Solitary iliac branch endoprosthesis placement for iliac artery aneurysms.

BACKGROUND: Isolated iliac artery aneurysms (IAAs), accounting for 2% to 7% of all abdominal aneurysms, are often treated with the use of iliac branched endografts. Although outside the manufacturer's instructions for use, iliac branched devices can be used solely, without the adjunctive placement of an endovascular aneurysm repair device, for the treatment of an isolated IAA. In the present study, we have described the outcomes of the use of the Gore iliac branched endoprosthesis (IBE; W.L. Gore & Associates, Flagstaff, Ariz), without the support of an infrarenal endovascular aneurysm repair device, for the exclusion of an isolated IAA. The present study was an international multicenter retrospective cohort analysis. METHODS: All the patients who had undergone treatment with a solitary IBE for IAA exclusion from January 11, 2013 to December 31, 2018 were retrospectively reviewed. The primary outcome was technical success. The secondary outcomes included mortality, intraoperative and postoperative complications, and reintervention. RESULTS: A total of 18 European and American centers participated, with a total of 51 patients in whom 54 IAAs were excluded. The technical success rate was 94.1%, with an assisted technical success rate of 96.1%. No 30-day mortality occurred, with 98.1% patency of the internal and external iliac artery found at 24 months of follow-up. At 24 months of follow-up, 81.5% of the patients were free of complications and 90% were free of a secondary intervention. CONCLUSIONS: Treatment with a solitary IBE is a safe and, at midterm, an effective treatment strategy for selected patients with a solitary IAA.

Noninvasive biomagnetic detection of intestinal slow wave dysrhythmias in chronic mesenteric ischemia.

Chronic mesenteric ischemia (CMI) is a challenging clinical problem that is difficult to diagnose noninvasively. Diagnosis early in the disease process would enable life-saving early surgical intervention. Previous studies established that superconducting quantum interference device (SQUID) magnetometers detect the slow wave changes in the magnetoenterogram (MENG) noninvasively following induction of mesenteric ischemia in animal models. The purpose of this study was to assess functional physiological changes in the intestinal slow wave MENG of patients with chronic mesenteric ischemia. Pre- and postoperative studies were conducted on CMI patients using MENG and intraoperative recordings using invasive serosal electromyograms (EMG). Our preoperative MENG recordings showed that patients with CMI exhibited a significant decrease in intestinal slow wave frequency from 8.9 ± 0.3 cpm preprandial to 7.4 ± 0.1 cpm postprandial (P < 0.01) that was not observed in postoperative recordings (9.3 ± 0.2 cpm preprandial and 9.4 ± 0.4 cpm postprandial, P = 0.86). Intraoperative recording detected multiple frequencies from the ischemic portion of jejunum before revascularization, whereas normal serosal intestinal slow wave frequencies were observed after revascularization. The preoperative MENG data also showed signals with multiple frequencies suggestive of uncoupling and intestinal ischemia similar to intraoperative serosal EMG. Our results showed that multichannel MENG can identify intestinal slow wave dysrhythmias in CMI patients.

Impact on physician workload and revenue following the creation of a specialty vein clinic within an academic vascular practice.

