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Vasodilatory capacity of coronary resistance vessels in dilated cardiomyopathy
1Department of Cardiology, Koshigaya Hospital, Dokkyo University School of Medicine, Saitama, Japan.
Insights
Dilated cardiomyopathy (DCM) patients show impaired coronary vasodilation, affecting both endothelium-dependent and independent responses. This suggests endothelial dysfunction and left ventricular dysfunction contribute to reduced coronary blood flow in DCM.
Area of Science:
- Cardiology
- Vascular Biology
- Heart Failure Research
Background:
- Dilated cardiomyopathy (DCM) is a significant cause of heart failure.
- Coronary vascular function plays a crucial role in maintaining myocardial health.
- Understanding vasodilatory capacity in DCM is essential for therapeutic strategies.
Purpose of the Study:
- To investigate endothelium-dependent and endothelium-independent vasodilation in coronary resistance vessels of DCM patients.
- To correlate coronary vasodilation with hemodynamic parameters in DCM.
Main Methods:
- Utilized a 3F coronary Doppler catheter in the left anterior descending artery.
- Administered intracoronary papaverine (endothelium-independent vasodilator) and acetylcholine (endothelium-dependent vasodilator).
- Measured coronary blood flow velocity ratios (Vp/Vo and Va/Vo) and correlated with left ventricular parameters.
Main Results:
- DCM patients exhibited significantly diminished Vp/Vo (2.2 +/- 0.6 vs 4.1 +/- 0.9) and Va/Vo (1.3 +/- 0.5 vs 2.4 +/- 0.8) compared to controls.
- Vp/Vo in DCM correlated with left ventricular end-diastolic pressure, volume index, ejection fraction, and wall stress.
- Va/Vo did not correlate with these left ventricular parameters.
Conclusions:
- Coronary resistance vessel vasodilation is impaired in DCM.
- Endothelial dysfunction and extravascular factors related to left ventricular dysfunction likely contribute to impaired vasodilation in DCM.
Abstract:
Both the endothelium-dependent and endothelium-independent vasodilatory responses of coronary resistance vessels were studied in patients with dilated cardiomyopathy (DCM). A 3F coronary Doppler catheter was placed in the proximal left anterior descending artery in 14 patients with DCM and in 10 patients with chest pain syndrome and a normal heart (control subjects). The ratio of maximum mean coronary blood flow velocity after intracoronary administration of the endothelium-independent vasodilator papaverine (10 mg) to resting mean coronary blood flow velocity (Vp/Vo) in patients with DCM was diminished compared with that in control subjects (2.2 +/- 0.6 vs 4.1 +/- 0.9, p < 0.001). The ratio after administration of the endothelium-dependent vasodilator acetylcholine (40 micrograms) (Va/Vo) in 10 DCM patients was also diminished compared with that in seven control subjects (1.3 +/- 0.5 vs 2.4 +/- 0.8, p < 0.01). In DCM patients, Vp/Vo was correlated with left ventricular end-diastolic pressure (r = -0.48, p < 0.05), left ventricular end-diastolic volume index (r = -0.68, p < 0.01), ejection fraction (r = 0.75, p < 0.01), and left ventricular end-diastolic wall stress (r = -0.73, p < 0.01). However, Va/Vo was not correlated with any of these parameters. These results indicate that impairment of the vasodilatory capacity of coronary resistance vessels in DCM may be related to endothelial dysfunction and to an extravascular factor resulting from left ventricular dysfunction.