PORTAL HYPERTENSION

BY

DR NIKHIL AMEERCHETTYMS (general surgery ) RESIDENT

E – MAIL nikhilameerchetty@gmail.com

ANATOMY• The portal vein arises from the post duodenal plexus of the embryonic

viltelline veins. In the adult the portal vein and its tributaries have no valves• It provides -75% of hepatic blood flow and 50% of the oxygen delivery • 'Ihe portal vein trunk is 4.8 to 8.8 Cm long with an average length of

6.4 cm and o.6 to 1.2 cm wide. with an average width of 0.9 cm.• It is formed behind the neck of the pancreas at the level of the second

lumbar vertebra by the confluence of the superior mesenteric vein (SMV) and the splenic vein

PORTAL HYPERTENSION

• Portal hypertension is defined by a portal pressure higher than 5 mm Hg. However, higher pressures (8 to 10 mm Hg) are typically required to begin stimulating the development of portosystemic collateralization.• If pressure >12 mmHg chances of variceal bleeding• Pressure >15mmHg brisk bleeding • Pressure > 20mmHg continuous bleeding

PATHOPHYSIOLOGY• Block to portal flow leads to increased portal pressure. • Splanchnic vascular bed response. (a)Initial increased vasoconstrictor and decreased vasodilator

response increases intrahepatic resistance. (b)Secondarily, the vasodilator response dominates, with increase

in splanchnic inflow. Collaterals develop between the portal circulation and the systemic circulation.

(c)Plasma volume expansion occurs with the development of a systemic hyperdynamic circulation.

PORTOSYSTEMIC ANASTOMOSIS

• It is important to know the points of communication between the portal and systemic (caval, azygous, and hemiazygous) venous systems

• Most important portosystemic anastomoses are the veins of the proximal stomach and distal esophagus. which receive flow from the coronary and short gastric veins and drain into the superior venacava via the azygous system.

• 'Ihe submucosal venous plexus in the rectum between the superior hemorrhoidal veins (the portal system) and the middle and inferior hemorrhoidal veins (the cavalsystem)

• The paraumbilical veins, connect the left portal vein to the epigastric venous network ‘This plexus can become the variceal "caput Medusae· in patients with portal hypertension and produce the Cruveilhier-Baumgarten syndrome.

• Relzlus veins: a group of small but numerous retroperitoneal veins that connect abdominal viscera. both tubular and solid. with the caval system via intercostals.phrenic, hunbat and renal veins

CAUSES • PRE-HEPATIC • HEPATIC 1) PRESINUSOIDAL 2) SINUSOIDAL 3) POST SINUSOIDAL

• POST HEPATIC

1. Portal vein thrombosis2. Malignant occlusiona) Congenitalb) Sepsisc) Trauma3. Splenic vein thrombosis

Extrahepatic

1. Schistosomiasis2. Congentitalhepatic fibrosis

1.Cirrhosis 1. Budd-Chiari2. Veno-occlusivedisease

Sinusoid Hepaticvein

Pre sinusoidal

PRE HEPATIC1.)Extrahepatic portal hypertension is the most common cause of portal hypertension • ” cavernomatous transformation of the portal vein” Centripetal

distribution of the collaterals .2.)Isolated splenic vein thrombosis (left-sided portal hypertension) is usually secondary to pancreatic inflammation or neoplasm. • gastrosplenic venous hypertension, with superior mesenteric and

portal venous pressures remaining normal. • Importance - Easily reversed by splenectomy alone

INTRAHEPATIC • The most common cause of Intrahepatic presinusoidal hypertension is

schistosomiasis. • Most common cause of portal hypertension at the sinusoidal is “Alcoholic

cirrhosis” 1)Vasodilators produced in the body such as cytokines and TNF alpha stimulate the endothelial vasodilators (NO) and prostacyclins causing splanchnic hypertension2) secondary to deposition of collagen in the space of Disse. • Centrifugal distribution of the collaterals.

