Why FFR-Guided Revascularization Strategy Is More Effective?

Coronary Artery Disease (CAD) or Coronary Heart disease is a serious heart condition that occurs as a result of atherosclerosis. Hardening or narrowing of the artery (stenosis) causes an obstruction in the blood flow to the heart which may lead to major cardiovascular events. When the heart muscle is starved of oxygen, it results in acute chest pain and discomfort (angina) whereas heart attack (myocardial infarction) is the outcome of a completely blocked blood flow through a coronary artery. Hence, it is important to diagnose and treat coronary heart disease as early as possible, as time plays a crucial role here. Plaque build-ups along the inner walls of blood vessels can cause blockage in either single or multiple coronary arteries. Multi vessel disease (MVD) or Multi vessel CAD is the condition where a major epicardial vessel is affected with 70% or greater stenosis and other major vessels are affected with 50% or greater stenosis.  

Medical therapy, Percutaneous Coronary Intervention (angioplasty and stenting) and Coronary Artery Bypass Grafting (CABG) are the treatment options available for coronary heart disease. Interventional cardiologists used to rely on angiography results and other clinical information to detect the evidence of inducible ischemia and guide treatment decisions. Notwithstanding coronary angiography is considered as the gold standard for CAD evaluation, it has been recognised to have several limitations in assessing the functional significance of coronary lesions. In the case of multi vessel coronary disease, the decision-making is far more challenging as angiographic data tend to either overestimate or underestimate the functional severity of stenosis. Revascularization of non-ischemic lesions not only increases the treatment costs but also poses an increased risk for the CAD patient rather than offering any benefit. That is when the results published by the FAME (Fractional Flow Flow Reserve versus Angiography in Multivessel Evaluation) study gained substantial interest in the medical community. It demonstrated that FFR-guided PCI can ensure better outcomes when compared to the angiography-guided PCI.

Fractional Flow Reserve (FFR) measurements can be taken easily during the invasive procedure just before the stenting. A 0.75 cut-off value helps in differentiating between ischemic and non ischemic stenosis. Lesions with a FFR value of less than 0.75 needs drug-eluting stents (DES) while lesions with a FFR value greater than 0.80 should be treated with medical therapy. The FAME study results proved that routine measurements of FFR during PCI significantly reduced the occurrence of myocardial infarction (MI), combined end point of death and repeat revascularization. So it can be hypothesised that FFR measurements are helpful in guiding decisions regarding whether CABG, stenting or medical therapy would be the optimal approach for each CAD patient.

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Why Timely Coronary Artery Disease Treatment is Crucial?

Heart muscle needs oxygen and nutrient rich blood to function properly and it is supplied by coronary arteries. When healthy, the coronary arteries remain strong, elastic and flexible which ensures the blood flow without any restrictions. However, the arterial health is compromised in some situations because of an underlying pathologic process called atherosclerosis which results in the thickening, loss of elasticity and calcification of coronary arteries. So build up of plaques in the coronary arteries coronary artery stenosis obstructs the blood flow to the heart, thereby weakening or damaging the heart muscles and this condition is termed as coronary heart disease or coronary artery stenosis disease (CAD). Whenever there is a partial blockage in blood supply, it leads to angina (chest pain or discomfort), while a complete blockage of blood flow causes myocardial infarction (heart attack).

Coronary Artery Disease treatment mainly includes medications, procedures and surgeries. Even some lifestyle changes can improve the quality of life. Medications are prescribed to treat the risk factors such as blood pressures, diabetes or high cholesterol levels so that it prevents the CAD from getting worse. Surgical options include angioplasty and stenting (Percutaneous Coronary Intervention) or coronary artery disease treatment or Bypass Grafting (CABG). Depending on the severity of coronary lesions, an appropriate treatment plan is chosen by the cardiologist. Several advanced catheterization procedures and imaging techniques guide the interventional cardiologists to assess the physiological significance of lesions. Angiography, Fractional Flow Reserve (FFR), Intra Vascular Ultrasound (IVUS) and Optical Coherence Tomography (OCT) are some of the indispensable tools used in the catheterization laboratory.

