An interventional study of All participants will undergo cardiopulmonary exercise testing (CPET), transthoracic echocardiography, and invasive coronary angiography with functional microvascular assessment (IMR, cFR, RFR). No in in CMD, Microvascular Dysfunction and Anoca, sponsored by Heart and Diabetes Center North-Rhine Westfalia. Recruiting at 1 site in Germany. Per ClinicalTrials.gov, last updated 2026-11-12.
Sponsored by Heart and Diabetes Center North-Rhine Westfalia · Not applicable, Interventional, and Diagnostic
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Coronary microvascular dysfunction (CMD) has emerged as a key pathophysiological mechanism underlying symptoms in patients with angina and/or exertional dyspnea, particu-larly in the absence of obstructive coronary artery disease. CMD is prevalent in both ANOCA (Angina with Non-Obstructive Coronary Arteries) and HFpEF (Heart Failure with preserved Ejection Fraction), and is associated with poor clinical outcomes, including hospitalization and mortality. However, CMD remains frequently underdiagnosed due to the lack of simple, non-invasive diagnostic tools and the complexity of invasive assessment techniques such as the Index of Microcirculatory Resistance (IMR) and corrected Fractional Flow Reserve (cFR).
Cardiopulmonary exercise testing (CPET) and echocardiography are widely accessible and routinely used modalities that may reflect hemodynamic consequences of CMD. CPET pro-vides a comprehensive assessment of cardiopulmonary performance and exercise tolerance, while echocardiography allows for non-invasive evaluation of diastolic function, left atrial pressure, and right heart-pulmonary interactions. Nevertheless, the extent to which these measures correlate with invasive CMD parameters has not been systematically studied.
Heart and Diabetes Center North-Rhine Westfalia is the lead sponsor of 35 studies on the registry; 7 are open to participants now.
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Exclusion Criteria:
Significant structural heart disease (e.g., severe valvular disease)
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
COPD
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Patients with angina and/or exertional dyspnea without obstructive coronary artery disease (ANOCA or HFpEF phenotype).
Diagnostic Test: All participants will undergo cardiopulmonary exercise testing (CPET), transthoracic echocardiography, and invasive coronary angiography with functional microvascular assessment (IMR, cFR, RFR). No in
Control individuals without evidence of coronary or myocardial disease, microvascular dysfunction or heart failure with preserved ejection fraction
Diagnostic Test: All participants will undergo cardiopulmonary exercise testing (CPET), transthoracic echocardiography, and invasive coronary angiography with functional microvascular assessment (IMR, cFR, RFR). No in
This is a prospective, observational, controlled cohort study including patients with suspected coronary microvascular dysfunction (CMD) presenting as ANOCA or HFpEF and asymptomatic control individuals without evidence of coronary or myocardial disease, microvascular dysfunction or heart failure with preserved ejection fraction. All participants will undergo cardiopulmonary exercise testing (CPET), transthoracic echocardiography, and invasive coronary angiography with functional microvascular assessment (IMR, cFR, RFR). No interventions outside of standard clinical care will be performed. Comparative analyses will focus on correlations between CPET parameters, echocardiographic markers, and invasive microvascular indices, as well as differences between symptomatic patients and controls. The study will include: * Patients with angina and/or exertional dyspnea without obstructive coronary artery disease (ANOCA or HFpEF phenotype). * Control individuals without evidence of coronary or my
Correlation Between Peak Oxygen Uptake (VO₂peak) and Index of Microcirculatory Resistance (IMR)
Correlation between peak oxygen uptake (VO₂peak), measured by cardiopulmonary exercise testing (CPET), and the index of microcirculatory resistance (IMR), measured during invasive coronary angiography. The association will be quantified using Pearson's or Spearman's correlation coefficient, as appropriate. The correlation coefficient is dimensionless.
Time frame: Baseline (during the initial diagnostic assessment)
Correlation Between Peak Oxygen Uptake (VO₂peak) and CFR
Correlation between peak oxygen uptake (VO₂peak), measured by cardiopulmonary exercise testing (CPET), and CFR, assessed during invasive coronary angiography. The association will be quantified using Pearson's or Spearman's correlation coefficient, as appropriate. The correlation coefficient is dimensionless.
