Evaluation of the TraumaGuard Balloon-in-Balloon Catheter Design for Intra-Abdominal Pressure Monitoring: Insights from Pig and Human Cadaver Studies.

Introduction: Intra-abdominal pressure (IAP) monitoring is crucial for the detection and prevention of intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS). In the 1970s, air-filled catheters (AFCs) for urodynamic studies were introduced as a solution to overcome the limitations of water-perfused catheters. Recent studies have shown that for correct IAP measurement with traditional AFC, the bladder needs to be primed with 25 mL of saline solution to allow pressure wave transmission to the transducer outside of the body, which limits continuous IAP monitoring. Methods: In this study, a novel triple balloon, air-filled TraumaGuard (TG) catheter system from Sentinel Medical Technologies (Jacksonville, FL, USA) with a unique balloon-in-balloon design was evaluated in a porcine and cadaver model of IAH via laparoscopy (IAPgold). Results: In total, 27 and 86 paired IAP measurements were performed in two pigs and one human cadaver, respectively. The mean IAPTG was 20.7 ± 10.7 mmHg compared to IAPgold of 20.3 ± 10.3 mmHg in the porcine study. In the cadaver investigation, the mean IAPTG was 15.6 ± 10.8 mmHg compared to IAPgold of 14.4 ± 10.4 mmHg. The correlation, concordance, bias, precision, limits of agreement, and percentage error were all in accordance with the WSACS (Abdominal Compartment Society) recommendations and guidelines for research. Conclusions: These findings support the use of the TG catheter for continuous IAP monitoring, providing early detection of elevated IAP, thus enabling the potential for prevention of IAH and ACS. Confirmation studies with the TraumaGuard system in critically ill patients are warranted to further validate these findings.

Clinical, Imaging, and Pathologic Features of Conditions with Combined Esophageal and Cutaneous Manifestations.

A variety of clinically significant conditions can affect both the esophagus and the skin. Esophageal and cutaneous manifestations may directly reflect the underlying disease process, as in infections such as herpes simplex virus, bullous diseases such as epidermolysis bullosa and mucous membrane pemphigoid, connective tissue diseases such as systemic sclerosis, and inflammatory diseases such as lichen planus. Alternatively, esophageal and cutaneous findings may result from conditions that are closely associated with and potentially pathognomonic for but distinct from the underlying disease process, as in genetic diseases such as Cowden syndrome or paraneoplastic syndromes such as acrokeratosis paraneoplastica. Other diseases such as Crohn disease may have cutaneous manifestations that directly reflect the same underlying inflammatory process that affects the gastrointestinal tract or cutaneous manifestations that represent reactive or associated conditions distinct from the underlying inflammatory process. The cutaneous manifestations of disease may precede, coincide with, or follow the esophageal manifestations of disease. The authors present the characteristic clinical features and imaging findings associated with common and uncommon conditions that have esophageal and cutaneous manifestations. Each condition is presented with a brief overview, discussion of salient clinical and cutaneous manifestations, and description of the typical esophageal imaging findings, with particular attention to implications for diagnosis, prognosis, and treatment. Recognition of potential associations between cutaneous lesions and esophageal imaging findings is important for establishing a specific diagnosis or generating a meaningful differential diagnosis.

Esophageal Lichen Planus: Clinical and Radiographic Findings in Eight Patients.