Another heart disease that has gained considerable interest in the medical community is coronary microvascular disease (CMD), which particularly occurs in women. Damage or inflammation of the inner walls of the heart’s tiny arteries is the cause of CMD. Though the presence of this dysfunction can have prognostic implications in many heart vv diseases, there are no reliable standard tests available to detect this micrhovascular disease. Diagnostic techniques developed for CAD can’t be used to assess the microvasculature of the myocardium. For now, index of microvascular resistance (IMR) is a method to investigate the microvascular integrity and functional status of micro circulation. So, FFR and IMR measurements taken simultaneously during the catheterization can help in assessing the coronary artery disease and coronary microvascular resistance disease.

Refer Here: http://continuing-training.blogspot.com/2014/11/Index-of-Microvascular-Resistance.html

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Stenting and Bypass Surgery for Patients with Left Main Coronary Artery Disease

The heart is a fist-sized powerhouse that pumps oxygen and nutrient-rich blood throughout the body to keep us alive. Aorta that bifurcate into two major coronary arteries – Left Main Coronary Artery (LMCA) and Right Coronary Artery (RCA) supply blood to the heart tissues keeping them nourished so that they can function perfectly. Left Coronary Artery also known as Left main stem coronary artery (LMS) branches into Left Anterior Descending Artery (LAD) and Left Circumflex Artery that supplies the left side of the heart muscles and front of the septum with blood. While the Right Coronary Artery divides into the Right Marginal Artery and Posterior Descending Artery which supplies blood to the right side of the heart and sinoatrial nodes. Hence, any blockage in the coronary arteries will disrupt or cut off the blood flow to the heart muscles (myocardium), resulting in its damage or death. 

Plaque that builds up in the coronary arteries as a result of atherosclerotic condition is the major cause  of restricted blood flow. Coronary arterial stenosis of greater than or equal to 50% narrowing is associated with multivessel disease and is termed as the significant left main disease (LMD). Patients with coronary heart disease often suffer from severe chest pain and discomfort as the heart becomes starved of oxygen and nutrients.  In some cases, whenever there is a clogging in the right or left main coronary artery, the collateral vessels become active, and bypassing the blockage they serve as alternative conduits for blood flow. However, it is not a cure or standard medical care option to rely on the functioning of collateral arteries. 

Medical therapy and surgical revascularization (Coronary Artery Bypass Graft Surgery and Percutaneous Coronary Intervention) are the main options available for treating coronary arterial stenosis. Medical therapy was not proven beneficial  for treating LMD as the survival rates were far below.  Performing bare-metal stenting often ended up in higher restenosis rates, acute thrombosis and repeat revascularization. Hence, Bypass surgery (CABG) turned out to be the standard of care for left main disease as it improves the likelihood of survival. 

 

However, advancements in catheterization and medical imaging techniques such as FFR and Optical Coherence Tomography (OCT) have led to the resurgence of interest in Percutaneous coronary Intervention (PCI). Providing a detailed and clear visualization of coronary morphology, OCT has evolved as an indispensable tool for developing new types of coronary stents. Optical Coherence Tomography when used as a guide for coronary interventions ensures better outcomes. Even though, CABG remains to be the superior choice for treating left main CAD, cardiologists hope that the ongoing studies and trials may bring more light into the role of percutaneous approach in near future.

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Treatment of Coronary Artery Stenosis

We have been hearing a lot about the rapid advancements and changes in the field of medical technology ranging from patient registration to data assessment and diagnostic methods to surgical procedures. Yet, some diseases continue to remain as a dreadful term for us; heart disease is a case in point. Coronary Heart Disease (CAD) also known as Coronary Artery Disease (CAD) is the most common type of heart disease that kills more people than any other disease across the world. The main cause of CAD is atherosclerosis (hardening of arteries). Build-up of calcium and cholesterol on the walls of coronary arteries cut down the blood supply to the heart muscles, thereby leading into cardiac ischemia or myocardial infarction (heart attack) among CAD patients.

