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Adv. Vas. Son.
Test 3 Abdominal Doppler Transplants
| Question | Answer |
|---|---|
| What are some common causes of end stage renal disease? | Diabetes (most common cause of kidney transplant), Autosomal dominant polycystic kidney disease, Glomerulonephritis, HTN, Atherosclerosis, Systemic lupus erythematous |
| Why is there currently an organ shortage? | Shortage has resulted in loosening of criteria for decreased donors (DD), & Increased use of living related donors (LRD) |
| Graft survival rates continue to ____? | Improve |
| What are the risk factors for graft loss? | # of HLA matches (human leukocyte antigen), ↑ed age of donors & recipients, African-American use, Cold ischemic tissue >24 hrs, Diabetic nephropathy as cause of recipient's failure |
| Signs of graft failure are what? | Anuria, Rising serum creatinine level, Pain, Tenderness, Fever, Chills, Elevated white blood cell count |
| Where are most transplants placed? | Extraperitoneally in the right iliac fossa |
| Donor main renal artery (with patch of aortic wall in DD) is what? | Anastomosed to the recipient's external iliac artery, Use of patch reduces renal artery stenosis |
| Donor renal veins is what? | Anatomosed to the recipient's external iliac vein |
| What is an Ureteroneocystostomy? | It is performed to connect to ureter to the bladder, Implantation of the donor ureter into the dome of the bladder above the native ureteral orifice (UJV) |
| External drains are commonly placed where? Why? | Commonly paced next to the kidney, Reduces the incidence of lymphoceles that may compress the renal parenchyma or vascular/ureteral anastomoses & cause graft dysfunction |
| Ureteral stents placed form intrarenal collecting system into t=the bladder to what? | Reduce likelihood of ureteral scarring or necrosis |
| What happens to the native kidneys? | They're left in place |
| Transplanted kidney is usually what? | Superficially located and runs with the axis of the incision, Hilum orientated inferiorly and posteriorly |
| Length and width should be what? | Accurately measured, volume measurement may be required |
| Transplanted kidney should look like what? | A normal kidney in shape and echotexture |
| Color and Spectral Doppler are obtained from? | Main Renal A: anastomosis, Prox, & distal, EIA: superior to anastomosis, Main Renal V:w/ venous anastomsis, EIV @ level of anastomosis, Intraparenchymal renal Vs &As (signals should be obtained from upper, mid, & lower poles) |
| NORMAL arterial wavefroms: | Low-resistance w/ continuous forward flow, RI<0.7 (important to measure EDV correctly in order to accurate calc), Sharp systolic upstroke w/ an acceleration time <70-80 msec |
| Technical considerations & pitfalls: | Use harmonic &/ or compound imaging to improve image quality, Adjust scare, & gain for proper fill in, Move baseline, & adjust other spectral Doppler setting for appropriate WF recognition & measurement |
| Patients with graft dysfunction most commonly present with nonspecific signs and symptoms like: | Renal failure, Pain, and Evidence of infection |
| What is the goal of the ultrasound? | To help differentiate between failure due to medical issues and those that require intervention |
| Diagnosis Transplant Rejection results from: | An attack by the immune system on the transplanted organ |
| 3 types: | Hyperacute: Occurs immediately postop due to presence of preformed antibodies, Acute: Occurs about 2 weeks postop,& Chronic |
| Rejection is suspected with one or more of the following: | Sudden cessation of urine output (anuria), ↓ed urine output (oliguria), ↑ed serum creatinine, protein, or lymphocytes in urine, HTN, Swelling or tenderness of the graft |
| What is used for definitive diagnosis? | Biopsy |
| Acute Tubular Necrosis is caused by what? | Ischemia |
| Acute Tubular Necrosis is more common in who? | DD transplants than in LRD |
| Risk facts for ATN include: | Prolonged ischemia time, Hypotension or blood loss during surgery, Prolonged ICU time or severe illness of donor, Harvest from a non♥ beating donor |
| When does ATN occur? | In postop period (usually w/in 2-3 days) |
| What happens with ATN? | PT may require dialysis until kidney starts to function properly, Diminished diastolic flow in segmental arteries may be an indicator, Biopsy is definitive diagnosis |
