Dr G Sengottuvelu
Senior Interventional Cardiologist
Apollo Hospitals, Chennai
"Beauty is on the eye of the beholder" similarly the severity of blood vessel narrowing as assessed by an angiogram also depends on the eye of the beholder. Unless the narrowing is very severe or very mild the treatment decision taken based on angiogram is as good as taken by tossing a coin. This may result in unnecessary stenting as we have shown in our earlier study by comparing angiographic decision with functional assessment using Fractional Flow Reserve.
Fractional Flow Reserve is an excellent modality to accurately assess the need for stenting of a narrowing in your heart blood vessels. Deposition of cholesterol in the heart blood vessels is called as atherosclerosis which is an aging disease starting as early as ten years of age. So for statistical reasons alone a significant proportion of subjects who undergoes angiogram beyond 45 years is destined to have angiographic narrowing, but all of them do not require stenting or bypass surgery. A positive treadmill test or a stress echo or myocardial perfusion imaging showing reduction in blood flow because of the narrowing is a must before stenting except in sudden heart attack. But in reality only 50% of subjects undergo one such test prior to angiogram and the decision regarding the stenting is left to the operator’s visual assessment that is prone for errors. Even if one such test is done, it’s difficult to take a clear decision in a patient with multi vessel disease or left main disease as none of the above test is lesion specific. In other words none of the above test can clearly say which narrowing is causing the symptom or the positive non-invasive test.
We present two patients we treated recently in a similar complex scenario where decision making based on usual tests would have caused an error. In the first case it would have been an unnecessary procedure and the second case we identified and saved a life by surgery which would have left without surgery based on usual tests. These two patients have been an eye opener even for many physicians as it was the block involving the main vessel and if it occludes the presentation is sudden death.
In the first case, a middle aged lady and mother of a doctor was evaluated elsewhere and adviced bypass surgery with reports showing left main vessel block (with potential for sudden death). We performed pressure measurement across the narrowing using FFR wire and direct visualisation from within the heart blood vessels (maximum 3-4mm in diameter) using sound based ultra-thin catheter system (< 1mm) the Intra vascular ultrasound (IVUS) which showed the blocks were not significant. Based on these bypass surgery was not required and we treated with medicines only says Dr Sengottuvelu. He further added that these hitech tests provide high level of scientific evidence to say bypass surgery is not required when somebody has adviced the same based on regular tests.
In the second case, a middle aged gentleman came with chest pain, a positive nuclear scan showing reduction in blood flow and CT scan showing narrowing. Based on available tests his treatment would have been stenting of the small branch. As we felt the angiogram was not very tight to cause symptoms, we did pressure measurement across the lesion (FFR) that turned out to be normal. Then we checked FFR for the main left blood vessel which is the most important blood vessel as there was mild narrowing by angiogram. Pressure measurement across main vessel was highly significant and we confirmed by direct visualization using IVUS which showed high amount of cholesterol deposition at most critical (origin) part of the main blood vessel of his heart that was missed in all other modalities of investigation. He was advised bypass surgery which he underwent successfully thus avoiding a potential for sudden cardiac death.
Dr Sengottuvelu says that "these two cases have clearly shown the benefits of Hitech tests to identify the best treatment decision with precision”. All anatomical narrowing are not significant physiologically which determines the risk of heart attack and hence the need for stent or bypass”. High degree of expertise combined with the state of the art technology and the thirst for perfection leaving nothing to guess work helps us to practice the most evidence based medicine. He further adds that it is not only the availability of these tests, it is the availability of expertise to perform these hitech tests in these complex situations.