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While there has been growing research that explores the impact of race- and cultural-specific student organizations or spaces on Black students and particularly Black males (Dancy, 2011; Harper & Quaye, 2007; McClure, 2006; Museus, 2008; L. Patton, 2006), there have been fewer studies (Ellis, 2009) examining emerging, institutionalized Black male initiative programs designed and administered by higher education professionals. Institutionalized Black male leadership programs (BMLPs) born out of such initiatives provide Black male students, particularly those that attend predominantly White institutions (PWIs), with services uniquely designed to respond to the specific needs of Black males. These institutionalized BMLPs present opportunities for administrators to develop experiences based on theory, research, and practice (i.e., everyday occurrences) (Harper & Kuykendall, 2012). This study advances the body of literature on student-led leadership programs by examining the impact of an institutionalized Black male leadership program on Black college male persistence and engagement. We conducted focus group interviews among eight Black males participating in an institutionalized BMLP at a large, PWI in the southern region of the United States. Forming connections within the BMLP and identifying connections between race, gender, and engagement were two of the primary findings uncovered during the investigation. Findings suggest that institutions can successfully form BMLPs that serve a critical role, similar to same-race organizations, in linking Black male students to academic and social campus communities while facilitating cultural connections (e.g., connections with ethnic minority faculty and staff). (Contains 1 note.)

Background: Surgical practice patterns in operative treatment of carpometacarpal (CMC-1) osteoarthritis (OA) have been evaluated in the USA repeatedly. This study evaluates the current surgical patterns in the treatment of isolated CMC-1 OA among hand surgeons in Europe. Methods: An online survey was distributed to hand surgeons of participating member states of the Federation of European Societies for Surgery of the Hand (FESSH). Information regarding country of practice, years of experience and surgical treatment of choice was collected. Statistical analyses of correlations between demographics and treatment preferences were done using chi-squared testing. Results: A total of 444 replies were recorded. Trapeziectomy with ligament reconstruction and tendon interposition (LRTI) was opted by 46% of the respondents as a procedure of first choice, followed by prosthetic joint replacement (25%) and trapeziectomy with interpositional arthroplasty (23%). Among surgeons practicing in the Netherlands, 35% mentioned trapeziectomy without any complementary procedures as a surgical treatment of first choice. Prosthetic joint replacement is chosen by respectively 96% and 72% of the respondents in Belgium and France as a preferred surgical procedure. Conclusions: This European-wide study provides insight in the prevailing surgical management for isolated CMC-1 OA. Trapeziectomy with LRTI is the most popular procedure among the participating hand surgeons in Europe. Geographical trends seem to play an important role in the choice of preferred technique. Factors influencing the decision-making among surgeons practicing in different countries should be explored more closely in future studies. Level of evidence: Level IV, prognostic study. [ABSTRACT FROM AUTHOR]

While there has been growing research that explores the impact of race- and cultural-specific student organizations or spaces on Black students and particularly Black males (Dancy, 2011; Harper & Quaye, 2007; McClure, 2006; Museus, 2008; L. Patton, 2006), there have been fewer studies (Ellis, 2009) examining emerging, institutionalized Black male initiative programs designed and administered by higher education professionals. Institutionalized Black male leadership programs (BMLPs) born out of such initiatives provide Black male students, particularly those that attend predominantly White institutions (PWls), with services uniquely designed to respond to the specific needs of Black males. These institutionalized BMLPs present opportunities for administrators to develop experiences based on theory, research, and practice (i.e., everyday occurrences) (Harper & Kuykendall, 2012). This study advances the body of literature on student-led leadership programs by examining the impact of an institutionalized Black male leadership program on Black college male persistence and engagement. We conducted focus group interviews among eight Black males participating in an institutionalized BMLP at a large, PWl in the southern region of the United States. Forming connections within the BMLP and identifying connections between race, gender, and engagement were two of the primary findings uncovered during the investigation. Findings suggest that institutions can successfully form BMLPs that serve a critical role, similar to same-race organizations, in linking Black male students to academic and social campus communities while facilitating cultural connections (e.g., connections with ethnic minority faculty and staff). [ABSTRACT FROM AUTHOR]

