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Biomedical subjects

T W Rooke

Publications and source records attributed to T W Rooke.

At least 37 records · Page 2Linked to original sources
PubMed1992

Reconstruction of large veins for nonmalignant venous occlusive disease.

To evaluate the effectiveness of venous grafting, we reviewed the management and clinical course of 28 patients (21 males and seven females) who underwent 29 reconstructions of large veins for benign disease. There were 12 patients with superior vena cava (SVC) syndrome, two with subclavian vein thrombosis, and 15 with occlusion of the inferior vena cava (IVC) or iliac veins. One of these patients underwent both IVC and SVC reconstructions. Reconstruction of the SVC was performed with spiral saphenous vein graft (SSVG) in nine patients and expanded polytetrafluoroethylene (ePTFE) in three. All seven straight SSVGs had documented patency at a median of 7 months (2 weeks to 5 years) after reconstruction. Six patients had complete relief of symptoms. Two patients with bifurcated SSVG had early occlusion of one graft limb. Two of the three ePTFE grafts needed early thrombectomy. One graft reoccluded at 6 months and two were patent at 2 and 5 years. The two subclavian vein reconstructions with axillary-jugular ePTFE grafts with an arteriovenous fistula had documented early patency. Both patients had rapid resolution of symptoms. The IVC or iliac vein was reconstructed with ePTFE graft in 11 patients, SSVG in three, and Dacron in one. A femorofemoral arteriovenous fistula was added in eight patients with ePTFE grafts. Seven of the 11 ePTFE grafts had documented patency at the last follow-up (median 9 months; range 2 weeks to 5 years). None of the three SSVGs had documented long-term patency. The one Dacron cavoatrial graft occluded at 3 years. A straight SSVG continues to be our first choice for SVC replacement. Short, large-diameter ePTFE grafts perform the best in the abdomen. Femorocaval or long iliocaval grafts need an arteriovenous fistula to maintain patency. Long-term patency after closure of the fistula is still unknown. Femorocaval grafts with poor venous inflow have limited chance of success. Failed or failing grafts may be salvaged by early thrombectomy. Venous reconstruction to treat selected patients with symptoms with large vein occlusion continues to be a viable option.

Adult↗
PubMed1992

Predictive value of transcutaneous oxygen pressure and amputation success by use of supine and elevation measurements.

The purpose of this study was to determine if transcutaneous oxygen pressure (tcPO2) measurements can be used to predict amputation site healing in lower limbs with arterial occlusive disease. We measured tcPO2 (supine and with limb elevation) in 90 limbs before amputation and reviewed their subsequent clinical course. Of these, 52 (57%) successfully healed, 21 (23%) failed, and 17 (18%) exhibited delayed healing. Limbs with delayed healing or failure had significantly lower tcPO2 values than values of those that healed. A tcPO2 greater than or equal to 40 torr was associated with primary or delayed healing in 51 of 52 limbs (98%), and a tcPO2 value of less than 20 torr was universally associated with failure. For patients with a tcPO2 between 20 and 40 torr, tcPO2 measurements obtained during limb elevation improved the predictability of outcome. We conclude that supine tcPO2 measurements can help predict amputation site healing, and that tcPO2 measurement during limb elevation improves predictability in limbs with borderline supine tcPO2 values.

Adult↗
PubMed1991

Evaluation and management of patients with both peripheral vascular and coronary artery disease.

The prevalence of serious angiographic coronary artery disease ranges from 37% to 78% in patients undergoing operation for peripheral vascular disease. Clinical studies have demonstrated that cardiac outcome after peripheral vascular surgery is not adequately predicted by the standard criteria of history, physical findings and rest electrocardiogram. An adequate exercise work load, left ventricular function and thallium redistribution have proved important in perioperative risk stratification. The choice of a perioperative functional cardiac test depends on patient-related factors and the nature of the peripheral vascular operation. Although procedures involving aortic cross-clamping exert a greater hemodynamic stress than do carotid endarterectomy and femoral popliteal surgery, late cardiac morbidity and mortality are significant in all patients with atherosclerotic disease. The decision to proceed with preoperative coronary angiography and myocardial revascularization should be based primarily on indications independent of the peripheral vascular procedure. However, peripheral vascular surgery may influence the timing of myocardial revascularization. Patients with high risk or unstable coronary artery disease may benefit from preoperative coronary revascularization, although this hypothesis remains unproved. In all patients, careful monitoring during and after operation is essential. All patients with peripheral vascular disease should be considered to be at lifelong risk for fatal and nonfatal cardiac events and should undergo appropriate clinical and laboratory evaluation and be treated accordingly.

