ENDOSCOPY
Educational Objectives
| The goal of this program is to improve aspects of endoscopic surgery and management of esophageal cancer. After hearing and
assimilating this program, the clinician will be better able to:
|
 | 1. Review the guidelines recommended for patients undergoing low- and high-risk procedures who are on
anticoagulation therapy, low molecular weight heparin, aspirin, or nonaspirin antiplatelet agents.
|
| 2. Describe the effects of electrocautery in a patient with a pacemaker or automated internal cardiac defibrillator.
|
| 3. Discuss the advantages and developmental hurdles of natural orifice transluminal endoscopic surgery (NOTES).
|
| 4. Recognize factors to be considered in the treatment of esophageal cancer.
|
| 5. Describe advantages and disadvantages of treatment options for esophageal cancer.
|
Faculty Disclosure
In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty and members of the planning
committee to disclose relevant financial relationships within the past 12 months that might create any personal conflicts
of interest. Any identified conflicts were resolved to ensure that this educational activity promotes quality in health
care and not a proprietary business or commercial interest. For this program, the following has been disclosed: Dr. Johnson
has received an education grant from Ethicon, research support from USGI, Olympus, and Wolf, and is a consultant for
NDO. Dr. Rothstein receives research support from Bard, NDO, Safestitch, Ethicon, and Barrx, and is a consultant for Ethicon,
Boston Scientific, Olympus, and NDO. The planning committee reported nothing to disclose.
Acknowledgements
Dr. Johnson was recorded at the 32nd Annual Texas Program, held September 14-16, 2007, in Grapevine, TX, and
sponsored by the Texas Society for Gastroenterology and Endoscopy, the American College of Gastroenterology, and
the Society for Gastroenterology Nurses and Associates (SGNA) Texas Regional Societies. Drs. Swanstrom and
Rothstein were recorded at the Esophageal Conference, held September 6-7, 2007, in Omaha, NE, and sponsored by
the Esophageal Center, Creighton University Medical Center, and the Continuing Education Division, Creighton
University School of Medicine. The Audio-Digest Foundation thanks the speakers and the sponsors for their cooperation
in the production of this program.
| PREOPERATIVE EVALUATION OF PATIENTS FOR ENDOSCOPY —David A. Johnson, MD, Professor of Medicine
and Chief of Gastroenterology, Eastern Virginia Medical School, Norfolk, VA
|
| Electrocautery: electric current converted to heat, which passes through tissue; when applying grounding pad, place in
area that dissipates heat through good blood supply; in presence of pacemaker—injuries can occur from damage to or reprogramming
of pulse generator; also induces rise in capture threshold, which can cause ventricular and other cardiac
dysrhythmias; creates electromagnetic fields 60 V/m, which can cause inhibition of pacemaker (pacemaker sensors
highly sensitive; can detect ≤0.1 V/m); permanent damage possible; ensure that not near immediate area of generator; if
energy exceeds protective circuits, interferes with pacemaker; voltage shunting away from generator goes down electrode
pathway not meant to carry electric current (meant to carry cardiac conduction current); in internal cardiac defibrillators
(ICDs)—electrocautery current in proximity to heart interpreted as R wave, stimulating arrhythmias and eliciting shock;
no evidence that electrocautery should not be used; monitoring particularly important if ICD inactivated (routinely done
in patients undergoing therapeutic endoscopy); if anything in area of hardware (eg, distal esophagus, proximal stomach,
splenic flexure), critical to avoid long bursts (using bipolar electrocautery tends to shunt energy away)
|
| Anticoagulation: when anticoagulation stopped, probability of injury depends on preexisting condition; with mechanical
heart valves, risk for embolism striking with uninterrupted coagulation cascade; goes from standard without anticoagulation
of 4/patient-year to 4-fold reduction if anticoagulated, but still relative to level of anticoagulation; risk also varies
with type of valve and location; caged-ball or disk-type valves have higher risk; aortic and mitral locations also have
higher risk; previous embolic event likely to recur if anticoagulation stopped; atrial fibrillation (AF) another risk factor;
low-risk procedures—current guidelines state that no adjustments in anticoagulation warranted, irrespective of condition;
avoid elective procedures when above therapeutic range; high-risk procedure and low-risk condition—stop warfarin
3 to 5 days before procedure and individualize preprocedural international normalized ratio (INR); high-risk procedure
and high-risk condition—stop warfarin 3 to 5 days before procedure and individualize preprocedural heparin, whether
bridge therapy necessary or not; discontinue heparin 4 to 6 hr before procedure; resume heparin 2 to 6 hr after procedure;
unfractionated heparin (UFH)—commonly used for prophylaxis and treatment of cardiac ischemic events and prevention
