Significant thrombus in saccular aneurysm in a patient with polycythemia: a case report.

BACKGROUND: Morphologically, the risk of aortic aneurysm rupture is mainly evaluated based on its type (e.g., fusiform or saccular) and diameter. Based on the finite element analysis, peak wall stress has been identified as a more sensitive and specific predictor of rupture in recent years. Moreover, in finite analysis, the neck of aneurysm is the highest peak wall stress and is associated with the rupture point. CASE PRESENTATION: A saccular aortic aneurysm (84 mm) was incidentally detected during preoperative examination for chronic empyema in a 74-year-old male patient with a history of polycythemia. Aortic arch graft replacement using an open stent was performed. CONCLUSIONS: Morphologically, this case was associated with a very high risk of rupture; nevertheless, it did not rupture. In this case, a mural thrombus (likely formed due to polycythemia) covered the neck of aneurysm that is experiencing the highest peak wall stress and is associated with the rupture point. The mural thrombus decreased peak wall stress and could reduce the risk of rupture even for huge saccular aneurysms. Furthermore, the mural thrombus was fully occupied in aneurysms, such as during coil embolization. Thus, polycythemia could decrease the risk of rupture of huge saccular aneurysms.

Decision making of iatrogenic coronary embolism after SAVR: a case report.

BACKGROUND: Acute coronary artery obstruction is a rare but lethal complication of surgical aortic valve replacement (SAVR), which may be caused by embolization of resected native tissue such as calcium plaque, thrombus, or perivalvular aortic tissue like fat embolus. Coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) are the main treatment modalities. PCI is less invasive, but it is difficult to determine its feasibility intraoperatively. CASE PRESENTATION: We report an 86-year-old woman who had asymptomatic severe aortic stenosis. She had scleroderma with an intractable left leg ulcer and bilateral leg varices. Considering the possibility of the spread of infection from the leg wound, SAVR was performed via right anterior thoracotomy to avoid complications such as mediastinitis. Coronary artery occlusion was suspected after weaning of cardiopulmonary bypass in the operation room due to asynergy with ST elevation and new severe mitral regurgitation. Transoesophageal echocardiography (TEE) helped diagnose coronary obstruction by embolus based on the degree of stenosis and the movement of the stenosis site. Percutaneous catheter intervention was performed successfully to restore coronary perfusion. CONCLUSION: TEE facilitated the diagnosis of coronary artery stenosis caused by an embolus and helped in determining the feasibility of percutaneous catheter intervention, thus allowing us to choose PCI over CABG as a less invasive surgery. This is especially invaluable in cases where obtaining a saphenous graft for CABG is difficult or where CABG would have required conversion from minimally invasive surgery (anterolateral approach) to median sternotomy.

Blood flow evaluation of reconstructed gastric tube in esophageal surgery using near-infrared imaging and retrospective time-intensity curve analysis.

PURPOSE: Near-infrared fluorescence imaging using indocyanine green (ICG-NIFI) can visualize a blood flow in reconstructed gastric tube; however, it depends on surgeon's visual assessment. The aim of this study was to re-analyze the ICG-NIFI data by an evaluator independent from the surgeon and feasibility of creating the time-intensity curve (TIC). METHODS: We retrospectively reviewed 97 patients who underwent esophageal surgery with gastric tube reconstruction between January 2017 and November 2022. From the stored ICG videos, fluorescence intensity was examined in the four regions of interest (ROIs), which was set around the planned anastomosis site on the elevated gastric tube. After creation the TICs using the OpenCV library, we measured the intensity starting point and time constant and assessed the correlation between the anastomotic leakage. RESULTS: Postoperative leakage occurred for 12 patients. The leakage group had significantly lack of blood flow continuity between the right and left gastroepiploic arteries (75.0% vs. 22.4%; P < 0.001) and tended to have slower ICG visualization time assessed by the surgeon's eyes (40 vs. 32 s; P = 0.066). TIC could create in 65 cases. Intensity starting point at all ROIs was faster than the surgeon's assessment. The leakage group tended to have slower intensity starting point at ROI 3 compared to those in the non-leakage group (22.5 vs. 19.0 s; P = 0.087). CONCLUSION: A TIC analysis of ICG-NIFI by an independent evaluator was able to quantify the fluorescence intensity changes that the surgeon had visually determined.

Multimodality Diagnosis of Mesenteric Ischemia.

