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Biomedical subjects

H I Machleder

Publications and source records attributed to H I Machleder.

At least 37 records · Page 2Linked to original sources
PubMed1990

Massive splenomegaly. Superior results with a combined endovascular and operative approach.

Splenectomy for massive splenomegaly (drained splenic weight, greater than 1000 g) has an uncommonly high morbidity and mortality because of technical challenges and problems of hemostasis. In a group of 10 patients with massive splenomegaly due to myeloproliferative disorders (average splenic weight, 4193 g), we developed a management algorithm based on preoperative angiographic embolization of the splenic artery. Average operating time was 1.7 hours (range, 1 to 2.5 hours). Average blood loss was 528 mL; six of the 10 patients had blood loss less than 250 mL. There were four minor complications and one major complication (gastric ulcer requiring reoperation). There were no deaths in the perioperative period, and no patients required reoperation for hemorrhage.

Adult↗
PubMed1989

Treatment of Paget-Schroetter syndrome. A staged, multidisciplinary approach.

A comprehensive approach to management of Paget-Schroetter syndrome was developed and applied to 25 consecutive patients. We studied 14 men and 11 women with an average age of 29 years, 17 of whom were either competitive athletes or industrial workers with onset of symptoms related to physical stress. Venous compression or thrombosis at the thoracic outlet was demonstrated in all patients, with similar abnormalities in the contralateral vein visualized in 12 of 15 patients studied. Eight of 17 patients had evoked potential loss of the brachial plexus peak (N9), and 21 patients had stress compression of the subclavian artery. Osseous or musculotendinous abnormalities were documented in 18 patients. Excellent functional results were obtained when initial treatment with high-dose local thrombolytic agents (11 patients) was followed by anticoagulation. Transaxillary first rib resection (17 patients) and balloon angioplasty (3 patients) were used in selected patients with residual symptoms or venous compression.

Adolescent↗
PubMed1989

Intraoperative infusion of lytic drugs for thrombotic complications of revascularization.

Between August 1983 and December 1987, 23 patients received a 30-minute intraoperative, intraarterial infusion of streptokinase (seven patients) or urokinase (16 patients) because of residual thrombus or persistent ischemia or both after thromboembolectomy. Ages ranged from 21 to 77 years (mean, 58 years). In 15 patients intraoperative lytic therapy was part of the initial operation, whereas in eight patients intraoperative lytic therapy was performed during a secondary operation to treat thrombosis of a recently placed graft. Seven patients in the latter group had hypercoagulable conditions (five had heparin-induced thrombosis; one had protein C deficiency; one had polycythemia with thrombocytosis). Improvement after intraoperative lytic therapy was seen on angiography performed after infusion in 13 of 17 (76%) patients in whom angiography was performed both before and after intraoperative lytic therapy. Grafts in 12 of these patients remained patent without additional intervention, and in one graft thrombus formed again. In contrast, among four patients without angiographic evidence of improvement, thrombus formed again in four grafts (p less than 0.004). Intraoperative lytic therapy was considered successful in 74% of instances (17/23), including four of seven patients with hypercoagulable states. Three of six patients whose grafts failed had major amputations, whereas there were no amputations after successful infusions. Twelve patients were heparinized after intraoperative lytic therapy. Ten patients in this group were considered treatment successes, and two were considered treatment failures. Three of 11 patients not heparinized after intraoperative lytic therapy were considered treatment failures. Four hematomas occurred in the former group and none in the latter (p less than 0.03). No hematomas occurred in the heparin-induced thrombosis group in spite of anticoagulation with sodium warfarin (Coumadin). Only one hematoma occurred within 6 hours of intraoperative lytic therapy, and thus it was attributable to the infusion. We conclude that intraoperative lytic therapy is an effective adjunct to manage residual thrombus or persistent ischemia or both after lower extremity revascularization. Postinfusion angiography is of prognostic value. Heparinization after intraoperative lytic therapy seems beneficial but significantly increases the risk of bleeding complications.

Adult↗
PubMed1988

Cost of treating advanced leg ischemia. Bypass graft vs primary amputation.

We compared the hospital costs of 94 patients undergoing femoropopliteal bypass grafts with those of 53 patients undergoing primary amputation. The total cost of uncomplicated bypass surgery averaged +20,300, compared with +14,000 for uncomplicated below-knee amputation. However, including the cost of prosthesis and rehabilitation, the total cost of primary amputation was +20,400, equivalent to that of the bypass operation. Complications requiring revision of a bypass graft increased hospitalization by 4.5 days with the total cost rising to +28,700; complications that ended with major amputation added 15 hospitalization days and had an average cost of +42,200. In contrast, complicated below-knee amputation cost +40,600 and added 12.5 hospitalization days. There is therefore no cost-benefit in primary amputation when compared with arterial reconstruction, and cost should not be used to deny a patient the opportunity for limb salvage.

