Frequency, predictors, and effect of the slow-flow phenomenon after drug-coated balloon angioplasty for femoropopliteal lesions.

Drug-coated balloon (DCB) angioplasty for femoropopliteal (FP) lesions has been available in Japan since 2018. In daily practice, we encountered cases of the slow-flow phenomenon after DCB angioplasty. However, no data regarding the slow-flow phenomenon after DCB angioplasty for FP lesions are available. This study aimed to investigate the frequency, predictors, and effect of the slow-flow phenomenon following DCB angioplasty for FP lesions. This single-center, retrospective, observational study analyzed 88 FP lesions treated by DCB angioplasty between April 2018 and July 2019. Patients were divided into the slow-flow group (n = 7) and non-slow-flow group (n = 81) and were analyzed. The primary endpoint was primary patency at 6 months. The slow-flow phenomenon was observed in seven cases (8.0%). The slow-flow group had higher incidence rates of critical limb ischemia (CLI) (71% vs. 25%, p < 0.01), chronic total occlusion (CTO) lesions (86% vs. 26%, p < 0.01), and poor tibial vessel runoff (86% vs. 33%, p < 0.01) and had a longer DCB length (237 ± 56 mm vs. 159 ± 97 mm, p = 0.03) than the non-slow-flow group. The primary patency rate at 6 months was 71% in the slow-flow group and 91% in the non-slow-flow group (p = 0.09). The rate of freedom from target lesion revascularization at 6 months was 71% in the slow-flow group and 97% in the non-slow-flow group (p < 0.01). The amputation-free survival rate at 6 months was 71% and 95% (p = 0.02), whereas the survival rate at 6 months was 71% and 95% (p = 0.02). The incidence rate of the slow-flow phenomenon after DCB angioplasty for FP lesions was 8.0%. CLI, a CTO lesion, poor tibial vessel runoff, and total DCB length were associated with the slow-flow phenomenon. Our results indicate that the slow-flow phenomenon is associated with poor short-term clinical outcomes.

Repeated occurrence of slow flow phenomenon during and late after sirolimus-eluting stent implantation.

A 78-year-old man with unstable angina showed 90% stenosis in the proximal left anterior descending artery. Pre-procedural intravascular ultrasound revealed ruptured plaque and attenuated plaque in the lesion. Under these conditions, two overlapping sirolimus-eluting stent (SES) implantation in this lesion resulted in slow flow which was recovered by intracoronary nitrates, nicorandil, and nitroprusside without further complications. When the patient showed up again 5 years later with recurrence of angina pectoris, angiography revealed a hazy ulcerated in-stent restenosis (ISR) at the site of the SES. Pre-procedural optical coherence tomography (OCT) imaging revealed multiple intimal ruptures, cavity formation behind the stent struts, a thin-cap fibroatheroma containing neointima surrounded by signal-poor, lipid-rich area in the proximal SES, suggesting the progression of neoatherosclerosis within SES. Importantly, there occurred slow flow again after balloon angioplasty for this lesion. We would suggest careful OCT examination is warranted to confirm development of neoatherosclerosis within the stent, and distal protection device should be considered to prevent slow flow phenomenon even in a patient with very late ISR.

Slow-flow phenomenon after drug-coated balloon angioplasty for lower-extremity arteries is associated with lack of prescribing of calcium channel blockers.

This study aimed to investigate the relationship between prescription drugs and the slow-flow phenomenon after drug-coated balloon angioplasty. Of 30 patients, five (17%) presented with the slow-flow phenomenon. Patients with the slow-flow phenomenon were significantly less commonly prescribed calcium channel blockers than those without the slow-flow phenomenon (P = 0.03). There was no intergroup difference in the prescription of angiotensin II receptor blockers and ß-blockers. The clinical outcomes, including restenosis, thrombosis, target lesion revascularization, and death, did not differ between groups during the 10-month observation period.

Effect of MGuard net protective stent on the release of troponin I in patients with acute coronary syndromes. A randomized controlled trial.