| Fluid collections, what are the most common? | Hematomas, Urinomas, & Lymphoceles, Size & location should be documented on ultrasound exam |
| Hematoma facts: | Found immediately postop, Size, echotexture & location will vary(may be located near biopsy site), Followed to ensure decrease in size |
| Acute hematomas will: | Be echogenic becoming more heterogenous and complex with age |
| What is an Urinoma? | Form when urine leaks from either ureteral anastomosis or focal area of ureteral necrosis, Usually discovered w/in 1st few weeks posttransplant, Suspected w/↓ed urine output or if urine leakage is found from surgical site |
| Urinomas on ultrasound: | Located between kidney & bladder, Typically anechoic, May contain septations if infection has occurred |
| What is a Lymphocele? | Occurs w/ surgical disruption of the lymphatic chain, Usually appears 4-8 weeks posttransplant & are discovered incidentally, Can compress ureter causing obstruction or become super infected (both require drainage) |
| Lymphocele on ultrasound: | Well-drained, anechoic fluid collections, May contain multiple thin septations |
| How to distinguish a Lymphocele from Urinoma? | Urinomas occur w/in first few weeks; Lymphoceles occur after first month |
| Diagnosis Hydronephrosis: Mild dilatation is___? | NORMAL posttranplantation |
| What happens with mild dilatation? | Denervated kidney loses its automatic tone, Intrarenal collecting system will dilate, ASX @ this point |
| True hydronephrosis may develop due to: | Ureteral stricture from postsurgical scarring, ischemia, or rejection, Blood clot in ureter, Bladder distention, ↓ed ureteric tone or compression from surrounding structures, Posttransplant lymphoproliferative disorder |
| Vascular complications may occur when? | Immediately postop or may have delayed presentation |
| Immediately postop what can occur? | Venous or arterial thrombosis can occur, Suspected w/ sudden anuria or acute onset of pain in region of transplant |
| If it is an emergent situation what does it require? | Requires quick diagnosis and intervention |
| Arterial Thrombosis risk factors include: | Hypercoagulable states, Hypotension, Intraoperative trauma, Mismatch of vessel size, Vascular kinking |
| Severe acute rejection or emboli (rare) may result in what? | Occlusion or thrombosis of intraparenchymal renal arteries |
| With Arterial thrombosis what would be some sonographic findings: | Intraluminal echoes, Absence or arterial and venous flow on color, power, or spectral Doppler, of intrarenal or main renal arteries & veins, Make sure Doppler controls are sensitive to slow flow states |
| Venous Thrombosis facts: | Rare event, Most commonly occurs w/in first 24-48 hrs postop, PT may complain of pain or discomfort over transplant due to kidney swelling |
| causes of Venous thrombosis: | Surgical complications, Compressions by lymphocele or other fluid collections, Propagation of Iliac vein thrombus, Hypotension, Hypercoagulable states, Torqueing of vascular pedicle |
| Venous Thrombosis Sonographic findings include: | Enlargement of kidney, ↓ed renal cortical echogenicity, Enlarged main renal vein; may or may not contain low-level echoes, Absence of flow on color,power, or spectral doppler, Presence of reversed flow in renal As (biphasic WF) |
| Renal Artery Stenosis facts: | MOST COMMON vascular complication, PTs present w/ severe uncontrolled HTN |
| Renal Artery Stenosis causes: | Postsurgical scarring or dissection, Intimal hyperplasia, Progressive atherosclerosis, Rejection |
| What are the risk factors with Renal Artery stenosis? | Vessel diameter mismatch, or complex arterial reconstructions |
| Renal Artery stenosis occurs more commonly in __? | LRD and Pediatric transplants |
| Renal Artery stenosis may occur secondary to what? | Twisting or kinking of main renal artery, Excessive length of renovascular pedicleputs PT at risk |
| Renal Artery stenosis sonographic findings: | Elevated PSV>220-250 cm/s, Renal Artery to EIA ratio >2.0-3.0, Poststenotic turbulence, Tardus parvus WF pattern distally |
| Color Doppler can help with what? | Visualize areas of aliasing and sharp bends associated with kinking |
| Postbiopsy vascular complications: | Abnormalities include arteriovenous fistula (AVF), or pseudoaneurysm (PSA) |
| AVF facts: | Color aliasing present in area as well as color bruit, Feeding artery will have high Vel in systole &diastole, Draining V will demonstrate pulsatile, high Vel, Arterialized flow |
