Safety and efficacy of Everolimus-Eluting bioabsorbable Polymer-Coated stent in patients with long coronary lesions: The EVOLVE 48 study.

OBJECTIVES: The EVOLVE 48 study evaluated the safety and effectiveness of the SYNERGY 48 mm stent for the treatment of long lesions. BACKGROUND: Clinical evidence supporting the use of very long stents during percutaneous coronary intervention (PCI) is limited. The bioabsorbable polymer SYNERGY stent has shown good long-term data in a broad population of patients undergoing PCI. METHODS: Patients with lesion length >34- ≤44 mm and reference vessel diameter (RVD) ≥2.5- ≤ 4.0 mm were enrolled in this prospective, multicenter, single-arm study. The primary endpoint was 12-month target lesion failure (TLF; composite of target lesion revascularization [TLR], target-vessel myocardial infarction [TV-MI], or cardiac death) compared to a prespecified performance goal (PG). RESULTS: A total of 100 patients with mean lesion length of 35.34 ± 7.15 mm (26 patients with lesion length > 40 mm) and mean RVD 2.72 ± 0.44 mm were enrolled. Moderate to severe calcification was present in 30% of the patients and 89% had pre-TIMI flow grade 3. The rates of technical and clinical procedural success were 100%. One-year TLF was observed in 4.1% patients compared to a prespecified PG of 19.5% (95% upper confidence bound = 9.1%; p < 0.0001). Cardiac death and TLR were each observed in one patient, and TV-MI in two patients treated with SYNERGY 48 mm stent. Between the 1-2-year timeframe, TV-MI occurred in one additional patient. None of the patients experienced a definite or probable stent thrombosis through 2 years. CONCLUSIONS: PCI of long coronary lesions with the 48 mm SYNERGY stent demonstrated good procedural and clinical outcomes through 2 years, supporting its clinical safety and efficacy.

Percutaneous Coronary Intervention for Left Main Coronary Disease in New Zealand: National Linkage Study of Characteristics and In-Hospital Outcomes (ANZACS-QI 38).

BACKGROUND: Approximately 5% of coronary angiographies detect LMS disease >50%. Recent randomized trials showed PCI has comparable outcomes to coronary artery bypass grafting (CABG) in low or intermediate risk candidates. In clinical practice, PCI is frequently utilized in those with prohibitive surgical risk. We reviewed contemporary national results of percutaneous coronary intervention (PCI) for left main coronary disease (LMS) disease in New Zealand. METHODS: All patients undergoing PCI for LMS disease from 01/09/2014-24/09/2017 were extracted from the All New Zealand Acute Coronary Syndrome-Quality Improvement registry with national dataset linkage, analyzing characteristics and in-hospital outcomes. RESULTS: The cohort included 469 patients, mean age 70.8 ±â€¯10.7 years, male 331 (71%), and the majority 339 (72%) were unprotected LMS. Indications include ST-elevation myocardial infarction (STEMI) 83 (18%) and NSTEMI or unstable angina 229 (49%). Compared with protected LMS, unprotected LMS were more likely to present with an acute coronary syndrome (73% versus 48%, P < 0.001), and to die in-hospital (9.4% versus 3.9%, P = 0.045). In those with unprotected LMS, in-hospital mortality after acute STEMI PCI was higher than for other indications (21.1% versus 6.1%, P < 0.001). Independent predictors of in-hospital death and major adverse cardiovascular events included STEMI, femoral access and worse renal function. CONCLUSION: Our LMS PCI cohort had high mortality rates, especially those presenting with STEMI and an unprotected LMS. This reflects the contemporary real-world practice of LMS PCI being predominantly performed in high risk patients which differs from randomized trial populations, and this should be considered before comparing with CABG outcomes.

Coronary artery perforation successfully treated with tris-acryl gelatin microsphere embolisation.

We describe a case of coronary artery perforation in a 76-year-old man, successfully treated by tris-acryl gelatin microsphere embolisation. This novel interventional embolic material is used in interventional radiology for arterial embolisation. We believe that this is the first report of its use for a coronary artery perforation.

An independent bench comparison of two bioresorbable drug-eluting coronary scaffolds (Absorb and DESolve) with a durable metallic drug-eluting stent (ML8/Xpedition).

