ORIGINAL ARTICLE
Downhill Esophageal Varices: A Prevalent Complication of Superior Vena Cava Obstruction From Benign and Malignant Causes Yoel Siegel, MD,* Erica Schallert, MD,† and Russ Kuker, MD* Objective: Downhill esophageal varices (DEV) usually develop secondary to superior vena cava (SVC) obstruction. Downhill esophageal varices have been less well characterized compared to uphill varices. The aim of the study was to characterize the anatomy and etiology of DEV by contrastenhanced computed tomography. Methods: Patients with SVC obstruction were included in the study. Downhill esophageal varices were defined as discrete esophageal submucosal or mucosal vessels. Ten random computed tomographic scans were assessed as controls. Results: Downhill esophageal varices were seen in 11 of 36 patients. Three types of varices were observed. Between 1 and 6 varices were seen in each patient with a diameter of 1 to 5 mm. Conclusions: Downhill esophageal varices can be seen in 30% of patients with SVC obstruction. They have several patterns and are mostly systemic-to-systemic collaterals. The most common etiology associated with DEV is renal failure. Downhill esophageal varices are of small caliber, this may in part account for less frequent bleeding compared to uphill varices. Key Words: superior vena cava obstruction, downhill esophageal varices, end-stage renal disease, lung cancer (J Comput Assist Tomogr 2015;39: 149–152)
D
ownhill esophageal varices (DEV) are venous collateral pathways that usually develop with superior vena cava (SVC) obstruction. Downhill esophageal varices are distinguished from uphill varices (UEV) which are caused by a different etiology, namely portal hypertension. Downhill varices were first coined in the radiology literature in 1964 by Felson and Lessure1 and diagnosed by barium studies. However, with the advent of crosssectional imaging, computed tomography (CT) has become the main tool for diagnosis and demonstrated these vessels as early as 1984.2 The ability of CT to demonstrate these collateral pathways can be affected by technical factors related to the methods of contrast injection. Some of the most common pathways reported in the radiological literature are the mediastinal, esophageal, and diaphragmatic venous plexuses, azygos-hemiazygosaccessory hemiazygos system, and the lateral thoracic and superficial thoracoabdominal venous plexuses.3–6 Although UEV have received much attention in the medical literature, DEV have been less described and characterized. This is largely because morbidity and mortality related directly to DEV are less common than with UEV. Although hemorrhage From the *Thoracic and Abdominal Imaging Sections, Jackson Memorial Hospital, University of Miami Miller School of Medicine, Miami, FL; and †Department of Pediatric Radiology, Texas Children's Hospital, Baylor College of Medicine, Houston, TX. Received for publication July 25, 2014; accepted October 16, 2014. Reprints: Yoel Siegel, MD, Thoracic and Abdominal Imaging Sections, Jackson Memorial Hospital, University of Miami School of Medicine, JMH WW 279, 1611 NW 12th Ave, Miami, FL 33136 (e‐mail: [email protected]). The authors declare no conflict of interest. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
is more common with UEV, there have been multiple reports in the literature describing esophageal hemorrhage from DEV.7–10 Furthermore, it has been proposed that approximately 8% of patient with DEV tend to have upper gastrointestinal bleeds.11 To date, the prevalence of DEV has not been fully characterized in the literature. Also, the etiology of the SVC obstruction causing DEV has not been fully studied. In the previous century, infection and later malignancy were responsible for most of SVC syndromes; however, with the increasing use of catheters and venous indwelling devices such as pacemakers, the incidence of obstruction secondary to benign causes is rising.12 Because the use of central venous access is very common, it is possible that a concurrent rise in associated complications such as SVC obstruction is also occurring, resulting in an increase in incidence of DEV. The aim of the study was to characterize DEV, their morphology, and the causes of associated SVC obstruction.
