Biomedical subjects

E Ascher

Publications and source records attributed to E Ascher.

At least 37 records · Page 2Linked to original sources

PubMed2001

Differential proteolytic activity and induction of apoptosis in fibrous versus atheromatous plaques in carotid atherosclerotic disease.

PURPOSE: Atherosclerotic plaque instability may be a contributing factor to plaque complications, such as rupture, thrombosis, and embolization. Of the two types of plaques, atheromatous and fibrous, the atheromatous type has been reported to be vulnerable and unstable. This instability may be related to changes in the cell cycle and extracellular matrix degradation. Apoptosis may weaken the plaque structurally. In addition, alteration of the cellular component may lead to imbalances in associated proteolytic activity. Our study was designed to compare the two types of plaques in terms of apoptosis, apoptosis-inducing factors, namely Fas/CD95/APO-1 and CPP-32/YAMA/caspase-3, and proteolytic activity. METHODS: Carotid artery plaques were obtained from patients undergoing endarterectomy and were classified as either atheromatous or fibrous on the basis of established criteria. Histologic study included hematoxylin and eosin staining, Verhoeff's van Gieson elastin staining, and trichrome staining. Detection of apoptosis was performed with the TUNEL assay. Immunohistochemical studies were performed to localize the expression of CPP-32/YAMA and Fas/CD95. Gelatin gel zymography was used to compare proteolytic activity levels in the two types of plaque. RESULTS: Apoptosis was significantly higher (P <.001) in atheromatous plaques (4.90% +/- 1.27% [SEM]) as compared with fibrous plaques (0.86% +/- 0.46% [SEM]). Zymography demonstrated elevated levels of proteinases in atheromatous plaques. Immunohistochemistry revealed significant increases in the expression of Fas/CD95 (P <.04) and CPP-32/YAMA (P <.001) in atheromatous plaques as compared with that in fibrous plaques. CONCLUSIONS: This is the first study comparing molecular factors that render atheromatous plaques more susceptible to rupture than fibrous plaques. The higher number of apoptotic cells seen in atheromatous plaques as compared with fibrous plaques could contribute to their greater instability. Immunoreactivity to cytoplasmic death domain, Fas/CD95 and CPP-32/YAMA, a prominent mediator of apoptosis, was consistent with the numbers of apoptotic cells detected. The increased levels of proteolytic activity in atheromatous plaques may make these plaques more prone to rupture. These data identifying some of the molecular events and biochemical pathways associated with plaque vulnerability may help in the development of new strategies to prevent plaque rupture.

Aged↗

PubMed2001

Expression of molecular mediators of apoptosis and their role in the pathogenesis of lower-extremity varicose veins.

PURPOSE: In an earlier study, we observed a significant decrease in apoptosis in varicose veins, as compared with healthy veins, indicating that deregulated apoptosis plays a role in the pathogenesis of varicosities. In addition, significant differences were noted in the expression and subcellular localization of the cell cycle regulatory protein, cyclin D1 in varix tissues, as compared with controls. Because cell cycle checkpoint controls are linked to the signaling and execution of apoptotic cascades, we examined the expression of bcl-2 family members bax and bcl-x, known molecular mediators of apoptosis, and that of poly (ADP-ribose) polymerase (PARP), a downstream substrate of DNA cleavage. METHODS: Twenty varicose vein specimens were retrieved from 20 patients (10 men, 10 women; mean age, 53.6 +/- 4.7 years) undergoing lower-extremity varicose vein excision. Healthy greater saphenous vein segments (n = 27) were obtained from 27 patients (14 men, 13 women; mean age, 59.5 +/- 2.4 years) undergoing infrainguinal arterial bypass grafting surgery. All tissues were distal portions. As per CEAP classification for chronic lower-extremity venous disease, most of the patients were in class 2 for clinical signs (n = 11); some patients were in class 3 (n = 4) or class 4 (n = 4), and only one patient was in class 5. Five 5-microm thick sections from formalin-fixed, paraffin-embedded specimens were used as a means of immunohistochemically localizing the expression of bax, bcl-x, and PARP, and 10 random high-power fields per section were evaluated by two independent reviewers blinded to the clinical findings. Statistical analyses were conducted by means of chi(2), analysis of variance, Student and Fisher exact t tests with StatView software. RESULTS: Immunoreactivity to pro-apoptotic bax was significantly higher in the normal veins (P <.001). Cytoplasmic expression of bcl-x was prominent in the cells of the vasa vasorum in both varicose and healthy veins. PARP expression was diminished in the varicose vein group, with 2.8 +/- 0.7 (P =.01) and 1.4 +/- 0.5 (P =.05) cells per high-power field in the intima and media, respectively. Neither bax nor PARP was noted in the adventitia of varicose veins, although their expression was detected in this layer of the control group (P <.001). CONCLUSION: The entry of smooth muscle cells into the apoptotic pathway may be regulated by the induction of bax in this model, because there is significant presence of this pro-apoptotic protein in healthy veins. Both bax and PARP are downregulated in varicose veins, as compared with healthy veins, and this may play a significant role in the pathogenesis of varicose veins.

