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Biomedical subjects

J M Edwards

Publications and source records attributed to J M Edwards.

At least 55 records · Page 3Linked to original sources
PubMed1996

Results of bypass to the popliteal and tibial arteries with alternative sources of autogenous vein.

PURPOSE: The goal of an all-autogenous policy for infrainguinal arterial bypass requires that many bypasses be performed with alternative autogenous veins (AAV) because an adequate length of ipsilateral or contralateral greater saphenous vein (GSV) is not available. The durability and efficacy of infrainguinal vein bypasses constructed of venous conduits other than a single segment of greater saphenous vein (SSGSV) is, however, questioned. METHODS: AAV and GSV bypasses were reviewed from 1980 through 1994. Patients who required bypass to the popliteal or a tibial artery were compared for vascular surgical history and vascular disease risk factors and life-table survival. AAV and SSGSV procedures were compared for indications for surgery, morbidity and mortality rates, limb salvage rates in patients who underwent surgery for limb-salvage indications, subsequent need for revision, and life-table-assisted primary patency. RESULTS: Nine hundred nineteen autogenous vein bypasses were performed to the popliteal or a tibial artery--187 (20%) with AAVs, including whole or partial arm vein conduits in 144 grafts (77%). One hundred fourteen AAVs (61%) required vein splicing. The mortality rate was 2% for SSGSV bypasses and 1% for AAV bypasses. The morbidity rate was higher for GSV surgery as a result of increased wound complications (11% vs 5%; p=0.02). Sixty-seven percent of patients with AAV bypass extremities had undergone previous ipsilateral arterial surgery, compared with 20% of patients with SSGSV bypasses (p0.0005). AAV bypasses were more likely to be to a tibial artery (71% vs 45%; p<0.0001). Twelve percent of SSGSV and 15% of AAV popliteal bypasses required revision (p=NS). The 5-year assisted primary patencies were 82%, 77%, and 63%, with limb salvage rates of 91%, 86%, and 74% for ipsilateral SSGSV, contralateral SSGSV, and AAV femoropopliteal bypasses, respectively. Twelve percent of SSGSV and 30% of AAV tibial bypasses required revision (p=0.0001). The 5-year assisted primary patencies were 74%, 82%, and 72%, with limb salvage rates of 84%, 92% and 78% for ipsilateral SSGSV, contralateral SSGSV, and AAV femorotibial bypasses, respectively. CONCLUSION: AAV bypasses can provide overall results comparable with SSGSV bypasses.

Aged↗
PubMed1996

Current management of Raynaud's syndrome.

Raynaud's syndrome affects 20% to 25% of the population in cool, damp climates. Although its etiology and pathophysiology are poorly understood, treatment options do exist. For mild cases, the wearing of gloves, cold avoidance, tobacco cessation, and assurance that this is a nuisance condition that will not lead to finger amputation are often all that is required. Patients who fail this protocol are treated with extended-release nifedipine, 30 mg, at bedtime. In our experience, 70% to 80% respond with a decrease in severity and frequency of attacks, but 20% to 50% develop intolerable side effects. If nifedipine fails, we consider another calcium-channel blocker, an ACE inhibitor, or Dibenzyline. Biofeedback is offered to patients, but in our experience few are interested. Patients with digital ulceration are treated with nifedipine, pentoxifylline, and antibiotics as needed. We recommend soap-and-water washes and either a damp dressing or Silvadene cream. If there is chronic non-healing or intractable pain, we have on occasion performed a fingertip amputation. Although these do not tend to heal promptly, they generally do heal with time and provide excellent pain relief. We have not performed upper extremity sympathectomy for nonhealing finger ulcers in more than 20 years.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1995

Reducing perioperative myocardial infarction following vascular surgery. The potential role of beta-blockade.

