Routine pre-procedure laboratory testing for patients undergoing outpatient cerebral angiography is not indicated

Cerebral angiography is a routine low-risk procedure. Laboratory testing is performed in almost all patients. Some testing may be warranted in selected patients but can also result in delays in performing the procedure.

To determine if routine pre-procedure testing for outpatient cerebral angiography is necessary.

447 patients who underwent outpatient cerebral angiography were reviewed. The tests were evaluated for any abnormality, correlation of the abnormality with underlying diseases and for any impact that these tests may have on the safety of the procedure. Only tests performed at our institution were analyzed. All instances of any hospital/physician visit related to the procedure were recorded.

A low hemoglobin, hematocrit and platelet count was seen in 3.5%, 1.8% and 0.1% of patients, respectively. These were marginally outside the reference range and not sufficiently abnormal to indicate underlying disease or to affect the procedure. An elevated prothrombin time/international normalized ratio was seen in 4.5% of patients and this was associated with warfarin use (p<0.0001). About 15% of the patients had a disturbance in renal function. An elevated creatinine was associated with diabetes (OR 3.2, 95% CI 1.8 to 5.7, p=0.0001) and hypertension (OR 4.4, 95% CI 2.1 to 9.2, p<0.0001). Cerebral angiography was performed on these patients with appropriate renal protective measures and no cases of acute renal failure secondary to contrast administration were documented.

The incidence of abnormal testing in patients undergoing outpatient cerebral angiography is very low. These results and evidence in the literature suggest that the majority of patients undergoing cerebral angiography do not require any pre-procedure testing. Assessment of renal function using the estimated glomerular filtration rate in high-risk patients only is, however, warranted.