Role of deferred stenting in patients with ST elevation myocardial infarction treated with primary percutaneous coronary intervention: A systematic review and meta-analysis

Efficacy and safety of drug-coated balloon for de novo lesions of large coronary arteries: Systematic review and meta-analysis of randomized controlled trials

Background

Drug-coated balloon (DCB) is a novel approach to avoiding stent-related complications and has proven effective for the treatment of in-stent restenosis (ISR) and small vessels. However, its role in the treatment of de novo lesions in large vessels is less settled.

Aims

To estimate the efficacy and safety of drug-coated balloon versus stent in the treatment of de novo lesions in large coronary arteries.

Methods

We searched the literature until April 2023. We judged the safety of DCB based on major adverse cardiovascular events (MACEs), cardiac death, all-cause mortality, non-fatal myocardial infarction, target lesion revascularization (TLR), and bleeding event; and efficacy according to late lumen loss (LLL), minimum lumen diameter (MLD). We conducted subgroup analyses according to stent type and whether urgent PCI was required.

Results

A total of 10 RCTs were included. Overall, LLL (mean difference (MD) = -0.19, 95 % confidence interval (CI): -0.32 to -0.06, P = 0.003) was lower in the DCB group than in the Stent arm. This effect was consistent in subgroup analysis regardless of stent type and disease type. In terms of safety indicators, there were no significant differences between DCB and stent. The subgroup analyses found that safety indicators showed no significant differences between DCB and drug-eluting stent (DES), but TLR was lower in the DCB than in the bare metal stent (BMS). Moreover, in ST-elevation myocardial infarction (STEMI), safety indicators and LLL showed no significant differences between DCB and DES, but MLD in the DCB was smaller. While in patients with excluded STEMI, MACE and TLR was lower in the DCB compared with the overall stent.

Conclusions

DCB could be a promising alternative for treating de novo lesions in large coronary arteries with satisfactory efficacy and low risk, superior to BMS and not inferior to DES, with a trend toward lower late lumen loss.

Microvascular Obstruction in Acute Myocardial Infarction, a Potential Therapeutic Target

Microvascular obstruction (MVO) is a recognised phenomenon following mechanical reperfusion in patients presenting with ST-segment elevation myocardial infarction (STEMI). Invasive and non-invasive modalities to detect and measure the extent of MVO vary in their accuracy, suggesting that this phenomenon may reflect a spectrum of pathophysiological changes at the level of coronary microcirculation. The importance of detecting MVO lies in the observation that its presence adds incremental risk to patients following STEMI treatment. This increased risk is associated with adverse cardiac remodelling seen on cardiac imaging, increased infarct size, and worse patient outcomes. This review provides an outline of the pathophysiology, clinical implications, and prognosis of MVO in STEMI. It describes historic and novel pharmacological and non-pharmacological therapies to address this phenomenon in conjunction with primary PCI.

Novel Applications for Invasive and Non-invasive Tools in the Era of Contemporary Percutaneous Coronary Revascularisation

Percutaneous coronary intervention (PCI) is an expanding treatment option for patients with coronary artery disease (CAD). It is considered the default strategy for the unstable presentation of CAD. PCI techniques have evolved over the last 4 decades with significant improvements in stent design, an increase in functional assessment of coronary lesions, and the use of intra-vascular imaging. Nonetheless, the morbidity and mortality related to CAD remain significant. Advances in technology have allowed a better understanding of the nature and progression of CAD. New tools are now available that reflect the pathophysiological changes at the level of the myocardium and coronary atherosclerotic plaque. Certain changes within the plaque would render it more prone to rupture leading to acute vascular events. These changes are potentially detected using novel tools invasively, such as near infra-red spectroscopy, or non-invasively using T2 mapping cardiovascular magnetic resonance imaging (CMR) and ¹⁸F-Sodium Fluoride positron emission tomography/ computed tomography. Similarly, changes at the level of the injured myocardium are feasibly assessed invasively using index microcirculatory resistance or non-invasively using T1 mapping CMR. Importantly, these changes could be detected immediately with the opportunity to tailor treatment to those considered at high risk. Concurrently, novel therapeutic options have demonstrated promising results in reducing future cardiovascular risks in patients with CAD. This Review article will discuss the role of these novel tools and their applicability in employing a mechanical and pharmacological treatment to mitigate cardiovascular risk in patients with CAD.

