The human heart is a study in efficiency and durability — beating billions of times in a normal lifespan. Still, there are a lot of moving parts, and bad luck or bad habits can throw a wrench into these mechanisms.
Fat, cholesterol and other compounds can block blood vessels, leading to heart attacks. The heart’s electrical system can malfunction, creating a chaotic heartbeat and increasing the risk of stroke. Heart valves that control blood flow can be congenitally malformed or become calcified, limiting their efficiency. Cardiac events, chronic inflammation and other drivers can erode muscle, leading to heart failure.
These issues are fueling a heart disease epidemic. According to the American Heart Association, nearly 130 million Americans have some form of heart disease, and the trend lines aren’t good. By 2050, those numbers are expected to exceed 180 million.
Some of that increase will be due to increased lifespans, because all tissues weaken over time. However, a significant portion will come down to lifestyle — too much unhealthy food, not enough activity.
Regardless of the cause, the cardiovascular specialists at the Miller School of Medicine have built a powerful system to investigate the mechanisms that damage heart health and determine the best approaches to mitigate or even reverse them.
“The University of Miami has been a heart-care pioneer for decades,” said Yiannis Chatzizisis, M.D., Ph.D., professor and chief of the Division of Cardiovascular Medicine. “We have helped lead the way in minimally invasive procedures, heart research, advanced imaging, artificial intelligence and more. Cardiovascular disease can be a killer; we’re here to see that it’s not.”
Keeping Hearts Healthy Sidebars
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Managing Hypertension
We’re making progress in taming a silent killer
Hypertension (high blood pressure) can cause almost everything you don’t want to happen: heart attacks, heart failure, stroke. Worldwide, it is the most common cardiovascular condition, affecting around 1.4 billion people.
Blood pressure is insidious because it’s silent, and it can affect virtually every organ in the body.
“The problem with hypertension is that people often don’t feel it until it’s too late,” said Iliana Hurtado Rendon, M.D., assistant professor of cardiovascular medicine. “If you fall and break a leg, you’re going to have pain, run to the emergency room and take care of it immediately. But people generally don’t know their blood pressure is elevated until they start having heart problems.”
While hypertension is often considered a disease of aging, that’s not always the case. All too often, people in their 20s or 30s are already experiencing hypertension; they just don’t know it.
“Almost nobody is paying attention to their blood pressure when they’re young,” said Maria Delgado-Lelievre, M.D., Residency ’10, assistant professor of clinical medicine and founding director of UHealth’s Comprehensive Hypertension Center, the first American Heart Association–certified center in Florida. “Then, 10 years pass, and they start feeling fatigue or other symptoms. Sometimes they have a heart attack in their 40s or 50s, and it’s only then when they realize they have hypertension.”
As with other cardiovascular conditions, technology is playing a big role in care. Recently, the hypertension center helped test a chest patch that provides blood pressure measurements for 24 hours. With both day and night readings, cardiologists can better understand each patient’s condition.
For patients whose blood pressure is difficult to control, a procedure called renal artery denervation uses ultrasound to ablate nerves that are part of the mechanism that controls blood pressure.
“It’s a very good outpatient procedure with low risk of complications,” Dr. Hurtado Rendon said. “These patients often take four or five medications to control their blood pressure, and we can decrease that, sometimes down to only one.”
Controlling Cholesterol
Reducing lipids may also reduce the risk of dementia
Cholesterol gets a bad rap, but it’s essential for good health; every cell in the body needs it to survive. Still, there can be too much of a good thing, and high cholesterol can increase the risk for heart disease. Fortunately, there are many ways to control cholesterol and other lipids, or fats.
“It’s all about risk,” said Andrew Bromley, M.D., B.S. ’12, a UHealth cardiologist and lipid specialist. “If a patient is deemed to be at high risk for a cardiac event, they would probably benefit from having their risk factors aggressively controlled. That usually involves optimizing blood pressure, lowering blood sugar, and managing cholesterol and other lipids.”
Dr. Bromley and colleagues have significant pharmacological resources to keep cholesterol at bay. He described four big classes of cholesterol-lowering medications:
- Statins, which inhibit an enzyme in the liver that helps produce LDL, the so-called “bad” cholesterol
- Ezetimibe, which blocks cholesterol absorption to keep it away from the liver
- Bempedoic acid, which inhibits the liver enzyme ACL, reducing cholesterol synthesis
- PCSK9 inhibitors, which allow more cholesterol to be absorbed from the blood
Statins are often a preferred initial medical therapy because they’re safe and effective, typically lowering cholesterol by 30% to 60%, depending on the drug and dose.
