A new approach of primary angioplasty for ST-elevation acute myocardial infarction based on minimalist immediate mechanical intervention

Safety of conservative management for non-stenotic culprit lesions in STEMI patients treated with a two-step reperfusion strategy: a SUPER-MIMI sub-study

Background

In the observational SUPER-MIMI study, a minimalist immediate mechanical intervention (MIMI) technique-which involves restoring blood flow in the acute phase and postponing stenting-was shown to be safe and effective among patients with a high thrombotic burden after ST-segment elevation myocardial infarction (STEMI). We aim to assess whether a non-stenting strategy after a SUPER-MIMI strategy was safe at 4-year follow-up in patients enrolled in the SUPER-MIMI study who were not stented.

Methods

This prospective cohort study assessed the long-term outcomes of a subgroup of patients included in the SUPER-MIMI study.

Results

Among the 155 patients enrolled in the SUPER-MIMI study, 57 patients (36.8%) benefited from a conservative management (without stenting or balloon angioplasty) and were included in the current substudy. The mean duration of follow-up was 4.1±1.0 years. Four patients (7.0%) presented definite culprit lesion re-thrombosis, all of which occurred in the right coronary artery. The re-thrombosis rate appeared to be higher among patients with larger vessels: 2.9%, 8.3%, and 28.6% in arteries with diameters of 3-<4, 4-<5, and ≥5 mm, respectively. The overall rate of target lesion revascularization was 10.5%. There was one cardiac death and three rehospitalizations for heart failure. Overall, 82.5% of patients remained event free at a mean of 4.1±1.0 years.

Conclusions

Conservative management of non-stenotic culprit lesions after a SUPER-MIMI strategy was associated with a high rate of re-thrombosis, particularly in patients with large coronary arteries.

[Our enemy : the clot. Coronary thrombosis : strategy and therapeutic arsenal]

Intra coronary thrombus is  frequently encountered during acute coronary syndromes revascularisation procedures. It can also be encountered during angioplasty procedures in a stable angina context, although at a much lesser frequency.In both situations, it harbors a risk of poor angiographic result and poor prognosis. Intracoronnary thrombus may cause coronary occlusion at the angioplasty site or distal embolic  flow obstruction. Per procedure thrombus prevention rests on an prior optimal anti thrombotic treatment and in some circumstances the choice to defer the revascularisation procedure in the complex high risk setting. Treating the initiated thrombus remains controversial concerning thrombectomy and GPIIBIIIa inhibitors which are still in use in common practice. No reflow phenomenon is a particularly complex setting during cornary angioplasties, partially but not solely related to a thrombotic complication. It's treatment remains unclear in the absence of related oriented studies.The current mechanical and pharmacological antithrombotic therapies must remain common practice and used appropriately as of the clinical and angiographic setting, until further scientific outbrakes.

Stenting deferral in primary percutaneous coronary intervention: exploring benefits and suitable interval in heavy thrombus burden

BACKGROUND

Deferred stenting, despite being successful in early studies, showed no benefit in recent trials. However, these trials were testing routine deferral; not in patients with heavy thrombus burden.

RESULTS

This is a prospective, Randomized Clinical Trial that included 150 patients who presented with STEMI, patients were allocated into three equal groups after the coronary angiography ± primary intervention and before stenting of the culprit lesion; group (A) included 50 patients with early deferral of stenting, group (B) included 50 patients with late deferral and group (C) included 50 patients with immediate stenting. No-reflow was significantly higher in group C, while Final TIMI flow grade 3 and MBG grade 3 were significantly higher in group A and B than group C; p = 0.019 and < 0.001 respectively, with no significant difference between groups A and B, only the thrombus resolution in group B was significantly higher than group A; p < 0.001. Finally, 6-months, over-all MACE was significantly higher in group C (34.7% vs. 14.6% and 16.3%, p = 0.029).

CONCLUSIONS

Stent deferral was proved to be better than immediate stenting after recanalization of IRA, in achieving TIMI III flow, reducing risk of 6 months MACE, and restoration of myocardial function in a subset of STEMI patients presenting with large thrombus burden. While, no significant difference was found between both deferral times in final TIMI flow, or clinical outcomes.

Delayed endovascular surgery in patients with acute ST-segment elevation myocardial infarction due to massive culprit arterial thrombosis in the prevention of slow/no-reflow phenomenon

Aim. To assess whether delayed coronary artery stenting (CAS) can reduce the slow/no-reflow incidence in patients with ST-segment elevation myocardial infarction (STEMI) and massive thrombosis (TTG ≥3) of the infarct-related coronary artery (IRCA) compared with immediate CAS within primary PCI.

Material and methods. Out of 3651 primary PCIs performed for acute STEMI in the period from January 2016 to May 2020 at the Mytishchi City Clinical Hospital, the retrospective analysis included 105 patients with massive IRCA thrombosis (TTG ≥3). The patients were divided into two groups: first group (n=55) — delayed CAS, second group (n=50) — immediate CAS. In the immediate CAS group, the PCI procedure ended with routine stent implantation, and in the delayed CAS group, stent implantation was delayed for at least 5 days.

Results. In the delayed CAS group in comparison with immediate one, the slow/no-reflow phenomenon developed much less frequently in the form of a significant increase in the prevalence of TIMI 3 flow, better myocardial perfusion of myocardial blush grade (MBG) 2-3 (81,8 vs 64%; odds ratio (OR) 2,53; p=0,039) and ST segment resolution ≥70% (87,3% vs 58%; OR 4,97; p=0,001).

Conclusion. Delayed CAS in patients with STEMI with massive thrombosis (TTG ≥3) of IRCA reduces the risk of slow/no-reflow phenomenon and can be considered as a possible alternative treatment vs immediate CAS, provided that stable coronary flow is restored before TIMI 3.