Early diagnosis of mesenteric ischemia remains challenging because mesenteric ischemia presents with no key symptoms or physical findings, and no laboratory data specifically indicates intestinal tissue ischemic status before necrosis develops. While computed tomography is the standard for diagnostic imaging, there are several limitations: (1) repeated assessments are associated with increased radiation exposure and risk of renal damage; (2) the computed tomography findings can be misleading because necrosis occasionally occurs despite opacified mesenteric arteries; and (3) computed tomography is not necessarily available within the golden time of salvaging the intestines for those patients in the operating room or at a place far from the hospital. This article describes a challenge to overcome such limitations using ultrasonography and near-infrared light, including clinical studies. The former is capable of providing not only morphologic and kinetic information of the intestines but also perfusion of the mesenteric vessels in real-time without transferring the patient or exposing them to radiation. Transesophageal echocardiography enables precise assessment of mesenteric perfusion in the OR, ER, or ICU. Representative findings of mesenteric ischemia in seven aortic dissection cases are presented. Near-infrared imaging with indocyanine green helps visualize the perfusion of vessels and intestinal tissues although this application requires laparotomy. Findings in two cases (aortic aneurysm) are shown. Near-infrared spectroscopy demonstrates oxygen debt in the intestinal tissue as digital data and can be a candidate for early detection of mesenteric ischemia without laparotomy. The accuracy of these assessments has been confirmed by intraoperative inspections and postoperative course (prognosis).

The impact of the quantitative assessment procedure for coronary artery bypass graft evaluations using high-resolution near-infrared fluorescence angiography.

PURPOSE: Near-infrared angiography (NIR) is used for on-site graft assessment during coronary artery bypass grafting. This study evaluated the results of a quantitative NIR assessment using a new high-resolution NIR device (h-NIR) for graft assessment. METHODS: Forty-three patients were enrolled in our study. Internal thoracic artery (ITA) grafts anastomosed to the left anterior descending artery and examined intraoperatively using h-NIR were included. The ITA grafts were divided into 2 groups for a comparative analysis: patent grafts (P group; n = 37) and failed grafts (F group; n = 6). The graft flow was evaluated by a "quantitative NIR assessment", and the fluorescence luminance intensity (FLI) was measured. Direct observation of the graft and anastomosis with h-NIR was also performed. RESULTS: The FLI was higher in the P group than in the F group. The receiver operating characteristic analysis revealed the following cut-off values for FLIs depending on imaging duration: 21.1% at 1 s, 35.5% at 2 s, 58.4% at 3 s, and 83.3% at 4 s. The sensitivity and specificity for detecting graft failure were 83.3% and 69.8-80.6%, respectively. Furthermore, h-NIR was also able to visualize arterial dissection in ITA grafts. CONCLUSIONS: A quantitative NIR assessment with an h-NIR device can improve the detectability of anastomotic stenosis, and h-NIR successfully detected arterial dissection of grafts.

Surgical ligation level of the bronchial artery influences tissue oxygen saturation of the bronchus and the incidence of postoperative bronchofistula after pulmonary lobectomy.

BACKGROUND: Lobectomy, or the removal of a lobe of the lung, is the most commonly performed lung cancer surgery. One of the most severe postoperative complications is a bronchial stump fistula, which often occurs following a right lower lobectomy. During lymph node dissection, the bronchial arteries, which supply blood to the bronchus, are cut. Subsequently, reduced blood supply to the bronchus may result in bronchofistula. We investigated the relationship between the level of the surgical ligation of the bronchial arteries and the decrease in blood flow at the bronchial stump during a right lower lobectomy. This study aimed to clarify the relationship between the anatomical amputation level of the bronchial artery and the decrease in tissue oxygen saturation at the bronchial stump, allowing us to identify a surgical procedure that reduces the risk of a bronchopleural fistula following pulmonary lobectomy and an appropriate bronchial artery amputation site that could be used in future lobectomies. METHODS: We developed a new system (micro-tissue oxygen saturation) that enabled the semi-quantification of the oxygen saturation of thin tissues in pinpoint during video-assisted thoracic surgery. Changes in the blood flow at the bronchial stump were examined during lymph node dissection and bronchial artery amputation using a biological pig lobectomy model. RESULTS: The regional oxygen saturation level at the bronchial wall was 95.5%±1.0% in normal conditions. A gradual decrease in regional oxygen saturation was observed, as the cutting point of the bronchial artery was moved higher. When the bronchial artery coursing into the middle lobe bronchus was preserved, the blood flow in the bronchus was preserved at 82.8%±1.3%. When the branches of the bronchial arteries running both inside and outside of the intermediate bronchial trunk were cut at high positions, regional oxygen saturation level decreased to 55.7%±1.2%. CONCLUSIONS: The preservation of at least one bronchial artery at the level of the middle lobe bronchus minimizes the reduction of tissue oxygen saturation at the lower lobe bronchial stump. The ligation of bronchial arteries at a higher position results in desaturation <60%, which may increase the risk of bronchial stump fistula.