OBJECTIVE: To evaluate the impact of creating a new specialty vein clinic within an academic-based vascular practice on clinical volume, physician workload and financial parameters. METHODS: All patients evaluated and treated for varicose vein related problems within an academic vascular surgery practice were identified from institutional billing databases. Data were stratified according to the time period prior to establishing a vein clinic (PRE-VC) (1999-2001) and after creation of a vein clinic (POST-VC) (2002-2004). Clinical volume, physician workload and financial parameters were evaluated. Comparisons were made between vein (VEIN) and overall vascular (VASC) practice trends. RESULTS: Comparison of clinical volume, physician workload and financial parameters in both the clinic and operative settings showed larger and more rapid expansion of the VEIN practice than VASC practice between PRE-VC and POST-VC time periods (VEIN vs.VASC growth, respectively: new patient clinic volume +162 vs. +18%; clinic relative value units (RVUs) +131 vs. +1%, clinic revenue +201 vs. +44%; procedure volume +348 vs. +19%; procedure RVUs +129 vs. +11%; procedure revenue +93 vs. +10%). Comparing the beginning of PRE-VC to the end of POST-VC time periods, an increasing trend was also present for the percentage of VEIN practice accounting for the total VASC practice (%VEIN PRE-VC to POST-VC, respectively: new patient clinic volume 11.6-30.2%; clinic RVUs 3.2-48.2%; clinic revenue 17.6-31.2%; procedure volume 3.1-14.3%; procedure RVUs 2.8-9.8%; procedure revenue 3.3-11.7%). CONCLUSION: Establishing a specialty vein clinic within an academic vascular practice can lead to a rapid expansion of clinical volume with associated increase in physician workload and reimbursement at a rate greater than that for the overall vascular practice.

Impact of Medicare denials on noninvasive vascular diagnostic testing.

PURPOSE: The purpose of this study was to evaluate the impact of Medicare coverage limitations and claim denials on noninvasive vascular diagnostic testing. METHODS: All Medicare claims for noninvasive vascular diagnostic studies from January 1, 1999, to December 31, 1999, were identified from the hospital billing database according to Current Procedural Terminology codes for carotid artery duplex ultrasound scan, venous duplex ultrasound scan, and lower-extremity arterial Doppler scan. Reasons for Medicare denial of payment for these tests were reviewed and a cost analysis was performed. RESULTS: During the 1-year period, there were 1096 noninvasive vascular diagnostic studies performed on Medicare patients. Of these 1096 tests, 176 (16.1%) were denied by Medicare (19.6% of 408 carotid duplex ultrasound scans, 16.8% of 345 venous duplex ultrasound scans, and 11.1% of 343 lower-extremity arterial Doppler scans). Of the noninvasive vascular tests denied by Medicare, an abnormal result was present in 72.5% of carotid duplex ultrasound scans, 32.8% of venous duplex ultrasound scans, and 78.9% of lower-extremity arterial Doppler scans. Overall, 88.1% of all initially denied claims (N = 176) were ultimately reimbursed by Medicare after resubmission, including 77.1% of the 118 claims denied based on compliance rules for "medical necessity." CONCLUSION: Because of coverage limitations, Medicare denials of noninvasive vascular diagnostic tests can lead to potential uncompensated physician and hospital technical fees if denied claims are unrecognized. Vascular laboratories performing these tests need to review compliance with Medicare guidelines. Improvements may need to be made at both the provider and Medicare carrier levels in obtaining reimbursement for appropriately ordered noninvasive vascular diagnostic studies.

Durability of percutaneous angioplasty and stent implantation for the treatment of abdominal aortic coarctation: a case report.

Abdominal aortic coarctation (AAC) is an uncommon vascular lesion with serious sequelae related to uncontrolled hypertension. Balloon-expandable stents have recently been utilized in the treatment of AAC as an alternative to surgical intervention. A 17-year-old female presented with hypertension uncontrolled by beta blockade. She underwent angiography, which revealed an isolated supraceliac aortic coarctation without visceral or renal artery involvement. Balloon angioplasty with stent placement was performed. At 2-year follow-up, a restenosis was identified and was treated with repeat balloon-expandable stent placement. Implantation of balloon-expandable stents is a safe and technically feasible treatment modality for abdominal aortic coarctation not involving the renal and mesenteric arteries. However, it is currently unknown whether the long-term durability of this approach may limit its effectiveness when compared to traditional surgical interventions.

The reduction of the allogenic transfusion requirement in aortic surgery with a hemoglobin-based solution.

