Contemporary management of "high-risk" patients with carotid stenosis

The concept of a "high-risk" carotid endarterectomy patient has been suggested in an effort to justify the application of carotid angioplasty and stenting outside of clinical trials. Contemporary results of carotid endarterectomy in this subgroup of patients would argue against the existence of a high-risk patient. Until randomized prospective trials establish the role of carotid angioplasty and stenting in carotid bifurcation disease, this new technology should be restricted to recurrent and radiation-induced disease.

Treatment of patients with combined coronary and carotid atherosclerosis

In this article we will review some of the issues surrounding the prevention of neurological and cardiac morbidity in patients with combined coronary and carotid disease and discuss the role of various algorithms of care. Advances in medical care have resulted in a significant prolongation of life. Since atherosclerosis is a disease of aging, the number of patients who come to the attention of cardiac and vascular surgeons has increased and so have their age and co-morbidities. Three decades ago the most common coronary operation was a 1 or 2 vessel bypass in a patient in their 6(th) or early 7(th) decade and the mean age of patients undergoing carotid endarterectomy (CEA) was under 70. Advances in percutaneous coronary techniques and better 8(th) decade and operation on patients over 80 a common occurrence. A similar though less dramatic increase has occurred in the age of patients undergoing CEA. One result of this is that patients often have significant multisite atherosclerosis. Management of these patients has become an increasing concern for cardiac and vascular surgeons. Myocardial ischemia is the principal non-neurological merbidity after CEA as well as the major cause of late death. As cardiac risk after coronary surgery revascularization and its prevention has become an increasing focus for surgeons.

Modeling stroke risk after coronary artery bypass and combined coronary artery bypass and carotid endarterectomy

BACKGROUND AND PURPOSE

The goals of this study were to compare the ability of statewide and institutional models of stroke risk after coronary artery bypass (CAB) to predict institution-specific results and to examine the potential additive stroke risk of combined CAB and carotid endarterectomy (CEA) with these predictive models.

METHODS

An institution-specific model of stroke risk after CAB was developed from 1975 consecutive patients who underwent nonemergent CAB from 1994 to 1999 in whom severe carotid stenosis was excluded by preoperative duplex screening. Variables recorded in the New York State Cardiac Surgery Program database were analyzed. This model (model I) was compared with a published model (model II) derived from analysis of the same variables using New York statewide data from 1995. Predicted and observed stroke risks were compared. These formulas were applied to 154 consecutive combined CAB/CEA patients operated on between 1994 and 1999 to determine the predicted stroke risk from CAB alone and thereby deduce the maximal added risk imputed to CEA.

RESULTS

Risk factors common to both models included age, peripheral vascular disease, cardiopulmonary bypass time, and calcified aorta. Additional risk factors in model I also included left ventricular hypertrophy and hypertension. Risk factors exclusive to model II included diabetes, renal failure, smoking, and prior cerebrovascular disease. Our observed stroke rate for isolated CAB was 1.7% compared with a rate predicted with model II (statewide data) of 1.56%. The observed stroke rate for combined CEA/CAB was 3.9%. When the Stony Brook model (model I) based on patients without carotid stenosis was used, the predicted stroke rate was 2.8%. When the statewide model (model II), which included some patients with extracranial vascular disease, was used, the predicted stroke rate was 3.4%. The differences between observed and predicted stroke rates were not statistically significant.

CONCLUSIONS

Estimation of stroke risk after CAB was similar whether statewide data or institution-specific data were used. The statewide model was applicable to institution-specific data collected over several years. Common risk factors included age, aortic calcification, and peripheral vascular disease. The observed differences in the predicted stroke rates between models I and II may be due to the fact that carotid stenosis was specifically excluded by duplex ultrasound from the patient population used to develop model I. Modeling stroke risk after CAB is possible. When these models were applied to patients undergoing combined CAB/CEA, no additional stroke risk could be ascribed to the addition of CEA. Such models may be used to identify groups at increased risk for stroke after both CAB and combined CAB/CEA. The ultimate place for CEA in patients undergoing CAB will be defined by prospective randomized trials.