| Postbiopsy vascular complications PSA: | Anechoic, round area w/in renal parenchyma, Swirling flow noted on color ("yin-yang" sign), To-&-Fro Doppler signal in the neck |
| Most AVFs & PSAs are what? | Benign & are followed until they resolve, May need intervention if they are larger than 2cm, are expanding or extrarenal in location |
| What a PSA? | Pseudoaneurysm |
| What is the second most commonly transplanted organ after the kidney? | Liver |
| Why is ultrasound an important tool for evaluating liver transplants? | Readily available, no risks or contraindications, Sensitive test for detection of vascular complications, postop fluid collections, & biliary complications |
| What are the MOST common indications for Liver Transplantation: | Hep C, Alcohol liver disease, Cryptogenic cirrhosis, Primary biliary cirrhosis, Primary ciliary sclerosing cholangitis, Hemachromatosis, Wilson's disease, Autoimmune hepatitis, Acute or fulminant liver failure, Hepatocellular carcinoma (early stage) |
| What are contraindications or exclusion criteria for Liver transplantation: | Extrahepatic malignancy, Untreated infection, Anatomic abnormality, Hepatocellular carcinomathat has metastasized or is >5cm, Advanced cardiopulmonary disease, Active substance abuse, End-stage Hep B, Old age, Cholangiocarcinoma |
| What is most commonly performed? | Orthotopic liver transplant, tranplanted organ is placed into normal anatomic position, Usually performed w/ whole liver from DDs |
| What does DD stand for? | Deceased donor |
| Due to organ shortage what is becoming more common? | Partial liver transplants from LRDs |
| What does LRD mean? | Living-related donor |
| Vascular and biliary anastomoses vary widely due to what? | Wide variation in anatomy and anomalies, Also depend on type of transplant |
| Donner common bile duct is what? | Typically anastomosed end-to-end w/ recipient common hepatic duct, |
| What may be needed if a recipients duct is diseased? | A choledochojejunostomy, the biliary system drains directly into jejunum |
| What is the anastomosis often reinforced with? | Stent |
| Arterial anastomosis is common made where? | Between donor common hepatic artery (or celiac artery) & recipient common hepatic artery, Typically uses the "fish mouth" technique- smaller vessel's wall are split & sewn over larger vessel (prevents development of postsurgical stenosis) |
| Portal Vein typically anastomosed where? | End-to-end between donor and recipient main portal vein |
| Hepatic veins are connected where? | Into IVC, Donor hepatic veins & IVC connected together to recipient IVC |
| Single-lobe LRD transplants are becoming more __? | Common |
| Right lobe donations are used in ______? | Adults |
| Left lobe donations are used in ____? | Children |
| Single-lobe LRD transplant facts: | Donor hepatic artery, bile duct, portal vein, & hepatic vein are anastomosed end-to-end or end-to-side w/ the native structures |
| Perioperative morbidity in all cases is what? | High, PTs are extremely ill and surgery is complicated |
| Why is it important to consult the surgeon or surgical report? | To determine what tpe of tranplant was used (full liver vs. single lobe), Also important to determine vascular anastomoses & anomalies used |
| Most common cost of cause transplant loss is what? | Graft failure/rejection followed by biliary complications, Vascular causes are next most common |
| What is used to look for signs of failure? | Serial ultrasound exams |
| Signs of rejection include: | Abnormal liver function tests, Ascites, Pleural effusion, Varices, Sepsis, Fever, Biliary obstruction, Leakage, Infection, Splenomegaly |
| Since SX are nonspecific what is needed? | Imaging critical in evaluation of SX liver |
| NORMAL transplant findings include: | Homogenous appearance, Appropriately sized (for type of transplant), Normal appearing biliary system w/out dilatation (may appear thickened if stent is in place), Periheptic fluid is normal early postop but should resolve w/in days |
| Considerations & pitfalls: | Many times all Doppler measurements are teken from intercostal approach, Presence of high resistance signal immediately postop, Postop scarring makes exam difficult, Scanning environment may be suboptimal (@ bedside) |
