Bio

Bio


Afrin Kamal is a board-certified gastroenterologist, who trained at Washington University in internal medicine, Cleveland Clinic in gastroenterology/hepatology, and most recently Stanford University in esophageal and motility diseases. Afrin shares a clinical passion in esophageal motility diseases with an an overlapping interest in health services and outcomes research.

Clinical Focus


  • Gastroenterology
  • Benign esophageal diseases
  • Esophageal motility

Academic Appointments


Boards, Advisory Committees, Professional Organizations


  • Trainee Committee member, American College of Gastroenterology (2018 - Present)

Professional Education


  • Fellowship: Cleveland Clinic Foundation Hospital (2018) OH
  • Fellowship: Stanford University Gastroenterology Fellowship (2019) CA
  • Board Certification: Gastroenterology, American Board of Internal Medicine (2018)
  • Residency: Washington University School Of Medicine Registrar (2014) MO
  • Board Certification, Gastroenterology, American Board of Internal Medicine (2018)
  • Board Certification: Internal Medicine, American Board of Internal Medicine (2014)
  • Medical Education: University of Missouri (2011) MO

Research & Scholarship

Clinical Trials


  • Applying Nutrient Drink Test in Understanding Pathophysiology of CVS Not Recruiting

    Cyclic vomiting syndrome is a disorder characterized by nausea and vomiting, separated by periods without any symptoms. There is very little research on this field at this point and most doctors do not fully understand the disorder. The goal of this study is to assess how the stomach empties food. Participants will be asked to participate in this study because either (a) they have been diagnosed and/or treated for cyclic vomiting syndrome in the past, or (b) they are physically healthy. The study seeks to compare how a healthy person's stomach empties to how the stomach of someone with cyclic vomiting disorder empties.

    Stanford is currently not accepting patients for this trial.

    View full details

Publications

All Publications


  • Mucosal impedance for esophageal disease: evaluating the evidence. Annals of the New York Academy of Sciences Clarke, J. O., Ahuja, N. K., Chan, W. W., Gyawali, C. P., Horsley-Silva, J. L., Kamal, A. N., Vela, M. F., Xiao, Y. 2020

    Abstract

    Impedance has traditionally been employed in esophageal disease as a means to assess bolus flow and reflux episodes. Recent and ongoing research has provided new and novel applications for this technology. Measurement of esophageal mucosal impedance, via either multichannel intraluminal impedance catheters or specially designed endoscopically deployed impedance catheters, provides a marker of mucosal integrity. Mucosal impedance has been shown to segregate gastroesophageal reflux disease (GERD) and eosinophilic esophagitis from non-GERD controls and may play a role in predicting response to reflux intervention. More data are needed with regard to other esophageal subgroups, outcome studies, and functional disease. Our paper reviews the history of impedance in esophageal disease, the means of assessing baseline and mucosal impedance, data with regard to the newly developed mucosal impedance probes, the clinical utility of mucosal impedance in specific clinical conditions, and limitations in our existing knowledge, along with suggestions for future studies.

    View details for DOI 10.1111/nyas.14414

    View details for PubMedID 32588457

  • The role of ambulatory 24-hour esophageal manometry in clinical practice. Neurogastroenterology and motility : the official journal of the European Gastrointestinal Motility Society Kamal, A. N., Clarke, J. O., Oors, J. M., Bredenoord, A. J. 2020: e13861

    Abstract

    High-resolution manometry revolutionized the assessment of esophageal motility disorders and upgraded the classification through the Chicago Classification. A known disadvantage of standard HRM, however, is the inability to record esophageal motility function for an extended time interval; therefore, it represents only a more snapshot view of esophageal motor function. In contrast, ambulatory esophageal manometry measures esophageal motility over a prolonged period and detects motor activity during the entire circadian cycle. Furthermore, ambulatory manometry has the ability to measure temporal correlations between symptoms and motor events. This article aimed to review the clinical implications of ambulatory esophageal manometry for various symptoms, covering literature on the manometry catheter, interpretation of findings, and relevance in clinical practice specific to the evaluation of non-cardiac chest pain, chronic cough, and rumination syndrome.

