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Biomedical subjects

R J Stoney

Publications and source records attributed to R J Stoney.

At least 19 recordsLinked to original sources
PubMed1992

Surgical recanalization of occluded peripheral arteries.

This article, reflecting on the surgical recanalization of occluded peripheral arteries, has exposed the very essence of vascular surgery. Only the pioneering cardiac anomalies repaired by Gross (patent duct arteriosus, 1938), Blalock and Taussig (tetralogy of Fallot, 1944), and Crafoord and Nylin (coarctation, 1945) and the legendary aortic grafting operations of Oudot (occlusion, 1950) and Dubost and coworkers (aneurysm, 1951) are not a part of this article. The contributions to surgical recanalization of the occluded peripheral arteries are numerous. Some are well conceived, and others are innovative. Perhaps the most significant technique of all, endarterectomy itself, began purely as a serendipitous event. The startling impact of dos Santos' revolutionaly "disobliteration" was realized at once. Intimal injury during the operation did not cause inevitable thrombosis, as historically taught. Thus, all vascular interventions, either endarterectomy, graft repair, or the newer endovascular techniques discussed in this issue, would not have been developed without the understanding of the tolerance of the human intima to injury. Thromboendarterectomy, the basis of surgical recanalization of occluded arteries, unlocked the mystery of arterial rethrombosis after intervention. Recognizing these crucial facts, it will have a lasting place in the expanded discipline of vascular disease and its treatment. Dos Santos, the European founder of endarterectomy, and Wylie, the American pioneer and proponent of endarterectomy, were great friends in life (Fig. 4) and would certainly be pleased to see the further development of technology aimed at the treatment of atherosclerotic obstruction of the peripheral arteries.

Arterial Occlusive Diseases↗
PubMed1992

Circumferential venolysis and paraclavicular thoracic outlet decompression for "effort thrombosis" of the subclavian vein.

Effort thrombosis of the subclavian vein (Paget-Schroetter syndrome) has long been considered a primary thrombotic process, but recent experience suggests that it may commonly result from repeated mechanical compression. Increased awareness of the pathophysiology of this syndrome can allow timely, improved diagnostic screening and the use of specific surgical intervention to relieve the venous consequences. During the past 15 years we have treated six patients with mechanical compression in the thoracic outlet causing surgically correctable venous occlusive problems. There were four men and two women with an average age of 38 years (range 26 to 53 years). All patients exhibited pain, swelling, and cyanosis of the upper extremity, with worsening venous congestion on abduction of the arm. Five of six patients were originally treated for effort thrombosis of the subclavian vein with arm elevation and anticoagulation; two also underwent immediate thrombolytic therapy with urokinase. Venography was prompted in each case by positional symptoms during follow-up and showed irregular stenosis of the subclavian vein adjacent to the first rib. All patients underwent extended first rib resection and circumferential venolysis (one patient underwent bilateral procedures); one was performed through a transaxillary approach, two through a supraclavicular approach, and four through a new, "paraclavicular" approach. All subclavian veins appeared normal after venolysis. Five of six patients also underwent complete scalenectomy and brachial plexus neurolysis. In each patient, venous and neurogenic symptoms resolved and venography confirmed a patent subclavian vein, with follow-up ranging from 11 months to 13 years (mean 3.8 years).

Adult↗
PubMed1991

Comparison of the findings on preoperative dipyridamole perfusion scintigraphy and intraoperative transesophageal echocardiography: implications regarding the identification of myocardium at ischemic risk.

The evidence of myocardium at potential ischemic risk on preoperative dipyridamole perfusion scintigraphy was compared with that of manifest ischemia on intraoperative transesophageal echocardiography in 26 patients at high risk of a coronary event undergoing noncardiac surgery. The clinical outcome was also assessed. Induced intraoperative wall motion abnormalities were more common in patients and myocardial segments with, than in those without, a preoperative reversible perfusion defect (both p less than 0.05). Conversely, a preoperative reversible perfusion defect was more common in patients and segments with, than in those without, a new intraoperative wall motion abnormality (both p less than 0.05). Six patients, five with a reversible scintigraphic defect but only three with a new wall motion abnormality, had a hard perioperative ischemic event. Events occurred more often among patients with, than in those without, a reversible perioperative scintigraphic defect (5 [33%] of 15 vs. 1 [9%] of 11) but this difference did not reach significance (p = 0.14), probably owing to the sample size. Intraoperative wall motion abnormalities were all reversible and did not differentiate between risk groups; these findings were possibly influenced by treatment. These preliminary data support the known relation between reversible scintigraphic defects and perioperative events and identify another manifestation of ischemic risk in the relation between reversible scintigraphic defects and induced intraoperative wall motion abnormalities. The value of intraoperative echocardiography in identifying ischemia and guiding therapy in patients with a reversible scintigraphic abnormality should be further assessed.