Time frame: Baseline (during the initial diagnostic assessment)
Correlation Between Peak Oxygen Uptake (VO₂peak) and Resting Full-Cycle Ratio (RFR)
Correlation between peak oxygen uptake (VO₂peak), measured by cardiopulmonary exercise testing (CPET), and resting full-cycle ratio (RFR), assessed during invasive coronary angiography. The association will be quantified using Pearson's or Spearman's correlation coefficient, as appropriate. The correlation coefficient is dimensionless.
Time frame: Baseline (during the initial diagnostic assessment)
Correlation Between VE/VCO₂ Slope and Index of Microcirculatory Resistance (IMR)
Correlation between the ventilatory efficiency parameter VE/VCO₂ slope, measured by cardiopulmonary exercise testing (CPET), and the index of microcirculatory resistance (IMR), assessed during invasive coronary angiography. The association will be quantified using Pearson's or Spearman's correlation coefficient, as appropriate. The correlation coefficient is dimensionless.
Time frame: Baseline (during the initial diagnostic assessment)
Correlation Between VE/VCO₂ Slope and CFR
Correlation between the ventilatory efficiency parameter VE/VCO₂ slope, measured by cardiopulmonary exercise testing (CPET), and CFR, assessed during invasive coronary angiography. The association will be quantified using Pearson's or Spearman's correlation coefficient, as appropriate. The correlation coefficient is dimensionless.
Time frame: Baseline (during the initial diagnostic assessment)
Correlation Between VE/VCO₂ Slope and Resting Full-Cycle Ratio (RFR)
Correlation between the ventilatory efficiency parameter VE/VCO₂ slope, measured by cardiopulmonary exercise testing (CPET), and resting full-cycle ratio (RFR), assessed during invasive coronary angiography. The association will be quantified using Pearson's or Spearman's correlation coefficient, as appropriate. The correlation coefficient is dimensionless.
Time frame: Baseline (during the initial diagnostic assessment)
Correlation Between Oxygen Pulse and Index of Microcirculatory Resistance (IMR)
Correlation between oxygen pulse (O₂ pulse), measured by cardiopulmonary exercise testing (CPET), and the index of microcirculatory resistance (IMR), assessed during invasive coronary angiography. The association will be quantified using Pearson's or Spearman's correlation coefficient, as appropriate. The correlation coefficient is dimensionless.
Time frame: Baseline (during the initial diagnostic assessment)
Correlation Between Oxygen Pulse and CFR
Correlation between oxygen pulse (O₂ pulse), measured by cardiopulmonary exercise testing (CPET), and cFR, assessed during invasive coronary angiography. The association will be quantified using Pearson's or Spearman's correlation coefficient, as appropriate. The correlation coefficient is dimensionless.
Time frame: Baseline (during the initial diagnostic assessment)
Correlation Between Oxygen Pulse and Resting Full-Cycle Ratio (RFR)
Correlation between oxygen pulse (O₂ pulse), measured by cardiopulmonary exercise testing (CPET), and resting full-cycle ratio (RFR), assessed during invasive coronary angiography. The association will be quantified using Pearson's or Spearman's correlation coefficient, as appropriate. The correlation coefficient is dimensionless.
Time frame: Baseline (during the initial diagnostic assessment)
Correlation Between E/e' Ratio and Index of Microcirculatory Resistance (IMR)
Correlation between the echocardiographically assessed E/e' ratio, a marker of left ventricular filling pressure, and the index of microcirculatory resistance (IMR), measured during invasive coronary angiography. The association will be quantified using Pearson's or Spearman's correlation coefficient, as appropriate. The correlation coefficient is dimensionless.
Time frame: Baseline (during the initial diagnostic assessment)
Correlation Between E/e' Ratio and cFR
Correlation between the echocardiographically assessed E/e' ratio and cFR, measured during invasive coronary angiography. The association will be quantified using Pearson's or Spearman's correlation coefficient, as appropriate. The correlation coefficient is dimensionless.
