Long-term survival of patients with unresectable hepatocellular carcinoma treated with transcatheter arterial chemoinfusion.

BACKGROUND: Transcatheter arterial chemoembolization (TACE) has become one of the most common treatments for unresectable hepatocellular carcinoma. Published studies of TACE report a 5-16% risk of serious complications. Compared with TACE, transcatheter arterial chemoinfusion (TACI) may have similar efficacy and fewer side effects. AIM: To examine the clinical outcomes of TACI. METHODS: We performed a retrospective cohort study of 345 consecutive TACI cases in 165 patients performed at a single United States medical center between 1998 and 2002. Primary outcomes were tumour response and survival rates. RESULTS: Only seven patients were hospitalized for more than 24 h after the procedure, and only three patients had worsening of liver function within 30 days of TACI. Survival was significantly poorer for patients with tumour-node-metastasis (TNM) IV compared to those with TNM I-III and also for patients with Child's class B/C vs. A. Following adjustment for age, gender, ethnicity and aetiology of liver diseases, independent predictors of poor survival were Child's class B/C [Hazard Ratio (HR) = 1.69, P = 0.024] and TNM IV staging (HR = 1.63, P = 0.014). CONCLUSIONS: TACI appears to be safe and effective for unresectable hepatocellular carcinoma with TNM stage I-III; randomized controlled trials are needed to compare TACI to TACE.

Development of a platform to evaluate and limit in-stent restenosis.

The objective of this work was to develop a platform to evaluate and deliver putative therapeutic agents for in-stent restenosis. Arterial stenting is applied in more than 60% of balloon angioplasties for treating cardiovascular disease. However, stented arteries encounter accelerated rates of restenosis. No prior platform has allowed evaluation or local management of in-stent restenosis without perturbing the very system being examined. A stainless steel, balloon-expandable stent was modified to serve as an ablumenal drug delivery platform. Several combinations of bioerodible polymer microspheres and gels were evaluated for channel retention under in vitro flow and in vivo conditions. A stent-anchored hybrid system prevented material embolization under all conditions. Unlike prior platforms, these stents do not alter local inflammation or in-stent plaque formation relative to conventional Palmaz-Schatz stents after in vivo deployment. The system also proved sensitive enough to detect plaque reduction with an antirestenotic agent. We conclude that a platform to evaluate and deliver therapeutic agents for in-stent restenosis has been achieved.

Impact of multidetector CT hepatic arteriography on the planning of chemoembolization treatment of hepatocellular carcinoma.

OBJECTIVES: We examined the impact of the increased sensitivity for hypervascular masses of multidetector CT hepatic arteriography on treatment decisions involving selective chemoembolization of hepatocellular carcinomas. SUBJECTS AND METHODS: Thirty patients were referred for chemoembolization of unresectable hepatocellular carcinoma. Initial selective chemoembolization plans were formulated on the basis of diagnostic biphasic CT or MR imaging. Ultrafast CT hepatic arteriography was performed using a multidetector CT scanner and selective contrast material injection into the hepatic artery. The entire liver was scanned in a single breath-hold of approximately 20 sec with a slice thickness of 1 mm. Lesions and their arterial supplies were identified, and these data were immediately used to formulate a final plan for chemoembolization. RESULTS: Hypervascular masses were detected in 29 patients. In 16 (53%) of the patients, preprocedural CT or MR imaging underestimated the number of lesions. In nine (30%) of these 16 patients, the additional lesions were detected only on CT hepatic arteriography, not on conventional angiography. CT hepatic arteriography findings had a major impact on planning the way in which chemoembolization treatment was performed. In three of the nine patients, the previously undetected lesions were treated with additional superselective chemoembolization. In the other six patients, chemoembolization was performed less selectively than originally planned. CONCLUSION: Primarily because of the high sensitivity of multidetector CT hepatic arteriography in revealing small and multifocal hepatomas, findings of this modality frequently alter treatment plans involving selective administration of chemoembolic material.

Alteplase and tenecteplase: applications in the peripheral circulation.

