Deformational Plagiocephaly and Reduced Cervical Range of Motion: A Pediatric Case Series in a Chiropractic Clinic.

CONTEXT: Deformational plagiocephaly, a non-synostotic asymmetry of the occipital bone, is a frequent occurrence in infants, with a peak incidence of 19.7% at 4 months of age. One aetiology is hypothesized to be due to restriction in normal cervical spine motion. OBJECTIVE: This study aimed to determine if an association exists between plagiocephaly and restrictions in the passive range of motion (PROM) of the cervical spine. METHODS: A retrospective analysis of the clinical records of 150 consecutive cases was performed, with specific inclusion/exclusion criteria applied. Data were collated and analysed. SETTING: Private chiropractic practice, Victoria, Australia. PARTICIPANTS: Participants were 150 infants under 12 months of age, with a mean age of 122 ± 60.6 days and a range in age of 42 to 245 days. OUTCOME MEASURES: The outcome included measurement of the cervical PROM, identification of the location of the restriction, and a decision about the presence of plagiocephaly. RESULTS: In the 150 cases, 78.7% were found to have restrictions in cervical PROM, with 60.2% showing an indication of plagiocephaly. In the cases with plagiocephaly, 92.2% were found to have restrictions in cervical PROM. CONCLUSION: The presence of plagiocephaly was associated with a higher prevalence of restriction in cervical PROM. A statistically significant association existed between restriction of the occipitoatlantal joint and development of contralateral deformational plagiocephaly. Future clinical trials assessing the effectiveness of spinal manipulative therapy in the treatment and management of restricted cervical PROM and plagiocephaly in infants are needed.

Primary healthcare needs and barriers to care among Calgary's homeless populations.

BACKGROUND: Despite Canada's universal healthcare system, significant barriers impede individuals experiencing homelessness from accessing health services. Furthermore, there is a paucity in the qualitative literature describing how Canadians experiencing homelessness access health care services. Our objective was to qualitatively explore perceived healthcare needs and barriers among individuals experiencing homelessness in one large Canadian city - Calgary, Alberta. METHODS: We conducted a qualitative descriptive study that included open-ended interviews and focus groups with a variety of stakeholders who are involved in healthcare among Calgary's homeless populations. These included individuals experiencing homelessness (n = 11) as well as employees from several healthcare service providers for those experiencing homelessness (n = 11). Transcripts from these interviews were thematically analyzed by two analysts. RESULTS: Stakeholder interviews yielded several pervasive themes surrounding the health care needs of the homeless and barriers to accessing care. Some of the primary health care needs which were identified included mental health, addictions, and allied health as well as care that addresses the social determinants of health. Notably, it was difficult for many stakeholders to pinpoint specific health care priorities, as they identified that the health care needs among Calgary's homeless populations are diverse and complex, often even describing the needs as overwhelming. Types of barriers to primary care that were identified by stakeholders included: emotional, educational, geographical, financial and structural barriers, as well as discrimination. CONCLUSIONS: Our findings highlight the diverse primary health care needs of Calgary's homeless populations. Despite the fact that Canada has a universal publicly funded health care system, individuals experiencing homelessness face significant barriers in accessing primary care.

Effect of Temperature and Host Life Stage on Efficacy of Soil Entomopathogens Against the Swede Midge (Diptera: Cecidomyiidae).

