Predicting failure in polytetrafluoroethylene vascular access grafts for hemodialysis: a pilot study

In order to determine if serial, noninvasive evaluation of polytetrafluoroethylene (PTFE) vascular access grafts could identify a subgroup of patients at risk for thrombosis, the authors studied flow characteristics, using duplex ultrasonic scanning, in 18 hemodialysis patients with forearm loop grafts. On average, five examinations were performed per patient over the 10-month study period. Seven episodes of thrombosis occurred in six patients. The mean Doppler flow in grafts that subsequently thrombosed was significantly lower than in those that did not (544 +/- 218 ml/min versus 843 +/- 391 ml/min, p less than 0.001). The interval from last examination to thrombosis ranged from 13 to 58 days. At a defined cut-off flow of 450 ml/min, this test yielded a sensitivity of 83% and a specificity of 75% for episodes of thrombosis occurring within 2 to 6 weeks. The authors conclude that episodes of thrombosis in PTFE arm loop grafts are usually preceded by significantly lower Doppler-measured flow than grafts that do not thrombose and that it may be possible, by this means, to identify grafts at risk.     

Magenkarzinom – eine Infektionskrankheit

Gastric cancer still represents the second most common cause of gastrointestinal cancers in Germany. A disturbing issue is that at the time of diagnosis there are less than 15% of patients for whom a cure can be achieved. Nowadays, biological, histomorphological, molecular genetic and epidemiological data suggest that Helicobacter pylori eradication may lead to the prevention of gastric pre-neoplastic lesions and even gastric cancer. At present, eradication can be offered to selected patients and populations at increased risk, but more research is required before embarking on general and global H. pylori eradication for gastric cancer prevention. The main challenge is to determine how long mucosal abnormalities remain reversible and gastric cancer development can be halted.     

Coronary artery and saphenous vein graft remodeling: A review of histologic findings after various interventional procedures—part V

Catheter balloon angioplasty is a well accepted form of nonsurgical treatment of acutely and chronically obstructed coronary artery vessels. It is also the centerpiece for various new intervention techniques. Their morphologic effect on the site of obstruction has been termed “remodeling.” Part V of this six-part series focuses on remodeling effects of balloon angioplasty on obstructed young (≤ 1 year) and old (> 1 year) saphenous vein bypass grafts.     

Retention of "safe" blood donors. The Retrovirus Epidemiology Donor Study

BACKGROUND: There are obvious advantages to increasing donor retention. However, for reasons of blood safety, certain donors may, in fact, be more desirable to retain than others. “Safe” donors are defined as those who provided a blood donation that was negative on all laboratory screening tests and who subsequently reported no behavioral risks in response to an anonymous survey. This study identifies the most important factors affecting the intention of “safe” donors to provide another donation. STUDY DESIGN AND METHODS: An anonymous survey asking about donation history, sexual history, injecting drug use, and recent donation experience was mailed to 50,162 randomly selected allogeneic donors (including directed donors) who gave blood from April through July or from October through December 1993 at one of the five United States blood centers participating in the Retrovirus Epidemiology Donor Study. Before mailing, questionnaires were coded to designate donors with nonreactive laboratory screening tests at their most recent donation. RESULTS: A total of 34,726 donors (69%) responded, with substantially higher response among repeat donors. According to reported intentions only, the vast majority of “safe” donors indicated a high likelihood of donating again within the next 12 months. Only 3.4 percent reported a low likelihood of donating again. A comparison of those likely to return and those unlikely to return reveals significant differences in demographics and in ratings of the donation experience. A higher proportion of those unlikely to return were first-time donors, minority-group donors, and donors with less education. The highest projected loss among “safe” donors was seen for those who gave a fair to poor assessment of their treatment by blood center staff or of their physical well-being during or after donating. CONCLUSION: These data suggest that efforts to improve donors' perceptions of their donation experience, as well as attention to the physical effects of blood donation, may aid in the retention of both repeat and first-time donors.     

Vein patch versus primary closure for carotid endarterectomy. A randomized prospective study in a selected group of patients

During a 4-year period, 136 patients undergoing 152 carotid endarterectomies consented to be randomized to primary or saphenous vein patch closure of the arteriotomy. At operation, before randomization, careful assessment of arterial dimensions and anatomy was made. Patients who had an internal carotid artery (ICA) diameter less than 5 mm, arteriotomy extending more than 3 cm beyond the origin of the ICA, or tortuous or kinked ICAs were not randomized; they received obligatory vein patch closure (necessary in 20% cases). All patients were followed up every 3 months for 1 year and every 6 months thereafter with duplex scanning, ocular pneumoplethysmography, and neurologic assessment. The incidence of atherosclerotic risk factors was equal in the groups and all except one of the patients were male. Perioperative morbidity was not significantly different among those having primary closure (n = 60), saphenous vein patch closure (n = 62), and obligatory vein patch closure (n = 30). Operative time among patients having primary closure (122 +/- 4 minutes) was significantly less (p less than 0.001) than among those having saphenous vein patch closure (150 +/- 3 minutes). Three perioperative strokes were evenly distributed among the groups (2% for all procedures); no deaths and no acute postoperative occlusions occurred. Recurrent disease occurred in 12.9% of patients having saphenous vein patch closure compared with its occurrence in 1.7% of those having primary closure (p less than 0.05). However, most recurrences were moderate stenoses (25% to 50% diameter reduction), all were smooth-surfaced, and none required a second operation. All except one of the recurrences among those patients with saphenous vein patch closure were in the bulb and the origin of the ICA; two had evidence of regression. This finding suggested that thrombus layering in the dilated part of the saphenous vein patch reconstruction was the cause. This study demonstrates that in men with carotid arteries of predetermined minimal dimensions undergoing carotid endarterectomy routine saphenous vein patch closure does not produce superior results, is associated with a higher incidence of early recurrence, and increases operative time. In selected patients with anatomic risk factors for recurrent disease or acute postoperative occlusion, saphenous vein patch closure is appropriate.