Alteplase (t-PA), a recombinant analogue of human tissue plasminogen activator, became the first genetically engineered thrombolytic approved by the Food and Drug Administration in 1987 for acute myocardial infarction (AMI). In addition to AMI, alteplase is currently approved for the treatment of acute ischemic stroke and pulmonary embolism, and we anticipate approval for catheter clearance in late 2001 in a 2-mg vial configuration. With the withdrawal of human neonatal kidney cell-derived urokinase, alteplase has become an alternative agent in peripheral vascular applications. Because few interventionalists had prior experience with the handling and dosage of alteplase, the Advisory Panel to the Society of Cardiovascular and Interventional Radiology established practice guidelines for use in noncoronary applications. Emerging clinical experience with contemporary dosing regimens shows a safety and efficacy profile similar to urokinase but with significantly reduced drug costs. Tenecteplase (TNK) is a genetically modified version of alteplase. TNK is the only plasminogen activator available that has shown a significantly enhanced safety profile versus alteplase in AMI. Approved for a 5-second, single-bolus injection in AMI, TNK possesses a longer half-life, increased resistance to plasminogen activator inhibitor, and improved fibrin specificity compared with alteplase. Because of its enhanced safety profile, TNK may be a desirable agent for peripheral vascular applications. Initial clinical studies with TNK in acute arterial and venous disease are ongoing. This article outlines the Advisory Panel guidelines for using alteplase and highlights features of tenecteplase.

Endovascular management of iliac vein compression (May-Thurner) syndrome.

PURPOSE: To evaluate the feasibility of endovascular techniques in treating venous outflow obstruction resulting from compression of the iliac vein by the iliac artery of the left lower extremity (May-Thurner syndrome). MATERIALS AND METHODS: A retrospective analysis of 39 patients (29 women, 10 men; median age, 46 years) with iliac vein compression syndrome (IVCS) was performed. Nineteen patients presented with acute deep vein thrombosis (DVT) and 20 patients presented with chronic symptoms. All patients presented with leg edema or pain. In the acute group, patients were treated with catheter-directed thrombolysis (120,000-180,000 IU urokinase/h) and angioplasty followed by stent placement. In the chronic group, patients were treated with use of angioplasty and stent placement alone (n = 8), or in combination with thrombolysis (n = 12). Patients were then followed-up with duplex ultrasound and a quality-of-life assessment. RESULTS: Initial technical success was achieved in 34 of 39 patients (87%). The overall patency rate at 1 year was 79%. Symptomatically, 85% of patients were completely or partially improved compared with findings before treatment. Thirty-five of 39 patients received stents. The 1-year patency rate for patients with acute symptoms who received stents was 91.6%; for patients with chronic symptoms who received stents, the 1-year patency rate was 93.9%. Five technical failures occurred. Major complications included acute iliac vein rethrombosis (< 24 hours) requiring reintervention (n = 2). Minor complications included perisheath hematomas (n = 4) and minor bleeding (n = 1). There were no deaths, pulmonary embolus, cerebral hemorrhage, or major bleeding complications. CONCLUSION: Endovascular reconstruction of occluded iliac veins secondary to IVCS (May-Thurner) appears to be safe and effective.

Internal iliac artery embolization in the stent-graft treatment of aortoiliac aneurysms: analysis of outcomes and complications.

PURPOSE: To analyze the complications of internal iliac artery (IIA) embolization in conjunction with stent-graft treatment of aortoiliac aneurysms. MATERIALS AND METHODS: Seventy-one patients with aortoiliac (n = 47) or iliac (n = 24) aneurysms were treated with endoluminal placement of stent-grafts. Thirty-two patients (31 men, one woman; mean age, 73 years; range, 56-88 years) had embolization or occlusion of one (n = 27) or both (n = 5) IIAs. Status of the IIAs and the collateral circulation was assessed by retrospective review of angiographic images. Follow-up consisted of a standardized patient questionnaire and review of radiologic and medical records. RESULTS: The mean follow-up time was 35 months (range, 5-64 months). Eleven of the 47 patients with abdominal aortic aneurysms (AAA) (23%) and 19 of the 24 patients with iliac aneurysms (79%) required IIA embolization. One patient with AAA and another with iliac aneurysm had unintentional occlusion of an IIA by extension of the stent-graft over their origins. A total of seven patients had bilateral occlusion of the IIAs after the procedure. Additionally, the inferior mesenteric arteries (IMAs) of two other patients with AAA were also embolized. In six patients, all three vessels were occluded after placement of the stent-grafts. Symptoms were reported in nine of the 20 (45%) patients with iliac aneurysms and in three of the 12 (25%) patients with AAA. Symptoms consisted of buttock claudication (nine of 32, 28%), new sexual dysfunction (two of 16, 12%), and transient urinary retention (3%). Seven of the claudicants had resolution of symptoms after a mean interval of 14 months (range, 1-36 months). There were no instances of bowel ischemia, neurologic sequelae, or buttock necrosis related to these procedures. CONCLUSION: Embolization of the IIA is associated with symptoms in a significant number of patients. While symptoms are transient in most patients, they can be problematic. Efforts should be made to preserve the pelvic circulation if possible.

