Radiation Exposure During Transcatheter Valve Replacement: What Cardiac Surgeons Need to Know

A novel comprehensive radiation shielding system eliminates need for personal lead aprons in the catheterization laboratory

OBJECTIVES

This clinical study evaluated the efficacy of a novel radiation shielding system for the cardiac catheterization laboratory designed to provide comprehensive protection that obviates the need for personal lead aprons.

BACKGROUND

Invasive Cardiologists are exposed to occupational health hazards related directly to radiation exposure (RE) and indirectly to the orthopedic burden of wearing only partially protective lead aprons. Innovations to reduce these risks are warranted. A novel comprehensive shielding system (Protego^TM , Image Diagnostics Inc, Fitchburg, Ma) has been validated in pre-clinical studies to provide excellent radiation protection, sufficient for the State of Michigan to certify it for use without need for personal lead aprons.

METHODS

This clinical analysis measured RE to a single Physician operator utilizing the Protego^TM shield (and not wearing personal lead apron) during routine cardiac catheterization procedures (diagnostic and interventional). RE was measured at both thyroid and waist level with a real-time dosimetry system (Raysafe^TM , Billdal, Sweden), calculated on a median per case basis (mrems). Additional parameters collected included procedure type, access site, per case fluoroscopy time, and patient factors including body mass index.

RESULTS

In n=98 cases (25% diagnostic, 75% interventional including 22% chronic total occlusions), median/case RE was 0.4 mrems (thyroid) and 0.2 mrems (waist). RE=0 in 12 cases. In no case did radiation exposure exceed 3.2 mrems.

CONCLUSION

The Protego^TM shield system provides excellent RE protection to the Physician operator, without the need for personal lead aprons and has the potential to reduce catheterization laboratory occupational health hazards.

Feasibility of transcaval access TAVI in morbidly obese patients: A single-center experience

OBJECTIVES

We report a single-center experience in utilizing the transcaval-access transcatheter aortic valve implantation (TAVI) as an alternative approach in morbidly obese patients.

BACKGROUND

Morbidly obese patients present frequently for TAVI. Transfemoral arterial access TAVI in these patients is technically challenging due to deep arterial access, resulting in a higher risk of vascular complications. Transcaval access TAVI is increasingly used in patients with prohibitive iliofemoral arterial access.

METHODS

We used the transcaval approach for eight morbidly obese patients who had otherwise technically feasible femoral arterial access. This technique provides an alternative arterial access point that potentially circumvents some of the challenges relating to femoral arterial access.

RESULTS

We report eight morbidly obese patients with a mean body mass index of 42.3 ± 6.2 kg/m² who underwent transcaval access TAVI at our center (mean EuroScore II 2.47 ± 1.83%). The patient mean age was 70.3 ± 9.8 years; six were female. All eight patients underwent a successful and uncomplicated procedure. The median time to discharge was 2 days and all patients were alive at 30 days.

CONCLUSIONS

Transcaval access TAVI is a feasible alternative for morbidly obese patients and may reduce vascular complications. Further data are required to evaluate the safety of this approach.

Operator Radiation Exposure During Transfemoral Transcatheter Aortic Valve Replacement

Background

The level of radiation exposure received by operators performing transcatheter aortic valve replacement (TAVR) is not well investigated. The aim of this study is to measure the amount of radiation received by operators performing transfemoral TAVR and to identify various patient and procedural characteristics associated with increased radiation exposure.

Methods

Primary (operator 1) and secondary (operator 2) operators' equivalent radiation doses in micro Sieverts (µSv) were calculated prospectively using real-time radiation dosimeters for a total of 140 consecutive transfemoral TAVRs. Corresponding eye and thorax radiation exposures between the operators were compared. Associations between various patient and procedural characteristics and the radiation exposure were tested using the t-test and Wilcoxon Mann-Whitney rank-sum test with Monte Carlo estimation. Multivariable regression analysis was also conducted.

Results

Operator 1 had significantly higher cumulative equivalent radiation exposure than operator 2 (86 µSv vs 38 µSv, p-value: <0.0001) which was consistent at the level of the thorax (67 µSv vs 22 µSv, p-value: <0.0001), but not at the level of the eye (16.5 µSv vs 15 µSv, p-value: 0.30). On multivariable analysis, patient obesity and intraprocedural complications were associated with higher radiation exposure to both operators. Ad hoc percutaneous coronary intervention led to excessive radiation exposure to the secondary operator.

