Coronary microvascular dysfunction is associated with cardiac time intervals in women with angina and no obstructive coronary artery disease: An iPOWER substudy

Assessment and Treatment for Coronary Microvascular Dysfunction by Contrast Enhanced Ultrasound

With growing evidence in clinical practice, the understanding of coronary syndromes has gradually evolved out of focusing on the well-established link between stenosis of epicardial coronary artery and myocardial ischemia to the structural and functional abnormalities at the level of coronary microcirculation, known as coronary microvascular dysfunction (CMD). CMD encompasses several pathophysiological mechanisms of coronary microcirculation and is considered as an important cause of myocardial ischemia in patients with angina symptoms without obstructive coronary artery disease (CAD). As a result of growing knowledge of the understanding of CMD assessed by multiple non-invasive modalities, CMD has also been found to be involved in other cardiovascular diseases, including primary cardiomyopathies as well as heart failure with preserved ejection fraction (HFpEF). In the past 2 decades, almost all the imaging modalities have been used to non-invasively quantify myocardial blood flow (MBF) and promote a better understanding of CMD. Myocardial contrast echocardiography (MCE) is a breakthrough as a non-invasive technique, which enables assessment of myocardial perfusion and quantification of MBF, exhibiting promising diagnostic performances that were comparable to other non-invasive techniques. With unique advantages over other non-invasive techniques, MCE has gradually developed into a novel modality for assessment of the coronary microvasculature, which may provide novel insights into the pathophysiological role of CMD in different clinical conditions. Moreover, the sonothrombolysis and the application of artificial intelligence (AI) will offer the opportunity to extend the use of contrast ultrasound theragnostics.

PathoClock and PhysioClock in mice recapitulate human multimorbidity and heterogeneous aging

BACKGROUND

Multimorbidity is a public health concern and an essential component of aging and healthspan but understudied because investigative tools are lacking that can be translatable to capture similarities and differences of the aging process across species and variability between individuals and individual organs.

METHODS

To help address this need, body organ disease number (BODN) borrowed from human studies was applied to C57BL/6 (B6) and CB6F1 mouse strains at 8, 16, 24, and 32 months of age, as a measure of systems morbidity based on pathology lesions to develop a mouse PathoClock resembling clinically-based Body Clock in humans, using Bayesian inference. A mouse PhysioClock was also developed based on measures of physiological domains including cardiovascular, neuromuscular, and cognitive function in the same two mouse strains so that alignment with BODN was predictable.

RESULTS

Between- and within-age variabilities in PathoClock and PhysioClock, as well as between-strain variabilities. Both PathoClock and PhysioClock correlated with chronological age more strongly in CB6F1 than C57BL/6. Prediction models were then developed, designated as PathoAge and PhysioAge, using regression models of pathology and physiology measures on chronological age. PathoAge better predicted chronological age than PhysioAge as the predicted chronological and observed chronological age for PhysioAge were complex rather than linear.

CONCLUSION

PathoClock and PhathoAge can be used to capture biological changes that predict BODN, a metric developed in humans, and compare multimorbidity across species. These mouse clocks are potential translational tools that could be used in aging intervention studies.

Vasomotor Dysfunction in Patients with Ischemia and Non-Obstructive Coronary Artery Disease: Current Diagnostic and Therapeutic Strategies

Many patients who present with symptoms or objective evidence of ischemia have no or non-physiologically-significant disease on invasive coronary angiography. The diagnosis of ischemic heart disease is thus often dismissed, and patients receive false reassurance or other diagnoses are pursued. We now know that a significant proportion of these patients have coronary microvascular dysfunction and/or vasospastic disease as the underlying pathophysiology of their clinical presentation. Making the correct diagnosis of such abnormalities is important not only because they impact the quality of life, with recurring symptoms and unnecessary repeated testing, but also because they increase the risk for adverse cardiovascular events. The mainstay of diagnosis remains an invasive comprehensive physiologic assessment, which further allows stratifying these patients into appropriate “endotypes”. It has been shown that tailoring treatment to the patient’s assigned endotype improves symptoms and quality of life. In addition to the conventional drugs used in chronic stable angina, multiple newer agents are being investigated. Moreover, innovative non-pharmacologic and interventional therapies are emerging to provide a bail-out in refractory cases. Many of these novel therapies fail to show consistent benefits, but others show quite promising results.

Myocardial performance index is associated with cardiac computed tomography findings in patients with suspected coronary artery disease

BACKGROUND

Studies suggest cardiac time intervals to be associated with cardiac ischemia. A novel method to assess cardiac time intervals by tissue Doppler echocardiography has been proposed. Cardiac time intervals can assess the myocardial performance index (MPI), which quantifies the proportion of time spent contributing effective myocardial work. We hypothesized that MPI associates with coronary artery lesions detected by cardiac computed tomography (CT) in patients suspected of coronary artery disease (CAD).

METHODS

We investigated patients referred for cardiac CT under suspicion of CAD who had an echocardiogram performed. Curved m-mode tissue Doppler imaging was used to measure cardiac time intervals and MPI. The outcome was coronary artery lesions, defined as a calcium score > 400 and/or coronary artery stenosis (>70% luminal narrowing). Logistic regression was applied with multivariable models including: (a) SCORE chart risk factors and (b) SCORE chart risk factors, body mass index, dyslipidemia, familial history of CAD, diabetes mellitus, LVEF, and left ventricular mass index.

RESULTS

Of 404 patients, 41 (10%) had a coronary artery lesion. Overall, 42% were male, mean age was 58 years, and LVEF was 58%. Patients with coronary artery lesions exhibited higher MPI than those without (0.52 vs. 0.44, P < .001). MPI associated with coronary artery lesions in unadjusted analyses (OR = 1.69 [1.30-2.19], per 0.1 increase), and this association persisted when adjusted for SCORE chart risk factors (OR = 1.55 [1.16-2.07], P = .003, per 0.1 increase), and additional risk factors (OR = 1.64 [1.11-2.41], P = .013, per 0.1 increase).

CONCLUSION

Curved m-mode-derived MPI is associated with coronary artery lesions detected by cardiac CT in suspected CAD patients.