Apoptosis↗

PubMed2001

Impact of reintervention for failing upper-extremity arteriovenous autogenous access for hemodialysis.

PURPOSE: Although large published series have described their experience with the management of failed or failing prosthetic arteriovenous grafts for hemodialysis, there are scant data regarding failing arteriovenous fistulae (AVFs). To analyze the management of nonfunctioning or nonmaturing AVFs, we reviewed our experience with salvage procedures for these AVFs. MATERIALS AND METHODS: Of the 474 AVFs placed at our institution in 380 patients between June 1997 and March 2001, 75 revisions were performed in 46 patients (49 AVFs). Ages of these patients ranged from 29 to 94 years (mean, 68 +/- 1.4 years). Diabetic patients comprised 51%, and hypertensive patients comprised 75%. Twenty patients underwent 26 vein patch angioplasties, and 17 patients underwent 24 balloon angioplasties. Four patients required four vein interpositions, and 12 patients underwent 12 revisions of the fistula to a more proximal level. Extended salvage procedures consisted of four turn-downs to the basilic vein for proximal cephalic vein thrombosis or stenosis and five extension bypasses to the axillary or jugular vein for subclavian vein thrombosis. RESULTS: Follow-up ranged from 1 to 31 months (mean, 10 months). The patients who underwent open revisions tended to need fewer subsequent procedures. However, primary patency of the vein patch angioplasty was not significantly better as compared with balloon angioplasty (P = .8) by life table analysis. Patency after revision of a radial cephalic fistula and brachial cephalic fistula were not statistically different. One interposition failed during the follow-up, and one revision to a more proximal level thrombosed during the follow-up. Two of the turn-down procedures had thrombosed at 2 and 11 months. The remaining two turn-down procedures have remained functional at 1 and 24 months. One of the extensions thrombosed at 8 months whereas the other four have remained functional at 1, 6, and 8 months. CONCLUSIONS: Despite the limited follow-up data, this review suggests that simple and extended salvage procedures may allow maturation and add to the life span of AVFs for hemodialysis. In addition, these data suggest an advantage for open techniques as compared with percutaneous techniques but only in terms of requiring fewer subsequent procedures.

Adult↗

PubMed2001

Postoperative anticoagulation in vascular surgery: part 1. A retrospective comparison of clinical outcomes for unfractionated heparin versus low-molecular-weight heparin.

The use of postoperative anticoagulation is not uncommon for patients undergoing vascular procedures, whether for adjunctive therapy to the surgical procedure or for resumption of preoperative anticoagulation. Longer postoperative length of stay is necessary to achieve an adequate therapeutic international normalized ratio with traditional protocols that call for the use of unfractionated heparin. We retrospectively examined 195 cases to determine whether low-molecular-weight heparin, specifically enoxaparin, was an effective postoperative replacement for intravenous unfractionated heparin, with the impact on postoperative length of stay. There was no difference in the frequency of complications except for increased incidence of return to surgery for graft thrombosis (n = 11) in patients who received traditional intravenous unfractionated heparin with adjusted-dose warfarin daily (n = 139, P <.02). For all 195 vascular procedures combined, the average postoperative length of stay with use of enoxoparin was shortened with use of enoxaparin (P <.0008). There was a 2-day reduction in the average postoperative length of stay for the femoral-distal procedure group (n = 18, P <.004). In the first part of the article, we summarize our findings and offer new applications and ideas for vascular nurses to consider when postoperative anticoagulation is indicated after vascular procedures. Factors contributing to safe and efficacious postoperative anticoagulation with use of low-molecular-weight heparin, specifically enoxaparin, are presented to the vascular nurse. In the second part, we discuss the roles of members of the vascular team, as well as our experience with use of enoxaparin as implemented in the clinical setting.

