Cannula Angle Research Articles

Preoperative anatomical landmarks and longitudinal HeartMate 3 pump position in X-rays: Relevance for adverse events.

Left ventricular assist device (LVAD) malposition has been linked to hemocompatibility-related adverse events (HRAEs). This study aimed to identify preoperative anatomical landmarks and postoperative pump position, associated with HRAEs during LVAD support. Pre- and postoperative chest X-ray measures (≤14 days pre-implantation, first postoperative standing, 6, 12, 18, and 24 months post-implantation) were analyzed for their association with HRAEs over 24 months in 33 HeartMate 3 (HM3) patients (15.2% female, age 66 (9.5) years). HM3 patients with any HRAE showed significantly lower preoperative distances between left ventricle and thoracic outline (dLVT) (25.3 ± 10.2 mm vs. 40.3 ± 15.5 mm, p = 0.004). A ROC-derived cutoff dLVT ≤ 29.2 mm provided 85.7% sensitivity and 72.2% specificity predicting any HRAE during HM3 support (76.2% (>29.2 mm) vs. 16.7% (≤29.2 mm) freedom from HRAE, p < 0.001) and significant differences in cardiothoracic ratio (0.58 ± 0.04 vs. 0.62 ± 0.04, p = 0.045). Postoperative X-rays indicated lower pump depths in patients with ischemic strokes (9.1 ± 16.2 mm vs. 38.0 ± 18.5 mm, p = 0.007), reduced freedom from any neurological event (pump depth ≤ 28.7 mm: 45.5% vs. 94.1%, p = 0.004), and a significant correlation between pump depth and inflow cannula angle (r = 0.66, p < 0.001). Longitudinal changes were observed in heart-pump width (F(4,60) = 5.61, p < 0.001). Preoperative X-ray markers are associated with postoperative HRAE occurrence. Applying this knowledge in clinical practice may enhance risk stratification, guide therapy optimization, and improve HM3 recipient management.

Safety and Effectiveness of a Novel Tips Access Set with Steerable Cannula in a Swine Model

PurposeThis study aimed to assess the safety, effectiveness, and feasibility of the Liverty™ transjugular intrahepatic portosystemic shunt (TIPS) access set, which has an ergonomic handle that allows for in situ cannula tip deflection and a distal steerable cannula angle, versus the COOK® Rosch-Uchida Transjugular Liver Access Set (RUPS-100) in healthy pigs.MethodsTwelve pigs randomly underwent TIPS with the Liverty™ set or the RUPS-100 set. Three interventionalists performed 4 TIPS procedures, 2 with each set. The primary outcome was procedural success, defined as successful establishment of the intrahepatic portosystemic shunt and stent placement.ResultsThe shunt was successfully established in 11 pigs. The procedural success was achieved in all 6 pigs in the Liverty™ group and 5 out of 6 pigs for the RUPS-100 group (Fisher exact test, P > 0.999). The mean duration of puncture was shorter in the Liverty™ group versus the RUPS-100 group (12.3 ± 4.5 min vs. 16.2 ± 8.5 min), but without significant statistical difference (two sample t test, P = 0.359). The cannula angle was adjusted 69% of passes in the Liverty™ group, which was significantly higher than that in the RUPS-100 group (12%, P = 0.004). Overall, the TIPS procedural performance was comparable between the groups. Both sets were safe. No intraabdominal hemorrhage, vascular injuries, tissue or organ injuries, porto-biliary fistula, biliary peritonitis, and infection or abscess occurred in either group.ConclusionThe Liverty™ set is safe and has similar procedural metrics to the COOK® RUPS-100 set. It allows in situ adjustment of the angle of the stiffening cannula without increasing procedure time and lessens the occurrences of periprocedural complications.Graphical

Comparing left ventricular assist device inflow cannula angle between median sternotomy and thoracotomy using 3D reconstructions.