Time frame: Baseline (during the initial diagnostic assessment)
Correlation Between E/e' Ratio and Resting Full-Cycle Ratio (RFR)
Correlation between the echocardiographically assessed E/e' ratio and resting full-cycle ratio (RFR), measured during invasive coronary angiography. The association will be quantified using Pearson's or Spearman's correlation coefficient, as appropriate. The correlation coefficient is dimensionless.
Time frame: Baseline (during the initial diagnostic assessment)
Correlation Between Left Atrial Volume Index (LAVI) and Index of Microcirculatory Resistance (IMR)
Correlation between left atrial volume index (LAVI), assessed by transthoracic echocardiography and expressed in mL/m², and the index of microcirculatory resistance (IMR), measured during invasive coronary angiography. The association will be quantified using Pearson's or Spearman's correlation coefficient, as appropriate. The correlation coefficient is dimensionless.
Time frame: Baseline (during the initial diagnostic assessment)
Correlation Between Left Atrial Volume Index (LAVI) and cFR
Correlation between left atrial volume index (LAVI), assessed by transthoracic echocardiography and expressed in mL/m², and cFR, measured during invasive coronary angiography. The association will be quantified using Pearson's or Spearman's correlation coefficient, as appropriate. The correlation coefficient is dimensionless.
Time frame: Baseline (during the initial diagnostic assessment)
Correlation Between Left Atrial Volume Index (LAVI) and Resting Full-Cycle Ratio (RFR)
Correlation between left atrial volume index (LAVI), assessed by transthoracic echocardiography and expressed in mL/m², and resting full-cycle ratio (RFR), measured during invasive coronary angiography. The association will be quantified using Pearson's or Spearman's correlation coefficient, as appropriate. The correlation coefficient is dimensionless.
Time frame: Baseline (during the initial diagnostic assessment)
Correlation Between TAPSE/PASP Ratio and Index of Microcirculatory Resistance (IMR)
Correlation between the ratio of tricuspid annular plane systolic excursion to pulmonary artery systolic pressure (TAPSE/PASP), assessed by transthoracic echocardiography as an index of right ventricular-pulmonary arterial coupling, and the index of microcirculatory resistance (IMR), measured during invasive coronary angiography. The association will be quantified using Pearson's or Spearman's correlation coefficient, as appropriate. The correlation coefficient is dimensionless.
Time frame: Baseline (during the initial diagnostic assessment)
Correlation Between TAPSE/PASP Ratio and cFR
Correlation between the echocardiographically assessed TAPSE/PASP ratio, an index of right ventricular-pulmonary arterial coupling, and cFR, measured during invasive coronary angiography. The association will be quantified using Pearson's or Spearman's correlation coefficient, as appropriate. The correlation coefficient is dimensionless.
Time frame: Baseline (during the initial diagnostic assessment)
Correlation Between TAPSE/PASP Ratio and Resting Full-Cycle Ratio (RFR)
Correlation between the echocardiographically assessed TAPSE/PASP ratio, an index of right ventricular-pulmonary arterial coupling, and resting full-cycle ratio (RFR), measured during invasive coronary angiography. The association will be quantified using Pearson's or Spearman's correlation coefficient, as appropriate. The correlation coefficient is dimensionless.
Time frame: Baseline (during the initial diagnostic assessment)
Number of Distinct Coronary Microvascular Dysfunction Phenotypes Identified by Cluster Analysis
Number of distinct phenotypic clusters identified among symptomatic patients with ANOCA or HFpEF using unsupervised cluster analysis of baseline cardiopulmonary exercise testing parameters, echocardiographic markers, and invasive coronary physiological indices.
Time frame: Baseline (during the initial diagnostic assessment)
Plan to share: No
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Started Aug 2025 (actual). Primary completion is estimated for Jun 2029, 45 months after the start.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Heart and Diabetes Center North-Rhine Westfalia