Adult↗

PubMed2000

Programmed cell death (Apoptosis) and its role in the pathogenesis of lower extremity varicose veins.

The etiology of varicose veins remains elusive. We hypothesized that abnormal cell cycle events in the vein wall may contribute to changes in its structural integrity predisposing to varicosity development. Since cell cycle checkpoint controls are linked to the signaling and execution of apoptotic cascades, possibly apoptosis is a contributing factor in the pathophysiology of varicosities. The present study was designed to investigate whether programmed cell death varies in varicosities as compared to normal veins. Twenty-seven normal greater saphenous vein specimens were obtained from patients undergoing infrainguinal arterial bypass surgery, and 20 varicose vein specimens were retrieved from patients undergoing varicose vein excision. Apoptosis was detected by TUNEL assay. Expression of bcl-2 and cyclin D1 was noted by standard immunohistochemical techniques. Apoptotic cells were identified in 32 of the 47 specimens. Forty-eight percent of normal vein specimens displayed >3 apoptotic cells per 100 cells in the adventitia; 15% of the specimens of the varicose vein group showed such magnitude of apoptosis (p < 0.03). This increased apoptotic activity was not observed in media or intima of either vein group (p < 0.001). No significant difference in immunoreactivity to bcl-2 protein was observed in varicose vein specimens as compared to controls. Varicose vein specimens demonstrated increased nuclear expression of cyclin D1 whereas its cytoplasmic expression was significantly diminished (p </=0.02). These data show that programmed cell death is inhibited in varicose veins. Differential expression of cyclin D1 suggests that it may deregulate cell cycle events, thereby leading to varicosity formation.

Apoptosis↗

PubMed2000

Effect of p53 gene therapy combined with CTLA4Ig selective immunosuppression on prolonged neointima formation reduction in a rat model.

In a previous study, we have demonstrated a significant reduction of neointimal formation following adenovirus-mediated gene transfer of p53 to the injured rat carotid artery. The purpose of this study was to determine if the effect of p53 gene in reducing neointimal formation would still be present up to 8 weeks after arterial injury and whether it could be enhanced by adding immunosuppression. Cytotoxic T lymphocyte-associated antigen-4 Ig (CTLA41g), a novel immunosuppressive agent, is a recombinant soluble protein that blocks T cell-dependent immune response. Animals were divided into eight groups (n = 6 in each). In vivo gene transfer was used in isolated segments of balloon-injured rat carotid arteries. Genetically modified adenovirus encoding for wild-type p53 protein was applied at 8 x 10(10) pfu/mL. Control rats received adenovirus null at the same concentration. A daily dose of 300 microg of CTLA41g was given intraperitoneally, either once, twice, or three times. Expression of p53 was determined by Western blot analysis. Neointimal formation was assessed at 4 or 8 weeks by harvesting carotid arteries and determining the intima/media (I/M) ratio cross-sectional area measurements. p53 expression was confirmed by Western blot analysis. We concluded that adenovirus-mediated p53 gene transfer significantly decreases the formation of neointima up to 8 weeks following rat carotid injury. However, there is loss of effectiveness on neointimal formation inhibition as time elapses. When CTLA41g is added, there is significant improvement in results, with sustained neointimal formation inhibition at 8 weeks after the procedure.

Abatacept↗

PubMed2000

Upper extremity deep venous thrombosis: an underrecognized manifestation of a hypercoagulable state.

