Distal embolization is common after directional atherectomy in coronary arteries and saphenous vein grafts

Saphenous graft atherosclerosis as assessed by optical coherence tomography data for stenotic and non-stenotic lesions from the OCTOPUS registry

Introduction

Coronary artery bypass grafting (CABG), although widely used for a long time in diffuse coronary artery disease (CAD), has serious limitations associated with graft aging and its degeneration.

Aim

The relationship between saphenous vein graft (SVG) plaque morphology assessed by optical coherence tomography (OCT) and clinical findings has not been elucidated yet.

Material and methods

We compared the morphology of SVG in stenotic vs. non-stenotic lesions using OCT imaging in 29 patients hospitalized in our center within the OCTOPUS registry.

Results

Stenotic lesions were characterized by higher incidence of thin-cap fibroatheroma (TCFA) (33% vs. 0%, p = 0.0048), thrombus (28% vs. 0%, p = 0.0008), lipid-rich plaque (LRP) (75% vs. 35%, p = 0.0013) and plaque within the SVG valve (19% vs. 0%, p = 0.0114) as compared to non-stenotic lesions. Patients with intimal tearing or rupture (ITR) were older (75.8% vs. 68.9 years, p = 0.047) and had lower left ventricular ejection fraction (LVEF) (32.0% vs. 49.7%, p = 0.001) and glomerular filtration rate (GFR) (36.0 vs. 73.6 ml/min/1.73 m², p = 0.010). Patients with calcified lesions vs. those without had lower high-density lipoprotein (HDL) cholesterol (33.2 vs. 44.1 mg/dl, p = 0.018), similarly to those with ruptured plaque vs. those without (28.3 vs. 41.7 mg/dl, p = 0.047).

Conclusions

Presence of ITR was associated with advanced age, decreased LVEF and renal insufficiency. Decreased concentration of HDL was associated with higher occurrence of calcified and ruptured plaque.

Early and midterm major adverse cardiac events in patient with saphenous vein graft using direct stenting or embolic protection device stenting

Background:

The treatment of an occluded saphenous vein graft (SVG) with percutaneous coronary intervention may encounter major adverse cardiac events (MACE). MACE rates have been reduced significantly by using the embolic protection device (EPD).

Objectives:

The aim of this study was to clarify the risks and the benefits of embolic protection devices.

Patients and Methods:

In a prospective, non-randomized observational study, patients aged 33 to 85 years old who underwent elective percutaneous coronary intervention due to SVG stenosis at our tertiary care center were enrolled between 2009 and 2011. The incidence rates of adverse events, including MACE, were obtained during the patients’ hospitalization and at 30-day and 6-month follow-up. MACE included death, Q-wave and non-Q-wave myocardial infarction, in-stent thrombosis, target lesion revascularization, and target vessel revascularization.

Results:

From 150 patients enrolled to the study, 128 (85.3%) patients underwent direct stenting and the rest underwent the EPD procedure. In-hospital MACE occurred in 17.2% of the patients in the direct stenting group versus only 9.1% in the EPD group (P = 0.530). MACE incidence was gradually increased at one and 6-month follow-up periods in the direct stenting group (19.5% and 21.9%, respectively), and remained unchanged in the EPD group (9.1% at six-month follow-up). Multivariate logistic regression model showed that the stenting procedure type could not predict early and midterm MACE with the presence of baseline characteristics as cofounders.

Conclusions:

Despite the considerable lower early and midterm MACE rates, numerically following the EPD procedure compared to direct stenting, the difference in the MACE rates between the two groups was not significant.

Effect of metoprolol on myocardial apoptosis after coronary microembolization in rats

BACKGROUND

Coronary microembolization (CME) is a serious complication following percutaneous coronary intervention (PCI) in patients with acute coronary syndromes. The use of metoprolol before PCI can significantly protect ischemic myocardium from myocardial damage, but the function of metoprolol in the treatment of CME is not entirely clear. This study was to explore the effect and significance of metoprolol on myocardial apoptosis and caspase-3 activation after CME in rats.

METHODS

Thirty rats were randomly divided into three groups including sham-operation (control group), CME plus saline (CME group), CME plus metoprolol (metoprolol group), 10 rats for each group. The CME group was induced by injecting 3 000 polyethylene microspheres (42 μm) into the left ventricle during a 10-second occlusion of the ascending aorta; the control group was injected with physiological saline instead of microembolization ball; the metoprolol or saline group was given three intravenous bolus injections before CME. Echocardiography, TUNEL staining, and Western blotting were used to evaluate cardiac function, proportion of apoptotic cells and activation of caspase-3 respectively at 6 hours after operation.

