Improved outcomes with endovascular stent grafts for thoracic aorta transections.

OBJECTIVE: To retrospectively assess the outcome of endovascular stent-graft implantation for thoracic aortic transections (ETAT). DESIGN: Retrospective review. METHODS: 16 patients median age 30 years, treated between May 2000 and April 2007. Median injury severity score was 33 (range 29 to 66) in 14 acute patients; 2 patients had thoracic pseudoaneurysms. The Cook-Zenith endograft was used in eight patients, Medtronic-Talent (6) and Gore-Excluder (2). Average procedure time was 90 minutes, blood loss 100 (range 40 to 3000) mls, screening time 10.8 (range 5.9 to 22.6) minutes, and contrast dose was 195 (range 60 to 400) mls. RESULTS: Graft deployment was successful in all cases. There was one death within 30 days. The left subclavian artery was completely covered in one case, and partially in three. Two patients had Type I endoleak, and one delayed Type II endoleak. One patient had iatrogenic right coronary artery dissection. Two patients developed difficult to treat hypertension, and one acute renal failure. CONCLUSION: Endovascular intervention is a safe and effective treatment for aortic transection in multiple trauma patients. ETAT reduces the major morbidity and mortality associated with open repair in multiple trauma patients. The majority of these patients are young and long-term follow up is necessary to assess graft durability.

Partial purification and characterization of a triacylglycerol-transfer protein from rabbit serum.

Rabbit lipoprotein-free serum was found to contain a protein fraction that mediates the transfer of [3H]triacylglycerol from low-density lipoprotein to high-density lipoprotein. Fractionation of rabbit lipoprotein-free serum by DEAE-Sephadex chromatography, ammonium sulphate precipitation, concanavalin-A-Sepharose chromatography, Sephadex G-200 gel filtration, phenyl-Sepharose chromatography and Sephadex G-100 gel filtration, yielded a preparation that had a 500-fold increase in transfer activity compared to that of the starting sample. The transfer activity appeared to reside in a glycoprotein of molecular weight in the range 100 000-155 000 and an isoelectric point at pH 9.

Complications of aortic endografting.

Endovascular repair of abdominal aortic aneurysm has been shown to have a significantly lower perioperative mortality rate compared with open repair. It has been a blessing for patients at high risk who were previously denied treatment for their aortic aneurysms. It does, however, have a substantial need for re-intervention for complications. Many of these complications including endoleak, endotension, migration, post implant syndrome and conversion to open repair are unique to endovascular aneurysm repair. Others including injury to the iliac arteries, graft limb thromboses and structural failure of prostheses occur with greater frequency in endovascular repair compared with open repair. It is important, therefore, for vascular surgeons to be aware of these complications including their prevention and appropriate that patients are informed of their incidence. This review discusses the local and vascular complications of endovascular repair of abdominal aortic aneurysm with an emphasis on newer aspects.

The enkephalins are amongst the peptides hydrolyzed by purified acetylcholinesterase.

We have shown that purified acetylcholinesterase has the ability to hydrolyze a number of peptides including the physiologically occurring enkephalins. The enkephalins lost both the amino- and carboxyl-terminal amino acids, but several other peptides were not degraded. The enzyme was purified using an affinity chromatographic matrix that recognised one component of the active centre that is specific to cholinesterases, the anionic-binding site. The acetylcholinesterase was extracted from four tissues of diverse origin to minimise the risk of co-purifying a peptidase. The enzyme was essentially homogeneous on polyacrylamide gels, and there was only one protein that bound diisopropylfluorophosphate in the samples. The peptidase activity was not affected by the aminopeptidase inhibitor puromycin, but it was inhibited by acetylcholine at concentrations that also reduced the esterase activity. It was concluded that acetylcholinesterase also has the capacity for a novel type of hydrolysis of peptide bonds. The ability of acetylcholinesterase to hydrolyse naturally occurring compounds of different chemical nature, like esters and peptides, may help explain the long-standing puzzle of why the enzyme is more widely distributed than acetylcholine, once thought to be its sole natural substrate. The localization of the enzyme probably more accurately reflects the distribution of all its substrates, although their identity remains to be determined.

Evaluation of an enzymatic method for determining creatinine in plasma.

