Remodeling of human coronary arteries undergoing coronary angioplasty or atherectomy

An Integrated Arterial Remodeling Hydrogel for Preventing Restenosis After Angioplasty

The high incidence of restenosis after angioplasty has been the leading reason for the recurrence of coronary heart disease, substantially increasing the mortality risk for patients. However, current anti-stenosis drug-eluting stents face challenges due to their limited functions and long-term safety concerns, significantly compromising their therapeutic effect. Herein, a stent-free anti-stenosis drug coating (denoted as Cur-NO-Gel) based on a peptide hydrogel is proposed. This hydrogel is formed by assembling a nitric oxide (NO) donor-peptide conjugate as a hydrogelator and encapsulating curcumin (Cur) during the assembly process. Cur-NO-Gel has the capability to release NO upon β-galactosidase stimulation and gradually release Cur through hydrogel hydrolysis. The in vitro experiments confirmed that Cur-NO-Gel protects vascular endothelial cells against oxidative stress injury, inhibits cellular activation of vascular smooth muscle cells, and suppresses adventitial fibroblasts. Moreover, periadventitial administration of Cur-NO-Gel in the angioplasty model demonstrate its ability to inhibit vascular stenosis by promoting reendothelialization, suppressing neointima hyperplasia, and preventing constrictive remodeling. Therefore, the study provides proof of concept for designing a new generation of clinical drugs in angioplasty.

Post-angioplasty remodeling of coronary arteries investigated via a chemo-mechano-biological in silico model

This work presents the application of a chemo-mechano-biological constitutive model of soft tissues for describing tissue inflammatory response to damage in collagen constituents. The material model is implemented into a nonlinear finite element formulation to follow up a coronary standard balloon angioplasty for one year. Numerical results, compared with available in vivo clinical data, show that the model reproduces the temporal dynamics of vessel remodeling associated with subintimal damage. Such dynamics are bimodular, being characterized by an early tissue resorption and lumen enlargement, followed by late tissue growth and vessel constriction. Applicability of the modeling framework in retrospective studies is demonstrated, and future extension towards prospective applications is discussed.

Serial quantitative angiographic study of target lumen enlargement after drug-coated balloon angioplasty for native coronary artery disease

BACKGROUND

Target lumen enlargement (TLE) or "late lumen enlargement" is often encountered after percutaneous coronary intervention (PCI) with drug-coated balloons (DCB). To date, the prognosis of coronary arterial lesions with or without TLE has not been clearly elucidated.

AIMS

This study aimed to assess the long-term prognosis of coronary arterial lesions with or without TLE observed within 1 year (early TLE) after DCB angioplasty using serial quantitative angiographic follow-up.

METHODS

One hundred and ninety-three consecutive patients (de novo coronary arterial lesions, 251) who underwent follow-up angiography within 1 year after DCB angioplasty (early follow-up, median: 6 months) were retrospectively evaluated. Of these, 97 patients (125 lesions) also underwent angiography more than 1 year after DCB angioplasty (late follow-up, median: 37 months). TLE was defined as an increase in minimal lumen diameter (MLD) after PCI at each follow-up.

RESULTS

Early TLE was detected in 142 lesions (56.6%). Of these, 76 lesions were also evaluated at late follow-up. TLE persisted even at late follow-up in 67 of the 76 lesions (88.2%). An increase in MLD in early TLE (+) lesions was observed in the period between post-PCI and early follow-up (1.84 ± 0.06 vs. 2.12 ± 0.07 mm, p < 0.001) but not between early and late follow-up (2.12 ± 0.07 vs. 2.16 ± 0.07 mm, p = 0.74). In contrast, 49 of 109 lesions without early TLE were evaluated at late follow-up, of which 28 lesions (57.1%) showed TLE at late follow-up. The MLD of early TLE (-) lesions (n = 49) significantly increased from early (1.63 ± 0.061 mm) to late follow-up (1.84 ± 0.06 mm) (p < 0.001). No aneurysms were found in any of these cases.

CONCLUSION

Early TLE was observed in more than half of the lesions, with the majority remaining at late follow-up. Alternatively, half of the lesions without early TLE showed late TLE, occurring biphasically after DCB angioplasty.

Development of a polycaprolactone/poly(p-dioxanone) bioresorbable stent with mechanically self-reinforced structure for congenital heart disease treatment

Recent progress in bioresorbable stents (BRSs) has provided a promising alternative for treating coronary artery disease. However, there is still lack of BRSs with satisfied compression and degradation performance for pediatric patients with congenital heart disease, leading to suboptimal therapy effects. Here, we developed a mechanically self-reinforced composite bioresorbable stent (cBRS) for congenital heart disease application. The cBRS consisted of poly(p-dioxanone) monofilaments and polycaprolactone/poly(p-dioxanone) core-shell composite yarns. Interlacing points in cBRS structure were partially bonded, offering the cBRS with significantly higher compression force compared to typical braids and remained good compliance. The suitable degradation profile of the cBRS can possibly preserve vascular remodeling and healing process. In addition, the controllable structural organization provides a method to customize the performance of the cBRS by altering the proportion of different components in the braids. The in vivo results suggested the cBRS supported the vessel wall similar to that of metallic stent. In both abdominal aorta and iliac artery of porcine, cBRS was entirely endothelialized within 1 month and maintained target vessels with good patency in the 12-month follow-up. The in vivo degradation profile of the cBRS is consistent with static degradation results in vitro. It is also demonstrated that there is minimal impact of pulsatile pressure of blood flow and variation of radial force on the degradation rate of the cBRS. Moreover, the lumen of cBRS implanted vessels were enlarged after 6 months, and significantly larger than the vessels implanted with metallic stent in 12 months.

Possible mechanism of late lumen enlargement after treatment for de novo coronary lesions with drug-coated balloon

BACKGROUND

Drug-coated balloon (DCB) treatment for de novo coronary artery disease has demonstrated late lumen enlargement (LLE) in mid-term follow-up and it was considered as clinical benefit; however, its mechanism and the predictive factor remains unclear.

METHODS

This study enrolled 46 consecutive patients (54 lesions) treated with DCB, using intravascular ultrasound (IVUS) at the index procedure and at the 9-month follow-up. We measured IVUS parameters at 1-mm intervals and calculated the mean volume of the external elastic membrane (EEM), lumen, and plaque. We calculated the dissection index (DI) defined as summation of the following points, 2: dissection over EEM, 1: intra-EEM dissection, 0: no dissection at every 1-mm interval, and divided by lesion length.