MATERIALS AND METHODS The study was approved by the institutional review board. An archive search within our institution's PACS system was performed between August 2008 and February 2014, using key words such as superior vena cava obstruction and superior vena cava occlusion. Patients 18 years and older were included in the study, allowing a uniform technique of IV contrast administration and CT scan technique. The patients included in the study had contrast-enhanced CT scans which demonstrated complete or near-complete SVC obstruction. A set definition of near-complete occlusion is not established as there are no precise guidelines available. Hence, to define near-complete occlusion, an arbitrary threshold of 0.2 cm2 or less as measured by a free hand ROI tool of patent SVC lumen was considered near occlusion. In addition to the patients included in the study, 10 randomly selected CT scans of adults were assessed as a control group. All patients were scanned on one of 3 CT scanner types including a 4-channel MX 8000 (Philips Medical System, Best, the Netherlands), 64-channel Somatom Sensation, and 128-channel Definition DS (Siemens Medical Solutions, Forchheim, Germany). Types of contrast intravenous included Omnipaque 350 or 300 (GE Healthcare Princeton, NJ) and Optiray 320 (Mallinckrodt, St Louis, Mo). The rate of injection varied according to the indication for the scan ranging from 2 to 3.5 mL/s. The location at which the SVC was occluded was divided into the following categories: above the level of the azygos vein, below or at the level of the azygos vein or throughout the entire SVC. Downhill esophageal varices were defined as discrete submucosal esophageal tubular enhancing structures indicating venous vessels and were characterized according to course and diameter. The images assessed on the PACS were in the axial plane with thickness of 1.5 mm and reformatted in sagittal and coronal planes.
RESULTS Thirty-six patients were included in the study; 21 men and 15 women. The age range was 22 to 81 years, the average age
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was 53 years, and the median was 55 years. Twenty-two patients demonstrated complete SVC obstruction, whereas 14 patients demonstrated near-complete SVC obstruction. In 17 of 36 patients, obstruction was directly related to mass effect from tumor burden. Of the non–tumor-related SVC obstructions, 13 patients had end-stage renal disease and 4 had known malignancy without an obstructing mass. In addition, 1 patient had sickle cell disease and 1 coagulopathy leading to chronic obstruction. Downhill esophageal varices were identified in 11 of 36 patients with the following background diseases: end stage renal disease (n = 6), chest mass (n = 3), sickle cell disease (n = 1), and indwelling catheter with history of colon cancer (n = 1). The number of varices identified in each patient was between 1 and 6 vessels. The range of variceal diameters was between 1 and 5 mm; however, most of the patients had varices between 2 and 3 mm. Six patients had larger varices that ranged from 3 to 5 mm (only 1 patient had 5-mm varix diameter). Three distinct patterns of DEV were identified. Pattern 1 represented varices extending from the upper third to the middle third of the esophagus. Pattern 2 included varices extending from the middle third to the lower third of the esophagus. Pattern 3 contained those varices starting in the upper third and continuing into the lower third of the esophagus (Figs. 1–4). Some of the patients demonstrated small, focal, or very short tubular enhancing structures in the mucosa/submucosa of the esophagus that may be small esophageal vessels or mucosal enhancement. However, as this finding was also seen in some of the scans in the control group, it may not represent a pathological finding. None of the control CT scans demonstrated the specific 3 patterns of DEV described above. Of the 3 DEV types identified, the largest diameter of 4 mm was seen in pattern 3. The location of obstruction of the SVC and the associated types of varices can be seen in Tables 1 and 2. Evaluation of the drainage of the varices showed that most of the varices connected to adjacent mediastinal veins as part of a network of vessels. There was no clear direct connection between the varices and the portal system. However, at least 1 patient with DEV had a complex venous plexus in the paraesophageal and left abdominal region that did drain into the portal system. In some of the cases, the drainage below the diaphragm was to the hepatic
FIGURE 1. Schematic drawing of the types of DEV. The esophagus is divided into 3 regions as follows: upper third, middle third, and lower third. Three types of DEV are depicted. Type 1, Extending from the upper third to the middle third of the esophagus Type 2, Extending from the middle third to the lower third of the esophagus Type 3, Starting in the upper third and continuing into the lower third. Figure 1 can be viewed online in color at www.jcat.org.