Approach to high intracoronary thrombus burden in the era of COVID-19

Since the start of the COVID-19 pandemic, several cases have reported extensive multivessel coronary thrombosis as a cardiovascular manifestation of SARS-CoV-2 infection. This case describes a patient who developed non-ST elevation myocardial infarction during hospitalization for acute hypoxic respiratory failure due to COVID-19. We review the immediate and delayed revascularisation strategies of culprit and non-culprit lesions in the setting of high intracoronary thrombus burden induced by SARS-CoV-2. Successful percutaneous intervention and stenting of a culprit lesion and resolution of an intracoronary thrombus using a delayed strategy of lesion passivation with adjuvant pharmacotherapy are demonstrated on index and follow-up angiography.

Should Deferred Stenting Still Be Considered in ST-Elevation Myocardial Infarction with High Thrombus Burden?

Patients with ST-elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI) may demonstrate distal microvascular embolization of thrombotic materials. We retrospectively examined 20 cases displaying extensive thrombus in the infarct-related artery (IRA), treated either with a two-step procedure, with interim tirofiban infusion, or immediate stent implantation. Distal embolization tended to be more common in the latter strategy, but, overall, the outcome was comparable. Thus, a two-staged procedure may be considered in selected cases of primary PCI associated with high thrombus burden.

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.

Clinical, Laboratory, and Procedural Predictors of No-Reflow in Patients Undergoing Primary Percutaneous Coronary Intervention

Background: No-reflow is a major challenging issue in the management of patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). This study aimed to investigate the clinical, laboratory, and procedural predictors of no-reflow.

Methods: This study was conducted on 378 patients with STEMI admitted to Dr. Heshmat Educational and Remedial Center (a referral heart hospital in Rasht, Iran) between 2015 and 2017. The study population was divided based on the thrombolysis in myocardial infarction (TIMI) flow grade and the myocardial blush grade into no-reflow and reflow groups. The clinical, laboratory, and procedural characteristics at admission were compared between the 2 groups using the multivariate logistic regression analysis.

Results: The mean age of the participants was 58.57±11.49 years, and men comprised 74.1% of the study population. The no-reflow phenomenon was found in 77 patients. The no-reflow group was significantly older and more likely to be female; additionally, it had higher frequencies of hypertension, diabetes mellitus, hyperlipidemia, and a history of cardiovascular diseases. The multivariate logistic regression analysis showed that age >60 years (OR=1.05, 95% CI:1.00–1.09), hypertension (OR=2.91, 95% CI:1.35–6.27), diabetes (OR=4.18, 95% CI:1.89–9.22), a low systolic blood pressure (OR=3.53, 95% CI:1.02–12.2), a history of cardiovascular diseases (OR=4.29, 95% CI:1.88–9.77), chronic heart failure (OR=4.96, 95% CI:1.23–20), a low initial TIMI flow grade (OR=7.58, 95% CI:1.46–39.2 ), anemia (OR=3.42, 95% CI:1.33–8.77), and stenting vs. balloon angioplasty (OR=0.42, 95% CI:0.19–0.91) were the significant independent predictors of no-reflow.

Conclusion: This study revealed some clinical, laboratory, and procedural predictors of no-reflow for the prediction of high-risk patients and their appropriate management to reduce the risk of no-reflow.

Correlation between intracoronary thrombus components and coronary blood flow after percutaneous coronary intervention for acute myocardial infarction at different onset time

BACKGROUND

Acute myocardial infarction (AMI) is a leading cause of mortality. Early reperfusion to restore blood flow is crucial to successful treatment. In the current reperfusion regimen, an increasing number of patients have benefited from direct percutaneous coronary intervention (PCI). In order to understand whether there is a correlation between the components of coronary thrombosis and the absence of reflow or slow blood flow after coronary stent implantation in direct PCI, we collected data on direct PCI cases in our hospital between January 2016 and November 2018.

AIM

To investigate the correlation between intracoronary thrombus components and coronary blood flow after stent implantation in direct PCI in AMI.

