Intraoperative Flow Research Articles

Advances in Intraoperative Flow Cytometry.

Flow cytometry is the gold-standard laser-based technique to measure and analyze fluorescence levels of immunostaining and DNA content in individual cells. It provides a valuable tool to assess cells in the G0/G1, S, and G2/M phases, and those with polyploidy, which holds prognostic significance. Frozen section analysis is the standard intraoperative assessment for tumor margin evaluation and tumor resection. Here, we present flow cytometry as a promising technique for intraoperative tumor analysis in different pathologies, including brain tumors, leptomeningeal dissemination, breast cancer, head and neck cancer, pancreatic tumor, and hepatic cancer. Flow cytometry is a valuable tool that can provide substantial information on tumor analysis and, consequently, maximize cancer treatment and expedite patients' survival.

Intraoperative Flow Cytometry for the Characterization of Gynecological Malignancies.

Simple SummaryAneuploidy and high proliferative potential are distinct features of neoplastic cells. Based on the established role of intraoperative flow cytometry in various types of cancer, the aim of the present study was to investigate its role in cancer cell identification during surgery for gynecological malignancies. The analysis time was 5–6 min per sample. A large percentage of tumors were characterized as aneuploid, while all tumor samples had a significantly high proliferation. Flow cytometry was performed in accordance with pathological evaluation, and the method had high sensitivity and specificity. Our results verify the value of intraoperative flow cytometry in gynecological malignancies, and warrant further investigation in multicenter studies.Cell-cycle analysis has shown the presence of aneuploidy to be associated with poor prognosis. We developed an innovative rapid cell-cycle analysis protocol (the Ioannina protocol) that permitted the intraoperative identification of neoplastic cells in a plethora of malignancies. Herein, we aimed to investigate the potential role of cell-cycle analysis in the intraoperative characterization of gynecological malignancies. Women who underwent surgery for gynecological malignancies in our institution over a three-year period were included in this study. Permanent section pathology evaluation was used as the gold standard for malignancy evaluation. Total accordance was observed between flow cytometry and pathology evaluation. In total, 21 aneuploid cancers were detected following DNA index calculation. Of these, 20 were hyperploid and 1 was hypoploid. In addition, tumor samples were characterized by a significantly lower percentage of cells in G0/G1, as well as an induced tumor index. The response time for flow cytometry to obtain results was 5–6 min per sample. It seems that flow cytometry analyses for intraoperative tumor evaluation can be safely expanded to gynecological malignancies. This is a novel practical approach that has been proven valuable in several tumor types to date, and also seems to be reliable for gynecological malignancies. Intraoperative flow cytometry is expected to be crucial in decisions of lymph node dissection in endometrial cancers, due to its rapid response regarding the tumor invasion of part or all of the myometrial thickness. In this way, the surgeon can quickly modify the plane of dissection. Our results warrant the further investigation of applying iFC in larger, multicenter studies.

Intraoperative Flow Measurement as a Quality Control during Carotid Endarterectomy in a Teaching Hospital Setting

Background: To evaluate the technical results of an arterial repair, a variety of intraoperative imaging and assessment techniques can be used during carotid endarterectomy (CEA). The aim of the study was to evaluate the usefulness of intraoperative ultrasound flow measurement as a quality control after primary CEA in a teaching hospital setting. Methods: Over 36 months, 107 consecutive CEAs were performed at our institution. Retrospectively acquired demographics, intraoperative flow measurements, duplex results, revisions, and surgical outcomes were reviewed. Postoperative 30-day transient ischemic attack (TIA), stroke, and death rates were analyzed. Results were compared with ultrasound flow measurement and duplex ultrasonography. Results: From March 2012 to March 2015, 107 primary consecutive CEAs were performed in 107 patients (71% male, 29% female), whose age ranged from 51 to 81 years with a mean age of 68 ± 4 years. Associated risk factors included diabetes for 89 (83%), smoking for 92 (86%), hypertension for 94 (87.8%), chronic renal insufficiency for 71 (66%), and coronary artery disease for 57 (53%) of the patients. Early postoperative duplex scans in all 107 patients showed no significant changes from intraoperative findings. The ipsilateral stroke and death rate in this study was 0 (0/107) and the 30-day death and stroke rate was also 0 (0/107), with no significant difference between trainees and senior surgeons. Three patients (2.8%) had flow < 100 mL/Min and two of them were revised after completion of contrast angiography. Conclusions: The findings of this study indicate that the intraoperative flow measurement is an alternative method for detecting technical errors and a tool for quality-control imaging. Especially for trainees, it makes sense to ensure effectiveness of the procedure upon its completion and to assess the technical adequacy of CEA.