Angiographic improvement after rapid intermittent compression treatment [ArtAssist] for small vessel obstruction

A case is presented of a female ex-smoker who underwent bypass or exploration of all three below-knee arteries with failed results. Three separate arteriograms, performed at other academic institutions, demonstrated progressive, severe involvement of the pedal arteries. Therefore, the patient was prepared to undergo below-knee amputation surgery for uncontrollable rest pain and progressive necrosis of the forefoot; instead, the patient underwent 4 months of intermittent compression treatment. A fourth arteriogram, performed after 4 months of intermittent compression treatment (using rapid inflation/deflation and high-pressure cycle; ArtAssist demonstrated marked improvement of the posterior tibial artery runoff and development of more extensive collateral arteries in the calf. The patient's rest pain subsided and successful limb salvage was accomplished with a modified transmetatarsal amputation. This case could encourage other practitioners to repeat arteriography after compression treatments, which may redirect the treatment plan for selected patients with critical limb ischemia and nonreconstructable peripheral vascular disease.

High-risk carotid endarterectomy: fact or fiction

OBJECTIVE

It has been proposed that patients whose conditions do not meet North American Symptomatic Carotid Endarterectomy Trial inclusion criteria or have anatomic risk factors constitute a "high-risk" group for carotid endarterectomy (CEA) and might be candidates for primary carotid angioplasty stenting. Our objective was to review a consecutive series of isolated CEAs, identify the number of such patients at high risk, and determine whether their operations were associated with increased complication rate.

METHODS

Consecutive isolated CEAs performed between June 1996 and June 2001 were reviewed. High-risk comorbidities included: age 80 years or more (n = 80), New York Heart Association class III/IV angina (n = 16), Canadian class III/IV heart failure (n = 4), myocardial infarct 6 months or less (n = 11), steroid-dependent or oxygen-dependent pulmonary disease (n = 4), and creatinine level of 3 or more (n = 13). Anatomic high risk was defined by: contralateral occlusion (n = 66), lesion above C(2) or requirement of digastric division (n = 53), reoperation (n = 29), and neck radiation (n = 3). Statistical analysis was with chi(2) analysis.

RESULTS

Of 788 patients reviewed, 228 (29%) were classified as high risk by one or more of the previous criteria (63% comorbidity, 28% anatomy, 9% both). Presence of preoperative neurologic symptoms and postoperative results were similar across all patient groups. The total stroke and death rate was 1.1% for all the patients. Six patients had postoperative strokes (0.8%), and three patients died of myocardial infarcts (0.4%). The stroke and death rate was 1.3% in the high-risk group as compared with 1.1% in the normal-risk group (P =.51).

CONCLUSION

The concept of the high-risk CEA must be critically reexamined. Although 29% of patients for CEA were high risk as defined by others, we found no evidence that this influenced the results after CEA. Patients with significant medical comorbidities, contralateral carotid occlusion, and high carotid lesions can undergo operation without increased complications. If a high-risk group exists, it is small and restricted to reoperation or radiated neck (4% in this series). With this possible exception, carotid angioplasty stenting should be restricted to randomized clinical trials.

Endovascular repair of an arteriovenous fistula from a ruptured hypogastric artery aneurysm--a case report

A spontaneous ilioiliac arteriovenous fistula secondary to rupture of a hypogastric artery aneurysm is an unusual occurrence. A case of an endovascular repair of this challenging problem is reported.

Limb salvage using high-pressure intermittent compression arterial assist device in cases unsuitable for surgical revascularization

HYPOTHESIS

Intermittent compression therapy for patients with inoperable chronic critical ischemia with rest pain or tissue loss may have beneficial clinical and hemodynamic effects.

STUDY DESIGN

Case series of 14 consecutive ischemic legs that underwent application of a 3-month treatment protocol during a 2(1/2)-year study.

SETTING

Veterans Administration Hospital.

PATIENTS

Thirteen patients with 14 critically ischemic legs (rest pain, n = 14; tissue loss, n = 13) who were not candidates for surgical reconstruction were treated with rapid high-pressure intermittent compression. The patients had a mean age of 76.2 years, 8 were diabetic, and they represented 10% of referrals for chronic critical ischemia. They were not amenable to revascularization owing to lack of outflow arteries (n = 7), lack of autogenous vein (n = 5), or poor general medical condition (n = 3).

INTERVENTION

All patients were instructed to use the arterial assist device for 4 hours a day at home for a 3-month period.

MAIN OUTCOME MEASURES

Limb salvage and calibrated pulse volume amplitude.

RESULTS

After 3 months, 9 legs had a significant increase in pulse-volume amplitude (P< .05). These legs were salvaged, whereas the 4 amputated legs demonstrated no hemodynamic improvement. We noted a direct correlation between patient compliance and clinical outcome. Patients in whom limb salvage was achieved used their compression device for longer periods of time (mean time, 2.38 hours a day) compared with those who underwent amputation (mean time, 1.14 hours a day) (P< .05). These mean hours of use were derived from an hour counter built into the compression units.

