Pharmacologic Treatment of Patients With Myocardial Ischemia With No Obstructive Coronary Artery Disease

Ischemia but no obstructive coronary artery disease: more than meets the eye

Symptomatic women with angina are more likely to have ischemia with no obstructive coronary arteries (INOCA) compared to men. In both men and women, the finding of INOCA is not benign and is associated with adverse cardiovascular events, including myocardial infarction, heart failure and angina hospitalizations. Women with INOCA have more angina and a lower quality of life compared to men, but they are often falsely reassured because of a lack of obstructive coronary artery disease (CAD) and a perception of low risk. Coronary microvascular dysfunction (CMD) is a key pathophysiologic contributor to INOCA, and non-invasive imaging methods are used to detect impaired microvascular flow. Coronary vasospasm is another mechanism of INOCA, and can co-exist with CMD, but usually requires invasive coronary function testing (CFT) with provocation testing for a definitive diagnosis. In addition to traditional heart disease risk factors, inflammatory, hormonal and psychological risk factors that impact microvascular tone are implicated in INOCA. Treatment of risk factors and use of anti-atherosclerotic and anti-anginal medications offer benefit. Increasing awareness and early referral to specialized centers that focus on INOCA management can improve patient-oriented outcomes. However, large, randomized treatment trials to investigate the impact on major adverse cardiovascular events (MACE) are needed. In this focused review, we discuss the prevalence, pathophysiology, presentation, diagnosis and treatment of INOCA.

Rationale and design of the Women's Ischemia Trial to Reduce Events in Nonobstructive CAD (WARRIOR) trial

BACKGROUND

Approximately half of all women with anginal symptoms and/or signs of ischemia and no obstructive coronary artery disease (INOCA) referred for coronary angiography have elevated risk for major adverse cardiac events (MACE), poor quality of life and resource consumption. Yet, guidelines focus on symptom management while clinical practice typically advocates only reassurance. Pilot studies of INOCA subjects suggest benefit with intensive medical therapy (IMT) that includes high-intensity statins and angiotensin converting enzyme inhibitors (ACE-I) or receptor blockers (ARB) to provide the rationale for a randomized pragmatic trial to limit MACE.

METHODS

The Women's IschemiA TRial to Reduce Events In Non-ObstRuctive CAD is a multicenter, prospective, randomized, blinded outcome evaluation (PROBE design) of a pragmatic strategy of IMT vs usual care (UC) in 4,422 symptomatic women with INOCA (NCT03417388) in approximately 70 United States sites. The hypothesis is that IMT will reduce the primary outcome of first occurrence of MACE by 20% vs. UC at ∼2.5 year followup. Secondary outcomes include quality of life, time to return to "duty"/work, healthcare utilization, angina, cardiovascular death and individual primary outcome components over 3 years follow-up. The study utilizes web-based data capture, e-consents, single IRB and centralized pharmacy distribution of strategy medications directly to patients' homes to reduce site and patient burden. A biorepository will collect blood samples to assess potential mechanisms.

CONCLUSIONS

The results of this trial will provide important data necessary to inform guidelines regarding how best to manage this growing and challenging population of women with INOCA.

Research progress on the molecular mechanism of coronary microvascular endothelial cell dysfunction

Coronary microvascular disease is a high-risk factor for many cardiovascular events. However, due to its high concealment and many etiologies, the current understanding of its pathophysiological mechanism is very limited, which greatly limits its clinical diagnosis and treatment. In the process of the occurrence and development of coronary microvascular disease, the damage of coronary microvascular endothelial cell (CMEC) is the core link. CMEC's stress, metabolism, inflammation and other dysfunctions have a causal relationship with coronary microvascular disease, and are also the main features of coronary microvascular disease in the early stage. This article mainly reviews the molecular mechanisms of CMEC damage.

Use of Preventive Medications in Patients With Nonobstructive Coronary Artery Disease: Analysis of the PROMISE Trial

Background

Nonobstructive coronary artery disease (NOCAD) is commonly found on coronary computed tomography angiography (CCTA) during evaluation for coronary artery disease (CAD). There are no guidelines for the medical management of NOCAD, and practice is variable. We aimed to compare patterns of preventive medication use and continuation after identifying NOCAD vs normal coronaries or obstructive CAD on CCTA.