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FIGURE 2. Type 1, A 56-year-old man with lung cancer and near-complete obstruction of the SVC. Sagittal MPR image of a contrast enhanced CT show DEV extending from the upper third to the middle third of the esophagus (arrows). The DEV appears discontinuous because of its tortuous course.
veins and the inferior vena cava (Fig. 5); whereas in others, the drainage was not clearly identified. A review of the electronic medical charts did not reveal a gastrointestinal hemorrhage directly attributable to the varices in any of the patients.
DISCUSSION In this study, we evaluated DEV in the setting of SVC obstruction. We found that DEV are relatively common in association with SVC obstruction. In this cohort, DEV were
FIGURE 3. Type 2, A 47-year-old woman with end-stage renal disease on hemodialysis with occlusion of the SVC. Coronal maximal intensity projection (MIP) image of a contrast enhanced CT in bone window demonstrates submucosal esophageal varices (arrow), extending from the mid/upper esophagus to the distal esophagus. © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
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Downhill Esophageal Varices
TABLE 2. Location of SVC Obstruction Obstruction Obstruction Obstruction Involving DEV Type Above Azygos Below Azygos Azygos or All SVC 1 2 3
* * *
* * *
Table 2 shows that no association between the type of DEVand the level of obstruction was found. *indicates that this type of varices was associated with obstruction at the above level.
present in 30% of patients with complete or near-complete SVC obstruction. These veins have a range in size measuring up to 5 mm in diameter. We were able to identify 3 patterns or types of DEV anatomy related to their course. The most common being type 3, where the varix begins in the upper third and continues into the lower third of the esophagus. It has been reported that an obstruction below the azygos vein leads to varices involving the upper third of the esophagus, whereas an obstruction involving the azygos vein would have varices throughout the esophagus.1,10 In this study, we did not find a consistent type of varix about the location of SVC obstruction. This may be due to an overall increase in the venous pressure regardless of the origin of obstruction in the SVC and recruitment of all available collateral channels. Also, it is likely that CT is very sensitive to smaller varices that would otherwise not be clearly identified by other modalities such as barium swallow or direct endoscopic visualization. Drainage of collateral vessels from obstruction of the SVC into the portal system has been described, for example, DEV draining into a plexus that communicates with the coronary vein and thus joining the portal system.10,13,14 In most of the CT scans we reviewed, this communication was not apparent. Rather, the
FIGURE 4. Type 3, A 62-year-old man with end-stage renal disease on hemodialysis with occlusion of the entire SVC. Curved MPR image of a contrast enhanced CT demonstrates submucosal esophageal varices (arrow), beginning in the upper third of the esophagus and continuing into the lower third.
TABLE 1. DEV* Type Characterization DEV Type
Number
Non-Mass/Mass Related SVC Obstruction
1 2 3 Total
2 (20%) 3 (30%) 6 (50%) 11
2/0 2/1 5/1 8/2
*Downhill esophageal varices.
FIGURE 5. A 54-year-old woman with end-stage renal disease and type 2 DEV. The esophageal varix depicted is draining into the confluence of the inferior vena cava and inferior phrenic vein (white arrow) indicating a systemic-to-systemic collateral pathway. Note dilated azygos vein (black arrow).
