Adjunctive mechanical devices to prevent distal embolization in patients undergoing mechanical revascularization for acute myocardial infarction: a meta-analysis of randomized trials

Case report: Unusual persistent hypotension and acute occlusion after peripheral paclitaxel balloon angioplasty

Background

Paclitaxel-coated balloon (PCB) angioplasty is a mainstream treatment for peripheral artery disease; however, the safety of PCB remains controversial.

Case presentation

We confirmed acute occlusion during PCB angioplasty in a patient with femoropopliteal artery occlusion. The occluded vessels were revascularized completely after endovascular medical therapy and bailout stenting angioplasty. Then, the patient experienced persistent post-procedure orthostatic hypotension (30 days) and received hydration and vasoactive agents with a target mean arterial blood pressure of 75–85 mmHg. The patient's blood pressure gradually recovered over the 30 days after the procedure, and there was no recurrence of symptomatic hypotension during the follow-up.

Conclusions

This rare complication is helpful to evaluate the safety of the PCB device.

Efficacy of Long Inflation Balloon Angioplasty for Acute Myocardial Infarction Due to Thrombotic Lesions

BACKGROUND

Distal embolism is a frequent complication in percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) due to thrombotic lesions. Distal embolism causes no reflow phenomenon, which leads to worse patient prognosis after AMI. There is no established treatment to prevent distal embolism in PCI for thrombotic lesions. The aim of this study is to investigate the usefulness of long inflation balloon angioplasty (LIBA) with perfusion balloon in PCI for AMI due to thrombotic lesions.

METHODS AND RESULTS

This is a case series study. We investigated 10 cases treated with LIBA for cases with massive thrombus remaining after thrombus aspiration therapy in primary PCI for acute myocardial infarction. We investigated the success rate of the procedure, residual stenosis rate, TIMI flow grade, TIMI frame count, and myocardial blush score in 10 cases of primary PCI with LIBA at our hospital. In all 10 cases, distal embolism was not observed by angiogram after LIBA. In 9 cases, residual stenosis was improved to less than 25% and the procedure was completed without a stent. Before PCI, all cases had TIMI flow grade 0, but in all 10 cases, TIMI flow grade 3 was obtained after PCI. The mean TIMI frame count was 19.6 ± 2.50 for RCA lesions and 27.5 ± 1.5 for LAD lesions. Regarding myocardial blush score, grade 3 was obtained in 8 cases and grade 2 was obtained in 2 cases.

CONCLUSION

LIBA using a perfusion balloon is a useful technique in thrombus lesion to prevent distal embolism.

Thrombus Embolisation: Prevention is Better than Cure

Thrombus embolisation complicating primary percutaneous coronary intervention in ST-elevation myocardial infarction is associated with an increase in adverse outcomes. However, there are currently no proven recommendations for intervention in the setting of large thrombus burden. In this review, we discuss the clinical implications of thrombus embolisation and angiographic predictors of embolisation, and provide an update of current evidence for some preventative strategies, both pharmacological and mechanical, in this setting.

Outcome of thrombus aspiration in STEMI patients: a propensity score-adjusted study

The use of thrombus aspiration (TA) prior to primary percutaneous coronary intervention (PPCI) has undergone a radical change in intervention guidelines. The clinical implications, however, are still under scrutiny. This study investigated the clinical effects and outcome of TA before PPCI in patients with ST-segment elevation myocardial infarction (STEMI). Overall 1027 patients with STEMI were analyzed in this retrospective, propensity score-adjusted, multicenter study. The primary endpoints were in-hospital and long-term mortality. There were 418 patients in the TA group and 609 in the conventional PPCI group. The in-hospital mortality rate was significantly higher in the TA group (8.7 vs. 5.0%; P = 0.03). During long-term follow-up [median follow-up duration 689 days (IQR 405-959)] the mortality rates were similar (TA 14.3%, conventional PPCI 15.0%; P = 0.85). Survival analysis for the complete observation period revealed no significant benefit of TA [hazard ratio (HR) 1.12; 97.5% CI 0.90-0.71; P = 0.63]. There were also no significant differences between the groups in the following secondary endpoints: composite of cardiovascular death and non-fatal reinfarction at discharge (P = 0.39), post-PPCI thrombolysis in myocardial infarction flow-grade-3 (P = 0.14), left ventricular ejection fraction (P = 0.47), and non-fatal reinfarction during follow-up (P = 0.17). Rehospitalization rate (1.82 vs. 10.3%; P < 0.0001) and Canadian Cardiovascular Society (CCS) grading (P = 0.02) during follow-up were significantly lower in the TA group. In our cohort the in-hospital mortality rate was significantly higher for TA patients, but during long-term follow-up the mortality rates did not differ. The incidence of rehospitalization and CCS grading were lower in the TA-treated patients.