Coronary Disease↗
PubMed1991

Chronic visceral ischemia. Three decades of progress.

Symptomatic visceral atherosclerosis is a major surgical challenge because of its life-threatening course and the complexity of its definitive operative treatment. Evolution in the operative approach to the visceral aorta and progress in the intraoperative management of patients undergoing complex vascular reconstructions prompted a review of the authors' cumulative experience in the surgical management of chronic visceral ischemia. Among all patients undergoing visceral revascularization at the University of California, San Francisco during the past three decades, 74 patients were identified whose primary reconstruction used transaortic endarterectomy (TA TEA) (n = 48) or antegrade bypass (AB) (n = 26), the authors' preferred revascularization techniques. The two treatment groups were comparable in gender distribution, age, presenting symptoms, and physical findings, although the amount of preoperative weight loss was greater in the AB group (35.8 +/- 19.5 versus 22.4 +/- 12.0, p = 0.003). The groups were also comparable in the prevalence of atherosclerosis risk factors, symptomatic vascular disease at other sites, and previous vascular operations. However associated renal artery atherosclerosis was slightly greater in the TA TEA group (58.3% versus 23.1%, p = 0.07) when compared to the AB group. Antegrade bypass was usually performed transabdominally (88.5%), while TA TEA was approached thoracoretroperitoneally (75.0%). Celiac revascularization was almost universal in both treatment groups, but the TA TEA group underwent significantly more frequent superior mesenteric artery (SMA) revascularization (93.8% versus 46.2%, p = 0.0001) and slightly more frequent inferior mesenteric repair (18.8% versus 3.8%, p = 0.07) than the AB group. In addition the frequency of combined renal and visceral repair (25.0% versus 0.0%, p = 0.01) as well as combined aortic, renal, and visceral repair (22.9% versus 3.8%, p = 0.03) was significantly greater in the TA TEA group. The obligatory interval of renal and visceral ischemia did not differ between the two approaches. The perioperative mortality rate was 12.2% and was the same for TA TEA (14.6%) and AB (7.7%). Overall the incidence of complications was the same with either operative approach, although patients in the TA TEA group tended to have multiple complications (17.1% versus 0.0, p = 0.03) and all significant pulmonary complications occurred in this group. Two patients were lost to follow-up. The cumulative percentage of patients who remained asymptomatic following AB or TA TEA was (respectively) 95.8% and 97.3% at 1 year and 86.5% and 86.1% at 5 years. Both of these operative approaches provide durable symptom relief with acceptable operative morbidity and mortality rates.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1991

The role of arterial reconstruction in spontaneous renal artery dissection.

