Epicardial and microvascular coronary vasomotor dysfunction and its relation to myocardial ischemic burden in patients with non-obstructive coronary artery disease

The relationship between workload and exercise-induced cardiac troponin elevations is influenced by non-obstructive coronary atherosclerosis

The relationship between exercise-induced troponin elevation and non-obstructive coronary artery disease (CAD) is unclear. This observational study assessed non-obstructive CAD's impact on exercise-induced cardiac Troponin I (cTnI) elevation in middle-aged recreational athletes. cTnI levels of 40 well-trained recreational athletes (73% males, 50 ± 9 years old) were assessed by a high-sensitive cTnI assay 24 h before, and at 3 and 24 h following two high-intensity exercises of different durations; a cardiopulmonary exercise test (CPET), and a 91-km mountain bike race. Workload was measured with power meters. Coronary computed tomography angiography was used to determine the presence or absence of non-obstructive (<50% obstruction) CAD. A total of 15 individuals had non-obstructive CAD (Atherosclerotic group), whereas 25 had no atherosclerosis (normal). There were higher post-exercise cTnI levels following the race compared with CPET, both at 3 h (77.0 (35.3-112.4) ng/L vs. 11.6 (6.4-22.5) ng/L, p < 0.001) and at 24 h (14.7 (6.7-16.3) vs. 5.0 (2.6-8.9) ng/L, p < 0.001). Absolute cTnI values did not differ among groups. Still, the association of cTnI response to power output was significantly stronger in the CAD versus Normal group both at 3 h post-exercise (Rho = 0.80, p < 0.001 vs. Rho = -0.20, p = 0.33) and 24-h post-exercise (Rho = 0.87, p < 0.001 vs. Rho = -0.13, p = 0.55). Exercise-induced cTnI elevation was strongly correlated with exercise workload in middle-aged athletes with non-obstructive CAD but not in individuals without CAD. This finding suggests that CAD influences the relationship between exercise workload and the cTnI response even without coronary artery obstruction.

A Comparison of Dynamic SPECT Coronary Flow Reserve with TIMI Frame Count in the Treatment of Non-Obstructive Epicardial Coronary Patients

Background

Microvascular dysfunction in patients with non-obstructive epicardial coronary may aggravate patient's symptoms or lead to various clinical events.

Objective

To investigate the correlation between dynamic single photon emission computed tomography (D-SPECT) derived coronary flow reserve (CFR) and TIMI frame count (TFC) in patients with non-obstructive epicardial coronary patients.

Methods

Patients with suspected or known stable CAD who were recommended to undergo invasive coronary angiography were prospectively enrolled in this study. Those who had non-obstructive coronary received TIMI frame count (TFC) and D-SPECT. A cut-off value of >40 was defined as slow flow referred to TFC.

Results

A total of 47 patients diagnosed with non-obstructive coronary were enrolled. The mean age of patients was 66.09 ± 8.36 years, and 46.8% were male. Dynamic SPECT derived coronary flow reserve (CFR) was significantly correlated with TIMI frame count in 3 epicardial coronary (LAD: r=-0.506, P = 0.0003; LCX: r= -0.532, P = 0.0001; RCA: r= -0.657, P < 0.0001). The sensitivity and specificity of CFR in identifying abnormal TIMI frame count < 40 was 100.0% and 57.6% in LAD, 62.5% and 87.0% in LCX, 83.9% and 75.0% in RCA, respectively. The optimal CFR cut-off values were 2.02, 2.47, and 1.96 among the three vessels.

Conclusion

In patients with non-obstructive coronary, CFR derived from D-SPECT was strongly correlated with TFC. This study demonstrates that that CFR may be an alternative non-invasive method for identifying slow flow in non-obstructive coronary.

Association of vascular endothelial function and quality of life in patients with ischemia and non-obstructive coronary artery disease

Improvements are required in the quality of life (QoL) of patients with ischemia and non-obstructive coronary artery disease (INOCA). Several patients with INOCA experience vascular endothelial dysfunction. However, the relationship between endothelial function and QoL remains unelucidated. This study aimed to initially investigate the relationship between endothelial function and QoL in patients with INOCA. This prospective observational study included 121 patients with INOCA (aged 31-85 years). Vascular endothelial function was assessed by flow-mediated dilatation (FMD) of the peripheral brachial artery. QoL was evaluated using the 36-Item Short-Form Health Survey (SF-36). Patients with INOCA were divided into two groups according to the median FMD change during the 1-year follow-up (group A, ≥ median FMD change cut-off; group B, < median FMD change cut-off). The median change in FMD was 0.92%. The mean baseline SF-36 scores were comparable between the two groups (53.95 ± 6.46 vs. 53.92 ± 4.29, p = 0.98). The QoL at follow-up was better in group A than in group B (56.61 ± 5.50 vs. 53.32 ± 5.58, p = 0.002). The change in FMD (r = 0.34, p < 0.01), rather than FMD at baseline (r = - 0.01, p = 0.89) or follow-up (r = 0.13, p = 0.15), was related to the follow-up SF-36 scores. FMD improvement was an independent predictor of increased QoL (odds ratio, 3.90; 95% confidence interval: 1.59-9.53, p = 0.003). Endothelial function change is associated with QoL, and patients with improved endothelial function have a better QoL than those without.