The combination assessment of lipid pool and thrombus by optical coherence tomography can predict the filter no-reflow in primary PCI for ST elevated myocardial infarction

The usefulness of distal protection devices is still controversial. Moreover, there is no report on thrombus evaluation by using optical coherence tomography (OCT) for determining whether to use a distal protection device. The aim of the present study was to investigate the predictor of filter no-reflow (FNR) by using OCT in primary percutaneous coronary intervention (PCI) for ST-elevated acute myocardial infarction (STEMI).We performed preinterventional OCT in 25 patients with STEMI who were undergoing primary PCI with Filtrap. FNR was defined as coronary flow decreasing to TIMI flow grade 0 after mechanical dilatation.FNR was observed in 13 cases (52%). In the comparisons between cases with or without the FNR, the stent length, lipid pool length, lipid pool + thrombus length, and lipid pool + thrombus index showed significant differences. In multivariate analysis, lipid pool + thrombus length was the only independent predictor of FNR (OR 1.438, 95% CI 1.001 - 2.064, P < .05). The optimal cut-off value of lipid pool + thrombus length for predicting FNR was 13.1 mm (AUC = 0.840, sensitivity 76.9%, specificity 75.0%). Moreover, when adding the evaluation of thrombus length to that of lipid pool length, the prediction accuracy of FNR further increased (IDI 0.14: 0.019-0.25, P = .023).The longitudinal length of the lipid pool plus thrombus was an independent predictor of FNR and the prediction accuracy improved by adding the thrombus to the lipid pool. These results might be useful for making intraoperative judgment about whether filter devices should be applied in primary PCI for STEMI.

Impact of Distal Protection with Filter-Type Device on Long-term Outcome after Percutaneous Coronary Intervention for Acute Myocardial Infarction: Clinical Results with Filtrap®

Aim: Although distal embolization during percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) deteriorates cardiac function, whether distal protection (DP) can improve prognosis is still controversial. We investigated whether a filter-type DP device, Filtrap^®, could improve long-term outcomes after PCI for AMI.

Method: We studied 164 patients (130 men, mean age: 65.7 years) who underwent PCI. Patients were divided into two groups based on the use of Filtrap^®. The occurrence of congestive heart failure (CHF) and major adverse cardiac events (MACE) defined as cardiac death, recurrent AMI, and target vessel revascularization were compared.

Result: Between DP (n = 53, 41 men, mean age: 65.5 years) and non-DP (n = 111, 89 men, mean age: 65.8 years) groups, although there was significantly greater plaque area in the DP group than in the non-DP group, there were no significant differences in coronary reperfusion flow after PCI. Interestingly, patients with CHF in the non-DP group exhibited a higher CK level than those in the DP group. During a 2-year follow-up period, cumulative CHF was significantly lower in the DP group than in the non-DP group (log-rank p = 0.018), and there was no significant difference in the MACE rate (log-rank p = 0.238). The use of DP device could not predict MACE, but could predict CHF by multivariate analysis (odds ratio = 0.099, 95% CI: 0.02–0.42, p = 0.005).

Conclusion: These results demonstrate that favorable clinical outcomes could be achieved by the filter-type DP device in AMI, particularly in patients with CHF.

Morphological predictors for no reflow phenomenon after primary percutaneous coronary intervention in patients with ST-segment elevation myocardial infarction caused by plaque rupture

AIMS

Myocardial no reflow after percutaneous coronary intervention (PCI) is associated with poor outcome. Patients with ST-segment elevation myocardial infarction (STEMI) caused by plaque rupture are at high risk for no reflow. However, specific morphologic characteristics associated with no reflow are unknown in this population. The aim of this study is to identify the morphological characteristics of culprit plaques associated with no reflow in patients with STEMI caused by plaque rupture using both optical coherence tomography (OCT) and intravascular ultrasound (IVUS).

METHODS AND RESULTS

We enrolled 145 patients with STEMI who underwent both OCT and IVUS within 12 h of symptom onset. Among these patients, we excluded those with plaque erosion and calcified nodule and included 72 patients who had plaque rupture as an underlying mechanism for STEMI. Myocardial no reflow, defined as Thrombolysis in Myocardial Infarction flow grade 0-2 and/or myocardial blush grade 0-1 after PCI, was observed in 28 patients (38.9%). Onset to recanalization time was similar between the groups with and without no reflow. Receiver-operating curve analysis revealed OCT-derived lipid index > 3500 [area under curve (AUC) 0.77, P < 0.001] and IVUS-derived plaque burden > 81.5% (AUC 0.70, P = 0.002) were the best discriminators for myocardial no reflow.

CONCLUSION

No reflow occurred in nearly 40% of patients with STEMI caused by plaque rupture. Large lipid index and plaque burden were critical morphological discriminators between no reflow and normal flow.

