What is Acute Coronary Syndrome Catheter Interventions?
Acute coronary syndrome (ACS) is a heart condition that doctors often see in hospital patients. It’s a type of heart disease that mainly happens when a fatty deposit, or plaque, inside a heart artery breaks off or gets worn away. This leaves the fatty core exposed to the bloodstream, causing blood platelets and clotting factors to activate and form abrupt blockages in the arteries. Each stage of ACS can be treated in different ways, based on how the patient’s condition presents.
For a long time, the main way doctors treated ACS was by using drugs. This included pills to make the blood less sticky and less likely to clot (antiplatelet and anticoagulation medicines), drugs to reduce chest pain (anti-anginal medications), as well as aggressive therapy to lower cholesterol and other heart disease risk factors. In 1958, the introduction of clot-dissolving drugs, known as thrombolytics, changed how doctors treat ACS.
At first, this approach, which was tested and proven effective in trials such as ISIS, GUSTO, and GISSI, was a successful way to treat emergency blockages of the heart arteries, especially in severe types of heart attack (STEMI). However, even though these drugs improved survival, reduced heart damage, and lowered the risk of complications, they still showed major problems with severe bleeding, including strokes, as well as issues with repeat heart attacks.
The most successful clot-dissolving treatments could only open up the blocked heart arteries in half of the patients within 90 minutes. Five percent of these patients would require a blood transfusion due to bleeding, and 1.8% would suffer a stroke. Despite gradual advances in the management of ACS, outcomes heavily suffered due to these issues. But all this changed dramatically in 1977 when a physician named Andreas Gruentzig developed a groundbreaking way to treat ACS using a procedure called balloon angioplasty. This completely revolutionized the field of cardiology; hence, he is often revered as the father of interventional cardiology.
What Causes Acute Coronary Syndrome Catheter Interventions?
The use of catheter-based treatments started in the late 1970s. These treatments for heart attack-like conditions worked because they could use the bloodstream as a kind of highway to reach and treat heart blockages without the need for open-heart surgery. This technique of getting into the blood vessels and resolving blockages with a catheter completely transformed heart medicine. In 1929, Werner Forssmann first described a cardiac catheter as a plastic tube that allowed for the delivery of medicines or dye for imaging, and for checking the pressure inside the heart. Over time, catheters have evolved from diagnostic tools for measuring pressure to treatment tools, a major development in the late 1970s.
In the 1970s and 1980s, using balloon angioplasty was debated and mainly recommended for stable heart blockages. Patients with heart attack-like conditions still relied on clot-busting drugs and heart bypass surgery for treatment. However, by the late 1990s, Stone, Grines, along with other heart attack researchers, showed that using balloon angioplasty for treating heart attack-like conditions was safe and effective. Their research found that patients treated with balloon angioplasty had a lower death rate in hospital, less recurrence of heart blockages or stroke, and smaller hospital stays, compared to those treated with a clot-busting drug.
In the late 1990s, two more milestone studies were published showing the effectiveness and safety of using a metal scaffold, known as a stent, for implementation in the coronary arteries. These trials found that stents resulted in fewer major heart problems compared to balloon angioplasty. Initially, these stents were bulky and prone to requiring further treatment, and the procedure was coupled with many vascular complications limiting its practicality and widespread use. However, these issues were resolved in the early 2000s with the creation of a new stent design that could release growth-controlling agents. This discovery once again revolutionized heart medicine and changed the way both stable heart disease and heart attack-like conditions were treated. Over time, catheters and their delivery systems have been modified to include more advanced features, such as the ability to deliver stents and balloons, along with fewer major adverse heart events.
Risk Factors and Frequency for Acute Coronary Syndrome Catheter Interventions
Acute coronary syndrome is a major global health issue often leading to severe illness and death. In the United States, it’s estimated that each year sees around 550,000 new cases and over 200,000 recurring cases. The condition primarily affects adults, and more frequently men, with the average age of occurrence being 65 years for men and 72 years for women. The National Cardiovascular Data Registry reports that more than 600,000 interventions to open blocked arteries, called percutaneous coronary interventions, are performed in the U.S. every year. In fact, in 2014, it was reported that 667,424 of these procedures took place in 1,612 hospitals nationwide, with about 64% of these interventions being performed on acute coronary syndrome patients.
Signs and Symptoms of Acute Coronary Syndrome Catheter Interventions
Diagnosing and managing Acute Coronary Syndrome, a condition of sudden reduced blood flow to the heart, relies heavily on understanding the patient’s medical history and conducting a physical exam. Immediate detection of this condition is key to improving the patient’s health outcome. Often, patients report their symptoms to first responders who don’t have access to their medical records, making prompt recognition crucial.
The typical symptoms of Acute Coronary Syndrome can include:
- Chest pain or discomfort that worsens with physical exertion, often lasting less than 30 minutes. The pain is usually felt just under the breastbone and can spread to the abdomen, back, jaw, or arms. It often improves with nitroglycerine and differs from previous chest pain in severity or frequency.
