Diabetic Retinopathy and Thrombolysis
Source: Mahaffey KW, et al. J Am Coll Cardiol 1997; 30:1606-1610.
Diabetic retinopathy has been at least a relative contraindication to thrombolytic therapy because of reports of intraocular hemorrhage. Since diabetics frequently have coronary events, Mahaffey and colleagues evaluated their database on this issue by reviewing all cases of suspected ocular hemorrhage. Diabetes or its complications were not an exclusion criteria in this trial that compared four t-PA, streptokinase, and heparin strategies. Of the 40,899 patients with information available, 12 had ocular hemorrhage (0.03%), 11 were extraocular, and one was intraocular (subretinal) for a rate of 0.002%. Of the 5995 patients with diabetes (15% of the total population), only one had an extraocular hemorrhage (eyelid hematoma) after a fall. Mahaffey et al conclude that ocular hemorrhage after thrombolytic therapy is rare, and diabetic retinopathy should not be considered a contraindication to this treatment for acute MI.These observational data are of importance because of the high number of patients involved and the very low incidence of intraocular hemorrhage. It does not directly answer the question of what is the risk of intraocular hemorrhage with thrombolytic therapy in diabetic patients with retinopathy, however, because no systematic attempt was made in the trial to identify such patients. The accurate diagnosis of diabetic retinopathy requires pupil dilatation and skilled fundoscopy, which is usually not feasible in the setting of an acute MI. Based upon other data, at least 2000 of the GUSTO-1 patients would be expected to have diabetic retinopathy, and not one had an intraocular hemorrhage. These results are consistent with other smaller trials, which prompted Mahaffey et al of the most recent ACC/AHA guidelines on the treatment of acute MI not to include diabetic retinopathy as a contraindication to thrombolytic therapy. On the other hand, the physician still needs to use good clinical judgment. A patient with recent eye surgery or hemorrhagic ocular event would have to be considered a relative contraindication to be weighed with other characteristics of the patient who might favor another therapeutic approach (i.e., primary angioplasty). Mahaffey et al estimate that the actual risk of intraocular hemorrhage in a diabetic patient could be as high as 0.05% based upon the 95% confidence intervals around their observed incidence of 0.002%. However, keep in mind that these estimates are based upon one observed event. —mhc
Absolute contraindications to thrombolytic therapy include all of the following except:
a. recent stroke.
b. active GI bleeding.
c. diabetic retinopathy.
d. malignant hypertension.
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