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Biomedical subjects

K Ouriel

Publications and source records attributed to K Ouriel.

At least 127 records · Page 7Linked to original sources
PubMed1991

The synthetic axillofemoral graft for hemodialysis access.

Patients who have exhausted all options for conventional dialysis access due to lack of available vessels may be candidates for placement of a synthetic axillofemoral vascular graft. The axillofemoral access is surgically constructed under general anesthesia. The synthetic graft is anastomosed, end to side, to the axillary artery, proximally, and distally to the common femoral vein. Surgical complications have been negligible and intravascular blood flow rates support efficient dialysis. A review of two cases demonstrates the positive outcomes and acceptability of this nonconventional approach for blood access in hemodialysis patients.

Arteriovenous Shunt, Surgical↗
PubMed1990

Fate of the exposed saphenous vein graft.

Patients with functioning vein grafts may present with wound problems resulting in exposure of the graft. We reviewed the courses of 16 patients presenting with this problem to determine the causative factors and the most appropriate management of this therapeutic dilemma. Diabetes mellitus (11 of 16, 68.7%) and wound infection (12 of 16, 75%) were frequent pre-existing conditions associated with exposed venous grafts. All patients with exposed vein grafts were initially treated conservatively with regular application of moist sterile dressings, followed by split-thickness skin graft coverage of the wounds when clean. The wounds healed in 7 patients, whereas 9 patients developed complications of hemorrhage (7 patients) and graft thrombosis (2 patients). The outcome of therapy was highly dependent on the type of organism originally cultured from the wounds. The incidence of vein graft disruption was lowest when the wounds were sterile (25%) or when gram-positive bacteria grew (25%). Gram-negative infection uniformly resulted in disruption of the exposed venous graft. When a new graft was placed, the secondary graft became reinfected in all patients with gram-negative primary graft infection. There were no instances of secondary graft reinfection when gram-negative bacteria were not present. These data suggest that the outcome of patients presenting with exposed vein grafts is highly dependent on the bacterial flora of the process. Vein graft disruption is frequent in patients with gram-negative infection, suggesting that these patients should be treated with distant graft ligation and extra-anatomic bypass. By contrast, patients without gram-negative infection may be successfully managed with local wound care.

Adult↗
PubMed1990

Differential effects of a gram-negative and a gram-positive infection on autogenous and prosthetic grafts.

A canine model was developed to study the differential response of a gram-negative and a gram-positive bacterial infection on autogenous and prosthetic grafts. After replacing segments of the femoral arteries of 15 dogs with autogenous vein in one groin and polytetrafluoroethylene in the contralateral groin, 10(8) colony-forming units of nonmucin-producing Staphylococcus epidermidis (five dogs), Pseudomonas aeruginosa (five dogs), or sterile saline solution (five dogs) were directly inoculated onto the grafts. The grafts were examined 7 to 10 days after implantation. None of the control dogs exhibited inflammatory signs, and no grafts or anastomoses disrupted. S. epidermidis was unrecoverable from either graft material in any of the animals, although histologic evaluation confirmed neutrophils and bacteria in four of five animals in the vein and polytetrafluoroethylene groups. No dog inoculated with S. epidermidis had graft or anastomotic disruption. By contrast, P. aeruginosa was recovered from both types of grafts in all inoculated animals. Neutrophils, bacteria, and microabscesses were observed in all of these animals. In addition, three of five polytetrafluoroethylene grafts and all five vein grafts disrupted either at the anastomoses or in the body of the vein graft. Therefore S. epidermidis is a less virulent organism that may persist in graft walls despite negative cultures, whereas P. aeruginosa is a highly virulent organism that can disrupt native artery, vein grafts, and anastomoses. The graft material appears to be less important than the bacteria in determining the outcome of infection.

Animals↗
PubMed1990

Factors determining survival after ruptured aortic aneurysm: the hospital, the surgeon, and the patient.