Treatment of Merkel Cell Carcinoma Using Intraoperative Flow Cytometry (iFC) Protocol, Optimized for Head and Neck Lesions, as a Means for Tumor Margin Evaluation - a Case Presentation.

Background: We present the case of a patient with a Merkel cell carcinoma (MCC) of the left preauricular area. Case presentation:A 84-year-old Greek man was examined at the outpatient ENT Department of our clinic with a lesion in the preauricular area that had appeared four months ago. The patient history included antihypertensive and antihyperlipidemic therapy as well as treatment for dementia. The excision of the skin lesion was performed under local anesthesia. The histological examination revealed a Merkel cell carcinoma. The patient underwent a computed tomography (CT) scan that showed a lesion with clear limits in the left parotid gland and lymph nodes. Under general anesthesia, he underwent a left superficial parotidectomy, left submandibular gland excision and radical neck dissection. Histological preparations were analyzed using an intraoperative flow cytometry (iFC) protocol. A radiation therapy concluded the patient's treatment. Conclusion:Even if MCC appears as a less common and more aggressive skin cancer type, a clinician always has to include it in the differential diagnosis of a skin lesion. We found the use of iFC very useful for the diagnosis of this skin cancer.

Detection of cancer cells and tumor margins during colorectal cancer surgery by intraoperative flow cytometry

BackgroundFlow Cytometry is an analytical technique for the precise quantification of cellular phenotype. Intraoperative Flow Cytometry (iFC) utilizes flow cytometry for DNA content/ploidy and cell cycle distribution analysis during surgery for cancer cell characterization and evaluation of tumor margins. Various types of cancers, including intracranial, head and neck, breast and liver malignancies have been evaluated with iFC. In the current study we present an intraoperative Flow Cytometry protocol for colorectal cancer cell detection and potential resection margin evaluation. Materials and methodsThis study includes 106 colorectal cancer patients in which samples from cancer and normal colon epithelium were prospectively collected intraoperatively and comparatively assessed with iFC. Patients' demographics, tumor data and cytometry parameters were assessed. ResultsWe have demonstrated that a cut-off value of 10.5% for tumor-index (fraction of cells in S and G2/M cell cycle phases) predicts with ∼91% accuracy (82.2% sensitivity and 99.9% specificity) the presence of cancer cells. Evaluation of tumor margins by iFC in the subpopulation of rectal cancer patients with or without neoadjuvant therapy, revealed an accuracy of 79% and 88%, respectively. ConclusionOur data support that regarding colorectal cancer, iFC is a useful adjunct method for tumor cell identification and probably margin evaluation, which could be utilized in rectal cancer treatment in the era of organ sparing procedures.

Prediction of postprocedural filter debris after transcarotid revascularization.

