Contralateral Stenosis Research Articles

Clinical follow-up rather than duplex surveillance after carotid endarterectomy.

The value of duplex surveillance and the significance of contralateral carotid disease after endarterectomy have been assessed. Three hundred five patients were observed prospectively after carotid endarterectomy for a median time of 36 months (range, 6 to 96 months), with duplex surveillance performed at 1 day; 1 week; 3, 6, 9, and 12 months; and then each year after endarterectomy. Thirty patients (10%) had ipsilateral symptoms (13 strokes, 17 transient ischemic attacks [TIAs]) at a median time of 6 months (range, 0 to 60 months). Life table analysis demonstrated that ipsilateral stroke was equally common for patients who had > or = 50% restenosis (3% at 36 months) and those who did not (6% at 36 months, p > 0.5). Twenty-three patients (8%) developed symptoms (stroke 5, TIA 14) attributable to the contralateral carotid artery at a median time of 9 months (range, 0 to 36 months) after endarterectomy. By life table analysis, 40% of patients with 70% to 99%, 6% with 50% to 69%, 1% with < 50% contralateral internal carotid stenosis, and 5% with contralateral carotid occlusion at the time of endarterectomy had a contralateral TIA in the 36 months after endarterectomy (p < 0.01). However, contralateral stroke was not significantly more common for patients with severe contralateral internal carotid stenosis demonstrated at the time of endarterectomy (< 50% stenosis, 0%; 50% to 69%, 3%; 70% to 99%, 7%; occlusion, 6% stroke rate at 36 months). Seven of the 32 patients who developed progression of contralateral disease had a TIA, compared with 11 of 227 patients who did not develop progression of contralateral disease (p < 0.01). None of the 12 patients who progressed from a < 70% to a 70% to 99% contralateral stenosis had a stroke. After carotid endarterectomy restenosis is rarely associated with symptoms; contralateral stroke is rare and is not associated with progressive internal carotid artery disease suitable for endarterectomy. This study has shown no benefit from long-term duplex surveillance after carotid endarterectomy. Selective clinical follow-up of patients who have high-grade contralateral stenoses would appear more appropriate.

After Successful Endarterectomy for Symptomatic Carotid Stenosis, Should Any Contralateral but Asymptomatic Carotid Stenosis Be Operated on as Well?

We sought to determine whether there are any subgroups of patients who might benefit from endarterectomy of the asymptomatic carotid artery after successful operation for a symptomatic carotid stenosis. The incidence and outcome of stroke in the asymptomatic carotid artery distribution was prospectively studied in 966 patients who were entered into the European Carotid Surgery Trial and had a 30–99% asymptomatic carotid stenosis. The patients had been randomized to either carotid endarterectomy (61%) or no endarterectomy of their symptomatic carotid stenosis. We reviewed the literature on the risks and efficacy of carotid endarterectomy and used these data in a decision analysis. The 5-year risk of stroke lasting more than 7 days in the asymptomatic carotid distribution was 3.4%. Two independent prognostic factors were identified by means of Cox''s proportional hazards regression with stepwise forward selection: the degree of asymptomatic carotid stenosis (30–69 vs. 70–99%) and hypertension. The 5-year-restricted and quality-adjusted life expectancy for a patient with both a severe (70–99%) asymptomatic carotid stenosis and hypertension, and therefore with the highest risk of asymptomatic carotid distribution stroke, was 4.14 life years for both conservative management and for endarterectomy. Plausible changes in the estimated risk of asymptomatic carotid distribution stroke, and in the rate of complications from endarterectomy, increased the benefit of endarterectomy. But, the maximal benefit was only 0.1 quality-adjusted life years or 5 weeks, even when endarterectomy was without risk. A separate regression model, with the degree of asymptomatic carotid stenosis as a continuous variable, suggested a possible benefit of endarterectomy for the few patients (n = 27, 3%) with an 80–99% asymptomatic carotid stenosis and hypertension. Until our results are refuted in other studies, there seems to be no firm indication for operation on the asymptomatic carotid artery in patients who have been successfully operated for a symptomatic carotid stenosis, except within the context of a randomized controlled trial.

