Carmelo J. Panetta

Smooth Muscle Progenitor Cells in Human Blood

Background—Recent animal data suggest that vascular smooth muscle cells within the neointima of the vessel wall may originate from bone marrow, providing indirect evidence for circulating smooth muscle progenitor cells (SPCs). Evidence for circulating SPCs in human subjects does not exist, and the mechanism whereby such putative SPCs may home to sites of plaque formation is presently not understood but is likely to involve expression of specific surface adhesion molecules, such as integrins. In this study, we aimed to culture smooth muscle outgrowth cells (SOCs) from SPCs in human peripheral blood and characterize surface integrin expression on these cells. Methods and Results—Human mononuclear cells isolated from buffy coat were seeded on collagen type 1 matrix and outgrowth cells selected in endothelial growth medium (EGM-2) or EGM-2 and platelet-derived growth factor BB. Selection in platelet-derived growth factor BB–enriched medium caused rapid outgrowth and expansion of SOC to >40 population doublings in a 4-month period. These SOCs were positive for smooth muscle cell–specific &agr; actin (&agr;SMA), myosin heavy chain, and calponin on immunofluorescence and Western blotting and were also positive for CD34, Flt1, and Flk1 receptor but negative for Tie-2 receptor expression, suggesting a potential bone marrow angioblastic origin. In contrast, endothelial outgrowth cells (EOCs) grown in EGM-2 alone and the initial MNC population were negative for these smooth muscle–specific markers. Integrin &agr;5&bgr;1 expression by FACS and Western blotting was significantly increased in SOCs compared with EOCs, and this was confirmed by 8-fold greater adhesion of SOC to fibronectin (P <0.001), an effect that could be decreased using an &agr;5&bgr;1 antibody. Finally, SOC showed a significantly greater in vitro proliferative potential compared with EOCs of similar passage (P <0.001). Conclusions—This study demonstrates for the first time outgrowth of smooth muscle cells with a specific growth, adhesion, and integrin profile from putative SPC in human blood. These data have implications for our understanding of adult vascular smooth muscle cell differentiation, proliferation, and homing. (Circulation. 2002;106:1199–1204.)

Bioenergetic and Functional Consequences of Bone Marrow–Derived Multipotent Progenitor Cell Transplantation in Hearts With Postinfarction Left Ventricular Remodeling

Background— The present study examined whether transplantation of adherent bone marrow-derived stem cells, termed pMultistem, induces neovascularization and cardiomyocyte regeneration that stabilizes bioenergetic and contractile function in the infarct zone and border zone (BZ) after coronary artery occlusion. Methods and Results— Permanent left anterior descending artery occlusion in swine caused left ventricular remodeling with a decrease of ejection fraction from 55±5.6% to 30±5.4% (magnetic resonance imaging). Four weeks after left anterior descending artery occlusion, BZ myocardium demonstrated profound bioenergetic abnormalities, with a marked decrease in subendocardial phosphocreatine/ATP (31P magnetic resonance spectroscopy; 1.06±0.30 in infarcted hearts [n=9] versus 1.90±0.15 in normal hearts [n=8; P<0.01]). This abnormality was significantly improved by transplantation of allogeneic pMultistem cells (subendocardial phosphocreatine/ATP to 1.34±0.29; n=7; P<0.05). The BZ protein expression of creatine kinase-mt and creatine kinase-m isoforms was significantly reduced in infarcted hearts but recovered significantly in response to cell transplantation. MRI demonstrated that the infarct zone systolic thickening fraction improved significantly from systolic “bulging” in untreated animals with myocardial infarction to active thickening (19.7±9.8%, P<0.01), whereas the left ventricular ejection fraction improved to 42.0±6.5% (P<0.05 versus myocardial infarction). Only 0.35±0.05% donor cells could be detected 4 weeks after left anterior descending artery ligation, independent of cell transplantation with or without immunosuppression with cyclosporine A (with cyclosporine A, n=6; no cyclosporine A, n=7). The fraction of grafted cells that acquired an endothelial or cardiomyocyte phenotype was 3% and ≈2%, respectively. Patchy spared myocytes in the infarct zone were found only in pMultistem transplanted hearts. Vascular density was significantly higher in both BZ and infarct zone of cell-treated hearts than in untreated myocardial infarction hearts (P<0.05). Conclusions— Thus, allogeneic pMultistem improved BZ energetics, regional contractile performance, and global left ventricular ejection fraction. These improvements may have resulted from paracrine effects that include increased vascular density in the BZ and spared myocytes in the infarct zone.