Left ventricular assist device (LVAD) implantation via thoracotomy has many potential advantages compared to conventional sternotomy, including improved inflow cannula (IFC) positioning. We compared the difference in IFC angles, postoperative, and long-term outcomes for patients with LVADs implanted via thoracotomy and sternotomy. A single-center, retrospective analysis of 14 patients who underwent thoracotomy implantation was performed and matched with 28 patients who underwent sternotomy LVAD implantations for a total of 42 patients. Inclusion required a minimum LVAD support duration of 30 days and excluded concomitant procedures. A postoperative CT-chest was used to measure the angle the between the IFC and mitral valve in two-dimensions and results were compared with three-dimensional reconstruction using the same CT chest. Outcome data were extracted from medical records. There was no significant difference in gender, INTERMACS score, BMI, or age between the two groups. Median cardiopulmonary bypass time was longer in the thoracotomy group compared to the sternotomy group, 107min (86-122) versus 76min (56-93), p < 0.01. 3D reconstructions revealed less deviation of the IFC away from the mitral valve in devices implanted via thoracotomy compared to sternotomy, median (IQR) angle 16.3° (13.9°-21.0°) versus 23.2° (17.9°-26.4°), p < 0.01. Rates of pump thrombosis, stroke, and gastrointestinal bleeding were not significantly different. Devices implanted via thoracotomy demonstrated less deviation away from mitral valve. However, there was no difference in morbidity between the two approaches. 3D reconstruction of the heart is an innovative technique to measure angulation and is clinically advantageous when compared to 2D imaging.

Association of Outflow Cannula Angulation with Adverse Neurological Events in Patients with CF-LVAD

<h3>Purpose</h3> Adverse neurological outcomes are the Achilles heel of the current day LVAD technology and are associated with worse survival. Our previous data suggests that outflow cannula (OFC) angles measured using cardiac CT may correlate with stroke in continuous-flow HeartMate II patients. Therefore, the aim of our study was to assess the relationship of inflow cannula (IFC) and outflow cannula (OFC) position with neurological outcomes centrifugal flow pumps (HM3 and HVAD). <h3>Methods</h3> 108 patients underwent LVAD implantation between 2015 and 2019 at our institution. Of these, 68 patients underwent cardiac CT, and 6 were excluded due to poor image quality. Of these patients, a total of 32 neurological events (NE) occurred in 20 patients. These cases were compared to patients with CT data who did not have NEs. 2D angle measurements were performed on positions of OFC relative to the ascending aorta and IFC relative to the mitral valve. Further we used a novel point-based 3D measurement system to determine the angles in an x-y-z plane. Baseline demographic data and outcome data were collected for all patients. Optimal cut-point of the OFC angle was determined using ROC curve analysis. <h3>Results</h3> Of the 62 patients recruited for this study, 65% had HM3 and 35% had HVAD. The median OFC angle on 2D in patients with NE was 59.8 degrees relative to the aorta, compared with a median angle of 51.7 degrees in patients without NE (p=0.02). Similarly on 3D angle measurements, a median OFC angle of 86.7 degree was observed in patients with NE, compared to a median angle of 77.4 degrees in patients without NE (p=0.01). IFC angle was not associated with an increased risk of NE. The ROC curve analysis showed optimal OFC angle was < 53 degrees in 2D measurements, with sensitivity of 79% and specificity of 61% at predicting NEs. In 3D measurements the optimal OFC angle was less than < 83 degrees with a sensitivity of 79% and a specificity of 61% at predicting NEs. <h3>Conclusion</h3> Optimal angulation of the outflow cannula in LVAD patients can lead to decreased risk for HRAE. Using cardiac CT chest imaging for 2D and 3D measurements, an optimal outflow cannula angulation of < 53 degrees and < 83 degrees, respectively, should be preferred to minimize the risk for HRAE in patients with centrifugal flow LVAD support.