OBJECTIVE: The purpose of this study is to present the clinical and radiographic findings of esophageal lichen planus. MATERIALS AND METHODS: A search of computerized medical records identified 15 patients with pathologic findings of esophageal lichen planus on endoscopic biopsy specimens. Three other patients had presumed esophageal lichen planus, although no biopsy specimens were obtained. Twelve of these 18 patients (67%) had double-contrast esophagography performed at our institution; for eight of the 12 patients (67%), the studies revealed abnormalities in the esophagus. These eight patients constituted our study group. The barium esophagrams and medical records of these eight patients were reviewed to determine the clinical, radiographic, and endoscopic findings of esophageal lichen planus as well as the treatment and patient outcome. RESULTS: All eight patients were women (median age, 66.5 years), and all eight presented with dysphagia (mean duration, 3.2 years). Four patients had previous lichen planus that involved the skin (n = 1), the oral cavity (n = 2), or both (n = 1), and one patient later had lichen planus that involved the vagina. Five patients had a small-caliber esophagus with diffuse esophageal narrowing. The remaining three patients had segmental strictures in the cervical (n = 1), upper thoracic (n = 1), and distal thoracic (n = 1) esophagus. CONCLUSION: Esophageal lichen planus typically occurs in older women with longstanding dysphagia and often develops in the absence of extraesophageal disease. Barium esophagrams may reveal a small-caliber esophagus or, less commonly, segmental esophageal strictures. Greater awareness of the radiographic findings of esophageal lichen planus hopefully will lead to earlier diagnosis and better management of this condition.

History and Evolution of the Barium Swallow for Evaluation of the Pharynx and Esophagus.

This article reviews the history of the barium swallow from its early role in radiology to its current status as an important diagnostic test in modern radiology practice. Though a variety of diagnostic procedures can be performed to evaluate patients with dysphagia or other pharyngeal or esophageal symptoms, the barium study has evolved into a readily available, non-invasive, and cost-effective technique that can facilitate the selection of additional diagnostic tests and guide decisions about medical, endoscopic, or surgical management. This article focuses on the evolution of fluoroscopic equipment, radiography, and contrast media for evaluating the pharynx and esophagus, the importance of understanding pharyngoesophageal relationships, and major advances that have occurred in the radiologic diagnosis of select esophageal diseases, including gastroesophageal reflux disease, infectious esophagitis, eosinophilic esophagitis, esophageal carcinoma, and esophageal motility disorders.

Findings of Esophagography for 25 Patients After Peroral Endoscopic Myotomy for Achalasia.

OBJECTIVE: The purpose of this study is to better characterize the findings of esophagography after peroral endoscopic myotomy for achalasia. MATERIALS AND METHODS: We evaluated 25 patients who underwent peroral endoscopic myotomy for achalasia. The findings noted on pre- and postprocedural esophagrams were reviewed retrospectively and were correlated with clinical outcomes. RESULTS: None of the patients had esophageal perforation noted on esophagrams obtained after myotomy, and all but two patients had a hospital stay that lasted 1 day only. Esophagrams obtained on postoperative day 1 revealed endoscopic clips in 25 patients (100%), pneumoperitoneum in 18 (72%), retroperitoneal gas in 10 (40%), gastric pneumatosis in nine (36%), intramural dissections in seven (28%), and pneumomediastinum in four (16%). Repeat esophagrams obtained 3 weeks later for 22 of the patients revealed endoscopic clips in 16 patients (73%) and intramural dissections in five patients (23%), but the remaining findings had resolved. Eighteen patients (72%) had a successful myotomy and seven (28%) had suboptimal results on the basis of clinical outcomes. Observation of a distal esophageal width of 5 mm or less on postprocedural esophagrams was often associated with suboptimal results. CONCLUSION: Peroral endoscopic myotomy is a novel procedure that is less invasive than is laparoscopic Heller myotomy for the treatment of achalasia, with fewer complications and shorter recovery times. Radiologists should be aware of the findings expected on esophagography (including pneumoperitoneum, retroperitoneal gas, gastric pneumatosis, intramural dissections, and pneumomediastinum) and should also know that fluoroscopic studies may be helpful for predicting patient outcomes on the basis of the width of the distal esophagus after myotomy.

Consensus Statement of Society of Abdominal Radiology Disease-Focused Panel on Barium Esophagography in Gastroesophageal Reflux Disease.

