Anastomotic aneurysms

Immune checkpoint programmed death-1 mediates abdominal aortic aneurysm and pseudoaneurysm progression

PURPOSE

The causes and pathogenetic mechanisms underlying abdominal aortic aneurysms (AAAs) and pseudoaneurysms are not fully understood. We hypothesized that inhibiting programmed death-1 (PD-1) can decrease AAA and pseudoaneurysm formation in mouse and rat models.

METHODS

Human AAA samples were examined in conjunction with an adventitial calcium chloride (CaCl2) application mouse model and an aortic patch angioplasty rat model. Single-dose PD-1 antibody (4 mg/kg) or BMS-1 (PD-1 inhibitor-1) (1 mg/kg) was administered by intraperitoneal (IP) or intraluminal injection. In the intramural injection group, PD-1 antibody was injected after CaCl2 incubation. The rats were divided into three groups: (1) the control group was only decellularized without other special treatment, (2) the PD-1 antibody-coated patch group, and (3) the BMS-1 coated patch group. Patches implanted in the rat abdominal aorta were harvested on day 14 after implantation and analyzed.

RESULTS

Immunohistochemical analysis showed PD-1-positive cells, PD-1 and CD3, PD-1 and CD68, and PD-1 and α-actin co-expressed in the human AAA samples. Intraperitoneal (IP) injection or intraluminal injection of PD-1antibody/BMS-1 significantly inhibited AAA progression. PD-1 antibody and BMS-1 were each successfully conjugated to decellularized rat thoracic artery patches, respectively, by hyaluronic acid. Patches coated with either humanized PD-1 antibody or BMS-1 can also inhibit pseudoaneurysm progression and inflammatory cell infiltration.

CONCLUSION

PD-1 pathway inhibition may be a promising therapeutic strategy for inhibiting AAA and pseudoaneurysm progression.

Detethering the superficial temporal artery: Application to tension free superficial temporal artery-middle cerebral artery bypasses

Extracranial-intracranial bypass has been shown to be effective in the surgical treatment of moyamoya disease, complex aneurysms, and tumors that involve proximal vasculature in carefully selected patients. Branches of the superficial temporal artery (STA) are used commonly for the bypass surgery; however, an appropriate length of the donor vessel must be harvested to avoid failure secondary to anastomotic tension. The goal of this cadaveric study was to investigate quantitatively operative techniques that can increase the STA length available to facilitate tension-free STA-middle cerebral artery (MCA) bypass. We conducted a cadaveric study using a total of 16 sides in eight cadavers. Measurements of the STA trunk with its frontal branch (STAfb) were taken before and after skeletonization and detethering of the STA with the STAfb and mobilization of the parietal branch of the STA. A final measurement of the STA with the STAfb was taken for the free length gained toward visible proximal cortical branches of the MCA. Paired student's t-tests were used to compare the mean length before and after mobilization and unpaired t-tests to analyze according to laterality. The mean length of the STA with the STAfb was 9.0 cm prior to modification. After skeletonization and mobilization, the mean lengths increased significantly to 10.5 and 11.3 cm, respectively (p < 0.05). Especially in the cases that had the coiled and tortuous STA, skeletonization was considerably effective to increase the length of the STA with the STAfb. After simulating a bypass by bringing the STAfb to the recipient MCA site, the mean extended length of the STA with the STAfb was 3.0 cm. There were no statistically significant differences between sides in all measurements. We report a significant increase in the mean STA length available (3.0 cm) following skeletonization and mobilization. Clinical applications of the extended length of the STA with the STAfb may facilitate tension-free STA-MCA bypasses and improve outcomes. Further studies are needed in a clinical context.

Transforming Growth Factor-β1 Inhibits Pseudoaneurysm Formation After Aortic Patch Angioplasty

OBJECTIVE

Pseudoaneurysms remain a significant complication after vascular procedures. We hypothesized that TGF-β (transforming growth factor-β) signaling plays a mechanistic role in the development of pseudoaneurysms.

