Perspectives in Vascular Surgery and Endovascular Therapy

Spinal cord ischemic injury following thoracoabdominal aortic aneurysm (TAAA) repair remains the most devastating complication, which still occurs in 10 to 30°I° of patients, despite protective measures such as distal aortic perfusion, cerebrospinal fluid (CSF) drainage, epidural cooling, and reattachment of intercostal arteries. One of the most important limitations of protective actions is the inability to assess the adequacy of spinal cord perfusion and cord function. We developed a technique to record motor-evoked potentials (MEPs) during thoracoabdominal aortic surgery to assess spinal cord ischemia and evaluate the subsequent protective strategies to prevent neurological deficit. Furthermore, a subpopulation was simultaneously monitored with somatosensory evoked potentials (SSEPs). The surgical protocol included left heart bypass and CSF drainage. When spinal cord ischemia was detected, distal aortic pressure and mean arterial pressure were increased. By means of sequential crossclamping, MEPs were used to identify critical intercostal or lumbar arteries. The results show that monitoring of MEPs allows accurate assessment of spinal cord ischemia. SSEP monitoring does not offer additional benefit because of delayed ischemia detection and a high incidence of false-positive and false-negative results. Surgical stragegies based on MEPs prevented neurological deficits in 97% of patients treated for type I and II TAAA.

The role of cardiac risk assessment and preoperative cardiac intervention prior to elective vascular surgery remains controversial. In high cardiac risk patients (severe or unstable angina, recent myocardial infarction, decompensated congestive heart failure [CHF]), the risk of an adverse cardiac event is so great that most would agree that these patients should undergo a preoperative cardiac work-up. In most instances strong consideration in these patients should be given to proceeding directly to coronary arteriography In patients with low cardiac risk (those with no active cardiac symptoms, and no Eagle risk factors [angina, age >70 years, history of CHF, Q-wave on EKG, diabetes, ventricular ectopy requiring medication]), the adverse cardiac event rate is so low that one can proceed safely to vascular surgery without any additional cardiac testing. The moderate risk group (patients with one or more Eagle risk factors but without severe or recent cardiac symptoms) may potentially benefit from aggressive cardiac intervention. However, the pendulum appears to be swinging toward less preoperative cardiac evaluation in this group as well. Factors that favor a less aggressive approach even in these moderate risk patients include the lower cardiac morbidity and mortality following aortic surgery observed over the last decade, the lack of a good noninvasive cardiac test that is reproducibly predictive of adverse cardiac events, and the absence of data that demonstrate that subjecting a patient to three invasive procedures (coronary arteriography, coronary revascularization, and peripheral vascular operation) is less morbid than proceeding directly to peripheral vascular surgery.

This initial series describes a minimally invasive, endovascular method of performing femoropopliteal in situ saphenous vein (SV) bypass and popliteal artery aneurysm (PAA) embolization. Twenty patients have undergone PAA operations. Eleven patients had conventional SV bypasses with proximal and distal ligation of the popliteal artery (PA), and nine patients underwent PAA embolization and an endovascular in situ SV bypass (EISB). The EISB bypass was performed using an angioscopic guided side branch occlusion coil system, whereas the PAAs were embolized with occlusion coils under fluoroscopic surveillance. After operation in the EISB group there were no deaths, no wound complications, and the mean hospital length of stay (LOS) was 2.1 days. Six operations were performed through two incisions, and three operations required an additional incision. Primary patency was 88% (8/9), and all PAAs remained occluded by color flow ultrasonography at follow-up ranging from 4 to 23 months (mean 11.2 months). In the conventional bypass group there were no deaths, three patients (27%) had wound complications, and the mean LOS was 6.2 days. Bypass patency at 42 months was 91% (10/11). This minimally invasive combined radiological and endovascular surgical technique obviates an extensive incision to harvest the SV and ligate the PAA proximally and distally If long-term endovascular bypass graft patency and PAA occlusion rates prove to be similar to open operative results, the benefits of reduced wound complications, decreased hospital LOS, and increased health care savings support further investigation of this endovascular method for the treatment of PAA.

As the specialty of vascular surgery evolves, vascular surgeons may be asked to assist in the management of patients with locally invasive sarcomas that may require vascular resection or reconstruction.

