Thrombus aspiration before primary angioplasty improves myocardial reperfusion in acute myocardial infarction: the DEAR-MI (Dethrombosis to Enhance Acute Reperfusion in Myocardial Infarction) study

Management of 'no-reflow' complicating reperfusion therapy

No-reflow phenomenon, defined as inadequate myocardial perfusion of the adequately dilated target vessel without evidence of angiographic mechanical obstruction. It is a multifactorial, well-recognised, secondary phenomenon following reperfusion therapy such as thrombolysis or percutaneous coronary interventions (PCI). The pathophysiological mechanisms leading to the no-reflow state are incompletely understood. Embolization of the atheromatous material to the distal vasculature and intense arteriole vasospasm caused by microembolization of platelet-rich thrombi that release vasoactive agents resulting in microvascular obstructions are likely mechanisms. Current prophylaxis and management strategies are derived from limited clinical data. Intracoronary verapamil, adenosine and nitroprusside have been most frequently studied and administered for angiographic no-reflow during PCI for acute myocardial infarction or saphenous vein graft (SVG) lesions and have been shown to improve epicardial flow and microvascular perfusion. The use of distal embolic protection devices in SVG interventions also provide microvascular protection and improve clinical outcomes. However, by far the most important measures are prevention and anticipation during PCI as once no-reflow established, complete reversal of the situation may not be possible.

Adjunctive manual thrombectomy improves myocardial perfusion and mortality in patients undergoing primary percutaneous coronary intervention for ST-elevation myocardial infarction: a meta-analysis of randomized trials

AIMS

The benefits of adjunctive mechanical devices to prevent distal embolization in patients with acute myocardial infarction (AMI) are still a matter of debate. Growing interests are on manual thrombectomy devices as compared with other mechanical devices. In fact, they are inexpensive and user-friendly devices, and thus represent an attractive strategy. The aim of the current study was to perform an updated meta-analysis of randomized trials conducted with adjunctive manual thrombectomy devices to prevent distal embolization in AMI.

METHODS AND RESULTS

The literature was scanned by formal searches of electronic databases [MEDLINE, CENTRAL, EMBASE, and The Cochrane Central Register of Controlled trials (http://www.mrw.interscience.wiley.com/cochrane/Cochrane_clcentral_articles_fs.html)] from January 1990 to May 2008, the scientific session abstracts (from January 1990 to May 2008) and oral presentation and/or expert slide presentations (from January 2002 to May 2008) [on transcatheter coronary therapeutics (TCT), AHA (American Heart Association), ESC (European Society of Cardiology), ACC (American College of Cardiology) and EuroPCR websites]. We examined all randomized trials on adjunctive mechanical devices to prevent distal embolization in AMI. The following keywords were used: randomized trial, myocardial infarction, reperfusion, primary angioplasty, rescue angioplasty, thrombectomy, thrombus aspiration, manual thrombectomy, Diver catheter, Pronto catheter, Export catheter, thrombus vacuum aspiration catheter. Information on study design, type of device, inclusion and exclusion criteria, number of patients, and clinical outcome was extracted by two investigators. Disagreements were resolved by consensus. A total of nine trials with 2417 patients were included [1209 patients (50.0%) in the manual thrombectomy device group and 1208 (50%) in the control group]. Adjunctive manual thrombectomy was associated with significantly improved postprocedural TIMI (thrombolysis in myocardial infarction) 3 flow (87.1 vs. 81.2%, P < 0.0001), and postprocedural MBG 3 (myocardial blush grade 3) (52.1 vs. 31.7%, P < 0.0001), less distal embolization (7.9 vs. 19.5%, P < 0.0001), and significant benefits in terms of 30-day mortality (1.7 vs. 3.1%, P = 0.04).

CONCLUSION

This meta-analysis demonstrates that, among patients with AMI treated with percutaneous coronary intervention, the use of adjunctive manual thrombectomy devices is associated with better epicardial and myocardial perfusion, less distal embolization and significant reduction in 30-day mortality. Thus, adjunctive manual thrombectomy devices, if not anatomically contraindicated, should be routinely used among STEMI (ST-segment elevation myocardial infarction) patients undergoing primary angioplasty.

Functional recovery after acute myocardial infarction: comparison between angiography, electrocardiography, and cardiovascular magnetic resonance measures of microvascular injury

OBJECTIVES

We examined the relation between angiographic, electrocardiographic, and gadolinium-enhanced cardiovascular magnetic resonance (CMR) characteristics of microvascular obstruction (MVO), and their predictive value on functional recovery after acute myocardial infarction (AMI).

BACKGROUND

Microvascular obstruction on CMR has been shown to predict left ventricular (LV) remodeling, but it is not well known how it compares with commonly used criteria of microvascular injury, and earlier reports have produced conflicting results on the significance and extent of MVO.

