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Increase in plasma digitalis-like activity during percutaneous transluminal coronary angioplasty in patients with
P Delva1, E Barbieri, M A Devynck
1Department of Clinical Medicine, University of Verona, Italy.
Insights
Plasma from patients showed increased digitalis-like factor after percutaneous transluminal coronary angioplasty (PTCA). This suggests a potential compensatory mechanism in heart disease, impacting Na-K ATPase activity.
Area of Science:
- Cardiology
- Biochemistry
- Physiology
Background:
- The presence of an endogenous digitalis-like factor in plasma is known in essential hypertension.
- Limited data exists on this factor in general heart disease, particularly in low cardiac output states.
- Percutaneous transluminal coronary angioplasty (PTCA) can transiently affect cardiac output and pressures.
Purpose of the Study:
- To investigate the levels of a digitalis-like factor in plasma of patients with coronary artery disease.
- To assess changes in this factor before and after percutaneous transluminal coronary angioplasty (PTCA).
- To evaluate the impact on Na-K ATPase activity and intraerythrocyte electrolyte concentrations.
Main Methods:
- Plasma was collected from the femoral vein of 6 patients with angina pectoris and severe coronary stenosis.
- Measurements were taken before and immediately after percutaneous transluminal coronary angioplasty (PTCA).
- Assayed plasma's ability to inhibit human renal Na(+)-K+ ATPase and measured intraerythrocyte sodium and potassium.
Main Results:
- Significantly greater inhibition of Na(+)-K+ ATPase was observed after PTCA compared to basal levels (31.5% vs 16.1%).
- No significant alterations in intraerythrocyte sodium and potassium concentrations were detected post-PTCA.
- The study indicates an increase in the digitalis-like factor following the procedure.
Conclusions:
- Percutaneous transluminal coronary angioplasty (PTCA) leads to a significant increase in plasma digitalis-like factor.
- The mechanism remains unclear, but a rise in cardiac pressures due to reduced cardiac output may stimulate its production.
- This factor might play a compensatory inotropic role in the context of heart disease and procedural interventions.
Abstract:
Despite the fact that numerous studies have been published regarding the possible presence in plasma of an endogenous Na-K pump inhibitor with a digitalis-like structure in essential hypertension, very little is known about this factor in heart disease in general, and in situations characterized by low cardiac output. We measured the ability of plasma obtained from the femoral vein to inhibit a human renal Na(+)-K+ ATPase before and immediately after percutaneous transluminal coronary angioplasty (PTCA) in 6 patients suffering from angina pectoris and severe coronary stenosis. Intraerythrocyte sodium and potassium concentrations were also measured simultaneously. Na(+)-K+ ATPase inhibition proved significantly greater after angioplasty as compared to basal activity (percentage inhibition: 31.5 +/- 7.8 vs 16.1 +/- 12.2). No significant changes in intraerythrocyte sodium and potassium were detected. Though we are not in a position to define the mechanism underlying the increase in the digitalis-like factor, a plausible hypothesis may be that the reduction in cardiac output during PTCA by raising cardiac pressures may stimulate the production of a factor of compensatory inotropic significance.