Spontaneous and procedural plaque embolisation in native coronary arteries: pathophysiology, diagnosis, and prevention

Preconditioning with selective autoretroperfusion: In vivo and in silico evidence of washout hypothesis

Introduction

Prompt reperfusion of coronary artery after acute myocardial infarction (AMI) is crucial for minimizing heart injury. The myocardium, however, may experience additional injury due to the flow restoration itself (reperfusion injury, RI). The purpose of this study was to demonstrate that short preconditioning (10 min) with selective autoretroperfusion (SARP) ameliorates RI, based on a washout hypothesis.

Methods

AMI was induced in 23 pigs (3 groups) by occluding the left anterior descending (LAD) artery. In SARP-b (SARP balloon inflated) and SARP-nb (SARP balloon deflated) groups, arterial blood was retroperfused for 10 min via the great cardiac vein before releasing the arterial occlusion. A mathematical model of coronary circulation was used to simulate the SARP process and evaluate the potential washout effect.

Results

SARP restored left ventricular function during LAD occlusion. Ejection fraction in the SARP-b group returned to baseline levels, compared to SARP-nb and control groups. Infarct area was significantly larger in the control group than in the SARP-b and SARP-nb groups. End-systolic wall thickness was preserved in the SARP-b compared to the SARP-nb and control groups. Analyte values (pH, lactate, glucose, and others), measured every 2 min during retroperfusion, suggest a "washout" effect as one important mechanism of action of SARP in reducing infarct size. With SARP, the values progressively approached baseline levels. The mathematical model also confirmed a possible washout effect of tracers.

Discussion

RI can be ameliorated by delaying restoration of arterial flow for a brief period of time while pretreating the infarction with SARP to restore homeostasis via a washout mechanism.

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.

Culprit Lesion Morphology of Rapidly Progressive and Extensive Anterior-Wall ST-Segment Elevation Myocardial Infarction

BACKGROUND

Rapidly progressive, extensive myocardial injury/infarction (RPEMI) beyond the concept of wave-front phenomenon can be observed even when achieving timely reperfusion; however, the pathogenesis of RPEMI remains unknown. This retrospective study investigated clinical and lesion characteristics of RPEMI, focusing on culprit-lesion morphology (CLM).

METHODS

Among patients with extensive anterior-wall ST-segment elevation myocardial infarction due to proximal left anterior descending artery lesions who had reperfusion within 3 hours of symptom onset, 60 patients undergoing both intravascular ultrasound and cardiac magnetic resonance imaging were enrolled. Myocardial injury/infarction before reperfusion therapy was assessed by QRS scores at hospitalization electrocardiogram, and the extent of myocardial injury/infarction was evaluated by cardiac magnetic resonance imaging, which measured area at risk, infarct size, myocardial salvage index, microvascular obstruction, and left ventricular ejection fraction. RPEMI was defined as lower left ventricular ejection fraction (less median value) with microvascular obstruction.

RESULTS

Despite comparable onset-to-door and onset-to-reperfusion times and area at risk, patients with RPEMI showed higher QRS scores at hospitalization (5 [4.3-6] versus 3 [2-4], P<0.001) and infarct size (26.5±9.1 versus 20.4±10.5%, P=0.04), and a tendency toward lower myocardial salvage index (0.27±0.14 versus 0.36±0.20, P=0.10) compared with those without. Patients with versus without RPEMI more frequently observed specific CLM on intravascular ultrasound, characterized by the combination of vulnerable plaques, plaque ruptures, and/or large thrombi. When stratified by CLM-score composed of these 3 criteria, higher CLM-scores were or tended to be associated with higher QRS scores and incidence of RPEMI. In multivariate analyses including no-reflow phenomenon and final coronary-flow deterioration, increased CLM-score (≥2) was independently associated with high QRS scores and RPEMI (odd ratio 11.25 [95% CI, 2.43-52.00]; P=0.002).

CONCLUSIONS

Vulnerable CLM was a consistent determinant of advanced myocardial injury/infarction both before and after reperfusion therapy and may play a pivotal role in the development of RPEMI.

[The no-Reflow Phenomenon During Primary Percutaneous Coronary Intervention in Patients With ST-Segment Elevation Myocardial Infarction due to Massive Coronary Thrombosis. Pathogenesis and Predictors of no-Reflow]

Despite successful and timely revascularization of the infarct-related artery, myocardial tissue remains underperfused in some patients. This condition is known as the no-reflow phenomenon, which is associated with a worse prognosis. The first part of the systematic review on no-reflow focuses on description of the no-reflow pathogenesis and predictors. This phenomenon has a complicated, multifactorial pathogenesis, including distal embolization, ischemic injury, reperfusion injury, and a component of individual predisposition. Meanwhile, this phenomenon undergoes spontaneous regression in some patients. Several studies have demonstrated the role of definite biomarkers and clinical indexes as risk predictors for no-reflow. The significance of each pathogenetic component of no-reflow is suggested to be different in different patients, which may warrant an individualized approach in the treatment.