Prevalence of Coronary Microvascular Disease and Coronary Vasospasm in Patients With Nonobstructive Coronary Artery Disease: Systematic Review and Meta-Analysis

Background

A relevant proportion of patients with suspected coronary artery disease undergo invasive coronary angiography showing normal or nonobstructive coronary arteries. However, the prevalence of coronary microvascular disease (CMD) and coronary spasm in patients with nonobstructive coronary artery disease remains to be determined. The objective of this study was to determine the prevalence of coronary CMD and coronary vasospastic angina in patients with no obstructive coronary artery disease.

Methods and Results

A systematic review and meta‐analysis of studies assessing the prevalence of CMD and vasospastic angina in patients with no obstructive coronary artery disease was performed. Random‐effects models were used to determine the prevalence of these 2 disease entities. Fifty‐six studies comprising 14 427 patients were included. The pooled prevalence of CMD was 0.41 (95% CI, 0.36–0.47), epicardial vasospasm 0.40 (95% CI, 0.34–0.46) and microvascular spasm 24% (95% CI, 0.21–0.28). The prevalence of combined CMD and vasospastic angina was 0.23 (95% CI, 0.17–0.31). Female patients had a higher risk of presenting with CMD compared with male patients (risk ratio, 1.45 [95% CI, 1.11–1.90]). CMD prevalence was similar when assessed using noninvasive or invasive diagnostic methods.

Conclusions

In patients with no obstructive coronary artery disease, approximately half of the cases were reported to have CMD and/or coronary spasm. CMD was more prevalent among female patients. Greater awareness among physicians of ischemia with no obstructive coronary arteries is urgently needed for accurate diagnosis and patient‐tailored management.

Total coronary atherosclerotic plaque burden is associated with myocardial ischemia in non-obstructive coronary artery disease

AIM

Whether the total coronary atherosclerotic plaque burden is independently associated with myocardial ischemia in non-obstructive coronary artery disease (CAD) is not well established. We aimed to test the association of total plaque burden quantified by coronary computed tomography angiography (CCTA) with myocardial ischemia in patients with chronic coronary syndrome and non-obstructive CAD.

METHODS

We included 125 patients (age 62 ± 9 years, 58% women) with chronic coronary syndrome and non-obstructive CAD (stenosis < 50%) by CCTA, who were grouped according to presence or absence of myocardial ischemia by myocardial contrast stress echocardiography. Total plaque burden was quantified by CCTA as the total plaque volume in the main coronary arteries, and positive remodelling was defined as remodelling index > 1.10.

RESULTS

Patients with myocardial ischemia (n = 66) had higher total plaque burden (847 ± 245 mm3 vs. 758 ± 251 mm3, p = 0.049) and higher left ventricular (LV) mass index (42.1 ± 9.9 g/m2.7 vs. 37.3 ± 8.0 g/m2.7, p = 0.004), while age, sex, prevalence of hypertension, diabetes, calcium score and positive remodelling did not differ between the groups (all p > 0.05). In multivariable regression analysis, total plaque burden remained associated with presence of myocardial ischemia (OR 1.02, 95% CI 1.00-1.04, p = 0.045) independent of age, sex, hypertension, diabetes, LV mass index, coronary calcium score and positive remodelling.

CONCLUSION

Total coronary artery plaque burden by CCTA was independently associated with myocardial ischemia in patients with non-obstructive CAD. Whether plaque quantification is useful for clinical management of patients with non-obstructive CAD should be tested in prospective studies.ClinicalTrials.gov: Identifier NCT01853527.

Ischaemia with no obstructive coronary arteries

Ischaemia with no obstructive coronary arteries (INOCA) is a common ischaemic heart disease with a female preponderance, mostly due to underlying coronary vascular dysfunction comprising coronary microvascular dysfunction and/or epicardial coronary vasospasm. Since standard ischaemia detection tests and coronary angiograms are not suitable to diagnose coronary vascular dysfunction, INOCA is often overlooked in current cardiology practice. Future research, including large outcome trials, is much awaited. Yet, adequate diagnosis is possible and treatment options are available and vital to reduce symptoms and most probably improve cardiovascular prognosis. This review intends to give a brief overview of the clinical presentation, underlying pathophysiology, and the diagnostic and treatment options in patients with suspected INOCA.