OBJECTIVE: The Society of Abdominal Radiology established a panel to prepare a consensus statement on the role of barium esophagography in gastroesophageal reflux disease (GERD), as well as recommended techniques for performing the fluoroscopic examination and the gamut of findings associated with this condition. CONCLUSION: Because it is an inexpensive, noninvasive, and widely available study that requires no sedation, barium esophagography may be performed as the initial test for GERD or in conjunction with other tests such as endoscopy.

History, evolution, and current status of radiologic imaging tests for colorectal cancer screening.

Colorectal cancer screening is thought to be an effective tool with which to reduce the mortality from colorectal cancer through early detection and removal of colonic adenomas and early colon cancers. In this article, we review the history, evolution, and current status of imaging tests of the colon-including single-contrast barium enema, double-contrast barium enema, computed tomographic (CT) colonography, and magnetic resonance (MR) colonography-for colorectal cancer screening. Despite its documented value in the detection of colonic polyps, the double-contrast barium enema has largely disappeared as a screening test because it is widely perceived as a labor-intensive, time-consuming, and technically demanding procedure. In the past decade, the barium enema has been supplanted by CT colonography as the major imaging test in colorectal cancer screening in the United States, with MR colonography emerging as another viable option in Europe. Although MR colonography does not require ionizing radiation, the radiation dose for CT colonography has decreased substantially, and regular screening with this technique has a high benefit-to-risk ratio. In recent years, CT colonography has been validated as an effective tool for use in colorectal cancer screening that is increasingly being disseminated.

Imaging of bariatric surgery: normal anatomy and postoperative complications.

Obesity is a disease that has reached epidemic proportions in the United States and around the world. During the past 2 decades, bariatric surgery has become an increasingly popular form of treatment for morbid obesity. The most common bariatric procedures performed include laparoscopic Roux-en-Y gastric bypass, laparoscopic adjustable gastric banding, and laparoscopic sleeve gastrectomy. Fluoroscopic upper gastrointestinal examinations and abdominal computed tomography (CT) are the major imaging tests used to evaluate patients after these various forms of bariatric surgery. The purpose of this article is to present the surgical anatomy and normal imaging findings and postoperative complications for these bariatric procedures at fluoroscopic examinations and CT. Complications after Roux-en-Y gastric bypass include anastomotic leaks and strictures, marginal ulcers, jejunal ischemia, small bowel obstruction, internal hernias, intussusception, and recurrent weight gain. Complications after laparoscopic adjustable gastric banding include stomal stenosis, malpositioned bands, pouch dilation, band slippage, perforation, gastric volvulus, intraluminal band erosion, and port- and band-related problems. Finally, complications after sleeve gastrectomy include postoperative leaks and strictures, gastric dilation, and gastroesophageal reflux. The imaging features of these various complications of bariatric surgery are discussed and illustrated.

Imaging and clinicopathologic features of esophageal gastrointestinal stromal tumors.