The Swede midge, Contarinia nasturtii Kieffer, is an economically significant pest of cruciferous crops in Canada and the northeastern United States. The effect of temperature on the virulence of three entomopathogenic nematode species, Heterorhabditis bacteriophora, Steinernema carpocapsae, and Steinernema feltiae, the entomopathogenic fungus Metarhizium brunneum, and a H. bacteriophora+M. brunneum combination treatment to C. nasturtii larvae, pupae, and cocoons was investigated. In the laboratory, all three nematode species successfully reproduced inside C. nasturtii larvae: H. bacteriophora produced the highest number of infective juveniles per larva, followed by S. carpocapsae and S. feltiae. H. bacteriophora and the H. bacteriophora+M. brunneum combination treatment generally caused the highest mortality levels to all C. nasturtii life stages at 20°C and 25°C, whereas S. feltiae caused the highest mortality to larvae and pupae at 16°C. No nematode species caused significant mortality when applied in foliar treatments to the infested host plant meristem and, in spite of high mortality, an antagonistic interaction was observed in the H. bacteriophora+M. brunneum combination treatment when compared with expected mortality. In trials conducted in broccoli fields in Elora, Ontario, M. brunneum suppressed adult emergence of C. nasturtii from infested soil in 2012 and all nematode treatments successfully suppressed adult emergence in 2013; however, no significant effects were observed in field trials conducted in Baden, Ontario.

The role of a student-run clinic in providing primary care for Calgary's homeless populations: a qualitative study.

BACKGROUND: Despite the increasing popularity of Student-Run Clinics (SRCs) in Canada, there is little existing literature exploring their role within the Canadian healthcare system. Generalizing American literature to Canadian SRCs is inappropriate, given significant differences in healthcare delivery between the two countries. Medical students at the University of Calgary started a SRC serving Calgary's homeless population at the Calgary Drop-In and Rehabilitation Centre (CDIRC). This study explored stakeholders' desired role for a SRC within Calgary's primary healthcare system and potential barriers it may face. METHODS: Individual and group semi-structured interviews were undertaken with key stakeholders in the SRC project: clients (potential patients), CDIRC staff, staff from other stakeholder organizations, medical students, and faculty members. Convenience sampling was used in the recruitment of client participants. Interview transcripts were analyzed using a coding template which was derived from the literature. RESULTS: Participants identified factors related to the clinic and to medical students that suggest there is an important role for a SRC in Calgary. The clinic was cited as improving access to primary healthcare for individuals experiencing homelessness. It was suggested that students may be ideally suited to provide empathetic healthcare to this population. Barriers to success were identified, including continuity of care and the exclusion of some subsets of the homeless population due to location. CONCLUSIONS: SRCs possess several unique features that may make them a potentially important primary healthcare resource for the homeless. Participants identified numerous benefits of the SRC to providing primary care for homeless individuals, as well as several important limitations that need to be accounted for when designing and implementing such a program.

Iatrogenic Budd-Chiari Syndrome Secondary to Transhepatic Hemodialysis Catheterization.

Hepatic vein thrombosis (HVT), or Budd-Chiari syndrome, is a rare disorder resulting from the obstruction of blood flow from the liver to the inferior vena cava and eventually back to the heart. HVT can lead to extensive hepatocellular injury and portal hypertension and may require liver transplantation in patients. We present a rare cause of HVT and subsequent liver failure secondary to transhepatic venous catheterization for hemodialysis (HD) in a patient with end-stage renal disease (ESRD).

Factors Associated With Initiation of Antidepressant Medication in Adults With Type 1 and Type 2 Diabetes: A Primary Care Retrospective Cohort Study in Ontario, Canada.

OBJECTIVES: Depression in patients with diabetes mellitus is common and associated with poorer outcomes. This study aims to identify demographic, socioeconomic and medical factors associated with the initiation of antidepressant medication after a diagnosis of diabetes in adult patients without a previous prescription for antidepressants. We also examined frequency of primary care visits in the year after antidepressant initiation compared with the year before treatment began. METHODS: This was a retrospective cohort study using routinely collected electronic medical record data spanning January 2011 to December 2019 from the University of Toronto Practice-based Research Network (UTOPIAN) Data Safe Haven. Our primary outcome was a first prescription for an antidepressant in patients with diabetes. We used a mixed-effects logistic regression model to identify sociodemographic and medical factors associated with this event. RESULTS: Among 22,750 patients with diabetes mellitus, 3,055 patients (13.4%) began taking an antidepressant medication. Increased odds of antidepressant initiation were observed in younger patients (odds ratio [OR], 1.77; 95% confidence interval [CI], 1.39 to 2.26), females (OR, 1.60; 95% CI, 1.46 to 1.7), those receiving insulin treatment (OR, 1.59; 95% CI, 1.43 to 1.78) and cases of polypharmacy (OR, 3.67; 95% CI, 3.29 to 4.11). There was an increase in the mean number of primary care visits from 4.6 to 5.9 per year after antidepressant initiation. CONCLUSIONS: In patients with diabetes, age, sex and medical characteristics were associated with the initiation of antidepressants. These patients accessed primary care more frequently. Screening and prevention of depression, particularly in these subgroups, could reduce its personal and systemic burdens.