Spontaneous renal artery dissection is an uncommon cause of renovascular hypertension, usually associated with fibromuscular dysplasia. Among reported nonautopsy cases (N = 80), arterial reconstruction has seldom been attempted (N = 21) and the outcome has frequently been poor (48% clinical failure rate). This is attributed in part to the frequent involvement of renal artery branches by the dissection. Furthermore, the report of spontaneous reversion to normotension among patients treated medically has also clouded the role of surgery in this disease. Since progress in the technique of renal artery repair now allows successful treatment of anatomically complex lesions, we reviewed our experience with arterial reconstruction in the management of spontaneous renal artery dissection to determine the frequency of and factors correlating with cure after operative repair. Ten patients (eight men, two women; mean age, 39.3 +/- 5.9 years) were admitted with severe hypertension (10/10), often associated with neurologic symptoms, hematuria, or flank pain (8/10). Serum creatinine was elevated in only two patients. Angiography demonstrated changes consistent with fibromuscular dysplasia in 7 of 10 patients and evidence of dissection in 6 of 10. Bilateral disease was present in three patients. Only five patients had a single renal artery on the involved side. The dissection extended into the primary branches in 8 of 10 patients and involved both renal arteries in four of the five patients with two arteries. Histologic study confirmed fibromuscular dysplasia in six and intramural dissection in all operative specimens. Five patients underwent revascularization (in one case requiring the ex vivo technique), with use of hypogastric artery as a conduit in four of five or resection and primary reanastomosis in one of five. Three patients became normotensive, and two returned to their previous level of blood pressure control. Follow-up averaged 14.5 years. Two patients underwent nephrectomy after exploration demonstrated nonreconstructible vessels, and two underwent nephrectomy when intraoperative assessment of the kidney showed that revascularization had failed to adequately reverse extensive renal ischemia. After a mean follow-up of 14.6 years these patients remain normotensive, although two require antihypertensive medications. One patient was treated medically and is currently hypertensive off all medications. Nine of 10 patients have maintained a normal serum creatinine during follow-up. We conclude that renal revascularization is frequently successful in spontaneous renal artery dissection (five of seven, 71.4%) and results in sustained relief of hypertension with maximal conservation of renal tissue. This is important because of the young age at onset and the not infrequent occurrence of bilateral fibromuscular dysplasia, and even of dissection.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

Intraoperative use of ultrasound in arterial surgery.

Technical perfection is the goal of any arterial reconstruction so as to avoid postoperative complications. Experimental and clinical studies have clearly shown that these operations are imperfect and that some form of intraoperative surveillance is required to decrease the incidence of correctable technical defects. Ultrasound technology is uniquely suited for this role. This article describes the distinct advantages of duplex ultrasound for the intraoperative monitoring of vascular reconstructions.

Arterial Occlusive Diseases↗
PubMed1990

Recurrent carotid stenosis: a consequence of local or systemic factors? The influence of unrepaired technical defects.

To determine the influence of unrepaired technical defects as well as systemic risk factors for atherogenesis on carotid artery healing after endarterectomy, we conducted a prospective study using intraoperative duplex scanning with spectral analysis to establish the initial status of the artery (N = 131 arteries), and then we studied these vessels at regular postoperative intervals with the same technique (N = 108 arteries, 265 studies). The vessels were divided into the operated and nonoperated segments of the common, internal, and external carotid arteries, and both intraoperative image and flow data were tabulated by artery segment. The technical factors that were analyzed included defect size, defect type, adjacent segment defects, number of defects, shunt use, vessel reopening, and peak, mean, and end-diastolic frequency and velocity. The systemic risk factors studied were sex, hypertension, diabetes, smoking, randomly drawn total serum cholesterol and triglyceride levels, and perioperative aspirin and dextran use. Data were analyzed by linear logistic regression analysis. Among the technical factors, only intraoperative defect size was significantly associated with risk of recurrent stenosis (p = 0.0175). Although any defect size adversely affected the condition of the vessel during follow-up, the magnitude of this effect was small for smaller defects (size category 1: less than or equal to 40% stenosis or flap length less than or equal to 25% of vessel diameter). The systemic factors that were associated with risk of recurrent stenosis were hypertension (p = 0.0002), smoking (p = 0.0016), and randomly drawn total serum cholesterol level (p = 0.0116). The fact that the operated segments consistently fared worse during follow-up than did the nonoperated segments (p = 0.0044) undoubtedly reflects the inevitable trauma of the endarterectomy, but also emphasizes the important contribution of systemic risk factors in recurrent carotid stenosis. Risk factor modification may be the most effective method of ensuring the durability of carotid endarterectomy.

Carotid Artery Diseases↗
PubMed1990

Clinical spectrum of symptomatic external iliac fibromuscular dysplasia.