Deferred Stenting for Heavy Thrombus Burden During Percutaneous Coronary Intervention for ST-Elevation MI

Patients with ST-elevation MI (STEMI) usually have a huge thrombus burden in the infarct-related artery. Stenting may lead to high chances of the slow-flow/no-reflow phenomenon that leads to periprocedural MI and adverse cardiovascular events. Deferred stenting may be beneficial in this situation as the thrombus burden will reduce, mitigating the slow-flow/no-reflow phenomenon. However, routine deferral of stenting in patients with STEMI has not been found to be beneficial, but when the patient is properly selected, deferred stenting has the potential for reducing the final infarct size. The authors report the safety and feasibility of deferred stenting after 5 days of prolonged anticoagulation in a 45-year-old smoker with STEMI who had a large thrombus load shown on an angiogram. They review the registries, trials and meta-analyses on deferred stenting in the literature and analyse the benefits and harms of the strategy. They also propose an algorithm for applying a strategy for deferred stenting in clinical practice based on the available data.

Effectiveness of deferred coronary artery stenting in the prevention of no-reflow in patients with acute ST-segment elevation myocardial infarction

It is known that even in spite of timely revascularization of the infarct-related artery, the myocardium in some patients remains hypoperfused. This condition is known as the no-reflow phenomenon, which is associated with an unfavorable prognosis. The systematic review is devoted to the effectiveness of deferred stenting in noreflow prevention. In patients with severe thrombosis, the two-stage revascularization technique is very promising. It is a primary intervention in the form of aspiration thrombectomy and/or balloon angioplasty followed by stenting after a certain period of time. This interval represents a certain therapeutic space, which allows various drugs to act resulting in reduction of blood clot size and risk of procedure-related distal embolization.

Predictors of suboptimal coronary blood flow after primary angioplasty and its implications on short-term outcomes in patients with acute anterior STEMI

BACKGROUND

Suboptimal coronary blood flow after primary percutaneous coronary intervention (PCI) is a complex multifactorial phenomenon. Although extensively studied, defined modifiable risk factors and efficient management strategy are lacking. This study aims to determine the potential causes of suboptimal flow and associated impact on 30-day outcomes in patients presenting with anterior ST-elevation myocardial infarction (STEMI).

METHODS

We evaluated a total of 1104 consecutive patients admitted to our hospital from January 2016 to December 2018 with the diagnosis of anterior wall STEMI who had primary PCI.

RESULTS

Overall, 245 patients (22.2%) had final post-PCI TIMI flow ≤2 in the LAD (suboptimal flow group) and 859 (77.8%) had final TIMI-3 flow (optimal flow group). The independent predictors of suboptimal flow were thrombus burden grade (Odds ratio (OR) 1.848; p < 0.001), age (OR 1.039 per 1-year increase; p < 0.001), low systolic blood pressure (OR 1.017 per 1 mmHg decrease; p < 0.001), total stent length (OR 1.021 per 1 mm increase; p < 0.001), and baseline TIMI flow ≤1 (OR 1.674; p = 0.018). The 30-day rates of major adverse cardiovascular events (MACE) and cardiac mortality were significantly higher in patients with TIMI flow ≤2 compared to those with TIMI-3 flow (MACE: adjusted risk ratio [RR] 2.021; P = 0.025, cardiac mortality: adjusted RR 2.931; P = 0.031).

CONCLUSION

Failure to achieve normal TIMI-3 flow was associated with patient-related (age) and other potentially modifiable risk factors (thrombus burden, admission systolic blood pressure, total stent length, and baseline TIMI flow). The absence of final TIMI-3 flow carried worse short-term clinical outcomes.

Immediate vs Delayed Stenting in ST-Elevation Myocardial Infarction: Rationale and Design of the International PRIMACY Bayesian Randomized Controlled Trial

BACKGROUND

Primary percutaneous coronary intervention is used to restore blood flow in the infarct-related coronary artery, followed by immediate stenting to prevent reocclusion. Stents implanted in thrombus-laden arteries cause distal embolization, which paradoxically impairs myocardial reperfusion and ventricular function. Whether a strategy of delayed stenting improves outcomes in patients with acute ST-elevation myocardial infarction (STEMI) is uncertain.

METHODS

The Primary Reperfusion Secondary Stenting (PRIMACY) is a Bayesian prospective, randomized, open-label, blinded end point trial in which delayed vs immediate stenting in patients with STEMI were compared for prevention of cardiovascular death, nonfatal myocardial infarction, heart failure, or unplanned target vessel revascularization at 9 months. All participants were immediately reperfused, but those assigned to the delayed arm underwent stenting after an interval of 24 to 48 hours. This interval was bridged with antithrombin therapy to reduce thrombus burden. In the principal Bayesian hierarchical random effects analysis, data from exchangeable trials will be combined into a study prior and updated with PRIMACY into a posterior probability of efficacy.

RESULTS

A total of 305 participants were randomized across 15 centres in France and Canada between April 2014 and September 2017. At baseline, the median age of participants was 59 years, 81% were male, and 3% had a history of percutaneous coronary intervention. Results from PRIMACY will be updated from the patient-level data of 1568 participants enrolled in the Deferred Stent Trial in STEMI (DEFER; United Kingdom), Minimalist Immediate Mechanical Intervention (MIMI; France), Danish Trial in Acute Myocardial Infarction-3 (DANAMI-3; Denmark), and Impact of Immediate Stent Implantation Versus Deferred Stent Implantation on Infarct Size and Microvascular Perfusion in Patients With ST Segment-Elevation Myocardial Infarction (INNOVATION, South Korea) trials.

CONCLUSIONS

We expect to clarify whether delayed stenting can safely reduce the occurrence of adverse cardiovascular end points compared with immediate stenting in patients with STEMI.

Optimal strategy of primary percutaneous coronary intervention for acute myocardial infarction due to unprotected left main coronary artery occlusion (OPTIMAL): study protocol for a randomised controlled trial

BACKGROUND

Primary percutaneous coronary intervention (PCI) for patients presenting with acute myocardial infarction (AMI) caused by left main coronary artery occlusion is associated with significantly higher mortality and risks of major adverse cardiovascular events. Deferred stent implantation may improve prognosis of primary PCI by reducing distal embolization and no-reflow phenomenon. There is no randomized clinical trial focusing on the effect and outcome of deferred stent implantation on primary PCI for left main coronary artery occlusion in contrast with conventional strategy.