Amputation, Surgical↗
PubMed1988

Inflow failure of grafts originating in the axillary artery.

During the last three years we identified three distinct entities which compromised inflow and led to thrombosis of axillofemoral or axillopopliteal grafts. The first patient had recurrent thrombosis of a right axillopopliteal graft. Five thromboses were treated with thrombectomy and distal revisions; the last thrombosis was treated with simple thrombectomy because the patient had right thoracic outlet axillosubclavian artery compression in his usual sleeping posture. Conservative posture modification resulted in continued patency for two years until the patient's death. Stenosis of the subclavian or innominate artery accounted for multiple failures in three other patients. In one no significant preoperative upper extremity pressure difference was seen, whereas differences were noted with an open graft, suggesting a vascular steal at rest. In the second patient, preoperative balloon dilatation of an innominate lesion appeared successful, but the lesion recurred six months later with hemodynamic graft failure and exercise-induced vascular steal. The third patient had a significant kink of the axillary artery with eventual graft thrombosis secondary to "pulling" from the extraanatomic graft. We conclude that pre-and postoperative noninvasive testing, exclusion of thoracic outlet compression, and avoidance of a "pulled down" proximal anastomosis are important in preventing inflow failures of grafts originating from the axillary artery.

Aged↗
PubMed1988

Is the preferential use of polytetrafluoroethylene grafts for femoropopliteal bypass justified?

The objective of this review is to analyze the long-term results of femoropopliteal bypass done preferentially with polytetrafluoroethylene (PTFE) grafts in patients who presumably had saphenous vein available. The results are analyzed according to preoperative variables in an attempt to determine those instances in which PTFE grafts may be preferred for the first reconstruction and to identify those patients who benefited from vein preservation. From 1979 to 1985, 146 femoropopliteal bypass operations were performed in 120 patients with 6 mm PTFE grafts used preferentially. The results with follow-up at 5 years are analyzed by actuarial methods. The patency rate at hospital discharge was 100%. The overall primary patency rate at 5 years was 57%. Reconstructions above the knee (101) and below the knee (45) had significantly different 5-year patency rates (63% vs 44%, p less than 0.03). Sixty-two reconstructions done to alleviate disabling claudication had a 5-year primary patency rate of 69% and no amputations. Eighty-one reconstructions were done to treat critical ischemia with a 5-year patency rate of 49% and a 5-year foot salvage rate of 73%. When secondary operations were required to treat graft failures, the 4-year cumulative patency rate of the secondary reconstruction was 18% when performed with a prosthetic graft, in contrast to 70% when performed with the spared saphenous vein. We conclude that femoropopliteal reconstruction with PTFE grafts is a reasonable alternative for older patients with disabling claudication. Patients with critical ischemia will likely benefit from preservation of the vein with initial femoropopliteal reconstruction done with PTFE. Staged infrainguinal revascularization for foot salvage may improve present results. In this regard the sequence PTFE-then-vein carries a higher predicted patency rate than the sequence vein-then-PTFE.

Actuarial Analysis↗
PubMed1988

Can clinical evaluation and noninvasive testing substitute for arteriography in the evaluation of carotid artery disease?

The objective of this study was to prospectively assess the value of combining clinical assessment and noninvasive testing in predicting the spectrum of carotid bifurcation pathology, as subsequently proven by arteriography, in order to determine the safety and accuracy of performing carotid endarterectomy without angiography. A panel of eight specialists representing vascular surgery, neurology, and neurosurgery were presented with the history, physical findings, and noninvasive test results (GEE-OPG and duplex scan) of 85 patients. They were asked to make an anatomic prediction of the status of each carotid artery (170 arteries) as to whether the bifurcation was normal, ulcerated, had a hemodynamically significant stenosis, or was occluded. The predictions were then prospectively evaluated and correlated with angiographic findings; 159 of 170 (93.5%) carotid arteries were accurately characterized; 73 of 80 (91%) symptomatic carotid arteries and 86 of 90 (95.5%) asymptomatic arteries were correctly characterized; 61 of 61 (100%) stenoses of hemodynamic significance, nine of 14 (64.3%) ulcerations without stenosis, and 18 of 18 (100%) of total occlusions were accurately identified by the panel. Twenty-nine patients have subsequently had 32 carotid endarterectomies without angiography, and the predicted lesion was confirmed at the time of exploration. The combination of clinical assessment and noninvasive testing, particularly duplex scanning, when performed in a laboratory with validated accuracy may with defined qualification be safely used as a substitute for contrast angiography.

Aged↗
PubMed1987

Incidence and mechanism of post-carotid endarterectomy hypertension.

