spatial frequency domain imaging: it is time to evolve from ......spatial frequency domain imaging:...
TRANSCRIPT
Spatial Frequency Domain Imaging: It is Time to Evolve From the ABI
Jeffrey D. Lehrman, DPM, FASPS, MAPWCA, CPC
Advisor, APMA Coding Committee
Expert Panelist, Codingline
Advisor, APMA MACRA Task Force
Fellow, American Academy of Podiatric Practice Management
Board of Directors, American Society of Podiatric Surgeons
Board of Directors, American Professional Wound Care Association
Editorial Advisory Board, WOUNDS
Twitter: @DrLehrman
Neuropathic Ulcer 5-Year Mortality Rate
3
References: 1. Papanas N, et al. Drug Saf. 2010;33:455-461.
49% of ulcers may fail to heal despite traditional good ulcer care 1
Quality 45%
ACI 25%
Clinical Practice Improvement Activities 15%
Cost 15%
MIPS Score Performance Year 2019
Calculated by:
Medicare Spending per Beneficiary (MSPB)
& Total Per Capita Cost Measures
Cost Category
MSPB
• Sum of standardized, risk-adjusted spending across all eligible episodes divided by number of episodes
• Episode = All Medicare claims between 3 days prior to a hospital admission (“index admission”) and 30 days after hospital discharge.
Total Per Capita Cost
• Total Cost per Beneficiary • Payment standardized • Annualized • Risk adjusted • Specialty adjusted
Source: Agency for Healthcare Research and Quality (AHRQ), Center for Delivery, Organization, and Markets, Healthcare Cost and Utilization Project (HCUP) National Inpatient Sample
(NIS), 2014
Overview of Operating Room Procedures During Inpatient Stays in U.S. Hospitals, 2014 Kimberly W. McDermott, Ph.D., William J. Freeman, M.P.H., and Anne Elixhauser, Ph.D. H-CUP Statistical Brief #233
Inpatient Stay With OR Procedure
Inpatient Stay Without OR Procedure
2 X >>>>>
$$
Overview of Operating Room Procedures During Inpatient Stays in U.S. Hospitals, 2014 Kimberly W. McDermott, Ph.D., William J. Freeman, M.P.H., and Anne Elixhauser, Ph.D. H-CUP Statistical Brief #233
Overview of Operating Room Procedures During Inpatient Stays in U.S. Hospitals, 2014 Kimberly W. McDermott, Ph.D., William J. Freeman, M.P.H., and Anne Elixhauser, Ph.D. H-CUP Statistical Brief #233
What Do We Have Now?
• Physical exam • Hand-held doppler • ABI • TBI • TcO2
Reliability of Current Assessment Methods
• Physical exam • Visual: dry, shiny, taut skin, loss of hair on extremity, nails thickened, edema • Dorsalis pedis: Missing in 10% of normal, calcification • Posterior tibial artery pulse: Requires gentle technique to assess • Capillary refill: Normal refill doesn’t “rule out PAD” • Temperature: Normal temperature doesn’t “rule out PAD”
Per American Heart Association Physical examination is imperfect in diagnosing PAD
Collins TC1, Suarez-Almazor M, Peterson NJ
Reliability of Current Assessment Methods • Hand held laser doppler
• Artificially elevated in diabetes, chronic renal disease, and advanced age • Does not offer detailed description of length, severity or type of diseased
vessel • Time and labor consuming
Reliability of Current Assessment Methods
• ABI • Time consuming: Requires patient rest 15 minutes in supine position • Indirect examination that infers anatomical location of occlusion or stenosis • Relatively low specificity: 45% • False negatives
• Arterial calcinosis in diabetes and renal disease (5 – 15% error) • Subclavian or other UE stenosis
• Lack of standardization • Patient and cuff positioning
Reliability of Current Assessment Methods
• TBI • Room must be warm to avoid vasoconstriction • Digital vessels must be present • Non compressible vessels
Reliability of Current Assessment Methods
• Transcutaneous Oximetry • Has been used to predict healing of wounds, responsiveness to hyperbaric
