Nearly 150,000 patients in the US undergo lower extremity amputations annually secondary to peripheral arterial disease (PAD) complicated by critical limb ischemia (CLI).1,2,3 To increase a patient?s post-operative quality of life, surgeons attempt to salvage as much limb tissue as possible while also considering the likelihood of primary wound healing at a given level of amputation (LOA).4 The principal challenge in this decision is that surgeons overestimate the likelihood of healing at the selected LOA. Therefore, in the first year, 10% to 35% of amputations eventually require re-amputation to a more proximal level.5-7 This additional treatment prolongs the patient?s return to walking, worsening their condition and deteriorating their mental health. The burden to the healthcare system is immense. The average cost for each amputation is over $70,000, as evidenced by a recent publication that shows diabetic foot ulcer complications, mainly attributed to amputation, cost more than the five most costly forms of cancer.8 Despite these facts, there are no objective studies for selection of LOA in patients with PAD. To address this critical problem, Spectral MD (SMD) has developed a point-of-care imaging device (DeepView), which simultaneously performs multispectral imaging (MSI) and Photoplethysmography (PPG) imaging across the visible and infrared spectrum to obtain a quantitative microvascular tissue assessment. These optical measurements are integrated using artificial intelligence (AI) algorithms to provide a quantitative aid to the physician?s determination of tissue viability at a proposed amputation site. If used for routine assessment prior to amputation, SMD expects DeepView to reduce the rate of re- amputation by 70%, resulting in up to 38,000 fewer re-amputations per year while improving quality of life for amputees and reducing associated health costs. The central objective for SMD?s Phase I SBIR is to perform a feasibility clinical study to demonstrate the DeepView device will achieve greater than 90% accuracy in identifying the healing potential of tissue at the amputation site. This hypothesis will be tested by the following specific aims:
Aim 1 : Complete a Feasibility Study creating a database of pre-amputation images. This data will be used for construction of the AI algorithm to predict amputation site healing potential.
Aim 2 : Identify MSI and PPG features that can accurately predict amputation site healing potential.
Aim 3 :
Using Aim I clinical data, finalize the AI algorithm architecture and estimate sample size needed for a Phase II Pivotal Study in which the necessary training data to achieve at least 90% sensitivity and 90% specificity will be obtained. As of this Supplement request, SMD has initiated a clinical study for feasibility and enrolled the first subject. Through collaboration with the clinical study site Principal Investigator (PI), Dr. Dennis Gable, SMD developed the protocol and trained his research staff at the study site, Baylor Medical Center Plano, in the use of the DeepView device. SMD anticipates enrollment of five subjects each month over the next 6 months. The I-Corps team will consist of the following members: Michael DiMaio, MD ? Role: C-Level Corporate Officer. Dr. DiMaio, MD is Founder and Chief Executive Officer of SMD and has led SMD in obtaining over $30M in non-dilutive government funding and private investments. His distinguished career includes extensive experience as an entrepreneur, clinician, and scientist. With over 20 years? experience as a cardiovascular surgeon, Dr. DiMaio has a widespread network of physicians and hospitals from which to draw contacts for customer interviews. Jeffrey Thatcher, PhD ? Role: PI. Dr. Thatcher is the Chief Scientist at SMD and is a leader in the development of diagnostic imaging for soft tissue diseases. He led SMD in conceptualizing and inventing SMD?s core imaging technology undergoing clinical trials in three wound diagnostics applications including: burns; diabetic ulcers; and amputation. Wensheng Fan, MS ? Role: Industry Expert. Wensheng Fan is Executive Vice President and Chief Technology Officer at SMD. He is an executive, entrepreneur, and innovator with over 20 years of experience in natural speech recognition and real time imaging systems. At SMD, he leads market engagement, strategic financial planning, and device development.
In patients with peripheral arterial disease, reported rates of re-amputation due to non-healing of a primary amputation are very significant?approximately 20% of below-the-knee amputations require eventual revision, with even higher rates established for amputations at the level of the foot. There are no gold-standard tests for selection of level of amputation (LOA) to aid clinical judgment. To address this critical problem, SpectralMD is developing the DeepView-Gen2 imaging device that integrates multispectral imaging and a machine learning algorithm to quantitatively measure microvascular blood flow and tissue healing potential to assist in the clinical selection of LOA and minimize the incidence of re-amputation and its associated morbidity and mortality.