METHODS

Thrombolysis In Myocardial Infarction (TIMI) flow grade, myocardial blush grade (MBG), and ST-segment resolution were assessed in 60 patients with AMI treated with primary stenting. Cardiovascular magnetic resonance was performed between 2 and 9 days after revascularization to determine early MVO on first-pass perfusion imaging, late MVO on late gadolinium-enhanced imaging, and infarct size and transmural extent. Cine imaging was used to determine LV volumes and global and regional function at baseline and 4-month follow-up.

RESULTS

Early and late MVO were both related to incomplete ST-segment resolution (p = 0.002 and p = 0.01, respectively), but not to TIMI flow grade and MBG. Of all angiographic, electrocardiographic, and CMR variables, late MVO was the strongest parameter to predict changes in end-diastolic volume (beta = 0.53; p = 0.001), end-systolic volume (beta = 8.67; p = 0.001), and ejection fraction (beta = 3.94; p = 0.006) at follow-up. Regional analysis showed that late MVO had incremental diagnostic value to transmural extent of infarction (odds ratio: 0.18; p < 0.0001).

CONCLUSIONS

In patients after revascularized AMI, late MVO proved a more powerful predictor of global and regional functional recovery than all of the other characteristics, including transmural extent of infarction.

Cardiac death and reinfarction after 1 year in the Thrombus Aspiration during Percutaneous coronary intervention in Acute myocardial infarction Study (TAPAS): a 1-year follow-up study

BACKGROUND

Percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction can be complicated by spontaneous or angioplasty-induced embolisation of atherothrombotic material. Distal blockage induces microvascular obstruction and can result in less than optimum reperfusion of viable myocardium. The Thrombus Aspiration during Percutaneous coronary intervention in Acute myocardial infarction Study (TAPAS) found that thrombus aspiration resulted in improved myocardial reperfusion compared with conventional PCI, but whether this benefit improves clinical outcome is unknown. We aimed to investigate whether the early efficacy of thrombus aspiration seen in TAPAS translated into clinical benefit after 1 year.

METHODS

Patients with ST-elevation myocardial infarction enrolled at the University Medical Centre Groningen were randomly assigned in a 1:1 ratio to either thrombus aspiration or conventional treatment, before undergoing initial coronary angiography. Exclusion criteria were rescue PCI after thrombolysis and known existence of a concomitant disease with life expectancy less than 6 months. Of the 1071 patients enrolled between January, 2005, and December, 2006, vital status at or beyond 1 year after randomisation was available for 1060 (99%). The primary endpoint was cardiac death or non-fatal reinfarction after 1 year, and analysis was by intention to treat. The TAPAS trial is registered with Current Controlled Trials number ISRCTN16716833.

FINDINGS

Cardiac death at 1 year was 3.6% (19 of 535 patients) in the thrombus aspiration group and 6.7% (36 of 536) in the conventional PCI group (hazard ratio [HR] 1.93; 95% CI 1.11-3.37; p=0.020). 1-year cardiac death or non-fatal reinfarction occurred in 5.6% (30 of 535) of patients in the thrombus aspiration group and 9.9% (53 of 536) of patients in the conventional PCI group (HR 1.81; 95% CI 1.16-2.84; p=0.009).

INTERPRETATION

Compared with conventional PCI, thrombus aspiration before stenting of the infarcted artery seems to improve the 1-year clinical outcome after PCI for ST-elevation myocardial infarction.

Use of the TIMI frame count in the assessment of coronary artery blood flow and microvascular function over the past 15 years

Since its introduction, the TIMI frame count method has contributed to the understanding of the pathophysiology of coronary artery disease. In this article, the evolution of the TFC method and its applicability in the assessment of various therapeutic modalities are described.

Time-dependent benefit of initial thrombosuction on myocardial reperfusion in primary percutaneous coronary intervention

BACKGROUND

In ST-segment elevation acute myocardial infarction (STEMI), dislodgement of thrombus within the culprit artery during primary percutaneous coronary intervention (PCI) may cause distal embolisation and impaired myocardial reperfusion. Clinical results of thromboembolic protection strategies have been controversial. We conducted this study to investigate whether the benefit of thrombus removal is time dependent.

METHODS

Seventy-four STEMI patients within 12 h from onset were randomised to receive either primary PCI with initial thrombosuction (IT) or standard strategy. Results were analysed in subgroups according to the onset-to-lab time intervals (subgroup 1: 0-240 min, subgroup 2: 241-480 min and subgroup 3: 481-720 min).