This study was designed to determine whether the treatment of patients with unstable angina pectoris or non-Q-wave myocardial infarction with a stent containing a protection net to prevent coronary microembolization affects the severity of biomarker release.The MGuard stent (InspireMD, Tel Aviv, Israel) was designed as a plaque/thrombus-trapping device, using a conventional bare metal stent covered with an ultrathin, flexible mesh net. We hypothesized that this stent would partly eliminate distal embolization and decrease subsequent troponin I (TnI) release.Forty-six acute coronary syndrome patients referred for percutaneous coronary intervention (PCI) were included and randomized in this study. Serum concentrations of TnI were measured prior to, as well as 24 and 48 hours after, the PCI procedure.Technical success was 95% and 100% in the MGuard group and non-MGuard group, respectively. A transient no-reflow phenomenon was observed in one interventional procedure in each group of patients (5% versus 4%; NS). Two patients (one in each group) died during the hospital stay. There was no statistically significant difference in median postprocedural TnI levels in either group.The results suggest that coronary stenting with a stent system containing a protection net to prevent coronary microembolization (eg the MGuard stent) in patients with acute coronary syndromes does not decrease procedural myocardial injury, as measured by TnI release. It seems likely that stenting with the MGuard stent is feasible, however, its safety should be verified in larger studies.

A Translational Study of a New Therapeutic Approach for Acute Myocardial Infarction: Nanoparticle-Mediated Delivery of Pitavastatin into Reperfused Myocardium Reduces Ischemia-Reperfusion Injury in a Preclinical Porcine Model.

BACKGROUND: There is an unmet need to develop an innovative cardioprotective modality for acute myocardial infarction, for which interventional reperfusion therapy is hampered by ischemia-reperfusion (IR) injury. We recently reported that bioabsorbable poly(lactic acid/glycolic acid) (PLGA) nanoparticle-mediated treatment with pitavastatin (pitavastatin-NP) exerts a cardioprotective effect in a rat IR injury model by activating the PI3K-Akt pathway and inhibiting inflammation. To obtain preclinical proof-of-concept evidence, in this study, we examined the effect of pitavastatin-NP on myocardial IR injury in conscious and anesthetized pig models. METHODS AND RESULTS: Eighty-four Bama mini-pigs were surgically implanted with a pneumatic cuff occluder at the left circumflex coronary artery (LCx) and telemetry transmitters to continuously monitor electrocardiogram as well as to monitor arterial blood pressure and heart rate. The LCx was occluded for 60 minutes, followed by 24 hours of reperfusion under conscious conditions. Intravenous administration of pitavastatin-NP containing ≥ 8 mg/body of pitavastatin 5 minutes before reperfusion significantly reduced infarct size; by contrast, pitavastatin alone (8 mg/body) showed no therapeutic effects. Pitavastatin-NP produced anti-apoptotic effects on cultured cardiomyocytes in vitro. Cardiac magnetic resonance imaging performed 4 weeks after IR injury revealed that pitavastatin-NP reduced the extent of left ventricle remodeling. Importantly, pitavastatin-NP exerted no significant effects on blood pressure, heart rate, or serum biochemistry. Exploratory examinations in anesthetized pigs showed pharmacokinetic analysis and the effects of pitavastatin-NP on no-reflow phenomenon. CONCLUSIONS: NP-mediated delivery of pitavastatin to IR-injured myocardium exerts cardioprotective effects on IR injury without apparent adverse side effects in a preclinical conscious pig model. Thus, pitavastatin-NP represents a novel therapeutic modality for IR injury in acute myocardial infarction.

The role of MGuard stent in primary coronary angioplasty.

In a significant proportion of percutaneous coronary interventions (PCI) performed in the setting of acute myocardial infarction, despite apparently adequate restoration of blood flow in the target epicardial vessel, optimal myocardial reperfusion at tissue level is not achieved. This phenomenon, defined as no-reflow, has been consistently associated with negative outcomes; it involves many pathogenetic factors, including microvascular dysfunction and embolization of thrombus and plaque debris from the culprit lesion during PCI, particularly during stent deployment. Several strategies - either pharmacological or mechanical - have been developed in order to prevent or reduce the incidence of no-reflow, but this phenomenon still remains a major issue in primary coronary intervention. The MGuard stent is a relatively new device intended to ameliorate tissue reperfusion by reducing distal embolization: it consists of a balloon-expandable, bare metal stent platform, whose outer surface is covered by a mesh of polyethylene terephthalate (PET), so that after expansion the thrombus is entrapped between the stent struts and the vessel wall. This stent has been tested in lesions with a high embolic risk, as on vein grafts or in the setting of acute coronary syndromes. In this paper, we will review and discuss the data available about this device, with a particular focus on its use in primary PCI.