Chittur R. Mohan

Comparative efficacy and complications of vena caval filters

PURPOSE A variety of vena caval filters (VCFs) are available for usage. The choice of filter type depends on physician preference and certain patient variables. An evaluation of the different VCFs used in our institution was done to compare their efficacy and complication rates. METHODS The medical records of all patients who underwent insertion of a VCF from January 1987 to June 1993 at the University of Iowa Hospitals & Clinics and the affiliated Veterans Administration Medical Center were reviewed. One hundred ninety-nine VCFs were placed in 196 patients (123 males, 73 females), with a mean age of 61 years (range 13 to 87 years). Thirty-five (18%) VCFs (30 stainless steel Greenfield filters [SGFs] and five titanium Greenfield filters with modified hook [TGF-MHs]) were inserted in the operating room via an open technique. The remaining 164 VCFs (82%) were inserted in the radiology suite by a percutaneous technique (38 SGF, 23 TGF-MH, 51 Vena Tech filters [VTFs], 48 Birds nest filters [BNFs] and 4 Simon Nitinol filters). Thromboembolic risk factors in these 196 patients included malignancy (99), trauma (21), recent surgery (27), cerebrovascular accident with paralysis (6), and miscellaneous conditions (43). Indications for VCF placement included a contraindication to anticoagulation (92), complication of anticoagulation (44), failure of anticoagulation (26), prophylaxis (31), adjunct to pulmonary embolectomy (1), noncompliance (1), hemodynamically unstable patient (1), and prior VCF complication (3). Mean follow-up of the patients was 12 months (range 0 to 87 months). Because there were only four Simon Nitinol filters inserted during the study period, they were excluded from further analysis. RESULTS A comparative analysis revealed that there was a significantly higher incidence of symptomatic IVC thrombosis with the use of the BNF (n = 7) (14.6%) versus the SGF (n = 0) (0%), TGF-MH (n = 1) (3.6%), or VTF (n = 2) (4%) (p < 0.05 by chi-squared testing). The VCF-related mortality rate was also higher with the BNF (n = 5) (10.9%) versus the SGF (n = 1) (1.5%), TGF-MH (n = 1) (3.6%), or VTF (n = 0) (0%) (p < 0.05 by chi-squared testing). However there was no significant difference in the occurrence of clinically apparent recurrent pulmonary embolism during follow-up between the four different filter types (2 [4.2%] BNF, 3 [4.4%] SGF, 1 [3.6%] TGF-MH, and 1 [2%] VTF). CONCLUSION These data indicate that the use of the BNF was associated with increased morbidity and mortality rates compared with the use of the SGF, TGF-MH, and VTF filters.

The management of the infected aortic prosthesis: A current decade of experience

PURPOSE Newer approaches to the patient with an infected aortic graft are available. We reviewed a recent 10-year experience with a more traditional approach to evaluate its outcome in the 1990s. METHODS From January 1983 to January 1993, 27 patients with an aortic graft infection were treated at our institution. There were 18 paraprosthetic infections, eight graft enteric erosions, and one aortoduodenal fistula. The involved bypasses included 20 aortofemoral (74%), five aortoiliac (18%), and two aortic tube grafts (8%). Nineteen aortic replacements were done originally for aneurysmal disease (70%). We reviewed the outcome of each patient treated as it related to the method of management. The therapy for graft infection consisted of aortic graft removal and axillofemoral bypass in 20 patients (74%), treatment by an in situ method in four patients (15%), excision of an aortofemoral limb and extraanatomic bypass in two patients (7%), and extraanatomic bypass alone in one patient (4%). In the group treated by graft removal and extraanatomic bypass, four patients (20%) had staged operations (extraanatomic bypass followed by interval aortic graft removal), nine (45%) had single operations with extraanatomic bypass preceding graft removal, and seven (35%) had single operations with graft removal preceding extraanatomic bypass. RESULTS The 30-day operative mortality rate was 3.7%. There were no instances of aortic stump blowout. The 3-year primary patency rate for axillofemoral bypass limbs was 80.2%, and the secondary patency rate was 87.4%. No limbs were lost as a result of ischemic complications. There was one late amputation for an unrelated problem. CONCLUSIONS The results of alternate approaches to the management of patients with infected aortic grafts were equivalent both in terms of perioperative mortality and morbidity rates in this group of patients. Complete excision of the aortic graft with axillofemoral bypass provided a satisfactory long-term outcome and remains the standard with which other approaches must be compared.