APPROACH AND RESULTS

Rat aortic pericardial patch angioplasty was associated with a high incidence (88%) of pseudoaneurysms at 30 days, with increased smad2 phosphorylation in small pseudoaneurysms but not in large pseudoaneurysms; TGF-β1 receptors were increased in small pseudoaneurysms and preserved in large pseudoaneurysms. Delivery of TGF-β1 via nanoparticles covalently bonded to the patch stimulated smad2 phosphorylation both in vitro and in vivo and significantly decreased pseudoaneurysm formation (6.7%). Inhibition of TGF-β1 signaling with SB431542 decreased smad2 phosphorylation both in vitro and in vivo and significantly induced pseudoaneurysm formation by day 7 (66.7%).

CONCLUSIONS

Normal healing after aortic patch angioplasty is associated with increased TGF-β1 signaling, and recruitment of smad2 signaling may limit pseudoaneurysm formation; loss of TGF-β1 signaling is associated with the formation of large pseudoaneurysms. Enhancement of TGF-β1 signaling may be a potential mechanism to limit pseudoaneurysm formation after vascular intervention.

Carotid artery reconstruction with a synthetic graft for aortitis syndrome

We performed a carotid artery reconstruction with a double velour knitted Dacron graft in a 33-year-old Japanese woman with a left common carotid artery aneurysm caused by the aortitis syndrome. After inflammatory signs resolved on steroid administration, a carotid artery reconstruction was performed. One month after the operation, the internal carotid artery was narrowed at the distal anastomosis site and 10 months later the same site showed aneurysmal dilatation. We conclude that it is important to control inflammation for a prolonged period and perform angiography regularly after such an operation.

[Anastomotic false aneurysms after under-diaphragmatic bypasses: about 25 cases]

The purpose of our study is to determine the causes and the management of anastomotic aneurysms. We report the cases of 25 patients with a mean age of 64 years at the time of initial surgical revascularisation. The mean interval between the first operation and the occurrence of anastomotic aneurysm is 5 years (range 2 months-11 years). The treatment consists on the interposition of a graft in 8 patients, anastomotic angioplasty in 9 patients and the reconstruction of the anastomosis in 8 patients. Hospital mortality was 20%. Late death occurs 3 patients and the long-term morbidity was evaluated at 22%. A recurrence of anastomotic false aneurysm occurred in 4 patients (16%) (Range 7 months-1 year). In conclusion anastomotic false aneurysm is one of the major complications of vascular reconstruction; careful follow-up can detect the rare instances of anastomotic aneurysm and reoperation can be accomplished with a low-rate of adverse outcome.

Pseudoaneurysm formation after infected modified Blalock-Taussig shunt: echocardiographic findings

The modified Blalock-Taussig (B-T) shunt is well recognized as a palliative procedure for cyanotic congenital heart disease in infants. Pseudoaneurysm formation after a modified B-T shunt is a rare complication. We present the case of a 9-month-old girl with tetralogy of Fallot who had undergone a modified left B-T shunt at 5 months of age and developed a pseudoaneurysm after an episode of infective endocarditis as detected by echocardiography. Compression of the left bronchus, displacement of the mediastinum to right chest, and paralysis of the left hemidiaphragm were found. Magnetic resonance images, computed tomography scans, aortograms, and selective angiograms demonstrated the presence of a large pseudoaneurysm. The compression syndrome gradually disappeared after aneurysmectomy.

Anastomotic femoral aneurysms: increase in interval between primary operation and aneurysm formation

OBJECTIVE

Anastomotic pseudoaneurysms continue to be a late complication of vascular surgery, particularly following prosthetic graft procedures. The purpose of this study was to investigate if a previously reported increase in interval between the original operation and the development of pseudoaneurysm was still valid.

DESIGN

Retrospective study.

MATERIAL AND METHODS

We reviewed the records of 76 patients who presented with 90 femoral aneurysms. The median age was 69 years (range: 39-83). The commonest previous vascular surgery was a aortofemoral bypass in 61 cases.

RESULTS

The interval between the original operation and the repair of the pseudoaneurysms was 9 years (range 1 month to 26 years).

CONCLUSIONS

This study confirms the previously noted trend of an increasing time to aneurysm formation from 3 years before 1975, 5 years between 1976 and 1980, and 6 years between 1981 and 1990.