Incidence, correlates, management, and clinical outcome of coronary perforation: analysis of 16,298 procedures

BACKGROUND Coronary perforation is a serious but uncommon complication of percutaneous coronary intervention (PCI) and is associated with significant morbidity and mortality. METHODS We performed an analysis of the Mayo Clinic PCI database. Clinical records, procedural reports, and angiographic studies were reviewed. Multiple logistic regression analysis was performed to identify clinical, procedural, anatomic, and angiographic correlates of coronary perforation. RESULTS A total of 16,298 PCI procedures were performed between January 1990 and December 2001. We identified 95 coronary perforations (0.58%; 95% CI, 0.47-0.71). The incidence of coronary perforation varied with time. Correlates of coronary perforation included the use of an atheroablative device and female sex. Twelve patients (12.6%) sustained an acute myocardial infarction, and cardiac tamponade developed in 11 patients (11.6%). Management strategies included reversal of heparin, pericardiocentesis, placement of a covered stent, and surgical repair. Seven patients died (7.4%). CONCLUSIONS Coronary perforation during PCI is rare, but is associated with significant morbidity and mortality. The variable frequency of perforation may be explained by temporal variations in the use of atheroablative devices.

Stem Cells for Myocardial Repair With Use of a Transarterial Catheter

Background— Using a swine model of postinfarction left ventricle (LV) remodeling, we investigated marrow-derived, multipotent progenitor cell (MPC) transplantation into hearts with acute myocardial infarction (AMI) via a novel transarterial catheter. Methods and Results— The left anterior descending coronary artery was balloon-occluded after percutaneous transluminal angiography to generate AMI (60-minute no-flow ischemia). The transarterial catheter was then placed in the same coronary artery, and either 50×106 MPCs (cell group, n=6) or saline (control, n=6) was injected into the border zone (BZ) myocardium. LV function was assessed by magnetic resonance imaging before AMI and at 1 and 4 weeks after AMI, whereas myocardial energy metabolism was assessed by 31P-magnetic resonance spectroscopy at week 4. One week after AMI, the ejection fraction was significantly reduced in both groups from a baseline of ≈50% to 31.3±3.9% (cell group) and 33.3±3.1% (control). However, at week 4, the cell group had a significant recovery in ejection fraction. The functional improvements were accompanied by a significant improvement in myocardial bioenergetics. Histologic data demonstrated a 0.55% cell engraftment rate 4 weeks after MPC transplantation. Only 2% of engrafted cells were costaining positive for cardiogenic markers. Vascular density in the BZ was increased in the cell group. Conditioned medium from cultured MPCs contained high levels of vascular endothelial growth factor, which was increased in response to hypoxia. MPCs cocultured with cardiomyocytes inhibited changes in cardiomyocyte mitochondrial membrane potential and cytochrome c release induced by tumor necrosis factor-&agr;. Conclusions— Thus, a paracrine effect may contribute significantly to the observed therapeutic effects of MPC transplantation.