EVALUATION

(1) Diagnosis Of The Underlying Liver Disease

(2) Estimation Of Functional Hepatic Reserve

(3) Definition Of Portal Venous Anatomy And Hepatic Hemodynamic Evaluation

(4)Identification Of The Site Of Upper Gastrointestinal Hemorrhage.

ASSESSMENT• Jaundice, Ascites, Encephalopathy, And Malnutrition - End-stage Liver

Disease.• Specific Serologic Markers - Viral Hepatitis,• Antimitochondrial Antibody – Primary Biliary Cirrohosis• Iron Studies - Heamocromatosis • 1-antitrypsin – Cirrhosis Of Liver• Ceruloplasmin Levels – Wilson’s Disease• Alpha-fetoprotein (AFP) should be measured in all such patients as a

screening test for hepatoma.

SCROING SYSTEMS • Child-Turcotte-Pugh score .• Useful to assess the prognosis

• Model for End-stage Liver Disease (MELD) score .• Useful to predict the mortality

Score = 0.957 × loge creatinine (mg/dL) + 0.378 × logebilirubin (mg/dL) + 1.120 loge INR

CHILD-TURCOTTE-PUGH SCORE

• Parameter 1 Point 2 Points 3 Points

• Serum bilirubin (mg/dL) <2 2–3 <3• Albumin (g/dL) >3.5 2.8–3.5 <2.8• Prothrombin time ( S) 1–3 4–6 >6• Ascites None Slight Moderate• Encephalopathy None 1–2 3–4

• Grades: A 5–6 points B 7–9 points C 10–15 points

• Ultrasound to show overall liver morphology to pick up focal lesions suggestive of hepatoma.

• Contrast-enhanced computed tomography (CT) scan or magnetic resonance imaging (MRI) alone or in combination with CT, MRI angiography for morphologic assessment.

• Liver biopsy may be required to confirm cirrhosis, and in focal lesions, to differentiate hepatocellular carcinoma from regenerative nodules.

• Doppler ultrasound can assess the hepatic artery, portal and hepatic veins

• Quantitative liver testing with studies such as • Indocyanine green clearance• Galactose elimination capacity• Monoethylglycinexylidide (MEGX)

ANGIOGRAPHY

• Portal pressure is measured indirectly from the hepatic veins by measuring wedged and free hepatic vein pressures, difference is hepatic venous pressure gradient(HVPG).

• Done using a balloon occlusion technique akin to a Swan-Ganz catheter measurement in the pulmonary circulation.

• Normal HVPG is 6–8 mm Hg, and in cirrhosis it will be greater than 10 mm Hg.

UPPER GI ENDOSCOPY

• All patients with cirrhosis should have an upper endoscopy.

1. 30% patients with cirrhosis develop portal hypertension.2. 30% patients with portal hypertension will bleed from

varices within 2 years.3. The rate of development of varices in patients with

cirrhosis approximately 8% per year.

TREATMENT1. PHARMACOTHERAPY2. VARICEAL TAMPONADE3. ENDOSCOPIC THERAPY4. DECOMPRESSIVE SHUNTS—RADIOLOGIC TIPS SURGICAL TOTAL PARTIAL SELECTIVE

4. DEVASCULARIZATION OPERATIONS5 LIVER TRANSPLANTATION

PHARMACOTHERAPY• Antibiotic Prophylactic Should Be Initiated. • Somatostatin, And Its Longer Acting Analogue Octreotide, Are As Efficacious

As Endoscopic Treatment For Control Of Acute Variceal Bleeding. • Combination Of Octreotide And Endoscopic Therapy Is More Effective In

Controlling Bleeding Than Octreotide Alone And Is The Preferred Treatment For Most Patients.

• In Severe Cases Of Hemorrhage, Vasopressin Can Be Used To Diminish Splanchnic Blood Flow.

• The Target For Treatment Is Less Than 12 Mm Hg Reduction In Hvpg. If This Is Achieved, Patients Will Not Bleed.

