Effectiveness of adjunctive stent implantation following directional coronary atherectomy for treatment of left anterior descending ostial stenosis

Myocardial infarction in rats was alleviated by MSCs derived from the maternal segment of the human umbilical cord

Background

Mesenchymal stem cells (MSCs) are safe and effective in treating myocardial infarction (MI) and have broad application prospects. However, the heterogeneity of MSCs may affect their therapeutic effect on the disease. We recently found that MSCs derived from different segments of the same umbilical cord (UC) showed significant difference in the expression of genes that are related to heart development and injury repair. We therefore hypothesized that those MSCs with high expression of above genes are more effective to treat MI and tested it in this study.

Methods

MSCs were isolated from 3 cm-long segments of the maternal, middle and fetal segments of the UC (maternal-MSCs, middle-MSCs and fetal-MSCs, respectively). RNA-seq was used to analyze and compare the transcriptomes. We verified the effects of MSCs on oxygen-glucose deprivation (OGD)-induced cardiomyocyte apoptosis in vitro. In vivo, a rat MI model was established by ligating the left anterior descending coronary artery, and MSCs were injected into the myocardium surrounding the MI site. The therapeutic effects of MSCs derived from different segments of the UC were evaluated by examining cardiac function, histopathology, cardiomyocyte apoptosis, and angiogenesis.

Results

Compared to fetal-MSCs and middle-MSCs, maternal-MSCs exhibited significantly higher expression of genes that are associated with heart development, such as GATA-binding protein 4 (GATA4), and myocardin (MYOCD). Coculture with maternal-MSCs reduced OGD-induced cardiomyocyte apoptosis. In rats with MI, maternal-MSCs significantly restored cardiac contractile function and reduced the infarct size. Mechanistic experiments revealed that maternal-MSCs exerted cardioprotective effects by decreasing cardiomyocyte apoptosis, and promoting angiogenesis.

Conclusion

Our data demonstrated that maternal segment-derived MSCs were a superior cell source for regenerative repair after MI. Segmental localization of the entire UC when isolating hUCMSCs was necessary to improve the effectiveness of clinical applications.

Can the outcomes of mesenchymal stem cell-based therapy for myocardial infarction be improved? Providing weapons and armour to cells

Use of mesenchymal stem cell (MSC) transplantation after myocardial infarction (MI) has been found to have infarct-limiting effects in numerous experimental and clinical studies. However, recent meta-analyses of randomized clinical trials on MSC-based MI therapy have highlighted the need for improving its efficacy. There are two principal approaches for increasing therapeutic effect of MSCs: (i) preventing massive MSC death in ischaemic tissue and (ii) increasing production of cardioreparative growth factors and cytokines with transplanted MSCs. In this review, we aim to integrate our current understanding of genetic approaches that are used for modification of MSCs to enable their improved survival, engraftment, integration, proliferation and differentiation in the ischaemic heart. Genetic modification of MSCs resulting in increased secretion of paracrine factors has also been discussed. In addition, data on MSC preconditioning with physical, chemical and pharmacological factors prior to transplantation are summarized. MSC seeding on three-dimensional polymeric scaffolds facilitates formation of both intercellular connections and contacts between cells and the extracellular matrix, thereby enhancing cell viability and function. Use of genetic and non-genetic approaches to modify MSC function holds great promise for regenerative therapy of myocardial ischaemic injury.

Integration of mesenchymal stem cells with nanobiomaterials for the repair of myocardial infarction

The integration of nanobiomaterials with stem cells represents a promising strategy for the treatment of myocardial infarction. While stem cells and nanobiomaterials each demonstrated partial success in cardiac repair individually, the therapeutic efficacy of the clinical settings for each of these has been low. Hence, a combination of nanobiomaterials with stem cells is vigorously studied to create synergistic effects for treating myocardial infarction. To date, various types of nanomaterials have been incorporated with stem cells to control cell fate, modulate the therapeutic behavior of stem cells, and make them more suitable for cardiac repair. Here, we review the current stem cell therapies for cardiac repair and describe the combinatorial approaches of using nanobiomaterials and stem cells to improve therapeutic efficacy for the treatment of myocardial infarction.