Investigation of air bubble properties: Relevance to prevention of coronary air embolism during cardiac surgery.

Although de-airing procedures are commonly performed during cardiac surgery, use of these procedures is not necessarily based on evidence. Uncertainly remains around the size of bubbles that can be detected by echocardiography, whether embolized air or carbon dioxide can be absorbed, and the reasons for embolic events occurring despite extensive de-airing. Since air bubbles are invisible in the blood, we used simple experimental models employing water and 10% dextran solution to determine the correlation between actual bubble size and the depicted size on echocardiography, bubble size, and floatation velocity and the absorption of carbon dioxide under embolization and irrigation conditions. Bubbles depicted as larger than 1 mm were overestimated by echocardiography: the actual size was larger than 0.4 mm in diameter. While bubbles of 0.5 mm had a floatation velocity of 2 to 3 cm/s, the buoyancy of bubbles smaller than 0.3 mm was negligible. Thus, bubbles that are depicted as larger than 1 mm on echocardiography or that present with apparent buoyancy should be visible and need to be meticulously removed. However, echocardiography cannot distinguish bubbles of around 0.1 mm in diameter from those of capillary size (<10 µm). Thus, we advise continuous venting of dense bubbles until they become sparse. While carbon dioxide was rapidly absorbed when circulating, the absorption of embolized carbon dioxide was negligible. These results suggest that detected intracardiac air represents residual "air," with carbon dioxide already absorbed. Therefore, the use of conventional de-airing procedures needs reconsideration: air and buoyant bubbles should be removed from the heart before they are expelled into the aorta; this requires timely and precise assessment with transesophageal echocardiography and effective collaboration between surgeons, anesthesiologists, and perfusionists.

Fluorescence visualization of the intersegmental plane by bronchoscopic instillation of indocyanine green into the targeted segmental bronchus: determination of the optimal settings.

OBJECTIVE: To determine the appropriate amount of indocyanine green for bronchial insufflation. METHODS: We enrolled 20 consecutive patients scheduled for anatomical segmentectomy in the Kochi Medical School Hospital. After inducing general anesthesia, 6 to 60 mL of 200-fold-diluted indocyanine green (0.0125 mg/mL) was insufflated into the subsegmental bronchi in the targeted pulmonary segmental bronchus. The volume of the targeted pulmonary segments was calculated using preoperative computed tomography. Fluorescence spread in the segmental alveoli was visualized using a dedicated near-infrared thoracoscope. RESULTS: The targeted segment was uniformly visualized by indocyanine green fluorescence in 16/20 (80.0%) cases after insufflating indocyanine green. A receiver operating characteristic curve indicated that the area under the curve was 0.984; the optimal cut-off volume of diluted indocyanine green for insufflation was 8.91% of the calculated targeted pulmonary segment volume. CONCLUSIONS: The setting for indocyanine green insufflation was optimized for near-infrared fluorescence image-guided anatomical segmentectomy. By injecting the correct amount of indocyanine green, fluorescence-guided anatomical segmentation may be performed more appropriately.

The accuracy of cone-beam computed tomography and augmented fluoroscopy-guided bronchoscopic marking of multiple small-sized pulmonary nodules in a hybrid operating room: a retrospective cohort study.

