Endovascular repair of thoracic aortic aneurysms: a paradigm shift in standard of care

The standard open surgical treatment of thoracic aortic aneurysms is associated with significant morbidity and mortality. Endovascular repair is less invasive and potentially less morbid for patients with multiple risk factors. The authors report their results in 9 consecutive high-risk patients treated with endovascular grafts from January 1998 through June 2000. There were 7 men and 2 women patients with an average age of 75 years. Mean aneurysm diameter was 7.1 cm. All aneurysms were repaired with Gianturco Z-stent polytetrafluoroethylene prostheses. There were no perioperative deaths. Mean length of stay was 6.3 days. Technical success was achieved in all 9 patients. Two patients had neurologic complications following repair (1 patient with transient lower extremity numbness related to spinal arthritis and 1 patient with bowel and bladder incontinence). Both patients were independent with ambulation. Mean follow-up was 15.8 months. There was no evidence of endoleak or stent migration during the follow-up period. These findings support endovascular treatment of high-risk patients with thoracic aneurysm.

Remote superficial femoral artery endarterectomy: Multicenter medium-term results

OBJECTIVE

The results of percutaneous transluminal angioplasty, atherectomy, and laser angioplasty for the treatment of long-segment (>10 cm) superficial femoral artery (SFA) occlusive disease have proved disappointing. Remote superficial femoral artery endarterectomy (RSFAE) is a minimally invasive procedure, performed through a single limited groin incision that may offer patency rates comparable with those of above-knee femoropopliteal (AKFP) bypass graft. In this retrospective multicenter study the medium-term results of RSFAE are examined.

METHODS

Sixty patients were included in this study. Indications for the procedure were claudication in 52 patients and limb salvage in eight patients. RSFAE was performed with the MollRing Cutter device through a femoral arteriotomy. The distal "flap" of atheroma was anchored by balloon/stent angioplasty through the femoral arteriotomy. All patients underwent a follow-up examination with serial color flow ultrasound scanning.

RESULTS

Ten patients with heavily calcified SFAs failed as "intentions to treat"; these patients underwent AKFP bypass grafting. The mean length of the endarterectomized SFAs was 22.3 cm (range, 8-37 cm). The primary cumulative patency rate by means of life-table analysis was 61.4% +/- 9% (SE), (mean, 12.9 months; range, 3-36 months). During follow-up, percutaneous transluminal angioplasty was necessary in 14 patients, for a primary-assisted patency rate of 82.6% +/- 8%. The locations of the restenoses after RSFAE were evenly distributed along the endarterectomized SFAs. There were no deaths and one wound complication (hematoma), and the mean hospital length of stay was 1.4 days +/- 0.8 days.

CONCLUSIONS

RSFAE is a safe and moderately durable procedure. If long-term patency rates are similar to those of AKFP bypass graft, RSFAE may prove to be a minimally invasive adjunct for the treatment of SFA occlusive disease that will lower operative morbidity, reduce hospital LOS, and shorten recuperation.

Repair of mycotic paravisceral aneurysm with a fenestrated stent-graft

PURPOSE

To report the successful endovascular repair of a mycotic paravisceral aneurysm using a fenestrated stent-graft.

METHODS AND RESULTS

A 55-year-old white female with a history of rheumatoid arthritis presented with an 8-cm paravisceral aneurysm secondary to pneumonia complicated by empyema. Intravascular ultrasound identified a defect in the aortic wall at the level of the celiac axis. Repair was accomplished with a fenestrated stent-graft that excluded the aneurysm and maintained flow to the celiac axis and superior mesenteric artery. Recovery was uneventful and the patient was discharged in 2 days. Six-month follow-up computed tomographic scanning confirmed aneurysm exclusion and flow to the celiac and superior mesenteric arteries. There was no evidence of graft infection. The patient died from a clinically diagnosed myocardial infarction 10 months after the stent-graft repair.

CONCLUSIONS

Fenestrated stent-graft repair may evolve into a useful technique for the treatment of mycotic paravisceral aneurysms.

Minimally invasive aortic surgery: endovascular stent-graft repair of abdominal aortic aneurysm

Minimally invasive surgical therapies are popular with patients and third party payors because they offer increased safety, decreased pain, as well as shorter recovery times and hospital stays when compared to standard open surgery. Minimally invasive aortic surgery is now a practical reality. Our experience with 150 endovascular stent-graft aortic aneurysm repairs at Baptist Hospital East is detailed in the following report. In our practice, stent-grafting is now the treatment of choice for infrarenal abdominal aortic aneurysms within the context of clinical trials.