AIMS: We compared the mechanical and physical properties and the safety from strut fracture of side branch and post-dilatation strategies for the Absorb and DESolve bioresorbable scaffolds with the durable metallic drug-eluting XIENCE Xpedition stent using largely independent bench testing. METHODS AND RESULTS: The strut thickness and crossing profile of the polymeric scaffolds was greater than those of the metallic drug-eluting stent. While all three devices recoiled after deployment, the DESolve enlarged between 10 mins and one hour returning to the immediate post-deployment diameter ("self-correction"). In 3.0 mm stents/scaffolds, the main branch post-dilatation safe threshold without fracture for Absorb was 3.8 mm at 20 atm, for DESolve was 5.0 mm at 20 atm whereas the ML8 did not fracture. For side branch dilatation with a 3.0 mm non-compliant balloon, the threshold before the Absorb fractured was 10 atm whereas the DESolve and ML8 did not fracture at 22 atm. The safe threshold for mini-kissing balloon post-dilatation in 3.0 mm scaffolds/stents with 3.0 mm non-compliant balloons was 5 atm for the Absorb whereas the DESolve and ML8 did not fracture up to 20 atm. CONCLUSIONS: The metallic stent has thinner struts, lower profile, and greater radial strength than the polymeric scaffolds. Different safe pressure thresholds exist for different scaffolds/stents. Unlike the others, the DESolve showed "self-correction" or enlargement after initial recoil.

A next-generation bioresorbable coronary scaffold system: from bench to first clinical evaluation: 6- and 12-month clinical and multimodality imaging results.

OBJECTIVES: This study sought to perform clinical and imaging assessments of the DESolve Bioresorbable Coronary Scaffold (BCS). BACKGROUND: BCS, which is drug eluting, may have potential advantages compared with conventional metallic drug-eluting stents. The DESolve system, designed to provide vessel support and neointimal suppression, combines a poly-l-lactic acid-based scaffold with the antiproliferative myolimus. METHODS: The DESolve First-in-Man (a non-randomized, consecutive enrollment evaluation of the DESolve myolimus eluting bioresorbable coronary stent in the treatment of patients with de novo native coronary artery lesions) trial was a prospective multicenter study enrolling 16 patients eligible for treatment. The principal safety endpoint was a composite of cardiac death, myocardial infarction, and clinically indicated target lesion revascularization. The principal imaging endpoint was in-scaffold late lumen loss (LLL) assessed by quantitative coronary angiography (QCA) at 6 months. Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) imaging was performed at baseline and 6 months; multislice computed tomography (MSCT) was performed at 12 months. RESULTS: Acute procedural success was achieved in 15 of 15 patients receiving a study scaffold. At 12 months, there was no scaffold thrombosis and no major adverse cardiac events directly attributable to the scaffold. At 6 months, in-scaffold LLL (by QCA) was 0.19 ± 0.19 mm; neointimal volume (by IVUS) was 7.19 ± 3.56%, with no evidence of scaffold recoil or late malapposition. Findings were confirmed with OCT and showed uniform, thin neointimal coverage (0.12 ± 0.04 mm). At 12 months, MSCT demonstrated excellent vessel patency. CONCLUSIONS: This study demonstrated the feasibility and efficacy of the DESolve BCS. Results showing low in-scaffold LLL, low % neointimal volume at 6 months, no chronic recoil, and maintenance of lumen patency at 12 months prompt further study. (DESolve First-in-Man; EudraCT number 2011-000027-32).

First-in-human evaluation of a sirolimus-eluting coronary stent on an integrated delivery system: the DIRECT study.