of thromboembolic events
|
| Low molecular weight heparin (LMWH): eg, enoxaparin (Lovenox); deals with activating and antithrombin-inhibiting
factor Xa; differs from heparin in its greater selectivity for coagulation cascade and lower affinity for antithrombin,
making it more predictable and less independent upon clearance; partial thromboplastin time (PTT) not reflective of
enoxaparin effect (not useful in monitoring); less associated with bleeding and heparin-induced thrombocytopenia (HIT)
syndrome; duration of effect 12 hr; standard or weight-based doses; protamine used for overdose; low-risk procedure—
no adjustments necessary, irrespective of condition; high-risk procedure with low-risk condition—discontinue LMWH
for 8 hr, and individualize when to restart; high-risk procedure with high-risk condition—LMWH used as bridge; stop
warfarin 3 to 5 days before, and use weight-based dosing for enoxaparin (mg/kg q12h), discontinue for 8 hr, and individualize
when to restart
|
| Aspirin: interferes with platelet cyclooxygenase and thromboxane A2 ; limited data on standard doses show no increased
risk for procedural complications, ie, gastrointestinal (GI) bleeding; recommendations—in absence of preexisting bleeding
disorders, endoscopic procedures acceptable for patients on aspirin and nonsteroidal anti-inflammatory drugs
(NSAIDs) in standard doses; however, routine practice to stop for 7 days before procedure
|
| Nonaspirin antiplatelet agents: clopidogrel (Plavix) and glycoprotein (GP) IIb/IIIa receptor inhibitors; bleeding
time, particularly with clopidogrel, extends 7 days; recovery of platelet function in 3 to 5 days but may take up to 7 to 10
days; parenteral GPIIb/IIIa receptor inhibitors—2 classes; includes abciximab (ReoPro; monoclonal antibody) and peptide
receptor antagonists eptifibatide (Integrilin) and tirofiban (Aggrastat); given by continuous infusion; seen particularly
in patients with cardiac stents and acute intervention; duration of action for abciximab 24 hr (4 hr for eptifibatide
and tirofiban); low-risk procedures, including colonoscopy with biopsy—no adjustments, irrespective of condition; high-
risk procedures with high-risk conditions—whether to discontinue not determined; if choosing to stop, stop for 7 to 10
days (duration of activity); if patient on aspirin and clopidogrel, do not discontinue both; possibly stop clopidogrel, first
checking with cardiologist; individualize when to restart; if patient on GPIIb/IIIa receptor inhibitors, discontinue infusion,
then wait 4 hr if on short-acting agents (24 hr for abciximab); if patient actively bleeding, transfuse platelets and
give 1-deamino-8-D-arginine vasopressin (DDAVP; desmopressin) to enhance platelet function; study—looked at cardiac
patients on aspirin who presented with acute bleeding; randomized to resume aspirin or placebo; recurrent ulcer
bleeding slightly higher for those on aspirin (not statistically different); event rates increased by 5-fold (statistically significant)
if aspirin stopped; consider cardiovascular risk in decision making; possible to perform endoscopic therapy in
high-risk patients on antiplatelet therapy; risk for bleeding should be balanced with risk for thromboembolic events; evidence
for reducing risk for postpolypectomy bleeding by withholding antiplatelet agents during elective colonoscopy and
polypectomy marginal at best; endoscopists who consider cardiovascular risk should defer elective procedures in patients
in whom high risk present (eg, recent pacemaker or cardiovascular stent); if possible, defer 1 yr, using bridge therapy
with aspirin; discontinuation of aspirin and nonsteroidal agents not mandated for most endoscopic procedures (no evidence
to suggest adverse influence)
|
| Antibiotics: disadvantages—include anaphylactic reactions (more with penicillin than cephalosporins) in range of 15 to
25/million as well as emerging resistance to “super bugs” (eg, vancomycin-resistant enterococci [VRE], methicillin-resistant
Staphylococcus aureus [MRSA]); new guidelines state that antibiotics for prevention of gastrointestinal (GI)-related
infectious endocarditis not recommended; if choosing to give antibiotics (eg, infected biliary tree), must be effective
against Enterococcus
|
| NATURAL ORIFICE TRANSLUMINAL ENDOSCOPIC SURGERY (NOTES)—Lee Swanstrom, MD, Clinical Professor
of Surgery, Oregon Health Sciences University, and Director, Division of Minimally Invasive Surgery, Legacy Health System,
Portland, OR
|
| Evolution of GI surgery: surgery becoming less invasive; flexible endoscopy has gone from purely diagnostic to advanced
therapeutic modality; endoscopic transluminal surgery merger of flexible endoscopy and laparoscopic surgery
|
| Natural orifice transluminal endoscopic surgery (NOTES): less invasive, less painful, and less tissue trauma;
less costly by turning inpatient procedures into outpatient ones; better cosmesis; public demand for less invasive surgery;
study—looked at whether patients preferred to have gallbladder removed by flexible endoscopy through mouth as
