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Impact of calcium antagonists on bleeding time in patients with chronic renal failure
K Hayashi1, H Matsuda, M Honda
1Department of Internal Medicine, School of Medicine, Keio University, Tokyo, Japan. khayashi@mc.med.keio.ac.jp
Insights
Calcium antagonists prolong bleeding time in patients with chronic renal failure. However, this laboratory finding does not typically lead to significant bleeding events.
Area of Science:
- Nephrology
- Hematology
- Pharmacology
Background:
- Chronic renal failure (CRF) is associated with hemorrhagic diathesis.
- Calcium antagonists are commonly prescribed antihypertensives in CRF patients.
- The effect of calcium antagonists on bleeding time in CRF is not well-established.
Purpose of the Study:
- To investigate whether calcium antagonists influence bleeding time in patients with chronic renal failure.
- To correlate bleeding time with renal function parameters and platelet counts.
Main Methods:
- A cohort of 156 patients with CRF was studied.
- Bleeding time was measured using Ivy's method.
- Blood parameters including BUN, creatinine, platelet count, and hemoglobin were analyzed.
Main Results:
- Patients taking calcium antagonists showed a significantly higher incidence of prolonged bleeding time (31/122) compared to those not taking them (3/34).
- A positive correlation was found between bleeding time and BUN in both groups.
- Odds ratio for prolonged bleeding time was 3.52 in patients on calcium antagonists.
- Withdrawal of calcium antagonists shortened bleeding time in treated patients.
Conclusions:
- Calcium antagonists prolong bleeding time in patients with chronic renal failure.
- This subclinical prolongation of bleeding time is not necessarily associated with clinically significant hemorrhagic events.
Abstract:
Haemorrhagic diathesis develops in chronic renal failure, in which calcium antagonists are used widely as antihypertensive agents. Although calcium antagonists are reported to impair platelet function, it has not been examined whether calcium antagonists alter bleeding time. The present study was conducted to clarify whether calcium antagonists affect bleeding time in chronic renal failure. Patients with chronic renal failure without and with calcium antagonists were enrolled (n = 156), and bleeding time (Ivy's method) as well as blood parameters (BUN, creatinine, platelet counts, and haemoglobin) were compared in patients with normal and prolonged bleeding time. Among patients not taking calcium antagonists (n = 34), three cases manifested prolonged bleeding time, whereas abnormal bleeding time was observed in 31 patients out of 122. Positive correlations were observed between bleeding time and BUN in both calcium antagonist-untreated (r = 0.46) and -treated groups (r = 0.25). The odds ratio for prolongation of bleeding time in patients taking calcium antagonists was 3.52 (95% CI, 1.01-12.33). In 12 calcium antagonist-treated patients with prolonged bleeding time, the withdrawal of calcium antagonists markedly shortened bleeding time (from 11.3 +/- 0.8 to 5.4 +/- 0.8 min, P < 0.05, n = 12). In contrast, in the additional group (n = 9), the continued treatment with calcium antagonists had no effect on bleeding time (from 11.7 +/- 0.9 to 10.0 +/- 1.0 min). Despite the inhibitory effect of calcium antagonists on bleeding time, no clinically serious events associated with haemorrhagic diathesis developed. In conclusion, calcium antagonists prolong bleeding time in patients with chronic renal failure. The subclinical (laboratory) effect of calcium antagonists however is not necessarily associated with haemorrhagic events of clinical significance.