Cameron Akbari

Factors associated with early failure of infrainguinal lower extremity arterial bypass.

OBJECTIVES We analyzed the Veterans Affairs (VA) National Surgical Quality Improvement Program (NSQIP), a large clinical database, to investigate which factors, other than technical, were associated with a higher incidence of early graft failure in infrainguinal bypass. METHODS Data are prospectively collected in NSQIP from 123 participating VA Medical Centers. All patients from 1995 to 2003 in the NSQIP database who underwent infrainguinal arterial bypass were identified by Current Procedural Terminology (CPT) codes (CPT is a registered trademark of the American Medical Association, Chicago, Ill, Copyright 2007). Data for 30-day graft failure were evaluated by univariate analysis, and multivariate logistic regression was used to control for possible confounders. RESULTS The NSQIP database identified 14,788 patients who underwent infrainguinal lower extremity arterial bypasses during the study period, and 723 acute graft failures (4.9%) occurred. On multivariate analysis, compared with patients aged >70 years, patient ages of <50 and 51 to 60 years were significantly associated with early graft failure (odds ratio [OR], 2.2; 95% confidence interval [CI], 1.6-3.0; P < .001; OR, 1.4; 95% CI, 1.2-1.6, P < .001; respectively); age range of 61 to 70 years was not significantly associated with early graft failure. African American race was also associated with early graft failure, and diabetes mellitus had a negative association with early graft failure (OR, 1.4; 95% CI, 1.3-1.5; P < .001; OR, 0.72; 95% CI, 0.58-0.89; P = .002; respectively). Although smoking was a significant factor for acute graft failure on univariate analysis, it was not significant on multivariate analysis. Multivariate analysis of the type of procedure performed revealed that femoral to popliteal bypass with vein or prosthetic graft was associated with better early graft patency than any of the tibial vessel bypass procedures except for popliteal to tibial bypass with autogenous vein. CONCLUSION These data suggest that factors other than technique have an effect on the 30-day graft failure rates of infrainguinal bypasses. These results help the vascular surgeon to predict more accurately early bypass failure rates while planning the procedure and counseling patients about its prognosis.

Endovascular management of acute aortic dissections

INTRODUCTION Acute aortic dissection (AAD) is one of the most common aortic emergencies that vascular specialists are asked to manage. Traditional surgical interventions for cases complicated by malperfusion have resulted in significant morbidity and mortality. With increasing availability of thoracic endografts, endovascular interventions for complicated AAD have become more acceptable. We reviewed our experience with endovascular treatment of AAD since January 2005. METHODS Medical records of patients admitted for AAD from January 1, 2005, to December 31, 2008, were entered into our vascular registry and analyzed for risk factors, extent of dissection, type of management, fate of the false lumen, complications, and survival. There were 249 admissions for aortic dissections during the study period. Our study group included 28 patients with complicated AAD who underwent endovascular intervention. RESULTS During the study interval, 28 patients (16 male) underwent 44 procedures. The average age was 54 years. Risk factors differed from the typical atherosclerotic patient and were dominated by an 89.3% incidence of hypertension. Five patients (17.9%) presented with a history of recent cocaine use. The average length of stay was 25.1 days (range, 1-196 days). Stanford type B dissections were present in all but one patient. Twenty-six thoracic endografts were placed in 25 patients. Eight patients required multiple procedures in addition to a thoracic endograft. Morbidity occurred in 17 (60.7%) patients, with renal insufficiency occurring in 11 patients (39.3%) and one requiring permanent dialysis. Four neurologic events occurred: three strokes (10.7%) and one patient (3.6%) with temporary paraplegia. Three patients (10.7%) died in the periprocedural period, with ruptured dissection in one and pericardial tamponade in another. Eight of 10 computed tomography scans (80%) available for review in follow-up showed complete thrombosis of the thoracic false lumen. CONCLUSIONS Complicated AAD remains a challenging problem, with significant morbidity and mortality rates. However, our early experience with endovascular management offers a favorable reduction in mortality from historic controls.

Graft-free surgical retroperitoneal vascular access as bail-out technique for failed percutaneous approach to transcatheter aortic valve replacement.

