Aspirin resistance in patients with chronic renal failure.

BACKGROUND: Chronic renal failure (CRF) is associated with increased risk of cardiovascular morbidity and mortality. Aspirin resistance worsens clinical prognosis. The aim of this study was to explore the prevalence of aspirin resistance in CRF. METHODS: Two hundred and forty-five CRF patients (115 patients undergoing chronic hemodialysis and 130 patients with stage 3-4 chronic kidney disease [CKD]) and 130 patients with normal renal functions (control group) were consecutively recruited. All subjects were taking aspirin regularly. Aspirin responsiveness was determined by Ultegra Rapid Platelet Function Assay-ASA (VerifyNow Aspirin). Aspirin resistance was defined as aspirin reaction unit (ARU) =550. RESULTS: Aspirin resistance was detected in 53 patients undergoing hemodialysis, 32 patients with stage 3-4 CKD and 22 controls. The frequency of aspirin resistance was significantly higher in the CRF group compared with controls (34.7% vs. 16.9%, p<0.001) and in hemodialysis patients (46.1%) compared with stage 3-4 CKD patients (24.6%, p<0.001) and controls (16.9%, p<0.001). Multivariate analysis revealed female sex (odds ratio [OR] = 2.201; 95% confidence interval [95% CI], 1.173-4.129; p=0.014), hemodialysis (OR=3.636; 95%CI, 1.313-10.066; p=0.013) and HDL cholesterol (OR=0.974; 95% CI, 0.950-0.999; p=0.043) as independent predictors of aspirin resistance in this cohort of patients. CONCLUSION: Patients with CRF have higher frequency of aspirin resistance. This might further increase the risk of cardiovascular morbidity and mortality in these patients.

Aspirin resistance in hypertensive patients.

Aspirin resistance is associated with poor clinical prognosis. The authors investigated aspirin resistance in 200 hypertensive patients (111 men, age: 68.3±11.4 years) by the Ultegra Rapid Platelet Function Assay-ASA (Accumetrics Inc., San Diego, CA). Aspirin resistance was defined as an aspirin reaction unit ≥550. Aspirin resistance was detected in 42 patients. Aspirin resistance was present in 25.6% of the patients with poor blood pressure control, while in 17.8% of the patients with controlled blood pressure (P=.182). Female gender and creatinine levels were significantly higher (P=.028 and P=.030, respectively), while platelet count was significantly lower (P=.007) in aspirin-resistant patients. Multivariate analysis revealed that female gender (odds ratio [OR], 2.445; P=.045), creatinine levels (OR, 1.297; P=.015) and platelet count (OR, 0.993; P=.005) were independent predictors of aspirin resistance. The frequency of aspirin resistance is not low in hypertensive patients. Female hypertensive patients, especially, with higher creatinine levels and lower platelet count are at higher risk for aspirin resistance.

Fever-induced precordial ST-segment elevation in a young man.

Brugada syndrome is a rare condition characterized by ST-segment elevation in the right precordial leads. Fever can induce Brugada-like electrocardiographic (ECG) changes. We reported on a 26-year-old male patient with fever and ST-segment elevation in the right precordial leads. Serial cardiac markers were normal and transthoracic echocardiography showed normal wall motion and no evidence for pericardial effusion. Brugada-like ECG changes disappeared after fever resolved. Since the patient had never experienced any arrhythmic symptom, syncope, or spontaneous type 1 ECG, electrophysiological study was not performed and he was not referred for defibrillator implantation. The patient was discharged with strong recommendations to avoid certain medications responsible for Brugada-like ECG changes and to receive urgent treatment for fever. He was asymptomatic during a year follow-up. Emphasis is placed on this particularly rare, but important condition, as it may easily be misdiagnosed and fever may even precipitate ventricular fibrillation.