Vascular Interventional Surgery Research Articles

Illness Beliefs and Walking Behavior After Revascularization for Intermittent Claudication

Patients with peripheral artery disease (PAD) are recommended to increase physical activity to reduce cardiovascular risk. Vascular intervention (surgery or angioplasty) treats the symptom (intermittent claudication), but not the underlying cardiovascular disease. This study aims to explore the beliefs and physical activity behavior of patients with PAD who have received vascular intervention. Twenty participants who had received a vascular intervention for intermittent claudication between 6 months and 2 years previously participated in semistructured interviews. The interviews explored illness and treatment beliefs and walking behavior. Data were transcribed verbatim and analyzed thematically. Participants described a high level of ongoing symptoms (particularly pain) in their legs, despite having received vascular intervention. They viewed their illness as acute and treatable, and believed that pain was an indication of walking causing damage. They controlled their symptoms by avoiding walking and slowing their pace. Participants were generally unaware of the causes of the disease and were unaware of their increased risk of future cardiovascular health problems. There was a low level of congruence between participant beliefs about their illness and the recommendation to increase physical activity that may affect physical activity behavior. Our findings suggest that patients with PAD do not change physical activity behavior after diagnosis and treatment, because they hold dysfunctional and incongruous beliefs about PAD, treatment, and physical activity.

Performance optimization of force feedback control system in virtual vascular intervention surgery.

In virtual surgery of minimally invasive vascular intervention, the force feedback is transmitted through the flexible guide wire. The disturbance caused by the flexible deformation would affect the fidelity of the VR (virtual reality) training. SMC (sliding mode control) strategy with delayed-output observer is adopted to suppress the effect of flexible deformation. In this study, the control performance of the strategy is assessed when the length of guide wire between actuator and the operating point changes. The performance assessment results demonstrate the effectiveness of the proposed method and find the optimal length of guide wire for the force feedback control.

Acute Testicular Ischemia following Endovascular Abdominal Aortic Aneurysm Repair Identified in the Emergency Department.

Endovascular aneurysm repair (EVAR) is perhaps the most widely utilized surgical procedure for patients with large abdominal aortic aneurysms. This procedure is minimally invasive and reduces inpatient hospitalization requirements. The case involves a 72-year-old male who presented to the emergency department with right testicular ischemia two days following EVAR. Given the minimal inpatient hospitalization associated with this procedure, emergency physicians are likely to encounter associated complications. Ischemic and thromboembolic events following EVAR are extremely rare but require prompt vascular surgery intervention to minimize morbidity and mortality.

Clinical characteristics associated with readmission among patients undergoing vascular surgery

Readmission after a vascular surgery intervention is frequent, costly, and often considered preventable. Vascular surgery outcomes have recently been scrutinized by Medicare because of the high rates of readmission. We determined patient and clinical characteristics associated with readmission in a cohort of vascular surgery patients. From 2009 to 2013, the medical records of all patients (n = 2505) undergoing interventions by the vascular surgery service at a single tertiary care institution were retrospectively reviewed. Sociodemographic and clinical characteristics were examined for association with 30-day readmission to the same institution. The 30-day readmission rate to the same institution was 9.7 % (n = 244). Procedures most likely to result in readmission were below-knee (25%), foot (22%), and toe amputations (19%), as well as lower extremity revascularization (22%). Patients covered by Medicaid (16.8%) and Medicare (10.0%) were most likely to be readmitted, followed by fee-for-service (9.5%), self-pay (8.0%), and health maintenance organizations (5.5%; P < .05). Patients urgently admitted were more likely to be readmitted (16.2%) than those electively admitted (9.1%; P < .01). Patient severity as rated using the All Patient Refined Diagnosis Related Groups software (3M Health Information Systems, Wallingford, Conn) predicted readmission (16.2% high vs 6.2% low severity; P < .01). Initial length of stay was longer for readmitted than nonreadmitted patients (8.5 vs 6.1 days, respectively; P < .01). Intensive care unit admission during the initial hospitalization was associated with higher readmission rates in univariable analysis (18.3% with vs 9.5% without intensive care unit stay; P < .05). Discharge destination was also a strong predictor of readmission (rehabilitation, 19.2%; skilled nursing facility, 16.2%; home, 6.2%; P < .01). The effects of urgent admission, proximity to hospital, length of stay, lower extremity open procedure or amputation, and discharge destination persisted in multivariable logistic regression (P < .05). To reduce readmission rates effectively, institutions must identify high-risk patients. Efforts should focus on subgroups undergoing selected interventions (amputations, lower extremity revascularization), those with urgent admissions, and patients with extended hospital stays. Patients in need of postacute care upon discharge are especially prone to readmission, requiring special attention to discharge planning and coordination of postdischarge care. By focusing on subgroups at risk for readmission, preventative resources can be efficiently targeted.