The 10-year experience of a single community was reviewed and a multivariate analysis was performed to determine the relative importance of clinical and environmental factors in mortality after ruptured abdominal aortic aneurysm resection. Ruptured aneurysms were repaired in 243 patients in six area hospitals (one university, five community) by 25 surgeons (16 vascular, 9 general). Overall, 30-day mortality was 55% (133/243). Although the mortality by hospital ranged from 44% to 68%, these differences were not statistically significant. However, significant variations occurred in the mortality rates of individual surgeons, ranging from 44% to 73%. The mortality rate for the vascular surgeons was less than that of the general surgeons, 51% versus 69% (p less than 0.05). Clinical factors were evaluated, and the most significant parameters were systolic blood pressure, presence of chronic obstructive lung disease, and history of chronic renal insufficiency. These results support the implication that the degree of specialization of the surgeon and the preexisting health of the patient are the most important determinants of survival after ruptured abdominal aortic aneurysm. The size and sophistication of the hospital appear to be less influential factors.

Aged↗
PubMed1990

Comparison of infrainguinal graft surveillance techniques.

One hundred seventy-seven patients with infrainguinal bypass grafts were followed by use of standard graft surveillance techniques to learn more about the natural history of hemodynamic abnormalities in the patient with no symptoms. A decrease in the ankle/brachial pressure ratio of 10% or more was considered an abnormal evaluation. Results of the duplex scan were interpreted as abnormal when the peak systolic flow velocity was greater than 120 cm/sec or less than 40 cm/sec. There were 18 graft thromboses (10%) during the period of observation, and nine of these grafts were successfully revised or replaced. Recurrent symptoms prompted graft revision in 20 additional patients, and 18 of these reoperations were successful. Twenty-nine of the 38 reoperations occurred within the first 18 months of the study. The primary cumulative patency rate was 86% at 1 year and 66% at 5 years. The secondary cumulative patency rate was 91% at 1 year and 80% at 5 years. Sudden graft occlusion occurred in five patients after a normal ankle/brachial index. Most of 90 patients with abnormal ankle/brachial indexes reverted to normal at the next visit. Nineteen of the 26 that did not, had significant graft problems, but only eight patients had operable conditions, and five of the eight already had occluded grafts. No patient with a normal ankle/brachial index and duplex scan results had graft occlusion before their next surveillance visit. If the duplex scan outcome was abnormal but the ankle/branchial index normal the incidence of sudden graft occlusion was 4%. In contrast, if the duplex scan outcome was abnormal and the ankle/brachial index is reduced, then the risk of graft occlusion is 66%.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Vessel Prosthesis↗
PubMed1989

Reexploration for thrombosis in carotid endarterectomy.

We reviewed the records of patients undergoing carotid endarterectomy and manifesting either postoperative stroke or thrombosis by oculopneumoplethysmography (OPG-Gee) to analyze the etiology of stroke and to determine the indications for reexploration. Of 900 consecutive elective endarterectomies performed during an 8-year period, 41 patients experienced a perioperative stroke, carotid thrombosis, or both. These patients were subdivided into three groups: group 1, 22 patients with perioperative stroke and carotid thrombosis; group 2, six patients with carotid thrombosis but without symptoms; and group 3, 13 patients with postoperative stroke but no thrombosis. In group 1, 17 patients were reexplored (group 1a), and five were observed without reexploration (group 1b). In group 2, three of the patients were reexplored (group 2a), and the remaining three were observed (group 2b). None of the group 3 patients were reexplored. In group 1a, four (23%) patients awoke from anesthesia with neurological deficits, whereas in group 3, nine (69%) patients awoke with such deficits. Follow-up at 30 days revealed that 76% of group 1a patients demonstrated improvement in symptoms, whereas similar results were seen in only 20% of group 1b patients and 23% of group 3 patients. These trends were maintained throughout the follow-up period of 1-5 years. Those patients who were asymptomatic, group 2, with thrombosis were more likely to have been operated on for asymptomatic carotid stenosis. with thrombosis were more likely to have been operated on for asymptomatic carotid stenosis. Thrombosis was the most common cause of postoperative stroke (63%) in patients after carotid endarterectomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Results of supraceliac aortic clamping in the difficult elective resection of infrarenal abdominal aortic aneurysm.

