Inferior Phrenic Artery Anatomy and Clinical Significance
Welcome to our dedicated webpage on the intricate anatomy and clinical significance of the Inferior Phrenic Arteries (IPAs). This resource provides a comprehensive overview of the origins, variations, and clinical implications of the IPAs, essential for specialists in radiology, surgery, and interventional procedures.
Our in-depth analysis delves into the unique anatomical characteristics of the IPAs, highlighting their origins – ranging from a common trunk to distinct sources for the Right and Left IPAs – and their proximity to major arteries such as the celiac artery, renal arteries, and superior mesenteric artery. We explore the rarest anatomical variations observed in IPAs and the significance of these findings in clinical practices, particularly in the management of Hepatocellular Carcinoma (HCC) and in scenarios involving gastrointestinal bleeding and hepatic neoplasms.
| Category | Details | Other Keypoints |
|---|---|---|
| Origin of IPAs | Common: - Aorta (Originates from anterior, lateral, or posterior portion of aorta - 29.5% of patients) or - Celiac trunk (as a common trunk or independently): Trifurcation in celiac axis (classical anatomy seen in 89% of population with IPA origin from celiac axis). Other Variations include: Hepato-splenic truncus (5.4%), gastro-splenic truncus (2.8%), hepato-splenic-mesenteric truncus (0.3%), hepatogastric truncus (0.1%), celiac-mesenteric truncus (0.1%), no celiac truncus (0.1%), unclassified group (2.2%). | Uncommon: - Renal artery (In cases with multiple renal arteries, IPA was observed to arise from the upper renal artery.) - Left gastric artery (LGA), - Hepatic artery, - Superior mesenteric artery (SMA), - Contralateral IPA. |
| Branching patterns | RIPA (Right IPA) Anatomy: - Anterior (ascending): upper and anterior part of the diaphragm, - Posterior (descending): Lower part of diaphragm, - Superior adrenal, - Azygoesophageal: related to systemic-to-pulmonary shunt, - Pericardio-phrenic: Supply to pericardium | LIPA (Left IPA) Anatomy - Superior falciform ligament artery (Sappey superior artery): superior and anterior portion of the liver (segment IV), can be connected with both the IPAs and the internal mammary arteries - Anterior (ascending): upper and anterior part of the diaphragm, - Posterior (descending): lower part of diaphragm, - Superior adrenal, - Accessory gastric: supply gastric cardia and distal oesophagus, Significance: - Significance in Gastrointestinal Bleeding - LIPA provides blood supply to gastroesophageal junction. - Anastomoses: LIPA with transdiaphragmatic collaterals and coronary artery, medial branch of LIPA with pericardiophrenic, musculophrenic arteries. |
| HCC Supplied by IPA | - IPAs supply HCCs invading diaphragm or via capsular arteries. - IPA diameter exceeding 2.5 mm, have been considered a sign of collateral supply to tumor by IPA | - Relevant for HCCs in contact with diaphragm or post hepatic artery damage. - IPAs serve as important collateral blood supplies in hepatic neoplasms. |
| Specific Catheters Used | - Rösch Hepatic catheter, - Rösch splenic catheter, - Simmons 1 catheter, - Mikaelsson catheter | Catheter used with modification (like side hole creation) - Shepherd’s hook catheter, - Twist catheter |
| Catheterization Techniques | - Shepherd’s Hook Technique: Used for difficult catheterizations, involving a guidewire bent into a shepherd's hook shape. | - Side Hole or Cleft Catheter Technique: Involves creating a side hole in a catheter for targeted delivery. |
| Occlusion of IPA Orifice (antegrade blood flow may be absent) | - Causes: Atherosclerosis, intimal damage. - External compression: Median arcuate ligament syndrome, diaphragm compression. - Reconstitution: Dorsal pancreatic artery, adrenal arteries, left gastric artery, contralateral IPA. | - Collateral approaches often long and tortuous, posing risks of incomplete treatment or vessel dissection. - Selection of less tortuous routes for chemoembolization critical. - Use of micro balloon catheter and metallic coil for blood flow control. |
| Additional Technical Details | - Use of microballoon catheters and metallic coils in specific cases. - Precise manipulation of guidewires and catheters to avoid vessel dissection. | - Attention to anastomosis between Sappey superior artery and IPAs/internal mammary arteries. |
| Embolization via IPA (as selective as possible) | Chemoembolization Variants (TACE for HCC) - Doxorubicin (50 mg in 2.5 mL contrast media mixed with 10 mL iodized oil). - Epirubicin and mitomycin C (30 mg epirubicin, 6 mg mitomycin C mixed with 10 mL iodized oil). - Additional embolisation can be performed using different agents. | Radioembolization Considerations (TARE for HCC) - Lung shunt fraction assessment with technetium 99m macroaggregated albumin. - Dosage and microsphere type (glass or resin) based on Medical Internal Radiation Dose method - Antegrade blood flow must be established with contrast injection prior to radioactive microsphere delivery. |
| Complications and Management | - Shoulder pain, - Diaphragmatic weakness, - Atelectasis, - Pleural effusion, - Hemoptysis, - Cerebral oil embolism. | Complication Management: - Shoulder pain management with lidocaine. - Chronic hiccups treatment with medication (baclofen, gabapentin, metoclopramide) or nerve stimulation. |
| Systemic-to-Pulmonary Shunt Management | - Shunts often present in chronic pleural disease or pulmonary infection cases. - Angiographic visualization of peripheral pulmonary arteries and veins. - Precautions during embolization to avoid particle leakage into pulmonary vein. | Pulmonary Complication Prevention - Superselective catheterization or preemptive embolization of systemic-to-pulmonary shunt. - Caution with radioactive microsphere infusion in presence of shunts. |
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