Longitudinal forces acting at side-to-end and end-to-side anastomoses when a knitted polyester arterial prosthesis is implanted in the dog

In a previous study, which investigated the tensions at the proximal and distal end-to-end anastomoses of a vascular prosthesis, no significant differences were found in the longitudinal forces between the two anastomotic sites after different periods of implantation. The present follow-up study was devised to study the longitudinal forces at a proximal side-to-end and a distal end-to-side anastomosis using a warp knitted polyester prosthesis implanted as a canine thorocoabdominal bypass. The external surface of the prosthesis contained a specially printed "tension indicator" design, which enabled changes in length to be assessed photographically at the two anastomoses at the time of implantation and at sacrifice. The longitudinal force at each site was then calculated using a relationship obtained experimentally between the total longitudinal force and the changes in length of the virgin graft in vitro. The in vitro measurements on the prosthesis were performed using a computer-controlled laser calibration system. Although the results showed a tendency toward a gradual loss in longitudinal force at both anastomoses over 7 months in situ, statistical analysis showed no significant difference in the longitudinal force at the two anastomotic sites after any period of implantation. Histopathological and textile analysis also showed that the characteristics of the prostheses were similar at both anastomotic sites. This does not mean, however, that the intramural stress concentrations experienced by the two sites were the same. While comparing the level of the longitudinal forces measured in this study with those observed in the previous thoracic aorta study using end-to-end anastomoses, no significant differences were observed due to the different types of anastomoses. It would appear that the longitudinal force is not one of the main etiological factors that cause the formation and localization of anastomotic failure.

Anastomotic pseudoaneurysm of the ventricle after homograft placement in children

A pseudoaneurysm of the right ventricle was diagnosed postoperatively in 8 patients between 1986 and 1992. One pseudoaneurysm formed after placement of a Carpentier-Edwards conduit and the other seven arose after placement of a homograft between the right ventricle and the pulmonary artery. Both aortic (n = 3) and pulmonary (n = 4) homografts had been used. In 6 patients, the homografts had been augmented proximally with Dacron, Gore-Tex, or pericardium. Pseudoaneurysms originated between the augmentation patch and the homograft in 4 patients, between the homograft or conduit and the myocardium in 3 patients (1 patient with and 2 without an augmentation patch), and between the patch and the myocardium in 1 patient. The prior operations performed were placement of a palliative conduit for tetralogy of Fallot with pulmonary atresia (n = 5), repair of truncus arteriosus (n = 2), and repair of absent pulmonary valve syndrome (n = 1). Pseudoaneurysms were discovered from 5 weeks to 4 years after the operation. Symptoms were present in 3 patients; in the others, diagnosis was made during follow-up on the basis of routine imaging studies. Symptoms, when present, were due to compression of surrounding mediastinal structures. Pseudoaneurysms ranged in diameter from 1.0 to 5.0 cm. Echocardiography and color-flow mapping reliably identified the pseudoaneurysm in the 6 patients in whom it was performed. Characteristic features included a well-defined, narrow aneurysm neck leading to an extracardiac echo-free space. Color-flow mapping demonstrated to-and-fro flow through the neck of the aneurysm.(ABSTRACT TRUNCATED AT 250 WORDS)

Revision of the proximal aortic anastomosis after aortic bifurcation surgery

The implantation of an aortic bifurcation graft (ABG) for treatment of occlusive (OD) and aneurysmal (AD) aortoiliac disease is a standard technique with good long-term results and a relatively low incidence of complications. In a retrospective review of our patients from 1964 to 1993 only 36/1520 patients were identified who required reoperation at the proximal aortic anastomosis after ABG. Indications were graft occlusion (15/36) and graft stenoses (2/36), refractory to graft thrombectomy, proximal aortic anastomotic aneurysms (11/36) or graft infection (8/36). Graft occlusion or stenosis most frequently led to aortic reoperation in the OD-group (53.5%), recurrent aneurysmal disease (37.5%) and graft infection (37.5%) were the dominant indications in the AD-group. Mean time interval to reoperation was shorter in cases of graft infection (35 +/- 33 months) as compared with graft stenosis (66 +/- 58 months), graft occlusion (86 +/- 49 months) or aortic anastomotic aneurysms (152 +/- 90 months). Of the reoperations, 92% were done electively, 8% as emergency procedures. The perioperative course was uneventful in 67% of patients. Overall mortality rate after elective revisional surgery was 3% but reached 66% in emergencies. Postoperative morbidity and mortality was related to preoperative morbidity and the urgency of surgery, not with the mode of aortic intervention nor indication.