Mesenchymal stem cell therapy for heart disease

Mesenchymal stem cells (MSC) are adult stem cells with capacity for self-renewal and multi-lineage differentiation. Initially described in the bone marrow, MSC are also present in other organs and tissues. From a therapeutic perspective, because of their easy preparation and immunologic privilege, MSC are emerging as an extremely promising therapeutic agent for tissue regeneration and repair. Studies in animal models of myocardial infarction have demonstrated the ability of transplanted MSC to engraft and differentiate into cardiomyocytes and vascular cells. Most importantly, engrafted MSC secrete a wide array of soluble factors that mediate beneficial paracrine effects and may greatly contribute to cardiac repair. Together, these properties can be harnessed to both prevent and reverse remodeling in the ischemically injured ventricle. In proof-of-concept and phase I clinical trials, MSC therapy improved left ventricular function, induced reverse remodeling, and decreased scar size. In this review we will focus on the current understanding of MSC biology and MSC mechanism of action in cardiac repair.

Directional coronary atherectomy: a time for reflection. Should we let it go?

A series of interventional tools have emerged since the advent of percutaneous coronary angioplasty. Several are fundamental and used routinely, while others less favourable have fallen short of mainstream therapy and/or have settled as a niche device. We present an overview of the evolution of directional coronary atherectomy (DCA), a unique device that was originally conceived in 1984 to solve the limitations of balloon angioplasty. Unfortunately, we have witnessed its use fall significantly out of favour due to premature and controversial study results. In many interventional laboratories DCA is no longer available. However, we strongly feel that allowing DCA to join the list of extinct interventional tools would be very unfortunate. We, herein, present a series of complex percutaneous coronary procedures to illustrate the convenience of DCA use as a lesion-specific niche device. Finally, DCA offers a valuable distinct clinical research function as it allows for in vivo pathological coronary tissue examination. In conclusion, we plead for its continued production and use as an interventional niche device for the wellbeing of our patients.

Drug-eluting stents for the treatment of ostial coronary lesions: comparison of sirolimus-eluting stent with paclitaxel-eluting stent

BACKGROUND

Treatment of ostial coronary lesions represents a challenge for interventional cardiologists. The efficacy of drug-eluting stents (DES) has been demonstrated as improving the outcomes of patients in a few studies. It is not known, however, which DES, sirolimus-eluting stent (SES) versus paclitaxel-eluting stent (PES), is superior for the treatment of ostial lesions.

METHODS

In this retrospective study, 95 consecutive patients with de-novo ostial lesions underwent coronary SES (n=47, lesions=48) or PES implantation (n=45, lesions=47), and quantitative coronary analysis was performed at the time of stent implantation and subsequently at 8 months post stenting. Ostial lesion was defined as > or =50% diameter stenosis rising within 3 mm of either left anterior descending coronary artery or left circumflex artery or right coronary artery measured by quantitative coronary analysis. Major adverse cardiac events including death, thrombosis, nonfatal myocardial infarction, and target lesion revascularization were compared between the two groups.

RESULTS

Baseline clinical and angiographic characteristics were well balanced between the two groups. At 8 months clinical and angiographic follow-up, overall major adverse cardiac events and target lesion revascularization rates were similar in both groups (6.4 vs. 11.2%, P=0.184; 4.3 vs. 8.9%, P=0.170, respectively). The in-stent and in-segment restenosis were, however, significantly higher in PES group compared with SES group (15.5 vs. 0%, P=0.001; 22.2 vs. 4.3%, P=0.003). Similarly, the late loss in both in-stent and in-segment was significantly higher in the PES group than in SES group (0.65+ or -0.67 vs. 0.16+ or -0.18 mm; 0.68+ or -0.65 vs. 0.15+ or -0.12 mm; P<0.001, respectively).

CONCLUSION

In this small sample-size, nonrandomized, and nonprospective study, the data indicated that implantation of DES appears safe and effective for the treatment of patients with de-novo ostial coronary lesions, but SES implantation showed more favorable results in respect of restenosis compared with PES implantation.

