Abdominal aortic surgery: prevention of lower limb ischemia.

Lower limb ischemia represents the most common single threat to the success of operations for abdominal aortic aneurysms. It can occur because of distal embolization from a number of sites or because of thrombosis either at sites of anastamosis or in diseased arteries at or beyond sites of clamping. Preoperative angiographic studies in patients with missing lower extremity pulses aid in planning reconstructive procedures if ischemia occurs in the postoperative period. Systemic heparinization during the stage of interruption of the circulation and specific techniques of dissection, clamping, anastamosis, flushing, and unclamping resulted in an incidence of 0.57% postoperative limb-threatening ischemia in a series of 700 abdominal aneurysm operations in which the incidence of lower limb gangrene was 0.28%.

Myocardial infarction following carotid endarterectomy: a review of 683 operations.

In a series of 683 consecutive carotid endarterectomies, there were 16 postoperative myocardial infarctions which resulted in five deaths. Of 399 operations on patients with no previous history of heart disease, there were only two myocardial infarctions (0.5%). Two hundred and eighty-four operations were performed on patients with heart disease, and vasopressors were administered in 135 of these procedures. For these patients the risk of myocardial infarction increased from 2.0% to 8.1% with the use of vasopressors (P less than 0.001). The management of the patient with stable heart disease undergoing carotid endarterectomy is discussed.

Rupture of the vein patch: a rare complication of carotid endarterectomy.

Vein patch closure after carotid endarterectomy has been used to reduce the incidence of residual and recurrent stenosis at the carotid bifurcation. A rare but potential serious complication is rupture of the vein patch during the early postoperative period. In our experience of 2359 carotid operations performed from 1962 through 1986, saphenous vein was used for closure in 2275 (96.5%) operations. In three patients out of 75 in whom the vein patch had been harvested from the ankle, rupture of the patch occurred 2 to 5 days after uneventful carotid surgery. At emergency reoperation, the central portion of the vein was necrotic, with no evidence of infection. In each case the carotid artery was closed again with fresh thigh saphenous vein, and recovery was uneventful. The use of ankle vein was discontinued in December 1983 in favor of groin saphenous vein, and similar complications have not occurred in more than 600 carotid endarterectomies performed since. Early noninfectious ruptures of the saphenous vein patches have been mentioned in other reported series of carotid operations and have often been related to the use of ankle vein, but they remain unexplained.

Intermittent claudication: its natural course.

Of more than 600 patients seen for intermittent claudication by this group and not primarily considered for surgery, 104 had angiographic studies and are the basis for this report. The follow-up period varied from 6 months to 8 years, with a mean of 2.5 years. Classification by severity of claudication revealed 33 with less than one block, 36 with two blocks, and 35 with two or more blocks, foot, calf, or thigh claudication. Eighty-two remained stable or improved and 22 worsened. Of the 22 who worsened, 16 had only worsening of claudication (six of them requiring arterial reconstruction) and six progressed to gangrene and required amputations. Of the 82, 66 either had marked improvement of claudication or remained sufficiently stable not to require any operative intervention. Sixteen required arterial reconstruction for persistent, intolerable, or incapacitating claudication. Five of the six amputees were from the less than one half block claudication group. Angiographic studies were significant only in relation to the below-knee runoff in that three of 25 with less than one vessel runoff, two of 23 with one to two vessel runoff, and one of 56 with two to three vessel runoff came to amputation, regardless of the pattern of more proximal arterial occlusions. The study suggests that intermittent claudication is relatively benign, with only 5.8 percent coming to amputation in a 2.5 year mean follow-up. Prognosis is determined by the severity of below-knee arterial involvement and apparent inability to compensate for ischemia via the collateral circulation since only 12.5 percent of those with the most pronounced involvement came to amputation.

Asymptomatic vena caval fistulization complicating abdominal aortic aneurysm.

Aortocaval fistulization is usually manifested by signs of rupture of an aneurysm or of the large fistula. Absence of symptoms is unusual with this rare complication. Two cases of asymptomatic aortocaval fistula are presented. An awareness of this possibility should facilitate management when unexpected venous bleeding is encountered.

Comparison of results of bilateral and unilateral carotid endarterectomy five years after surgery.