Risk factors for stroke in patients undergoing coronary artery bypass grafting

Objective: To determine predictors of stroke in patients undergoing first-time coronary bypass grafting, we prospectively collected data on 1631 consecutive patients. Methods: Patients with a history of stroke and/or central nervous system symptoms ( n = 134) and/or carotid bruits ( n = 95) underwent carotid Doppler evaluation. Stenosis greater than 70% was considered significant. Patients with symptomatic disease or asymptomatic bilateral disease were referred for combined coronary bypass and carotid endarterectomy ( n = 21). Patients with neurologic symptoms after the operation were assessed by a neurologist and underwent a computed tomographic scan. Events were classified as reversible transient ischemic attack, reversible ischemic neurologic deficit, or irreversible stroke. Results: There were 19 strokes (1.2%) and 20 deaths (1.2%) in this series. In patients with carotid screening, risk of stroke increased with severity of carotid disease and ranged from 0% in patients without stenosis, to 3.2% (1/31) in those with greater than 70% stenosis, and to 27.3% (6/22) in those with carotid occlusion. By stepwise logistic regression analysis six variables were identified as risk factors for stroke. The most important predictor was carotid occlusion with or without contralateral stenosis (odds ratio = 28, 95% confidence interval (8,105). In this group, four of five strokes occurred on the occluded side. Other risk factors were presence of ascending aortic disease at the time of surgery (odds ratio = 12.8, confidence interval 3,48), perioperative myocardial infarction (odds ratio = 8.2, confidence interval 2,33), poor left ventricular function (odds ratio = 4.6, confidence interval 1,19), peripheral vascular disease (odds ratio = 3.2, confidence interval 1,9), and age >60 years (odds ratio = 2.9, confidence interval 0.8,11). Conclusion: We conclude that risk factors for perioperative stroke in patients undergoing coronary artery bypass grafting are multiple. Carotid scanning in patients with neurologic symptoms or carotid bruits can identify patients at increased risk. Patients with carotid occlusion are at high risk for stroke on the occluded side. (J T HORAC C ARDIOVASC S URG 1996;112:1250-9)

MR angiography of the renal arteries

MR angiography (MRA) has shown considerable promise as a nonivasive tool in the evaluation of renal vascular morphology. There are two fundamental approaches to MRA of the renal arteries: time of flight and phase contrast imaging. Recently, three-dimensional, gradient-echo, gadolinium-enhanced MRA using breath-hold techniques also has been introduced. These techniques have made MRA of the renal arteries a very promising, noninvasive tool in the detection of main renal artery stenosis, with sensitivities between 90% and 100%. MRA is used most often in the evaluation of renal arteries of patients with abdominal aortic aneurysms or allergies to iodinated contrast media, or when other noninvasive screening examinations have been inconclusive. One of the most helpful and unique applications of MRA is in patients who have accelerating hypertension and accelerating renal insufficiency. These patients often have preexisting unilateral renal artery stenosis with a new contralateral renal artery stenosis. Conventional angiography is risky in these patients because of possible contrast nephropathy. MRA, in such cases, is very helpful for differentiating between bilateral renal artery stenosis and end-stage nephrosclerosis.

Carotid duplex overestimation of stenosis due to severe contralateral disease

In the quest to use carotid duplex to assess carotid occlusive disease, it has been reported that the current velocity criteria to calculate stenosis tends to overestimate the severity when there is a contralateral highly stenotic or occluded carotid artery. Patient records were reviewed for 592 consecutive carotid endarterectomies performed from 1987 to 1994. Preoperative and postoperative duplex scan results were compared in a subset of patients in whom duplex overestimated the degree of stenosis, as compared to preoperative angiography. A total of 146 patients were identified in whom duplex overestimated the degree of stenosis contralateral to a high grade stenosis or an occlusion. Of 76 arteries, 18 (23.7%) contralateral to an occluded artery were overestimated by duplex, and 128 (27.0%) of 474 arteries contralateral to a high grade stenosis were overestimated. Following endarterectomy 44 (51.8%) of 128 nonoperated contralateral stenoses decreased by at least one duplex category. The average peak systolic frequency (PSF) decreased by 1175 Hz (P = 0.0018), and the average end diastolic frequency (EDF) decreased by 475 Hz (P = 0.011). Patients with high grade stenosis have a significant decrease in PSF and EDF in the unoperated carotid after endarterectomy, supporting a compensatory flow phenomenon. This often results in a decrease in the postoperative duplex defined stenosis by at least one category. The clinical significance of these findings is of increasing importance as carotid surgery is being performed more frequently without angiography.