RESULTS

IVUS showed that there was no flow limiting dissection just after DCB treatment, the mean EEM and lumen volume (LV) had significantly increased while mean plaque volume had significantly decreased at 9 months, and 74.1% lesions exhibited LLE. We divided the patients into three groups according to delta mean LV. Mean EEM volume significantly increased and mean plaque volume significantly decreased in the larger and smaller LLE groups, but not in the non-LLE group. The DI was higher in a descending order in the three groups. The multiple regression analysis demonstrated that the DI was the strongest predictor of the change in mean LV.

CONCLUSIONS

LLE after DCB treatment may be caused by vessel enlargement and plaque regression. The non-flow limiting larger dissection just after DCB treatment may strongly associate with the intending LLE.

Two decades after coronary radiation therapy: A single center longitudinal clinical study

Objectives

The aim of this study was to evaluate the very long‐term clinical outcome after radioactive stent (RS) implantation and intracoronary β radiation brachytherapy (IRBT).

Background

Radioactive stents (RS) and intracoronary β radiation brachytherapy (IRBT) were introduced to prevent restenosis after percutaneous coronary intervention (PCI). Both techniques were associated with a higher incidence of major adverse cardiac events (MACE) in the short and intermediate‐term follow up as compared to conventional PCI.

Methods

One hundred and thirty‐three patients received radioactive stents (³²P) and 301 patients were treated with IRBT adjunctive to PCI. These groups were propensity matched to respectively 266 and 602 control patients who were treated with routine PCI during the same inclusion period. Endpoints were all‐cause mortality and MACE, defined as all‐cause death, any myocardial infarction or any revascularization.

Results

Median follow‐up duration was 17 years. All‐cause mortality rates were similar in all groups. Adjusted hazard ratios for MACE and mortality in the RS cohort were 1.55 (95% CI 1.20–2.00) and 0.92 (95% CI 0.63–1.34), respectively. Adjusted hazard ratios for MACE and all‐cause mortality in the IRBT cohort were 1.41 (95% CI 1.18–1.67) and 0.95 (95% CI 0.74–1.21), respectively. The difference in MACE rates was predominantly driven by coronary revascularizations in both groups, with a higher MI rate in the IRBT group as well.

Conclusions

Coronary radiation therapy was associated with early increased MACE rates, but the difference in MACE rates decreased beyond 2 years, resulting in a comparable long‐term clinical outcome. Importantly, no excess in mortality was observed.

Chronic stent recoil in severely calcified coronary artery lesions. A serial optical coherence tomography study

Chronic second-generation drug-eluting stent recoil in severely calcified coronary lesions has not been studied. We aimed to evaluate chronic stent recoil by optical coherence tomography (OCT) in severely calcified lesions treated with thin strut stents after rotational atherectomy. In 28 lesions (26 patients with 23% on hemodialysis) treated with everolimus-eluting stents after rotational atherectomy, baseline and 8-month follow-up OCT were compared. Stent recoil was defined as >10% decrease in stent area from baseline to follow-up. Overall, there was no change in minimal stent area (6.0 mm² [5.0, 8.1] to 6.0 mm² [4.8, 8.6], p = 0.51) from baseline to follow-up, although neointimal hyperplasia measured 16.3 ± 15.8%. Thirty-six percent of lesions showed stent recoil associated with 6 non-nodular calcifications, 1 calcified nodule, and 3 stent deformations. The overall mean calcium angle with attenuation decreased (54° [29-76] to 31° [19-48], p < 0.0001), and calcium without attenuation increased (28° [21-67] to 64° [34-93], p < 0.0001), but primarily at the location of stent recoil. Furthermore, in the stent recoil segments in 10 recoil lesions, the stent circumference decreased primarily at non-calcium segments rather than at calcium with or without attenuation. One lesion with stent recoil and 2 lesions without stent recoil required repeat revascularization. Thin strut stents can chronically recoil in severely calcified lesions, but this rarely causes restenosis.

Mechanism of Drug-Eluting Absorbable Metal Scaffold Restenosis

Background:

The pathomechanisms underlying restenosis of the bioabsorbable sirolimus-eluting metallic scaffold (Magmaris) remain unknown. Using serial optical coherence tomography, we investigated causes of restenosis, including the contribution of late scaffold recoil versus neointimal hyperplasia.

Methods:

Patients enrolled in BIOSOLVE-II undergoing serial angiography and optical coherence tomography (post-intervention and follow-up: 6 months and/or 1 year) were analyzed. Patients were divided into 2 groups according to angiographic in-scaffold late lumen loss (LLL) <0.5 or ≥0.5 mm. End points were late absolute scaffold recoil and neointimal hyperplasia area as assessed by optical coherence tomography.

Results:

Serial data were available for analysis from 70 patients (LLL <0.5 mm: n=41; LLL ≥0.5 mm: n=29). Patient and lesion characteristics were comparable, and there was no significant difference in mean and minimal scaffold area between groups at post-intervention. Late absolute scaffold recoil was less among patients with LLL <0.5 mm (0.53±0.68 mm 2 ) compared with those with LLL ≥0.5 mm (1.48±1.20 mm 2 ; P <0.001). Neointimal hyperplasia area was smaller among patients with LLL <0.5 mm at follow-up (1.47±0.33 mm 2 ) compared with patients with LLL ≥0.5 mm (1.68±0.34 mm 2 ; P =0.013). In a matched-frame analysis (post-intervention and follow-up), late absolute scaffold recoil varied according to the underlying plaque type (lipid: 0.63±1.23 mm 2 ; calcified: 0.81±1.44 mm 2 ; and fibrous: 1.20±1.52 mm 2 ; P <0.001), while there was no difference with regards to neointimal hyperplasia area ( P =0.132).

Conclusions:

In addition to neointimal hyperplasia, late scaffold recoil contributed significantly to LLL of sirolimus-eluting absorbable metal scaffolds. The extent of late scaffold recoil was dependent on the underlying plaque morphology and was the highest among fibrotic lesions.

Registration:

URL: https://www.clinicaltrials.gov . Unique identifier: NCT01960504.

