Impact of activated protein C resistance on general vascular surgical patients

Purpose: The prevalence of activated protein C resistance (APCR) and associated thrombotic morbidity among patients who undergo arterial reconstruction were investigated.Methods: Preoperative assays for functional APCR and factor V (Leiden) mutation were performed on 262 patients who underwent arterial reconstructions that consisted of cerebrovascular surgery (109), aortic or iliofemoral procedures (76), or infrainguinal bypass procedures (77). Patients were monitored for thrombotic complications during the postoperative period.Results: Depending on the stringency of the definition used, functional APCR was detected in 10.6% to 22.0% of patients tested. Factor V (Leiden) was found in 5.3% of patients. Thrombotic morbidity consisting of myocardial infarction, cerebrovascular event, or graft thrombosis occurred in 9.9% of patients, who were followed-up for a mean of 4.8 months. No significant overall correlations were found between APCR and thrombotic morbidity. Subgroup analysis revealed significant associations between functional APCR and total early postoperative thrombotic complications and early graft failure, and between factor V (Leiden) and early cerebrovascular events and late graft thrombosis (p < 0.03).Conclusions: Functional APCR is somewhat more prevalent among general vascular surgical patients than in the general population, but factor V (Leiden) is no more prevalent. APCR is not a prominent cause of thrombotic morbidity in contemporary vascular surgery. Nonetheless, it is a sufficiently important potential contributor to morbidity among some subgroups to warrant selective testing and directed therapy pending further study. (J Vasc Surg 1997;25:1054-60.)     

Evaluation of loose bodies in the elbow with MR imaging

The evaluation of loose bodies in the elbow is usually done by means of clinical examination, radiography, and postarthrographic computed tomography (CT). The authors review their experience with magnetic resonance (MR) imaging in place of postarthrographic CT for the evaluation of loose bodies in the elbow. The prospective interpretation of MR studies of the elbow in 20 patients was compared with arthroscopic findings. All elbows were imaged in multiple planes with thin sections, surface coils, and combinations of T1, T2, and proton-density weighting. The sensitivity for showing loose bodies with MR imaging was 100%, and the specificity was 67%. Because this was a nonblinded study, the results are biased and caution must be used when extrapolating these results to the general population. In this limited experience, MR imaging has reliably shown loose bodies in the elbow, and in the authors' institutions has replaced postarthrographic CT for that purpose.     

105Changes in Nitric Oxide Levels After Deep Dermal injury in the Female,Red Duroc Pig (FRDP)

Introduction : Hypertrophic scar is a devastating sequel to burns and other tangential skin injuries. It follows deep dermal injuries and does not occur after superficial injuries. Nitric oxide (NO) plays many important roles in wound healing from inflammation to scar remodeling. Studies have shown that expression of nitric oxide synthase and nitric oxide production are decreased in human hypertrophic scar. However little is known about NO involvement in the early stages of hypertrophic scarring, because of the lack of an animal model. It was recently reported that the female red Duroc pig (FRDP) makes thick scar, which is similar to human hypertrophic scar. We hypothesized that NO production in wounds on the female, red Duroc pig is similar to that of human hypertrophic scar and that NO involvement in deep wounds is different from that in superficial wounds. Methods : Superficial (0.015” to 0.030”) and deep (0.045” to 0.060”) wounds were created on the backs of four FRDPs. Biopsies were collected at weeks 1.5, 4, 8 and 21 post wounding including samples of uninjured skin. Nitric oxide levels were measured with the Griess reaction assay and normalized with tissue protein level. Results : Superficial wounds healed with an invisible scar whereas the deep wounds healed with scar resembling mild hypertrophic scar. The thickness of the scars from the deep wounds was significantly greater than uninjured skin and healed superficial wounds (p < 0.01). NO levels were increased at 1.5 weeks in deep wounds compared to superficial wounds and uninjured skin (p < 0.05). At 8 weeks, NO levels in deep wounds had returned to the level of uninjured tissue and superficial wounds. By 21 weeks, NO levels had decreased significantly when compared to superficial wounds (p < 0.01). There were no differences in NO levels between uninjured skin and superficial wounds at any time point (p > 0.05). Conclusions : NO production is similar in late, deep wounds on the female, red Duroc pig to that reported in the literature for human hypertrophic scar further validating this animal model. NO production is quite different after deep wounds as compared to superficial wounds in the FRDP. Early elevation in nitric oxide production might account for excessive inflammation in deep wounds that become thick scars in the FRDP. Nitric oxide regulators and effects at early stages of scar formation should be elucidated further and the FRDP appears to be a useful model.     