N-alkyldinaphthocarbazoles, azaheptacenes, for solution-processed organic field-effect transistors.

Substituted N-alkyldinaphthocarbazoles were synthesized using a key double Diels-Alder reaction. The angular nature of the dinaphthocarbazole system allows for increased stability of the conjugated system relative to linear analogues. The N-alkyldinaphthocarbazoles were characterized by UV-vis absorption and fluorescence spectroscopy as well as cyclic voltammetry. X-ray structure analysis based on synchrotron X-ray powder diffraction revealed that the N-dodecyl-substituted compound was oriented in an intimate herringbone packing motif, which allowed for p-type mobilities of 0.055 cm(2) V(-1) s(-1) from solution-processed organic field-effect transistors.

Case report: Morphological changes evident after manual therapy in two cases of late-diagnosed developmental dysplasia of the hip.

Background: Late diagnosed Developmental Dysplasia of the Hip (DDH) is the detection of DDH after 3 months of age and is associated with significantly poorer outcomes than when diagnosed and managed early. Late diagnosed DDH has lower rates of success with bracing, higher rates of surgery and higher rates of complications, including avascular necrosis of the femoral head and early osteoarthritis of the hip. We describe two cases of late-diagnosed DDH which demonstrated changes in femoroacetabular joint morphology on radiographic interpretation after a 6-month trial period of manual therapy. Case Presentation: Two cases (13 and 30 months of age) with late-diagnosed DDH presented to a private chiropractic clinic for conservative, non-bracing management. One case had unilateral DDH and the other bilateral DDH. A trial of manual therapy was utilized over a 6-month period. Both cases demonstrated changes to femoroacetabular morphology as well as improvements in gross motor activity and lower extremity muscle tone. Conclusion: Manual therapy, as an adjunct or alternative to static bracing, may be of benefit in individuals with late-diagnosed DDH not responding to bracing, and prior to more invasive interventions. Additional cases of manual therapy-based management of this condition are required to inform the design of future trials to investigate this hypothesis.

Interventions to Improve Metabolic Risk Screening Among Children and Adolescents on Antipsychotic Medication: A Systematic Review.

Objective: Antipsychotic use among youth is common and is associated with metabolic side effects such as weight gain. Guidelines recommend periodic screening of metabolic measures in youth prescribed antipsychotics; however, a guideline-to-practice gap exists. We systematically reviewed the literature to synthesize the knowledge from interventions that aim to improve antipsychotic metabolic screening. We described the interventions' effect on screening rates, the strategies used for improvement, and study quality. Methods: We conducted a systematic review of studies that attempted to improve antipsychotic metabolic risk screening practices among pediatric populations published between 2004 and August 2019. We included studies with an improvement intervention that compared screening rates before and after the intervention. We extracted data about study characteristics, screening rates in pre- and postintervention groups, strategies used to influence screening practices, and assessed studies' risk of bias. This review was prospectively registered with PROSPERO #CRD42018088241. Results: We identified six studies that demonstrated modest improvements in median metabolic screening rates for waist circumference (0%-16%), glucose (9%-39%), and lipids (11%-37%). Median postintervention screening rates were higher for weight and blood pressure (84% and 72.5%) compared with glucose and lipids (39% and 37%). Interventions used a variety of improvement strategies to address patient-, provider-, and organization-level barriers for screening, including increasing patient and provider knowledge regarding antipsychotic side effects, fostering social clinical environments that promote screening, and organizational commitment for screening antipsychotic-treated youth. All interventions were deemed at high risk of bias due to uncontrolled design and lack of adjustment for confounders. Conclusions: Included studies reported partial success in improving antipsychotic screening rates but were of poor methodological quality. Common improvement strategies may affect provider behavior to conduct metabolic screening, but these need to be tailored to local resources and organization structure. Future studies need to use rigorous methodology and theory-informed improvement strategies aligned with organizational actions to prioritize safe and judicious practice of antipsychotics among pediatric populations.