Long-Term Evolutionary Change in the Lumen of Intracranial Atherosclerotic Stenosis Following Angioplasty and Stenting

BACKGROUND

Angioplasty and stenting is a recognized treatment option for patients with intracranial atherosclerosis.

OBJECTIVE

To evaluate the long-term evolutionary luminal changes of intracranial atherosclerosis after angioplasty and stenting.

METHODS

This was a retrospective study with patient consent. Eighty-two patients presenting with acute and minor cerebral ischemia due to stenosis ≥70%, who had received medical therapy with or without stenting (Wingspan), were invited. Luminal imaging was provided using 3-dimensional rotational angiography (3-DRA) at baseline and 12 mo, and cone-beam computed tomography angiography with intravenous contrast (CBCT) was provided at follow-up (median 82.4 mo [interquartile range 61.9-96.9 mo]).

RESULTS

Thirty-six patients in the stenting group and 26 patients in the medical group were recruited and completed the study. There was no statistically significant difference in demographics between the 2 patient groups. The luminal gain at 12 or 80 mo as compared to baseline in the stenting group was significantly greater than that in the medical group (12 mo: median gain 30% vs 7.2%, P < .001; 80 mo: median gain 42.9% vs 7.2%, P < .0001). Luminal loss or unchanged lumen was correlated with recurrent ischemic event. The differences in the stenosis degree assessment between CBCT and 3-DRA in the same 10 patients with or without stenting were 1.2 ± 0.6% or 0.2 ± 0.06%, respectively. There was a correlation between recurrent ischemic events and luminal loss.

CONCLUSION

Arterial lumen after angioplasty and stenting can probably be well maintained and delayed luminal gain does occur, long-term luminal loss is associated with recurrent ischemic events, CBCT might be useful as a less-invasive means for long-term assessment.

Serial invasive imaging follow-up of the first clinical experience with the Magmaris magnesium bioresorbable scaffold

Objectives

To assess the performance of the commercially available Magmaris sirolimus‐eluting bioresorbable scaffold (BRS) with invasive imaging at different time points.

Background

Coronary BRS with a magnesium backbone have been recently studied as an alternative to polymeric scaffolds, providing enhanced vessel support and a faster resorption rate. We aimed to assess the performance of the commercially available Magmaris sirolimus‐eluting BRS at different time points.

Methods

A prospective, single‐center, nonrandomized study was performed at the Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands. Six patients with stable de novo coronary artery lesions underwent single‐vessel revascularization with the Magmaris sirolimus‐eluting BRS. Invasive follow‐up including intravascular imaging using optical coherence tomography (OCT) was performed at different time points.

Results

At a median of 8 months (range 4–12 months) target lesion failure occurred in one patient. Angiography revealed a late lumen loss of 0.59 ± 0.39 mm, a percentage diameter stenosis of 39.65 ± 15.81%, and a binary restenosis rate of 33.3%. OCT showed a significant reduction in both minimal lumen area (MLA) and scaffold area at the site of the MLA by 43.44 ± 28.62 and 38.20 ± 25.74%, respectively. A fast and heterogeneous scaffold degradation process was found with a significant reduction of patent struts at 4–5 months.

Conclusions

Our findings show that the latest iteration of magnesium BRS suffers from premature dismantling, resulting in a higher than expected decrease in MLA.

Serial Optical Coherence Tomography at Baseline, 7 Days, and 1, 3, 6 and 12 Months After Bioresorbable Scaffold Implantation in a Growing Porcine Model

BACKGROUND

Little is known about serial changes in lumen and device dimensions after bioresorbable scaffold implantation in a growing animal model. Methods and Results: ABSORB (n=14) or bare metal stents (ICROS amg [Abbott Vascular, Santa Clara, CA, USA], Winsen-Luhe, Germany; n=15) were implanted in the coronary arteries of domestic swine (a hybrid of Finnish-Norwegian Landrace swine) weighing 30-35 kg. Angiography and optical coherence tomography (OCT) were performed immediately after implantation and repeated at 7 days, 1, 3, 6 and 12 months after the index procedure. One month after implantation, mean lumen area decreased relative to baseline in both groups (relative area change from baseline, -41.4±15.6% for ABSORB vs. -20.9±18.6% for ICROS) while mean device area decreased only in the ABSORB group (relative area change: -11.1±9.4% vs. +0.14±7.95%, respectively). At 12 months, mean lumen area increased relative to baseline in both groups (relative area change from baseline, +55.6±22.4% vs. +32.3±83.6%, respectively) in accordance with the swine growth weighing up to 260-300 kg. Mean device area in the ICROS group remained stable whereas that in the ABSORB group began to increase between 3 and 6 months along with the vessel growth (relative area change: +107.8±25.7% vs. +0.14±7.95%).

CONCLUSIONS

In the growing porcine model, ABSORB was associated with greater extent of recoil 1 month after implantation compared with ICROS but demonstrated substantial adaptability to vessel growth in late phase.

Optimization of balloon coating process for paclitaxel coated balloons via micro-pipetting method

Drug coated balloons (DCBs) have proven to be a suitable alternative for the treatment of cardiovascular diseases. They allow for uniform delivery of an antiproliferative drug to the stenotic site without permanent implantation of the device in the patient's body. There are, however, regulatory concerns regarding the lack of data associated with variable drug delivery to the target site, which can be related to the coating process. This study describes the process for an in-house micro-pipetting coating method that incorporates a laboratory-developed coating equation for determining optimal coating parameters. The coating solutions included a common drug of choice, paclitaxel, along with a hydrophilic excipient, such as iopromide. It was found that using a revolution rate of 240 rev/min, a flow rate of 25 µL/min and a translational speed of 0.033 cm/s resulted in visually uniform coatings. High performance liquid chromatography (HPLC) allowed for the determination of paclitaxel content on the balloon surface. Scanning electron microscopy (SEM) enabled analysis of coating thickness and texture at distal, middle, and proximal positions on the balloon; average thicknesses were determined to be 16.4 ± 5.8, 14.8 ± 1.4, and 18.1 ± 3.9 µm, respectively. These optimized coating conditions have been confirmed by in vitro drug release kinetics studies. Overall this study generated a simple and reproducible micro-pipetting coating method for the sustained release of drugs from the drug coated balloons.