Transcarotid revascularization (TCAR) is a technique in which cerebral flow reversal is utilized as embolic protection during carotid stenting. The presence, or absence, of filter debris created during TCAR could potentially be a surrogate to characterize carotid lesions at high risk for embolization and, therefore, explored in this investigation. A retrospective review of TCARs performed within the Indiana University and Memorial Hermann (McGovern Medical School at UTHealth) Health Systems to capture demographics and preoperative variables. A mixed effect multivariate logistic regression model was created to discern the best predictors of intraoperative filter debris. During the study period, from December 2015 to December 2021, we captured filter debris status in 693 of 750 patients containing 323 cases of filter embolization at case completion. With respect to demographics and indications, we found a higher incidence of neck radiation (2.7 vs. 7.1%, p = 0.01) and a more pronounced Charlson Comorbidity Index (CCI; 5.3 ± 0.3 vs 5.7 ± 0.3, p < 0.01) in the filter debris cohort while contralateral carotid occlusion (6.6 vs. 2.9%, p = 0.05) and clopidogrel usage (87.3 vs. 80.1%, p = 0.03) were less common. Longer intraoperative flow reversal (8.0 ± 1.2 vs 10.5 ± 1.2, p < 0.01) and fluoroscopy time (4.0 ± 0.6 vs 5.1 ± 0.6, p < 0.01) were also seen in those with filter debris. These findings remained when a mixed effect univariate logistic regression model was used to account for differences in filter debris reporting between locations. After multivariable modeling, we found that reverse flow time and CCI remained predictive of filter debris while the presence of a contralateral carotid occlusion was still protective. In our combined experience, the creation of visible filter debris after TCAR seems to be independently associated with extended reverse flow time and elevated CCI while a contralateral carotid occlusion was protective.

Distal end side-to-side anastomosis of sequential coronary bypass for size mismatched saphenous vein grafts and coronary arteries.

The distal end anastomosis is critical to the entire sequential grafts in coronary artery bypass grafting (CABG), but caliber mismatch diminishes the quality of the anastomosis. We aimed to introduce a modified distal end side-to-side (deSTS) anastomosis to handle the size mismatch and compared with classic distal end end-to-side (deETS) anastomosis. From January 2014 to December 2018, 185 patients who underwent off-pump CABG with size mismatched sequential vein grafts (≥3.5mm) and target coronaries (1.0-1.5mm) at the distal end anastomoses were included. We retrospectively reviewed the data of the patients, perioperative and follow-up outcomes were analyzed. The deSTS group (n = 67) showed higher anastomotic flow (19.8 ± 8.0 vs 14.9±6.8mL/min; p < 0.001) and lower pulsatility index (2.7 ± 0.8 vs 3.2 ± 1.0; p = 0.001) than the deETS group (n = 118). Higher incidence of in-hospital myocardial infarction (MI) was found in the deETS group but without significant difference (9.0% vs. 15.3%; p = 0.220). Kaplan-Meier analysis illustrated a relatively lower MI and major adverse cardiovascular and cerebrovascular events (MACCE) incidence in the deSTS group, and the deSTS group was associated with a reduction in long-term death, MI and MACCE in the adjusted Cox regression model. In addition, relatively higher graft patency was found in the deSTS group. The deSTS anastomosis showed superiority in solving size mismatch in sequential CABG, including better intraoperative flow dynamics, ideal long-term graft patency and reduced the incidence of perioperative and follow-up adverse events especially in MI.

Radial artery vs saphenous vein grafts for sequential coronary bypass grafting as a second conduit for the left coronary territory.

Although the radial artery graft has an adaptive property to flow demand, its flow characteristics in aorto-coronary sequential bypass grafting are not well elucidated. We evaluated the differences between the vein and radial artery grafts in the patency and the transit time flow meter-derived parameters (flow and pulsatile index), according to the stenosis rate of terminal target vessels and the number of anastomoses, in sequential bypass grafting to the left coronary territories as a second conduit. We analyzed 222 patients who underwent isolated on-pump beating coronary artery bypass grafting with an aorto-coronary bypass to the left coronary territory. The patients were divided into radial artery group (n = 154) and vein graft group (n = 68). Sequential bypass was performed 1n 171 patients (127 radial arteries, 44 veins). Flow of the radial artery grafts was lower than that of the vein grafts (40.9 ± 22.3 vs 47.5 ± 23.8mL/min, p = 0.044), while it became higher as the number of anastomoses per graft increased (1: 28.9 ± 16.3 vs 2: 40.9 ± 19.9 vs 3: 55.8 ± 27.5, p < 0.001). The patency of radial artery grafts was better than that of vein grafts (98.0% vs 92.6%, p = 0.010; p < 0.001 after propensity score weighting). Although intraoperative flow rate of the radial artery graft is lower, it has sufficient flow reserve for sequential bypass grafting, and its early patency is high enough. Radial artery is suitable for sequential bypass grafting to the left coronary territories as a second arterial conduit.

