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Biomedical subjects

D P Link

Publications and source records attributed to D P Link.

At least 37 records · Page 2Linked to original sources
PubMed1982

Vasodilator response in the lower extremity induced by contrast medium. I Canine model.

The vasodilator response induced by injections of contrast medium was observed in 11 dogs by electromagnetic flow technique. The experiments were performed to further understand video dilution technique (VDT) measurements in patients with arterial obstructive disease. Responses were observed with regard to the contrast dose relationship, time to peak flow, and abnormal flow produced up to 4 ml caused increasing magnitude of peak flow. The time to peak flow was relatively constant for all doses. Mechanical constrictions depressed th peak flow magnitude but did not affect the time to peak. Emboli produced both depression of the flow magnitude and a delay in time to peak flow. The data suggest that the VDT vasodilatory response curves obtained in patients should correlate with the degree of obstructive disease and delay in the peak flow implies outflow disease.

Angiography↗
PubMed1982

Vasodilator response in the lower extremity induced by contrast medium. III. Before and after percutaneous transluminal angioplasty.

A standardized test series of contrast medium injections was performed in the iliac and femoral arteries to evaluate the immediate effect of percutaneous transluminal angioplasty. The vasodilator response recorded by video dilution technique was correlated to radiographic anatomy and symptomatology. Discrepancy between anatomic success and clinical relief of symptoms was found in 26 per cent of the dilatations. The severity of disease at the trifurcation was more marked in combination with femoral lesions than with corresponding iliac lesions. Rest pain was a common symptom with femoral lesions and rare with iliac lesions. Resting blood flow increased significantly after femoral dilatation but was unaffected by iliac dilatations. The video dilution technique provided an accurate staging of the severity of obstructive disease, and was an excellent predictor of subsequent symptomatic success or failure of percutaneous transluminal angioplasty.

Adult↗
PubMed1982

Vasodilator response in the lower extremity induced by contrast medium. II. Humans.

A new functional test is presented whereby the severity of peripheral obstructive disease can be evaluated during routine angiography utilizing the vasodilator effect of standard contrast medium. The hyperemic response following a sequence of 1 or 2 ml contrast injections into the iliac or femoral arteries is recorded by video dilution technique. The method allows quantitative measure of the functional state of the lower extremity. The vasodilator response in 10 normal human subjects and 23 patients with arterial obstructive disease in compared. Increasing depression of peak flow correlates with increasing symptomatology and a delay in the time to peak flow is seen with small vessel (outflow) disease. The functional severity of outflow disease (trifurcation and superficial femoral artery) as compared with inflow obstruction (iliac arteries) seen at angiography is documented by the test. A new staging of peripheral obstructive disease is proposed based on the results.

Angiography↗
PubMed1981

Angiographic measurement of coronary blood flow by video dilution technique.

A simplified video dilution technique has been developed whereby neither coronary dimensions nor contrast velocity need be measured to obtain coronary blood flow relative to a control flow. In 6 dogs, the distal left anterior descending coronary artery flow was measured by simultaneous electromagnetic flowmeter and video dilution technique. For the 236 paired measurements, the electromagnetic flow ranged from 23 to 196 ml/min for each series. When the first measure of a series was considered the control, the flow ratio difference between electromagnetic and video dilution values had a standard deviation of 12 per cent. When each series was broken into pairs, flow ratio difference between these values had a standard deviation of 10 per cent. Thus, the video dilution technique allows accurate measurement of coronary blood flow relative to a control state, utilizing only the known amount of contrast medium injected and the image from videotape replay of the injection. A patient is presented to illustrate the technique during coronary angiography. Applications include determination of coronary reserve during reactive hyperemia to assess the hemodynamic significance of coronary lesions, and determination of the effects of drugs upon coronary blood flow.

Angina Pectoris↗
PubMed1981

Renal flow response to contrast medium measured by video dilution technique.

The renal blood flow response following a sequence of small contrast medium injections was analysed in normal dogs and normal human subjects by video dilution technique. The results indicate that the video dilution technique offers an excellent opportunity in detecting abnormal flow responses in patients with renal hypertension.

Animals↗
PubMed1981

Regional distribution of cardiac output: normal values in man determined by video dilution technique.

Densitometry by video dilution permits regional blood estimation by a modification of the indicator dilution technique originally described by Stewart and Hamilton. Contrast mass is measured from the video fluoroscopic image rather than from dye concentration in blood withdrawn through a sampling catheter. From more than 400 studies, 70 patients who presumably had normal regional flows were selected. Flows in the cerebral, splanchnic, renal, and extremity circulations were determined as a percentage of ascending aortic flow (cardiac output). The regional flow determined by video dilution technique compare well with results of other techniques described in the literature. It is now possible to measure distribution of cardiac output to any major artery during routine angiography, thus providing another determinant of arterial adequacy. These normal values are currently used by the investigators as standards for the evaluation of patients with a variety of vascular diseases.