Arterial Remodeling After Bioresorbable Scaffolds and Metallic Stents

BACKGROUND

Although previous observational studies have documented late luminal enlargement and expansive remodeling following implantation of a bioresorbable vascular scaffold (BVS), no comparison with metallic stents has been conducted in a randomized fashion.

OBJECTIVES

This study sought to compare vessel remodeling patterns after either Absorb BVS or Xience metallic drug-eluting stent (DES) implantation (Abbott Vascular, Santa Clara, California) and determine the independent predictors of remodeling.

METHODS

In the ABSORB II randomized trial, 383 lesions (n = 359) were investigated by intravenous ultrasound both post-procedure and at 3-year follow-up. According to vessel and lumen area changes over 3 years, we categorized 9 patterns of vessel remodeling that were beyond the reproducibility of lumen and vessel area measurements.

RESULTS

The relative change in mean vessel area was significantly greater with the BVS compared to the DES (6.7 ± 12.6% vs. 2.9 ± 11.5%; p = 0.003); the relative change in mean lumen area was significantly different between the 2 arms (1.4 ± 19.1% vs. -1.9 ± 10.5%, respectively; p = 0.031). Multivariate analysis indicated that use of the BVS, female sex, balloon-artery ratio >1.25, expansion index ≥0.8, previous percutaneous coronary intervention, and higher level of low-density lipoprotein cholesterol were independent predictors of expansive remodeling. Furthermore, in the BVS arm, necrotic core pre-procedure was an independent determinant of expansive remodeling.

CONCLUSIONS

Expansive vessel wall remodeling was more frequent and intense with the BVS than the metallic DES and could be determined by patient baseline characteristics and periprocedural factors. The clinical effect of the observed lumen and vessel remodeling must be investigated in further large clinical studies to optimize the clinical outcome of patients and lesions treated by bioresorbable scaffolds. (ABSORB II Randomized Controlled Trial; NCT01425281).

A new approach to improve the local compressive properties of PPDO self-expandable stent

The radial performance of bioabsorbable polymeric intravascular stents is extremely important in assessing the efficiency of these devices in expanding narrow lumen, reducing stent recoil, and recovering to their original states after suffering from pulsating pressure. However, these stents remain inferior to metallic stents. Several thermal treatment conditions (60°C, 80°C, and 100°C for 1h) were investigated to improve the characteristics of poly(p-dioxanone) (PPDO) self-expandable stents. The local compressive force, stiffness, and viscoelasticity of these stents were also evaluated. Wide-angle X-ray diffraction and different scanning calorimetry measurements were performed to evaluate the recrystalline and thermodynamic changes of molecular chains. The declining conformer entropy of PPDO monofilaments was examined via energy analysis. The untreated stents had compressive modules of 514.80±70.59mN/mm, which was much higher than those of 80°C and 100°C treated stents (332.35±66.08mN/mm and 394.31±64.71mN/mm, respectively). Nevertheless, 100°C annealing stents had less stress relaxation and prior elastic recovery rate of 82.32±3.43mN and 92.55±1.61%, respectively, showing a much better shape stability than untreated stents (139.51±16.67mN and 86.18±3.57%, respectively). These findings present important clinical implications in the stent manufacturing process and warrant further study to develop new bioabsorbable stents with outstanding clinical efficacy.

Bioresorbable scaffold - A magic bullet for the treatment of coronary artery disease?

Today, drug-eluting metal stents are considered the gold standard for interventional treatment of coronary artery disease. While providing inhibition of neointimal hyperplasia, drug-eluting metal stents have many limitations such as the risk of late and very late stent thrombosis, restriction of vascular vasomotion and chronic local inflammatory reaction due to permanent implantation of a 'metallic cage', recognized as a foreign body. Bioresorbable scaffold stents (BRS) are a new solution, which is trying to overcome the limitation of the 'metallic cage'. This structure provides short-term scaffolding of the vessel and then disappears, leaving nothing behind. The purpose of this review is to present the theoretical rationale for the use of BRS and to outline the clinical outcomes associated with their use in terms of data obtained from RCTs, clinical trials, registries and real life use. We have also tried to answer all questions on this intervention based on available data, with a focus on ABSORB BVS (Abbott Vascular, Santa Clara, USA). We consider that this new technology can be the "magic bullet" to treat coronary artery disease.

Short-term outcomes in patients with acute coronary syndrome treated with direct bioresorbable scaffold deployment

BACKGROUND

Direct coronary stenting is a validated therapeutic option for coronary lesions. We studied the feasibility of direct deployment with a bioresorbable vascular scaffold (BVS) in acute coronary syndrome (ACS).

METHODS

Demographic, procedural, and survival data were obtained for patients who had direct scaffold deployment with BVS from 1 May 2013 to 1 April 2014.

RESULTS

We performed a retrospective review of nine patients which included eight patients having ST-elevation myocardial infarction. There were no cases of worsening coronary flow, scaffold thrombosis, target lesion revascularization or death up to 30 days post intervention.

CONCLUSION

Direct BVS deployment in ACS appears safe and feasible.

The vulnerable coronary plaque: update on imaging technologies

Several studies have been carried out on vulnerable plaque as the main culprit for ischaemic cardiac events. Historically, the most important diagnostic technique for studying coronary atherosclerotic disease was to determine the residual luminal diameter by angiographic measurement of the stenosis. However, it has become clear that vulnerable plaque rupture as well as thrombosis, rather than stenosis, triggers most acute ischaemic events and that the quantification of risk based merely on severity of the arterial stenosis is not sufficient. In the last decades, substantial progresses have been made on optimisation of techniques detecting the arterial wall morphology, plaque composition and inflammation. To date, the use of a single technique is not recommended to precisely identify the progression of the atherosclerotic process in human beings. In contrast, the integration of data that can be derived from multiple methods might improve our knowledge about plaque destabilisation. The aim of this narrative review is to update evidence on the accuracy of the currently available non-invasive and invasive imaging techniques in identifying components and morphologic characteristics associated with coronary plaque vulnerability.