Mechanical support for the failing single ventricle after Fontan

Mechanical support for the failing single ventricle after Fontan

Abstract 13317: Optimization of Left Ventricular Assist Device Therapy: A Combined in vitro and in silico Strategy to Reduce Thromboembolic Adverse Events via Evidence-Based Surgical Configuration and Medical Management

Introduction: Left Ventricular Assist Devices are growing in frequency and importance in the treatment of medical-refractory heart failure. The incidence of thromboembolic events is a principal cause of mortality and morbidity for these patients, despite third generation pumps greatly reducing in-pump thrombosis. Hypothesis: To understand this problem, we hypothesize that LVAD-induced hemodynamics precondition platelets to activate and aggregate, leading to incipient thrombus formation which may propagate throughout the circulation, explaining the high incidence of thromboembolic events in the absence of in-pump thrombosis. Methods: A combined computational and in vitro modeling approach is used to simulate blood flow in the left ventricle, LVAD inflow cannula, outflow graft and aortic arch, with the goal of understanding the role of LVAD therapy in hemodynamics. Results: A systematic optimization of surgical parameters (inflow cannula angle, inflow cannula insertion depth, outflow graft anastomosis angle, outflow graft diameter) and medical management (LVAD speed, blood pressure, aortic valve opening frequency) based on Lagrangian metrics confirmed that the thrombogenicity of LVAD therapy can be potentially be significantly reduced. These metrics allow for quantitative comparisons of device management. Guidelines of optimum ranges of therapy configurations, and definition of “high risk” surgical configurations to avoid have been proposed. Conclusions: Reducing thrombogenicity and improving hemocompatibility is the next frontier in durable LVAD therapy for advanced heart failure. Risk-benefit analysis of many surgical configurations and medical management strategies can be quantitatively analyzed. Systematic analysis can serve as the rationale for future clinical trials that will optimize patient outcomes and reduce complications.

Emergency Front-of-Neck Airway Rescue Via the Cricothyroid Membrane: A High-Resolution Computed Tomography Study of Airway Anatomy in Adults.

Emergency front-of-neck airway rescue is recommended in a can't intubate, can't oxygenate clinical scenario. Cannula cricothyroidotomy has been reported as having a high failure rate. Our primary aim was to estimate the angle of the trachea in relation to the horizontal axis in a simulated emergency front-of-neck airway rescue position. Our secondary aims were to estimate the optimal cannula angle of approach and evaluate the anatomical relationship of the cricothyroid membrane (CTM) to adjacent structures. We also assessed whether the CTM lies above or below the neck midpoint, a point equidistant from the suprasternal notch (SSN), and the chin surface landmarks. All measurements were compared between the male and female subjects. Subjects having elective computed tomography of their thorax were consented to have extension of the computed tomography to include their neck. A preliminary radiation dose and risk assessment deemed the additional radiation to be of very low risk (level IIa). Subjects were positioned supinely on the computed tomography table. Standard neck extension was achieved by placing a pillow under the scapulae and a rolled towel under the neck to simulate emergency front-of-neck airway rescue positioning. Fifty-two subjects were included in this study: 31 men and 21 women. The mean angle of the trachea in relation to the horizontal axis was 25.5° (95% confidence interval [CI], 21.8-29.1) in men and 14.0° (95% CI, 11.5-16.5) in women. The mean minimum angles required for hypothetical cannula cricothyroidotomy for men and women were 55.2° (95% CI, 51.8-58.7) and 50.5° (95% CI, 45.4-55.6), respectively. The CTM was located lower in the neck in men compared to women. The CTM was located below the neck midpoint in 30 of 30 (100%) male subjects and 11 of 20 (55%) female subjects (P < .001). The trachea angulates posteriorly in a simulated emergency front-of-neck airway rescue position in supine subjects and to a greater degree in men compared to women (P < .001). The minimum angle required for hypothetical cannula cricothyroidotomy was >45° in the majority (75%) of subjects studied. A steeper cannula angle of approach may be more reliable and warrants further clinical study. If airway anatomy is indistinct and performing a vertical scalpel cricothyroidotomy, consideration should be given to performing this incision lower in the neck in men compared to women.

