Vascular surgery without arteriography: use of Duplex ultrasound

Neurocognitive changes after eversion carotid endarterectomy under local anesthesia

BACKGROUND

The effects of carotid endarterectomy (CEA) on cognitive function have yet to be fully elucidated. The aim of our study was to administer a battery of cognitive tests to identify any cognitive changes occurring in a consecutive series of patients who underwent CEA using the eversion technique under local anesthesia.

METHODS

This prospective study was designed to analyze a consecutive series of patients undergoing eversion CEA under local anesthesia for significant carotid stenosis at our vascular surgery unit over a period of 6 months. Patients underwent tests to rule-out those who already had cognitive impairments or states of depression/anxiety capable of interfering with cognitive testing outcomes. Patients then completed a battery of 10 neurocognitive tests preoperatively and again 30 days and 4 months after surgery to assess the functions of both cerebral hemispheres as thoroughly as possible.

RESULTS

Of the 48 patients initially considered for our study, 39 completed the follow-up. They were 71.4 ± 8.2 (mean ± SD) years of age; 30 were men and 9 were women. Six were symptomatic for carotid stenosis and 33 were asymptomatic. All patients were examined by a neurologist and underwent pre- and postoperative nuclear MRI or CT scan of the brain to identify any cerebral ischemia potentially correlated with the surgical procedure. In all cases, the cognitive test findings tended to improve postoperatively; this improvement was statistically significant in 7 tests. Post-hoc analysis confirmed an improvement between the pre- and postoperative test results. Among the different variables considered, only age <75 years seems to have influenced cognitive improvement.

CONCLUSIONS

The effects on cognitive function of carotid stenosis, particularly CEA, is still a much debated issue. The data reported in the literature vary considerably, preventing any final conclusions from being drawn. The mechanisms capable of inducing changes in cognitive status after CEA have yet to be precisely clarified. In our study, a suitable battery of tests were used to analyze the trend of cognitive function correlating with eversion CEA under local anesthesia. Our results demonstrate substantially improved cognitive function after CEA, which was statistically significant in 7 of 10 tests. We surmise that the CEA procedure, per se, can help to protect patients against cognitive deterioration, especially in those <75 years of age.

Multicentric retrospective study of endovascular treatment for restenosis after open carotid surgery

OBJECTIVES

To analyse perioperative and midterm outcomes of carotid artery stenting (CAS) for symptomatic >50% and asymptomatic >70% restenosis after open carotid surgery (OCS).

DESIGN

A multicentric retrospective study.

METHODS

Outcome measures 30-day death, neurologic and anatomic (thrombosis, restenosis) events. Univariant and multivariant logistic regression analyses were performed to identify predictive factors for neurologic and anatomic events.

RESULTS

A total of 249 patients with a mean age of 69 years (range, 45-88) were treated for asymptomatic (86%) or symptomatic (14%) restenosis. The 30-day combined operative mortality and stroke morbidity was 2.8% in asymptomatic patients and 2.9% in symptomatic patients. Events during follow-up (mean duration, 29 months) included stroke in four cases, TIA in two, stent thrombosis in four and restenosis in 21. Kaplan-Meier estimates of overall survival, neurologic-event-free survival, anatomic-event-free survival and reintervention-free survival were 95.4%, 94.7%, 96.7% and 99.5%, respectively, at 1 year and 80.3%, 93.8%, 85.1% and 96%, respectively, at 4 years. Multivariant analysis showed that statin use was correlated with a lower risk of anatomic events (odds ratio (OR) = 0.15 (95% confidence interval (CI) 0.03-0.68), p = 0.01) and that bypass was associated with a higher risk of anatomic events than endarterectomy (OR = 5.0 (95% CI 1.6-16.6), p = 0.009).

CONCLUSION

CAS is a feasible therapeutic alternative to OCS for carotid restenosis with acceptable risks in the perioperative period. Restenosis rate may be higher in patients treated after bypass.

Detecting vascular injury in lower-extremity orthopedic trauma: the role of CT angiography

As a screening tool, CT angiography has excellent sensitivity and specificity combined with fewer complications compared to conventional arteriography.