An enzymatic kit method for the determination of plasma creatinine was optimised for use with a centrifugal analyser and its performance characteristics and practicability compared with an end point and a kinetic Jaffé-based method. The enzymatic method exhibited several advantages over Jaffé-based methods--namely, smaller sample size, rapid sample throughput (200 per hour), and improved specificity. Glucose, acetoacetate, and cefoxitin did not interfere with the enzymatic method, although bilirubin did cause a negative interference which depended on both creatinine and bilirubin concentrations. The enzymatic method has particular clinical application in neonates, diabetic ketotic patients, and those receiving cephalosporins.

Quantitative method for determining serum alkaline phosphatase isoenzyme activity: estimation of intestinal component.

Intestinal alkaline phosphatase activity was measured using levamisole inhibition, and results were compared with a previously reported method using L-phenylalanine. Sixty two per cent intestinal, 39% placental, and 1.3% of either bone or liver alkaline phosphatase activity remained when alkaline phosphatase activity was inhibited in a 2-amino-2-methyl-1-propanol (AMP) buffer reagent system with 10 mmol/l levamisole (final assay concentration 8.1 mmol/l). The assay imprecision (SD) was 0.6 U/l compared with 3.9 U/l using L-phenylalanine for specimens with total alkaline phosphatase activity less than 250 U/l (reference range 30-120 U/l). In serum pools with raised total alkaline phosphatase activity errors in recovered intestinal activity were small (usually less than 3 U/l) when intestinal alkaline phosphatase was added. Much larger errors and many underestimated results were found using L-phenylalanine. For non-haemolysed specimens it is concluded that an assay based on levamisole inhibition provides a better measure of intestinal alkaline phosphatase activity than L-phenylalanine.

Exertional disruption of axillofemoral graft anastomosis. 'The axillary pullout syndrome'.

Five cases of exertional disruption of the axillary anastomosis occurred at intervals of 13 to 30 days after axillofemoral polytef (polytetrafluoroethylene [PTFE]) graft insertion. Graft evulsion was preceded by effort and heralded by axillary pain, an expanding hematoma, and a pseudoaneurysm formation. Proximal control of the subclavian artery by a supraclavicular approach or balloon allowed safe wound exploration. Successful reconstruction required lengthening of the graft or replacement. Secondary disruption occurred with simple repair. Although temporary postoperative brachial plexus neuropathy was common, no significant hand ischemia was noted. Twenty-two reports of axillary anastomotic disruption were made to the Food and Drug Administration, Washington, DC, during a 2-year period, and one manufacturer of polytef grafts provided data on 10 reports received throughout 7 years. Surface anatomy measurements in 20 control patients demonstrated that arm abduction and lateral flexion of the body increased the distance between the axillary and femoral arteries by a mean of 15.5%. Similar measurements taken from the proximal axillary artery showed a mean length increase of less than 10%. This complication may be avoided by inserting the polytef graft with several centimeters of excess length and positioning the axillary anastomosis medial to the pectoralis minor muscle.

Management strategy of complex extremity injuries.

In this retrospective review of 37 patients with combined orthopedic and vascular injuries, our management strategy emphasized the prompt recognition of limb threat. Twenty-two patients had lower-extremity and 15 had upper-extremity injuries. No deaths occurred. Five delayed amputations were performed for limbs left denervated by associated soft tissue or neural injuries. No late vascular insufficiency was recorded in patients who underwent reconstruction with autogenous tissue. Whenever possible, the precise site of vascular injury was identified angiographically to help plan an approach that would provide adequate exposure for vessel repair as well as orthopedic stabilization. Vascular reconstruction typically preceded osseous stabilization. We conclude that improved outcome requires a coordinated multidisciplinary approach, expeditious limb revascularization, fasciotomy as indicated, rapid fixation of osseous injuries, and adequate soft tissue coverage of the underlying repair.

Does intraoperative hepatic ultrasonography change surgical decision making during liver resection?

