Charles P. Semba

Transluminal Placement of Endovascular Stent-Grafts for the Treatment of Descending Thoracic Aortic Aneurysms

BACKGROUND The usual treatment for thoracic aortic aneurysms is surgical replacement with a prosthetic graft, but the associated morbidity and mortality are considerable. We studied the use of transluminally placed endovascular stent-graft devices as an alternative to surgical repair. METHODS We evaluated the feasibility, safety, and effectiveness of transluminally placed stent-graft to treat descending thoracic aortic aneurysms in 13 patients over a 24-month period. Atherosclerotic, anastomotic, and post-traumatic true or false aneurysms and aortic dissections were treated. The mean diameter of the aneurysms was 6.1 cm (range, 5 to 8). The endovascular stent-grafts were custom-designed for each patient and were constructed of self-expanding stainless-steel stents covered with woven Dacron grafts. RESULTS Endovascular placement of the stent-graft prosthesis was successful in all patients. There was complete thrombosis of the thoracic aortic aneurysm surrounding the stent-graft in 12 patients, and partial thrombosis in 1. Two patients initially had small, residual patent proximal tracts into the aneurysm sac, but both tracts thrombosed within two months after the procedure. In four patients, two prostheses were required to bridge the aneurysm adequately. There have been no deaths or instances of paraplegia, stroke, distal embolization, or infection during an average follow-up of 11.6 months. One patient with an extensive chronic aortic dissection required open surgical graft replacement four months later because of progressive dilatation of the arch. CONCLUSIONS These preliminary results demonstrate that endovascular stent-graft repair is safe in highly selected patients with descending thoracic aortic aneurysms. This new method of treatment will, however, require careful long-term evaluation.

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.

Endovascular stent–graft repair of thoracic aortic aneurysms

UNLABELLED Conventional repair of aneurysms of the descending thoracic aorta entails thoracotomy and graft interposition. For elderly patients and those with previous operations, obesity, respiratory insufficiency, or other comorbidities, such a procedure entails significant mortality and morbidity. Transluminal stent-graft placement offers an alternative approach with potentially less morbidity and quicker recovery; however, the effectiveness and durability of stent-grafts remain uncertain. METHODS Since July 1992, thoracic aortic stent-grafts have been placed in 44 patients with a variety of pathologic conditions. Each graft was individually constructed from self- expanding, stainless-steel Z stents covered with a woven Dacron polyester fabric graft. Craft dimensions were determined from spiral computed tomographic scans. All implants were performed in the operating theater under fluoroscopic and transesophageal echocardiographic guidance. Follow-up was by computed tomography and contrast angiography in all cases. PATIENT DATA There were 36 men and 8 women. Mean age was 66 years (range 35 to 88 years). Mean aneurysmal diameter was 6.3 cm (range 4.0 to 9.4 cm). Etiologies included 23 degenerative aneurysms, four posttraumatic aneurysms, four pseudoaneurysms, and one chronic aortic dissection. RESULTS There were three early deaths (<30 days) and two late deaths. One early death resulted from graft failure. There were two instances of paraparesis or paraplegia, with one associated early death. A single stent was deployed in 27 patients, two stents were required in 14 patients, and three stents were required in three patients. In 23 patients, vascular access was attained through the femoral artery; abdominal aortic access, either native or graft, was necessary in the remaining 21 patients. Twelve grafts were placed in conjunction with open abdominal aortic surgical procedures. Mean follow-up (98% complete) was 12.6 months (range 1 to 34 months). One late death occurred from aneurysmal expansion and rupture in a patient with a persistent midgraft leak. The second late death may have resulted from aneurysmal rupture. Immediate thrombosis was achieved in 36 patients, and late thrombosis was achieved in three others. Failure to achieve complete aneurysmal thrombosis occurred in five patients, however, and one individual (previously noted) died of aneurysmal expansion and rupture; the remaining four are being carefully monitored. Only one patient has required conversion of the stent to an open procedure; a contained rupture of the false lumen of a chronic dissection eventually necessitated total descending thoracic aortic exclusion. CONCLUSIONS These early results support the hypothesis that endovascular stent-graft placement may be a safe and durable treatment for selected patients with aneurysmal disease of the descending thoracic aorta. Large introducer size (26F outer diameter) and relatively limited angulation capability, as well as imprecise deployment techniques, currently limit its applicability. Distal embolization and stent migration have not been observed. Failure to achieve complete aneurysmal thrombosis may allow continued aneurysmal expansion and rupture. Further follow-up is clearly necessary to evaluate the true long-term effectiveness of this procedure.

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.

Acute rupture of the descending thoracic aorta: repair with use of endovascular stent-grafts.

PURPOSE To describe the use of endovascular stent-grafts to treat acute ruptures of the descending thoracic aorta as an alternative to surgery in high-risk patients. MATERIALS AND METHODS From July 1992 to August 1996, 95 patients underwent stent-grafting of the descending thoracic aorta for a variety of lesions. Of these, 11 patients with acute (< or = 7 days) rupture from aneurysms (n = 8) or trauma (n = 3) underwent repair with use of endovascular stent-grafts. Rupture was confirmed with preoperative imaging studies and occurred in the mediastinum (n = 9), the pleural space (n = 1), or the lung (n = 1). All patients were considered high surgical risk due to generalized cardiopulmonary disease and/or previous thoracotomies. Stent-grafts were constructed from Z stents covered with polyester fabric and delivered through a catheter under fluoroscopic control from a remote access site. RESULTS Stent-graft deployment was successful in all patients. There were no complications of perigraft leak, stent migration, paraplegia, or intraoperative death. Two patients died in the follow-up period: one of ventricular perforation during unrelated thoracic surgery for tumor resection (day 1) and one of cardiac arrest (day 28). All others are alive (mean follow-up, 15.1 months). CONCLUSION For acute rupture of the thoracic aorta, endovascular stent-graft repair is technically feasible and may be a therapeutic alternative to a surgical interposition graft in patients considered high risk for conventional thoracotomy. Long-term studies are necessary to determine the role of stent-grafts in preventing future aortic rupture.