METHODS

The Optimal Strategy of Primary Percutaneous Coronary Intervention for Acute Myocardial Infarction due to Unprotected Left Main Coronary Artery Occlusion (OPTIMAL) study (ClinicalTrials.gov Identifier: NCT03282773) is an open-label, randomized, multicenter clinical trial in which 480 patients presenting with AMI caused by left main coronary artery occlusion recruited from 30 hospitals in mainland China will be randomly assigned 1:1 to immediate stenting or deferred stenting (scheduled 4-10 days after primary angioplasty) groups. The primary endpoint is a composite of all-cause mortality or recurrent myocardial infarction at 30 days after randomization. The secondary outcomes include all-cause mortality, cardiac death, recurrent myocardial infarction, and unplanned target vessel revascularization at 30 days, 6 months, and 12 months.

DISCUSSION

The OPTIMAL study is designed to compare the clinical performance of deferred stenting with that of immediate stenting for AMI caused by left main coronary artery occlusion.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03282773 . Registered on 10 September 2017.

Stenting in Primary Percutaneous Coronary Intervention for Acute ST-Segment Elevation Myocardial Infarction

The treatment of ST-segment elevation myocardial infarction (STEMI) has advanced dramatically over the past 30 years since the introduction of reperfusion therapies, such that mechanical reperfusion with primary percutaneous coronary intervention is now the standard of care. With STEMI, as with other forms of acute coronary syndrome, stent deployment in culprit lesions is the dominant form of reperfusion in the developed world and is supported by contemporary guidelines. However, the precise timing of stenting and the extent to which both culprit and non-culprit lesions should be treated continue to be active areas of study. In this review, we revisit key data that support the use of mechanical reperfusion therapy in STEMI patients and explore the optimal timing for and extent of stent implantation in this complex patient group. We also review data surrounding the deleterious effects of untreated residual myocardial ischemia, the importance of complete revascularization, and the recent data exploring culprit-only versus multivessel stenting in the STEMI setting.

Examination of the appropriate timing of reperfusion therapy for recent myocardial infarction: a Japanese single-center retrospective study

BACKGROUND

The various guidelines clearly mention the treatment strategies for in patient of acute myocardial infarction (MI) presenting more than 24h from symptom onset (recent myocardial infarction, RMI). However, the appropriate timing of reperfusion for RMI is unclear.

METHODS

We retrospectively evaluated 525 consecutive MI patients who underwent percutaneous coronary intervention (PCI) in our hospital between January 2008 and December 2012.

RESULTS

Sixty RMI patients were more frequently associated with cardiac complications such as myocardial rupture (3.3% vs. 0%; p<0.01), ventricular septal rupture (3.3% vs. 0.4%; p<0.05), and congestive heart failure (15% vs. 2.6%; p<0.001) than 272 consecutive ST-elevation myocardial infarction (STEMI) patients. Of the 60 RMI patients, 33 (55.0%) underwent PCI within 7days (early-PCI group) and 27 (45.0%) underwent PCI after 7days (late-PCI group). Left ventricular ejection fraction measured by echocardiography at second hospital day was similar between the groups. The early-PCI group was more significantly associated with cardiogenic shock and heart failure and more frequently required intra-aortic balloon pumping (24.2% vs. 3.7%; p<0.05) than the late-PCI group. There were no significant differences in 30-day mortality, cardiac complications, and major cardiac events during long-term follow-up (12-36 months) between the groups.

CONCLUSION

RMI patients had a higher incidence of cardiac complications than AMI patients. Clinical outcomes were similar between patients undergoing early revascularization and those undergoing late revascularization, although the former group included a higher proportion of patients with severe cardiac failure.

Mechanical strategies to enhance myocardial salvage during primary percutaneous coronary intervention in patients with STEMI

Primary percutaneous coronary intervention (PPCI) has become the mainstay of reperfusion therapy in patients with ST-segment elevation myocardial infarction (STEMI). Despite timely reperfusion by PPCI and restoration of epicardial blood flow in up to 95% of patients, tissue reperfusion remains suboptimal in a sizeable proportion of patients with STEMI. Over the years mechanical and pharmacological strategies to enhance myocardial salvage during PPCI have been developed and used in patients with STEMI. The most common mechanical strategies used in the setting of PPCI include: coronary stenting, direct stenting, mesh-covered stents, self-expanding stents, deferred stenting, thrombectomy, distal protection devices, intra-aortic balloon pumping, left ventricular assist devices and ischaemic conditioning. These strategies are thought to enhance myocardial salvage via improving acute procedural success, attenuation of distal embolisation, microvascular obstruction and reperfusion injury, and providing haemodynamic support. Coronary (direct) stenting is almost the default approach of reperfusion during PPCI procedures. Evidence on the use of mesh-covered stents, self-expanding stents, deferred stenting or left ventricular assist devices is scant and their use in the setting of PPCI remains limited. Mechanical thrombectomy, distal protection devices or routine intra-aortic balloon counterpulsation seem to offer no clinical benefit when used in the setting of PPCI. Although manual aspiration may improve indices of tissue reperfusion, recent research showed no clinical benefit of routine use of this strategy in patients with STEMI undergoing PPCI. Ischaemic conditioning, although promising, remains at an investigational stage and needs further research.

Deferred Versus Immediate Stenting in Patients With ST-Segment Elevation Myocardial Infarction: A Systematic Review and Meta-Analysis

Background

A number of studies have evaluated the efficacy of deferred stenting vs immediate stenting in patients with ST‐segment elevation myocardial infarction, but the findings were not consistent across these studies. This meta‐analysis aims to assess optimal treatment strategies in patient with ST‐segment elevation myocardial infarction.

