Comparison of Fluoro and Cine Coronary Angiography

Balancing Acceptable Outcomes With a Reduction in Radiation Dose

Ayhan Olcay, MD; Ekrem Guler, MD; Ibrahim Oguz Karaca, MD; Mehmet Onur Omaygenc, MD; Filiz Kizilirmak, MD; Erkam Olgun, MD; Esra Yenipinar, RN; Huseyin Altug Cakmak, MD; Dursun Duman, MD

Disclosures

J Invasive Cardiol. 2015;27(4):199-202. 

In This Article

Discussion

The increasing use and complexity of imaging and interventional techniques have not been matched by increasing awareness and knowledge by prescribers and practitioners. The majority of doctors — including cardiologists — grossly underestimate the radiation doses for most commonly requested tests.[10,11] Interventional cardiologists are competitive and perfectionist-type people, but a recent publication about brain and neck tumors in interventional cardiologists should warn and encourage them to reduce radiation doses and perfection during procedures.[12] The significant increase in the cumulative exposure of patients and population to ionizing radiation, which is an important and potentially avoidable public health threat, is likely to increase the incidence of cancer in the future.[13]

Quantitative coronary angiography improved our ability to more accurately estimate the percent stenosis of a lesion and its length. Although this technique is a well-validated tool for accurately and reproducibly defining coronary lesion severity, these validations were done mostly in the cine film era using high-dose radiography and high-speed filming rates (60 frames/second). Its use, as originally validated, remains mostly in specialized research using experimental models and in clinical trials. With the transition to so-called lossless compression digital angiography, the use of lower-dose radiography, and the lower cine capture rates (15 frames/second), the information captured has been compromised.[14,15]

In our study, radiation doses were about 4 times higher in the cine group vs the LFH group. Fluoroscopy times were 2 times higher in the cine group vs the LFH group. Contrast use was prominently higher in the cine group vs the LFH group. Operators independently assessed LFH images adequate for decision making. With recent improvements in imaging equipment and software, fluoroscopic LFH image quality has greatly improved. Even perfect angiographic images on their own do not provide enough functional information without intravascular ultrasound, fractional flow reserve, or thallium scintigraphy; therefore, the need for a "perfect" angiographic image for clinical decision-making is disputable.

Visual stenosis estimates of three operators were tested statistically for intraclass variability for different vessels in the cine and LFH groups. Mean intraclass variability was not different between groups in the analysis, which supports our hypothesis that the LFH angiography technique can be used as reliably as the cine angiography technique. Extra radiation doses did not produce a difference in variability.

Consistent collimation, adequately low-level acquisition modes, fewer irradiating angulations, reduced magnification and full inspiration during radiography whenever possible, long source-to-skin, and short patient-to-detector distances are other important and effective techniques.[16] We did not use these effective techniques during this study, which would reduce radiation doses much more in both the LFH and cine groups.

LFH technique for coronary angiography should be tested in a larger population with different angiographic device brands despite interventional cardiologists' reluctance to select an examination protocol that intentionally sacrifices image quality. Management decisions given by cine and LFH angiographic images should be tested by fractional flow reserve, intravascular ultrasound, or thallium scintigraphy; if concordant results are obtained, the low-dose LFH technique for coronary angiography should universally be accepted by the clinicians in interventional cardiology and new industry standards in imaging should be established by device manufacturers.

In clinical practice, stenosis severity is typically determined during or shortly after the procedure and most commonly relies on visual estimation by physicians. This approach, however, has well-known limitations.[17,18] Older studies, conducted a decade or more ago, described interobserver and intraobserver variation in visual estimations of stenosis severity and inaccuracies compared with computer-assisted techniques, expert panel review, autopsy results, or simulations.[19–28]

Study Limitations

Some operators switched to cine mode when performing radial angiography because catheter engagement was weak and visualization was suboptimal. Some operators were dissatisfied with image quality and resisted using LFH angiography. One cardiac surgeon was not satisfied with images and requested cine images in his patient, but three other cardiac surgeons found images acceptable. In one case, additional cine images were obtained when there was a doubtful image. We propose that these techniques be used especially by experienced operators, and when in doubt additional cine images should be taken. There are also potential legal issues, wherein LFH images may cause problems in lawsuits. LFH, quantitative coronary angiography, fractional flow reserve, and thallium correlations should be performed to determine the safety of the LFH technique for diagnostic coronary angiography.

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