OBJECTIVE: The purpose of this article is to describe the imaging and clinicopathologic characteristics of esophageal gastrointestinal stromal tumors (GISTs) and to emphasize the features that differentiate esophageal GISTs from esophageal leiomyomas. MATERIALS AND METHODS: A pathology database search identified all surgically resected or biopsied esophageal GISTs, esophageal leiomyomas, and esophageal leiomyosarcomas from 1994 to 2012. Esophageal GISTs were included only if imaging studies (including CT, fluoroscopic, or (18)F-FDG PET/CT scans) and clinical data were available. RESULTS: Nineteen esophageal mesenchymal tumors were identified, including eight esophageal GISTs (42%), 10 esophageal leiomyomas (53%), and one esophageal leiomyosarcoma (5%). Four patients (50%) with esophageal GIST had symptoms, including dysphagia in three (38%), cough in one (13%), and chest pain in one (13%). One esophageal GIST appeared on barium study as a smooth submucosal mass. All esophageal GISTs appeared on CT as well-marginated predominantly distal lesions, isoattenuating to muscle, that moderately enhanced after IV contrast agent administration. Compared with esophageal leiomyomas, esophageal GISTs tended to be more distal, larger, and more heterogeneous and showed greater IV enhancement on CT. All esophageal GISTs showed marked avidity (mean maximum standardized uptake value, 16) on PET scans. All esophageal GISTs were positive for c-KIT (a cell-surface transmembrane tyrosine kinase also known as CD117) and CD34. On histopathology, six esophageal GISTs (75%) were of the spindle pattern and two (25%) were of a mixed spindle and epithelioid pattern. Five esophageal GISTs had exon 11 mutations (with imatinib sensitivity). Clinical outcome correlated with treatment strategy (resection plus adjuvant therapy or resection alone) rather than risk stratification. CONCLUSION: Esophageal GISTs are unusual but clinically important mesenchymal neoplasms. Although esophageal GISTs and esophageal leiomyomas had overlapping imaging features, esophageal GISTs tended to be more distal, larger, more heterogeneous, and more enhancing on CT and were markedly FDG avid on PET. Given their malignant potential, esophageal GISTs should be included in the differential diagnosis of intramural esophageal neoplasms.

From the radiologic pathology archives: gastrointestinal lymphoma: radiologic and pathologic findings.

Gastrointestinal (GI) lymphoma encompasses a heterogeneous group of neoplasms that have a common lymphoid origin but variable pathologic and imaging features. Extranodal marginal zone B-cell lymphoma (ENMZL) and diffuse large B-cell lymphoma (DLBCL) are the most common. ENMZL usually occurs in the stomach, where it is associated with chronic infection by Helicobacter pylori, and is typically a superficial spreading lesion that causes mucosal nodularity or ulceration and mild wall thickening. DLBCL may arise de novo or from transformation of ENMZL or other low-grade lymphomas. This form of lymphoma produces extensive wall thickening or a bulky mass, but obstruction is uncommon. Mantle cell lymphoma is the classic cause of lymphomatous polyposis, but multiple polyps or nodules can also be seen with ENMZL and follicular lymphoma. Burkitt lymphoma is usually characterized by an ileocecal mass or wall thickening in the terminal ileum in young children, often in the setting of widespread disease. Primary GI Hodgkin lymphoma, which is rare, may be manifested by a variety of findings, though stenosis is more common than with non-Hodgkin lymphoma. Enteropathy-associated T-cell lymphoma is frequently associated with celiac disease and is characterized by wall thickening, ulceration, and even perforation of the jejunum. Accurate radiologic diagnosis of GI lymphoma requires a multifactorial approach based on the clinical findings, site of involvement, imaging findings, and associated complications.

More than just metastases: a practical approach to solid mesenteric masses.

The abdominal mesenteries are important peritoneal structures that give rise to a wide spectrum of abnormalities, including solid mesenteric masses. Despite similarities in appearance, solid masses in the mesentery may have diverse etiologies, ranging from benign to highly malignant. While metastases are the most common cause of solid masses in the mesentery, other less common conditions are also important diagnostic considerations. This article reviews four pathologic entities (sclerosing mesenteritis, carcinoid tumors, desmoids tumors, and gastrointestinal stromal tumors) that may be manifested on abdominal imaging examinations by one or more mesenteric masses. These four pathologic entities are used to present a systematic approach to the radiographic characterization of solid mesenteric masses based on the morphology of the lesions, locoregional effects, and distant findings on various abdominal imaging examinations.

From the radiologic pathology archives: esophageal neoplasms: radiologic-pathologic correlation.

