Dataset Information

Measurement of pulmonary flow reserve and pulmonary index of microcirculatory resistance for detection of pulmonary microvascular obstruction.

ABSTRACT:

Background

The pulmonary microcirculation is the chief regulatory site for resistance in the pulmonary circuit. Despite pulmonary microvascular dysfunction being implicated in the pathogenesis of several pulmonary vascular conditions, there are currently no techniques for the specific assessment of pulmonary microvascular integrity in humans. Peak hyperemic flow assessment using thermodilution-derived mean transit-time (T(mn)) facilitate accurate coronary microcirculatory evaluation, but remain unvalidated in the lung circulation. Using a high primate model, we aimed to explore the use of T(mn) as a surrogate of pulmonary blood flow for the purpose of measuring the novel indices Pulmonary Flow Reserve [PFR = (maximum hyperemic)/(basal flow)] and Pulmonary Index of Microcirculatory Resistance [PIMR = (maximum hyperemic distal pulmonary artery pressure)x(maximum hyperemic T(mn))]. Ultimately, we aimed to investigate the effect of progressive pulmonary microvascular obstruction on PFR and PIMR.

Methods and results

Temperature- and pressure-sensor guidewires (TPSG) were placed in segmental pulmonary arteries (SPA) of 13 baboons and intravascular temperature measured. T(mn) and hemodynamics were recorded at rest and following intra-SPA administration of the vasodilator agents adenosine (10-400 microg/kg/min) and papaverine (3-24 mg). Temperature did not vary with intra-SPA sensor position (0.010+/-0.009 v 0.010+/-0.009 degrees C; distal v proximal; p = 0.1), supporting T(mn) use in lung for the purpose of hemodynamic indices derivation. Adenosine (to 200 microg/kg/min) & papaverine (to 24 mg) induced dose-dependent flow augmentations (40+/-7% & 35+/-13% T(mn) reductions v baseline, respectively; p<0.0001). PFR and PIMR were then calculated before and after progressive administration of ceramic microspheres into the SPA. Cumulative microsphere doses progressively reduced PFR (1.41+/-0.06, 1.26+/-0.19, 1.17+/-0.07 & 1.01+/-0.03; for 0, 10(4), 10(5) & 10(6) microspheres; p = 0.009) and increased PIMR (5.7+/-0.6, 6.3+/-1.0, 6.8+/-0.6 & 7.6+/-0.6 mmHg.sec; p = 0.0048).

Conclusions

Thermodilution-derived mean transit time can be accurately and reproducibly measured in the pulmonary circulation using TPSG. Mean transit time-derived PFR and PIMR can be assessed using a TPSG and adenosine or papaverine as hyperemic agents. These novel indices detect progressive pulmonary microvascular obstruction and thus have with a potential role for pulmonary microcirculatory assessment in humans.

SUBMITTER: Ilsar R

PROVIDER: S-EPMC2834756 | biostudies-literature | 2010 Mar

REPOSITORIES: biostudies-literature

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Publications

Measurement of pulmonary flow reserve and pulmonary index of microcirculatory resistance for detection of pulmonary microvascular obstruction.

Ilsar Rahn R Chawantanpipat Chirapan C Chan Kim H KH Dobbins Timothy A TA Waugh Richard R Hennessy Annemarie A Celermajer David S DS Ng Martin K C MK

PloS one 20100309 3

<h4>Background</h4>The pulmonary microcirculation is the chief regulatory site for resistance in the pulmonary circuit. Despite pulmonary microvascular dysfunction being implicated in the pathogenesis of several pulmonary vascular conditions, there are currently no techniques for the specific assessment of pulmonary microvascular integrity in humans. Peak hyperemic flow assessment using thermodilution-derived mean transit-time (T(mn)) facilitate accurate coronary microcirculatory evaluation, but ...[more]