therapy and amputation level • Time consuming
• Long time required for equilibration • On avg. 25 minutes per site studied • Skin thickening and edema • Pharmacologic agents • Decreased baseline levels with age • Significant overlap with normal • Focal measurements
Diagnostic Options
Region Modality Description Measurement Tissue Assessment
(Integrity)
Type Area Oxygenation
Perfusion
Macrovascular
Physical exam Visual, temperature, pulse, & capillary refill Qualitative Local No No
ABI Blood pressure index Quantitative Leg/foot No No
TBI Blood pressure index Quantitative Toe No No
Microvascular TcPO2 Transcutaneous O2 Quantitative Focal Indirect No
SFDI Oxygenation and perfusion Quantitative Plantar surface
(300 x 225mm) Yes Yes
Spatial Frequency Domain Imaging (SFDI)
• Quantifies concentration and oxygenation of hemoglobin in the papillary and reticular dermis
• Generates anatomically relevant oxygenation and perfusion maps
Spatial Frequency Domain Imaging • 5 Biomarker measurements to characterize distribution, perfusion, and
oxygenation -ctHbO2 – Tissue oxyhemoglobin -ctHbR – Tissue deoxyhemoglobin -ctHb1 – Papillary dermis hemoglobin -ctHb2 – Reticular dermis hemoglobin -StO2 – Tissue hemoglobin oxygen saturation
SFDI – Distribution, Perfusion, and Oxygenation 1. Multiple wavelengths of light
- Visible and near-infrared light interrogate subsurface tissue - Ability to measure transcutaneous Hb in superficial and
deeper skin layers (1–3mm)
2. SFDI / Structured Illumination - Patented and proprietary SFDI algorithms measure
transcutaneous Hb signals in skin - Accurate measurement of tissue hemoglobin and
hemoglobin oxygen saturation 3. Quantitative algorithms
- Visualize and quantify changes in distribution, perfusion, and oxygenation of Hb
With Structured Illumination
Without Structured Illumination
Visible Light Near Infrared Light
Arterio-venous shunting in diabetes
• Vasomotor neuropathy causes issues in the periphery vascular beds
• Loss of sympathetic tone in the vessels
• End result is that the tissue is not getting oxygen due to poor extraction
Arterio-venous shunting
1. SFDI Hb ratio identifies PVD in subjects with diabetes • HbT2/HbT1 ratio higher for clinically-validated PVD • ABI correlation to PVD was poor in diabetes subjects • SFDI correlates with TBI in subjects with diabetes
2. Demonstrated non-invasive measurement of circulatory shunting due to diabetes • Measured elevated StO2 and decrease in HbT1 due to diabetes-related arterio-venous
shunting • Conditions result in under-extraction of oxygen and identifies ulceration risk that ABI cannot
identify
Non-invasive measurement of circulatory shunting identifies DFU risk in diabetes where ABI does not
April Color Image ctHb1 ctHb2
StO2
April Report
ctHbO2 ctHbR
SFDI
30
47 68 25
200 40 60
20 9 2
120 37 32
90 84 98
Local change in ctHb. Pre Ulcer?
April SFDI Map Overlay
Technician generates a report with transcutaneous hemoglobin characterization in multiple areas and
can identify high risk areas
April Report
ctHb1 ctHb2
StO2 ctHbO2 ctHbR
47 68 25
200 40 60
20 9 2
120 37 32
90 84 98
31
June follow-up revealed skin breakdown & ulcer formation
June Report
ctHb1 ctHb2
StO2 ctHbO2 ctHbR
June Color Image
32
47 68 25
200 40 60
20 9 2
120 37 32
90 84 98
Spatial Frequency Domain Imaging: It is Time to Evolve From the ABI
Jeffrey D. Lehrman, DPM, FASPS, MAPWCA, CPC
Advisor, APMA Coding Committee
Expert Panelist, Codingline
Advisor, APMA MACRA Task Force
Fellow, American Academy of Podiatric Practice Management
Board of Directors, American Society of Podiatric Surgeons
Board of Directors, American Professional Wound Care Association
Editorial Advisory Board, WOUNDS
Twitter: @DrLehrman