervention may decrease thromboembolic complications and improve outcomes.

METHODS

The X-TRACT AMI registry was a prospective, multicenter study evaluating the safety and feasibility of the X-Sizer thrombectomy system prior to primary angioplasty in native coronary arteries and saphenous vein grafts (SVGs) in patients presenting within 24 hours AMI onset.

RESULTS

A total of 216 patients (220 target lesions) with AMI were enrolled at 28 U.S. sites, with approximately 90% of lesions in native coronary arteries and 10% in SVGs. Preprocedural TIMI 0/1 flow was present in 56% of patients, with thrombus in 76%. Glycoprotein IIb/IIIa inhibitors were used in 86% of patients, and bare metal stents were implanted in 94% (mean stent length 26 mm). TIMI-3 flow was present in 27% of patients at baseline, in 81% after thrombectomy, and in 92% following PCI. Normal myocardial blush grade 3 was present in 6% of patients at baseline, and in 52% postprocedure. At 30 and 360 days, 93.1% and 80.8% of patients were free from major cardiovascular events.

CONCLUSION

In this broad multicenter experience, use of the X-Sizer device prior to stent implantation in thrombus containing native coronary arteries and diseased SVGs was feasible and associated with high rates of normalized postprocedural epicardial blood flow and myocardial blush, warranting further study as an adjunct during primary angioplasty.

[Intracoronary thrombectomy with the Export Aspiration Catheter before angioplasty in patients with ST-segment elevation myocardial infarction]

OBJECTIVES

We aimed to assess the safety and feasibility of thrombectomy with the Export Aspiration Catheter (EAC) before angioplasty, and its ability to improve angiographic results in patients with ST-segment elevation myocardial infarction (STEMI).

BACKGROUND

Distal embolization of atherothrombotic material often occurs during angioplasty in STEMI, compromising optimal myocardial reperfusion.

METHODS

We performed a thrombus-aspiration with EAC prior to angioplasty in 64 consecutive patients with STEMI. Successful thrombectomy was defined as an improvement of TIMI flow grade > or =1.

RESULTS

Successful thrombectomy (increase of TIMI flow > or =1) was achieved in 40 patients (62.5%). Mean TIMI flow grade increased from 0.7 +/- 1 to 1.9 +/- 1.2 (P < 0.0001) after thrombectomy. TIMI flow grade 3 was observed more frequently after EAC compared with guidewire alone (51.5 vs. 9%, P = 0.0062). Direct stenting was performed in most of patients (N=41, 64%). Distal embolization and noreflow/slowflow phenomenon occurred in 8 patients (12.5%). No vessel injury after EAC thrombectomy was reported. After treatment with balloon angioplasty and/or stenting, final TIMI flow grade 3 was achieved in 54 patients (84.5%). By multivariate analysis, ischemic time <6 h was a significant independent predictor of successful thrombectomy (P = 0.0437).

CONCLUSIONS

Our series suggests that EAC thrombectomy prior to angioplasty in the setting of STEMI is safe and feasible. It might reduce the culprit coronary lesion's thrombus burden, leading to improved flow restoration and myocardial reperfusion. Further large randomized studies are warranted to confirm these preliminary results and to assess the impact of thrombus-aspiration on infarct size as well as on clinical outcomes.

Effects of intravenous administration of tissue plasminogen activator before thrombectomy in patients with acute myocardial infarction

BACKGROUND

Myocardial salvage after acute myocardial infarction (AMI) largely depends on the removal of infarct-related thrombus. Although both thrombolysis and thrombectomy are effective strategies to remove thrombus, there is a paucity of reports regarding the benefit of the combination therapy. Therefore, the efficacy of intravenous administration with mutant tissue plasminogen activator (Mt-PA) before thrombectomy and ordinary percutaneous coronary intervention (PCI) was evaluated.

METHODS AND RESULTS

Consecutive 44 AMI patients without contraindication of Mt-PA were enrolled in the study and randomly assigned to thrombectomy with Mt-PA pre-administration (group T) or thrombectomy alone (group N). Although Thrombolysis in Myocardial Infarction (TIMI) grade before PCI and TIMI myocardial perfusion grade immediately after PCI were significantly greater in group T (p<0.05), there was no improvement of left ventricular ejection fraction immediately and 6 months after PCI.

CONCLUSIONS

These results suggest that intravenous administration with Mt-PA before thrombectomy had no significant benefit in the salvage of infracted myocardium over thrombectomy alone, despite improvement of coronary microcirculation immediately after PCI.

Relation of atherothrombosis burden and volume detected by intravascular ultrasound to angiographic no-reflow phenomenon during stent implantation in patients with acute myocardial infarction

This study investigated the mechanism of occurrence of the no-reflow phenomenon during stent implantation in patients with acute myocardial infarction (AMI) using intravascular ultrasound (IVUS) with volumetric analysis. Of 70 patients with AMI who underwent IVUS-guided stent implantation within 24 hours of symptom onset, 12 developed decreased Thrombolysis In Myocardial Infarction flow grade during stent implantation and without subsequent restoration to Thrombolysis In Myocardial Infarction flow grade before stenting. External elastic membrane cross-sectional area and maximum diameter at the culprit lesion as measured by IVUS before stent implantation were significantly larger in the no-reflow group (n = 12) than in the normal reflow group (n = 58; 20.1 +/- 6.5 vs 16.4 +/- 4.3 mm2, p = 0.015 for cross-sectional area and 5.2 +/- 0.9 vs 4.8 +/- 0.6 mm, p = 0.049 for maximum diameter). Plaque volume, volumetric plaque burden (plaque volume/external elastic membrane volume), and change in plaque volume during stent implantation (plaque volume after vs before) were significantly greater in the no-reflow group than in the normal reflow group (239 +/- 142 vs 178 +/- 72 mm3, p = 0.030; 0.76 +/- 0.07 vs 0.71 +/- 0.06, p = 0.010; and -46 +/- 63 vs -11 +/- 37 mm3, p = 0.013, respectively). In conclusion, high atherothrombotic burden and decreased plaque volume as detected by IVUS may be risk factors for development of the no-reflow phenomenon during stent implantation in patients with AMI.

