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Cardiac Cases
The cardiac case for May features a case report published by Jien Saito et al.1 from Nagoya City University East Medical Center in Japan. The report is called “Management of Coronary Artery Bypass Grafting Using an Arteriovenous Fistula: An Intraoperative Change in the Preoperative Plan”. The patient was a 78-year-old man with end-stage renal disease who experienced angina pectoris during hemodialysis. A coronary angiography showed a two-vessel lesion, including the left main coronary trunk. Ultrasound measurement of flow in the AVF showed high flow: 1.132 mL/min. The Preoperative plan was to perform an Off-pump CABG with LITA to LAD, RITA to the high lateral branch (HL), and an SVG to the posterolateral branch. Based on the finding that the free flow of in in-situ LITA was 20 mL/minute with a weak pulsation, the team was concerned it would be insufficiency for revascularization of the LAD with high flow demand, and they revised the preoperative plan to anastomose RITA to LAD instead. They also evaluated LITA after anastomosis to HL. After completion of all anastomoses, as feared, the LITA graft demonstrated retrograde blood flow, which suggested the occurrence of ITA anomalies or subclavian steal. TTFM of LITA-High lateral branch before re-anastomosis shows a retrograde flow pattern in systole. the low flow of the LITA and high flow in the AVF indicated that the original blood flow of the LITA might have been drawn into the AVF, see image 1. The LITA graft was transected at the proximal part and anastomosed to the saphenous vein graft with sufficient flow to reach the HL (14 mL/minute) as a Y-composite graft. Postoperative angiography showed good patency of all bypass grafts. The patient was discharged from the hospital 16 days after surgery. See image 3: Free LITA-LAD graft after re-anastomosis and TTFM shows 14 mL/minute and reduced PI. In this case TTFM helped the surgeons make the decision to use LITA as a free graft after a measurement on the in-situ LITA. Resulting in an increase of flow from negative to 14 mL/min and reducing PI from 12.2 to 2.2. For CABG in a patient on hemodialysis with an AVF, the blood flow of the AVF and free flow of the ipsilateral ITA are regarded as predictive factors of coronary subclavian steal syndrome occurrence. However, they do not represent decision factors. The ipsilateral ITA may be used as a free graft and not as an in-situ graft in cases where there are concerns about ipsilateral ITA blood flow to prevent subclavian steal. Link to full article: https://www.cureus.com/articles/141489-management-of-coronary-artery-bypass-grafting-using-an-arteriovenous-fistula-an-intraoperative-change-in-the-preoperative-plan#!/ -
Vascular Cases
This case illustrates how ultrasound imaging enables more correct detection of higher-grade defects than angiography after CEA. The case is provided by the authors of the CIDAC Study. -
Cardiac Cases
This month the Cardiac case highlights a recent study performed at the University hospital in Essen, Germany and published in Journal of Cardiovascular Development and Disease (JCDD). The study is titled “Role of Antiplatelet Therapy in Patients with Severe Coronary Artery Disease Undergoing Coronary Artery Endarterectomy within Coronary Artery Bypass Surgery”. Dual antiplatelet therapy (DAPT) is indicated as “could protect against fast intimal ingrowth after injuring procedures by PCI” by the ESC/EACTS- and ACC/AHA-guidelines. The 2017 EACTS guidelines on perioperative medication also recommends considering DAPT for patients undergoing coronary bypass grafting (CABG). With these guidelines as background, the featured study aimed to review the effect of single-APT or dual-APT on a population of 353 patients undergoing coronary artery endarterectomy (CEA) as part of a CABG procedure.Surgical Procedure
All surgeries were performed on-pump using cardiopulmonary bypass (CPB), under arrested heart after administration of crystalloid cardioplegia. Coronary endarterectomy was performed in the case of total or sub-total occlusion (i.e., if the vessel’s lumen < 1.25 mm). The applied CEA-technique was a modified closed-traction technique and consisted of five steps. A proper removal of the atheroma was considered when a smoothly tapered cylinder was extracted (Figure 1), otherwise a distal second incision and subsequent anastomosis was performed to guarantee adequate revascularization of the peripheral segments. After creation of the anastomosis with the chosen graft, transit time flow measurement (TTFM) was performed to control the graft function (Figure 1).
With regards to the flow measurements the study says:
In this study, coronary bypass flow was significantly higher in DAPT patients than in SAPT patients (65 (45–90) vs. 57 (35–80) mL/minute, p = 0.028), as proven by TTFM measurements after discontinuation of CPB, even though this finding was only observed retrospectively, graft flow should be considered for long-term graft patency evaluation. As expected, most of the occluded grafts were venous (37 out of 45 of the total grafts and 15 out of 17 of the CEA grafts), which corresponds to previous reports observing better arterial graft patency in comparison to the venous ones [28,29]. A probable explanation for graft patency might be the role of early DAPT therapy starting at the first postoperative day using ASA + P2Y12-inhibitor for six months.