Late complications after aortic surgery

The incidence of false aneurysms, anastomotic stenoses, and ureteric obstruction is reported to be low in patients who have undergone aortic surgery. The use of intravenous peripheral digital subtraction angiography (IVDSA) with completion excretory urography (CEU) may provide a more sensitive means of long-term detection of these complications. The aim of this study was to (1) establish the incidence of anastomotic aneurysms, anastomotic stenoses, and ureteric obstruction after aortic surgery; (2) identify local and systemic factors that predispose to these complications; and (3) evaluate IVDSA as a single radiologic investigation to diagnose these complications. Forty-four patients who had undergone aortic surgery 1 to 12.3 years previously agreed to undergo IVDSA and CEU. False aneurysms were found at 10 distal anastomoses (none at the aorta), for an anastomotic incidence of 11.2% and a patient incidence of 15.9%. Endarterectomy and the femoral artery as a site of distal anastomosis were important factors in the development of anastomotic aneurysms, as were detected radiologically at eight aortic anastomosis (18%). There were no distal anastomotic stenoses. Hypercholesterolemia was more common in this group (62.5%) than in the overall group (21.2%). Three asymptomatic ureteric obstructions were diagnosed in two patients, both of whom had emergency surgery for ruptured aortic aneurysms. The higher incidence of anastomotic aneurysms, anastomotic stenoses, and asymptomatic ureteric obstruction sound merits careful follow-up. IVDSA with CEU may be a simple and effective method of detection.

Aortic false aneurysms after prosthetic reconstruction of the infrarenal aorta

False aneurysm of the infrarenal aorta was found at the site of proximal anastomosis in 13 patients after vascular reconstruction for lower limb arterial disease. The grafts involved were aortoprosthetic in one patient, aortobiiliac in two patients, and aortobifemoral in 10 patients. They had been implanted eight years prior to reoperation on the average (range six months to 15 years). False aneurysm was diagnosed because of abdominal pain in four cases, embolism in two cases, intestinal hemorrhage in one case, and during routine sonographic or computed tomographic (CT) scan surveillance in the six other cases. Femoral false aneurysm was associated in eight of 10 cases with femoral anastomoses. Aortic false aneurysms were repaired by interposition of a prosthetic tube between the infrarenal aorta and the original prosthetic graft in 11 cases and by changing the aortobifemoral graft in two cases. In one further case, repair was accomplished by implanting an aortobifemoral prosthetic graft laterally on a prosthetic tube interposed between the infrarenal aorta and the body of the original prosthetic graft, which continued to irrigate the internal iliac arteries. There was no mortality. Thrombosis of a prosthetic branch occurred in one case and was treated by thrombectomy. One patient underwent reoperation for intestinal obstruction. Two others had distal embolism responsible for toe necrosis. Anastomotic false aneurysms should be looked for routinely during the surveillance of prosthetic grafts implanted on the infrarenal aorta, especially when femoral false aneurysm is found. Preservation of pelvic vascularization must be an integral part of management.

The late complications of aorto-ilio-femoral Dacron prostheses: dilatation and anastomotic aneurysm formation

Dilated prosthetic grafts and anastomotic aneurysms are recognised as a long-term complication of aorto-ilio-femoral reconstruction. In the literature an incidence of 1-24% for anastomotic aneurysms and a mean dilatation of 85.7% for Dacron aortic prostheses is reported. In our own clinic the frequency of these complications was not known, and we started a follow-up study in order to establish: the mean dilatation of the prosthetic grafts, the actual incidence of anastomotic aneurysms and the relationship between these two. All patients (n = 61) who underwent aorto-ilio-femoral reconstruction between 1980 and 1985 were retrospectively studied. During the mean 8 years follow-up period 16 patients died (26%). Complete data were available from 36 patients, who underwent physical examination and ultrasonography. In the whole series the degree of dilatation varied from 0 to 44% with an average of 5.9% at the aortic level and 8.9% at the distal level. The diameters of 25 grafts remained unchanged, and the maximum dilatation observed was 44%. The incidence of anastomotic aneurysms in these patients was 13.8%. The anastomotic aneurysms were located at the following anatomical sites: aortic anastomoses 5.9%, iliac anastomoses 0 and 30.4% for the femoral anastomoses. There was no relationship between the dilated grafts and anastomotic aneurysms. In our clinic the degree of dilatation and the incidence of anastomotic aneurysms seems to be low, especially if we compare these results with the results reported by other investigators. None of the patients who underwent aorto-ilio-femoral reconstruction between 1980 and 1985 died or had to undergo emergency surgery because of graft failure or a ruptured anastomotic aneurysm.