Stent-graft therapy for subclavian artery aneurysms and fistulas: single-center mid-term results.

PURPOSE: To evaluate the potential of covered stents to replace surgery in the treatment of subclavian artery aneurysms and traumatic injuries. MATERIALS AND METHODS: Nine patients (five men, four women; age range, 20-83 years; mean, 54 years) with subclavian artery aneurysms (n = 5) or fistulas (n = 4) were treated with stent-grafts. All devices used were custom-made, consisting of polytetrafluoroethylene (PTFE)-covered Palmaz (n = 5), Wallstent (n = 2), Z stents (n = 8), or a polyester-covered Z stent (n = 1). One patient was lost to follow-up after 2 months. All others were followed up with clinical evaluation, computed tomography (CT), and/or ultrasound. RESULTS: All devices were deployed successfully with exclusion of the aneurysms and fistulas. There were two procedure-related complications (22%), consisting of groin pseudoaneurysms requiring surgical repair 3 and 9 days after the procedure. One of those patients required additional oral antibiotic therapy for a postsurgical groin wound infection. One patient developed a stenosis at 12 months, which required angioplasty. The stent-graft thrombosed in one patient because of a kink 2 months after placement, which was successfully treated by thrombolysis and placement of a Wallstent. The primary and secondary patencies are 89% and 100%, respectively, after a mean follow-up of 29 months (2-66 mo). CONCLUSION: Mid-term results of stent-graft therapy of subclavian artery aneurysms and fistulas are encouraging, with low morbidity and excellent clinical outcome.

Chronically occluded inferior venae cavae: endovascular treatment.

PURPOSE: To report the results of endoluminal recanalization and stent placement in patients with chronic occlusions of the inferior vena cava (IVC). MATERIALS AND METHODS: Seventeen consecutive patients (12 male, five female patients; mean age, 40.6 years; age range, 15-77 years) with chronic IVC occlusions were treated during a 6-year period. The mean duration of symptoms was 32 months. Underlying active malignancy was the cause of occlusion in four patients. Five patients with superimposed acute thrombus underwent catheter-directed thrombolysis prior to IVC recanalization. Clinical patency was defined as absence or improvement of symptoms. Clinical follow-up was supplemented with ultrasonography, vena cavography, or both in 10 patients. RESULTS: Technical success was achieved in 15 (88%) patients. Additional thrombolytic therapy and stent placement was needed in two patients to maintain patency at 4 and 6 months after the procedure. Twelve patients had IVCs that remained patent after a mean follow-up of 19 months for a primary patency rate of 80%. The primary assisted patency rate was 87% (13 of 15). There were four deaths owing to underlying disease 6-21 months after the procedures. There were no procedure-related complications. CONCLUSION: Endoluminal recanalization and stent placement in chronically occluded IVCs has a good intermediate-term outcome and should be considered in patients who have symptoms and who often do not have adequate alternative therapy.

Diagnostic yield of MR-guided liver biopsies compared with CT- and US-guided liver biopsies.

PURPOSE: To compare diagnostic yield and complication rates of magnetic resonance (MR)-guided versus computed tomography (CT)- and ultrasound (US)-guided liver biopsies. MATERIALS AND METHODS: MR-, CT-, and US-guided liver biopsies performed between 9/96 and 9/98 were compared. Sixty patients (21 men and 39 women, mean age 60 years) underwent MR-guided biopsy of liver lesions. Thirty patients (16 men and 14 women, mean age 59 years) underwent CT-guided biopsy. Eighteen patients (seven men and 11 women, mean age 50 years) underwent US-guided biopsy. MR procedures were performed in an open-configuration 0.5-T Signa SP MR unit. Lesion localization used standard T1 and T2 sequences, whereas biopsies were performed with multiplanar spoiled gradient recalled echo and fast gradient recalled echo sequences. A coaxial system with an MR-compatible 18-gauge stabilizing needle and a 21-gauge aspiration needle was used to obtain all samples. In CT and US procedures, a 19-gauge stabilizing needle and a 21-gauge aspiration or a 20-gauge core biopsy needle were used. A cytotechnologist was present to determine the adequacy of samples. RESULTS: MR had a diagnostic yield of 61%. CT and US had diagnostic yields of 67% and 61%, respectively. No serious complications were reported for MR and US procedures. Two CT biopsies resulted in postprocedural hemorrhage. One patient required surgical exploration and died. CONCLUSIONS: MR-guided biopsy of liver lesions with use of a 0.5-T open-configuration magnet is safe and accurate when compared with CT and US. No statistical difference was observed between the diagnostic yield of biopsies performed with MR, CT, and US guidance. MR enabled biopsy of a number of lesions in the hepatic dome and lesions with low contrast, which would normally be difficult to sample safely with use of CT or US.