Is routine carotid ultrasound surveillance after carotid endarterectomy worthwhile?

Periodic ultrasound studies are routinely performed after carotid endarterectomy with the aim of detecting recurrent stenosis or progression of contralateral disease. The frequency with which these studies should be performed and their clinical utility is at present unclear. Our experience with ultrasound surveillance after carotid endarterectomy was reviewed. We performed a retrospective analysis of our carotid registry as a follow-up on patients who had undergone primary endarterectomy between 1982 and 1995. The database was searched for events referable to the contralateral carotid artery including incidence of contralateral endarterectomy, progression of contralateral stenosis, and development of new neurologic symptoms. Data was analyzed by life-table methodology. A total of 562 patients underwent 660 endarterectomies during the study interval with a postoperative stroke rate of 3.6% and a mortality of 1.1%. Of these, 496 patients had data available on the contralateral artery. There were 384 patent, nonoperated contralateral arteries available for long-term clinical follow-up, of which 276 had serial Doppler examinations. At the time of initial presentation, 30% of patients (141 cases) had greater than 50% diameter stenosis in the contralateral artery including 45 occlusions. There were 67 contralateral endarterectomies performed within 6 months of the original surgery. An additional 15 endarterectomies were performed within 24 months of the original surgery and only 16 subsequent endarterectomies were performed up to the 8-year follow-up. Progression of contralateral stenosis from less than to greater than 50% occurred in 10.1% of the patient population. The rate of disease progression was 5.1% at 3 years, 17.8% at 5 years, and 30% at 7 years. Stroke-free survival in patients without progression was 94.7% at 3 years and 93.3% at 5 years. Significant contralateral disease occurs in about one third of patients, most of whom are candidates for early contralateral endarterectomy. In patients who present with minimal contralateral disease, the incidence of progression is low over time. Follow-up duplex examinations on a biennial schedule is sufficient to detect clinically significant disease progression in these patients.

Outcome of Patients with Symptomless Carotid Bruits: A Prospective Study

Knowledge of the natural history of symptomless carotid artery disease is important in determining the best preventative treatment for symptom-free patients. To document the progression of carotid artery disease and the clinical course of a symptomless population, 336 patients with symptom-free carotid bruits were prospectively followed up initially with oculoplethysmography and subsequently with duplex scanning. During a mean follow-up of 4.87 years, eight patients (2.4%) suffered a stroke. Thirtyseven (11.0%) experienced transient ischaemic attacks (TIAs). The cumulative event rate (TIA plus stroke) was 13.4% (45/336). The annual event rates were 0.48% for stroke. 2.26% for TIA and 2.75% for all ischaemic events. In a subgroup of 69 high-grade carotid stenoses (80–99%), 31 carotid endarterectomies were performed before the development of a TIA or stroke and 21 after the development of symptoms, while 17 lesions were followed-up non-operatively. The total event rate (TIA and stroke) was significantly greater in the non-operated compared with the operated arteries (51.0% versus 6.4% at 5 years, P= 0.0034). However, most of the events which occurred in the non-operated group were TIAs (85.7%) rather than stroke. There was no difference in the death rate of the two groups (P&gt; 0.05). Review of serial duplex studies performed on 540 carotid arteries revealed that 382 arteries (70.7%) remained unchanged and 158 (29.3%) showed disease progression. Forty-four of the 540 arteries became symptomatic (TIA or stroke). In 29 of the 44, the event occurred without any change in diameter of the artery, while in 15 there was a change of at least one category greater stenosis. In 39 patients, the stenosis was at least 40% and in five the stenosis was under 40%. Nine events occurred in the patients with severe contralateral carotid stenoses (&gt; 60%). The incidence of TIA (32.2%), stroke (6.8%) and death (18.6%) was higher in patients with internal carotid artery stenoses in excess of 80% than in those with lesions between 0 and 79% stenosis (P&lt; 0.0001, P= 0.0367 and P= 0.0236, respectively). In this study the incidence of cerebrovascular events was higher in patients with high-grade internal carotid artery disease, and the preservation of neurological status in patients with symptomless high-grade carotid artery stenosis was improved by carotid endarterectomy, although the overall mortality remained unchanged.