Open bypass and endoluminal therapy: complementary techniques for revascularization in diabetic patients with critical limb ischaemia

The use of endovascular therapy (EVT) for lower extremity atherosclerosis is markedly increasing while open surgical bypass is in decline. The results of EVT for critical limb ischaemia (CLI) are difficult to evaluate, especially for patients with diabetes. To date, only one randomized, prospective trial has been published comparing EVT with open bypass for CLI. Although early costs and outcomes were equivalent or superior for EVT, after 2 years, surgery was associated with a significantly reduced risk of future amputation and death.Approximately, 40-50% of diabetic patients with CLI can be initially treated with EVT. Patients with Trans-Atlantic Inter-Society Consensus (TASC) A and B lesions should be treated endoluminally. EVT should be used with caution in patients with TASC C and D lesions; however, in selected patients, particularly if vein conduit is lacking and life expectancy is short, EVT is not unreasonable. For low-to-moderate risk patients with TASC C or D lesions, extensive tibial disease, and suitable vein conduit, surgical bypass remains the best limb preservation option. The primary therapeutic goals are relief of rest pain, healing of ischaemic lesions, and maintenance of functional status. Haemodynamic assessment is critical following both open and EVT for CLI and aids in determining the need for further revascularization; additional interventions are required in 20-30% of CLI patients depending on the degree of ischaemia, anatomical disease extent, and mode of initial therapy. At the University of Arizona, we currently recommend that TASC A and B CLI patients undergo EVT first. TASC C and D patients should undergo bypass unless available conduit is poor, surgical risk is prohibitive, or life expectancy is limited. CLI is a serious end-of-life condition given the sobering realization that only 50-55% of CLI patients are alive with an intact limb 5 years after initial presentation.

Critical limb ischemia

Critical limb ischemia (CLI) is the most severe manifestation of peripheral artery disease (PAD). Without timely recognition, appropriate diagnosis, and revascularization, patients with CLI are at risk for amputation or potentially fatal complications. The past decade has seen substantial growth in endovascular CLI therapies and options now exist for treating long-segment lower-extremity arterial occlusive disease, but surgical bypass may yield more durable results. Patients who are younger, more active, and at low risk for surgery may have better outcomes with an operation. Surgical treatment is also indicated for failures of endovascular therapy, which may include early technical failures or later occlusion after placement of stents or other interventions.

Carotid stenosis measurement on colour Doppler ultrasound: Agreement of ECST, NASCET and CCA methods applied to ultrasound with intra-arterial angiographic stenosis measurement

PURPOSE

Carotid stenosis is usually determined on Doppler ultrasound from velocity readings. We wondered if angiography-style stenosis measurements applied to ultrasound images improved accuracy over velocity readings alone, and if so, which measure correlated best with angiography.

MATERIALS AND METHODS

We studied prospectively patients undergoing colour Doppler ultrasound (CDU) for TIA or minor stroke. Those with 50%+ symptomatic internal carotid artery (ICA) stenosis had intra-arterial angiography (IAA). We measured peak systolic ICA velocity, and from the ultrasound image, the minimal residual lumen, the original lumen (ECST), ICA diameter distal (NASCET) and CCA diameter proximal (CCA method) to the stenosis. The IAAs were measured by ECST, NASCET and CCA methods also, blind to CDU.

RESULTS

Amongst 164 patients (328 arteries), on CDU the ECST, NASCET and CCA stenosis measures were similarly related to each other (ECST = 0.54 NASCET + 46) as on IAA (ECST = 0.6 NASCET + 40). Agreement between CDU- and IAA-measured stenosis was similar for ECST (r = 0.51), and CCA (r = 0.48) methods, and slightly worse for NASCET (r = 0.41). Adding IAA-style stenosis to the peak systolic ICA velocity did not improve agreement with IAA over peak systolic velocity alone.

CONCLUSION

Angiography-style stenosis measures have similar inter-relationships when applied to CDU, but do not improve accuracy of ultrasound over peak systolic ICA velocity alone.

Systematic review of randomized controlled trials of patch angioplasty versus primary closure and different types of patch materials during carotid endarterectomy

BACKGROUND

Patch angioplasty during carotid endarterectomy (CEA) may reduce the risk for perioperative or late carotid artery recurrent stenosis and subsequent ischemic stroke. We performed a systematic review of randomized controlled trials to assess the effect of routine or selective carotid patch angioplasty compared with CEA with primary closure, and the effect of different materials used for carotid patch angioplasty.

METHODS

Randomized trials were included if they compared carotid patch angioplasty with primary closure in any patients undergoing CEA or use of one type of carotid patch with another.