We have used clamping of the aorta above the celiac axis (SC) in 30 of 431 elective resections of infrainguinal abdominal aortic aneurysms (AAA) during the past five years as an alternative to a difficult aortic cuff dissection. The results of SC clamping in these 30 patients are compared with the results of 379 routine aneurysm resections with infrarenal (IR) clamping and 22 additional aneurysm resections where the clamp was placed immediately above the renal arteries. These difficult cuff dissections occurred in 12 patients with inflammatory AAA, in 11 patients with juxtarenal AAA, and in seven patients with recurrent or noninfected false AAA of the proximal cuff. Patients with ruptured or suprarenal aneurysms and those undergoing combined operation for a visceral ischemic syndrome and an aneurysm were excluded from this study. Patients with SC clamping had similar operative mortality rates, comparable renal function, and frequency of cardiac events as patients with IR clamping. Blood loss was slightly higher in the SC group (p = 0.07) and serum aspartate amino transferase (AST) levels were three times higher than in the IR group; however, this was of no clinical significance. In contrast, those 22 patients whose aortas were clamped immediately above the renal arteries (AR) had higher perioperative mortality rates (2% IR, 3% SC vs 32% AR) and a higher incidence of kidney failure requiring dialysis (1% IR, 3% SC vs 23% AR). The mean values of serum creatinine and blood urea nitrogen were also significantly higher in the AR group when compared with both the IR and the SC groups (IR: 25 and 1.5 mg/dl, respectively; SC: 27 and 1.8 mg/dl; AR: 41 and 3.5 mg/dl). The single most important risk factor accounting for the differences between clamping above the celiac artery and clamping above the renal arteries was the presence of atherosclerotic debris in the nonaneurysmal, juxtarenal aortic segment. Clamping the aorta with juxtarenal atherosclerosis caused either atheroembolization to kidneys, legs, and intestine or injury to the aorta, renal arteries, or both; it was the cause of morbidity in all five cases of kidney failure requiring dialysis and accounted for all seven of the deaths in the AR group. SC clamping does not add risk to the patient undergoing resection of an infrarenal AAA and is the preferred method of achieving proximal control of the infrarenal aorta when a a hazardous cuff dissection is likely.(ABSTRACT TRUNCATED AT 400 WORDS)

Aorta, Abdominal↗
PubMed1988

Detection of occult colonic ischemia during aortic procedures: use of an intraoperative photoplethysmographic technique.

A photoplethysmographic technique was used in 30 consecutive patients who had abdominal aortic reconstruction to assess colonic viability intraoperatively. A sterile pulse oximeter probe was used to measure arterial pulsatility and transcolonic oxygen saturation (TCOS) in the proximal, midportion, and distal sigmoid colon before and after the reconstruction. No attempt at inferior mesenteric revascularization was made, irrespective of the photoplethysmographic results. The status of the colon was assessed between the third and sixth postoperative day by a colonoscopist unaware of the intraoperative data. Before the reconstructive procedure photoplethysmography displayed pulsatile flow in all patients with a mean TCOS of 95% +/- 0.4%. After reconstruction, 28 patients (93%) demonstrated unchanged pulsatility with mean TCOS of 94% +/- 0.4%. Despite ligation of a patent inferior mesenteric artery in 10 of these patients, all 28 had normal colonoscopic examinations. By contrast, two patients (6.7%) had a loss of photoplethysmographic pulsatility with unmeasurable TCOS. Both of these patients had ligation of an initially patent inferior mesenteric artery and demonstrated evidence of ischemic mucosal changes at colonoscopy. Intraoperative colonic photoplethysmography represents an easily performed, accurate method for predicting colonic viability. A loss of pulsatility suggests inadequate postreconstructive colonic perfusion and mandates revascularization of the inferior mesenteric artery.

Aged↗
PubMed1988

Anomalous carotid-basilar anastomoses in cerebrovascular surgery.