Abstract: During its long history of developing and deploying remote sensing instruments, NASA has provided scientific data that have benefitted a variety of scientific applications among them archaeology. Multispectral and hyperspectral instruments mounted on orbiting and sub-orbital platforms have provided new and important information for the discovery, delineation and analysis of archaeological sites worldwide. Since the early 1970s, several of the ten NASA centers have collaborated with archaeologists to refine and validate the use of active and passive remote sensing for archaeological use. The Stennis Space Center (SSC), located in Mississippi USA has been the NASA leader in archaeological research. Together with colleagues from Goddard Space Flight Center (GSFC), Marshall Space Flight Center (MSFC), and the Jet Propulsion Laboratory (JPL), SSC scientists have provided the archaeological community with useful images and sophisticated processing that have pushed the technological frontiers of archaeological research and applications. Successful projects include identifying prehistoric roads in Chaco canyon, identifying sites from the Lewis and Clark Corps of Discovery exploration, and assessing prehistoric settlement patterns in southeast Louisiana. The Scientific Data Purchase (SDP) stimulated commercial companies to collect archaeological data. At present, NASA formally solicits “space archaeology” proposals through its Earth Science Directorate and continues to assist archaeologists and cultural resource managers in doing their work more efficiently and effectively. This paper focuses on passive remote sensing and does not consider the significant contributions made by NASA active sensors. Hyperspectral data offers new opportunities for future archaeological discoveries. [Copyright &y& Elsevier]

We study the impact of seasonal adjustment on the properties of business cycle expansion and recession regimes using analytical, simulation and empirical methods. Analytically, we show that the X-11 adjustment filter both reduces the magnitude of change at turning points and reduces the depth of recessions, with specific effects depending on the length of the recession. A Monte Carlo analysis using Markov-switching models confirms these properties, with particularly undesirable effects in delaying the recognition of the end of a recession. However, seasonal adjustment can help to clarify the true regime when this is well underway. These results continue to hold when a seasonally non-stationary process with regime-dependent mean is misspecified as one with deterministic seasonal effects. The empirical findings, based on four coincident US business cycle indicators, reinforce the analytical and simulation results by showing that seasonal adjustment leads to the identification of longer and shallower recessions than obtained using unadjusted data. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The article assesses the prognostic value of the post-exercise ankle-brachial index (ABI) in detecting peripheral arterial disease in the U.S. The use of the ABI are simple, inexpensive and noninvasive and can be performed to patients. The study reveals that resting and post-exercise ABI values are independently associated with late overall mortality and cardiac death.

