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Assessment of angiographically intermediate coronary artery stenosis using the Doppler flowire
M J Kern1, T J Donohue, F V Aguirre
1Cardiology Division, St. Louis University Hospital, Missouri 63110.
Insights
Spectral flow velocity measurements using Doppler guidewires offer a more accurate assessment of coronary stenosis significance than angiography. This technique correlates well with pressure gradients, improving clinical decision-making for coronary artery disease.
Area of Science:
- Cardiology
- Interventional Cardiology
- Physiology
Background:
- Assessing the clinical significance of coronary stenoses is challenging.
- Angiography and coronary vasodilator reserve are imperfect tools for determining physiologic significance.
Purpose of the Study:
- To compare spectral flow velocity data with translesional pressure gradients and angiography.
- To evaluate the utility of Doppler-tipped guidewires in assessing coronary stenosis severity.
Main Methods:
- Intracoronary Doppler-tipped guidewire used to measure spectral flow velocity proximal and distal to stenoses.
- Comparison of flow velocity data with translesional pressure gradients and quantitative angiography.
- Patients grouped by resting translesional gradients (<20 mm Hg vs. ≥20 mm Hg).
Main Results:
- Flow velocity integrals were significantly lower in patients with lower pressure gradients.
- Patients with gradients ≥20 mm Hg showed significantly decreased distal flow velocities (p < 0.01).
- Proximal-to-distal total flow velocity integral ratios strongly correlated with pressure gradients (r = 0.8, p < 0.001).
- Angiography poorly predicted gradients in intermediate stenoses (50-70%), while flow velocity ratios remained strongly correlated (r = 0.8, p < 0.0001).
Conclusions:
- Spectral flow velocity assessment using Doppler guidewires is superior to angiography for determining the hemodynamic significance of coronary stenoses.
- Flow velocity ratios provide a reliable measure of stenosis severity, correlating strongly with pressure gradients.
Abstract:
Determination of the clinical and hemodynamic significance of coronary stenoses is often difficult and inexact. Angiography and coronary vasodilator reserve have been shown to be imperfect tools to determine the physiologic significance of coronary stenoses. Spectral flow velocity data, both proximal and distal to coronary stenoses, using an 0.018-in intracoronary Doppler-tipped angioplasty guidewire, were compared to translesional pressure gradients and angiography during cardiac catheterization. Patients were divided into 2 groups based on resting translesional gradients: Group 1 had gradients < 20 mm Hg and group 2 had gradients > or = 20 mm Hg. Proximal average peak velocity, diastolic velocity integral, and total velocity integral were statistically significantly lower in Group 1. The distal average peak velocity, and diastolic and total velocity integrals were all significantly (p < 0.01) decreased in patients with gradients > 20 mm Hg (group 2). The ratio of proximal-to-distal total flow velocity integral was also higher in group 2 patients (2.3 +/- 0.9) compared with group 1 (1.1 +/- 0.2; p < 0.001). There was a strong correlation between translesional pressure gradients and the ratios of the proximal-to-distal total flow velocity integrals (r = 0.8, p < 0.001) with a weaker relationship between quantitative angiography and pressure gradients (r = 0.6, p < 0.001). Angiography was a poor predictor of translesional gradients in angiographically intermediate stenoses (range 50-70%; r = 0.2, p = NS), while the flow velocity ratios continued to have a strong correlation (r = 0.8, p < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)