AIMS: The DIRECT study is a first-in-human evaluation of the safety and efficacy of the Svelte sirolimus-eluting coronary stent mounted on a fixed-wire, "all-in-one" integrated delivery system (IDS) in patients with de novo coronary artery lesions. The system permits easy delivery, deployment and post-dilatation of a cobalt-chromium stent eluting sirolimus from a fully bioabsorbable amino acid coating. The stent on its IDS has a very low profile, and is designed specifically to facilitate direct stenting. METHODS AND RESULTS: Patients with symptomatic ischaemic heart disease and a single de novo native coronary lesion suitable for percutaneous coronary intervention were prospectively enrolled at four New Zealand sites. The lesion length had to be <23 mm and the vessel reference diameter 2.5-3.5 mm. The primary safety and efficacy endpoints were target vessel failure (TVF) and angiographic in-stent late lumen loss (LLL) at six months, respectively. Twenty-nine of 30 enrolled patients completed six-month follow-up. TVF occurred in two patients (7%). The in-stent LLL was 0.22 ± 0.27 mm. No patient had clinically-driven target lesion revascularisation. Intravascular ultrasound neointimal volume was 3.3 ± 4.4 mm3 and volume obstruction was 2.7 ± 4.5% at six months. Optical coherence tomography showed 98 ± 4% strut coverage at a depth of 0.12 ± 0.06 mm. No patient developed stent thrombosis. CONCLUSIONS: Percutaneous coronary intervention using the Svelte sirolimus-eluting coronary stent mounted on an IDS appears safe and effective in de novo coronary artery lesions, with minimal in-stent proliferation and excellent stent strut coverage at six months.

Five-year clinical and functional multislice computed tomography angiographic results after coronary implantation of the fully resorbable polymeric everolimus-eluting scaffold in patients with de novo coronary artery disease: the ABSORB cohort A trial.

OBJECTIVES: This study sought to demonstrate the 5-year clinical and functional multislice computed tomography angiographic results after implantation of the fully resorbable everolimus-eluting scaffold (Absorb BVS, Abbott Vascular, Santa Clara, California). BACKGROUND: Multimodality imaging of the first-in-humans trial using a ABSORB BVS scaffold demonstrated at 2 years the bioresorption of the device while preventing restenosis. However, the long-term safety and efficacy of this therapy remain to be documented. METHODS: In the ABSORB cohort A trial (ABSORB Clinical Investigation, Cohort A [ABSORB A] Everolimus-Eluting Coronary Stent System Clinical Investigation), 30 patients with a single de novo coronary artery lesion were treated with the fully resorbable everolimus-eluting Absorb scaffold at 4 centers. As an optional investigation in 3 of the 4 centers, the patients underwent multislice computed tomography (MSCT) angiography at 18 months and 5 years. Acquired MSCT data were analyzed at an independent core laboratory (Cardialysis, Rotterdam, the Netherlands) for quantitative analysis of lumen dimensions and was further processed for calculation of fractional flow reserve (FFR) at another independent core laboratory (Heart Flow, Redwood City, California). RESULTS: Five-year clinical follow-up is available for 29 patients. One patient withdrew consent after 6 months, but the vital status of this patient remains available. At 46 days, 1 patient experienced a single episode of chest pain and underwent a target lesion revascularization with a slight troponin increase after the procedure. At 5 years, the ischemia-driven major adverse cardiac event rate of 3.4% remained unchanged. Clopidogrel was discontinued in all but 1 patient. Scaffold thrombosis was not observed in any patient. Two noncardiac deaths were reported, 1 caused by duodenal perforation and the other from Hodgkin's disease. At 5 years, 18 patients underwent MSCT angiography. All scaffolds were patent, with a median minimal lumen area of 3.25 mm(2) (interquartile range: 2.20 to 4.30). Noninvasive FFR analysis was feasible in 13 of 18 scans, which yielded a median distal FFR of 0.86 (interquartile range: 0.82 to 0.94). CONCLUSIONS: The low event rate at 5 years suggests sustained safety after the implantation of a fully bioresorbable Absorb everolimus-eluting scaffold. Noninvasive assessment of the coronary artery with an option of functional assessment could be an alternative to invasive imaging after treatment of coronary narrowing with such a polymeric bioresorbable scaffold. (ABSORB Clinical Investigation, Cohort A [ABSORB A] Everolimus-Eluting Coronary Stent System Clinical Investigation [ABSORB]; NCT00300131).

First-in-human evaluation of a bioabsorbable polymer-coated sirolimus-eluting stent: imaging and clinical results of the DESSOLVE I Trial (DES with sirolimus and a bioabsorbable polymer for the treatment of patients with de novo lesion in the native coronary arteries).