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most common patterns were systemic-to-systemic venous collateral pathways. We most commonly observed collateral vessels communicating between the DEV and the hepatic veins or the IVC. Laboratory studies have shown that anastomoses exist between the inferior phrenic vein, which drains into the IVC, and the internal mammary and intercostal veins.15 It is therefore likely that these same pathways were seen in our study, that is, the collateral veins drain directly into the IVC without coursing through the portal system. We did, however, see one systemic to portal venous pathway. These observations suggest that DEV are usually not a reversal of the portosystemic pathway seen in UEV, but rather part of a systemic-to-systemic venous pathway in most cases. Complications caused by DEV are not as common as seen in UEV, the most severe being hemorrhage. In our cohort of patients, there was no chart documentation of gastrointestinal bleeding attributable to the varices; although in the literature, approximately 8% of patients with DEV may have upper gastrointestinal bleeds.11 The reason why UEV are more prone to bleeding than DEV is unclear. It may be related to the coagulopathic state of cirrhotic patients. It has also been postulated that UEV are invariably located at the distal esophagus where they are more vulnerable to erosive gastroesophageal reflux and thus to bleeding.16 Another explanation may be related to the vessel diameters. A study by the northern Italian endoscopic club showed that the diameter of UEV correlates with propensity to bleed in patients with cirrhosis, and in that study, a varix more than 4 mm was considered large.17 In our study, most of the varices were smaller than 4 mm and only 1 patient had a varix of 5 mm. This smaller caliber of vessels may be secondary to lower pressure gradients then seen in UEV that bleed. Of interest is that most of the varices in our study were in patients with end-stage renal disease. Patients on hemodialysis have a high rate of central venous narrowing. The cause of this increased risk for venous narrowing is multifactorial and includes among others endothelial injury, turbulent blood flow, and tendency for thrombosis.18 This may explain the high prevalence of SVC obstruction in patients on hemodialysis. In addition, patients on hemodialysis are usually treated for many years. This extended time frame may allow the varices to develop as opposed to patients with malignant causes, where the onset of SVC occlusion may be shorter. One weakness of this study is that we did not correlate the patient's symptoms with the radiological findings. There may be a correlation of the variceal pattern to certain patient presentations. However, the goal of the study was to describe DEV anatomically and the associated causes of SVC obstruction. Possibly a future study can correlate symptoms with certain types of varices. Of all the variety of collateral vessels that have been described and their pathways that result from SVC obstruction, most do not cause significant morbidity and mortality. We did not encounter any patients with proven gastrointestinal hemorrhage. Nevertheless, DEV have the potential for significant complications and may be underappreciated as a source of gastrointestinal hemorrhage. It is important for radiologists and clinicians to be aware of these varices to include DEV as a potential source of gastrointestinal bleed. Also, it seems that the incidence of longterm SVC obstruction will rise as the use of central venous access and instrumentation becomes more frequent and as the life expectancy of cancer patients increases.19 As the number of procedures and patients with SVC obstruction rise, so it is assumed, will the incidence of DEV. In summary, DEV seem to be a relatively common collateral pathway in patients with SVC obstruction. They demonstrate
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multiple patterns of distribution and usually form systemic-tosystemic collateral bypasses. When compared to UEV, DEV are mostly smaller in caliber than UEV which that are more prone to bleed. Downhill esophageal varices are more commonly present in benign causes of SVC obstruction.