False aneurysms after prosthetic reconstructions for aortoiliac obstructive disease

Several aspects of false aneurysm development after prosthetic resconstruction for aortoiliac obstructive disease were studied. For this purpose the long-term results (up to 20 years of follow-up) of 518 patients with implanted arterial prostheses in the aortoiliofemoral tract were retrospectively evaluated. Completeness of follow-up data was 83.2% 15 years after operation. A total of 101 false aneurysms (21 aortic, 53 iliac, and 27 femoral) were detected in 69 patients and verified by operation. The incidence per patient was 69 of 518 patients (13.3%). The incidences per anastomosis were: aortic, 21 of 438 anastomoses (4.8%); iliac, 53 of 835 anastomoses (6.3%); and femoral, 27 of 198 anastomoses (13.6%). Almost one half (47.5%) of all the false aneurysms were asymptomatic and were detected by angiography or ultrasonography. Chances for late survivors to develop a false aneurysm during follow-up were calculated by the life-table method. The chance to be free of a false aneurysm at any site was 77.2% 15 years after operation. These chances were 92.3%, 84.5%, and 76.2% for aortic, iliac, and femoral anastomoses, respectively. Analyses of subgroups showed that the development of a false aneurysm was significantly correlated with the presence of hypertension, multilevel disease, the type of suture material, and the type of anastomosis. These results indicate unexpectedly high chances for the development of false aneurysms in long-term survivors after aortoiliac or aortofemoral prosthetic reconstructions. We advocate the use of a life-long follow-up schedule with periodic angiography and ultrasonography for these patients.

Anastomotic aneurysms of the femoral artery: aetiology and treatment

The aetiology and treatment of 35 femoral false anastomotic aneurysms in 29 patients presenting over the 4-year period 1984-88 were reviewed retrospectively. The mean interval between primary anastomosis and false aneurysm repair was 6 years (range from 2 weeks to 16 years). Twenty-two (63 per cent) false aneurysms had occurred after previous aortobifemoral bypass grafting for occlusive aortoiliac disease. Seven (20 per cent) presented as acute surgical emergencies. Review of the records of the initial operations revealed that superficial wound infections with positive bacteriological cultures had been present in eight cases (23 per cent) and a further two (6 per cent) had lymph fistulae. Thirty-two false aneurysms were repaired, by simple reanastomosis in 14 cases, interposition grafting in 17 cases and in one case by complete revision to an aortobifemoral bypass graft. The risk of a further operative repair was less (P less than 0.05) following interposition grafting, than after simple revision. False aneurysm repairs, when compared with primary reconstructions done during the same period, were associated with more superficial wound infections (37 versus 10 per cent) and more explorations for haemorrhage within 30 days (19 versus 7 per cent).

Anastomotic aneurysms--an underdiagnosed complication after aorto-iliac reconstructions