Although lower extremity deep venous thrombosis (LEDVT) has been associated with a hypercoagulable state, there are scant data available for patients presenting with upper extremity deep venous thrombosis (UEDVT). Therefore, we conducted a prospective study to determine whether such an association exists for UEDVT. Fifty-two patients who presented with UEDVT at our institution from August 1996 to June 1997 underwent a hematological profile consisting of activated protein C (APC) resistance, antithrombin III (ATIII) level and activity, factor V mutation (arginine 506 to glycine), protein C level and activity, protein S level and activity, factors II and X activity, lupus anticoagulant, and cardiolipin antibody. This represented 68% (52/76) of the total number of patients in whom the diagnosis of UEDVT was made by duplex ultrasonography during this time period. The ages ranged from 9 to 97 (mean 63 +/- 23 years). There were 22 males and 30 females. Twenty-five patients (48%) had a central venous line in place, 4 patients (8%) had a pacemaker, 14 patients (27%) had a history of neoplasm, and 7 patients (13%) had concomitant LEDVT. The results of our study showed that a hypercoagulable state may be an underappreciated contributing factor in the development of UEDVT. Contrary to prior belief that three sets of tests are needed to confirm the presence of a hypercoagulable state, these data also suggest that only two tests may be needed.

Adolescent↗

PubMed2000

Changes in the practice of angioaccess surgery: impact of dialysis outcome and quality initiative recommendations.

PURPOSE: Recommendations recently published by the National Kidney Foundation-Dialysis Outcome and Quality Initiative (DOQI) included an appeal for increased use of native arteriovenous fistulas (NAVFs) to improve overall patency and contain angioaccess costs. We evaluated the impact of the DOQI recommendations on angioaccess surgery and its outcome at our institution. METHODS: From June 1996 to April 1999, 483 angioaccess procedures were performed on 247 patients. There were 133 men and 114 women, with an average age ranging from 28 to 95 years (mean age, 69 +/- 0.59 years). Risk factors included smoking in 143 patients (58%), diabetes mellitus in 135 patients (55%), hypertension in 150 patients (61%), and coronary artery disease in 98 patients (40%). The patients were divided in two groups. Group I (pre-DOQI) included patients who had angioaccess procedures between June 1996 and November 1997, and group II (post-DOQI) included patients who had angioaccess procedures between December 1997 and April 1999. The types of procedures performed included placement of arteriovenous grafts (AVGs) in 122 patients (25%), creation of NAVFs in 99 patients (20%), revision of AVGs in 123 patients (25%), and temporary access procedures in 135 patients (28%). Forty-seven of the NAVF procedures were radial-cephalic fistulas (47%), 22 were brachial-cephalic fistulas (23%), and 30 were brachial-basilic fistulas (30%). Patients underwent serial ultrasonography scanning and physical examinations; the mean follow-up period was 9 months. Choice of angioaccess procedures and patency rates before and after implementation of the DOQI recommendations were compared. RESULTS: There was a significant increase in the use of NAVFs after implementing DOQI recommendations (5% vs 68%, P <.001). The 1-year primary patency rate of AVGs was less than that of arteriovenous fistulas (54% vs 85%, P <.001). During the study period, the percentage of AVGs placed at our institution that required revision (59%; 72 of 123) was higher than that of NAVFs that required revision (4%; 4 of 99; P <.001). There was no significant difference in the maturation rates of radial-cephalic fistulas (75%), brachial-cephalic fistulas (91%), and brachial-basilic fistulas (87%). CONCLUSION: By adopting the DOQI recommendations, we used NAVFs more often. This resulted in superior patency rates, compared with synthetic grafts. The liberal use of preoperative duplex venous mapping further increased NAVF use, surpassing the DOQI expectations for primary arteriovenous fistulas. Additionally, fewer revisions were required.

Adult↗

PubMed2000

Comparison between supra- and infrainguinal inflow sites for infrapopliteal PTFE bypasses with complementary arteriovenous fistula and vein interposition.

