William J. Sharp

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.

Endovascular Management of Venous Thrombotic and Occlusive Diseases of the Lower Extremities

Acute complications of deep vein thrombosis (DVT) of the lower extremities include pulmonary embolism and venous ischemia. Delayed complications include a spectrum of debilitating symptoms referred to as postthrombotic syndrome (PST). Anticoagulation therapy is recognized as the mainstay of therapy in acute DVT. However, there are few data to suggest any major beneficial effect on PTS, which is thought to be mediated by valve damage and/or occlusive chronic thrombus and venous scarring. Endovascular catheter-directed thrombolysis techniques with pharmacologic thrombolytic agents, used alone or in combination with mechanical thrombectomy devices, have been proven highly effective in clearing acute DVT, which may allow the preservation of venous valve function and prevention of subsequent venous occlusive disease. Definitive management of underlying anatomic occlusive abnormalities can also be undertaken.

Long-Term Outcome following Stent Reconstruction of the Aortic Bifurcation and the Role of Geometric Determinants

We assessed the long-term patency of kissing stent reconstruction of the aortoiliac bifurcation and identified variables that may influence it. We retrospectively reviewed our experience with stent-reconstruction procedures of the aortoiliac bifurcation from January 1998 through June 2005. The impact of demographic variables, vascular risk factors, disease location and characteristics, stent material and design, and stenting configuration on stent patency was assessed using univariate and multivariate analysis. In particular, we evaluated the effect of geometric mismatch between the protruding segment of the stents and the distal aortic lumen. Sixty-six patients underwent aortobi-iliac stent reconstruction. Indications were bifurcation or bilateral proximal iliac disease in 52 patients and unilateral ostial disease requiring contralateral protection in 14 patients. Limited disease (TASC A and B) was present in 40 limbs in 19 patients; extensive/diffuse disease (TASC C and D) was present in 78 limbs in 47 patients. Complete occlusions were present in 37 limbs in 28 patients (bilateral in nine patients). Self-expanding stents were used in 56 procedures and balloon-expandable stents in 10. Crossing configuration was used in 43 procedures, while abutting configuration was used in 23 procedures. Technical success was achieved in 62 patients (94%), with all four failures due to inability to cross a chronically occluded limb. Three of these patients underwent aortomono-iliac stenting with a crossover femoral-femoral bypass graft, with the remaining one opting for no further interventions. Median combined follow-up was 37 +/- 27 months (range 0-102). Hemodynamically significant restenosis developed in nine patients (14%). The management of restenosis was endovascular in eight patients and was successful in all (balloon dilation in four, restenting in three, thrombolysis and stenting in one) and operative in one patient who developed aortic occlusion and underwent aortobifemoral grafting. Survival table analysis showed primary and assisted patency rates at 4 years of 81% and 94%, respectively. The mortality rate during follow-up was 19 (cardiac cause in eight, pulmonary cause in three, and malignancy in five). Univariate analysis showed radial mismatch (aortic lumen dead space around the protruding segment of the stents), female gender, prior occlusion, and residual stenosis to be significant predictors of restenosis. Multivariate logistic regression analysis showed radial mismatch to be the only significant determinant of restenosis, although the statistical power of the model was limited by the small number of restenoses. Stent reconstruction of the aortoiliac bifurcation for occlusive disease is effective and durable, even with complex aortoiliac disease and long segment occlusions. Most restenoses are amenable to endovascular treatment, with excellent long-term assisted patency. Geometric variables related to individual aortic anatomy and disease pattern (patient-dependent) and stenting configuration (operator-dependent) may have an impact on long-term patency.

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).

Renal hilar doppler analysis is of value in the management of patients with renovascular disease

