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Biomedical subjects

R H Dean

Publications and source records attributed to R H Dean.

At least 55 records · Page 3Linked to original sources
PubMed1989

A lack of coordination in the release of urinary lysosomal and brush border enzymes following renovascular surgery.

The urinary secretion of two lysosomal enzymes, N-acetyl-D-glucosaminidase (NAG, EC 3.2.1.30) and beta-glucuronidase (GLR, EC 3.2.1.31), and two brush border enzymes, alanine aminopeptidase (AAP, EC 3.4.11.2) and gamma-glutamyltransferase (GGT, EC 2.3.2.2), was examined in apparently healthy individuals and in patients before and after renovascular surgery for treatment of hypertension. Eight out of nine patients had elevated levels of at least one enzyme before surgery. The ranking in their frequency of elevation was NAG greater than AAP greater than GLR greater than GGT. In comparing the release of any two enzymes in apparently healthy individuals, the release was coordinated except for GGT and GLR. In individual patients following surgery the excretion of the lysosomal enzymes was highly coordinated whereas the release of the brush border enzymes was less coordinated. Comparisons of lysosomal to brush border enzyme activities revealed dissimilar release patterns between these two classes of enzymes. Analysis of variance over the entire hospitalization period showed that NAG/GLR (p = 0.42) and AAP/GGT (p = 0.12) did not vary significantly whereas all comparisons of lysosomal to brush border enzymes varied significantly (p less than or equal to 0.03). These results indicate that enzymes derived from different subcellular organelles, lysosomes or brush borders, have similar release patterns. However, the lack of a significant correlation between lysosomal and brush border enzyme excretion implies that the two processes are not interdependent. These studies further suggest that the transient pathophysiological changes that occur within renal cells following renovascular surgery affect these cellular components in different ways.

Acetylglucosaminidase↗
PubMed1989

Prophylactic closed suction drainage of femoral wounds in patients undergoing vascular reconstruction.

Prophylactic closed suction drainage has been advocated in a variety of surgical wounds, but its use in wounds involving vascular anastomoses has not been studied. Fifty patients undergoing lower extremity revascularization that required bilateral groin incisions were randomly assigned to have either the right or left side of the groin drained with a closed suction catheter. The contralateral wound was closed without drainage. Statistically there was no difference between wound closed with drains and undrained wounds in the occurrence of hematomas, seromas, lymphoceles, superficial infections, subcutaneous infections, or graft infections; although serious complications were more frequent in the drained wounds. Prophylactic closed suction drainage appears to offer no advantage over closure without drainage in wounds of the groin resulting from elective vascular operations.

Anastomosis, Surgical↗
PubMed1989

Management of renovascular hypertension in the elderly population.

This article summarizes our experience with the operative management of renovascular hypertension in a contemporary population of elderly patients. During a recent 18-month period 35 of 74 patients (47%) undergoing an operation for renovascular hypertension at our center were in their seventh (21 patients) or eighth (14 patients) decade of life (mean age, 68 years). There were 17 men and 18 women with blood pressures ranging from 176/90 mm Hg to 280/215 mm Hg (mean, 213/121 mm Hg). Twenty-seven patients (77%) had renal insufficiency (serum creatinine greater than or equal to 1.3 mg/dl). Nineteen patients had severe insufficiency (serum creatinine greater than or equal to 2.0 mg/dl), with five of these patients being dependent on dialysis. Thirty-three of 35 patients (94%) had evidence of organ-specific atherosclerotic damage as manifested by cardiac disease (72%), cerebrovascular disease (37%), or renal insufficiency (77%). Operative management consisted of unilateral revascularization in 17 patients (includes three contralateral nephrectomies), bilateral renal revascularization in 17 patients, and primary nephrectomy in one. Simultaneous aortic replacement was performed in nine patients. There were two operative deaths (5.7%) and two postoperative graft thromboses (4%). Hypertension was cured (three) or improved (27) in 30 of the 33 survivors (91%). Renal function was improved in six and worsened in two patients with severe non-dialysis-dependent renal insufficiency. Three of five patients who were dependent on dialysis before surgery were removed from dialysis after renal revascularization. On follow-up (mean, 10.3 months) we found that five patients had died. This article emphasizes the complexity of atherosclerosis in the current population presenting for operative management of renovascular hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Penetrating popliteal artery injuries in children.

