Victor J. Weiss

Acute occlusion of the abdominal aorta

BACKGROUND Acute aortic occlusion most commonly results from aortic saddle embolus or thrombosis of an atherosclerotic abdominal aorta. The purpose of this study was to review the experience at a university hospital to better define the diagnosis and management of this uncommon process. METHODS A retrospective chart review was performed from patients admitted to Emory University Hospital with acute occlusion of the abdominal aorta from 1985 through 1997. RESULTS Thirty-three patients were identified. In group EMB (n = 16), occlusion was due to saddle embolus. In group IST (n = 17), occlusion was attributed to in situ thrombosis of a severely diseased aorta. Operative procedures performed included transfemoral embolectomy (15), aorto-bifemoral bypass (9), axillobifemoral bypass (5), fasciotomy (3), and thrombolysis (1). The in-hospital mortality rate was 21% (31% EMB, 12% IST), and morbidity was significant and included mesenteric ischemia (6%), bleeding complications (9%), subsequent amputation (12%), renal failure (15%), recurrent embolization or thrombosis (21%), and cardiac complications (42%). CONCLUSIONS Acute aortic occlusion has tremendous morbidity and mortality even with optimal surgical care.

Endovascular repair of abdominal aortic aneurysms: risk stratified outcomes.

ObjectiveThe impact of co-morbid conditions on early and late clinical outcomes after endovascular treatment of abdominal aortic aneurysm (AAA) was assessed in concurrent cohorts of patients stratified with respect to risk for intervention. Summary Background DataAs a minimally invasive strategy for the treatment of AAA, endovascular repair has been embraced with enthusiasm for all prospective patients who are suitable anatomical candidates because of the promise of achieving a durable result with a reduced risk of perioperative morbidity and mortality. MethodsFrom April 1994 to March 2001, endovascular AAA repair was performed in 236 patients using commercially available systems. A subset of patients considered at increased risk for intervention (n = 123) were categorized, as such, based on a preexisting history of ischemic coronary artery disease, with documentation of myocardial infarction (60%) or congestive heart failure (35%), or due to the presence of chronic obstructive disease (21%), liver disease, or malignancy. ResultsPerioperative mortality (30-day) was 6.5% in the increased-risk patients as compared to 1.8% among those classified as low risk (P = NS). There was no difference between groups in age (74 ± 9 years vs. 72 ± 6 years; mean ± SD), surgical time (235 ± 95 minutes vs. 219 ± 84 minutes), blood loss (457 ± 432 mL vs. 351 ± 273 mL), postoperative hospital stay (4.8 ± 3.4 days vs. 4.0 ± 3.9 days), or days in the ICU (1.3 ± 1.8 days vs. 0.5 ± 1.6 days). Patients at increased risk of intervention had larger aneurysms than low-risk patients (59 ± 13 mm vs. 51 ± 14 mm;P < .05). Stent grafts were successfully implanted in 116 (95%) increased-risk versus 107 (95%) low-risk patients (P = NS). Conversion rates to open operative repair were similar in increased-risk and low-risk groups at 3% and 5%, respectively. The initial endoleak rate was 22% versus 20%, based on the first CT performed (either at discharge or 1 month;P = NS). To date, increased-risk patients have been followed for 17.4 ± 15 months and low-risk patients for 16.3 ± 14 months. Kaplan-Meier analysis for cumulative patient survival demonstrated a reduced probability of survival among those patients initially classified as at increased risk for intervention (P < .05, Mantel-Cox test). Both cohorts had similar two-year primary and secondary clinical success rates of approximately 75% and 80%, respectively. ConclusionsEarly and late clinical outcomes are comparable after endovascular repair of AAA, regardless of risk-stratification. Notably, 2 years after endovascular repair, at least one in five patients was classified as a clinical failure. Given the need for close life-long surveillance and the continued uncertainty associated with clinical outcome, caution is dictated in advocating endovascular treatment for the patient who is otherwise considered an ideal candidate for standard open surgical repair.

ENDOVASCULAR TREATMENT OF VASCULAR INJURIES

The endovascular management of hemodynamically stable patients with traumatic vascular lesions is an appealing concept. In principle, many of the injuries detected at the time of diagnostic angiography can be treated at the same setting. Moreover, lesions that occur at the base of the skull or at infraclavicular and pelvic locations pose far less difficulty when managed by transcatheter techniques than by traditional surgical exposure. Even among more accessible injuries, standard surgical dissection is often complicated by the presence of hematoma or pseudoaneurysm, which causes obliteration of natural tissue planes, or arteriovenous fistulas that may complicate dissection because of associated regional venous hypertension. Thus, endovascular approaches may provide easier access to the target lesion, limit the morbidity often associated with surgical exploration, and reduce transfusion requirements. Nonetheless, the long-term consequence of placing an intravascular foreign body in a young patient is undefined, and the potential risk for a device infection cannot be ignored. Definitive answers to these issues await the outcome of longitudinal follow-up studies. Until that time, a prudent approach in the use of this new technology is appropriate.

