Impact of direct stenting on myocardial injury assessed by cardiac magnetic resonance imaging and prognosis in ST-elevation myocardial infarction

Coronary microvascular obstruction and dysfunction in patients with acute myocardial infarction

Despite prompt epicardial recanalization in patients presenting with ST-segment elevation myocardial infarction (STEMI), coronary microvascular obstruction and dysfunction (CMVO) is still fairly common and is associated with poor prognosis. Various pharmacological and mechanical strategies to treat CMVO have been proposed, but the positive results reported in preclinical and small proof-of-concept studies have not translated into benefits in large clinical trials conducted in the modern treatment setting of patients with STEMI. Therefore, the optimal management of these patients remains a topic of debate. In this Review, we appraise the pathophysiological mechanisms of CMVO, explore the evidence and provide future perspectives on strategies to be implemented to reduce the incidence of CMVO and improve prognosis in patients with STEMI.

The impact of primary percutaneous coronary intervention strategies during ST-elevation myocardial infarction on the prevalence of coronary microvascular dysfunction

Coronary microvascular dysfunction (CMD) is a common complication of ST-segment elevation myocardial infarction (STEMI) and can lead to adverse cardiovascular events. This is a non-randomized, observational, prospective study of STEMI patients with multivessel disease who underwent primary PCI, grouped based on whether they underwent balloon pre-dilatation stenting or direct stenting of the culprit lesion. Coronary physiology measurements were performed 3 months post-PCI including coronary flow reserve (CFR) and index of microcirculatory resistance (IMR) measurements at the culprit vessel. The primary endpoint was the prevalence of CMD at 3 months, defined as IMR ≥ 25 or CFR < 2.0 with a normal fractional flow reserve. Secondary endpoints included major adverse cardiovascular events (MACE) at 12 months. Two hundred ten patients were enrolled; most were men, 125 (59.5%), with a median age of 65 years. One hundred twelve (53.2%) underwent balloon pre-dilatation before stenting, and 98 (46.7%) underwent direct stenting. The prevalence of CMD at 3 months was lower in the direct stenting group than in the balloon pre-dilatation stenting group (12.24% vs. 40.18%; p < 0.001). Aspiration thrombectomy and administration of intracoronary glycoprotein IIb/IIIa inhibitors were associated with lower odds of CMD (OR = 0.175, p = 0.001 and OR = 0.113, p = 0.001, respectively). Notably, MACE in patients who underwent direct stenting was lower than in those who underwent balloon pre-dilatation before stenting (14.29% vs. 26.79%; p = 0.040). In STEMI patients with multivessel disease, direct stenting of the culprit lesion, aspiration thrombectomy and administration of intracoronary glycoprotein IIb/IIIa inhibitors were associated with a lower prevalence of CMD at 3 months and lower incidence of MACE at 12 months compared with balloon pre-dilatation stenting.This trial is registered at https://ichgcp.net/clinical-trials-registry/NCT05406297 .

Direct Stenting versus Conventional Stenting in Patients with ST-Segment Elevation Myocardial Infarction-A COMPARE CRUSH Sub-Study

BACKGROUND

Direct stenting (DS) compared with conventional stenting (CS) after balloon predilatation may reduce distal embolization during percutaneous coronary intervention (PCI), thereby improving tissue reperfusion. In contrast, DS may increase the risk of stent underexpansion and target lesion failure.

METHODS

In this sub-study of the randomized COMPARE CRUSH trial (NCT03296540), we reviewed the efficacy of DS versus CS in a cohort of contemporary, pretreated ST-segment elevation myocardial infarction (STEMI) patients undergoing primary PCI. We compared DS versus CS, assessing (1) stent diameter in the culprit lesion, (2) thrombolysis in myocardial infarction (TIMI) flow in the infarct-related artery post-PCI and complete ST-segment resolution (STR) one-hour post-PCI, and (3) target lesion failure at one year. For proportional variables, propensity score weighting was applied to account for potential treatment selection bias.

RESULTS

This prespecified sub-study included 446 patients, of whom 189 (42%) were treated with DS. Stent diameters were comparable between groups (3.2 ± 0.5 vs. 3.2 ± 0.5 mm, p = 0.17). Post-PCI TIMI 3 flow and complete STR post-PCI rates were similar between groups (DS 93% vs. CS 90%, adjusted OR 1.16 [95% CI, 0.56-2.39], p = 0.69, and DS 72% vs. CS 58%, adjusted OR 1.29 [95% CI 0.77-2.16], p = 0.34, respectively). Moreover, target lesion failure rates at one year were comparable (DS 2% vs. 1%, adjusted OR 2.93 [95% CI 0.52-16.49], p = 0.22).

CONCLUSION

In this contemporary pretreated STEMI cohort, we found no difference in early myocardial reperfusion outcomes between DS and CS. Moreover, DS seemed comparable to CS in terms of stent diameter and one-year vessel patency.