Selection of patients for cardiac evaluation before peripheral vascular operations

PURPOSE This study evaluated the value of preoperative cardiac screening with dipyridamole thallium scintigraphy and radionuclide ventriculography in vascular surgery patients. METHODS From July 1, 1989, to Dec. 31, 1991, we routinely (irrespective of the patients cardiac history or symptomatology) performed dipyridamole thallium scintigraphy (DTS) and radionuclide ventriculography (RVG) in 394 patients being considered for an elective vascular operation. Patients with reversible defects on DTS underwent coronary arteriography. RESULTS DTS results were normal in 146 patients (37%), showed a fixed defect in 75 (19%), and showed a reversible defect in 173 (44%). Patients with and without a history of angina or myocardial infarction had identical rates of reversible defects. Normal left ventricular function (> 50%) was noted in 76% of the patients; 17% had moderate dysfunction (35% to 50%) and 7% had a low ejection fraction (< 35%). The finding of severe coronary artery disease led to cardiac revascularization in 17 patients who had no prior history of cardiac disease and in 13 patients with a history of angina or myocardial infarction. Two deaths and nine major complications were associated with coronary arteriography and cardiac revascularization. Vascular procedures (144 aortic, 53 carotid, 146 infrainguinal) were ultimately performed in 343 patients, with a mortality rate of 1.7% (3.5% aortic, 0% carotid, and 0.7% infrainguinal bypass). The nonfatal perioperative myocardial infarction rate was 2.0%. We monitored all 394 patients for cardiovascular events, with a mean follow-up of 40 months. Patients who underwent cardiac revascularization had a 4-year survival rate of 75%, which was similar to those with a normal DTS. Late cardiac events were significantly more frequent in patients who had either a reversible DTS or RVG < 35%. CONCLUSIONS Routine cardiac screening of vascular surgery patients had similar impact on patients irrespective of their prior history or current symptoms suggesting coronary artery disease. Routine screening did not result in substantial benefit. Screening studies such as DTS or RVG may be most useful as part of an overall risk versus benefit assessment in patients without active symptoms of coronary artery disease who have less compelling indications for vascular intervention (claudication, moderate-sized aortic aneurysms, or asymptomatic carotid disease).

A Comparative Evaluation of Femorofemoral Crossover Bypass and Iliofemoral Bypass for Unilateral Iliac Artery Occlusive Disease