A Tissue-Engineered Stent for Cell-Based Vascular Gene Transfer

Cell-based gene transfer using a stent platform would provide a significant advantage in terms of site-specific gene expression in the vasculature. The current study presents a novel stent design that allows stable in vivo transgene expression over a 4-week period in the vasculature. A mesh-stent coated with fibronectin provided an excellent platform for adherent porcine smooth muscle cells (SMC). Autologous porcine SMC were stably transduced with a plasmid encoding green fluorescence protein (GFP), seeded at high density in the mesh-stent, and deployed in the porcine coronary artery. Stable in vivo GFP expression within the mesh-stent (5.2 x 10(5) GFP-positive cells/cm(2) mesh) was demonstrated 1 month after implantation in the porcine coronary artery by fluorescence microscopy and flow cytometry. No significant change in GFP positive cell number within the stent occurred over a 1-month period in vivo when compared to preinsertion. Angiographic and histologic analysis revealed mild neointimal proliferation and no inflammatory infiltrate in the stented segment. This study has implications for treatment of cardiovascular and other diseases where long-term cell-based delivery of transgene is a desirable therapeutic option.

Early Access to the Cardiac Catheterization Laboratory for Patients Resuscitated From Cardiac Arrest Due to a Shockable Rhythm: The Minnesota Resuscitation Consortium Twin Cities Unified Protocol

Background In 2013 the Minnesota Resuscitation Consortium developed an organized approach for the management of patients resuscitated from shockable rhythms to gain early access to the cardiac catheterization laboratory (CCL) in the metro area of Minneapolis‐St. Paul. Methods and Results Eleven hospitals with 24/7 percutaneous coronary intervention capabilities agreed to provide early (within 6 hours of arrival at the Emergency Department) access to the CCL with the intention to perform coronary revascularization for outpatients who were successfully resuscitated from ventricular fibrillation/ventricular tachycardia arrest. Other inclusion criteria were age >18 and <76 and presumed cardiac etiology. Patients with other rhythms, known do not resuscitate/do not intubate, noncardiac etiology, significant bleeding, and terminal disease were excluded. The primary outcome was survival to hospital discharge with favorable neurological outcome. Patients (315 out of 331) who were resuscitated from VT/VF and transferred alive to the Emergency Department had complete medical records. Of those, 231 (73.3%) were taken to the CCL per the Minnesota Resuscitation Consortium protocol while 84 (26.6%) were not taken to the CCL (protocol deviations). Overall, 197 (63%) patients survived to hospital discharge with good neurological outcome (cerebral performance category of 1 or 2). Of the patients who followed the Minnesota Resuscitation Consortium protocol, 121 (52%) underwent percutaneous coronary intervention, and 15 (7%) underwent coronary artery bypass graft. In this group, 151 (65%) survived with good neurological outcome, whereas in the group that did not follow the Minnesota Resuscitation Consortium protocol, 46 (55%) survived with good neurological outcome (adjusted odds ratio: 1.99; [1.07–3.72], P=0.03). Conclusions Early access to the CCL after cardiac arrest due to a shockable rhythm in a selected group of patients is feasible in a large metropolitan area in the United States and is associated with a 65% survival rate to hospital discharge with a good neurological outcome.

Cutting balloon angioplasty vs. conventional balloon angioplasty in patients receiving intracoronary brachytherapy for the treatment of in-stent restenosis

The objective of this study was to evaluate the safety and efficacy of cutting balloon angioplasty (CBA) for the treatment of in‐stent restenosis prior to intracoronary brachytherapy (ICB). Cutting balloon angioplasty may reduce the incidence of uncontrolled dissection requiring adjunctive stenting and may limit “melon seeding” and geographic miss in patients with in‐stent restenosis who are subsequently treated with ICB. We performed a retrospective case‐control analysis of 134 consecutive patients with in‐stent restenosis who were treated with ICB preceded by either CBA or conventional balloon angioplasty. We identified 44 patients who underwent CBA and ICB, and 90 control patients who underwent conventional percutaneous transluminal coronary angioplasty (PTCA) and ICB for the treatment of in‐stent restenosis. Adjunctive coronary stenting was performed in 13 patients (29.5%) in the CBA/ICB group and 41 patients (45.6%; P < 0.001) in the PTCA/ICB group. There was no difference in the injury length or active treatment (ICB) length. The procedural and angiographic success rates were similar in both groups. There were no statistically significant differences in the incidence of death, myocardial infarction, recurrent angina pectoris, subsequent target lumen revascularization, or the composite endpoint of all four clinical outcomes (P > 0.05). Despite sound theoretical reasons why CBA may be better than conventional balloon angioplasty for treatment of in‐stent restenosis with ICB, and despite a reduction in the need for adjunctive coronary stenting, we were unable to identify differences in clinical outcome. Catheter Cardiovasc Interv 2004;63:152–157.

