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1.  Noninvasive In Vivo Characterization of Human Carotid Plaques with Acoustic Radiation Force Impulse (ARFI) Ultrasound: Comparison with Histology Following Endarterectomy 
Ultrasound in medicine & biology  2015;41(3):685-697.
Ischemic stroke from thromboembolic sources is linked to carotid artery atherosclerotic disease with a trend toward medical management in asymptomatic patients. Extent of disease is currently diagnosed by noninvasive imaging techniques that measure luminal stenosis, but it has been suggested that a better biomarker for determining risk of future thromboembolic events is plaque morphology and composition. Specifically, plaques that are composed of mechanically-soft lipid/necrotic regions covered by thin fibrous caps are the most vulnerable to rupture. An ultrasound technique that noninvasively interrogates the mechanical properties of soft tissue, called acoustic radiation force impulse (ARFI) imaging, has been developed as a new modality for atherosclerotic plaque characterization using phantoms and atherosclerotic pigs, but the technique has yet to be validated in vivo in humans. In this preliminary study, in vivo ARFI imaging is presented in a case-study format from four patients undergoing clinically-indicated carotid endarterectomy and compared to histology. In two type Va plaques, characterized by lipid/necrotic cores covered by fibrous caps, mean ARFI displacements in focal regions were high relative to the surrounding plaque material, suggesting soft features covered by stiffer layers within the plaques. In two type Vb plaques, characterized by heavy calcification, mean ARFI peak displacements were low relative to the surrounding plaque and arterial wall, suggesting stiff tissue. This pilot study demonstrates the feasibility and challenges of transcutaneous ARFI for characterizing the material and structural composition of carotid atherosclerotic plaques via mechanical properties, in humans, in vivo.
PMCID: PMC4331250  PMID: 25619778
atherosclerosis; stroke; plaque characterization; carotid endarterectomy; CEA; acoustic radiation force; ARFI; ultrasound
2.  Inflammatory cytokine levels in chronic venous insufficiency ulcer tissue before and after compression therapy 
Journal of vascular surgery  2009;49(4):1013-1020.
Elevated inflammatory cytokine levels have been implicated in the pathogenesis of non3 healing chronic venous insufficiency (CVI) ulcers. The goal of this study was to determine the protein levels of a wide range of inflammatory cytokines in untreated CVI ulcer tissue before and after 4 weeks of high strength compression therapy. These levels were compared to cytokines present in healthy tissue.
Thirty limbs with untreated CVI and leg ulceration received therapy for 4 weeks with sustained high compression bandaging at an ambulatory wound center. Biopsies were obtained from healthy and ulcerated tissue before and after therapy. A multiplexed protein assay was used to measure multiple cytokines in a single sample. Patients were designated as rapid or delayed healers based on ulcer surface area change.
The majority of pro-inflammatory cytokine protein levels were elevated in ulcer tissue compared to healthy tissue, and compression therapy significantly reduced these cytokines. TGF-β1 was up-regulated in ulcer tissue following compression therapy. Rapid healing ulcers had significantly higher levels of IL-1α, IL-1β, IFN-γ, IL-12p40 and GM-CSF before compression therapy, and IL-1 Ra after therapy. IFN-γ levels significantly decreased following therapy in the rapidly healing patients.
CVI ulcer healing is associated with a pro-inflammatory environment prior to treatment that reflects metabolically active peri-wound tissue that has the potential to heal. Treatment with compression therapy results in healing that is coupled with reduced pro-inflammatory cytokine levels and higher levels of the anti-inflammatory cytokine IL-1 Ra.
Clinical Relevance
This data suggests that cytokines may provide targets in which topical therapeutic inhibition or promotion at appropriate time points in the healing process may provide novel therapeutic approaches to the healing of CVI ulcers.
PMCID: PMC4710545  PMID: 19341889
Inflammation; cytokine; venous leg ulcer; compression therapy; multiplex analysis
3.  A Multicenter Randomized Controlled Trial Comparing Treatment of Venous Leg Ulcers Using Mechanically Versus Electrically Powered Negative Pressure Wound Therapy 
Advances in Wound Care  2015;4(2):75-82.
Objective: This study compares two different negative pressure wound therapy (NPWT) modalities in the treatment of venous leg ulcers (VLUs), the ultraportable mechanically powered (MP) Smart Negative Pressure (SNaP®) Wound Care System to the electrically powered (EP) Vacuum-Assisted Closure (V.A.C.®) System.