Consecutive patients who successfully underwent carotid endarterectomy (C) between 1970 and 1975 were followed during a 5-year period (mean follow-up 4.3 years). The patients were divided into three groups. Group I comprised 146 patients who had unilateral CE with a patent, nonstenotic contralateral carotid artery. Group II included 45 patients who underwent unilateral CE but whose contralateral internal carotid artery was found to be totally occluded. Group III consisted of 86 patients who underwent bilateral CE. There was no significant difference between the groups with respect to age, sex, neurologic status, or associated diseases, and all were maintained on antiplatelet medications for surgery. During the follow-up period a total of 22 of the 277 patients had a new hemispheric stroke; four others became comatose and died, presumably of stroke. Among the group I patients, 17 had new strokes, only six of which involved the hemisphere ipsilateral to the CE. Five later strokes occurred in group II, one ipsilateral to the CE. Four patients in group III had new strokes. The cumulative stroke rates at 5 years by the life-table method were 17.6% for group I, 16.4% for group II, and 5.6% for group III. The difference between group I and III was significant (P less than 0.05). The results suggest that patients undergoing unilateral CE should have close postoperative monitoring of the contralateral vessel.

Cervical vertebral angioplasty for brain stem ischemia.

Fifty-eight patients underwent unilateral vertebral arterial reconstructions over a 16-year period. Thirty-four underwent carotid operations as well. The first 18 patients underwent vertebral arterial reconstructions in conjunction with carotid endarterectomy as mandated in the Joint Study of Extracranial Arterial Occlusion as a Cause of Stoke. The next 40 underwent vertebral procedures for either brain stem symptoms alone, or for combined cerebral cortical and stem symptoms for specific indications after flow-obstructing carotid lesions had been corrected, but symptoms failed to subside. The surgical procedure consisted of subclavian-vertebral angioplasty except in one patient who underwent a subclavian distal-vertebral bypass graft to the level of the second cervical vertebral body. Syncopal episodes occurred as a major symptom in 16 and was controlled by either carotid and vertebral or vertebral artery operation alone except in four who also required cardiac pacemakers and one who needed correction of aortic stenosis. The long-term follow-up reveals that the stroke rate per average year for the first 14 years of follow-up was 1.2% per patient year with only five strokes having occurred in 410 patient years of follow-up and 70% of the patients having sustained no new neurologic episodes at the fourteenth year. Survival, however, was 45% at the fourteenth year with most deaths caused by myocardial infarction. The surgical procedure of vertebral angioplasty is indicated when bilateral vertebral arterial flow-obstructing lesions are found in patients with brain stem ischemia including drop attacks and syncopal episodes if flow-obstructing carotid lesions have been corrected and symptoms persist. The surgical procedure can be performed with a high degree of safety. The differential diagnosis of drop attacks and syncope in this age group should include, in addition to vertebrobasilar arterial insufficiency, transient cardiac arrhythmias, aortic stenosis, and convulsive disorders.

Long-term results in superficial femoral artery endarterectomy.

Semiclosed femoral popliteal endarterectomy, herein described as extending from groin to knee and performed with an arterial stripper, has proved to be a satisfactory alternative to revascularization of comparable occluded segments of thigh arteries employing autologous saphenous vein. Cumulative patency of 95.7% in all groups initially decreases to 59.6% in claudicators at 5 years and 30.6% in those who had surgery for limb salvage, whereas the limb salvage rate exceeds patency rate, being 62.9% at 5 years.

Dilation of synthetic grafts and junctional aneurysms.

Dilation of prosthetic graft has been noted by authors in association with junctional aneurysm between the synthetic graft and host arteries. Dilation of graft materials was suspected as one of the etiologic factors of the junctional aneurysm. Increase in transverse diameter was observed as early as a few minutes to five years postimplantation in clinical cases. The phenomenon of dilation was studied experimentally. Nine different types of graft materials were tested using intraluminal pulse pressure of 100/60 mm Hg, and the transverse diameters were measured at various time intervals. Knitted grafts showed the more pronounced changes compared with the woven. Degree of dilation differed considerably among the different types of knitted grafts.

Criteria for interpretation of ocular pneumoplethysmography (Gee).

Ocular pneumoplethysmography (OPG) (Gee) is one of the most widely used tests for evaluation of carotid artery disease. Its usefulness depends on its diagnostic accuracy, which depends on the criteria used for interpretation of OPG tracings. Application of different criteria as suggested in the literature by Gee et al, McDonald et al, Baker et al, Eikelboom, and O'Hara et al on 200 OPG tests compared with angiography resulted in variations of sensitivity from 70% to 95%, specificity from 70% to 94%, and overall accuracy from 75% to 90%. In validating OPG, one has to be aware of these substantial differences. We found the criteria of McDonald et al the most suitable for clinical use.

