Misplacement of a vena cava filter into the spinal canal.

We report the case of a 70-year-old male with a complication of misplacement of a vena cava filter into the spinal canal. This likely happened as a result of penetration of the wire and filter sheath through the iliac vein or vena cava into the retroperitoneum, vertebral foramina, and spinal canal at the level of L2 and L3. Due to the patient's condition, the filter was not removed and no neurologic symptoms have occurred. This represents the first reported case of a filter deployment into the spinal canal. Although placement of vena cava filters is a relatively safe procedure, complications are seen commonly due to the large number of procedures performed. Spinal complications, however, are rarely reported. This is the first reported case of the inadvertent placement of a vena cava filter into the spinal canal.

Cerebral venous hypertension and blindness: a reversible complication.

A 57-year-old woman developed blindness during treatment for sarcoidosis-induced end-stage renal disease. An initial renal transplantation failed, and hemoaccess was maintained with multiple central catheters and upper extremity prosthetic arteriovenous grafts. A successful second transplantation eliminated her need for hemodialysis, but a right brachial to internal jugular graft remained patent. Progressive visual loss 2 years after transplantation prompted ophthalmic evaluation which initially revealed unilateral left optic nerve edema and visual loss, ultimately worsening over several months to no light perception in the left eye, 20/60 vision in the right eye, and bilateral papilledema. Arteriography demonstrated cerebral venous hypertension attributed to the functioning hemoaccess graft. Permanent graft occlusion normalized the papilledema, and visual field defects in the right eye and visual acuity returned to 20/20 in the right eye.

Technical challenges in a program of carotid artery stenting.

OBJECTIVES: Successful carotid artery stenting (CAS) involves gaining access to the common carotid artery, characterizing and crossing the lesion, deploying an anti-embolic device and stent, and retrieving the anti-embolic device. These steps are critical determinants of the complexity of the procedure. The frequency with which technical challenges are encountered during CAS is ill-defined. The purpose of this investigation was to review the incidence and types of technical challenges encountered during CAS and determine their effect on outcome. METHODS: Data were prospectively collected for 194 consecutive CAS procedures (177 patients) and separated into group 1, standard CAS technique, and group 2, procedures with technical challenges requiring modifications to the technique. Technical challenges were defined as difficult femoral arterial access (aortoiliac occlusive disease), complex aortic arch anatomy (elongated or bovine arch, deep takeoff of the innominate artery, tandem stenoses (CCA, innominate artery), difficult internal carotid artery anatomy (tortuosity, high-grade stenosis), and circumferential internal carotid artery calcification. The incidence of technical challenges, types of technical modifications required, and effect on outcomes were determined. RESULTS: Fifty technically challenging situations (26%) were encountered in 194 CAS procedures (group 2), which required advanced technical skills. Standard methods were used in the other 144 procedures (group 1, 74%). No significant differences in 30-day stroke and death rates were noted between the groups (group 1, 3.1%; group 2, 2.0%; P = .564). CONCLUSIONS: Twenty-six percent of the procedures required a modification in the standard technique for successful CAS. Circumferential calcification and severe tortuosity continue to be relative contraindications to CAS. Recognition of these technical challenges and increasing facility with the methods to manage them will enable expanded use of CAS without increased morbidity and mortality.

Cerebral oximetry monitoring during carotid endarterectomy: effect of carotid clamping and shunting.

Cerebral oximetry is a simple method of measuring regional cerebral oxygen saturation (rSO(2)). One promising application is its use during carotid endarterectomy (CEA) to help minimize the risk of perioperative stroke. The authors used the INVOS-4100 cerebral oximeter at several steps during CEA to measure the effect of carotid clamping and shunting on rSO(2). The authors prospectively evaluated 42 consecutive CEAs in 40 patients. All had CEA under general anesthesia with the routine use of a Javid shunt. The INVOS-4100 oximeter was used to measure rSO(2) before clamping (t1), after clamping but before shunting (t2), 5 minutes after shunt insertion (t3), and after patch closure with reestablished flow (t4). The Wilcoxon signed-rank and rank-sum tests were used for analysis. Clamping of the internal carotid artery (t1 vs t2) resulted in a drop of ipsilateral rSO(2) by -12.3% (p < 0.001). Shunt insertion (t2 vs t3) increased rSO(2) by 10.9% (p < 0.001). Contralateral rSO(2) for the same time periods was insignificant. Patients with preoperative neurologic symptoms had a greater decrease in rSO(2) after clamping (-18.4%) compared with a decrease of -10.4% in asymptomatic patients (p = 0.037). Cerebral oximetry monitoring is simple and inexpensive. The study showed statistically significant changes in rSO(2) as a result of clamping and shunting of the carotid artery. Symptomatic patients had a greater drop in rSO(2).

Surgical intervention for acute intestinal ischemia: experience in a community teaching hospital.

The aim of this study was to evaluate the current management of acute mesenteric ischemia secondary to thrombotic or embolic occlusion of visceral vessels in a community teaching hospital. Between October 1997 and July 2000, a review of all hospital discharges revealed 83 patients with a discharge diagnosis of "acute vascular insufficiency-intestine." Among these 83 patients, 22 cases of acute mesenteric ischemia were confirmed. Management of these 22 patients was divided into 2 groups for analysis. In Group A, 14 patients were aggressively treated with visceral angiography (n=10), visceral artery bypass (n=8), visceral embolectomy (n=4), and bowel resection (n=7). In 8 of 14 of these patients, surgical intervention occurred in less than 24 hours from presentation. In Group B, 8 patients were managed with supportive care because of advanced age (mean age = 86 +/- 7 years), comorbid conditions, or patient and family preference. Postoperative morbidity in Group A consisted of cardiac events (n=3), pulmonary insufficiency (n=5), and prolonged gastrointestinal tract dysfunction (n=3). Twelve of 14 patients in Group A survived and were discharged, whereas only 2 of 8 patients in Group B survived and were discharged from the hospital. Although the literature suggests that there can be a significant delay in the diagnosis and treatment of acute mesenteric ischemia, the early recognition and aggressive treatment of acute mesenteric ischemia resulted in a good survival rate. Supportive management of very elderly and debilitated patients needs to be considered on a case-by-case basis. Although the outlook for such patients is dismal, survivors are possible as demonstrated by this series.

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.

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.