Left ventricular assist device implantation by bi-thoracotomy technique: A single-center perspective.

Left ventricular assist devices (LVAD) are standardly implanted via full sternotomy. Nonsternotomy approaches are gaining popularity, but potential benefits of this approach have not been well-studied. We hypothesized that LVAD implantation by bi-thoracotomy (BT) would demonstrate smaller and more consistent inflow cannula angles leading to improved postoperative outcomes compared to sternotomy. Charts of patients who underwent LVAD implantation between June 2018 and June 2020 at a single academic institution were retrospectively reviewed. Patient demographics, surgical approach (sternotomy vs. BT), laboratory values, and postoperative course were compared. The inflow cannula angle was measured on the first chest radiograph available postoperatively. Of 40 patients studied, BT approach was used in 17 (42.5%). Mean inflow cannula angles were smaller in BT patients (23.0 vs. 37.1 degrees, p = .018) and had a smaller standard deviation (13.8 vs. 20.3). Excluding patients who went on to receive a heart transplant or died in the same hospitalization, there was no difference in median length of hospital stay after surgery (16.0 vs. 17.5 days, p = .768). However, BT patients required fewer days of postoperative inotrope support (4.0 vs. 7.0 days, p = .012). Our data suggest inflow cannula angles are smaller and more consistent with the BT approach, which leads to a shorter duration of postoperative inotropic support. This finding may suggest improved right heart function following LVAD implant via BT approach. Further study is warranted to determine additional benefits of the BT approach.

Comparing HVAD Inflow Cannula Angle between Median Sternotomy and Thoracotomy

<h3>Purpose</h3> Left ventricular assist device (VAD) implantation via thoracotomy is a safe operation with potential advantages compared to conventional sternotomy. One proposed advantage is improved inflow cannula (IFC) positioning due to better visualisation. We investigated the difference in IFC angles for patients with HVADs implanted via these techniques and compared post-operative as well as long term outcomes. <h3>Methods</h3> 42 patients were retrospectively selected from our VAD database. 28 in the sternotomy group and 14 in the thoracotomy group. We included all thoracotomy implants performed at our centre and consecutive sternotomy implants from 2015-2019. Inclusion required a minimum support time of 30 days. Patients with concomitant procedures were excluded. The first post-operative CT chest scan was used to measure the angle between the IFC and mitral valve in axial and coronal planes. <h3>Results</h3> There was no significant difference in gender, INTERMACS score, BMI or age between the two groups. Median support time was not significantly different between the thoracotomy and sternotomy groups (328 vs 360 days, p=0.9). Median cardiopulmonary bypass (CPB) time was higher in the thoracotomy group (104 vs 78 minutes, p<0.01). Median ICU length of stay for the thoracotomy group was 5 days compared to 8 days in the sternotomy group, p=0.08. There was no significant difference in median IFC angle on the axial plane between the thoracotomy group and the sternotomy group (9 degrees v 10 degrees, p=0.3). Similarly, there was no difference in the coronal plane (9 degrees vs 12 degrees, p=0.9). Rates of pump thrombosis, stroke and GI bleeding were not significantly different between the two groups. <h3>Conclusion</h3> In our sample size of 42 patients, the thoracotomy group had a slightly longer CPB time, however, there was no difference in IFC angle, pump thrombosis, GI bleeding, stroke or ICU length of stay. In saying this, there may be other benefits to the thoracotomy approach such as facilitating easier sternal entry upon transplantation.

