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D Katritsis

Publications and source records attributed to D Katritsis.

61 records · Page 4Linked to original sources
PubMed1990

Predictors of the rate of success of angioplasty of the left circumflex artery.

Out of 45 angioplasties attempted by the same cardiologist for stenosis of the left circumflex artery at St. Thomas' Hospital in a one and a half year period, six were unsuccessful due to inability to cross the lesion. In four of these cases, the lesion was crossed with the guide wire but not with the balloon. All these failures, and sixteen of the successful cases, were studied by means of geometrical analysis of the anatomy of the circumflex artery and computer-assisted automated quantitation of digital subtraction coronary angiograms obtained at the time of the procedure. The quantitative characteristics of the lesion (the proportional diameter of the stenosis; the proportional geometric area of the stenosis and the proportional densitometric area of the stenosis) were not significantly different between the cases resulting in failure or success. Similarly, the angles of the circumflex artery proximal to the stenosis, the distance of the lesion from the orifice of the artery and the length of the main stem of the left coronary were not different between the two groups. The group in which the angioplasty was unsuccessful had significantly longer lesions, however, whereas the ratios of the diameter (or the geometric area) of the distal part of the vessel beyond the lesion as compared with the proximal (reference) part were significantly lower in the group undergoing successful dilatation. We conclude that neither the angulation of the circumflex artery as it appears on a two-dimensional projection nor the proportional diametric stenosis of the lesion can serve as easily assessible predictors fro the success of the procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1989

Use of a hollow wire to facilitate angioplasty of occluded vessels.

An USCI 0.038 inch (0.97 mm) floppy tipped hollow wire was used to facilitate the passage of angioplasty guide wires across severe stenoses or vessel occlusions before balloon angioplasty. The hollow wire was passed through a standard 7 or 8 French gauge Judkins coronary catheter to establish whether the obstruction could be breached. This reduced the cost of failure because angioplasty guiding systems were not committed to procedures that were unlikely to be successful. The hollow wire provides stability for the passage of the guide wire and can be used to measure distal pressure and inject contrast. To date it has been used in a total of 15 cases of occluded vessels; it failed to cross the lesion in four cases. Successful angioplasty followed in all patients in whom the lesion was crossed.

Adult↗
PubMed1988

Assessment of coronary angioplasty: comparison of visual assessment, hand-held caliper measurement and automated digital quantitation.

Digital subtraction coronary angiograms (DSA) of 27 patients who had undergone coronary angioplasty (PTCA) to a total of 32 lesions were analyzed using an automated border-detecting computer program and hand-held caliper measurement of diameter percent stenosis. The results were compared with visual interpretation of the 35-mm cineangiograms. Visual reports significantly overestimated the pre-PTCA diameter percent stenosis (P less than .001) and underestimated the residual post-PTCA narrowing compared with the automatic computer program (P less than .001). Caliper measurements overestimated significantly the pre-PTCA stenosis in comparison with the computer (P less than .01), but post-PTCA the two methods did not differ significantly (P = .105). There was a positive but poor correlation between caliper and computer measurements (r = .43, P less than .05) performed on the pre-PTCA digital angiograms. Post-PTCA the two methods correlated better (r = 0.78, P less than .001), but further statistical analysis showed important discrepancies between them. The correlation of visual reports and computer measurements was poor pre-PTCA (Kendall's tau = 0.32, P less than .05) and not statistically significant post-PTCA (tau = 0.64, P = .5). We conclude that there is observer bias in the visual reporting of angioplasty results, so that pre-PTCA lesions are overestimated, whereas post-PTCA are underestimated. Hand-held caliper measurement improves the assessment of coronary stenoses in comparison with the visual report but still may not altogether eliminate observer bias; it may overestimate the pre-PTCA stenoses compared with automated border detection.

Analog-Digital Conversion↗
PubMed1988

Assessment of coronary angioplasty by an automated digital angiographic method.

Digital subtraction coronary angiograms (DSA) of 63 patients who had undergone coronary angioplasty (PTCA) for a total of 73 lesions were analyzed with an automated border-detecting computer program capable of simultaneous geometric and densitometric cross-sectional area estimation. The computer measurements were compared with visual interpretation of the 35 mm cineangiograms. The results indicated that visual reports of cineangiograms tend to overestimate the pre-PTCA diameter percent stenosis and to underestimate the post-PTCA residual stenosis in comparison with the computer (p less than 0.001 in bot cases). There was good agreement between geometric and densitometric area percent stenoses calculated by the program on the pre-PTCA digital angiograms (r = 0.82, p less than 0.001, mean of their differences = -0.2 with standard deviation = 6.1). Following PTCA, however, important discrepancies between the two methods existed (r = 0.71, p less than 0.001, mean of their differences = 1.0 with standard deviation = 18.6). Following PTCA (but not pre-PTCA), densitometric evaluation demonstrated a significantly greater mean coefficient of variation between different views (69%) than did the geometric evaluation on the same views (24%). We conclude (1) that visual interpretation of cine coronary angiograms compares poorly with quantitative methods for both the selection of PTCA candidates and the assessment of the results; (2) that the geometric and densitometric characteristics do not agree in describing the degree of post-PTCA residual stenosis; and (3) that after angioplasty, important discrepancies between densitometric evaluation in different views are observed.

Angiography↗