Approach: Patients with VLUs from 13 centers participated in this prospective randomized controlled trial. Each subject was randomly assigned to treatment with either MP NPWT or EP NPWT and evaluated for 16 weeks or complete wound closure.
Results: Forty patients (n=19 MP NPWT and n=21 EP NPWT) completed the study. Primary endpoint analysis of wound size reduction found wounds in the MP NPWT group had significantly greater wound size reduction than those in the EP NPWT group at 4, 8, 12, and 16 weeks (p-value=0.0039, 0.0086, 0.0002, and 0.0005, respectively). Kaplan–Meier analyses showed greater acceleration in complete wound closure in the MP NPWT group. At 30 days, 50% wound closure was achieved in 52.6% (10/19) of patients treated with MP NPWT and 23.8% (5/21) of patients treated with EP NPWT. At 90 days, complete wound closure was achieved in 57.9% (11/19) of patients treated with MP NPWT and 38.15% (8/21) of patients treated with EP NPWT.
Innovation: These data support the use of MP-NPWT for the treatment of VLUs.
Conclusions: In this group of venous ulcers, wounds treated with MP NPWT demonstrated greater improvement and a higher likelihood of complete wound closure than those treated with EP NPWT.
PMCID: PMC4322036  PMID: 25713749
5.  A Randomized, Controlled Pilot Study of Autologous CD34+ Cell Therapy for Critical Limb Ischemia 
Critical limb ischemia (CLI) portends a risk of major amputation of 25-35% within 1 year of diagnosis. Pre-clinical studies provide evidence that intramuscular injection of autologous CD34+ cells improve limb perfusion and reduce amputation risk. In this randomized, double-blind, placebo-controlled pilot study, we evaluated the safety and efficacy of intramuscular injections of autologous CD34+ cells in subjects with moderate or high-risk CLI who were poor or non-candidates for surgical or percutaneous revascularization (ACT34-CLI).
Methods and Results
Twenty-eight CLI subjects were randomized and treated: 7 to 1×105 (low-dose) and 9 to 1×106 (high-dose) autologous CD34+ cells/kg; 12 to placebo (control). Intramuscular injections were distributed into 8 sites within the ischemic lower extremity. At 6 months post-injection 67% of control subjects experienced a major or minor amputation versus 43% of low-dose and 22% of high-dose cell-treated subjects (P=0.137). This trend continued at 12 months with 75% of control subjects experiencing any amputation versus 43% of low-dose and 22% of high-dose cell-treated subjects (P=0.058). Amputation incidence was lower in the combined cell-treated groups compared with control group (6 months: P=0.125; 12 months: P=0.054), with the low-dose and high-dose groups individually showing trends towards improved amputation free survival at 6 and 12 months. No adverse safety signal was associated with cell administration.
This study provides evidence that intramuscular administration of autologous CD34+ cells was safe in this patient population. Favorable trends toward reduced amputation rates in cell-treated versus control subjects were observed. These findings warrant further exploration in later phase clinical trials.
PMCID: PMC3549397  PMID: 23192920
peripheral vascular disease; revascularization; reperfusion; randomized trial; stem cells
6.  Diabetic Foot Ulcers and Vascular Insufficiency: Our Population Has Changed, but Our Methods Have Not 
Diabetic foot complications are increasing in prevalence worldwide. Care and attention to these complications have improved greatly. Many advanced therapies are now being investigated or taken through final stages of clinical studies worldwide. However, the data upon which assumptions regarding morbidity, healing, and mortality have been based are grossly outdated. The purpose of this brief article is to report on current data regarding neuropathic and neuroischemic wounds and to propose that the latter category of advanced-stage diabetic foot wound may now be emerging as the most commonly encountered lesion in the developed world. Unfortunately, it is still systematically excluded from most clinical study criteria. Additionally, just as in the care of cancer, we call for therapy of these advanced-stage diabetic foot ulcers to be managed in similarly interdisciplinary centers where patients may have access to potentially beneficial clinical trials.
PMCID: PMC3262731  PMID: 22226282
amputation; diabetic foot ulcers; infection; ischemia; wound healing
7.  SNaP® Wound Care System: Ultraportable Mechanically Powered Negative Pressure Wound Therapy 
Advances in Wound Care  2012;1(1):41-43.
