Angiographic and Duplex Grading of Internal Carotid Stenosis: Can We Overcome the Confusion?

The stroke risk reduction benefit of surgical intervention in carotid occlusive disease has been validated in multicenter trials for various angiographically defined lesion severity categories. The two divergent angiographic grading methods used for internal carotid artery stenosis in these trials have caused confusion in the clinical application of their recommendations. Moreover, while today's highly accurate carotid duplex scanning can obviate the need for preoperative angiography in many cases, the duplex criteria must be tailored to achieve sufficiently reliable results on which therapeutic decisions can be made. This review offers a clarification of the discrepancies between the angiographic grading techniques and how their measurements of percent stenosis correlate to the duplex criteria needed to support the treatment decision-making process for carotid obliterative disease.

Intravascular Stapler for “Open” Aortic Surgery: Preliminary Results

OBJECTIVES

The aim of this study was to assess the efficacy of a new stapling device using a pig model.

METHODS

Straight 12 mm Gore-Tex grafts were inserted end to end into the aorta of 12 pigs. One anastomosis was performed with the stapler and the other using 4/0 prolene sutures and 13 mm needles. The animals were sacrificed at one week, one and three months and all grafts underwent histological examination. Leakage from the anastomoses was assessed in a separate specially designed circulation model using saline as a perfusate.

RESULTS

The stapled anastomoses took 1.0+/-0.25 minutes to complete while suturing took 8.5+/-1.5 minutes. There was no difference in the histology between the two types of anastomosis. The leak rate was six times greater at the sutured compared to the stapled anastomosis.

CONCLUSION

The use of stapled anastomoses may allow a significant shortening of aortic cross clamping time, reduce anastomotic leakage and may be particularly useful in laparoscopic aortic repair. A randomised trial is required to assess the efficacy of this device.

Laparoscopic assisted aortic surgery. A review

We give an overview of different laparoscopic assisted techniques to perform aortic surgery. In a meta-analysis the paper describes the combined experience of two vascular surgical centers who together have performed more than 524 laparoscopic assisted aortic procedures. Basically the following techniques can be used to perform a laparoscopic assisted procedure: 1) transperitoneal approach (the Alimi procedure); 2) hand assisted laparoscopy (the Ferrari technique); 3) left retrocolic laparoscopic assisted; 4) combining laparoscopic assisted and total laparoscopy techniques. In all cases a transperitoneal approach was chosen to dissect the aorta. This was either accomplished directly or using a left retrocolic access originally described by Dion as the apron technique. In some cases a hand assist device was used, which permits the surgeon to introduce the non dominant hand while maintaining the pneumoperitoneum. The mortality in abdominal aortic aneurysm (AAA) patients in either center did not exceed 1.8%. ICU stay, postoperative ileus and length of stay were significantly shorter compared to patients with a full length incision. The Pisa group showed that there is still a significant reduction of operating time as well as aortic cross clamping time beyond the learning curve of the first 30 patients. The analysis of the pooled data shows that even in AAA patients the laparoscopic assisted procedure can be performed with operating times of less than 3 h and hospital stays up to 4 days, which we only know from endovascular aneurysm exclusion. This is the first publication of hand assisted laparoscopic endoaneurysm repair involving a large number of patients. The operations can be performed with expediency and safety. We can use these laparoscopic procedures to perform even complex aortic operations including suprarenal aneurysms with revascularization of the renal and visceral arteries. An outlook of future developments including stapling technology is given.

Physiologic and biochemical monitoring during hyperbaric oxygenation: a review

Hyperbaric oxygenation (HBO2) is an important treatment given to various groups of patients exposed to pathologic situations (i.e., carbon monoxide exposure). Since many hyperbaric patients are critically ill and are being treated for life-threatening disorders, it is necessary to monitor various physiologic and biochemical parameters. This is a review of 193 publications covering a wide range of monitored parameters representing metabolic, hemodynamic, respiratory, electrical, and biochemical activities. The significance of monitoring the physiologic, medical, and specific oxygen toxicity effects during HBO2 exposure (MHBO2) is described and emphasized. Further development of new monitoring devices and technologies will enable the improvement of patient management during HBO2 treatment given under various medical conditions. This review also presents new ideas about possible future monitoring of brain function under HBO2 conditions in experimental animals as well as under clinical conditions.