Thrombus aspiration in acute myocardial infarction: concepts, clinical trials, and current guidelines

The pathogenesis that underlies acute myocardial infarction is complex and multifactorial. One of the most important components, however, is the role of thrombus formation following atherosclerotic plaque rupture, leading to sudden coronary occlusion and subsequent ischemia and infarction. Thrombus aspiration provides the opportunity of intracoronary clot extraction with the aim to improve coronary and myocardial perfusion, by reducing the risk of no-reflow secondary to distal embolization of thrombus. The utility of thrombus aspiration during primary percutaneous coronary intervention has been assessed in an increasing number of observational and randomized studies. This article reviews the contemporary data and provides insights into the validity of thrombus aspiration in the setting of acute myocardial infarction.

Sodium tanshinone IIA sulfonate ameliorates experimental coronary no-reflow phenomenon through down-regulation of FGL2

AIMS

The effects of sodium tanshinone IIA sulfonate (STS) on coronary no-reflow (CNR) relevant to microvascular obstruction (MVO) remain unknown. Studies had shown that fibrinogen-like protein 2 (FGL2) expressed in microvascular endothelial cells (MECs) is a key mediator in MVO. Thus, we aimed to elucidate the roles of STS in CNR and relations between STS and FGL2.

MAIN METHODS

Myocardial ischemia/reperfusion was selected to represent CNR model. The no-reflow zone and infarct area were assessed using Thioflavin S and TTC staining, and cardiac functional parameters were detected using echocardiography. Western blot was used to detected FGL2 level, fibrin level, protease-activated receptor-1 (PAR-1) activation and inflammation cells infiltration. FGL2 and inflammation cells were also identified by IHC. Microthrombus was detected by Carstairs' and MSB staining. We also detected the roles of STS on FGL2 expression, thrombin generation, phospho-Akt and NF-κB levels in MECs.

KEY FINDINGS

Upon treatment with STS in CNR model, the no-reflow and infarct areas decreased significantly and cardiac function improved. The FGL2 expression was inhibited by STS in vivo as well as in vitro with thrombin generation inhibition. In addition, STS up-regulates Akt phosphorylation and suppressed NF-κB expression in activated MECs. Furthermore, fibrin deposition, PAR-1 activation and inflammatory response were inhibited with STS administration in CNR model.

SIGNIFICANCE

Our results displayed a novel pharmacological action of STS on CNR. STS is able to ameliorate CNR through inhibition of FGL2 expression mediated by Akt and NF-κB pathways as well as prevention of MVO by suppressing fibrin deposition and inflammation.

Aspiration Thrombectomy for Treatment of ST-segment Elevation Myocardial Infarction: a Meta-analysis of 26 Randomized Trials in 11,943 Patients

INTRODUCTION AND OBJECTIVES

There is continued debate about the routine use of aspiration thrombectomy in patients with ST-segment elevation myocardial infarction. Our aim was to evaluate clinical and procedural outcomes of aspiration thrombectomy-assisted primary percutaneous coronary intervention compared with conventional primary percutaneous coronary intervention in patients with ST-segment elevation myocardial infarction.

METHODS

We performed a meta-analysis of 26 randomized controlled trials with a total of 11 943 patients. Clinical outcomes were extracted up to maximum follow-up and random effect models were used to assess differences in outcomes.

RESULTS

We observed no difference in the risk of all-cause death (pooled risk ratio = 0.88; 95% confidence interval, 0.74-1.04; P = .124), reinfarction (pooled risk ratio = 0.85; 95% confidence interval, 0.67-1.08; P = .176), target vessel revascularization (pooled risk ratio = 0.86; 95% confidence interval, 0.73-1.00; P = .052), or definite stent thrombosis (pooled risk ratio = 0.76; 95% confidence interval, 0.49-1.16; P = .202) between the 2 groups at a mean weighted follow-up time of 10.4 months. There were significant reductions in failure to reach Thrombolysis In Myocardial Infarction 3 flow (pooled risk ratio = 0.70; 95% confidence interval, 0.60-0.81; P < .001) or myocardial blush grade 3 (pooled risk ratio = 0.76; 95% confidence interval, 0.65-0.89; P = .001), incomplete ST-segment resolution (pooled risk ratio = 0.72; 95% confidence interval, 0.62-0.84; P < .001), and evidence of distal embolization (pooled risk ratio = 0.61; 95% confidence interval, 0.46-0.81; P = .001) with aspiration thrombectomy but estimates were heterogeneous between trials.

CONCLUSIONS

Among unselected patients with ST-segment elevation myocardial infarction, aspiration thrombectomy-assisted primary percutaneous coronary intervention does not improve clinical outcomes, despite improved epicardial and myocardial parameters of reperfusion.

A rare case of acute myocardial infarction with multivessel coronary artery ectasia successfully treated with percutaneous coronary intervention and systemic thrombolysis

Coronary artery ectasia (CAE) is defined as a coronary artery dilatation with a diameter ≥1.5 times greater than that of a normal adjacent artery. All 3 coronary vessels can be affected by CAE, but the incidence of multivessel CAE among patients undergoing coronary angiography is quite low. We herein report an extremely rare case of acute myocardial infarction due to massive thrombi in the giant right coronary artery with multivessel CAE. Thrombus aspiration during percutaneous coronary intervention may be limited in giant coronary artery cases, and systemic thrombolysis may be effective in patients with massive thrombi in the giant coronary artery.