Outcome of patients with symptomless carotid bruits: a prospective study

Knowledge of the natural history of symptomless carotid artery disease is important in determining the best preventative treatment for symptom-free patients. To document the progression of carotid artery disease and the clinical course of a symptomless population, 336 patients with symptom-free carotid bruits were prospectively followed up initially with oculoplethysmography and subsequently with duplex scanning. During a mean follow-up of 4.87 years, eight patients (2.4%) suffered a stroke. Thirtyseven (11.0%) experienced transient ischaemic attacks (TIAs). The cumulative event rate (TIA plus stroke) was 13.4% ( 45 336 ). The annual event rates were 0.48% for stroke, 2.26% for TIA and 2.75% for all ischaemic events. In a subgroup of 69 high-grade carotid stenoses (80–99%), 31 carotid endarterectomies were performed before the development of a TIA or stroke and 21 after the development of symptoms, while 17 lesions were followed-up non-operatively. The total event rate (TIA and stroke) was significantly greater in the non-operated compared with the operated arteries (51.0% versus 6.4% at 5 years, P = 0.0034). However, most of the events which occurred in the non-operated group were TIAs (85.7%) rather than stroke. There was no difference in the death rate of the two groups ( P>0.05). Review of serial duplex studies performed on 540 carotid arteries revealed that 382 arteries (70.7%) remained unchanged and 158 (29.3%) showed disease progression. Forty-four of the 540 arteries became symptomatic (TIA or stroke). In 29 of the 44, the event occurred without any change in diameter of the artery, while in 15 there was a change of at least one category greater stenosis. In 39 patients, the stenosis was at least 40% and in five the stenosis was under 40%. Nine events occurred in the patients with severe contralateral carotid stenoses (>60%). The incidence of TIA (32.2%), stroke (6.8%) and death (18.6%) was higher in patients with internal carotid artery stenoses in excess of 80% than in those with lesions between 0 and 79% stenosis ( P < 0.0001, P = 0.0367 and P = 0.0236, respectively). In this study the incidence of cerebrovascular events was higher in patients with high-grade internal carotid artery disease, and the preservation of neurological status in patients with symptomless high-grade carotid artery stenosis was improved by carotid endarterectomy, although the overall mortality remained unchanged.

Carotid endarterectomy without a shunt for symptomatic lesions associated with contralateral severe stensosis or occlusion

The purpose of this study was to assess the adequacy of thiopental protection against ischemic cerebral damage in patients undergoing carotid endarterectomy for symptomatic stenosis greater than 70% in association with contralateral stenosis greater than 70% or contralateral occlusion. All patients (n=259) with severe bilateral carotid disease who underwent carotid endarterectomy for symptomatic stenosis greater than 70% were extracted from the database of an ongoing prospective carotid surgery study. Large-dose thiopental sodium without shunting was used for cerebral protection during endarterectomy. Asymmetric electroencephalogram changes during the operation, carotid occlusion time, stroke onset, and neuropathologic outcomes were analyzed. Three contralateral strokes occurred in the series, producing a cerebral morbidity/mortality rate of 1.2% (major 0.4%, minor 0.8%). Transient morbidity was 1.9% made of two reversible ischemic neurologic deficits and three transient ischemic attacks. New asymmetric electroencephalography changes were seen in 49 (19% patients, one of whom had transient deficit. Average occlusion time was 35 minutes. All strokes occurred within 24 hours of the procedure. Patients with previous stroke and and systemic hypertension seemed at greatest risk, and the contralateral hemisphere was the area at greatest risk. All transient deficits were ipsilateral and related to technical complications rather failed protection. Thiopental cerebral protection eliminates strokes caused by complications of shunting, prevents ischemic stroke during carotid occlusion for periods up to 67 minutes (average 35 minutes), allows meticulous management of the operative site, may modify or minimize clinical neurologic deficit, and in our experience has rendered intraluminal shunting obsolete.

Evolution of different therapeutic strategies in the treatment of cranial dural arteriovenous fistulas--report of 30 cases.