Esophageal neoplasms have a wide spectrum of clinical features, pathologic findings, and imaging manifestations. Leiomyomas are the most common benign esophageal neoplasm, typically appearing as smoothly marginated intramural masses. Fibrovascular polyps arise in the cervical esophagus, gradually elongating as they are pulled inferiorly by esophageal peristalsis. Granular cell tumors are generally incidental small intramural masses with an appearance similar to that of leiomyomas. Malignant esophageal neoplasms are a common cause of cancer mortality, particularly squamous cell carcinoma (SCC) and adenocarcinoma. Both of these tumors occur in older men, most often appearing as irregular infiltrative lesions at barium examination, with evidence of tumor spread beyond the esophagus at cross-sectional imaging. Adenocarcinoma arises from Barrett esophagus and is much more likely than SCC to involve the gastroesophageal junction. Esophageal involvement by lymphoma is usually secondary to tumor spread from the stomach or mediastinum. Spindle cell carcinoma is a biphasic malignancy with carcinomatous and sarcomatous elements that forms a bulky polypoid intraluminal mass. Neuroendocrine carcinoma is an aggressive neoplasm that may be hypervascular and is usually associated with metastatic disease at presentation. Understanding the imaging appearances and pathologic bases of esophageal neoplasms is essential for their detection, differential diagnosis, staging, and treatment planning.

Bevacizumab-induced perforation of the gastrointestinal tract: clinical and radiographic findings in 11 patients.

AIM: To present the gastrointestinal (GI) complications associated with bevacizumab therapy and their findings on abdominal imaging studies. METHODS: A computerized search identified 11 patients with GI complications of bevacizumab therapy on abdominal CT (n = 11) and fluoroscopic GI contrast studies (n = 4) who met our study criteria (including five patients with ovarian cancer, five with colon cancer, and one with cervical cancer). The medical records and imaging studies were reviewed to determine the clinical and radiographic findings in these patients. RESULTS: All 11 patients had findings of GI perforation on CT, or CT and GI contrast studies. CT revealed a localized extraluminal collection containing gas, fluid, and/or contrast material in eight patients (73%) with focal perforation, and free abdominal air and fluid in three (27%) with free perforation The imaging studies also revealed seven fistulas, including two colovaginal, one rectovaginal, one enterocutaneous, one colocutaneous, one gastrocolic, and one colorectal fistula. Eight (73%) of the 11 patients died within 1 year of the development of GI perforation, and the perforation was felt to be the cause of death in four patients (36%). CONCLUSION: Abdominal CT and fluoroscopic GI contrast studies are useful imaging tests for the diagnosis of potentially life-threatening GI perforation as a complication of bevacizumab therapy. When GI perforation is detected on abdominal imaging studies, treatment with bevacizumab should immediately be discontinued.

Inferior vena cava thrombosis extension into the right atrium: An unusual case report of renal cell carcinoma.

Inferior vena cava filling defects are common findings on computed tomography and magnetic resonance imaging, and accurate determination of pseudo, benign, or malignant thrombus is essential for clinical management. Inferior vena cava thrombosis involvement extending into the right atrium is a rare presentation of renal cell carcinoma. The degree of inferior vena cava and right atrium involvement is critical in determining management and prognosis of patients. Inferior vena cava thrombosis surgical thrombectomy is often a risky procedure due to the intraoperative determination of inferior vena cava thrombosis involvement. Accurate recognition of inferior vena cava thrombosis with right atrial involvement is critical in determining appropriate treatment options and preoperative level of involvement for surgical intervention. This case features a unique presentation of inferior vena cava thrombosis in renal cell carcinoma with right atrial involvement.

Oral metagenomes from Native American Ancestors reveal distinct microbial lineages in the pre-contact era.