PURPOSE: the purpose of this retrospective study was to evaluate whether an inflow source proximal to the inguinal ligament had an adverse effect on infrapopliteal bypasses with complementary arteriovenous fistula/vein interposition (AVF/VI) when compared to similar bypasses originating from the common femoral artery (CFA). PATIENTS AND METHODS: over the last seven years, 112 infrapopliteal PTFE bypasses with AVF/VI were performed in 103 patients. There were 58 men and 45 women with ages ranging from 47 years to 88 years (mean 71 years). Indication for surgery was critical ischaemia in all. Seventy-seven (69%) of these were secondary operations and 35 cases (31%) were primary. A 6-mm ringed PTFE graft was used in all cases. A complementary distal AVF/VI was added in all cases. In 56 cases, the bypass originated from the common femoral artery (group I) and, in the remaining 56, it originated from the external or common iliac artery (group II). RESULTS: the overall perioperative mortality rate was 3%. The cumulative primary patency rates at 1, 2 and 3 years were 66%, 63% and 53% for group I and 72%, 66% and 59% for group II, respectively (NS). CONCLUSIONS: these data show that infrapopliteal PTFE bypasses with AVF/VI have similar patency rates when originating from arteries proximal to the inguinal ligament or from the CFA.

Aged↗

PubMed2000

Lower-extremity revascularisation without preoperative contrast arteriography in 185 cases: lessons learned with duplex ultrasound arterial mapping.

PURPOSE: we have previously reported our experience with lower-extremity duplex-ultrasound arterial mapping (DUAM) compared to contrast arteriography (CA) to predict lower-extremity bypass sites. The present study evaluates arterial revascularisation procedures for chronic limb ischaemia based on DUAM. MATERIALS AND METHODS: from January 1998 to July 1999, 195 patients (128 men, 67 women) underwent 211 lower-extremity revascularisation procedures based on DUAM. Indications for surgery were tissue loss, severe claudication, rest pain and popliteal aneurysm in 57%, 25%, 14% and 4% of the limbs, respectively. The mean age was 72+/-12 years and risk factors such as diabetes, hypertension, tobacco use, coronary artery and end-stage renal disease were present in 53%, 58%, 53%, 50% and 12% of the patients, respectively. Previous revascularisation procedures had been performed in 23% of the limbs. Preoperative evaluation consisted of DUAM alone (185) or of a combination of DUAM and CA (29 limbs). CA was deemed necessary due to a combination of technical difficulties that jeopardized adequate sonographic imaging and presence of disadvantaged run-off for medico-legal reasons. DUAM consisted of direct imaging of all major arteries from the distal aorta to the pedal circulation. Optimal inflow and outflow bypass anastomotic sites were selected according to a diagram based on DUAM. Adequacy of the inflow was additionally assessed by common-femoral-artery waveform and confirmed by intraoperative pressure measurements. Post-bypass CA was obtained to verify patency of the run-off. RESULTS: DUAM procedure time averaged 75+/-26 min. For patients who underwent only DUAM, the distal anastomosis was to the popliteal artery in 91 cases and to tibial or pedal arteries in 58 cases. Distal anastomosis was proximal to a significant lesion in two cases that required jump grafts. Cumulative patency rates at 1 and 3 months for popliteal bypasses were 96% and 90%, and for infrapopliteal bypasses 90% and 83%, respectively. Inflow procedures to the femoral artery, patch and balloon angioplasties accounted for the remaining 40 cases. Four primary amputations were performed after CA confirmed DUAM findings. CONCLUSIONS: contrary to general belief, these data show that high-quality arterial ultrasonography represents a safe alternative to preoperative CA, even for infrapopliteal bypasses. This non-invasive approach may be especially useful for patients with contrast allergy or impaired renal function.

Adult↗

PubMed2000

Lessons learned from a 6-year clinical experience with superior vena cava Greenfield filters.