Carotid endarterectomy without angiography

Between 1 January 1990 and 1 September 1994 a total of 109 carotid endarterectomies were performed without preoperative angiography. Only two cases were considered by the surgeon to have a poor correlation between the duplex examination results and intraoperative findings; the outcome was good in both. The perioperative mortality rate was 1.8 per cent, one patient dying from sudden haematoma causing asphyxia and the other from unrelated causes following a myocardial revascularization procedure. Two non-disabling strokes also occurred. These results suggest that carotid endarterectomy based on carotid duplex scanning alone without preoperative angiography is safe in selected patients.

[Carotid endarterectomy without angiography]

Duplex scanning has emerged as an accurate noninvasive method of evaluating patients with extracranial cerebrovascular disease; it has research, clinical and economic implications. The risks associated with cerebral angiography are numerous and well-known. During 1990-1995, 227 carotid endarterectomies (CEA) were performed without preoperative arteriography in 192 patients. 91% were performed under local anesthesia. Indications for surgery without angiography were: renal insufficiency (in 5), allergy to contrast material (11), and need for urgent surgery (25). In 81% CEA was performed due to the preference of both the neurologist and surgeon. In only 2 cases there was a discrepancy in duplex evaluation. 3 patients had postoperative strokes (total stroke rate 1.56%), only 1 of which was disabling (0.52%). 2 died during the immediate postoperative period (mortality 1.04%): 1 on the 2nd postoperative day due to asphyxia caused by a huge neck hematoma which appeared suddenly after discharge (related death, 0.52%); the other died several days after coronary surgery which followed CEA (unrelated death). Our study confirms that patients with well-defined symptoms, appropriate physical findings, and concurrent CT and duplex scans, can safely undergo CEA without preoperative angiography. It is extremely important however, that the duplex scan be a reliable study from a laboratory which has validated its results by sequential comparison of previous duplex and angiographic data. Angiography remains appropriate in patients with atypical symptoms; with conflicting findings between history, physical and duplex data; when there is proximal disease; or in an asymptomatic patient when the duplex scan suggests total occlusion.

Is transcranial Doppler effective in avoiding the hazards of carotid surgery?

The middle cerebral artery flow velocities were measured to test the hypothesis that transcranial Doppler is a useful technique for intraoperative monitoring in 50 consecutive carotid endarterectomies which were performed under local anaesthesia. The patients' neurological status was continuously monitored. The peak middle cerebral artery velocities were measured before clamping, during clamping and after restoration of flow, and again 24 h and 4 weeks later. Clamping produced a decrease in the velocity of the middle cerebral artery, from 97 to 45 cm/s (P < 0.001). Neurological manifestations occurred in eight patients; one patient lost consciousness, and seven experienced transient focal deficits during the procedure. Another three (6%) developed minor strokes postoperatively. The velocity changes were similar in those who developed complications to those who did not. These results do not support the view that transcranial Doppler monitoring is helpful in deciding whether to use a shunt during carotid endarterectomy. Further data are needed to evaluate the importance of transcranial Doppler monitoring during carotid surgery.

Angiographic and duplex grading of internal carotid stenosis: can we overcome the confusion?

The stroke risk reduction benefit of surgical intervention in carotid occlusive disease has been validated in multicenter trials for various angiographically defined lesion severity categories. The two divergent angiographic grading methods used for internal carotid artery stenosis in these trials have caused confusion in the clinical application of their recommendations. Moreover, while today's highly accurate carotid duplex scanning can obviate the need for preoperative angiography in many cases, the duplex criteria must be tailored to achieve sufficiently reliable results on which therapeutic decisions can be made. This review offers a clarification of the discrepancies between the angiographic grading techniques and how their measurements of percent stenosis correlate to the duplex criteria needed to support the treatment decision-making process for carotid obliterative disease.