REFERENCES 1. Felson B, Lessure AP. “Downhill” varices of the esophagus. Dis Chest. 1964;46:740–746. 2. Hirose J, Takashima T, Susuki M, et al. “Downhill” esophageal varices demonstrated by dynamic computed tomography. J Comput Assist Tomogr. 1984;8:1007–1009. 3. Qanadli SD, El Hajjam M, Bruckert F, et al. Helical CT phlebography of the superior vena cava: diagnosis and evaluation of venous obstruction. AJR Am J Roentgenol. 1999;172:1327–1333. 4. Gosselin MV, Rubin GD. Altered intravascular contrast material flow dynamics: clues for refining thoracic CT diagnosis. AJR Am J Roentgenol. 1997;169:1597–1603. 5. Cihangiroglu M, Lin BH, Dachman AH. Collateral pathways in superior vena caval obstruction as seen on CT. J Comput Assist Tomogr. 2001;25:1–8. 6. Sheth S, Ebert MD, Fishman EK. Superior vena cava obstruction evaluation with MDCT. AJR Am J Roentgenol. 2010;194:W336–W346. 7. Gopaluni S, Warwicker P. Superior vena cava obstruction presenting with epistaxis, haemoptysis and gastro-intestinal haemorrhage in two men receiving haemodialysis with central venous catheters: two case reports. J Med Case Rep. 2009;3:6180. 8. Froilán C, Adán L, Suárez JM, et al. Therapeutic approach to “downhill” varices bleeding. Gastrointest Endosc. 2008;68:1010–1012. 9. Areia M, Romãozinho JM, Ferreira M, et al. “Downhill” varices: a rare cause of esophageal hemorrhage. Ren Esp Enferm Dig. 2006;98:359–361. 10. Pop A, Cutler AF. Bleeding downhill esophageal varices: a complication of upper extremity hemodialysis access. Gastrointest Endosc. 1998;47: 299–303. 11. Papazian A, Capron JP, Rémond A, et al. Upper esophageal varices. Study of 6 cases and review of the literature [in French]. Gastroenterol Clin Biol. 1983;7:903–910. 12. Rice TW, Rodriguez RM, Light RW. The superior vena cava syndrome: clinical characteristics and evolving etiology. Medicine (Baltimore). 2006;85:37–42. 13. Dahan H, Arrivé L, Monnier-Cholley L, et al. Cavoportal collateral pathways in vena cava obstruction: imaging features. AJR Am J Roentgenol. 1998;171:1405–1411. 14. Kapur S, Paik E, Rezaei A, et al. Where there is blood, there is a way: unusual collateral vessels in superior and inferior vena cava obstruction. Radiographics. 2010;30:67–78. 15. Comtois A, Gorczyca W, Grassino A. Anatomy of diaphragmatic circulation. J Appl Physiol. 1987;62:238–244. 16. Fleig WE, Stange EF, Ditschuneit H. Upper gastrointestinal hemorrhage from downhill esophageal varices. Dig Dis Sci. 1982;27:23–27. 17. The North Italian Endoscopic Club for the Study and Treatment of Esophageal Varices. Prediction of the first variceal hemorrhage in patients with cirrhosis of the liver and esophageal varices. A prospective multicenter study. N Engl J Med. 1988;319:983–989. 18. Agarwal AK, Patel BM, Haddad NJ. Central vein stenosis: a nephrologist's perspective. Semin Dial. 2007;20:53–62. 19. Jemal A, Center MM, DeSantis C, et al. Global patterns of cancer incidence and mortality rates and trends. Cancer Epidemiol Biomarkers Prev. 2010;19:1893–1907.
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Downhill Esophageal Varices: A Prevalent Complication of Superior Vena Cava Obstruction From Benign and Malignant Causes Yoel Siegel, MD,* Erica Schallert, MD,† and Russ Kuker, MD* Objective: Downhill esophageal varices (DEV) usually develop secondary to superior vena cava (SVC) obstruction. Downhill esophageal varices have been less well characterized compared to uphill varices. The aim of the study was to characterize the anatomy and etiology of DEV by contrastenhanced computed tomography. Methods: Patients with SVC obstruction were included in the study. Downhill esophageal varices were defined as discrete esophageal submucosal or mucosal vessels. Ten random computed tomographic scans were assessed as controls. Results: Downhill esophageal varices were seen in 11 of 36 patients. Three types of varices were observed. Between 1 and 6 varices were seen in each patient with a diameter of 1 to 5 mm. Conclusions: Downhill esophageal varices can be seen in 30% of patients with SVC obstruction. They have several patterns and are mostly systemic-to-systemic collaterals. The most common etiology associated with DEV is renal failure. Downhill esophageal varices are of small caliber, this may in part account for less frequent bleeding compared to uphill varices. Key Words: superior vena cava obstruction, downhill esophageal varices, end-stage renal disease, lung cancer (J Comput Assist Tomogr 2015;39: 149–152)
D