• Other Pharmacologic Agents Such As Nitrates, Serotonin Antagonists, And Calcium Channel Blocker, Non selective beta blockers.

VARICEAL TAMPONADE• Sengstaken- Blakemore tube is usedAdvantage : • Immediate cessation of bleeding in more than 85% of patients• widespread availability of this device Disadvantages • Cannot be used in the gastric varices• Recurrent hemorrhage in up to 50% of patients after balloon deflation• Discomfort for the patient• High incidence of serious complications when used incorrectly by an

inexperienced health care provider.

Modified sengstaken-Blakemore tube

ENDOSCOPIC THERAPY

• ENDOSCOPIC BANDING• The current standard for endoscopic therapy for esophageal varices is

endoscopic banding. ADVANTAGES: fewer side effects, obliterates varices faster, and can be easily applied. Multiband ligators allow the firing of six to eight bands in a spiral fashion • A course of banding—usually two to three sessions—is then applied

over the next month to 6 weeks• ENDOSCOPIC SCLEROTHERAPY • Endoscopic sclerotherapy with injection of a sclerosing solution may

be a useful adjunct to complete the obliteration of smaller varices that cannot be banded.

Decompressive Shunts

• Decompression is considered second-line treatment • Reserved for patients who rebleed through pharmacologic

therapy and endoscopic banding or whose varices remain “high risk.”

1. Radiologically placed shunt—TIPS.2. Surgical shunts Total, Partial, and Selective shunts.

TRANSJUGULAR INTRAHEPATIC PORTOSYSTEMIC SHUNT (TIPS)

• Direct puncture of the internal jugular vein (IJV), • passage of a catheter through the right atrium into one of the major hepatic veins

followed by a trans-parenchymal puncture of the liver to cannulate the portal vein.• The catheter is passed into the portal vein • The intraparenchymal track is then dilated and the track stented with an

expandable metal stent in the 10- to 12-mm-diameter range. • The technical success rate is high (>90%) with a low procedural morbidity and

mortality (<10%). • Patients are usually in the hospital for 1–2 days and the shunt patency should be

documented the day after the procedure with a Doppler ultrasound.

TIPS

• It is a temporary procedure • Advantages:• Useful in patients waiting for the transplant • Useful in advanced hepatic functional decompensation

who are unlikely to survive for longer duration• Useful for the treatment of medically intractable ascites.

TIPS• DISADVANTAGES• Shunt stenosis• Shunt thrombosis • Seen within the first year. • Covered TIPS stents have reduced thrombosis and stenosis rates. • Reintervention rates to maintain patency are high with uncovered stents,

ranging from 40 to 80% and 20% with covered stents.• Rebleeding rates for TIPS are around 20%, and this was reduced to 13% in the

covered stent

• Shunt stenosis, which is usually secondary to neointimal hyperplasia, is more common than thrombosis and can often be resolved by balloon dilation of the TIPS or, in some cases, by placement of a second shunt.

Shunts Total Shunts1. End-to-side portacaval shunt2. Side to side portocaval shunt (diameter >10mm) Partial shunts 3. Side to side portocaval shunt(diameter <8mm)

Selective shunts 4. Distal splenorenal shunt

End-to-side portacaval shunt

• In end to side portocaval shunt (Eck fistula) portal vein is divided close to the hilus of the liver and the splanchnic end anastomosed to the side of the vena cava.

• It does not relieve ascites but will control variceal bleeding.

• Complications : portosystemic encephalopathy and accelerated hepatic failure.

Side to side portocaval shunt

• side-to-side portacaval shunts with direct vein-to-vein or a short interposition graft, or the other inter- position shunts such as mesocaval or mesorenal

• These shunts need to be at least 10 mm in diameter, usually being 12–15 mm, to fully decompress portal hypertension.

• shunts differ from the end-to-side portacaval shunt in that the intact upper end of the portal vein serves as a decompressive outflow from the high-pressure–obstructed liver sinusoids.