BACKGROUND: For the minimally invasive excision of small-sized pulmonary nodules, bronchoscopic markings are increasingly being performed owing to advancements in video-assisted thoracic surgery (VATS). Hybrid operating room equipment is utilized for bronchoscopic VATS markings. We aimed to compare the marking accuracy between bronchoscopic VATS and other marking techniques such as computed tomography-guided percutaneous marking and conventional X-ray fluoroscopy-guided bronchoscopic marking. METHODS: Patients with small-sized pulmonary nodules scheduled to undergo VATS were enrolled in the study. A mixture of 50 to 100 µL of diluted indocyanine green and iopamidol was injected adjacent to the pulmonary nodules as a VATS marker. Patients receiving each of the three image-guided techniques were categorized into group A (computed tomography-guided percutaneous injection), group B (X-ray fluoroscopy-guided virtual bronchoscopy-assisted bronchoscope injection), and group C (cone-beam computed tomography and augmented fluoroscopy-guided virtual bronchoscope-assisted bronchoscopic injection in the hybrid operating room). VATS marking accuracy and procedural complications were compared among the three groups. RESULTS: In total, 61 patients with 73 pulmonary nodules were eligible for analysis. VATS marking was successful for 15/16 nodules in group A, 28/30 nodules in group B, and 25/27 nodules in group C. Marking accuracy was 5.75±4.59, 15.00±14.02, and 6.05±6.11 (mm), respectively. Multiple markings were successful in 0/1 (0%), 5/6 (83.3%), and 5/5 (100.0%) nodules in groups A, B, and C, respectively. A small pneumothorax occurred in 3/15 (20.0%) patients in group A. CONCLUSIONS: The cone-beam computed tomography and augmented fluoroscopy-guided bronchoscopic approach performed in a hybrid operating room is accurate and equivalent to the computed tomography-guided percutaneous approach, and it enables the VATS marking of multiple pulmonary nodules without causing a secondary pneumothorax.

Near-infrared spectroscopy for monitoring free jejunal flap.

BACKGROUND: Although the free jejunal graft is commonly used for reconstruction after resection of a tumor of the pharynx or cervical esophagus, adequate monitoring for detecting graft failure is not available. We employed near-infrared spectroscopy to measure regional oxygen saturation (rSO2) in the graft. METHODS: In 25 consecutive cases who underwent reconstructive surgery using a free jejunal graft, the feasibility of postoperative rSO2 monitoring was examined along with the changes in rSO2 values following vascular clamping or reperfusion. RESULTS: No operative mortality occurred, and except for one case of subcutaneous hematoma that necessitated evacuation surgery, no complications related to surgery or graft failure occurred. Postoperative rSO2 monitoring was feasible for >50 hours in most cases. It mostly remained >55% with a stable hemoglobin index (HbI) which reflects tissue hemoglobin density. A marked increase in the HbI was noted in a patient with hematoma. Intraoperatively, the rSO2 of intact jejunal tissue was >60% in every case but dropped within a few minutes after arterial clamping because of decreased oxygenated hemoglobin concentration. With venous clamping, the HbI was elevated while the rSO2 remained unchanged or was slightly decreased. Upon graft reperfusion, the rSO2 rapidly recovered in all 18 cases because of the recovery of oxygenated hemoglobin concentrations. CONCLUSIONS: The near-infrared spectroscopic assessment sensitively and accurately reflected the condition of the jejunal graft. It appears to be a promising postoperative method for monitoring graft perfusion. An rSO2 value of 55% appears to be an adequate criterion for ischemia.

Preoperative AminoIndex Cancer Screening (AICS) abnormalities predict postoperative recurrence in patients undergoing curative resection for non-small cell lung cancer.

BACKGROUND: AminoIndex™ Cancer Screening (AICS (lung)) was developed as a screening test for lung cancer using a multivariate analysis of plasma-free amino acid (PFAA) profiles. According to the developed index composed of PFAA, the probability of lung cancer was categorized into AICS (lung) ranks A, B, and C in order of increasing risk. The aim of the present study was to investigate the relationship between the preoperative AICS (lung) rank and surgical outcomes in patients who underwent curative resection for non-small cell lung cancer (NSCLC). METHODS: Preoperative blood samples were collected from 297 patients who underwent curative resection for NSCLC between 2006 and 2015. PFAA concentrations were measured. The relationship between the preoperative AICS (lung) rank and clinicopathological factors was examined. The effects of the preoperative AICS (lung) rank on postoperative outcomes were also analyzed. RESULTS: The AICS (lung) rank was A in 93 patients (31.3%), B in 82 (27.6%), and C in 122 (41.1%). The AICS (lung) rank did not correlate with any clinicopathological factors, except for age. Based on follow-up data (median follow-up period of 6 years), postoperative recurrence was observed in 22 rank A patients (23.7%), 15 rank B (18.3%) and 49 rank C (40.2%). In the univariate analysis, preoperative AICS (lung) rank C was a worse factor of recurrence-free survival (p = 0.0002). The multivariate analysis identified preoperative AICS (lung) rank C (HR: 2.17, p = 0.0005) as a significant predictor of postoperative recurrence, particularly in patients with early-stage disease or adenocarcinoma. CONCLUSION: Preoperative AICS (lung) rank C is a high-risk predictor of postoperative recurrence in patients undergoing curative resection for NSCLC.