A comprehensive approach using MR imaging to diagnose acute segmental mesenteric ischemia in a porcine model.

OBJECTIVE: Acute mesenteric ischemia is a lethal disease that lacks a noninvasive diagnostic test. We evaluated the abilities of contrast-enhanced MR angiography, MR oximetry, and real-time interactive MR imaging to diagnose segmental mesenteric ischemia in a porcine model. MATERIALS AND METHODS: Segmental mesenteric ischemia was created by subselective Gelfoam embolization of the mesenteric circulation in eight pigs. Conventional digital subtraction angiography (DSA), MR oximetry, and real-time interactive MR imaging of the small bowel were performed before and after embolization. Changes in the perfusion pattern seen on DSA established the regions of true ischemia. Postembolization DSA and MR angiography were compared with this gold standard. RESULTS: Both MR angiography and DSA had high sensitivity (91% and 100%, respectively) for detecting ischemic regions. The difference was not statistically significant (p > .2). MR angiography yielded lower specificity than DSA (80% and 90%, respectively; p < .01). After embolization, the oxygen saturation in the superior mesenteric vein (SMV) dropped significantly (p < .005). After embolization, the SMV also showed oxygen saturation significantly lower than that in the inferior vena cava (p < .005). In two of the animals, segmental hypomotility of the small bowel was observed. CONCLUSION: MR oximetry is capable of detecting oxygen desaturation caused by segmental ischemia. A loss of oxygen saturation in the SMV relative to that in the inferior vena cava provides a convenient marker of mesenteric ischemia. Contrast-enhanced MR angiography has sensitivity and specificity approaching those of DSA. Both MR techniques hold promise for the detection of acute mesenteric ischemia.

Management of misplaced or migrated endovascular stents.

PURPOSE: To report experience with techniques for management of misplaced or migrated endovascular stents. MATERIALS AND METHODS: During a 5-year period, percutaneous management of 27 misplaced or migrated endovascular stents (16 Palmaz, 11 Wallstents) in 25 patients was attempted. The 17 venous and 10 arterial stents were rescued from the aorta (n = 9), inferior vena cava (IVC) (n = 4), transjugular intrahepatic portosystemic shunt/IVC (n = 2), right atrium (n = 3), right ventricle (n = 2), pulmonary artery (n = 2), iliac vein (n = 2), iliac artery (n = 1), superior vena cava (n = 1), and superior mesenteric vein (n = 1). RESULTS: Stent management was successful in 26 of 27 cases (96%). Eleven stents were removed percutaneously, two were repositioned and removed with a minor surgical procedure, and 13 were repositioned and deployed in a stable alternate location. The only complication was the development of tricuspid insufficiency in the single case in which the procedure failed (4% complication rate). This patient's stent was eventually surgically removed from the right ventricle. CONCLUSION: Misplaced or migrated endovascular Palmaz and Wallstents can be effectively managed with few complications by using a variety of percutaneous techniques.

Endovascular treatment of hepatic venous outflow obstruction after piggyback technique liver transplantation.

BACKGROUND: The piggyback technique of orthotopic liver transplantation is an attractive alternative that preserves the recipient inferior vena cava and allows uninterrupted venous blood return during the anhepatic phase. As with other transplantation techniques, the vascular anastomoses required by the piggyback technique can develop strictures. METHODS: Review of records of 264 piggyback transplantations revealed two cases of delayed-onset hepatic venous obstruction from anastomotic strictures. Both patients also had symptoms of inferior vena cava obstruction, with azotemia and lower extremity edema. Both patients were treated percutaneously with balloon-expandable stents. RESULTS: Rapid, dramatic resolution of symptoms was achieved in both patients. Patients remain completely asymptomatic at 39 and 3 months of follow-up. CONCLUSIONS: Hepatic venous anastomotic strictures in recipients of piggyback technique transplants are a very uncommon complication. They may be easily and effectively treated by minimally invasive endovascular intervention.

Recurrent TIPS failure associated with biliary fistulae: treatment with PTFE-covered stents.