Prevention of spinal cord ischemia in an ovine model of abdominal aortic aneurysm treated with a self-expanding stent-graft

PURPOSE

To present novel techniques to prevent spinal ischemia during aneurysm creation and chronic bifurcated stent-graft implantation in an ovine model of abdominal aortic aneurysm (AAA).

METHOD

Experimental AAAs were created in 38 sheep. To prevent spinal ischemia, an internal aortic shunt was used during aneurysm creation. In the animals designated to receive bifurcated stent-grafts, a left external iliac-to-internal iliac bypass was performed to revascularize the caudal artery and prevent postdeployment spinal cord ischemia. Specimens were harvested at 1 week, 1, 3, and 6 months, and 1 year.

RESULTS

Aneurysms were successfully created without paralysis in 35 animals. Two died due to aspiration pneumonia. Of the 33 animals implanted with endografts, 16 (94%) of 17 with straight devices and 15 (94%) of 16 with bifurcated stent-grafts survived with well-functioning, patent stent-grafts. Paralysis developed in 2 animals after endografting due to technical failures.

CONCLUSIONS

The use of an internal shunt during aneurysm creation and internal iliac-to-external iliac transposition prior to bifurcated stent-graft deployment prevented spinal ischemia in an ovine AAA model. Chronically deployed stent-grafts were well tolerated.

Phlegmasia complicating prophylactic percutaneous inferior vena caval interruption: a word of caution

PURPOSE

The purpose of this study was to evaluate the incidence of thrombotic complications in patients with deep vein thrombosis (DVT) who were treated with percutaneous inferior vena caval interruption in place of anticoagulation.

METHODS

A retrospective review of all percutaneously placed inferior vena cava filters for 1 year, August 1993 through July 1994, was performed.

RESULTS

Thirty-three percutaneous inferior vena cava filters were placed in 32 patients. The underlying disease was pulmonary embolism in 15 (47%) and DVT in 17 (53%) patients. Of patients with pulmonary embolism, 11 had a documented DVT, and four were not evaluated for DVT. There were 14 men and 18 women, with a mean age of 63.5 years (range 24 to 93 years). Indications for vena caval interruption were recurrent pulmonary embolism with therapeutic anticoagulation (n = 2 [6%]), prophylactic insertion with documented pulmonary embolism and therapeutic anticoagulation (n = 8 [25%]), documented pulmonary embolism and absolute contraindication to anticoagulation (n = 5 [16%]), documented DVT and absolute contraindication to anticoagulation (n = 2 [6%]), prophylactic insertion with documented DVT and therapeutic anticoagulation (n = 5 [16%]), and documented DVT with relative contraindication to anticoagulation (n = 10 [31%]). Of the 32 patients with inferior vena cava filters, 17 were not given anticoagulants (7 absolute contraindications, 10 relative contraindications), and 15 were given anticoagulants. Insertion of a percutaneous inferior vena cava filter in patients who were not given anticoagulants was followed by the development of phlegmasia cerulea dolens in four patients (24%), which was bilateral in two patients; one patient eventually died. No patients treated with inferior vena cava filter and anticoagulation had development of phlegmasia.

CONCLUSIONS

Percutaneous inferior vena caval interruption effectively prevents pulmonary embolism in patients with DVT but does not impact the underlying thrombotic process and in fact may contribute to progressive thrombosis in patients who are not given anticoagulants. Anticoagulation with intravenous heparin in safe and effective therapy for DVT in most patients. We believe that percutaneous insertion of vena cava filters should not replace anticoagulation in routine proximal DVT, and those patients who require an inferior vena cava filter for failure of anticoagulation should continue to receive heparin to treat the primary thrombotic process. We caution that relative contraindications to anticoagulation should be carefully scrutinized before recommending vena cava interruption as a primary therapy for DVT.

Treatment of bacteria-biofilm graft infection by in situ replacement in normal and immune-deficient states

PURPOSE

Complications of grafts infected with coagulase-negative staphylococci can be eradicated by antibiotic administration, tissue debridement, and in situ graft replacement, but successful treatment may be diminished in a setting of altered immune function.

METHODS

In a canine model of an established aortic graft infection from Staphylococcus epidermidis, outcomes after in situ replacement were compared between normal dogs and animals made immune-deficient by administration of azathioprine (50 mg/day) and prednisone (10 mg/day). In situ replacement of an infected infrarenal aortic graft with either antibiotic-bonded (silver-ciprofloxacin: Ag-cipro) or conventional polytetrafluoroethylene (PTFE) grafts was performed in 17 control and 18 immune-deficient animals.