OBJECTIVE: To determine which perioperative variables may influence the occurrence of perioperative myocardial infarction (PMI) following vascular surgery. DESIGN: Case-control study. SETTING: Combined Veterans Affairs Medical Center-university hospital vascular service. PATIENTS: During a 4-year period, all major vascular surgical operations (N = 2088) were evaluated with serial postoperative electrocardiography and cardiac enzyme measurements. Patients with PMI following nonemergent vascular surgery (N = 53) were matched with randomly selected control patients without PMI (N = 106) for age, gender, type of operation, hypertension, and symptoms of coronary artery disease. MAIN OUTCOME MEASURES: The two groups were compared for operative blood loss, blood pressure, and heart rate as well as length of operation, type of anesthetic, and use of perioperative beta-blockers, nitroglycerine, calcium channel blockers, vasopressors, and angiotensin-converting enzyme inhibitors. RESULTS: beta-Blockers were used less frequently in patients with PMI than in control patients without PMI (30% vs 50%; P = .01). Overall beta-blockade was associated with a 50% reduction in PMI (P = .03). Perioperative myocardial infarction was not associated with length of operation, type of anesthetic, blood pressure, or use of other medications. CONCLUSIONS: beta-Blockade is associated with a decreased incidence of PMI in patients undergoing vascular surgery. Prophylactic perioperative use of beta-blockers may decrease PMI in patients requiring major vascular surgery. A prospective randomized trial of beta-blockers in these patients appears to be warranted.

Adrenergic beta-Antagonists↗
PubMed1995

Upper extremity thromboembolism caused by occlusion of axillofemoral grafts.

BACKGROUND: The axillofemoral bypass graft (AxFG) is increasingly accepted as treatment for lower extremity ischemia caused by aortoiliac occlusive disease in high-risk patients. The incidence of upper extremity (UE) thromboembolism caused by occlusion of an AxFG and the results of treatment form the basis for this report. METHODS: From 1984 to the present, all patients undergoing axillofemoral bypass grafting were followed up in a vascular registry. A standardized operative technique, using an externally supported 8-mm polytetrafluoroethylene graft, was used in performing 202 AxFGs in 182 patients. UE thromboembolism caused by occlusion of an AxFG was identified by retrospective patient record review. RESULTS: Occlusion of an AxFG occurred in 20 patients. Fifteen patients (75%) underwent immediate revision of the occluded graft. Two patients (10%) developed UE thromboembolism simultaneous with graft occlusion. One of these patients had immediate revision of the graft, and 1 had brachial embolectomy only. This patient and 4 others (25%) had the occluded AxFG left in place. Four of these 5 patients (80%) developed UE thromboembolism at 26 days, 2 years, 5 years, and 7 years, respectively, after occlusion. Overall, six UE thromboembolic complications occurred in 5 patients. CONCLUSIONS: UE thromboembolism represents a significant and specific complication of occluded AxFGs in our series (2.7% of patients, 25% of occluded grafts). It may be prudent to prophylactically detach the axillary portion of the graft and repair the axillary artery in patients who do not require immediate revision of an occluded AxFG.

Algorithms↗
PubMed1995

Diagnosis and long-term clinical outcome in patients diagnosed with hand ischemia.

PURPOSE: The long-term clinical outcome of patients diagnosed with digital artery obstruction and symptomatic hand ischemia is largely unknown. Our long-term experience with the diagnosis of symptomatic digital artery obstruction and the long-term natural history of this condition forms the basis for this report. METHODS: From 1971 to 1985, 44 patients with symptomatic hand ischemia and palmar or digital arterial obstruction underwent arteriography and digital photoplethysmography (PPG). Patients were grouped according to severity of hand ischemia symptoms, including ulceration and digital amputation and the presence of a connective tissue disease (CTD). Arteriography was compared with PPG by creating an objective severity scale (digital obstruction index [DOI]). RESULTS: Average follow-up was 15.2 years (range 10 to 22 years). Initially 21 patients (48%) had moderate symptoms, and 23 patients (52%) had severe symptoms of hand ischemia. Follow-up symptoms in 28 patients improved (13 of 26 with CTD, 15 of 18 without CTD), in 15 patients (12 of 26 with CTD, 3 of 18 without CTD) remained unchanged, and in only 1 patient (1 of 26 with CTD) worsened. Seventeen (65%) patients with CTD (n = 26) had development of one or more ulcers, and six (24%) underwent one or more digital amputations. Four (22%) patients without CTD (n = 18) had finger ulceration (p < 0.012 compared with patients with CTD), and one patient (6%) underwent subsequent digital amputation (p = NS). The arteriography-DOI and PPG-DOI were equally accurate in determining severity of finger ischemia as manifested by severity of symptoms or ulcer development. CONCLUSIONS: The favorable long-term prognosis of symptomatic finger artery occlusion described herein mandates the avoidance of premature finger amputation. Patients with CTD fare worse, but even in this group tissue loss is modest. Finger PPG is as accurate as arteriography for determining severity of hand ischemia.