Impact of statin therapy on late target lesion revascularization after sirolimus-eluting stent implantation (from the CREDO-Kyoto Registry Cohort-2)

Therapeutic strategies preventing late target lesion revascularization (TLR) after drug-eluting stent implantation have not been yet adequately investigated. In 13,087 consecutive patients undergoing first percutaneous coronary intervention in the CREDO-Kyoto Registry Cohort-2, we identified 10,221 patients who were discharged alive after implantation of sirolimus-eluting stents (SESs) only (SES stratum 5,029) or bare-metal stents (BMSs) only (BMS stratum 5,192). Impact of statin therapy at time of discharge from the index hospitalization on early (within the first year) and late (1 year to 4 years) TLR, was assessed in the SES stratum (statin group 2,735; nonstatin group 2,294) and in the BMS stratum (statin group 2,576; nonstatin group 2,616). Despite a significantly lower incidence of early TLR (7.8% vs 22.2%, p <0.0001), SES use compared to BMS use was associated with a significantly higher incidence of late TLR (7.7% vs 3.0%, p <0.0001). In the SES and BMS strata, the incidence of early TLR was similar regardless of statin use. In the SES stratum, the incidence of late TLR was significantly lower in the statin group than in the nonstatin group (6.1% vs 9.6%, p = 0.002), whereas no significant difference was found in the BMS stratum (2.6% vs 3.3%, p = 0.38). After adjusting confounders, risk for late TLR significantly favored statin use in the SES stratum (hazard ratio 0.73, 95% confidence interval 0.54 to 0.98, p = 0.04), whereas the risk decrease was not significant in the BMS stratum (hazard ratio 0.74, 95% confidence interval 0.46 to 1.20, p = 0.23). In conclusion, statin therapy at hospital discharge was associated with a significantly lower risk for late TLR after SES implantation.

Everolimus-eluting ABSORB bioresorbable vascular scaffold: present and future perspectives

Everolimus-eluting ABSORB bioresorbable vascular scaffolds represent a novel approach that provides transient vessel support with drug-delivery capability without the long-term limitations of the metallic drug-eluting stents (DESs). The technology has the potential to overcome many of the safety concerns associated with metallic DESs and possibly even convey further clinical benefit. In particular the scaffold is designed for providing a short-term lumen support (up to 6-12 months) and for thereafter being completely bioresorbed, eliminating the permanent caging typical of the metallic DES. The first clinical studies testing this device in a small number of patients have shown very promising results with good clinical outcome up to 5 years' follow-up, highlighting important morphological and functional modifications at the scaffolded segment level, such as late lumen enlargement and recuperation of a normal vasoreactivity. A randomized trial, comparing ABSORB with the Xience Prime stent, will evaluate the efficacy and safety of this device in a wide population.

Positive remodeling is associated with vulnerable coronary plaque components regardless of clinical presentation: virtual histology-intravascular ultrasound analysis

OBJECTIVE

We used virtual histology-intravascular ultrasound (VH-IVUS) to evaluate the relation between coronary artery remodeling pattern and plaque components in 1133 patients.

METHODS

We divided the patients into two groups according to the remodeling pattern as positive remodeling (PR, remodeling index>1.05) (n=192) and intermediate remodeling (IR, remodeling index ≤ 1.05 and ≥ 0.95)/negative remodeling (NR, remodeling index<0.95) (n=941). VH-IVUS analysis classified the color-coded tissue into four major components: green (fibrotic, FT); yellow-green (fibro-fatty); white (dense calcium); and red (necrotic core, NC). Thin-cap fibroatheroma (TCFA) was defined as focal, NC-rich (≥ 10% of the cross-sectional area) plaques being in contact with the lumen in a plaque burden ≥ 40%.

RESULTS

At the minimum lumen site, PR group had greater plaque plus media area (12.8 ± 4.9 vs. 9.9 ± 3.8mm(2), p<0.001) and greater %NC area (21.7 ± 12.3 vs. 18.2 ± 11.6%, p<0.001) and smaller %FT area (57.0 ± 14.5 vs. 59.4 ± 14.6%, p=0.037) compared with IR/NR group. PR group had greater plaque volume (188 ± 150 vs. 135 ± 130 mm(3), p<0.001) and greater %NC volume (19.1 ± 9.6 vs. 16.6 ± 9.2%, p=0.001) and smaller %FT volume (58.3 ± 11.7 vs. 60.6 ± 11.0%, p=0.009) compared with IR/NR group. PR group had more TCFA compared with IR/NR group (21% vs. 13%, p=0.006). Similar findings about plaque components were observed in terms of greater %NC volume and smaller %FT volume in PR group compared with IR/NR group in patients with both acute coronary syndrome and stable angina.

CONCLUSIONS

VH-IVUS analysis demonstrates that PR was associated with more vulnerable plaque components compared with IR/NR regardless of their clinical presentation.

Disease progression in nonintervened saphenous vein graft segments a serial intravascular ultrasound analysis

OBJECTIVES

We used serial intravascular ultrasound (IVUS) to assess disease progression in nonintervened saphenous vein graft (SVG) segments to determine the natural rate of disease progression in SVG.

BACKGROUND

There are no serial IVUS studies of disease progression or luminal compromise in SVGs.

METHODS

We assessed serial (baseline and follow-up at 16.2 +/- 7.4 months) IVUS findings in 50 nonintervened SVG segments in 44 patients. The SVG age was 13.5 +/- 3.6 years.

RESULTS

Overall, from baseline to follow-up, plaque area increased (Delta = +0.58 +/- 1.25 mm(2), p = 0.003), and SVG and minimum lumen area (MLA) decreased (Delta = -0.50 +/- 1.14 mm(2), p = 0.002, and Delta = -1.08 +/- 1.28 mm(2), p < 0.001, respectively). The MLA decreased in 34 lesions (Delta = -1.67 +/- 1.08 mm(2)), and MLA increased in 16 lesions (Delta = +0.19 +/- 0.47 mm(2)). Compared with lesions with an increase in MLA, lesions with a decrease in MLA were associated with: 1) larger baseline SVG and plaque areas and plaque burden (15.57 +/- 3.90 mm(2) vs. 11.55 +/- 2.30 mm(2), p < 0.001; 7.97 +/- 3.77 mm(2) vs. 4.27 +/- 1.92 mm(2), p < 0.001; and 48.7 +/- 14.2% vs. 36.0 +/- 13.4%, p = 0.004, respectively); and 2) a greater decrease in SVG area (Delta = -0.96 +/- 1.05 mm(2) vs. +0.48 +/- 0.58 mm(2), p < 0.001) and greater increase in plaque area (Delta = +0.71 +/- 1.47 mm(2) vs. +0.29 +/- 0.45 mm(2), p < 0.001). The DeltaMLA correlated with both Deltaplaque area (r = -0.589, p < 0.001) and DeltaSVG area (r = 0.470, p = 0.001), and Deltaplaque area correlated with DeltaSVG area (r = 0.436, p = 0.002). There were linear relations between both the Deltaplaque area (r = 0.519, p < 0.001) and Deltalumen area (r = -0.500, p < 0.001) versus follow-up low-density lipoprotein (LDL) cholesterol; a follow-up LDL cholesterol of 100 mg/dl predicted no plaque increase.

