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Figure.
Risk of Cumulative Incidence of Cataract Surgery in Patients by Different Percutaneous Cardiac Intervention (PCI) Exposure Groups
Risk of Cumulative Incidence of Cataract Surgery in Patients by Different Percutaneous Cardiac Intervention (PCI) Exposure Groups
Table.  
Incidence of Cataract Surgery in Patients With and Without PCI Exposure
Incidence of Cataract Surgery in Patients With and Without PCI Exposure
1.
Mozaffarian  D, Benjamin  EJ, Go  AS,  et al; American Heart Association Statistics Committee and Stroke Statistics Subcommittee.  Heart disease and stroke statistics--2015 update: a report from the American Heart Association.  Circulation. 2015;131(4):e29-e322.PubMedGoogle ScholarCrossref
2.
Schömig  A, Mehilli  J, de Waha  A, Seyfarth  M, Pache  J, Kastrati  A.  A meta-analysis of 17 randomized trials of a percutaneous coronary intervention-based strategy in patients with stable coronary artery disease.  J Am Coll Cardiol. 2008;52(11):894-904.PubMedGoogle ScholarCrossref
3.
Vano  E, Gonzalez  L, Fernández  JM, Haskal  ZJ.  Eye lens exposure to radiation in interventional suites: caution is warranted.  Radiology. 2008;248(3):945-953.PubMedGoogle ScholarCrossref
4.
Jacob  S, Boveda  S, Bar  O,  et al.  Interventional cardiologists and risk of radiation-induced cataract: results of a French multicenter observational study.  Int J Cardiol. 2013;167(5):1843-1847.PubMedGoogle ScholarCrossref
5.
Ciraj-Bjelac  O, Rehani  M, Minamoto  A, Sim  KH, Liew  HB, Vano  E.  Radiation-induced eye lens changes and risk for cataract in interventional cardiology.  Cardiology. 2012;123(3):168-171.PubMedGoogle ScholarCrossref
6.
Fetterly  KA, Lennon  RJ, Bell  MR, Holmes  DR  Jr, Rihal  CS.  Clinical determinants of radiation dose in percutaneous coronary interventional procedures: influence of patient size, procedure complexity, and performing physician.  JACC Cardiovasc Interv. 2011;4(3):336-343.PubMedGoogle ScholarCrossref
Research Letter
May 2016

Incidence of Cataract Surgery in Patients After Percutaneous Cardiac Intervention in Taiwan

Author Affiliations
  • 1Department of Dermatology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
  • 2Department of Ophthalmology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
  • 3Department of Cardiology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
  • 4Master degree program in Aging and Long-Term Care, College of Nursing, Kaohsiung Medical University, Kaohsiung, Taiwan
  • 5Department of Public Health, College of Medicine, National Cheng-Kung University, Tainan, Taiwan
JAMA Intern Med. 2016;176(5):710-711. doi:10.1001/jamainternmed.2016.0554

More than 1 million percutaneous cardiac intervention (PCI) procedures are performed annually in the United States,1 resulting in some reduction of cardiovascular mortality.2 Because the correlation between occupational radiation exposure and excess risk of cataract formation in medical staff is well documented,3-5 ocular protection from radiation (ie, routine use of lead eye glasses) is recommended for interventionists. However, the risk of radiation cataract for patients undergoing PCI procedures has not drawn much attention, and there are no current guidelines for patient eye protection. Hence, we conducted this study to evaluate the risk of cataract in the population undergoing PCI procedures.

Methods

A retrospective, matched-cohort study was conducted using population-based representative claims data from Taiwan’s National Health Insurance (NHI) research database, which includes 1 million individuals. We used discharge procedure codes (International Classification of Diseases, Ninth Revision, Clinical Modification procedure codes 35.96, 36.0x, 37.21-37.23, 37.26, 37.27, 37.29, 37.34, and 88.5x) to identify patients who had recently undergone a PCI procedure (5-year washout period from 1996 to 2000) from January 1, 2001, through December 31, 2012. The date of the first PCI procedure was considered the index date for each patient. Patients were excluded if they were younger than 40 years, had a prevalent cancer (confounding by radiotherapy), or underwent cataract surgery before the index date. Controls were randomly selected from the NHI’s beneficiaries and matched 1:2 according to birth year, sex, and diabetes mellitus status (a major confounder in cataract). Index data for controls were assigned according to their matched patient. The end point of each study participant was determined by the date of cataract surgery, date of withdrawal from the NHI, or the end of 2012.