Adolescent↗
PubMed1995

Do normal early color-flow duplex surveillance examination results of infrainguinal vein grafts preclude the need for late graft revision?

PURPOSE: Optimal duration of postoperative duplex surveillance of infrainguinal vein grafts is not known. Previous reports have suggested nearly all vein graft stenoses are present within the first postoperative year, and normal duplex examination results during this time eliminate the need for ongoing graft surveillance. To determine whether surveillance may be safely discontinued in patients with normal early postoperative surveillance studies, we reviewed the color-flow surveillance examinations in our patients who underwent infrainguinal reverse vein graft revisions during a 4 1/2 year period. METHODS: Clinical and vascular laboratory records were reviewed of all patients who underwent infrainguinal reverse vein bypass grafting followed by subsequent graft revision for a duplex scanning-detected abnormality at our institution between January 1990 and July 1994. RESULTS: Of 447 infrainguinal reverse vein bypasses performed, 36 (8.1%) underwent surgical revision as a result of an abnormal finding during routine duplex surveillance. The initial postoperative duplex examination was obtained within 2 weeks of graft implantation in 23 (64%) patients, between 2 weeks and 3 months in 10 (28%) patients, and between 3 and 6 months in three (8%) patients. Duplex abnormalities prompting revision included 11 (31%) grafts with a mid-graft peak systolic velocity (PSV) < or = 45 cm/sec, 23 (64%) grafts with a focal PSV > or = 200 cm/sec, one graft with a PSV > or = 150 cm/sec but < 200 cm/sec, and one thought to be occluded by duplex but found to be patent by angiography. Abnormal duplex findings were initially detected within 2 weeks of graft implantation in five (14%) patients, between 2 weeks and 3 months in eight (22%) patients, from 3 to 6 months in 12 (33%) patients, from 6 to 12 months in six (17%) patients, and > 1 year in five (14%) patients. In only 25% of cases were mid-graft PSVs < or = 45 cm/sec or focal velocities > or = 200 cm/sec identified on the initial examination; 75% were found during subsequent surveillance. CONCLUSIONS: Although most reverse vein graft abnormalities detected by duplex surveillance and prompting graft revision appear within the first postoperative year, many are not detected on the initial examination. In our recent experience 31% of duplex abnormalities leading to vein graft revision were first detected more than 6 months after operation. Discontinuation of graft surveillance based on normal early findings will result in thrombosis of some vein grafts that may otherwise be salvaged.

Adult↗
PubMed1995

Deep vein thrombosis associated with lower extremity amputation.

PURPOSE: Patients undergoing lower extremity amputation are perceived to be at high risk for deep vein thrombosis (DVT). Limited data are available, however, to confirm this impression. The purpose of this study is to prospectively document the incidence of DVT complicating lower extremity amputation. METHODS: During a recent 28-month period, 72 patients (71 men, 1 woman; mean age 68 years) undergoing major lower extremity amputation (31 above-knee and 41 below-knee) were prospectively evaluated with perioperative duplex scanning for DVT. RESULTS: DVT was documented in nine (12.5%) patients (one bilateral, four ipsilateral, and four contralateral to amputation). Patients with a history of venous disease were at significantly higher risk for development of DVT (p = 0.02). Thrombi were located at or proximal to the popliteal vein in eight patients and were isolated to the tibial veins in one patient. DVT was identified before operation in six patients and after operation in three. Patients with DVT were treated with heparin anticoagulation, with no patient experiencing clinical symptoms compatible with pulmonary embolism. CONCLUSIONS: In our recent experience, lower extremity amputation is associated with DVT at or proximal to the popliteal vein in 11% of patients. Documentation of DVT prevalence is essential to assist surgeons in planning a management strategy for prevention, diagnosis, and treatment of DVT associated with lower extremity amputation.

Aged↗
PubMed1995

Screening for asymptomatic internal carotid artery stenosis: duplex criteria for discriminating 60% to 99% stenosis.