Intraoperative Use of Computer-Aided 3D Printed Exoskeleton Supporting Left Ventricular Assist Device Implantation

We aimed to establish a 3D guiding model which can provide the proper position of the LVAD during surgical implantation with the prediction of the changes of fluid dynamical pattern inside the left ventricle. We want to describe a simple, reproducible technique for implanting LVAD to ensure proper positioning, which improve results in the postoperative period. A personalized 3D heart model was created for left ventricular assist device implantation, using CT angiography scans. This step ensures the accurate anatomical position of the inflow cannula (IC). The next step is the flow simulation where the fine adjustment of IC placement was predicted, using computational fluid dynamical modeling. In silico 50 different inflow cannula angles were adjusted and simulated the changes of the left ventricle flow pattern in every angle. The angle corresponding to the best intraventricular flow patter was selected from the 50 simulation results. When we know the proper anatomical position and angle of the IC, a personalized 3D exoskeleton was planned on the virtual surface of the patient's heart. Consequently, the simulation coordinates were transferred to 3D printed surgical guiding exoskeleton. In operation room, the exoskeleton was placed on the surface of the heart to guide the coring procedure during LVAD implantation. The coring knife was slipped in the coring guiding tube. After the coring procedure, the LVAD was implanted routinely. Since 2018 twelve implantations were performed utilizing our patent with no incidences of inflow cannula misplacement, thrombosis, stroke and right heart failure due to inaccurate IC position. Comparing the planned and the actual postoperative angles of the implanted devices inflow cannula, a significant difference was not shown. It proves that the surgical implementation of the calculation was excellent during the operation, using the 3D printed surgical guiding exoskeleton. With our method, the standardization of the apex coring and IC positionoing during LVAD implantation was achievable, and the surgical steps were predictable. Therefore, a new decision-making support system was established in cardiac surgery, improving implantation success. The described technique is simple, easily reproducible, and accurate. The exoskeleton is patent filed, the pending patent number: P1800379.

Association of LVAD Cannula Position with Stroke Risk

Stroke remains a major cause of morbidity and mortality in LVAD patients, with incidence upto to 22%. We hypothesized that certain LVAD cannula positions are associated with unfavourable flow patterns resulting in altered thrombogenicity, and therefore higher stroke risk. We conducted a retrospective review of patients that underwent LVAD implantation at our institution from 2011 to 2016. All patients who underwent cardiac CT scan, were included. Patients with non-contrast CT scans, and poor quality imaging data were excluded. We studied imaging data from three modalities: X-ray, Echocardiography and cardiac CT. The primary outcome was defined as stroke within one year of LVAD implantation. A total of 78 patients were included in the study. The predominant device was HeartMate II (94.8%), there were three patients with HVAD and one patient with HeartMate III. Of these, 12 patients had stroke within one year of LVAD implantation: 10 were ischemic and 2 were hemorrhagic. Mean time to stroke was 108 days. There were no significant differences between the two groups with regard to X-ray or Echocardiographic variables. The mean outflow cannula angle in the stroke group was 61.19 degrees, whereas that in the non-stroke cohort was 45.92 degrees. The mean diameter of outflow cannula anastomosis in the stroke group was 1.52 cm whereas that in the non-stroke group was 1.34 cm. Our study was the first to show that LVAD outflow cannula angle and diameter of anastomosis are significantly associated with stroke risk. Therefore, optimization of surgical technique/ engineering methods may help mitigate stroke risk in LVAD patients.

Sternal-Sparing Approach for LVAD Implantation Allows for a More Consistent Inflow Cannula Angle