Two children, aged 8 and 12, were seen recently at the Vanderbilt University Medical Center and Metropolitan Nashville General Hospital with gunshot injury to the popliteal artery. Both patients presented with late complications following missed penetrating injury to the popliteal artery. At presentation, distal pulses were palpable despite significant proximal arterial injury. Arteriography detailed traumatic popliteal artery aneurysms in both children, and an arteriovenous fistula in one child. These two children represent the youngest patients recorded in the surgical literature with gunshot trauma to the popliteal artery, subsequent formation of traumatic aneurysms, and an arteriovenous fistula. The increasing availability of guns and rifles in the household will likely increase the incidence of such injuries to children. As evidenced by these children, palpable pulses distal to an injury do not obviate the need for arteriography when arterial injury is suspected. Autogenous repair of the injured artery or reconstruction with autogenous vein graft is preferable for repair of vascular injuries in children.

Aneurysm↗
PubMed1988

Neurofibromatosis and renal artery stenosis: a case of familial incidence.

Hypertension as a result of proximal renal artery stenosis has been described in patients with neurofibromatosis, but a review of the English language literature showed no familial incidence of renovascular lesions in association with neurofibromatosis. We report a case of neurofibromatosis in a 24-year-old white woman with renovascular hypertension resulting from a proximal renal artery stenosis and poststenotic aneurysmal degeneration. Her sister, aged 38 years, presented similarly but without clinical evidence of neurofibromatosis. Both sisters had reversed saphenous vein bypass grafting for renal artery stenosis and showed no evidence of pheochromocytoma. Histologic examination of both surgical specimens revealed similar fibrodysplastic changes of the media and adventitia without abnormal neural tissue, findings consistent with those described in patients with neurofibromatosis.

Adult↗
PubMed1988

Phlegmasia cerulea dolens: therapeutic considerations.

Phlegmasia cerulea dolens (PCD) is a rare venous disorder that continues to be a major therapeutic challenge. We reviewed 16 cases of PCD treated during the past 15 years; 11 of the patients were male, and the average age of all the patients was 59 years. Malignant disease was the most common underlying condition (seven patients). Venous gangrene (VG) was present in seven extremities. Three treatment methods were used alone or in combination--intravenous heparin, venous thrombectomy, and thrombolytic therapy. Heparin was used initially in 13 patients; it yielded a successful result in seven (53%) patients, none of whom had VG. Venous thrombectomy was done in six patients; in three it was the primary procedure, in two it followed failure of heparin, and in one it followed failure of both heparin and thrombolytic therapy. Venous thrombectomy was successful in three (50%) patients, one of whom had early VG. Thrombolytic therapy was used on one occasion in conjunction with both heparin and venous thrombectomy, without benefit. Five patients died, all with VG, three after heparin only, one after heparin and venous thrombectomy, and one after all three treatment methods. Review of the 38 cases reported in the recent literature shows comparable results. These data suggest that nongangrenous forms of PCD respond well to systemic anticoagulation. Combination therapy using venous thrombectomy and heparin is indicated for severe ischemia, early VG, or failure of PCD to improve after six to 12 hours of heparin therapy. Phlegmasia cerulea dolens with VG is the lethal form of the entity and responds poorly to established therapy. Future therapeutic trials need to consider aggressive use of thrombolysis with or without thrombectomy.

Adult↗
PubMed1987

Failed percutaneous transluminal renal angioplasty: experience with lesions requiring operative intervention.

