Increasing Medical Student Interest in Nephrology.

BACKGROUND: Interest in nephrology careers is declining, possibly due to perceptions of the field and/or training aspects. Understanding practices of medical schools successfully instilling nephrology interest could inform efforts to attract leading candidates to the specialty. METHODS: The American Society of Nephrology Workforce Committee's Best Practices Project was one of several initiatives to increase nephrology career interest. Board-certified nephrologists graduating medical school between 2002 and 2009 were identified in the American Medical Association Masterfile and their medical schools ranked by production. Renal educators from the top 10 producing institutions participated in directed focus groups inquiring about key factors in creating nephrology career interest, including aspects of their renal courses, clinical rotations, research activities, and faculty interactions. Thematic content analysis of the transcripts (with inductive reasoning implementing grounded theory) was performed to identify factors contributing to their programs' success. RESULTS: The 10 schools identified were geographically representative, with similar proportions of graduates choosing internal medicine (mean 26%) as the national graduating class (26% in the 2017 residency Match). Eighteen educators from 9 of these 10 institutions participated. Four major themes were identified contributing to these schools' success: (1) nephrology faculty interaction with medical students; (2) clinical exposure to nephrology and clinical relevance of renal pathophysiology materials; (3) use of novel educational modalities; and (4) exposure, in particular early exposure, to the breadth of nephrology practice. CONCLUSION: Early and consistent exposure to a range of clinical nephrology experiences and nephrology faculty contact with medical students are important to help generate interest in the specialty.

Drug-eluting or bare-metal stents for acute myocardial infarction.

BACKGROUND: Studies comparing percutaneous coronary intervention (PCI) with drug-eluting and bare-metal coronary stents in acute myocardial infarction have been limited in size and duration. METHODS: We identified all adults undergoing PCI with stenting for acute myocardial infarction between April 1, 2003, and September 30, 2004, at any acute care, nonfederal hospital in Massachusetts with the use of a state-mandated database of PCI procedures. We performed propensity-score matching on three groups of patients: all patients with acute myocardial infarction, all those with acute myocardial infarction with ST-segment elevation, and all those with acute myocardial infarction without ST-segment elevation. Propensity-score analyses were based on clinical, procedural, hospital, and insurance information collected at the time of the index procedure. Differences in the risk of death between patients receiving drug-eluting stents and those receiving bare-metal stents were determined from vital-statistics records. RESULTS: A total of 7217 patients were treated for acute myocardial infarction (4016 with drug-eluting stents and 3201 with bare-metal stents). According to analysis of matched pairs, the 2-year, risk-adjusted mortality rates were lower for drug-eluting stents than for bare-metal stents among all patients with myocardial infarction (10.7% vs. 12.8%, P=0.02), among patients with myocardial infarction with ST-segment elevation (8.5% vs. 11.6%, P=0.008), and among patients with myocardial infarction without ST-segment elevation (12.8% vs. 15.6%, P=0.04). The 2-year, risk-adjusted rates of recurrent myocardial infarction were reduced in patients with myocardial infarction without ST-segment elevation who were treated with drug-eluting stents, and repeat revascularization rates were significantly reduced with the use of drug-eluting stents as compared with bare-metal stents in all groups. CONCLUSIONS: In patients presenting with acute myocardial infarction, treatment with drug-eluting stents is associated with decreased 2-year mortality rates and a reduction in the need for repeat revascularization procedures as compared with treatment with bare-metal stents.

Long-term clinical outcomes following drug-eluting or bare-metal stent placement in patients with severely reduced GFR: Results of the Massachusetts Data Analysis Center (Mass-DAC) State Registry.