Renal vein occlusion: a review

PURPOSE

The different etiologies of renal occlusion are reviewed. A special category, division of the left renal vein in abdominal aortic surgery, is also discussed in the review.

MATERIALS AND METHODS

The various diagnostic modalities used in cases of renal vein occlusion include excretory urography, ultrasound, nuclear scan, angiography, venography, computerized tomography and magnetic resonance imaging. The main goals of therapy in this condition should be conserve renal parenchyma and to protect renal function.

RESULTS

The principal mode of treatment is medical and includes correction fluid and eletrocyte imbalance, dialysis, antihypertensive drugs, anticoagulation and in certain cases thrombolysis.

CONCLUSIONS

Renal vein occlusion in adults is usually a result of the vein thrombosis which is frequently associated with the nephrotic syndrome. The anatomy of renal vascularization is of primary importance in understanding its pathophysiological responses and the clinical and diagnostic presentation of patients with this condition. The reaction of the kidney to its vein occlusion is determined by the balance between the acuteness of the disease, extent of the development of collateral circulation, involvement of 1 or both kidneys and the origin of the underlying disease. Renal vein occlusion is generally a complication of some other condition but may also be a primary disease.

Revascularisation for a poorly functioning solitary kidney

Renovascular disease in a solitary kidney is a difficult and challenging problem. In six patients, with a mean age of 62 years, revascularisation was undertaken. In four of them, one to three attempts at PTA were made before the operation but all were unsuccessful. The preoperative mean serum creatine (Cr) was 3.52 mg% (range 2.5-5.5). The stenoses were caused by atherosclerosis in five cases and fibromuscular dysplasia (FMD) in one. Two methods of revascularisation were used: aortorenal bypass with saphenous vein (three patients) or PTFE (two patients), and transaortic renal endarterectomy with a venous patch (one patient). One patient with an aortic aneurysm underwent simultaneous aortic repair with a PTFE graft. There was no mortality or major complications in our series and no patient suffered acute tubular necrosis (ATN) after surgery. The mean follow-up period was 51 months (15-84 months). Postoperative Cr and blood pressure improved in all patients. Four patients no longer required any medication and the other two only needed reduced doses of antihypertensive drugs. Based on our experience of patients with poor single kidney function, we do not recommend PTA in this specific group of patients and suggest an aggressive surgical approach, which can effectively improve solitary kidney function, thus eliminating further haemodialysis.

Cerebral angiography with gaseous carbon dioxide CO2

Large quantities of gaseous carbon dioxide CO2 were rapidly injected into the ascending aorta or common carotid artery of 14 dogs. Good filling of the arteries and intracranial veins was documented by cineangiography or digital subtraction angiography. No adverse effects occurred as a result of this procedure: the electroencephalogram showed no changes throughout the experiments and the dogs were neurologically normal for up to 6 months of follow-up. Further investigation of carbon dioxide as an arterial and cerebrovascular contrast agent is justified based on these results.

CT guided periaortic fluid aspiration diagnosing aortic graft infection

CT guided diagnostic aspiration was performed on a patient suspected of aortic graft infection. The positive aspiration prompted aggressive successful surgical intervention.

Urgent abdominal aortic aneurysm repair in patients over the age 80

We present three patients with successful surgical repair of abdominal aortic aneurysms with signs of imminent rupture in octogenarians. The patients presented with evidence of severe left ventricular dysfunction and reduced compliance either before or during surgery. Extremely cautious delivery of fluids and of after-load reducing agents was employed under the guidance of measurements of cardiac output and filling pressures from a pulmonary arterial catheter inserted prior to surgery.

Ruptured inflammatory abdominal aortic aneurysm due to acute myelomonoblastic leukemia

The extremely rare case of ruptured abdominal aortic aneurysm of inflammatory nature in patient with discovered acute myelomonoblastic leukemia is presented. The difficult problems arising from these, frequently terminal diseases, are discussed.