- Shortness of breath, which usually occurs when resting or performing light exercises, and can worsen suddenly.
- Sudden breaks into cold sweats.
- Other non-specific symptoms such as dizziness, abdominal pain, feeling of pins and needles, palpitations, nausea, vomiting, and headaches.
On physical examination, medical practitioners might observe these signs in patients with Acute Coronary Syndrome:
- Increased or decreased heart rate
- High or low blood pressure
- Low oxygen levels in the blood
- Rapid breathing
- New heart sound
- Difficulty breathing while lying flat
- Swelling in the lower extremities
- Engorged veins in the neck
Physical exam results can vary from patient to patient, depending on how far along and severe the disease is. However, a thorough physical examination is recommended for all patients suspected to have Acute Coronary Syndrome and are candidates for catheter-based intervention. Special attention is given to cardiovascular, respiratory, neurologic, and vascular systems, because of the associated risks, such as bleeding, associated with certain medications and procedures.
Allergies must be assiduously assessed before any catheter-based intervention to handle unexpected reactions to medications during or after the procedure, or to the iodinated contrast used for imaging during angiography. Therefore, compiling a detailed history and conducting a thorough physical examination is mandatory before any heart-related procedure using a catheter.
Testing for Acute Coronary Syndrome Catheter Interventions
Before undergoing a cardiac catheterization procedure, patients require thorough evaluation to minimize potential complications. This procedure involves accessing the blood vessels and inserting a thin tube into the heart vessels. During the procedure, the patient will receive substantial doses of anticoagulant and antiplatelet medications, which increase the risk of bleeding. Furthermore, a type of dye called iodinated contrast, used for generating images, can harm the kidneys. Furthermore, patients with larger or more complex heart conditions may also be at risk of specific complications such as heart failure or abnormal heart rhythms. For these reasons, it is crucial to properly assess the patient before the procedure.
Firstly, it is important to continuously monitor the patient’s vital signs, including heart rate, blood pressure, oxygen levels, temperature and breathing rate. These can help indicate any instability in the patient’s condition and potential risk of infection.
Next, a 12-lead electrocardiogram (ECG) should be performed to check the electrical activity of the heart. This test is essential in identifying potential signs of major heart diseases. Changes in the pattern of the ECG can provide important information about the type and severity of the heart condition.
Continuous telemetry, or heart monitoring, is also necessary. This technology provides real-time monitoring of the heart’s rhythm and function, especially for patients with acute coronary syndrome.
Also needed are several lab tests. A complete blood count (CBC) provides a baseline snapshot of blood cells and platelets that can help determine the patient’s risk of bleeding during the procedure. A Basic Metabolic Profile (BMP) is essential to assess kidney function as patients are given medicines during the procedure that may harm the kidneys. Meanwhile, blood coagulation tests like Partial Thromboplastin Time (PTT), Prothrombin Time (PT) and International Normalized Ratio (INR) help evaluate how quickly a patient’s blood clots, enabling appropriate medication dosage. Troponin and CKMB tests can gauge the extent of heart muscle damage prior to the procedure. Though not always needed, Brain Natriuretic Peptide (BNP) can help diagnose heart failure in patients with heart attack.
Imaging tests such as a Chest X-ray may be performed to look for signs of heart failure in the lungs, while CT scans of the chest or the brain might be helpful if other chest conditions or stroke are suspected.
Treatment Options for Acute Coronary Syndrome Catheter Interventions
There are several ways doctors can access the heart’s arteries when dealing with acute coronary syndromes, or heart-related emergencies. Here’s a simplified explanation of some of these approaches:
Transradial: This is the generally preferred method. Doctors gain access to the heart through the radial artery in the right or left arm. A sheath is inserted to maintain access, and then special tubes called catheters are used for diagnosis and treatment. This approach has been found to be safer with less risk of bleeding and complications compared to another approach called transfemoral. However, it can expose both the patient and the doctor to higher levels of radiation.
Transfemoral: In this method, doctors access the heart through the femoral artery in the person’s leg. Some doctors may prefer this method due to less anatomical variations and the possibility for large bore access if needed. However, it has been found to have higher rates of adverse cardiovascular events and significant bleeding. It’s also associated with increased mortality in heart-related emergencies compared to the transradial approach.
Transbrachial and Transulnar: These are less common methods of access that are done via the brachial artery in the arm, and the ulnar artery in the forearm, respectively. They’re not used very often due to potential complications and lack of evidence and experience with these methods.
Distal Radial Access: This is a rare method due to the small size of the vessel and lack of evidence or operator experience. However, if needed, it can potentially be a safer option.
When a doctor gains access to the heart’s arteries, they use specialized instruments, such as wires and different types of catheters. These catheters can be diagnostic, guiding, or balloon types and have different uses, from diagnosis to dilating a narrowed artery or delivering medications. There are also additional therapies and devices like thrombectomy catheters for removing clots, atherectomy catheters for plaque removal, and various imaging catheters for a detailed look at the vessels.