30 cases of cranial dural arteriovenous fistuals, treated between 1983 and 1992, are reported. Twelve presented with an aggressive clinical course including intracranial haemorrhage, progredient neurological deficit, medically intractable seizures, and cerebellar symptoms. The other 18 patients had a more benign clinical presentation with audible bruit, exophthalmus, chemosis, and cranial nerve dysfunction. One of the latter had symptoms of pseudotumour cerebri due to sinus occlusion with contralateral sinus stenosis. The most common location was at the transverse sinus, followed by the cavemous sinus, the tentorial ring, and the orbita. Four vessel angiography verified the diagnosis and demonstrated all fistulas, mainly supplied by branches of the external carotid artery. 16 of 18 benign lesions were treated by endovascular therapy alone. Two recent patients received adjuvant stereotactic radiosurgery. Among these 18 patients 2 remained untreated, one because of spontaneous fistula thrombosis prior to therapy and one because of poor medical condition. 12 of 16 treated benign dural fistulas were partially occluded. In 6 of them spontaneous fistula thrombosis occurred during the following months. Total endovascular obliteration was achieved in the remaining 4 patients. 7 of 12 aggressive fistulas were embolized only, one of them having additional radiosurgery. Two of them were totally obliterated and five partially. Surgery was performed in the remaining 5 aggressive fistulas. Complete microsurgical excision was achieved in 2 and partial in further two, who presented initially with a life-threatening intracerebral clot. In one early case ligation of the external carotid artery was done, which is now obsolete. Over all 20 of 28 treated patients became asymptomatic or improved clinically. 3 of the remaining 8 patients were unchanged, two deteriorated despite therapy, and 3 worsened after therapy. All of the latter complications occurred early in our series due to thromboembolic events during the procedure. One surgical patient suffered from a new facial nerve palsy postoperatively. Follow up time in all treated patients was between 1 and 139 months with a mean of 48,3 months.

Vasomotor reactivity and pattern of collateral blood flow in severe occlusive carotid artery disease.

The compromise of cerebrovascular autoregulation in severe occlusive carotid artery disease depends on the functional capacity of collateral pathways. In previous reports correlating hemodynamic disturbances with collateral pathways, collateral blood supply was often evaluated by invasive cerebral angiography. In this study noninvasive transcranial Doppler ultrasound was used to determine both collateral pathways and vasomotor reactivity. With the use of blood flow direction, compression tests, and evident side-to-side asymmetries of blood velocities, the collateral supply through the anterior and posterior communicating arteries, the ophthalmic artery, and leptomeningeal anastomoses was evaluated by transcranial Doppler ultrasound in 48 patients (42 men, 6 women; mean +/- SD age, 59 +/- 9 years) with occlusion (n = 36) or stenosis of more than 90% (n = 12) of one internal carotid artery. Ipsilateral vasomotor reactivity was determined by the percent increase of middle cerebral artery mean blood velocity with the use of (1) the breath-holding maneuver and (2) acetazolamide (1 g IV) as vasodilatory stimulus. Additional stenoses (50% to < 90%) of the contralateral internal carotid artery were present in 20 of the 48 patients. Vasomotor reactivity was not affected by the presence of a contralateral internal carotid artery stenosis. Both vasodilatory stimuli similarly indicated poor vasomotor reactivity when an ophthalmic or a leptomeningeal pathway accompanied an anterior communicating artery pathway compared with a lone anterior communicating artery pathway (P < .05). The acetazolamide challenge indicated significantly better preserved vasomotor reactivity when blood supply was provided through a lone anterior communicating artery pathway (66 +/- 30%) than through an anterior and posterior communicating artery pathway (33 +/- 20%, P < .05), whereas the breathholding method failed to show such a difference. The presence of an ophthalmic artery pathway may provide the first evidence of disturbed vasomotor reactivity. The use of cerebral angiography to evaluate collateral pathways must be considered carefully since transcranial Doppler ultrasound is a reliable noninvasive alternative.

Contralateral external carotid-to-external carotid artery (half-collar) saphenous vein graft for common carotid artery occlusion

In a patient having common carotid artery occlusion complicated with contralateral internal carotid artery stenosis, a saphenous vein bypass graft was performed from the contralateral external carotid artery to the ipsilateral external carotid artery simultaneously with contralateral carotid endarterectomy. The bypass was patent 1 year later and the patient was free from fainting spells. Among a number of the reconstructive surgical procedures, this “half-collar bypass” can be placed adequately in the subcutaneous soft tissue so that head or mandibular movement does not displace or compress the graft. Intraoperative hemodynamic measurements were considered useful in determining surgical options.