CONCLUSIONS

Lumen loss in nonintervened SVG segments correlated with an increase in plaque area and a decrease in SVG area (plaque growth and negative remodeling) with a linear relationship between plaque growth versus follow-up LDL cholesterol leading to long-term lumen loss.

Regulation of arterial remodeling and angiogenesis by urokinase-type plasminogen activatorThis article is one of a selection of papers from the NATO Advanced Research Workshop on Translational Knowledge for Heart Health (published in part 2 of a 2-part Special Issue)

A wide variety of disorders are associated with an imbalance in the plasminogen activator system, including inflammatory diseases, atherosclerosis, intimal hyperplasia, the response mechanism to vascular injury, and restenosis. Urokinase-type plasminogen activator (uPA) is a multifunctional protein that in addition to its fibrinolytic and matrix degradation capabilities also affects growth factor bioavailability, cytokine modulation, receptor shedding, cell migration and proliferation, phenotypic modulation, protein expression, and cascade activation of proteases, inhibitors, receptors, and modulators. uPA is the crucial protein for neointimal growth and vascular remodeling. Moreover, it was recently shown to be implicated in the stimulation of angiogenesis, which makes it a promising multipurpose therapeutic target. This review is focused on the mechanisms by which uPA can regulate arterial remodeling, angiogenesis, and cell migration and proliferation after arterial injury and the means by which it modulates gene expression in vascular cells. The role of domain specificity of urokinase in these processes is also discussed.

Intravascular ultrasound predictors of major adverse cardiac events in patients with unstable angina

BACKGROUND

Intravascular ultrasound (IVUS) predictors of native culprit lesion morphology for occurrence of major adverse cardiac events (MACE) have not been reported. Moreover, the published data on IVUS predictors of restenosis include patients with stable and unstable angina, although the development and progression of atherosclerosis related to unstable coronary syndrome is different from that of stable angina.

HYPOTHESIS

This study investigated whether IVUS-derived qualitative and quantitative parameters of native (preangioplastic) plaque morphologic features can predict major adverse cardiac events in patients with unstable angina.

METHODS

Clinical (age, gender, coronary risk factors), qualitative and quantitative angiographic (lesion localization, morphology, pre- and postangioplastic minimal lumen diameter, reference diameter, and percent diameter stenosis), and IVUS variables (soft/fibrocalcific plaque, calcification, presence of thrombus or plaque disruption, different types of arterial remodeling, pre- or postangioplastic minimal lumen, external elastic membrane and plaque cross-sectional area, and plaque burden of the target lesion and reference segments) were analyzed by regression analyses using the Cox model, assuming proportional hazards.

RESULTS

Of 60 consecutively enrolled patients, 21 suffered from MACE, while 39 remained event-free during the followup period. Multivariate regression analyses revealed that the presence of adaptive remodeling [p = 0.0177, risk ratio (RR) = 3.108, with 95% confidence interval (CI) = 1.371-8.289] and the preangioplastic lumen cross-sectional area (p = 0.0130, RR = 0.869, with 95% CI = 0.667-0.913) are independent predictors of MACE during follow-up, as is postangioplastic angiographic minimal lumen diameter (p = 0.0330, RR = 0.715 with 95% CI = 0.678-0.812).

CONCLUSIONS

Adaptive remodeling and preangioplastic lumen cross-sectional area determined by IVUS and postangioplastic minimal lumen diameter calculated by quantitative angiography are significant independent predictors of time-dependent MACE in patients with unstable angina.

In vitro and in vivo analysis of expression cassettes designed for vascular gene transfer

Increasing the level and duration of transgene expression and restricting expression to vascular cells are important goals for clinically useful gene therapy vectors. We evaluated several promoters, enhancers and introns in endothelial, smooth muscle and liver cells in tissue culture and in vivo, comparing local delivery to the carotid artery with intravenous delivery to the liver. A 1800-bp fragment of the oxidized LDL receptor (LOX-1) promoter showed highest in vivo activity in the carotid artery, achieving 39% the activity of the reference cytomegalovirus promoter, with 188-fold greater specificity for carotid artery over liver. An enhancer from the Tie2 gene in combination with the intracellular adhesion molecule-2 promoter improved endothelial specificity of plasmid vectors, increased the expression from adenoviral vectors in cultured endothelial cells and doubled the specificity for carotid artery over liver in vivo. Adding a short intron to expression cassettes increased expression in both endothelial and smooth muscle cells in vitro; however, the eNOS enhancer failed to consistently increase the expression or endothelial specificity of the vector. In conclusion, elements from the LOX-1 promoter and Tie2 enhancer together with an intron can be used to improve vectors for vascular gene transfer.

Effects of percutaneous transluminal angioplasty and endovascular brachytherapy on vascular remodeling of human femoropopliteal artery: 2 years follow-up by noninvasive magnetic resonance imaging

OBJECTIVES

We aimed to assess in vivo the long-term effects of percutaneous transluminal angioplasty (PTA) and endovascular brachytherapy (EVBT) on vessel wall by serial MRI.

METHODS

Twenty patients with symptomatic stenosis of the femoropopliteal artery were randomly assigned to PTA (n=10) or PTA+EVBT (n=10, 14Gy by gamma-source). High-resolution MRI was performed prior, at 24-hours, 3-months, and 24-months after intervention. MRI data were analyzed by an independent, blinded observer.

RESULTS

The effects of both procedures on vessel wall at 24-hours and 3-months have been reported. Despite similar percent decrease in lumen area between 3- and 24-months in both groups (-8% for PTA and -11% for PTA+EVBT), at 24-months lumen area gain compared to baseline was +30% in PTA versus +82% in PTA+EVBT (p<0.05). Total vessel area, which was increased at 24-hours and 3-months, returned to pre-treatment value in both groups.