Methods and Results

We searched the PubMed, EMBASE, and the Cochrane Library for studies that assessed deferred vs immediate stenting in patients with ST‐segment elevation myocardial infarction. Nine studies including 1456 patients in randomized controlled trials and 719 patients in observational studies were included in the meta‐analysis. No significant differences were observed in the incidence of no‐ or slow‐reflow between deferred stenting and immediate stenting in randomized controlled trials (odds ratio [OR] 0.51, 95%CI 0.17‐1.53, P=0.23, I²=70%) but not in observational studies (OR 0.13, 95%CI 0.06‐0.31, P<0.0001, I²=0%). Deferred stenting was associated with an increase in long‐term left ventricular ejection fraction (weighted mean difference 1.90%, 95%CI 0.77‐3.03, P=0.001, I²=0%). No significant differences were observed in the rates of major adverse cardiovascular events (OR 0.53, 95%CI 0.27‐1.01, P=0.06 [randomized OR 0.98, 95%CI 0.73‐1.30, P=0.87, I²=0%; nonrandomized OR 0.30, 95%CI 0.15‐0.58, P=0.0004, I²=0%]), major bleeding (OR=0.1.61, 95%CI 0.70‐3.69, P=0.26, I²=0%), death (OR=0.78, 95%CI 0.53‐1.15, P=0.22, I²=0%), MI (OR=0.97, 95%CI 0.34‐2.78, P=0.96, I²=35%) and target vessel revascularization (OR 0.97, 95%CI 0.40‐2.37, P=0.95, I²=24%), between deferred and immediate stenting.

Conclusions

Compared with immediate stenting, a deferred‐stenting strategy did not reduce the occurrence of no‐ or slow‐reflow, death, myocardial infarction, or repeat revascularization compared with immediate stenting in patients with ST‐segment elevation myocardial infarction, but showed an improved left ventricular function in the long term.

Primary angioplasty: Effect of deferred stenting on stent size

BACKGROUND

Primary angioplasty with immediate stenting (IS) is the gold standard for ST-segment elevation myocardial infarction (STEMI). Deferred stenting (DS) has been proposed to limit periprocedural complications, and may influence stent size because of thrombus and spasm alleviation.

AIM

We sought to study the effect of DS on stent size.

METHODS

Over the study period, 258 patients underwent primary angioplasty for STEMI (DS, n=84; IS, n=174). An informative coronary angiogram run - i.e. allowing for proper lesion analysis - was selected and anonymized by an independent operator. Two experienced operators randomly analysed these runs, and proposed stent dimensions after having measured vessel diameter and lesion length by quantitative coronary analysis. The primary objective was the variation in stent size between the two coronary angiograms.

RESULTS

The median delay between the two coronary angiograms was 2 days. Overall, the stent length was shorter (-1.64mm; P=0.030) and its diameter was larger (+0.13mm; P<0.001) during the second coronary angiogram, especially in the right coronary arteries.

CONCLUSIONS

DS led to the implantation of a larger and shorter stent; this is probably because DS allows for more accurate assessment of the residual lesion after relief of spasm and thrombus, and may have clinical consequences in terms of stent thrombosis and restenosis.

Comparison of Immediate With Delayed Stenting Using the Minimalist Immediate Mechanical Intervention Approach in Acute ST-Segment-Elevation Myocardial Infarction: The MIMI Study

BACKGROUND

Delayed stent implantation after restoration of normal epicardial flow by a minimalist immediate mechanical intervention aims to decrease the rate of distal embolization and impaired myocardial reperfusion after percutaneous coronary intervention. We sought to confirm whether a delayed stenting (DS) approach (24-48 hours) improves myocardial reperfusion, versus immediate stenting, in patients with acute ST-segment-elevation myocardial infarction undergoing primary percutaneous coronary intervention.

METHODS AND RESULTS

In the prospective, randomized, open-label minimalist immediate mechanical intervention (MIMI) trial, patients (n=140) with ST-segment-elevation myocardial infarction ≤12 hours were randomized to immediate stenting (n=73) or DS (n=67) after Thrombolysis In Myocardial Infarction 3 flow restoration by thrombus aspiration. Patients in the DS group underwent a second coronary arteriography for stent implantation a median of 36 hours (interquartile range 29-46) after randomization. The primary end point was microvascular obstruction (% left ventricular mass) on cardiac magnetic resonance imaging performed 5 days (interquartile range 4-6) after the first procedure. There was a nonsignificant trend toward lower microvascular obstruction in the immediate stenting group compared with DS group (1.88% versus 3.96%; P=0.051), which became significant after adjustment for the area at risk (P=0.049). Median infarct weight, left ventricular ejection fraction, and infarct size did not differ between groups. No difference in 6-month outcomes was apparent for the rate of major cardiovascular and cerebral events.

CONCLUSIONS

The present findings do not support a strategy of DS versus immediate stenting in patients with ST-segment-elevation infarction undergoing primary percutaneous coronary intervention and even suggested a deleterious effect of DS on microvascular obstruction size.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01360242.

Invasive management without stents in selected acute coronary syndrome patients with a large thrombus burden: a prospective study of optical coherence tomography guided treatment decisions

AIMS

To assess whether a strategy of invasive management without stents in selected acute coronary syndrome (ACS) patients with a large thrombus burden (LTB) might be feasible and safe.

METHODS AND RESULTS

We performed a prospective non-randomised observational cohort study of invasive treatment decisions guided by optical coherence tomography (OCT) in selected ACS patients with LTB. Among 852 ACS patients who had undergone invasive coronary angiography, 101 (11.8%) patients with large thrombus burden on initial angiography underwent thrombectomy to restore TIMI 3 flow without stenting. All of these patients then had repeat angiography with OCT (days 0-2 [Group 1], days 3-6 [Group 2] or days 7-30 [Group 3]). No adverse events occurred between the initial and second angiograms. Residual thrombus was detected in 68% of patients with OCT (respectively, 94%, 79% and 32% in Group 1, Group 2 and Group 3), and 20% of cases with angiography. Plaque rupture was detected by OCT in 65% of cases. Minimal lumen area was 2.81 mm2, 3.40 mm2 and 4.89 mm2 in Group 1, Group 2 and Group 3, respectively. Sixty-two percent of patients were stented (respectively, 76%, 61% and 50%). During a minimum follow-up period of 12 months in all patients, one non-fatal MI occurred and one PCI was performed for angina.

CONCLUSIONS

Medical management without stents is safe and feasible in selected ACS patients with LTB. OCT revealed culprit lesion characteristics that were not disclosed by angiography and facilitated treatment decisions.