A wealth of new data provides a well-constrained chronology of mid- to late Holocene coastal development in the Louisiana–Mississippi borderland that may also be utilized in a globally applicable sedimentation model. Barrier sand and deltaic mud sequences illustrate a process by which potential ground water and hydrocarbon reservoir rocks accumulated unusually rapidly and were preserved. Set against decelerating Holocene sea-level rise and locally variable subsidence rates, the study provides an example of the interplay between an emerging, prograding, and partially stranded barrier island chain, a sizable estuary, and several extensive delta lobes. Utilizing microfossil fauna-based depositional facies information and archaeological data, absolute dates helped to reconstruct the history of the Alabama–Louisiana barrier chain and deltas between ca. 5.7 and ca. 1.5 14C ka BP. Protected by the substantial dune cover that prevented island submersion, the regional eustastic transgression paradoxically was synchronous with significant progradational barrier and deltaic regression. The earliest barrier islands emerged ca. 4.6–4.4 14C ka BP (ca. 5.7–5.0 cal years) when sea level stood at ca. -1.0 to -1.5 m. These islands isolated Mississippi Sound from the greater Gulf of Mexico. The absence of a lagoonal-inshore sediment interval beneath the islands and the 3–15 m thick basal nearshore marine muddy–sandy unit that blankets the Pleistocene surface refutes the transgressive history of barrier initiation. The islands aggraded on a 3.0–16.5 m thick fine sandy shallow-marine regressive platform lithosome that, in turn, overlies a transgressive muddy–sandy nearshore marine lower sediment interval.Avulsion of the Mississippi River had abruptly reduced nearshore salinities by ca. 3.9–3.7 ka 14C BP. Renewed Mississippi delta growth induced rapid aggradation and progradation on the opposite Pearl River delta-mainland shore as well. Gulf influences have rapidly diminished in areas so affected. A new absolute chronology of the Mississippi–St. Bernard delta lobes constrains these events. Delta growth and mainland progradation first isolated, then severely constricted the Lake Borgne embayment. Accompanied by ongoing subsidence, the western barriers were stranded, then buried. Shoaling, related to St. Bernard delta progradation, interfered with westward littoral drift to maintain Cat Island. Archaeology provided important supplementary data for dating environmental changes. Refuting earlier suggestions that Native colonization rapidly followed delta complex formation, the earliest known Indian sites postdated the start of the associated St. Bernard delta lobe by 1.9–3.1 14C ka. [Copyright &y& Elsevier]

Background: Chronic mesenteric ischemia (CMI) is the result of insufficient blood supply to the gastrointestinal tract and is caused by atherosclerotic stenosis of one or more mesenteric arteries in > 90% of cases. Revascularization therapy is indicated in patients with a diagnosis of atherosclerotic CMI to relieve symptoms and to prevent acute-on-chronic mesenteric ischemia, which is associated with high morbidity and mortality. Endovascular therapy has rapidly evolved and has replaced surgery as the first choice of treatment in CMI. Bare-metal stents (BMS) are standard care currently, although retrospective studies suggested significantly higher patency rates for covered stents (CS). The Covered stents versus Bare-metal stents in chronic atherosclerotic Gastrointestinal Ischemia (CoBaGI) trial is designed to prospectively assess the patency of CS versus BMS in patients with atherosclerotic CMI.Methods/design: The CoBaGI trial is a randomized controlled, parallel-group, patient- and investigator-blinded, superiority, multicenter trial conducted in six centers of the Dutch Mesenteric Ischemia Study group (DMIS). Eighty-four patients with a consensus diagnosis of atherosclerotic CMI are 1:1 randomized to either a balloon-expandable BMS (Palmaz Blue with rapid-exchange delivery system, Cordis Corporation, Bridgewater, NJ, USA) or a balloon-expandable CS (Advanta V12 over-the-wire, Atrium Maquet Getinge Group, Hudson, NH, USA). The primary endpoint is the primary stent-patency rate at 24 months assessed with CT angiography. Secondary endpoints are primary stent patency at 6 and 12 months and secondary patency rates, freedom from restenosis, freedom from symptom recurrence, freedom from re-intervention, quality of life according the EQ-5D-5 L and SF-36 and cost-effectiveness at 6, 12 and 24 months.Discussion: The CoBaGI trial is designed to assess the patency rates of CS versus BMS in patients treated for CMI caused by atherosclerotic mesenteric stenosis. Furthermore, the CoBaGI trial should provide insights in the quality of life of these patients before and after stenting and its cost-effectiveness. The CoBaGI trial is the first randomized controlled trial performed in CMI caused by atherosclerotic mesenteric artery stenosis.Trial Registration: ClinicalTrials.gov, ID: NCT02428582 . Registered on 29 April 2015. [ABSTRACT FROM AUTHOR]

