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Biomedical subjects

S Paulin

Publications and source records attributed to S Paulin.

At least 37 records · Page 2Linked to original sources
PubMed1984

Left ventricular wall motion analysis using operator-independent contour positioning.

A method has been developed for the analysis of left ventricular wall motion which obviates the operator's involvement in the relative positioning of the systolic and diastolic contours. This was achieved by maximizing the cross-correlation function for the two silhouettes . The technique was compared with a standard method requiring the operator's definition of a long axis for the left ventricle. The results for 21 normal angiograms showed that with the cross-correlation technique the confidence region of the wall motion curves was markedly narrower and the symmetry in the contractile pattern between the anterior and posterior wall segments was better than with the standard technique. Statistical concepts for narrowing the normal group and the sources of errors in the analysis are discussed.

Adult↗
PubMed1983

The minimum error in estimating coronary luminal cross-sectional area from cineangiographic diameter measurements.

A formal analysis of the error associated with the use of radiographic diameter measurements in estimating the luminal area of an elliptically-shaped coronary cross-section was performed. When two views are available, the maximum potential error was found to decrease rapidly as the angle between the views increased to 90 degrees, but this error was small (less than 25%) for orthogonal views only for mild degrees of ellipticity (major/minor axis ratio less than 2). Since, for each successive doubling of the number of radiographic views, a stepwise reduction in the potential error by an approximate factor of only one-half was found, a large number of views is required to eliminate the potential error associated with diameter assessment of highly elliptical lumena.

Cineangiography↗
PubMed1983

A catheterization technique for reproduction of a human atherosclerotic lumen within the dog coronary artery in vivo.

Reproduction of a human atherosclerotic lumen within the arterial lumen of an intact animal would facilitate angiographic and hemodynamic studies of stenoses. Accordingly, a male silicone rubber cast of a human atherosclerotic lumen was obtained from a cadaver artery, and a thin-walled replicate arterial phantom was constructed from the cast by use of a rapidly polymerizing liquid plastic. The casting properties of both materials were such that the topography of the arterial lumen was duplicated precisely in the phantom with 20 x microscopic detail preserved. The phantom was coated with a banzalkonium-heparin solution and introduced over a guidewire into an epicardial segment of a coronary lumen of the dog. Similarly, a larger phantom was placed within the dog femoral artery either directly via an arteriotomy or indirectly via a catheterization technique. Since the plastic material used to make a phantom had the same radiographic density of tissue, the angiographic appearance of an intra-arterial phantom was that of a human stenosis.

Animals↗
PubMed1983

In vivo coronary angioscopy.

The feasibility of in vivo coronary angioscopy was tested utilizing a 1.8 mm angioscope in vessels where blood had been replaced by optically clear liquids, including a new perfluorocarbon emulsion. After trials in postmortem canine and human coronary arteries, in vivo intraluminal visualization was accomplished in the dog with a catheterization technique and in patients during open heart surgery. The results demonstrate the feasibility and potential clinical usefulness of direct visualization of intravascular anatomy and disease, analogous to endoscopy of other organ systems.

Animals↗
PubMed1983

Computerized image analysis for quantitative measurement of vessel diameter from cineangiograms.

Subjective estimates of the angiographic severity of coronary artery stenoses show variability and inaccuracy. We therefore tested the accuracy of a newly developed computerized image analysis system for quantitating vessel diameter from cineangiograms. Fourteen cylindrical phantoms of known diameter were filled with contrast medium and filmed over a wide range of clinically relevant radiographic conditions in order to develop regression equations that related computer-derived to anatomic diameters. Computer measurements of vessel diameter were unaffected by vessel size, magnification, focal spot size, thickness of scattering medium, kilovolt peak, or location within the radiographic field, but a correction factor was necessary for a small but significant (p less than .01) linear dependence on contrast medium concentration. The accuracy of computerized vessel diameter measurements ranged between +/- 59 and +/- 137 mu for all conditions except for rapid vessel motion and contrast medium concentrations of 50% or less meglumine diatrizoate (Renografin 76), both of which resulted in reduced accuracy as well as in the inability to locate lumen edges of vessels less than 1 mm in diameter.

