Clinical Significance of Umbilicoportal Manometry Yvan J. Silva, MD, FRCS(C), FACS,’ Detroit, Michigan Janaki Varadhan, MD,+ Detroit, Michigan Sidlaghatta A. Ramesh, MD,* Detroit, Michigan
Determination of portal pressure is significant in the assessment of patients with hepatobiliary disease in whom esophageal variceal bleeding has been documented or is suspected. At definitive portal decompression, the surgical procedure and the estimation of the success of decompression rely on determinations of portal and systemic venous pressures and the gradient between them. These measurements are made with the patient under anesthesia, at laparotomy, with attendant dissipation of intraabdominal pressure, and do not reflect the dynamic state of the portal circulation as occurs in the intact unanesthetized state. All methods used for measurement of portal pressure are invasive and subject the patient to various degrees of risk. They are furthermore heterogenous in that portal pressures differ in the anesthetized and dynamic states. In a review of available data Sedgwick and Poulantzas [I] concluded that the upper limits of normal portal pressure with the following methods were: portal pressure at laparotomy, 17 cm of saline; percutaneous splenic puncture, 23 cm of saline; and wedged hepatic venous pressure, 9.5 cm of saline. Several reports have discussed the technique and scope of umbilical vein catheterization for portal manometry [2-61 and splanchnoportography [ 710]. We have used umbilical vein catheterization for manometry [6], studies of the effects of systemically administered vasopressin on the portal circulation [I I], and portal decompression [12] and have shown that Valsalva maneuvers increase portal pressures by 55 to 64 cm of saline in intact unanesthetized patients [II]. Utilizing indwelling umbilical vein catheters, we From the Department of Swgery, Wayne State University School of Medicine. Detroit, Michigan. This work was supported by the Detroit General Hospital Research Corooration and Grant no. 206-1502. Wavne State Universitv. Reprint re&ests should be addressed to Yvan J. &Iv=, MD, Department of Surgery, Harper Hospital, 3990 John R., Detroit, Michigan 48201.
Volume 138, August 1979
performed this study to establish values for normal pressures in the intact unanesthetized state, observe diurnal variations, and measure changes in portal pressure brought about by anesthesia and dissipation of intraabdominal pressure during laparotomy. Material and Methods Ninety-six adult patients had umbilical vein catheters inserted and left indwelling for 1 to 5 days. There were 60 men and 36 women. Ages ranged from 17 to 81 years (mean 38.6). Indications for catheterization were upper gastrointestinal bleeding of undetermined cause, suspected or documented esophageal variceal bleeding, or suspected liver disease. Informed consent was given by all patients after description of the procedure and methods of care of indwelling catheters. Seventy-five patients had the procedure performed under local anesthesia: the remainder preferred or required general anesthesia. At operation wedge liver biopsy specimens were obtained under direct vision. Portal pressures were measured with the patient in the recumbent position using the midaxillary line as the 0 reference point, and the mean between two levels of respiratory fluctuation was taken to be the pressure. Pressures were recorded in the fasting state, in the midmorning, and postprandially in the afternoon and in the evening. They were also recorded while the patients performed a Valsalva maneuver. Ten patients who had extraperitoneal catheterization required laparotomy 1.5 days to 7 months after the initial procedure. The umbilical vein was recatheterized and portal manometry was carried out during operation. There were eight men and two women aged 42 to 64 years (mean 50). Six patients were documented to have a cirrhotic liver and four had a normal liver at the initial operation. Twenty additional patients undergoing routine cholecystectomy consented to have umbilical catheterization. There were 19 women and 1 man. After induction of anesthesia, extraperitoneal umbilical vein catheterization was performed. Portal pressures were measured during the procedure, before and after laparotomy and aft,er abdominal closure. Catheters were left indwelling 1 to 3 days after the operation and portal pressures measured four times a day.