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.

MYCOTIC ANEURYSMS OF THE THORACIC AORTA : REPAIR WITH USE OF ENDOVASCULAR STENT-GRAFTS

PURPOSE Standard therapy of mycotic aneurysms in the descending aorta consists of thoracotomy and in situ graft placement or extraanatomic bypass. The alternative use of endovascular stent-grafts was evaluated for management of infected aneurysms of the thoracic aorta. MATERIALS AND METHODS In a retrospective analysis during a 5-year period, 112 patients underwent stent-graft placement for thoracic aortic aneurysms. Three patients (mean age, 68.6; range, 64-70 years) had mycotic thoracic aneurysms. Stent-grafts were constructed from Z stents covered with polyester fabric and were delivered remotely through a catheter under fluoroscopic guidance. RESULTS Complete thrombosis of the mycotic aneurysms was achieved in all patients. One patient required a second separate stent-graft placement procedure because of migration of the initial device; the second patient underwent surgical repair of a ruptured mycotic abdominal aortic aneurysm followed immediately by stent-graft placement for a chronic mycotic thoracic aneurysm; a third patient underwent repair of two infected false aneurysms secondary to complete rupture of a surgical interposition graft. There were no complications of persistent bacteremia despite placement of the stent-graft device at the site of primary infection, reinfection, delayed rupture, paraplegia, distal emboli, or surgical conversion. One patient died of cardiac arrest at 25 months; there were no perioperative deaths (< or = 30 days). The remaining two patients were alive and well at median follow-up of 24 months (range, 4-25 months). CONCLUSION Endovascular stent-grafts combined with antibiotic therapy may be an alternative to conventional thoracotomy in managing mycotic aneurysms of the descending thoracic aorta.

Central Venous Catheters in Home Infusion Care: Outcomes Analysis in 50,470 Patients

PURPOSE Outpatient home infusion therapy is increasing; however, little data exist on the outcomes of patients receiving care. The purpose of this study was to document the natural history of central venous catheters (CVCs) used in home infusion care to determine the rate and type of catheter complications. MATERIALS AND METHODS Data from the Strategic HealthCare Programs National Database from April 1999 to September 2000 were analyzed. Primary study objectives were to identify (i) types of CVCs and principal diagnoses, (ii) type and rate of catheter complications, and (iii) outcomes in managing thrombotic catheter complications. Event rates were calculated per 1,000 catheter days; 50,470 patients representing 2.83 million catheter days met study criteria. RESULTS The rates of complications (per 1,000 catheter days) for the most common events were: catheter dysfunction (0.83 total; 0.6 nonthrombotic, 0.23 thrombotic), catheter site infections (0.26), and bloodstream infections (BSIs; 0.19). A total of 4,138 complication events were identified (event rate per 1,000 days: 1.5). The total rates of complications with each catheter type were: midline catheters (4.5), PICCs (2.0), nontunneled central catheters (1.1), tunneled catheters (1.0), and chest ports (0.52). Catheter dysfunction with loss of patency was the most common group of complications. Thrombotic occlusion was the principal cause of catheter dysfunction, occurring in 28% of patients in this group, typically within 7 days of catheter insertion. BSI was reported in 541 patients, generally more than 30 days after catheter insertion. Catheter thrombosis outcomes resulted in therapy interruption (43%), catheter replacement (29%), premature CVC removal (14%), unscheduled emergency room visits (9%), and/or hospitalizations (6%). CONCLUSION Catheter dysfunction is the most frequent complication of all CVCs in this population, almost twice that of infections. Outpatient home infusion catheter dysfunction results in delays to therapy, unscheduled hospitalizations, and need for device replacement.

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.

Safety and Efficacy of Alteplase for Restoring Function in Occluded Central Venous Catheters: Results of the Cardiovascular Thrombolytic to Open Occluded Lines Trial

PURPOSE To evaluate the safety and efficacy of alteplase (TPA) for restoring function to occluded central venous catheters (CVCs). PATIENTS AND METHODS The study design was a phase III, open-label, single-arm multicenter trial. Subjects with occluded, nondialysis CVCs were enrolled. All subjects received a 2-mg dose of TPA within the dysfunctional catheter lumen that was allowed to dwell for 30 to 120 minutes. Functionality was tested at 30 and 120 minutes. If the CVC remained obstructed at 120 minutes, a second 2-mg TPA dose was allowed to dwell for 30 to 120 minutes. The primary safety end point was the rate of intracranial hemorrhage (ICH) within 5 days of treatment, and serious adverse events were recorded up to 30 days. RESULTS Nine hundred ninety-five patients received treatment (female, 562; male, 433; mean age, 50.7 years; range, 2 to 91 years). CVCs treated were as follows: single (26%), double (39%), or triple (6%) lumen catheters or ports (29%). The primary end point was 0% ICH within 5 days. There were no cases of death, major bleeding episodes, or embolic events attributable to treatment. Flow was successfully restored in 52% and 78% of CVCs at 30 and 120 minutes after one dose, and 84% and 87% at 30 and 120 minutes after a second dose, respectively. Restoration of flow was 86%, 93%, 90%, and 79%, for single, double, and triple lumen catheters and ports, respectively. Estimated 30-day catheter patency was 74%. CONCLUSION A regimen of up to two 2-mg doses of TPA is safe and effective for the restoration of flow to occluded central venous catheters.