PURPOSE: Therapy to prevent pulmonary embolism (PE) resulting from upper extremity deep venous thrombosis (UEDVT) remains controversial despite an increasing incidence of DVT of upper extremity origin. The purpose of this study was to evaluate the results of 72 superior vena cava Greenfield filters (SVC-GFs) placed in patients at risk for PE arising from UEDVT. METHODS: During the past 78 months, we placed SVC-GFs in 72 patients with UEDVT in whom anticoagulation was either deemed contraindicated (n = 67) or proved ineffective in preventing recurrent PE (n = 4) or extension of the thrombus (n = 1). There were 25 male (35%) and 47 (65%) female patients whose ages ranged from 25 to 99 years (mean, 74 years). Follow-up ranged from 10 days to 78 months (mean, 7.8 months). Sequential chest radiographs revealed no filter migration or displacement in 26 patients. RESULTS: Thirty-four patients died in the hospital of causes unrelated to the SVC filter or recurrent thromboembolism (mean time to death, 20 days). Follow-up of the surviving 38 patients ranged from 1 month to 78 months (mean, 22 months); none of these patients were seen with any evidence of PE. One SVC-GF was incorrectly discharged into the innominate vein and left in place. This vein remains patent 2 months after insertion without evidence of filter migration. CONCLUSIONS: We think that insertion of SVC-GFs is a safe, efficacious, and feasible therapy and may prevent recurrent thromboembolism in patients with UEDVT who are resistant to anticoagulation or have contraindications to anticoagulation.

Adult↗

PubMed1999

Values and limitations of duplex ultrasonography as the sole imaging method of preoperative evaluation for popliteal and infrapopliteal bypasses.

The purpose of this study was to evaluate whether duplex ultrasound arterial mapping (DAM) can reliably replace standard arteriography (SA) in the preoperative assessment of candidates for popliteal and infrapopliteal bypasses. This is the report of a two-phase study undertaken at our institution from July 1997 to May 1998. Carefully performed DAM averted the need for preoperative SA (51 of 58 procedures). The results of this study can be used as an impetus to initiate larger, multicenter protocols to further evaluate this newer noninvasive approach for patients presenting with severe lower-limb ischemia.

Aged↗

PubMed1999

Carotid screening with duplex ultrasound in elderly asymptomatic patients referred to a vascular surgeon: is it worthwhile?

The purpose of this study is to prospectively determine the outcome of carotid duplex ultrasound screening in patients referred to a vascular surgeon for problems other than carotid disease. During a recent 12-month period, 307 patients age 65 years and older (mean 76 +/- 8 years) were referred to one vascular surgeon for problems other than cerebrovascular disease. Fifty-one percent of the patients were male, 49% were female, 32% were diabetic, 32% were hypertensive, 31% smoked, 20% had coronary artery disease, and 64% had peripheral arterial occlusive disease. All patients underwent a screening duplex ultrasound exam of the carotid arteries as approved by our Institutional Review Board. The results of our study showed that the prevalence of asymptomatic carotid artery stenosis >70% among patients seen by a vascular surgeon for problems other than cerebrovascular disease is high (21%) and is associated with male gender, advanced age, diabetes mellitus and having quit smoking. Continued carotid artery duplex screening is warranted in this patient population greater than age 65 years.

Aged↗

PubMed1999

Ruptured versus elective abdominal aortic aneurysm repair: outcome and cost.

During a recent 30-month period, we repaired 10 ruptured abdominal aortic aneurysms (RAAA) at our institution. To evaluate the survival, postoperative morbidity, and financial impact of treating RAAA, we compared these patients with 10 randomly selected patients undergoing elective AAA (EAAA). Both groups were comparable for age, gender, and incidence of diabetes, hypertension, coronary artery disease, chronic obstructive pulmonary disease (COPD), and renal failure. Although we have noted a dramatic increase in survival for RAAA (90%), the morbidity continues to be unacceptably high (60%). Efforts should be made toward better detection of AAA prior to rupture as well as development of strategies to minimize or prevent these major complications. Potential average savings accrued from one patient undergoing EAAA repair rather than RAAA repair ($93,139. 21) can be used to perform screening abdominal ultrasound tests in patients at increased risk of having an AAA.

Aged↗

PubMed1999

The impact of an occluded internal carotid artery on the mortality and morbidity of patients undergoing coronary artery bypass grafting.