Effect of direct stenting on microvascular dysfunction during percutaneous coronary intervention in acute myocardial infarction: a randomized pilot study

Objective

Whether direct stenting (DS) without predilatation during primary percutaneous coronary intervention (PPCI) reduces microvascular dysfunction in patients with ST-elevation myocardial infarction is unclear. We performed a randomized study to assess the effect of DS on microvascular reperfusion.

Methods

Seventy-two patients undergoing PPCI were randomly assigned to the DS or conventional stenting (CS) with predilatation groups. The primary endpoint was the post-PPCI index of microcirculatory resistance (IMR). We compared thrombolysis in myocardial infarction myocardial perfusion (TMP) grades, ST-segment resolution, and long-term clinical outcomes between the groups.

Results

Microvascular reperfusion parameters immediately after PPCI (e.g., the IMR, TMP grade, and ST-segment resolution) were not different between the groups. However, significantly fewer patients in the DS group had the IMR measured because of no-reflow or cardiogenic shock during PPCI than those in the CS group. No differences were found in left ventricular functional recovery or clinical outcomes between the groups.

Conclusions

This trial showed no effect of DS on the IMR. However, our finding should be interpreted with caution because the number of patients who could not have the IMR measured was higher in the CS group than in the DS group. A larger randomized trial is required (Research Registry number: 8079).

Effect of Coronary Thrombus Aspiration in Non ST Elevation Acute Coronary Syndrome Patients on Three-Year Survival- Does it add any Benefit?

We assessed the effect of thrombus aspiration (TA) during percutaneous coronary intervention (PCI) on in-hospital and 3-year mortality in consecutive non-ST segment elevation myocardial infarction (n = 189) and unstable angina pectoris (n = 148) patients (n = 337) between 2011 and 2016. In total, 153 patients (45.4%) underwent TA. The number of patients with postoperative thrombolysis in terms of myocardial infarction grade 3 blood flow (P < .001) and myocardial blush grade 3 (P < .001) were significantly higher in all TA groups. At 6-, 12- and 24-month post-PCI, the mean left ventricular ejection fraction was significantly higher in the all TA groups versus the stand alone PCI group (P < .001). Thrombus aspiration was associated with a significant improvement both in epicardial flow, myocardial perfusion and left ventricular ejection fraction. Thrombus aspiration during PCI in all acute coronary syndrome (except ST segment elevation) patients was associated with better survival compared with stand alone PCI group at 3-year follow-up (P = .019).

A fresh look at coronary microembolization

Mechanical stress from haemodynamic perturbations or interventional manipulation of epicardial coronary atherosclerotic plaques with inflammatory destabilization can release particulate debris, thrombotic material and soluble substances into the coronary circulation. The physical material obstructs the coronary microcirculation, whereas the soluble substances induce endothelial dysfunction and facilitate vasoconstriction. Coronary microvascular obstruction and dysfunction result in patchy microinfarcts accompanied by an inflammatory reaction, both of which contribute to progressive myocardial contractile dysfunction. In clinical studies, the benefit of protection devices to retrieve atherothrombotic debris during percutaneous coronary interventions has been modest, and the treatment of microembolization has mostly relied on antiplatelet and vasodilator agents. The past 25 years have witnessed a relative proportional increase in non-ST-segment elevation myocardial infarction in the presentation of acute coronary syndromes. An associated increase in the incidence of plaque erosion rather than rupture has also been recognized as a key mechanism in the past decade. We propose that coronary microembolization is a decisive link between plaque erosion at the culprit lesion and the manifestation of non-ST-segment elevation myocardial infarction. In this Review, we characterize the features and mechanisms of coronary microembolization and discuss the clinical trials of drugs and devices for prevention and treatment.

Comparison of direct stenting with conventional strategy on myocardial impairments in ST-segment elevation myocardial infarction: a cardiac magnetic resonance imaging study

Direct stenting (DS) without pre-dilatation of the culprit lesion might improve myocardial perfusion and prognosis in patients undergoing percutaneous coronary intervention for ST-elevation myocardial infarction (STEMI); however, some studies report conflicting results. We investigated whether DS provides incremental myocardial benefits over conventional stenting (CS) in STEMI patients based on cardiac magnetic resonance imaging (CMR) measures. Reperfused patients who underwent CMR examinations within 1 week of STEMI onset were selected from a multicenter CMR registry of STEMI (NCT: 03768453). Patients were stratified into either a DS or CS group. Each group comprised 137 patients after 1:1 propensity score matching. Major adverse events (MACEs), including death, myocardial re-infarction, re-admission for heart failure, and stroke were noted during a median period of 44 months (interquartile range 32-58 months). DS was associated with larger (p = 0.007) and shorter (p = 0.005) stent sizes than CS. DS and CS achieved comparable angiographic TIMI-3 flow grades (p = 0.86) and myocardial blush grades (p = 0.70). There were no group differences regarding the incidence of CMR manifestations of microvascular dysfunction, including microvascular obstruction (MVO) (p = 0.89) and intramyocardial hemorrhage (p = 0.47), the extent of MVO (p = 0.21), infarction size (p = 0.83), or left ventricular ejection fraction (p = 0.57). Kaplan-Meier analysis revealed similar risks of MACEs (log rank p = 0.909), which occurred in 23.4% of DS and 26.3% of CS patients (p = 0.576). DS did not show any incremental benefits over CS on myocardial impairments as evaluated using CMR.Clinical Trial Registration: Clinicaltrials.gov, NCT: 03768453.

