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Coronary pressure and flow relationships in humans: phasic analysis of normal and pathological vessels and the implications for stenosis assessment: a report from the Iberian – Dutch – English (IDEAL) collaborators

View Article: PubMed Central - PubMed

ABSTRACT

Background: Our understanding of human coronary physiological behaviour is derived from animal models. We sought to describe physiological behaviour across a large collection of invasive pressure and flow velocity measurements, to provide a better understanding of the relationships between these physiological parameters and to evaluate the rationale for resting stenosis assessment.

Methods and results: Five hundred and sixty-seven simultaneous intracoronary pressure and flow velocity assessments from 301 patients were analysed for coronary flow velocity, trans-stenotic pressure gradient (TG), and microvascular resistance (MVR). Measurements were made during baseline and hyperaemic conditions. The whole cardiac cycle and the diastolic wave-free period were assessed. Stenoses were assessed according to fractional flow reserve (FFR) and quantitative coronary angiography DS%. With progressive worsening of stenoses, from unobstructed angiographic normal vessels to those with FFR ≤ 0.50, hyperaemic flow falls significantly from 45 to 19 cm/s, Ptrend < 0.001 in a curvilinear pattern. Resting flow was unaffected by stenosis severity and was consistent across all strata of stenosis (Ptrend > 0.05 for all). Trans-stenotic pressure gradient rose with stenosis severity for both rest and hyperaemic measures (Ptrend < 0.001 for both). Microvascular resistance declines with stenosis severity under resting conditions (Ptrend < 0.001), but was unchanged at hyperaemia (2.3 ± 1.1 mmHg/cm/s; Ptrend = 0.19).

Conclusions: With progressive stenosis severity, TG rises. However, while hyperaemic flow falls significantly, resting coronary flow is maintained by compensatory reduction of MVR, demonstrating coronary auto-regulation. These data support the translation of coronary physiological concepts derived from animals to patients with coronary artery disease and furthermore, suggest that resting pressure indices can be used to detect the haemodynamic significance of coronary artery stenoses.

No MeSH data available.


Related in: MedlinePlus

Top panel: example of simultaneous coronary pressure and flow velocity measurement obtained distal to an left anterior descending stenosis of 69% diameter stenosis by quantitative angiography with FFR of 0.79. Bottom panel: the analysed phases during the resting and hyperaemic state are shown.
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EHV626F1: Top panel: example of simultaneous coronary pressure and flow velocity measurement obtained distal to an left anterior descending stenosis of 69% diameter stenosis by quantitative angiography with FFR of 0.79. Bottom panel: the analysed phases during the resting and hyperaemic state are shown.

Mentions: Flow velocity was assessed over four periods: first, flow velocity at rest over the entire cardiac cycle and secondly over the specific diastolic wave-free period (during which iFR is calculated), which was detected using the ECG signals. Flow velocity was also assessed during adenosine-mediated hyperaemia over the whole cardiac cycle and the wave-free period. The same two time periods in the cardiac cycle, both at rest and hyperaemia, were used to derive measures of microvascular resistance (MVR) and trans-stenotic pressure gradient (TG). Figure 1 shows an example of simultaneous pressure and flow velocity measurements, together with the cardiac phases over which the study parameters were calculated.Figure 1


Coronary pressure and flow relationships in humans: phasic analysis of normal and pathological vessels and the implications for stenosis assessment: a report from the Iberian – Dutch – English (IDEAL) collaborators
Top panel: example of simultaneous coronary pressure and flow velocity measurement obtained distal to an left anterior descending stenosis of 69% diameter stenosis by quantitative angiography with FFR of 0.79. Bottom panel: the analysed phases during the resting and hyperaemic state are shown.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4940452&req=5

EHV626F1: Top panel: example of simultaneous coronary pressure and flow velocity measurement obtained distal to an left anterior descending stenosis of 69% diameter stenosis by quantitative angiography with FFR of 0.79. Bottom panel: the analysed phases during the resting and hyperaemic state are shown.
Mentions: Flow velocity was assessed over four periods: first, flow velocity at rest over the entire cardiac cycle and secondly over the specific diastolic wave-free period (during which iFR is calculated), which was detected using the ECG signals. Flow velocity was also assessed during adenosine-mediated hyperaemia over the whole cardiac cycle and the wave-free period. The same two time periods in the cardiac cycle, both at rest and hyperaemia, were used to derive measures of microvascular resistance (MVR) and trans-stenotic pressure gradient (TG). Figure 1 shows an example of simultaneous pressure and flow velocity measurements, together with the cardiac phases over which the study parameters were calculated.Figure 1

View Article: PubMed Central - PubMed

ABSTRACT

Background: Our understanding of human coronary physiological behaviour is derived from animal models. We sought to describe physiological behaviour across a large collection of invasive pressure and flow velocity measurements, to provide a better understanding of the relationships between these physiological parameters and to evaluate the rationale for resting stenosis assessment.

Methods and results: Five hundred and sixty-seven simultaneous intracoronary pressure and flow velocity assessments from 301 patients were analysed for coronary flow velocity, trans-stenotic pressure gradient (TG), and microvascular resistance (MVR). Measurements were made during baseline and hyperaemic conditions. The whole cardiac cycle and the diastolic wave-free period were assessed. Stenoses were assessed according to fractional flow reserve (FFR) and quantitative coronary angiography DS%. With progressive worsening of stenoses, from unobstructed angiographic normal vessels to those with FFR ≤ 0.50, hyperaemic flow falls significantly from 45 to 19 cm/s, Ptrend < 0.001 in a curvilinear pattern. Resting flow was unaffected by stenosis severity and was consistent across all strata of stenosis (Ptrend > 0.05 for all). Trans-stenotic pressure gradient rose with stenosis severity for both rest and hyperaemic measures (Ptrend < 0.001 for both). Microvascular resistance declines with stenosis severity under resting conditions (Ptrend < 0.001), but was unchanged at hyperaemia (2.3 ± 1.1 mmHg/cm/s; Ptrend = 0.19).

Conclusions: With progressive stenosis severity, TG rises. However, while hyperaemic flow falls significantly, resting coronary flow is maintained by compensatory reduction of MVR, demonstrating coronary auto-regulation. These data support the translation of coronary physiological concepts derived from animals to patients with coronary artery disease and furthermore, suggest that resting pressure indices can be used to detect the haemodynamic significance of coronary artery stenoses.

No MeSH data available.


Related in: MedlinePlus