A multistudy analysis investigating systematic differences in cardiovascular trial results between Europe and Asia

OBJECTIVE

To assess whether there are differences in the results of cardiovascular trials between Europe and Asia using data from an extensive collection of randomised controlled trials.

STUDY DESIGN AND SETTING

All meta-analyses containing randomised controlled trials (RCT's) for the treatment or prevention of cardiovascular diseases were searched for in The Cochrane Library (2000-2008) and MEDLINE (2005-2008). Analysis was then conducted within and over each meta-analysis which satisfied given criteria. Separate estimates of treatment effect were calculated for Europe and Asia in each meta-analysis and then compared. Estimates of a common inter-continental difference over all meta-analyses were also calculated and meta-regression was performed. This was performed for both fatal and non-fatal end points.

RESULTS

The literature search identified 59 meta-analyses that satisfied the inclusion criteria. After exclusion, the number of meta-analyses reporting greater effect sizes in Asia than in Europe was significantly more than would be expected by chance (fatal 12/14, p=0.013; non-fatal 23/32, p=0.020).

CONCLUSIONS

This study provides some evidence that for cardiovascular interventions treatment effect estimation differs between Europe and Asia, with respect to both fatal and non-fatal end points.

Noninfarct related artery embolic protection during primary PCI

A 66-year old man presented with antero-lateral STEMI. An ulcerated plaque and thrombus were seen in the proximal LAD. We were unable to pass a thrombectomy catheter down the LAD. To avoid embolisation of debris a Spider FX distal protection device was placed into the circumflex artery. Following stent implantation the patient developed chest pain with inferolateral ST depression. Thrombus was extracted from the circumflex artery within the distal protection device. Noninfract related artery distal protection during primary PCI may be an appropriate safeguard where thrombectomy is not possible in an infarct-related left coronary branch.

Catheter Aspiration after Every Stage during Primary Percutaneous Angioplasty; ADMIT Trial

We assess the epicardial and microcirculation flow characteristics, and clinical outcome by using catheter aspiration after each stage of primary percutaneous coronary intervention (PPCI). Conflicting data are reported regarding early and late benefit of using aspiration catheter in the initial phase PPCI. A total of 100 patients with ST-segment elevation acute myocardial infarction (STEMI) were included: 51 underwent PPCI without using an aspiration device (SA group) and 49 underwent PPCI by activating an aspiration catheter after each stage of procedure; wiring, ballooning and stenting, respectively (MA group). Thrombolysis in myocardial infarction (TIMI) flow grade, TIMI frame counts and myocardial blush grade (MBG) were evaluated in each group during every stage of procedure. Major adverse cardiac events were evaluated in the index hospitalization and during 30 and 180 days of follow-up. A TIMI flow grade 2-3 was more prevalent in the MA group compared with the SA group only after wiring: 65.9 versus 39.1% (p = 0.01), but TIMI frame counts were lower in the MA versus SA group throughout all procedural steps. MBG 2-3 was statistically higher in the MA group compared with the SA group mainly after wiring. After stenting there were no significant changes in both epicardial and microcirculation flow parameters. There were no significant differences between the groups in early and late clinical outcomes. Improved flow parameters were noticed in the MA group only by activating the aspiration device after wiring. This early advantage disappeared after stenting. The initial better flow characteristic in the MA group was not translated into a better early or late clinical outcome.

Comparison of the reperfusion efficacy of thrombus aspiration with and without distal protection during primary percutaneous coronary intervention in patients with acute ST-segment elevation myocardial infarction

We evaluated a hypothesis that thrombus aspiration with distal protection is superior to simple thrombus aspiration in patients treated with primary percutaneous coronary intervention (PCI). A total of 176 consecutive patients with ST-segment elevation myocardial infarction were enrolled in this study and assigned to either the thrombus aspiration group (A, n = 104) or the thrombus aspiration with distal protection group using a filter device system (A + DP, n = 72). We compared the angiographic reperfusion grade, left ventricular (LV) function, and clinical outcomes between the 2 groups. There were no significant differences in age, gender distribution, the onset-to-reperfusion time, the peak levels of creatine kinase, or 6-month mortality between the 2 groups. The rate of achieving a Thrombolysis In Myocardial Infarction flow grade of 3 and a myocardial blush grade of 3 was higher in the A + DP group than in the A group. Among the patients who underwent follow-up catheterization 6 months after PCI (A, n = 62; A + DP, n = 52), there were no significant differences in the LV end-diastolic volume index, LV end-systolic volume index, or LV ejection fraction between the 2 groups at the time of PCI or 6 months after PCI. In conclusion, thrombus aspiration with distal protection may be more effective in initially restoring the coronary blood flow than thrombus aspiration alone, although it may not be superior to thrombus aspiration in preventing LV remodeling or preserving the LV function in patients with ST-segment elevation myocardial infarction.