A remote‐controlled vascular interventional robot: system structure and image guidance

Robot-assisted vascular interventional surgery (VIS) enables the surgeon to teleoperate a catheter in a safe cabinet, such that exposure to X-ray radiation is reduced. For safe and accurate teleoperation, system structure and image guidance is important. The system structure of the developed remote-controlled vascular interventional robot (RVIR) and its image guidance system (IGS) are introduced. RVIR is based on a master-slave structure. Key technologies of IGS are addressed, including C-arm calibration, distortion correction, catheter localization and 3D vasculature reconstruction. Experiments show that the RMS error of distortion correction is 0.35 pixels, and 0.53 mm for distance reconstruction. The error in catheter localization between the IGS and the encoders is small. In vitro and in vivo tests verified the feasibility of RVIR. Experiments indicate that the RVIR is feasible and valid to help the surgeon perform VIS remotely; the function and reconstruction accuracy of IGS can satisfy the surgeon's requirement to guide the RVIR.

Fuzzy Fusion of Forces Feedback in Vascular Interventional Surgery Robot System

In order to consummate the master-slave robot system used in vascular interventional procedures,a closed loop of force is rebuilt.Two micro force sensors are integrated with a catheter,which can measure those forces between the tip or side wall of the catheter and vascular walls respectively at the same time.Given that the master-slave mode is different from the traditional hands-on operation and that it is necessary to ensure the sustained effect of the valuable experience from surgeons,a two-input one-output model in fuzzy inference is adopted to accomplish the fusion of the two sensors’ data.By means of calibrating membership functions and establishing a table of fusion rules,experience is converted into numerical strategies about the force feedback,which not only improves the force reflection under low sampling rate,but also characterizes collisions accurately with different resolutions.It ensures the safety,applicability and efficiency of the robot system.

A novel robotic catheter system with force and visual feedback for vascular interventional surgery

This paper proposes a novel master-slave robotic catheter operating system with force feedback and visual feedback for vascular interventional surgery (VIS). The robotic catheter system has good manoeuvrability, it can transmit the surgeon’s skill to insert and rotate the catheter and avoids danger during VIS using force and visual feedback. In addition, it can be used to train unskilled surgeons to perform VIS. We performed a simulation experiment to validate our system using an endovascular evaluator (EVE). The experimental results demonstrated that the stability and response of the system were good. The robotic catheter system is suitable for performing VIS.

Catheter-directed thrombolysis in inflammatory bowel diseases: Report of a case

In patients with inflammatory bowel diseases (IBD) the prevalence of thrombosis is 6.2%, the average incidence of thromboembolism (TE) is 3.6 times higher compared to normal population. The TE is a common extraintestinal complication of IBD, squarely associated with the IBD activity. The application of anticoagulant and thrombolytic therapy in severe IBD is an unresolved issue. Herein we report the first case in literature of an active IBD patient with an upper limb acute arterial occlusion and successful catheter-directed thrombolysis (CDT). A 46-year-old male patient is reported who had Crohn's disease for 10 years. His right hand suddenly became cold and painful. Angiography proved acute occlusion of the brachial and radial artery. Vascular surgery intervention was not applicable. Endoscopy showed extended, severe inflammation of the colon. Despite the severe endoscopic findings, frequent bloody stools and moderate anaemia, CDT with recombinant tissue plasminogen activator was performed. The control angiography proved improvement, the radial artery pulse appeared. No bleeding complication was observed. This case supports that CDT-after careful estimation of the bleeding risk-can be effective and safe in patients with severe or life-threatening TE and active IBD.

Design of the Control System and Home Point Positioning Device for Minimally Invasive Vascular Interventional Surgery Robot

To realize the accurate positioning and stable holding of surgical tools by minimally invasive vascular interventional surgery(VIS) robot,a control system and a home point positioning device are designed.Constitutions of the robot system and its upper-lower control system based on PMAC(programmable multi-axis controller) are introduced firstly. Meanwhile,the quintic interpolation motion planning and three-loop PID algorithms are designed,which improve both the robot's response speed and stability.To find the base point of the robot's motion,the home point positioning method and device are proposed based on Hall sensors and information of motor motion.The experiment results show that the presented home point positioning device works stably and accurately.

