Interventional Cardiologist of Apollo Hospitals Dr G Sengottuvelu’ s case study published in Journal of American college of cardiology shows “ new findings in healing heart blocks seen by advanced imaging techniques”.
Chennai, September 2014: Interventional Cardiologist Dr G Sengottuvelu recently published interesting new finding in the May 2014 issue in Journal of American College of Cardiology. A middle aged woman presented with Chest pain and underwent Coronary Angiogram which showed only mild blockage in one of the blood vessel supplying the heart. As this lady was a diabetic and had chest pain we decided to investigate further with two tests, one based on physiology -FFR and other imaging -OCT (like photography within the blood vessel).
“Fractional flow reserve,” or FFR technology provides in-depth measurements of blood flow and pressure in the vessels to the heart which helps us to decide whether the block has to be treated with medicines or whether it requires a stent said Dr G Sengottuvelu. It involves inserting a coronary pressure guidewire into the artery instead of relying solely on the traditional coronary angiogram to determine which arteries should be stented for patients with coronary artery disease. This scientific and evidence based procedure is beneficial to the patient as FFR technology not only saves lives while avoiding unnecessary surgery but also helps patients to save cost.” The FFR is defined as the ratio between distal heart blood vessel pressure and aortic pressure, both measured simultaneously at maximal flow using a tiny coronary pressure guide wire.
Using this FFR technology Dr.Sengottuvelu identified the significant pressure difference for this female patient and which alerted that the block was more severe than was seen by the angiogram. It was puzzling as the block was shown as only mild by Angiography.
Therefore this lady was subjected to another newer Imaging Technique called OCT – Optical Coherence tomography which is a light based catheter which acquires on Image (Photo) inside the heart blood vessel. OCT is a recently-developed, catheter-based intravascular imaging technology that provides micron-scale resolution. It is the laser light equivalent of ultrasound imaging, measuring the intensity of backscattered infrared light rather than sound waves, and translates these optical echoes into a high-resolution, two-dimensional tomographic image. OCT has the highest imaging resolution of any currently-available technology. Cross-sectional resolutions of catheter-based OCT systems are in the range of 10–20 µm.
OCT Image acquisition showed severely blocked artery which was spontaneously (natural mechanisms) opened with small minute channels which were multiple. This was a surprise and new finding not reported in the world and was hence reported in the American Journal said Dr.Sengottuvelu, Senior Cardiologist, Apollo Hospitals.
As the new finding can be explained as the dye given during angiogram passing through these multiple channels within the block, may mask the severity of the block and show it as mild in the angiogram. The r pressure technique of FFR and the light based imaging technique (OCT) helped to unmask the mystery within the block.
Once the block was identified patient underwent Angioplasty and stenting successfully. OCT Imaging was repeated which showed good positioning of stent within the vessel and the block were cleared.
This lady was discharged on the 3rd day and is doing very well on follow up.
Dr.Sengottuvelu highlights that this unique finding of multiple channels in the block was identified because of the availability of the two advanced physiological (FFR) and Imaging (OCT) technology which helped to unravel the mystery.
The acceptance of this finding in the prestigious “Journal of American College of Cardiology “ (Impact Factor of 14) speaks of this unique finding identified using the advanced technology said Dr.Sengottuvelu.
Dr. G. Sengottuvelu, senior consultant interventional cardiologist, one of the high volume operators of Imaging technology says,” I have been using FFR and intra coronary imaging for the past 2 years and found it extremely useful. It is relatively easy to use, readily available in the cathlab and has tremendous utility with lots of scientific evidence backing its use. Nowadays almost every alternate PCI is FFR or imaging guided in my practice as the procedure is quick and easy to perform”.
It’s high time to move beyond the conventional coronary angiogram said Dr Sengottuvelu. Conventionally the coronary arterial narrowing is studied by selectively injecting iodinated contrast agents into the coronary artery and taking fluoroscopic cine pictures. The contrast replacing the blood within the coronary artery produces a two dimensional picture of the coronary lumen – the luminogram. Areas where there is a narrowing in the luminogram in relation to a reference normal vessel are considered to be stenosis and based on its severity it is graded into significant and insignificant stenosis. This grading is conventionally done by visual assessment and hence prone to high degree of inter observer variation and errors especially with lesions in the borderline range (50-70% narrowing). Moreover this luminogram being a two dimensional representation of a three dimensional coronary artery it is prone for over estimation and under estimation of eccentric and recanalized lesions. Here we present a case example where an angiographically insignificant lesion was actually critically narrowed that could have led to another heart attack if not correctly picked up. Thanks to the advanced technologies and expertise available at Apollo Hospitals, Chennai we were able to provide the most appropriate evidence based treatment to the patient. Also this case was one of the best illustrations available in the literature to explain the limitations of the conventional angiogram that we got published in a renowned international journal (JACC).