RESULTS

The primary end-points were improvements in thrombolysis in myocardial infarction flow (DeltaTIMI) and myocardial blush grade (DeltaMBG) postprocedure. Better DeltaTIMI (2.2 +/- 1.1 vs. 1.5 +/- 1.3, p = 0.014) and DeltaMBG (2.3 +/- 1.1 vs. 1.0 +/- 1.5, p < 0.001) were observed in IT patients, compared with standard PCI patients. In onset-to-lab time subgroup analysis, the difference between IT and standard PCI is significant only in subgroup 2 (DeltaTIMI 2.6 +/- 1.0 vs. 1.3 +/- 1.2, p = 0.007; DeltaMBG 2.6 +/- 0.9 vs. 1.0 +/- 1.1, p = 0.010), but not in the other two subgroups.

CONCLUSIONS

This prospective randomised study shows that primary PCI with IT may improve epicardial flow and myocardial reperfusion in patients with STEMI, and this benefit is the most significant in patients treated within 4-8 h after symptom onset.

Randomized comparison of distal protection versus conventional treatment in primary percutaneous coronary intervention: the drug elution and distal protection in ST-elevation myocardial infarction (DEDICATION) trial

OBJECTIVES

The purpose of this study was to evaluate the use of distal protection during percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) in native coronary vessels.

BACKGROUND

Embolization of material from the infarct-related lesion during PCI may result in impaired myocardial perfusion and worsen the prognosis. Previous attempts to protect the microcirculation during primary PCI have had conflicting results.

METHODS

We randomly assigned 626 patients with STEMI referred within 12 h to have PCI performed with (n = 312) or without (n = 314) distal protection. The primary end point was complete (>or=70%) ST-segment resolution detected by continuous ST-segment monitoring. Blood levels of troponin-T and creatine kinase-MB were monitored before and after the procedure, and echocardiographic determination of the left ventricular wall motion index (WMI) was performed before discharge.

RESULTS

Patients were well matched in terms of demographic and angiographic baseline characteristics. There was no significant difference in the occurrence of the primary end point (76% vs. 72%, p = 0.29), no difference in maximum troponin-T (4.8 microg/l and 5.0 microg/l, p = 0.87) or maximum creatine kinase-MB (185 microg/l and 184 microg/l, p = 0.99), and no difference in median WMI (1.70 vs. 1.70, p = 0.35). The rate of major adverse cardiac and cerebral events (MACCE) 1 month after PCI was 5.4% with distal protection and 3.2% with conventional treatment (p = 0.17).

CONCLUSIONS

The routine use of distal protection by a filterwire system during primary PCI does not seem to improve microvascular perfusion, limit infarct size, or reduce the occurrence of MACCE.

Treatment of a large left main coronary artery thrombus by aspiration thrombectomy

A left main coronary artery thrombosis is a life-threatening condition demanding immediate therapeutic management. Traditional treatment options include thrombolysis, percutaneous coronary intervention (PCI) with stenting or cardiac bypass surgery. The number of reported cases in which aspiration thrombectomy has been used is limited. Indications for this therapeutic approach are determined by coronary anatomy, clinical stability, and hemodynamic condition of the patient. We present the case of an acute left main coronary artery thrombosis leading to progressive deterioration of left ventricle function that was successfully treated with aspiration thrombectomy.

Elevation of matrix metalloproteinases and interleukin-6 in the culprit coronary artery of myocardial infarction

BACKGROUND

Interleukin-6 (IL-6) and metalloproteinases (MMPs) are involved in the instability of vulnerable plaque associated with the induction of acute myocardial infarction (AMI). We examined the regional changes of cytokines, MMPs and adhesion molecules in patients with AMI to elucidate how these factors are involved in the onset of AMI.

MATERIALS AND METHODS

One hundred and twenty-two patients with AMI were included. Blood was aspirated from the culprit coronary artery with a thrombectomy catheter, and was also sampled from peripheral veins during the coronary intervention. Control samples were obtained from the peripheral blood of age-matched patients.

RESULTS

The serum levels of IL-6 (P < 0.05), tumour necrosis factor-alpha (P < 0.005), MMP-1 (P < 0.001), MMP-13 (P < 0.001), soluble intercellular adhesion molecule-1 (P < 0.005), and soluble vascular cellular adhesion molecule-1 (P < 0.05) in peripheral blood were significantly higher in the AMI group than in the controls. Aspirated serum contained significantly higher levels of IL-6 (P < 0.001), MMP-1 (P < 0.001), and MMP-13 (P < 0.05) compared to the peripheral blood of AMI. Serum IL-6 levels were significantly higher in the aspirated than in the peripheral blood in the patients hospitalized within 6 h and 6-12 h, but were similar in the aspirated and peripheral blood of the patients hospitalized 12-24 h after the onset of AMI. There were no differences between the aspirated serum and peripheral blood in the levels of interleukin-1beta and MMP-2.

