Dr P C Rath, consultant cardiologist at Apollo Hospitals, Hyderabad
Advancement in treatment modalities may help combat the steep rise in CHD-related morbidity and mortality in the country Coronary Heart Disease (CHD) is a growing epidemic in India. According to The Registrar General of India, a whopping 23% of total deaths and 32%of adult deaths in 2010-2013 were ascribed to CHD. Experts suggest that unhealthy lifestyle choice, obesity and at times, a family history of heart disease leads to plaque formation in the coronary artery, causing blockages and restricted oxygen supply to the heart. This manifests in the form of chest pain and in extreme cases, heart attack. The treatment of CHD depends on the accurate assessment of the degree of the blockage.
Coronary artery blockage is treated depending on its severity. Basically, there are three types of treatments –Medical Management, Percutaneous Coronary Intervention (PCI) and Bypass surgery. In PCI, a catheter is used to place a stent (wire mesh tube) to open up blocked arteries and allow free blood flow. In a bypass surgery, blood vessels are taken from other parts of the body, such as the long saphenous vein or the radial artery, and used to bypass the blocked part of the coronary artery. If the blockage is not visually significant then it can be treated with medication, but in the case it is visually significant, PCI or bypass surgery is done. Over the last few decades, interventional cardiologists are widely using PCI for cardiac treatments. To ensure best patient outcomes, it is necessary that PCI is done in an optimal way. PCI optimization means that treatment procedure is done in a way wherein the most appropriate treatment decision is made and there are no post procedure complications. With the advent of latest techniques, the patient prognosis through PCI has improved tremendously. Besides the other prevailing imaging and physiological modalities, advanced technologies like Fractional Flow Reserve (FFR) and Optical Coherence Tomography (OCT) are increasingly becoming important tools in optimizing PCI.
FFR procedure is conducted to rule out the ambiguity in the requirement of stenting. It is a micro sensor based procedure which is conducted to measure the pressure difference across the blocked artery. If the measurement shows a value of less than 0.8, it means that the blockage is significant and requires stenting, while a value of more than 0.8 indicates that the block is not that significant and does not require stenting. Thus, it helps in taking the treatment decision based on the quantitativevalue of the measurement.
The other technique, OCT is a high-definition imaging modality which gives a clear view of the inside of the coronary arteries. Before stenting, this technology helps doctors to comprehend the blockage in detail - assessing the percentage, characteristic and length of the blockage, and most importantly, the diameter of the artery where the stent has to be placed. An evaluation of these aspects further ensures that the size and the length of the stent to be placed are absolutely appropriate. This technique is very useful in post stenting procedure as well. After stent placement, OCT procedure is performed to check if the stent has covered the whole length of the blockage, whether it is properly placed side by side to the artery and ultimately to ensure that there are no complications.
In order to get the best clinical outcomes for patients, PCI optimization is absolutely important. Optimization means that stenting is done in a way that the blockage is fully covered and the resultsare 100 percentfine with minimal risks associated. FFR and OCT have different roles to play in enhancing the efficacy of PCI. While FFR helps in making the best treatment decisionof whether to stent or not, OCT helps in reducing complications in terms of re-blockage and stent thrombosis. Moreover, both these techniques are backed by significant scientific evidence. Clinical trials like FAME I & II demonstrated that when FFR technology is used in the treatment of coronary artery disease, patient outcomes are improved. Two-year results demonstrated that patients who received FFR-guided treatment continued to experience improved outcomes over time, including a 34 percent risk reduction in death or heart attack.Also, findings from the ILUMIEN I, II and III studies showed that OCT can improve preand post-PCI decision making, stent sizing, and placement which results in significantly better stent expansion than angiography-guided PCI, with greater rates of procedural success.
Despite an increase in initial budget, FFR and OCT actually help to reduce the overall cost of heart disease treatment in the long term for the patient. Such technologies always bring clinical and economic benefits, the treating doctors should convey the same so that patients are able to make informed choices.
Using OCT and FFR as a combined technology is ideal for PCI. Knowing which blockage to treat and how to treat it is the crucial factor for optimizing cardiac treatment strategies. Combining the functional modality of Fractional Flow Reserve (FFR) and the anatomical modality of Optical Coherence Tomography (OCT) provides the best insight to a physician to diagnose and treat coronary artery disease in a way which is most beneficial for the patient.