“Statins are incredibly effective at reducing the risk of heart attack or stroke in patients with risk factors for coronary artery disease,” Dr. Bromley said.
The most common side effects of statins are myalgias — muscle aches, nonspecific weakness and some other symptoms. The source of these issues can be a bit confusing since many people on statins are in their 70s and 80s and often have nonspecific muscle issues related to aging.
Some patients are concerned that statins could increase the risk of Alzheimer’s disease and dementia, but the evidence says the opposite. One large study of 104,000 patients found that statins significantly reduced the risk of all types of dementia — a nice extra benefit for patients.
Making Lifestyle Choices
The keys to heart health are sleep, exercise and watching what you put into your mouth
Many people have family histories of cardiovascular disease. While there’s nothing doctors can do about genetic issues yet, there are many ways to control other risk factors.
Patients can modify their heart disease risk by:
- Controlling blood pressure, blood sugar and cholesterol
- Avoiding tobacco and excessive alcohol
- Exercising (moderately) for at least 150 minutes a week
- Controlling stress and anxiety
- Maintaining a healthy body weight
- Getting at least seven hours of quality sleep each night
Dr. Bromley offers some nutritional tips that can also help:
- Don’t overeat, and do try to eat unprocessed, unrefined, natural, real foods as much as possible. The commonsense approach is to stick to the outer edges of the grocery store and avoid the inner aisles where all the processed foods live.
- Eat as plant-based a diet as possible: fruits, vegetables, nuts, grains.
- Your diet doesn’t have to be low-fat, as much as it should be rich in unsaturated and polyunsaturated fats.
- Limit saturated fats from red meats; however, if you’re going to eat a steak, go for the best quality you can afford. Lean, grass-fed red meat is much better than a hot dog.
None of this means you can’t have a hot dog on the Fourth of July. Just make it the exception rather than the rule.
New Guideline for Heart Health
The goal now is to predict disease, not merely measure it
The American College of Cardiology (ACC) and the American Heart Association (AHA) recently issued the first new blood screening guideline in eight years: the 2026 ACC/AHA Guideline on the Management of Dyslipidemia. It includes fundamental changes, moving from a focus on managing cholesterol to looking at abnormal levels of multiple types of lipids or lipoproteins in the blood (dyslipidemias), including cholesterol and triglycerides. All of these can affect cardiovascular health and risks.
“Other than just having a new name, the guideline contains several significant revisions,” said Yiannis Chatzizisis, M.D., professor and chief of the Division of Cardiovascular Medicine. “It focuses on predictors of cardiovascular disease, not just on evidence of disease that is already present. That is why it recommends including Lipoprotein (a) and apolipoprotein B to standard lipid panels to improve risk assessment in certain cases. It also recommends beginning testing much earlier — in adults in their 30s if they have significant familial risk factors.” (Lp(a) — lipoprotein a — and apoB — apolipoprotein B — are two of the heart-health numbers included in the new table.)
The guideline consolidates evidence-based recommendations for managing dyslipidemias into one document, offering a comprehensive strategy for how to best assess and treat various blood lipids to effectively lower an individual’s risk of developing atherosclerotic cardiovascular disease. Caused by a buildup of fatty deposits in the arteries, it is the leading cause of death globally.
“Also, no two patients are alike,” Dr. Chatzizisis said. “The guideline numbers, when combined with other information obtained in an annual physical, such as medical history, diet and physical activity, offer an opportunity to create a precise heart-health plan for each patient.”
Inflammation Detection
Systemic inflammation leads to premature aging from cardiovascular and other diseases
Early in her cardiology career, Claudia Martinez, M.D., a professor of clinical medicine in the Division of Cardiovascular Medicine, was struck by the fact that so many young people living with HIV were having heart attacks. It soon became apparent that the problem was inflammation. Even though their HIV was well-controlled with antiretroviral therapies, the virus was still causing systemic inflammation. As a result, these patients were prematurely manifesting diseases related to aging, such as cardiovascular disease.