CONCLUSIONS

We demonstrated non-invasively that restenosis and inward remodeling after PTA are delayed by EVBT. At 24-months, patients treated with brachytherapy have larger lumen than those treated with PTA alone. The decrease in luminal and total vessel area between 3- and 24-months after EVBT indicates that the restenotic and remodeling process is not abolished but delayed with this therapy.

Preprocedure hyperglycemia is more strongly associated with restenosis in diabetic patients after percutaneous coronary intervention than is hemoglobin A1C

BACKGROUND

Although more frequent in diabetic patients, restenosis after percutaneous coronary intervention (PCI) is less common in those with good glycemic control. High circulating insulin levels may also be associated with more frequent restenosis.

METHODS

Fasting blood samples were obtained from 162 diabetic patients immediately prior to the PCI and analyzed for glucose, hemoglobin A1C, and insulin. Nine-month follow-up information was obtained in 145 (89.5%) patients. Target vessel revascularization (TVR) was the surrogate for restenosis.

RESULTS

Patients were divided into quartiles with regard to their blood levels. Insulin, calculated insulin resistance, and hemoglobin A1C were not associated with increased TVR rates. Glucose level was significantly associated (P=.02). Patients in the two lower quartiles (glucose < or = 128 mg/dl) had a 9-month TVR rate of 12.7% while those in the two higher quartiles (>128 mg/dl) had a rate of 33.8% (P=.005). Level of glucose was independent of hemoglobin A1C. In patients whose A1C level was < or = 7%, the TVR rate was greater in those with a glucose level >128 mg/dl (39.1% vs. 10.6%, P=.009). Similarly, in patients with a hemoglobin A1C level >7%, the TVR rate was lower in patients with a glucose level < or = 128 mg/dl, but this difference did not reach statistical significance (16.6% vs. 31.3%, P=.3).

CONCLUSIONS

Hemoglobin A1C, insulin, and insulin resistance at the time of the PCI are not associated with restenosis. Periprocedural hyperglycemia may promote restenosis in diabetics.

alpha8beta1 Integrin is up-regulated in the neointima concomitant with late luminal loss after balloon injury

INTRODUCTION

Constrictive remodeling of the neointima results in the late lumen loss and restenosis after balloon angioplasty. Intense expression of alpha8beta1 integrin in the contractile state of vascular smooth muscle cells (VSMCs) and in myofibroblasts led us to hypothesize that it might be involved in the process of late constrictive remodeling.

METHODS AND RESULTS

Balloon injury was used to induce neointima formation in the rat carotid artery. Immunohistochemical analysis and immunoconfocal studies showed that late lumen narrowing was concomitant with the up-regulation of smooth muscle alpha-actin and alpha8 integrin in the neointima. The transforming growth factor-beta (TGF-beta)-induced contractile properties of fibroblasts and VSMCs populated in a three-dimensional collagen matrix was associated with up-regulation of alpha8 integrin. TGF-beta-induced myofibroblastic features in Rat1 fibroblasts were impaired in cells pretreated with a small interference RNA silencing the alpha8 integrin gene.

CONCLUSION

The close correlation between alpha8 integrin up-regulation in the neointima and late luminal loss and alpha8 integrin being required for contractile properties induced by TGF-beta highlight a possible role for alpha8 integrin in postangioplasty restenosis.

Intravascular ultrasound for intracranial angioplasty and stent placement: technical case report

OBJECTIVE

Intravascular ultrasound (IVUS) imaging has been used extensively in coronary artery interventions and has provided invaluable information for the understanding and treatment of coronary arterial disease. We present here the first description, to our knowledge, of IVUS-guided intracranial arterial interventions in the clinical setting.

CLINICAL PRESENTATION

Two patients underwent intracranial angioplasty and stent placement with the assistance of IVUS for the evaluation of their lesions. One patient underwent stenting to treat an occlusive dissection of the left internal carotid artery that occurred during arteriovenous malformation embolization. Another patient underwent angioplasty and stenting for high-grade restenosis of a basilar artery atherosclerotic lesion.

RESULTS

Both patients underwent successful revascularization procedures. The patient with the dissection had a small intraventricular and parenchymal hemorrhage documented by computed tomography 4 hours after treatment, but did not develop hydrocephalus or further hemorrhage. Both patients did well clinically and had no permanent neurological deficits. IVUS provided important information in terms of lesion evaluation, stent selection, and stent placement in each case.

CONCLUSION

IVUS of the intracranial circulation may assist the performance of intracranial angioplasty and stenting. It provides useful information that can affect clinical decisions. It may prove to be a valuable tool in clinical use and enhance our understanding of vascular disease of the intracranial circulation, as it has in the coronary circulation.

Modified Paclitaxel-loaded Nanoparticles for Inhibition of Hyperplasia in a Rabbit Arterial Balloon Injury Model

PURPOSE

This study tested the possibility of localized intravascular infusion of positive charged paclitaxel-loaded nanoparticles (NPs) to better prevent neointimal formation in a rabbit carotid artery injury model.

MATERIALS AND METHODS

NPs were prepared by oil-water emulsion/solvent evaporation technique using biodegradable poly (lactide-co-glycolide) (PLGA). A cationic surfactant, didodecyldimethylammonium bromide (DMAB), was absorbed on the NP surface by electrostatic attraction between positive and negative charges. NPs were characterized in such aspects as size, surface morphology, surface charges as well as in vitro drug release profile. Balloon injured rabbit carotid arteries were treated with single infusion of paclitaxel-loaded NP suspension and observed for 28 days. The inhibitory effects of NPs on neointima formation were evaluated as end-point.

RESULTS

NPs showed spherical shape with a diameter ranging from 200 to 500 nm. Negatively charged PLGA NPs shifted to positive after the DMAB modification. The in vitro drug release profile showed a biphasic release pattern. Morphometric analyses on the retrieved artery samples revealed that the inhibitory effect of intima proliferation was dose-dependent. At a concentration of 30 mg ml(-1), NP infusion completely inhibited intima proliferation in a rabbit vascular injury model.

CONCLUSIONS

Paclitaxel-loaded NPs with DMAB modification were proven an effective means of inhibiting proliferative response to vascular injury in a rabbit model.