Practice and theory of "delayed" embolectomy. A 22-year perspective

A study was made of delayed embolectomy in 45 patients (55 limbs). In 5 patients (11%) the cause of arterial embolization was rheumatic heart disease, and 40 patients (89%) suffered from atherosclerotic cardiovascular disease. The study was divided into 3 phases: I (1960-1964), II (1965-1974) and III (1975-1981). In phases II and III surgery was carried out using the Fogarty catheter technique. In 5 patients the embolus was located in the upper extremity. Seven patients died and 8 major amputations were performed within 30 days of surgery. Use of the Fogarty catheter technique and persistent anticoagulant therapy effected 71.8% limb salvage in phase II and 91.6% limb salvage in phase III. Successful revascularization was achieved in 70.9% of the limbs in which peripheral emboli had occurred on an average of 2.7 days prior to surgical intervention. A theoretical basis for the late development of the acute embolic onset is presented.

Extrathoracic approach in surgical treatment of subclavian steal

Between 1979 and 1985 11 selected patients underwent axilloaxillary and carotid-subclavian bypass grafting [dacron or Gore-Tex (USA), 8 mm inner diameter]. Nine patients had lesions in the left subclavian artery and two patients presented with innominate artery obstruction with subclavian-carotid recovery phenomenon. All patients were symptomatic before surgery, and all were relieved of both cerebrovascular and upper extremity ischemic symptoms following surgery. Early graft patency has been excellent. There has been no mortality or serious postoperative complications. Two patients developed late graft thrombosis with recurrent ischemia of the left upper extremity, but there were no neurological symptoms. There has been a follow-up period of up to 6.5 years (mean 38.4 months.) It would appear that the appropriate extrathoracic route of revascularization is the procedure of choice for symptomatic patients with subclavian steal and subclavian-carotid recovery phenomenon.

Local anesthesia in carotid endarterectomy: an alternative method

Results of carotid endarterectomy (41 operations) carried out under local anesthesia are presented. There were no deaths within 30 days. Three patients had undergone surgery with a temporary internal shunt, following signs of neurological changes (unconsciousness, aphasia, motor changes) during 1-min test cross-clamping. No neurologic deficits were observed, and only two patients (4.8%) experienced postoperative hypertension. These data support the view that simple neurological monitoring of awake patients enables accurate assessment of the need for an internal carotid shunt. Carotid endarterectomy under local anesthesia seems to be a very safe procedure. Use of this technique is especially appropriate for elderly patients with hypertension and ischemic heart disease.

Arterio-venous fistula in the lower limb in consequence of Fogarty balloon catheter embolectomy. Case report and review of the literature

Arterio-venous fistula following Fogarty catheter embolectomy is a rare but dangerous complication. The case of a male patient in whom such a fistula was repaired surgically is described. Aggressive approach in the treatment of this severe condition to prevent unnecessary limb loss is advocated. The pertinent literature is reviewed.

Femoral artery flow in deep vein thrombosis: hemodynamics of slow versus acute femoral vein occlusion

There are many reports of reduced flow in the femoral artery following acute occlusion of the femoral vein. Poorer results might also be expected in arterial reconstructive surgery for obliterative vascular disease, in the event of deep vein thrombosis (DVT) of the limb. It is likely that patients develop DVT by a slow process that is totally different from experimental acute occlusion of the femoral vein, which leads to reduction of flow in the femoral artery. To test this hypothesis, a model with slow and gradual femoral vein occlusion was used. The results of this study showed that there was only 13.5% reduction in femoral artery flow during a four-hour gradual occlusion of the femoral vein. This excludes the possibility that in the presence of gradually occurring processes such as DVT, there is a hemodynamic basis for reduced flow through the femoral artery or through a bypass.

Early experience with balloon catheter angioplasty

Percutaneous transluminal angioplasty with the Gruntzig balloon catheter was undertaken in 12 patients with chronic lower limb ischemia. As judged by postdilatation angiography, the procedure was successful in 11 patients (91.6%). Nine patients were either free of symptoms or very significantly improved at follow-up, one to five months after angioplasty. Indications for angioplasty and the technique are described and discussed.