Anastomotic aneurysms (AA) are recognised as a long-term complication of aorto-iliac (AI) reconstructions and in the literature an incidence of 2-8% is reported. From our own experience we suspected a much higher frequency of this complication and started a follow-up study in order to establish: 1. The actual incidence of AA and 2. The value of various methods of investigation in the diagnosis of this condition. During a 4-year-period (1977-1980) 303 patients (PTS) underwent an AI reconstruction and were the subject of this study. During the mean 8-year (range 6-10 years) follow-up period 158 patients died (52%). The 145 survivors underwent physical examination (PE), ultrasonography (US), and intravenous digital subtraction angiography (i.v. DSA). Complete data were available from 122 patients. The incidence of AA in the 303 patients of the original group, established by routine follow-up examination was 16/303 (5.1%). However, the incidence of AA in the 122 patients in this study was 36/122 (29.5%). These 36 patients developed 52 AA which were located at the following anatomic sites: aortic anastomoses 3/115 (2.6%), iliac artery anastomoses 18/146 (12.3%), femoral artery anastomoses 31/70 (44.3%). Fourteen of the 52 AA (33%) were operated on and the diagnosis was confirmed. The patient characteristics (age distribution, type of arterial reconstruction, indication for operation) of the group of 122 patients were not significantly different from the original group of 303 patients. Intravenous DSA proved to be the most reliable diagnostic test. Physical examination was relatively inaccurate when compared with imaging tests with a 37% false positive and 67% false negative rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Some mechanical properties of polypropylene sutures: relationship to the use of polypropylene in vascular surgery

This study was performed to examine some mechanical properties of Polypropylene sutures. Fifty segments of 3-0, 4-0, 5-0, 6-0, and 7-0 sutures were mounted in clamps and were subjected to stepwise elongation. Results showed that suture stiffness (elastic modulus) and breaking stress (tensile strength) correlated directly and linearly with the circumference or "skin" of the filaments and inversely with the cross-sectional area or "core" of the filaments. These data suggest that the strength of the suture may reside in the outer skin. These findings are related to the handling of Polypropylene in surgery, and to suture motion in grafts in patients.

Femoral false aneurysms: a recommendation for the method of repair

False aneurysm formation is a major complication of vascular surgery. The most frequent site of anastomotic false aneurysm formation is the femoral artery. Between January 1974 and June 1986, 26 patients with 42 femoral false aneurysms were treated at the Princess Alexandra Hospital. Aneurysms developed following Dacron arterial grafting (29 aneurysms), saphenous vein grafting (10 aneurysms), umbilical vein grafting (one aneurysm) and femoral embolectomy (two aneurysms). Arterial wall failure (with intact suture and graft) was the most frequent operative finding. Ten recurrent aneurysms developed. There was a significantly greater number of recurrences when resuture or patch repair was employed than when an interposition graft was used as a repair. The development of a femoral anastomotic false aneurysm should be viewed as a total failure of that anastomosis and repair should be by replacement with an interposition graft rather than repair of the failed anastomosis by suture or patch.

Anastomotic aneurysms--an unsolvable problem

Despite the advances in reconstructive vascular surgery anastomotic pseudoaneurysms have remained a serious problem. Even if a faultless operative technique is used this complication cannot always be averted. In order to avoid rupture or thromboembolism and to improve the patient's prognosis we suggest that all pseudoaneurysms are treated surgically except in poor risk patients. Between 1981 and 1986 119 anastomotic aneurysms in 68 patients were operated on in our department. 31.0% presented as infected aneurysms. 13.1% were recurrent after preceding aneurysm repair. The most common site was the femoral region following aortobifemoral bypass. Host vessel degeneration and acute inflammation of the anastomotic site seem to be the most important causative factors. Surgical repair usually consisted of resecting the anastomosis together with part of the host artery; in septic aneurysms limb salvage was attempted using extra-anatomic bypass. Postoperative mortality was 8.8%, minor complications occurred in 10.9%; 9 patients (13.1%) had to have an amputation.

Effect of force on anastomotic suture line disruption after carotid arteriotomy

Static and dynamic forces exerted on 6-0 polypropylene suture material after carotid arteriotomy were measured in 22 adult mongrel dogs. Force was measured in 11 normotensive animals (Group I) before and 6 weeks after carotid artery repair. Force was measured in the remaining animals during normotension and induced hypertension before and 6 weeks after operation. The tensile strength of each suture used in the study was measured by the manufacturer. The mean force required to break a 6-0 polypropylene suture measured 436.9 +/- 2 g, whereas knotting of the suture decreased the tensile strength to 316.9 +/- 3.9 g (p less than 0.001). The static and dynamic axial forces exerted on the suture after carotid arteriotomy in Group I was in the range of 26 g and decreased to 18 g at 6 weeks, whereas the 45 degree force exerted during the static dynamic phase measured in the range of 23 g and decreased to 16 g at 6 weeks (not statistically significant). The axial and 45 degree forces exerted on 6-0 polypropylene suture material in Group II under normotensive conditions were in the range of 14 g after carotid arteriotomy and ranged between 12 to 14 g at 6 weeks. Systolic hypertension did not result in a significant increase in axial or 45 degree forces during static or dynamic measurements, both in the range of 15 g after carotid arteriotomy. Measurements were similar at 6 weeks and ranged between 14 and 16 g. Our data indicate that 6-0 polypropylene suture material is an appropriate choice for repair of the carotid artery and that the suture material has sufficient inherent tensile strength to withstand forces generated in the neck region. Furthermore, our data indicate that spontaneous carotid artery suture line disruption is most likely related to damage to the suture strand during carotid artery repair rather than an inherent weakness in the suture material.