Oxidized low-density lipoprotein and high-density lipoprotein cholesterol modulate coronary arterial remodeling: an intravascular ultrasound study

BACKGROUND

Oxidized low-density lipoprotein (oxLDL) not only plays an important role in plaque formation, but also impairs the endothelium-dependent relaxation. Constrictive remodeling rather than intimal hyperplasia mainly contributes to restenosis after balloon angioplasty. Probucol (powerful antioxidant) reduced restenosis rate by improving constrictive remodeling. Thus, oxLDL may modulate coronary arterial remodeling.

HYPOTHESIS

The study was designed for using intravascular ultrasound to test the hypothesis that arterial constrictive remodeling (CR) was associated with oxLDL in patients with coronary artery disease.

METHODS

Intravascular ultrasound was performed in 36 patients with de novo atherosclerotic coronary. Remodeling was defined and evaluated as follows: remodeling index (RI) = lesion vessel area (VA)/(proximal reference VA + distal reference VA)/2. Constrictive remodeling (CR) was defined as remodeling index (RI) < 0.9. Neutral and expansive remodeling (NER) was defined as RI > or = 0.9. The level of plasma ox-LDL was measured by sandwich ELISA using the monoclonal antibody (DLH3)-recognized oxidatively modified lipoproteins and the antihuman apoprotein B monoclonal antibody.

RESULTS

Neutral and expansive remodeling was found in 24 lesions, and CR in 12 lesions. Remodeling index was significantly lower in the CR group than in the NER group (0.8 +/- 0.1 vs. 1.0 +/- 0.1, p < 0.001). The level of oxLDL in the CR group was significantly higher than that in the NER group (24.0 +/- 12.1 vs. 16.4 +/- 6.2 U/ml, p < 0.05). The level of high-density lipoprotein-cholesterol (HDL-C) in the CR group was significantly lower than that in the NER group (40.5 +/- 4.8 vs. 46.2 +/- 10.6 mg/ml, p < 0.05). There was a statistically significant correlation between the value of HDL-C/ ox-LDL and the RI (r = -0.48, p < 0.005).

CONCLUSIONS

Oxidized LDL and HDL-C were associated with arterial remodeling in de novo atherosclerotic lesions.

Percutaneous coronary revascularization in diabetics: from balloon angioplasty to drug-eluting stents

Diabetic patients may have aggressive coronary disease with an excessive rate of restenosis and accelerated atherosclerotic progression. This article reviews the different modalities of percutaneous treatment and their results in the diabetic population, from the early days of balloon angioplasty to the current implementation of drug-eluting stents. As restenosis may be virtually eradicated in the near future, plaque progression remains the cornerstone for interventional cardiologists and the medical community. In this regard, attempts to modify life habits, and a more accurate control of the components of the metabolic syndrome should be the main therapeutic objective.

Impact of different definitions on the interpretation of coronary remodeling determined by intravascular ultrasound

The objective of this study was to compare the categorizations and determinants related to remodeling by the three definitions commonly used. Several morphological and intravascular ultrasound (IVUS) studies have demonstrated the fundamental importance of arterial remodeling in atherosclerosis. However, lack of consensus on how to define remodeling has led to conflicting analyses of factors that influence this process. Analysis of pre-interventional IVUS images of 514 lesions in native coronary arteries was performed. Arterial remodeling was defined as outward by definition 1, when [cross-sectional area (CSA) of the external elastic membrane (EEM) at the lesion site (EEM(lesion))]/[EEM CSA either at the proximal (EEM(prox ref)) or distal (EEM(distal ref)) reference site with the least amount of plaque] was > 1.05, intermediate when this ratio was between 0.95 and 1.05, and inward when < 0.95. Remodeling was defined as outward by definition 2 when EEM(lesion) > both EEM(prox ref) and EEM(distal ref), inward when EEM(lesion) < both EEM(prox ref) and EEM(distal ref), and intermediate when EEM(lesion) was intermediate between EEM(prox ref) and EEM(distal ref). By definition 3, vessel remodeling was defined as outward when EEM(lesion) > (EEM(prox ref) + EEM(distal ref))/2 and intermediate/inward when EEM(lesion) < or = (EEM(prox ref) + EEM(distal ref))/2. The frequency of outward remodeling was significantly higher by definitions 1 and 3 than by definition 2, whereas a higher frequency of inward remodeling was observed in definition 1, resulting in significantly different remodeling distributions between the three definitions (P < 0.0001). By multivariate logistic analysis, the only clinical determinants related to outward remodeling was younger age, and only by definition 3. IVUS determinants varied significantly between the three definitions. The only consistent determinants among the three definitions were smaller lumen CSA at the reference site and larger plaque + media CSA at the lesion site. This study demonstrates the significant impact of different remodeling definitions on the incidence and determinants of remodeling patterns. The marked variability in categorization of remodeling underscores the importance of developing a standard methodology.

Effects of different application parameters on penetration characteristics and arterial vessel wall integrity after local nanoparticle delivery using a porous balloon catheter

Catheter-based local delivery of drug loaded nanoparticles agents offers a potential therapeutic approach to reducing restenosis. However, high delivery pressures and large volumes of infusates may cause severe vascular damage and increase intimal thickening. Therefore, we investigated the penetration pattern and vessel wall integrity of fluorescence-labelled nanoparticles (217 nm in diameter) into the non-atherosclerotic aorta abdominalis of New Zealand white rabbits in dependence of the volume (2.5 and 5 ml) and concentration (0.5 and 1 mg/ml) of the nanoparticle suspension, as well as the infusion pressure (2 and 4 atm) using a channelled balloon catheter (SCIMED REMEDY model RC 20/2.5). The location and penetration characteristics of nanoparticles in the arterial vessel wall were visualized using confocal laser scanning microscopy and transmission electron microscopy (TEM). Catheter design and infusion pressure form a radial particle stream through intima and media into the adventitial layer of the aorta abdominalis. Infusion pressures of 4 atm in combination with high particle concentrations lead to effective nanoparticle delivery without severe vessel wall disruptions. Endothelium of the treated vessel segments was slightly affected during catheter insertion showing partly denudation of the innermost cell layer. TEM micrographs underlines transport functional properties of the vasa vasorum inside the vessel wall. Consequently, local delivery efficiency of nanoparticulate carriers is critically affected by infusion pressure, and concentration of carrier suspensions. These factors need to be taken into consideration for the design of in vivo experiments.