Endovascular Revascularization of Renal Artery Stenosis in the Solitary Functioning Kidney

The treatment of renal artery stenosis by angioplasty and stenting is an effective and accepted alternative to surgery for the treatment of renovascular hypertension and preservation of renal function. We report the technical and clinical outcomes of renal artery stenting in patients with a solitary functioning kidney and renal artery stenosis. From October 1993 to November 1999, 30 stents were placed in the renal arteries of 27 patients (mean age 72+/-8 years) with a solitary functioning kidney and azotemia. The mean diameter renal artery stenosis was 86+/-14%. The mean preprocedure serum creatinine (Cr) level was 3.0+/-1.5 mg/dL (range 1.5-7.5 mg/dL), arterial blood pressure was 171+/-29/85+/-13 mmHg, and the number of antihypertensive drugs was 2.9+/-1.1. Indications for stenting were suboptimal balloon dilation (n = 16), intimal dissection (n = 6), and restenosis following angioplasty (n = 5). Atherosclerotic ostial lesions were present in 25 (93%) of 27 renal arteries. This represents the largest series of renal artery stenting in patients with a solitary functioning kidney, and demonstrates this treatment modality to be a relatively safe alternative to conventional surgery in this high-risk patient group. Most (74%) of the patients in this series had improved or stabilized renal function. Further efforts to define preprocedural indicators of success are necessary to identify the patients who may benefit from revascularization of their solitary kidney.

Epidural analgesia in patients with chronic obstructive pulmonary disease undergoing transperitoneal abdominal aortic aneurysmorraphy--a multi-institutional analysis.

INTRODUCTION Patients with chronic obstructive pulmonary disease (COPD) are more likely to develop pulmonary morbidity following major abdominal surgery. The purpose of this study was to examine the utility of epidural analgesia in patients with COPD who underwent elective transperitoneal abdominal aortic aneurysm (AAA) repair. METHODS During a 7-year period, all patients diagnosed with COPD undergoing elective AAA repair (n=425) from three hospitals were reviewed. Inclusion criteria were an FEV(1)/FVC ratio <75% and/or a PaCO(2)>45 mmHg. Clinical outcomes were compared between those who received epidural analgesia (epidural group) and those who did not (control group). Primary endpoints measured were duration of intubation, ICU stay, hospital days, and pulmonary complications. RESULTS Strict inclusion criteria were met by 131 patients, which included 86 patients in the epidural group and 45 patients in the control group. When comparing the epidural vs. control group, the mean AAA size was 6.3+/-0.9 cm vs. 6.0+/-1.5 cm (NS), FEV(1) was 57.2+/-24.7% vs. 49.0+/-10.3% (NS), and the mean FEV(1)/FVC ratio was 52.0+/-11.4% vs. 50.6+/-6.7% (NS), respectively. The epidural group had a significantly lower incidence of post-operative ventilator dependency and ICU stay (p<0.05), as well as a decreased trend in pulmonary complications when compared to the control group. The overall hospital stay remained similar between the two groups. The relative risk of developing a pulmonary complication in the absence of epidural analgesia was 2.3. CONCLUSIONS Perioperative epidural analgesia is beneficial in patients with COPD undergoing AAA repair by reducing both the post-operative ventilator duration and ICU stay. Epidural analgesia should be considered in all COPD patients undergoing elective transperitoneal AAA repair.

A porcine model of carotid artery thrombosis for thrombolytic therapy and angioplasty: application of PTFE graft-induced stenosis.

Purpose: To develop a porcine carotid artery thrombosis model for the evaluation of thrombolytic therapy and adjunctive angioplasty procedures. Methods: Bilateral carotid thrombosis was induced in 16 pigs using endothelial crush injury followed by external polytetrafluoroethylene (PTFE, 5 × 2 cm2) wrap placement to create segmental carotid stenosis. Light microscopy was used to examine thrombus composition. Selective carotid catheterization was performed via a femoral approach. Two hours following carotid artery occlusion, a urokinase (250,000 IU) and heparin (1000 U) solution was pulse-sprayed in 1 carotid artery while the contralateral vessel received the control saline vehicle. The efficacy of thrombolytic therapy was assessed using carotid arteriography and intravascular ultrasound. The feasibility and technical efficacy of balloon angioplasty within the carotid stenosis model were also evaluated. Results: Carotid artery occlusion occurred in 30 ± 6 minutes following endothelial injury plus PTFE wrap placement. Histological examination of carotid arteries showed endothelial irregularity with fibrin-rich and platelet-rich thrombus. Urokinase was effective in recanalizing all occluded arteries (100%), while the control saline vehicle showed no effective thrombolysis (p < 0.001). Angioplasty was successful in restoring normal diameter in all arteries (100%). Conclusions: This carotid artery thrombosis model, which incorporates intimal injury with segmental stenosis, is simple to create and reproducible. It provides not only a model for the evaluation of thrombolytic therapy but also a practical training tool for adjunctive endovascular interventions.

