Secondary Stroke Prevention: A Population-Based Cohort Study on Anticoagulation and Antiplatelet Treatments, and the Risk of Death or Recurrence

Using claims databases of a public healthcare program (Quebec) for the years 2010-2013, we conducted a cohort study of patients with acute ischemic stroke (AIS) to describe secondary prevention treatments and determine how they stood against practice guidelines. We compared the risk of death or AIS recurrence over 1 year in patients treated with anticoagulants, antiplatelets, and/or other cardiovascular drugs. In the month after discharge, 44.3% of the patients did not receive the recommended treatment and > 20% did not have any treatment. Untreated patients were younger, had less comorbidities, and a more severe AIS. Anticoagulants and antiplatelets were associated with a reduced risk of death or recurrence (hazard ratio (HR) 0.27; 95% confidence interval (CI) 0.20-0.36 and HR 0.25; 95% CI 0.16-0.38, respectively) compared with the untreated group. Effect size was similar for the other treatments. Findings confirm treatment benefits shown in clinical trials and emphasize the importance of AIS secondary prevention.

Immediate Hypersensitivity to Contrast Agents: The French 5-year CIRTACI Study

BACKGROUND

Iodinated and gadolinium-based contrast media (ICM; GBCM) induce immediate hypersensitivity (IH) reactions. Differentiating allergic from non-allergic IH is crucial; allergy contraindicates the culprit agent for life. We studied frequency of allergic IH among ICM or GBCM reactors.

METHODS

Patients were recruited in 31 hospitals between 2005 and 2009. Clinical symptoms, plasma histamine and tryptase concentrations and skin tests were recorded. Allergic IH was diagnosed by intradermal tests (IDT) with the culprit CM diluted 1:10, "potentially allergic" IH by positive IDT with pure CM, and non-allergic IH by negative IDT.

FINDINGS

Among 245 skin-tested patients (ICM = 209; GBCM = 36), allergic IH to ICM was identified in 41 (19.6%) and to GBCM in 10 (27.8%). Skin cross-reactivity was observed in 11 patients with ICM (26.8%) and 5 with GBCM (50%). Allergy frequency increased with clinical severity and histamine and tryptase concentrations (p < 0.0001). Cardiovascular signs were strongly associated with allergy. Non-allergic IH was observed in 152 patients (62%) (ICM:134; GBCM:18). Severity grade was lower (p < 0.0001) and reaction delay longer (11.6 vs 5.6 min; p < 0.001). Potentially allergic IH was diagnosed in 42 patients (17.1%) (ICM:34; GBCM:8). The delay, severity grade, and mediator release were intermediate between the two other groups.

INTERPRETATION

Allergic IH accounted for < 10% of cutaneous reactions, and > 50% of life-threatening ones. GBCM and ICM triggered comparable IH reactions in frequency and severity. Cross-reactivity was frequent, especially for GBCM. We propose considering skin testing with pure contrast agent, as it is more sensitive than the usual 1:10 dilution criteria.