Long-term outcomes reported in the study demonstrated a significant lower incidence of overall mortality (19% vs. 51%, p < 0.0001) and MACCE (24.5% vs. 58.2%, p < 0.0001) in the DAPT versus SAPT group, respectively, as reported in Kaplan Meier curves for the estimation of survival and freedom from MACCE (Figure 4).
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Vascular Cases
Based on his extensive experience using Transit Time Flow Measurement (TTFM) and High-Frequency Ultrasound (HFUS) during vascular surgery, Dr. Alexander Meyer published a study in 2019 called, "Determinants of successful arteriovenous fistulae creation including intraoperative transit time flow measurement" 1. Subsequently, in 2022 Dr. Meyer collaborated with Medistim to create a recommended workflow for quality control during forearm fistula creation. This workflow is informed by Dr. Meyer's experience and available clinical data, which includes the aformentioned 2019 publication.Recommended workflow for quality control during AV fistula creation
As a result of Dr. Meyer’s years of experience in vascular surgery, he developed this recommended AV Access workflow.2
This workflow is developed for creation of forearm fistulas but can in principle also be used for brachiocephalic fistulas. Note that the recommended blood flow volume in upper arm fistulas might be higher than for forearm fistulas.
Publication Abstract
Background
The prevalence of hemodialysis patients is increasing, and it is important to create the arteriovenous fistula as early as possible to avoid hemodialysis by central venous catheter. International guidelines recommend arteriovenous fistula as the vascular access of first choice. Arteriovenous fistulae are associated with a failure rate of 23%. The success of an arteriovenous fistula can be evaluated intraoperatively by physical examination and by measuring the blood flow.Objectives
The aim of the study is to describe the predictive value of various factors for fistula maturation in the context to the current literature.Methods
We report on a prospective cohort study of 41 patients, undergoing a primary arteriovenous fistula at the upper extremity. The primary endpoint of the study was the successful fistula maturation after 6 weeks.Results
The intraoperative measurement of the blood flow in the outflow vein has been identified as the unique significant parameter for the fistula maturation.Conclusions
The predictive value of intraoperative flow measurement is superior to intraoperative physical examination and could help reduce the fistula dysmaturation rate. Intraoperative transit time flow measurement is an easy method and can be used to predict successful fistula maturation in a high percentage rate -
Vascular Cases
Performing quality control during peripheral bypass surgery is important to secure optimal patency of the graft to avoid re-operation or secondary intervention. In this case, Transit Time Flow Measurement (TTFM), High-Frequency Ultrasound (HFUS), and angio verified distal flow before closing the wounds.Patient information
• 67-year-old male • Occlusion of the left superficial femoral artery • Vascular ulcer above left ankle (Figure 1) -
Cardiac Cases
This cardiac case highlights a very interesting paper called: "Epicardial Ultrasound in a Case of Myocardial Bridge and Apical Hypertrophic Cardiomyopathy" by Lindsey Whalen, Stephen Davies, Karen Singh, and Gorav Ailawadi. In this case, the surgical team used HFUS to identify the myocardial bridge and confirm resolution of the compression. Furthermore, epicardial ultrasound was used for guiding the degree of apical resection on the decompressed heart. -
Cardiac Cases
Knowing whether an underperforming conduit should be rejected or not is very valuable information. This case from the Request Study describes how the combined use of Transit Time Flow Measurement (TTFM) and High-Frequency Ultrasound (HFUS) allowed the surgeon to make informed decisions before proceeding. -
Vascular Cases
This case demonstrates how Transit Time Flow Measurement (TTFM) can be used during liver transplant surgery as a guide when modulating the portal venous flow (PVF) to avoid hepatofugal flow. Hepatofugal flow or non-forward portal flow (NFPF) describes a blood flow that is directed away from the liver. Hepatofugal flow in the portal venous system is, with few exceptions, always pathological. Detection of NFPF is important as it has been shown to be associated with poorer clinical outcome after liver transplantation. See image 1 -
Cardiac Cases
Graft patency verification can be difficult in cases with competitive flow. This case from the Request Study describes how the combined use of Transit Time Flow Measurement (TTFM) and High-Frequency Ultrasound (HFUS) allowed the surgeon to make informed decisions about how to proceed. -
Vascular Cases
This case demonstrates how High-Frequency Ultrasound (HFUS) can detect thrombus in the hepatic artery even when Transit Time Flow Measurement (TTFM) did not reveal any flow related issues. The case example consists only of a set of measurements and images using the MiraQTM during the surgery without further comments from the surgeon. -
Vascular Cases