RESULTS

Thirteen eligible randomized trials were identified. Seven trials involving 1281 operations compared primary closure with routine patch closure, and 8 trials with 1480 operations compared different patch materials (2 studies compared both). Patch angioplasty was associated with a reduction in risk for stroke of any type (P = .004), ipsilateral stroke (P = .001), and stroke or death during both the perioperative period (P = .007) and long-term follow-up (P = .004). Patching was also associated with reduced risk for perioperative arterial occlusion (P = .0001) and decreased recurrent stenosis during long-term follow-up (P < .0001). Seven trials that compared different patch types showed no difference in the risk for stroke, death, or arterial recurrent stenosis either perioperatively or at 1-year follow-up. One study of 180 patients (200 arteries) compared collagen-impregnated Dacron (Hemashield) patches with polytetrafluoroethylene patches. There was a significant increase in risk for stroke (P = .02), combined stroke and transient ischemic attack (P = .03), and recurrent stenosis (P = .01) at 30 days, and an increased risk for late recurrent stenosis greater than 50% (P < .001) associated with Dacron compared with polytetrafluoroethylene.

CONCLUSIONS

Carotid patch angioplasty decreases the risk for perioperative death or stroke, and long-term risk for ipsilateral ischemic stroke. More data are required to establish differences between various patch materials.

Carotid Endarterectomy: Experience in 5425 Cases

From 1992 to December 2002, 3967 patients (2619 males; 1348 females) with a mean age of 68.4A years (range 32-92) underwent 5425 carotid endarterectomy (CE) procedures at our institute. Neurological history was positive for stroke in 1130 cases (21%) and for transient ischemic attack (TIA) in 2121 cases (39%). In 2174 cases (40%) patients were neurologically asymptomatic or presented nonspecific symptoms. Our current clinical protocol has been designed to optimize resources and reduce complications. Some of the major features, along with the respective percentages in this series, are as follows. Duplex scanning was performed at a validated laboratory as the principal preoperative exam (86.9%). Locoregional anesthesia and neurological monitoring were performed during carotid cross-clamping (96.3%). Selective shunting was carried out with a Javid shunt (10.7%). The choice of surgical technique was made according to carotid anatomy and cerebral tolerance of cross-clamping. Those used were a standard technique (now abandoned, 12.1%), synthetic patching (46.4%), and eversion endarterectomy (41.5%). Intraoperative completion arteriography was routinely performed for eversion endarterectomy and only in dubious cases with other techniques. The option of staying in an postoperative intensive care unit (ICU) was available (selective use, 2%). In uncomplicated cases, early discharge (after 1.5 postoperative days) was considered safe. The overall perioperative mortality was 0.37% (20/5425). Causes of death were myocardial infarction in seven cases, ischemic stroke in six cases, hemorrhagic stroke in five cases, respiratory failure caused by cervical hematoma in one case, and wound infection in one case. Perioperative neurological morbidity was 1.31% (71/5425); there were 43 major and 28 minor strokes. In conclusion, CE is effective for stroke prevention when there is significant symptomatic and asymptomatic carotid stenosis, as low mortality and morbidity may be achieved in an experienced center. At our institute, the reduction of costs did not have negative consequences on the quality of the surgical care.

Gadolinium-enhanced MR Angiography as First-Line Preoperative Imaging in High-Risk Patients with Lower Limb Ischemia

PURPOSE

To assess the clinical relevance of gadolinium-enhanced MR angiography (Gd-MRA) as the first-line angiographic examination for planning lower limb revascularization in patients at high risk of complications after contrast arteriography (CA).

METHOD

Forty-five consecutive patients at high risk of post-CA complications because of chronic renal insufficiency, diabetes mellitus, advanced age, or the need for brachial artery catheterization or graft puncture had Gd-MRA as first-line angiography before a surgical or endovascular procedure for lower limb ischemia.

RESULTS

After Gd-MRA, 59 procedures were performed, including 38 surgical reconstructions, 17 endovascular procedures, and four amputations. Complementary CA was only required in seven patients for whom a below-knee bypass was planned. Cumulative patency rates at 1 and 24 months were, respectively, 91% and 91% for suprainguinal bypasses, 100% and 92% for infrainguinal above-knee bypasses, 80% and 57% for below-knee bypasses, and 92% and 76% for iliofemoral angioplasties. After 24 months of follow-up, limb salvage, amputation, and mortality rates were, respectively, 86%, 3.5%, and 7% for stage II ischemia and 48%, 11%, and 30% for stages III and IV.

CONCLUSION

Gd-MRA can be proposed for first-line preoperative imaging in the management of lower limb ischemia for patients at high risk and permits the selective use of CA as a second-line examination if a below-knee bypass is required.

Color-flow duplex scanning of the leg arteries by use of a new echo-enhancing agent

OBJECTIVE

This was a dose-finding and effectiveness study of a newly developed contrast-enhancing agent, sulphur hexafluoride (SF(6)), in patients with peripheral arterial disease in whom the therapeutic policy could not be established on the basis of standard color-flow duplex scanning of the leg arteries.