OBJECTIVE: Because of allogenic red blood cell (RBC) availability and infection problems, novel alternatives, including hemoglobin-based oxygen-carrying solutions (HBOC), are being explored to minimize the perioperative requirement of RBC transfusions. This study evaluated HBOC-201, a room-temperature stable, polymerized, bovine-HBOC, as a substitute for allogenic RBC transfusion in patients undergoing elective infrarenal aortic operations. METHODS: In a single blind, multicenter trial, 72 patients were prospectively randomized two-to-one to HBOC (n = 48) or allogenic RBC (n = 24) at the time of the first transfusion decision, either during or after elective infrarenal aortic reconstruction. Patients randomized to the HBOC group received 60 g of HBOC for the initial transfusion and had the option to receive three more doses (30 g each) within 96 hours. In this group, any further blood requirement was met with allogenic RBCs. Patients randomized to the allogenic RBC group received only standard RBC transfusions. The efficacy analysis was a means of assessing the ability of HBOC to eliminate the requirement for any allogenic RBC transfusions from the time of randomization through 28 days. Safety was evaluated by means of standard clinical trial methods. RESULTS: The two treatment groups were comparable for all baseline characteristics. Although all patients in the allogenic RBC group required at least one allogenic RBC transfusion, 13 of 48 patients (27%; 95% CI, 15% to 42%) in the HBOC group did not require any allogenic RBC transfusions. The only significant changes documented were a 15% increase in mean arterial pressure and a three-fold peak increase in serum urea nitrogen concentration after HBOC. The complications were similar in both groups, with no allergic reactions. There were two perioperative deaths (8%) in the allogenic RBC group and three perioperative deaths (6%) in the HBOC group (P = 1.0). CONCLUSION: HBOC significantly eliminated the need for any allogenic RBC transfusion in 27% of patients undergoing infrarenal aortic reconstruction, but did not reduce the median allogenic RBC requirement. HBOC transfusion was well tolerated and did not influence morbidity or mortality rates.

Bifurcated devices in the treatment of abdominal aortic aneurysms: limitations and advantages of a single-component bifurcated prosthesis.

Currently, prostheses for endovascular repair of abdominal aortic aneurysms are divided into 2 device categories. Endoprostheses based on the first approach arise from the concept that endovascular grafting should ideally mimic standard surgical repair of abdominal aortic aneurysms. The second category of devices developed from a design strategy that was a conceptual outgrowth of transcathete-based techniques in which an endovascular graft is constructed de novo within the abdominal aorta from modular components. Both grafts are dependent on the successful exclusion of blood flow from the aneurysm sac. Ongoing clinical trials of these 2 categories of devices have yet to be completed with long-term data, but it is apparent even at this early stage that there exist both advantages and limitations to each system. In this review, these issues are discussed for single-component bifurcated endografts within the context of our 5-year experience gained through the use of a bifurcated device produced by Endovascular Technologies, Inc (EVT). Overall, present limitations of the single-component bifurcated prosthesis are related to graft size and the somewhat cumbersome maneuvers required for implantation. Nonetheless, the inherent advantages of these prostheses, including their durability and capacity to respond to aneurysm remodeling without late device failure, may ultimately provide the patient with a prosthesis with superior long-term clinical performance characteristics.

Duplex-directed vena caval filter placement: report of initial experience.