Endovascular Treatment of Urgent Carotid Occlusion

Emergency revascularization of acute carotid artery occlusion is still controversial. We treated 15 patients (13 men and two women, mean age of 67.3 years) with acute atherosclerotic carotid occlusion by endovascular procedures and evaluated the usefulness of this treatment. All of the patients were evaluated with emergency MRI and MRA before treatment. Intracranial tandem arterial occlusion due to distal embolism was observed in nine patients, and contralateral carotid stenosis (&gt;70%) was observed in seven. The mean NIHSS score of the patients was 15.4±7.4 (mean±SD) before treatment. Treatment modality included local intraarterial fibrinolysis (LIF), percutaneous transluminal angioplasty (PTA), and carotid artery stenting (CAS). A protective balloon was successfully placed in the distal carotid artery through the plaque before recanalization in seven patients. Three patients were treated with LIF+PTA, five with PTA+CAS, six with LIF+PTA+CAS, and one with PTA only. Successful recanalization of the carotid artery was obtained in 14 of the 15 patients, and distal tandem middle cerebral artery occlusion was also successfully recanalized in eight of the nine patients. GOS was four or five in eight patients (good outcome group) and 1–3 in seven patients (poor outcome group). Mean NIHSS score of the 15 patients was (6.9 ± 7.4) after treatment. Preoperative NIHSS score (10.3 ± 7.4) in the good outcome group was significantly lower than that (21.3 ± 5.4) in the poor outcome group. The protective balloon technique, PTA with stenting, seems to be useful for acute revascularization of urgent carotid occlusion. Simultaneous treatment of the intracranial tandem occlusive lesion is essential to achieve good clini-cal results. Patients with acute carotid occlusion with NIHSS scores of less than 16 could be good candidates for this advanced treatment.

Effect of contralateral severe stenosis or carotid occlusion on duplex criteria of ipsilateral stenoses: Comparative study of various duplex parameters

This study compares the accuracy of various duplex parameters in grading ipsilateral carotid stenoses in patients with contralateral severe stenoses or occlusion. Four duplex criteria were correlated to arteriography in 356 carotid arteries in blind fashion: (1) standard criteria: a peak systolic frequency (PSF) of the internal carotid artery (ICA) of > or = 4 kHz was used to diagnose > or = 50% stenosis; (2) new criteria: a PSF of the ICA of > or = 4.5 kHz was used; (3) Fujitani criteria: a PSF of the ICA of > 4.5 kHz and an end-diastolic frequency of < 5.0 kHz was used; (4) internal carotid/common carotid artery (ICA/CCA) PSF ratio of > or = 1.5 was used. The standard method overestimated 56 (16%) of 356 stenoses in contrast to 3% for the new method (p < 0.001), and this effect was most evident in the 50% to < 80% stenosis category (30%). The Fujitani method underestimated 97 (27%) of 356 stenoses, and the ICA/CCA ratio overestimated stenoses in 77 (22%) of 356. The overall exact correlation was 94%, 82%, 70%, and 75% for the new, standard, Fujitani, and ICA/CCA ratio, respectively. The kappa statistic and corresponding confidence intervals for the new method (kappa = 0.923, +/- 0.016) are significantly higher (p < 0.001) than those for the standard method (kappa = 0.760, +/- 0.027), the Fujitani method (kappa = 0.608, +/- 0.031), and the ICA/CCA ratio method (kappa = 0.642, +/- 0.051). The overall accuracy in diagnosing > or = 50% ipsilateral stenosis in the whole series was 85% for the standard method, 97% for the new method, 95% for the Fujitani method, and 81% for the ICA/CCA ratio. The new method was superior to the standard and ICA/CCA ratio methods (p < 0.001) and the Fujitani method (p = 0.024). The presence of significant contralateral stenosis (> or = 50%) can lead to overestimation of ipsilateral stenosis if the standard criteria are used; however, this problem can be avoided by using a PSF of the ICA of > or = 4.5 kHz for the diagnosis of > or = 50% stenosis.

Albuminuria predicts renal functional outcome after intervention in atheromatous renovascular disease.