Severe chest pain or discomfort, also termed as angina pectoris is one of the major coronary heart disease symptoms. The pain can be localised to shoulders, arms, neck, jaw or back. Though, in some cases people also experience nausea, shortness of breath and dizziness. The sensation of discomfort experienced during myocardial ischemia or myocardial infarction develops as a result of coronary artery stenosis. As the degree of coronary artery stenosis increases, myocardial blood flow is reduced resulting in severe chest pain.

Treatment plans differ according to the types of angina, which includes stable angina, unstable angina (UA), variant angina and microvascular angina. When stable angina follows a regular pattern, UA typically occurs when a person is at rest which demonstrates its highest unpredictability and risky nature. On the other hand, variant angina is a rare kind induced due to spasm in the coronary artery and can be treated with medical therapy. Severe pain persists for a long time when it comes to microvascular angina. Patients admitted with coronary heart disease symptoms are advised to undergo different laboratory tests and imaging studies to devise a treatment plan.  

Surgical intervention or medical therapy is the preferred treatment approach to tackle coronary artery stenosis. However, interventional cardiologists find it challenging to deal with coronary bifurcation lesions (a lesion in the parent coronary artery very close or involving a significant side branch) that increases the procedural complexity. An optimal surgical or medical approach for managing coronary artery bifurcation lesions is still on debate as it involves restoring lumen of both the vessels. Time is the main factor in managing angina; hence it is essential to make a quick and safe decision based on the results.

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Fractional Flow Reserve Measurement and Optical Coherence Tomography in Guiding Coronary Interventions

Blockage of oxygen-rich blood supply to the heart due to the plaque build-up in coronary arteries is the primary cause for heart attacks. Termed as Coronary Artery Disease (CAD), this heart problem occurs due to a condition called atherosclerosis.  In some cases, plaque build-up is not just limited within a single epicardial vessel but to multiple vessels known as Multi vessel CAD or coronary multivessel disease. If defined in medical terms - "a condition where 70% or greater stenosis is affected in at least one major epicardial vessel and 50% or greater stenosis is affected in at least other major vessels".

Though coronary angiography has been considered as the ‘gold standard’ for diagnosing ischemic heart conditions, it has many limitations. It often failed in providing comprehensive and accurate information about the physiological significance of lesions. That is when the well-validated Fractional Flow Reserve measurement came into the limelight. Performed along with the cardiac angiogram, it has been proved as a safe and reliable diagnostic tool to differentiate between ischemic and non-ischemic stenosis.

On the other hand, medical imaging techniques such as Intra Vascular Ultra Sound (IVUS) and Optical Coherence Tomography (OCT) have found a place in interventional cardiology. Functional severity of stenosis, plaque morphology and intraluminal coronary dimensions are some of the many features that can be assessed with IVUS.  Whereas, OCT is slightly more efficient than the IVUS technique as it offers microscopic visualization of ten-times higher resolution. Advanced Optical Coherence Tomography technique renders clear and detailed pathophysiology of atherosclerotic plaque. 

In terms of treatment choices for multivessel diseases, we presently have surgical management and medical therapy. Revascularization methods include Percutaneous Coronary Intervention (PCI) or angioplasty and Coronary Artery Bypass Graft (CABG) or bypass surgery. Reliable Fractional Flow Reserve Measurement value along with angiographic data helps physicians decide between PCI and medical therapy for single vessel CAD. Negating the need of repeated revascularization and relieving the likelihood of angina to a greater extent, CABG appears to be a superior choice over PCI when it is concerns treating multivessel disease. However, with the advancements in catheterization, medical imaging and stenting techniques, physicians are shifting away from the aggressive bypass surgical procedures and opting for less-invasive percutaneous treatments that ensure favourable long-term outcome. Yet, the optical treatment strategy for multi vessel CAD remains a controversial topic.

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