CONCLUSIONS

Intermittent high-pressure compression may allow limb salvage in patients with limb-threatening ischemia who are not candidates for revascularization. Further studies are warranted to assess intermittent compression as an alternative to amputation in an increasingly older patient population.

Operation for acute peripheral arterial occlusion: is it still the gold standard?

Acute arterial ischemia secondary to peripheral arterial occlusion has been shown to cause severe morbidity and mortality. Debate continues about the best mode for initial therapy of patients presenting with acute limb ischemia (ALI). Surgery traditionally has been used as the sole mode of therapy. Since the introduction of catheter-directed thrombolysis (CDT), role of surgery as the "gold standard" has been questioned. In this report the authors review the role of surgery compared with CDT. They discuss the role of prompt diagnosis on the outcome of the intervention and the results of CDT compared with the surgical standard. The best therapy for ALI is the one that is instituted early; intervention should be tailored based on the initial clinical presentation, and surgery remains the gold standard with CDT, an adjunctive tool for the vascular surgeon dealing with acute peripheral arterial occlusion (PAO).

Long-term assessment of cryopreserved vein bypass grafting success

PURPOSE

When autogenous vein is unavailable, cryopreserved veins have been used in patients as a means of attempted limb salvage. We evaluated the long-term patency and limb salvage rates for patients undergoing bypass grafting with cryopreserved veins.

METHODS

Medical records were reviewed for patients undergoing cryovein bypass grafting at two hospitals from 1992 to 1997. Follow-up data were obtained from subsequent admissions and office records. Primary outcomes were death, amputation, and primary patency. Skin integrity and additional bypass grafting procedures were assessed when data were available. Analysis was performed by means of life-table and chi(2) analyses with the Statistical Package for Social Sciences (SPSS).

RESULTS

Seventy-six patients (mean age, 70 +/- 11 years) underwent 80 procedures. Indications for surgery were tissue loss (63%), rest pain (24%), acute ischemia (11%), and other (2%). Early complications included 3 deaths (4%), 14 acute thromboses (18%), and 7 major amputations (9%). The mean follow-up period was 17.8 +/- 20.89 months (range, 0-77 months). The primary patency rate was determined to be 36.8% at 1 year and 23.6% at 3 years by means of life-table analysis. The limb salvage rate was 65.5% at 1 year and 62.3% at 3 years. Skin integrity was found to be compromised in 17 (55%) of 31 patients who were available to follow-up. Nine patients (11.3%) underwent additional ipsilateral revascularization or revisions, with one of three of these patients eventually requiring a major amputation.

CONCLUSION

Cryopreserved vein may be a reasonable alternative conduit for limb salvage when no autogenous tissue is available; it has an acceptable limb salvage rate (62.3%) at 3 years. Long-term patency remains relatively poor, with only 23.6% of originally placed grafts patent at 3 years. The use of cryopreserved veins should be strictly confined to limb salvage after a thorough search for autogenous tissue has been exhausted.

Coronary and carotid operations under prospective standardized conditions: incidence and outcome

BACKGROUND

No randomized trial has yet evaluated the hypothetical benefit of carotid endarterectomy with coronary artery bypass grafting. This prospective review was undertaken to determine the differences between observed and predicted complication rates, as well as to define new predictors and assess costs in a standardized population.

METHODS

A prospective nonrandomized study was undertaken over a 4-year period involving all coronary artery bypass graftings done at one institution. Operative procedure was standardized. All patients underwent preoperative screening for carotid disease. If 80% or more stenosis was present, combined coronary artery bypass grafting and carotid endarterectomy was performed.

RESULTS

Of 2,071 patients, 1,987 had coronary artery bypass grafting only. In that group there were 34 strokes (1.7%) and 41 deaths (2.0%). Eighty-four patients underwent combined coronary artery bypass grafting/carotid endarterectomy and in that group there were four strokes (4.7%) and five deaths (5.9%). Independent risk factors for postoperative stroke were age (odds ratio 1.09; 95% confidence interval 1.04, 1.3), hypertension (odds ratio 2.67; 95% confidence interval 1.22, 5.23), extensively calcified aorta (odds ratio 2.82; 95% confidence interval 1.34, 5.97), and bypass time (odds ratio 1.01; 95% confidence interval 1.00, 1.02). Cost of a stroke was significant (p < 0.05) in both groups.

CONCLUSIONS

Patients with carotid disease fall into a higher risk group than patients without it. This increased risk is not because of carotid disease alone. Patients without significant carotid disease, who suffered a perioperative stroke, fell into an even higher risk category. Furthermore, carotid endarterectomy was not a significant risk factor by either the univariate or the multivariate analysis.

