Recurrent carotid artery stenosis following endarterectomy.

Spectral analysis was used to examine 257 carotid arteries in 227 patients who had undergone carotid endarterectomy at 1, 3, 6, and 12 months after surgery and annually thereafter. Routine intraoperative completion angiography ensured that the operations were technically satisfactory. Postoperative restenoses were identified in 38 patients (15%).

Doppler power frequency spectrum analysis in the diagnosis of carotid artery disease.

Power Frequency Spectral Analysis (PFSA) which evaluates the power of the frequency components at a selected interval, was applied in this preliminary study using a 5MHz Doppler continuous wave flow velocity meter and a modified Edwards Spectraview 500 analyzer. PFSA was used to study the common, internal and external carotid arteries of ten young adult control subjects and 31 patients with angiographically documented carotid bifurcation lesions. Two useful indices are described: (1) the frequency band width at 50% of maximum power (f50%) and (2) the highest frequency recorded (fmax).

[Myelinization of the optic nerve in the albino mouse (the Agnes Bluhm Jena-Halle strain)].

Knowledge of normal differentiations is indispensable for interpreting developmental disturbances in animal experiments. Accordingly, the investigations described in the present paper were aimed at explaining the process of myelinization of the optic nerve in the domestic mouse breed Agnes Bluhm Jena-Halle. First signs of myelin sheath formation can be seen on the sixth and seventh day post partum.

Selective streptokinase infusion: clinical and laboratory correlates.

Selective intra-arterial infusions of streptokinase (SK) were made in 50 arteries of 45 patients with a variety of acute thromboembolic conditions. The most common regimen was 5,000 units of SK/hour for 24 to 48 hours with a simultaneous heparin infusion of 250 to 500 units/hour. Significant lysis occurred in 80% of cases, with 74% of the patients benefiting clinically.

Natural history of asymptomatic ulcerative plaques of the carotid bifurcation.

In 79 patients with 91 asymptomatic ulcerating lesions of the carotid bifurcation who were followed an average of 54 months, there were two strokes, one of which was preceded by a warning transient ischemic attack. These data suggest that asymptomatic type A and type B carotid ulcerating lesions do not carry a significant early risk of stroke and do not warrant prophylactic carotid endarterectomy. However, the effect of antiplatelet drugs and anticoagulation in enhancing the development of subintimal hemorrhagic lesions remains uncertain.

Life expectancy and late stroke following carotid endarterectomy.

A review of the UCSD experience with 456 consecutive carotid endarterectomy procedures confirms the acceptably low operative mortality and morbidity associated with this operation. Immediate complications were not different when routine or selective shunting was performed, but the patients with a low internal carotid artery back pressure had higher operative complication rates. The coexistence of atherosclerosis in other parts of the body severe-enough to warrant surgery for them was not associated with either higher early or late carotid surgery complication rates.

Is carotid endarterectomy beneficial in prevention of recurrent stroke?

Of 456 consecutive carotid endarterectomies performed at the University of California, San Diego, 127 were in patients who had sustained a previous completed stroke and had recovered with minimal but permanent neurologic deficits (PNDs). Operative mortality for the entire series was 0.9%, but it was 3.

Should aortography be used routinely in the elective management of abdominal aortic aneurysm?

Until recently aortography was performed routinely for elective abdominal aortic aneurysm at our institution. A death resulting from this procedure prompted us to evaluate this policy by a retrospective study of 105 elective aneurysm patients. These studies identified 21 renal artery stenoses, 2 renal artery aneurysms, 2 cases of multiple renal arteries, 8 celiac stenoses, 6 superior mesenteric artery stenoses or occlusions, and a number of peripheral occlusive processes and associated iliac aneurysms.

Current status of noninvasive tests in the diagnosis of peripheral arterial disease.

In this review of the current status of the vascular laboratory, the major emphasis has been upon those tests that have become well-established and documented, including resting pressure, pulse volume measurements, velocity studies, and three stress measurements--exercise ankle pressure, postocclusive reactive hyperemia, and the toe pulse reappearance time. Additional technology that may have application to peripheral arterial disease includes photoplethysmography, transcutaneous oxygen tension, laser-Doppler velocimetry, fluorescein angiography, infrared thermography, and transcutaneous electromagnetic flowmetry. These techniques, which are currently in development and experimental trial, were not discussed but are likely to provide significant additional information.

The current status of carotid artery surgery.

The natural history of extracranial cerebrovascular disease and available alternatives in its treatment are reviewed. An evaluation of the evidence suggests that carotid endarterectomy is the treatment of choice in patients with transient ischemic deficits, provided that an anatomically appropriate lesion can be identified. These patients have a 25-38% chance of stroke if untreated, which can be reduced to 5-10% by carotid endarterectomy.