Conclusions

Transfemoral TAVR is associated with a modest amount of radiation exposure to operators and is significantly higher for the primary operator than for the secondary operator.

A systematic review on the application of the hybrid operating room in surgery: experiences and challenges

The hybrid operating room has been widely applied in different surgery sub-specialties. We aim to identify the advantages of hybrid operating rooms by focusing on intraoperative imaging and explore what to do for further improving its application. We searched related literature in websites including Pubmed, MEDLINE, Web of science, using the keywords ("hybrid operating room" or "integrated operating room" or "multifunctional operating room") and ("surgery" or "technique" or "intervention" or "radiology"). All the searched papers were screened and underwent quality evaluation. A total of 30 literature was eventually identified after full-text screening. These articles covered 10 countries and presented data for 15,558 individuals. The median sample size was 536 (range 8-12,804). Application of the hybrid operating room in general surgery, neurosurgery, thoracic surgery, urology, gynaecologic and obstetrics surgery, cardiovascular surgery, was summarized. Four different operative indicators were applied (operative duration, mortality rate, operation success rate and complication rate). A hybrid OR could significantly increase the operation success rate and reduce operative duration, mortality rates, and complication rates. Further efforts could be made to reduce radiation exposure in the hybrid operating room and increase its cost-effectiveness ratio.

Application of the Hybrid Operating Room in Surgery: A Systematic Review

BACKGROUND AND OBJECTIVE

The hybrid operating room has been widely applied in surgery, including neurology, general surgery, gynecology, and obstetrics. By reviewing application of the hybrid operating room in different categories of surgery, we aim to summarize both advantages and disadvantages of the hybrid operating room and discuss what to do for further improving the application of it.

METHODS

We searched related literature in websites including Pubmed, MEDLINE, Web of science, using the keywords "hybrid operating room", "surgery", "technique", "intervention", and "radiology". All the searched papers were screened and underwent quality evaluation. The eventually selected papers were carefully read, with related information extracted and summarized.

RESULTS

After screening and assessment, a total of 29 literature was collected. Application of the hybrid operating room in general surgery, neurosurgery, thoracic surgery, urology, gynecologic and obstetrics surgery, and cardiovascular surgery was summarized. Both advantages and disadvantages of the hybrid operating room were discussed in order to improve application of the hybrid operating room in surgery.

CONCLUSIONS

Surgeries performed in the hybrid operating room take advantages over those conventional operating rooms mainly in terms of higher procedure accuracy, less operative time, and less risk of hemorrhage during the transportation between radiology departments and operating suites. Further efforts should be made to reduce radiation exposure from imaging systems equipped in the hybrid operating room and increase cost-effectiveness ratio of the hybrid operating room.

Radiation Exposure During Transcatheter Aortic Valve Replacement: Impact of Arterial Approach and Prosthesis Type

BACKGROUND

The impact of novel alternative access and valve type on radiation exposure during transcatheter aortic valve replacement (TAVR) has not yet been evaluated. This study sought to determine the impact of a transarterial approach and prosthesis type on physician and patient exposure to radiation during TAVR.

METHODS

This was a prospective study including 140 consecutive patients undergoing TAVR by transfemoral (n = 102) or transcarotid (TC) (n = 38) access at 2 centers. Implanted valves were the self-expanding Evolut R/PRO system (Medtronic, Minneapolis, MN; n = 38) and the balloon-expandable SAPIEN 3 valve (Edwards Lifesciences, Irvine, CA; n = 102). The primary endpoint was first operator radiation exposure. The secondary endpoint was patient radiation exposure.

RESULTS

First operator radiation exposure was 4-fold greater during TC TAVR (P < .001). The use of a self-expanding valve was associated with a longer x-ray time (P = .015) and a 2-fold greater first operator radiation dose (P = .018). Patient radiation dose was not significantly affected by arterial approach (P = .055) or valve type (P = .095). After adjustment for potential confounders, the TC approach remained associated with a 174.8% (95% confidence interval, 80.6-318.3, P < .001) increase in first operator radiation dose, whereas the use of a self-expanding valve no longer influenced the first operator dose (P = .630).

CONCLUSIONS

TC access and the use of a self-expanding valve were associated with a 4- and 2-fold greater first operator radiation exposure during TAVR procedures, respectively. Unlike the arterial approach, the effect of bioprosthesis type on radiation exposure was mainly related to x-ray time and was no longer significant after adjustment.