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.

Coronary reperfusion and clinical outcomes after thrombus aspiration during primary percutaneous coronary intervention: findings from the HORIZONS-AMI trial

OBJECTIVES

To assess the quality of coronary reperfusion and long-term clinical outcomes of patients enrolled in the HORIZONS-AMI trial according to the use of thrombus aspiration (TA).

BACKGROUND

The impact of manual TA on microvascular perfusion and clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (pPCI) is unsettled.

METHODS

In this retrospective, nonrandomized, subgroup analysis, the authors evaluated thrombolysis in myocardial infarction (TIMI) flow, tissue myocardial perfusion grade (TMPG), ST-segment resolution (STR), net adverse clinical events (NACE), and major adverse cardiac events (MACE) in patients undergoing pPCI with or without manual TA.

RESULTS

A total of 318 patients had pPCI with upfront TA, and 2,917 patients had pPCI without TA. Patients who had TA were more likely to have TIMI 0/1 flow at baseline (75.1% vs. 63.7%, P < 0.0001). There was no difference in the rates of final TIMI 3 flow (90.2% vs. 92.3%, P = 0.19) or dynamic TMPG 2-3 (77.4% vs. 76.4%, P = 0.68). STR ≥70% was similar in both groups at 60 minutes but higher in the TA group at discharge (71.8% vs. 64.6%, P = 0.02). After multivariable adjustment, TA did not predict MACE at 30 days (HR 0.96 [0.51-1.80], P = 0.90), 1 year (HR 1.03 [0.68-1.55], P = 0.89), or 3 years (HR 1.13 [0.86-1.48], P = 0.39). Stent thrombosis did not differ at 1 year or 3 years.

CONCLUSIONS

In STEMI patients undergoing pPCI, the use of manual TA was associated with improved STR at discharge, but not with any difference in final TIMI flow, TMPG, or MACE.

Comparison of Manual Thrombus Aspiration With Rheolytic Thrombectomy in Acute Myocardial Infarction

Background—

Manual thrombus aspiration (MTA) is completely ineffective in 30% of cases, and the high profiles of the catheters prevent their use in tortuous and calcified vessels. The rheolytic thrombectomy (RT) device has the potential for improved thrombus removal in acute myocardial infarction as compared with MTA. No data exist on the comparison between the 2 techniques.

Methods and Results—

Randomized study, including 80 acute myocardial infarction patients allocated to RT or MTA before infarct artery stenting. Primary end point of this study is residual thrombus burden by optical coherence tomography. Secondary end points are (1) residual thrombolysis in myocardial infarction thrombus grade; (2) postintervention thrombolysis in myocardial infarction flow and myocardial blush; (3) early ST-segment resolution; (4) percentage of malapposed stent struts at 6 months; (5) 6-month restenosis; and (6) 6-month major adverse cardiovascular events. All but 1 patient had residual thrombus after manual aspiration thrombectomy or RT. The number of optical coherence tomography quadrants containing thrombus in MTA arm was higher than in the RT arm, but this difference did not reach significance (median value 65 and 53, respectively; P =0.083). Large residual thrombus was more frequently revealed in the manual aspiration thrombectomy arm (patients with number of quadrants above the median value 60% in the manual aspiration thrombectomy arm and 37% in the RT arm, P =0.039). All markers of reperfusion were better in the RT arm. At 6 months, the percentage of malapposed stent struts in the MTA arm was higher than in the RT arm (2.7±4.5% and 0.8±1.6%, respectively; P =0.019).

Conclusions—

MTA or RT allows only incomplete removal of thrombus in patients with acute myocardial infarction. The primary end point of the study was not met. However, RT as compared with MTA seems to be more effective in thrombus removal and myocardial reperfusion.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT01281033.

Pharmacological and physical prevention and treatment of no-reflow after primary percutaneous coronary intervention in ST-segment elevation myocardial infarction

After successful primary percutaneous coronary intervention in ST-segment elevation myocardial infarction, adequate myocardial reperfusion is not achieved in up to 50% of patients. This phenomenon of no-reflow is associated with a poor in-hospital and long-term prognosis. Four main factors are thought to contribute to the occurrence of no-reflow: ischaemic injury; reperfusion injury; distal embolization; susceptibility of the microcirculation to injury. This review evaluates the literature, and in particular the clinical trials, concerned with pharmacological and physical methods for prevention and treatment of no-reflow. A number of drugs may improve no-reflow experimentally and clinically, but some have not yet been associated with conclusive improvements in clinical outcome. The complex interacting factors in no-reflow make it unlikely that any single agent will be effective for all patients. Confirmed methods known to be beneficial in the prevention of no-reflow (such as aspirin therapy, chronic statin therapy, blood glucose control, thrombus aspiration in patients with a high thrombus burden and ischaemic preconditioning) should be offered to patients as often as possible, to prevent and treat no-reflow.