Deferred versus conventional stent implantation in patients with ST-segment elevation myocardial infarction (DANAMI 3-DEFER): an open-label, randomised controlled trial

BACKGROUND

Despite successful treatment of the culprit artery lesion by primary percutaneous coronary intervention (PCI) with stent implantation, thrombotic embolisation occurs in some cases, which impairs the prognosis of patients with ST-segment elevation myocardial infarction (STEMI). We aimed to assess the clinical outcomes of deferred stent implantation versus standard PCI in patients with STEMI.

METHODS

We did this open-label, randomised controlled trial at four primary PCI centres in Denmark. Eligible patients (aged >18 years) had acute onset symptoms lasting 12 h or less, and ST-segment elevation of 0·1 mV or more in at least two or more contiguous electrocardiographic leads or newly developed left bundle branch block. Patients were randomly assigned (1:1), via an electronic web-based system with permuted block sizes of two to six, to receive either standard primary PCI with immediate stent implantation or deferred stent implantation 48 h after the index procedure if a stabilised flow could be obtained in the infarct-related artery. The primary endpoint was a composite of all-cause mortality, hospital admission for heart failure, recurrent infarction, and any unplanned revascularisation of the target vessel within 2 years' follow-up. Patients, investigators, and treating clinicians were not masked to treatment allocation. We did analysis by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT01435408.

FINDINGS

Between March 1, 2011, and Feb 28, 2014, we randomly assigned 1215 patients to receive either standard PCI (n=612) or deferred stent implantation (n=603). Median follow-up time was 42 months (IQR 33-49). Events comprising the primary endpoint occurred in 109 (18%) patients who had standard PCI and in 105 (17%) patients who had deferred stent implantation (hazard ratio 0·99, 95% CI 0·76-1·29; p=0·92). Procedure-related myocardial infarction, bleeding requiring transfusion or surgery, contrast-induced nephopathy, or stroke occurred in 28 (5%) patients in the conventional PCI group versus 27 (4%) patients in the deferred stent implantation group, with no significant differences between groups.

INTERPRETATION

In patients with STEMI, routine deferred stent implantation did not reduce the occurrence of death, heart failure, myocardial infarction, or repeat revascularisation compared with conventional PCI. Results from ongoing randomised trials might shed further light on the concept of deferred stenting in this patient population.

FUNDING

Danish Agency for Science, Technology and Innovation, and Danish Council for Strategic Research.

Which Intraprocedural Thrombotic Events Impact Clinical Outcomes After Percutaneous Coronary Intervention in Acute Coronary Syndromes?: A Pooled Analysis of the HORIZONS-AMI and ACUITY Trials

OBJECTIVES

This study sought to determine the extent to which individual components of intraprocedural thrombotic events (IPTEs) are associated with adverse events.

BACKGROUND

IPTEs occurring during percutaneous coronary intervention (PCI) are associated with adverse in-hospital and late outcomes in patients with acute coronary syndromes.

METHODS

A total of 6,591 patients who underwent PCI for non-ST-segment elevation acute coronary syndromes/ST-segment elevation myocardial infarction in the ACUITY (Acute Catheterization and Urgent Intervention Triage StrategY) and HORIZONS-AMI (Harmonizing Outcomes with RevascularIZatiON and Stents in Acute Myocardial Infarction) trials underwent detailed frame-by-frame core laboratory angiographic analysis to assess for IPTEs. The associations of IPTE components with death, major bleeding, and major adverse cardiac events at 30 days were assessed using univariable analyses and multivariable models.

RESULTS

The overall incidence of IPTEs was 7.7%, with a greater incidence in ST-segment elevation myocardial infarction patients (12.2%) compared with non-ST-segment elevation acute coronary syndromes patients (3.5%). Specific components of IPTEs included no-reflow/slow reflow in 58.0%, new/worsened thrombus in 35.3%, distal embolization in 34.9%, abrupt closure in 19.8%, and intraprocedural stent thrombosis (IPST) in 9.5% of patients. Each IPTE component was independently associated with 30-day death, major bleeding, and MACE in multivariable models, with the strongest association observed for IPST (MACE hazard ratio: 7.51 [95% confidence interval: 4.36 to 12.94]).

CONCLUSIONS

The occurrence of IPTEs is not infrequent among high-risk acute coronary syndromes patients undergoing PCI, and each IPTE component was associated with subsequent adverse events. Although IPST represented <10% of IPTE events overall, it was the component with the strongest association with adverse events.

Deferred vs immediate stenting in ST elevation myocardial infarction: Potential interest in selected patients

BACKGROUND

Slow flow, no reflow and distal embolization often occur during primary angioplasty in ST segment elevation myocardial infarction (STEMI), compromising optimal myocardial reperfusion.

AIMS

This study aimed at assessing the impact of deferred stenting (DS) on periprocedural events as compared to immediate stenting (IS). The second objective was to gather the reasons advocated by the physicians for deferring stenting.

METHODS

All consecutive patients referred for primary angioplasty were included between September 2010 and November 2011. Physicians were free to choose the strategy between DS and IS but had to justify their choice. DS patients underwent a coronary angiogram control in a delay > 24h.

RESULTS

Ninety-eight patients were included. Forty patients underwent DS and 58 IS. DS strategy involved thrombus management by thromboaspiration (33 patients 82.5%) and by the use of AntiGpIIbIIIa (23 patients 62.2%). This strategy could be achieved with a low complication rate. In particular, one patient had a reocclusion leading to a rapid reintervention and one had a distal embolization. In comparison, 11 periprocedural events occurred in the IS subgroup. In addition, among DS patients, 7 were treated medically because of a non-significant stenosis. The major criteria considered by the operator to prefer DS in the presence of a TIMI 3 flow concerned thrombotic load.

CONCLUSION

This mono-centric experience confirmed the feasibility and the safety of DS. On top of reducing periprocedural events, it may allow for other treatment options in selected STEMI patients, e.g. surgery or medical treatment. The reasons leading physicians to choose DS were large thrombus burden on top of resolution of chest pain and normalization of the ECG. These criteria could help selecting situations in which DS may be of particular value as compared to IS.