Preoperative Clinical Features and High Pulmonary Wedge Pressure with a Discordant Pattern as Prognostic Factor in Hemodialysis Patients with Severe Aortic Valve Stenosis.

Hemodialysis (HD) is one of the important risks for the development of cardiovascular disease, including aortic valve stenosis (AS). Although aortic valve replacement (AVR) is a beneficial treatment for AS, HD patients are known to show a high rate of mortality after AVR than non-HD patients.We retrospectively studied 109 patients who underwent AVR for severe AS, 18 of which were HD patients. Survival rate after AVR, preoperative clinical data, and surgical procedure were investigated.In preoperative clinical features, left ventricular end-diastolic diameter was larger, intraventricular septum thickness (IVST) was thicker, left ventricular mass index (LVMI) was higher, left ventricular ejection fraction was lower, E/e' was higher, and pulmonary arterial wedge pressure (PAWP) was higher in the HD group than in the non-HD group. During a follow-up period of 3.2 ± 2.3 years after AVR, patients receiving HD had a worse prognosis than those without HD treatment: the 3-year survival rate after surgery in the HD group was 36.2% and that in the non-HD group was 84.9%. With regard to prognostic factors in the whole cohort, significant differences were found in IVST, LVMI, E/e', PAWP, and HD. In patients receiving HD, abnormally high PAWP for their right atrial pressure (RAP) was observed, suggesting that PAWP and RAP were discordant, and univariate analysis revealed that high PAWP was the only predictor of mortality in HD patients after surgery.Preoperative PAWP with a discordant pattern in HD patients might be an important prognostic predictor after AVR.

Near-infrared fluorescent solid material for visualizing indwelling devices implanted for medical use.

BACKGROUND: In clinical practice, various devices are implanted into the body for medical reasons. As X-ray fluoroscopy is necessary to visualize medical devices implanted into the body, the development of a less-invasive visualization method is highly desired. This study aimed to investigate the clinical applicability of our novel solid material that emits near-infrared fluorescence. METHODS: We developed a solid resin material that emits near-infrared fluorescence. This material incorporates a near-infrared fluorescent pigment, with quantum yield ≥ 20 times than that of indocyanine green. It can be sterilized for medical treatment. This resin material is designed to be molded into a catheter and inserted into the body with an endoscope clip. In this preclinical experiment using a swine model, the resin material was embedded into the body of the swine and visualized with a near-infrared fluorescence camera system. RESULTS: Endoscopic clips were placed in the mucosa of the stomach, esophagus, and large intestine, and the indwelling ureteral catheters were successfully visualized by near-infrared fluorescence laparoscopy. CONCLUSIONS: We confirmed the tissue permeability of the fluorescence emitted by our novel near-infrared fluorescent material and the possibility of its clinical application. This material may allow visualization of devices embedded in the body.

Feasibility, efficacy, and safety of cell-free and concentrated ascites reinfusion therapy (KM-CART) for malignant ascites.

Efficacy for alleviating signs/symptoms of malignant ascites of a renovated CART (cell-free and concentrated ascites reinfusion therapy) system, called KM-CART, was evaluated. A total of 4781 KM-CART procedures were performed in 2109 patients. All patients were accepted unless hemodynamically unstable or consciousness impaired. The ascites were processed and drip-infused into the patient. There were no major complications or deaths. The mean drainage volume was 6.2 L (maximum: 27.7 L), patient symptoms (numerical scale system) were significantly alleviated (45.1 ± 19.0 reduced to 21.2 ± 14.2, P < .001), and patient leg circumference significantly decreased (33.3 ± 4.4 cm reduced to 30.5 ± 4.4 cm, P < .001) without exacerbation of renal function. Collected cancer cells could be utilized for immune therapy. KM-CART is capable of improving the "quality of best supportive care" and can be beneficial in conjunction with medication for alleviating malignant pain.

Transesophageal Echocardiography During Cardiopulmonary Resuscitation (CPR-TEE).