Atheromatous renovascular disease is increasingly recognized as a cause of renal failure; however, the benefit of intervention on renal function outcome cannot be clearly anticipated. To identify reliable predictor(s) of renal functional outcome after revascularization in patients with atheromatous renovascular disease. The effect of percutaneous transluminal renal angioplasty (n = 5) or surgery (n = 18) on glomerular filtration rate ([99mTc]-diethylene triaminopenta-acetic acid clearance) and renal haemodynamics was prospectively assessed in 23 patients with atheromatous renovascular disease (unilateral occlusion in five, unilateral stenosis in four, stenosis of a single kidney in five, unilateral occlusion associated with contralateral stenosis in six, bilateral stenosis in three). Renal function was altered in 18 patients. At early follow-up study (5 +/- 1 months) after intervention, glomerular filtration rate improved (i.e. increased by more than 15%) in six patients, deteriorated in five and remained unchanged in 12 patients. The change in glomerular filtration rate associated with intervention was inversely correlated with the pre-intervention level of urinary albumin excretion and positively with the change in effective renal plasma flow after intervention. Stepwise regression analysis showed that pre-intervention urinary albumin excretion was the only predictor of the glomerular filtration rate response to intervention. At late follow-up study (32 +/- 6 months, n = 13), glomerular filtration rate was stable compared with early follow-up determination in non-proteinuric patients whereas it had deteriorated further in proteinuric patients. In patients with atheromatous renovascular disease, albuminuria may be considered as a marker of pre-existing intra-renal vascular and glomerular damage and a reliable predictor of renal functional outcome after intervention.

The influence of contralateral carotid stenosis and occlusion on cerebral oxygen saturation during carotid artery surgery

To study the effect of contralateral carotid stenosis on oxygen saturation (CsO2) of both cerebral hemispheres monitored by reflective near-infrared spectroscopy (NIRS) during carotid surgery. NIRS was compared to ipsilateral transcranial Doppler ultrasonography (TCD) of the middle cerebral artery and jugular bulb venous oxygen saturation (JvSO2) in 54 patients undergoing carotid endarterectomy. Median operated side and contralateral CsO2 were 68(54-88)% and 69(55-85)% before carotid clamping falling to 63(44-80)% and 69(55-84)% respectively on clamping the carotid (p < 0.0001 and p = NS). JvSO2 fell from 78(38-98)% to 72(30-97)% on carotid clamping with a percentage fall in peak TCD of -28(0 to -100)% (p < 0.0001). Patients with a contralateral carotid artery occlusion experienced falls in ipsi and contralateral CsO2 of -8(-4 to -10)% and -3(2 to -7)% compared to -4(0 to -14)% and 0(-5 to 4)% in those with a lesser stenosis (p < 0.05). On declamping, median ipsilateral and contralateral CsO2 rose from 65(46-82)% and 67(52-87)% to 68(53-84)% respectively (p < 0.0001 and p = NS). JvSO2 increased from 75(33-95)% to 79(42-95)% (p < 0.0001) with an increase in median peak TCD of 35(-34 to 506)%. The greatest changes in CsO2 occurred in the operated side cerebral hemispheres in those with a contralateral carotid artery occlusion. However, a contralateral carotid artery occlusion does not reliably predict the need for a shunt and cerebral monitoring remains essential; although is only required on the operated side.

Ultrasonographic evaluation of multicystic dysplastic kidney.

Eleven cases of multicystic dysplastic kidney (MCDK) in children were diagnosed over an 11 year period. All underwent postnatal ultrasound (US) studies. Four different patterns of MCDK were recognized: (1) Six cases presented with the classic sonogram of multicystic components. (2) Three cases had hydronephrotic form; correct diagnosis between hydronephrotic form of MCDK and hydronephrosis was difficult as there was a medially-located, large, lobulated cyst and there was connection between the large cyst and neighboring small cysts. (3) One case initially presented with normal renal sonogram but a small cyst appeared on follow up sonogram and there was also decreased renal size and increased echogenecity. (4) One case had only two moderate-sized cysts but no identifiable renal parenchyma. Two cases had follow-up US examination and one dysplastic kidney decreased in renal size on follow-up sonogram. Intravenous urography and radionuclide study revealed both these dysplastic kidneys to be nonfunctioning. Nine children had surgical resection of the diseased kidneys. Contralateral renal anomalies were detected in five children, which included ureteropelvic junction stenosis, ureterovesical junction stenosis, distal ureteral stenosis and polycystic kidney disease. Two of three hydronephrotic forms of MCDK had contralateral ureteral stenosis. Two of six classic forms of MCDK had contralateral ureteral stenosis. The proportion of contralateral ureteral stenosis was higher in the group of hydronephrotic forms of MCDK. Ultrasonography is beneficial for conclusive diagnosis of MCDK; however, a differential diagnosis of simple hydronephrosis needs to be considered.

