Presentation on theme: "Radial pulse analysis, central blood pressure and cardiovascular health: an historical curiosity makes a comeback. Tom Archer, MD, MBA UCSD Anesthesiology."— Presentation transcript:
Radial pulse analysis, central blood pressure and cardiovascular health: an historical curiosity makes a comeback. Tom Archer, MD, MBA UCSD Anesthesiology May 9, 2011
http://www.itmonline.org/image/pulse2.jpg Pulse analysis was practiced in Chinese medicine thousands of years ago.
Pulse analysis was also serious business in the 19 th century in Europe and the USA Sphygmographs in common use. Insurance companies relied on their results.
http://www.mamweb.org/modules.php?name=Content&pa=showpage&pid=32000 Etienne-Jules Marey (1830-1904) invented the sphygmograph to record the arterial pulse on smoked paper. It was used by Engelmann, Mackenzie and Wenckebach. Sphygmograph 1876
Life insurance examination manual from 1891 discussed pulse analysis by sphygmography.
Tom Archer, 58 y.o., good general health. Takes Crestor for high cholesterol. Radial and predicted ascending aortic pressure waveform when subject is cold.
Scipione Riva- Rocci introduced the mercury sphygmo- manometer in 1896. Measured systolic BP only.
history.library.ucsf.edu/.../chapter2_03.html Harvey Cushing used it. Korotkoff introduced auscultation for diastolic pressure in 1905.
In the 20th century, Riva-Rocci and Korotkoffs sphygmomanometer eclipsed pulse analysis Two simple numbers: systolic / diastolic. Easy to use. Pulse analysis fell into disuse. 20 th century saw tremendous gains from simple sphygmomanometry: dangers of high BP.
But simple sphygmomanometry ignores valuable information within the pulse trace. Extra information can be extracted from the pulse using high fidelity transducers, computers and a generalized transfer function, which has been validated. Specifically, the Central Blood Pressure (CBP) can be calculated using the radial pulse contour and the non- invasive brachial blood pressure. CBP is the pressure in the ascending aorta.
health.yahoo.com/topic/heart/overview/article... LV sees the SBP in the ascending aorta. With normal aortic valve, LV wall tension depends on pressure in ascending aorta (and diameter of LV chamber).
SphygmoCor system for measuring central blood pressures
Central blood pressure (CBP) Diastolic and mean pressures are very similar at radial / brachial and central sites, but Systolic CBP is not the same as brachial or radial systolic BP!
AIR BLOOD #3 Systemic vascular resistance (resistance arterioles) #2 Stiffness of aorta (windkessel) heart veins arteries #1 SV #4 Wave reflection– timing and amount Muscular arteries Central BP What creates central BP?
Kozo Hirata, MD; Masanobu Kawakami, MD; Michael F ORourke, MD, DSc*Circ J 2006; 70: 1231–1239 Augmentation Index (AIx) = Augmentation Pressure / Pulse Pressure If reflected wave travels fast and arrives during systole it creates augmentation pressure, extra pressure work for the heart during systole.
A high augmentation index is a deadly backdraft of pressure which exhausts the heart over time.
Run animation Wave reflection animation can be found at: http://atcormedical.com/wave_ref lection.html
Augmentation Index (AIx) High AIx = unnecessary heart work. High AIx leads to LVH and cardiomyopathy. Lower AIx is better. Treatments that lower AIx help the patient.
When is AIx high-- chronically? Normal aging Obesity Atherosclerosis Diabetes Pre-eclampsia Inflammatory arthritis Renal failure
WW Nichols Curr Opin Cardiol 2002, 17:543–551 As healthy individuals age, reflected wave arrives at ascending aorta earlier and increases augmentation index and central pulse pressure. Three members of same family.
Central BPs– ASCOT / CAFE study Lower central BPs are associated with better CV outcomes. Amlodipine achieved lower central BPs and had better CV outcomes than atenolol, despite achieving the same brachial artery BPs. CAFE / ASCOT study, M. ORourke (Circulation. 2006;113:1213-1225.)
Four months Rx with lisinopril decreased central aortic pulse pressure and augmentation index. WW Nichols Curr Opin Cardiol 2002, 17:543–551
6 months Rx with atorvastatin decreased central aortic pulse pressure and augmentation index. WW Nichols Curr Opin Cardiol 2002, 17:543–551
Adams KF, Am J Health-Syst PharmVol 61 May 1, 2004 Suppl 2 ACE inhibitors and aldosterone antagonists reverse LV hypertrophy– via central BP effects?.
ACE inhibitors, statins and aldosterone antagonists can reverse LV hypertrophy is this due to decreased AIx and strain on the heart?
What makes AIx go down-- chronically? Exercise Weight loss Red wine Statins Control of blood pressure (ACEI and CCB) NTG
Ultra-marathon runner, 30 yo, at rest, seated. AIx = -14%. Note high diastolic radial and CBP.
When is AIx high– acutely? Arterial compression in legs (squatting) Cold body temperature. Nicotine ingestion
Tom Archer, 58 y.o., while squatting. AIx = 21%
Tom Archer, seated, very cold from being outside in winter. AIx = 27%
David G. Edwards,1 Amie L. Gauthier,2 Melissa A. Hayman,2 Jesse T. Lang,2 and Robert W. Kenefick2J Appl Physiol 100: 1210– 1214, 2006. Exposure of healthy young adults to cold air for 30 min increases augmentation index.
What makes AIx decrease-- acutely? Exercise Alcohol Lowering blood pressure NTG
Tom Archer, 58 yo, after work, seated comfortably. AIx = 11%.
Tom Archer, 58 yo, after exercise and wine. AIx = 1%
Perioperative hypothermia increases cardiac event rate. Is this due to increased AIx with hypothermia?
Could AIx guide therapies in anesthesia and intensive care? NTG in low doses may work by decreasing wave reflection, CBP and afterload. First trial of AIx guided treatment would seem to be afterload reduction for the depressed LV– as in coming off CPB. SphygmoCor Mx does analysis on arterial line tracing, so it is continuous and hands-free.
Is this an area which deserves more attention in Critical Care Medicine?