NOTES procedure or by laparoscopy; procedures explained and risks and recovery defined; majority chose NOTES procedure
because of perception that less painful, less risky, less costly, and quicker recovery, although would require more
skill; 80% still preferred procedure, even if risk greater; possible procedures amenable to NOTES—tubal ligation, staging
procedures, gastrojejunostomy for obesity or bypasses for obstructive cancers, appendectomy, bariatric surgery, hernia
repair, cholecystectomy, and more; essentially replicating laparoscopic procedures with flexible endoscopy; NOTES being
practiced now, including peritoneoscopy, pregastrectomy as cancer staging procedure, single-port cholecystectomy
(uses NOTES instrumentation), transvaginal cholecystectomy, and transgastric cholecystectomy; developmental
hurdles—ideal scope configuration, safe energy sources, harmonic scalpels and stapling devices, crude and primitive instrumentation,
device complexity and cost (devices prototypic and not user-friendly), and appropriate position of patient;
flexible endoscopes designed for internal use in GI tract (small size and extreme flexibility ideal, but not for NOTES procedure);
fourth-generation devices being developed, eg, Cobra device that allows surgeon to triangulate and have independent
movement of instrumentation, with fixed and steady visualization; due to complexity of instruments, possibly
necessary to have computer interpositioned between surgeon and endoscope to control complex maneuvers (robotic interface);
tissue approximation devices also being developed; other hurdles—developmental issues; determining ideal
procedure; how to collect outcomes data; credentialing; reimbursement issues; what happens when public demands this
|
| Training and credentialing: National Orifice Surgery Consortium for Assessment and Research (NOSCAR) stresses
performance as team (gastroenterologist and surgeon) but not feasible (difficulty of matching schedules); general surgeons
require training if appendectomies and cholecystectomies common procedures; general gastroenterologists likely
will use NOTES for diagnostic procedures but not for surgery; endoscopic surgery specialists new program at Mayo
Clinic; requires new teaching techniques, mentorships, ongoing education, new fellowships, and virtual reality simulations
|
| ENDOSCOPIC THERAPY FOR ESOPHAGEAL CANCER —Richard I. Rothstein, MD, Professor of Medicine and
Chief, Section of Gastroenterology and Hepatology, Dartmouth Medical Center, Lebanon, NH
|
| Treatment of esophageal cancer: options include surgery, radiation therapy, chemotherapy, endoscopic treatment,
and supportive measures; factors to consider—stage of tumor, symptoms, location of tumor, overall goals of therapy, age
and functional status of patient, and tumor histology; staging key to management; also depends on kind of tumor; because
management of esophageal cancer depends on size and location of tumor and patient’s fitness, surgery or endoscopic
therapy recommended treatment for early disease (if extremely early and amenable); for locally advanced disease, stents,
radiotherapy and/or chemotherapy, or ablative therapy; in metastatic disease, stenting for palliation, chemotherapy, radiation
therapy, or supportive therapy; endoscopic therapy options include ablative measures (eg, laser, argon plasma coagulation
[APC], bipolar electrocoagulation [BiCAP]), injection modalities (eg, alcohol), photodynamic therapy (PDT),
intraesophageal brachytherapy, radiofrequency, and cryotherapy (for early lesions); mechanically, stents used; also, dilation
of tumor and placement of percutaneous endoscopic gastrostomy (PEG) tubes
|
| Laser: has evolved to more portable units, although presently, no longer used as much; allows opening of occluded lumen
to deliver therapy and allow patient to eat ; indications—exophytic tumors (two-thirds of tumors), particularly in high locations;
also used for tumor ingrowth in stents; typically outpatient procedure; success ≈90% in 2 sessions; repeatable; in
expert hands, low complication rate of 0% to 5%; contraindications—nonexophytic tumors and tumors extrinsic to
esophagus; also in presence of tracheoesophageal fistula; due to tumor regrowth, performed every 4 to 16 wk; lasers not
readily available; relatively expensive to set up; outcomes—initial relief of dysphagia occurs in 70% to 90% of patients
requiring 2 sessions (in general); about one-third able to return to eating solid food and two-thirds to semisolid and solid
food; dysphagia-free interval of 1 to 4 mo; complications include perforation (3%-8%) and fistula formation (≈6%); in 2
randomized controlled trials (RCTs) comparing laser with stent, no difference in quality of life and survival
|
| Esophageal dilation: improvement seen in ≈75% of patients; effect usually short-lived (12 days to 4 wk); complications
of standard dilation in patients with tumors 2.5% to 10%, mostly excessive bleeding requiring transfusion; also
perforation (especially if not wire-guided); no RCTs comparing different dilators; all seem to have comparable outcomes;