Coronary Disease↗
PubMed1991

Klippel-Trenaunay syndrome: the risks and benefits of vascular interventions.

Our experience with Klippel-Trenaunay syndrome (KTS), a rare congenital malformation, has increased considerably in recent years and now includes 144 patients (65 male and 79 female patients). Hemangioma was present in 137 patients (95.1%), varicosity in 110 (76.4%), and hypertrophy of the soft tissues or bones in 134 (93.1%). In most patients (71.5%) the disease involved one lower extremity. Diagnostic workup included roentgenogram to document limb length discrepancy, noninvasive arterial and venous evaluation, contrast venography, and nuclear magnetic resonance imaging. Most patients did well without treatment or with elastic compression only. Surgical treatment for the vascular malformation in KTS is rarely needed and it continues to be controversial. To evaluate the risks and benefits of vascular interventions, we examined in detail the clinical histories of nine patients who in the last decade underwent operation for a vascular malformation of the lower extremity. In seven patients we removed varicose veins or resected hemangioma of the lower extremity. Although none was cured, all five who underwent resection of varicose veins and one of the two patients who underwent resection of a hemangioma improved. Two additional patients, however, who underwent resection of varicose veins in another institution had worsening of the symptoms. In one patient we performed deep venous reconstruction for atresia of the superficial femoral vein, using the contralateral saphenous vein. Such operation in KTS has not been reported previously. The patient has a patent graft with a competent valve and clinical improvement 6 months after the operation. Although patients with severe chronic venous insufficiency, disturbing cosmetic appearance, or complications of hemangioma may benefit from surgical treatment, detailed preoperative imaging of the extremity and pelvis with magnetic resonance imaging and contrast venography is needed to decrease complications. Rarely, reconstruction for atresia or hypoplasia of the deep veins may be needed.

Adolescent↗
PubMed1990

The influence of age, sex, smoking, and diabetes on lower limb transcutaneous oxygen tension in patients with arterial occlusive disease.

A retrospective study involving 129 patients (256 limbs) with unilateral or bilateral arterial occlusive disease was performed to assess the effects of age, sex, smoking, and diabetes on lower limb transcutaneous oxygen tension (TcPo2) measurements of were made according to a standard protocol, and the severity of lower limb arterial occlusive disease was estimated using the clinical signs and symptoms of disease or the ankle/brachial blood pressure index. The results demonstrated that age, sex, and smoking had no major effects on limb TcPo2 or disease severity; however, both limb TcPo2 and clinical disease severity were adversely affected by diabetes. When limbs with similar occlusive disease severity were compared, TcPo2 remained consistently lower in diabetic than in nondiabetic patients. We conclude that diabetes causes a reduction in limb TcPo2 beyond that which can be accounted for by large-vessel arterial occlusive disease alone.

Age Factors↗
PubMed1989

Variability and reproducibility of transcutaneous oxygen tension measurements in the assessment of peripheral vascular disease.

Transcutaneous oxygen tension (TcPO2) was measured according to a standard protocol in 43 limbs from 23 subjects, by use of oxygen-sensing electrodes attached to the chest (at a single site) or dorsum of the foot (at proximal and distal sites, located 1-2 cm apart). With the subjects supine, distal foot TcPO2 differed from proximal by an average of +/- 7.4 mmHg, and in 80% of all limbs the differences were between -6 mmHg and +15 mmHg. The two TcPO2's were subsequently combined to yield a single "average" value for each foot. TcPO2 measurements were repeated twenty-four to forty-eight hours later; in the supine position the change in "average" foot TcPO2 from the first to second measurement was +/- 6.9 mmHg, and in 80% of limbs the changes were between -11 mmHg and +9 mmHg. Similar reproducibility data were also obtained for ankle/brachial blood pressure indices (ABIs), chest TcPO2, and foot TcPO2 during three minutes of leg elevation at 30 degrees. The authors conclude that: (1) TcPO2 measurements from adjacent areas on the dorsum of the foot usually differ by 20-25% or less and (2) the short-term reproducibility of TcPO2 between studies is comparable to that for ABIs.