BACKGROUND Surgical retroperitoneal access to the iliac artery may provide an alternative route for transcatheter aortic valve replacement (TAVR) in patients with aortic stenosis and prohibitively small common femoral arteries. METHODS Consecutive patients undergoing TAVR via the femoral approach were divided into two groups; standard percutaneous access (n=103) and surgical retroperitoneal access (n=15) for patients in whom dilators could not be advanced without resistance. For retroperitoneal access, proximal groin vessels were exposed surgically and direct puncture was performed. The sheath was tunneled from the level of the initial inguinal puncture site in order to achieve coaxial entry of the sheath into the vessel. RESULTS Baseline characteristics were similar in both groups. Procedural characteristics were insignificantly different between groups; although, procedure time was longer (34 min), while fluoroscopy time and contrast utilization were lower in the retroperitoneal access group. There was no outcome difference between groups. CONCLUSIONS Surgical retroperitoneal access is a reasonable alternative for transcatheter aortic valve replacement in high-risk patients with aortic stenosis who have poor percutaneous access options due to peripheral vascular disease.

Clinical Features and Diagnosis of Peripheral Arterial Disease

Peripheral arterial disease is a fundamental consideration in the patient presenting with a diabetic foot. Although broad in context, it is only part of the overall alteration in vascular structure and function characterized by two distinct pathologic processes: a nonocclusive microcirculatory impairment involving the capillaries and arterioles of the kidneys, retina, and peripheral nerves and a macroangiopathy manifesting as atherosclerotic lesions of the coronary and peripheral arterial circulation. The former is relatively unique to diabetes and is best described as an accelerated microangiopathy rather than an occlusive process. In addition to its well-recognized contribution to the development of diabetic neuropathy, retinopathy, and nephropathy, this microvascular dysfunction is also of paramount importance in the diabetic foot.

Accreditation and credentialing in the vascular laboratory

The vascular diagnostic laboratory remains an integral component of the vascular surgeons practice and has replaced many invasive techniques for the diagnosis and treatment plan of vascular disease. Although financial challenges have been leveled at the vascular laboratory, the actual number of laboratories continues to increase, suggesting a greater demand for vascular laboratory studies. With this, also comes the challenge of maintaining quality within each laboratory as well as ensuring a standard of quality for all laboratories nationwide. Credentialing and accreditation have been used for this purpose in nearly all areas of medicine and have provided a mechanism for assuring a minimum standard of competency. Over the last decade, similar mechanisms have been applied toward the vascular diagnostic laboratory, which likely have resulted in improved vascular diagnostic studies and overall care.

Endovascular Management of Emergent Thoracic Aortic Pathologies

The introduction of thoracic endovascular aneurysm repair (TEVAR) in 2005 facilitated a minimally invasive treatment alternative for complex thoracic aortic pathologies. Symptomatic descending thoracic aortic aneurysm, complicated Stanford type B aortic dissections, and traumatic aortic transections are emergent pathologies that are associated with substantial morbidity, mortality, and a risk of postoperative paraplegia following conventional open reconstruction via thoracotomy and graft replacement. This chapter describes three emergent cases involving the descending thoracic aorta managed endovascularly. We also describe the adjunctive use of intravascular ultrasound (IVUS) to assure accurate aortic measurements and precise TEVAR endoprosthesis placement. TEVAR technology has allowed us to develop rapid and minimally invasive treatment alternatives for these devastating aortic injuries.

Durability of saphenous vein grafts: 44-year follow-up of a saphenous vein interposition graft in a pediatric patient

We report the 44-year follow-up of a 9-year-old girl who underwent a saphenous vein interposition graft in 1964 after suffering extensive pelvic trauma with complete disruption of the right common femoral artery. The patient recovered from this injury and experienced no disability or pain until 2008, when she suddenly developed numbness in the right leg. Evaluation at that time showed a new occlusion of the saphenous vein graft, and she underwent uneventful repeat revascularization with autogenous vein. To our knowledge, this 44-year patency is the longest reported for a saphenous vein graft.