Utility of indocyanine green videoangiography with FLOW 800 analysis in brain tumour resection as a venous protection technique

BackgroundIn regard to central nervous system tumour resection, preserving vital venous structures to avoid devastating consequences such as brain oedema and haemorrhage is important. However, in clinical practice, it is difficult to obtain clear and vivid intraoperative venous visualization and blood flow analyses.MethodsWe retrospectively reviewed patients who underwent brain tumour resection with the application of indocyanine green videoangiography (ICG-VA) integrated with FLOW 800 from February 2019 to December 2020 and present our clinical cases to demonstrate the process of venous preservation. Galen, sylvian and superior cerebral veins were included in these cases.ResultsClear documentation of the veins from different venous groups was obtained via ICG-VA integrated with FLOW 800, which semiquantitatively analysed the flow dynamics. ICG-VA integrated with FLOW 800 enabled us to achieve brain tumour resection without venous injury or obstruction of venous flux.ConclusionsICG-VA integrated with FLOW 800 is an available method for venous preservation, although further comparisons between ICG-VA integrated with FLOW 800 and other techniques of intraoperative blood flow monitoring is needed.

Risk Factors and Utility of Intraoperative Arteriovenous Fistula Blood Flow Level as a Surrogate Marker of Arteriovenous Fistula Failure in Patients with End-stage Renal Disease.

An arteriovenous fistula (AVF) can fail for different reasons at each stage after its creation. The study aimed to analyze the associations of the clinical and laboratory parameters, including the intraoperative AVF blood flow, with AVF failure at different periods (3 weeks and 3, 6, 9, 12, 24, and 36 months) after the AVF's creation and to evaluate the usefulness of the intraoperative AVF blood flow as a surrogate marker of AVF failure in patients with end-stage renal disease (ESRD). This was a single-center, retrospective cohort study that included 130 patients with ESRD who underwent the creation of new radiocephalic AVFs. The associations of the preoperative clinical and laboratory parameters and intraoperative flow with AVF failure in the different observation periods were investigated. Intraoperative AVF blood flow was significantly associated with AVF failure from 3 weeks to 24 months (P <0.05). Hemoglobin level and the size of the anastomosis were significantly associated with AVF failure at 6 months (P <0.05). In the analysis of the receiver operating characteristic curve, intraoperative AVF blood flow was significant from 3 weeks to 24 months (P <0.05). The intraoperative blood flow with the greatest sensitivity and specificity was 205-225 mL/min. Intraoperative blood flow was independently associated with AVF failure from 3 weeks to 24 months after the AVF's creation. An intraoperative AVF blood flow of >225 mL/min is crucial for long-term AVF patency. The intraoperative AVF blood flow level could be a surrogate marker of AVF failure in ESRD patients.

Intracranial-Intracranial Bypass for Aneurysms: Quantitative Intraoperative Assessment of Flow Preservation.