OBJECTIVES: Limited studies have focused on how European contact and colonialism impacted Native American oral microbiomes, specifically, the diversity of commensal or opportunistically pathogenic oral microbes, which may be associated with oral diseases. Here, we studied the oral microbiomes of pre-contact Wichita Ancestors, in partnership with the Descendant community, The Wichita and Affiliated Tribes, Oklahoma, USA. MATERIALS AND METHODS: Skeletal remains of 28 Wichita Ancestors from 20 archeological sites (dating approximately to 1250-1450 CE) were paleopathologically assessed for presence of dental calculus and oral disease. DNA was extracted from calculus, and partial uracil deglycosylase-treated double-stranded DNA libraries were shotgun-sequenced using Illumina technology. DNA preservation was assessed, the microbial community was taxonomically profiled, and phylogenomic analyzes were conducted. RESULTS: Paleopathological analysis revealed signs of oral diseases such as caries and periodontitis. Calculus samples from 26 Ancestors yielded oral microbiomes with minimal extraneous contamination. Anaerolineaceae bacterium oral taxon 439 was found to be the most abundant bacterial species. Several Ancestors showed high abundance of bacteria typically associated with periodontitis such as Tannerella forsythia and Treponema denticola. Phylogenomic analyzes of Anaerolineaceae bacterium oral taxon 439 and T. forsythia revealed biogeographic structuring; strains present in the Wichita Ancestors clustered with strains from other pre-contact Native Americans and were distinct from European and/or post-contact American strains. DISCUSSION: We present the largest oral metagenome dataset from a pre-contact Native American population and demonstrate the presence of distinct lineages of oral microbes specific to the pre-contact Americas.

Face Off: 3D-Printed Masks as a Cost-Effective and Reusable Alternative to N95 Respirators: A Feasibility Study.

BACKGROUND: One of the best methods for protection against respiratory diseases is the use of an N95 mask. Supply shortages have demonstrated a significant need for effective alternatives to N95 masks. Benefits of 3D-printed respirators over N95s include reduced cost and ease of production, widespread availability, reusability/sterilizability, and customizability. 3D-printed mask designs have been downloaded thousands of times; however, there is little to no data on the efficacy of these potential alternatives. METHODS: Three of the most popular 3D-printed respirator designs were modified to allow for the Occupational Safety and Health Administration (OSHA) quantitative fit testing that disperses saline into the ambient air and determines concentrations within the mask during multiple trials. Five volunteers conducted standardized fit tests of these masks, as well as an N95 and a KN95, and the results were compared. RESULTS: One of the 3D-printed respirators, low poly COVID-19 face mask respirator (mask 2), achieved a fit factor greater than 100 in every trial, representing sufficient fit according to OSHA protocols. The N95 mask achieved a sufficient fit in 60% of the trials, and none of the remaining masks provided a suitable fit factor reliably according to the OSHA fit test. Further trials showed no change in fit factor when different 3D-printable plastics are used or when a widely available high efficiency particulate air (HEPA) filter was used. CONCLUSION: 3D-printed respirators provide a possible alternative to N95 masks to protect against respiratory pathogens such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Fit testing results demonstrate that certain 3D-printed mask designs may exceed the fit of N95 masks.

The Cost-Effectiveness of Vancomycin Powder in Lumbar Laminectomy.

STUDY DESIGN: Break-even cost analysis. OBJECTIVE: The goal of this study is to examine the cost-effectiveness of vancomycin powder for preventing infection following lumbar laminectomy. METHODS: The product cost of vancomycin powder was obtained from our institution's purchasing records. Infection rates and revision costs for lumbar laminectomy and lumbar laminectomy with fusion were obtained from the literature. A break-even analysis was then performed to determine the absolute risk reduction (ARR) in infection rate to make prophylactic application of vancomycin powder cost-effective. Analysis of lumbar laminectomy with fusion was performed for comparison. RESULTS: Costing $3.06 per gram at our institution, vancomycin powder was determined to be cost-effective in lumbar laminectomy if the infection rate of 4.2% decreased by an ARR of 0.015%. Laminectomy with fusion was also determined to be cost-effective at the same cost of vancomycin powder if the infection rate of 8.5% decreased by an ARR of 0.0034%. The current highest cost reported in the literature, $44.00 per gram of vancomycin powder, remained cost-effective with ARRs of 0.21% and 0.048% for laminectomy and laminectomy with fusion, respectively. Varying the baseline infection rate did not influence the ARR for either procedure when the analysis was performed using the product cost of vancomycin at our institution. CONCLUSIONS: This break-even analysis demonstrates that prophylactic vancomycin powder can be highly cost-effective for lumbar laminectomy. At our institution, vancomycin powder is economically justified if it prevents at least one infection out of 6700 lumbar laminectomy surgeries.