Managing perceived conflicts of interest while ensuring the continued innovation of medical technology

If it were not for the ongoing collaboration between vascular surgeons and the medical technology industry, many of these advanced treatments used every day in vascular interventional surgery would not exist. The flip side of this coin is that these vital relationships create multiple roles for surgeons and must be appropriately managed. The dynamic process of innovation, along with factors such as product delivery technique refinement, education, testing and clinical trials, and product support, all make it necessary for ongoing and close collaboration between surgeons and the device industry. This unique relationship sometimes leads to the perception of conflicts of interest for physicians, in part because the competing pressures from the multiple, overlapping roles as clinician/caregiver/investigator/innovator/customer are significant. To address this issue, the Advanced Medical Technology Association (AdvaMed), the nation's largest medical technology association representing medical device and diagnostics companies, developed a Code of Ethics to guide medical technology companies in their interactions with health care professionals. First introduced in 1993, the AdvaMed Code strongly encourages both industry and physicians to commit to openness and high ethical standards in the conduct of their business interactions. The AdvaMed Code addresses many of the types of interactions that can occur between companies and health care professionals, including training, consulting agreements, the provision of demonstration and evaluation units, and charitable donations. By following the Code, companies send a strong message that treatment decisions must always be based on the best interest of the patient.

Application study of medical robots in vascular intervention

Based on the background of minimally invasive surgery and applications of medical robots, a vascular interventional robotic system has been developed that can be used in the field of vascular intervention. The robotic system comprises a propulsion system, an image navigation system and a virtual surgery training system. Integration of the three systems constitutes a vascular intervention prototype robotic system used to carry out in vitro vascular intervention and animal experiments. On a transparent glass vascular model, a catheter was shown to enter an arbitrary branch of the vascular model with catheter motion meeting the requirements of clinical vascular intervention surgery (VIS); i.e. error band of catheter motion < 0.5 mm. In the animal experiments, 1.33-2.00 mm (4F-6F) diameter catheters were selectively inserted successfully into predefined targets in the animal, such as the renal, cardiovascular and cerebrovascular artery. Compared with conventional manual surgery, the time for robotic surgery is a little longer. There were no operative complications in the animal experiments. These simulation and animal study results demonstrate that this vascular interventional robotic system allows doctors to perform angiography remotely and prevents them from radiation exposure. The system may be the basis for further clinical applications of vascular intervention.

Defining the Optimal Degree of Heparin Anticoagulation for Peripheral Vascular Interventions

Background— The optimal degree of heparin anticoagulation for peripheral vascular interventions (PVIs) has not been defined. We sought to correlate total heparin dose and peak procedural activated clotting time (ACT) with postprocedural outcomes in patients undergoing PVI. Methods and Results— We studied 4743 patients who received heparin during PVIs in a regional, multicenter registry. From those, 1246 had recorded peak procedural ACT with the same point-of-care device. Periprocedural and in-hospital outcomes were compared between patients who received a total heparin dose &lt;60 U/kg (n=2161) and ≥60 U/kg (n=2582). Similarly, outcomes were evaluated between groups with a peak procedural ACT &lt;250 seconds (n=855) and ≥250 seconds (n=391). Technical and procedural success as well as intraprocedural thrombotic events did not differ between groups. Patients with heparin dose ≥60 U/kg had a higher rate of postprocedural hemoglobin drop ≥3 g/dL (7.09% versus 5.09%, respectively, P =0.004) and a higher transfusion rate compared with those with heparin dose &lt;60 U/kg (4.92% versus 3.15%, respectively, P =0.002). In multivariate analysis, independent predictors of bleeding requiring transfusion were total heparin dose ≥60 U/kg, ACT ≥250 seconds, female sex, age ≥70 years, prior anemia, prior heart failure, low creatinine clearance, hybrid vascular surgery, rest pain, and below-knee intervention. In propensity-matched, risk-adjusted models and after hierarchical modeling, total heparin dose ≥60 U/kg and ACT ≥250 seconds remained strong predictors of post-PVI drop in hemoglobin ≥3 g/dL or transfusion. Conclusions— During PVI, higher total heparin dose (≥60 U/kg) and peak ACT ≥250 seconds were predictors of postprocedural transfusion. The high technical and procedural success in all groups suggests that use of weight-based heparin dosing with a target ACT &lt;250 seconds in PVI may minimize the bleeding risk without compromising procedural success or increasing thromboembolic complications.