Intraoperative flow measurement has proven utility in extracranial-intracranial bypass, particularly in assessing the adequacy of donors by measurement of cut flow. The nature of intracranial-intracranial (IC-IC) bypass precludes cut flow measurement, but quantitative intraoperative flow measurements may evaluate augment assessment of the bypass. To retrospectively evaluate flow measurements performed in IC-IC bypass to determine the adequacy of the constructs in preserving flow. With institutional review board approval, we performed a retrospective review of our bypass database from 2001 to 2021 for aneurysms treated with IC-IC bypass and with intraoperative flow measurements. Patients' preoperative characteristics, bypass indications, prebypass and postbypass intraoperative flow measurements, and patient outcomes were recorded. Of 346 bypasses, 21 cases using 22 IC-IC bypasses were included. The median age was 55 years; 13 of 21 cases were ruptured aneurysms. Aneurysms involved posterior inferior cerebellar artery (n = 7), middle cerebral artery (n = 6), distal anterior cerebral artery (n = 5), and anterior communicating artery (n = 3). Six bypasses were end-to-side (ETS), 10 were side-to-side (STS), and 6 were excisional with reanastomosis (end-to-end, ETE). Intraoperatively, 21 of the bypasses were patent; the postbypass/prebypass flow index averaged 1.15 (±0.32): ETE (n = 6) 1.22 ± 0.34 and ETS/STS bypasses (n = 15) 1.11 ± 0.32. All intraoperatively patent bypasses were patent on postoperative angiography. One occluded on delayed angiography without clinical sequelae. Despite advances in endovascular therapy, IC-IC bypass remains essential to the treatment of large and fusiform aneurysms. We demonstrate quantitatively that IC-IC donors provide adequate direct (ETE) and redistributed (STS ETS) flow to the recipient territory. Flow measurement provides valuable information regarding the patency and adequacy of IC-IC bypass for flow preservation.

Quantitative Evaluation of Proliferative Potential Using Flow Cytometry Reveals Intratumoral Heterogeneity and Its Relevance to Tumor Characteristics in Vestibular Schwannomas.

This study sought to explore the existence and clinical significance of intratumoral heterogeneity of proliferative potential in vestibular schwannoma (VS). Rapid intraoperative flow cytometry was utilized with raw samples to measure the proliferative ability of VS. The proliferation index (PI) was defined as the ratio of the number of cells with greater than normal DNA content to the total number of cells. A total of 66 specimens (26 from the intrameatal portion and 40 from the cisternal portion) were obtained from 34 patients with VS. There was a moderate correlation between the PI and MIB-1 labelling index values (R = 0.57, p < 0.0001). In contrast, the patterns of heterogeneity, represented by the proportion of intrameatal PI to cisternal PI, were associated with tumor size (p = 0.03). In addition, preoperative hearing tended to be poor in cases where the intrameatal PI was higher than the cisternal PI (p = 0.06). Our data demonstrated the presence of intratumoral heterogeneity of proliferative potential in VS and its relationship with tumor characteristics. The results of this study may advocate the resection of the intrameatal portion of large VSs treated with planned subtotal resection, especially in cases of poor preoperative hearing function.

Transit Time Flow Measurement in Robotic Totally Endoscopic Coronary Artery Bypass: What Do the Numbers Mean?

Transit time flow measurement (TTFM) is valuable for assessing intraoperative graft patency in coronary artery bypass surgery (CAB). The significance of competitive native coronary flow on patency, as predicted by percentage of backflow (%BF) on TTFM, is unknown. This study aims to evaluate intraoperative TTFM parameters, and specifically %BF, in predicting graft patency in robotic totally endoscopic CAB (TECAB). We reviewed TTFM parameters in 311 patients undergoing robotic off-pump TECAB at our institution between February 2016 and January 2020. Patients with sequential or Y grafts were excluded, leaving 277 patients with a total of 387 isolated end-to-side grafts (248 left internal mammary artery [LIMA], 149 right IMA [RIMA]). Mean graft flow, diastolic flow, pulsatility index, and %BF were measured intraoperatively. Early postoperative angiograms were obtained in 83 patients undergoing percutaneous coronary intervention for hybrid revascularization, with a total of 125 grafts. Angiograms were independently analyzed and separated into 2 groups based on IMA graft patency, which were patent (FitzGibbon A/B) and nonpatent (FitzGibbon O) groups. Early angiographic patency at a median of 31.0 days after surgery showed 123 (97.1%) patent grafts and 3 (2.9%) occluded grafts in both LIMA and RIMA grafts to both left anterior descending (LAD) and non-LAD targets. Mean graft flow was 77.4 ± 41.6 mL/min. There was no difference in mean flow, pulsatility index, or %BF between the patent and occluded grafts. Excellent intraoperative flow parameters and early angiographic patency can be obtained via robotic, off-pump TECAB. Our data did not demonstrate an association between intraoperative TTFM evidence of competitive native coronary flow and early angiographic graft outcomes.