PURPOSE: To evaluate whether the presence of stenosis or an occluded internal carotid artery (ICA) influences perioperative stroke and mortality rates in patients subjected to coronary artery bypass grafting (CABG). MATERIAL AND METHODS: Between January 1995 and July 1998, 3,344 patients (59% males; 41% females) had CABG performed at our institution. Preoperative carotid duplex scans performed by registered vascular technologists at an ICAVL accredited laboratory were available for review in all patients. Of these, 3,101 (92.7%) had < 60% ICA stenosis (group A), 182 (5.4%) had 60% to 99% ICA stenosis (group B), and the remaining 61 (1.8%) had a occluded ICA (group C). In the latter group, 53 patients (87%) had < 60% contralateral ICA stenosis, while 8 (13.1%) had significant (60% to 99%) contralateral stenoses. Concomitant carotid endarterectomies (CEAs) were performed in 70 patients in group B (40%) and in 2 patients in group C (3.2%). Age, indications for surgery, prevalence of diabetes, hypertension, and smoking were similar in all groups. The mean pump time for groups A, B and C were 132, 138, and 125 minutes, respectively. The aortic cross-clamp time for group A, B, C were 78, 75, and 75 minutes, respectively. Statistical analyses were performed using the chi-square, Fisher's exact test, and unpaired t test. RESULTS: Perioperative stroke rates (30 days) were 1.6%, 3.8%, and 6.5% for groups A, B, and C, respectively. Group A results varied significantly from groups B (P < 0.03) and C (P < 0.003). No statistically significant difference was noted between groups B and C (P = 0.6). The presence of a contralateral ICA stenosis in group C patients was predictive of a perioperative stroke (25% versus 3.8%; P < 0.0001). Concomitant CEAs for contralateral severe ICA stenosis in group C were associated with higher stroke rate (100%) when compared with those in group B patients (4.2%; P < 0.02). Perioperative (30 days) mortality rates for groups A, B, and C were 3.6%, 6.6%, and 8.6%, respectively. The mortality rate for group A was lower than for groups B (P < 0.05) and C (P < 0.05). CONCLUSION: The presence of an ICA occlusion increases the morbidity and mortality in patients undergoing CABG. To the best of our knowledge, this is the first reported large series of patients that investigates the role of carotid occlusions.

Carotid Artery, Internal↗

PubMed1999

The use of duplex ultrasound arterial mapping as an alternative to conventional arteriography for primary and secondary infrapopliteal bypasses.

BACKGROUND: For more than 1 decade, duplex ultrasonography has been investigated as a potential replacement for invasive contrast arteriography (CA) prior to lower extremity revascularization. While some authors advocate the reliability of this methodology for infrainguinal imaging, revascularizations based on duplex ultrasonography alone are seldom reported. Our initial experience with duplex ultrasound arterial mapping (DUAM) for primary and secondary infrapopliteal bypasses performed without preoperative CA is reported in this series. METHODS: Twenty-eight infrapopliteal bypasses based on DUAM alone (26) and combined DUAM and CA (2) were performed. Indications for surgery were tissue loss in 22 cases and rest pain in 6. Eight patients (29%) had at least 1 previous ipsilateral revascularization. A schematic anatomical drawing based on DUAM helped the selection of optimal inflow and outflow bypass sites. Bypasses originated from the femoral arteries in 17 cases, external iliac in 3, and popliteal in 4, and from a previous graft in 4. The distal anastomosis was to the dorsalis pedis in 12 cases, posterior tibial in 7, anterior tibial in 6, and peroneal in 3. RESULTS: DUAM revealed unobstructed inflow in 24 cases, significant iliac stenosis in 1, and in 3 cases imaging was not possible owing to obesity. A pressure gradient of 15 mm Hg between donor and radial artery confirmed the stenosis diagnosed by DUAM, and was successfully treated with balloon angioplasty and stent placement. A single infrapopliteal runoff artery was identified by DUAM in 22 cases, 2 in 4 cases, and 3 in 2 cases. Preoperative CA was performed in 2 instances because of severe arterial calcification. Completion arteriography matched the run-off status predicted by DUAM in 25 out of 26 cases (96%). DUAM missed a significant anterior tibial artery stenosis that required a distal graft extension. One-, 3-, and 6-month patency rates were 96%, 85%, and 62%, respectively. Limb salvage rate was 86%. CONCLUSIONS: This early experience shows that DUAM may be a safe alternative to invasive conventional arteriography for the majority of patients (89%) presenting with critical ischemia and in need of infrapopliteal bypasses.