Treatment of Aneurysms of the Internal Carotid Artery by Intravascular Balloon Occlusion: Long-term Follow-up of 58 Patients

Long-term evaluation of patients with aneurysms of the internal carotid artery (ICA) treated by intravascular balloon occlusion has not been reported. From 1977 to 1992, 58 patients (age 14 to 81 years) with ICA aneurysms were treated at our institution by this technique. The aneurysms included 40 intracavernous carotid, 5 petrous carotid, 3 cervical carotid, and 10 ophthalmic segment aneurysms. Presenting symptoms were caused by mass effect in 45 patients, transient ischemia or cerebral infarction as a result of emboli in 6, subarachnoid hemorrhage in 4, and epistaxis in 3. Preoperative temporary balloon occlusion of the ICA combined with cerebral blood flow monitoring and induced hypotension were used to determine tolerance for occlusion. Two patients not tolerating test occlusion required an extracranial-intracranial bypass procedure, and another patient underwent extracranial-intracranial bypass prior to test occlusion because of contralateral ICA stenosis. In 55 patients, aneurysms were excluded from the circulation by either occluding the proximal ICA or trapping the aneurysm neck. In three patients, the aneurysm was directly obliterated with intravascular balloons with preservation of the parent ICA. Three patients died during treatment, one from subarachnoid hemorrhage and two from cerebral infarction. Mean follow-up was 76 months (range, 6 months to 15 years). Six patients who developed transient ischemia caused by emboli responded to volume expansion and anticoagulation treatment. Two patients developed a delayed infarction, and one patient developed aneurysm enlargement that required surgical clipping and obliteration. (ABSTRACT TRUNCATED AT 250 WORDS)

頭蓋内外の多発性の閉塞性病変に対する手術療法

Surgical treatment for multiple occlusive lesions of the intracranial and extracranial arteries are still controversial. We report 2 patients treated with successful results by multistaged surgical procedures. Case 1, a 65-year-old man, complained of transient ischemic attacks of aphasia and right hemiparesis with vertebrobasilar insufficiency syndrome. He had a past history of hypertrophic cardiomyopathy. His angiograms revealed multiple intra- and extracranial occlusive lesions (the left subclavian artery occlusion and bilateral internal carotid lesions). A subclavian-subclavian bypass following the right carotid endarterectomy (CEA) was performed using external shunt from the subclavian bypass graft end during CEA. However, transient ischemic attacks continued after the first operation and single photon emission tomography still demonstrated the left hemispheric ischemia. The left STA-MCA anastomosis was then performed 7 months later. Postoperative course was uneventful and recurrent episode of TIAs disappeared.Case 2, a 56-year-old man, suffered from minor stroke of right hemiparesis and acute myocardial infarction simultaneously. Angiogram showed an unruptured aneurysm of the middle cerebral artery and severe stenosis of the right internal carotid artery with contralateral middle cerebral artery stenosis. The aneurysm was clipped prior to CEA of the ipsilateral internal carotid artery stenosis. As the next procedure, CEA on the right side and the left STA-MCA anastomosis was performed simultaneously.In the cases of extra- and intracranial tandem occlusive lesions, the proximal severe lesion should be treated surgically initially. During the bypass or CEA procedure, extra care should be taken in these cases to protect the brain from ischemia perioperatively. Such patients may often be suffering from various heart diseases. The selection of surgical procedure should be carefully considered in cooperation with a cardiologist.

Patients with low stump pressure and possible pressure fall in the middle cerebral artery during carotid surgery may be identified preoperatively by transcranial Doppler.

Although it has now been established that surgery is the best way to treat patients with symptomatic tight carotid stenosis, the fact remains that perioperative risks are not negligible. Patients with significant contralateral stenosis and/or no collateral flow capacity through the anterior communicating artery are likely to be at higher risk during surgery. We examined a series of 52 patients pre- and postoperatively with transcranial Doppler (TCD) and compared the results to perioperative stump pressures. Our intention was to find out whether the results of the TCD examination of the circle of Willis could be correlated to the perioperative stump pressures, and whether TCD gives reliable information about the collateral flow. We found relatively high stump pressures in patients with potential function of any communicating artery, and in the group with no collateral function most patients had low stump pressures. We also found that preoperative flow velocity fall in the middle cerebral artery (MCA) on compression of the ipsilateral internal carotid artery correlated with perioperative stump-pressure indices. However, we were unable to predict stump pressures in individual patients by flow velocity measurements in the MCA preoperatively.