OBJECTIVES: This first-in-human multicenter study sought to examine prospectively the safety and efficacy of a new, cobalt chromium thin-strut, coronary absorbable polymer-coated, sirolimus-eluting stent. BACKGROUND: Bioabsorbable polymers on drug-eluting stents may lower the long-term risks of inflammation, delayed healing, and adverse events. METHODS: We enrolled patients with symptomatic coronary artery disease with stable or unstable angina pectoris and >50% diameter stenosis, amenable to coverage with a ≤23-mm long stent in a vessel 2.5 to 3.5 mm in diameter. All patients received dual antiplatelet therapy after implantation. Patients, in groups of 10, underwent repeat angiography, intravascular ultrasound, and optical coherence tomography at 4, 6, or 8 months, and all patients were seen or contacted at 18 months of follow-up. RESULTS: The median (range) in-stent late lumen loss (LLL) was 0.03 mm (-0.22 to 0.21 mm), 0.10 mm (-0.03 to 1.2 mm), and 0.08 mm (-0.01 to 0.28 mm), at 4, 6, and 8 months, respectively. At 18 months, the median in-stent LLL was 0.08 mm (-0.30 to 0.46 mm). On optical coherence tomography, the proportion of uncovered stent struts decreased from a median of 7.3% (range 0.4% to 46.3%) at 4 months to 0% (range: 0% to 3.4%) at 18 months. The percentage of neointimal volume obstruction by intravascular ultrasound increased from a median of 5.3% to 9.1% between 4 and 6 months and remained nearly unchanged thereafter through 18 months of follow-up. The only recorded major adverse cardiac event was a myocardial infarction. CONCLUSIONS: At 18 months of follow-up, this absorbable polymer-coated, cobalt chromium sirolimus-eluting stent was associated with a low and stable in-stent LLL, complete strut coverage, and no stent thrombosis. (First-In-Human Trial of the MiStent Drug-Eluting Stent [DES] in Coronary Artery Disease [DESSOLVE-I]; NCT01247428).

Stent longitudinal integrity bench insights into a clinical problem.

OBJECTIVES: Standardized bench-top compression and elongation testing was undertaken to assess the longitudinal strength of contemporary stents. Insights gained may improve clinical stent choice and deployment techniques, and facilitate future stent design improvements. BACKGROUND: The hoops of coronary stents provide radial support, and connectors hold hoops together. Strut material, shape, and thickness, along with connector number and configuration, provide the balance between stent flexibility and longitudinal integrity. Longitudinal distortion manifests as length change, strut overlap, strut separation, malapposition, and luminal obstruction. These may predispose to restenosis and stent thrombosis, obstruct passage of devices, be misinterpreted as strut fracture, and require additional stenting. METHODS: The force required to compress and to elongate 7 contemporary stents was measured with an Instron universal testing machine (Norwood, Massachusetts). Stents deployed in a silicone phantom damaged by a balloon or guide catheter were imaged by microcomputed tomography to understand better the appearances and effects of longitudinal distortion. RESULTS: Stents with 2 connectors (Boston Scientific [Natick, Massachusetts] Omega and Medtronic [Santa Rosa, California] Driver) required significantly less force to be compressed up to 5 mm and elongated by 1 mm than designs with more connectors. The 6-connector Cypher Select required significantly more force to be elongated 5 mm than other designs. CONCLUSIONS: Stents with 2 connectors between hoops have less longitudinal strength when exposed to compressing or elongating forces than those with more connectors. This independent, standardized study may assist stent selection in clinical situations where longitudinal integrity is important, and may aid future design improvements. Stent longitudinal strength, the resistance to shortening or elongation, appears related to the number of connectors between hoops. Using a standardized testing protocol, designs with 2 connectors were more likely to shorten or elongate than those with more connectors. Distortion may be recognized clinically as bunching or separation of struts, and may be confused with strut fracture. Without post-dilation or further stent deployment, the patient may be at increased risk for adverse clinical events. A stent design change ensuring 3 connectors, especially at the proximal end of a stent, should increase longitudinal integrity, but perhaps at the expense of stent flexibility.

Monitoring in vivo absorption of a drug-eluting bioabsorbable stent with intravascular ultrasound-derived parameters a feasibility study.

