Faculty Bibliography

There are greater than 120,000 above-knee amputations (AKA) and below-knee amputations (BKA) performed in the USA each year. Traditionally, general anesthesia (GA) was the preferred modality of anesthesia. The use of regional nerve blocks has recently gained popularity, however, without the supporting evidence of any mortality benefits. Our objective was to evaluate whether regional nerve blocks yield significant mortality reduction in major lower-extremity amputations. Retrospective data of both AKA and BKA procedures at the Maimonides Medical Center from 2005 to 2009 were analyzed. Patients received either general sedation, spinal or ultrasound-guided regional nerve blocks as per decision of the attending anesthesiologist. Regional nerve blocks for major lower-extremity amputations consisted of femoral, sciatic, saphenous and popliteal nerve blocks. A retrospective inquiry of 30-day mortality was performed with reference to the Social Security Death Index and hospital records. One hundred and fifty-eight patients were included in the study (82 men and 86 women with mean age of 74.5 years +/- 12.9 SD, range of 33-98 years) of which 46 patients had regional nerve blocks and 112 had GA or spinal blocks. Patients who received both regional blocks and GA/spinal blocks within 30 days were excluded. The overall 30-day mortality was 17.1% (27 patients) consisting of 15.2% for regional nerve analgesia versus 17.9% for GA/spinal blocks (P = 0.867). Age did not affect mortality outcome in either groups of anesthesia modality. Our analysis did not reveal any mortality benefit of utilizing regional nerve block over GA or spinal blocks.

BACKGROUND: Balloon assisted maturation (BAM) is a recent, innovative, yet controversial method for developing autogenous arterio-venous fistulae (AVF), with little supportive data. Few retrospective studies have addressed the efficacy of BAM and cofactors affecting successful maturation. We conducted a retrospective analysis of our vascular access database to compare possible factors associated with a successful BAM, as determined by increase in volume flow of the fistulae. METHODS: Between 2009 and 2010, data was prospectively collected on patients undergoing BAM of their AVF under ultrasound guidance at our institution. 30 of these patients, consisting of 143 BAMs, were retrospectively analyzed. Data collection included: past medical history, age, number of BAM procedures preformed, volume flow measurement (VFM) in mid-fistulae, size of balloon used, and presence of post procedural wall hematoma. VFM was determined with duplex within one month prior to and subsequent to each BAM performed. RESULTS: Of the 30 patients, consisting of 143 BAMs, the average age was 69 years old + 15 (range 38-92) with 20 males and 10 females. The most common risk factors were hypertension (n = 27) and diabetes mellitus (n = 16). The average BAM per patient was 4.8 (range 1-7). Of the 143 BAM procedures, 4 were excluded due to absence of preoperative or postoperative duplex. In 139 BAMs, 74 developed a post procedural hematoma as observed on duplex, and 76 showed an increase in VFM. In all BAMs analyzed, there was no correlation observed between the presence of a hematoma and increase in VFM (P = 0.87). Hematomas occurred most frequently during the second BAM procedure, with 24.3% of all hematomas observed. In 139 BAMs, 8 different balloon sizes were used, 3 mm-10 mm, with the 7mm balloon being the most frequently used (n = 34). No significant difference was noted between increase in VFM in 3 mm to 7 mm balloons. A 8 mm balloon was used in 31 BAMs with 22 developing hematomas. Of the 8mm balloon group, a statistical difference was noted between percent increase in VFM with presence of a hematoma and percent increase in VFM without presence of a hematoma (P = 0.027). CONCLUSIONS: These preliminary data, suggest that a more aggressive approach to BAM, with use of larger balloons to create hematoma formation and minimizing excessive dilatation procedures, may have a significant impact on performing a successful maturation in respects to increase in VFM.