Since July 1, 1996, we have surgically treated 165 patients with sarcoma. Of these, 11 were considered preoperatively to have potential vascular involvement, with 3 ultimately requiring vascular reconstruction or ligation (Table I). An additional patient with a recurrent nonseminomatous germ cell tumor of the pelvis is included because the natural history reflects that of sarcoma, and the surgical management illustrates important technical points regarding en bloc resection and vascular reconstruction. Patient age ranged from 11 to 75 (mean 46). No patients have been lost to follow-up, which has ranged from 1 to 32 months (mean 13.4 months). Four patients had recurrent tumors during follow-up. Those with the smallest tumors and those not requiring vascular reconstruction had the highest rates of cure to date. There was one death in a 32-year-old female with a large thigh leiomyosarcoma who developed pulmonary metastasis 1 year postoperatively

Four patients required vascular reconstruction. One (patient 2, Table 1) with a metastatic malignant histiocytoma of the groin had persistent disease due to inability to obtain a clear surgical margin. She had refused hip disarticulation. Another (patient 1, Table 1) developed a duodenal recurrence at 1.5 years. He underwent a Whipple resection and is disease-free at 4 months. The remaining two are disease-free at last follow-up.

There were no perioperative deaths. One patient developed a groin wound infection 2 weeks postoperatively that required removal of a proximal superficial femoral artery PTFE interposition graft and common femoral venous interposition graft. Viability of the limb was maintained via profunda collateral, and amputation has not been required. One patient with a prosthetic iliac vein bypass developed a proximal anastomotic stenosis at 3 months, which was successfully treated with balloon angioplasty and stent placement. Repeat angioplasty was required 1 year later, and he subsequently remains asymptomatic at 8 months.

Herein we present the lessons learned in our experience with this unique population of patients. Successful outcome for these cases requires extensive preoperative planning and collaboration among all physicians involved in the patient's care.

Although vascular specialists are well informed about the aortoiliac and femoral distal arterial trees, the hypogastric circulation remains a terra incognito to most. Patients may have significant or chronic or, rarely, pelvic arterial insufficiency This paper summarizes the anatomy and pathophysiology of this problem and outlines diagnostic options and treatment modalities for the occasional patient presenting with such problems.

The obturator bypass was initially employed to avoid the infected groin during revascularization. In the literature, placement of over 300 obturator bypass grafts has been reported for a variety of indications, although the number of procedures performed was undoubtedly much higher. Important factors that must be considered before performing such a bypass include the proper assessment of adequate inflow, outflow, and the anatomic site of infection or other complicating circumstances. Although different surgical approaches have been advocated by several authors, the technique will ultimately be determined by patient circumstances and physician resourcefulness. A recent review of the literature showed 1- and 5-year patency rates for all indications of obturator bypass to be 71% and 60%, respectively As the procedure is generally safe, this extraanatomic bypass may be used to circumvent a variety of obstacles that preclude a standard revascularization procedure. Therefore, the technique should be included in the armamentarium of the vascular surgeon.

With the advent of new surgical techniques, such as subfascial endoscopic perforator surgery, venous anatomy of the lower limb gained distinguished attention. Here, based on our surgical experience and observations on several dissections, we describe the embryology and the gross anatomy of the superficial, deep, and perforating veins. The lesser and greater saphenous veins, their named tributaries, such as the posterior arch vein, and numerous unnamed small veins form the superficial venous system. Perforating veins drain the superficial into the deep veins. Incompetent superficial, deep and perforating veins may contribute to chronic venous insufficiency. Clinically the most important perforating veins are located in the medial aspect of the leg at just behind the ankle, at 7 to 9 and 10 to 12 cm from the ankle (Cockett I-III) or they are paratibial at 18 to 22 cm proximal from the ankle ("24"-cm perforator). Deep, axial veins, frequently paired, in the lower limb follow their corresponding arteries.

Leg ulcers due to chronic venous disease affect 0.5 to 1% of Western populations. Reflux and/or obstruction of the lower extremity veins are the underlying pathophysiological mechanisms. The superficial venous system is the most common site of venous insufficiency in patients with chronic venous disease; however, the incidence of deep venous insufficiency is increased in patients with venous ulcers. Skin damage is most often associated with multi-system incompetence, and it is rare with deep venous reflux alone. Only 30 to 50% of limbs with ulceration have a documented episode of deep vein thrombosis. Recent developments in the diagnosis of venous disease have allowed more accurate identification of the malfunctioning venous segments and a more rational application of surgical treatment.

This case panel discussion addresses some of the problems and judgment decisions required in a patient with extensive forefoot gangrene, a stenosis of the superficial femoral artery (SFA), and occlusions of all three leg arteries in the mid and upper leg. With extensive foot debridement to the trans-metatarsal level, balloon angioplasty of the SFA, and a vein bypass to the distal anterior tibial artery, a functional foot remnant was saved. The timing of the various procedures, technical details regarding them, and other issues are discussed.