RESULTS

Four weeks after implantation of a Dacron graft colonized with a biofilm of S. epidermidis, all study animals demonstrated a bacterial biofilm infection with perigraft inflammation or abscess, and in immune-suppressed dogs the incidence of perianastomotic aortitis was increased (p < 0.05). Six weeks after in situ replacement both the Ag-cipro and conventional PTFE grafts were healed without signs of infection in controls, but anatomic evidence of persistent infection and increased S. epidermidis recovery was observed in immune-suppressed animals that underwent in situ replacement of a standard (five of seven) versus antibiotic-bonded (one of 11) PTFE graft (p < 0.006). Overall in situ replacement with an antibiotic-bonded graft yielded a lower frequency of S. epidermidis recovery (two of 19 Ag-cipro graft biofilm with positive culture results versus nine of 16 conventional graft biofilm with positive culture results; (p < 0.003).

CONCLUSIONS

This study supports the efficacy of in situ replacement for low-grade graft infections caused by S. epidermidis in normal hosts and demonstrates superiority of antibiotic-bonded grafts in immune-deficient hosts.

The importance of intraoperative detection of residual flow abnormalities after carotid artery endarterectomy

PURPOSE

The efficacy of carotid endarterectomy in the prevention of strokes mandates low perioperative morbidity, as well as a low incidence of late ipsilateral stroke. This prospective study involving 430 patients (461 carotid endarterectomies) correlated the results of intraoperative assessment with end points of stroke and residual/recurrent internal carotid artery (ICA) stenosis.

METHODS

Adequacy of the repair was assessed by ultrasound studies (duplex scan and pulsed Doppler spectral analysis) alone (n = 142), ultrasound studies and arteriography (n = 268), or clinical inspection (n = 51). After operation, duplex ultrasonography was used to confirm patency and categorize severity of ICA stenosis. At operation 26 carotid endarterectomy sites (5.6%), were revised based on intraoperative studies.

RESULTS

Perioperative (30-day) morbidity rates were similar in patients with normal, mildly abnormal, or no ultrasound completion studies. There were six permanent (1.3%) and 12 temporary (2.6%) neurologic deficits and six deaths, including four fatal strokes and two fatal myocardial infarctions. By life-table analysis, the incidence of greater than 50% diameter-reducing ICA stenosis or occlusion was increased (p < 0.007, log-rank test) in patients with residual flow abnormality or no study. More important, patients with normal intraoperative flow studies had a significantly lower rate of late ipsilateral stroke compared with the remaining patient cohort (p = 0.04, log-rank test). During the mean 30-month follow-up interval, the incidence of late stroke was increased (p = 0.00016) in patients with ICA restenosis or occlusion (3/35) compared with patients without recurrent stenosis (3/426).

CONCLUSION

Confirmation of a normal repair at operation affords the best opportunity to minimize ischemic neurologic events and anatomic restenosis after carotid endarterectomy.

The role of duplex scanning versus angiography in predicting outcome after balloon angioplasty in the femoropopliteal artery

Duplex-derived velocity measurements were used to assess the hemodynamics of 64 femoropopliteal arterial sites in 59 patients after angiographically successful percutaneous transluminal balloon angioplasty. With use of angiography as the gold standard, percutaneous transluminal balloon angioplasty was judged to be successful if (1) evidence existed of a "split" caused by intimal dissection and splitting of atherosclerotic plaque; and (2) no significant diameter-reducing residual stenosis was observed at the percutaneous transluminal balloon angioplasty site. At 1 month, 55 limbs (86%) were hemodynamically and clinically improved by SVS/ISCVS clinical criteria for chronic limb ischemia. Of the 55 percutaneous transluminal balloon angioplasty sites, duplex scanning had identified 40 (63%) sites with a less than 50% diameter-reducing stenosis and 15 (27%) sites with a greater than 50% diameter-reducing stenosis within a week after percutaneous transluminal balloon angioplasty. Independent review of the 55 angiograms taken after percutaneous transluminal balloon angioplasty identified 39 sites (71%) with a split and 16 sites (29%) without. By life-table analysis, a greater than 50% diameter-reducing stenosis predicted a worse clinical outcome (15% at 1 year) compared with the presence of a less than 50% diameter-reducing stenosis (84% at 1 year) (p less than 0.001; log rank test). The presence or absence of an angiographic split was not a predictive factor of percutaneous transluminal balloon angioplasty outcome (split, 61% at 1 year; no split, 62% at 1 year) (p = 0.832; log rank test). The detection of a functional residual stenosis by duplex scanning did not correlate with angiographic appearance, but was predictive of clinical failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Monitoring functional patency of percutaneous transluminal angioplasty