BACKGROUND: Patients with chronic kidney disease have been under-represented in randomized trials of drug-eluting stents relative to bare-metal stents and are at high risk of mortality. STUDY DESIGN: Cohort study with propensity score matching. SETTINGS & PARTICIPANTS: All adults with chronic kidney disease and severely decreased glomerular filtration rate (GFR; serum creatinine >2.0 mg/dL or dialysis dependence) undergoing percutaneous coronary intervention with stent placement between April 1, 2003, and September 30, 2005, at all acute-care nonfederal hospitals in Massachusetts. PREDICTOR: Patients were classified as drug-eluting stent-treated if all stents were drug eluting and bare-metal stent-treated if all stents were bare metal. Patients treated with both types of stents were excluded from the primary analysis. OUTCOMES & MEASUREMENTS: 2-year crude mortality risk differences (drug-eluting - bare-metal stents) were determined from vital statistics records, and risk-adjusted mortality, myocardial infraction (MI), and revascularization differences were estimated using propensity score matching of patients with severely reduced GFR based on clinical and procedural information collected at the index admission. RESULTS: 1,749 patients with severely reduced GFR (24% dialysis dependent) were treated with drug-eluting (n = 1,256) or bare-metal stents (n = 493) during the study. Overall 2-year mortality was 32.8% (unadjusted drug-eluting stent vs bare-metal stent; 30.1% vs 39.8%; P < 0.001). After propensity score matching 431 patients with a drug-eluting stent to 431 patients with a bare-metal stent, 2-year risk-adjusted mortality, MI, and target-vessel revascularization rates were 39.4% versus 37.4% (risk difference, 2.1%; 95% CI, -4.3 to 8.5; P = 0.5), 16.0% versus 19.0% (risk difference, -3.0%; 95% CI, -8.2 to 2.1; P = 0.3), and 13.0% versus 17.6% (risk difference, -4.6%; 95% CI, -9.5 to 0.3; P = 0.06). LIMITATIONS: Observational design, ascertainment of serum creatinine level >2.0 mg/dL and dialysis dependence from case report forms. CONCLUSIONS: In patients with severely decreased GFR, treatment with drug-eluting stents was associated with a modest decrease in target-vessel revascularization not reaching statistical significance and was not associated with a difference in risk-adjusted rates of mortality or MI at 2 years compared with bare-metal stents.

Drug-eluting or bare-metal stenting in patients with diabetes mellitus: results from the Massachusetts Data Analysis Center Registry.

BACKGROUND: Patients with diabetes mellitus (DM) are at high risk for restenosis, myocardial infarction, and cardiac mortality after coronary stenting, and the long-term safety of drug-eluting stents (DES) relative to bare-metal stents (BMS) in DM is uncertain. We report on a large consecutive series of patients with DM followed up for 3 years after DES and BMS from a regional contemporary US practice with mandatory reporting. METHODS AND RESULTS: All adults with DM undergoing percutaneous coronary intervention with stenting between April 1, 2003, and September 30, 2004, at all acute care nonfederal hospitals in Massachusetts were identified from a mandatory state database. According to index admission stent type, patients were classified as DES treated if all stents were drug eluting and as BMS treated if all stents were bare metal; patients treated with both types of stents were excluded from the primary analysis. Mortality rates were obtained from vital statistics records, and myocardial infarction and revascularization rates were obtained from the state database with complete 3 years of follow-up on the entire cohort. Risk-adjusted mortality, myocardial infarction, and revascularization differences (DES-BMS) were estimated with propensity-score matching based on clinical, procedural, hospital, and insurance information collected at the index admission. DM was present in 5051 patients (29% of the population) treated with DES or BMS during the study. Patients with DM were more likely to receive DES than BMS (66.1% versus 33.9%; P<0.001). The unadjusted cumulative incidence of mortality at 3 years was 14.4% in DES versus 22.2% in BMS (P<0.001). Based on propensity-score analysis of 1:1 matched DES versus BMS patients (1476 DES:1476 BMS), the risk-adjusted mortality, MI, and target vessel revascularization rates at 3 years were 17.5% versus 20.7% (risk difference, -3.2%; 95% confidence interval, -6.0 to -0.4; P=0.02), 13.8% versus 16.9% (-3.0%; 95% confidence interval, -5.6 to 0.5; P=0.02), and 18.4% versus 23.7% (-5.4%; confidence interval, -8.3 to -2.4; P<0.001), respectively. CONCLUSIONS: In a real-world diabetic patient population with mandatory reporting and follow-up, DES were associated with reduced mortality, myocardial infarction, and revascularization rates at long-term follow-up compared with BMS.

Fibrotic injury after experimental deep vein thrombosis is determined by the mechanism of thrombogenesis.