indicated for palliation, not durable
|
| PDT: role in advanced carcinoma limited; causes photosensitivity; overall results comparable to laser in establishing patency
and palliation
|
| Injection modalities: injectants include alcohol, sclerosants, antineoplastic agents, and gene therapy; simple technique but
poorly controlled; requires multiple sessions; duration of effect short for most agents (<1 mo); complications uncommon
but include perforation; alcohol—most studied; for soft exophytic tumors, especially those very proximal to
esophagus (eg, near cricopharyngeus) where difficult to place stent without discomfort to patient; in 9 case series involving
154 patients, 80% to 100% dysphagia relief; effective, but duration of effect short; mediastinitis and tracheoesophageal
fistulas occur in 2% of patients; causes pain and ulcerates esophagus; must be repeated
|
| Ablative therapies: limited data on use of APC; must increase to 100 W (from 50 W typically used in other lesions)
|
| Stents: advantages—outpatient procedure; requires minimal preparation; technically easy to perform; low mortality;
technical success almost 100%; dysphagia relief in almost 70%; able to treat tracheoesophageal fistulas and extrinsic
tumors; disadvantages—costly; tumor overgrowth occurs after time; further intervention necessary in one-third of patients;
repeated stenting necessary; not ideal for high locations in esophagus; increase in risk described after chemoradiation;
stents migrate; early stents—made of plastic, had small-diameter lumens, and required dilation of tumor before
placement; could result in perforation or excessive bleeding; self-expanding metal stents (SEMS)—small size; inserted
via scope or along guide wire; expands when released; differ in radial force that pushes against tumor, flexibility and
maneuverability, method by which stent shortens, and delivery systems; no significant differences found in trials; expensive;
better than plastic stents for treating fistulae; complications—perforation in 1% to 2%; airway compromise;
malposition; aspiration and even pneumonitis or pneumonia; fever from pressure on tumor in mediastinum; early complications
include bleeding and chest pain; late complications include migration, reobstruction, food impaction, and
bleeding; also gastroesophageal reflux disease (GERD) and aspiration; antireflux devices used to decrease symptoms;
PEG after stent placement—caution necessary when pulling PEG tube through; use small-caliber PEG tube; can modify
internal bolster by cutting slits so it becomes more malleable; self-expanding plastic stents—Polyflex stent used for
malignant and benign disease; in study of 33 patients who received Polyflex stents for malignant obstruction, patients
lived mean of 148 days, with complications (migration and tumor overgrowth) seen in 21% of patients; dysphagia
score improved; advantages include ability to place into occluded metal stent or to remove when used in benign disease;
conclusions—SEMS preferred option for palliation
|
Suggested Reading
Allori AC et al: Natural orifice transluminal endoscopic surgery: lessons learned from the laparoscopic revolution. Arch Surg
143:333, 2008; Blom D et al: Surgery, radiotherapy, and chemotherapy in carcinoma of the esophagus. Curr Opin Gastroenterol
16:392, 2000; Blom D: Surgical management of esophageal malignancy. Curr Gastroenterol Rep 5:192, 2003; Gill IS
et al: Single port transumbilical (E-NOTES) donor nephrectomy. J Urol 180:637, 2008; Kothari SN et al: Best Poster
Award. A comparison of thromboembolic and bleeding events following laparoscopic gastric bypass in patients treated with prophylactic
regimens of unfractionated heparin or enoxaparin. Am J Surg 194:709, 2007; Lanas A et al: Risk of upper gastrointestinal
ulcer bleeding associated with selective cyclo-oxygenase-2 inhibitors, traditional non-aspirin non-steroidal anti-
inflammatory drugs, aspirin and combinations. Gut 55:1731, 2006; Litle VR et al: Photodynamic therapy as palliation for
esophageal cancer: experience in 215 patients. Ann Thorac Surg 76:1687, 2003; Margolis M et al: Percutaneous endoscopic
gastrostomy before multimodality therapy in patients with esophageal cancer. Ann Thorac Surg 76:1694, 2003; Martin RC et
al: The use of self-expanding silicone stents in esophagectomy strictures: less cost and more efficiency. Ann Thorac Surg 86:436,
2008; May A et al: Local endoscopic therapy for intraepithelial high-grade neoplasia and early adenocarcinoma in Barrett's oesophagus:
acute-phase and intermediate results of a new treatment approach. Eur J Gastroenterol Hepatol 14:1085, 2002; Pech
O et al: Long-term results and risk factor analysis for recurrence after curative endoscopic therapy in 349 patients with high-
grade intraepithelial neoplasia and mucosal adenocarcinoma in Barrett's oesophagus. Gut 57:1200, 2008; Pennathur A et al:
Polyflex expandable stents in the treatment of esophageal disease: initial experience. Ann Thorac Surg 85:1968, 2008; Sharma
P: Current status of ablative therapies in esophageal disorders. Curr Gastroenterol Rep 3:219, 2001.
|