Angiography↗
PubMed1980

Video dilution technique. An accurate measure of blood flow during routine arteriography.

The video dilution technique for measuring blood flow consists of electronically and mathematically processing video-taped selective arteriograms to measure the flow in selectively catheterized arteries and to express this flow as a fraction of the flow in any reference artery. Flows were measured by video dilution and an electromagnetic flowmeter in ten dogs; the correlations were excellent. Video dilution flows were also measured in 105 patients. The technique is accurate, simple, and adds no risk to routine selective arteriography.

Adolescent↗
PubMed1980

Angiographic determination of splanchnic blood flow.

A new videodensitometric method of measuring blood flow in the splanchnic arteries as a fraction of the cardiac output was compared to electromagnetic flow readings in dogs. A previous investigation regarding the accuracy of the method in vitro was extended to prove that the videodensitometric technique was highly accurate also in vivo. The simplicity of the technique suggests that the videodensitometric method could be used to estimate blood flow in splanchnic arteries during routine angiography.

Absorptiometry, Photon↗
PubMed1980

Cerebral blood flow determination by video dilution technique in a patient with malignant chemodectoma.

Cerebral angiography performed on a patient with a preliminary diagnosis of jugular foramen syndrome revealed a highly vascular malignant chemodectoma supplied mainly by the left ascending pharyngeal artery. Blood flow was determined during angiography in the extracranial branches of the carotid arteries by video dilution technique. The decrease of blood flow after partial embolization of the left ascending pharyngeal artery was also quantified. The application and value of video dilution technique in blood flow determination, together with the angiographic findings are discussed.

Adult↗
PubMed1980

Angiographic determination of cerebral blood flow.

Determination of blood flow in the cerebral arteries as a fraction of the cardiac output was performed by the videodensitometric method and compared to electromagnetic flow readings in dogs. The method proved to be highly accurate in vivo confirming previous experiments in vitro. It is simple to perform during routine cerebral angiography and may produce significant physiologic data not readily available by other means.

Absorptiometry, Photon↗
PubMed1980

Determination of relative blood flow in single arteries: new video dilution technique.

A new concept for determining relative blood flow in single arteries using videodensitometry to obtain contrast dilution curves has been experimentally evaluated. Flow as a fraction of cardiac output in the cerebral, renal, splanchnic, and iliac arteries was determined in 110 measurements in 11 dogs. The mean difference between measurements by electromagnetic flow probe and videodensitometric values was less than 2%, and the correlation coefficient was r = 0.96 for all data. The method is simple compared to previous videodensitometric techniques, because the dimensions of the vessel and the mean transit time of the contrast bolus can be neglected. The necessary equipment includes a stable image intensifier-television chain, a videotape recorder, a videodensitometer, and a graphic recorder. The method is now used to measure blood flow in cerebral, coronary, splanchnic, renal, and ileofemoral arteries during routine clinical angiography.

Abdomen↗
PubMed1979

Selective embolization for control of gastrointestinal hemorrhage.

Transcatheter embolization using Gelfoam plugs or autologous clot is an alternative or adjunct to the conventional management of gastrointestinal hemorrhage. During a 12 month period we successfully treated 10 patients who had massive gastrointestinal hemorrhage with selective embolization; 6 patients had upper gastrointestinal hemorrhage and 4 had bleeding from the colon. Most of these patients were critically ill and were poor surgical candidates. Hemorrhage was controlled by selective catheterization of the bleeding vessel, followed by injection of Gelfoam pledgets. Since the procedure was accomplished with ease and prolonged hemostasis obtained, we recommend it for gastrointestinal hemorrhage, especially in patients who are poor surgical risks or are unresponsive to vasopressin infusion, or both. Operative intervention for the primary disease could subsequently be performed electively, if necessary, days or weeks after transcatheter embolization.

Adult↗
PubMed1979

Determination of blood flow through arteriovenous fistulae and shunts.

A videodensitometric method for estimating relative flow was employed in a patient with a bovine arteriovenous fistula. Analogous arteriovenous communications of different sizes were created in two dogs for comparison. Local and general hemodynamic parameters were measured. The videodensitometric method proved to be highly accurate compared to electromagnetic flow readings and is the method of choice in estimating shunt flow in connection with routine angiography.

Absorptiometry, Photon↗