Hepatobiliary-pancreatic surgery for patients with a prepancreatic postduodenal portal vein: a case report and literature review

BackgroundPrepancreatic portal vein (PPV) is a congenital anatomical variant of the portal vein (PV). PPVs are extremely rare and generally classified into two categories, prepancreatic preduodenal portal vein and prepancreatic postduodenal portal vein (PPPV). Prepancreatic preduodenal portal veins are rare, with approximately 100 reported cases globally; PPPVs are even more atypical, with less than 20 documented cases globally. Despite the extremely low occurrence, PPPV knowledge and recognition are important, especially for hepatobiliary-pancreatic (HBP) surgeries, such as pancreaticoduodenectomy (PD) for patients of a PPPV. Here, we report a case of PPPV and a literature review.Case presentationA 73-year-old-male with ampullary carcinoma underwent PD at our hospital. Preoperative enhanced CT revealed an abnormal L-shaped PV, identified as a PPPV. Both the PPPV and the postpancreatic “normal” superior mesenteric vein (SMV) divaricated from the SMV at the caudal side of the pancreas. A splenic vein and inferior mesenchymal vein flowed into the postpancreatic “normal” PV, which encircled the common bile duct and potentially flowed into the liver, forming a cavernous transformation at the hilar plate. During surgery, we attempted to isolate the PV from the pancreas and common bile duct. However, it was difficult to isolate from the pancreas. The PPPV was so fragile that bleeding from the PPPV became uncontrollable. To remove the tumor, we resected the PPPV and reconstructed a “normal” PV as an autogenous graft. To maintain intraoperative hepatic blood flow and avoid small bowel congestion, an antithrombogenic bypass catheter was placed between the SMV and umbilical vein during reconstruction. After surgery, several complications occurred, such as PV thrombosis and hyperammonemia. The patient was discharged on postoperative day 45.ConclusionsPPPV is a rare vascular variant but is easily diagnosed preoperatively due to its distinct shape on CT imaging. However, isolating the PPPV from the pancreas and bile duct is incredibly difficult and potentially associated with increased operative risks and postoperative complications. PV resection rather than isolation is a potential solution to reduce the risk of hemorrhage, even in the absence of invasion.

Intraoperative flow cytometry for invasive breast cancer conserving surgery: A new alternative or adjunct to cavity shaving technique?

Intraoperative flow cytometry for invasive breast cancer conserving surgery: A new alternative or adjunct to cavity shaving technique?

Abstract TMP80: Intraoperative Blood Flow Changes Predict Angiographic Outcomes After Direct Cerebral Revascularization For Moyamoya Disease