Adult↗

PubMed1999

p53 gene transfer to the injured rat carotid artery decreases neointimal formation.

PURPOSE: We studied the effect of adenovirus-mediated p53 gene transfer on the injured rat carotid artery to determine its ability to decrease the formation of neointima. METHODS: In vivo gene transfer was used in isolated segments of balloon-injured rat carotid arteries. Genetically modified adenovirus containing the gene encoding for wild-type p53 (AdWTp53) was applied in three concentrations: 8 x 10(10), 1.6 x 10(10), and 8 x 10(9) pfu/mL. Control rats received either adenovirus null (AdNull), 8 x 10(10) pfu/mL, or Medium-199 solution (vehicle). Expression of p53 was determined 4 days after gene transfer by Western blotting. Neointimal formation was assessed after 14 days by harvesting carotid arteries and determining the intima/media (I/M) ratio based on cross-sectional area measurement. Simultaneously, immunohistochemistry was done to detect the presence of p53 on smooth muscle cell nuclei. RESULTS: P53 expression was confirmed by Western blotting. There was a significant reduction in neointimal formation on all treated animals compared with controls. The highest dose of AdWTp53 (8 x 10(10) pfu/mL) resulted in a near-total arrest of neointimal formation (I/M = 0.09 +/- 0.03, mean +/- SEM) with P <. 0001 versus vehicle (I/M = 2.23 +/- 0.15) or AdNull (I/M = 2.12 +/-. 12). The intermediate dose of AdWTp53 (1.6 x 10(10) pfu/mL) resulted in an I/M value of 1.04 +/- 0.18, with P <.001 versus vehicle and P =.001 versus AdNull. The lowest dose (8 x 10(9) pfu/mL) resulted in an I/M value of 1.12 +/- 0.18, with P <.001 versus vehicle and P <. 002 versus AdNull. The immunohistochemistry was positive for the presence of p53 in rats infected with AdWTp53. CONCLUSIONS: Adenovirus-mediated gene transfer of p53 protein significantly decreases the formation of neointima in the rat carotid injury model. This may represent a potential therapy for restenosis in humans.

Adenoviridae↗

PubMed1999

The value and limitations of magnetic resonance angiography of the circle of Willis in patients undergoing carotid endarterectomy.

Magnetic resonance angiography is a useful technique to determine the patency of the circle of Willis when compared with conventional four-vessel angiography. The purpose of this study is to determine whether the integrity of the circle of Willis, assessed by magnetic resonance angiography, provides adequate collateral cerebral circulation during carotid endarterectomy and correlates with internal carotid artery back pressure. Over a recent 20-month period, 35 patients were studied preoperatively with magnetic resonance angiography of the carotid bifurcations of the circle of Willis and the vertebrobasilar system. All patients underwent standard carotid endarterectomy with intraoperative measurement of internal carotid artery back pressure. Patients with an internal carotid artery back pressure < 50 mmHg had an intraluminal shunt placed. Deficiencies in branches of the circle of Willis, the carotid bifurcation and the vertebrobasilar system determined by magnetic resonance angiography were correlated with internal carotid artery back pressure using Fisher's exact test. Only one patient had a completely intact circle of Willis. Eleven of 16 patients (69%) who had an internal carotid artery back pressure < 50 mmHg had an occluded A1 segment of the anterior cerebral artery combined with an occluded posterior communicating artery, whereas only five of 19 patients (26%) who had an internal carotid artery back pressure > 50 mmHg had similar findings (P < 0.03). Severity of occlusive disease of the contralateral internal carotid artery and the basilar artery did not independently predict internal carotid artery back pressure. An occluded anterior branch of the circle of Willis in combination with an occluded posterior branch of the circle of Willis is associated with an internal carotid artery back pressure < 50 mmHg. Although magnetic resonance angiography of the circle of Willis may provide valuable anatomic information, it is not sufficiently accurate to predict the need for carotid shunting and therefore its use cannot be justified on a routine basis.

Aged↗