ownhill esophageal varices (DEV) are venous collateral pathways that usually develop with superior vena cava (SVC) obstruction. Downhill esophageal varices are distinguished from uphill varices (UEV) which are caused by a different etiology, namely portal hypertension. Downhill varices were first coined in the radiology literature in 1964 by Felson and Lessure1 and diagnosed by barium studies. However, with the advent of crosssectional imaging, computed tomography (CT) has become the main tool for diagnosis and demonstrated these vessels as early as 1984.2 The ability of CT to demonstrate these collateral pathways can be affected by technical factors related to the methods of contrast injection. Some of the most common pathways reported in the radiological literature are the mediastinal, esophageal, and diaphragmatic venous plexuses, azygos-hemiazygosaccessory hemiazygos system, and the lateral thoracic and superficial thoracoabdominal venous plexuses.3–6 Although UEV have received much attention in the medical literature, DEV have been less described and characterized. This is largely because morbidity and mortality related directly to DEV are less common than with UEV. Although hemorrhage From the *Thoracic and Abdominal Imaging Sections, Jackson Memorial Hospital, University of Miami Miller School of Medicine, Miami, FL; and †Department of Pediatric Radiology, Texas Children's Hospital, Baylor College of Medicine, Houston, TX. Received for publication July 25, 2014; accepted October 16, 2014. Reprints: Yoel Siegel, MD, Thoracic and Abdominal Imaging Sections, Jackson Memorial Hospital, University of Miami School of Medicine, JMH WW 279, 1611 NW 12th Ave, Miami, FL 33136 (e‐mail: [email protected]). The authors declare no conflict of interest. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
is more common with UEV, there have been multiple reports in the literature describing esophageal hemorrhage from DEV.7–10 Furthermore, it has been proposed that approximately 8% of patient with DEV tend to have upper gastrointestinal bleeds.11 To date, the prevalence of DEV has not been fully characterized in the literature. Also, the etiology of the SVC obstruction causing DEV has not been fully studied. In the previous century, infection and later malignancy were responsible for most of SVC syndromes; however, with the increasing use of catheters and venous indwelling devices such as pacemakers, the incidence of obstruction secondary to benign causes is rising.12 Because the use of central venous access is very common, it is possible that a concurrent rise in associated complications such as SVC obstruction is also occurring, resulting in an increase in incidence of DEV. The aim of the study was to characterize DEV, their morphology, and the causes of associated SVC obstruction.
MATERIALS AND METHODS The study was approved by the institutional review board. An archive search within our institution's PACS system was performed between August 2008 and February 2014, using key words such as superior vena cava obstruction and superior vena cava occlusion. Patients 18 years and older were included in the study, allowing a uniform technique of IV contrast administration and CT scan technique. The patients included in the study had contrast-enhanced CT scans which demonstrated complete or near-complete SVC obstruction. A set definition of near-complete occlusion is not established as there are no precise guidelines available. Hence, to define near-complete occlusion, an arbitrary threshold of 0.2 cm2 or less as measured by a free hand ROI tool of patent SVC lumen was considered near occlusion. In addition to the patients included in the study, 10 randomly selected CT scans of adults were assessed as a control group. All patients were scanned on one of 3 CT scanner types including a 4-channel MX 8000 (Philips Medical System, Best, the Netherlands), 64-channel Somatom Sensation, and 128-channel Definition DS (Siemens Medical Solutions, Forchheim, Germany). Types of contrast intravenous included Omnipaque 350 or 300 (GE Healthcare Princeton, NJ) and Optiray 320 (Mallinckrodt, St Louis, Mo). The rate of injection varied according to the indication for the scan ranging from 2 to 3.5 mL/s. The location at which the SVC was occluded was divided into the following categories: above the level of the azygos vein, below or at the level of the azygos vein or throughout the entire SVC. Downhill esophageal varices were defined as discrete submucosal esophageal tubular enhancing structures indicating venous vessels and were characterized according to course and diameter. The images assessed on the PACS were in the axial plane with thickness of 1.5 mm and reformatted in sagittal and coronal planes.
