Coronary Physiology in the Cardiac Catheterization Laboratory

Coronary microvascular dysfunction

Coronary microvascular dysfunction (CMD) is a key mechanism underlying ischemic heart disease (IHD), yet its diagnosis and treatment remain challenging. This article presents a comprehensive overview of CMD research, covering its pathogenesis, diagnostic criteria, assessment techniques, risk factors, and therapeutic strategies. Additionally, it highlights the prospects for future CMD research. The article aims at advocating early and effective intervention for CMD and improving the prognosis of IHD.

Illness Perception and the Impact of a Definitive Diagnosis on Women With Ischemia and No Obstructive Coronary Artery Disease: A Qualitative Study

BACKGROUND

Ischemia and no obstructive coronary artery disease (INOCA) disproportionately impacts women, yet the underlying pathologies are often not distinguished, contributing to adverse health care experiences and poor quality of life. Coronary function testing at the time of invasive coronary angiography allows for improved diagnostic accuracy. Despite increased recognition of INOCA and expanding access to testing, data lack on first-person perspectives and the impact of receiving a diagnosis in women with INOCA.

METHODS

From 2020 to 2021, we conducted structured telephone interviews with 2 groups of women with INOCA who underwent invasive coronary angiography (n=29) at Yale New Haven Hospital, New Haven, CT: 1 group underwent coronary function testing (n=20, of whom 18 received a mechanism-based diagnosis) and the other group who did not undergo coronary function testing (n=9). The interviews were analyzed using the constant comparison method by a multidisciplinary team.

RESULTS

The mean age was 59.7 years, and 79% and 3% were non-Hispanic White and non-Hispanic Black, respectively. Through iterative coding, 4 themes emerged and were further separated into subthemes that highlight disease experience aspects to be addressed in patient care: (1) distress from symptoms of uncertain cause: symptom constellation, struggle for sensemaking, emotional toll, threat to personal and professional identity; (2) a long journey to reach a definitive diagnosis: self-advocacy and fortitude, healthcare interactions brought about further uncertainty and trauma, therapeutic alliance, sources of information; (3) establishing a diagnosis enabled a path forward: relief and validation, empowerment; and (4) commitment to promoting awareness and supporting other women: recognition of sex and racial/ethnic disparities, support for other women.

CONCLUSIONS

Insights about how women experience the symptoms of INOCA and their interactions with clinicians and the healthcare system hold powerful lessons for more patient-centered care. A coronary function testing-informed diagnosis greatly influences the healthcare experiences, quality of life, and emotional states of women with INOCA.

Computing intracoronary blood flow rate under incomplete boundary conditions: Combing coronary anatomy and fractional flow reserve

BACKGROUND

Accurate measurement of intracoronary blood flow rate is of great significance for the diagnosis of ischemic heart disease (IHD). Computational fluid dynamic (CFD) method, combining coronary angiography images and fractional flow reserve (FFR), provides a new way to calculate the mean flow rate. However, due to the incomplete boundary conditions obtained by FFR, side branches were ignored which was likely to have a significant impact on the accuracy. In this paper, a novel CFD based method for calculating the mean intracoronary flow rate under incomplete pressure boundary conditions was proposed, in order to improve the accuracy by including the side branches.

METHODS

A pressure-flow curve based flow resistance model was employed to model resistance of the epicardial arteries. A series of steady flow simulations were performed to extract the parameters of the flow resistance model, which implicitly specified constraints for splitting flow between branches and thus enabled the mean intracoronary blood flow rate to be calculated in two or more branches under incomplete pressure boundary conditions. Simulation experiments were designed to validate the proposed method in both idealized and reconstructed 3D models of coronary branches, and the impact of the assumed coefficient of the Murray's Law for splitting flow between branches was also investigated.

RESULTS

The mean percentage error of the proposed method was +2.05%±0.04% for idealized models and +2.24%±0.01% for reconstructed models, and it was much lower than that of the method ignoring side branches (+38.48%±10.45% for idealized models and +30.54%±6.12% for reconstructed models). When the assumed coefficient of the Murray's Law was inconsistent with the real blood flow condition, the percentage errors still maintained less than about 3.00%.