Sirolimus-eluting stent implantation for treatment of proximal left anterior descending coronary artery lesions: long-term outcome and predictors of adverse cardiac events

OBJECTIVES

Acute and long-term results after sirolimus-eluting stent (SES) implantation of proximal left anterior descending coronary artery (LAD) disease were evaluated.

BACKGROUND

Although SES has been used increasingly for the treatment of LAD disease, data regarding their safety and efficacy in a real-world population are limited.

METHODS

We investigate the short- and long-term results in 966 patients who underwent SES implantation for stenosis of proximal LAD.

RESULTS

The procedural success rate was 97.6%, and procedural non-Q-wave myocardial infarction (MI) rate was 14.5%. In-hospital major complications occurred in five patients (0.5%), including three deaths and two Q-wave MIs. During follow-up (20.4 +/- 8.9 months), there were 16 deaths (1.7%; 10 cardiac, 6 noncardiac), 2 Q-wave MIs, and 22 target lesion revascularizations (2.3%). Late stent thrombosis occurred in two patients (0.2%), 14 and 23 months after the procedure. The event-free survival rates for cardiac death/Q-wave MI were 98.6% +/- 0.4% at 1 year and 97.8% +/- 0.6% at 2 years. The cumulative probabilities of survival without major adverse cardiac events (MACE) were 96.7% +/- 0.6% at 1 year and 95.4% +/- 0.8% at 2 years. In multivariate analysis, stented length (HR 1.04, 95%CI 1.01-1.07, P = 0.009) and infarct-related artery (HR 5.18, 95%CI 1.09-24.64, P = 0.039) were independently related to cardiac death/Q-wave MI. In addition, stented length (HR 1.04, 95%CI 1.02-1.06, P < 0.001) and left ventricular dysfunction (HR 2.66, 95%CI 1.07-6.63, P = 0.036) were significant independent predictors of MACE.

CONCLUSIONS

SES implantation for proximal LAD disease appears safe and effective in a real-world population, and the independent predictors of MACE included stented length and left ventricular dysfunction.

A Novel Design of a Noncylindric Stent With Beneficial Effects on Flow Characteristics: An Experimental and Numerical Flow Study in an Axisymmetric Arterial Model With Sequential Mild Stenoses

The objective of this study was to investigate whether a novel noncylindric "stent," implanted upstream of one or more mild arterial stenoses could be beneficial, by increasing in-stent wall shear stresses (WSS) and by limiting the flow recirculation zones in the vicinity of the stenoses. An in vitro model employing flow visualization, and computational fluid dynamics were used for the study of steady and unsteady flow fields in a model of a coronary artery with two sequential 50% stenoses. Two different tube-entrance geometries (a cylindric and a convergent nozzle), modeling an ostial stented arterial segment, were studied regarding their effect on flow patterns and WSS at various Reynolds numbers (Re = 200-800). In this preliminary study, the internal walls of these tube entrance geometries were smooth, not taking into account the roughness of the actual stent's strut. "In-stent" WSS was significantly increased at the noncylindric configuration compared to that in the regular cylindric geometry. The difference of the spatially averaged "in-stent" WSS between the two designs gradually increased with the increase in Re, reaching a peak value up to 50% in the case of the noncylindric endovascular device, for the examined Re range. For the same configuration, both the experimental and numerical analyses indicated a decrease in flow recirculation region at the vicinity distally to a sequential stenosis up to 6%, and the mean flow velocity was increased for both steady and pulsatile flow. These effects of the new "stent" configuration could be important for the delay of restenosis processes and should be further investigated in vivo.

Buddy wire technique for stent placement at non-aorto ostial coronary lesions

Percutaneous coronary intervention (PCI) of coronary non-aorto ostial lesions offers technical challenges not encountered with other lesion sub types. Stenting of these lesions improves acute angiographic result and lowers the rate of restenosis. However, precise stent placement at non-aorto ostial lesions is technically difficult with risk of incomplete lesion coverage or jailing of the main branch. In this report, we describe a buddy wire technique to facilitate precise stent placement at non-aorto ostial lesions.