BACKGROUND: Fluoroscopy, cost, and patient transport contribute to difficulties occasionally associated with the placement of vena caval filters. Follow-up data in the literature document the use of duplex ultrasonography in visualizing the filter and determining caval patency. Filter placement at the bedside or in the vascular laboratory with duplex ultrasonography may simplify this common procedure. We have attempted to define the feasibility of this method. METHODS: Patients referred to the vascular surgery service for vena caval interruption were evaluated for ability to visualize the renal veins and inferior vena cava. Location of renal veins, maximum diameter of the vena cava, and presence or absence of thrombus were documented. If visualization was adequate, placement was performed at the bedside for patients in intensive care or in the vascular laboratory for nonmonitored patients. The initial 10 patients and subsequent patients in whom there was a question of adequate deployment underwent completion abdominal roentgenography. Patient follow-up was difficult. Duplex ultrasonography was used to assess migration, thrombus adherent to the filter, and vena caval patency. Patients in whom filter placement was prophylactic were given anticoagulants at the discretion of the primary physician. Inadequate visualization or vena caval size greater than 28 mm prompted fluoroscopic placement of the vena caval filter, because only Greenfield titanium filters were used in the study. RESULTS: Twenty-nine patients were referred for vena caval interruption. Inadequate visualization occurred in four obese patients, and filters were placed by fluoroscopy. There were no vena caval measurements greater than 24 mm. Twenty-five filters were placed without technical difficulty. One filter tilted into the right renal vein, requiring a suprarenal filter placed by fluoroscopy. Patient retrieval for follow-up has been difficult, but by ultrasonography there has been one vena caval thrombosis and no major filter migration. There have been no reported pulmonary emboli other than the one patient with initial tilt of the filter. CONCLUSIONS: Placement of vena caval filters is feasible with duplex ultrasonography. Visualization is the only limiting condition to placement and occurs rarely. Reducing the need for fluoroscopy, lowering costs, and not needing to transport the critically ill patient support the use of this system. Intravascular ultrasonography in selected patients may eliminate the need for fluoroscopic placement of vena caval filters.

Aortoiliac occlusive disease and gastrointestinal malignancy: changing therapeutic options.

Treatment of gastrointestinal malignancy encountered unexpectedly during procedures involving the abdominal aorta continues to be debated. Previously, simultaneous vascular procedures with intra-abdominal malignancy were rare. Most underwent vascular reconstruction followed by a delayed aortic procedure. With recent improvement in axillobifemoral graft patency, a one-stage procedure for aortoiliac disease should be entertained. We recently encountered a small bowel lymphoma while beginning an aortic replacement for aortic occlusion. Resection of a near-obstructing small bowel tumor immediately after axillofemoral reconstruction provided treatment of both entities at one time. Since the early description of axillofemoral bypass in 1963, varying success with extra-anatomic bypass has been reported. Early data for axillofemoral bypass were dismal, but with recent technical and graft improvements patency has been improved. Occult malignancy during aortic procedures is uncommon, about 2 to 4 per cent, but when met is usually dealt with after the patient recovers from the vascular procedure. With improvements in extra-anatomic bypass results, a single operative period can be entertained.

Vertebral artery surgery.

Vertebral artery revascularization is indicated for symptomatic vertebral artery disease. Safe and effective revascularization can be offered to such patients with good long-term outcomes. Percutaneous transluminal angioplasty, with and without stents, may eventually develop a role. However, prospective trials to compare angioplasty with the safety and long-term efficacy of surgical revascularization are needed before any benefit can be assumed.

Technical complications of endovascular abdominal aortic aneurysm repair.

PURPOSE: Results from 34 endovascular repairs of abdominal aortic aneurysms are reviewed to identify technical complications and relate them to anatomic and technical features of the operation. METHODS: Twenty-one patients underwent attempted tube graft repair (mean follow-up, 13 months). Thirteen patients underwent placement of a bifurcated graft (mean follow-up, 7.2 months). RESULTS: Twenty-five patients (74%) underwent repair without technical complication (16 tube graft and nine bifurcated graft). Of five patients who had tube graft complications, two involved small iliac arteries and resulted in arterial injury. One of these patients needed a femorofemoral bypass procedure, and the other required conversion to standard operation. Two patients had distal leaks associated with the attachment system, and one patient had misplacement of the distal attachment system. The two patients who had leaks were followed-up; one required operation after 7 months, whereas the other leak sealed. The patient who had distal attachment system misplacement had a second endograft placed within the first to provide a distal seal. The four patients who had bifurcated graft complications involved two graft limb stenoses, one managed with a Palmaz stent and the other with balloon angioplasty. The patient treated with balloon angioplasty had graft thrombosis 1 week after the operation, which resulted in the need for a femorofemoral bypass procedure. Another bifurcated graft patient had a graft limb twist, which has resulted in chronic claudication. One patient had placement of a limb too proximal in the common iliac artery with chronic leak, and an open operation was performed 18 months later. CONCLUSIONS: Technical complications in this series seem to be associated with short distal necks, small iliac arteries, tortuous iliac arteries, and atherosclerosis at the aortic bifurcation. We believe that experience and understanding of these issues will reduce the risk of these complications in the future.