Delayed Stenting for ST-Elevation Acute Myocardial Infarction in Daily Practice: A Single-Centre Experience

BACKGROUND

The minimalist immediate mechanical intervention (MIMI) strategy aims to restore normal anterograde flow in the culprit artery (by using manual thrombectomy or small-sized balloon predilation) and to defer potential stent implantation. This study evaluated the applicability and midterm clinical results of the MIMI strategy for ST-elevation myocardial infarction (STEMI) management.

METHODS

This observational study included consecutive patients admitted for ongoing STEMI (<24 hours' evolution) at 1 institution between June 2010 and June 2013. Revascularization was performed at the physician's discretion. We compared retrospectively "intentional immediate stenting" (standard technique) and "intentional delayed stenting" (MIMI technique).

RESULTS

Twenty percent of the 279 included patients were treated with the MIMI strategy. These patients were significantly younger and were more frequently men and smokers compared with patients who underwent the standard procedure. The rate of acute reocclusion of the culprit artery related to STEMI in the MIMI group was 1.8%. Drug-eluting stents were used more frequently in the MIMI group (52% vs 27% in the standard group; P < 0.001). The culprit lesion was stented less frequently in the patients treated with MIMI compared with patients in the other group (28.5% vs 9%; P < 0.001). The 1-year actuarial survival free from major adverse cardiovascular events was higher in the MIMI group than in the standard group (96.3% ± 1.8% vs 83.8% ± 2.5%; P = 0.01).

CONCLUSIONS

The MIMI strategy can be applied in selected patients with STEMI. In our centre, this strategy is associated with less systematic culprit lesion stenting and more implantation of drug-eluting stents. However, this needs to be evaluated further in a randomized trial.

[ST segment elevation myocardial infarction in a young patient: special physiopathology and unusual management]

We report the case of a 24-year-old patient admitted for anterior ST segment elevation myocardial complicated by ventricular fibrillation and revealing thrombotic sub occlusion of the left anterior descending coronary artery. Revascularization is achieved by manual thrombectomy and use of Glycoprotein GPIIbIIIa inhibitors and permits to restore TIMI 3 flow. Given the large thrombotic burden, the patient is initially treated medically (optimal anti thrombotic therapy without stenting) and benefits from angiographic control 48 hours later with imaging by Optical Coherence Tomography (OCT). It shows a reduction of thrombus burden and lack of significant underlying organic lesion (no organic stenosis or plaque rupture). In view of these data, it was decided to continue medical treatment alone without stenting. OCT imaging at 6 months shows atheroma without stenosis, thrombus or plaque rupture. This young patient remains asymptomatic and recovered normal left ventricular function with a 2-year follow-up.

Verapamil reverses myocardial no-reflow after primary percutaneous coronary intervention in patients with acute myocardial infarction

The present study evaluated the efficacy of intracoronary administration of verapamil to attenuate the no-reflow phenomenon following the primary percutaneous coronary intervention (PCI) in patients with the ST-segment elevation acute myocardial infarction (STEMI). A total of 201 patients with STEMI who underwent primary PCI within 12 h from the beginning of the heart attack were included. The no-reflow phenomenon was defined as substantial coronary anterograde flow of TIMI ≤2. Verapamil (100-200 μg) was injected into coronary artery immediately after no-reflow; the coronary arteriography was repeated later. Hundred and ninety-eight patients with STEMI successfully underwent primary PCI, and 246 stents were implanted with the average of 1.2 stents per patient. No-reflow occurred in 25 out of 198 patients (12.6%). Twenty-one (84%) patients developed the flow of TIMI ≥3 after intracoronary administration of verapamil, as revealed by repeated coronary angiography. Two patients developed transient hypotension which normalized without treatment within 3-5 min. Three patients showed sinus bradycardia, in one patient there was transient II sinoatrial block, and one patient developed type 1 atrioventricular block. All adverse effects were alleviated after intravenous injection of atropine (0.5-1 mg). In conclusion, the no-reflow phenomenon following primary PCI in patients with STEMI is significantly improved by intracoronary administration of verapamil which is useful to reduce cardiovascular events during operation.

A randomized trial of deferred stenting versus immediate stenting to prevent no- or slow-reflow in acute ST-segment elevation myocardial infarction (DEFER-STEMI)

OBJECTIVES

The aim of this study was to assess whether deferred stenting might reduce no-reflow and salvage myocardium in primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI).

BACKGROUND

No-reflow is associated with adverse outcomes in STEMI.

METHODS

This was a prospective, single-center, randomized, controlled, proof-of-concept trial in reperfused STEMI patients with ≥1 risk factors for no-reflow. Randomization was to deferred stenting with an intention-to-stent 4 to 16 h later or conventional treatment with immediate stenting. The primary outcome was the incidence of no-/slow-reflow (Thrombolysis In Myocardial Infarction ≤2). Cardiac magnetic resonance imaging was performed 2 days and 6 months after myocardial infarction. Myocardial salvage was the final infarct size indexed to the initial area at risk.

RESULTS

Of 411 STEMI patients (March 11, 2012 to November 21, 2012), 101 patients (mean age, 60 years; 69% male) were randomized (52 to the deferred stenting group, 49 to the immediate stenting). The median (interquartile range [IQR]) time to the second procedure in the deferred stenting group was 9 h (IQR: 6 to 12 h). Fewer patients in the deferred stenting group had no-/slow-reflow (14 [29%] vs. 3 [6%]; p = 0.006), no reflow (7 [14%] vs. 1 [2%]; p = 0.052) and intraprocedural thrombotic events (16 [33%] vs. 5 [10%]; p = 0.010). Thrombolysis In Myocardial Infarction coronary flow grades at the end of PCI were higher in the deferred stenting group (p = 0.018). Recurrent STEMI occurred in 2 patients in the deferred stenting group before the second procedure. Myocardial salvage index at 6 months was greater in the deferred stenting group (68 [IQR: 54% to 82%] vs. 56 [IQR: 31% to 72%]; p = 0.031].

