Imaging the Coronary Arteries : a brief account. Asif Adnan Clinical Research Fellow Dept. of Cardiovascular Sciences University of Leicester

Transcription

1 Imaging the Coronary Arteries : a brief account Asif Adnan Clinical Research Fellow Dept. of Cardiovascular Sciences University of Leicester

2 Outline History of Cardiac catheterization and development of coronary angiography Role of other modalities in imaging the coronaries A few words on post mortem imaging of the coronaries

3 First record of cardiac catheterization: 1711

4 Werner Forssmann and cardio-radiogrpahy :1929

5 The early days of cardiac catheterization: Hemodynamic monitoring of RV and LV

6 We have killed him!! the journey into forbidden territory : Mason Sones,

7 The era of selective coronary angiography Pioneered by Mason Sones Further development by Judkin s and Amplatz with pre-shaped catheter Procedure became simpler, easier and widely used

8 Modern coronary angiography

9 The advantages and limitations of invasive angiography High spatial and temporal resolution Real time image of the coronary arteries Diagnosis and intervention can be performed in the same setting

10 Coronary angiography followed by primary angioplasty in a patient with inferior STEMI

11 Limitations Invasive procedure (major complication rate <1:1000) Exposure to radiation ( but the dose is very small 1 msv) Two dimensional imaging of a three dimensional structure- requires multiple views from different angles Requires specialists team and equipment Only provides information on luminal narrowing (essentially a luminogram ) and not the vessel wall and hence no idea about the overall burden of atherosclerosis

12 The question of functional significance of a stenosis : FFR (Fractional Flow Reserve)

13 The modern intravascular imaging IVUS Intravascular Ultrasound VH-IVUS- Virtual Histology with IVUS OCT Optical Coherence Tomography NIRS Near Infra Red Spectroscopy

14 Comparison of Histology and IVUS

15 VH-IVUS : Virtual Histology with IVUS

16 Clinical example of coronary OCT A B C Optical coherence tomography (OCT) images of intact atherosclerotic coronary plaques. Panel A: shows a normal looking vessel wall. Panel B: depicts a red thrombus inside the lumen. Its OCT signature is the shadowing behind the mass (asterisk). Panel C: illustrates a ruptured plaque. Garcia-Garcia et el. Heart 2009;95:

17 Assessment of coronary intervention using OCT Figure 4 Assessment of intervention results immediately post-stent deployment. The cross-sections shows several points of mild tissue prolapse (asterisk) and incomplete stent apposition in the right lower quadrant. The measured strut vessel distance was 450 mm (strut thickness ¼ 81 mm). Garcia-Garcia et el. Heart 2009;95:

18 Advanced OCT image analysis : OCT as true virtual histology Fig. 5. (a) H&E and (c) CD68 stained histology image of a cross section. OCT and attenuation images of the cross section before (b) and after (d) fixation. The arrows indicate a streak of macrophages in the intima overlying a lipid pool. Additionally, luminal macrophage are evident on CD68 staining (arrowheads) with associated attenuation. Gnanadesigan et el. Biomedical Optics Express, April 2014, Vol. 5 (4)

19 Mild to moderate plaque with calcification

20 Role of non-invasive imaging in coronary artery disease Ultrasound CT MRI

21 CT coronary angiography showing a stenosis of the Left Anterior Descending Coronary Artery

22 Advantages of CT Non-invasive Excellent tool for assessing both the vessel wall and the lumen Comparable radiation dose in modern machine and protocols Can be performed in any CT department with limited training Excellent for identifying anomalous vessels and bypass grafts which are often not found easily during invasive angiography

23 Disadvantages Both spatial and temporal resolution are still inferior to invasive angiography Requires much larger contrast dose with potentially higher risk of nephropathy Poor performance in case of calcified lesions and patients with previous stents

24 Can anatomy predict function?

25 Future directions Angiography Plaque analysis CFD to predict functional significance

26 The state of autopsy in the UK Routine (!) case - >90% Medico-legal Consent Coroner s PM (To establish PROBABLE cause of unexpected natural deaths) Autopsy (120,000 + /Year ; 22% of all deaths) (90-95 % of cases) Hospital PM Forensic(homicide, suicide, accidents, other suspicious death etc.) For better understanding of disease process Consent A report of the National Confidential Enquiry into Patient Outcome and Death (NCPEOD, 2006 )

27 Problems with conventional autopsy Heterogeneous Time consuming Cultural and religious objections The process is destructive in nature leading to poor scope of record keeping No options for auditing and improvement Often fails to be conclusive

28 Usual method: Serial cross section of the major epicardial arteries Subject to heterogeneity Inherent error in the process Visual assessment of non-perfused collapsed vessels Invasive C S Champ and S B Coghill, J Clin Pathol :

29 Minimally invasive Autopsy : PMCTA Advantages Disadvantages Non-invasive Reasonable cost and time involvement More acceptable Semi-quantitative Excellent for auditing and training Calcifications Emphasis on severity of stenosis Low resolution for differentiating acute/ culprit lesions Modest specificity and sensitivity

30 Targeted PMCTA (Post mortem computed tomographic angiography): Left anterior descending coronary artery

31 Potential for improvement in the area of minimally invasive Autopsy Higher Resolution Higher specificity for culprit lesion identification Adding a paradigm of functional severity Coronary Optical Coherence Tomography (OCT) can potentially achieve all of the above as an adjunct to PMCTA

32 QAngioCT Re :Contrast-filled straightened MPR of quantified LAD

33 3D visualization of the complete tree 33

34 Matching LAD of the CTA with two OCT pullbacks 34

35 Surface mesh of the lumen for CFD calculations 35

36 Development of flow simulation using in-house expertise and software Pathlines coloured by velocity magnitude (m/sec)

37

38 Coronary artery imaging is evolving with clinical need and advent of modern technology Invasive coronary angiography still remains the gold standard but the grounds are shifting for the greater good Modern imaging has a huge potential to challenge, modify and improve Autopsy practice and to create a feedback loop which can drive further improvement in research and clinical practice.

39 References for the history of Angiography and cardiac catheterization [1] J. V. Warren, Fifty years of invasive cardiology, Am. J. Med. 69 (1980) doi: / (80) [2] T.J. Ryan, The coronary angiogram and its seminal contributions to cardiovascular medicine over five decades, Circulation. 106 (2002) doi: /01.cir d4. [3] N.J. Mehta, I. a Khan, Cardiology s 10 greatest discoveries of the 20th century., Tex. Heart Inst. J. 29 (2002) [4] R.L. Mueller, T. a Sanborn, The history of interventional cardiology: cardiac catheterization, angioplasty, and related interventions., Am. Heart J. 129 (1995) doi: / (95) [5] F.M. Sones, S. Physician, Coronary Arteriography : Past, Present, and Future, (1962) [6] R. Forssmann-Falck, Werner Forssmann: a pioneer of cardiology., Am. J. Cardiol. 79 (1997) doi: /s (96)

40 Thank you