PURPOSE: To evaluate the efficacy of covered stents for the treatment of transjugular intrahepatic portosystemic shunt (TIPS) obstruction in human subjects with identified or suspected biliary fistulae. METHODS: Five patients were treated for early failure of TIPS revisions. All had mid-shunt thrombus, and four of these had demonstrable biliary fistulae. Three patients also propagated thrombus into the native portal venous system and required thrombolysis. TIPS were revised in four patients using a custom-made polytetrafluoroethylene (PTFE)-covered Wallstent, and in one patient using a custom-made PTFE-covered Gianturco Z-stent. RESULTS: All identified biliary fistulae were successfully sealed. All five patients maintained patency and function of the TIPS during follow-up ranging from 2 days to 21 months (mean 8.4 months). No patient has required additional revision. Thrombosis of the native portal venous system was treated with partial success by mechanical thrombolysis. CONCLUSION: Early and recurrent failure of TIPS with mid-shunt thrombosis, which may be associated with biliary fistulae, can be successfully treated using covered stents. Stent-graft revision appears to be safe, effective, and potentially durable.

Descending thoracic aortic aneurysm: thoracic CT findings after endovascular stent-graft placement.

PURPOSE: To evaluate the usefulness of thoracic computed tomography (CT) after placement of an endovascular stent-graft for the treatment of descending thoracic aortic aneurysm. MATERIALS AND METHODS: From 1992 to 1996, 85 patients with thoracic aortic aneurysm underwent stent-graft placement. In 63 patients, thoracic CT scans were obtained both before and within 10 days after placement. The CT findings were retrospectively studied, and their clinical effect analyzed. In 20 of 63 patients, long-term follow-up CT findings were also evaluated. RESULTS: After stent-graft placement in the 63 patients, CT demonstrated an increase in pleural effusion in 46 (73%), periaortic changes in 21 (33%), perigraft leak in 13 (21%), atelectasis in six (10%), mural thrombus within the stent-graft in two (3%), and new aortic dissection in one (2%). The mean maximum diameter of the aneurysm was 58.8 mm before and 60.0 mm after stent-graft insertion. Sixty-two (98%) patients were successfully treated until discharge. Interventional procedures were performed to eliminate the leakage into the aneurysm sac in 10 patients with perigraft flow depicted at CT. Other complications were managed conservatively. CONCLUSION: Thoracic CT is useful in the treatment of patients after stent-graft insertion for the management of descending thoracic aortic aneurysm.

1999 Gary J. Becker Young Investigator Award. MR-guided transjugular portosystemic shunt placement in a swine model.

PURPOSE: To evaluate the performance of portal venous puncture with use of magnetic resonance (MR) guidance, and to place a transjugular intrahepatic portosystemic shunt (TIPS) in a swine model. MATERIALS AND METHODS: A study of 12 swine was performed to evaluate the ability of interventional MR imaging to guide portal vein puncture and TIPS placement. Six swine had catheters placed in the right hepatic vein under C-arm fluoroscopy. A nitinol guide wire was left in the vein and the animals were then moved into an open configuration MR imaging unit. A TIPS needle set was used to puncture the portal vein using MR fluoroscopy. The animals were transferred to the C-arm, and venography confirmed portal vein puncture. A follow-up study was performed in six additional swine to place a TIPS using only MR imaging guidance. MR tracking was used to advance a catheter from the right atrium into the inferior vena cava. Puncture of the portal vein was performed and a nitinol stent was placed, bridging the hepatic parenchyma. MR venogram confirmed placement. RESULTS: Successful portal vein puncture was achieved in all animals. The number of punctures required decreased from 12 in the first animal to a single puncture in the last eight swine. A stent was successfully placed across the hepatic tract in all six swine. CONCLUSIONS: Real-time MR imaging proved to be a feasible method to guide portal vein puncture and TIPS placement in pigs.

Pelvic arterial embolization for control of obstetric hemorrhage: a five-year experience.