CONCLUSIONS

In high-risk STEMI patients, deferred stenting in primary PCI reduced no-reflow and increased myocardial salvage. (Deferred Stent Trial in STEMI; NCT01717573).

Safety of lone thrombus aspiration without concomitant coronary stenting in selected patients with acute myocardial infarction

AIMS

Although the benefit of concomitant thrombus aspiration (TA) in primary percutaneous coronary intervention (PPCI) treatment of acute ST-segment elevation myocardial infarction (STEMI) has been demonstrated, very little information is available on its safety as a lone revascularisation technique in this setting. We present our experience in a cohort of patients with STEMI treated only with TA, without concomitant interventional devices.

METHODS AND RESULTS

In 28 patients with STEMI, PPCI was performed using only TA on the grounds of an excellent angiographic result and in order to avoid the potential risks associated with balloon dilatation or stenting. The patients were younger than in the overall PPCI population (n=1,737) at our institution (52±18 vs. 63±14 years, p<0.001), with a history of atrial fibrillation in six (21%), cocaine abuse in three (11%) and mechanical cardiac valves in two (7%). Twenty-eight patients (89%) presented STEMI with Killip class I, two (7%) with cardiogenic shock, and two (7%) with sudden cardiac death. A significant reduction in TIMI thrombus grade (5 [4-5] to 1 [0-1.75], p<0.001) and coronary stenosis percentage (%) (87.2±21.3 to 11.3±0.9, p<0.001) as well as an increase in final TIMI flow (0 [0-2] to 3 [3-3], p<0.001) and minimum luminal diameter (mm) (0.89±1.01 to 2.42±0.70, p<0.001) were noted after TA. Transient no-reflow phenomenon, residual intracoronary thrombus and minor distal thrombus embolisation were observed in two (7.1%), 11 (39.3%) and 10 (25.7%) patients, respectively. All but one patient remained asymptomatic during hospital admission. Scheduled control angiography was performed 6±2 days (min-max, 3-10 days) after PPCI in 11 (39%) patients, demonstrating coronary artery patency and TIMI flow grade 3 in all patients. During clinical follow-up, successfully performed in all patients at 40±23 months (min-max, six to 95 months), there was one sudden cardiac death (4%) and three (11%) non-cardiac deaths. One patient (4%) was admitted with non-STEMI (new coronary angiogram without stenosis) and the remaining 22 (78.5%) remained asymptomatic and free of cardiac events.

CONCLUSIONS

Our series suggests that lone TA might be safely performed as a primary revascularisation procedure in STEMI in selected cases. Further information based on additional and larger studies is recommended to confirm our findings.

Immediate vs. delayed stenting in acute myocardial infarction: a systematic review and meta-analysis

AIMS

To conduct a meta-analysis of studies comparing immediate versus delayed stenting in populations where primary percutaneous coronary intervention (PCI) or early invasive revascularisation was the initial mode of reperfusion.

METHODS AND RESULTS

We identified five non-randomised studies and one randomised trial for a total of 590 patients in studies comparing immediate to delayed stenting in populations where primary PCI or early invasive revascularisation was the initial mode of reperfusion. In non-randomised studies, delayed stenting was associated with a reduction of procedure-related angiographic events (OR=0.13, 95% credible interval [CrI]: 0.03- 0.36). No differences were observed in the rates of major bleeding (OR=0.81, 95% CrI: 0.01-13.42) and major adverse cardiac events (OR=0.40, 95% CrI: 0.09-1.91), between delayed and immediate stenting. In one randomised trial, delayed stenting was associated with a reduction in myocardial infarction during hospitalisation (39% vs. 60%; relative risk [RR]=0.55, 95% confidence interval [CI]: 0.39-0.80). None of the patients assigned to delayed stenting experienced a major adverse cardiac event in the interval between the initial angiogram and the stenting.

CONCLUSIONS

Delayed stent implantation is associated with better angiographic outcomes. Randomised trials are required to assess whether delayed stenting translates into better long-term cardiac outcomes.

Coronary vessel diameters during and after primary percutaneous coronary artery intervention

BACKGROUND

Primary percutaneous coronary intervention (P-PCI) is the gold standard treatment for acute coronary syndromes. Plasma levels of catecholamines and other vasopressors are elevated during acute myocardial infarction (AMI) and coronary vasoconstriction is frequent. We aimed to compare the reference vessel diameter (RVD) of the infarct-related artery (IRA) during primary PCI and after an average of 3 days.

METHODS

Coronary angiography (CAG) was performed on 58 patients with acute ST-segment elevation myocardial infarction (STEMI) and TIMI 3 flow after P-PCI (43 men, 15 women; mean age, 55.5 ± 10 years). TIMI 3 flow was achieved either by simple balloon dilatation and/or thrombus aspiration. Lesion length, RVD, minimal lumen diameter (MLD), mean vessel diameter (meanD), and area of stenosis were compared during P-PCI and follow-up CAG.

RESULTS

RVD, MLD, and meanD values were significantly higher during the follow-up CAG than after P-PCI (RVD 2.7 ± 0.7 mm vs. 2.9 ± 0.7 mm, p = 0.001; MLD 1.5 ± 0.5 mm vs. 1.7 ± 0.4 mm, p = 0.002; meanD 2.2 ± 0.5 mm vs. 2.4 ± 0.5 mm, p = 0.001). Area of stenosis values were significantly lower during the follow-up CAG than after primary PCI (69.5 ± 16.5 % vs. 62.1 ± 15 %, p = 0.001). Lesion lengths were not statistically significant during the follow-up CAG and primary PCI (lesion length 24.0 ± 10.8 mm vs. 22.1 ± 8.8 mm, p > 0.05).

CONCLUSION

This study showed that RVD was higher at the follow-up CAG a few days after AMI in patients who had TIMI 3 flow after P-PCI with simple balloon dilatation and/or thrombus aspiration. A delay of a few days for stent implantation in P-PCI allows for larger-diameter stent use and may help to reduce stent thrombosis and restenosis rates.

[Management of acute myocardial infarction. How improve primary angioplasty?]