Coronary Artery Disease in Young Women and Men With Long-Standing Insulin-dependent Diabetes

The prevalence and predictors of coronary artery disease were examined in people aged 40 years and younger with insulin-dependent diabetes mellitus. Analysis was performed on those who presented between 1999 and 2003 for kidney and/or pancreas transplant at the University of Minnesota, as all patients who have diabetes mellitus are required to have perioperative cardiology evaluation. The mean age was 33.5 ± 4.4 years for 88 subjects, all had insulin-dependent diabetes mellitus, and 33% were dialysis dependent. Severe coronary artery disease was found in 18.2% of women and in 24.2% of men. Three-vessel coronary artery disease trended less in women (9.1%) compared with men (12.1%). Multivariate predictors for severe and 3-vessel coronary artery disease included prior coronary artery disease, hypertension duration, and ST-T wave changes on electrocardiogram. Coronary artery disease is twice as high as expected in young woman. Studies on early management for atherosclerosis are warranted in this high-risk population.

EARLY ACCESS TO CARDIAC CATHETERIZATION LABORATORY FOR PATIENTS RESUSCITATED FROM CARDIAC ARREST DUE TO A SHOCKABLE RHYTHM: THE MINNESOTA RESUSCITATION CONSORTIUM TWIN CITIES UNIFIED PROTOCOL

Background: Cardiac arrest patients that have been successfully resuscitated from shockable rhythms have a high prevalence of thrombotic and/or flow limiting coronary occlusion regardless of the presence of STEMI on the ECG. In 2012, the Minnesota Resuscitation Consortium (MRC) developed an organized approach for all those patients to gain early access to the cardiac catheterization laboratory (CCL). We report the two-year outcomes. Methods: Eleven metropolitan hospitals with 24/7 PCI capabilities agreed to provide early (within 2 hours of arrival to the emergency department) access to the CCL for all patients that were successfully resuscitated from VF/VT arrest regardless of the presence or absence of STEMI on the surface ECG. Inclusion criteria were: witnessed or un-witnessed, age >18 and Results: A total of 370 patients were resuscitated and met the inclusion criteria. Of those, 313 (85%) patients were taken to the CCL per protocol. The mean age was 55.5 years, 77% were men and 79% had witnessed arrest. Only 57 patients (15%) did not gain access to the CCL. Of the 313 patients that had early coronary angiography a total of 47% received primary angioplasty and had at least one vessel disease and 5% received coronary artery bypass. All comatose patients received therapeutic hypothermia and 35% received and implantable cardiac defibrillator. A total of 235/313 (75%) were discharged alive and of those 222/235 (94.5%) were discharged neurologically intact with a CPC of 1. Of the patients that did not gain access to the CCL, 46% (26/57) were discharged alive and of those 73% (19/26) had CPC of 1 [OR: 3.63; 2.03-6.5, p Conclusions: Over the first two years of implementation, the MRC protocol for early access to the CCL in resuscitated patients from shockable rhythm was associated with 75% survival to hospital discharge and excellent neurological outcomes in a large metropolitan area and real-life clinical practice.

Novel method for radial sheath removal using manual pressure over hemostatic pad combined with ulnar compression

Study a novel method using manual pressure on a hemostatic pad and hemoband for ulnar compression as a potential alternative for radial sheath removal.