No-Reflow Phenomenon

No-reflow is responsible for 40% of the primary percutaneous coronary intervention without complete myocardial reperfusion despite successful reopening of the infarct-related artery. This review describes the main pathophysiological mechanisms of no-reflow, its clinical manifestation, including the strong association with increased in-hospital mortality, malignant arrhythmias, and cardiac failure as well as the diagnostic methods. The latter ranges from simple angiographic thrombolysis in myocardial infarction grade score to more complex angiographic indexes, imaging techniques such as myocardial contrast echo or cardiac magnetic resonance, and surrogate clinical end points such as ST-segment resolution. This review also summarizes the strategies of prevention and treatment of no-reflow, considering the most recent studies results regarding medical therapy and devices.

Operator versus core laboratory assessment of angiographic reperfusion markers in patients undergoing primary percutaneous coronary intervention for ST-segment-elevation myocardial infarction

BACKGROUND

Thrombolysis In Myocardial Infarction (TIMI) flow and Myocardial Blush Grade (MBG) are important prognostic indicators before and after primary percutaneous coronary intervention (PCI) in ST-segment-elevation myocardial infarction; however, the concordance and relative prognostic utility of operator (Op) versus angiography core laboratory (ACL) assessed TIMI flow and MBG are unknown.

METHODS AND RESULTS

Baseline and final Op and ACL TIMI flow and MBG assessment were compared from the Harmonizing Outcomes with RevascularIZatiON and Stents in AMI trial in 3345 patients undergoing primary PCI using Cohen's κ coefficient. κ Was highest for pre-PCI TIMI flow (0.51, representing moderate agreement) and lowest for post-PCI MBG (0.20, representing fair agreement). Discordance between Op and ACL for final TIMI flow (0 to 2 versus 3) occurred in 12.9% of patients and for final MBG (0 to 1 versus 2 to 3) in 22.4%. Among 415 patients with final TIMI flow 0 to 2 by ACL, Op scoring was TIMI flow 3 in 267 (64.3%). Similarly, among 706 patients with final MBG 0 to 1 by ACL, 563 (79.7%) were classified as MBG 2 to 3 by Op. Post-PCI TIMI 3 flow and MBG 2 to 3 strongly correlated with 3-year survival, as assessed by both Op and ACL (P<0.0001). Mortality was intermediate in patients in whom ACL and Op were discordant, without marked prognostic differences between the discordant groups.

CONCLUSIONS

Op and ACL assessment of angiographic markers of reperfusion in ST-segment-elevation myocardial infarction demonstrates fair to moderate agreement. Op tended to favorably grade unfavorable ACL results. Nonetheless, both Op and ACL assessment of reperfusion strongly inform prediction of 3-year mortality.

Current debate on the role of embolic protection devices

The role of embolic protection devices (EPDs) during percutaneous arterial revascularization is still debated. This article discusses the use, the limitations, and issues of the variety of EPDs in different vascular beds, with a particular focus on the lower extremity arterial interventions.

Relationship between angiographic dynamic and densitometric assessment of myocardial reperfusion and survival in patients with acute myocardial infarction treated with primary percutaneous coronary intervention: the harmonizing outcomes with revascularization and stents in AMI (HORIZONS-AMI) trial

OBJECTIVES

We evaluated 2 different methods of assessing tissue myocardial perfusion (TMP) and its impact on long-term mortality in patients with ST-segment elevation myocardial infarction (STEMI).

BACKGROUND

Although primary percutaneous coronary intervention restores brisk epicardial flow in approximately 90% of patients with STEMI, normal TMP is less commonly achieved. Tissue myocardial perfusion has been shown to correlate mostly with early clinical outcomes.

METHODS

We analyzed the outcomes of 3,267 patients in the HORIZONS-AMI study according to final TMP, assessed by angiographic dynamic (Dyn) and densitometric (Den) methods. Multivariable analysis was performed to identify the independent influence of TMP grade 2/3 on late survival.

RESULTS

Dyn TMP 2/3 was achieved in 2,600 patients (79.6%), whereas Den TMP 2/3 was achieved in 2,483 (76.0%). Mortality was significantly lower in those with Dyn TMP 2/3 compared with TMP 0/1 at 30 days (1.1% vs 6.9%, P < .0001) and at 3 years (5.1% vs 11.2%, P < .0001). Similar results were obtained with Den TMP. Dyn TMP 2/3 was an independent predictor of mortality at both time points (HR 0.21, 95% CI 0.12-0.37, P < .0001 and HR 0.53, 95% CI 0.38-0.73, P < .0001, respectively), as was Den TMP. Survival was comparable in patients with TMP 2 and TMP 3.