RESULTS Thirty-six patients were included in the study; 21 men and 15 women. The age range was 22 to 81 years, the average age
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was 53 years, and the median was 55 years. Twenty-two patients demonstrated complete SVC obstruction, whereas 14 patients demonstrated near-complete SVC obstruction. In 17 of 36 patients, obstruction was directly related to mass effect from tumor burden. Of the non–tumor-related SVC obstructions, 13 patients had end-stage renal disease and 4 had known malignancy without an obstructing mass. In addition, 1 patient had sickle cell disease and 1 coagulopathy leading to chronic obstruction. Downhill esophageal varices were identified in 11 of 36 patients with the following background diseases: end stage renal disease (n = 6), chest mass (n = 3), sickle cell disease (n = 1), and indwelling catheter with history of colon cancer (n = 1). The number of varices identified in each patient was between 1 and 6 vessels. The range of variceal diameters was between 1 and 5 mm; however, most of the patients had varices between 2 and 3 mm. Six patients had larger varices that ranged from 3 to 5 mm (only 1 patient had 5-mm varix diameter). Three distinct patterns of DEV were identified. Pattern 1 represented varices extending from the upper third to the middle third of the esophagus. Pattern 2 included varices extending from the middle third to the lower third of the esophagus. Pattern 3 contained those varices starting in the upper third and continuing into the lower third of the esophagus (Figs. 1–4). Some of the patients demonstrated small, focal, or very short tubular enhancing structures in the mucosa/submucosa of the esophagus that may be small esophageal vessels or mucosal enhancement. However, as this finding was also seen in some of the scans in the control group, it may not represent a pathological finding. None of the control CT scans demonstrated the specific 3 patterns of DEV described above. Of the 3 DEV types identified, the largest diameter of 4 mm was seen in pattern 3. The location of obstruction of the SVC and the associated types of varices can be seen in Tables 1 and 2. Evaluation of the drainage of the varices showed that most of the varices connected to adjacent mediastinal veins as part of a network of vessels. There was no clear direct connection between the varices and the portal system. However, at least 1 patient with DEV had a complex venous plexus in the paraesophageal and left abdominal region that did drain into the portal system. In some of the cases, the drainage below the diaphragm was to the hepatic
FIGURE 1. Schematic drawing of the types of DEV. The esophagus is divided into 3 regions as follows: upper third, middle third, and lower third. Three types of DEV are depicted. Type 1, Extending from the upper third to the middle third of the esophagus Type 2, Extending from the middle third to the lower third of the esophagus Type 3, Starting in the upper third and continuing into the lower third. Figure 1 can be viewed online in color at www.jcat.org.
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FIGURE 2. Type 1, A 56-year-old man with lung cancer and near-complete obstruction of the SVC. Sagittal MPR image of a contrast enhanced CT show DEV extending from the upper third to the middle third of the esophagus (arrows). The DEV appears discontinuous because of its tortuous course.
veins and the inferior vena cava (Fig. 5); whereas in others, the drainage was not clearly identified. A review of the electronic medical charts did not reveal a gastrointestinal hemorrhage directly attributable to the varices in any of the patients.
DISCUSSION In this study, we evaluated DEV in the setting of SVC obstruction. We found that DEV are relatively common in association with SVC obstruction. In this cohort, DEV were
FIGURE 3. Type 2, A 47-year-old woman with end-stage renal disease on hemodialysis with occlusion of the SVC. Coronal maximal intensity projection (MIP) image of a contrast enhanced CT in bone window demonstrates submucosal esophageal varices (arrow), extending from the mid/upper esophagus to the distal esophagus. © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
J Comput Assist Tomogr • Volume 39, Number 2, March/April 2015
Downhill Esophageal Varices
TABLE 2. Location of SVC Obstruction Obstruction Obstruction Obstruction Involving DEV Type Above Azygos Below Azygos Azygos or All SVC 1 2 3
* * *
* * *
Table 2 shows that no association between the type of DEVand the level of obstruction was found. *indicates that this type of varices was associated with obstruction at the above level.
present in 30% of patients with complete or near-complete SVC obstruction. These veins have a range in size measuring up to 5 mm in diameter. We were able to identify 3 patterns or types of DEV anatomy related to their course. The most common being type 3, where the varix begins in the upper third and continues into the lower third of the esophagus. It has been reported that an obstruction below the azygos vein leads to varices involving the upper third of the esophagus, whereas an obstruction involving the azygos vein would have varices throughout the esophagus.1,10 In this study, we did not find a consistent type of varix about the location of SVC obstruction. This may be due to an overall increase in the venous pressure regardless of the origin of obstruction in the SVC and recruitment of all available collateral channels. Also, it is likely that CT is very sensitive to smaller varices that would otherwise not be clearly identified by other modalities such as barium swallow or direct endoscopic visualization. Drainage of collateral vessels from obstruction of the SVC into the portal system has been described, for example, DEV draining into a plexus that communicates with the coronary vein and thus joining the portal system.10,13,14 In most of the CT scans we reviewed, this communication was not apparent. Rather, the
FIGURE 4. Type 3, A 62-year-old man with end-stage renal disease on hemodialysis with occlusion of the entire SVC. Curved MPR image of a contrast enhanced CT demonstrates submucosal esophageal varices (arrow), beginning in the upper third of the esophagus and continuing into the lower third.