OBJECTIVE: Obstetric hemorrhage is a significant cause of maternal morbidity and death. Postpartum hemorrhage that cannot be controlled by local measures has traditionally been managed by bilateral uterine artery or hypogastric artery ligation. These techniques have a high failure rate, often resulting in hysterectomy. In contrast, endovascular embolization techniques have a success rate of >90%. An additional benefit of the latter procedure is that fertility is maintained. We report our experience at Stanford University Medical Center in which this technique was used in 6 cases within the past 5 years. STUDY DESIGN: Six women between the ages of 18 and 41 years underwent placement of arterial catheters for emergency (n = 3) or prophylactic (n = 3) control of postpartum bleeding. Specific diagnoses included cervical pregnancy (n = 1), uterine atony (n = 3), and placenta previa and accreta (n = 2). RESULTS: Control of severe or anticipated postpartum hemorrhage was obtained with transcatheter embolization in 4 patients. A fifth patient had balloon occlusion of the uterine artery performed prophylactically, but embolization was not necessary. In a sixth case, bleeding could not be controlled in time, and hysterectomy was performed. The only complication observed with this technique was postpartum fever in 1 patient, which was treated with antibiotics and resolved within 7 days. CONCLUSIONS: Uterine artery embolization is a superior first-line alternative to surgery for control of obstetric hemorrhage. Use of transcatheter occlusion balloons before embolization allows timely control of bleeding and permits complete embolization of the uterine arteries and hemostasis. Given the improved ultrasonography techniques, diagnosis of some potential high-risk conditions for postpartum hemorrhage, such as placenta previa or accreta, can be made prenatally. The patient can then be prepared with prophylactic placement of arterial catheters, and rapid occlusion of these vessels can be achieved if necessary.

Percutaneous balloon fenestration and stenting for life-threatening ischemic complications in patients with acute aortic dissection.

OBJECTIVES: Acute aortic dissection frequently causes life-threatening ischemia of end-organs, historically associated with mortality exceeding 60%. Reperfusion with the use of interventional radiologic methods has evolved as a promising treatment. We report results of our initial 6 years of experience with percutaneous balloon fenestration of the intimal flap and endovascular stenting. METHODS: Forty patients (32 male and 8 female) with a median age of 53 years (range 16-86 years) underwent percutaneous treatment for peripheral ischemic complications of 10 type A and 30 type B acute aortic dissections since 1991. Twenty patients had ischemia of multiple organ systems. Thirty patients had renal, 22 had leg, 18 had mesenteric, and 1 had arm ischemia. RESULTS: Fourteen patients were treated with stenting of either the true or false lumen combined with balloon fenestration of the intimal flap, 24 with stenting alone, and 2 with fenestration alone. Successful revascularization was achieved in 93% +/- 4% (+/-70% confidence levels) of patients (37/40). Nine patients had procedure-related complications. The 30-day mortality rate was 25% +/- 7% (10/40), often related to irreversible ischemia of intra-abdominal organs that was present before the procedure. Of the remaining 30 patients, 5 have died and the remaining 25 continue to have relief of ischemic symptoms at a mean follow-up of 29 months. CONCLUSION: Percutaneous balloon fenestration of the intimal flap and endovascular stenting is an effective treatment for life-threatening ischemic complications of acute aortic dissection.

Endovascular stent-graft placement for the treatment of acute aortic dissection.

BACKGROUND: The standard treatment for acute aortic dissection is either surgical or medical therapy, depending on the morphologic features of the lesion and any associated complications. Irrespective of the form of treatment, the associated mortality and morbidity are considerable. METHODS: We studied the placement of endovascular stent-grafts across the primary entry tear for the management of acute aortic dissection originating in the descending thoracic aorta. We evaluated the feasibility, safety, and effectiveness of transluminal stent-graft placement over the entry tear in 4 patients with acute type A aortic dissections (which involve the ascending aorta) and 15 patients with acute type B aortic dissections (which are confined to the descending aorta). Dissections involved aortic branches in 14 of the 19 patients (74 percent), and symptomatic compromise of multiple branch vessels was observed in 7 patients (37 percent). The stent-grafts were made of self-expanding stainless-steel covered with woven polyester or polytetrafluoroethylene material. RESULTS: Placement of endovascular stent-grafts across the primary entry tears was technically successful in all 19 patients. Complete thrombosis of the thoracic aortic false lumen was achieved in 15 patients (79 percent), and partial thrombosis was achieved in 4 (21 percent). Revascularization of ischemic branch vessels, with subsequent relief of corresponding symptoms, occurred in 76 percent of the obstructed branches. Three of the 19 patients died within 30 days, for an early mortality rate of 16 percent (95 percent confidence interval, 0 to 32 percent). There were no deaths and no instances of aneurysm or aortic rupture during the subsequent average follow-up period of 13 months. CONCLUSIONS: These initial results suggest that stent-graft coverage of the primary entry tear may be a promising new treatment for selected patients with acute aortic dissection. This technique requires further evaluation, however, to assess its therapeutic potential fully.