305
Silva et al
Technique
We followed a technique previously reported [6] with attention to the hazards and prevention of complications. A 3 inch vertical midline abdominal incision was made in the middle third between the xiphoid and the umbilicus. The linea alba was incised and the umbilical vein identified in the preperitoneal fat. It was hemitransected and dilated with Bakes’ dilators successively from 3 to 7 mm through the umbilicoportal junction, and a no. 14F polyethylene catheter was inserted into the left portal vein lumen. A brisk outflow of portal blood signified proper placement and the catheter was tied into the vein with no. 2/O silk ligatures. The proximal end of the catheter was brought out through a stab wound in the upper abdominal wall and the incision closed. Difficulties in identification of the vein were approached by opening the peritoneum, incising the falciform ligament, and identifying and catheterizing the vein but bringing the catheter out extraperitoneally. Wedge liver biopsy specimens were obtained in all patients under direct vision. Indwelling catheters were secured with adhesive tape and the exit sites cleaned daily and treated wit4 antibiotic ointment. Slow infusion (50 ml/hour) of Ringer’s lactate solution (1,000 units of heparin/liter) was carried out through the catheters. Removal of catheters was accomplished by stopping the infusion, pulling the
90
a
j 1
0
catheter 3 to 5 cm, clamping the catheter, and incorporating it into the dressing. Twenty-four hours later on unclamping the catheter, if no efflux of blood occurred, it was removed. Results
In the first group of 96 patients, 50 patients had normal livers histologically whereas 46 had the following pathologic conditions: 42 had cirrhosis, 1 had schistosomal hepatic fibrosis, 2 had massive liver metastases, and 1 had congenital polycystic disease. The mean value for portal pressure in normal patients was 16.08 f 2.87 (mean f standard error of difference [SED]) cm of saline. The lowest value in the abnormal group was seen in a patient with metastatic liver disease (Figure 1). Variations in portal pressure during postural changes, postprandially and diurnally, were minimal and not statistically significant. Umbilical vein catheterization by the extraperitoneal approach was unsuccessful in five patients with normal livers and eight patients with cirrhosis. Opening the peritoneum led to successful catheterization by direct manipulation in all five normal patients and in five with cirrhosis. Three cirrhotic patients could not be catheterized and are not included. Minor wound infections developed in three patients and one was later noted to have an incisional hernia. In the 10 patients in whom umbilicoportal manometry was repeated 1.5 fo 210 days later, during laparotomy, all but one showed a decrease in portal pressure (Figure 2). The decrease in portal pressure was variable and not statistically significant.
J Normal 50 Patients
&anesthetized 46 Patients
Figure 1. Portal pressures measured in 50 patients with normal livers and 46 patients with liver disease. 306
I
I Interval in Days
Anesthetized
Figure 2. Portal pressures measured initially vta extraperitoneat umbilical catheters and repeated at laparotomy. The American Journal of Surgery
Umbilicoportal
In the 20 patients undergoing cholecystectomy, it was found that with the patients under anesthesia the portal pressure was 2.7 f 1.3 (SED) cm of saline (average) lower when the abdominal cavity was opened compared to the pressure obtained during extraperitoneal umbilical vein catheterization. The average portal pressure was 2.5 f 1.7 (SED) cm of saline greater after recovery from anesthesia over 1 to 3 postoperative days when compared to measurements obtained during extraperitoneal catheterization under anesthesia. These variations were not statistically significant. Comments
