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Biomedical subjects

L M Graham

Publications and source records attributed to L M Graham.

At least 73 records · Page 4Linked to original sources
PubMed1985

Reoperation for complications of renal artery reconstructive surgery undertaken for treatment of renovascular hypertension.

Seventy-two secondary operations for complications of prior renal artery reconstructive surgery were undertaken in 58 patients. This experience evolved from the management of 373 patients who underwent 425 primary operations for renovascular hypertension. Secondary operations were performed 10 times in pediatric patients following 42 primary procedures (24%); 44 times in adult fibrodysplastic patients following 199 initial operations (22%); and 18 times in atherosclerotic patients after 184 primary operations (10%). The overall reoperation rate was 15.5% (58 of 373 patients). Reoperation typically followed persistent or recurrent hypertension caused by graft thromboses, perianastomotic graft narrowing, or progressive nonanastomotic graft stenoses. Aneurysmal deterioration of vein grafts was an uncommon reason for reoperation. Secondary reconstructions included nephrectomy (31), bypass with vein grafts (15) or prosthetic grafts (8), angioplasty or reimplantation (12), thrombectomy (4), and operative dilation (2). Benefits regarding hypertension control were afforded 91% of these patients. One death occurred among the 72 reoperations, representing a 1.4% operative mortality rate. Reoperative renal artery reconstructive surgery for complications of renal revascularization may present formidable technical problems. Early diagnosis and prompt reoperation with exacting vascular surgical techniques are most likely to provide optimal results.

Adolescent↗
PubMed1985

Inferior mesenteric artery aneurysms.

Two patients were treated for asymptomatic aneurysms of the inferior mesenteric artery during reconstructive operation for infrarenal aortic disease. These lesions were discovered incidentally during arteriographic study in one case and during operation in the second case. Including these two patients, the number of reported inferior mesenteric artery aneurysms now totals 13. The etiology, manifestations, and treatment of the currently reported aneurysms are compared with eight previously published cases in which detailed clinical data were presented. Although the natural history of these rare aneurysms remains undefined, operative intervention appears appropriate for all mycotic lesions and certain other aneurysms, such as those in patients undergoing aortic operation.

Adult↗
PubMed1984

Intermittent claudication. Current results of nonoperative management.

We reviewed the clinical course of 91 men with mild intermittent claudication who had been followed up for at least six months without operation. During 2.5 years' mean follow-up, 60% of the patients had more severe claudication. Actuarial analysis revealed an annual mortality of 4.5% and an annual operation rate of 9%. Historical factors, including age, race, smoking, exercise, diabetes, hypertension, and the ankle-brachial index (ABI), were analyzed to determine if these variables could predict clinical outcome. Only cigarette smoking, exercise, and the ABI were significant in this regard. Patients who had smoked at least 40 pack-years had an operation rate 3.3 times higher than those who smoked less. Major daily exercise was associated with stable claudication. The initial ABI did not correlate with clinical outcome. A subsequent decrease in the ABI of at least 0.15, however, was associated with an operation rate 2.5 times higher and a symptom progression rate 1.8 times higher than patients without this change in the ABI. When regression analysis was used, the preceding variables were only 63% to 79% accurate in predicting the clinical outcome of individual patients. Careful follow-up of patients with intermittent claudication is therefore recommended to allow timely operative intervention when required.

Adult↗
PubMed1984

Platelet reactivity in vivo in dogs with arterial prostheses seeded with endothelial cells.

This study was designed to assess platelet activity in vivo with vascular prostheses seeded with endothelial cells to determine the time course for development of thromboresistance and to test the ability of prostheses to produce prostacyclin. Sixteen dogs were randomly allocated to receive seeded (experimental group) or unseeded (control group) velour Dacron aortic prostheses. Serial measurements of platelet survival were performed to assess platelet interaction with prostheses in vivo, and platelet serotonin was monitored as an index of platelet release in vivo. After placement of prostheses, dogs in the experimental group had rapid normalization of platelet survival, with most having normal platelet survival at 4 to 8 weeks after surgery. In contrast, most control animals had reduced platelet survival throughout the 12 week period of study. Significant differences between groups in mean platelet survival were noted at 8 weeks after surgery (p less than .005) and in mean platelet serotonin at 12 weeks after surgery (p less than .05). Luminal surface production of 6-keto-PGF1 alpha from seeded prostheses was similar to aortic production and significantly greater (p less than .05) than that of control prostheses. Gross thrombus was present on 6.0 +/- 3.4% of the prosthetic surface in experimental animals in comparison to 26.6 +/- 19.2% in controls (p less than .005). The results of these studies document accelerated nonreactivity with platelets of seeded prostheses due to rapid coverage with endothelium possessing a normal ability to produce prostacyclin.