PURPOSE: The Asymptomatic Carotid Atherosclerosis Study (ACAS) showed that carotid endarterectomy reduces stroke risk in symptom-free patients with 60% or greater internal carotid artery (ICA) stenosis. This will surely lead to the performance of an increased number of screening duplex examinations. Assuming that positive study results will lead to arteriography or endarterectomy and keeping in mind the modest benefit for prophylactic endarterectomy demonstrated by ACAS (absolute risk reduction for ipsilateral stroke of 5.8% at 5 years), duplex criteria for 60% or greater ICA stenosis must have high positive predictive values (PPV). Determining criteria for 60% or greater stenosis, which emphasized high accuracy and PPV, forms the basis for this study. METHODS: Stenoses detected by angiography in 352 ICAs were blindly compared with those detected by duplex scanning. Duplex criteria were determined for highest overall accuracy in detection of 60% or greater ICA stenosis and for 95% or greater PPV. RESULTS: Maximal accuracy for detection of 60% or greater stenosis was 90%. This was achieved by the combination of a peak systolic velocity of 260 cm/sec or greater and an end diastolic velocity of 70 cm/sec or greater (sensitivity 84%, specificity 94%, PPV 92%). The 95% PPV for 60% or greater stenosis results from combining peak systolic velocity of 290 cm/sec or greater and end diastolic velocity of 80 cm/sec or greater. CONCLUSIONS: With use of these criteria duplex scanning accurately detects with high PPVs the threshold level of ICA stenosis defined in ACAS as receiving stroke reduction benefit from prophylactic carotid endarterectomy. These criteria should be useful for carotid artery screening and minimizing unneeded intervention.

Blood Flow Velocity↗
PubMed1994

Axillofemoral grafting with externally supported polytetrafluoroethylene.

OBJECTIVE: To evaluate the results of axillofemoral bypass grafting using externally supported polytetrafluoroethylene. DESIGN: Consecutive patients who were operated on by us from 1983 to the present were prospectively followed up in a vascular registry. The results of surgery with respect to morbidity and mortality, patency, limb salvage, and patient survival were determined by life-table methods. PATIENTS: A standardized operative technique was used to perform 184 axillofemoral bypass procedures in 164 consecutive patients (age range, 14 to 90 years; mean age, 67 years; female, 33%). Follow-up ranged from 0 to 95 months (mean, 23 months). RESULTS: Ischemia was the indication for 83% of the procedures, and aortic sepsis was the indication for 16%. There were nine operative deaths (5%) and 17 major complications. Life-table primary patency, limb salvage, and survival rates at 5 years were 71%, 92%, and 52%, respectively. Indication for surgery, patency of the superficial femoral artery, and the performance of multilevel procedures did not significantly influence patency. CONCLUSIONS: The results of axillofemoral grafting using polytetrafluoroethylene are equivalent to those achieved with other accepted methods of treatment for lower extremity ischemia, including balloon angioplasty, aortofemoral bypass, and infrainguinal bypass. Axillofemoral bypass is an appropriate technique that is deserving of more widespread use.

Adolescent↗
PubMed1994

Acute disruption of polytetrafluoroethylene grafts adjacent to axillary anastomoses: a complication of axillofemoral grafting.

PURPOSE: Acute disruption at or adjacent to axillary anastomoses of axillofemoral grafts has been sporadically reported. We have recently reported the patency and limb salvage results of a large number of axillofemoral grafts. In this report we describe a series of axillary artery-graft disruptions that occurred in these patients. METHODS: Beginning in 1983, axillofemoral bypass was performed by the authors using standardized operative technique and a single prosthetic graft material (8 mm externally supported polytetrafluoroethylene). Axillary anastomoses were placed on the first portion of the artery and were performed with the arm abducted and with the graft redundant. The records and operative reports of all patients with disruption were reviewed for findings and subsequent hospital course. RESULTS: Two hundred two axillofemoral grafts were performed from 1983 to 1993. Ten patients (5%) had axillary disruption at intervals ranging from 1 to 46 days (mean 21 days) after operation. Ischemia was the indication for operation for seven of the patients and infected aortic prostheses for three. Infection did not occur in any of the axillary wounds and was not the cause of any of the disruptions. Four disruptions occurred with arm abduction/shoulder elevation movements; three awakened patients from sleep, and one occurred while the patient was sitting quietly. For the other two patients, preceding activity was unknown. Brachial plexus deficit was present in one patient. Four of the 10 disrupted grafts were also acutely occluded. Operative findings included sutures pulling out of the artery in four cases, tearing or sutures pulling out of the graft in four cases, and cause unknown in two cases. Treatment included arterial ligation in one patient, and restoration of circulation through revision of the axillofemoral grafts in the other nine patients. There were no operative deaths. One patient had a prolonged hospital course followed by nursing home placement and died 9 months later. The brachial plexus deficit did not resolve. There have been no repeat disruptions. CONCLUSIONS: We conclude that axillofemoral grafting includes the potential for disruption of the proximal anastomosis, which has occurred in 5% of our patients. Although multiple steps have been recommended to avoid this complication, occasional cases continue to occur despite observing all precautions.

