Contrast-sparing devices have been slowly adopted into routine patient care. Randomized trial evidence of automated contrast injectors (ACIs) has not been analyzed to evaluate the true reduction in contrast volume during coronary angiography and intervention. It has been thought that reducing the amount of contrast exposure will result in a simultaneous reduction in the risk of contrast-induced nephropathy (CIN). Therefore, we sought to synthesize published evidence on contrast-sparing devices, contrast volume, and the incidence of CIN. We searched Medline, the Cochrane Library, and Clinicaltrials.gov . The search criteria included ACIs versus manual injection, contrast media volume, and the incidence of CIN. Data were extracted by 2 independent reviewers. The weighted mean difference of contrast volume was calculated using random effects models in RevMan, version 5.4.1, software to derive a summary estimate. A total of 79,694 patients from 10 studies were included (ACI arm, n = 20,099; manual injection arm, n = 59,595). On average, ACIs reduced contrast volume delivery by 45 ml/case (p <0.001, 95% confidence interval −54 to −35). The CIN incidence was significantly reduced by 15%, with an odds ratio of 0.85 (p <0.001, 95% confidence interval 0.78 to 0.93) for those using ACIs compared with manual injection. In conclusion, the use of ACIs in angiography significantly reduces the volume of contrast delivered to the patient and the incidence of CIN.
To date, several studies have compared manual injection and automated contrast injectors (ACIs) and have reported a reduction in contrast volume administered with use of ACIs. The studies have varied in the reported reduction of contrast for diagnostic catheterization. Others have also included the contrast volume used during percutaneous coronary intervention (PCI). However, a significant gap exists in summarizing the evidence from the published data. With several studies reporting varying results in the use of ACIs compared with manual injection, a meta-analysis or systematic review of the current research was required. The sample size of several of the studies was small, and the combined power of a meta-analysis could allow for a more powerful conclusion from the evidence. Therefore, we conducted a meta-analysis examining the currently published evidence on the reduction of contrast volume and the possible reduction of contrast-induced nephropathy (CIN) with the use of ACIs versus manual injection. Several studies have reported the effects of ACIs on the volume of contrast used during coronary angiography; fewer studies have examined the effects of contrast volume on renal function. We hypothesized that (1) contrast-sparing devices would reduce the total contrast volume used during diagnostic and interventional cases; and (2) through the reduction of contrast volume, the incidence of CIN would also be reduced.
Methods
We searched MEDLINE (through April 2013), ClinicalTrials.gov , and the Cochrane Library, for clinical trials comparing ACIs and manual injection and whether the contrast media volume and/or CIN rates had been reported. As of April 2013, 62 potentially relevant reports were identified. We also did a manual search on the cross-references included in the present meta-analysis.
Key word MESH terms included “automated injection,” “manual injection,” “automated contrast injectors,” and “ACIST” for the ACIST Injection System (ACIST Medical Systems, Eden Prairie, Minnesota). The studies were included if they compared the amount of contrast volume delivery between ACIs and manual manifold injection systems in patients undergoing diagnostic coronary angiography and/or ad hoc PCI. The exclusion criteria were the absence of a manual injection arm or failing to report the delivered contrast volume. The data were abstracted using appropriate methods according to the Quality of Reporting of Meta-analysis statement. Two of us (K.M., H.K.) independently reviewed the studies and recorded the information outcomes on spreadsheets. Study quality was assessed using the Jadad criteria ( Table 1 ).
| Study | Intervention | Patients (n) | Protocol | Enrollment Criteria | Study Type | RCT | Jadad Score |
|---|---|---|---|---|---|---|---|
| Anne et al, 2004 | Automated injection | 253 | Contrast injection with ACIST device | Catheterization and/or PCI | Prospective | + | 2 |
| Manual injection | 200 | Manual contrast injection using stopcock-manifold system | |||||
| Brosh et al, 2005 | Automated injection | 117 | Contrast injection with ACIST device | Catheterization and angiography or PCI | Prospective | + | 1 |
| Manual injection | 95 | Manual injection with hand syringe | |||||
| Call et al, 2006 | Automated injection | 377 | ACI | Catheterization and PCI | Retrospective observational | 0 | 1 |
| Manual injection | 1,798 | Manual injection with hand syringe | |||||
| Chahoud et al, 2001 | Automated injection | 47 | Contrast injection using 4F ACIST device | Catheterization and coronary arteriography | Prospective | + | 1 |
| Manual injection | 49 | Manual injection with 4F catheter | |||||
| Godley et al, 2012 | Automated injection | 7,970 | Contrast injection using ACIST device | Catheterization and ad hoc PCI | Retrospective observational | 0 | 1 |
| Manual injection | 5,137 | Manual injection | |||||
| Gonzalez et al, 2010 | Automated injection | 80 | Contrast injection using 4F catheter | Catheterization | Prospective | + | 1 |
| Manual injection | 84 | Manual injection with 6F catheter | |||||
| Gurm et al, 2013 | Automated injection | 9,995 | Automated injection with ACIST; catheter size per operator preference | PCI | Propensity matching retrospective observational | 0 | 1 |
| Manual injection | 50,889 | Manual injection; catheter size per operator preference | |||||
| Hwang et al, 2013 | Automated injection | 306 | Contrast injection using Avanta Fluid Management injection system (MEDRAD, INC., Warrendale, Pennsylvania) | Catheterization and ad hoc PCI | Prospective | + | 1 |
| Manual injection | 1,052 | Manual injection with 6F catheter | |||||
| Hou et al, 2010 | Automated injection | 856 | Contrast injection using 4F ACIST device | Coronary angiography | Prospective | 0 | 0 |
| Manual injection | 960 | Manual injection with 6F catheter | |||||
| Khoukaz et al, 2001 | Automated injection | 47 | Contrast injection using 4F ACIST device | Catheterization and coronary arteriography | Prospective | + | 1 |
| Manual injection | 46 | Manual injection with 6F catheter |
Summary statistics were calculated using the Cochrane Collaborative software, RevMan, version 5.4.1 (Baltimore, Maryland). We tested for heterogeneity using the I 2 test. Heterogeneity was observed in the diagnostic and ad hoc comparisons. Therefore, a random effects model was used to account for the existing heterogeneity across the studies. The weighted mean difference and 95% confidence intervals (CIs) were calculated for the contrast volume delivered and fluoroscopy time. The methods used for the calculation have been previously described.
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