Duplex scanning and Doppler-derived blood pressure measurements were used to serially monitor lower limb hemodynamics in 73 patients who underwent percutaneous transluminal angioplasty. Ninety percutaneous transluminal angioplasty sites judged technically satisfactory by arteriography were evaluated. Significant hemodynamic improvement was seen in 81 (90%) of the 90 limbs, although both hemodynamic and clinical improvement were achieved in only 77 (86%) limbs. Duplex scanning within 1 week of successful angioplasty identified moderate (20% to 49% diameter reduction) or severe (greater than 50% diameter reduction) residual stenosis in 49 (63%) of 77 balloon-dilated arterial segments. The presence of a greater than 50% diameter reduction residual stenosis predicted further restenosis and late clinical failure (11% success rate at 1 year). When the degree of residual stenosis at the percutaneous transluminal angioplasty site was less than 50% diameter reduction by duplex scanning, the procedure was durable (80% success rate at 2 years), even in patients with critical ischemia, poor runoff, or diabetes mellitus.

In situ replacement of vascular prostheses infected by bacterial biofilms

Late prosthetic graft infections are commonly the result of coagulase-negative staphylococci that survive within a biofilm on prosthetic surfaces and provoke perigraft inflammation. The indolent nature and microbiologic characteristics of bacterial biofilm infections coupled with the morbidity of graft excision and extraanatomic bypass grafting prompted us to use in situ graft replacement in 15 patients admitted to the hospital with 17 infected graft segments at a mean (+/- SEM) time interval of 70 +/- 16 months after graft implantation (n = 6) or revision (n = 9). Since 1986, 17 grafts (14 aortofemoral, 2 axillofemoral, and 1 femoropopliteal) infected by bacterial biofilms have been treated. Signs on admission included femoral pseudoaneurysm (n = 7), perigraft abscess (n = 6), or graft-cutaneous sinus tract (n = 4). No patient exhibited septicemia. At operation graft incorporation was absent and Gram's stain of perigraft exudate showed polymorphonuclear leukocytes but no bacteria. Culture of explanted graft material isolated coagulase-negative staphylococci (n = 12), Staphylococcus aureus (n = 1), and no growth (n = 2). All patients were successfully treated by a regimen that included parenteral antibiotics, removal of involved graft material, excision of inflamed perigraft tissue, and in situ replacement with an expanded polytetrafluoroethylene prosthesis. No deaths, graft thromboses, or deep wound infections occurred after operation. Recurrent graft infection did not develop during a follow-up interval that ranged from 5 to 50 months (mean, 21 months). Diagnosis of vascular prosthesis infection caused by bacterial biofilms can be based on signs at admission and operative findings. Complications of this perigraft infection can be eradicated by antibiotic administration, local debridement, and in situ graft replacement.

Antibiotic-bonded PTFE vascular grafts: the effect of silver antibiotic on bioactivity following implantation

Use of an infection-resistant vascular prosthesis has appeal for grafting in sites of potential contamination or to replace graft segments involved in low-grade infections caused by coagulase-negative staphylococci (CNS). In this study, antibiotic retention on polytetrafluoroethylene (PTFE) grafts prepared using three antibiotic-bonding methods was compared following implantation into the arterial circulation. Ciprofloxacin or silver-ciprofloxacin was bonded to PTFE surfaces by surfactant-mediated or direct bonding methods. Antibiotic-bonded grafts of each type (n = 8) or control grafts (n = 2) were used to replace the carotid or femoral arteries of 10 dogs. Duplicate grafts segments (0.5 x 0.5 cm) were explanted at various time intervals ranging from 1 hr to 14 days later and imprinted onto culture plates of Klebsiella pneumonia. Antibiotic retention (micrograms/ml) was determined by measuring zones of inhibition and correlated with known disc concentrations of ciprofloxacin. Antibacterial bioactivity of grafts bonded with silver-antibiotic complexes was superior (P less than 0.02) to bonding of antibiotic alone at 3 and 24 hr following implantation. Ciprofloxacin retention in excess of the minimum bactericidal concentration (0.5 microgram/ml) of Staphylococcus epidermidis was demonstrated on all silver-antibiotic-bonded grafts after 14 days of implantation. At 7 and 14 days following implantation, the bioactivity of all antibiotic-bonded grafts exceeded 0.125 micrograms/ml of ciprofloxacin, the minimum inhibitory concentration of S. epidermidis. Bonding of silver-ciprofloxacin on PTFE grafts provided an effective source of local antibiotic release at levels which may be useful for bypass grafting in contaminated wounds or for in situ replacement of grafts infected by CNS.