Total posterior approach for femoropopliteal bypass

Standard approaches to the femoral and popliteal arteries are used in most extremity arterial reconstructions. In unusual circumstances, such as infection, reoperation, or variant anatomy, novel approaches to infrainguinal bypass may be useful, particularly in reoperative or infected cases. One such approach involves exposure of the femoral and popliteal arteries through posterolateral incisions with the patient prone. The major advantage of this exposure is the increased accessibility to the distal above-knee popliteal artery, which is not easily reached through either medial or lateral incisions. This approach also can be useful in cases of significant groin sepsis. The details of this exposure and its application in an illustrative case are presented.

Rapid intermittent compression increases skin circulation in chronically ischemic legs with infra-popliteal arterial obstruction

BACKGROUND

Intermittent pneumatic compression (IPC) has been shown, by duplex, to increase popliteal artery flow in normal legs and in legs with superficial femoral artery occlusion. The objective of this study was to see if IPC improves distal circulation in legs with severe infra-popliteal disease.

PATIENTS AND METHODS

Sixteen chronically ischemic legs with arteriographically demonstrated crural or pedal disease were studied during compression with an ArtAssist compression-device. This device delivers rapid compression of the foot and calf. Cutaneous laser-Doppler flux was measured continuously at the dorsal aspect of the distal forefoot. The findings were compared to those in thirteen normal controls of similar age.

RESULTS

In ischemic legs, the spontaneous changes in skin-flux are minimal: mean resting flux in sitting position was 0.87 +/- 0.46 AU (Arbitrary Units). Upon activation of the compression device the maximum flux increased to 4.55 +/- 1.35 AU. The difference was statistically significant (p < 0.001). This response was similar to that in normal controls.

CONCLUSION

Arterial flow augmentation upon compression is associated with increased skin-flux. This response remains present in severe disease of the crural outflow-arteries. Further investigation to define the role of intermittent compression for management of chronic arterial disease is warranted.

Weighing risks in abdominal aortic aneurysm. Best repaired in an elective, not an emergency, procedure

Abdominal aortic aneurysms are believed to result from several factors, one probably being inflammation that leads to dilatation, plaque deposition, and degeneration of the arterial wall. Most of these aneurysms are asymptomatic, but abdominal or back pain, shock, and a pulsatile abdominal mass indicate rupture. Initial aneurysm size exceeding 5 cm (2 in.) in diameter and the presence of hypertension and COPD are important predictors of rupture. The overall operative mortality rate with elective repair of an abdominal aortic aneurysm has been reported to range from 0.9% to 5% at university medical centers, and it is only slightly higher at community hospitals. However, with a ruptured aneurysm and emergency repair, the mortality rate rises to about 75%. Several long-term studies using life-table methods have found that 5-year survival rates after aneurysm repair range from 49% to 84%. This rate is significantly better than the 5-year survival rate of patients who did not have an abdominal aortic aneurysm repaired. However, it is not as good as that of the normal age-matched population, probably because many patients with an aneurysm have concomitant coronary artery disease.

Developments in diagnosis and classification of venous disorders: non-invasive diagnosis

PURPOSE

This review examines the many techniques that have been used for the non-invasive diagnosis of acute and chronic venous disease and was conducted by members of the Committee on Research of the American Venous Forum. It proposes to identify those techniques with the greatest clinical potential, to suggest algorithms for the clinical application of non-invasive techniques in the identification of acute deep venous thrombosis and chronic venous insufficiency, and to identify areas of deficient knowledge and potential areas for future research initiatives.

METHODS

Review of pertinent clinical and research material.

RESULTS

Impedance plethysmography and ultrasonic imaging are the primary non-invasive tools used in the diagnosis of acute deep venous thrombosis. At present, ultrasonic imaging techniques are recommended on the basis of greater diagnostic accuracy in recent comparative clinical trials. Data would suggest that serial evaluation should probably be viewed as the preferred option for symptomatic patients with a negative initial examination and the presence of risk factors or physical findings suggesting a proximal deep venous obstruction/thrombosis. Chronic venous disease is the result of valvular incompetence, with or without associated venous obstruction. Duplex imaging can be used to determine the location and extent of reflux; however, there are reported procedural variations in the performance and interpretation of such studies. Recent innovations in air plethysmography may provide a means of quantifying volume changes, and permit an objective characterization of venous reflux and calf pump efficiency.