| What is the ideal way to evaluate portal system as allows better angle to flow, and Will enhance Doppler shift and color fill-in? | Intercostal approach |
| High resistance signal immediately postop is a NORMAL finding thought to be due to what? | Liver swelling/↑ in intrahepatic pressure & vascular resistance, Daily Doppler exams should reveal improvement in RI, If RI doesn't improve, arterial thrombosis should be suspected |
| Why may the scanning environment be suboptimal? | PT often will be intubated & have multiple lines & bandaging, Intercostal scanning technique often only method that can be used |
| Vascular complication are harder to/easier to detect by ultrasoun? | Easier |
| Ultrasouns does/does not play a role in definitive diagnosis of rejetion? | Does NOT |
| Ultrasound is the procedure of choice for: | Initial evaluation of potential fluid collections, abnormalities of the biliary tree, & vascular complications |
| Common Nonvascular postop liver transplantation complications other than Recurrent malignancy & Lymphopproliferative disorder: | Bile duct obstruction, Anastomotic bile dut obstruction, Anastomotic stenosis/stricutre, Stone formation, Bile leak/Biloma, Biliary necrosis, Cholangitis, Postop bleeding, Hematoma, Abcess, Infection, Recurrent hepatitis, Portal HTN, Splenic infarct |
| Filling defects or absence of flow present with what? | Thrombus |
| Color aliasing and spectral broadening present with what? | Stenosis |
| Hepatic artery complication are cause for what? | Immediate surgical intervention, Hepatic artery sole source of blood supply to bile ducts- lack of blood will lead to biliary necrosis & loss of transplant |
| Common vascular postop liver transplantation complications: | Hepatic A thrombosis, Hepatic A stenosis, Pseudoaneurysm, Portal V thrombosis, Portal V stenosis, IVC thrombosis, IVC stenosis, Hepatic V thrombosis, Hepatic V stenosis, Biliary iscemia due to hepatic A stenosis |
| Hepatic Artery Thrombosis (HAT) facts: | Most COMMON vascular complication |
| HAT risk factors include: | Rejection, Prolonged transport time of organ, Use of end-to-end surgical technique of hepatic artery |
| HAT sonographic findings include: | Absent or weak hepatic arterial flow, However, completely patent vessel may be difficult to visualize due to vasospasm or parenchymal swelling, Often requires imaging modality |
| Hepatic Artery Stenosis (HAS) facts: | SXs include poor liver function or biliary ischemia, Usually seen @ anastomotic site due to surgical tech, clamp injuries, perfusion catheter injuries, & interruption of vaso vasorum, ↑ed vels are noted w/ poststen turbulance & tardus parvus WFs distally |
| Hepatic Artery Pseudoaneurysm (PSA) facts: | Abnormal dilatation of ballooning of the hepatic artery either w/in the liver or extrahepatic, Doppler WF usually disorganized, High risk hemorrhage & organ failure; intervention is needed |
| Extrahepatic is usually due to what? | Disruption of intimal lining- causes dilation that can easily rupture |
| Intrahepatic is usually due to what? | Thought to be caused by core needle biopsy or infections |
| Portal Vein Thrombosis (PVT) facts: | Relatively rare finding; usually involves extrahepatic portion, PT may have early liver failure & signs of portal HTN, Requires intervention |
| PVT causes include what: | Surgical injury, Vessel length, Hypercoagulaable state |
| PVT sonographic findings: | Complete or partial flow voids w/color, Echogenic thrombus inside lumen, Low-vel scale setting must be used to detect any flow that may be present, Power Doppler should be used to verify absence of flow |
| Portal Vein Stenosis facts: | Most commonly occurs at anastomotic site; often related to surgical injury, PT often has signs of worsening hepatic function, Color & Spectral Doppler demonstrate narrowing (PSV>125 cm/s, Anastomotic-to-preanastomotic vel ratio of 3:1) |
| With Portal Vein Stenosis what is required? | Angioplasty or stent placement |
| IVC thrombosis/stenosis facts: | Rare, Associated w/ tech used to connect recipient & donor IVCS, Also ass. w/mechanical compression from fluid collection, hypercoagulability, vessel length, & retransplantation, PT often presents w/ hepatic failure |
| IVC thrombosis/stenosis on ultrasound: | Thrombus will be seen in lumen w/ associated changes in color & Spectral Doppler (signs of narrowing & Vel changes) |
Created by:
EmilyGriffin
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