• Collection efficiency estimates are necessary for accurate emissions modeling. • Measured collection efficiency data categorized and compared with current defaults. • Cover type was statistically significant indicator of collection efficiency. • Results: 41% efficiency for daily cover, 69 % for intermediate, and 71 % for final. • New defaults greatly reduce discrepancy between modeled and measured estimates. Landfill methane emissions are commonly estimated using cover-type dependent default collection efficiency values, with a first-order decay model or measured gas collection. Current default collection efficiencies used in the United States were predominately derived from 4 studies conducted during or prior to 2007 that relied on flux chambers. Flux chambers are limited by small sample sizes, placement restrictions, and the inability to measure emissions from gas or leachate collection systems. Since 2007, over 14 new studies have been completed using more advanced technologies that allow for direct measurement of methane plumes from most or all of a landfill's surface. On average, these measurements are 2–3 times greater than emissions predicted by current models and collection efficiency defaults. In lieu of measuring emissions from all landfills, updating collection efficiency defaults can bring modeled emissions into better alignment with measurements. To this end, collection efficiency estimates derived from measured data were categorized into cover types and then adjusted to account for cases where whole plume measurement was an amalgamation of multiple cover types. The resultant adjusted default values were 41% for daily cover, 69% for intermediate cover, and 71% for final cover. Direct measurement of landfill methane emissions is preferrable to account for the full range of variables driving landfill emissions, including collection system design and operation. However, applying these updated defaults back into the landfill emission models eliminates underprediction of landfill emissions for the dataset reviewed, and would provide a more accurate estimate of landfill gas emissions where measurements are unavailable. [ABSTRACT FROM AUTHOR]

Analysis of data from the US Environmental Protection Agency (EPA) on municipal solid waste (MSW) generation rates correlated to personal consumption expenditure (PCE) uncovers a decoupling event occurring between 1997 and 2000. A comparison of waste generation rates for each material category found in MSW reveals that plastics increased by nearly 84 times from 1960 to 2013 while total MSW increased only 2.9 times. The increase in plastic waste generation coincides with a decrease in glass and metal found in the MSW stream. In addition, calculating the material substitution rates for glass, metal and other materials with plastics in packaging and containers demonstrates an overall reduction by weight and by volume in MSW generation of approximately 58% over the same time period. A quantitative calculation of a scenario where plastics were not used in packaging and containers to replace glass, metal, and other materials demonstrates that MSW generation rate rises equally with PCE. Therefore, this study has determined that the increase of plastic use is a contributing factor to the decoupling of MSW generation from PCE. [ABSTRACT FROM AUTHOR]