Relationship between morphology and functional ability of regenerated corneal endothelium

Cat corneal endothelium was damaged by a methylmethacrylate segment introduced into the anterior chamber. Within 3 to 6 months after each such operation the endothelial cell density (ECD) diminished, ranging from 1933 to as low as 450 (78% to 16%, respectively, of its preoperative value [PV]). Decrease in the ECD to between 1050 and 1150 (40%-45% of PV) made no impact on the corneal thickness (group 1: "non-swollen" corneas); further decrease was followed by an increase of the corneal thickness to a level of 11.5%-73.5% more than its preoperative value (group 2: "swollen" corneas). The coefficient of variation of ECD increased in both groups. The number of hexagonal endothelial cells diminished, while cells with three or nine or more facets appeared. All these changes were much more pronounced and verifiable in the group 2 corneas, which were distinguished by the appearance of giant endothelial cells, 2957-4095 micron2, ie, 7.5-13.5 times larger than the cells of undamaged endothelium. These data appear to indicate that the decrease of ECD to 1050 to 1150 (40% to 45% of its PV) does not provoke decompensation of the dehydrative function of the endothelium, whereas further decrease does provoke such decompensation, the giant endothelial cells probably being the main factor in this phenomenon.     

Oral session 42—Motor neuron disease (3)

Oral Sessions

Oral session 42—Motor neuron disease (3)     

Physical symptoms and depressive symptoms among individuals with HIV infection.

The authors investigate the importance of physical symptoms as a correlate of depressive symptoms and suicidal thoughts in a large (N = 881) community-based sample of persons infected with human immunodeficiency virus. The study overcomes limitations of prior research by minimizing overlap in measures of affective and physical symptoms, studying a more diverse population, and including correlates such as measures of social support, function, employment, insurance coverage, and cognitive impairment in the analysis. The authors' data support the notion that in diagnosing depression in the medically ill, concern over isolating physical symptoms as either "affective" or "physical" may be exaggerated.     

Comparison of descending phlebography with quantitative photoplethysmography, air plethysmography, and duplex quantitative valve closure time in assessing deep venous reflux.

To assess the role of noninvasive tests--quantitative photoplethysmography, air plethysmography, and quantitative duplex scanning, we compared a group of normal (group N, eight limbs) volunteers to patients with severe chronic venous insufficiency who were stratified according to the degree of reflux seen on the current "gold standard," descending phlebography. Group M (10 limbs) had mild (grades 0 to 2) reflux, and group S (10 limbs) had severe (grades 3 to 4) reflux as determined by phlebography. Quantitative photoplethysmography could identify normal from abnormal limbs but could not distinguish the severity of reflux. Air plethysmography was used to calculate venous filling index, ejection fraction, and residual volume fraction. Ejection fraction was the same in all groups. Venous filling index could not significantly distinguish the degree of reflux (group M vs group S) but increased as reflux increased. Residual volume fraction was considerably higher in group S. Quantitative duplex valve closure time was measured in the superficial femoral and popliteal veins, with the values added together in each limb to give a total valve closure time (TVCT). A TVCT value greater than or equal to 4 seconds correlated best with severe phlebographic reflux, with a sensitivity of 90%, a specificity of 94%, and an accuracy of 93%. This value was confirmed as the best test for venous reflux by receiver operating characteristic curve analysis. Thus in the evaluation of patients with severe chronic venous insufficiency who are candidates for phlebography and surgery, quantitative duplex measurement of TVCT gives the best noninvasive assessment of the severity of deep venous reflux.