Coronary Microvascular Disease Program
Nonobstructive coronary artery disease (NOCAD, defined as <50% angiographic stenosis) is a frequent finding during clinically indicated coronary angiogram (CAG) in patients with angina and/or abnormal stress test. In fact, up to 50% [CAD: Patel MR; NEJM 2010] of patients referred for a clinically indicated CAG are found to have NOCAD, one third of men have NOCAD and two thirds of women have NOCAD. [Jespersen L; Eur Heart J. 2012]. Angina and ischemia in these patients are usually termed angina with nonobstructive coronary arteries (ANOCA) and ischemia with nonobstructive coronary arteries arteries (INOCA). Coronary microvascular dysfunction (CMD), usually diagnosed through a coronary reactivity testing (CRT) is usually found in up to 65% of patients with ANOCA and INOCA (Sara J), and in 71% of patients with myocardial infarction with nonobstructive coronary arteries (MINOCA, Raphael C). CRT can identity impaired micro vessel dilation and increased resistance (reduced coronary flow reserve and/or increased index of microvascular resistance) and/or endothelial dysfunction (abnormal lining of heart vessels) and vasospasm of large or small vessels of the heart. Patients with ANOCA, INOCA, and MINOCA often have one or a combination of abnormalities in small vessel resistance, and/or spasm in big or small vessels of the heart causing chest pain.
Importantly, a negative noninvasive stress test does not rule out coronary vasomotor dysfunction in symptomatic patients with NOCAD. This underscores the need for catheter-based gold standard invasive assessment. [Cassar A; Circ: Cardiovsc. Interv. 2009] CMD is associated with a poor prognosis in both men and women [Murthy V; Circulation. 2014] with a 4x increased risk of death and 5x increased risk of major adverse cardiac events (MACE). [Gdowski MA; J Am Heart Assoc. 2020] in addition, microvascular endothelial dysfunction is a threat to vital organ function affecting the heart and beyond. If not identified & promptly treated adverse events that ultimately occur include: microvascular angina, heart failure with preserved ejection fraction, increased risk for major adverse cardiovascular events, vascular neuropathy, thromboembolism in antiphospholipid syndrome, cerebrovascular accidents (transient ischemic accidents, ischemic & hemorrhagic strokes), cognitive decline, lacunar infarcts, retinopathy, and systemic microvascular dysfunction. [Corban MT; Eur Heart J. 2018].
Once CMD is diagnosed followed by initiation of treatment, there are benefits for the patient as well as the medical ecosystem. Evaluation and treatment of microvascular and/or endothelial dysfunction improves angina and quality of life in ANOCA and INOCA patients. Moreover, these patients will experience a sense of valisation, satisfaction, an improvement in their mental health [Reriani M et al; Open Heart 2019]. Ahamad and Corban et al. in 2023 demonstrated the use of CRT was associated with lower health care costs. This study showed an average savings of 25,000.00 USD per patient over 2 years, encompassing utilization of hospital services, imaging costs, procedure costs, and evaluation/management by numerous specialists/cardiologists. [Ahmad A, Corban MT et al. Circ Cardiovasc Interv 2023]
Given all of the above, Dr Michel Corban started the cutting edge CMD CRT program at BUMCT in May 2022. Dr Corban trained to perform these procedures at Mayo Clinic in Rochester and brought the program to Tucson. This program was the first, and remains the only program to date in the entire state of Arizona, to definitively diagnose and treat CMD and coronary endothelial dysfunction in patients with ANOCA, INOCA and MINOCA. Patients have been referred to evaluation and management from all over the state, from Sedona to Sierra Vista. On average, 3 cases of CRT are performed per week (10-12 cases per month). This program has helped add BUMCT to the list of only a handful programs in the nations, most restricted to large academic centers. This program is also an unparalleled opportunity for our interventional cardiology fellows to train on performing these procedures, an experience that they will not have anywhere else in the state. In addition to the clinical importance of this program, 2 research registries have been started collecting valuable information on these patients and numerous abstracts have been presented at national meetings showcasing our cutting edge science related to CMD and coronary endothelial dysfunction. Multiple papers are also currently being finalized for submission.
We certainly envision continued growth of the CMD program along with opening a separate complex chest pain clinic for these patients who have normally seen multiple cardiologists and have undergone numerous stress tests and CAGs before finally undergoing CRT and getting a definitive diagnosis, validation and treatment at our institution.
The future vision is to provide 360-degree care by providers with a passion for CMD (Cardiologists, NPs, Internal Medicine). Once identified by our cardiologists and/or referred to our complex chest pain clinic from the community, these patients can then undergo CRT in the catheterization lab. Once testing is completed and diagnosis is made, the patients will then be referred back to complex chest pain clinic where they will be followed on a long-term basis. With the help and support of the Medicine Department Chair Dr Liao, Cardiology Division Chair Dr Sadek, and Banner Tucson CEO Ms Allison Gafney, combined with the relentless work and passion of Dr Corban and our amazing cath lab and clinic teams, we are hopeful that we will reach unprecedented new heights with this program at Banner University Medical Center Tucson, and eventually extend it to Banner University Medical Center Phoenix!