BACKGROUND: Intraoperative hepatic ultrasonography (IOUS) has been used to accurately identify and localize hepatic tumors as an adjunct to hepatic resection and for the detection of occult liver metastases during primary resection of other gastrointestinal carcinomas. The face validity of IOUS to identify more lesions than conventional diagnostic modalities and the content validity of IOUS to change the planned surgical management has been assessed in a blinded, prospective manner. METHODS: Sixty-two patients were studied at two institutions by one surgeon. IOUS was compared with computed tomography (CT) angioportography in 30 patients undergoing planned hepatic resection (19 metastatic, 11 primary) and with conventional hepatic ultrasonography (+/- venous enhanced CT scan) in 32 patients undergoing primary excision of gastrointestinal carcinomas. RESULTS: Twenty of the 30 hepatic resections (67%) were changed or guided by IOUS as determined by the operating surgeon at the completion of the laparotomy. IOUS detected 26 more metastases (44%) in 10 of 19 patients (1 to 5 per patient). Two patients had preoperatively suspected metastases refuted by IOUS-guided biopsy. Eight of the 11 patients (73%) undergoing resection of primary carcinoma of the liver had the planned procedure changed or guided by IOUS. This included four hepatocellular carcinomas with more extensive involvement at the confluence of the hepatic veins and the inferior vena cava, necessitating resection with the aid of total vascular isolation. In 32 patients undergoing primary resection of gastrointestinal carcinomas, 5 patients (16%) had the stage of disease altered by IOUS when compared with conventional ultrasound (+/- venous enhanced CT scan). CONCLUSIONS: The validity of IOUS is good. IOUS guided the intraoperative surgical management of two thirds of the patients undergoing hepatic resection when compared with CT angioportography. Intraoperative hepatic ultrasonography using a reproducible systematic approach can change the clinical management of patients undergoing hepatic resection for malignancy.

Cardiac risk index as a predictor of long-term survival after repair of abdominal aortic aneurysm.

Life expectancy after aneurysm surgery was analyzed for male patients over the age of 60 years with known risk factors classified by the Goldman cardiac risk index, which has previously been utilized for prediction of immediate perioperative risks of surgery and anesthesia. The preoperative risk factors, Goldman cardiac risk index, and long-term survival rates were tabulated for each of 96 male patients over the age of 60 years who had elective repair of infrarenal abdominal aortic aneurysm. Follow-up data of up to 14 years (mean 4.2 years) was entered into a SurvPak-PC biostatistical software program for construction of Kaplan-Meier survival curves and actuarial life tables to measure differences in survival between groups and for performance of nonparametric analysis (by log rank test) of the influence of preoperative risk factors. The operative mortality rate was 3.1 percent and the 5 year survival rate for the whole group was 61 percent, with a median survival of 8.7 years. Five year survival rates for patients in three age groups (60 to 70 years, 71 to 80 years, and greater than 80 years), when compared with age-matched populations, were 67 percent versus 88 percent, 50 percent versus 73 percent, and 35 percent versus 39 percent, respectively. Patients in Goldman class 1, 2, and 3 or 4 had 5 year survival rates of 79 percent, 53 percent, and 41 percent, respectively. Factors that adversely affected long-term survival were Goldman classes 3 or 4 (median survival 2.1 +/- 0.4 years, p = 0.001), cerebrovascular disease (median survival 1.9 +/- 0.6 years, p = 0.004), history of cardiac disease (median survival 3.2 +/- 0.6 years, p = 0.012), and creatinine concentration greater than 3 mg/100 ml (median survival 3.1 +/- 1.6 years, p = 0.034), whereas Goldman class 2 or the presence of hypertension, pulmonary disease, diabetes mellitus, peripheral vascular disease, and size of the aneurysm, although associated with a shortened length of survival, as independent variables did not reach statistical significance. A combination of any three of these risk factors, however, shortened the survival time markedly (median 1.9 +/- 0.7 years, p = 0.003). We believe that the Goldman cardiac risk index classification correlates with long-term survival in patients undergoing elective aortic surgery.

Experimental and clinical applications of angioscopic guidance for laser angioplasty.

The role of angioscopic monitoring and aiming for control of laser intervention in the vascular system was initially investigated in 48 vessels in 33 dogs, and the techniques were then applied to 30 patients undergoing intraoperative or percutaneous laser-probe angioplasty treatment for long atherosclerotic occlusions of the femoral and popliteal arteries or well-localized lesions of the superficial femoral artery. Experimental bare argon fiber laser application in 20 normal canine arteries in vivo demonstrated that small-diameter laser fibers could be accurately aimed by manipulations of the scope. However, advancement of the fiber resulted universally in perforation, with extravasation and thermal damage of surrounding tissues after 2 seconds of argon laser energy at low power. In 28 canine and 2 human veins, angioscopically guided metallic-tipped laserprobes were used to divide 82 valve cusps in preparation for in-situ bypass, with satisfactory aiming and monitoring achieved expeditiously by manipulations of the angioscope. We conclude that angioscopic aiming of lasers is feasible in normal vessels or localized lesions. In contrast, angioscopy has a restricted role for guidance of laser angioplasty in atherosclerotic, occluded arteries, and does not prevent perforation. Postprocedural inspection allows immediate detection of complications and may avert or predict poor outcome.