Umbilicoportal catheterization is a simple, reliable procedure that can provide continuing access to the portal circulation in the intact unanesthetized state. Feasibility is limited by several factors, including experience of the surgeon with the technique, size of the umbilical vein, and the presence of liver disease. White et al [IO] were able to catheterize the umbilical vein and obtain portograms in 22 of 30 patients. Braastad et al [3] reported on 30 patients without and 1 with portal hypertension, catheterization being successful in 29. Feasibility is further restricted when the umbilicoportal area is effaced by bosselations of cirrhotic tissue or metastatic carcinoma. In our experience the most common reason for inability to catheterize the vein is failure to identify the original lumen, leading to creation of false passages during dilatation. These false passages are of little consequence, should be suspected if dilatation of the umbilicoportal junction is difficult, and can be recognized by visualizing the tip of the metal dilator by opening the peritoneum. Backbleeding from the left portal vein into the peritoneal cavity has been reported [6] and is best prevented by observing the original lumen for the presence of blood during venotomy and avoiding the creation of false passages. Failure of catheterization in this instance is best approached by ligation of the vein above the venotomy site. Repeated catheterization is possible, 10 patients in this series having had the procedure repeated 1.5 days to 7 months later. There is no report of mortality resulting from umbilical vein catheterization. One significant hazard is exsanguination, which can occur from improper fixation of the catheter at operation, leading to avulsion from the wound and backbleeding through the venotomy. Subcapsular and intraperitoneal leakage of contrast material during portography has been reported [IO] and may cause ileus. Portal vein thrombosis resulting from indwelling catheters is a potential hazard and is related to length Volume 139, August 1979
Manometry
of time. Silva and Walt [12] reported this complication in two patients 8 and 23 days, respectively, after having undergone extracorporeal umbilicosystemic shunting. Wound infections, hematoma, and incisional hernia can occur. In this series incisional hernia was seen in one patient although the catheter was brought out through a counterincision, allowing for complete closure of the linea alba; this technique was previously suggested [6] to prevent occurrence. Portal pressure varies in the dynamic state and increases transiently during coughing or straining, and with Valsalva and Muller maneuvers and other activities. Krook [13] measured occluded hepatic venous pressures in seven patients and found increases of 20 to 102 mm Hg during Valsalva maneuvers whereas right atria1 pressures increased 31 to 38 mm Hg. Silva et al [II] previously studied 10 patients in whom Valsalva maneuvers were shown to increase portal pressures by 55 to 64 cm of saline measured via umbilicoportal catheters. In this study we observed diurnal changes in portal pressures as well as postprandial changes and found no significant differences. Furthermore, changes during Valsalva maneuvers were similar in patients with and those without portal hypertension. It appears that muscular effort is the single force that causes increase in pressure. The anesthetized state was responsible for decreasing portal pressure by 2.5 f 1.7 (SED) cm of saline in the 20 patients described in this study as well as the 10 patients who were recatheterized 1.5 days to 7 months later. Dissipation of intraabdominal pressure by laparotomy was found to decrease portal pressure by 2.7 f 1.3 (SED) cm of saline in patients reported in this study. The surgeon should consider this information when determining portal pressure at laparotomy. We conclude from measurements in 96 patients that the upper limit of portal pressure in normal human subjects is 22 cm of saline. Since umbilicoportal catheterization affords continuing access to the portal circulation in the basal physiologic state, it is thought that this method recommends itself further for its simplicity and accuracy. Summary
Ninety-six adult patients had measurements of portal pressure over 1 to 5 days via indwelling extraperitoneal umbilicoportal catheters. Liver biopsy specimens obtained during catheterization showed 50 patients to have a normal liver; the remainder had liver disease. Portal pressure averaged 16.08 f 2.87 (SED) cm of saline in normal patients. Ten patients, 307
Silva et al