Arterial Occlusive Diseases↗
PubMed1988

Effect of intermittent venous occlusion on transcutaneous oxygen tension in lower limbs with severe arterial occlusive disease.

We evaluated the ability of intermittent venous occlusion to improve cutaneous circulation in patients with severe peripheral arterial occlusive disease. Fourteen patients with ischemic lower extremities had a pneumatic cuff placed around the thigh of an ischemic limb; intermittent inflation of this cuff produced a significant increase in the transcutaneous oxygen tension of the foot, suggesting that cutaneous blood flow had been improved.

Arterial Occlusive Diseases↗
PubMed1988

Effect of arterial revascularization on transcutaneous oxygen tension of the ischemic extremity.

In 20 patients (24 limbs) with peripheral occlusive arterial disease involving the lower extremities, foot and chest transcutaneous oxygen tension (tcPO2) and ankle and arm systolic blood pressures were measured, with the patient's legs horizontal and with them in an elevated position, before and after revascularization procedures. Eighteen of the procedures were unilateral and were performed to alleviate severe ischemia; the three bilateral procedures were done to relieve intermittent claudication. Regional perfusion index (RPI) was calculated for each foot (RPI = tcPO2 foot/tcPO2 chest) with the legs horizontal and with the legs elevated for 3 minutes (RPI3). The ankle/brachial index was calculated from ankle and arm systolic blood pressures. Limbs with severe ischemia had considerably decreased RPI and RPI3 before revascularization, whereas limbs affected by claudication had only a modest decrease in RPI but a pronounced decrease in RPI3. The tcPO2, RPI, and RPI3 increased substantially after revascularization.

Arm↗
PubMed1987

Percutaneous transluminal angioplasty in the lower extremities: a 5-year experience.

From January 1979 to March 1984, percutaneous transluminal angioplasty (PTA) was used to treat 148 limbs of 135 Mayo Clinic patients with occlusive arterial disease of the lower extremities. The procedure was technically successful in more than 95% of the attempts. The outcome was clinical improvement in 89 limbs and no improvement in 40 limbs; in 19 limbs, PTA was technically successful but the patient was dismissed from the hospital and lost to follow-up before the extent of improvement could be determined. Mean ankle/brachial pressure indices increased after PTA in those with clinical improvement but not in those without improvement. Clinical improvement was less likely to follow PTA in patients with advanced age, diabetes, severe initial symptoms, low ankle/brachial indices, or distal occlusive disease. In patients with improvement after PTA, the mean follow-up period was 33 months; during that time, failure (defined as recurrence of the original symptoms or the need for repeat PTA or operation) occurred at a rate of 6.4% per year. Serious complications occurred after three procedures (2.0%). We conclude that PTA is technically feasible and generally safe for many patients with occlusive arterial disease of the lower limbs.

Aged↗
PubMed1987

The influence of sympathetic nerves on transcutaneous oxygen tension in normal and ischemic lower extremities.

