Abstract
Objective
To investigate the special pattern and possible formation mechanism of extrahepatic arterial blood supply in hepatocellular carcinoma, aiming to improve the effectiveness of interventional treatment.
Methods
516 cases of hepatocellular carcinoma were selected for routine abdominal artery and superior mesenteric artery angiography before interventional embolization, and 121 cases with cancer foci near the diaphragm were added with selective subphrenic, right adrenal, right intercostal or bilateral internal mammary artery angiography to analyze the characteristics of extrahepatic arterial blood supply in hepatocellular carcinoma.
The extrahepatic arterial blood supply was derived from the subphrenic and right adrenal arteries in 68 cases (34.7%), the gastroduodenal and omental arteries in 51 cases (26.0%), the left gastric artery in 42 cases (21.4%), the pancreaticoduodenal artery arch in 24 cases (12.2%), the right colonic artery in 2 cases (1.0%), the internal mammary artery in 5 cases (2.6%), the intercostal artery in 3 cases (1.5%), and the dorsal pancreatic artery in 1 case (1.5%). The extrahepatic collateral circulation was caused by occlusion of the hepatic artery after embolization or surgical hepatic artery ligation in 58 cases (29.6% ), and the rest were primary extrahepatic artery supply. The extrahepatic arterial blood supply was closely related to the primary site and size of the cancer foci. Statistics showed that the right subdiaphragmatic or adrenal artery mainly fed segment VII , VIII hepatocellular carcinomas, the gastroduodenal and omental arteries mainly fed segment IV, V, VI carcinomas, and the left subdiaphragmatic or left gastric artery mainly fed segment II ,III, IV hepatocellular carcinomas, etc. The success rate of cannulation of extrahepatic supply branches was 92.7% (182 cases).
Conclusion
Familiarity with the characteristics of extrahepatic arterial blood supply of hepatocellular carcinoma and mastering its rules are of great significance for accurate and complete blockage of multiple arterial blood supply of hepatocellular carcinoma in clinical practice and improving the survival rate of patients with hepatocellular carcinoma in interventional treatment.
Keywords
Lateral hepatic branch blood supply, hepatocellular carcinoma, embolization, treatment strategy
Hepatic artery embolization (HAE) is currently recognized as the first choice of treatment for patients with inoperable primary hepatocellular carcinoma. However, in clinical treatment, hepatocellular carcinoma often has abnormal extrahepatic blood supply in addition to normal and variant hepatic artery blood supply, which often leads to incomplete tumor embolization treatment during interventional treatment and makes it difficult to receive better efficacy. Therefore, recognizing and exploring the extrahepatic blood supply of hepatocellular carcinoma can undoubtedly help guide the treatment. In this paper, we studied 196 cases of primary hepatocellular carcinoma with extrahepatic blood supply found in our hospital in the past 17 years, aiming to investigate the special rules and possible formation mechanisms of extrahepatic arterial blood supply in hepatocellular carcinoma, in the hope of further improving the effectiveness of its interventional treatment.
1. Materials and methods
1.1 Clinical data The results of digital subtraction angiography (DSA) of HAE in 516 patients with hepatocellular carcinoma with complete clinical data and clear imaging images from January 1992 to January 2009 were retrospectively analyzed. Among them, 455 cases were male and 61 cases were female, aged 24-86 years. All were diagnosed with primary hepatocellular carcinoma by clinical laboratory examination, imaging examination and/or pathological examination.
1.2 Imaging methods All 516 patients with hepatocellular carcinoma were examined by DSA under local anesthesia using the Seldinger technique with percutaneous femoral artery puncture and cannulation. For each case, abdominal trunk imaging and superior mesenteric artery (SMA) imaging were routinely performed. In 121 cases, selective subdiaphragmatic, right adrenal, right intercostal or bilateral internal mammary artery angiograms were performed to fully evaluate the blood supply to the tumor. The machine used was a special angiography machine from Siemens, Germany.
1.3 Analysis method Three interventional radiologists specialized in attending physicians or above observed the enrolled cases to determine whether there were variant hepatic arteries and non-hepatic arterial blood supply of hepatocellular carcinoma. By analyzing the characteristics of extrahepatic arterial blood supply in hepatocellular carcinoma, the relevant information was recorded and summarized separately, and the incidence was counted.
2. Results
2.1 Incidence of extrahepatic arterial blood supply In 516 patients with hepatocellular carcinoma, 196 cases had extrahepatic arterial blood supply, accounting for 38.0%.