Percutaneous transluminal angioplasty (PTA) has received widespread publicity as a safe, simple, and successful alternative to operation for the management of renal artery stenoses and renovascular hypertension (RVH). Although, in our institution, the primary management of RVH remains operative revascularization, with more than 750 such procedures having been done, we have had the opportunity to manage a spectrum of PTA failures in nine patients during the last 5 years. These include (1) acute dissection of atherosclerotic lesions and occlusion of the distal renal artery requiring emergency operation; (2) unilateral perforation and bilateral thrombosis of fibrodysplastic branch renal artery lesions requiring staged ex vivo reconstruction; (3) cholesterol embolization and recurrence to total occlusion of orificial atherosclerotic lesions with loss of excretory renal function; (4) chronic dissection from repeated "temporarily successful" PTAs of medial fibrodysplastic lesions; and (5) rapid recurrence and acceleration of hypertension in a 17-year-old girl with congenital renal artery stenoses. In each instance operation was complicated by an intense perivascular inflammatory response from the previous PTA and required a more complex reconstruction than would have been needed originally. These sequelae argue for moderating enthusiasm for the use of PTA and for limiting its routine use to nonorificial atherosclerotic lesions and fibrodysplastic lesions restricted to the main renal artery. Orificial atherosclerotic lesions, branch fibrodysplastic lesions, and congenital stenoses have a high probability of failure, complications, or both when treated by PTA and should be considered for primary operative intervention.

Angioplasty, Balloon↗
PubMed1986

Management of vascular complications of bacterial endocarditis.

Peripheral arterial emboli that result from bacterial endocarditis may be silent or catastrophic. Cardiac surgical intervention may prevent embolism, but the guidelines for timing of intervention are unclear. An accepted approach is to intervene only if two episodes of peripheral embolism occur. Our recent experience suggests a more refined approach is in order. Eight children with active bacterial endocarditis have been treated with embolic complications. One patient with abdominal pain and GI bleeding was treated with heparin for multiple peripheral mesenteric emboli. Four patients had femoral embolectomies, one twice. Three patients developed embolomycotic aneurysms of the aorta in two cases and the common iliac in one; all were ruptured and two survived with staged reconstruction in one and extra-anatomic bypass in the other. Staph aureus and Strep viridans were the organisms involved most often. A review of the details of care in these patients leads to the following conclusions: angiographic survey reveals that most patients have multiple emboli; early embolectomy may prevent formation of infected aneurysms; Staph aureus infected patients are at risk for development of infected aneurysms; patients with large floppy vegetations in the left heart on echocardiography are at high risk for embolism; and 2 to 3 weeks from onset of endocarditis is the peak time for embolic risk.

Adolescent↗
PubMed1986

Blood pressure aberrations associated with carotid endarterectomy.

This report examines and reviews the frequency, potential causes and management of blood pressure aberrations in 100 consecutive carotid thromboendarterectomies. Reasons for operation and postoperative sequelae included: asymptomatic stenosis, transient ischemic attacks, non-hemispheric symptoms, amaurosis fugax, previous stroke, and evolving stroke. Hypertension (greater than or equal to 100 mmHg diastolic) occurred within 24 hours of operation in 37 instances (37%). Recognized causes included: manifestation of preoperative hypertension (19); carotid sinus denervation or transient mild cerebral edema (16); and massive cerebral edema in the two postoperative strokes of the series. Control of hypertension was most commonly managed by intravenous administration of nitroprusside. Profound immediate hypotension and bradycardia occurred in association with six procedures (6%). Accelerated carotid sinus nerve activity after removal of the noncompliant plaque was the probable cause of this reflex. Management included intravenous administration of parasympatholytic (atropine) and sympathomimetic (epinephrine) drugs. Aberrations of blood pressure after carotid TEA are common but with proper management do not represent a risk factor for perioperative stroke.