Vessel wall matrix changes occur after injury, although this has not been well studied in the venous system. This study tested the hypothesis that the thrombus dictates the vein wall response and vein wall damage is directly related to the duration of thrombus contact. To determine the injury response over time, rats underwent inferior vena cava (IVC) ligation to produce a stasis thrombus, with harvest at various time points to 28 days (d). Significant vein wall matrix changes occurred with biomechanical injury (stiffness) peaking at 7-14 d, with concurrent early reduction in total collagen, an increase in early matrix metalloproteinase (MMP)-9 and late MMP-2, and concomitant increase in tumor necrosis factor (TNF)alpha, monocyte chemoattractant(MCP)-1 and tumor growth factor (TGF)beta (all P<0.05). To isolate the effect of the thrombus and its mechanism of genesis, rats underwent 7 d or limited stasis (24 hours), non-stasis thrombosis, or non-thrombotic IVC occlusion (Silicone plug). Vein wall stiffness was increased seven-fold, with a five-fold reduction in collagen, and 5.5- to seven-fold increase in TNFalpha, MCP-1, and TGFbeta with 7 d stasis as compared with controls (all P<0.05). By Picosirus red staining analysis, collagenolysis was significantly greater with 7 d stasis injury (P=0.01) but neither MMP-9 nor MMP-2 activity correlated with injury mechanism. In addition, vein wall cellular proliferation and uPA gene expression paralled the stasis thrombotic injury. Limited stasis, non-stasis thrombosis and non-thrombotic IVC occlusion showed a lesser inflammatory response. These data suggest both a static component and the thrombus directs vein wall injury via multiple mechanisms.

Neutrophils modulate post-thrombotic vein wall remodeling but not thrombus neovascularization.

Early deep venous thrombosis (DVT) resolution is associated with neutrophil (PMN) influx. This study examined the role of PMNs in thrombus neovascularization and vein wall injury after DVT. A rat model of DVT by inferior vena cava (IVC) ligation was performed with control serum or rabbit anti-rat PMN serum administered perioperatively with sacrifice at 2 and 7 days. At 2 days, neutropenic rats had 1.6-fold larger thrombi (P = .04) and 1.4-fold higher femoral venous pressures by water manometry (P = .008) but no difference in thrombus neovascularization was observed. By 7 days, DVT sizes were similar, but vein wall injury persisted in the neutropenic rats with a 2.0-fold increase in vein wall stiffness by microtensiometry (P < .05), as well as a 1.2-fold increased thickness (P = .04). Collagen and profibrotic growth factors were significantly increased in neutropenic IVC at 7 days (all P < .05). Vein wall and intrathrombus uPA byWestern immunoblotting, and intrathrombus MMP-9 gelatinase activity were significantly less in neutropenic rats than controls (P < .001). Conversely, MMP-2 was significantly elevated in neutropenic IVC at 2 days after DVT. However, neutropenia induced 24 hours after DVT formation resulted in no significant increase in vein wall stiffness or collagen levels at 7 days, despite 1.4-fold larger thrombi (P < .05). These data suggest a critical early role for PMN in post DVT vein wall remodeling.

Administration of adenosine receptor agonists or antagonists after controlled cortical impact in mice: effects on function and histopathology.

Adenosine is an endogenous neuroprotectant via anti-excitotoxic effects at A(1) receptors, and blood flow promoting and anti-inflammatory effects at A(2a) receptors. Previous studies showed improved motor function after fluid percussion injury (FPI) in rats treated with the broad-spectrum adenosine receptor agonist 2-chloroadenosine (2-CA). We studied the effects of 2-CA, a specific A(1) agonist (2-chloro-N(6)-cyclopentyladenosine, CCPA), and a specific A(1) antagonist (8-cyclopentyl-1,3-dipropylxanthine, DPCPX) on motor task and Morris water maze (MWM) performance, and histopathology (contusion volume, hippocampal cell counts) after controlled cortical impact (CCI) in mice. Each agent (12 nmol), or respective vehicle (saline or DMSO) was injected into dorsal hippocampus beneath the contusion immediately after CCI or craniotomy (sham). 2-CA treatment attenuated wire grip deficits after CCI (P<0.05 versus other treatments). DPCPX treatment exacerbated deficits on beam balance (P<0.05 versus sham). No treatment effect was seen on MWM performance, although there was a deleterious effect of the DMSO vehicle used for DPCPX. Contusion volume tended to be attenuated by 2-CA (P=0.08 versus saline) and increased after either DMSO or DPCPX (P<0.05 versus all groups). CA1 and CA3 counts were decreased in all groups versus sham. However, treatment with the selective A(1) agonist CCPA attenuated the CA3 cell loss (P<0.05 versus other treatment). We suggest that the beneficial effect of the broad spectrum adenosine receptor agonist 2-CA on motor function after CCI is not mediated solely by effects at the A(1) receptor.