6 with cirrhotic and 4 with normal livers, were recatheterized 1.5 days to 7 months later when they came to laparotomy. In all but one, portal pressures were decreased during anesthesia and laparotomy. Twenty additional patients undergoing cholecystectomy had portal pressures measured before and after laparotomy, and after recovery from anesthesia for 1 to 3 postoperative days. Laparotomy caused a decrease in portal pressure of 2.7 f 1.3 (SED) cm of saline; after recovery from anesthesia portal pressure was higher by 2.5 f 1.7 (SED) cm of saline. Umbilicoportal catheterization is a safe and accurate t.echnique for studying the portal system. In the intact unanesthetized state, we consider 22 cm of saline to be the upper limit of normal for portal pressure. References 1. Sedgwick CE, Poulantzas JK: Portal Hypertension, p 62. Boston, Little Brown, 1967. 2. Bayly JH, Gonzalez-Carbalhaes 0: The umbilical vein in the adult: diagnosis, treatment and research. Am Surg 30: 56,
308
1964. 3. Braastad FW, Wukasch DD, Jordan PH: The practicality of umbilical vein cannulation in patients with and without portal hypertension. Arch Surg 101: 32, 1970. 4. Lavoie P, Viallet A: Une voie nouvelle d’acces a la veine Porte: la veine ombilicale. Can J Surg 8: 428, 1965. 5. Malt RA, Cony RJ, Chavez-Peon F: Umbilical vein cannulation in portal-system disease. N Engl J Med 279: 930, 1968. 6. Silva YJ: Hazards in umbilical vein catheterization in the cirrhotic patient. Surg Gynecul Obstet 131: 532, 1970. 7. Gonzalez-Carbalhaes 0: Portography: a preliminary report of a new technique via the umbilical vein. C/in Proc Childrens /-/asp (Washington, DC) 15: 120, 1959. 8. Kessler RE, Zimmon DS: Umbilical vein angiography. Radio/ogy 87: 841. 1966. 9. Piccone VA, LeVeen HH, White JJ, Skinner GB, MacLean LD: Transumbilical portal hepatography, a significant adjunct in the investigation of liver disease. Surgery 61: 333, 1967. 10. White JJ, Skinner GB, MacLean LD: Hepatoportography via the umbilical vein: a superior approach to diagnosis in liver disease. Can Med Assoc J 95: 997, 1966. 11. Silva YJ, Moffat RC, Walt AJ: Vasopressin effect on portal and systemic hemodynamics: studies in intact, unanesthetized humans. JAMA 210: 1065, 1969. 12. Silva YJ, Walt AJ: Emergency transumbilical portal decompression for bleeding esophageal varices. Can J Surg 14: 66, 1971. 13. Krook H: Circulatory studies in liver cirrhosis. Acta Med Stand 156 (suppl 318): 1, 1956.
The American Journal of Surgery
Determination of portal pressure is significant in the assessment of patients with hepatobiliary disease in whom esophageal variceal bleeding has been documented or is suspected. At definitive portal decompression, the surgical procedure and the estimation of the success of decompression rely on determinations of portal and systemic venous pressures and the gradient between them. These measurements are made with the patient under anesthesia, at laparotomy, with attendant dissipation of intraabdominal pressure, and do not reflect the dynamic state of the portal circulation as occurs in the intact unanesthetized state. All methods used for measurement of portal pressure are invasive and subject the patient to various degrees of risk. They are furthermore heterogenous in that portal pressures differ in the anesthetized and dynamic states. In a review of available data Sedgwick and Poulantzas [I] concluded that the upper limits of normal portal pressure with the following methods were: portal pressure at laparotomy, 17 cm of saline; percutaneous splenic puncture, 23 cm of saline; and wedged hepatic venous pressure, 9.5 cm of saline. Several reports have discussed the technique and scope of umbilical vein catheterization for portal manometry [2-61 and splanchnoportography [ 710]. We have used umbilical vein catheterization for manometry [6], studies of the effects of systemically administered vasopressin on the portal circulation [I I], and portal decompression [12] and have shown that Valsalva maneuvers increase portal pressures by 55 to 64 cm of saline in intact unanesthetized patients [II]. Utilizing indwelling umbilical vein catheters, we From the Department of Swgery, Wayne State University School of Medicine. Detroit, Michigan. This work was supported by the Detroit General Hospital Research Corooration and Grant no. 206-1502. Wavne State Universitv. Reprint re&ests should be addressed to Yvan J. &Iv=, MD, Department of Surgery, Harper Hospital, 3990 John R., Detroit, Michigan 48201.
