Effects of angiographic needle size and subsequent catheter insertion on arterial walls. An in vitro experiment in human cadavers.

RATIONALE AND OBJECTIVES: It is widely believed that down-sizing catheters, and possibly needles, will decrease damage to the entry vessel in the performance of angiography. The purposes of this in vitro experiment are to determine if smaller needles produce less arterial wall damage than larger needles and to assess the influence of subsequent catheter insertion. METHODS: Each iliac artery pair from 35 fresh human cadavers was punctured three times with an 18-g needle and three times with a 21-g needle, for a total of 210 punctures. In two of each set of three, a 5- or 7-F dilator was passed. One hundred ninety-eight puncture tracts were usable and examined microscopically. They were graded on a scale of 1 to 3 in each of four categories: size of tract, margin irregularity, approximation of edges, and shape of tract. RESULTS: Chi-square analysis of the grading scores showed a significant shift of cases into lower damage grades when the smaller gauge needle was used for initial punctures (P < .0005). The subsequent insertion of a dilator, however, imposed further damage, such that the initial differences due to needle gauge were obliterated (P > .2). CONCLUSION: These data indicate that a 21-g needle produces less arterial wall damage than an 18-g needle, but that any safety conferred by the smaller needle is eliminated by the subsequent insertion of a 5- or 7-F catheter.

Availability and selection of donors for pediatric heart transplantation.

METHODS: Applying generally accepted criteria for selection of adult heart donors, we conducted a retrospective study of brain-dead infants and children for assessment of suitability as donors for heart transplantation. Cardiac histopathologic studies were evaluated in all subjects undergoing autopsy. RESULTS: In 5 years there were 58 such patients, the majority of whom had head injury, near-drowning, near-miss sudden infant death syndrome, infection, or asphyxia. Of these, only five met the proposed clinical criteria. Most prospective donors were eliminated on the basis of prolonged cardiac arrest (n = 33), pressor dependency (n = 25), and/or infection (n = 10). Forty-two subjects underwent autopsy, of whom 36 would not have been excluded as donors except on the basis of ischemic cardiac insult. Of these, 18 subjects were found to have essentially normal myocardium, nine had abnormal but potentially reversible microscopic changes, and nine had myocardial infarction. The pathologic findings were not predicted by the selection criteria, but severe chest trauma was not associated with infarction, eight of the nine patients with infarction had had cardiac arrest, and most of those with infarction had drowned or had had sudden infant death syndrome. CONCLUSIONS: The supply of donor organs for pediatric heart transplantation is very limited if selection criteria used for adult donors are applied. These criteria, however, do not correlate well with myocardial pathologic findings in infants and children. More accurate predictors of donor suitability are needed.

A new concept for anastomosis of the fallopian tube: tissue reconstruction with nonpenetrating, arcuate, legged clips in the rat model.

OBJECTIVE: To evaluate the titanium Kirsch-Zhu microclip microsurgical reanastomoses of the fallopian tubes. DESIGN: Compare the reanastomoses of the rat uterine horn between Kirsch-Zhu clips (Cushman Engineering, Albuquerque, NM) (group A) and conventional suture microsurgical techniques (group B). SETTING: Microsurgery Research Laboratory, Loma Linda University Medical Center, Loma Linda, California. PATIENTS, PARTICIPANTS: Fifteen SD rats Harlan (Harlan Sprague-Dawley Corp., Indianapolis, IN) were done in groups A and B and six in control group (C). MAIN OUTCOME MEASURE: Pregnancy rate, litter size, tissue of procedure, and histologic results. RESULTS: The clip technique was shorter in procedure time and resulted in equal fertility rate and litter size. Histologically, there were less granulomatous formation and histiocytic inflammation, but muscularis thinning and fibrosis were noted with the clip. CONCLUSIONS: The Kirsch-Zhu clip has potential for application to human fallopian tube reanastomoses.

Histopathologic evaluation of the canine prostate following electrovaporization.

PURPOSE: Transurethral electrovaporization of the prostate (TVP) for symptomatic benign prostatic hypertrophy (BPH) has proven to be efficacious with minimal patient morbidity. When compared to transurethral resection of the prostate (TURP), TVP demonstrates comparable postoperative flow rates, American Urologic Association (AUA) symptom score indices, and a potential cost savings. However, in the human studies it has not been possible to correlate these clinical parameters with procedure-related histopathologic changes in the prostate immediately postoperative or during wound healing. The following study was done using a canine model in an effort to evaluate these histopathologic changes. METHODS AND MATERIALS: Fifteen hounds (25-35 kg.) underwent antegrade electrovaporization of the prostate, via an open cystotomy, using a Circon ACMI USA series resectoscope and video equipment. The dogs were sacrificed and the prostates harvested at various intervals postoperatively (0-11 weeks). The prostates were evaluated grossly as well as histologically for cavitary defects, depth of necrosis, and cellular response. RESULTS: Prostates examined immediately following the procedure demonstrated superficial necrosis (less than 2 mm.) in the region of vaporized tissue. One week postoperatively, the vaporized regions demonstrated an intense acute inflammation amidst superficial necrosis with focal hemorrhage and dystrophic calcification. Transient glandular cystic changes developed, but were resolving by seven weeks postoperatively. Re-epithelialization was underway by the third postoperative week and epithelial stratification underway by the fifth week. There was no extension of the initial two millimeter zone of necrosis at any time point examined. CONCLUSION: TVP in the canine model vaporizes prostatic tissue at the site of contact. Only a shallow remnant of necrosis remains at the site of vaporization, indicating the highly localized effect of this technique. Healing at the site of vaporization occurs in a rapid and expected manner. These data provide a histopathologic rationale for the minimal morbidity and the efficacious nature of this technique demonstrated in clinical studies.

Use of angiographic needles with or without stylets: pathologic assessment of vessel walls after puncture.

There is controversy as to whether angiographic needles without stylets produce more arterial damage than those with stylets. Iliac arteries from 15 fresh human cadavers were punctured 56 times with either an 18-gauge angiographic needle with a stylet or one without a stylet (28 punctures with each needle type). These puncture sites were serially sectioned and examined microscopically. Each needle tract was evaluated for margin irregularity, shape of puncture, and approximation of edges. No statistically significant differences in arterial wall changes were found. The authors' data suggest that the choice of beveled needle use in angiography can probably be made on a basis other than concern for differences in vessel wall damage secondary to the presence or absence of a stylet.

Nonpenetrating, arcuate-legged clip reconstruction of the rat uterine horn.

A new method for reconstructing rat uterine horn was developed in which nonpenetrating, arcuate-legged clips are applied in interrupted fashion to everted seromuscular edges, forming an elastomeric flanged joint. This anastomosis has unusual physical and morphologic properties, with improved tissue healing and luminal restitution. Clipping is easier than suturing, and resulted in equivalent fertility rate (50-60%) and litter size. It also is associated with less granuloma formation and hystiocytic infiltration than suture. The new technique has the potential of endoscopic translation for human tubal reconstruction.