Biomedical subjects
Publications and source records attributed to F A Weaver.
Successful management of the difficult peripheral vascular injury requires a multidisciplinary approach. Prompt recognition of the vascular injury and adherence to the recognized principles of vascular repair provide a successful short-term surgical result. The long-term consequences of an injury are determined by the associated orthopedic, soft tissue, and nerve injuries.
Surgical repair of an abdominal aortic aneurysm in conjunction with radical cystectomy and orthotopic urinary diversion can be safely performed without morbidity secondary to excessive blood loss, operative time, or vascular graft infection. The techniques required for this combined procedure and a case report are discussed.
PURPOSE: Early results of a prospective study that compared surgical revascularization and thrombolysis for lower extremity arterial and graft occlusions have been published. This report details the final results in patients who have native artery occlusions. METHODS: Two hundred thirty-seven patients who had lower extremity ischemia as a result of iliac-common femoral (IF; 69 patients) or superficial femoral-popliteal (FP; 168 patients) occlusion, and had symptomatically deteriorated within the past 6 months were randomized to catheter-directed thrombolysis (150 patients) or surgical revascularization (87 patients). After diagnostic arteriographic examination but before randomization, the optimal surgical procedure was determined. Lytic patients were randomized to recombinant tissue plasminogen activator (rt-PA; 84 patients) or urokinase (UK; 66 patients). Recurrent ischemia, morbidity, amputation, and death rates were determined at 30 days, 6 months, and 1 year, and were analyzed on an intent-to-treat basis. RESULTS: For patients randomized to lysis, a catheter was properly positioned and the lytic agent delivered in 78%. This provided a reduction in the predetermined surgical procedure in 58% of patients who had an FP occlusion and 51% of those who had an IF occlusion. rt-PA and UK were equally effective and safe, but lysis time was shorter with rt-PA (8 vs 24 hr; p < 0.05). At 1 year, the incidence of recurrent ischemia (64% vs 35%; p < 0.0001) and major amputation (10% vs 0%; p = 0.0024) was increased in patients who were randomized to lysis. Factors associated with a poor lytic outcome included FP occlusion, diabetes, and critical ischemia. No differences in mortality rates were observed at 1 year between the lysis and surgical groups. CONCLUSION: Surgical revascularization for lower extremity native artery occlusions is more effective and durable than thrombolysis. Thrombolysis used initially provides a reduction in the surgical procedure for a majority of patients; however, long-term outcome is inferior, particularly for patients who have an FP occlusion, diabetes, or critical ischemia.
PURPOSE: This study was undertaken to examine the relationship between intraoperative color-flow duplex (CFD) findings and the development of restenosis in patients undergoing carotid endarterectomy (CEA). METHODS: Seventy-eight patients (43 male and 35 female; mean age, 65 years) underwent 86 CEAs (eight staged bilateral) and intraoperative CFD during a 31-month period. Three patients (three CEAs, 3%) underwent both CFD and a completion arteriographic scan. Patients were observed in a postoperative protocol using CFD surveillance. The follow-up interval ranged from 6 to 24 months (average, 12 months). RESULTS: After undergoing CEA, 10 patients (10 CEAs, 11%) had an abnormality detected by intraoperative CFD; one was confirmed with a completion arteriographic scan. These abnormalities consisted of elevated peak systolic velocities (PSV) with a mosaic color pattern suggesting turbulence seen in six CEAs, including one internal carotid artery (ICA) with abnormal hemodynamics and an unremarkable completion arteriogram. Intimal defects on B-mode were seen in another four CEAs. These carotid arteries were reexplored, defects (intimal flaps with platelet thrombus) were confirmed by direct examination, and all were repaired with or without a patch (six ICAs, three external carotid arteries, and one common carotid artery). No cerebrovascular events occurred in the perioperative period. No carotid restenosis (> or = 50% diameter reduction) was identified during follow-up of 43 patients (48 CEAs, 56%). Two patients had recurrent neurologic symptoms. CONCLUSION: Intraoperative CFD is an effective test for detecting flow abnormalities or intimal defects in patients undergoing CEA. Ensuring normal intraoperative hemodynamics after CEA may be a major factor associated with decreased incidence of perioperative cerebrovascular events and subsequent carotid artery restenosis.
