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Impaired coronary flow reserve in hemodialysis patients: a transthoracic Doppler echocardiographic study
Derya Tok1, Hakan Gullu, Dogan Erdogan
1Department of Cardiology, Baskent University, Konya Medical and Research Center, Konya, Turkey.
Insights
Coronary flow reserve (CFR) is reduced in hemodialysis patients with normal coronary arteries, indicating early microvascular impairment. This transthoracic echocardiography finding may signal developing uremic myocardial disease.
Area of Science:
- Cardiology
- Nephrology
- Medical Imaging
Background:
- Coronary flow reserve (CFR) assesses the heart's microcirculation's ability to meet increased demand.
- Hemodialysis patients often have normal coronary arteries on angiography but may experience microvascular dysfunction.
- Transthoracic second harmonic Doppler echocardiography is a non-invasive tool for evaluating CFR.
Purpose of the Study:
- To evaluate coronary flow reserve (CFR) in hemodialysis patients with angiographically normal coronary arteries.
- To compare CFR between hemodialysis patients and matched hypertensive controls.
- To determine if reduced CFR is an early indicator of coronary microvascular impairment in chronic renal failure.
Main Methods:
- Transthoracic second harmonic Doppler echocardiography was used to measure coronary basal and hyperemic peak flow velocities after dipyridamole infusion.
- Coronary flow reserve (CFR) was calculated as the ratio of hyperemic to basal diastolic peak velocities.
- Doppler tissue imaging was also performed, and CFR < 2.0 was considered abnormal.
Main Results:
- Hemodialysis patients exhibited significantly lower CFR (2.03 +/- 0.3) compared to controls (2.61 +/- 0.5, p = 0.005).
- Fifty percent of hemodialysis patients had reduced CFR (< 2.0), while only 5% of controls did.
- These findings suggest impaired coronary microvascular function in hemodialysis patients.
Conclusions:
- Impaired coronary microvasculature appears early in patients with chronic renal failure.
- Reduced CFR in hemodialysis patients with normal coronary arteries may precede the development of uremic myocardial disease.
- Transthoracic echocardiography-derived CFR is a potential early marker for coronary vasculature affection in chronic renal failure.
Background:
Coronary flow reserve (CFR) reflects the functional capacity of microcirculation to adapt to blood demand during increased cardiac work. In this study, CFR of hemodialysis patients with angiographically normal coronary arteries was evaluated using transthoracic second harmonic Doppler echocardiography.
Methods And Results:
Ten hemodialysis patients, and 14 sex-, age- and left ventricular mass index-matched hypertensive controls with angiographically normal coronary arteries underwent transthoracic second harmonic Doppler echocardiographic examination. Coronary basal diastolic peak flow velocities and hyperemic peak flow velocities after dipyridamole infusion (0.56 mg/kg over 4 min) were measured. CFR was defined as the ratio of hyperemic to basal diastolic peak velocities. CFR > or =2.0 was regarded as normal. Additionally, Doppler tissue imaging pulse wave measurements were taken from the lateral and septal corners of the mitral annulus. CFR values were significantly lower in the study group than in the control group (2.03 +/- 0.3 vs. 2.61 +/- 0.5, p = 0.005). In 5 of 10 hemodialysis patients, CFR was <2.0 (50%), however in only 1 of 14 control patients it was <2.0 (5%).
Conclusions:
Impairment of coronary microvasculature occurs earlier in patients with chronic renal failure and may be the harbinger of subsequent primary uremic myocardial disease. In patients with chronic renal failure and normal coronary arteries, decreased CFR by transthoracic echocardiography might be regarded as an early finding of an affected coronary vasculature.