METHODS

We enrolled 154 patients (85 male and 69 female, aged 36–81 years) with direct PCI who underwent thrombus catheter aspiration within < 3, 3–6 or 6–12 h of onset of AMI between January 2016 and November 2018. The thrombus was removed for pathological examination under a microscope. The patients of the three groups according to the onset time of AMI were further divided into those with a white or red thrombus. The thrombolysis in myocardial infarction (TIMI) blood flow after stent implantation was recorded based on digital subtraction angiography during PCI. The number of patients with no-reflow and slow blood flow in each group was counted. Statistical analysis was performed based on data such as onset time, TIMI blood flow.

RESULTS

There were significant differences in thrombus components between the patients with acute ST-segment elevation myocardial infarction and non-ST-segment elevation myocardial infarction (P < 0.01). In the group with PCI < 3 h after onset of AMI, there was no significant difference in the incidence of no-reflow and slow-flow between the white and red thrombus groups. In the groups with PCI 3-6 and 6-12 h after onset of AMI, there was a significant difference in the incidence of no-reflow and slow-flow between the white and red thrombus groups (P < 0.01). There was a significant correlation between the onset time of AMI and the occurrences of no-reflow and slow blood flow during PCI (P < 0.01).

CONCLUSION

In direct PCI, the onset time of AMI and color of coronary thrombus are often used to predict whether there will be no reflow or slow blood flow after stent implantation.

Assessing and managing coronary microcirculation dysfunction in acute ST-segment elevation myocardial infarction

INTRODUCTION

Microvascular dysfunction in the setting of acute ST-segment elevation myocardial infarction (STEMI) is an indicator of poor long-term prognosis. Prompt assessment and pharmacological or procedural therapy (prophylactic or post onset of dysfunction) may improve outcomes in STEMI post-primary percutaneous intervention. Areas covered: The aim of this review is to provide a comprehensive analysis of the evidence available about the assessment and management of coronary microcirculatory injury/dysfunction in STEMI. We also aim to elucidate the possible strategies that could be applied in clinical practice to support the application of already available or novel therapeutic strategies for the prevention and management of microvascular impairment. Expert commentary: There are multiple established methods in assessing microvascular dysfunction, both non-invasively and invasively. Invasive physiological measurements allow real-time assessment of microvascular dysfunction and have prognostic cut-off values. Multiple therapeutic modalities exist for both preventing and treating microvascular dysfunction. These can be either pharmacological or mechanical, and there is no algorithm to guide if, how and when to apply them. Future research into both procedural and pharmacological therapy guided by physiological measurements is needed, with the aim of recognizing high-risk patients who would benefit from therapy.

Deflated Balloon-Facilitated Direct Stenting in Primary Angioplasty (The DBDS Technique): A Pilot Study

Background

Several studies and meta-analyses have shown that direct stenting (DS) may improve clinical outcomes in patients with acute ST-elevation myocardial infarction (STEMI). But in most cases, the thrombolysis in myocardial infarction (TIMI) flow remains ≤ 1 after wire placement. We used deflated balloon to facilitate DS in patients with totally occluded culprit arteries. The aim of this study was to evaluate the feasibility, safety and outcomes of this novel technique in patients with STEMI in real-world clinical practice.

Methods

This was a prospective, observational, single-center pilot study. From September 2016 to June 2018, 454 patients were enrolled in the study. DS was performed when the culprit vessel was visualized with at least TIMI flow grade 1. Patients with complete occlusion of the vessel after wire placement were subjected to deflated balloon-facilitated DS technique (DBDS technique) and DS was done wherever possible.

Results

DS was done in 74% (n = 336) of the patients and 26% (n = 118) patients received stenting after pre-dilatation (PD). DBDS technique to facilitate DS was successful in 68% patients (211/309). Final TIMI 3 flow was achieved more frequently in the DS group as compared to PD group (96.7% versus 92.3%, P = 0.04). The procedural complications were also significantly lower in DS group (0.6% versus 7.6%, P < 0.001). DS group had significantly lower procedure time (33 ± 19 min versus 41 ± 17 min, P < 0.001), fluoroscopy time (6.2 ± 3.4 min versus 7.8 ± 32 min, P < 0.001), required lesser contrast volume (112 ± 16 mL versus 123 ± 18 mL, P < 0.001) and had lower procedural cost (310 ± 45$ versus 402 ± 56$, P < 0.001). ST-segment resolution > 50% after percutaneous coronary intervention (PCI) were significantly higher in the DS group (85.7% versus 71.1%, P < 0.001). At 30 days, the major adverse cardiac event (MACE) rate was significantly lower in the DS group (2.4% versus 9.3%, P = 0.02), mainly driven by lower rates of target lesion revascularization (TLR) (0.9% versus 4.2%, P = 0.01).