PMID: 20231900

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Project description:BackgroundAngio-based index of microcirculatory resistance (IMR) and fractional flow reserve (FFR) have been developed, however, the differences between baseline and hyperemic data and their effects on their computation have not yet been discussed. This study aimed to compare the diagnostic performance of a novel method for calculating IMR and FFR from coronary angiography under baseline and hyperemic conditions.MethodsWe performed a retrospective study to investigate the diagnostic performance of angiography-derived IMR (AccuIMR) and FFR (AccuFFRangio) computed from the hyperemic condition (AccuIMRhyp, AccuFFRangiohyp) and baseline condition (AccuIMRbase, AccuFFRangiobase) in 101 consecutive patients with chronic coronary syndrome (CCS) who underwent measurements of IMR and FFR at a single center, using wire-based IMR and FFR as the reference standard.ResultsAccuIMRhyp showed much better correlation with IMR than AccuIMRbase (r=0.77 vs. 0.47, P<0.001). The diagnostic accuracy and area under the curve (AUC) for identifying significant microvascular dysfunction was higher for AccuIMRhyp than AccuIMRbase [92.1% (95% CI: 85.0-96.5%) vs. 83.2% (95% CI: 74.4-89.9%), P=0.012; 0.942 (95% CI: 0.877-0.979) vs. 0.815 (95% CI: 0.726-0.886), P=0.003]. The computed AccuFFRangio showed good correlations with FFR and good diagnostic performance under both hyperemic and baseline conditions [r=0.68 vs. 0.68, P>0.99; diagnostic accuracy =95.9% (95% CI: 89.8-98.9%) vs. 94.9% (95% CI: 88.4-98.3%), P=0.728; AUC =0.989 (95% CI: 0.942-1.000) vs. 0.973 (95% CI: 0.919-0.995), P=0.381]. The net reclassification index (NRI) demonstrated that hyperemic group had improved reclassification ability compared to the baseline group in identification of IMR >25 (NRI =0.20, P<0.001) and FFR ≤0.8 (NRI =0.11, P<0.001).ConclusionsBy comparing the calculated angio-derived IMR and FFR under the baseline and hyperemic conditions, this study demonstrates that AccuIMR calculation is more accurate using the hyperemic condition, while AccuFFRangio calculation is accurate under both conditions.

Project description:BackgroundThe association between coronary slow flow (CSF) and coronary microvascular dysfunction (CMD) remains unclear. The objective of this study was to evaluate the correlation between the corrected thrombolysis in myocardial infarction (TIMI) frame count (CTFC) and the index of microcirculatory resistance (IMR).MethodsWe consecutively enrolled patients with CSF from January 2017 to March 2018. Concurrently, we randomly selected control participants with normal flow arteries at a ratio of 3:1. Two cardiologists performed the measurements of CTFC. Coronary angiography-derived IMR (caIMR) was used to assess CMD. The caIMR was analyzed by an independent agency, with CMD being defined as caIMR >40 U.ResultsA total of 111 patients with CSF and 39 patients without CSF were enrolled in this retrospective study. Compared with the non-CSF group, the CSF group had a greater proportion of males (65.8% vs. 23.1%; P<0.001) and a lower prevalence of hypertension (47.7% vs. 67.7%; P=0.042). Additionally, the CSF group had higher CTFC, coronary angiography-derived fractional flow reserve (caFFR), and caIMR regardless of left anterior descending artery (LAD), left circumflex artery (LCX), and right coronary artery (RCA) (all P values <0.001). A strong correlation between CTFC and caIMR was observed for all arteries (all P values <0.001). In the univariate analysis, male sex [hazard ratio (HR) =2.63, 95% CI: 1.30-5.31], E/e' (HR =0.88, 95% CI: 0.78-0.99), CTFC (HR =1.12, 95% CI: 1.09-1.16), and caFFR (HR =1.81, 95% CI: 1.50-2.17) were significantly correlated with CMD. After adjusting for covariates, male sex (HR =2.72, 95% CI: 1.22-6.06), CTFC (HR =1.10, 95% CI: 1.07-1.14), and caFFR (HR =1.22, 95% CI: 1.00-1.50) were independent predictors for CMD. Additionally, the best cutoff value of CTFC of all arteries for predicting CMD was 38 frames, with an area under the curve of 0.873, a sensitivity of 92.8%, and a specificity of 63.8% (P<0.001). Moreover, the best cutoff value of CTFC of LAD, LCX, and RCA to identify CMD was 35 frames, 52 frames, and 50 frames, respectively (all P values <0.001).ConclusionsCTFC correlated well with caIMR and had a strong predictive power to identify CMD.

Dataset Information

Measurement of pulmonary flow reserve and pulmonary index of microcirculatory resistance for detection of pulmonary microvascular obstruction.

Background

Methods and results

Conclusions

Publications

Measurement of pulmonary flow reserve and pulmonary index of microcirculatory resistance for detection of pulmonary microvascular obstruction.

Similar Datasets

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