Calcium Antagonists for Secondary Prevention of Myocardial Infarction Is There a Need to Shift From Short-Acting to Long-Acting Types?

Impact of Long-Acting Calcium Channel Blockers on the Prognosis of Patients with Coronary Artery Disease with and without Chronic Kidney Disease: A Comparison of Three Drugs

Calcium channel blockers (CCBs) can prevent cardiovascular events in patients with coronary artery disease (CAD). This study looked retrospectively at the prognosis of CAD in hypertensive patients with CAD who had undergone a coronary angiograph, had been given a CCB (benidipine [ n = 66], amlodipine [ n = 45], or long-acting nifedipine [ n = 31]) on hospital discharge and were then followed up for a mean ± SD of 5.2 ± 2.9 years. Systolic/diastolic blood pressure for all 142 patients decreased significantly from a mean ± SD of 137 ± 20/74 ± 15 mmHg to 129 ± 20/71 ± 12 mmHg. Major adverse cardiovascular events (MACE) occurred in 15 patients. Chronic kidney disease (CKD) was a significant risk factor for MACE (hazard ratio 2.35, 95% confidence intervals 1.45, 3.80). Benidipine was superior to nifedipine in preventing MACE in patients both with and without CKD. In conclusion, benidipine and amlodipine reduced the frequency of MACE in hypertensive patients with CAD, particularly in those with complicating CKD.

Cross-bridge-dependent change in Ca2+ sensitivity is involved in the negative inotropic effect of nifedipine in aequorin-injected ferret ventricular muscles

BACKGROUND

We hypothesized that the negative inotropic effect of nifedipine (Nif) on cardiac ventricular muscle is partly due to the cross-bridge-dependent decrease of Ca2+ sensitivity of the myofilaments as well as the decrease in Ca2+ influx.

METHOD AND RESULTS

We used aequorin-injected ferret papillary muscles and measured the slope of the extra-Ca(2+)-tension relation which expresses the change in the Ca2+ sensitivity through the feedback from the cross-bridges. Twitch tension was decreased significantly by 0.5 micromol/L Nif accompanying a significant reduction of the Ca2+ transient peak. When Nif (0.2-0.5 micromol/L) was added to the solution with 8 mmol/L Ca2+, the slope of the extra-Ca2+-tension relation became steeper in a concentration-dependent manner, which was similar to the change in the slope when the concentration of Ca2+ was decreased from 8 to 1 mmol/L in the absence of Nif. BAY-K 8644 (0.3 micromol/L), a dihydropyridine receptor agonist, showed the opposite effect on the slope of the extra-Ca2+-tension relation to that observed in Nif. However, 2,3-butanedione monoxime (3 mmol/L), an inhibitor of the active cross-bridges, antagonized the effect of BAY-K 8644.

CONCLUSION

Nif exerts its negative inotropic effect on cardiac muscle by suppressing Ca2+ binding to troponin C via the inhibition of the L-type Ca2+ channel, and by the cross-bridge-dependent decrease in the Ca2+ sensitivity, as in low extracellular Ca2+ concentration.