Animals↗
PubMed1984

Atherosclerotic extracranial carotid artery aneurysms.

Twenty-four atherosclerotic extracranial carotid artery aneurysms were encountered in 21 patients during a 25-year period. These represented 46% of all extracranial carotid artery aneurysms diagnosed at the University of Michigan during this period. Neurologic symptoms including amaurosis fugax, transient ischemic attacks, and stroke were present in 50% of the patients. An asymptomatic pulsatile neck mass occurred in 33%. Surgical therapy was undertaken for 18 aneurysms, and nonoperative treatment was pursued in the remaining six aneurysms. Operative therapy included 14 aneurysmectomies and four aneurysmorraphies. There were no surgical deaths. Transient perioperative neurologic deficits affected three of these patients (17%), and one individual (5%) experienced a permanent deficit. Transient cranial nerve deficits occurred in three patients (17%), and a permanent deficit was noted in one patient (5%). During a 7.6-year follow-up period no late strokes occurred among patients who were operated on. Nonoperative therapy was associated with three ipsilateral strokes during a mean follow-up period of 6.3 years. Atherosclerotic extracranial carotid artery aneurysms were associated with an exceptionally high stroke rate (50%) if treated nonoperatively. Prevention of late stroke justifies surgery, although perioperative neurologic deficits may accompany this therapy more often than with nonatherosclerotic carotid artery aneurysms.

Aged↗
PubMed1983

Limb-threatening potential of arteriosclerotic popliteal artery aneurysms.

Eighty-eight popliteal artery aneurysms were diagnosed in 59 men and two women (mean age 67 +/- 10 years). Bilateral aneurysms affected 27 patients (44%). Aneurysm diameter ranged from 1.3 to 12 cm (mean 4 +/- 2.6 cm). Most aneurysms were symptomatic (55%). Dominant symptoms included rest pain (19%), claudication (14%), local pain (13%), and gangrene (9%). The remainder of the aneurysms were asymptomatic (45%). Aneurysm thrombosis occurred in 24% of extremities. Associated aneurysms involved the abdominal aorta (62%), iliac artery (36%), and femoral artery (38%). Aneurysms that caused local pain were larger (6.2 +/- 1.9 cm) than asymptomatic aneurysms (2.9 +/- 2.1 cm, P less than 0.01). Aneurysms smaller than 2 cm were more likely to be asymptomatic than larger aneurysms (P less than 0.05). Operative intervention was undertaken for 56 aneurysms, with aneurysmal exclusion or excision with arterial reconstruction performed most often. Four primary and five secondary major amputations were associated with thrombosed aneurysms, compared to no amputations with asymptomatic aneurysms (P less than 0.01). Thirty-two aneurysms were not treated surgically. Limb loss resulted from ischemic complications which developed in 18% of aneurysms treated without operation. The duration of follow-up for patients who had operation and those who did not averaged 62 months and 25 months, respectively. Operative treatment for all bland popliteal artery aneurysms appears justified if complications leading to major amputation are to be avoided.

Adult↗
PubMed1982

Extracranial internal carotid artery dissections: noniatrogenic traumatic lesions.

Noniatrogenic traumatic extracranial internal carotid artery dissections were encountered in six patients (five men and one woman) 31 to 62 years old. All but one had overt cerebral ischemia manifest by paresis (three), sensory deficits (three), aphasia (three), or amaurosis fugax (two), One patient had an asymptomatic carotid artery bruit. Cerebral arteriography established the diagnosis in all cases. Internal carotid artery impingement between the mandible and transverse processes of the second and third cervical vertebrae, or undue stretching over these vertebral structures, were the most likely primary mechanisms of injury. Secondary complications, a result of distal thromboembolism, were evident in two patients. Direct cerebral revascularization, staged internal carotid artery constriction and ligation, as well as intensive nonoperative therapy were valid therapeutic options. There were no deaths. Treatment relieved transient ischemic symptoms or arrested progression of established neurologic deficits in each case. In select patients, early surgical intervention may lessen attending neurologic sequelae.

Adult↗
PubMed1982

Enhanced patency of small-diameter, externally supported Dacron iliofemoral grafts seeded with endothelial cells.