Prior study has suggested an association between angulation of the inflow cannula and outcomes following left ventricular assist device (LVAD) implantation. A potential benefit of the sternal-sparing LVAD implantation technique is superior visualization of the apex in its natural anatomic position. Our hypothesis was the sternal-sparing technique would result in more consistent angle of LVAD implantation. This single-center, retrospective review included consecutive patients implanted from September 2015 through September 2019. Patients were stratified via surgical technique: sternal-sparing or median sternotomy. The coronal angle of the inflow cannula relative to the horizontal line was measured on the first available postoperative anterior-posterior chest radiograph (Figure 1). All measurements were calculated by trained radiologists. A randomly selected subgroup of patients was repeated by multiple readers to assess interrater reliability. Of the 161 patients included in the study, 102 (63%) were implanted via the sternal-sparing approach. Preoperative patient characteristics were similar between cohorts. The inflow cannula angle was significantly different between cohorts (Figure 1, p=0.020). The sternal-sparing cohort had a more consistent angle (median [IQR], 18 [6-29] degrees) compared to the sternotomy patients (25 [10-42] degrees, p=0.020). Significantly more sternal-sparing patients had an angle ≤65 degrees (100% vs 93%, p=0.017), which has previously been associated with improved patient outcomes with a different model pump. Our data suggests the angle of the inflow cannula after LVAD implantation is more consistently reproduced when utilizing the sternal-sparing approach compared to median sternotomy. Further research is needed to examine the relationship between inflow cannula angle and patient outcomes to determine the ideal inflow cannula angle for the fully magnetically levitated pump.

HeartWare Ventricular Assist Device Cannula Position and Hemocompatibility-Related Adverse Events

HeartWare ventricular assist device (HVAD) cannula position is associated with hemodynamics and heart failure readmissions. However, its impact on hemocompatibility-related adverse events (HRAEs) remains uncertain. HVAD patients were followed for 1 year afterindex hospitalization, when cannula coronal angle was quantified from chest x-ray film. Invasive right heart catheterization and transthoracic echocardiography were performed. One-year occurrences of each HRAE were compared between those with and without a cannula coronal angle of greater than 65 degrees. Among 63 HVAD patients (median age 60 years, 63% male), 10 (16%) had a cannula coronal angle greater than 65 degrees. The wide-angle group had elevated intracardiac pressures and lower pulmonary artery pulsatility index (P < .05). They also had reduced right ventricular function by echocardiography. Freedom from HRAEs tended to be lower in the wide-angle group (24% vs 62%; P= .11). The rate of gastrointestinal bleeding was significantly higher in the greater than 65 degrees group (0.90 events/year vs 0.40 events/year; P= .013). The rates of stroke and pump thrombosis were statistically comparable irrespective of cannula angle (P > .05). HVAD cannula coronal angle was associated with reduced right ventricular function and HRAEs. Prospective studies evaluating surgical techniques to ensure optimal device positioning and its effects on HRAEs are warranted.

The Importance of Left Ventricular Assist Device Inflow Cannula Angle and the Relationship to Cardiac and Anatomical Geometry.

The Importance of Left Ventricular Assist Device Inflow Cannula Angle and the Relationship to Cardiac and Anatomical Geometry.

Association of Inflow Cannula Position with Left Ventricular Unloading and Clinical Outcomes in Patients with HeartMate II Left Ventricular Assist Device.

The relationship between the HeartMate II left ventricular assist device (LVAD) position and pump thrombosis has been reported. However, further clinical implications of device position are unknown. This study aimed to investigate optimal device position for better left ventricular (LV) unloading and patient prognosis. Patients undergoing a ramp test with right heart catheterization after HeartMate II LVAD implantation were enrolled to this study. Device position was quantified from the chest X-ray obtained at the time of the ramp test: (1) inflow cannula angle relative to horizontal line, (2) pump angle relative to spine, (3) pump depth, (4) angle between inflow cannula and pump, and (5) angle between pump and outflow graft. LV unloading was assessed by pulmonary capillary wedge pressure at set LVAD speed. Fifty-four patients (60 years old and 34 male [63%]) were enrolled. Nobody experienced device malfunction during the study period. Increased LV unloading (i.e., lower pulmonary capillary wedge pressure) was associated with a narrower inflow cannula angle relative to horizontal line. Inflow cannula angle <75° was associated with higher 1 year heart failure readmission-free survival rate (p < 0.05, hazards ratio 7.56 [95% confidence interval 2.32-24.7]). In conclusion, HeartMate II LVAD inflow cannula position was associated with LV unloading and patient prognosis. Prospective studies to ensure optimal device positioning and target better clinical outcomes are warranted.