Acute Disease↗
PubMed1994

Surgical treatment of threatened reversed infrainguinal vein grafts.

PURPOSE: Current information concerning the results of surgical revision of threatened infrainguinal vein grafts is largely limited to in situ conduits. Infrainguinal grafts may be threatened by intrinsic graft lesions or significant stenosis in the adjacent inflow or outflow arteries. To assess the results of operative revision of infrainguinal reversed vein grafts, we reviewed our experience with surgical revision of threatened infrainguinal reversed vein grafts identified through a program of postoperative clinical and vascular laboratory graft surveillance. METHODS: All patients who underwent surgical revision of a threatened but patent infrainguinal reversed vein graft from January 1987 through April 1993 were identified through review of our vascular registry. Data were analyzed for type of vein used, date of original reversed vein graft, clinical and vascular laboratory findings leading to reversed vein graft revision, results of preoperative angiography, patient risk factors, operative techniques and complications, and long-term assisted primary graft patency and limb salvage. RESULTS: Ninety-six patients with 100 infrainguinal reversed vein grafts (69) femoral-popliteal, 31 femoral-tibial) underwent 117 surgical vein graft revisions or inflow procedures during the study period. Eighty-one percent of the original reversed vein grafts consisted of a single segment of greater saphenous vein. All revised grafts had at least a 50% stenosis in the graft itself or the proximal or distal artery. A single revision was performed in 85 grafts, two revisions in 13 grafts, and three revisions in two grafts. There were nine (8%) isolated inflow procedures, eight (7%) vein patch angioplasties, 62 (53%) interposition vein grafts, and 29 (25%) vein graft extensions to a new distal anastomotic site. The remaining nine (8%) procedures consisted of combinations of the above. Median time to primary graft revision after initial graft implantation was 15 months (range 2 days to 316 months). Mean time to secondary revision after primary revision was 21 months. Operative mortality was 0.9%. Cumulative assisted primary patency of the original grafts revised for stenotic lesions was 99%, 96%, and 92% at 1, 3, and 5 years, respectively. Limb salvage was 99%, 97%, and 97% at 1, 3, and 5 years, respectively. CONCLUSIONS: Although surgical revision of reversed vein graft requires much use of alternative vein sources, these procedures can be performed with minimum mortality and provide excellent assisted primary graft patency and limb salvage.

Adult↗
PubMed1994

Late survival after perioperative myocardial infarction complicating vascular surgery.

PURPOSE: Although early death from perioperative myocardial infarction (PMI) after vascular surgery is well established, long-term outcome in patients surviving PMI is unknown. This prospective study was designed to determine cardiac outcome and survival rates in patients with symptomatic and asymptomatic nonfatal PMI associated with peripheral vascular surgery. METHODS: During a 36-month period for 1989 to 1992, all patients undergoing vascular surgery at our institution were monitored for PMI with serial creatine kinase and myocardial band isoenzymes and electrocardiography. PMIs were classified as symptomatic (associated with chest pain, arrhythmia, congestive heart failure, or hypotension) or asymptomatic (electrocardiographic changes and/or elevated creatine kinase and myocardial band isoenzymes). Patients with PMI were then prospectively monitored and compared for late survival, with control patients undergoing vascular surgery without PMI during the same interval. RESULTS: During the study period 1561 major peripheral vascular procedures were performed. There were 47 PMIs (3.0%). Eleven (0.7%) PMIs were fatal, 31 were nonfatal, and five other patients with PMI died during operation of non-heart-related causes. Eight of 31 patients with nonfatal PMI had a "chemical PMI" with creatine kinase and myocardial band isoenzyme elevation as the sole indicator of PMI. During follow-up (mean 27.7 months), there was a higher incidence of both subsequent myocardial infarction and coronary artery revascularization among the patients with nonfatal PMI compared with control subjects (p < 0.05); however, survival for patients with nonfatal PMI at 1 and 4 years (80% and 51%) did not differ from that of control patients (90% and 60%) (p > 0.05). Patients with "chemical PMI" had similar patterns of subsequent myocardial infarction and coronary intervention as control patients. CONCLUSIONS: Patients surviving nonfatal PMI after peripheral vascular surgery have a higher incidence of subsequent adverse cardiac events and coronary artery revascularization than patients undergoing vascular surgery without PMI, but they have similar survival rates at 1 and 4 years. Patients in the enzyme-only PMI group have a similar outcome compared with control subjects suggesting that a perioperative "chemical MI" may not be a significant clinical event.