Volume 138, August 1979
performed this study to establish values for normal pressures in the intact unanesthetized state, observe diurnal variations, and measure changes in portal pressure brought about by anesthesia and dissipation of intraabdominal pressure during laparotomy. Material and Methods Ninety-six adult patients had umbilical vein catheters inserted and left indwelling for 1 to 5 days. There were 60 men and 36 women. Ages ranged from 17 to 81 years (mean 38.6). Indications for catheterization were upper gastrointestinal bleeding of undetermined cause, suspected or documented esophageal variceal bleeding, or suspected liver disease. Informed consent was given by all patients after description of the procedure and methods of care of indwelling catheters. Seventy-five patients had the procedure performed under local anesthesia: the remainder preferred or required general anesthesia. At operation wedge liver biopsy specimens were obtained under direct vision. Portal pressures were measured with the patient in the recumbent position using the midaxillary line as the 0 reference point, and the mean between two levels of respiratory fluctuation was taken to be the pressure. Pressures were recorded in the fasting state, in the midmorning, and postprandially in the afternoon and in the evening. They were also recorded while the patients performed a Valsalva maneuver. Ten patients who had extraperitoneal catheterization required laparotomy 1.5 days to 7 months after the initial procedure. The umbilical vein was recatheterized and portal manometry was carried out during operation. There were eight men and two women aged 42 to 64 years (mean 50). Six patients were documented to have a cirrhotic liver and four had a normal liver at the initial operation. Twenty additional patients undergoing routine cholecystectomy consented to have umbilical catheterization. There were 19 women and 1 man. After induction of anesthesia, extraperitoneal umbilical vein catheterization was performed. Portal pressures were measured during the procedure, before and after laparotomy and aft,er abdominal closure. Catheters were left indwelling 1 to 3 days after the operation and portal pressures measured four times a day.
305
Silva et al
Technique
We followed a technique previously reported [6] with attention to the hazards and prevention of complications. A 3 inch vertical midline abdominal incision was made in the middle third between the xiphoid and the umbilicus. The linea alba was incised and the umbilical vein identified in the preperitoneal fat. It was hemitransected and dilated with Bakes’ dilators successively from 3 to 7 mm through the umbilicoportal junction, and a no. 14F polyethylene catheter was inserted into the left portal vein lumen. A brisk outflow of portal blood signified proper placement and the catheter was tied into the vein with no. 2/O silk ligatures. The proximal end of the catheter was brought out through a stab wound in the upper abdominal wall and the incision closed. Difficulties in identification of the vein were approached by opening the peritoneum, incising the falciform ligament, and identifying and catheterizing the vein but bringing the catheter out extraperitoneally. Wedge liver biopsy specimens were obtained in all patients under direct vision. Indwelling catheters were secured with adhesive tape and the exit sites cleaned daily and treated wit4 antibiotic ointment. Slow infusion (50 ml/hour) of Ringer’s lactate solution (1,000 units of heparin/liter) was carried out through the catheters. Removal of catheters was accomplished by stopping the infusion, pulling the
90
a
j 1
0
catheter 3 to 5 cm, clamping the catheter, and incorporating it into the dressing. Twenty-four hours later on unclamping the catheter, if no efflux of blood occurred, it was removed. Results
In the first group of 96 patients, 50 patients had normal livers histologically whereas 46 had the following pathologic conditions: 42 had cirrhosis, 1 had schistosomal hepatic fibrosis, 2 had massive liver metastases, and 1 had congenital polycystic disease. The mean value for portal pressure in normal patients was 16.08 f 2.87 (mean f standard error of difference [SED]) cm of saline. The lowest value in the abnormal group was seen in a patient with metastatic liver disease (Figure 1). Variations in portal pressure during postural changes, postprandially and diurnally, were minimal and not statistically significant. Umbilical vein catheterization by the extraperitoneal approach was unsuccessful in five patients with normal livers and eight patients with cirrhosis. Opening the peritoneum led to successful catheterization by direct manipulation in all five normal patients and in five with cirrhosis. Three cirrhotic patients could not be catheterized and are not included. Minor wound infections developed in three patients and one was later noted to have an incisional hernia. In the 10 patients in whom umbilicoportal manometry was repeated 1.5 fo 210 days later, during laparotomy, all but one showed a decrease in portal pressure (Figure 2). The decrease in portal pressure was variable and not statistically significant.