The purpose of this study was to compare the results of extra-anatomic femorofemoral crossover bypass grafting to the anatomic iliofemoral bypass grafting procedure in the treatment of patients with unilateral iliac artery occlusive disease with respect to patency and limb salvage. The records of all patients with unilateral iliac artery disease who underwent revas cularization between January 1988 and December 1995 at the University of Iowa Hospitals and Clinics (UIHC) were retrospectively reviewed; 108 patients were identified and divided into two groups. Group I (n=68; male/female=44/24) was composed of all patients who underwent a femorofemoral crossover extra-anatomic bypass. All patients who underwent an iliofemoral anatomic bypass constituted group II (n=40; male/female=24/16). The mean age for group I was 60 years (range 28-87) and for group II, 54 years (range 14-86). The medical risk factors between both groups were comparable. Except for the higher incidence of gangrene in group II the indications for surgery were comparable between both groups. (continued on next page) A polytetrafluoroethylene graft was used in 88% of group I patients and in 90% of group II patients (NS). In the remaining patients, an autogenous vein conduit was used. Two patients from group I (2.9%) died in the perioperative period (NS). Graft patency was assessed by clinical evaluation, Doppler-derived ankle/brachial indices, and color duplex imaging. The cumulative primary and secondary patency rates, limb salvage, and patient survival were calculated by use of life table analysis (SE<0.1). The need for simultaneous outflow and inflow procedures at the time of surgery was comparable between both groups. The proportion of patients who underwent further revasculariza tion during follow-up was also comparable. The 5-year primary and secondary graft patency rates were 81.7% and 90.3%, in group I and 61.3% and 80.5% in group II. Although the difference between both groups was not significant there was a tendency toward higher rates with femorofemoral bypass. The 5-year survival rates of 80.3% for group I and 73.3% for group II were comparable. These data suggest that there is no significant difference in the long-term results between the femorofemoral crossover bypass grafts and iliofemoral grafts. Both procedures result in acceptable patency and limb salvage rates. The femorofemoral bypass is, however, more attractive, for it can be performed under local anesthesia if needed and does not involve the creation of the retroperitoneal incision necessary with the iliofemoral bypass.

Open Repair and Endovascular Covered Stent Placement in the Management of Bilateral Axillary Artery Aneurysms

A 72-year-old male with chronic obstructive pulmonary disease and hyperlipidemia presented with acute right upper limb ischemia. Arterial occlusion was found to be secondary to a thrombosed axillary artery aneurysm. An open repair was performed with a polytetrafluoroethylene (PTFE) graft. On further workup, the patient was found to have an asymptomatic axillary artery aneurysm on the left-hand side. Endovascular repair with a covered stent was chosen to treat this aneurysm.

Endovascular Repair of Carotid Artery Pseudoaneurysm After Carotid Endarterectomy With Self-Expanding Covered Stents—A Long-Term Follow-Up

A 66-year-old Caucasian man with type 2 diabetes mellitus, peptic ulcer disease, peripheral vascular disease, and a 70% symptomatic carotid stenosis underwent a successful carotid endarterectomy with intraoperative shunting and Dacron patch closure in October 2000. Three months later, he developed a pseudoaneurysm at the site of the surgical repair. This was successfully treated with endovascular covered stents and has continued to remain patent at 9-year follow-up. Carotid artery pseudoaneurysms are secondary to trauma, infection, or previous surgery. Open surgical repair has been the treatment of choice for these pseudoaneurysms. However, open repairs are difficult and carry a high morbidity. Thus, endovascular therapy is a valid treatment for carotid artery pseudoaneurysm. Reviewing the published data, this is the first case report with successful endovascular covered stent placement for a carotid pseudoaneurysm with 9-year follow-up.