Negative pressure wound therapy (NPWT) is a well-accepted modality for treatment of difficult wounds, but has traditionally required a bulky electrically powered pump that was difficult to procure and use for both caregivers and patients. Often times, treatment of refractory smaller-sized wounds was impractical even though they may benefit from NPWT.
Spiracur (Sunnyvale, CA) has developed a simple, easy-to-use, single-use, off-the-shelf, mechanically powered NPWT device that weighs <3 ounces. This device allows for the practical treatment of smaller-sized wounds with NPWT designed specifically for the ambulatory patient being treated at home.
New Technology
The Smart Negative Pressure (SNaP®) Wound Care System is a novel light-weight NPWT device that does not require an electrically powered pump. Instead, the SNaP system utilizes specialized springs to generate a preset (−75, −100, and −125 mmHg) continuous subatmospheric pressure level to the wound bed. This technology has demonstrated similar efficacy and increased usability for both clinicians and patients when compared with electrically powered NPWT devices.
Indications for Use
Chronic, acute, traumatic, subacute, and dehisced wounds, partial-thickness burns, ulcers (such as diabetic or pressure), and surgically closed incisions and flaps.
Wounds with excess necrotic tissue, active infection, fistulas, exposed vital structures, untreated osteomyelitis, and that are highly exudative. The SNaP system was not designed for wounds that exceed the size of the dressing in surface area or have exudate levels greater than capacity of the cartridge.
PMCID: PMC3839001  PMID: 24527277
8.  Formulated collagen gel accelerates healing rate immediately after application in patients with diabetic neuropathic foot ulcers 
Wound Repair and Regeneration  2011;19(3):302-308.
We assessed the safety and efficacy of Formulated Collagen Gel (FCG) alone and with Ad5PDGF-B (GAM501) compared with Standard of Care (SOC) in patients with 1.5–10.0 cm2 chronic diabetic neuropathic foot ulcers that healed <30% during Run-in. Wound size was assessed by planimetry of acetate tracings and photographs in 124 patients. Comparison of data sets revealed that acetate tracings frequently overestimated areas at some sites. For per-protocol analysis, 113 patients qualified using acetate tracings but only 82 qualified using photographs. Prior animal studies suggested that collagen alone would have little effect on healing and would serve as a negative control. Surprisingly trends for increased incidence of complete closure were observed for both GAM501 (41%) and FCG (45%) vs. Standard of Care (31%). By photographic data, Standard of Care had no significant effect on change in wound radius (mm/week) from during Run-in to Week 1 (−0.06±0.32 to 0.78±1.53, p=ns) but both FCG (−0.08±0.61 to 1.97±1.77, p<0.002) and GAM501 (−0.02±0.58 to 1.46±1.37, p<0.002) significantly increased healing rates that gradually declined over subsequent weeks. Both GAM501 and FCG appeared to be safe and well tolerated, and alternate dosing schedules hold promise to improve overall complete wound closure in adequately powered trials.
PMCID: PMC3443373  PMID: 21371164
9.  Comparative effectiveness of a bilayered living cellular construct and a porcine collagen wound dressing in the treatment of venous leg ulcers 
Wound Repair and Regeneration  2014;22(3):334-340.
Using data from a national wound-specific electronic medical record (WoundExpert, Net Health, Pittsburgh, PA), we compared the effectiveness of a bilayered living cellular construct (BLCC) and an acellular porcine small intestine submucosa collagen dressing (SIS) for the treatment of venous leg ulcer. Data from 1,489 patients with 1,801 refractory venous leg ulcers (as defined by failure to have >40% reduction in size in the 4 weeks prior to treatment) with surface areas between 1 and 150 cm2 in size, treated between July 2009 and July 2012 at 158 wound care facilities across the US were analyzed. Patient baseline demographics and wound characteristics were comparable between groups. Kaplan-Meier–derived estimates of wound closure for BLCC (1,451 wounds) was significantly greater (p = 0.01, log-rank test) by weeks 12 (31% vs. 26%), 24 (50% vs. 41%), and 36 (61% vs. 46%), respectively, compared with SIS (350 wounds). BLCC treatment reduced the median time to wound closure by 44%, achieving healing 19 weeks sooner (24 vs. 43 weeks, p = 0.01, log-rank test). Treatment with BLCC increased the probability of healing by 29% compared with porcine SIS dressing (hazard ratio = 1.29 [95% confidence interval 1.06, 1.56], p = 0.01).
PMCID: PMC4257085  PMID: 24628712

Results 1-9 (9)