BACKGROUND: To take full advantage of transesophageal echocardiography (TEE) during cardiopulmonary resuscitation (CPR), we propose a flowchart derived from representative cases.Methods and Results:TEE was used in patients requiring CPR to obtain information potentially helpful for rescue. TEE navigated the CPR procedures (navigation TEE), identified the possible cause of arrest (focus TEE), and optimized treatment while checking for pitfalls (secure TEE). In addition, TEE corrected prehospital misdiagnoses and detected new complications caused by CPR. CONCLUSIONS: TEE provides valuable information without interrupting CPR procedures. It is hoped that our flowchart may facilitate goal-directed, efficient assessment.

Intraoperative Transesophageal Echocardiography for Coronary Artery Assessment.

Background: In surgical aortic valve replacement (SAVR), coronary arteries are routinely assessed by transesophageal echocardiography (TEE) to prevent undesirable complications. This study evaluated the capabilities and pitfalls of TEE assessment. Methods and Results: Of 147 consecutive SAVR patients undergoing aortic stenosis, the TEE records for 130 patients, in which the procedures were conducted by a single examiner, were analyzed retrospectively regarding data acquisition and the accuracy of detecting an anomalous origin, high or low takeoff, ostial diameter, and short left main truncus (LMT). The left and right coronary arteries could be visualized in every patient. A left coronary ostium >5 mm was found in 33 patients (25.4%). TEE revealed an anomalous origin in 2 patients (1.5%) that had not been diagnosed, but missed it in another patient. High takeoff was noted in 11 patients (8.3%), often associated with aortic disease necessitating aortic repair. In one such patient, occlusion of the right coronary artery was detected, necessitating coronary revascularization. Short LMT was found in 15 patients (11.8%) but misdiagnosed due to artifact in 1. During selective cardioplegia, malperfusion of the left anterior descending artery due to deep cannula placement was detected. Conclusions: TEE provides fairly accurate assessment in SAVR, including detection of undiagnosed pathologies or pitfalls related to coronary arteries, although misdiagnosis due to artifacts should be kept in mind.

Myocardial infarction-related left ventricular rupture with the tear across the ventricular wall detected on echocardiography.

A 79-year-old man underwent repair surgery for a left ventricular free wall rupture after an acute myocardial infarction. The surgical procedure followed for ventricular rupture was according to the rupture type. The patient showed slowly oozing bleeding through small holes. Epicardial echocardiography detected the color signals that crossed the left ventricular wall. Two channels were directly connected from the ventricular cavity to the epicardial hole. Although the bleeding hole was covered with collagen hemostats using a sutureless technique, the bleeding remained, probably because of the pressure exerted by the left ventricle on the channels connected to the epicardial hole. The suture closure technique might be better in cases with channels across the ventricular wall, as detected on echocardiography. We describe a case of left ventricular rupture followed by acute myocardial infarction in which the channel connected to the ruptured ventricular tear was detected on epicardial echocardiography.

Influence of residual coronary flow on bypass graft flow for graft assessment using near-infrared fluorescence angiography.

PURPOSE: Near-infrared fluorescence angiography (NIR) detects the attenuation of fluorescence luminance intensity (FLI) through coronary artery bypass grafts affected by anastomotic stenosis. This study investigates the influence of residual blood flow of the host coronary artery (Ho) on bypass graft (Gr) FLI using a coronary artery bypass (CABG) model. METHODS: A mock circuit system was created using artificial vessels and artificial blood was supplied to the Gr and the Ho. We used NIR to examine the changes in FLI through the Gr. RESULTS: The Gr FLI was significantly attenuated according to the degree of Gr stenosis. The Gr FLI did not differ significantly among all degrees of Ho stenosis. High FLI grafts included grafts with degrees of Gr stenosis ≤ 75%, regardless of the severity of Ho stenosis. Moderate and low FLI grafts had 90 or 99% Gr stenosis, regardless of the severity of Ho stenosis. Gr FLI with 99% Gr stenosis was higher in 99% Ho stenosis than in ≤ 90% Ho stenosis. CONCLUSIONS: A high Gr FLI indicated the absence of ≥ 90% stenosis in the anastomosis and a low Gr FLI indicated severe stenosis in the anastomosis despite Ho stenosis. High Ho stenosis may prevent the attenuation of Gr FLI in severely stenosed grafts.