J Normal 50 Patients
&anesthetized 46 Patients
Figure 1. Portal pressures measured in 50 patients with normal livers and 46 patients with liver disease. 306
I
I Interval in Days
Anesthetized
Figure 2. Portal pressures measured initially vta extraperitoneat umbilical catheters and repeated at laparotomy. The American Journal of Surgery
Umbilicoportal
In the 20 patients undergoing cholecystectomy, it was found that with the patients under anesthesia the portal pressure was 2.7 f 1.3 (SED) cm of saline (average) lower when the abdominal cavity was opened compared to the pressure obtained during extraperitoneal umbilical vein catheterization. The average portal pressure was 2.5 f 1.7 (SED) cm of saline greater after recovery from anesthesia over 1 to 3 postoperative days when compared to measurements obtained during extraperitoneal catheterization under anesthesia. These variations were not statistically significant. Comments
Umbilicoportal catheterization is a simple, reliable procedure that can provide continuing access to the portal circulation in the intact unanesthetized state. Feasibility is limited by several factors, including experience of the surgeon with the technique, size of the umbilical vein, and the presence of liver disease. White et al [IO] were able to catheterize the umbilical vein and obtain portograms in 22 of 30 patients. Braastad et al [3] reported on 30 patients without and 1 with portal hypertension, catheterization being successful in 29. Feasibility is further restricted when the umbilicoportal area is effaced by bosselations of cirrhotic tissue or metastatic carcinoma. In our experience the most common reason for inability to catheterize the vein is failure to identify the original lumen, leading to creation of false passages during dilatation. These false passages are of little consequence, should be suspected if dilatation of the umbilicoportal junction is difficult, and can be recognized by visualizing the tip of the metal dilator by opening the peritoneum. Backbleeding from the left portal vein into the peritoneal cavity has been reported [6] and is best prevented by observing the original lumen for the presence of blood during venotomy and avoiding the creation of false passages. Failure of catheterization in this instance is best approached by ligation of the vein above the venotomy site. Repeated catheterization is possible, 10 patients in this series having had the procedure repeated 1.5 days to 7 months later. There is no report of mortality resulting from umbilical vein catheterization. One significant hazard is exsanguination, which can occur from improper fixation of the catheter at operation, leading to avulsion from the wound and backbleeding through the venotomy. Subcapsular and intraperitoneal leakage of contrast material during portography has been reported [IO] and may cause ileus. Portal vein thrombosis resulting from indwelling catheters is a potential hazard and is related to length Volume 139, August 1979
Manometry
of time. Silva and Walt [12] reported this complication in two patients 8 and 23 days, respectively, after having undergone extracorporeal umbilicosystemic shunting. Wound infections, hematoma, and incisional hernia can occur. In this series incisional hernia was seen in one patient although the catheter was brought out through a counterincision, allowing for complete closure of the linea alba; this technique was previously suggested [6] to prevent occurrence. Portal pressure varies in the dynamic state and increases transiently during coughing or straining, and with Valsalva and Muller maneuvers and other activities. Krook [13] measured occluded hepatic venous pressures in seven patients and found increases of 20 to 102 mm Hg during Valsalva maneuvers whereas right atria1 pressures increased 31 to 38 mm Hg. Silva et al [II] previously studied 10 patients in whom Valsalva maneuvers were shown to increase portal pressures by 55 to 64 cm of saline measured via umbilicoportal catheters. In this