Aged↗
PubMed1994

Repeat leg bypass after multiple prior bypass failures.

PURPOSE: The optimal treatment of patients with severe lower extremity ischemia after multiple failed prior bypasses is unclear. It is presently unknown whether failure of attempted revascularization in these patients is so likely that such operation should not be elected. We have maintained an aggressive surgical policy of repeated revascularization regardless of prior failures. A review of our clinical experience with this difficult patient group was performed to determine the results of this policy. METHODS: From 1980 to 1992, 85 revascularization procedures were performed in 81 patients with lower extremity ischemia after failure of two or more prior infrainguinal bypasses in the same leg. All patients were prospectively entered and monitored in our vascular registry. Seventy-two operations were the third procedure, six operations were the fourth procedure, and seven operations were the fifth procedure on the same extremity. Twenty-six of the 85 procedures (30%) were revisions of failing grafts discovered by routine surveillance methods, whereas 59 were replacements of thrombosed grafts. Autogenous reconstruction was used in 67 procedures (79%), and prosthetic reconstruction was used in 18 procedures (21%). The distal anastomosis was to the popliteal artery in 19 patients and infrapopliteal artery in 66. RESULTS: Mean time to failure of the first leg bypass was 24 months and 4.9 months for the second bypass. Detailed hematologic screening revealed identifiable hypercoagulable disorders in nine (15%) of 59 patients screened after 1987. All nine had anticardiolipin antibodies. The operative mortality rate was 4%. Mean follow-up after the most recent operation was 17 months. The primary patency rate at 4 years was 79.8%. The limb salvage rate was 69.6% at 4 years. CONCLUSIONS: These results indicate that limb revascularization after two or more failed leg bypasses results in low operative mortality rates and surprisingly good primary patency and limb salvage rates at 4 years. The patient survival rate through 4 years is unexpectedly high. In our opinion these results justify an aggressive policy of limb vascularization after multiple failed prior bypasses.

Adult↗
PubMed1994

Spontaneous echo contrast and hemorheologic abnormalities in cerebrovascular disease.

BACKGROUND AND PURPOSE: Spontaneous echo contrast (SEC) is thought to represent a risk factor for cardioembolic stroke. In vitro studies suggest that SEC results from interaction between red cells and fibrinogen. To better understand the relation between SEC and stroke and to investigate the in vivo genesis of SEC, we examined the relation between SEC, the constituents of the blood, and plasma and serum viscosity in patients with acute stroke or chronic cerebrovascular disease. METHODS: Fifty patients with acute stroke or chronic cerebrovascular disease referred for transesophageal echocardiogram (TEE) were studied by transthoracic echocardiography and TEE. Complete blood count, fibrinogen, albumin, gamma-globulin, and plasma and serum viscosity determinations were made. Left atrial SEC was graded as absent, mild, or marked by means of TEE. RESULTS: SEC was absent in 31 patients, mild in 10 patients, and marked in 9 patients. Higher grade of SEC was associated with a significantly greater percentage of patients with atrial fibrillation and larger left atrial dimension. Atrial fibrillation was present in 23% of the patients in the SEC absent group, 50% of the patients in the mild SEC group, and 78% of the patients in the marked SEC group (P < .01). Left atrial diameter averaged 3.8 +/- 0.6 cm in the SEC absent group, 4.3 +/- 1.1 in the mild SEC group, and 4.9 +/- 0.7 in the marked SEC group (P < .001). Hematocrit, white blood cell count, and platelet count did not differ among the three groups. Fibrinogen, gamma-globulin, plasma viscosity, and serum viscosity values were all significantly higher in the presence of SEC (P < .05). Fibrinogen values were 361 +/- 97 mg/dL in the SEC absent group and 427 +/- 135 mg/dL in the marked SEC group. gamma-Globulin levels were 0.75 +/- 0.23 g/dL in the SEC absent group and 1.06 +/- 0.48 g/dL in the marked SEC group. Both plasma viscosity (1.97 cp) and serum viscosity (1.64 cp) were higher in the marked SEC group than in the SEC absent group (1.77 and 1.50 cp, respectively). CONCLUSIONS: In patients with acute stroke or chronic cerebrovascular disease, the severity of SEC was not related to albumin, hematocrit, white cell count, or platelet count but rather to elevated fibrinogen levels and concomitant increases in both plasma and serum viscosity. Moreover, increasing grade of SEC was associated with significantly increased left atrial diameter and a higher percentage of patients in atrial fibrillation.