External iliac fibromuscular dysplasia is a rare and usually asymptomatic disorder. We report eight symptomatic patients seen over a 15-year period and review pathophysiologic mechanisms accounting for the three following distinct lower extremity ischemic sequelae: (1) Emboli--episodic focal digital ischemia (blue toe) was seen in three patients. Resection and primary anastomosis of focal iliac ulcerative fibromuscular dysplasia (one patient) or resection and replacement (two patients) removed the embolic source and relieved the symptoms. (2) Chronic ischemia--gradual onset of full leg claudication in four patients was treated by operative graduated intraluminal dilation in three patients and prosthetic bypass in one. Arteriography subsequently showed a remodeled lumen in the three patients who underwent dilation. (3) Dissection--acute onset leg ischemia resulted from presumed dissection of the external iliac segment. After 4 months of conservative management of antiplatelet agents and exercise, symptoms resolved completely, and arteriogram showed spontaneous restoration of a normal lumen in the dissected segment. The clinical presentation of fibromuscular dysplasia may mimic other arterial processes such as atherosclerosis. Diagnosis is made only by arteriography with specific magnification views of the external iliac arteries and careful surveillance of the renal arteries. Appropriate treatment should be tailored to the clinical presenting symptom. For microembolic disease, resection and replacement are required. For chronic ischemia, intraluminal dilation is generally sufficient and durable and has proved to be a simpler and acceptable alternative to replacement or bypass. In acute dissection, surgical intervention may be deferred if the limb is viable to allow spontaneous healing and remodeling. Persistent symptoms may be the only indication for intervention in this ischemic manifestation of external iliac fibromuscular dysplasia.

Aged↗
PubMed1990

Infrarenal aortic occlusion: does it threaten renal perfusion or function?

Proximal propagation of aortic thrombus with resultant impaired renal perfusion has been considered a significant risk of untreated infrarenal aortic occlusion. To investigate this question, we studied 52 patients surviving 1 year or more after surgical interruption of the infrarenal aorta in the course of treatment of aortic graft infection. Blood pressure, renal function, and renal artery anatomy were studied before and after aortic interruption. Preoperatively, 20 patients (38.4%) had treated hypertension, and 11 (21.2%) had impaired renal function (creatinine greater than 1.3 mg/dl). In 46 patients (88.4%) with angiography before aortic interruption, 31 (67.4%) had normal renal arteries, whereas 15 (32.6%) demonstrated renal artery stenosis of less than or equal to 50% (N = 10) or greater than 50% (N = 9). Concomitant renal revascularization (N = 3) or nephrectomy (N = 1) were rare. All patients were monitored after surgery for a mean period of 39.2 months. Thirty-three (63.5%) remain alive and well; 19 (36.5%) have died of causes not related (N = 15) or indirectly related (N = 4) to the original graft infection. Forty-eight patients (92.3%) had late assessment of their blood pressure (N = 44, mean follow-up of 31.0 months) and/or renal function (creatinine) (N = 42, mean follow-up of 26.1 months). Follow-up aortography in 21 patients (40.4%, mean interval of 27.7 months) demonstrated no instance of suprarenal propagation of aortic thrombus. During follow-up 41 patients (78.8%) had no change in either their blood pressure or serum creatinine. Seven patients (13.5%) developed worsening hypertension (N = 3) or a rising creatinine (N = 4).(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta, Abdominal↗
PubMed1989

Altered pharmacokinetics of antibiotics during vascular surgery.

Prophylactic antibiotics significantly decrease the incidence of infection in various surgical procedures. Although antibiotics must be administered preoperatively to be effective, it is unknown whether therapeutic concentrations are necessary throughout the operation to prevent infection. Furthermore, the pharmacokinetics of antibiotics during surgical procedures is not well understood. Several factors, including blood loss, fluid redistribution, and changes in renal blood flow may alter the pharmacokinetic disposition of the antibiotic. In a controlled investigation of intraoperative antibiotic pharmacokinetics, cefamandole was studied in eight patients undergoing elective surgery of the abdominal aorta and peripheral vasculature. Both elimination half-life (67 +/- 19 minutes versus 93 +/- 23 minutes) and the volume of distribution (16.8 +/- 5.3 liters versus 25.2 +/- 11.9 liters) increased when compared with the preoperative state. The increased volume may be due, in part, to redistribution of fluid. Plasma concentrations of antibiotic were low at the time of graft placement in those patients with normal renal function. Additional antibiotic dosing may be warranted prior to prosthesis insertion in these patients.

Aorta, Abdominal↗
PubMed1989

The elusive isolated hypogastric artery aneurysm: novel presentations.