Severe intraoperative coagulopathy following routine aortobi-iliac bypass with knitted Dacron graft.

Coagulopathy associated with aortic operation is generally described in patients undergoing supraceliac aortic clamping or ruptured abdominal aortic aneurysm repair. This intraoperative complication is managed with component blood replacement and occasional use of aminocaproic acid. The presence of intraoperative coagulopathy associated with aortic reconstruction for occlusive disease is not described. We report a case of severe intraoperative coagulopathy associated with aortobi-iliac artery bypass with a knitted Dacron prosthesis. Management of this complication was accomplished with administration of blood components, aminocaproic acid and explant of the Dacron prosthesis with polytetrafluoroethylene graft placement. The possibility of fibrinolysis induced by the knitted Dacron prosthesis is suggested.

Limb ischemia: surgical therapy in acute arterial occlusion.

Mortality and amputation rates from acute arterial occlusion are reported from 7 to 37 per cent and 10 to 30 per cent, respectively. Recent data from thrombolysis or peripheral arterial surgery suggest no significant differences between initial management with surgical or thrombolytic therapy. Mortality and amputation rates were in the above ranges. The last 230 procedures (216 patients) over 10 years were reviewed. All graft occlusions, cardiac catheterization injuries, and aortic balloon-related thromboses were excluded. Immediate and delayed amputation rates were 6.5 and 0.9 per cent. Death occurred in 21 patients (9.7%), with only 6 deaths over the last 6 years (3.8%). Except for transesophageal echocardiography, perioperative studies were of limited value. Long-term anticoagulation was also not effective in preventing recurrent episodes. A mortality rate of 9.7 per cent and amputation rate of 7.4 per cent justifies an early aggressive surgical approach. Limited perioperative studies and less prolonged anticoagulation may also improve cost containment.

Endovascular grafting of abdominal aortic aneurysms. A preliminary study.

OBJECTIVE: The authors report the experience of a single investigational center involving two Phase I and a Phase II clinical trials approved by the Food and Drug Administration (FDA) for the transfemoral implantation of woven Dacron grafts for abdominal aortic aneurysms. SUMMARY BACKGROUND DATA: In 1993, EndoVascular Technologies, Inc. ([EVT]; Menlo Park, CA), began an FDA-approved clinical trial of repair of abdominal aortic aneurysms by transfemoral placement of a tube endograft. Subsequently, a bifurcated endograft trial was started. This the first single institution report using the EVT endograft for both tube and bifurcated aortic replacement. METHODS: Seventeen patients were enrolled in two Phase I and one Phase II clinical trials. The Phase I tube graft trial and the Phase I bifurcated graft trial were nonrandomized studies. The Phase II tube graft trial consisted of a randomized prospective control trial of open endoaneurysmorrhaphy versus transfemoral placement of an endograft. RESULTS: Seventeen patients were enrolled in the trial. The graft was placed successfully in all but one patient. Five patients randomized to open procedure and one declined to participate. Eleven patients with endografts are available for follow-up. One graft has been explanted for attachment system migration. One patient is a late failure because of persistent filling of the aneurysm sac. CONCLUSION: Transfemoral placement of an endovascular graft is a viable and effective treatment of abdominal aortic aneurysms in the short term. Use of a bifurcated endograft will open the procedure to more patients. The ideal attachment system and graft material await long-term implantation follow-up.

Risk of spinal cord dysfunction in patients undergoing thoracoabdominal aortic replacement.