The authors evaluated the relationship between sympathetic nerve activity and transcutaneous oxygen tension (TcpO2) in normal and ischemic lower extremities. Dorsal foot TcpO2 was measured by using oxygen-sensing electrodes with surface temperatures of 42 degrees C and 45 degrees C; in theory, changes in sympathetic activity should affect vasomotor tone and TcpO2 in skin beneath an electrode at 42 degrees C (submaximal vasodilation), but not at 45 degrees C (maximal vasodilation). The vasodilation index (TcpO2 at 42 degrees C/TcpO2 at 45 degrees C) was created as an index of vasomotor tone (vasodilation index increases as tone decreases). In normal limbs (n = 24) averages for TcpO2 at 42 degrees C, TcpO2 at 45 degrees C, and vasodilation index were 30.3 mmHg, 62.1 mmHg, and 0.47, respectively. In subjects (n = 5) with quadriplegia and reduced sympathetic tone secondary to cervical cord trauma, TcpO2 at 42 degrees C and vasodilation index were increased (45.0 mmHg and 0.61); TcpO2 at 45 degrees C did not change. When normal subjects (n = 7) were chilled for twenty minutes with a cooling blanket at 5 degrees C (to increase sympathetic tone) average vasodilation index dropped from 0.50 to 0.29. Among ischemic limbs (n = 34) vasodilation index was highly variable (range: 0-0.77); in general, vasodilation index fell as the ischemia worsened. In a subset of patients with ischemic limbs, the vasodilation index increased after the limb was wrapped in a warm dressing (average vasodilation index = 0.25 without dressing, 0.37 with dressing). The authors conclude: TcpO2 can be used to assess the degree of vasomotor tone (and sympathetic activity) in skin; tone generally increases as ischemia worsens; and local warmth can improve cutaneous circulation in ischemic limbs.

Cold Temperature↗
PubMed1986

Heparin and the in-hospital management of deep venous thrombosis: cost considerations.

Numerous protocols for the treatment of deep venous thrombosis (DVT) with heparin have been recommended. In the past, physicians rarely considered costs in their decision to use a particular protocol; however, the recent introduction of the diagnosis-related groups (DRGs) and other cost-reduction measures has imposed financial limitations on the practice of medicine and surgery. To determine how the cost of treatment for DVT at the Mayo Clinic might be affected by the use of alternative heparin protocols, we conducted a two-stage study. In the first part, charts of 40 patients with uncomplicated DVT were analyzed retrospectively to determine an "average" Mayo Clinic heparin protocol for DVT. In the second part, this "average" protocol was compared with four other currently advocated protocols, and the cost of using each protocol at the Mayo Clinic was estimated. These protocols differed from the Mayo Clinic protocol with respect to method and route of heparin administration, frequency of monitoring anticoagulation, and duration of heparin treatment. This analysis revealed that the average charges resulting from treatment of DVT at the Mayo Clinic exceeded the corresponding DRG payment and that the cost of treatment varied substantially with the protocol used (a difference of more than $2,000 between two of the protocols analyzed). A review of the literature provided little evidence to suggest that the alternative protocols were not equally effective. Therefore, we concluded that measures such as shortening the duration of heparin therapy, administration of heparin by the subcutaneous route, and minimal monitoring of anticoagulation (in patients with a low risk of bleeding) can substantially reduce the cost of treating DVT and may be no less effective than other protocols for heparinization.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Contractions of the canine coronary artery in calcium-free solution.

Prostaglandin F2 alpha, but not norepinephrine, augments the maximal contractile response to potassium. To examine the mechanism underlying this augmentation, rings of canine coronary artery were studied isometrically in physiological salt solutions of various composition. The contractions evoked by prostaglandin F2 alpha were larger in high-potassium, calcium-free solution than in calcium-free solution. Similar results were obtained using canine saphenous vein and femoral artery. Isoproterenol, but not nimodipine, relaxed the contractions produced by prostaglandin F2 alpha in high-potassium, calcium-free solution. Unlike prostaglandin F2 alpha, norepinephrine failed to constrict rings in high-potassium, calcium-free solution. In calcium-free solution, prostaglandin F2 alpha-induced contractions increased with increasing potassium concentrations, but no enhancement occurred when lithium was substituted for potassium. Rings of coronary artery incubated with calcium-45 did not show changes in prostaglandin F2 alpha-induced calcium-45 efflux following changes in potassium concentration. These results suggest that potassium enhances coronary vascular smooth muscle contraction to prostaglandin F2 alpha, but not norepinephrine, independently of calcium entry.

Animals↗
PubMed1984

Pharmacology of bucindolol in isolated canine vascular smooth muscle.