RESULTS

Echocardiographic parameters displayed that the metoprolol group improved cardiac function significantly compared with the CME group (P<0.05). The myocardial apoptotic rate of the CME group as well as the contents of activated caspase-3 increased significantly (P<0.05), both of which were ameliorated significantly by metoprolol treatment (P<0.05).

CONCLUSIONS

This study demonstrates that metoprolol can protect the myocardium during CME in rats by inhibiting apoptosis and improving cardiac function. These results suggest that the inhibition of apoptosis can be a potential therapeutic strategy for the treatment of CME.

Heterogeneity of Myocardial Perfusion in Distal Coronary Embolism with Different Particle Sizes

BACKGROUND

We hypothesized that altered myocardial perfusion distribution patterns could be seen with coronary distal emboli of different particle sizes using myocardial contrast echocardiography.

METHODS

In 16 open-chest anesthetized dogs, microsphere suspensions of 9 or 500 microm in diameter were injected into the left anterior descending coronary artery until the mean left anterior descending coronary artery flow rate was reduced to less than 30% of baseline flow. During baseline conditions and after maximal embolization, real-time myocardial contrast echocardiography was performed by intravenous infusion of an echocontrast agent.

RESULTS

In animals infused with 9-microm microspheres, a transmural perfusion defect was seen at the time of maximal embolization. In contrast, in animals infused with 500-microm microspheres, a subendocardial perfusion defect was observed.

CONCLUSIONS

The particle size of coronary distal emboli affects myocardial perfusion distribution.

Determinants of 30-day adverse events following saphenous vein graft intervention with and without a distal occlusion embolic protection device

Distal balloon occlusion was approved as a means of embolic protection during saphenous vein graft intervention based on its ability to decrease major adverse clinical events (MACEs) by 42% in the 801-patient Saphenous Vein Graft Angioplasty Free of Emboli Randomized (SAFER) trial. However, the cost and technical complexity of this device have limited its widespread use and prompted some to avoid its use in cases that appear at "low risk" for complications. If predictors of MACEs and their potential decrease by distal balloon occlusion could be identified, this would have important clinical implications in this challenging population. We therefore used standard demographic and angiographic variables and 2 new angiographic markers (extent of graft degeneration and estimated volume of plaque in the target lesion) to construct multivariable logistic regression models of 30-day of MACEs in the SAFER trial. Independent correlates of increased 30-day MACEs were more extensive vein graft degeneration (p = 0.0001) and bulkier lesions (larger estimated plaque volume, p = 0.0005). Use of a distal balloon occlusion device was independently predictive of lower 30-day rates of MACE (p = 0.01), with uniform benefit across risk strata (no significant interaction between device use and independent angiographic risk factors). Thus, the risk of 30-day MACEs after percutaneous intervention in aortocoronary saphenous vein grafts is increased in more diffusely diseased grafts and in bulkier lesions, but a significant benefit of the GuardWire was seen across all levels of MACE risk rather than just those perceived to be at highest risk.

Impact of embolization during coronary artery bypass grafting on outcome and length of stay

BACKGROUND

Transcranial Doppler ultrasonography detects emboli in most patients during coronary artery bypass grafting. However, the significance of these emboli has not yet been established.

METHODS

We monitored 82 patients during coronary artery bypass grafting with this technique and related the numbers of emboli to the outcomes and length of hospital stay.

RESULTS

We detected cerebral emboli in all patients. Patients with stroke (n = 4; 4.9%) had a mean of 449 emboli, as compared with 169 emboli in patients without stroke (n = 78) (p = 0.005). Patients with major cardiac complications (n = 7) had a mean of 392 emboli, as compared with 163 in patients without such complications (n = 75) (p = 0.003). The mean hospital stay of survivors was 8.6 days in patients with fewer than 100 emboli (n = 40), 13.5 days in patients with 101 to 300 emboli (n = 23), 16.3 days in those with 301 to 500 emboli (n = 16), and 55.8 days in patients with more than 500 emboli (n = 6) (p = 0.0007). This relation was unchanged when patients with complications were excluded. The correlation between embolization and outcome was independent of the extent of aortic atheroma or age.

CONCLUSIONS

Emboli detected during coronary artery bypass grafting are significantly related to major cardiac and neurologic complications and affect length of stay in all patients, even in the absence of such specific complications.