METHODS

In this open-label, randomized, dose-ranging, crossover design, 14 patients in whom the assessment of vessel patency was difficult because of poor visibility (low-flow state) or extensive wall calcifications were studied. Contrast-enhanced duplex scanning was performed on the upper leg (n = 4), lower leg (n = 6), or pedal (n = 4) arteries after intravenous injection of four different dosages of SF(6). The results were compared with those from selective angiography of the vessel of interest. Contrast duration and agreement about the diagnosis and the confidence in the diagnosis were obtained before and after administration of the contrast agent.

RESULTS

No adverse effects of the contrast agent were seen. Overall agreement was reasonable with regard to vessel patency between contrast-enhanced duplex scanning and angiography (71%). Nine of 14 vessels (64%) appeared open when contrast was applied. In four cases this could not be confirmed by angiography; in two of these cases this was due to the presence of collateral vessels. All vessels that appeared occluded with the contrast agent were also occluded on the angiogram. The confidence in the diagnosis increased from 56% to 91% after contrast administration (P <.0001).

CONCLUSION

SF(6)-enhanced color-flow duplex scanning is a safe method that may improve the assessment of the patency of leg arteries, particularly in low-flow states. The visualization of collateral vessles during (enhanced) duplex scanning may be misleading because they may be regarded as the vessel of interest.

Critical Limb Ischemia

Patients with critical limb ischemia (CLI) present with ischemic rest pain or with tissue loss. Tissue loss, in its mildest presentation, includes focal ischemic ulceration or nonhealing wounds. Gangrene is the manifestation of severe chronic ischemia. Without revascularization, patients with CLI are at risk for limb loss and for potentially fatal complications from the progression of gangrene and the development of sepsis. The best patient outcomes are achieved when the diagnosis and appropriate treatment for CLI are not delayed. Simple noninvasive tests, such as measurement of ankle-to-brachial indices or toe Doppler pressures, take only minutes to provide sufficient information to confirm the diagnosis of peripheral artery disease (PAD) and to document the severity of limb ischemia. Subsequent diagnostic imaging studies, such as arteriography, magnetic resonance angiography, or ultrasound duplex scanning, provide the detailed information needed to plan revascularization therapy. Balloon angioplasty and stenting work best for focal segments of narrowing or short occlusions of the iliac arteries, but endovascular treatments yield progressively poorer results with longer and more distal lesions. Long segments of occlusion, especially those distal to the common femoral artery, are best treated with surgical bypass. Pharmacotherapy and adjunctive therapies, such as topical therapies or hyperbaric oxygen treatment, may have a limited role in patients in whom revascularization procedures have failed or for those in whom revascularization is not technically possible--particularly when amputation is the only alternative. Prostanoids are the best-studied class of drugs for such applications, but their use is still investigational in the United States. Though other medical approaches, such as use of other vasoactive agents, drugs that treat claudication, or gene-induced angiogenesis may prove useful, they do not yet have demonstrated roles in the treatment of patients with CLI.

Prospective comparison of MR phase-contrast velocimetry with intravascular doppler US during infrainguinal artery angioplasty

PURPOSE

To evaluate the accuracy of magnetic resonance (MR) velocimetry for quantitative assessment of stenosis in patients undergoing percutaneous transluminal angioplasty (PTA).

MATERIALS AND METHODS

Thirty patients underwent PTA of the infrainguinal region. To assess hemodynamic parameters of lesions, MR phase-contrast velocimetry with a circular-polarized extremity receiver coil and a cardiac gated gradient echo sequence was conducted before and 1 day after PTA. Additionally, all lesions were examined by means of intravascular Doppler flow measurements (0.018-inch wire, 12 MHz). From these data, the degree of stenosis was calculated and a comparison of MR velocimetry with intravascular Doppler US was undertaken.

RESULTS

Correlation between calculated grade of stenosis for MR velocimetry and intravascular Doppler US was good and significant (r = 0.74; P <.001). Calculated luminal stenosis grade were similar for both methods before PTA (intravascular Doppler US: 0.62 +/- 0.18, MR velocimetry: 0.54 +/- 0.19; P =.17 with paired Student t-test) and after PTA (0.25 +/- 0.23 and 0.3 +/- 0.2, respectively; P =.56).

CONCLUSION

MR velocimetry results in reliable noninvasive in vivo flow measurements and allows accurate assessment of stenosis in a clinical setting.