    View details for DOI 10.1111/nmo.13861

    View details for PubMedID 32391594

  • Long-term outcomes of per-oral endoscopic myotomy compared to laparoscopic Heller myotomy for achalasia: a single-center experience. Surgical endoscopy Podboy, A. J., Hwang, J. H., Rivas, H., Azagury, D., Hawn, M., Lau, J., Kamal, A., Friedland, S., Triadafilopoulos, G., Zikos, T., Clarke, J. O. 2020

    Abstract

    INTRODUCTION: Many centers have reported excellent short-term efficacy of per-oral endoscopic myotomy (POEM) for the treatment of achalasia. However, long-term data are limited and there are few studies comparing the efficacy of POEM versus Heller Myotomy (HM).AIMS: To compare the long-term clinical efficacy of POEM versus HM.METHODS: Using a retrospective, parallel cohort design, all cases of POEM or HM for achalasia between 2010 and 2015 were assessed. Clinical failure was defined as (a) Eckardt Score>3 for at least 4weeks, (b) achalasia-related hospitalization, or (c) repeat intervention. All index manometries were classified via Chicago Classification v3. Pre-procedural clinical, manometric, radiographic data, and procedural data were reviewed.RESULTS: 98 patients were identified (55 POEM, 43 Heller) with mean follow-up of 3.94years, and 5.44years, respectively. 83.7% of HM patients underwent associated anti-reflux wrap (Toupet or Dor). Baseline clinical, demographic, radiographic, and manometric data were similar between the groups. There was no statistical difference in overall long-term success (POEM 72.7%, HM 65.1% p=0.417, although higher rates of success were seen in Type III Achalasia in POEM vs Heller (53.3% vs 44.4%, p<0.05). Type III Achalasia was the only variable associated with failure on a univariate COX analysis and no covariants were identified on a multivariate Cox regression. There was no statistical difference in GERD symptoms, esophagitis, or major procedural complications.CONCLUSION: POEM and HM have similar long-term (4-year) efficacy with similar adverse event and reflux rates. POEM was associated with greater efficacy in Type III Achalasia.

    View details for DOI 10.1007/s00464-020-07450-6

    View details for PubMedID 32157405

  • Changes in high-resolution manometric diagnosis over time: implications for clinical decision-making. Diseases of the esophagus : official journal of the International Society for Diseases of the Esophagus Triadafilopoulos, G., Kamal, A., Zikos, T., Nguyen, L., Clarke, J. O. 2020

    Abstract

    Although High resolution esophageal manometry (HRM) is the gold standard to assess esophageal motility, little is known about the stability of the manometric diagnosis over time and its implications for management. To assess the stability and usefulness of repeat HRM in patients presenting with esophageal symptoms over time we performed this retrospective study of patients with esophageal symptoms. Medical records, questionnaires, and HRM tracing were independently reviewed using the Chicago classification. The primary objective was to assess the stability of the manometric diagnosis over time; secondary objective was its change (positive or negative). At least one repeat study was performed in 86 patients (36% women, ages 20-86, with mild to moderate symptoms), while 26 had a third procedure. Mean intervals between studies were 151.6months (for baseline v. first study) and 130.8months (for second to third study). Of the 27 patients initially with a normal study, 11 changed (five had esophago-gastric junction outflow obstruction [EGJOO], two diffuse esophageal spasm [DES], one jackhammer esophagus [JE], and three ineffective esophageal motility [IEM] [41% change]). Of the 24 patients with initial EGJOO, only nine retained it (65.2% change). Of nine patients with initial DES, four changed (44.4% change). Similarly, different diagnosis was seen in 7 of 24 initial IEM patients (22.7% change). Only one patient had achalasia initially and this remained stable. Additional changes were noted on a third HRM. Fluidity in the HRM diagnosis over time questions its validity at any timepoint and raises doubts about the need for intervention.

    View details for DOI 10.1093/dote/doz094

    View details for PubMedID 31909786

  • Diagnosis of gastroesophageal reflux: an update on current and emerging modalities. Annals of the New York Academy of Sciences Ang, D., Lee, Y. Y., Clarke, J. O., Lynch, K., Guillaume, A., Onyimba, F., Kamal, A., Gyawali, C. P. 2020