Besides the reduction of the delay for the myocardium reperfusion, the revascularization must be optimized by tools and techniques of percutaneous intervention. These are pharmacological, mechanical and procedural. The appeal to antiGP2b3a can be useful in the cathlab. Its intracoronary administration seems to improve drug efficiency. Among the protection devices against the coronary clot embolism, only thrombectomy by manual aspiration gives an evidence of its efficiency. During the primary angioplasty, the drug eluting stent could to be implanted only for the patients and the lesions with high risk of TLR. In some cases, still difficult to identify, a more controlled revascularization would allow to minimize the reperfusion injury. The radial access, decreasing the rate of haemorrhagic complications, must be preferred in first intention.

[Postconditioning in acute myocardial infarction: Primary angioplasty revisited?]

Early reperfusion of ischemic myocardium is the mean to improve prognosis of acute myocardial infarction. Nevertheless, reperfusion injury due to immediate acidosis correction and subsequent Ca(2+) overload results in formation of the mitochondrial permeability transition pore. The consequence is the death of viable myocardium due to onconecrosis and apoptosis. Mechanical (Stuttering reperfusion) or pharmacological postconditioning (cyclosporine A, adenosine…) is able to prevent reperfusion injury resulting in more myocardial salvage.

Partial vs full coverage for tandem lesions in culprit vessel during primary coronary intervention in patients with acute ST-elevation myocardial infarction--the PERFECT-AMI study

BACKGROUND

The efficacy of partial vs full coverage for tandem lesions in the culprit vessel during primary percutaneous coronary intervention (PCI) after ST-elevation myocardial infarction (STEMI) was compared in the present study.

METHODS AND RESULTS

The 76 patients with STEMI and tandem lesions in the culprit vessel were randomized to receive stent implantation for an occluded/culprit lesion only (partial group) or complete coverage of lesions (full group). After PCI, patients in the partial group had more complete ST-segment resolution (STR) at 90 min (60.5% vs 28.9%, P=0.006), Thrombosis In Myocardial Infarction (TIMI) flow grade 3 (68.4% vs 28.9%, P=0.001), and myocardial blush grade 3 (42.1% vs 15.8%, P=0.04) than those in the full group. At 6 months, the major adverse cardiac events-free survival rate did not differ significantly between groups, but left ventricular (LV) ejection fraction was improved in the partial group. Multivariate analysis revealed pre-procedural TIMI flow grade >1 and door-to-balloon time <90 min were positively associated with complete STR at 90 min, whereas full coverage for tandem lesions was an independent factor for poor STR (odds ratio 2.58, 95% confidence interval 1.08-5.42, P=0.03).

CONCLUSIONS

For acute STEMI patients with tandem lesions in the culprit vessel, primary stenting for the occluded lesion only is beneficial in improving myocardial perfusion and LV function.

Clinical and procedural predictors of no-reflow phenomenon after primary percutaneous coronary interventions: experience at a single center

BACKGROUND

The aim of the study was to identify clinical factors, angiographic findings, and procedural features that predict no-reflow phenomenon (Thrombolysis In Myocardial Infarction (TIMI) flow grade < or =2) in patients with acute myocardial infarction (AMI) who undergo primary percutaneous coronary intervention (PCI).

METHODS AND RESULTS

A series of 382 consecutive patients with AMI underwent primary PCI within 12 h of symptom onset. Patients with ischemic symptoms continuing for more than 12 h were also included. Clinical, angiographic and procedural data were collected for each subject. Ninety-three (24.3%) of the patients developed no-reflow phenomenon, and their findings were compared with those of the reflow group. Univariate analysis showed that advanced age (>60 years), delayed reperfusion (> or =4 h), low (< or =1) TIMI flow prior to PCI, cut-off type total occlusion, high thrombus burden on baseline angiography, long target lesion (>13.5 mm) and large vessel diameter all correlated with no-reflow (p<0.05 for all). Multiple logistic regression analysis identified that advanced age (odds ratio (OR) 1.04, p=0.001), delayed reperfusion (OR 1.4, p=0.0004), low TIMI flow before primary PCI (OR 1.1, p=0.0002), target lesion length (OR 5.1, p=0.0003) and high thrombus burden (OR 1.6, p=0.03) on angiography as independent predictors of no-reflow phenomenon.

CONCLUSION

The occurrence of no-reflow phenomenon after primary PCI can be predicted using simple clinical, angiographic and procedural features. In this selected group of patients, adjunctive pharmacotherapy and/or distal protection device may be of value.

Predictors and clinical significance of angiographically detected distal embolization after primary percutaneous coronary interventions

OBJECTIVES

The aim of this study was to investigate clinical, angiographic and procedural predictors of distal embolization (DE) on angiography after primary percutaneous coronary intervention (PCI). The impact of DE on outcome in the first 30 days was also assessed.

METHODS

Between January 2004 and April 2006, primary PCI was performed in 212 consecutive patients with acute myocardial infarction (AMI) of < or = 12-h duration.

RESULTS

Distal embolization was present in 27 patients (12.7%) and more often observed in female sex (27.5 vs. 10.4%, P=0.01), in patients with right coronary artery involvement (52 vs. 28%, P=0.02), prerevascularization thrombolysis in myocardial infarction flow < or = 1 (89 vs. 69%, P=0.03), in the presence of high thrombus burden (92.6 vs. 39.5%, P=0.0009), and a long target lesion in the infarct-related artery (>14.5 mm, 74 vs. 29%, P<0.0001). By multiple stepwise logistic regression analysis, only the presence of high thrombus burden before the PCI procedure [odds ratio (OR)=5.2, 95% confidence interval (CI)=1.09-24.97, P=0.03)] and target lesion length (>14.5 mm, OR=3.9, 95% CI=1.45-10.60, P=0.007) were found independent predictors of DE. Patients with DE had an increased risk of target vessel revascularization (26 vs. 5%, P=0.001) and short-term mortality (29.6 vs. 7.5%, P=0.002) when compared with patients without angiographic signs of embolization.

CONCLUSIONS

In patients who undergo primary PCI, high thrombus burden on angiography before PCI and/or a long target lesion in the infarct-related artery increase the risk of DE and subsequent short-term mortality.