2.2 Composition ratio of extrahepatic arterial blood supply Among 196 patients with extrahepatic arterial blood supply, 68 patients (34.7%) originated from the subphrenic and right adrenal arteries, 51 patients (26.0%) from the gastroduodenal and omental arteries, 42 patients (21.4%) from the left gastric artery, 23 patients (11.7%) from the pancreaticoduodenal artery arch, 2 patients (1.0%) from the right colonic artery, 5 patients (2.6%) from the internal mammary artery, and 5 patients ( 2.6%), intercostal artery supply in 3 cases (1.5%) and dorsal pancreatic artery and SMA to tethered anastomotic arterial network supply in 1 case each (0.5%). Figure 4 shows the composition ratio of extrahepatic arterial blood supply in 196 cases.
2.3 Causes of extrahepatic blood supply 58 cases were extrahepatic collateral circulation (29.6% ) due to embolization (51 cases) or occlusion of the hepatic artery after surgical hepatic artery ligation (7 cases), and the remaining 138 cases were primary extrahepatic arterial blood supply, accounting for 70.4%. The extrahepatic arterial supply was closely related to the primary site and size of the cancer foci, and the success rate of extrahepatic supply branch cannulation was 92.7% (182 cases).
2.4 Relationship between extrahepatic blood supply and HAE
2.4.1 Hepatic artery patency Extrahepatic collateral branch supply A total of 138 cases (70.4 ) were found, 67 cases (48.6% ) at the 1st HAE and 71 (51.4%) at the 2nd and subsequent ones, P>0.05.
2.4.2 Collateral branches of the extrahepatic artery with occlusion or stenosis of the hepatic artery 51 cases (26.0%) of blood supply were found. 3 cases (5.9% ) were found at the 1st HAE, while 48 cases (94.1% ) were found at the 2nd and thereafter, P<0.01 for comparison between the two groups.
2.5 The source of extrahepatic blood supply and the site of mass development The extrahepatic arterial blood supply was closely related to the primary site and size of the cancer foci, and they all followed the principle of proximity: the right subdiaphragmatic or adrenal artery mainly supplied VII , VIII segmental hepatocellular carcinoma, the gastroduodenal and omental arteries mainly supplied IV, V, VI segmental carcinoma, and the left subdiaphragmatic or left gastric artery mainly supplied II ,III, IV segmental hepatocellular carcinoma, etc.
3, Discussion
3.1 Classification of extrahepatic blood supply
In clinical practice, the extrahepatic arterial blood supply of hepatocellular carcinoma is divided into three main types according to the mechanism of its occurrence.
3.1.1 Normal hepatic artery variants, i.e. alternative hepatic arteries such as right hepatic artery from superior mesenteric artery, right hepatic artery from abdominal trunk and left hepatic artery from left gastric artery.
3.1.2 Parasitic blood supply Independent of the number of HAE procedures and hepatic artery patency means that these extrahepatic blood supplies are already present in the presence of normal hepatic arteries, such as the right subphrenic artery and the adrenal artery. Therefore, they can be detected by imaging at the first HAE.
3.1.3 Extrahepatic collateral circulation supply The extrahepatic collateral circulation is open due to stenosis or occlusion of the hepatic artery. For example, gastroduodenal and omental arteries, pancreaticoduodenal artery arch, right colonic artery, internal mammary artery and intercostal artery are all included in this category.
3.2 Discussion on the mechanism of extrahepatic arterial blood supply in hepatocellular carcinoma and its basic rules
3.2.1 Hepatic artery variability The variability of extrahepatic blood supply is mainly congenital and developmental, and has no obvious relationship with the location, size and number of embolization of the mass.
3.2.2 Relationship between extrahepatic blood supply and patency of the intrinsic hepatic arteries
In this study, it was found that the right subphrenic and adrenal arteries (34.7%) and the gastroduodenal artery and omental artery collateral branches (26.0% ) were two cases, and the statistical test showed P<0.05. Therefore, it is suggested that there is a clear relationship between these two types of extrahepatic blood supply and the patency of the hepatic artery, i.e., the right subphrenic and adrenal arteries are mostly involved in partial blood supply to the tumor when the hepatic artery is patency; in comparison In contrast, those with collateral branches of the gastroduodenal artery and omental artery involved in blood supply were formed after a period of time following stenosis or occlusion of the hepatic artery.
3.2.3 Pattern of extrahepatic arterial blood supply in hepatocellular carcinoma
The results of this study showed that the parasitic blood supply or the extrahepatic collateral circulation blood supply of hepatocellular carcinoma were most closely related to the site of cancer. The overall probability is that if the mass is located in the marginal area of the liver, such as adjacent to the anterior or posterior abdominal wall (bare liver area), the right kidney or adrenal gland or the top of the right diaphragm, and if the mass is larger and has more embolizations, the extrahepatic blood supply is more likely to occur; conversely, if the mass is located in the marginal area of the liver parenchyma away from the liver, and if the mass is smaller and has fewer embolizations, the extrahepatic blood supply is less likely to occur.