An Update on Peroneal Nerve Entrapment and Neuropathy.

Peroneal neuropathy is the most common compressive neuropathy of the lower extremity. It should be included in the differential diagnosis for patients presenting with foot drop, the pain of the lower extremity, or numbness of the lower extremity. Symptoms of peroneal neuropathy may occur due to compression of the common peroneal nerve (CPN), superficial peroneal nerve (SPN), or deep peroneal nerve (DPN), each with different clinical presentations. The CPN is most commonly compressed by the bony prominence of the fibula, the SPN most commonly entrapped as it exits the lateral compartment of the leg, and the DPN as it crosses underneath the extensor retinaculum. Accurate and timely diagnosis of any peroneal neuropathy is important to avoid progression of nerve injury and permanent nerve damage. The diagnosis is often made with physical exam findings of decreased strength, altered sensation, and gait abnormalities. Motor nerve conduction studies, electromyography studies, and diagnostic nerve blocks can also assist in diagnosis and prognosis. First-line treatments include removing anything that may be causing external compression, providing stability to unstable joints, and reducing inflammation. Although many peroneal nerve entrapments will resolve with observation and activity modification, surgical treatment is often required when entrapment is refractory to these conservative management strategies. Recently, additional options including microsurgical decompression and percutaneous peripheral nerve stimulation have been reported; however, large studies reporting outcomes are lacking.

Routine screening for developmental dysplasia of the hip by chiropractors: a case report of late diagnosis in an infant.

BACKGROUND: Developmental Dysplasia of the Hip (DDH) is a common musculoskeletal condition of infancy, but diagnosis can be delayed. In parts of Australia, after the four-month routine assessment, there is a 16-week interval before the next well-child assessment. This may result in a delay in diagnosing late developing DDH. CASE PRESENTATION: This case report describes the diagnosis and management of an 18-week old infant with late-onset DDH who was successfully managed with simultaneous Pavlik harnessing with Denis Browne Bar. SUMMARY: This case underscores the importance of routine ongoing hip joint screening, inter-professional collaboration of all health care practitioners, and the importance of appropriate training of all practitioners seeing infants, to reduce instances of undetected DDH, reduce medical burden, and prevent otherwise unnecessary surgical intervention.

CONTEXTE: La dysplasie développementale de la hanche (DDH) est une affection musculosquelettique courante chez les enfants en bas âge. Il arrive que le diagnostic de cette maladie soit tardif. Dans certaines régions de l'Australie, après l'examen de routine à l'âge demquatre mois, 16 semaines s'écoulent avant le prochain examen de l'enfant bien portant. Par conséquent, le diagnostic d'une DDH à évolution tardive risque d'être retardé. EXPOSÉ DU CAS: Ce compte rendu présente le cas d'un nourrisson de 18 semaines présentant d'une DDH à évolution tardive, qui a été traitée avec succès par le port du harnais de Pavlik et de l'attelle de Denis-Browne. RÉSUMÉ: Ce cas souligne l'importance d'un dépistage systématique et continu de la dysplasie de la hanche, de la collaboration entre tous les praticiens de santé et d'une formation appropriée pour tous les praticiens traitant des nourrissons et ce, pour réduire le nombre de cas de DDH non détectés, réduire le fardeau pour les services médicaux et prévenir une intervention chirurgicale autrement inutile.