Early outcome of treatment of ostial de novo left anterior descending coronary artery lesions with drug-eluting stents

We investigated early and mid-term clinical and angiographic outcomes of patients who had de novo ostial left anterior descending coronary artery (LAD) lesions that were treated with drug-eluting stents (DESs) or bare metal stents (BMSs). We identified 43 consecutive patients who underwent percutaneous intervention for isolated de novo ostial LAD lesions with implantation of DESs and compared them with 43 patients who had similar lesions that were treated with BMSs. All stents were successfully implanted. There were no significant differences with respect to major in-hospital complications between the 2 groups. One patient in the BMS group died during hospitalization. Non-Q-wave myocardial infarction occurred in 2 patients (4.7%) in the DES and in 1 patient (2.3%) in the BMS group. At 9-month follow-up, 3 patients (7%) in the DES group and 11 (25.6%) in the BMS group underwent target lesion revascularization (p = 0.038); major adverse cardiac events were less frequent in the DES than in the BMS group (9.3% vs 32.6%, p = 0.015). Angiographic follow-up was available in 82% of patients in the DES group and 75% of those in the BMS group (p = 0.6) and showed lower binary restenotic rates (5.7% vs 31.3%, p = 0.01) and smaller late loss (0.30 +/- 0.81 vs 1.23 +/- 0.93 mm, p = 0.0001) in the DES group. In conclusion, DES implantation in de novo ostial LAD lesions appears safe and effective and is associated with a significant decrease in restenotic rates compared with historical experience with BMSs.

Effectiveness of Sirolimus-Eluting Stent Implantation for the Treatment of Ostial Left Anterior Descending Artery Stenosis With Intravascular Ultrasound Guidance

OBJECTIVES

This study was designed to evaluate the clinical and angiographic outcomes of sirolimus-eluting stent (SES) implantation for ostial left anterior descending (LAD) lesions compared with bare-metal stent (BMS) implantation.

BACKGROUND

The effectiveness of SES implantation for ostial LAD lesions is currently unknown.

METHODS

Sirolimus-eluting stents were implanted in 68 consecutive patients with ostial LAD stenoses. The control group was composed of 77 patients treated with BMS during the preceding two years. In the SES group, for complete lesion coverage, stent positioning was intentionally extended into the distal left main coronary artery (LMCA) in 23 patients (34%) with intermediate LMCA narrowing.

RESULTS

Compared with the BMS group, the SES group had more multivessel involvement, received fewer debulking atherectomies, underwent more direct stenting, had a greater number of stents, and had more segments stented. The procedural success rate was 100% in both groups. The six-month angiographic restenosis rate was significantly lower in the SES group than in the BMS group (5.1% vs. 32.3%, p < 0.001). During the one-year follow-up period, neither death nor myocardial infarction occurred in either group, but target lesion revascularization was less frequent in the SES group than in the BMS group (0% vs. 17%, p < 0.001). In the SES group, there were no restenoses in cases with LMCA coverage, compared with three restenoses (7.9%) in cases with precise stent positioning (p = NS).

CONCLUSIONS

Sirolimus-eluting stent implantation in ostial LAD lesions achieved excellent results regarding restenosis and clinical outcomes compared with BMS implantation. This finding may be associated with reduced neointimal hyperplasia and complete lesion coverage.

Directional coronary atherectomy plus stent implantation vs. left internal mammary artery bypass grafting for isolated proximal stenosis of the left anterior descending coronary artery

The aim of this study was to compare the short- (< 30 days) and long-term (> or = 30 days) clinical outcomes of left internal mammary artery bypass grafting (LIMA-LAD) and directional coronary atherectomy plus stent implantation (DCA + stent) in the treatment of isolated proximal left anterior descending coronary (LAD) lesions. One hundred and twenty-six patients underwent LIMA-LAD and 132 consecutive patients underwent DCA + stenting. The primary endpoint was the incidence of short- and long-term major adverse cardiac events (MACE); the secondary endpoints included any periprocedural events and long-term target vessel revascularization (TVR). We found no significant between-treatment difference in the occurrence of short-term MACE, and the long-term MACE rate per 100 person-years was 3.0 in the LIMA-LAD group and 4.6 in the DCA + stent group. After 5-year follow-up, 79% of the patients in the DCA + stent group and 89% of those in the LIMA-LAD group were still MACE-free. The risk of any periprocedural events was six times lower in the DCA + stent group, and the risk of TVR was six times higher. We conclude that both procedures lead to good short- and long-term follow-up results in isolated proximal LAD disease. As fewer periprocedural events and more TVRs occur after DCA + stenting than after LIMA-LAD, they can be considered valuable alternatives to each other.