CONCLUSIONS

The levels of MMP-1, MMP-13 and IL-6 were higher in the culprit coronary artery than in the peripheral blood. These factors appear to be involved in the early stage of AMI.

Thromboaspiration during acute myocardial infarction in a heart transplant patient

Each year, an estimated 10% of heart transplant recipients develop coronary allograft vasculopathy, an aggressive form of coronary artery disease that limits survival after transplantation. The pathologic characteristics of coronary allograft vasculopathy are not uniform and both the clinical importance and pathophysiological significance of thrombosis and vasospasm in this setting are not completely understood. Mechanical reperfusion is a better alternative to systemic thrombolysis in patients with acute myocardial infarction and thrombus removal before standard percutaneous coronary intervention improves coronary epicardial flow. We report the case of a 38-year-old male admitted to the emergency room of our hospital with acute inferior myocardial infarction complicated by cardiogenic shock. He underwent heart transplant because of ischemic cardiomyopathy. Coronary angiography showed acute coronary thrombosis of the circumflex coronary artery. Percutaneous coronary intervention with thrombus extraction was successfully attempted. This case represents an unusual clinical presentation and treatment of cardiac allograft vasculopathy.

Thrombus aspiration during primary percutaneous coronary intervention

BACKGROUND

Primary percutaneous coronary intervention (PCI) is effective in opening the infarct-related artery in patients with myocardial infarction with ST-segment elevation. However, the embolization of atherothrombotic debris induces microvascular obstruction and diminishes myocardial reperfusion.

METHODS

We performed a randomized trial assessing whether manual aspiration was superior to conventional treatment during primary PCI. A total of 1071 patients were randomly assigned to the thrombus-aspiration group or the conventional-PCI group before undergoing coronary angiography. Aspiration was considered to be successful if there was histopathological evidence of atherothrombotic material. We assessed angiographic and electrocardiographic signs of myocardial reperfusion, as well as clinical outcome. The primary end point was a myocardial blush grade of 0 or 1 (defined as absent or minimal myocardial reperfusion, respectively).

RESULTS

A myocardial blush grade of 0 or 1 occurred in 17.1% of the patients in the thrombus-aspiration group and in 26.3% of those in the conventional-PCI group (P<0.001). Complete resolution of ST-segment elevation occurred in 56.6% and 44.2% of patients, respectively (P<0.001). The benefit did not show heterogeneity among the baseline levels of the prespecified covariates. At 30 days, the rate of death in patients with a myocardial blush grade of 0 or 1, 2, and 3 was 5.2%, 2.9%, and 1.0%, respectively (P=0.003), and the rate of adverse events was 14.1%, 8.8%, and 4.2%, respectively (P<0.001). Histopathological examination confirmed successful aspiration in 72.9% of patients.

CONCLUSIONS

Thrombus aspiration is applicable in a large majority of patients with myocardial infarction with ST-segment elevation, and it results in better reperfusion and clinical outcomes than conventional PCI, irrespective of clinical and angiographic characteristics at baseline. (Current Controlled Trials number, ISRCTN16716833.)

Effect of intracoronary thrombectomy on 30-day mortality in patients with acute myocardial infarction

Insertion of intracoronary thrombectomy (ICT) devices, as a precedent to percutaneous coronary intervention (PCI), theoretically could have a beneficial effect on the outcome in patients with acute myocardial infarction. To examine whether ICT was associated with a lower 30-day mortality rate in patients with acute myocardial infarction, we studied 3,913 patients who underwent PCI within 24 hours after onset. A total of 990 patients (25.3%) were treated with ICT before PCI. The 30-day mortality rate was lower in the patients receiving ICT than in those without (3.7% vs 6.2%, p = 0.004), but this beneficial effect disappeared after adjustment for baseline characteristics (hazard ratio [HR] 0.658, p = 0.166). We also divided the patients into tertiles according to the Thrombolysis In Myocardial Infarction (TIMI) risk score. After adjustment for baseline characteristics, ICT was associated with a lower 30-day mortality rate in patients from the highest TIMI risk score tertile (HR 0.407, p = 0.029), but not in patients from the lower 2 tertiles. ICT was also an independent predictor of a lower 30-day mortality risk in patients aged > or =70 years (HR 0.239, p = 0.007), patients with diabetes mellitus (HR 0.275, p = 0.039), and those with stent implantation (HR 0.437, p = 0.034). In conclusion, in selected patients with high TIMI risk scores, an age > or =70 years, diabetes mellitus, or stenting, ICT is associated with a lower 30-day mortality rate.

Aspiration thrombectomy and primary percutaneous coronary intervention

How beneficial is the adjunctive use of thrombectomy devices in STEMI patients undergoing primary angioplasty?