Cerebral protection in carotid surgery.

We performed 956 carotid endarterectomies in 661 conscious patients who were under cervical block anesthesia and in whom the stroke rate was 2.5%. They were analyzed to determine the mechanisms of strokes and the risk factor for perioperative stroke. Twenty-three patients with perioperative strokes, regardless of severity, were analyzed as to the mechanism of cause. One half were due to technical problems, one quarter to intraoperative embolization, one sixth to intracerebral hemorrhage, and the remainder were not directly related to the operative procedures. Perioperative stroke rate varied by group from 0.6% to 28.4%, highest when the contralateral carotid was occluded, where there was a preoperative persistent neurologic deficit, and when the patient failed to tolerate carotid clamping. Regional block monitoring was accurate and no stroke could be ascribed to anesthetic technique. Standard reporting techniques should be used in classifying patients into appropriate risk groups to permit meaningful comparisons among groups using different techniques for cerebral protection.

Symptoms, stenosis, and bruit: interrelationships in carotid artery disease.

The relationship between focal neurologic symptoms, carotid artery stenosis, and cervical bruits was studied in 495 patients. Among the 990 carotid arteries, 562 (57%) were considered to be symptomatic and 505 (51%) were associated with bruit. There was a linear relationship between the degree of stenosis and symptoms. Of the highly stenotic vessels (80% to 99% narrowing), 253 of 350 (72%) were symptomatic; 85 of 104 (82%) occluded vessels were symptomatic. There was a linear relationship between the occurrence of cervical bruit and degree of stenosis, up to but not including total occlusion. The relationship between bruits and focal neurologic symptoms was less direct. Among 562 symptomatic arteries, 297 (53%) had a bruit and 265 (47%) did not. In symptomatic patients, the absence of a cervical bruit should not delay a workup for extracranial vascular disease.

Revascularization of the external carotid artery.

Numerous reports describe the relative effectiveness of external carotid artery (ECA) revascularization in patients with ipsilateral internal carotid artery occlusion. Most, however, suffer from small numbers of patients or lack of detailed follow-up data. In addition, controversy persists regarding the safety with which this procedure can be performed. Twenty-two patients underwent a total of 27 ECA revascularizations. There were no perioperative strokes or deaths. During a mean follow-up period of 46 months, no strokes occurred and only two patients suffered transient ischemic attacks. Revascularization of the ECA is an effective means of treating the patient with ipsilateral internal carotid artery occlusion and may be performed with minimal morbidity and mortality.

The totally occluded internal carotid artery. Preliminary observations using rapid sequential computerized tomographic scanning.

Cerebral angiography often cannot distinguish between complete thrombosis or fibrosis of the internal carotid artery (ICA) and nonvisualization due to a total occlusion of the common carotid or origin of the ICA. Whereas surgery may be beneficial if the distal carotid is patent (type 1), thromboendarterectomy may be contraindicated if thrombus or fibrosis extend to the intracranial branches (type 2). Rapid sequential computerized tomography (RSCT) was used to examine 15 patients whose ICAs appeared occluded by angiography. Of four ICAs classed as type 1 by RSCT, three were found to be patent during surgical exploration, and carotid reconstruction was successfully performed. Three other ICAs classed as type 2 by RSCT were also surgically explored, and complete thrombosis was confirmed. The RSCT technique provides an effective and nonoperative means of determining whether a nonvisualized ICA is reconstructible.

Management of acute aortic occlusion.

Acute aortic occlusion is most often seen in elderly patients with advanced cardiac disease. The management of these patients has been facilitated by the use of extraanatomic bypass. Over the past 2 years, six patients aged 55 to 87 years presented to our medical center with acute aortic occlusion, three after major operative procedures. One patient had a thrombosed abdominal aortic aneurysm; in the other five patients differentiation between saddle embolus and thrombosis of the distal aorta was impossible. There was one operative death. Four of the other five patients underwent axillobifemoral bypass and one underwent aortofemoral thrombectomy. All survived, and none required amputation. Two of the three patients who underwent preoperative aortography developed transient renal failure postoperatively. Aortography is of little value in diagnosis and is probably contraindicated in acute aortic occlusion. Our recommendation for operative management includes (1) preparation of the patient for possible axillobifemoral bypass, (2) angiography of distal runoff via both femoral arteries, (3) attempt at bilateral aortofemoral embolectomy with Fogarty catheters, and (4) axillobifemoral bypass if embolectomy fails to restore normal pulsatile flow.