Long-term outcome after thrombus aspiration in non-ST-elevation myocardial infarction: results from the TATORT-NSTEMI trial : Thrombus aspiration in acute myocardial infarction

AIMS

To investigate the long-term prognostic value of aspiration thrombectomy in conjunction with primary percutaneous coronary intervention (PCI) compared to conventional PCI in patients with non-ST-elevation myocardial infarction (NSTEMI).

METHODS

In the randomized TATORT-NSTEMI (Thrombus aspiration in thrombus containing culprit lesions in non-ST-elevation myocardial infarction) trial, NSTEMI patients with thrombus containing culprit lesions were randomized to either PCI with aspiration thrombectomy or conventional PCI. The endpoint was a combination of all-cause death, reinfarction and new congestive heart failure.

RESULTS

From 440 patients initially randomized, outcome data were available in 432 (98.2%) patients at a median follow-up of 4.9 (interquartile range [IQR] 4.4-5.0) years. Thrombectomy was associated with a significant reduction of the combined endpoint compared to conventional PCI (19.9% vs. 30.7%, p = 0.01). This finding was primarily driven by a reduced rate of reinfarction with thrombectomy (3.4% vs. 10.3%, p = 0.01). Thrombectomy was still independently associated with the combined endpoint after multivariable adjustment (hazard ratio [HR] 0.47, 95% confidence interval [CI] 0.30-0.76, p = 0.002). Findings were consistent across all analyzed subgroups (p values for interaction all > 0.05).

CONCLUSIONS

In NSTEMI, thrombus aspiration is associated with favorable clinical outcome during long-term follow-up.

CLINICAL TRIAL REGISTRATION

NCT01612312.

Importance of infarct size versus other variables for clinical outcomes after PPCI in STEMI patients

Despite promising experimental studies and encouraging proof-of-concept clinical trials, interventions aimed at limiting infarct size have failed to improve clinical outcomes in patients with ST-elevation myocardial infarction (STEMI). Our objective was to examine whether variables (cardiovascular risk factors, comorbidities, post-procedural variables, cotreatments) might be associated with clinical outcomes in STEMI patients independently from infarct size reduction. The present study was based on a post hoc analysis of the CIRCUS trial database (Clinicaltrials.gov NCT01502774) that assessed the clinical benefit of a single intravenous bolus of cyclosporine in 969 patients with anterior STEMI. Since cyclosporine had no detectable effect on clinical outcomes as well as on any measured variable, we here considered the whole study population as one group. Multivariate analysis was performed to address the respective weight of infarct size and variables in clinical outcomes. Multivariate analysis revealed that several variables (including gender, hypertension, renal dysfunction, TIMI flow grade post-PCI < 3, and treatment administered after PCI with betablockers and angiotensin-converting enzyme inhibitors) had per se a significant influence on the occurrence of [death or hospitalization for heart failure] at 1 year. The relative weight of infarct size and variables on the composite endpoint of [death or hospitalization for heart failure] at 1 year was 18% and 82%, respectively. Several variables contribute strongly to the clinical outcomes of STEMI patients suggesting that cardioprotective strategy might not only focus on infarct size reduction.

Syndecan-1 Predicts Outcome in Patients with ST-Segment Elevation Infarction Independent from Infarct-related Myocardial Injury

Syndecan-1 (sdc1) is a surface protein part of the endothelial glycocalyx (eGC). Soluble sdc1 is derived from shedding and indicates damaged eGC. We assessed the predictive value of plasma sdc1 concentrations for future cardiovascular events in acute reperfused ST-segment elevation myocardial infarction (STEMI) patients. A total of 206 patients admitted for STEMI were included in this study (29% female; age 65 ± 12 years) and followed-up for six months. Plasma samples were obtained post-intervention and analyzed for sdc1 by Enzyme-linked Immunosorbent Assay (ELISA). Primary outcome was six-month-mortality. Sdc1 did not correlate with biomarkers such as creatine kinase (CK) (r = 0.11; p = 0.01) or troponin (r = −0.12; p = 0.09), nor with infarct size (r = −0.04; p = 0.67) and myocardial salvage index (r = 0.11; p = 0.17). Sdc-1 was associated with mortality (changes per 100 ng/mL sdc-1 concentration; HR 1.08 95% 1.03–1.12; p = 0.001). An optimal cut-off was calculated at >120 ng/mL. After correction for known risk factors sdc1 >120 ng/mL was independently associated with mortality after 6 months. In our study, sdc1 is independently associated with six-month-mortality after STEMI. Combining clinical evaluation and different biomarkers assessing both infarct-related myocardial injury and systemic stress response might improve the accuracy of predicting clinical prognosis in STEMI patients.