Hypertension following carotid endarterectomy occurs frequently but is poorly understood. Its occurrence has been correlated with an increased incidence of neurologic complication. We identified those factors that correlate with an increased incidence of post-carotid endarterectomy hypertension. The records of 100 patients who underwent carotid endarterectomy at UCLA Medical Center from November 1981 to September 1983 were examined. One hundred fifty variables were surveyed to determine those factors associated with this problem. Fifty-eight percent of the study patients developed post-carotid endarterectomy hypertension (an increase in systolic blood pressure greater than 35 mm Hg over baseline, and/or blood pressure requiring treatment with sodium nitroprusside). Of patients who developed this problem, 93% had diabetes mellitus, 75% received isoflurane anesthesia, 71% had peripheral vascular occlusive disease, 71% underwent ipsilateral transient ischemic attacks, and 65% had high-grade ipsilateral carotid stenosis. These variables have in common the loss of or interference with cerebral autoregulation. Central dysautoregulation may set the stage for a positive feedback mechanism that results in increased blood pressure. Anesthetic agents that do not interfere with cerebral autoregulation may reduce the incidence of this complication, and an aggressive treatment program may prevent neurologic complications.

Adult↗
PubMed1987

Perigraft seroma: clinical, histologic, and serologic correlates.

A 14 year retrospective study of perigraft seroma, defined as an enlarging sterile fluid collection at the site of a prosthetic graft, revealed well-documented cases in 5 of 118 extraanatomical bypasses (4.2 percent), 3 of 248 aortic reconstructive procedures (1.2 percent), and 1 of 395 femoropopliteal bypasses (0.3 percent). These nine cases involved four polytetrafluoroethylene and five Dacron grafts. There were five graft thromboses, one instance of limb loss, two graft infections, two deaths, and 13 separate surgical procedures related to the perigraft seroma. Histologic studies revealed a fibrous pseudomembrane lining the perigraft seroma wall and immature fibroblasts lining the graft. Sera from three patients with perigraft seroma, five patients with well-incorporated prosthetic grafts, and three healthy volunteer subjects were tested for in vitro evidence of fibroblast inhibition against fibroblast tissue cultures derived from the pseudomembrane of a perigraft seroma. Control fetal calf serum, sera from all three healthy subjects, and sera from all five patients with well-incorporated grafts allowed fibroblast proliferation. In contrast, sera from all three patients with perigraft seroma inhibited fibroblast growth. Furthermore, sera collected 1, 2, and 3 months after graft removal from one patient and serum collected 3 months after spontaneous resolution of a perigraft seroma from another patient failed to inhibit fibroblasts. We have concluded that patients with perigraft seroma have a high rate of graft and limb loss and require multiple reoperations. The pathogenesis of perigraft seroma appears to involve a humoral fibroblast inhibitor which prevents maturation and proliferation of perigraft fibroblasts, leading to poor graft incorporation. The decrease of inhibition below detectable levels after graft removal or spontaneous resolution of the perigraft seroma suggests that the graft may induce host production of the inhibitor. Effective therapy of perigraft seroma may include fibroblast modulation, removal of the inciting graft, or both.

Blood Vessel Prosthesis↗
PubMed1987

Somatosensory evoked potentials in the assessment of thoracic outlet compression syndrome.

To evaluate the assessment of thoracic outlet compression syndrome (TOS) by objective methods, we prospectively studied a group of 80 consecutive patients with disabling TOS who had been selected for surgical therapy. Comprehensive pre- and postoperative neurophysiologic tests were used and included electromyography, nerve conduction times, F wave determination, and somatosensory evoked potentials (SEPs) of median and ulnar nerves in neutral and stressed positions. Measurements were made of Erb's point peak (N9), cervical peak (P/N13), and cortical complex (N18-P22). Amplitude ratios were calculated for each side, and interpeak latencies were measured for N9-P/N13, P/N13-N18, and N9-N18. SEP results were abnormal on the affected side in 59 of 80 patients (74%); ulnar peak amplitudes were either less than 33% of median, reduced by more than 50% in the stressed position, or reduced by more than 50% when compared with the contralateral side. Of 64 patients studied pre- and postoperatively with SEP, 40 of 47 abnormal tests showed improvement, with 30 of these returning to normal values in the early postoperative period. Excellent clinical correlation was evident in 43 of these 47 patients (92%) who had pre- and postoperative tests; with relief of symptoms reflected in improved SEP, or continued symptoms explained by evidence of persistent or residual nerve dysfunction. The present methodology and criteria for test interpretation demonstrate that SEP can document the neurocompressive component of TOS and provide an objective assessment of pre- and postoperative clinical observations.

Action Potentials↗
PubMed1986

The anterior scalene muscle in thoracic outlet compression syndrome. Histochemical and morphometric studies.