A new classification of hepatic territories using intraoperative ultrasound.

Intraoperative ultrasonography is now established as the most accurate technique for detecting and localizing hepatic tumors, be they primary or metastatic. A major problem is the accurate placement of any lesions found by intraoperative ultrasound and, hence, the correlation of the lesions found by ultrasound to the current classification of hepatic segments and to lesions seen by other imaging techniques. This paper outlines an objective and reproducible method of mapping hepatic lesions into territories defined solely by the major hepatic veins and their tributaries. It is a simple technique that can be readily used by any surgeon, which accurately determines the presence, number, size, and site of hepatic metastases.

Pathogenesis determines late morbidity of axillosubclavian vein thrombosis.

The late consequences of axillosubclavian vein thrombosis were evaluated through a clinical follow-up of 41 patients (45 limbs) treated from July 1975 to December 1985. The causes of the obstruction were classified into two main groups: Intrinsic damage, consisting of thrombophlebitis due to intravenous drug abuse (11 patients), central venous catheterization (10 patients), and hypercoagulability state (2 patients); and extrinsic obstruction, involving effort-induced or thoracic outlet obstruction (9 patients), underlying neoplastic disease (5 patients), trauma (3 patients), and congenital venous malformation (1 patient). Clinical diagnosis was confirmed by upper arm venography in all 41 patients, and all were initially treated by anticoagulation with heparin for 1 to 2 weeks, usually followed by oral warfarin for a variable period of 1 week to 5 years. Only three patients had an operation (rib resection for thoracic outlet obstruction, thrombectomy and clavicle fixation, and repair of a congenital venous malformation). Major early morbidity consisted of a documented pulmonary embolus in five patients, two in Group I and three in Group II, for an overall incidence of 12 percent. Clinical follow-up of up to 5 years revealed that chronic morbidity was related to our classification. Thrombosis secondary to intrinsic damage rarely caused persistent symptoms and responded well to anticoagulation alone. Conversely, when extrinsic obstruction was the cause, only 50 percent of patients were symptom-free, whereas many had disabling intermittent arm swelling and pain. Repeat venography in severely symptomatic patients revealed persistent obstruction with no recanalization. We conclude that patients with axillosubclavian venous thrombosis due to intrinsic damage do not require treatment other than anticoagulants, whereas patients with extrinsic obstruction often have poor long-term results from conventional therapy and therefore should be considered for adjunctive treatment with thrombolysins or operative intervention.

Angioscopy.

Endoscopy of the vascular system has evolved over recent years from an experimental procedure to a sophisticated diagnostic and therapeutic technique for surgical or percutaneous interventions of the peripheral vascular system. Particularly in procedures involving remote instrumentation of arteries, the angioscope provides a method of controlled guidance and a monitor of the effects of the various instruments on the vessel wall and allows immediate assessment of results. Angioscopic examination reveals the extent of intimal injury after angioplasty, in situ vein preparation, trauma, and thrombectomy and gives insights into the mechanisms and effects of endovascular devices.

Devices for aortic aneurysm repair.

Although the technical success and short-term efficacy of endovascular grafts have now been demonstrated, the long-term durability of grafts used in the aorta remains to be proven. No long-term data are yet available regarding device durability or patient outcome beyond the initial few years. Recent evidence shows that the ability of endovascular grafts to cause shrinkage and regression of aortic aneurysms may have a paradoxic effect of distorting the endograft itself, thus causing geometric changes within the supporting metallic framework and, ultimately, device failure (Fig. 9). Thus, the desired positive effect of the device may, ironically, lead to its eventual failure.

Relative diagnostic value of serum non-SHBG-bound testosterone, free androgen index and free testosterone in the assessment of mild to moderate hirsutism.