BACKGROUND An increasing interest in the role of Doppler ultrasound and duplex scan in screening for renovascular hypertension has recently been noted. We conducted this study to define the role of renal hilar Doppler ultrasound (RHDU) in evaluating renal artery stenosis and its value in the postoperative follow-up after renal revascularization. METHODS One hundred and fourteen patients are included in this study with a mean age of 63.7 (11 to 89) years. Seventy-two patients underwent renal revascularization. The most frequent revascularization procedure was renal artery bypass in 82%. The RHDU results were compared with 130 angiograms done within 1 month of the RHDU study. The Doppler velocity signal in a segmental artery in the renal parenchyma was recorded, and the waveform was analyzed. An acceleration index (AI) less than 3.78 KHz/sec/MHz and an acceleration time (AT) greater than 0.1 seconds were used to indicate the presence of a significant renal artery stenosis. RESULTS The overall technical success rate of all RHDU studies was 93.5%. The AI value was higher in the group of patients with normal renal arteries than those with a stenosis (4.7 +/- 1.4 KHz/sec/MHz versus 1.23 +/- 1.13 kHz/sec/MHz, respectively, P <0.0001), and the AT was lower in the former group compared with the latter (0.052 +/- 0.011 sec versus 0.122 +/- 0.069 sec, P <0.0001). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for AI were 89%, 92%, 85%, 94%, and 92%, respectively; and for AT were 62.5%, 97.5%, 91%, 86.5%, and 87% respectively. There was a significantly high agreement between the AI and AT results and those of arteriography (Kappa of 0.82 and 0.66, respectively, P < 0.0001). There were 10.6% kidneys with multiple renal arteries by arteriography. In these kidneys the accuracy was lower for both AI and AT and the agreement with arteriography was nonsignificant. In the postoperative period the accuracy of RHDU was 86% for AI and 95% for AT. CONCLUSIONS Renal hilar Doppler ultrasound has a high accuracy and agreement with arteriography in the diagnosis of renal artery stenosis. Its value is limited by the presence of multiple renal arteries, renal artery occlusion, and high incidence of postoperative false-positive results. It can be useful as a noninvasive screening test for patients suspected of having renal artery stenosis and for surveillance following renal revascularization.

High-resolution multiphase contrast-enhanced three-dimensional MR angiography compared with two-dimensional time-of-flight MR angiography for the identification of pedal vessels

PURPOSE The authors prospectively evaluated optimized multiphase high-resolution (HR) Gadolinium (Gd)-enhanced three-dimensional (3D) magnetic resonance (MR) angiography and standard two-dimensional (2D) time-of-flight (TOF) MR angiography for their ability to delineate distal calf and pedal vessels. MATERIALS AND METHODS Twelve patients (20 limbs) with limb-threatening peripheral arterial occlusive disease underwent HR Gd-enhanced and 2D TOF MR angiography to identify targets for distal bypass. Imaging of the region of the ankle and foot was performed on a 1.5 T system with a head coil. A standard 2D TOF MR angiography sequence was performed first. The HR Gd-enhanced MR angiography sequence was then performed after injection of 0.01-0.2 mmol/kg of gadodiamide, allowing the acquisition of multiple consecutive coronal partitions, each in 18-25 seconds. Two experienced angiographers independently analyzed both studies. Comparison with intraoperative conventional angiography was available in 10 limbs. RESULTS HR Gd-enhanced MR angiography allowed significantly faster imaging time (P <.0001) and larger coverage area (P <.0001) than 2D TOF MR angiography. All segments seen on 2D TOF MR angiography were visualized on HR Gd MR angiography, and significantly more suitable targets were seen well on HR Gd-enhanced MR angiography than on 2D TOF MR angiography (mean targets per limb: 3.9 +/- 1.9 vs 2.6 +/- 1.5, respectively; P =.02). In addition, HR Gd-enhanced MR angiography allowed better visualization of the arcuate pedal branch than 2D TOF MR angiography (P <.0001). Excellent correlation was demonstrated between HR Gd-enhanced MR angiography and intraoperative angiography in 29 segments (binary similarity coefficient, 0.90). A significantly higher percentage of artifacts adversely affected image interpretation with 2D TOF MR angiography than with HR Gd-enhanced MR angiography (14 limbs vs five limbs, P <.001). Artifacts on HR Gd-enhanced MR angiography included suboptimal mask in two limbs, venous contamination in one patient (two limbs), and motion artifact in one limb, although the studies remained diagnostic in all cases. CONCLUSION HR Gd-enhanced MR angiography identified more distal target vessels with greater confidence than 2D TOF MR angiography. Optimized HR Gd-enhanced MR angiography may replace 2D TOF MR angiography as the gold standard examination for evaluation of distal runoff.

Endovascular recanalization of total occlusions of the mesenteric and celiac arteries