Experimental study of angiography using vascular interventional robot

To assess the feasibility and safety of vascular interventional surgery by using vascular interventional robot system (VIRS). VIRS included image navigation systems and body propulsion systems, and adopted a master-slave structure. The surgeon sat at the master site, sending controlling instructions to the robot fixed at the slave site, and then the robot translated these instructions into catheter motion. A 3D vascular model was reconstructed so that the surgeon can perform surgical planning easily. In glass model and animal experiments, the surgeon remotely controlled VIRS, which inserted a catheter into predefined targets, and the catheter positioning error and robotic surgery time were measured. The robot was initially tested on a glass vascular model. Under robotic manipulation, the catheter could enter an arbitrary branch of the vascular model. The catheter positioning error was less than 1 mm. Then robotic interventional surgery was performed successfully in ten adult dogs. The renal artery and the vertebral artery angiography carried out smoothly without complication. Experiment took 35 minutes, and the time what staff exposed to the digital subtraction angiography (DSA) machine was 0 minute. Vascular interventional surgical robot system is safe and feasible, and can achieve the catheter remote operation, meet the requirements of angiography basically.

Vascular deformation for vascular interventional surgery simulation

Obtaining the expertise to perform minimally vascular interventional surgery (VIS) requires thorough training. Previous VIS simulators have generally assumed that blood vessels are rigid. However, vascular deformation occurs unavoidably in VIS. In this study, the arterial walls were analysed as soft tissue. A mass-spring model (MSM) was applied for vascular deformation simulation. To improve simulation precision, the spring coefficient was derived from a reference model, simulated with a linear finite element method (FEM), which established a link between the spring coefficient and the properties of the vascular materials. In order to evaluate the simulation results, we applied identical external forces to FEM and MSM and calculated their deformations. Additionally, based on the proposed MSM, we designed a VIS simulator to achieve renal artery intervention. Quantitative validation was performed by comparing the simulated catheter position with a reference position, as assessed by 3D rotational angiography imaging. From the simulation results, we could clearly see that MSM deformation was real-time and very close to the linear FEM reference, and MSM was successfully adopted in our renal artery intervention simulator. MSM with a spring coefficient derived from linear FEM was able to produce a realistic deformation simulation of arterial walls. This method could also be extended to model other organ deformations.

Remote‐controlled vascular interventional surgery robot

Conventional vascular interventional surgery (VIS) is manually performed under fluoroscopic guidance, requiring lead protection for the surgeons. A remote-control vascular interventional surgery robot (VISR) which can remotely, safely and precisely perform VIS would have clear advantages. Our robot adopts a master-slave structure. The surgeon sits at the master site, sending controlling instructions to the robot fixed at the slave site, then the robot translates these instructions into catheter motion. The robotic mechanism consists of a supporting manipulator and a catheter navigator; the former adjusts the robot's spatial position, while the latter controls the translation and rotation of the catheter. A 3D vascular model is reconstructed so that the surgeon can perform surgical planning easily. In addition, the tactile force between catheter tip and blood vessel is measured, which prevents the surgeon damaging delicate vessels. In glass model and animal experiments, the surgeon remotely controlled VISR, which inserted a catheter into predefined targets, and the robotic surgery time was measured. The robot was initially tested on a transparent glass vascular model. Under robotic manipulation, the catheter can enter an arbitrary branch of the vascular model and catheter motion can meet the requirements of clinical VIS. Then robotic surgery was performed successfully in an adult dog. Surgery time to access each of the five targets, viz. renal artery, left atrium, right atrium, left ventricle and right ventricle, was measured. Compared with conventional manual surgery, robotic surgery time is a little longer. The experiments show the feasibility and safety of the VISR to facilitate navigation, position precisely and control catheters to specific regions. The VISR system offers surgeon radiation safety and minimizes surgeon-based error.

Assessment of specialists in cardiovascular practice

Assessment of medical specialists was introduced to ensure patient safety and to maintain professional knowledge. Cardiovascular specialist assessment is challenging, as the ongoing development of new technologies is associated with increased requirements for up-to-date training and acquisition of new skills. The cardiovascular specialties include cardiology, vascular interventional radiology, cardiac surgery and vascular surgery. Assessment within these disciplines involves evaluation of knowledge in addition to technical and nontechnical skills, a process that is termed recertification or maintenance of certification. Increasingly, there is a demand for professional accountability through recertification because of concerns about professional negligence and increased awareness of medical errors. In this article we describe the process of recertification in different geographical regions and discuss the role of current tools used to recertify cardiovascular specialists and, in particular, how their use can contribute to the requirements of patient care.