Adult↗
PubMed1986

Ex vivo renal artery reconstructions: indications and techniques.

Ex vivo renal artery surgery has been reported by several investigators and has extended the role of revascularization in the treatment of lesions previously managed by nephrectomy alone. Several techniques are available for use, and selection of the most appropriate method can be tailored to the specific anatomy being managed. Our total experience included 27 kidneys that have been managed by ex vivo renal artery reconstruction. Lesions managed in this manner include two kidneys with renal artery stenosis and renal tumors, one kidney with a congenital branch arteriovenous malformation, and 24 kidneys with branch occlusive or aneurysmal disease from fibromuscular dysplasia. Postoperative angiography was performed in 22 cases and defined successful revascularization without technical error in 20 cases. One operative death occurred as a result of myocardial infarction. One patient required reoperation to control bleeding, and two patients had temporary acute tubular necrosis during the postoperative period. Techniques employed included ex vivo repair with autotransplantation to the iliac system (six kidneys), mobilization and perfusion without transection of the renal vein (10 kidneys), and ex vivo perfusion and repair with replacement into the original renal fossa (11 kidneys). The authors believe this latter technique of reconstruction to be preferable to autotransplantation for the usual patient undergoing ex vivo repair of complex renovascular lesions.

Adult↗
PubMed1986

Mycotic embolism and embolomycotic aneurysms. Neglected lessons of the past.

During the past decade, nine patients with bacterial endocarditis have required management of mycotic emboli and/or aneurysms in this center. In these patients, 25 separate mycotic emboli or aneurysms were identified. Among these were four visceral, 11 lower extremity, one aortic, one hypogastric, and eight cerebral lesions. Multiple sites were involved in seven of the nine patients (78%). Presenting symptoms were secondary to acute expansion of mycotic aneurysms in three patients and secondary to rupture of aneurysms in four patients. Mycotic emboli produced cerebral infarction in two patients and acute ischemia in six patients. Asymptomatic mycotic aneurysms of the middle cerebral, hepatic, hypogastric, and profunda femoris arteries and asymptomatic emboli to the profunda femoris and tibial arteries were found during angiographic study. Management included resection alone (7 aneurysms), resection and graft replacement (2 aneurysms and 2 emboli), embolectomy (2), or observation. There was no mortality or loss of limb in these patients. This experience underscores the frequent multiplicity of mycotic emboli and/or aneurysms and stresses the importance of empiric angiographic survey to exclude silent yet potentially lethal visceral and cerebral mycotic foci in patients with bacterial endocarditis and peripheral emboli or aneurysms.

Adult↗
PubMed1986

Comparison of medical and surgical treatment of renovascular hypertension.

Controversy continues to surround the management of patients with hypertension secondary to renovascular disease. Older studies quote high mortality rates and graft thrombose rates with operative management and low rates of favorable blood pressure responses. These pessimistic reports have led to use of operation only when drug therapy does not provide adequate blood pressure control. This report summarizes these studies and provides more current information regarding changes in renal function during drug therapy and results of surgery and its potential role in both management of hypertension and control of progressive loss of renal function.

Age Factors↗
PubMed1985

Management of aortic thrombosis secondary to umbilical artery catheters in neonates.

During the past ten years, we have surgically managed seven neonates who developed total occlusion of the distal aorta due to umbilical artery catheters. All patients experienced symptoms of congestive heart failure. Five patients presented with severe hypertension, and all of these had aortorenal involvement: three infants had aortorenal thrombosis and two infants had infrarenal aortoiliac thrombosis with suprarenal extension of thrombus. Two infants had aortoiliac thrombosis with clot confined to the infrarenal aorta. Aortic thrombosis imposes an additional severe hemodynamic insult in these already seriously ill infants. Survival in this group of patients depends upon prompt recognition of this problem, effective surgical correction, and careful perioperative management. Our experience suggests that this diagnosis should be entertained in the infant presenting suddenly with congestive heart failure, hypertension, or lower limb ischemia after umbilical artery catheterization. The diagnosis is preferably confirmed by real-time ultrasound and/or radionuclide flow scan, although aortography may sometimes be necessary. Surgical management includes early transabdominal aortotomy with thrombectomy. Prompt thrombectomy resulted in the survival of six patients. One infant died in acute renal failure. Renal function and leg perfusion is satisfactory in the remaining patients, although one child required later operative correction of renovascular hypertension. Two additional patients needed prolonged postoperative antihypertensive therapy for 14 to 34 months before this problem resolved. Long-term follow-up is necessary for managing renovascular hypertension and monitoring lower extremity perfusion.