• Hence, in addition to controlling variceal bleeding, these shunts also control ascites.

Splenorenal shunt

• The conventional splenorenal shunt consists of anastomosis of the proximal splenic vein to the renal vein.

• Splenectomy is performed.• Complications : shunt thrombosis

• The only indication for a total portal systemic shunt at present is for patients with acute Budd-Chiari syndrome

Partial Shunts

• Partial shunts are side-to-side shunts whose diameter is reduced to 8 mm.

• 90% control of variceal bleeding • polytetrafluoroethylene (PTFE) graft is approximately 2–3

cm long, and beveled at each end to give a larger anastomosis.

Selective Shunts

• Selective shunts are most commonly the distal splenorenal shunt (DSRS)

• Divide the splenic vein at its junction with the superior mesenteric vein, and anastomoses the splenic vein to the left renal vein.

• This selectively decompresses gastroesophageal varices. • Control of bleeding has been at 94%, with good portal perfusion

maintained in 90% of patients initially. • The overall incidence of encephalopathy has been around 15%

following this operation.

Devascularization Procedures

• Sugiura operation• These operations approach the problem of variceal bleeding by interrupting inflow to the

varices. • The components are splenectomy, gastric and esophageal devascularization, and possibly

esophageal transaction • The effectiveness of these procedures appears to depend on the aggressiveness of the

operation. • The advantage of these procedures is that portal hypertension is maintained with portal flow to

the cirrhotic liver. • Devascularization can be useful when patients have extensive portal and splenic venous

thrombosis and there are no other operative or radiologic options.

Meso-Rex bypass

• Direct portal revascularization can be achieved by interposing a vascular graft between the SMV and the Rex recessus (left portal vein system)

• MRB achieves a very successful physiologic cure of chronic portal hypertension and restores the portal flow into and through the liver graft.

• Primary revascularization of liver grafts• Managing early acute portal vein thrombosis episodes.

Liver transplant

• Liver transplant is the most commonly used operation for patients with portal hypertension at the present time.

• The major issues are1. Patient Selection2. Timing Of Transplant, 3. Expanding The Donor Pool 4. Outcomes.

Patient selection• Standards for patient listing have been set by the United Network for

Organ Sharing (UNOS)• The indication for transplant is end-stage liver disease• Variceal bleeding ,ascites and encephalopathy are clinical indicators

of end-stage liver disease.• comorbid medical conditions and a psychosocial suitability for

transplant particularly in the alcoholic and other chemical dependency patient populations.

• Hepatitis C population with hepatoma

Timing

• The timing of transplant is dictated by the severity of the underlying liver disease.

• Prioritization for organs occurs on the basis of MELD scores

• Sickest patients receiving cadaveric organs first based on bilirubin, prothrombin time, and serum creatinine.

• Timing is dictated by these objective criteria rather than individual physician decisions in day-to- day patient management

outcomes

Hospital mortality remains at less than 10%, 80+% 1-year survival 60–65% 5-year survival

THE MULTIDISCIPLINARY TEAM

Hepatologists are in the front line for diagnosing and directing the management for many of the clinical presentations. Endoscopists play an important role diagnostically and in primary therapy for managing variceal bleeding. Endoscopic banding requires significant expertise. Radiologists, both imaging and interventional, play roles in diagnosis, directed biopsy, and procedural (TIPS) manage- ment of these patients. Surgeons play a major role in liver transplant but may also have a role in shunting good-risk patients with refractory variceal bleeding.

• Pathologists with an interest in liver pathology are important in the accurate diagnosis and staging of disease severity.

• Critical care physicians and anesthesiologists are vital team members when patients with portal hypertension have acute events and in their perioperative management.

• Nephrologists, cardiologists, and pulmonologists all play a role in the management

Finally, who coordinates? In a complex multidisciplinary team

• coordinators are the ones to whom the patients turn for help in navigating their way through management in this complex field

• Thank you