OBJECTIVES: The aim of this study was to investigate the feasibility of using quantitative differential echogenicity to monitor the in vivo absorption process of a drug-eluting poly-l-lactic-acid (PLLA) bioabsorbable stent (BVS, Abbott Vascular, Santa Clara, California). BACKGROUND: A new bioabsorbable, balloon-expanded coronary stent was recently evaluated in a first-in-man study. Little is known about the absorption process in vivo in diseased human coronary arteries. METHODS: In the ABSORB (Clinical Evaluation of the BVS everolimus eluting stent system) study, 30 patients underwent treatment with the BVS coronary stent system and were examined with intracoronary ultrasound (ICUS) after implantation, at 6 months and at 2-year follow-up. Quantitative ICUS was used to measure dimensional changes, and automated ICUS-based tissue composition software (differential echogenicity) was used to quantify plaque compositional changes over time in the treated regions. RESULTS: The BVS struts appeared as bright hyperechogenic structures and showed a continuous decrease of their echogenicity over time, most likely due to the polymer degradation process. In 12 patients in whom pre-implantation ICUS was available, at 2 years the percentage-hyperechogenic tissue was close to pre-implantation values, indicating that the absorption process was either completed or the remaining material was no longer differentially echogenic from surrounding tissues. CONCLUSIONS: Quantitative differential echogenicity is a useful plaque compositional measurement tool. Furthermore, it seems to be valuable for monitoring the absorption process of bioabsorbable coronary stents made of semi-crystalline polymers.

Feasibility, safety, and efficacy of a novel polymeric pimecrolimus-eluting stent: traditional pre-clinical safety end points failed to predict 6-month clinical angiographic results.

OBJECTIVES: The aim of this study was to determine the safety and efficacy of a novel pimecrolimus-eluting stent in a porcine coronary model and in a phase I clinical trial. BACKGROUND: Rapamycin- and paclitaxel-eluting stents reduce the need for repeat intervention by limiting neointimal hyperplasia but might cause delayed healing, pre-disposing patients to late stent thrombosis. Because inflammation plays a key role in restenosis, pimecrolimus, an anti-inflammatory drug, might reduce restenosis without adversely affecting re-endothelialization. METHODS: We evaluated a novel polymeric pimecrolimus-eluting stent covered with a thin parylene C diffusion barrier in a porcine coronary model and in a phase I human clinical trial. The clinical study was a prospective, nonrandomized, first-in-human hypothesis-generating study that enrolled 15 patients who had a single de novo native coronary stenosis. RESULTS: At 28 days and 3 months in the porcine model, histopathologic indicators predicted safety and biocompatibility when stents coated with polymer only, drug only, and 2 drug-polymer formulations were compared with bare-metal stents (BMS). In the phase I clinical trial, 15 patients had successful implantation of pimecrolimus-eluting stents. By 6 months, no patient suffered death, myocardial infarction, or stent thrombosis. However, the angiographic restenosis (61%), mean late loss (1.44 mm), and repeat target lesion revascularization (53%) were significantly higher than historical BMS controls. Whereas the primary end point was percent volume obstruction, restenosis was so severe that operators performed intravascular ultrasound examination in only 6 patients. CONCLUSIONS: Pimecrolimus-eluting stents induced an exaggerated neointimal hyperplasia at 6 months in comparison with historical controls.

The "crush" technique for coronary artery bifurcation stenting: insights from micro-computed tomographic imaging of bench deployments.

OBJECTIVES: This study provides insights into "crush" coronary bifurcation stenting through imaging of bench deployments. BACKGROUND: Although the strategy of provisional side-branch stenting is widely accepted for suitable bifurcation lesions, there is no consensus on the best option for elective stenting with 2 stents. The crush technique has the potential to scaffold and apply the drug to the side-branch ostium where restenosis is most common. METHODS: Sequential steps of crush stent deployment and post-dilation were undertaken in silicone phantoms and recorded on cine angiography and microcomputed tomography. We assessed the effect of deployment strategies, post-dilation strategies, and cell size on side-branch ostial area. RESULTS: Side-branch ostial coverage by metal struts was 53% (95% confidence interval [CI]: 46 to 59) after 1-step kissing post-dilation and was reduced by 2-step kissing post-dilation to 33% (95% CI: 28 to 37; p < 0.0001). Although the residual stenosis after the classical crush strategy was 47% (95% CI: 39 to 53), it was 36% (95% CI: 31 to 40; p = 0.002) after mini-crush deployment. Stents with larger cell size (>3.5 mm diameter) had a residual stenosis of 37% (95% CI: 32 to 42) after crush deployment that was less than the residual stenosis for stents with smaller cell size (52%; 95% CI: 44 to 60; p < 0.0001). CONCLUSIONS: Side-branch ostial stenosis after crush stenting was minimized by mini-crush deployment, 2-step kissing post-dilation, and the use of stents with larger cell size. It is unknown if optimizing stent deployment at bifurcation lesions will reduce clinical stent thrombosis and restenosis.