Cox proportional hazards regression model adjustment for potential confounders was used to assess the cataract risk. This study was approved by the institutional review board of Kaohsiung Medical University Hospital. The NHI research data were claims-based administration data set (secondary data). All the identifying markers were encrypted so the patients were deidentified.

Results

A total of 41 421 participants (13 807 exposed to PCI and 27 614 not exposed to PCI) were included. Patients who underwent a PCI procedure had a higher incidence of cataract surgery, and a dose-response effect was observed (Table). The overall adjusted hazard ratio for those exposed to PCI vs not exposed to PCI was 1.25 (95% CI, 1.17-1.34) and increased with the number of PCI exposures (Figure).

Discussion

We found that patients who underwent PCI procedures had a 25% increase in the incidence of cataract surgery with a dose-response relationship seen. The reasons for this association are many fold. First, the radiation dose of PCI was traditionally too low to cause immediately noticeable damage, and there is no reliable diagnostic method for detection of radiation cataract. Second, the common risk factors for coronary artery disease, such as diabetes mellitus, hypertension, smoking, and steroid use, also increase the incidence of cataract. Third, data on the safe radiation threshold for the lens are uncertain, and it is difficult to set regulations to limit lens exposure for PCI. Because this was an observational study, we cannot establish causation, and there may be unmeasured confounders. In Taiwan, more than 99% of residents are covered by the NHI system, so access to care is unlikely to be an issue.

In the past decade, procedures for complex cardiac conditions have become lengthier, and the need for additional procedures has become more common,6 which introduces higher accumulative radiation doses and increased risks for radiation damage. Therefore, PCI-associated radiation cataract may be an increasing concern.

In conclusion, this study found an association of PCI exposure with the need for cataract surgery. Thus, providing lead eye glasses to protect patients eyes, as is already done during cosmetic laser procedures, during the PCI procedures is recommended.

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Article Information

Corresponding Author: Yu-Tung Huang, PhD, Master degree program in Aging and Long-Term Care, College of Nursing, Kaohsiung Medical University, 100 Shih-Chuan First Rd, San-Ming District, Kaohsiung City, Taiwan 80708 (yah@kmu.edu.tw).

Published Online: April 4, 2016. doi:10.1001/jamainternmed.2016.0554.

Author Contributions: Drs Huang and Lu had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Study concept and design: All authors.

Acquisition, analysis, or interpretation of data: Wei, Bee, Wang, Huang.

Drafting of the manuscript: Wei, Bee, Wang, Lu.

Critical revision of the manuscript for important intellectual content: Wei, Bee, Wang, Huang.

Statistical analysis: All authors.

Administrative, technical, or material support: Wei, Lu.

Study supervision: Huang, Lu.

Conflict of Interest Disclosures: None reported.

References
1.
Mozaffarian  D, Benjamin  EJ, Go  AS,  et al; American Heart Association Statistics Committee and Stroke Statistics Subcommittee.  Heart disease and stroke statistics--2015 update: a report from the American Heart Association.  Circulation. 2015;131(4):e29-e322.PubMedGoogle ScholarCrossref
2.
Schömig  A, Mehilli  J, de Waha  A, Seyfarth  M, Pache  J, Kastrati  A.  A meta-analysis of 17 randomized trials of a percutaneous coronary intervention-based strategy in patients with stable coronary artery disease.  J Am Coll Cardiol. 2008;52(11):894-904.PubMedGoogle ScholarCrossref
3.
Vano  E, Gonzalez  L, Fernández  JM, Haskal  ZJ.  Eye lens exposure to radiation in interventional suites: caution is warranted.  Radiology. 2008;248(3):945-953.PubMedGoogle ScholarCrossref
4.
Jacob  S, Boveda  S, Bar  O,  et al.  Interventional cardiologists and risk of radiation-induced cataract: results of a French multicenter observational study.  Int J Cardiol. 2013;167(5):1843-1847.PubMedGoogle ScholarCrossref
5.
Ciraj-Bjelac  O, Rehani  M, Minamoto  A, Sim  KH, Liew  HB, Vano  E.  Radiation-induced eye lens changes and risk for cataract in interventional cardiology.  Cardiology. 2012;123(3):168-171.PubMedGoogle ScholarCrossref
6.
Fetterly  KA, Lennon  RJ, Bell  MR, Holmes  DR  Jr, Rihal  CS.  Clinical determinants of radiation dose in percutaneous coronary interventional procedures: influence of patient size, procedure complexity, and performing physician.  JACC Cardiovasc Interv. 2011;4(3):336-343.PubMedGoogle ScholarCrossref
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