Fourteen adult foxhounds underwent bilateral iliofemoral bypasses with externally supported, knitted Dacron grafts measured 4 mm in internal diameter and 10 cm in length. These conduits were preclotted with 10 ml of blood mixed with 0.5 ml of culture medium. Autologous endothelial cells, enzymatically derived from external jugular veins, were added to blood and medium used to preclot one graft in each dog. The other, unseeded graft served as a control. Grafts were anastomosed, end to end, to the iliac and femoral arteries. All dogs received dipyridamole, 50 mg twice a day for 4 days preoperatively, and aspirin, 5 grains four times a day for 1 day preoperatively. Both drugs were continued 14 days after operation. Grafts were removed from three dogs at 2 and 4 weeks and from four dogs at 8 and 16 weeks. All grafts were patent at 2 weeks during drug administration. Cumulative patency rates beyond 2 weeks were 73% in 11 seeded grafts and 27% in 11 control grafts, a statistically significant difference (P = 0.03). Seeded grafts were completely surfaced with a monolayer of endothelium between 2 and 4 weeks. Small-graft patency appeared related to evolution of endothelial surfaces, the development of which was clearly facilitated by seeding with autologous endothelium.

Animals↗
PubMed1982

Expanded polytetrafluoroethylene vascular prostheses seeded with enzymatically derived and cultured canine endothelial cells.

Thirteen adult dogs underwent thoracoabdominal bypass operations with 6 or 10 mm expanded polytetrafluoroethylene (PTFE) grafts 25 to 30 cm long. Eight experimental grafts were seeded with cultured autologous endothelial cells prior to implantation. Five unseeded grafts served as controls. Endothelial cells, derived from external jugular vein segments using 0.1% trypsin and 0.5% collagenase solutions, were cultivated for 14 days prior to seeding. Grafts were studied at 2 and 4 weeks after implantation. Endothelial linings in control grafts were restricted to limited anastomotic pannus ingrowths, never exceeding 10% of the graft surface. Experimental grafts demonstrated an endothelial surface coverage averaging 64% and 91% at 2 and 4 weeks, respectively. Generation of an early lining of endothelium in expanded PTFE grafts is possible in a canine model using cultured autologous cells.

Animals↗
PubMed1981

Developmental occlusive disease of the abdominal aorta and the splanchnic and renal arteries.

Developmental occlusive disease of the abdominal aorta and the renal and splanchnic arteries represent an unusual vascular condition. When unrecognized or untreated this disease is associated with premature death, usually from severe secondary hypertension as a consequence of renovascular stenotic lesions. Strong circumstantial evidence indicates that developmental abnormalities occurring during the fetal union of the two dorsal aortae account for most of the occlusive lesions affecting the abdominal aorta and its visceral branches in these patients. Complete arteriographic studies are necessary to confirm and accurately delineate the disease process. Surgical treatment, which often encompasses complex vascular reconstructive efforts, affords excellent results when carefully planned and executed.

Adolescent↗
PubMed1980

Splanchnic arteriosclerotic disease and intestinal angina.

Twenty-three patients (13 women and ten men, 33 to 73 years old) underwent reconstruction of 33 major splanchnic arteries for relief of symptomatic intestinal ischemia. All patients experienced postprandial abdominal pain and lost weight (average, 12.8 kg). Arterial reconstructions (32 bypass procedures and one endarterectomy with patch-graft arterioplasty) were undertaken with both autogenous saphenous vein (24) and prosthetic condults (nine). Revascularizations involved the superior mesenteric (21), celiac (five), hepatic (four), splenic (two), and inferior mesenteric (one) arteries. There were four postoperative deaths; three occurred after emergent secondary attempts at intestinal revascularization. All of the 19 patients who survived benefited from operative intervention.

Abdomen↗
PubMed1980

Clinical significance of arteriosclerotic femoral artery aneurysms.

One hundred seventy-two arteriosclerotic femoral artery aneurysms in 100 male patients, 47 to 91 years old, were evaluated. They were bilateral in 72% of the patients, and were associated with aortoiliac aneurysmal disease in 85% and with popilteal artery aneurysms in 44%. Femoral artery aneurysms were asymptomatic in 40 patients. Thirteen patients with thromboembolic episodes and two with rupture had ischemic limbs. Thirty-eight patients underwent primary operation for 50 femoral aneurysms, including 36 lower extremity arterial reconstructions, ten aortofemoral bypasses, one arterial ligation, and three amputations. Two operative deaths occurred, both associated with concomitant aortic surgery. Only three of 105 aneurysms in 58 patients followed nonoperatively were associated with later major limb-threatening complications. The low complication rate attending small, bland aneurysms justified nonoperative management. Large or symptomatic aneurysms warrant early operative intervention.

Aged↗