3.2.4 Possible mechanisms of extrahepatic arterial blood supply in hepatocellular carcinoma
It is generally believed that hepatic tumors located in the right outer lobe of the liver can obtain blood supply from the right inferior phrenic artery through the right deltoid ligament and the right coronary ligament. The greater omentum is a free tissue in the abdominal cavity, and when the tumor in the lower part of the liver, especially when it protrudes into the abdominal cavity, the greater omentum is very easy to adhere to it, thus obtaining the blood supply from the omental system. Therefore, tumors of the right liver can obtain blood supply of the right renal system through this gap or by direct invasion, and the blood supply can come from the adrenal gland or the perinephric artery.
Tumors of the left liver can obtain blood supply from the left inferior phrenic artery through the left triangular ligament and left coronary ligament. There are many anastomosing branches between the left hepatic artery and the left gastric artery, and the tumor of the left liver may also obtain blood supply to the stomach through the small omental sac or direct invasion. In addition, the common hepatic artery is occluded after repeated HAE, and hepatocellular carcinoma may also obtain blood supply from superior mesenteric artery, pancreaticoduodenal artery arch, right middle colonic artery, and even from gonadal artery.
3. 3 Interventional treatment countermeasures for extrahepatic arterial blood supply of hepatocellular carcinoma
3.3.1 Searching strategy Most of the arterial blood supply of hepatocellular carcinoma originates from the celiac artery and superior mesenteric artery, so superior mesenteric artery and celiac artery imaging should be routinely performed, and the catheter should not be inserted too deeply, and DSA should be performed at the opening to avoid missing the blood supply branch of proximal origin and affecting the efficacy of interventional treatment.
In the process of DSA, if the tumor in the parenchymal stage is incompletely visualized, or the embolization shows eccentric defect of iodine oil deposition in the tumor, or there is obvious defective area of tumor staining compared with CT images, or there is a large defect compared with previous imaging lesions, as well as when the tumor is huge or extravasated, it indicates the possible existence of extrahepatic arterial blood supply. It is appropriate to search for its blood supplying branch according to the above mentioned frequency and perform interventional treatment respectively.
3.3.2 Specific search methods When the tumor is located in the posterior superior right lobe, right phrenic arteriogram should be done routinely; when the tumor is located in the posterior inferior right, right renal arteriogram should be added. When the tumor is huge and located in the middle and lower right lobe, gastroduodenal artery, omental artery, pancreaticoduodenal artery and right colonic artery should be done; when the tumor is located in the left lobe, left gastric artery and left phrenic artery should be done. If the tumor is located in the left lobe, left gastric artery and left phrenic artery should be done. If the extrahepatic responsible artery cannot be found by the above methods, upper mid-abdominal CTA can be performed using contemporary multi-row spiral CT (MSCT) vascular imaging technology to provide prior multifaceted information on the origin and opening orientation of the extrahepatic responsible artery to provide guidance for cannulation.
3.3.3 Prevention of hepatic artery stenosis and occlusion There are many causes for the formation of extrahepatic arterial supply in hepatocellular carcinoma, and hepatic artery stenosis and occlusion is a very important cause. Once occlusion of the common or intrinsic hepatic artery occurs, it is very easy to form the collateral circulation of the extrahepatic artery for blood supply, which undoubtedly causes considerable difficulties for the subsequent effective interventional treatment.
Therefore, gentle movements should be made during intubation to avoid damage to the intima of the proximal hepatic artery and the primary branches, and super-selective tumor supply branch embolization should be done to reduce the occurrence of extrahepatic artery supply due to occlusion caused by chemical and mechanical injury. If cannulation with conventional catheter technique fails, microcatheter can be used. Because of its low mechanical stimulation of the vessel, it can effectively prevent endovascular injury. In cases with multiple supply branches, separate superselective cannulation for HAE should be performed.
When the hepatic artery is too sinuous and twisted or severely angulated, HAE can be performed without embolization or with simple chemotherapeutic perfusion in the proximal trunk artery or with spring-loaded embolization of the gastroduodenal artery, and can be combined with non-vascular interventions such as anhydrous alcohol injection, microwave or radiofrequency ablation to improve the outcome.
In surgical patients, hepatic artery ligation should be strongly discarded, which is as important as the above interventions to prevent hepatic artery stenosis and occlusion as it is to reduce the collateral circulation of the extrahepatic artery. These measures can increase the potential for endovascular hepatic artery interventions to prevent hepatic artery occlusion and thus improve clinical outcomes and long-term survival in these patients.