“Chronic inflammation affects many of us, regardless of HIV status,” Dr. Martinez said. “High blood pressure, cholesterol, stress, obesity — they all generate inflammation, and that can lead to heart disease. We want to help prevent heart disease, and people with HIV are informing us how chronic inflammation affects the heart.”
Heart disease among people living with HIV can be different in important ways, including affecting more women. It also affects smaller blood vessels, which can complicate treatment. (Large arteries are more amenable to cardiac catheterization and other interventions.)
This makes early detection even more essential. Dr. Martinez and colleagues received a four-year, $2.8 million grant from the National Heart, Lung and Blood Institute to, among other things, investigate inflammatory biomarkers in the blood. She is particularly interested in novel lipid (fat) molecules that contribute to inflammation.
“During COVID, we learned these lipids can be related to acute inflammatory responses,” Dr. Martinez said. “But nobody had ever looked at them in people with HIV.”
This research could produce a number of benefits. The first would be diagnostic understanding of how these inflammatory molecules operate, which could help clinicians recognize which patients are at higher risk for heart disease. On the therapeutic side, dissecting these mechanisms could lead to better treatments to lower those risks.
“We have this great opportunity to go beyond our traditional measures and try to better understand how to prevent, detect and treat heart disease,” Dr. Martinez said. “And this goes well beyond heart disease; cancer, Alzheimer’s [and] so many diseases are driven by inflammation. The more we learn, the better we can manage and prevent them.”
Taking a Closer Look
High-resolution imaging provides additional personalized care
Cardiovascular specialists have always relied on sophisticated imaging to diagnose heart problems and guide them through procedures. Now, advanced imaging techniques, combined with sophisticated artificial intelligence (AI) algorithms, are providing even more information, helping cardiologists and surgeons care for more patients, less invasively.
“We have this unique capability to combine high-resolution imaging of the coronary arteries with information about blood flow and plaque,” Dr. Chatzizisis said. “Imaging gives us the anatomy and the pathology, which allows us to provide the most personalized care.”
The goal is to precisely tailor treatments, such as cholesterol-lowering medications, to match each patient’s disease. For example, a patient who has milder cardiovascular disease, less plaque volume and lower inflammation will need a different care plan than someone with more aggressive disease. AI-interpreted CT scans can drill down further to directly inform which drugs or procedures the patient needs.
In addition, MRIs help diagnose valvular disease and other cardiovascular issues. Importantly, MRI provides extremely precise diagnoses for challenging cardiomyopathies (heart muscle conditions) that previously may have gone undiagnosed and untreated. PET scans can illuminate microvascular (small vessel) diseases, which are quite common in women.
Experts are also using AI to create digital twins — faithful replicas of the coronary arteries and the heart — that they use to plan and simulate procedures. New technologies are also being used to help cardiologists navigate through complex procedures. For example, CT images can be combined with traditional fluoroscopy (real-time X-ray videos).
With a digital view of the anatomy, “it’s much easier to reach challenging places, like the aortic arch, and that’s crucial for complex endovascular aortic reconstructions,” said Jorge Rey, M.D., associate professor of clinical surgery and chief of the Division of Vascular and Endovascular Surgery. “It makes these procedures easier, safer and more precise, with less radiation for patients and clinicians.”
Simulation-guided procedures
Tune in to the “Inside U Miami Medicine” podcast to hear Dr. Chatzizisis’ discussion with Dean Ford
Heart Health By the Numbers
Each of these measurements plays a role in heart health
| MEASUREMENT | YOUR GOAL | WHAT IT TELLS YOU |
|---|---|---|
|
Blood Pressure |
<120/80 |
Force of blood against artery walls |
|
Resting Heart Rate |
50–70 BPM |
Cardiovascular fitness |
|
Oxygen Saturation |
95–100% |
Heart and lung delivery of oxygen to tissues |
|
Carotid Artery Ultrasound |
<125 cm/s |
Peak systolic velocity with no visible plaque |
|
Total Cholesterol |
<200 |
Overall amount of cholesterol in your blood |
|
HDL Cholesterol |
>60 |
Quantity of lipoproteins removing cholesterol from arteries |
|
LDL Cholesterol |
<70 |
Amount of cholesterol in LDL particles in your blood |
|
LDL-P Cholesterol |
<1,000 |
Concentration of LDL particles in your blood |
|
Triglycerides |
<150 |
Amount of fat in your blood |
|
Lp(a) |
<30 |
LDL particles causing plaque buildup and blood clots |
|
ApoB |
<80–90 |
Total number of plaque-forming particles in your blood |
|
hs-CRP |
<1.0 |
Low levels of inflammation in your body |
|
Fasting Glucose Level |
70–90 |
Blood sugar level now |
|
A1C |
<5.7% |
Blood sugar level over 2–3 months |
|
Body Mass Index (BMI) – Weight/Height |
<25% |
Percentage of body fat |
|
Waist Circumference – Men/Women |
<40"/35" |
Amount of visceral fat around internal organs |
Saving Failing Hearts
New drugs and genomic studies offer hope for restoring pumping power
Heart disease is a complex syndrome caused by heart attacks, chronic inflammation, high blood pressure and other issues. The heart loses its ability to effectively pump blood, leaving patients congested, fatigued and often short of breath. Some people can barely walk to the mailbox.