Background: Current guidelines for locally advanced stage 2/3 rectal cancer recommend neoadjuvant chemoradiotherapy followed by total mesorectal excision and adjuvant chemotherapy. The oncologic benefit of adjuvant chemotherapy has not been consistently demonstrated., Objective: The purpose of this study was to evaluate disease recurrence and survival in patients with rectal cancer who received adjuvant chemotherapy after chemoradiotherapy and total mesorectal excision., Design: This was a retrospective review of patients with stage 2/3 rectal cancer after chemoradiotherapy and surgery, based on receipt of adjuvant chemotherapy., Settings: The study was conducted at the Kaiser Permanente Southern California system of 14 hospitals and associated clinics., Patients: A total of 862 patients with stage 2/3 rectal cancer diagnosed and treated between January 1, 2005, and December 31, 2016, were included in this study., Interventions: The study involved neoadjuvant chemoradiotherapy followed by total mesorectal excision with or without adjuvant chemotherapy., Main Outcome Measures: The primary end point was recurrence-free survival., Results: A total of 348 stage 2 and 514 stage 3 patients were included; 660 patients (76.6%) underwent adjuvant chemotherapy. Mean patient follow-up after surgery was 63.0 months (range, 3-160). Multivariable analysis showed that yp stage (HR for yp stage 2 = 4.74; yp stage 3 = 8.83) and en bloc resection (HR = 1.76) were the only variables that significantly predicted disease recurrence. Neither pretreatment tumor stage nor receipt of adjuvant chemotherapy was significantly associated with recurrence-free survival. Log-rank testing failed to demonstrate significant recurrence-free survival improvement after receipt of adjuvant chemotherapy in any patient subgroup., Limitations: The study was limited by selection bias attributed to the nature of a retrospective study without patient randomization or predefined treatment protocol., Conclusions: In stage 2/3 rectal cancer treated with chemoradiotherapy and surgery, the addition of adjuvant chemotherapy was not associated with decreased recurrence-free survival in the entire cohort or in any subgroup, whereas tumor response to chemoradiotherapy is closely associated with disease recurrence. These findings have important consequences for treatment and surveillance decisions for patients with rectal cancer. Presurgical efforts that maximize tumor downstaging, such as total neoadjuvant therapy, may produce better oncologic outcomes than traditional adjuvant chemotherapy. See Video Abstract at http://links.lww.com/DCR/B134. LA QUIMIOTERAPIA ADYUVANTE NO MEJORA LA SOBREVIDA LIBRE DE RECURRENCIA EN PACIENTES CON CÁNCER DE RECTO ESTADÍOS II O III DESPUÉS DE RADIO-QUIMIOTERAPIA NEOADYUVANTE Y ESCISIÓN TOTAL DEL MESORRECTO: Las guías actuales para el tratamiento de cáncer rectal en estadio II-III localmente avanzado, recomiendan la radio-quimioterapia neoadyuvante con escisión total del mesorrecto seguidas de quimioterapia adyuvante. El beneficio oncológico de la quimioterapia adyuvante no ha sido demostrado de manera fehaciente.Evaluar la recurrencia y sobrevida a la enfermedad en pacientes con cáncer rectal que recibieron quimioterapia adyuvante después de radio-quimioterapia y escisión total del mesorrecto.Revisión retrospectiva de pacientes con cáncer rectal en estadios II-III después de radio-quimioterapia y cirugía, basada en la recepción de quimioterapia adyuvante.Sistema Permanente de Kaiser Sur-Californiano de 14 hospitales y clínicas asociadas.862 pacientes con cáncer rectal en estadio II-III diagnosticados y tratados entre el 1 de Enero 2005 y el 31 de Diciembre 2016.Radio-quimioterapia neoadyuvante seguida de escisión total del mesorrecto +/- quimioterapia adyuvante.El objetivo primario fue la sobrevida libre de recurrencia.Fueron incluidos 348 pacientes en estadio II y 514 en estadio III. 660 pacientes (76,6%) se sometieron a quimioterapia adyuvante. El seguimiento medio de cada paciente después de la cirugía fué de 63.0 meses (rango, 3-160). El análisis multivariable mostró que la etapa yp (Cociente de riesgo para estadío yp II = 4.74 y estadío yp III = 8.83) y la resección en bloque (Cociente de riesgo = 1.76) fueron las únicas variables que predijeron significativamente la recurrencia de la enfermedad. Ni el estadío tumoral previo al tratamiento ni la recepción de quimioterapia adyuvante se asociaron significativamente con la sobrevida libre de recurrencia. Las pruebas de rango logarítmico no pudieron demostrar una mejoría significativa de la sobrevida libre de recurrencia después de recibir quimioterapia adyuvante en cualquier subgrupo de pacientes.Sesgo de selección, debido al estudio retrospectivo sin aleatorización de los pacientes o protocolo de tratamiento predefinido.En casos de cáncer de recto estadíos II-III tratados con radio-quimioterapia y cirugía, la adición de quimioterapia adyuvante no se asoció con una disminución de la sobrevida libre de recurrencia en toda la cohorte o en ningún subgrupo, mientras que la respuesta tumoral a la radio-quimioterapia está estrechamente asociada con la recurrencia de la enfermedad. Estos hallazgos tienen consecuencias importantes en la decisión del tratamiento y la vigilancia en pacientes con cáncer de recto. Los esfuerzos pre-quirúrgicos que maximizan la reducción del tamaño del tumor, como la terapia neoadyuvante total, pueden producir mejores resultados oncológicos que la quimioterapia adyuvante tradicional. Consulte Video Resumen en http://links.lww.com/DCR/B134.

