Evaluation of new 4 French catheters by comparison to 6 French coronary artery images

The use of 4 Fr catheters for diagnostic coronary arteriography improves pa tient comfort and could potentially reduce costs by decreasing arterial com plications and encouraging outpatient examination. We examined the performa nce of recently developed 4 Fr catheters (100 cm long, 0.042 inch internal diameter) through in vitro flow rate patterns and in vivo image quality. Fl ow patterns (flow rate calculated from pressure with the Hagen Poiseuille r elation) were obtained by hand (10 ml volume; maximal effort, one-handed fu ll injection) and power injection (10 mi volume; 5 ml/sec) in the 4 Fr cath eters were compared to 5 Fr (0.047 inch) and 6 Fr (0.057 inch) catheters. I n 20 patients, coronary arteriograms were obtained from 4 Pr hand injection (4 HI), 4 Pr power injection (4 PI), 6 Fr hand injection (6 HI), and 6 Fr power injection (6 PI) were compared after being scored into 5 grades. Coro nary diameter was assessed at two sites for all injections in the same grou p of patients. In power injections, peak flow rates were consistently 5.5 ml/sec in all ca theters. Hand injections were much more variable; peak flow rate ranges for 5 different physicians were 3.5-6.0 ml/sec. in 6 Pr, 1.8-3.0 ml/sec. in 5 Fr and 1.4-2.0 ml/sec in 4 Fr catheters. Mean image scores of left arteriograms were significantly higher for 4 PI v ersus 4 HL and for 6 Pr images compared to 4 PI (p < 0.001). In right arter iograms, 4 HI scored significantly lower than other methods (4 PI, 6 HI and 6 PI; p < 0.001). In 4 HI left coronary arteriograms, the frequency of gra de > 2 was 96% and > 3 was 82%. Power injection improved 4 Fr imaging to 99 % greater than grade 2 and 93% greater than grade 3. There were no differen ces in the frequency of images above grade 3 in right coronary arteriograms . Measured coronary artery diameters at 40 normal and 17 stenotic sites by OCA analysis (Acom, Siemens AZ, Erlangen, Germany) did not influence the st udy data. We concluded that coronary arteriograms by hand injection with 4 Fr cathete rs were inferior compared to 6 Fr images. Power injection and/or larger cat heters may be necessary to ensure the highest quality images are obtained.