Mechanical thrombectomy options in complex percutaneous coronary interventions

Percutaneous coronary interventions (PCI) of thrombus-containing lesions are associated with an increased risk of acute complications and poorer long term vessel patency. Dealing with these vessels provides many technical challenges, especially with the significant risk of coronary no reflow and distal embolization. Pharmacological strategies, including intravenous and intracoronary glycoprotein IIbIIIa inhibitors reduce intracoronary thrombus propagation, improve TIMI flow and are associated with a reduction in adverse event rates. Mechanical strategies (particularly embolic protection and thrombectomy catheters) help to improve coronary blood flow and myocardial perfusion. However, their impact on clinical outcomes is less clear. The use of embolic protection devices is associated with better perfusion, blood flow, and clinical outcomes among patients undergoing saphenous vein graft (SVG) PCI. However, the role for these devices in primary PCI and native coronary artery interventions is uncertain. This study examines the current approaches to manage thrombotic lesions during PCI and reviews the evidence in support of the different mechanical thrombectomy options that are available to the interventional cardiologist.

Impact of intracoronary aspiration thrombectomy during primary angioplasty on left ventricular remodelling in patients with anterior ST elevation myocardial infarction

OBJECTIVE

To evaluate prospectively the impact on left ventricular (LV) remodelling of an intracoronary aspiration thrombectomy device as adjunctive therapy in primary percutaneous coronary intervention (PCI) in patients with anterior ST elevation myocardial infarction (STEMI).

METHODS

76 consecutive patients with anterior STEMI (65.3 (11.2) years, 48 men) were randomly assigned to intracoronary thrombectomy and stent placement (n = 38) or to conventional stenting (n = 38) of the infarct related artery. Each patient underwent transthoracic echocardiography immediately after PCI and at six months. At the time of echocardiographic control, major adverse cardiovascular events (MACE) in terms of death, new onset of myocardial infarction, and hospitalisation for heart failure were also evaluated.

RESULTS

After a successful primary PCI, patients in the thrombectomy group achieved a higher rate of post-procedure myocardial blush grade 3 (36.8% v 13.1%, p = 0.03) and effective ST segment resolution at 90 minutes (81.6% v 55.3%, p = 0.02). Six months after the index intervention, 19 patients (26.8%) developed LV dilatation, defined as an increase in end diastolic volume (EDV) >or= 20%: 15 in the conventional group and four in the thrombectomy group (p = 0.006). Accordingly, at six months patients treated conventionally had significantly higher end systolic volumes (82 (7.7) ml v 75.3 (4.9) ml, p < 0.0001) and EDV (152.5 (18.1) ml v 138.1 (10.7) ml, p < 0.0001) than patients treated with thrombectomy. No differences in cumulative MACE were observed (10.5% in the conventional group v 8.6% in the thrombectomy group, not significant).

CONCLUSION

Compared with conventional stenting, adjunctive aspiration thrombectomy in successful primary PCI seems to be associated with a significantly lower incidence of LV remodelling at six months in patients with anterior STEMI.

Effects of Percutaneous Coronary Thrombectomywith the X-Sizer Catheter on Epicardial Flow and Microvascular Function in Acute Coronary Syndromes

During percutaneous coronary intervention, slow coronary flow and distal embolization are still important problems, especially in cases with intracoronary thrombus. The aim of this study was to learn the effectiveness and early term results of thrombectomy with the X-SIZER catheter system in acute coronary syndrome. Twenty-nine patients (22 [76%] men; 55.9 ± 11.1 years) with acute coronary syndrome and intracoronary thrombus detected in coronary angiography were included into the study. X-sizer thrombectomy was applied to 14 of the patients, and conventional percutaneous transluminal coronary angioplasty (PTCA) was applied to the others. Baseline characteristics were similar in both groups. Mean thrombolysis in myocardial infarction (TIMI) flow increased from 0.8 ± 0.9 to 2.4 ± 0.6 in X-sizer-treated patients (p<0.001) and TIMI 3 flow was maintained in 71.4% of the patients. Similary, mean TIMI flow increased from 0.36 ± 0.81 to 2.73 ± 0.47 in conventional PTCA-treated patients (p<0.001) and TIMI 3 flow was maintained in 73% of the patients (NS). Mean myocardial blush grade (MBG) increased from 0.7 ± 0.7 to 2.6 ± 0.6 in X-sizer-treated patients (p<0.001) and from 0.27 ± 0.65 to 2.36 ± 0.67 in the conventional PTCA-treated patients (p<0.001). Postprocedural MBG 3 was obtained in 64.3% of X-Sizer-treated patients and in 45% of controls. Although microvascular function in the thrombectomy-applied patients was found better, there was no significant difference between the two groups. Furthermore it was detected that the use of tirofiban yielded no additional improvement in epicardial and microvascular flow. In acute coronary syndromes, use of X-sizer in addition to primary percutaneous coronary interventions is a safe and relatively effective method in the prevention of distal embolization.