Recent evidence suggests that steroid hormone loosely bound to albumin is available for target-cell entry. Preliminary studies have suggested that a measure of this fraction, non-sex-hormone-binding globulin-bound testosterone (NSB-T), provides the best in vitro diagnostic test for idiopathic hirsutism. We compared the diagnostic value of NSB-T, total testosterone (T), free testosterone (fT), and the free androgen index (FAI) in supporting the clinical diagnosis in 22 pre-menopausal women with hirsutism. NSB-T supported the diagnosis in 50% of cases, compared with 23% for T, 55% for fT by analogue RIA, and 68% for FAI. We conclude that in mild to moderate hirsutism the measurement of NSB-T does not yield diagnostic information addition to that provided by the FAI.

Variation in plasma apolipoprotein A-1 and B concentrations following myocardial infarction.

Measurements of plasma apolipoprotein A-1 and B concentrations are increasingly used for the laboratory assessment of risk of coronary artery disease (CAD). This study of 22 patients investigated the response of plasma apolipoprotein A-1 and B levels for up to 20 days following a myocardial infarction. Seven of these patients participated in a clinical trial using the drug Tissue Plasminogen Activator (TPA). We established that, unlike many other plasma proteins, apolipoproteins do not display a classic acute phase response following myocardial infarction, although large variations in plasma apolipoprotein levels were observed in the patients investigated. Our studies also show that the measurement of plasma apolipoproteins A-1 and B to assess future CAD risk in myocardial infarction patients should be deferred for a minimum of at least 14 days post-infarction. No significant difference was observed in the pattern of apolipoprotein response between patients receiving TPA and those not given this drug.

Early and late conversion from endoluminal to open repair.

Conversion from endoluminal to open repair of abdominal aortic aneurysms (AAA) may be primary, at the original operation or secondary, at a subsequent operation. The indications for primary conversion include aortic rupture and migration of an endograft resulting in obstructed blood flow and irreversible twisting of an endograft. The indications for secondary conversion include persistent endoleak, sealed endoleak with continued AAA expansion, apparently successful AAA repair, with continued expansion and the presence of an infected endograft. The technique of conversion varies from standard repair through modified standard repair to supraceliac control, depending on the cause of failure leading to conversion. All conversion procedures expose the patient to an increased risk and are best avoided by careful case selection, accurate sizing, and good procedural technique.

Endoluminal repair of abdominal aortic aneurysms - state of the art.

This paper considers the historical aspects of endovascular aneursym repair; the major findings of our Departments experience over an 812-year period and reviews recent developments in endovascular prostheses. Analysis of 400 patients undergoing primary repair of abdominal aortic aneurysm between 1992 and 2000 revealed a perioperative mortality rate of 2.7% and primary conversion rate of 5%. With sequential studies it was shown that the outcome was better with bifurcated/aorto uni iliac grafts than tube grafts; better with second generation prostheses than first generation protheses and that survival in consecutive patients treated concurrently by open repair and endoluminal repair was superior in the endoluminal group. Endoluminal AAA repair is at a critical point of its development. It is unquestioned that it can dramatically reduce the need for intensive care and length of hospital stay and more recently it has been reported that survival is improved compared with open repair. The need for lifetime surveillance, the probability of graft failure and need for re-intervention, however, negate some of the advantages. The small incidence of unpredictable rupture following endoluminal AAA repair is a timely reminder of the need for continued careful follow-up.

Iatrogenic vascular trauma associated with intra-aortic balloon pumping: identification of risk factors.

The most important noncardiac consequence of use of the intra-aortic balloon pump (IABP) is associated iatrogenic vascular trauma. A retrospective analysis was undertaken of all patients at our institution (n = 90, mean age 60 years) who had insertion of an IABP over a 10-year period to assess the possibility of preoperative identification of patients at high risk of IABP associated vascular injury. Catheters were introduced via the common femoral artery (n = 84; 30 percutaneous, 4 open Seldinger technique, 50 via a dacron sleeve), external iliac artery (n = 2), and ascending aorta (n = 4). Thirty patients (33.3%) developed one or more complications, with 25 vascular complications, six major septic complications, and four deaths. Variables identified as significant risk factors for IABP complications were female gender (P < 0.01) and concomitant peripheral vascular disease (P < 0.05). Site of insertion, method or difficulty of insertion, age, duration of counterpulsation, and use of anticoagulation and antibiotics did not significantly affect the incidence of vascular complications (P > 0.05). In conclusion, prior to cardiac surgery, we recommend screening for peripheral vascular disease to identify patients at increased risk of complications should IABP counterpulsation be required. Ankle/brachial systolic pressure indices may be used to detect subclinical disease.