Endoscopic Vein Harvest Techniques for Coronary and Infrainguinal Bypass

Endoscopic saphenous vein harvest represents a minimally invasive approach to obtain a suitable bypass conduit for coronary or extremity revascularization. Endoscopic vein harvest has been designed to reduce wound complications in a population typically at risk for problematic wound healing. Most studies have shown a reduction in such wound healing complications and improved patient comfort, which may result in fewer postoperative visits. The technique of endoscopic saphenous vein harvest is described, and the current limitations of the procedure are discussed. Copyright

Minimally invasive vascular surgery : Review of current modalities

The concept of a minimally invasive approach to the treatment of vascular pathology was realized nearly 30 years ago when Charles Dotter described dilatation of atherosclerotic stenoses. Since that time biotechnology and therapeutic innovation have progressed to the point where entire medical subspecialties are based on the endoluminal treatment of diseases of the blood vessels. The most rapid progress has been made in the area of endoluminal treatment of vascular lesions, with angioplasty, stent, and stent graft deployment becoming an increasingly common method of treating various vascular lesions. Extraluminal endoscopic treatment of vascular disease has been gaining popularity, particularly for management of perforator vein incompetence associated with venous stasis disorders. Endoscopic saphenous vein harvest has become an accepted method for minimizing the length of incision required for saphenectomy. Vascular imaging has followed similar trends, with more detailed information being derived from tiny intravascular ultrasonic catheters. This article summarizes the current state of minimally invasive vascular surgery to provide the reader with an understanding of the efficacy of the various modalities. It also discusses future directions in the field.

The LifeSite Hemodialysis Access System in patients with limited access

OBJECTIVE The LifeSite Hemodialysis Access System was recently introduced as a completely subcutaneous device with reported advantages of improved patient comfort and reduced catheter-related infection. The performance of the LifeSite catheter at a single, tertiary-care university medical center was reviewed. METHODS We retrospectively reviewed all patients who underwent placement of the LifeSite catheter between February 2001 and March 2002. Kaplan-Meier analysis was used to determine the probability of patient survival, freedom from catheter-related infection, and freedom from device failure necessitating catheter removal. RESULTS Thirty-six patients who had previously received dialysis for an average of 6.1 years underwent placement of 37 LifeSite catheters. Most patients (95%) were referred for LifeSite placement because they had exhausted all available arteriovenous fistula and graft sites. Mean follow-up was 6.8 months, with a patient survival rate of 81% at 8 months. Primary and secondary patency rates were 62% and 87% at 8 months, respectively. Two patients died from infectious device-related complications. Twelve of 17 patients (71%) with device-related infection did not manifest any signs or symptoms at the valve site. There were 2.4 catheter-related infections and 2.6 device failures requiring removal per 1000 patient-catheter days. Freedom from infection and device removal at 8 months was 46% and 49%, respectively. CONCLUSIONS The LifeSite demonstrated acceptable patency, infection, and device failure rates; however, in patients with limited access, unrecognized infection and death may occur. The LifeSite should not be used as a substitute for a more permanent form of hemodialysis access.

Evaluation of Thrombolysis and Angioplasty in a Porcine Iliac Artery Thrombosis Model: Application of Endovascular Stent-Graft–Induced Thrombosis

PURPOSE To develop a novel endovascular thrombosis model in the porcine iliac artery for the evaluation of thrombolysis and angioplasty. MATERIALS AND METHODS A stent-inversion-graft (SIG) model combining either a 3-mm or 5-mm tapered expandable polytetrafluoroethylene (ePTFE) graft attached within a self-expandable, 10-mm nitinol stent was placed in the left common iliac artery via an ipsilateral common femoral artery approach in 24 pigs. When the iliac artery was thrombosed, urokinase (250,000 IU) plus heparin (1,000 units) were pulse sprayed via a contralateral femoral approach (n = 12). Saline pulse-spray was used as a control group (n = 12). Balloon angioplasty was performed to eliminate the stenotic tapered graft within the stent after successful thrombolysis. The efficacy of the thrombolysis was assessed with use of intravascular ultrasound (IVUS) and arteriogram. RESULTS Both the 3-mm tapered and 5-mm tapered SIG models caused iliac artery occlusion in 22 +/- 5 and 41 +/- 9 minutes, respectively, after the deployment. Luminal patency was re-established successfully in all occluded arteries after urokinase infusion. Angioplasty was successful in eliminating the tapered stenosis and restoring the normal diameter in all iliac arteries treated with urokinase. Complete thrombolysis was achieved in both models treated with urokinase. CONCLUSION This novel endovascular approach of inducing arterial thrombosis is simple to perform and reliably produces arterial thrombosis. The intraluminal stenosis is also amenable to angioplasty. This model is useful for the evaluation of antithrombotic treatment modality and adjunctive endovascular interventions.