“Heart failure is the end result of a group of cardiovascular disorders,” said Omar Wever-Pinzon, M.D., director of the Advanced Heart Failure Treatment and Recovery Section at the UM/Jackson Health System Miami Transplant Institute. “If a patient doesn’t have good control over their blood pressure, cholesterol or weight, they may eventually experience heart failure. Different pathways can lead to the same destination.”
Heart failure has two distinct types. Heart failure with reduced ejection fraction involves a weakened heart muscle that has trouble pumping blood. In heart failure with preserved ejection fraction, the heart pumps normally, but the left ventricle has trouble filling with blood.
There are numerous ways to treat heart failure with reduced ejection fraction, such as beta blockers, which slow the heart, and SGLT2 inhibitors, which battle neurohormonal changes that further damage the heart beyond the initial insult. These medications help patients live longer and with better quality of life.
There are fewer options for heart failure with preserved ejection fraction, but the Miller School is conducting research, both at the bench and in the clinic, to expand these. For example, the University of Miami is a site for the AURORA-HFpEF trial, which is testing a drug that relaxes the heart.
“Big things are happening in the field,” Dr. Wever-Pinzon said. “Genomic studies help us individualize care, and we are really making progress in understanding the mechanisms that drive heart failure.”
Clearing Clogged Pipes
Better tools are yielding better outcomes
Atherosclerosis, clogging of the arteries, is a potentially deadly condition that is all too common. Injuries to the blood vessels trigger the formation of arterial plaque, made up of cholesterol, calcium, fat and other substances. Over time, these plaques build up and impair blood flow.
“Eventually, the plaque can block the artery and reduce circulation — a condition known as ischemia — to the organ the artery is feeding,” explained Jorge Rey, M.D., associate professor of clinical surgery and chief of the Division of Vascular and Endovascular Surgery.
Surgeons performed the first open heart procedure to bypass these blockages in 1967. Ten years later, the first cardiac catheterization combined with angioplasty used a catheter to thread a balloon to the blockage. Inflating the balloon pushes the plaque aside to restore blood flow. Later, wire cages, called stents, were introduced to keep vessels open, followed by medicated stents to keep them open longer.
“There’s an ongoing technological revolution,” said Aditya Satish Bharadwaj, M.D., who directs UHealth’s Cardiac Catheterization Laboratories. “We’re using the fourth-generation drug-eluting stents, and we have a diamond-tipped rotor tool we can feed through the artery to remove calcified plaque and other techniques. The tools keep getting better and better.”
These advances are particularly welcome for older patients and those dealing with diabetes, obesity and other complicating conditions. Until recently, many of these patients were ineligible for open surgeries, and catheterization couldn’t always handle their complex issues. Temporary, implantable heart pumps and advanced imaging now allow cardiologists to help these patients.
“These pumps have revolutionized our ability to treat patients in the cath lab who we would formerly have shied away from because they were such high risk,” Dr. Bharadwaj said. “And the ability to actually visualize the inside of arteries helps us optimize stent results.”
Technology advancements have also enabled vascular and cardiothoracic surgeons to move away from open surgeries in more situations. They’re embracing minimally invasive techniques for aneurysms and other dire conditions.