Histochemical studies and morphometric fiber type analysis were done on biopsy specimens of anterior scalene muscle (ASM) from patients with thoracic outlet compression syndrome (TOS), without structural abnormality. Hypertrophy and atrophy factors were determined from muscle fiber histograms of ASM from controls, patients with TOS, and after scalene tenotomy. Scalene muscle from patients with TOS showed marked type 1 (tonic contracting) fiber predominance (85.1% +/- 5.1%) and type 1 fiber hypertrophy (55.6 +/- 2.7 microns). After tenotomy there is a reduction of type 1 fiber representation, selective atrophy in the type 1 fiber system (atrophy factor, 0.66 +/- 0.24), and increase of type 2 fibers. These distinctive changes indicate that ASM is uniquely structured in fiber composition to sustain prolonged contraction. The ASM in patients with TOS demonstrates an extraordinary adaptive transformation and recruitment response in the type 1 fiber system reflecting chronic increased tone or motor neuron stimulation. These observations form a basis for clarifying the structural and pathophysiologic changes in TOS.

Adult↗
PubMed1986

Relationship of extracranial carotid occlusive disease and central retinal artery occlusion.

Central retinal artery occlusion usually results in blindness. The association between central retinal artery occlusion and extracranial carotid disease has not been clearly delineated. We reviewed the case reports of 62 patients with central retinal artery occlusion, 25 of whom underwent carotid angiography as part of the diagnostic evaluation. Fourteen of the 25 (56 percent) were found to have ipsilateral extracranial carotid disease. These patients did not generally have carotid bruits and had normal noninvasive carotid tests. Ten patients underwent ipsilateral carotid endarterectomy; these patients had either embologenic ulcerated plaque or tight stenosis of the carotid artery. There were 11 patients who showed no abnormalities on angiography. Thirteen patients who did not undergo angiography showed clinical evidence of etiologic factors, including vasculitis, an embolism of cardiac origin, and trauma. The remaining 24 patients had no diagnostic workup. Follow-up data were available in six of those patients who underwent carotid endarterectomy for a mean of 34 months; no strokes were reported. In conclusion, over half of patients with central retinal artery occlusion who undergo carotid angiography will have a carotid lesion on the ipsilateral side. This suggests that central retinal artery occlusion is a significant marker for extracranial carotid disease and should be an indication for complete carotid evaluation.

Adolescent↗
PubMed1986

The superiority of synthetic arterial grafts over autologous veins in carotid-subclavian bypass.

From May 1964 to June 1983, 36 carotid-subclavian bypasses were done in 36 patients who had symptomatic lesions at the origin of the common carotid and/or subclavian arteries at the Center for Health Sciences of the University of California, Los Angeles. Ages ranged from 28 to 82 years (mean, 58 years). Eighteen bypasses were done with prosthetic grafts, 13 done with autogenous vein, and five were transpositions with primary anastomosis of the subclavian and carotid arteries. Follow-up was available on all patients and ranged from 9 to 156 months (mean, 51.5 months). The graft patency rate at 5 years determined by actuarial methods and documented by clinical examination, noninvasive evaluation, and/or arteriography was 94.1% for prosthetic grafts and 58.3% for vein grafts (p less than 0.01). The 5-year cerebrovascular accident (CVA) rate for patients with carotid-subclavian bypass done with prosthetic grafts was 6% in contrast to 39% for those with vein grafts (p less than 0.0545). All reconstructions done by transposition and primary anastomosis remain patent and there have been no late CVAs. We conclude that prosthetic grafts are the arterial substitute of choice in carotid-subclavian bypass. Transposition and primary anastomosis between the carotid and subclavian artery, when technically feasible, may be preferable to the use of free grafts in carotid-subclavian reconstruction.

Actuarial Analysis↗
PubMed1986

Aortic mural thrombus: an occult source of arterial thromboembolism.

During a 28-year period from 1955 to 1983, two cases of massive repetitive arterial thromboembolism from nonaneurysmal aortic mural thrombus were diagnosed antemortem and successfully corrected at the University of California, Los Angeles Medical Center. Within the same time period, 48 cases of nonaneurysmal aortic mural thrombus were identified in 10,671 consecutive autopsies (0.45% incidence). Eight of these patients had evidence of distal embolization (17%), and three had major thromboembolic occlusions, which were considered the proximate cause of death (6%). The latter three patients represented 9% of autopsy-confirmed deaths from peripheral arterial thromboembolism. The diagnosis was established in a 49-year-old man and a 51-year-old woman after a long course marked by recurrent arterial embolization. Despite multiple evaluations, which included angiography, the diagnosis remained elusive until clinical suspicion resulted in complete biplane aortographic survey. Although the morphologic characteristics of this lesion are quite striking, subtle angiographic changes and lack of familiarity with the clinical presentation contribute to the difficulty and infrequency of diagnosis. This unique lesion comprises an important segment of the so-called cryptogenic sources of arterial embolization and can be corrected by a definitive surgical procedure.

Aorta, Abdominal↗