ALT-to-Lymphocyte Ratio as a Predictor of Long-Term Mortality in Patients with Normal Liver Function Presenting Coronary Artery Disease after Undergoing PCI: A Retrospective Cohort Study

Background

Alanine aminotransferase (ALT) is referred as liver transaminase and predominantly expressed by hepatocytes. Previous evidences showed that high levels of ALT were reversely associated with short- and long-term outcomes in patients with myocardial infarction. Besides, low lymphocyte has been demonstrated to be significantly correlated with adverse clinical outcomes in coronary artery disease (CAD). However, evidences about the relationship between ALT-to-lymphocyte ratio (ALR) and outcomes in CAD patients with normal liver function are limited. The aim of this study was to assess the relationship between ALR and clinical outcomes in patients with CAD.

Methods

This is a retrospective cohort study, and a total of 3561 patients were enrolled in Clinical Outcomes and Risk Factors of Patients with CAD after percutaneous coronary intervention (PCI), from January 2013 to December 2017. After excluding patients with liver dysfunction, we finally enrolled 2714 patients. These patients were divided into two groups according to ALR value: the lower group (ALR < 14.06, n = 1804) and the higher group (ALR ≥ 14.06, n = 910). The average follow-up time was 37.59 ± 22.24 months.

Results

We found that there were significant differences between the two groups in the incidence of all-cause mortality (ACM) (P < 0.001) and cardiac mortality (CM) (P=0.010). Kaplan–Meier survival analysis suggested that CAD patients with higher ALR tended to have an increased accumulated risk of ACM and CM (log rank P < 0.001 and P=0.006, respectively). Multivariate Cox regression analysis showed that ALR was an independent predictor of ACM (hazard ratio (HR) = 2.017 (95% confidence interval (CI): 1.289–3.158), P=0.002) and CM (HR = 1.862 (95% CI: 1.047–3.313), P=0.034). We did not find significant difference in the incidence of major adverse cardiovascular events (MACEs) and major adverse cardiovascular and cerebrovascular events (MACCEs) between the two groups after adjustments of confounders.

Conclusion

Our results indicate that ALR is an independent predictor of long-term adverse outcomes in CAD patients who underwent PCI.

Pyrrolidine Dithiocarbamate Attenuates Cardiocyte Apoptosis and Ameliorates Heart Failure Following Coronary Microembolization in Rats

Background

Nuclear factor-kB is highly activated in cardiovascular disorders. However, few articles have targeted at the role of nuclear factor-kB inhibitor in heart failure.

Aims

To evaluate the effects of nuclear factor-kB inhibitor pyrrolidine dithiocarbamate on cardiocyte apoptosis and cardiac function in a rat heart failure model.

Study Design

Animal experiment.

Methods

A stable and reproducible rat heart failure model (n=64) was prepared by injecting homologous microthrombotic particles into the left ventricle of Sprague–Dawley rats while obstructing the ascending aorta to produce coronary microembolization. Rats with heart failure were randomized into untreated (HFu) and pyrrolidine dithiocarbamate-treated (HFp) groups; the latter received an intraperitoneal injection of pyrrolidine dithiocarbamate (100 mg/kg/day) 1 h prior to surgery as well as on postoperative days 1-7. The sham group comprised 32 Sprague–Dawley rats. Eight rats from each group were sacrificed on days 1, 3, 7, and 14 postoperatively. Masson’s trichrome staining was used to determine the micro-fibrotic area to indicate the severity of myocardial loss. Terminal transferase uridine triphosphate nick end labeling staining was used to detect apoptotic cardiomyocytes. Echocardiography and hemodynamics were performed to evaluate left ventricular function.

Results

Rats with heart failure exhibited pathological changes evidenced by patchy myocardial fibrosis, remarkably elevated severity of myocardial loss, and persistently reduced left ventricular function. At the end of the study, compared with the HFu group, myocardial infarct size was reduced by 28% (p=0.001), cardiocyte apoptosis was suppressed (7.17%±1.47% vs 2.83%±0.75%, p<0.001), cardiac function parameters such as left ventricular ejection fraction (80%±4% vs 61%±6%), left ventricular + dP/dt max (4828±289 vs 2918±76 mmHg.s−1), left ventricular - dP/dt max (4398±269 vs 2481±365 mmHg.s−1), and left ventricular systolic pressure (126±13 vs 100±10 mmHg) were significantly increased, and left ventricular end-diastolic pressure was reduced (18±2 vs 13±1 mmHg) (p<0.001, for all) in the HFu group.

Conclusion

Our rat model can adequately mimic heart failure via coronary vessel embolization. Moreover, pyrrolidine dithiocarbamate treatment can reduce cardiocyte apoptosis and improve cardiac function, which may be beneficial for patients with heart failure secondary to myocardial infarction.