Cineangiography↗
PubMed1983

Fluorescence of experimental atheromatous plaques with hematoporphyrin derivative.

Fluorescence of hematoporphyrin derivative (HPD) has been used clinically to localize malignant neoplasms because of its selective accumulation in these tissues. We tested the hypothesis that HPD may also be selectively concentrated within atheromatous plaques. 48 h after HPD injection in a variety of species, selective fluorescence of atheromatous plaques of the aorta was seen in each animal (rabbits and Patas monkey) exhibiting such lesions. No fluorescence could be demonstrated in aortic segments free of atheromatous involvement. Since the efficacy of photodynamic destruction of malignant tumors with HPD has been demonstrated in clinical studies, the observations of the present study may have therapeutic implications in atheromatosis.

Animals↗
PubMed1982

Mortality related to cardiac catheterization and angiography.

During a 14-month period, 75 deaths occurring in relation to 53,581 cardiac catheterizations were consecutively and prospectively reported to the Registry Committee of the Society for Cardiac Angiography. Three of the patients died several days after their catheterization from an unrelated cause and are excluded from this analysis. There were 21 patients (group I) who arrived at the laboratory in extremis and whose deaths were expected irrespective of the catheterization. Most of these patients suffered from recent myocardial infarctions and cardiogenic shock, or had complex congenital malformations. In 35 patients (group II), a cardiovascular complication occurring during the catheterization resulted in death. In 16 patients (group III) catheterization seemed uneventful, but death occurred suddenly 10 min to 10 h after the procedure. Of these 16 patients, eight had left main coronary artery obstruction greater than or equal to 90%, five had three-vessel disease all with 90% obstructions, one had 2-vessel disease both with 90% obstructions, and who had critical aortic stenosis. The 51 unexpected deaths (groups II and III) were considered to be causally related to the procedure, a mortality rate of 0.10%. Subsets with an increased mortality rate (M), were patients with: a) left main disease greater than 50% (M = 0.94%); b) ejection fraction less than 30% (M = 0.54%); c) NYHA class III or IV (m = 0.24%); d) age over 60 years (M = 0.23%); or e) three-vessel disease (M = 0.13%). In conclusion, catheterization related mortality occurs mostly in patients with far advanced cardiac disease. Nearly 1/3 of the unexpected deaths occurred suddenly after a seemingly uneventful procedure. Close monitoring after catheterization of patients with similar characteristics (left main disease greater than or equal to 90%, or three-vessel disease all greater than or equal to 90%) might disclose avenues for reducing mortality occurring after catheterization.

Adolescent↗
PubMed1982

Functional alterations in the coronary circulation as mirrored in the angiogram.

The ability of coronary arteriography to disclose the presence of abnormalities in the coronary arteries is undisputed. On the other hand, it is less clear whether the angiographic examination of the coronary circulation permits an assessment of functional abnormalities, which may involve the coronary circulation in toto or regionally. The most commonly practiced grading of angiographically demonstrated coronary artery disease is based on the degree of arterial narrowing and the number of major vessels that are involved. This approach, however, suffers from significant shortcomings, which are mainly related to the limitations in accuracy of measuring such lesions angiographically. Secondary angiographic signs of impaired coronary flow, such as contrast propagations through collateral channels, delayed, stagnant, and reciprocal flow pattern, and the appearance of excessive peripheral myocardial contrast accumulation may gain great importance. In conjunction with the presentation of a number of cases considered to be representative for different situations of chronic and acute myocardial ischemia, the primary and secondary angiographic findings are accounted for in detail and discussed as to the most likely existing pathophysiology. The discussion also includes knowledge based on experiments performed in in vitro or animal models and tries to establish a synthesis between the different angiographic phenomena and the present status of our understanding of the pathophysiology of myocardial injury. It is concluded that such detailed analysis of the angiographic events may yield important information for the most appropriate management of the individual patient.

Coronary Angiography↗
PubMed1982

Successful streptokinase treatment of a thrombosed, ectopic coronary artery: a case report.