    Abstract

    Gastroesophageal reflux disease (GERD) is a common condition characterized by troublesome symptoms or esophageal mucosal lesions attributed to excessive esophageal acid exposure. Various pathophysiological mechanisms account for GERD, including impaired esophageal peristalsis and anatomical or physiological defects at the esophagogastric junction (EGJ). Endoscopy identifies GERD complications and detects potential alternative diagnoses. However, if symptoms persist despite proton pump inhibitor therapy, functional esophageal tests are useful to characterize reflux burden and define the symptom association profile. Ambulatory pH or pH-impedance monitoring measures the 24-h acid exposure time, which remains the most reproducible reflux metric and predicts response to antireflux therapy. Apart from identifying peristaltic dysfunction, esophageal high-resolution manometry defines the morphology and contractile vigor (EGJ-CI) of the EGJ. Novel metrics obtained from pH-impedance monitoring include the postreflux swallow-induced peristaltic wave index and mean nocturnal baseline impedance, which augment the diagnostic value of pH-impedance testing. Mucosal impedance can also be recorded using a probe inserted through a gastroscope, or a novel balloon catheter with arrays of impedance electrodes inserted following sedated endoscopy. The latest developments in functional esophageal tests define the GERD phenotype based on pathogenesis, reflux exposure, structural or motility disorders, and symptom burden, facilitating appropriate treatment.

    View details for DOI 10.1111/nyas.14369

    View details for PubMedID 32428279

  • Development of a Preliminary Question Prompt List as a Communication Tool for Adults With Gastroesophageal Reflux Disease: A Modified Delphi Study. Journal of clinical gastroenterology Kamal, A., Katzka, D. A., Achkar, E., Carlson, D., Clarke, J., Fass, R., Gyawali, C. P., Patel, D., Penagini, R., Rezaie, A., Roman, S., Savarino, E., Shaheen, N. J., Triadafilopoulos, G. 2020

    Abstract

    Question prompt lists (QPLs) are structured sets of disease-specific questions intended for patient use, encouraging patients to ask questions to facilitate their consultation with their physician.The aim of this study was to develop a QPL specific to adults with gastroesophageal reflux disease (GERD), created by esophageal experts.The QPL content (78 questions) was derived through a modified Delphi method consisting of 2 rounds. In round 1, 18 esophageal experts provided 5 answers to the prompt "What you wish your patients would ask" and "What questions do patients often not ask, that I wish they would ask?" In round 2, the experts rated each question on a 5-point Likert scale, and responses rated as "essential" or "important," determined by an a priori threshold of ?4.0, were accepted for the QPL.Twelve esophageal experts participated. Of 143 questions from round 1, 110 (76.9%) were accepted for inclusion in the QPL, meeting a median value of ?4.0, and, subsequently, it reduced to 78, minimizing redundancy. Median values ranged between 4.0 and 5.0, with the highest agreement median (5.0) for questions asking dosing and timing of proton pump inhibitor therapy, and surveillance in Barrett's. Questions were categorized into the following categories: "What does this illness mean," "lifestyle modifications," "general treatment," "treatment with proton pump inhibitors," "What I should expect for my future," and "Barrett's." The largest number of questions covered lifestyle modifications (21.8%), with the highest agreement median (5.0) for "How helpful are lifestyle modifications in GERD?"A preliminary GERD-specific QPL, the first of its kind, was developed by esophageal experts. Modification after more patient consultation and feedback is planned in subsequent versions to create a GERD-QPL for eventual use in clinical gastroenterology.

    View details for DOI 10.1097/MCG.0000000000001300

    View details for PubMedID 31985713

  • The Association Between Gastroparesis and Slow Transit Constipation as Seen by Wireless Motility Capsule (WMC) Radetic, M., Kamal, A., Rouphael, C., Cline, M. LIPPINCOTT WILLIAMS & WILKINS. 2019: S692?S693
  • Gastric per-oral endoscopic myotomy: Current status and future directions WORLD JOURNAL OF GASTROENTEROLOGY Podboy, A., Hwang, J., Nguyen, L. A., Garcia, P., Zikos, T. A., Kamal, A., Triadafilopoulos, G., Clarke, J. O. 2019; 25 (21): 2581?90
  • Under Pressure: Do Volume-Based Measurements Define Rectal Hyposensitivity in Clinical Practice? DIGESTIVE DISEASES AND SCIENCES Kamal, A. N., Garcia, P., Clarke, J. O. 2019; 64 (5): 1062?63
  • Under Pressure: Do Volume-Based Measurements Define Rectal Hyposensitivity in Clinical Practice? Digestive diseases and sciences Kamal, A. N., Garcia, P., Clarke, J. O. 2019