False aneurysm formation: a complication following the modified Blalock-Taussig shunt

False aneurysm formation is a rare complication of the modified Blalock-Taussig shunt. A patient is described in whom this complication arose 11 months after operation. Death resulted from rupture of the aneurysm into the right lung with associated massive hemoptysis. The onset of hemoptysis in patients with a functioning modified Blalock-Taussig shunt may be the first evidence of a developing false aneurysm.

False aneurysm of the ascending aorta from an expanded polytetrafluoroethylene (Gore-Tex) aortopulmonary shunt

A false aneurysm of the ascending aorta developed in a 25-month-old male infant with tetralogy of Fallot because of an expanded polytetrafluoroethylene (PTFE) shunt that had been inserted between the ascending aorta and right pulmonary artery when the patient was 3 months of age. Surgical repair of tetralogy of Fallot with ligation of the PTFE graft was performed at 19 months of age. The false aneurysm at the site of the systemic anastomosis to the shunt was discovered 6 months later and was successfully repaired. Because of the potential for graft dehiscence secondary to growth, we recommend that PTFE shunts be removed completely or, at least, ligated and divided at the time of corrective surgical intervention.

Fibroblast inhibition: a new and treatable cause of prosthetic graft failure

We have encountered two patients who had repeated false aneurysms, seromas, and unseated grafts which presented about 18 months after aortobifemoral grafting. An inhibitor of fibroblast growth was detected in each patient's serum by in vitro dilution tests. Normal ingrowth of fibrous tissue resumed after plasmapheresis, leaving the patients clinically stable for up to 3 1/2 years after treatment. Criteria for the diagnosis of fibroblast inhibition are an unseated prosthesis which simulates infection, no bacterial growth on carefully studied cultures, and inhibition of fibroblast growth by the patient's serum in vitro. The diagnosis should be entertained in the differential diagnosis of graft infection when an unseated graft is encountered in association with a late seroma or false aneurysm. Plasmapheresis removed the inhibitor. Fibroblast inhibition has not been reported previously.

Femoral anastomotic false aneurysms. An 11-year experience analyzed with a case control study

Eighty-three femoral anastomotic false aneurysms occurring in 51 patients were diagnosed from 1972 through 1982. Twenty-two (27%) presented with acute events. Seventy (84%) were confirmed by sonography and/or arteriography. Bilaterality (29%), recurrence (18%), and associated aortic false aneurysms (8%) were significant problems. Eight-one were repaired with a six per cent complication rate, including one death related to preoperative rupture. The 51 patients were evaluated for associated illnesses, risk factors, and etiologies of their false aneurysms. The most common single cause (61%) was host vessel degeneration with an intact suture line remaining attached to a disrupted Dacron limb. Twenty-three patients with host vessel degeneration were matched with case controls not developing false aneurysms. These two groups were matched for gender, age, and year of AFB and compared for associated illnesses and risk factors. Incidences of cigarette smoking, hypertension, cerebrovascular disease, coronary artery disease, diabetes mellitus, previous femoral endarterectomy, outflow disease, other aneurysmal disease, multiple groin operations, wound complications, and training levels of surgeons performing initial AFBs were similar for both groups. Factors observed significantly more often in patients who developed false aneurysms included serum lipid abnormalities (p less than 0.05), braided synthetic suture material as opposed to monofilament polypropylene (p less than 0.05), and continued abuse of tobacco following AFB (p less than 0.005).