OBJECTIVE To evaluate our experience with the endovascular treatment of total occlusions of the mesenteric and celiac arteries. METHODS We performed a retrospective review of endovascular stenting of 27 nonembolic total occlusions of the superior mesenteric artery (SMA) and celiac artery (CA) between July 2004 and July 2011 (26 patients, 16 females; mean age, 62 ± 13 years). A variety of demographic, lesion-related and procedure-related variables were evaluated for potential impact of technical success and patency. The follow-up protocol included clinical assessment, and color and spectral Doppler evaluation of the stented vessel(s). RESULTS The clinical presentation was chronic mesenteric ischemia in 12 patients, acute mesenteric vascular syndromes in 10 patients, foregut ischemia/ischemic pancreatitis in three patients, and prior to endovascular repair of aortic aneurysm in one patient. The treated vessel was SMA in 22 procedures, CA in three, and both SMA and CA in one. Technical success was achieved in 23 of the 27 attempted recanalizations (85%). Three patients who failed the attempt underwent open bypass, and another one underwent retrograde recanalization and stenting of the SMA. Procedure success was only significantly related to patient age <70 years or procedure performance after the year 2006. Notably, the presence of a stump, ostial plaque, extensive vascular calcification, recanalization route (intraluminal vs subintimal), occlusion length, and vessel diameter had no significant impact on procedure success. Traditional duplex criteria proved unreliable in predicting restenosis. Life table analysis of freedom from symptom recurrence showed a primary and assisted rates of 58% and 80% at 1 year, and 33% and 60% at 2 years, respectively. Clinical recurrences developed in six patients (four presented with abdominal angina and weight loss, two presented with abdominal catastrophe). There were six access-related complications and no procedural deaths. Four delayed deaths occurred during follow-up (two cardiac causes, two due to abdominal sepsis). CONCLUSIONS Endovascular recanalization of mesenteric artery occlusion is both feasible and successful, provided careful planning is used.

Late results of a prospective study of direct intra-arterial urokinase infusion for peripheral arterial and bypass graft occlusions.

The outcome of 72 direct intra-arterial urokinase infusions was studied prospectively. Thirty four were performed for native arterial occlusion and 38 for bypass graft occlusion; the immediate success rates were 67.5 and 84% respectively. The overall incidence of complications was 26%. Median follow-up was 36 (range 1-60) months. Seventeen patients (27%) died during follow-up; nine (14%) required a major amputation. Among patients with native arterial occlusion, 29% had no adjunctive procedure after thrombolysis; of these patients, 85% remained patent at a median of 21 (range 3-42) months. Among bypass occluded patients, only two (6%) had no lesion revealed after successful lysis; both bypasses remain patent at 54 and 58 months respectively. For patients treated with balloon angioplasty immediately after successful thrombolysis, 62% with native arterial occlusion remained patent at a median of 39 (range 2-60) months, whereas only 27% of bypass occlusion patients were patent at a median of 11 (range 2-40) months. Of patients requiring a surgical procedure after thrombolysis, 23 new bypasses (15 vein, eight prosthetic) were placed (nine in native arterial occlusion patients, 14 in bypass occlusion patients). In addition, there were 15 other surgical procedures, including six thrombectomies, four vein patch angioplasties, four vein jump grafts and one endarterectomy. The primary and secondary patencies for the 15 new vein bypasses placed were 81 and 88% respectively at a median follow-up of 36 months. Good immediate results were experienced with urokinase thrombolysis for peripheral arterial and graft occlusions. However, multiple adjunctive procedures were required to maintain patency.(ABSTRACT TRUNCATED AT 250 WORDS)

The impact of color duplex surveillance on the outcome of lower limb bypass with segments of arm veins

PURPOSE To evaluate prospectively 42 lower extremity arm vein bypasses with use of color duplex surveillance (CDS). METHODS Twenty-seven bypasses (64%) were to tibial arteries, 12 (29%) were to popliteal arteries, and three (7%) were to superficial femoral arteries. Twelve bypasses were composed of a single arm vein segment, and 30 were composite vein bypasses. Bypasses were evaluated with CDS and ankle-brachial indexes before the patients were discharged from the hospital, at 1 month, and then every 3 months during the first year; every 6 months during the second year; and annually thereafter. The median follow-up period was 17 months, and the median number of scans performed per bypass was seven. Each examination consisted of a scan of the entire bypass with velocity measurements taken routinely at the proximal and distal anastomoses and at a proximal and distal bypass segment in addition to any high-velocity area identified on the CDS. Peak systolic velocity greater than three times that of an adjacent graft segment or peak systolic velocity less than 45 cm/sec throughout the vein conduit were indications for arteriography. RESULTS Thirteen arteriograms were performed because of abnormal duplex findings on surveillance. Extension or interposition vein grafts (9), vein patch angioplasty (1), or inflow procedures (3) were used to maintain secondary patency. The 24-month primary and secondary patency rates were 46% and 85%, respectively. Three patients required amputation of a major extremity. CONCLUSIONS Arm veins are satisfactory conduits for lower extremity revascularization. However, preocclusive lesions that require correction are commonly found on surveillance, especially when composite bypasses are required. Vein bypass surveillance with CDS allows identification and appropriate correction of preocclusive lesions.