First-in-human implantation of a fully bioabsorbable drug-eluting stent: the BVS poly-L-lactic acid everolimus-eluting coronary stent.

The first-in-human fully bioabsorbable drug-eluting stent (BVS poly-L-lactic acid everolimus-eluting coronary stent) implantation was performed at Auckland City Hospital, New Zealand as part of the ABSORB trial. There were no adverse events in-hospital or by 1 month. A stent that supports the vessel when needed, delivers an antiproliferative drug then disappears has theoretical advantages with regard to CT and MRI compatibility, restored vessel vasomotion, and facilitated future percutaneous intervention or surgical grafting to the treated site.

Polymer-based, paclitaxel-eluting TAXUS Liberté stent in de novo lesions: the pivotal TAXUS ATLAS trial.

OBJECTIVES: The goal of this research was to assess non-inferiority of the next-generation TAXUS Liberté stent (Boston Scientific Corp., Natick, Massachusetts) versus the TAXUS Express stent (Boston Scientific Corp.). BACKGROUND: The introduction of drug-eluting stents (DES) has shifted clinical practice towards more complex lesion subsets, prompting the need for more deliverable DES. TAXUS Liberté was designed to combine the established polymer-based, paclitaxel-elution TAXUS technology with the more advanced Liberté stent platform. METHODS: The TAXUS ATLAS study is a global, prospective, single-arm trial evaluating outcomes in de novo coronary lesions visually estimated to be 10 to 28 mm in length in vessels 2.5 to 4.0 mm in diameter. The control group is an entry-criteria-matched population of TAXUS Express patients from the TAXUS IV and V trials. The primary end point is non-inferiority of TAXUS Liberté versus TAXUS Express for 9-month target vessel revascularization. RESULTS: Despite similar inclusion criteria, quantitative coronary angiography-determined baseline lesion characteristics were significantly more complex for TAXUS Liberté than TAXUS Express. The primary non-inferiority end point was met with the 1-sided 95% confidence bound of 2.98% less than the pre-specified non-inferiority margin of 3% (p = 0.0487). CONCLUSIONS: Despite the treatment of more complex lesions with TAXUS Liberté, the primary end point was met, demonstrating that TAXUS Liberté is non-inferior to TAXUS Express. The successful transfer of the proven TAXUS technology to the more advanced TAXUS Liberté platform was demonstrated. (TAXUS ATLAS: TAXUS Liberté-SR Stent for the Treatment of De Novo Coronary Artery Lesions; http://www.clinicaltrials.gov/ct/show/NCT00371709?order=1; NCT00371709).

IMPACT Trial: angiographic and intravascular ultrasound observations of the first human experience with mycophenolic acid-eluting polymer stent system.

The purpose of the study was to examine the safety and efficacy of two different formulations of mycophenolic acid (MPA)-eluting Duraflex stents on coronary de novo lesions. Recent data indicate that local delivery of MPA in the porcine overstretch coronary model significantly reduces neointimal hyperplasia (NIH). Patients were divided into three consecutive groups. The first (n=50) and second (n=55) groups received moderate- and slow-release MPA-eluting Duraflex stent, respectively. The last group (n=50) received the bare metal Duraflex stent. Clinical, angiographic, and intravascular ultrasound analysis were performed at 6-month follow-up. All stents were successfully deployed and patients were discharged home without clinical events. Compared to controls, 6-month in-lesion and in-stent minimum luminal diameter as well as late lumen loss were not significantly different in the moderate- and slow-release treatment groups. At follow-up, percentage obstruction and NIH volume were also similar between the three groups. At 30 days and 6 and 12 months, there were no differences noted between the three groups with respect to major adverse cardiac events as well as the individual rates of mortality, myocardial infarction, or repeat revascularization. There were no cases of subacute or late thrombosis. In this feasibility trial, the MPA-eluting Duraflex stents in either slow- or moderate-release formulations were well tolerated, but showed no benefit for treatment of coronary lesions when compared to controls. Further testing with different drug dosing or delivery rate might improve these results.