Aged↗
PubMed1993

Anticoagulation followed by elective carotid surgery in patients with repetitive transient ischemic attacks and high-grade carotid stenosis.

OBJECTIVE: To evaluate the results of preoperative heparin therapy followed by carotid surgery for patients with repetitive transient ischemic attacks (TIAs) and high-grade carotid stenoses. DESIGN: A 4-year prospective study. SETTING: Oregon Health Science University Hospital and Portland (Ore) Veterans Affairs Hospital. PATIENTS: Twenty-nine consecutive patients with repetitive TIAs referable to 30 high-grade (> or = 70%) ipsilateral carotid stenoses were treated with short-term heparin anticoagulation, followed by cerebral angiography, routine preoperative evaluation, and subsequent carotid reconstruction. INTERVENTIONS: Heparin sodium anticoagulation was maintained for a mean of 5 days. Surgical management consisted of 24 standard endarterectomies, five bypasses to the internal carotid artery, and one external carotid endarterectomy. MAIN OUTCOME MEASURES: Primary outcome variables included perioperative hemorrhage, thrombocytopenia, stroke, and death. Secondary outcome variables included carotid occlusion and recurrent TIAs with heparin therapy. RESULTS: One symptomatic common carotid occlusion and one asymptomatic internal carotid occlusion occurred during preoperative heparin therapy. Thirteen patients had additional sporadic TIAs while receiving heparin. There were no preoperative cerebral infarcts, thrombocytopenia, or clinical bleeding associated with heparin therapy. There was one postoperative stroke and one death due to myocardial infarction. CONCLUSION: When necessary, heparin anticoagulation and delayed carotid reconstruction would appear to be an acceptable alternative to emergency carotid surgery in patients with high-grade carotid stenosis and acute repetitive TIAs.

Aged↗
PubMed1993

Human saphenous vein grafts explanted from the arterial circulation demonstrate altered smooth-muscle and endothelial responses.

PURPOSE: Animal models have been used to assess the function of vascular smooth muscle and endothelium of veins grafted into arterial circulation. The primary model consists of grafting the external jugular vein into the carotid artery of the rabbit. These studies suggest a selective increase in the responsiveness of the grafted veins to serotonin. However, in both human cardiac and peripheral vascular operations, the saphenous, not the jugular, is the vein most frequently used. Thus the propriety of the rabbit model is unknown. METHODS: Human saphenous veins and vein grafts were obtained from patients undergoing leg vein bypass graft revisions (n = 8). The reversed vein grafts were placed into arterial circulation for periods ranging from 4 to 26 months before removal (mean 16 months). All vessels were immediately cut into rings and suspended in organ chambers for recording isometric contractions to norepinephrine and serotonin. RESULTS: The maximal contractions elicited by both norepinephrine and serotonin were reduced in human vein grafts in comparison to the results in human saphenous vein (maximal response to norepinephrine 1.42 +/- 0.34 gm [vein graft] vs 4.59 +/- 1.13 gm [saphenous vein], p = 0.031; maximal response to serotonin 2.68 +/- 0.58 gm [vein graft] vs 4.72 +/- 1.11 gm [saphenous vein], p = 0.042). Human vein grafts were less responsive to norepinephrine than was saphenous vein (negative log of concentration that caused 50% of the maximal response -5.91 +/- 0.10 and -6.84 +/- 0.22, respectively; p < 0.009). After precontraction with norepinephrine (to 30% of the maximal response), saphenous vein, but not vein grafts, demonstrated endothelium-dependent relaxation to acetylcholine (maximum relaxation 27.4% +/- 6.8%; p = 0.001). CONCLUSIONS: Human saphenous veins grafted into arterial circulation exhibit loss of endothelium-dependent relaxation to acetylcholine and diminished contractions to agonists (norepinephrine and serotonin). In contrast to rabbit data, serotonin elicits dose-dependent contractions in both human saphenous vein and human vein grafts. Since the vascular wall contractility varies widely across species, the relevance of rabbit vein graft data to human bypass grafts is uncertain.

Acetylcholine↗