The Aortic Polytetrafluoroethylene Graft: Further Experience

OBJECTIVES We analysed our results with the use of aortic polytetrafluoroethylene PTFE grafts over the last 7.5 years. A historical comparison was also made between the results with non-stretch PTFE (NS-PTFE) (1987-91) and stretch PTFE (S-PTFE) grafts (1991-94). MATERIALS 244 infrarenal aortic replacements or bypasses with PTFE grafts were performed at the University of Iowa Hospitals and Clinics from January 1987 to June 1994. Infrarenal aortic replacement was indicated for aortic aneurysmal disease in 192 patients (elective 151, symptomatic 20, ruptured 21) and bypass for aorto-iliac occlusive disease in 52 patients (disabling claudication 28, limb salvage 24). Patients ranged in age from 37 to 93 years (mean 68 years). There were 161 males and 83 females. Medical risk factors included hypertension (55%), coronary artery disease (31%), COPD (23%), diabetes mellitus (12%) chronic renal failure (9%), and smoking (61%). Aortic replacement or bypass was done with a NS-PTFE graft in 108 patients (44%) and a S-PTFE graft in 136 patients (56%). Postoperative ultrasound (US) scans and/or CT-studies were available in 40 patients with NS-PTFE and 26 patients with S-PTFE grafts. MAIN RESULTS The 30 day operative mortality was: elective AAA patients (1.3%), symptomatic AAA patients (10%), ruptured AAA patients (48%), limb salvage patients (4.1%) and disabling claudication patients (0%). Graft related complications included five graft limb thromboses (4 NS-PTFE, 1 S-PTFE). Two thromboses occurred perioperatively and the three others at 24, 28 and 30 months postoperatively. Two other graft related complications included a mixed pseudomonas and streptococcus groin infection with a culture negative perigraft fluid collection occurring 3 weeks following surgery (NS-PTFE), and distal aortic anastomotic suture line bleed on the first postoperative day following replacement of a ruptured AAA with a S-PTFE graft. Based on US and/or CT imaging studies, the mean internal diameters of the bodies of 40 NS-PTFE and 26 S-PTFE grafts were 11% and 10% greater than the manufacturers specified sizes at a mean follow-up duration of 36 and 10 months respectively. CONCLUSIONS These data reveal that a PTFE graft performs satisfactorily in the aortic position with minimal adverse clinical sequence over a 7.5 year period. Continued long term follow up data will determine the ultimate suitability of aortic PTFE grafts.

Celiac Artery Stent Placement for Coronary Ischemia

INTRODUCTION The use of endovascular technology for mesenteric interventions has become an increasingly accepted treatment modality. We present an unusual case of celiac artery stent placement for coronary ischemia. CASE DESCRIPTION A 66-year-old male with a history most notable for coronary artery disease and coronary artery bypass grafting (CABG) x 3 utilizing left internal mammary artery to left anterior descending, radial artery to first diagonal and his right gastroepiploic artery (GEA) to posterior descending artery presented with chest pain. His work-up included a cardiac catheterization that revealed a 90% stenosis at the origin of the celiac axis. A subsequent computerized tomography angiogram confirmed this and noted moderate stenosis of his superior mesenteric artery (SMA) as well as severe inferior mesenteric artery (IMA) stenosis. The patient was taken for mesenteric angiography by vascular surgery at which time he underwent balloon-expandable stent placement in the celiac axis. The patient tolerated this procedure well and was noted to have an improvement in his symptoms postoperatively. DISCUSSION Use of arterial conduits for CABG have proven to be superior to vein. Long-term viability of the GEA as a conduit is dependent in part on the patency of mesenteric circulation. Our findings demonstrate a viable endovascular treatment option for angina pectoris secondary to mesenteric stenosis in this unique patient population.

Aneurysms of the Brachiocephalic Arteries as a Source of Brain Embolization

The presence of atherosclerotic plaque at the carotid bifurcation is recognized as a frequent cause of transient ischemic attacks (TIAs) and strokes that involve the anterior cerebral circulation. More rarely, these symptoms may be due to atherosclerotic plaque in the common carotid arteries or the innominate artery. Usually the plaque is at the origin of these vessels. Similarly, in the posterior cerebral circulation, atherosclerotic disease of the vertebral arteries may be a source of TIAs and strokes. The symptoms of cerebral ischemia from extracranial arterial disease are thought to be related mainly to embolization rather than hypoperfusion unless the involved extracranial artery is thrombosed. Although atherosclerotic embolic disease of the aforementioned extracranial arteries is the major etiology of TIAs and strokes, cerebral embolization from a cardiac source accounts for a large number of such events. Another potential but rare source of cerebral embolization is from intraluminal thrombus present in an aneurysm of the brachiocephalic arteries. This latter problem forms the basis of this review.

Aneurysmal Changes in an in Situ Saphenous Vein Bypass A Case Report

The development of an aneurysm in an in situ bypass has not been reported to date in the major series of in situ bypasses. A review of the English literature did reveal one other report of an aneurysm developing following an in situ bypass. In this report, we describe a sixty-seven-year-old woman with a true aneurysm that developed in an in situ greater saphenous vein bypass six years after implantation.