Isolated aneurysms of the internal iliac artery are rare. Their anatomic location makes them true pelvic aneurysms and they may grow to a large size undetected. Their late recognition may be prompted by rupture or symptoms related to compression of neurologic, gastrointestinal, genitourinary, or venous structures. We have encountered three isolated hypogastric artery aneurysms with unique presentations. In one patient with bilateral isolated hypogastric artery aneurysms, one ruptured into the bladder, and at a later time the other caused ureteral obstruction. Another patient had obturator neuropathy as a result of his aneurysm. In the patient with large bilateral aneurysms, one was detected by rectal examination, and the other was found by palpation of the abdomen. The second patient with a smaller aneurysm required examination of the pelvis by CT scanning to establish the diagnosis. Awareness of the existence of these lesions is required to identify such patients who describe symptoms uncommonly associated with abdominal aneurysms. Operative management consisted of exclusion of the aneurysm and partial or complete aneurysmorrhaphy with preservation of iliac arterial flow to maintain extremity perfusion. Recovery was complete in each instance. A review of published cases is presented.

Abdomen↗
PubMed1989

Renal endarterectomy through the transected aorta: a new technique for combined aortorenal atherosclerosis--a preliminary report.

The optimal surgical management of combined aortic and renal atherosclerosis has not been defined. A modified technique of renal endarterectomy performed through the transected aorta before anastomosis of the aortic prosthesis is presented. The surgical course and early follow-up results of the first 44 consecutive patients treated by this technique are reported. Twenty-three patients (25%) had symptomatic coronary artery disease, 36 patients (82%) had arterial hypertension, and 28 patients (64%) had elevated serum creatinine levels (mean 2.10 mg/dl). Primary indications for operation related to aortic disease in 39 patients (89%) and to poorly controlled hypertension in five patients (11%). Seventy-five renal arteries were revascularized; 11% of these arteries were occluded. Revascularizations were bilateral in 27 patients (61%), involved a solitary kidney in three patients (6%), and were unilateral in 14 patients (32%). Aortobifemoral bypass grafting was performed in 16 patients (36%), aortoiliac bypass was performed in 15 patients (34%), and infrarenal aortic replacement was performed in 11 patients (25%). Postoperative complications developed in 14 patients (32%). There were two postoperative deaths (4%). Nineteen patients had transient increases in serum creatinine levels greater than 0.5 mg/dl. Two patients required postoperative dialysis, neither related to failure of their renal revascularization. There were five late deaths, all as a result of myocardial infarction. Renal function improved in four patients and remained stable in 22 patients. Blood pressure was improved in 64% of patients previously hypertensive. These preliminary results indicate that renal endarterectomy through the transected aorta along with aortic reconstruction is a safe, efficient, and effective means of treating these complex lesions.

Adult↗
PubMed1989

Incorporation versus infection of retroperitoneal aortic grafts: MR imaging features.

The magnetic resonance (MR) imaging characteristics of normal aortic graft healing were compared with those of perigraft infection in 57 patients after aortic graft implantation. Thirty-three patients without postoperative complications underwent MR imaging in a 0.35-T unit 1 week after graft implantation, and 13 of those patients were reexamined 2-3 months after graft implantation. Twenty-four patients with clinically suspected perigraft infection underwent MR imaging 6 weeks to 18 years after graft implantation. Early normal postoperative changes were characterized by a perigraft collar of low to medium signal intensity on T1-weighted images and of high intensity on T2-weighted images in all 33 cases, consistent with perigraft fluid collection. In 10 of 13 patients reexamined 2-3 months postoperatively, the MR images demonstrated a collar of tissue consistent with perigraft fibrosis. In cases of clinical suspicion of retroperitoneal graft infection, MR imaging showed eccentric fluid collections of low to medium signal intensity on T1-weighted images and high intensity on T2-weighted images at more than 3 months after surgery. The MR findings were diagnostic of retroperitoneal perigraft infection in 17 of 20 patients shown to be infected at surgery. Retroperitoneal infection was correctly excluded on the basis of MR findings in four patients. Thus, MR imaging is an accurate imaging method for the diagnosis of aortic graft infection. In the early postoperative phase, resolving perigraft fluid cannot be differentiated from perigraft infection.

Adult↗
PubMed1989

Particle size distribution of lipoproteins from human atherosclerotic plaque: a preliminary report.