    View details for PubMedID 30963367

  • High Prevalence of Slow Transit Constipation in Patients With Gastroparesis JOURNAL OF NEUROGASTROENTEROLOGY AND MOTILITY Zikos, T. A., Kamal, A. N., Neshatian, L., Triadafilopoulos, G., Clarke, J. O., Nandwani, M., Nguyen, L. A. 2019; 25 (2): 267?75

    View details for DOI 10.5056/jnm18206

    View details for Web of Science ID 000464525700012

  • High Prevalence of Slow Transit Constipation in Patients With Gastroparesis. Journal of neurogastroenterology and motility Zikos, T. A., Kamal, A. N., Neshatian, L., Triadafilopoulos, G., Clarke, J. O., Nandwani, M., Nguyen, L. A. 2019

    Abstract

    Background/Aims: Current evidence suggests the presence of motility or functional abnormalities in one area of the gastrointestinal tract increases the likelihood of abnormalities in others. However, the relationship of gastroparesis to chronic constipation (slow transit constipation and dyssynergic defecation) has been incompletely evaluated.Methods: We retrospectively reviewed the records of all patients with chronic dyspeptic symptoms and constipation who underwent both a solid gastric emptying scintigraphy and a highresolution anorectal manometry at our institution since January 2012. When available, Xray defecography and radiopaque marker colonic transit studies were also reviewed. Based on the gastric emptying results, patients were classified as gastroparesis or dyspepsia with normal gastric emptying (control group). Differences in anorectal and colonic findings were then compared between groups.Results: Two hundred and six patients met the inclusion criteria. Patients with gastroparesis had higher prevalence of slow transit constipation by radiopaque marker study compared to those with normal emptying (64.7% vs 28.1%, P = 0.013). Additionally, patients with gastroparesis had higher rates of rectocele (88.9% vs 60.0%, P = 0.008) and intussusception (44.4% vs 12.0%, P = 0.001) compared to patients with normal emptying. There was no difference in the rate of dyssynergic defecation between those with gastroparesis vs normal emptying (41.1% vs 42.1%, P = 0.880), and no differences in anorectal manometry findings.Conclusions: Patients with gastroparesis had a higher rate of slow transit constipation, but equal rates of dyssynergic defecation compared to patients with normal gastric emptying. These findings argue for investigation of possible delayed colonic transit in patients with gastroparesis and vice versa.

    View details for PubMedID 30870880

  • Gastric per-oral endoscopic myotomy: Current status and future directions. World journal of gastroenterology Podboy, A., Hwang, J. H., Nguyen, L. A., Garcia, P., Zikos, T. A., Kamal, A., Triadafilopoulos, G., Clarke, J. O. 2019; 25 (21): 2581?90

    Abstract

    Gastroparesis, or symptomatic delayed gastric emptying in the absence of mechanical obstruction, is a challenging and increasingly identified syndrome. Medical options are limited and the only medication approved by the Food and Drug Administration for treatment of gastroparesis is metoclopramide, although other agents are frequently used off label. With this caveat, first-line treatments for gastroparesis include dietary modifications, antiemetics and promotility agents, although these therapies are limited by suboptimal efficacy and significant medication side effects. Treatment of patients that fail first-line treatments represents a significant therapeutic challenge. Recent advances in endoscopic techniques have led to the development of a promising novel endoscopic therapy for gastroparesis via endoscopic pyloromyotomy, also referred to as gastric per-oral endoscopic myotomy or per-oral endoscopic pyloromyotomy. The aim of this article is to review the technical aspects of the per-oral endoscopic myotomy procedure for the treatment of gastroparesis, provide an overview of the currently published literature, and outline potential next directions for the field.

    View details for DOI 10.3748/wjg.v25.i21.2581

    View details for PubMedID 31210711

    View details for PubMedCentralID PMC6558440

  • Inflammatory Bowel Disease and Irritable Bowel Syndrome: What to Do When There Is an Overlap INFLAMMATORY BOWEL DISEASES Kamal, A., Padival, R., Lashner, B. 2018; 24 (12): 2479?82

    View details for DOI 10.1093/ibd/izy277

    View details for Web of Science ID 000456677100001

    View details for PubMedID 30169572

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