The small-caliber esophagus: radiographic sign of idiopathic eosinophilic esophagitis.

PURPOSE: To evaluate a small-caliber esophagus at barium esophagography with idiopathic eosinophilic esophagitis (IEE) and determine if there is a useful threshold diameter for suggesting this diagnosis. MATERIALS AND METHODS: The institutional review board approved this retrospective study and waived informed consent. This study was HIPAA compliant. A search of the radiology database (by using the search term small-caliber esophagus) revealed 10 patients with a small-caliber esophagus at barium esophagography who had IEE (defined as more than 20 eosinophils per high-power field in endoscopic biopsy specimens). Images were reviewed to characterize findings and determine the length of narrowing. Luminal diameters were measured at three levels for nine patients and nine control subjects, and mean diameter, range, and standard deviation were determined at each level. An analysis of variance test was performed to determine whether the difference between the range of mean thoracic esophageal diameters in patients with IEE versus that in control subjects was significant. RESULTS: All 10 patients had long-segment but variable-length narrowing of the thoracic esophagus (mean length, 15.4 cm) with tapered margins. The mean diameter at the aortic arch, carina, and one vertebral body above the gastroesophageal junction was 13.9, 14.3, and 15.1 mm, respectively, for patients with small-caliber esophagus versus 20.2, 30.3, and 28.7 mm for control subjects. The mean overall diameter was 14.7 mm for patients with small-caliber esophagus versus 26.3 mm for control subjects. In the nine patients in whom the luminal diameter was measured, the mean thoracic esophageal diameter was 20 mm or less; all nine control subjects had a mean thoracic esophageal diameter greater than 20 mm. The difference in the range of mean thoracic esophageal diameters between these two groups was highly significant (P < .0001), so 20 mm was a useful threshold diameter for suggesting this diagnosis. CONCLUSION: The small-caliber esophagus of IEE is characterized at barium esophagography by long-segment but variable-length narrowing of the thoracic esophagus, with a mean length of 15.4 cm, a diameter of 20 mm or less, smooth contours, and tapered margins.

A systematic review of the effect of CYP3A5 genotype on the apparent oral clearance of tacrolimus in renal transplant recipients.

Tacrolimus is a commonly used immunosuppressive agent in renal transplantation. Therapeutic drug monitoring of tacrolimus is recommended because it demonstrates wide pharmacokinetic interpatient variability. Part of that variability may be the result of metabolism by cytochrome P450 3A5 (CYP3A5), which is only expressed in some adult individuals. The expression of CYP3A5 has been linked to the CYP3A5 genotype, in which individuals with one or more wild-type allele (CYP3A5*1) are considered CYP3A5 expressors, and individuals homozygous for the mutant allele CYP3A5*3 are considered nonexpressors. An association has been established between CYP3A5 genotype (expressors versus nonexpressors) and tacrolimus dose requirements to achieve target concentrations. Tacrolimus pharmacokinetic variability is based on bioavailability and systemic clearance, which are represented by apparent oral clearance. The focus of this review was to use a systematic method to investigate whether the CYP3A5 genotype has an effect on the apparent oral clearance of tacrolimus in renal transplant recipients. A total of five studies were identified that reported apparent oral clearance in CYP3A5 expressors and CYP3A5 nonexpressors. The weighted mean apparent oral clearance was found to be 48% lower in CYP3A5 nonexpressors than CYP3A5 expressors (range, 26%-65%). This difference in apparent oral clearance could be used in future studies to guide initial dosing strategies of tacrolimus in renal transplant recipients based on genotype.