Introduction: Moyamoya Disease (MMD) is a progressive steno-occlusive vasculopathy of the large intracranial vessels precipitating ischemic and hemorrhagic events. Cerebral revascularization is the mainstay of treatment in MMD. Intraoperative measurements of cerebral blood flow following direct intracranial bypass may be performed to quantitatively assess the anastomosis. Objectives: To correlate intraoperative flow parameters in direct cerebral bypass for moyamoya disease to postoperative angiographic and clinical outcomes. Methods: Consecutive patients undergoing direct superficial temporal artery (STA) to middle cerebral artery (MCA) bypass were retrospectively analyzed. Preoperative and 6-month postoperative patient data was collected including presenting symptoms, MRI and angiographic findings, neurological complications, and functional outcome. Intraoperative cerebral blood flow was measured from the donor and recipient arteries using a micro flow probe pre- and post-anastomosis. Results: A total of 50 direct revascularization procedures in 39 patients were analyzed, of which 40 were in females (80%). The mean flow prior to anastomosis in the M4 MCA was +2.2 ± 6.1 ml/minute and +26.8 ± 19.0 ml/min in the STA. Post-anastomosis, the mean flow was -10.9 ± 14.8 ml/min (towards the Sylvian Fissure) in the proximal M4 and +7.9 ± 9.2 ml/min in the distal M4. At 6-month follow-up angiography, the graft was patent in all cases, with 98% demonstrating direct supply. A component of indirect supply was observed in 56% of grafts. Matsushima grade A, B, and C revascularization were obtained in 64%, 20%, and 16% of cases, respectively. Amongst Matsushima grade A patients, low flow was observed in the M4 (mean 1.7 ± 4.8 ml/min) prior to bypass, which became retrograde following bypass, measuring -13.5 ± 16.0 ml/min. Lower post bypass flow was observed in grade B and C patients, with -6.8 ± 13.1 ml/min and -5.6 ± 10.3 ml/min, respectively. Postoperative stroke occurred in one patient, who had a Matsushima grade C. Conclusions: Greater intraoperative retrograde flow in the recipient MCA immediately following anastomosis was observed in patients achieving a higher Matsushima grade.

Intraoperative Hemodynamic Monitoring and Management

Postoperative deaths are a consequence of postoperative complications - including acute kidney injury and myocardial injury. Postoperative complications are associated with non-modifiable patient-specific risk factors (i.e., age, medical history), but also with potentially modifiable risk factors - including intraoperative hypotension and compromised intraoperative blood flow. Based on patient- and surgery-specific risk factors, the intraoperative hemodynamic monitoring strategy needs to be selected. Intraoperative hypotension is associated with postoperative organ failure and should thus be avoided. To optimize intraoperative hemodynamics, cardiac output-guided hemodynamic management has been proposed. Cardiac output-guided hemodynamic management aims at optimizing oxygen delivery using fluids, vasopressors, and inotropes. Cardiac output-guided hemodynamic management has been shown to reduce postoperative complications compared to routine hemodynamic management in high-risk patients having major surgery.

Outcomes of Autogenous Radiocephalic Versus Brachiocephalic Arteriovenous Fistula Surgery Based on Transit-Time Flowmeter Assessment: A Retrospective Study

Despite the better operative results of autogenous brachiocephalic arteriovenous fistula (BC-AVF), it is considered secondary to autogenous radiocephalic AVF (RC-AVF) failure. Here we compared the results of our multidisciplinary management protocol of BC-AVF versus RC-AVF. A total of 194 matched patients who requested autogenous BC-AVF or RC-AVF surgery between 2017 and 2019 were included in this retrospective study. All patients strictly adhered to our departmental perioperative management protocol for AVF surgery, including vessel status monitoring, exercise with or without a tourniquet, intraoperative flow assessment, and antiplatelet and anticoagulant medications. AVF function and patient status data were acquired from the electronic medical records, and the final evaluation was made via outpatient department visit or phone call in October 2020. Patients who underwent elective BC-AVF or RC-AVF (n=97 each) were included. The patient groups had similar preoperative clinical characteristics. Artery and vein sizes at the planned anastomosis site were larger in the BC-AVF group (P < 0.001). The mean intraoperative maximal flow rate was higher in the BC-AVF group (492.5 ± 186.9 mL/min) than in the RC-AVF group (307.3 ± 113.0 mL/min, P < 0.001). The simultaneously evaluated mean pulsatility index was 0.5 ± 0.2 in the BC-AVF group and 0.6 ± 0.2 in the RC-AVF group (P < 0.001). The median observation duration was 19.4 months (11.0‒31.3 months). The primary patency rate was higher in the BC-AVF group (88.7%) than in the RC-AVF group (62.9%, P < 0.001). Patency duration was similar between groups, and the primary patency maintenance duration was longer in the BC-AVF group. Three cases of cephalic arch stenosis were observed in the BC-AVF group, while no cases of arterial steal syndrome were observed during the indexed observation period. Mortality rates were 14.4% and 9.3% in the BC-AVF and RC-AVF groups, respectively (P=0.267), and the cause of death did not differ significantly between groups. For mortality, the estimated hazard ratio of RC-AVF over BC-AVF was 0.47 (95% CI, 0.19‒1.17, P=0.106) during the observation period. BC-AVF had good characteristics for hemodialysis without an increased risk of AVF related complications during a median 19-month observation period. BC-AVF did not feature high flow-related complications with the multimodal approach, including preoperative exercise, intraoperative flow assessment to guarantee an adequate flow rate, postoperative exercise, and medications.

