The radiation issue in cardiology: the time for action is now

Prognostic Implication of Appropriateness Criteria for Pharmacologic Stress Echocardiography Performed in an Outpatient Clinic

Background—

Although appropriateness criteria for stress echocardiography have been developed to deliver high-quality care, the prognostic impact of these criteria remains undefined. Therefore, we sought to assess the prognostic implication of the American College of Cardiology/American Society of Echocardiography appropriateness criteria for pharmacological stress echo in a cohort of ambulatory patients.

Methods and Results—

The study population consisted of 1552 ambulatory patients who underwent pharmacological (752 dobutamine, 800 dipyridamole) stress echo for the evaluation of known (n=549) or suspected (n=1003) coronary artery disease at a single cardiology center. Patients were followed up for a median of 36 months. Indications were determined for consecutive studies by 2 reviewers and categorized as follows: 984 (63%) patients had appropriate, 145 (9%) uncertain, and 423 (27%) inappropriate indication for stress echo. Ischemia was present in 15% of patients with appropriate, 8% of those with uncertain, and 5% of those with inappropriate indication ( P <0.0001). During follow-up, 146 events (89 deaths, 57 nonfatal infarctions) occurred. Annual event rate associated with appropriate, uncertain, and inappropriate study was 3.1%, 3.8%, and 1.3%, respectively. The abnormal test result in patients with appropriate, uncertain, and inappropriate study was associated with 5.0%, 5.6%, and 1.8% annual event rate, respectively, exerting an independent value only in the appropriate and uncertain subset.

Conclusions—

Inappropriate indication for pharmacological stress echo is common, being documented in about 1 of 4 patients evaluated in an ambulatory setting, and is associated with lower rate of positive results and better survival as compared with appropriate and uncertain indication.

Cancer and non-cancer brain and eye effects of chronic low-dose ionizing radiation exposure

BACKGROUND

According to a fundamental law of radiobiology ("Law of Bergonié and Tribondeau", 1906), the brain is a paradigm of a highly differentiated organ with low mitotic activity, and is thus radio-resistant. This assumption has been challenged by recent evidence discussed in the present review.

RESULTS

Ionizing radiation is an established environmental cause of brain cancer. Although direct evidence is lacking in contemporary fluoroscopy due to obvious sample size limitation, limited follow-up time and lack of focused research, anecdotal reports of clusters have appeared in the literature, raising the suspicion that brain cancer may be a professional disease of interventional cardiologists. In addition, although terminally differentiated neurons have reduced or mild proliferative capacity, and are therefore not regarded as critical radiation targets, adult neurogenesis occurs in the dentate gyrus of the hippocampus and the olfactory bulb, and is important for mood, learning/memory and normal olfactory function, whose impairment is a recognized early biomarker of neurodegenerative diseases. The head doses involved in radiotherapy are high, usually above 2 Sv, whereas the low-dose range of professional exposure typically involves lifetime cumulative whole-body exposure in the low-dose range of < 200 mSv, but with head exposure which may (in absence of protection) arrive at a head equivalent dose of 1 to 3 Sv after a professional lifetime (corresponding to a brain equivalent dose around 500 mSv).

CONCLUSIONS

At this point, a systematic assessment of brain (cancer and non-cancer) effects of chronic low-dose radiation exposure in interventional cardiologists and staff is needed.

Mitral valve treatments on the horizon

Three new treatment methods under development for FunctionalMitral Regurgitation are described.