This case demonstrates how Transit Time Flow Measurement (TTFM) can be used during liver transplant surgery to detect technical errors. -
Cardiac Cases
"Great benefit in graft patency verification. Very accurately able to detect dissection as the problem." (Ref. operating surgeon) This case from the Request Study describes how the combined use of Transit Time Flow Measurement (TTFM) and High-Frequency Ultrasound (HFUS) revealed a dissected LIMA. These insights helped the surgeon identify the issue and address it appropriately. Pre-Op Angio indicated that the patient had a moderate to severe lesion (50-75%) proximally in the LAD, CX was calcified proximally, and the RCA was occluded proximally. -
Cardiac Cases
This case from the REQUEST Study describes how the combined use of Transit Time Flow Measurement (TTFM) and High frequency ultrasound (HFUS) revealed a compromised graft. These insights helped the surgeon identify the issue and address it appropriately. The patient had a 40% main stem stenosis, an EF% of 60, and was scheduled for an on-pump CABG with two grafts.- LIMA-LAD
- SVG-OM
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Vascular Cases
This case demonstrates how Transit Time Flow Measurement (TTFM) and High-Frequency Ultrasound (HFUS) were instrumental in avoiding a catastrophic incident. A thrombus in the saphenous vein graft (SVG) was detected during surgery. Meso-Rex shunt is a surgical procedure that restores physiological portal venous blood flow to the liver by using a graft to connect the superior mesenteric vein and the left portal vein within the Rex recess. -
Cardiac Cases
This case from the REQUEST Study describes how the combined use of Transit Time Flow Measurement (TTFM) and High frequency ultrasound (HFUS) revealed a compromised anastomosis, enabling the surgeon to handle the situation appropriately. The patient was originally scheduled for an on-pump CABG with three grafts:- LIMA-DIAG-LAD
- LIMA-Y-RIMA-OM-PL
- SVG-PDA
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Vascular Cases
This case shows the benefit of using Transit Time Flow Measurement (TTFM) in addition to High-Frequency Ultrasound (HFUS) after CEA when dealing with a kinked ICA. Finding kinks like these before performing CEA are not uncommon in elderly people. The surgeon decided not to repair the kink since it could result in more kinks upstream causing further problems. Nor did he shorten the artery since it might increase the risk of creating an unwanted flap. When he measured the flow with TTFM after CEA, he found it satisfactory hence avoiding further revision. -
Cardiac Cases
This case illustrates how High-frequency Ultrasound Imaging (HFUS) can be used to identify or locate aortic dissections. Early discovery and precise location of this highly critical incident can be very significant to the outcome of the procedure. -
Vascular Cases
This case shows that the expectation of a huge increase in flow is not always met in every case. However, a significant change in the flow curve can be seen. HFUS revealed intima flaps that are not visible on angiography. When checking the clamping sites and the intima steps in the ICA and ECA after CEA, minor residual intima flaps were detected but did not lead to a revision. -
Cardiac Cases
This case from the REQUEST Study illustrates how High-frequency Ultrasound Imaging (HFUS) can be used to identify soft, non-palpable plaque in the aorta, thus avoiding unnecessary manipulation of the affected areas. Detecting this potential issue allowed the surgeon to change the plan accordingly. Patient information and past medical history:77-year-old male, BMI 24.1 -
Vascular Cases
Patient medical history: Patient with PAD and Fontaine stage IV on the right side. See image 1. Initial surgery: Fem-pop bypass. The surgery went uneventfully and the TTFM showed 41 ml/min with a PI of 2,9 after ligation of all residual saphenous vein side branches that were visible on angio, as seen in image 2. -
Cardiac Cases
This case illustrates how High-frequency Ultrasound Imaging (HFUS) can be used during surgery to identify plaque in the aorta, avoid complications, and improve graft patency. -
Vascular Cases
This case illustrates a low-flow situation of a Cimino fistula on the left forearm with a juxta-anastomotic stenosis. Transit Time Flow Measurement (TTFM) and High-frequency Ultrasound Imaging (HFUS) served as completion control. -
Vascular Cases
This case example shows a routine fem-pop case where the surgeon assessed the quality of the bypass procedure using all 3 measurement technologies provided by the MiraQ system; High-frequency ultrasound imaging, TTFM and PW Doppler measurements. -
Cardiac Cases
This case illustrates how High-frequency Ultrasound Imaging (HFUS) can be used during surgery to detect intramural vessels, to avoid complications, and improve graft patency. -
Vascular Cases
This case illustrates how ultrasound imaging enables more correct detection of higher-grade defects than angiography after CEA. The case is provided by the authors of the CIDAC study. -
Cardiac Cases
This case illustrates how High-frequency Ultrasound Imaging (HFUS) can be used during surgery to detect unexpected issues with the conduit to avoid complications and improve graft patency.
Watch this space for future monthly cardiac and cascular cases