How Optimal is the Medical Management of Patients Prior to Major Reconstructive Vascular Surgery? The Results of a Cross-sectional Study

Risk factor modification is important in patients with vascular disease. Guidelines suggest that this patient population benefits from a medical regimen of antiplatelets, statins, beta-blockers, and angiotensin-converting enzyme (ACE) inhibitors. The medical regimen of consecutive patients who presented for major vascular surgery intervention over 18 months was examined. Of the 325 patients identified, 176 (54%) were on antiplatelet treatment, 197 (61%) were on a statin, 180 (55%) on beta-blockers, and 146 (54%) on ACE inhibitors. A high-risk subset of 94 smokers with known coronary artery disease, hypertension, and hyperlipidemia or diabetes was identified. In this subset, patients were more likely to be on pharmacologic risk factor modification. Despite recommendations, the pharmacologic risk factor modification of patients prior to vascular surgery remains suboptimal. Increased awareness of the problem and active participation of the vascular specialist are essential to improve compliance with established guidelines.

Overview of the vascular interventional robot

Conventional vascular interventional surgery (VIS) is manually performed under fluoroscopic guidance, requiring lead protection for the surgeons. In order to reduce the X-ray irradiation, the robot has been introduced to VIS in this study. The purpose of this article is to provide a comprehensive summary of the vascular interventional robot (VIR). A retrospective review of the currently published literature on VIR is discussed. The overview details the key technologies of VIR. Surgeons operate the robot far away from the patient, so protecting themselves from X-ray irradiation. The robot system carries out the VIS precisely and provides three-dimensional visualization of vasculature that can be used for preoperative planning and intra-operative navigation. The use of the vascular interventional robot appears safe and feasible for vascular interventional surgery. VIR can offer radiation safety to surgeon and enhance surgical accuracy.

Mesenteric Ischemia – Outcome after Surgical Therapy in 83 Patients

Background: Intestinal ischemia is the prime vascular emergency for the visceral surgeon. However, the diagnosis of mesenteric ischemia is difficult, the surgical options are often limited and the overall outcome is generally poor. Methods: We report on a single center series of 83 patients undergoing surgery for mesenteric ischemia during a 3-year period. Risk factors, clinical presentation, type and timing of imaging studies and their implications for surgical therapy and outcome are analyzed. Results: Hypertension and diabetes were the most common risk factors (68/64% of all patients). Abdominal pain was the most general symptom upon presentation to the surgical unit (73%). Two-phase, contrast-enhanced computed tomography was applied as the standard preoperative imaging modality (correct diagnosis in 69%). Bowel resections were necessary in most patients; approaches to restore blood flow by vascular surgery interventions were applied in 17 patients (20%). The overall morbidity and mortality rate in our study cohort was expectedly high (59% 1 month mortality). Conclusion: The diagnosis and surgical treatment of mesenteric ischemia remains a major difficulty. We recommend preoperative CT analysis followed by an aggressive indication for early surgical exploration and bowel resection. An attempt of revascularization is justified for selected patients with limited macrovascular disease.

A Stepwise Approach to the Surgical Management of Severe Diabetic Foot Infections

Foot infections are common among diabetic patients with ulceration and are a major cause of hospitalization and lower extremity amputation. Aggressive and emergent surgical intervention is essential in the face of life- or limb-threatening infection to achieve limb salvage and survival. Critical limb ischemia, neuropathy, and an impaired host complicate the treatment of a severe diabetic foot infection. A severe diabetic foot infection carries a 25% risk of major amputation. For this reason, surgery should be coordinated with a well-functioning multidisciplinary team that specializes in diabetic limb preservation. Timing of surgery and strategies employed should be understood and agreed on by both the surgical and medical disciplines managing the diabetic patient with a limb-threatening infection. The overall strategy for surgically managing a severe diabetic foot infection is as follows: the first step is infection control through aggressive and extensive surgical debridement, the second step is a comprehensive vascular assessment with possible vascular surgery and/or endovascular intervention, and the final step is soft tissue and skeletal reconstruction after infection is eradicated to obtain wound closure and limb salvage. A consistent stepwise surgical approach combined with sound surgical principles is paramount for successful management of the severe diabetic foot infection. The authors discuss their stepwise surgical approach to reduce the mortality, morbidity, psychological distress, and length of hospitalization associated with life- or limb-threatening diabetic foot infections.