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Study Looks at Key Patient Factors Influencing Higher PCI Radiation

Author profile picture By L.A. McKeown

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Larger radiation doses during percutaneous coronary intervention (PCI) are linked with certain patient-specific factors, including high body mass index (BMI), history of bypass surgery, and the number of treated lesions, according to data from a large registry. Surprisingly, the study, published online September 24, 2013, ahead of print in Circulation: Cardiovascular Interventions, found no difference in radiation doses by access site.

Researchers led by Elmir Omerovic, MD, PhD, of University of Gothenburg (Gothenburg, Sweden), looked at data for angiography (n = 10,819) and PCI procedures (n = 9,850) carried out at 5 Swedish centers between January 1, 2008, and January 19, 2012. Radiation exposure and clinical data were collected as part of the Swedish Coronary Angiography and Angioplasty Registry (SCAAR). Access route was primarily radial (59%).

Age, Sex, Weight Implicated in Higher Dosing

Factors associated with increased radiation exposure were age, male sex, high BMI, diabetes, dyslipidemia, history of CABG, number of diseased vessels, number of lesions treated, and complex lesion type (table 1).

Table 1. Predictors of Higher Radiation Exposure

 

Estimated Regression Coefficient (95% CI)

P Value

Age, per 11.6 yrs

1.07 (1.06-1.08)

< 0.001

Male Sex

1.45 (1.42-1.48)

< 0.001

BMI, per 5.1 kg/m2

1.25 (1.24-1.26)

< 0.001

Diabetes

1.06 (1.03-1.08)

< 0.001

Dyslipidemia

1.02 (1.01-1.04)

0.013

Prior CABG

1.32 (1.28-1.35)

< 0.001

Number of Diseased Vessels

   1

   2

   3

 

1.15 (1.13-1.19)

1.26 (1.22-1.30)

1.30 (1.26-1.34)

 

< 0.001

< 0.001

< 0.001

No. of Lesions Treated

   1

   2

   3

   ≥ 4

 

1.62 (1.57-1.68)

1.95 (1.84-2.03)

2.34 (2.16-2.53)

2.83 (2.53-3.16)

 

< 0.001

< 0.001

< 0.001

< 0.001

Complex Lesion Type

   B1

   B2

   C

   CTO

   Bifurcation Lesion

 

1.03 (1.00-1.06)

1.05 (1.02-1.08)

1.11 (1.07-1.14)

1.39 (1.31-1.48)

1.14 (1.06-1.16)

 

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

 

Additionally, thrombus aspiration and the use of intraortic balloon pump or other assist devices also were associated with increased radiation exposure.

In secondary analysis to assess radiation risk by access site, median dose–area product values were similar for procedures performed via femoral and radial access (48 vs. 44 Gy cm2; P < 0.001). Likewise, median radiation exposures also were similar (79 vs. 73 Gy cm2; P < 0.001). After multivariable analysis, radial access route remained unassociated with increased radiation exposure (P = 0.67).

The study authors say the factors associated with higher radiation dose are useful to clinicians “so that patients can be adequately informed.

“Also, when treating complex or CTO lesions, especially in patients with high BMI or previous CABG, radiation management can be incorporated into preprocedure planning as well as in defining maximum levels that could guide physicians in decision making during the procedure accordingly,” Dr. Omerovic and colleagues write.

Reassurance About Radial

Although the general thinking is that radial procedures lead to higher radiation exposure, this study and a few others should change some minds, according to Stephen Balter, PhD, of Columbia University Medical Center (New York, NY).

“This is a large and enviable database and [the fact that] it is showing no difference between the radiation doses for radial vs. femoral to me is quite convincing and important,” he said in a telephone interview with TCTMD. “This is a purely European perspective, but I think it tells us that there is nothing about radial procedures that we need to be overly concerned about in terms of radiation exposure.”

Dr. Balter added that while knowledge of patient-specific characteristics leading to higher radiation exposures is important, it may often be irrelevant, especially in emergent cases where “you’re going to take the patient as they are and you are going to treat them.”

Study Details

Patients were primarily male (68%), and 18% had diabetes while 11% had a history of CABG. Mean BMI was 27.3 ± 5.1 kg/m2. Indications for angiography or PCI were STEMI (16%), unstable angina/NSTEMI (37%), and stable CAD (47%). 

Source:

Delewi R, Hoebers LP, Råmunddal T, et al. Clinical and procedural characteristics associated with higher radiation exposure during percutaneous coronary interventions and coronary angiography. Circ Cardiovasc Interv. 2013;Epub ahead of print. 

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Disclosures
  • Drs. Omerovic and Balter report no relevant conflicts of interest.

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