CONCLUSIONS

Angiographic TMP can be assessed reliably using either Dyn or Den methods and is a powerful, independent predictor of early and late mortality after primary percutaneous coronary intervention in STEMI.

Clinical and angiographic predictors and prognostic value of failed thrombus aspiration in primary percutaneous coronary intervention

OBJECTIVES

This study sought to investigate which factors are associated with failure of thrombus aspiration (TA) and if this has prognostic implications.

BACKGROUND

The pathophysiological mechanism and clinical benefit of TA during primary percutaneous coronary intervention for acute ST-segment elevation myocardial infarction is still in debate.

METHODS

Between August 2001 and October 2007, TA was attempted in 1,399 patients. Failure of TA was defined as the inability to reach and/or cross the occlusion with the aspiration catheter for effective thrombus removal. In addition, we analyzed patients in which no material could be obtained. We examined baseline clinical and angiographic variables related to failure of TA or to the lack of aspirate. Follow-up on vital status was obtained at 1 year.

RESULTS

In 144 (10.3%) patients, the aspiration catheter failed to cross the lesion. After multivariable adjustment, marked proximal tortuosity (odds ratio [OR]: 2.88, 95% confidence interval [CI]: 1.92 to 4.31, p < 0.001), the presence of a calcified lesion (OR: 2.70, 95% CI: 1.77 to 4.13, p < 0.001), and a bifurcation lesion (OR: 1.97, 95% CI: 1.15 to 3.37, p = 0.013) were independent predictors of failed TA. Age over 60 years and the circumflex as infarct-related artery were associated with the lack of aspirate. Mortality rates at 1 year were 6.2% in patients with failed TA and 6.4% with successful TA (hazard ratio: 0.98, 95% CI: 0.49 to 1.95, p = 0.95).

CONCLUSIONS

The presence of marked proximal tortuosity of the infarct-related artery, a calcified lesion, and a bifurcation lesion are independent predictors of failure of thrombus aspiration. We found that unsuccessful TA did not affect 1-year mortality.

Management of the no-reflow phenomenon

The lack of reperfusion of myocardium after prolonged ischaemia that may occur despite opening of the infarct-related artery is termed "no reflow". No reflow or slow flow occurs in 3-4% of all percutaneous coronary interventions, and is most common after emergency revascularization for acute myocardial infarction. In this setting no reflow is reported to occur in 30% to 40% of interventions when defined by myocardial perfusion techniques such as myocardial contrast echocardiography. No reflow is clinically important as it is independently associated with increased occurrence of malignant arrhythmias, cardiac failure, as well as in-hospital and long-term mortality. Previously the no-reflow phenomenon has been difficult to treat effectively, but recent advances in the understanding of the pathophysiology of no reflow have led to several novel treatment strategies. These include prophylactic use of vasodilator therapies, mechanical devices, ischaemic postconditioning and potent platelet inhibitors. As no reflow is a multifactorial process, a combination of these treatments is more likely to be effective than any of these alone. In this review we discuss the pathophysiology of no reflow and present the numerous recent advances in therapy for this important clinical problem.

Stenting of complex lesions: an overview

Contemporary management of coronary artery disease relies increasingly on percutaneous techniques combined with medical therapy. Although percutaneous coronary intervention (PCI) can be performed successfully in most lesions, several difficult lesion subsets continue to present unique technical challenges. These complex lesions may be classified according to anatomic criteria, including extensive calcification, thrombus, and chronic occlusions, or by location, such as bifurcations, saphenous vein grafts and unprotected left main. PCI of these lesions often requires novel devices, such as drug-eluting stents, hydrophilic guidewires, distal protection balloons or filters, thrombectomy catheters, rotational atherectomy, and cutting balloons. An integrated approach that combines these devices with specialized techniques and adjunctive pharmacologic agents has greatly improved PCI success rates for these complex lesions.

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.

Thrombus Aspiration in ST-Elevation myocardial infarction in Scandinavia (TASTE trial). A multicenter, prospective, randomized, controlled clinical registry trial based on the Swedish angiography and angioplasty registry (SCAAR) platform. Study design and rationale

BACKGROUND

In ST-elevation myocardial infarction (STEMI), distal embolization of thrombus material often precludes restoration of normal coronary artery flow. Small-scaled studies have demonstrated that intracoronary thrombus aspiration improves flow and myocardial perfusion, but only one larger randomized single-center study has suggested a survival benefit. Thrombus aspiration is widely used in clinical practice and is recommended by international guidelines despite limited evidence.

METHODS/DESIGN

The Thrombus Aspiration in ST-Elevation myocardial infarction in Scandinavia is a multicenter, prospective, randomized, controlled, clinical open-label trial based on the Swedish angiography and angioplasty registry (SCAAR) platform with blinded evaluation of end points. A total of 5,000 patients with STEMI undergoing primary percutaneous coronary intervention (PCI) will randomly be assigned either to conventional PCI or to thrombus aspiration followed by PCI. SCAAR will be used as the platform for randomization, allowing a broad population of all-comers in the registry network to be enrolled. All follow-up will also be done in SCAAR and other national registries. The primary end point is time to all-cause death at 30 days.