During and 8-year period, 51 patients with renovascular hypertension were evaluated. Etiologies of renovascular disease included atherosclerosis 29 (57%), Takayasu's arteritis 11(22%), fibromuscular dysplasia six (11%), renal artery dissection two (4%), trauma two(4%¿ and aneurysm one (2%). Fifteen (29%) patients had bilateral renal artery disease, and 16 (31%) had associated chronic renal failure. Seven patients initially underwent percutaneous transluminal angioplasty, three of whom later required operative intervention for recurrent hypertension, and one required repeat angioplasty. Three patients had no further intervention. Forty-seven patients underwent surgical revascularization tailored to the angiographic and intraoperative findings. Procedures performed included 36 (55%) aortorenal bypasses; 12 (18%) endarterectomies; five (8%) ex-vivo reconstructions; three (4%) renal artery reimplantations; two (3%) other visceral artery-to renal (hepatic/splenic) reconstructions; one (2%) renal artery patch graft; and seven (10%) nephrectomies. Concomitant aortic replacement occurred in 20 cases. There were two deaths, and remedial operations for recurrent hypertension were required in three patients. The mean follow up was 12 months (range 6-45 months). Hypertension was cured in 25 (57%), improved in 14(32%), and unchanged in five (11%). Of the 16 patients with chronic renal failure, eight (50%) had a reduction in serum creatinine >10%. The etiology of renovascular hypertension is variable. Although transluminal angioplasty may be indicated in selected patients, surgical revascularization is usually necessary. A flexible operative approach to accommodate the variable patterns of renal artery disease optimizes surgical results. Renal revascularization may provide and improvement in excretory renal function.
Although the renin-angiotensin system has been implicated in the pathogenesis of renovascular hypertension (RVH), blood pressure does not parallel serum levels of renin or angiotensin II (AII) in chronic RVH. Upregulation of angiotensin II type 1 receptor (AT1) gene expression may explain this paradox and clarify the pathogenesis of chronic hypertension in RVH. To investigate this hypothesis, we studied changes in AT1 mRNA levels in rat kidney in a two-kidney, one-clip (2K1C) rat model of RVH. Animals were sacrificed at 1 or 10 weeks postoperatively. Blood pressure was measured with a tail cuff photosensor. Relative gene expression was quantitated by dot blotting total RNA, hybridizing with a cDNA probe for AT1, and quantitating signal intensity with scanning densitometry. A significant increase in blood pressure (BP) was observed at 1 week postoperatively (delta BP: 2K1C = +24 mm Hg, n = 3; controls = +7 mm Hg, n = 3; P < 0.05), and at this time relative AT1 mRNA levels actually decreased in the clipped kidney (P < 0.05). Hypertension intensified 10 weeks postoperatively (delta BP: 2K1C = +46 mm Hg, n = 20; controls = -17 mm Hg, n = 7; P < 0.005) and, remarkably, was paralleled by an almost sevenfold upregulation of AT1 mRNA levels in the clipped kidney (P < 0.005) and more than eightfold in the unclipped kidney (P < 0.005) of 2K1C animals. Upregulation of renal AT1 gene expression could lead to increased AT1 receptor production, hypersensitivity to AII, and chronic hypertension in RVH.
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This report describes the surgical management of 24 patients with concurrent abdominal aortic aneurysm (AAA) and urinary tract neoplasm. The patient population consisted of 22 men and two women whose average age was 65.5 years. AAA sizes ranged from 3.1 to 9.0 cm (mean 5.2 cm) in diameter. Urinary tract neoplasms included transitional cell carcinoma (TCC) of the bladder (n = 19), adenocarcinoma of the prostate (n = 3), and TCC of the renal pelvis (n = 2). Urologic procedures included radical prostatectomy, radical nephroureterectomy, and radical cystoprostatectomy with continent or ileal loop urinary diversion. The AAA was resected at the time of the urologic procedure in 12 patients (group I) or prior to the urologic procedure in five patients (group II) and was left in situ in seven patients (group III: AAA diameter 3.1 to 5.5 cm). All patients but one in group I recovered without complications. One patient developed an infection postoperatively as a result of fluid collection anterior to the aortic vascular graft; the fluid was successfully drained and the patient subsequently recovered uneventfully. All patients in group II had a marked retroperitoneal desmoplastic reaction at the time of the urologic procedure as a result of prior aneurysmectomy, which complicated the ureteral dissection. One patient later required an ileal ureteral reconstruction for obliterative fibrosis of the ureter. At a mean follow-up of 34 months, no infectious or mechanical complications of the vascular prosthesis occurred in group I or II. Eight patients in group I and two in group II are alive. Three have died of metastatic disease and two of myocardial infarction. Of the seven patients in group III, four subsequently required AAA resection for an increase in AAA size and three have died.(ABSTRACT TRUNCATED AT 250 WORDS)
During a 62-month period, carbon dioxide was used to supplement or completely replace iodinated contrast agents in performing 27 transluminal angioplasties in 26 patients. The arterial segments addressed included the following: renal in two cases, iliac in five, femoral/popliteal in 15, infrapopliteal in two, and combined in three. Indications for intervention included lower extremity gangrene in 11 cases, ischemic ulceration in 10, rest pain in three, claudication in one, and ischemic nephropathy in two. Contraindications to iodinated contrast agents included renal insufficiency resulting from diabetes (n = 20) or ischemic nephropathy (n = 2) and congestive heart failure (n = 4). Eight procedures used carbon dioxide as the sole contrast agent, whereas 19 required supplementation of carbon dioxide with a mean of 39 ml of nonionic contrast medium. Technical success was achieved in 25 procedures with significant hemodynamic improvement in 20 patients. Complications included transient deterioration in renal function in two patients and myocardial infarctions in two. At 30 days 18 patients had demonstrated significant clinical improvement. Patients at high risk for iodinated contrast-related complications may undergo transluminal angioplasty using carbon dioxide/digital subtraction arteriography to reduce or eliminate the need for iodinated contrast agents.