Controlling the ABCs of diabetes in clinical practice: a community-based endocrinology practice experience.

AIMS: Determine A1C, blood pressure (BP), and total cholesterol (TC) (Diabetes ABCs) control in a community-based endocrinology practice (CBEP) and compare levels to national averages. Additionally, determine patient factors associated with ABC control. METHODS: A retrospective chart audit of 395 consecutive patients seen for diabetes management was conducted for years 2000-2004 to examine levels of control of the ABCs. Multivariate models were used to determine patient factors associated with control. RESULTS: Significantly more patients met the goal of A1C <7% in the CBEP compared to national estimates (CBEP: 47.1% vs. NHANES 1999-2000: 37%, p=0.003). Similar patterns were observed for BP (CBEP: 53.2% vs. NHANES 1999-2000: 35.8%, p<0.0001), TC (CBEP: 82% vs. NHANES 1999-2000: 48.2%, p<0.0001), and all three ABCs (CBEP: 22%, vs. NHANES 1999-2000: 7.3%, p<0.0001). The proportion of patients meeting all three ABC goals in the CBEP increased significantly over time (p<0.0001). Multivariate models demonstrated that patients not needing insulin (p<0.0001), and taking fewer BP (p<0.0001), and cholesterol-lowering medications (p<0.02) were significantly more likely to have ABCs in control. CONCLUSIONS: Attainment of ABC goals is feasible in a CBEP and can be achieved at rates higher than national averages. Attention to factors that affect these goals is warranted.

Vein wall remodeling after deep vein thrombosis involves matrix metalloproteinases and late fibrosis in a mouse model.

HYPOTHESIS: Deep venous thrombosis (DVT) confers vein wall injury associated with fibrosis and extracellular matrix (ECM) turnover, likely mediated by matrix proteases. This study investigated the expression of proteases and collagen involved in early vein wall remodeling. METHODS: In the mouse, DVT was produced by ligation of the infrarenal inferior vena cava (IVC) or sham operation, and tissue was harvested at 4, 8, and 12 days. The vein wall tissue was processed for real-time reverse transcriptase-polymerase chain reaction (6 to 8 per time point), Western immunoblotting (5 per time point), and gelatin zymography (5 per time point). Analysis of variance was used for multiple comparisons, and a P < .05 was significant. RESULTS: Thrombus resolution was documented by a 38% decrease in the thrombosed IVC weight from day 4 to day 12 (P = .007). Total vein wall collagen increased over time, with a corresponding increase in procollagen I and III, and expression peaked at 12 days (24-fold and 6.1-fold, respectively, P < .02). Matrix metalloproteinase-2 (MMP-2) gene expression was 23-fold greater at 12 days after thrombus formation compared with sham or 4 days after thrombosis (P < .05). Total MMP-2 activity was also significantly elevated at 12 days compared with sham (P < .05). MMP-9 expression was 19-fold and 27-fold higher at days 4 and 8, respectively, relative to sham (P < .05), with no difference in activity. MMP-14 expression was twofold to 3.6-fold greater at day 12 compared with earlier time points and shams (P < .001), but no differences in protein levels were found. Urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1) protein levels were not significantly different from sham over time; however, the ratio of uPA to PAI-1 was decreased through 8 days. CONCLUSIONS: Vein wall remodeling after DVT is similar to wound healing and is associated with increased procollagen gene expression and total collagen. It is also associated with increased early MMP-9 expression, followed by MMP-2 expression and activity after DVT resolution. CLINICAL RELEVANCE: Deep vein thrombosis is an often neglected problem that long term is associated with the postphlebitic syndrome of limb swelling, pain, and often ulceration. The basic mechanisms of the vein wall damage that results have not been delineated. The following study describes the vein wall matrix metalloproteinase gene and activity response induced over time in the vein wall after DVT. Additionally, the corresponding collagen upregulation and proximate plasmin system mediators are determined. With this knowledge, potential therapies to reduce vein wall injury directly might be possible.

Neutropenia impairs venous thrombosis resolution in the rat.