Conclusion

This cost-effective technique appears to be simple, feasible and safe and is associated with superior clinical outcomes. It helps in maximizing DS and could offer an alternative to PD and aspiration thrombectomy in total occlusion. However, larger studies with longer follow up are required before a wider application of this technique.

Deferred vs Immediate Stenting in Primary Percutaneous Coronary Intervention: A Collaborative Meta-analysis of Randomized Trials With Cardiac Magnetic Resonance Imaging Data

BACKGROUND

The role of deferred vs immediate stenting during primary percutaneous coronary intervention (PCI) for patients with ST-segment elevation myocardial infarction (STEMI) remains controversial.

METHODS

We undertook a collaborative meta-analysis of study-level data by searching electronic scientific databases for investigations of primary PCI patients randomized to deferred or immediate stenting and subsequent cardiac magnetic resonance imaging. Primary angiographic and imaging outcomes were slow/no-reflow and microvascular obstruction (MVO), respectively. Main secondary outcome was recurrent ischemia.

RESULTS

Among 4 trials, a total of 1570 patients with STEMI were assigned to primary PCI with either deferred (n = 779) or immediate stenting (n = 791). Of these, 797 participants had analyzable cardiac magnetic resonance imaging examinations. Median clinical follow-up was 9 months. Patients treated with deferred stenting showed a lower risk of developing slow/no-reflow in the culprit vessel (risk ratio [RR], 0.54 [95% confidence interval (CI), 0.41-0.72]; P < 0.001), a similar risk for MVO (RR, 0.93 [95% CI, 0.76-1.14]; P = 0.51), and trended higher in the risk of recurrent ischemia (RR, 2.42 [95% CI, 0.88-6.63]; P = 0.09) compared with those treated with immediate stenting. The treatment effect for slow/no-reflow and MVO correlated with a thrombus score grade > 3 at the baseline angiography and with the total stent length implanted in the culprit artery.

CONCLUSIONS

A strategy of deferred stenting during primary PCI improves angiographic but not imaging or clinical outcomes compared with immediate stenting. The potential lower risk for myocardial injury by deferred stenting in primary PCI patients with STEMI and high thrombus burden requires a confirmation in adequately sized randomized trials.

Delayed vs. immediate stenting in STEMI with a high thrombus burden : A systematic review and meta-analysis

BACKGROUND

The results of several large-scale randomized controlled trials are controversial regarding the advantages of delayed stenting (DS) compared with immediate stenting (IS). We sought to determine whether DS has benefits for patients with ST-segment elevation myocardial infarction (STEMI) with a high thrombus burden compared with IS.

METHODS

We systematically searched four electronic databases. Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow, TIMI myocardial blush grade (TMBG), complete ST-segment resolution (>70%), major adverse cardiac events (MACE), and major bleeding complications were studied as outcomes. Data analysis was performed using a random-effects model utilizing the Review Manager 5.3 software.

RESULTS

Our meta-analysis included eight studies involving 744 patients. DS showed greater benefits than IS in terms of TIMI grade 3 flow (odds ratio [OR]: 5.09, 95% confidence interval [CI]: 1.98-13.02, p < 0.001), TMBG (OR: 4.17, 95% CI: 1.87-9.31, p < 0.001), complete ST-segment resolution (OR: 2.16, 95% CI: 1.36-3.43, p = 0.001), and MACE (OR: 0.48, 95% CI: 0.25-0.94, p = 0.03). No significant difference was observed regarding major bleeding events (OR: 1.76, 95% CI: 0.40-7.66, p = 0.45).

CONCLUSION

DS yielded satisfactory outcomes regarding myocardial tissue reperfusion, demonstrated by the improved TIMI flow grade, TMBG, complete ST-segment resolution, and decreased MACEs without increasing major bleeding events in patients with STEMI and a high thrombus burden. DS may be preferred to IS for treating patients with this characteristic presentation.