It is commonly believed that low-density lipoproteins (LDLs) carry cholesterol into the artery wall. In addition, some epidemiologic studies have suggested that triglyceride-rich lipoproteins, such as very-low-density lipoproteins (VLDLs), may be much less important than LDLs in atherogenesis. To determine if VLDLs or their metabolic remnants could have a direct role in the formation of atherosclerotic plaque, we examined lipoproteins isolated from endarterectomy specimens. Atherosclerotic plaque was obtained from eight subjects who underwent aortoiliac endarterectomy (4), aortic aneurysm repair (2), or visceral/renal endarterectomy (2). Plaques were washed extensively, minced, and incubated with a buffered saline solution. Lipoproteins were recovered from this solution via a selected-immunoaffinity column by means of a polyclonal antibody to human LDL (apolipoprotein B-100). Particle sizing from electron photomicrographs of negatively stained specimens indicated that 8% of the lipoprotein particles were the size of plasma VLDL (350 to 800 nm). Thirty-six percent were the size of plasma VLDL remnant particles (250 to 350 nm), and 56% were consistent in size with plasma LDL (175 to 250 nm). We conclude that VLDL- and VLDL remnant-sized particles appear to comprise a significant percentage of the lipoproteins found in human atherosclerotic plaque and could have a direct role in the atherosclerotic process.

Aged↗
PubMed1988

Aortorenal arterial autografts: the last two decades.

Arterial autografts were introduced nearly a quarter century ago at the University of California, San Francisco and have proven their value for replacement in many demanding arterial problems. Renal artery fibrodysplasia is one of the more common lesions treated with arterial autograft. Arterial autografts that ideally match the renal artery and its branches are procured from the patient's own internal iliac artery. Either straight or branched configuration are available depending on the replacement requirements. In-situ aortorenal autografts are employed for lesions of the main renal artery or primary branches. Ex vivo repair involves temporary nephrectomy, pulsatile hypothermic perfusion and precise micro-vascular repair with unrestricted exposure, illumination, and an unhurried pace with no threat of renal ischemic insult. Autografts are attached proximally to the side of the aorta and distally to the disease-free end of the renal artery or a branch. The technique of arterial substitution for ex vivo repairs are identical except for the additional reanastomosis or reattachment of the renal vein. The arterial autograft exhibits the compliance characteristics which resemble a normal artery, maturation when used in the growing child, and durability essential for the long life span of this treated population. When the objective of a renal artery reconstruction is a normal renal arterial system, then the internal iliac artery autograft is the only choice.

Adult↗
PubMed1988

Does anesthetic technique make a difference? Augmentation of systolic blood pressure during carotid endarterectomy: effects of phenylephrine versus light anesthesia and of isoflurane versus halothane on the incidence of myocardial ischemia.

Whether anesthetic technique affected the incidence of myocardial ischemia in 60 patients undergoing carotid endarterectomy was investigated. The patients were randomly assigned to receive halothane or isoflurane (with nitrous oxide) either at a low concentration alone or at a higher concentration with phenylephrine added to support blood pressure. Blood pressure was maintained within 20% of each patient's average ward systolic pressure. Seven leads of electrocardiograms (ECG) and echocardiograms were analyzed for segmental wall motion. The echocardiograms were analyzed using standard formulae for end-systolic meridional wall stress (SWS) and rate-corrected velocity of fiber shortening (Vcfc). Because of the nature of these calculations, only echocardiograms with normal regional wall motion could be accurately analyzed. The patients had postoperative ECG and creatinine phosphokinase (CPK) isoenzyme determinations and regularly scheduled clinical examinations to detect perioperative myocardial infarction and neurologic deficits. Although blood pressures were similar, the patients who received a higher concentration of anesthetic plus phenylephrine had a higher wall stress, regardless of the choice of anesthetic agent. All four techniques allowed provision of the same stump pressures (the marker surgeons used for adequacy of collateral carotid flow). No difference could be found in wall stress or incidence of myocardial ischemia between isoflurane and halothane. The patients who received phenylephrine had a threefold greater incidence of myocardial ischemia than did the patients who had light anesthesia to maintain similar systolic blood pressures and stump pressures. The groups were demographically and hemodynamically similar; in particular, the heart rates were not different.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