CONCLUSIONS

There are still significant questions that need to be answered by well-designed research initiatives. Research applications that incorporate non-invasive diagnostic techniques may involve the diagnosis, treatment and natural history of acute deep venous obstruction/thrombosis and chronic venous insufficiency, assessment prior to and following venous reconstruction, and the basic science aspects of acute and chronic venous disease. At present, a lack of common standards is, by far, the greatest impediment to an organized research approach to venous disease.

Endothelial dysfunction following thrombolysis in vitro

OBJECTIVES

Thrombolytic therapy is frequently used to manage vascular graft thrombosis. However, long-term patency after thrombolysis remains poor. The purpose of this study was to characterise the morphological and functional response of endothelial cells (EC) exposed to a thrombus and subsequently lytic therapy.

METHODS

Human EC were exposed to human whole blood thrombus for 2, 6, 12, and 24 h. The thrombus was lysed with urokinase. Cell morphology was studied with electron microscopy. Northern blot analyses were performed with human c-DNA probes for endothelin-1, thrombomodulin, tissue factor, tissue plasminogen activator, plasminogen activator inhibitor, and triose phosphate isomerase.

RESULTS

EC retraction occurred for each period of incubation. Thrombomodulin expression was increased 2.2-fold at 6 h and 2.4-fold at 24 h. t-PA expression was depressed proportionally to the duration of thrombus exposure. PAI and TF expression transiently increased 1.5-fold at 2 h of exposure and returned to baseline at 6 h. Endothelin expression remained unchanged.

CONCLUSIONS

Except for a transient increase in TF expression and reversal of the tPA/PAI ratio, EC exposed to thrombus do not appear to become actively procoagulant. The increase in TM expression may reflect enhanced thromboresistance. However, EC retraction may be responsible for an increase thrombogenicity of saphenous vein graft after thrombosis and Urokinase therapy.

Animal models for the study of lower extremity chronic venous disease: lessons learned and future needs

The purpose of this review is to define animal models of chronic venous disease and to demonstrate how animal studies can impact our understanding and treatment of this disorder. To this end an extensive literature search was conducted highlighting potential animal models of chronic lower extremity venous disease. Scientific investigations using animals to study particular aspects of this disease are also reviewed. This review was conducted by members of the Committee on Research of the American Venous Forum to help provide direction for future venous research endeavors. Useful models of chronic venous occlusive disease involve controlled ligation of a major lower limb vein and multiple tributaries. Such a model can provide sustained venous hypertension and studies using this model have confirmed that an isodiametric graft can provide early hemodynamic relief. Models of primary, postphlebitic, and isolated chronic deep venous insufficiency are available for study. Valve repair or transplantation can positively impact the insufficiency observed in these models. Investigations into valve substitutes have generally been disappointing or are undergoing early evaluation. In conclusion, animal models for the study of some aspects of chronic venous disease do exist and have already affected our clinical approach to patients. The scientific study of basic pathophysiology, diagnostics, end-organ response, and long-term surgical treatments of this disorder in well-controlled animal experiments have not been conducted.

Cost management strategies for carotid endarterectomy

BACKGROUND

We developed a model for capitation and global pricing for carotid endarterectomy.

METHODS

A care algorithm for diagnosis, perioperative management, and postoperative care using cost data was developed. Perioperative care charges were extrapolated from a 1-year experience and applied to models to determine pricing for a 1-year global fee and a 5-year capitated contract.

RESULTS

Global pricing was estimated at $12,071 per patient while a capitated price for 5-year care was $17,175. Based on the age mix of the population, a per member, per month cost could be calculated assuming a frequency of 414 procedures per 100,000 patients over age 65 and 31 procedures per 100,000 patients under 65. Sources of costs were extensive preoperative diagnostic testing, particularly angiography, brain imaging, and cardiac evaluation.

CONCLUSIONS

Global pricing and capitation are both feasible for carotid endarterectomy. Each approach has unique risks and benefits.

The role of thrombolytic therapy in the management of paradoxical embolism

Paradoxical emboli are considered a rare event, representing less than 2% of all arterial emboli. The most common intracardiac defect associated with paradoxical emboli is a patent foramen ovale. Most commonly, a pulmonary embolism is the cause of the acute increase in right atrial pressure leading to a reversal of intracardiac flow and passage of venous embolic material to the left heart. We present a patient with a pulmonary embolism and paradoxical emboli, and discuss therapeutic approach. We suggest that the treatment of choice for the patient with pulmonary embolism and non-limb-threatening acute ischemia due to a paradoxical emboli should be thrombolytic therapy and intracaval filter placement, followed by patent foramen ovale repair.