Duplex ultrasound factors predicting persistent type II endoleak and increasing AAA sac diameter after EVAR.

OBJECTIVE: While the significance of type II endoleaks (T2ELs) on the long-term outcome of endovascular abdominal aneurysm repair (EVAR) to repair abdominal aortic aneurysms (AAAs) is debatable, duplex ultrasonography (DU) parameters have been suggested to be predictive of their closure or persistence. The purpose of this study was to determine which, if any, of these variables was associated with persistent T2EL or increased AAA sac diameter. METHODS: Between 1998 and 2009, 278 patients underwent EVAR and post-operative DU surveillance during long-term follow-up (1-11 years) in our accredited non-invasive vascular laboratory by one of three experienced technologists. DU measured intra-sac flow velocity (IFV), spectral doppler waveform (SDW) patterns, post-EVAR sac diameter, and number of T2ELs. RESULTS: T2ELs developed in 14% (38/278) of patients post-EVAR. Fourteen patients had T2ELs that resolved, and sac diameter decreased or remained the same: the average IFV was 42 cm/second; SDW patterns were monophasic in five, biphasic in seven and bidirectional in two; and multiple T2ELs were not present (0%) in any patient. Twelve patients had T2ELs that persisted, but sac diameter decreased or remained the same: the average IFV was 47 cm/second; SDW patterns were monophasic in one, biphasic in five, bidirectional in five, and undetermined in one; and multiple T2ELs were found in 17% (2) of patients. Twelve patients had T2ELs that persisted and were associated with increased sac diameter: the average IFV was 43 cm/second, SDW patterns were monophasic in one, biphasic in two, and bidirectional in nine; and multiple T2ELs were identified in 75% (9) of patients. None of the 38 patients with T2ELs treated with selective surgical or endovascular intervention for enlarging sac diameters (11/12) experienced a ruptured aneurysm. CONCLUSION: Contrary to previous smaller reports of T2ELs and DU surveillance, parameters such as IFV did not correlate with increased post-EVAR sac diameter. The presence of multiple T2ELs and bidirectional SDW may be the strongest factors predictive of increased sac diameter.

Duplex ultrasound imaging alone is sufficient for midterm endovascular aneurysm repair surveillance: a cost analysis study and prospective comparison with computed tomography scan.

OBJECTIVE: Early in our experience with endovascular aortic aneurysm repair (EVAR) we performed both serial computed tomography scans and duplex ultrasound (DU) imaging in our post-EVAR surveillance regimen. Later we conducted a prospective study with DU imaging as the sole surveillance study and determined cost savings and outcome using this strategy. METHODS: From September 21, 1998, to May 30, 2008, 250 patients underwent EVAR at our hospital. Before July 1, 2004, EVAR patients underwent CT and DU imaging performed every 6 months during the first year and then annually if no problems were identified (group 1). We compared aneurysm sac size, presence of endoleak, and graft patency between the two scanning modalities. After July 1, 2004, patients underwent surveillance using DU imaging as the sole surveillance study unless a problem was detected (group 2). CT and DU imaging charges for each regimen were compared using our 2008 health system pricing and Medicare reimbursements. All DU examinations were performed in our accredited noninvasive vascular laboratory by experienced technologists. Statistical analysis was performed using Pearson correlation coefficient. RESULTS: DU and CT scans were equivalent in determining aneurysm sac diameter after EVAR (P < .001). DU and CT were each as likely to falsely suggest an endoleak when none existed and were as likely to miss an endoleak. Using DU imaging alone would have reduced cost of EVAR surveillance by 29% ($534,356) in group 1. Cost savings of $1595 per patient per year were realized in group 2 by eliminating CT scan surveillance. None of the group 2 patients sustained an adverse event such as rupture, graft migration, or limb occlusion as a result of having DU imaging performed as the sole follow-up modality. CONCLUSION: Surveillance of EVAR patients can be performed accurately, safely, and cost-effectively with DU as the sole imaging study.

Is balloon angioplasty of peri-anastomotic stenoses of failing peripheral arterial bypasses worthwhile?