Randomized comparison of debulking followed by stenting versus stenting alone for ostial left anterior descending artery stenosis: intravascular ultrasound guidance

BACKGROUND

Although directional coronary atherectomy (DCA) before stenting has the advantage of combining substantial removal of atheromatous plaque and prevention of elastic recoil, there has been no randomized study to investigate its efficacy in ostial left anterior descending artery (LAD) lesions. This study was aimed to evaluate the effect of DCA followed by stenting on ostial LAD stenosis under the guidance of intravascular ultrasound (IVUS).

METHODS

Eighty-six patients with ostial LAD stenoses were randomly assigned to DCA followed by stenting (group I) or stenting alone (group II). Aggressive DCA or optimal stenting was performed in both groups under the guidance of IVUS. The primary end point was angiographic restenosis at 6 months.

RESULTS

Baseline clinical and angiographic characteristics were similar between the 2 groups. The postprocedural minimal lumen diameter was larger in group I than group II (4.0 +/- 0.4 mm vs. 3.5 +/- 0.5 mm, P <.001). However, the angiographic restenosis rates were not significantly different between the 2 groups (9/32 [28.1%] in group I vs. 11/30 [36.7%] in group II, P =.472). The postprocedural IVUS stent area was the only independent determinant of restenosis by multivariate analysis (odds ratio.61, 95% CI 0.41-0.92, P =.018).

CONCLUSIONS

DCA followed by stenting achieved greater lumen gain than stenting alone for ostial LAD stenosis. However, DCA did not improve angiographic restenosis.

Stenting after directional coronary atherectomy compared with directional coronary atherectomy alone and stenting alone: a serial intravascular ultrasound study

BACKGROUND

Directional coronary atherectomy prior to stent implantation (DCA-stent) is expected to be an effective approach to reduce restenosis. The purpose of this study was to determine whether DCA-stent has advantages over DCA alone or stenting alone using serial intravascular ultrasound (IVUS).

METHODS AND RESULTS

Serial (pre-, post- and follow-up) IVUS was performed in 187 native coronary lesions treated with each of the 3 strategies. External elastic membrane cross-sectional area (CSA), lumen CSA and plaque CSA were measured. Baseline characteristics were similar. Postprocedural lumen CSA was largest after DCA-stent (11.2+/-2.7 mm2) and DCA (10.8+/-2.5 mm2) than stenting alone (9.0+/-2.9 mm2) (p<0.0005). Follow-up lumen loss was similar. As a result, follow-up lumen CSA was largest after DCA-stent (DCA-stent: 9.1+/-3.4 mm2, DCA: 7.8+/-4.2 mm2, stent: 6.3+/-2.6 mm2, p<0.0005). There was a trend toward a lower rate of restenosis with DCA-stent (DCA-stent, 12.5%; DCA, 18.3%; stent, 18.8%; p=0.57).

CONCLUSIONS

DCA-stent is superior to both DCA alone and stent alone in terms of the ability to gain a larger lumen as assessed by IVUS.

Early experience with a novel plaque excision system for the treatment of complex coronary lesions

The use of directional coronary atherectomy (DCA) in current practice has been limited. The SilverHawk System is a newly developed plaque excision device that aims to overcome the drawbacks of prior DCA platforms. The device was evaluated in a porcine coronary model and in a series of patients. Procedural variables along with outcomes were reviewed. Quantitative angiography (QCA) was performed and excised tissue fragments were weighed and examined histologically. In porcine cases, pretreatment MLD increased from 0.51 +/- 0.26 to 2.36 +/- 0.59 mm postdebulking and 19.9 +/- 7.6 mg of tissue was retrieved. In human cases, pretreatment MLD increased from 0.8 +/- 0.4 to 2.2 +/- 0.5 mm postdebulking and 15.2 +/- 7.8 mg of tissue was retrieved without complications. These data show that the SilverHawk System may offer significant utility in treating a wide variety of complex coronary lesions.