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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.


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Distribution of the coronary arteries measured stratified according to percentage of diameter stenosis % (upper panel) and fractional flow reserve (lower panel).
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EHV626F2: Distribution of the coronary arteries measured stratified according to percentage of diameter stenosis % (upper panel) and fractional flow reserve (lower panel).

Mentions: The distribution of stenoses was consistent with that typically found in clinical practice with mean FFR 0.81 ± 0.16 and mean QCA diameter stenosis of 48.5 ± 25.2%, indicating that the majority was of intermediate severity (Figure 2). In the 201 reference vessels, FFR ranged from 0.85 to 1.08 with a mean FFR of 0.96 ± 0.04. Overall, these findings confirmed the absence of obstructive epicardial disease. In 23 (11%) of the reference cases, an FFR of >0.80 and ≤0.90 was documented, suggesting the existence of abnormal epicardial conductance. A value of FFR > 1.0 was noted in 30 vessels despite careful drift assessment. This predominantly occurred in the LCx (18 cases, 60%) and in reference vessels (26 cases, 87%) and was likely due to hydrostatic consequences of the wire being in a distal vessel below the position of the transducer. For the stenosed vessels, the relationship between FFR and anatomical DS% demonstrated significant scatter (R2 = 0.23, P < 0.01; Figure 3). Similar findings were noted when plotting FFR and anatomical minimal luminal diameter (R2 = 0.19, P < 0.001; Supplementary material online, Figure S1).Figure 2


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
Distribution of the coronary arteries measured stratified according to percentage of diameter stenosis % (upper panel) and fractional flow reserve (lower panel).
© Copyright Policy - creative-commons
Related In: Results  -  Collection

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

EHV626F2: Distribution of the coronary arteries measured stratified according to percentage of diameter stenosis % (upper panel) and fractional flow reserve (lower panel).
Mentions: The distribution of stenoses was consistent with that typically found in clinical practice with mean FFR 0.81 ± 0.16 and mean QCA diameter stenosis of 48.5 ± 25.2%, indicating that the majority was of intermediate severity (Figure 2). In the 201 reference vessels, FFR ranged from 0.85 to 1.08 with a mean FFR of 0.96 ± 0.04. Overall, these findings confirmed the absence of obstructive epicardial disease. In 23 (11%) of the reference cases, an FFR of >0.80 and ≤0.90 was documented, suggesting the existence of abnormal epicardial conductance. A value of FFR > 1.0 was noted in 30 vessels despite careful drift assessment. This predominantly occurred in the LCx (18 cases, 60%) and in reference vessels (26 cases, 87%) and was likely due to hydrostatic consequences of the wire being in a distal vessel below the position of the transducer. For the stenosed vessels, the relationship between FFR and anatomical DS% demonstrated significant scatter (R2 = 0.23, P < 0.01; Figure 3). Similar findings were noted when plotting FFR and anatomical minimal luminal diameter (R2 = 0.19, P < 0.001; Supplementary material online, Figure S1).Figure 2

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 &le; 0.50, hyperaemic flow falls significantly from 45 to 19 cm/s, Ptrend &lt; 0.001 in a curvilinear pattern. Resting flow was unaffected by stenosis severity and was consistent across all strata of stenosis (Ptrend &gt; 0.05 for all). Trans-stenotic pressure gradient rose with stenosis severity for both rest and hyperaemic measures (Ptrend &lt; 0.001 for both). Microvascular resistance declines with stenosis severity under resting conditions (Ptrend &lt; 0.001), but was unchanged at hyperaemia (2.3 &plusmn; 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