Early reperfusion of a thrombosed, ectopically arising coronary artery was accomplished by selective streptokinase infusion therapy. Familiarity with the most common variations of coronary artery orifices and/or divisions of major branches is important for the angiographer to ensure that selective catheterization of the involved artery can be accomplished promptly.

Aged↗
PubMed1982

Experimental myocardial ischemia II: radiographic contrast media toxicity.

The comparative effects of meglumine sodium diatrizoate (MSD), sodium meglumine calcium metrizoate (SMCM), and metrizamide (M) were studied in an isolated canine heart preparation. The parameters observed were coronary blood flow (CBF), myocardial contractile force (MCF), positive and negative dF/dt, and perfusion pressure during normal and ischemic perfusion conditions. MSD had an initial negative inotropic effect but baseline MCF returned in 1 min during normal perfusion and 2 min under ischemic conditions. SMCM and M had only a positive inotropic effect under normal perfusion. However, during ischemia, the positive effect of SMCM was followed by a decrease in contractile force. M showed only a positive effect on force during ischemia. Our results indicate that calcium additive may increase the risk of coronary arteriography in patients with severe coronary artery disease.

Animals↗
PubMed1982

Thrombogenicity of heparin- and non-heparin-coated catheters: clinical trail.

Catheters used in clinical cerebral angiography were examined by scanning electron microscopy for buildup of thrombus. In 21 (67%) of 31 individuals studied with non-heparin-coated catheters, either cell aggregations or thrombi developed compared with seven (28%) of 25 individuals studied with heparin-coated catheters. The median size of the cell aggregations and thrombi on non-heparin- and heparin-coated catheters was significantly different (p less than 0.01). The slopes that estimated the probable rate of thrombus formation were also significantly different (p less than 0.01). This suggests the desirability of replacement of non-heparin-coated catheters if the angiographic procedure is extended.

Adult↗
PubMed1981

Myocardial salvage after intracoronary thrombolysis with streptokinase in acute myocardial infarction.

Nine patients with acute myocardial infarction had cardiac catheterization and intracoronary infusions of streptokinase 2.3 to 4.3 hours (mean, 3.5) after the onset of symptoms. Occluded coronary arteries were opened within approximately 20 minutes in all patients, but reocclusion occurred in one patient. The immediate effect of thrombolysis on myocardial salvage was assessed with the intracoronary injection of thallium-201. Improved regional perfusion, indicating myocardial salvage after recanalization, was observed in seven of the nine patients. One patient, who had also sustained a nontransmural infarction one week before, had no change after thrombolysis. In the ninth patient, recanalization of a coronary artery was followed by reocclusion and worsening of the myocardial-perfusion defect. Intracoronary thallium-201 studies two weeks and three months after streptokinase infusion in two patients were unchanged in comparison with scintiscans performed 1.5 hours after thrombolysis. These short-term observations suggest that recanalization of obstructed coronary arteries after intracoronary thrombolysis can salvage jeopardized myocardium, However, evaluation of the long-term effects of this procedure on survival and myocardial function will require controlled clinical trials.

Aged↗
PubMed1980

Crippled lung: variations on a theme by Macleod.

We have studied nine male patients (age 18 to 68 years) with radiographic and physiologic evidence of an abnormally small lung on one side (three right and six left). All had had a childhood pneumonia or bronchiolitis and eight had chronic or recurrent bronchitis and exertional dyspnea. Radiography showed two of the small lungs to be hypolucent while seven were hyperlucent. Bronchography revealed evidence of bilateral chronic bronchitis in all with saccular bronchiectasis in three. Angiography showed strikingly diminished vascularity to the smaller lung. Spirometry revealed airway obstruction in seven of the patients. All had pulmonary arterial hypertension. Radiospirometry showed that the small lung had on the average 30% of the total ventilation but only 15% of the perfusion. Washout of 133 Xe was extremely slow in radiolucent regions. We suggest the name "crippled lung" syndrome for this entity because it is purely descriptive and encompasses several clinical variants. It also avoids the pitfalls of etiologic implication (acquired-congenital). Clinical or subclinical bronchitis seems to be common in these patients and the prime goal in therapy must be to combat the tendency towards airway infection.

Adolescent↗