Efficacy of Biopesticides for Management of the Swede Midge (Diptera: Cecidomyiidae).

Management of the swede midge, Contarinia nasturtii Kieffer, in North American crucifer production relies on crop rotation and the timely application of synthetic insecticides, based on pheromone trap monitoring of local adult populations. Organically acceptable formulations of azadirachtin, pyrethrin, and spinosad, and a commercial biopesticide containing the entomopathogenic fungus, Beauveria bassiana, were evaluated for their effects on larval mortality and oviposition deterrence in the greenhouse, and on damage symptoms in the field. In greenhouse trials, pyrethrin and spinosad treatments applied up to 24 h prior to C. nasturtii exposure resulted in significant reductions in oviposition on host plants, whereas azadirachtin and B. bassiana only deterred oviposition when applied 2 h prior to exposure. Spinosad caused the highest larval reduction (∼96%) on cauliflower meristems, while azadirachtin, B. bassiana, and pyrethrin caused significant larval reduction when applied preoviposition and significant mortality when applied postoviposition. Field trials conducted with these insecticides on broccoli in 2011 produced no significant reductions in overall damage levels; however, B. bassiana treatments produced more marketable plants than did the control. In 2013, all treatments significantly reduced overall damage levels and all treatments, except B. bassiana, produced more uninfested and marketable plants than the control. Field applications of these alternative insecticides may be effective in protecting yields of broccoli and cauliflower, when combined with other tactics in an integrated pest management program.

Assessment of coronary arterial restenosis with phase-contrast magnetic resonance imaging measurements of coronary flow reserve.

BACKGROUND: After successful percutaneous coronary arterial revascularization, 25% to 60% of subjects have restenosis, a recurrent coronary arterial narrowing at the site of the intervention. At present, restenosis is usually detected invasively with contrast coronary angiography. This study was performed to determine if phase-contrast MRI (PC-MRI) could be used to detect restenosis noninvasively in patients with recurrent chest pain after percutaneous revascularization. METHODS AND RESULTS: Seventeen patients (15 men, 2 women, age 36 to 77 years) with recurrent chest pain >3 months after successful percutaneous intervention underwent PC-MRI measurements of coronary artery flow reserve followed by assessments of stenosis severity with computer-assisted quantitative coronary angiography. The intervention was performed in the left anterior descending coronary artery in 15 patients, one of its diagonal branches in 2 patients, and the right coronary artery in 1 patient. A PC-MRI coronary flow reserve value /=70% and >/=50%, respectively. CONCLUSIONS: Assessments of coronary flow reserve with PC-MRI can be used to identify flow-limiting stenoses (luminal diameter narrowings >70%) in patients with recurrent chest pain in the months after a successful percutaneous intervention.

Abciximab readministration: results of the ReoPro Readministration Registry.

BACKGROUND: Platelet glycoprotein IIb/IIIa blockade with abciximab (ReoPro) improves the clinical outcomes of percutaneous coronary intervention. This registry was conducted to characterize the effects of repeated administration of abciximab during intervention. METHODS AND RESULTS: We recruited 500 consecutive patients at 22 centers in the United States who were receiving abciximab for at least a second time during percutaneous coronary intervention. Safety was measured as the incidence of hypersensitivity reactions, major bleeding, and thrombocytopenia. Efficacy was assessed as event-free clinical success. Human antichimeric antibody (HACA) responses were also characterized. There were no cases of hypersensitivity (95% upper confidence bound, 0.3%), major bleeding, or death. Clinical success was 94.4%. Thrombocytopenia occurred in 23 patients (4.6%; 95% CI, 2.8% to 6.4%), including 12 (2.4%; 95% CI, 1.1% to 3.7%) who developed profound thrombocytopenia (<20x10(9) cells/L). In 2 patients (0.4%), profound thrombocytopenia did not develop until after hospital discharge; in 4 (0.8%), profound thrombocytopenia recurred despite platelet transfusion. Before a first readministration, a positive HACA titer was present in 22 of 454 patients (4.8%); after a first readministration, an additional 82 of 432 (19.0%) became HACA-positive. HACA did not neutralize the in vitro inhibition of platelet aggregation by abciximab or correlate with clinical events. CONCLUSIONS: The results, including overall rates of thrombocytopenia, were consistent with randomized clinical trials of first abciximab treatment. However, there was a shift from mild to profound thrombocytopenia, and cases of delayed presentation and of recurrent thrombocytopenia were seen. These findings suggest that indications and guidelines for first-time use apply to retreatment, particularly the systematic monitoring for thrombocytopenia.