To determine the effects of bucindolol on isolated vascular smooth muscle, rings of canine coronary and femoral arteries and saphenous veins were suspended for isometric tension recording in organ chambers filled with physiological salt solution. Bucindolol (3 X 10(-10) to 1 X 10(-7) M) had a comparable inhibitory effect on relaxations induced by isoproterenol in coronary arteries (which contain postjunctional beta-1 adrenoceptors) and saphenous veins (which contain postjunctional beta-2 adrenoceptors). Bucindolol (1 X 10(-7) M) had no effect on relaxations induced by sodium nitroprusside during contractions evoked by prostaglandin F2 alpha in either saphenous veins or coronary arteries. Bucindolol also had weak (relative to its beta adrenoceptor effect) alpha adrenoceptor-antagonistic activity that was greater for postjunctional alpha-1 than alpha-2 adrenoceptors. In all tissues tested, bucindolol in concentrations greater than 1 X 10(-6) M caused relaxations of responses induced by various nonadrenergic agonists. Propranolol (5 X 10(-6) M) did not alter the direct inhibitory effect that bucindolol had on contractions of coronary arteries or saphenous veins evoked by prostaglandin F2 alpha; this inhibitory effect of bucindolol was independent of the endothelium. In superfused saphenous vein strips, previously incubated with [3H]norepinephrine, bucindolol (3 X 10(-7) to 1 X 10(-5) M) increased the basal efflux of [3H]norepinephrine and its [3H] metabolites. Bucindolol at 1 X 10(-7) M inhibited prejunctional beta adrenoceptors without affecting prejunctional alpha adrenoceptors. These experiments indicate that bucindolol in decreasing orders of activity 1) has nonselective beta adrenoceptor-antagonistic properties, 2) has a selective alpha-1 adrenoceptor-inhibitory effect and 3) has a nonspecific direct relaxing action on vascular smooth muscle.

Adrenergic beta-Antagonists↗
PubMed1983

Relaxation of canine saphenous vein following brief transmural nerve stimulation.

The ability of electrical stimulation to cause relaxation in the canine saphenous vein was evaluated. Rings of vein were studied isometrically in organ chambers containing physiological salt solution. Prostaglandin F2 alpha produced stable contractions, during which brief periods of electrical stimulation caused further contraction. With cessation of the electrical stimulation, tension transiently decreased to a level below that observed prior to the stimulation (undershoot). This poststimulation undershoot was blocked by tetrodotoxin, phentolamine, ouabain, and potassium-free solution; it was not affected by atropine, cimetidine, indomethacin, ketanserin, methysergide, propranolol, pyrilamine, or removal of the endothelium. Undershoot did not occur following electrical stimulation during contractions evoked by norepinephrine. During superfusion with PGF2 alpha, a brief exposure to exogenous norepinephrine caused a transient contraction followed by a subsequent undershoot. These results suggest that 1) the interaction of norepinephrine with postjunctional alpha-adrenoceptors on vascular smooth muscle leads to an increase in the activity of Na+-K+-ATPase, and 2) increased activity of Na+-K+-ATPase is responsible for the poststimulation undershoot.

Animals↗
PubMed1983

Alpha-1 adrenoceptors and calcium in isolated canine coronary arteries.

Experiments were designed to define the postjunctional alpha adrenoceptor subtype(s) in large canine coronary arteries and to determine the dependency of contractions due to their activation upon the entry of extracellular calcium. Rings of left circumflex coronary artery were mounted at their optimal length for isometric tension recording in organ chambers filled with physiological salt solution. Phenylephrine and cirazoline were full agonists relative to norepinephrine. Methoxamine was a partial agonist relative to norepinephrine whereas clonidine, xylazine, B-HT 920 and B-HT 933 produced minimal contractions. Prazosin competitively inhibited the contractile response to phenylephrine (pA2 = 8.6), whereas rauwolscine caused a noncompetitive inhibition and was more than 100 times less potent than prazosin at inhibiting the response to phenylephrine. Similar results were obtained using norepinephrine (in the presence of propranolol) as the agonist. The calcium-entry blockers nimodipine, verapamil and diltiazem inhibited contractions caused by norepinephrine, phenylephrine and cirazoline. Removal of extracellular calcium abolished the response to cirazoline. These results suggest that in large canine coronary arteries: 1) only alpha-1 adrenoceptors are present postjunctionally and 2) responses due to alpha-1 adrenoceptor activation are dependent upon extracellular calcium.

Adrenergic alpha-Agonists↗