BACKGROUND: To examine the effect of office-based duplex-guided balloon-assisted maturation (DG-BAM) on arteriovenous fistula (AVF), we retrospectively analyzed our experience. METHODS: Over the past 10 months, we performed 185 DG-BAMs (range, 1-8 procedures; mean, 3.7) in 45 patients (29 male, 16 female; mean age, 68.2 +/- 12.8 years) with 31 radial-cephalic, 7 brachial-cephalic, and 7 brachial-basilic AVFs. Balloon sizes (3-10 mm) were chosen based on duplex measurements (1-2 mm larger than minimal vein diameter). Forearm AVFs were dilated to 8 mm, and arm AVFs were dilated to 10 mm. RESULTS: All cases but one (99.5%) were successfully dilated. This exception was a large AVF rupture that required surgical repair. AVFs failed to mature in seven of the remaining 44 patients (16%) despite DG-BAM because of proximal vein stenoses (PVS). Four patients had cephalic arch stenoses, and three had proximal subclavian vein stenoses. Arm AVFs were more commonly associated with PVS (6 of 14 patients, 43%) as compared with the ones placed in the forearm (1 of 30 patients, 3.3%), with a P value of 0.0024. All these seven AVFs subsequently matured after successful balloon angioplasty of the venous outflow. CONCLUSIONS: These data suggest that office-based DG-BAM of AVFs is feasible, safe, and averts nephrotoxic contrast and radiation. PVS appear to be the most common cause of failure for AVFs subjected to BAM. Because arm AVFs are at increased risk of PVS, we suggest that a careful duplex evaluation of the outflow be performed in these cases and in all AVFs that fail to mature.

BACKGROUND: To identify patients with pulmonary embolism (PE) without deep venous thrombosis (DVT), and to compare them with those with an identifiable source on upper (UED) and lower-extremity venous duplex scans (LED). METHODS: We performed a retrospective review of 2700 computed tomography angiograms of the chest between January 2008 and September 2010 and identified 230 patients with PE. We then evaluated the results of UED and LED and divided the patients into four groups based on the results of their duplex studies. We compared patients with PE and DVT with those with PE and no DVT in terms of age, gender, size and location of PE, critical illness, malignancy, and in-hospital mortality. RESULTS: We identified 152 women and 78 men (mean age, 68 years) with PE. One hundred thirty-one patients had a documented source of PE (group 1). Fifty-three patients had negative LED results, but did not undergo UED (group 2). Thirty-one patients did not undergo either LED or UED (group 3). Seven men and eight women had no documented source of PE on UED and LED (group 4). Ten of 15 patients in group 4 had a documented malignancy listed as one of their diagnoses. Because patients in groups 2 and 3 did not undergo complete duplex studies, we excluded them from our analysis. We then reviewed the discharge summaries of patients in groups 1 and 4. There was no statistically significant difference in age and gender distribution, size and location of PE, critical illness, smoking status, cardiovascular disease, trauma, and in-hospital mortality between patients in group 1 and 4. Patients in group 4 had a statistically significant increased prevalence of malignancy (67% vs. 40%, P = 0.046). Patients in group 4 also had a higher percentage of active cancer than those in group 1 (47% vs. 24%, P = 0.084), although not statistically significant. We defined active cancer as either a metastatic disease or a malignancy diagnosed shortly before or after the diagnosis of PE. Patients who were undergoing treatment for cancer at the time of diagnosis of PE were also considered to have active cancer. CONCLUSION: We demonstrated a statistically significant increased prevalence of malignancy in patients with PE without DVT. However, pathophysiology and clinical significance are the aspects that remain to be understood after accrual of more patients and further research. Possibilities such as de novo thrombosis of pulmonary arteries, complete dislodgement of thrombi from peripheral veins, or false-negative venous duplex need to be explored.

In this study, we noted the common risk factors with atherosclerosis and chronic renal disease. We, therefore, hypothesized that the placement of a dialysis catheter would be a useful marker in identifying populations at increased risk of vascular disease (carotid, renal, and aortic). To further explore this issue, we examined the results of duplex scanning of the carotid arteries and aortorenal arteries in patients undergoing dialysis catheter placement. Over 49 months, each of the 123 patients who underwent permanent tunneled dialysis catheter placement received a carotid duplex study. Twelve patients (9.8%) had >/= 60% stenosis and 8 patients (6.5%) had 70% to 99% stenosis. Furthermore, 109 patients who underwent a aortorenal artery duplex study were also analyzed. The study population demonstrated a prevalence rate of 3.7% for abdominal aorta aneurysm (AAA) and 4.6% for renal artery stenosis (RAS). Based upon these data, we suggest performing routine carotid duplex scans in patients who will also receive dialysis catheter placement. However, the data did not support routine screening of AAA or RAS.