Long-term follow-up of patients undergoing carotid endarterectomy in the presence of a contralateral occlusion.

BACKGROUND: Patients with stenosis of one carotid artery and occlusion of the contralateral carotid artery (stenosis-occlusion) who are treated medically are at high risk for stroke. We have recently reported that carotid endarterectomy on the stenotic artery has a low perioperative risk in these patients. We now present follow-up data to define the long-term effectiveness of this operation. PATIENTS AND METHODS: From 1985 to 1991, 135 patients with stenosis-occlusion underwent endarterectomy of the stenotic carotid artery. Selective intra-arterial shunting was performed based on mental status changes under regional anesthesia, preoperative neurologic deficit, or evidence of preoperative cerebral infarction on computed tomography scan. Shunting was used in 70 patients (52%). Saphenous vein was used for patch closure in 132 patients (98%), and polytetrafluoroethylene in 3 (2%). RESULTS: By life-table analysis, 92% of patients have remained stroke-free at 5 years. Fourteen deaths, none related to cerebrovascular disease, have occurred during follow-up. The life-table cumulative stroke-free survival rate at 5 years is 74%, and the overall survival rate is 82%. CONCLUSION: Carotid endarterectomy in the presence of a contralateral occlusion provides long-term benefit to the patient with respect to prevention of stroke. With lower perioperative stroke rates and proven long-term benefit, carotid endarterectomy of the stenotic artery should be the treatment of choice in the patient with stenosis-occlusion.

Beta blockade to decrease silent myocardial ischemia during peripheral vascular surgery.

The incidence and duration of intraoperative silent myocardial ischemia have been shown to be significantly correlated with the incidence of perioperative myocardial infarction in patients undergoing peripheral vascular surgery. To assess the effectiveness of intraoperative beta blockade in limiting such silent myocardial ischemia, a group of 48 patients was treated with oral metoprolol immediately prior to peripheral vascular surgery. The total duration of intraoperative silent myocardial ischemia, the percentage of intraoperative time silent myocardial ischemia was present, the number of intraoperative episodes of silent myocardial ischemia, and the intraoperative heart rate in the treated patients were compared with those in 152 similar but untreated peripheral vascular surgery patients. The patients treated with oral metoprolol had significantly less intraoperative silent ischemia with respect to relative duration and frequency of episodes, a significantly lower intraoperative heart rate, and less intraoperative silent myocardial ischemia in terms of total absolute duration. These results suggest that beta-adrenergic activation may play a major role in the pathogenesis of silent myocardial ischemia during peripheral vascular surgery.

Axilloaxillary bypass for symptomatic stenosis of the subclavian artery.

Since the association has been made between stenosis of the subclavian artery and neurologic symptoms, controversy has existed over the preferred surgical procedure for bypass. In addition, concern has been raised regarding the long-term patency and effectiveness of this extraanatomic procedure in relieving neurologic symptoms. Twenty-seven patients underwent this operation for posterior cerebral symptoms between 1973 and 1982; 25 were followed for up to 77 months (mean 26 months). Twenty-two patients had complete relief of symptoms, although 3 of them required a subsequent carotid endarterectomy. Two other patients had partial relief, and one patient's symptoms remained unchanged. Upper extremity symptoms, present in nine patients, were relieved by the operation. All grafts remained patent during follow-up. Axilloaxillary bypass is a durable procedure for symptomatic stenosis of the subclavian artery. It is a low-risk procedure and is therefore particularly suited for older patients with associated carotid artery disease.

Lower-limb amputation for occlusive vascular disease.

A small series of 58 patients who required amputation because of gangrene of the lower limb with nonreconstructable arteries at New York University Medical Center illustrates the manner in which application of some of these principles achieved primary healing of 78% in below-knee amputation and rehabilitation rate of as high as 90% using simple nonrigid dressings.

Ocular pneumoplethysmography (OPG-Gee) in noninvasive evaluation of carotid artery stenosis.

Carotid artery stenosis can be evaluated noninvasively by ocular pneumoplethysmography (OPG-Gee). This simultaneously measures both ophthalmic artery pressures and is therefore capable of detecting pressure-reducing or hemodynamically significant carotid lesions. An OPG-angiography correlation was made for 200 carotid arteries in 110 patients. Sensitivity, specificity and overall accuracy were 91%, 89%, and 90% respectively, if calculated per artery. On a per patient basis these figures were 94%, 88%, and 91%. Applications of this rapid and simple technique in clinical practice include selection of patients for angiography and carotid endarterectomy, as well as early and late control of the operative results.