Point-of-care measured platelet inhibition correlates with a reduced risk of an adverse cardiac event after percutaneous coronary intervention: results of the GOLD (AU-Assessing Ultegra) multicenter study.

BACKGROUND: The optimal level of platelet inhibition with a glycoprotein (GP) IIb/IIIa antagonist necessary to minimize thrombotic complications in patients undergoing a percutaneous coronary intervention (PCI) is currently unknown. METHODS AND RESULTS: Five hundred patients undergoing a PCI with the planned use of a GP IIb/IIIa inhibitor had platelet inhibition measured at 10 minutes, 1 hour, 8 hours, and 24 hours after the initiation of therapy with the Ultegra Rapid Platelet Function Assay (Accumetrics). Major adverse cardiac events (MACES: composite of death, myocardial infarction, and urgent target vessel revascularization) were prospectively monitored, and the incidence correlated with the measured level of platelet function inhibition at all time points. One quarter of all patients did not achieve >/=95% inhibition 10 minutes after the bolus and experienced a significantly higher incidence of MACEs (14.4% versus 6.4%, P=0.006). Patients whose platelet function was <70% inhibited at 8 hours after the start of therapy had a MACE rate of 25% versus 8.1% for those >/=70% inhibited (P=0.009). By multivariate analysis, platelet function inhibition >/=95% at 10 minutes after the start of therapy was associated with a significant decrease in the incidence of a MACE (odds ratio 0.46, 95% CI 0.22 to 0.96, P=0.04). CONCLUSIONS: Substantial variability in the level of platelet function inhibition is achieved with GP IIb/IIIa antagonist therapy among patients undergoing PCI. The level of platelet function inhibition as measured by a point-of-care assay is an independent predictor for the risk of MACEs after PCI.

Transluminal extraction catheter atherectomy followed by immediate stenting in treatment of saphenous vein grafts.