PURPOSE: The purpose of this study was to compare the accuracy of a limited B-mode compression technique (BMCT) with a complete color-flow duplex venous examination (CDVE) for the detection of proximal deep vein thrombosis (DVT). METHODS: We prospectively studied 72 patients (20 men and 52 women) for DVT. Two technologists blinded to each other performed either BMCT or CDVE independently. The BMCT is an abbreviated technique compressing two sites per limb. One site was the saphenofemoral junction including the superficial femoral and deep femoral vein confluence; the other was the saphenopopliteal junction including tibial vein confluence. Total limbs studied were 144. CDVE was considered the gold standard for purposes of sensitivity, specificity, and accuracy. RESULTS: The technical failure rate of BMCT was three of 144. In all technically satisfactory examinations, the BMCT result was positive in 15 of 14 limbs, and the CDVE result was positive in 13. Sensitivity of BMCT was 100%, specificity was 98%, and overall accuracy was 99%. There were two false-positive results with BMCT; both were cases of popliteal veins deep to the artery leading to difficulty in compression. The BMCT was able to detect chronic thrombus, floating thrombus, and small thrombus behind femoral vein valve cusps. CONCLUSION: These data suggest that BMCT is a rapid, acceptable, alternative technique for detecting proximal DVT. In cases of equivocal or positive findings, the spectral and color-flow Doppler examination should be used to confirm the results.
Blunt innominate chest trauma is relatively rare, with only 70 cases being reported in the surgical literature since 1960. This report describes a 20-year-old male who sustained a blunt chest injury that resulted in an innominate artery dissection. The patient's clinical course and management are discussed, as well as a review of the surgical literature.
Between 1989 and 1993, 97 patients with stages B3 and/or C nonseminomatous germ cell tumors of the testes underwent induction chemotherapy followed by retroperitoneal lymph node dissection. Of these patients 6 (ages 22 to 41 years) had gross extension of tumor into the aortic adventitia at operation, which necessitated en bloc aortic and, on 3 occasions, iliac artery resection for complete tumor removal. Aortic continuity was restored by a woven Dacron tube or bifurcated graft. All grafts were covered with omentum. There were no postoperative vascular complications. Pathological study of the residual retroperitoneal disease demonstrated that 2 patients had mature teratoma only, 2 had mature teratoma with occasional nests of immature teratoma and 2 had residual yolk sac, embryonal or choriocarcinoma elements. The latter 2 patients underwent postoperative salvage chemotherapy with varying combinations of bleomycin, etoposide, ifosfamide and cisplatin. At 4 to 55 months 4 patients were disease-free, while 2 died of metastatic disease. No problems related to the aortic reconstruction have occurred. This small experience demonstrates that, if necessary, complete surgical en bloc extirpation of bulky metastatic germ cell tumors and the aorta/iliac artery can be performed safely with a satisfactory long-term outcome.
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During a 20-year period from 1973 to 1992, 109 patients underwent early operation for acute popliteal artery trauma. Clinical variables were analyzed for their association with amputation. Gunshot wounds accounted for the majority of injuries (73%), followed by shotgun wounds (18%), stab wounds (6%), iatrogenic injuries (2%), and lacerations (1%). Fasciotomies were performed selectively in 41% of patients. Seven patients (6%) lost the injured extremity despite arterial repair. The mean time from injury to arterial repair was not significantly different for patients with or without subsequent amputation (8.6 +/- 3.6 and 9.7 +/- 7.4 hours, respectively; p = 0.69). Delay in diagnosis longer than 6 or 12 hours after the injury did not increase the risk of amputation. Other factors not associated with limb loss were preoperative ischemic neurologic deficit or compartmental hypertension, concomitant fracture, and popliteal vein injury. Severe soft tissue injury (p < 0.0001) or postoperative wound sepsis (p < 0.0001) substantially increased the risk of amputation. Delayed fasciotomies were uncommon (4%) but were associated with a significantly increased risk of amputation (p < 0.0001). Vein grafting for arterial repair (p = 0.0017) and shotgun injuries (p < 0.0001) were associated with amputation to the extent that they were related to severe soft tissue injury. The degree of soft tissue trauma and subsequent infection of devitalized tissue limits the success of popliteal arterial repair. Changes in the mechanism of trauma, liberal use of four-compartment fasciotomies, and aggressive management of soft tissue injury resulted in a significant decline in the amputation rate from 21% (4/19) in the first 5 years to 0% (0/39) in the last 5 years of the study.