OBJECTIVES: Neutrophil influx is one of the first events in a formed deep venous thrombosis (DVT), but whether these cells are active participants in the resolution process is not clear. This study tests the hypothesis that neutrophils (PMN) are active participants in DVT resolution. METHODS: Thrombosis was induced by inferior vena caval (IVC) ligation in male Sprague-Dawley rats, and rats were sacrificed at 2, 4, or 7 days for evaluation of the thrombus. Neutropenia was induced by rabbit anti-rat PMN serum, and controls received rabbit serum. Venography was performed at the 7-day time point. Immunohistochemical staining was performed to quantify intrathrombus PMNs and monocytes, and the myeloperoxidase (MPO) assay was performed to assess intrathrombus neutrophil activity. Intrathrombus concentrations of kerotinocyte cytokine (KC), macrophage inflammatory protein-2 (MIP-2), gamma interferon inducible protein-10 (IP-10), macrophage inflammatory protein-1 alpha (MIP-1 alpha), monocyte chemoattractant protein-1 (MCP-1), and tumor necrosis factor (TNF)-alpha were quantified by enzyme immunoassay at each time point and normalized to total protein. Total collagen was determined at day 7. RESULTS: Peripheral blood smears showed a 94% PMN reduction at 2 days (P <.05), recovering to 44% of control at 7 days. Intrathrombus PMNs were significantly lower in neutropenic rats at 2 and 4 days, but there were no differences in intrathrombus monocytes. The MPO assay confirmed reduced neutrophil activity at 4 days. Thrombi from neutropenic rats were larger at 2 and 7 days compared with controls. In vivo thrombus area at 7 days as assessed by venography was also greater in neutropenic rats as compared with controls. The intrathrombus KC concentration was increased more than 20-fold in the neutropenic rats at 2 days, but there were no significant differences in other intrathrombus chemokines. Finally, intrathrombus collagen was increased over threefold in neutropenic rats as compared with controls. CONCLUSION: Neutropenia impairs DVT resolution by several measures, most likely by altering normal fibrinolytic activity and thrombus collagen turnover.

Deep vein thrombosis resolution is not accelerated with increased neovascularization.

INTRODUCTION: Deep venous thrombosis (DVT) resolution involves fibrinolysis, neovascularization, and fibrosis. We hypothesized that promoting neovascularization would accelerate DVT resolution. METHODS: A rat model of stasis DVT was produced with proximal ligation of the inferior vena cava (IVC) and all visible tributaries. One microg of interferon inducible protein (IP-10; angiostatic chemokine), basic fibroblast growth factor (bFGF; pro-angiogenic cytokine), epithelial neutrophil activating protein (ENA-78; pro-angiogenic chemokine), or saline solution control was injected into the IVC after ligation, and then via tail vein injection daily until sacrifice at either 4 or 8 days. Peripheral blood counts were measured, and thrombus weight was recorded at sacrifice. Laser Doppler in vivo imaging was used to estimate post-thrombotic IVC blood flow. Immunohistologic assessment of the thrombosed IVC for polymorphonuclear neutrophils (PMNs), monocytes (ED-1), and laminin (neovascular channels) was performed or the thrombus was separated from the IVC and assayed for keratinocyte cytokine (KC), monocyte chemotactic protein-1 (MCP-1), bFGF with enzyme-linked immunosorbent assay (ELISA), and total collagen with a direct colorimetric assay. RESULTS: Peripheral blood and intrathrombus PMNs and monocytes were not significantly different in the treated or control rats. There were no differences in any measure at 4 days. At 8 days, thrombus neovascularity, but not weight or collagen content, was increased in rats treated with bFGF or ENA-78 compared with control rats (17.6 +/- 0.93, 16.2 +/- 0.97 vs 13.2 +/- 0.79; channels/5 high-power fields (hpf; n = 6-10; P <.05). Post DVT IVC blood flow was significantly increased in bFGF-treated rats but not in rats treated with IP-10 or ENA-78, as compared with control rats. Rats treated with ENA-78 had increased intrathrombus bFGF compared with control rats (85 +/- 27 pg/mg protein vs 20 +/- 6 pg/mg protein; n = 6; P <.05), but other mediators were not significantly different in treated rats compared with control rats. CONCLUSION: Pro-angiogenic compounds increase thrombus neovascularization, but this does not correlate with smaller or less fibrotic DVT. Mechanisms other than neovascularization may be more important to hasten DVT dissolution. Clinical relevance Improved therapy for deep venous thrombosis (DVT) will ideally increase the rate of thrombus dissolution and eliminate the bleeding risks of anticoagulation. This study evaluated promoting DVT neovascularization with angiogenic chemokines, and, while successful by experimental measures, this did not translate into smaller DVT. Solely promoting thrombus neovascularization will not likely speed resolution.