study we observed diurnal changes in portal pressures as well as postprandial changes and found no significant differences. Furthermore, changes during Valsalva maneuvers were similar in patients with and those without portal hypertension. It appears that muscular effort is the single force that causes increase in pressure. The anesthetized state was responsible for decreasing portal pressure by 2.5 f 1.7 (SED) cm of saline in the 20 patients described in this study as well as the 10 patients who were recatheterized 1.5 days to 7 months later. Dissipation of intraabdominal pressure by laparotomy was found to decrease portal pressure by 2.7 f 1.3 (SED) cm of saline in patients reported in this study. The surgeon should consider this information when determining portal pressure at laparotomy. We conclude from measurements in 96 patients that the upper limit of portal pressure in normal human subjects is 22 cm of saline. Since umbilicoportal catheterization affords continuing access to the portal circulation in the basal physiologic state, it is thought that this method recommends itself further for its simplicity and accuracy. Summary
Ninety-six adult patients had measurements of portal pressure over 1 to 5 days via indwelling extraperitoneal umbilicoportal catheters. Liver biopsy specimens obtained during catheterization showed 50 patients to have a normal liver; the remainder had liver disease. Portal pressure averaged 16.08 f 2.87 (SED) cm of saline in normal patients. Ten patients, 307
Silva et al
6 with cirrhotic and 4 with normal livers, were recatheterized 1.5 days to 7 months later when they came to laparotomy. In all but one, portal pressures were decreased during anesthesia and laparotomy. Twenty additional patients undergoing cholecystectomy had portal pressures measured before and after laparotomy, and after recovery from anesthesia for 1 to 3 postoperative days. Laparotomy caused a decrease in portal pressure of 2.7 f 1.3 (SED) cm of saline; after recovery from anesthesia portal pressure was higher by 2.5 f 1.7 (SED) cm of saline. Umbilicoportal catheterization is a safe and accurate t.echnique for studying the portal system. In the intact unanesthetized state, we consider 22 cm of saline to be the upper limit of normal for portal pressure. References 1. Sedgwick CE, Poulantzas JK: Portal Hypertension, p 62. Boston, Little Brown, 1967. 2. Bayly JH, Gonzalez-Carbalhaes 0: The umbilical vein in the adult: diagnosis, treatment and research. Am Surg 30: 56,
308
1964. 3. Braastad FW, Wukasch DD, Jordan PH: The practicality of umbilical vein cannulation in patients with and without portal hypertension. Arch Surg 101: 32, 1970. 4. Lavoie P, Viallet A: Une voie nouvelle d’acces a la veine Porte: la veine ombilicale. Can J Surg 8: 428, 1965. 5. Malt RA, Cony RJ, Chavez-Peon F: Umbilical vein cannulation in portal-system disease. N Engl J Med 279: 930, 1968. 6. Silva YJ: Hazards in umbilical vein catheterization in the cirrhotic patient. Surg Gynecul Obstet 131: 532, 1970. 7. Gonzalez-Carbalhaes 0: Portography: a preliminary report of a new technique via the umbilical vein. C/in Proc Childrens /-/asp (Washington, DC) 15: 120, 1959. 8. Kessler RE, Zimmon DS: Umbilical vein angiography. Radio/ogy 87: 841. 1966. 9. Piccone VA, LeVeen HH, White JJ, Skinner GB, MacLean LD: Transumbilical portal hepatography, a significant adjunct in the investigation of liver disease. Surgery 61: 333, 1967. 10. White JJ, Skinner GB, MacLean LD: Hepatoportography via the umbilical vein: a superior approach to diagnosis in liver disease. Can Med Assoc J 95: 997, 1966. 11. Silva YJ, Moffat RC, Walt AJ: Vasopressin effect on portal and systemic hemodynamics: studies in intact, unanesthetized humans. JAMA 210: 1065, 1969. 12. Silva YJ, Walt AJ: Emergency transumbilical portal decompression for bleeding esophageal varices. Can J Surg 14: 66, 1971. 13. Krook H: Circulatory studies in liver cirrhosis. Acta Med Stand 156 (suppl 318): 1, 1956.
The American Journal of Surgery