INTRODUCTION: Surgical revision of failing peripheral arterial bypass grafts has generally been shown to provide superior patency rates compared to balloon angioplasty. We analyzed whether balloon angioplasty, specifically of peri-anastomotic stenoses (PAS), provided acceptable patency rates, because surgery for these lesions is more difficult and is likely associated with higher complication rates compared to surgical revision of stenoses in the body of a graft. METHODS: This is a retrospective review of PAS balloon angioplasties performed at a single institution between January 1, 1999, and September 1, 2005. We report ''primary site patency'' as a stenosis treated by balloon angioplasty, ''revised primary site patency'' as a stenosis treated by repeat balloon angioplasty, and ''secondary site patency'' as an angioplastied stenosis treated surgically or when the graft thrombosed and was revised surgically. All procedures were performed in an endovascular operating room based on duplex scan findings suggesting a significant stenosis. RESULTS: 48 PAS in 33 autologous vein and 15 prosthetic grafts were treated by balloon angioplasty in 42 patients. Mean follow-up was 12 months (range, 1-49 months). Interventions were performed on 22 femoropopliteal grafts (11 proximal, 11 distal), 20 femorotibial grafts (5 proximal, 15 distal), 2 axillofemoral grafts (2 proximal anastomoses), 2 popliteal-pedal grafts (1 proximal, 1 distal), and 1 common iliac-femoral graft (proximal). Life-table analysis revealed 2-year primary, assisted primary, and secondary patency rates of 38%, 58%, and 84%, respectively. No major complications occurred with any endovascular intervention. CONCLUSION: Balloon angioplasty of PAS resulted in acceptable 2-year assisted primary patency rate of almost 60%. Endovascular intervention avoided repeat incisions in scarred groins, higher rates of nerve injury and infection, significant blood loss, and longer length of hospital stays. We recommend that balloon angioplasty of PAS be attempted before resorting to surgical intervention, especially in cases of hostile anastomotic wounds.

Comparison of intraoperative completion flowmeter versus duplex ultrasonography and contrast arteriography for carotid endarterectomy.

Intraoperative completion studies of the internal carotid artery following carotid endarterectomy are recommended to ensure technical perfection of the repair. Transit time ultrasound flowmeter does not require trained technicians, requires less time than other completion studies such as duplex ultrasonography and contrast arteriography, and is noninvasive. Flowmetry was compared with duplex ultrasonography and contrast arteriography to determine if the relatively simpler flowmetry could replace these two more widely accepted completion studies in the intraoperative assessment of carotid endarterectomy. Comparative intraoperative assessment was performed in 116 carotid endarterectomies using all three techniques between December 1, 2000 and November 30, 2003. Eversion endarterectomy was performed in 51 cases and standard endarterectomy with prosthetic patching in 65 cases. Patients underwent completion flowmetry, duplex ultrasonography, and contrast arteriography studies of the exposed arteries, which were performed by vascular fellows or senior surgical residents under direct supervision of board-certified vascular surgeons. Duplex ultrasonography surveillance was performed 1 and 6 months postoperatively and annually thereafter. Mean follow-up was 18 months (range, 6-42 months). The combined ipsilateral stroke and death rate was 0%. The mean internal carotid artery flow using flowmetry was 249 mL/min (range, 60-750 mL/min). Five (4.3%) patients had flow < 100 mL/min as measured with flowmetry, but completion contrast arteriography and duplex ultrasonography were normal and none of the arteries were re-explored. One carotid endarterectomy was re-explored based on completion duplex ultrasonography that showed markedly elevated internal carotid artery peak systolic velocity (> 500 cm/sec); however, exploration was normal and completion flowmetry and contrast arteriography were normal. Duplex ultrasonography studies revealed internal carotid artery peak systolic velocities > 150 cm/sec in 15 patients, but flowmetry and contrast arteriography were normal in all 15 cases and none of the arteries were re-explored. There was no correlation between flow rates measured using flowmetry and peak systolic velocities measured using duplex ultrasonography. One abnormal contrast arteriogram showed an intimal flap that was revised, but duplex ultrasonography and flowmetry were normal. Severe recurrent internal carotid artery stenosis developed in 2 patients at 6 and 9 months, but all 3 completion intraoperative studies at the time of the original operation were normal. Based on these results, wide variability in flowmetry values limits its potential usefulness to detect non-flow-limiting lesions and replace contrast arteriography or duplex ultrasonography as an intraoperative carotid endarterectomy completion study. Duplex ultrasonography was also of limited to no value, whereas contrast arteriography rarely documented a lesion that required repair.

