How Hi-Tech Imaging Can Saves Lives!
The severity of a blood vessel narrowing, as assessed by an angiogram depends on what is seen in the X-ray. Unless the narrowing is very severe or very mild the decision about treatment based on an angiogram is as good as a decision, taken by tossing a coin, as this may result in unnecessary stenting. So, comparing an angiographic decision with a functional assessment using a fractional flow reserve, is a more viable option.
Fractional Flow Reserve
Fractional flow reserve (FFR) is an exceptional means of accurate assessment for stenting requirements (when there is narrowing in the blood vessels of heart). Deposition of cholesterol in the blood vessels of the heart is called atherosclerosis, which is an ageing disease starting as early as ten years of age. Statistically, a significant proportion of subjects undergo angiogram beyond 45 years of age and are destined to have angiographic narrowing, but all do not require stenting or a bypass surgery.
Tests Prior To An Angiogram
A positive treadmill test, or a stress echo or myocardial perfusion imaging showing a reduction in the blood flow because of the narrowing, Is a must before stenting, except In case of a sudden heart attack. But in reality, only 50 per cent of subjects undergo one such test prior to an angiogram and the decision regarding the stenting is left up to the operator’s visual assessment that is prone to errors.
Even if one such test is done, it’ difficult to take a clear decision about a patient with multivessel disease or left main disease, as none of the above tests are lesion-specific. In other words, none of the above tests can clearly say which narrowing is causing the symptom or the positive non-invasive test.
Two Case Studies
Here are cases of two patients who were treated recently in a similar complex scenario where the decision making (if) based on usual tests, would have caused an error! In the first case, it would have been an unnecessary procedure and in the second case, the person’s life was saved by a surgery. However, there would not have been any surgery if decisions were based on the usual tests. These two patients’ cases have been an eye-opener for many physicians, as it was the block involving the main vessel and il it had to occlude, there would have been sudden death of the person.
The First Case
In the first case, a middle-aged lady and mother of a doctor was evaluated elsewhere and advised bypass surgery with reports showing left main vessel block (with potential for sudden death). So a pressure measurement across the narrowing using FFR wire was performed and direct visualisation from within the heart blood vessels (maximum 3-4mm in diameter) using sound-based ultra-thin catheter system (<1mm) and the intravascular ultrasound (IVUS) which showed the blocks were not significant.
So based on these reports, bypass surgery was not required and treatment was carried out with medicines alone, as these hi-tech tests provide a high level of scientific evidence to ascertain bypass surgery is not required, even if advised on the basis of regular tests.
The Second Case
In the second case, a middle-aged gentleman came to the hospital with the complaint of chest pain, a positive nuclear scan showing reduction in the blood flow and a CT scan showing narrowing. Based on the available tests, his treatment would have been stenting of the small branch. But since the angiogram was not considered accurate to cause the symptoms, pressure measurement across the lesion (FFR) was performed, which turned out to be normal.
Later on, FFR for the main left blood vessel (the most important blood vessel) was checked as there was mild narrowing according to the angiogram. Pressure measurement across the main vessel was highly significant and confirmed through direct visualization (using IVUS), a high amount of cholesterol deposition at the 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 the potential of sudden cardiac death.
Statistically, a significant proportion of subjects undergo angiogram beyond 45 years of age and are destined to have angiographic narrowing, but all do not require stenting or a bypass surgery
Conclusion
These two cases clearly demonstrate the benefits of hi-tech tests to identify the best treatment decision with precision. Thus, a high degree of expertise combined with state-of-the-art technology and the thirst for perfection, leaving nothing to guesswork, helps doctors practice the most evidence-based medicine. Also, it is not just the availability of these tests that is crucial, it is also the availability of expertise to perform these hi-tech tests, in these complex situations that Is very important.