Primitive embryonic anastomotic vessels between the internal carotid and basilar arterial systems occasionally persist into adult life. We encountered six such patients in a series of 765 carotid endarterectomies (0.8%). These arteries are named for the cranial nerves with which they run. The most commonly found vessel is the trigeminal artery, followed by the hypoglossal and proatlantal intersegmental arteries. The primitive otic artery is the rarest of the four anomalous vessels. These vessels are usually large and are associated with hypoplasia or aplasia of the normal intracranial anastomotic channels. Cerebral ischemia is common during temporary intraoperative carotid occlusion and was encountered in two of three patients who had intraoperative electroencephalographic monitoring. Thus cerebral ischemia should be anticipated during carotid cross-clamping and cerebral protective measures should be instituted when persistent primitive cranial vessels are encountered.

Basilar Artery↗
PubMed1988

Observations on cerebral computed tomography in patients having carotid endarterectomy.

A review was undertaken of all patients seen in our institution between January 1978 and March 1987 in whom a cerebral CT scan was obtained in association with elective carotid endarterectomy. Three hundred fifty-nine such patients were identified. In a subgroup of 89 patients who were neurologically normal after carotid endarterectomy, scans were performed at least 48 hours after surgery to quantitate the incidence of silent postoperative infarction. These scans were interpreted by one neuroradiologist. Preoperative cerebral CT scans showed ipsilateral infarction in 146 of 359 patients (40.6%). Ipsilateral infarction was most common in patients with stroke (76%) but was also seen in 32.8% of patients with transient ischemic attacks, in 9 of 40 patients (22.5%) with nonhemispheric symptoms, and in 9 of 45 patients (20%) with asymptomatic hemodynamically significant carotid stenosis. The postoperative stroke rate was not significantly increased by the presence of infarct on preoperative cerebral CT scan (2.6% vs 1.9%). New infarcts were seen on cerebral CT scanning after carotid endarterectomy in 2 of 89 patients with no detectable neurologic abnormality (2.3%). This study demonstrates a high frequency of ipsilateral infarction in patients having elective carotid endarterectomy, even in those patients with clinical symptom complexes thought by many physicians to be relatively benign (i.e., transient cerebral ischemia, nonhemispheric ischemia, and asymptomatic carotid stenoses).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

Limb-threatening ischemia in the medically compromised patient: amputation or revascularization?

The clinical courses of 362 patients with threatened limbs, seen over a 25-year period, were reviewed. Below-knee amputation was elected in 158 patients and infrainguinal revascularization in 204 patients. Patients were excluded from the study if amputation was chosen on the basis of arteriographic findings, diffuse infection, or extensive tissue loss. In an effort to compare the two treatment modalities in a minimally biased fashion, patients were stratified into three classes on the basis of the Goldman Multifactorial Index of Cardiac Risk and the American Society of Anesthesiology classification. Within each class, patients treated with amputation and with bypass were comparable with respect to age, sex, severity of ischemia, and anesthetic technique. Patients who underwent revascularization had a lower perioperative mortality rate (p less than 0.05), a shorter length of hospital stay (p less than 0.05), and an increased long-term survival rate (p less than 0.05) than the medically matched subgroup of patients who underwent amputation. Patients in the revascularization group were more successful in regaining ambulatory abilities than patients in the amputation group (p less than 0.01). These differences were most significant as the degree of medical compromise increased. Although medically compromised patients have frequently been denied revascularization on the basis of presumed increases in surgical risk and decreased long-term survival, the data appear to suggest that it is precisely the patients of this group who appear to benefit the most from attempts at limb salvage.

Aged↗
PubMed1988

Traumatic fracture of the abdominal aorta. Rupture of a calcified abdominal aorta with minimal trauma.

We report the case of an elderly man whose infrarenal abdominal aorta ruptured when the patient fell getting out of bed. Unique features of this case are the lack of aneurysmal disease, the insignificant nature of the trauma, and the severe, rigid atherosclerotic plaque in the infrarenal aorta. Pathologic examination of the resected aorta demonstrated the point of rupture to be at the junction of atherosclerotic plaque and normal aorta, suggesting that atherosclerosis is a predisposing factor in traumatic rupture of the abdominal aorta.

Abdominal Injuries↗
PubMed1987

Verapamil crystalloid cardioplegia: an experimental evaluation of dose-response relationships.