The records of 150 consecutive patients undergoing thoracoabdominal aortic replacement from 1980 to 1991 were retrospectively reviewed. There were 89 men and 61 women; mean age was 67.8 years (range: 33 to 88 years). Since June 1989, a multimodality prospective perioperative protocol was used to reduce the risk of spinal cord dysfunction. Ischemia is minimized by complete intercostal reimplantation whenever possible, cerebrospinal fluid drainage, and maintenance of proximal hypertension during cross-clamping. Spinal cord metabolism is reduced by moderate hypothermia, high-dose barbiturates, and avoidance of hyperglycemia. Reperfusion injury is minimized by the use of mannitol, steroids, and calcium channel blockers. Ninety-seven percent of patients survived long enough for evaluation of their neurologic function. Spinal cord dysfunction was reduced from 6 of 108 (6%) in the preprotocol group to 0 of 42 in the protocol group (0%) (p less than 0.01). The overall 30-day operative mortality was not significantly different between the groups (9% versus 12%, p = NS). A multimodality protocol appears to be effective in reducing the risk of spinal cord injury during thoracoabdominal aortic replacement.

Protecting the ischemic spinal cord during aortic clamping. The influence of anesthetics and hypothermia.

Infrarenal circumaortic occlusion devices were operatively placed in 74 New Zealand white rabbits. Two days after operation the animals were randomly assigned to one of seven treatment groups: I, control, n = 23; II, halothane, n = 8; III, thiopental, n = 12; IV, ketamine (30 mg/kg intravenously), n = 6; V, halothane+hypothermia, n = 8; VI, thiopental+hypothermia, n = 12; VII, ketamine+hypothermia, n = 5. In each group, the infrarenal aorta was occluded for 21 minutes. Final neurologic recovery after restitution of blood flow was graded as acute paraplegia, delayed paraplegia (neurologic deficit developing after initial recovery), or normal. Halothane alone was of no benefit. Hypothermia with any anesthetic was completely protective and reduced neurologic deficits to 0% compared with 91% in controls (p less than 0.05). Thiopental and ketamine treatment each reduced acute paraplegia to 17% (as compared with 61% in controls) and increased delayed paraplegia from 30% in controls to 75% and 50%, respectively (p less than 0.05 for thiopental, p = 0.10 for ketamine). The authors interpret the increase in delayed deficits and decrease in acute deficits as being the result of partial spinal cord protection. These findings document that this model of spinal cord ischemia is sufficiently sensitive to identify interventional treatments that protect the ischemic spinal cord.

Alpha-adrenergic blockade makes minimal contribution to ketanserin's hypotensive effect.

Ketanserin is a selective (S2) serotonin receptor antagonist currently under investigation as an antihypertensive. It has been suggested that the antihypertensive action of ketanserin might be principally due to alpha-adrenergic receptor antagonism rather than its effect on serotonin receptors. We therefore determined the contribution of alpha-adrenergic blockade to the hypotensive effects of ketanserin in six patients with hypertension and compared that with the alpha-adrenergic blockade produced by prazosin, a known alpha 1-adrenergic antagonist. Each patient received placebo, ketanserin (40 mg every 8 hours), and prazosin (5 mg every 8 hours). Each agent was administered for 4 weeks in random order. Both ketanserin and prazosin lowered blood pressure significantly and to a similar extent. The extent of alpha-adrenergic blockade was determined from the ability to inhibit the hypertensive effect of phenylephrine infusions. The dose of phenylephrine required to raise the blood pressure by 20 mm Hg was significantly higher during both ketanserin (1.41 +/- 0.27 micrograms/kg/min; p less than 0.05) and prazosin (4.99 +/- 0.77 micrograms/kg/min; p less than 0.01) administration compared with placebo (0.85 +/- 0.15 micrograms/kg/min). However, the dose ratio was more than fourfold higher during prazosin treatment (7.38 +/- 1.99; p less than 0.05) than during ketanserin (1.69 +/- 0.21). Thus at equipotent hypotensive doses the extent of alpha-blockade produced by ketanserin was more than fourfold lower than that of prazosin, implying that mechanisms other than alpha-blockade must contribute to the antihypertensive actions of ketanserin.