Three-step operation for esophago-left bronchial fistula with respiratory failure after esophagectomy: a case report with literature review

BackgroundThe development of esophago-bronchial fistula after esophagectomy and reconstruction using a posterior mediastinal gastric tube remains a rare complication associated with a high rate of mortality.Case presentationA 63-year-old man with esophageal cancer underwent a thoracoscopic esophagectomy with two-field lymph node dissection and reconstruction via a gastric tube through the posterior mediastinal route. Postoperatively, the patient developed extensive pyothorax in the right lung due to port site bleeding and hematoma infection. Four months after surgery, he developed an esophago-left bronchial fistula due to ischemia of the cervical esophagus and severe reflux esophagitis at the site of the anastomosis. Because of respiratory failure due to the esophago-bronchial fistula and the history of extensive right pyothorax, right thoracotomy and left one-lung ventilation were thought to be impossible, so we decided to perform the surgery in three-step systematically. First, we inserted a decompression catheter and feeding tube into the gastric tube as a gastrostomy and expected neovascularization to develop from the wall of the gastric tube through the anastomosis after this procedure. Second, 14 months after esophagectomy, we constructed an esophagostomy after confirming blood flow in the distal side of the cervical esophagus via gastric tube using intraoperative indocyanine green-guided blood flow evaluation. In the final step, we closed the esophagostomy and performed a cervical esophago-jejunal anastomosis to restore esophageal continuity using a pedicle jejunum in a Roux-en-Y anastomosis via a subcutaneous route.ConclusionThis three-step operation can be an effective procedure for patients with esophago-left bronchial fistula after esophagectomy, especially those with respiratory failure and difficulty in undergoing right thoracotomy with left one-lung ventilation.

Intraoperative transit time flow measurement in patients with diffuse coronary artery disease in the prevention of aortocoronary bypass graft occlusion

Aim. To study the parameters of transit time flow measurement (TTFM) for coronary bypass grafts in patients with diffuse lesions with different diameter of target coronary arteries.Material and methods. The study included 150 patients with diffuse coronary artery disease. All patients underwent microscope-assisted coronary artery bypass grafting (CABG), during which the TTFM parameters were evaluated. Depending on the diameter of target coronary arteries, patients were divided into 3 groups: group 1 included grafts to arteries ≤1 mm (n=101), group 2 — 1-1,5 mm (n=138), group 3 — ≥1,5 mm (n=308). Comparative analysis of TTFM parameters was performed.Results. Mostly participants were male (76%); mean age was 62,9±7,6 years. During hospitalization, we recorded 1 death, 2 perioperative myocardial infarctions (1,3%) and 1 cerebrovascular accident (0,7%). TTFM analysis showed the worst hemodynamic parameters and a higher rate of suboptimal function in group 1; blood flow parameters were comparable in groups 2 and 3. The additional analysis in group 1 and combined groups 2 and 3 allows us to make an opinion about the negative impact of coronary artery diameter less than 1 mm on optimal blood flow through the grafts (odds ratio=2,1, 95% confidence interval, 1,2-3,8, p=0,011).Conclusion. Diffuse coronary atherosclerosis with a diameter of target coronary arteries less than 1 mm significantly increase the risk of suboptimal graft function that requires considering more aggressive secondary prevention. TTFM demonstrate high effectiveness of microscope-assisted CABG in target coronary artery diameter of 1-1,5 mm and higher.