The most common cause of failure of hemodialysis access sites is stenosis within the site. The stenoses have traditionally been corrected surgically, but endovascular techniques may be an alternative method to treat these flow-limiting lesions and maintain graft patency. Over a recent 17-month period, endoluminal stents to relieve stenoses resistant to balloon dilatation alone were placed in 14 access sites. All sites were located on the upper extremity (13 PTFE bridge grafts and 1 A-V fistula). A total of 20 stents were placed: seven at the venous anastomosis, 12 in the venous outflow tract (including 3 in the subclavian vein), and one within the graft. Nine patients had placement of a single stent, four patients had two stents placed, and one patient had three. An additional eight stenotic lesions within these 14 sites were successfully dilated without need of a stent. After stent placement, these 14 sites have remained functional for a mean of 6.2 months. Four were functioning without further intervention at a mean of 8.5 months. Nine sites occluded at a mean of 4.7 months. The remaining site remained functional until death of the patient 10 months after stent placement. Of the nine failed sites, four developed restenosis at the site of stent placement, four developed stenoses at other sites, and the other site was abandoned. Three stents were placed in subclavian vein stenoses, and none of these has failed. Further study is necessary to determine whether endovascular stenting of dialysis access site stenoses will prove to be a durable, cost-effective alternative to surgical revision.
Ex vivo renal artery reconstruction is a technique used to repair renal vascular lesions not amenable to conventional in situ methods of revascularization, either because of anatomical considerations or the inability of the kidney to tolerate the extended period of warm ischemia necessary to complete the procedure. In general, this refers to lesions at or beyond the division of the main renal artery into the segmental branches. The kidney is mobilized to the level of the abdominal wall after dividing the origins of the renal artery and vein from the aorta and inferior vena cava, respectively. The ureter is left intact. The kidney is cooled by placing it in an external slush bath and by perfusion through the renal vessels of a cold electrolyte solution. A suitable conduit (usually saphenous vein or hypogastric artery) is then prepared for grafting. After completion of the distal anastomosis(es), the kidney is returned to the renal fossa, and the proximal anastomosis to the aorta is completed. The renal vein is then reattached, thus completing revascularization of the kidney. We report our experience with five orthotopic ex vivo renal artery reconstructions. Indications for the procedure, details of the technique, and expected results are discussed.
Intra-arterial thrombolytic therapy is an important advance in the treatment of arterial occlusive disease. Reports of results, morbidity, and mortality have been highly variable. This review was undertaken to assess the recent results of thrombolytic therapy with urokinase (UK) at our institution. From 1988-1992, 42 lower extremities in 41 patients with severe peripheral vascular disease underwent intra-arterial thrombolytic therapy. Sites of occlusion consisted of 6 iliac, 21 superficial femoral, 11 popliteal, and 20 infra-popliteal segments. Lytic therapy consisted of a regional infusion of UK with concomitant heparin anticoagulation. The most common UK loading dose was 250,000 units (60,000-750,000) followed by a continuous infusion of approximately 100,000 units/hour (60,000-240,000) for up to 72 hours. Technical success, defined as partial or total resolution of the arterial occlusions, occurred in 26 (62%) limbs. A concomitant endovascular procedure was required in 19 extremities following successful lysis. Immediate clinical success, defined as restitution of a distal pulse or increase in ABI > 0.10, occurred in 22 of 26 technically successful procedures. The four clinical failures and all 16 technical failures required either a major amputation or revascularization. There were 18 major complications in 18 patients (43%): seven thromboembolic, two arterial dissections, nine hemorrhagic. Seven hemorrhagic complications required transfusion of 1-6 units of blood, and two deaths occurred due to postprocedural hemorrhage, shock, and myocardial infarction. Hemorrhage was not related either to the dose of UK or the duration of UK infusion. A combination of thrombolysis and endovascular intervention can be of significant benefit in selected patients with extremity ischemia. However, complications are frequent and may be lethal.(ABSTRACT TRUNCATED AT 250 WORDS)