TABLE 1. DEV* Type Characterization DEV Type
Number
Non-Mass/Mass Related SVC Obstruction
1 2 3 Total
2 (20%) 3 (30%) 6 (50%) 11
2/0 2/1 5/1 8/2
*Downhill esophageal varices.
FIGURE 5. A 54-year-old woman with end-stage renal disease and type 2 DEV. The esophageal varix depicted is draining into the confluence of the inferior vena cava and inferior phrenic vein (white arrow) indicating a systemic-to-systemic collateral pathway. Note dilated azygos vein (black arrow).
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J Comput Assist Tomogr • Volume 39, Number 2, March/April 2015
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most common patterns were systemic-to-systemic venous collateral pathways. We most commonly observed collateral vessels communicating between the DEV and the hepatic veins or the IVC. Laboratory studies have shown that anastomoses exist between the inferior phrenic vein, which drains into the IVC, and the internal mammary and intercostal veins.15 It is therefore likely that these same pathways were seen in our study, that is, the collateral veins drain directly into the IVC without coursing through the portal system. We did, however, see one systemic to portal venous pathway. These observations suggest that DEV are usually not a reversal of the portosystemic pathway seen in UEV, but rather part of a systemic-to-systemic venous pathway in most cases. Complications caused by DEV are not as common as seen in UEV, the most severe being hemorrhage. In our cohort of patients, there was no chart documentation of gastrointestinal bleeding attributable to the varices; although in the literature, approximately 8% of patients with DEV may have upper gastrointestinal bleeds.11 The reason why UEV are more prone to bleeding than DEV is unclear. It may be related to the coagulopathic state of cirrhotic patients. It has also been postulated that UEV are invariably located at the distal esophagus where they are more vulnerable to erosive gastroesophageal reflux and thus to bleeding.16 Another explanation may be related to the vessel diameters. A study by the northern Italian endoscopic club showed that the diameter of UEV correlates with propensity to bleed in patients with cirrhosis, and in that study, a varix more than 4 mm was considered large.17 In our study, most of the varices were smaller than 4 mm and only 1 patient had a varix of 5 mm. This smaller caliber of vessels may be secondary to lower pressure gradients then seen in UEV that bleed. Of interest is that most of the varices in our study were in patients with end-stage renal disease. Patients on hemodialysis have a high rate of central venous narrowing. The cause of this increased risk for venous narrowing is multifactorial and includes among others endothelial injury, turbulent blood flow, and tendency for thrombosis.18 This may explain the high prevalence of SVC obstruction in patients on hemodialysis. In addition, patients on hemodialysis are usually treated for many years. This extended time frame may allow the varices to develop as opposed to patients with malignant causes, where the onset of SVC occlusion may be shorter. One weakness of this study is that we did not correlate the patient's symptoms with the radiological findings. There may be a correlation of the variceal pattern to certain patient presentations. However, the goal of the study was to describe DEV anatomically and the associated causes of SVC obstruction. Possibly a future study can correlate symptoms with certain types of varices. Of all the variety of collateral vessels that have been described and their pathways that result from SVC obstruction, most do not cause significant morbidity and mortality. We did not encounter any patients with proven gastrointestinal hemorrhage. Nevertheless, DEV have the potential for significant complications and may be underappreciated as a source of gastrointestinal hemorrhage. It is important for radiologists and clinicians to be aware of these varices to include DEV as a potential source of gastrointestinal bleed. Also, it seems that the incidence of longterm SVC obstruction will rise as the use of central venous access and instrumentation becomes more frequent and as the life expectancy of cancer patients increases.19 As the number of procedures and patients with SVC obstruction rise, so it is assumed, will the incidence of DEV. In summary, DEV seem to be a relatively common collateral pathway in patients with SVC obstruction. They demonstrate
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multiple patterns of distribution and usually form systemic-tosystemic collateral bypasses. When compared to UEV, DEV are mostly smaller in caliber than UEV which that are more prone to bleed. Downhill esophageal varices are more commonly present in benign causes of SVC obstruction.
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Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