Management of juxtarenal aortic aneurysms and occlusive disease with preferential suprarenal clamping via a midline transperitoneal incision: technique and results.

Surgical management of juxtarenal aortic (JR-Ao) aneurysms and occlusive disease may include supraceliac aortic clamping, a retroperitoneal approach, or medial visceral rotation. The authors report their results using preferential direct suprarenal aortic clamping via a midline transperitoneal incision. Between July 1, 1992, and July 31, 2001, they treated 58 patients with JR-Ao disease (44 aneurysmal, 14 occlusive) via a midline incision without medial visceral rotation. Preferential suprarenal aortic clamping was used in 53 cases (42 proximal to both renal arteries, 11 proximal to the left renal artery only) and supraceliac or supramesenteric clamping in 5 cases when there was insufficient space for an aortic clamp between the superior mesenteric artery and renal arteries. This strategy avoided mesenteric ischemia associated with supraceliac clamping in the majority of cases and afforded better exposure of the right renal artery than obtainable with a left retroperitoneal approach or medial visceral rotation. Eleven patients underwent concomitant renal revascularization. Critical adjuncts included the following: (1) selective left renal vein (LRV) division if the vein stump pressure was < 35 mm Hg (suggesting sufficient renal venous collaterals existed), (2) bilateral renal artery occlusion during aortic clamping to prevent thromboembolism, (3) flushing of aortic debris before restoring renal perfusion, and (4) routine administration of perioperative intravenous mannitol and renal-dose dopamine. Patients with type IV thoracoabdominal aneurysms, ruptured aneurysms, or JR-Ao disease approached via a retroperitoneal incision (severely obese patients, re-do aortic surgery) were excluded. No patients died or required dialysis during their hospital stay. The LRV was divided in 12 (21%) cases and reanastomosed in 2 cases (elevated stump pressures). The average suprarenal clamp time was 26 minutes (range, 10-60). Postoperative serum creatinine remained > 0.5 ng/dL above baseline in 3 (5%) patients. These results support suprarenal aortic clamping with a midline transperitoneal incision as the optimal strategy for treating juxtarenal aortic aneurysms and occlusive disease. The authors believe that selective left renal vein division enhances juxtarenal aortic exposure, and routine administration of renal protective agents, along with occlusion of both renal arteries during suprarenal aortic clamping, are critical adjuncts in performing these operations.

Critical pathways can improve results with carotid endarterectomy.

Approximately 10 years ago, the Section of Vascular Surgery at Pennsylvania Hospital reported results of critical pathways that we developed for all major vascular operations, including carotid endarterectomy (CEA). After implementing these pathways, we then developed a specific five-step protocol to further improve results and decrease costs for elective CEA. With the advent of carotid artery balloon angioplasty and stenting (CABAS), CEA has come under increasing attack by endovascular interventionalists. We believe our regimen remains the gold-standard against which CABAS should be compared. Our five-step CEA protocol includes: (1) duplex ultrasonography performed in an accredited vascular laboratory as the sole diagnostic carotid preoperative study, (2) admission the day of surgery, (3) cervical block anesthesia to eliminate intraoperative electroencephalographic monitoring and other costly intraoperative monitoring tests, (4) transfer from the recovery room after a short observation period to the vascular ward, and (5) discharge the first postoperative morning. Since this 5-step protocol was implemented several years ago, we have found it to be safe and cost-effective, and now represents the standard against which CABAS should be compared.