“Initially, every single vascular problem was treated with an open procedure if it could be treated at all,” Dr. Rey said. “Now, we always try to use the least invasive technique possible.”
The next wave may be robotic surgery. “One of the downsides of open surgeries is the added complications that come from larger incisions,” Dr. Rey said. “But if we do it robotically, we could minimize some of those complications.”
Restoring the Rhythm
Improved procedures are helping AFib patients
Heartbeats can seem eternal, but for people with atrial fibrillation (AFib), which makes the heart lose its normal rhythm, they aren’t always reliable. And when the heart loses normal rhythm, its top chambers (the atria) start quivering and can no longer effectively move blood into the bottom chambers (the ventricles).
“When the heart is quivering, blood clots can form,” said Raul Mitrani, M.D., professor of cardiovascular medicine. “If these clots get dislodged, they can go to the brain and cause a stroke. Around 25% of all strokes in this country are attributable to atrial fibrillation.”
AFib can affect people who’ve had heart attacks, heart failure or high blood pressure. Patients can feel lightheaded and dizzy, experience chest pain or feel like their hearts are racing. They are often tired and fatigued.
Some individuals with AFib may require blood pressure medication or a GLP-1 drug to lose weight. Blood thinners may be used to reduce the risk of stroke. In some cases, a procedure called an ablation identifies problematic cells and destroys them.
“Atrial fibrillation is like a fire in the atrium; we find the sparks that start the fire and try to eliminate them,” Dr. Mitrani said.
Decoding virtual clinical trials and simulation-guided procedures
Tune in to hear how Dr. Chatzizisis performed the world’s first simulation-guided left main stenting procedure using artificial intelligence, computational simulations and extended reality.
Replacing Damaged Valves
New valves are lasting longer — and so are the patients who receive them
Heart valves have a specific and critical job: keeping blood flowing in the right direction. Diseased valves, whether from calcification, stretching or genetic conditions, can impede forward blood flow or allow blood to leak backwards. Patients experience chest pain, fatigue, shortness of breath and other symptoms of congestive heart failure. The aortic valve is particularly crucial, as it manages blood flow throughout the body.
Like so many other procedures, valve replacement used to require open heart surgery. Transcatheter aortic valve replacement (TAVR), introduced around 20 years ago, made the procedure far less invasive. TAVR uses a catheter, inserted into a blood vessel near the groin, to deliver the replacement valve without the need for general anesthesia.
University of Miami has one of the top TAVR programs in the country. In fact, Miller School cardiologists were among the first to adopt the procedure in 2008. Most patients spend less than 24 hours in the hospital, and readmission rates are negligible.
This quality is driven by skilled clinicians and advanced technology, including artificial intelligence (AI) systems that help cardiologists simulate and plan procedures on an individualized basis.
“Based on the patient’s CT scan, the AI software reconstructs the patient’s aorta, aortic valve and specific anatomy,” explained interventional cardiologist Nikolaos Spilias, M.D., assistant professor of clinical medicine. “We simulate different types of valves and get some very useful information about the most suitable valve, the risks of complications during the procedure, as well as planning of future procedures.”
Most valves usually last around 10 to 12 years, which means that younger patients may need another valve replacement later on.
“For patients with aortic stenosis — narrowing of the aortic valve — we are always thinking about lifetime management,” Dr. Spilias said. “When we have a 70-year-old patient with severe aortic stenosis, we have to think two steps ahead because life expectancy has increased, and they may need another valve in their 80s.”
Artificial valves are a modern miracle, but they’re not for every patient. For children and adults under 60, the prospect of getting a new valve every 10 years or so could be problematic, even dangerous. In those situations, the best choice may be a complex open surgery called a Ross procedure.
“The Ross procedure was originally developed for children who required an aortic valve replacement, and it has since been adapted for adults,” said Juan Pablo Umaña, M.D., chief of the Division of Cardiothoracic Surgery and co-director of UHealth’s new Comprehensive Aortic Program. “We take the pulmonary valve and use it to replace the aortic valve. It’s a living valve, which means it adapts and grows, making it ideal for children and younger adults.”
“We have to stop being short-sighted about shorter hospital stays and faster recovery,” Dr. Umaña said. “With younger patients, we really have to play the long game.”
reengineering the heart
Hear Dr. Umaña share and Dean Ford discuss a bold vision for the future of cardiothoracic surgery
