What is the clinical evidence from this study?

Study design: Cross-Sectional. Population: Angina with non-obstructive coronary artery disease (n=85). Intervention: Coronary microvascular dysfunction (CFR < 2.5) vs. Normal coronary flow reserve (CFR ≥ 2.5). Primary outcome: Inducible ischemia (hyperemic endo/epi < 1.0) (p=<0.001).

What question did this study set out to answer?

This research investigates the relationship between coronary microvascular dysfunction and exercise-induced myocardial ischemia in patients with nonobstructive coronary artery disease.

November 11, 2019CirculationOpen Access

Coronary Microvascular Dysfunction Is Associated With Myocardial Ischemia and Abnormal Coronary Perfusion During Exercise

Q: What are the key findings of this study?

In patients with angina and non-obstructive coronary artery disease, coronary microvascular dysfunction was associated with a higher rate of inducible ischemia (82% vs 22%) compared to controls.

Q: What question did this study set out to answer?

This research investigates the relationship between coronary microvascular dysfunction and exercise-induced myocardial ischemia in patients with nonobstructive coronary artery disease.

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Key result

Coronary microvascular dysfunction links to an 82% rate of inducible ischemia in non-obstructive CAD.

P<0.001
n=85

Why the study?

It was unknown whether diminished coronary vasodilator response correlates with abnormal exercise physiology or inducible myocardial ischemia in patients with nonobstructive coronary artery disease.

Does coronary microvascular dysfunction (CFR < 2.5) correlate with abnormal exercise perfusion efficiency and inducible myocardial ischemia in patients with angina and non-obstructive coronary artery disease?

Population

Patients with angina and nonobstructive coronary artery disease

Comparison

MVD (coronary flow reserve <2.5) vs controls (coronary flow reserve ≥2.5)

Design

Blinded physiological cohort study

Authors

HRHaseeb RahmanGuy's and St Thomas' NHS Foundation Trust MRM. J. RyanInterventional Cardiology MLMatthew LumleyCardiac Imaging

Discussion

Member takes

Implication

CMD marks higher inducible ischemia risk in angina with nonobstructive CAD; leaves open whether targeting MVD improves outcomes.

Key Points

This research investigates the relationship between coronary microvascular dysfunction and exercise-induced myocardial ischemia in patients with nonobstructive coronary artery disease.
Patients with angina and nonobstructive coronary artery disease underwent dual sensor-tipped guidewire measurements of coronary pressure and flow velocity during various conditions.
Microvascular resistance was calculated using coronary pressure and flow velocity data.
Cardiac magnetic resonance imaging assessed myocardial blood flow and perfusion ratios during rest and hyperemia.
Patients with coronary flow reserve <2.5 showed evidence of inducible ischemia as defined by a hyperemic subendocardial:subepicardial perfusion ratio <1.0.
Functional and structural microvascular dysfunction exhibited similar exercise perfusion efficiency values.
Two distinct endotypes of microvascular dysfunction were identified with different systemic responses to exercise.

Study Design

Type

Cross-Sectional (n=85)

Blinding

Single-blind

Multicenter

Structured PICO

Population

85 patients with angina and non-obstructive coronary artery disease (LVEF >50%, <30% diameter stenosis and/or FFR >0.80), mean age 57±10 years, 78% female, UK-based. Excluded: intolerance to adenosine, eGFR <30 mL/min/m2, concomitant valve disease, recent acute coronary syndrome, cardiomyopathy, or neuromuscular comorbidity.

Intervention

Coronary microvascular dysfunction (MVD), defined as coronary flow reserve (CFR) < 2.5 measured via dual sensor-tipped guidewire during adenosine-mediated hyperemia (140mcg/kg/min).

Comparator

Controls with normal coronary flow reserve (CFR ≥ 2.5).

Outcome

Co-primary endpoints: exercise perfusion efficiency (percentage of accelerating wave intensity) and frequency of inducible ischemia (defined as hyperemic subendocardial:subepicardial perfusion ratio < 1.0 on 3-Tesla perfusion CMR).surrogate

Main Result

Absolute Event Rate: 82% vs 22%

p-value: p=<0.001

In patients with angina and non-obstructive coronary artery disease, diminished coronary flow reserve identifies a phenotype with inducible ischemia and maladaptive physiological responses to exercise, comprising both functional and structural endotypes.

Cite This Study

Rahman et al. (2019) conducted a cross-sectional in Angina with non-obstructive coronary artery disease (n=85). Coronary microvascular dysfunction (CFR < 2.5) vs. Normal coronary flow reserve (CFR ≥ 2.5) was evaluated on Inducible ischemia (hyperemic endo/epi < 1.0) (p=<0.001). In patients with angina and non-obstructive coronary artery disease, coronary microvascular dysfunction was associated with a higher rate of inducible ischemia (82% vs 22%) compared to controls.

synapsesocial.com/papers/6a0662f93f8bf83a443dd9bb https://doi.org/10.1161/circulationaha.119.041595

Topics

Coronary artery disease Coronary CT angiography

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Coronary Microvascular Dysfunction Is Associated With Myocardial Ischemia and Abnormal Coronary Perfusion During Exercise

Discussion

Member takes

Implication

Key Points

Study Design

Structured PICO

Main Result

Cite This Study

Topics

Coronary Microvascular Dysfunction Is Associated With Myocardial Ischemia and Abnormal Coronary Perfusion During Exercise

Discussion

Member takes

Implication

Key Points

Study Design

Structured PICO

Main Result

Cite This Study

Also Consider

Topics

Also Consider