Without getting too technical, it’s important to note that doctors have many tools at their disposal to deal with heart-related emergencies.
What else can Acute Coronary Syndrome Catheter Interventions be?
Acute coronary syndrome, a condition characterized by sudden, reduced blood flow to the heart, might be confused for several other medical conditions including:
- Aortic dissection, where there is a tear in the wall of the aorta
- Acute pulmonary embolism, a condition caused by a blocked blood vessel in the lungs
- Pneumothorax, also called a collapsed lung
- Acute pericarditis, which is inflammation of the covering of the heart
- Myocarditis, inflammation and damage of the heart muscle
- Esophagitis, inflammation of the esophagus
- Esophageal perforation, a hole in the esophagus
- Critical aortic stenosis, a form of heart disease where the aortic valve doesn’t fully open
It’s essential that these possibilities are carefully considered and appropriately tested to ensure correct diagnosis and treatment.
What to expect with Acute Coronary Syndrome Catheter Interventions
Mortality rates for patients with different kinds of heart conditions were recorded in a study called the Global Registry of Acute Coronary Events (GRACE). The six-month mortality rates were roughly 17% for patients with STEMI, a type of heart attack, 13% for patients with NSTEMI ACS, a less severe type of heart attack, and 8% for those with unstable angina, a condition that causes chest pain.
These numbers have been decreasing over time, thanks in large part to advancements in a procedure called percutaneous coronary intervention and increased experience among doctors performing this procedure.
This trend toward lower mortality rates is also a result of more medical facilities adopting another procedure known as transradial PCI. This procedure has shown to further reduce mortality rates in patients with both NSTEMI ACS and STEMI. This is backed by the findings of numerous studies conducted over the past decade, including the MATRIX and STEMI-RADIAL studies.
Possible Complications When Diagnosed with Acute Coronary Syndrome Catheter Interventions
Problems that stem from coronary intervention, a procedure to improve blood flow to the heart, can be minor or major, depending on their impact on the body’s blood flow. The most common issue after a coronary intervention is bleeding at the site where doctors insert the catheter. This typically happens due to the high amount of blood-thinning medication given and sometimes the need for large-sized catheters. This can lead to complications at the access site, such as a hematoma (a solid swelling of clotted blood), pseudoaneurysms (a false aneurysm), or a tear in the blood vessel. These complications often happen when the catheter is inserted through the thigh artery.
Other complications can include kidney damage due to contrast dye, a tear or puncture in the blood vessel, a stroke or other conditions caused by clots or air bubbles traveling to the brain, a heart attack, the need for emergency heart surgery, and in rare cases, death. The chance of these complications occurring can vary depending on the hospital and the surgeon’s experience.
However, even though these potential complications exist, the overall risk involved in the procedure is low (between 1 to 2%), and the benefits of the procedure often outweigh the risks.
Common complications include:
- Bleeding at the catheter access site
- Access site complications
- Kidney damage due to contrast dye
- Tear or puncture in the blood vessel
- Stroke or other clot-related conditions
- Heart attack
- Need for emergency heart surgery
- Rarely, death
Recovery from Acute Coronary Syndrome Catheter Interventions
Patients who have just recovered from an acute coronary syndrome are highly recommended to participate in cardiac rehabilitation. Prior to starting a guided exercise program, patients should undergo functional testing. Usually, patients come in for an outpatient visit 4 to 6 weeks after suffering from acute coronary syndrome. This is to further evaluaye and determine the risk level through a functional testing that includes an exercise stress test. The aim is to let the patient return to their normal activities without limitations.
Additionally, sometimes, patients also have a thorough assessment with vasodilator myocardial perfusion imaging. This usually happens before they are discharged from the hospital, to gauge the need for complete revascularization, especially if there was evidence of diffuse disease on the target vessel revascularization.
Preventing Acute Coronary Syndrome Catheter Interventions
The doctor explains the procedure in this way: a cardiac catheterization is a simple procedure where we check out your heart’s blood vessels using a special dye and an imaging technique called fluoroscopy. Initially, your doctor will access your blood vessels, usually through your wrist’s artery or sometimes through the groin’s main artery. Subsequently, we will use a thin tube (around 2 to 3 mm in thickness) and a wire (around 0.014 to 0.035 mm in diameter) to reach your heart’s arteries. After reaching the arteries, we will capture multiple images to look for any significant blockages.
If we find any blockages, we will go ahead and fix these using tubes known as stents and tiny inflatable devices called balloons. Though generally safe, this procedure carries some risks which include bleeding and infection at the place where we access the artery, discomfort, issues with blood vessels, stroke, heart attack, and in extremely rare scenarios, death. However, the overall risk is quite low (around 1 to 2%), and the benefits of undergoing the procedure are significantly greater than the risk.