Methods

We analyzed data from the Prospective Multicenter Imaging Study for Evaluation of Chest Pain (PROMISE) trial dataset, restricted to patients with ≥2 follow-up visits after CCTA. We categorized patients as having either obstructive CAD, NOCAD, or normal coronaries. The primary outcome was the proportion of patients reporting continued use of combination preventive medications, defined as a statin, an antithrombotic, and a renin–angiotensin system blocker throughout follow-up after CCTA. Secondary outcomes included the proportion of visits reporting combination therapy and individual medications.

Results

We included 4388 patients, with a mean follow-up of 2.3 years. Most patients had NOCAD (48.6%), with normal coronaries in 38.9%, and obstructive CAD in 10.1%. Among NOCAD patients, the mean age was 61 years, and 47.2% were women. A total of 9.1% of NOCAD patients continued combination therapy, vs 12.4% with obstructive CAD, and 3.3% with normal coronaries (P < 0.001), primarily due to lower use of statins and antithrombotic agents. Similarly, patients with obstructive CAD, NOCAD, and normal coronaries reported using combination therapy during a mean of 35%, 24%, and 9% of visits, respectively (P < 0.001).

Conclusions

Few patients with NOCAD identified by CCTA used or continued combination preventive cardiovascular medications. Patients with NOCAD represent an at-risk population with potential for optimization of preventive medications.

SIRT1/SIRT3 Modulates Redox Homeostasis during Ischemia/Reperfusion in the Aging Heart

Ischemia/reperfusion (I/R) injury is the central cause of global death in cardiovascular diseases, which is characterized by disorders such as angina, stroke, and peripheral vascular disease, finally causing severe debilitating diseases and death. The increased rates of morbidity and mortality caused by I/R are parallel with aging. Aging-associated cardiac physiological structural and functional deterioration were found to contribute to abnormal reactive oxygen species (ROS) production during I/R stress. Disturbed redox homeostasis could further trigger the related signaling pathways that lead to cardiac irreversible damages with mitochondria dysfunction and cell death. It is notable that sirtuin proteins are impaired in aged hearts and are critical to maintaining redox homeostasis via regulating substrate metabolism and inflammation and thus preserving cardiac function under stress. This review discussed the cellular and functional alterations upon I/R especially in aging hearts. We propose that mitochondria are the primary source of reactive oxygen species (ROS) that contribute to I/R injury in aged hearts. Then, we highlight the cardiomyocyte protection of the age-related proteins Sirtuin1 (SIRT1) and Sirtuin1 (SIRT3) in response to I/R injury, and we discuss their modulation of cardiac metabolism and the inflammatory reaction that is involved in ROS formation.

Impact of aortic stiffness on myocardial ischaemia in non-obstructive coronary artery disease

Objective

High aortic stiffness may reduce myocardial perfusion pressure and contribute to development of myocardial ischaemia. Whether high aortic stiffness is associated with myocardial ischaemia in patients with stable angina and non-obstructive coronary artery disease (CAD) is less explored.

Methods

Aortic stiffness was assessed as carotid-femoral pulse wave velocity (PWV) by applanation tonometry in 125 patients (62±8 years, 58% women) with stable angina and non-obstructive CAD participating in the Myocardial Ischemia in Non-obstructive CAD project. PWV in the highest tertile (>8.7 m/s) was taken as higher aortic stiffness. Stress-induced myocardial ischaemia was detected as delayed myocardial contrast replenishment during stress echocardiography, and the number of left ventricular (LV) segments with delayed contrast replenishment as the extent of ischaemia.

Results

Patients with higher aortic stiffness were older with higher LV mass index and lower prevalence of obesity (all p<0.05), while angina symptoms, sex, prevalence of hypertension, diabetes, smoking or LV ejection fraction did not differ between groups. Stress-induced myocardial ischaemia was more common (73% vs 42%, p=0.001) and the extent of ischaemia was larger (4±3 vs 2±3 LV segments, p=0.005) in patients with higher aortic stiffness. In multivariable logistic regression analysis, higher aortic stiffness was associated with stress-induced myocardial ischaemia independent of other known covariables (OR 4.74 (95% CI 1.51 to 14.93), p=0.008).

Conclusions

In patients with stable angina and non-obstructive CAD, higher aortic stiffness was associated with stress-induced myocardial ischaemia. Consequently, assessment of aortic stiffness may add to the diagnostic evaluation in patients with non-obstructive CAD.

Trial registration number

NCT01853527.