DISCUSSION

The Thrombus Aspiration in ST-Elevation myocardial infarction in Scandinavia trial is the largest trial to date to evaluate the effect of thrombus aspiration on death following PCI in patients with STEMI. We propose the term randomized clinical registry trial to describe the novel entity of using an online national registry as platform for case records, randomization, and follow-up.

Thrombus aspiration followed by direct stenting: a novel strategy of primary percutaneous coronary intervention in ST-segment elevation myocardial infarction. Results of the Polish-Italian-Hungarian RAndomized ThrombEctomy Trial (PIHRATE Trial)

BACKGROUND

Previous studies with thrombectomy showed different results, mainly due to use of thrombectomy as an additional device not instead of balloon predilatation. The aim of the present study was to assess impact of aspiration thrombectomy followed by direct stenting.

METHODS

Patients with ST elevation myocardial infarction (STEMI) <6 hours from pain onset and occluded infarct-related artery in baseline angiography were randomized into aspiration thrombectomy followed by direct stenting (TS, n = 100) or standard balloon predilatation followed by stent implantation (n = 96). The primary end point of the study was the electrocardiographic ST-segment elevation resolution >70% (STR > 70%) 60 minutes after primary angioplasty (percutaneous coronary intervention [PCI]). Secondary end points included angiographic myocardial blush grade (MBG) after PCI, combination of STR > 70% immediately after PCI and MBG grade 3 (optimal myocardial reperfusion), Thrombolysis In Myocardial Infarction flow after PCI, angiographic complications, and in-hospital major adverse cardiac events.

RESULTS

Aspiration thrombectomy success rate was 91% (crossing of the lesion with thrombus reduction and flow restoration). There was no significant difference in STR ≥ 70% after 60 minutes (53.7% vs 35.1%, P = .29). STR > 70% immediately after PCI (41% vs 26%, P < .05), MBG grade 3 (76% vs 58%, P < .03), and optimal myocardial reperfusion (35.1% vs 11.8%, P < .001) were more frequent in TS. There was no difference in between the groups in 6-month mortality (4% vs 3.1%, P = .74) and reinfarction rate (1% vs 3.1%, P = .29).

CONCLUSIONS

Aspiration thrombectomy and direct stenting is safe and effective in STEMI patients with early presentation (<6 hours). The angiographic parameters of microcirculation reperfusion and ECG ST-segment resolution directly after PCI were significantly better in thrombectomy group despite the lack of the difference in ST-segment resolution 60 minutes after PCI.

Comparison of AngioJet rheolytic thrombectomy before direct infarct artery stenting with direct stenting alone in patients with acute myocardial infarction. The JETSTENT trial

OBJECTIVES

The aim of this study was to determine whether rheolytic thrombectomy (RT) before direct infarct artery stenting as compared with direct stenting (DS) alone results in improved myocardial reperfusion and clinical outcome in patients with acute myocardial infarction.

BACKGROUND

The routine removal of thrombus before infarct artery stenting is still a matter of debate.

METHODS

This is a multicenter, international, randomized, 2-arm, prospective study. Eligible patients were patients with acute myocardial infarction, angiographic evidence of thrombus grade 3 to 5, and a reference vessel diameter ≥2.5 mm. Coprimary end points were early ST-segment resolution and (99m)Tc-sestamibi infarct size. An α value = 0.05 achieved by both coprimary surrogate end points or an α value = 0.025 for a single primary surrogate end point would be considered evidence of statistical significance. Other surrogate end points were Thrombolysis In Myocardial Infarction (TIMI) flow grade 3, corrected TIMI frame count, and TIMI grade 3 blush. Clinical end points were a composite of major adverse cardiovascular events at 1, 6, and 12 months.

RESULTS

From December 2005 to September 2009, 501 patients were randomly allocated to RT before DS or to DS alone. The ST-segment resolution was more frequent in the RT arm as compared with the DS alone arm: 85.8% and 78.8%, respectively (p = 0.043), while no difference between groups were revealed in the other surrogate end points. The 6-month major adverse cardiovascular events rate was 11.2% in the thrombectomy arm and 19.4% in the DS alone arm (p = 0.011). The 1-year event-free survival rates were 85.2 ± 2.3% for the RT arm, and 75.0 ± 3.1% for the DS alone arm (p = 0.009).

CONCLUSIONS

Although the primary efficacy end points were not met, the results of this study support the use of RT before infarct artery stenting in patients with acute myocardial infarction and evidence of coronary thrombus. (AngioJet Rheolytic Thrombectomy Before Direct Infarct Artery Stenting in Patients Undergoing Primary PCI for Acute Myocardial Infarction [JETSTENT]; NCT00275990).