Transcutaneous PO2 measurements in health and peripheral arterial occlusive disease.

Transcutaneous oxygen tensions (tcPO2) of the lower extremity were investigated in 24 control subjects and in 69 patients with various degrees of peripheral arterial occlusive disease. With a modified Clark-type oxygen electrode, tcPO2 was monitored from the right subclavicular region (position 1), upper calf (position 2), and dorsum of the foot (position 3). The tcPO2 was significantly lower in patients when compared to control subjects.

Digital ischemia: angiographic differentiation of embolism from primary arterial disease.

Embolic disease is often overlooked as a cause of digital ischemia. Unilateral symptoms, in particular, should suggest the possibility of emboli arising from the subclavian or more distal upper extremity vessels. Emboli may originate in the subclavian artery as the result of atherosclerosis at its origin or arterial injury secondary to thoracic outlet compression.

Valve competence following experimental venous valve autotransplantation.

In canine experiments, venous patency and valvular competence were evaluated following transposition of a valve-containing vein segment, with an without a distal arteriovenous (AV) fistula. The effects of distal fistula size on valvular function were also examined. Autogenous valve-containing venous segment grafts were placed in the femoral position.

The effect of sensing site on the limb segmental blood pressure determination.

The effect of the sensing site on upper-thigh blood pressure readings was studied. We used a multisensing mercury strain gauge (MSG) plethysmographic method and Doppler ultrasound to monitor the upper-thigh blood pressure from the posterior tibial artery and compared the results with those from the popliteal artery. Upper-thigh pressures were measured in 30 limbs of 15 normal subjects and in 60 limbs of 35 patients with multilevel peripheral arterial occlusive disease.

Acute physiologic effects of arteriovenous anastomosis and fistula in revascularizing the ischemic canine hind limb.

In a severe, diffuse arterial occlusion model of canine hind-limb ischemia, both distal arteriovenous fistula (AVF) and arteriovenous end-to-side anastomosis (AVA) were evaluated as potential methods of revascularization. AVA reversed or minimized both hemodynamic and metabolic indices of ischemia; AVF did not. After AVA segmental blood pressures at the thigh returned to normal, and those at the calf returned to 0.

Employee attitude surveys: perception vs. reality.

In order to correctly interpret employee perceptions, analysts must understand the organization's past, present, and future goals and policies, its performance and success, and its place in the business environment.

Thigh pressure artifacts with noninvasive techniques in an experimental model.

In an experimental canine model of isolated and tandem arterial stenoses, noninvasive thigh and calf pressure measurements were evaluated against direct intra-arterial pressures. Under control circumstances, proximal iliac arterial stenosis, and high superficial femoral artery stenosis, the noninvasive measurements were highly accurate. However, when stenoses were created distal to the high pressure cuff, a significant error in the thigh pressure measurement was observed, with an underestimation of thigh pressure and subsequent false implication of a proximal lesion.

Toe pulse reappearance time in prediction of aortofemoral bypass success.

The noninvasive vascular laboratory has a great potential to influence patient care if it can offer predictive information, which significantly adds to the clinical and angiographic assessment. To evaluate such preoperative data, 80 patients (143 symptomatic limbs) who underwent aortofemoral bypass were re-evaluated one to seven years following surgery. Preoperative vascular laboratory data (segmental pressure profile, quantitative Doppler velocity indices, postocclusive reactive hyperemia and toe pulse reappearance time [TPRT], following a four-minute cuff occlusion), angiography and clinical status were compared with the postoperative symptomatic result.

Prognosis of asymptomatic ulcerating carotid lesions.

To determine the proper approach to asymptomatic carotid bifurcation ulcerated plaque (UP), 79 patients with 91 asymptomatic UPs were identified angiographically, and a 96% follow-up was obtained with a mean duration of three years. The cumulative stroke rate by life-table analysis was 1% at seven years. Sixty-three UPs in 55 patients were classified as small, and of these patients, transient ischemic attacks (TIAs) that were appropriate to the lesion developed in three and stroke in one (7% cumulative symptom rate).

Ultrasonic imaging of the carotid arterial system.

The ability of a B-mode, real-time, high frequency ultrasonic imager to diagnose carotid arterial disease was evaluated in 81 carotid arteries. The imager was relatively sensitive in detecting the presence of significant stenosis but was relatively insensitive in its ability to quantitate the degree of stenosis. The imager was unable to detect the presence of ulcerations.