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Internal mammary artery graft function is not affected in hypertensive patients on therapy
1II Cardiac Surgery Department, Silesian School of Medicine, Katowice, Poland.
Insights
Human internal mammary artery reactivity is preserved in hypertensive patients on ACE inhibitors or nifedipine. Proper antihypertensive treatment is essential for maintaining graft function, especially endothelial function.
Area of Science:
- Vascular Biology
- Cardiovascular Pharmacology
- Hypertension Research
Background:
- Internal mammary artery (IMA) is a common arterial graft in coronary artery bypass grafting (CABG).
- Hypertension can affect vascular function, potentially impacting graft patency and patient outcomes.
- The effects of specific antihypertensive treatments on IMA reactivity require detailed investigation.
Purpose of the Study:
- To assess the in vitro reactivity of human IMA from non-hypertensive and treated hypertensive patients.
- To compare the responses to vasoconstrictors (KCl, norepinephrine) and a vasodilator (acetylcholine) across different patient groups.
- To evaluate the influence of nitric oxide synthase inhibition on norepinephrine-induced responses.
Main Methods:
- Isolated human IMA segments from three groups: normotensive, hypertensive on ACE inhibitors, and hypertensive on nifedipine.
- In vitro assessment of contractile responses to KCl and norepinephrine.
- Evaluation of relaxation responses to acetylcholine and the effect of N(G)-monomethyl-L-arginine (L-NMMA) on norepinephrine-induced contractions.
Main Results:
- Highest response to KCl observed in the nifedipine-treated group (Group III).
- Contractile reactivity to norepinephrine was reduced in the ACE inhibitor-treated group (Group II).
- Acetylcholine-induced relaxation was enhanced in both treated hypertensive groups (II and III); L-NMMA sensitized the tissue to norepinephrine, with greater sensitization in Group II.
Conclusions:
- IMA function, including endothelial function, is not detrimentally affected by arterial hypertension when appropriately treated.
- Specific antihypertensive medications (ACE inhibitors, nifedipine) modulate IMA reactivity.
- Maintaining proper antihypertensive treatment is crucial for preserving IMA graft function.
Abstract:
Results are presented which assess the reactivity of isolated human internal mammary artery fragments from non-hypertensive and treated hypertensive patients in vitro. Material from three patient groups was examined: group I, no hypertension; group II, arterial hypertension treated with ACE inhibitors; and group III, arterial hypertension treated with nifedipine. Responses to KCl, norepinephrine and acetylcholine, as well as the influence of N(G)-monomethyl-L-arginine (L-NMMA) on the effects of norepinephrine were tested. Response to KCl was highest in group III, while the contractile reactivity to norepinephrine was depressed in group II. Relaxation after acetylcholine was enhanced in groups II and III. Incubation of vessel fragments with L-NMMA sensitized the tissue to norepinephrine in the order of potency group II>group III>group I. Internal mammary artery function as the graft, and particularly in terms of endothelial function, is not adversely affected in arterial hypertension, although proper antihypertensive treatment may be essential.