Traditional Versus Automated Injection Contrast System in Diagnostic and Percutaneous Coronary Interventional Procedures: Comp

Contrast-induced nephropathy is a frequent cause of hospital-acquired acute or chronic renal insufficiency in patients undergoing cardiac catheterization.1,2 The increasingly frequent use of contrast-enhancing imaging for both diagnosis and intervention in patients undergoing cardiac catheterization has generated concern about the avoidance of contrast-induced nephropathy. Though the precise mechanism (direct tubular injury, tubular obstruction, vasomotor instability or increase glomerular permeability to protein) has not been established, the amount of contrast agent is a predictor of acute renal function deterioration.3,4 Contrast injection with a manual stopcock-manifold system is the standard technique during diagnostic coronary angiography or percutaneous coronary intervention (PCI), but some operators favor the use of a power injector. The ACIST Injection System (ACIST™; ACIST Medical Systems, Eden Prairie, Minnesota) is a new automatic injection device that allows online hemodynamic monitoring, as well as control of injection rate and amount of contrast to be delivered.5 The use of an automatic injection pump has been found safe, reliable, predictable and convenient when used for coronary angiography and PCI.6–9 Previous studies that compared the traditional manual injection technique to an automatic injector have shown equivalent image quality.10,11 This study compared the amount of contrast volume delivered using the two methods of contrast injection: the traditional one (manual injection plus standard power injection for the left ventriculography using ANGIOMAT-6000) versus the new ACIST System programmed injector. Methods Patient population. Between January 2001 and May 2001, a total of 453 consecutive patients underwent diagnostic cardiac catheterization and/or PCI at our institution. Patients were randomly assigned to either automated contrast injection with the ACIST device (n = 253) or to conventional contrast injection using a stopcock-manifold system and contrast injection by hand syringe (n = 200). In addition, left ventriculography was performed in the latter group using ANGIOMAT 6000 power injection. Patients were randomly selected and were assigned to one of the two functioning cath labs at our institution, one of which is equipped with the ACIST device. Clinical, angiographic and procedure-related information was obtained from online medical records. Procedure description. The ACIST Injection System is a software-controlled, variable rate, self-purging syringe injector connected to an automated manifold without stopcocks. It supplies contrast media to a catheter at a user-determined variable flow rate that can be instantaneously and continuously varied. The user can control the flow rate of contrast media from the injector to the catheter with a user-actuated proportional hand controller. By operating this hand controller, the user can vary the flow rate of the contrast media from the injector and therefore the volume of contrast media or saline flush delivered to the patient. The automated manifold facilitates the performance of left ventriculography by simply selecting a different injection mode using the touch screen. Left ventricular pressure can be assessed online continuously through the pigtail catheter immediately prior and after ventriculographic injections without losing pressure during disconnection and reattachment from the manual manifold. Conversely, the manual method used in the control group required the usual repetitive manipulation of the stopcock-manifold system and contrast injection by hand syringe. Left ventriculography was performed in these patients by attachment to an automated injection system (ANGIOMAT 6000 power injection). The total amount of contrast volume used in each group was compared according to the procedure type, e.g., for diagnostic catheterization (140 patients in the ACIST group versus 97 in the control group), for diagnostic catheterization plus PCI (99 patients in the ACIST group versus 92 in the control group) and PCI alone (14 patients in the ACIST group versus 11 in the control group). The total amount of contrast volume given per patient, including the amount of the contrast material wasted outside the patient (bottle, manifold and syringe in the ACIST group and the pump system in the study group), was also taken into account. In the ACIST group, residual contrast material was discarded at the end of the day; in the manual injection group, residual contrast material was discarded after each procedure in order to avoid contamination. Fluoroscopy and total procedural times were registered in both groups. Statistical analysis. All data were collected prospectively and are expressed as means ± the standard error of mean. The difference in amount of contrast media used between the two groups was expressed as the absolute difference of the mean and as percentages. The data were analyzed using Chi-square test. The level of significance was p Conclusion. The use of the ACIST powered mode of contrast injection during both diagnostic coronary angiography and/or PCI allows the use of a significantly smaller amount of contrast media (both used and delivered) to the patient during the procedure.

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