OBJECTIVES: The purpose of this study was to evaluate the effectiveness of transluminal extraction catheter (TEC) atherectomy followed by immediate Palmaz-Schatz coronary stenting of coronary bypass vein grafts. BACKGROUND: Degeneration of saphenous vein coronary bypass grafts has become a common problem. Repeat bypass surgery is associated with greater risk and a poorer outcome than the initial operation. Moreover, percutaneous interventional procedures in vein grafts have been associated with high procedural complication rates, including distal embolization, and high restenosis rates. TEC atherectomy may reduce distal embolization, and stenting may reduce restenosis rates. METHODS: We evaluated the procedural, hospital and clinical outcomes of TEC atherectomy followed by immediate Palmaz-Schatz coronary stenting of 53 vein grafts in 49 consecutive patients. The strategy was to limit instrumentation to extraction debulking and to stabilizing the site with stent deployment before using balloon dilation for optimal gain in lumen diameter. RESULTS: Results are shown as mean value (95% confidence interval [CI]). The mean graft age was 9.2 years (95% CI 7.9 to 10.5), and 1.0 (95% CI 1 to 1) TEC cutter (2.2 mm [95% CI 2.1 to 2.3]) and 1.7 (95% CI 1.4 to 2.0) Palmaz-Schatz coronary stents/ vein graft were used. The procedural success rate was 98%, with a minimal lumen diameter at baseline of 1.3 mm (95% CI 1.1 to 1.5), increasing to 3.9 mm (95% CI 3.6 to 4.2) (p < 0.05) after the TEC-stent procedure. Procedural complications occurred infrequently: graft perforation in 1 (2%) of 53 patients and distal embolization in 1 (2%) of 53 (same patient). In-hospital complications included non-Q wave myocardial infarction in two patients and death after a successful procedure in three (6%) (n = 1 each: massive bleeding from the catheter site; sepsis; and acute myocardial infarction with asystole in the distribution of the stented vessel). The event-free survival rate to hospital discharge was 90%. Clinical follow-up (13 months [95% CI 11 to 15]) was available for all patients. There were five (11%) revascularization procedures (three bypass grafts and two percutaneous transluminal coronary interventions), four (9%) nonfatal myocardial infarctions and five (11%) deaths, for a cumulative rate of 28% for any adverse outcome occurring in 13 of 46 patients. CONCLUSIONS: TEC atherectomy followed by immediate Palmaz-Schatz coronary stenting of stenoses in old (> 9 years) saphenous vein grafts can be successfully performed, with a low incidence of procedural and hospital complications. Clinical restenosis rates are low and less than those previously reported; however, late morbid cardiac events are still frequent in this high risk group of patients. These observational findings suggest that this technique may improve percutaneous management of vein graft disease, but optimal long-term management strategies remain to be determined.

Qualitative and quantitative contrasts in the mechanisms of lumen enlargement by coronary balloon angioplasty and directional coronary atherectomy.

OBJECTIVES: This study was designed to define and contrast the mechanisms of lumen enlargement from coronary balloon angioplasty and directional coronary atherectomy using intracoronary ultrasound imaging in vivo. BACKGROUND: The mechanisms of lumen enlargement produced by percutaneous transluminal coronary balloon angioplasty and directional coronary atherectomy are not known because the coronary artery wall has not previously been studied both before and after dilation. METHODS: We used intracoronary ultrasound to quantitate coronary lumen, vessel and plaque area both before and immediately after successful coronary angioplasty (n = 30) and directional coronary atherectomy (n = 25) at the site of most severe stenosis. RESULTS: Angioplasty increased lumen area by 2.80 +/- 0.25 mm2 (mean +/- SE, p < 0.0001). Eighty-one percent of this lumen gain resulted from an increase in vessel area and the remaining 19% from a reduction in plaque area. Lumen gain of individual lesions was separated into three groups: 67% had an increase in vessel area (vessel expansion), 13% had a decrease in plaque area and 20% had a combination of both. In contrast, vessel expansion contributed only 22% of the lumen gain with directional coronary atherectomy, with the majority (78%) of increase in lumen size coming from a reduction in plaque area. Directional coronary atherectomy increased lumen area from 2.36 +/- 0.05 to 7.00 +/- 0.28 mm2 (p < 0.0001). Plaque reduction was the sole mechanism in 60% of lesions, vessel expansion was the sole mechanism in 12% and a combination of both mechanisms occurred in 28%. Lumen enlargement of eccentric lesions treated with directional coronary atherectomy was more commonly associated with plaque reduction (p < 0.02), whereas eccentricity did not affect the mechanism of lumen enlargement with coronary angioplasty. CONCLUSIONS: This is the first study to systematically examine the coronary artery wall in vivo at the site of a severe stenosis both before and after catheter-based interventions in humans. Lumen enlargement from coronary angioplasty occurs predominantly from vessel expansion or stretching, although a reduction in plaque area contributes to the lumen gain in many patients and is the sole mechanism in a few. Lumen gain from directional coronary atherectomy is predominantly from reduction in plaque area (probably owing to tissue removal), although vessel stretching (balloon effect) occurs and is the sole mechanism in a small minority of vessels. Plaque reduction is more common in directional coronary atherectomy of eccentric lesions.