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Coronary flow dynamics and reserve assessed by transesophageal echocardiography in obstructive hypertrophic
C Memmola1, S Iliceto, V F Napoli
1Institute of Cardiology, University of Bari, Italy.
Insights
Obstructive hypertrophic cardiomyopathy (HC) significantly alters coronary flow dynamics. Transesophageal echo-Doppler revealed impaired coronary flow reserve (CFR) and abnormal coronary flow velocity (CFV) patterns in HC patients, correlating with pressure gradients.
Area of Science:
- Cardiology
- Medical Imaging
- Physiology
Background:
- Myocardial ischemia is often linked to left ventricular outflow obstruction.
- Obstructive hypertrophic cardiomyopathy (HC) presents a unique challenge in assessing coronary circulation.
Purpose of the Study:
- To evaluate coronary flow dynamics and coronary flow reserve (CFR) in patients with obstructive HC using transesophageal echo-Doppler.
- To compare coronary flow velocity (CFV) patterns and CFR between obstructive HC patients and healthy controls.
Main Methods:
- Transesophageal echo-Doppler assessment of resting CFV in the left anterior descending coronary artery.
- Evaluation of CFR using dipyridamole infusion response.
- Comparison between 10 obstructive HC patients and 10 healthy controls.
Main Results:
- Patients with HC exhibited a significantly increased diastolic/systolic CFV ratio at rest and after dipyridamole infusion.
- A significantly reduced CFR was observed in HC patients compared to controls.
- A significant correlation was found between CFR and intraventricular pressure gradient.
Conclusions:
- Transesophageal echo-Doppler is effective in characterizing abnormal coronary flow dynamics and impaired CFR in obstructive HC.
- Findings highlight the utility of echo-Doppler in assessing coronary microvascular function in HC.
Abstract:
Myocardial ischemia is frequently associated with left ventricular outflow obstruction. To assess coronary flow impairment in obstructive hypertrophic cardiomyopathy (HC), 10 patients with echo-Doppler-detected obstructive HC and normal coronary arteries underwent transesophageal echo-Doppler examination of both coronary flow velocity (CFV) at rest, recorded in the proximal left anterior descending coronary artery, and coronary flow reserve (CFR) evaluated by means of dipyridamole infusion response. Ten normal patients were similarly studied and served as a control group. Two relevant alterations in coronary flow dynamics were detected in patients with HC: (1) a significantly increased diastolic/systolic CFV ratio, and (2) a significantly reduced dipyridamole/baseline CFV ratio. Compared with normal subjects, the CFV pattern showed a significantly greater diastolic and a significantly lower systolic component at rest (in some patients it was reversed). Diastolic/systolic CFV ratio was significantly higher in patients with HC at baseline (3.1 +/- 1 vs 1.6 +/- 0.5; p < 0.01) and increased further after dipyridamole infusion (4.9 +/- 2 vs 2.2 +/- 0.7; p < 0.01). In addition, CFR was impaired in patients with HC (1.8 +/- 0.3 vs 3.1 +/- 0.5; p < 0.01). Furthermore, a significant correlation between CFR and intraventricular pressure gradient was found. Thus, transesophageal echo-Doppler examination is a useful tool for evaluating CFV dynamics and CFR as demonstrated in patients with obstructive HC.