Near-Infrared Perfusion During Minimally Invasive Thoracic Surgery

Current Surgical Approaches to Thoracic Malignancies are Imperfect: Thoracic malignancies are among the most deadly cancers diagnosed across the world. Non-small cell lung cancer (NSCLC) remains the number one cause of cancer related mortality in the United States and across the world. Esophageal cancer is the second most common thoracic malignancy, and is the fastest growing malignancy in the United States. Together, these 2 tumor types account for more an annual mortality of 150,000 in the United States alone. For patients with stage I and stage II disease, surgery provides the best opportunity for long-term survivorship for both malignancies; however, operative intervention is associated with significant morbidity and upwards of 20% of patients have complications.

As with surgery involving other body cavities, safe oncologic resection of thoracic tumors involves a careful understanding of the arterial blood flow to tissues that are to be (1) resected and (2) left behind. Despite the importance of these considerations, there remains very few tools to help the surgeon with this assessment. Two examples of these clinical dilemmas involve (1) pulmonary artery delineation during pulmonary segmentectomy and (2) conduit assessment during esophagectomy. Consequences of improper perfusion assessment can involve a variety of complications such as leak, stricture, abscess, or unnecessary resection.

This protocol describes a tool to address these unmet needs. More specificall, this non-significant risk study will assess feasibility of the Olympus VISERA ELITE II Near-infrared (VE2 NIR) Imaging System (Olympus Medical Systems Corp., Tokyo, Japan to intraoperatively assess perfusion during (1) pulmonary segmentectomy and (2) gastric conduit perfusion during esophagectomy by detecting systemically delivered indocyanine green (ICG). The VE2 NIR Imaging system has obtained 510k clearance from the US FDA for blood flow and related tissue perfusion.

Indocyanine Green (ICG): Indocyanine green is a water-soluble, NIR fluorophore with a molecular weight of 774.9 kDA. When intravenously delivered, ICG binds to plasma albumin thus creating a circulating nanoparticle. The main mechanism of excretion is hepatic as the liver excretes more than 80% of the available ICG in less than 24 hours. ICG is the most intensively studied NIR contrast agent and was approved by the United States Food and Drug Administration (FDA) for human administration in 1958. As a fluorophore, ICG has a peak absorption wavelength of 805 nm and a peak emission wavelength of 830 nm. ICG is inexpensive, non-toxic and readily available, making it an ideal contrast agent for intraoperative NIR imaging. The FDA specifically approves ICG for cardiac output, hepatic function and ophthalmic angiography.

Previous clinical data pertaining to ICG-based NIR imaging of gastric conduit perfusion at the time of esophagectomy: Esophagectomy remains a mainstay of multi-modality therapy for esophageal cancer. During esophagectomy, the diseased esophagus is resected and the remaining portion of the stomach (gastric conduit) is brought through the chest where it is anastomosed to either the thoracic or cervical esophagus. Anastomotic and conduit complications significantly contribute to morbidity and mortality associated with esophagectomy. Adequate vascular perfusion of the gastric conduit is vital to avoid these complications. To date, conduit viability is assessed intraoperatively by surgeon observational assessment, which is subjective. Thoracic surgeons are in desperate need of new technologies that can better assess tissue perfusion and ischemia of the gastric conduit. One such technique is the use of intraoperative NIR imaging with ICG to directly assess these parameters.