Background & Aims: European guidelines recommend different surveillance intervals of non-dysplastic Barrett's esophagus (NDBE) based on segment length, as opposed to guidelines in the United States, which do recommend surveillance intervals based on BE length. We studied rates of progression of NDBE to high-grade dysplasia (HGD) or esophageal adenocarcinoma (EAC) in patients with short-segment BE using the definition of BE in the latest guidelines (length ≥1 cm)., Methods: We collected demographic, clinical, endoscopy, and histopathology data from 1883 patients with endoscopic evidence of NDBE (mean age, 57.3 years; 83.5% male; 88.1% Caucasians) seen at 7 tertiary referral centers. Patients were followed for a median 6.4 years. Cases of dysplasia or EAC detected within 1 year of index endoscopy were considered prevalent and were excluded. Unadjusted rates of progression to HGD or EAC were compared between patients with short (≥1 and <3) and long (≥3) BE lengths using log-rank tests. A subgroup analysis was performed on patients with a documented Prague C&M classification. We used a multivariable proportional hazards model to evaluate the association between BE length and progression. Adjusted hazards ratios were calculated after adjusting for variables associated with progression., Results: We found 822 patients to have a short-segment BE (SSBE) and 1061 to have long segment BE (LSBE). We found patients with SSBE to have a significantly lower annual rate of progression to EAC (0.07%) than of patients with LSBE (0.25%) (P = .001). For the combined endpoint of HGD or EAC, annual progression rates were significantly lower among patients with SSBE (0.29%) compared to compared to LSBE (0.91%) (P < .001). This effect persisted in multivariable analysis (hazard ratio, 0.32; 95% CI, 0.18-0.57; P < .001)., Conclusion: We analyzed progression of BE (length ≥1 cm) to HGD or EAC in a large cohort of patients seen at multiple centers and followed for a median 6.4 years. We found a lower annual rate of progression of SSBE to EAC (0.07%/year) than of LSBE (0.25%/year). We propose lengthening current surveillance intervals for patients with SSBE., (Copyright © 2019 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Purpose: To determine the impact of expectant management surveillance for patients at risk for squamous cell carcinoma of the anus (SCCA)., Methods: Adult patients at risk for anal cancer, specifically those with human immunodeficiency virus (HIV) or known human papilloma virus (HPV) infections (anal dysplasia, anogenital warts, cervical dysplasia, or cervical cancer), underwent expectant management surveillance with targeted therapy of only grossly abnormal or symptomatic anoderm lesions. A retrospective analysis investigated the SCCA incidence in these surveilled populations and in the general population patients without known HIV or HPV infection., Results: There were 452 incident SCCA in a population of 5,978,510 patients (mean follow-up per patient of 5.4 years). Four hundred ten cancers (90.7%) developed in 5,750,501 HIV-negative patients without documented history of HPV infection (cumulative incidence 0.007%). In at-risk patient populations, the cumulative incidence was 0.69% in patients with anal dysplasia (6 out of 872 patients), 0.14% in HIV+ patients (8 out of 5626 patients), and less than 0.1% in the remaining at-risk groups: cervical cancer (1 out of 1168 patients), cervical dysplasia (14 out of 125,604 patients), and genital warts (14 out of 94,739 patients)., Conclusions: Expectant management surveillance, with targeted treatment for symptomatic or abnormal lesions, is an effective strategy for the diagnosis of anal cancer in at-risk patient populations. In this study, most patients who developed anal cancer had no known risk factors. A screening strategy for the general population needs to be further delineated.