Aortic Diseases↗
PubMed1985

Chronic mesenteric ischemia in childhood and adolescence.

Chronic mesenteric ischemia is uncommon in the atherosclerotic age group but is particularly rare in childhood. Because of the nonspecific nature of symptoms produced and absence of pathognomonic findings by physical examination or by routine laboratory testing, its recognition is difficult and its true incidence is unknown. Four children treated for chronic mesenteric ischemia in our center demonstrated the spectrum of clinical presentations and operative considerations important in the management of this uncommon malady. Ages at presentation ranged from 30 months to 17 years. These presentations ranged from clinically silent ischemia in the 30-month-old child to evolving gastrointestinal infarction in the 17-year-old adolescent. Coexistence of abdominal aortic coarctation and/or renal artery stenoses was present in three of the four children. Successful bowel revascularization was achieved by superior mesenteric artery revascularization alone in three children (reimplantation in two and a bypass in one) and by multiple celiac and superior mesenteric artery bypasses in one. Delayed distal small bowel and proximal colonic resection was required in one child. This experience increases awareness that mesenteric ischemia does occur in childhood and is a rare but potentially lethal cause of abdominal complaints in children. Finally, the finding of both renal and visceral artery disease in three of the four patients underscores the need for adequate evaluation of mesenteric vessels before renovascular procedures are undertaken in this age group.

Adolescent↗
PubMed1985

Retrieval of renal function by revascularization. Study of preoperative outcome predictors.

Results of renal revascularization for retrieval of function in poorly functioning kidneys are variable, but criteria for prediction of benefit and patient selection for operation are ill-defined. This report examines preoperative parameters in 64 hypertensive patients who underwent successful revascularization of poorly functioning kidneys as defined by creatinine clearance less than or equal to 15 ml/min (measured by preoperative split renal function studies [SRFS]) or preoperative serum creatinine greater than or equal to 3.5 mg/dl (range: up to 8.9 mg/dl) to identify markers of value in prediction of a beneficial response in renal function. Ages ranged from 35 to 75 years. There were 35 men and 29 women. The renovascular lesion was atherosclerotic in 58 patients and fibrodysplastic in six. Total renal artery occlusion was present in 32 cases. No urine flow was detectable before surgery on SRFS from 13 kidneys. Kidney lengths ranged from 7.7 cm to 15.1 cm. Fifty-four unilateral and 10 bilateral revascularizations were performed. A beneficial blood pressure response to operation was observed in 94%. Benefit in excretory function was determined by comparison of preoperative and postoperative data which included SRFS parameters, renal length, serum creatinine, isotopically derived split functioning renal mass, and glomerular filtration rates. Overall, 56 patients could be classified in regard to functional response. Twenty-two patients received no or minimal benefit; nine patients received modest improvement, and 25 patients exhibited more marked improvement. Statistical evaluation of preoperative anatomic and functional parameters as predictors of functional response suggested that multiple variables influence the probability of function retrieval by revascularization. Useful among these predictive variables are the status of the distal vessel beyond the occlusion, the bilaterality of reconstructable disease in azotemic patients, the amount of residual renal mass available for revascularization, and the degree of hyperconcentration of nonreabsorbable solutes from the involved kidney after surgery.

Adult↗