Calcium channel blockers have been advocated as agents which enhance myocardial protection during ischemia and reperfusion. Unfortunately, while cellular integrity is preserved, myocardial function is depressed as a result of the negative inotropic effects of these agents. In order to assess the efficacy of verapamil cardioplegia, 25 isolated perfused rabbit hearts were studied. A model of normothermic ischemic arrest was utilized, employing either verapamil-free crystalloid cardioplegia or cardioplegia containing verapamil in concentrations of 0.5, 1.0, or 5.0 mg/liter. All three verapamil-treated groups demonstrated increased postischemic left ventricular developed pressure and improved postischemic compliance when compared with the untreated group (P less than 0.05). However, myocardial function was significantly depressed at 15 min of reperfusion in the 1.0 and 5.0 mg/liter verapamil-treated groups when compared with the 0.5 ml/liter group (P less than 0.05). These data suggest that the addition of verapamil to crystalloid cardioplegia results in enhanced myocardial function while minimizing the early reperfusion depression associated with higher dose therapy.

Animals↗
PubMed1987

Acute renal artery occlusion: when is revascularization justified?

Acute renal artery occlusion is an infrequently encountered entity, with a paucity of literature on which to form clinical decisions. During a 20-year period 35 patients were treated for acute renal artery occlusion as a result of embolism (13 patients), thrombosis of a stenosed vessel (16 patients), or trauma (six patients). Patients were treated operatively in 16 cases and nonoperatively in 19 cases. In patients with embolic occlusion, embolectomy was successful in the relief of hypertension but was ineffective in the restoration of renal function. In patients with thrombotic occlusion, thrombectomy and aortorenal bypass were successful in both the reduction of blood pressure and the retrieval of renal function. In this group, salvage was dependent on the presence of a reconstituted distal renal artery, irrespective of the operative delay. In patients with traumatic renal artery occlusion, return of renal function did not occur, despite reperfusion as early as 6 hours after injury. These data suggest that the period in which function of embolized or traumatized kidneys may be preserved has usually passed by the time the diagnosis of renal artery occlusion has been made. By contrast, operative therapy of thrombotic occlusion frequently results in return of renal function, irrespective of the delay in treatment.

Adolescent↗
PubMed1987

High-risk aortic aneurysm repair with partial cardiopulmonary bypass.

Two patients with severe cardiac dysfunction and measured left ventricular ejection fractions of 18% and 20% underwent aneurysm repair with the use of femoral vein--femoral artery partial cardiopulmonary bypass. While the aorta was clamped, blood was withdrawn through the venous cannula, and oxygenated blood was delivered to the legs through the arterial cannula. This procedure allowed clamping and unclamping of the aorta to proceed without hemodynamic fluctuation. Intraoperatively, cardiac output, mean arterial pressure, pulmonary artery diastolic pressure, right atrial pressure, pulmonary capillary wedge pressure, and systemic vascular resistance were measured. Both patients recovered, which indicates that this technique may be safely undertaken in the severely compromised patient with cardiac disease.

Aged↗
PubMed1987

Clinical and technical factors influencing recurrent carotid stenosis and occlusion after endarterectomy.

Carotid endarterectomy was performed in 152 patients during a 27-month period. The first 82 patients had primary closure of the arteriotomy, whereas the subsequent 70 patients underwent closure with Dacron patch angioplasty. Duplex scanning was undertaken postoperatively in 102 of these patients with a mean follow-up period of 17 months. Perioperative thrombosis occurred in two patients (1.3%), late postoperative recurrent stenosis in 14 patients (13.7%), and late postoperative occlusion in three patients (2.9%). Of the various factors investigated for their correlation with late recurrent stenosis or occlusion, only three were significant: the female sex (recurrent stenosis in 29% vs. 8%, p less than 0.05), a small (less than 4 mm) internal carotid artery (37% vs. 12%, p less than 0.05), and failure to close the arteriotomy with a patch (29% vs. 6%, p less than 0.05). The development of recurrent carotid lesions appeared independent of smoking history, antiplatelet therapy, use of a shunt, or extent of carotid plaque. These data suggest that patients with small internal carotid arteries, specifically female patients, are at greater risk for recurrent carotid stenosis. Patch angioplasty may decrease this risk and should be considered in these patients.

Arterial Occlusive Diseases↗