The study was designed to determine the effect of joystick handle size and (display-control) gain at two levels of required task precision on performance and physical load on crane operators. Eight experienced crane operators performed a simulated crane operation task on a computer by use of a joystick with either a short or a large handle. The task was performed at three gain levels and at two levels of required precision. Task performance, wrist and forearm postures, upper extremity muscle activity, perceived exertion and perceived comfort were measured.Task performance improved when using the joystick with the short handle and when working at a higher gain, while physical load decreased or remained the same. An increased level of required task precision was associated with a lower performance, but physical load was not affected. External validity of the simulated crane task seemed sufficient enough to extrapolate the results to practice.A joystick with a short handle is recommended, as this leads to an increased performance whilst the operator's physical load decreases or remains the same. Further optimization of performance and physical load can be achieved by optimizing gain settings of the joystick in relation to the task and type of joystick used.

At 12 centers, 395 patients, including 288 men (73%) and 107 women (27%) with acute myocardial infarction (AMI), were prospectively randomized to treatment with tissue plasminogen activator (t-PA) or primary percutaneous transluminal coronary angioplasty (PTCA). Compared with men, women were older (65.7 vs 57.7 years, p < 0.0001), more often had diabetes mellitus (19% vs 10%, p = 0.03), systemic hypertension (54% vs 39%, p = 0.005), prior congestive heart failure (5% vs 0%, p = 0.002), and presented later after symptom onset (229 vs 174 minutes, p = 0.0004). The in-hospital mortality in women was 3.3-fold higher than men (9.3% vs 2.8%, p = 0.005). After adjustment for comorbid baseline characteristics, however, only advanced age independently correlated with mortality. Among t-PA-treated patients, mortality was significantly higher in women than in men (14.0% vs 3.5%, p = 0.006). Intracranial hemorrhage after t-PA was also more common in women than in men (5.3% vs 0.7%, p = 0.037). In contrast, women and men had similar in-hospital mortality after primary PTCA (4.0% vs 2.1%, respectively, p = 0.46). No intracranial bleeding occurred in PTCA-treated patients. A univariate trend was present for reduced in-hospital mortality in women treated with PTCA rather than t-PA (4.0% vs 14.0%, p = 0.07). By multiple logistic regression analysis of 15 clinical variables, treatment with PTCA rather than t-PA, as well as younger age, were independently predictive of in-hospital survival in women.(ABSTRACT TRUNCATED AT 250 WORDS)

Objectives: The safety and long-term results of directional coronary atherectomy in stented coronary arteries were determined. In addition, tissue studies were performed to characterize the development of restenosis., Methods: Directional coronary atherectomy was performed in restenosed stents in nine patients (10 procedures) 82 to 1,179 days after stenting. The tissue was assessed for histologic features of restenosis, smooth muscle cell phenotype, markers of cell proliferation and cell density. A control (no stenting) group consisted of 13 patients treated with directional coronary atherectomy for restenosis 14 to 597 days after coronary angioplasty, directional coronary atherectomy or laser intervention., Results: Directional coronary atherectomy procedures within the stent were technically successful with results similar to those of the initial stenting procedure (2.31 +/- 0.38 vs. 2.44 +/- 0.35 mm). Of five patients with angiographic follow-up, three had restenosis requiring reintervention (surgery in two and repeat atherectomy followed by laser angioplasty in one). Intimal hyperplasia was identified in 80% of specimens after stenting and in 77% after coronary angioplasty or atherectomy. In three patients with stenting, 70% to 76% of the intimal cells showed morphologic features of a contractile phenotype by electron microscopy 47 to 185 days after coronary intervention. Evidence of ongoing proliferation (proliferating cell nuclear antigen antibody studies) was absent in all specimens studied. Although wide individual variability was present in the maximal cell density of the intimal hyperplasia, there was a trend toward a reduction in cell density over time., Conclusions: Although atherectomy is feasible for the treatment of restenosis in stented coronary arteries and initial results are excellent, recurrence of restenosis is common. Intimal hyperplasia is a nonspecific response to injury regardless of the device used and accounts for about 80% of cases of restenosis. Smooth muscle cell proliferation and phenotypic modulation toward a contractile phenotype are early events and largely completed by the time of clinical presentation of restenosis. Restenotic lesions may be predominantly cellular, matrix or a combination at a particular time after a coronary procedure.