CONCLUSIONS

The proposed method provided an easy and accurate way to measure the mean intracoronary flow rate and would facilitate the accurate diagnosis of IHD.

New horizons in Type 2 myocardial infarction: pathogenesis, assessment and management of an emerging geriatric disease

Type 2 myocardial infarction (MI) is characterised by a functional imbalance between myocardial oxygen supply and demand in the absence of a thrombotic process, leading to myocardial necrosis. This type of MI was relatively unknown among clinicians until the third universal definition of MI was published in 2017, differentiating Type 2 from Type 1 MI, which follows an acute atherothrombotic event. The pathogenesis, diagnostic and therapeutic aspects of Type 2 MI are described in the present review. Type 2 MI is a condition that is strongly linked to age because of vascular ageing concerning both epicardic vessels and microcirculation, age-related atherosclerosis and stress maladaptation. This condition predominantly affects multimorbid individuals with a history of cardiovascular disease. However, the conditions that lead to the functional imbalance between oxygen supply and demand are frequently extra-cardiac (e.g. pneumonia or anaemia). The great heterogeneity of the underlying etiological factors requires a comprehensive approach that is tailored to each case. In the absence of evidence for the benefit of invasive reperfusion strategies, the treatment of Type 2 MI remains to date essentially based on the restoration of the balance between oxygen supply and demand. For older co-morbid patients with Type 2 MI, geriatricians and cardiologists need to work together to optimise etiological investigations, treatment and prevention of predisposing conditions and precipitating factors.

The Foundational Role of Cardiovascular Imaging in the Characterization of Mental Stress-Induced Myocardial Ischemia in Patients with Coronary Artery Disease

PURPOSE OF REVIEW

Mental stress-provoked myocardial ischemia (MSIMI) is an ischemic phenomenon provoked by the experience of psychologically stressful circumstances. While MSIMI was initially identified 50 years ago during activities of daily living through the use of wearable Holter monitor, subsequent research utilized the technologies of cardiac imaging-ventriculography and myocardial perfusion-under controlled conditions to pursue an understanding of pathophysiology and prognosis. This work revealed that MSIMI occurs in almost half of patients with stable coronary artery disease (CAD) and is associated with cardiac events and early mortality. We provide a focused review of the instrumental role that cardiac imaging has played in elucidating how stress affects cardiac physiology and how emerging diagnostic techniques will allow for further research on stress-mediated changes in the coronary macro- and microvasculature.

RECENT FINDINGS

Observations about the cardiac response to mental stress diverge from underlying cornerstones of the traditional CAD paradigm which is based upon myocardial oxygen demand and the degree of epicardial coronary stenosis. Evidence from studies utilizing non-invasive and invasive studies of coronary perfusion indicates perturbations in the microvascular compartment in response to mental stress. Cardiovascular imaging enjoined with mental stress provocation may be a commanding tool to advance our understanding of non-obstructive CAD and the coronary microvasculature. This further understanding will facilitate incorporation of mental stress testing in the clinical care of patients with discrepant diagnostic work-up of CAD and in patients who experience anginal symptoms due to non-exertional and/or emotional triggers. Such algorithms will be crucial to identify treatment targets to modify the risk associated with mental stress-associated ischemia and adverse prognosis.

Pathobiology of cardiovascular diseases: an update

This article introduces the Second Special Issue of Cardiovascular Pathology (CVP), the official journal of the Society for Cardiovascular Pathology (SCVP). This CVP Special Issue showcases a series of commemorative review articles in celebration of the 25th anniversary of CVP originally published in 2016 and now compiled into a virtual collection with online access for the cardiovascular pathology community. This overview also provides updates on the major categories of cardiovascular diseases from the perspective of cardiovascular pathologists, highlighting publications from CVP, as well as additional important review articles and clinicopathologic references.