Background:
Radiation [stochastic and deterministic] exposes patients and providers that must be balanced against the benefits achieved. Data derived from high exposure events has resulted in a goal of ALARA [as low as reasonably achievable] with concerns at 50 mSv [single event], 100 mSV [proximate exposures], 400 mSv [lifetime exposure]. Cath lab patients may receive high radiation as a consequence of high risk/ complex procedures, obesity, prior PCI/CABG and lesion complexity [ESRD, calcified, CTO], structural disease, supported interventions. Initiatives to reduce radiation exposure include: procedure staging, collimation, mapping, decrease fluoro frame rates and cine run number/length.
Procedure:
Radiation of patients with invasive procedures in 2018 and 2019 with high exposure stochastic risk [Dose Area Product ≥20,000 μGy* m
2
( 200 Gy*cm
2
) or Skin Dose deterministic risk > 5 Gray were analyzed for associations and compared. Effective dose [0.23 mSy/Gy*m
2
] provides a lifetime risk of fatal cancer related to radiation.
Results:
Interventional volume increased from 1431 to 1547 PCI. The number and frequency of high DAP exposures decreased [237 to 161] and for 10 of 11 high volume operators; there was no decrease in high Skin Dose cases [83 versus 119]. Associations with high DAP rates: Surgical turndowns [14/161; 9%], high risk/complex procedures (e.g. rotablator [42/161; 26.1%], CTOs [27/161; 16.8%]), Obesity [100/161; 62%; Morbid Obesity 31/161; 19%]. Single vessel PCI patients comprised 41/161; 25.5% of high exposures with 10/41 [24% having a prior CABG]. Single event Dose Area Products were as high as 167,235 μGy* m
2
[effective dose 368 mSv; lifetime risk of fatal cancer 0.92%]; repeat procedures [up to 5 returns/ year with cumulative doses 10/161 in the 100-200 mSv range [1:200 -1:400 lifetime fatal cancer risk]. 36 of the 161 patients were ≤ 60 years old. Despite Skin Doses as high as 14 Gray no skin sequelae occurred. Operators varied in the frequency of high radiation procedures [highest volume 56/268; 21%; all others 105/1547; 8%], influenced by patient selection and procedure, but also by technical variables [e.g. fluoro verus cine, frame rate, collimation].
Conclusions:
Despite efforts, radiation exposure remains a concern, aggravated by the need for increasingly high risk, structural heart, and supported interventional procedures. Opportunities for improvement include: lab upgrade to improve imaging in progress, increase staging [CABG , multivessel PCI patients], limit runs/ frame rates, increase mapping, optimize collimation. Lifetime fatal cancer risk is higher in younger than older patients with similar exposures due to both the latency period for cancer development and the likelihood of repeat radiation exposure. Efforts are underway to limit and track the cumulative radiation exposure of patients.
Effective Dose to Patients during Cardiac Interventional Procedures (Khartoum-Sudan)