The Implication of HeartWare HVAD Inflow Cannula Angle on Stroke and Thrombus Rate

Purpose Stroke and ventricular assist device (VAD) pump thrombus are serious complications that have previously been thought to be related to surgical placement - namely VAD inflow cannula angle. Our aim with this study was to better elucidate the impact of post-operative HeartWare HVAD (left VAD) cannula inflow angle on stroke and thrombus rate within a single centre in Sydney, Australia. Methods Data were extracted retrospectively for all patients who underwent Heartware HVAD implantation from 2007-2017 with accessible on-site CT imaging. BiVAD patients were excluded. Angulation data was available for 95 patients. Post-implant inflow angle was measured between the middle of the inflow cannula relative to the middle of the sternum . All measurements were carried out in the axial plane on CT imaging. Data on Free Haemoglobin level was extracted at 3 intervals (3, 6, and 12-months post VAD implantation). Statistical analysis was carried out using IBM SPSS v25. Results Mean post-operative inflow cannula angle was 89 +/- 27 degrees vs 91 +/- 22 degrees for the non-stroke and stroke groups respectively, p=NS. Similarly, there was no difference in mean post-operative inflow cannula angle between those that formed pump thrombus (89 +/- 28 degrees) and those that did not (91 +/- 19 degrees), p=NS. Average 12-month post-implant Free Haemoglobin was higher in the group with pump thrombus than the group that did not form thrombus (9.1 +/- 9 vs 5.3 +/- 9), p=0.012. Conclusion There was no association between HVAD cannula inflow position and incidence of stroke or thrombus rates in this population. The previous finding of an interaction between inflow cannula angulation and pump thrombosis may be device specific.

HVAD Cannula Positioning is Associated with Higher GI Bleed Rates

Purpose HVAD cannula positioning is associated with hemodynamics and heart failure readmissions. However, its impact on hemocompatibility-related adverse events (HRAEs) in general, and GI bleeding in particular, remains uncertain. This study assessed the impact of HVAD cannula positioning on HRAEs. Methods HVAD patients were followed for one year following the index hospitalization discharge, when the cannula coronal angle was quantified from chest X-ray (Figure 1A). One-year freedom from any HRAEs and event rates of each HRAE were compared between those with and without cannula coronal angle >65 degrees. Results Among 46 HVAD patients (median age 61 years, 76% male), 9 patients (20%) had cannula coronal angle >65 degrees. The rate of GI bleeding was significantly higher in the angle >65 group (1.03 vs. 0.19 events/year, p = 0.014). Rates of stroke and pump thrombosis were comparable irrespective of the cannula angle (p >0.05 for all; Figure 1B). One-year freedom from any HRAEs was numerically lower in the angle >65 group compared with the angle ≤65 group (22% vs. 63%, p = 0.062; Figure 1C). Conclusion HVAD cannula coronal angle is associated with increased GI bleed. Prospective studies evaluating surgical techniques to ensure optimal device positioning and its effects on HRAEs are warranted.

Pump Position Impacts HeartMate II Left Ventricular Assist Device Thrombosis.

The PREVENtion of HeartMate II pump Thrombosis through clinical management (PREVENT) study was a multicenter, prospective investigation to evaluate the rate of pump thrombosis (PT) with adoption of a uniform set of surgical and medical practices for left ventricular assist device implantation. We sought to quantify pump position at baseline and retrospectively define a pump position associated with poor clinical outcomes. Chest x-rays at baseline were prospectively obtained per protocol. Pump pocket depth, inflow cannula (IC) angle relative to the pump, and IC angle relative to the vertical were measured. Pumps falling in the tail-ends of the IC angle and pump pocket depth distributions were categorized as having an extreme pump position within the PREVENT study. Patients with extreme pump position had a significantly higher risk of confirmed and suspected PT, hemolysis, and elevated lactate dehydrogenase. In a multivariable analysis of survival free of confirmed PT, extreme pump position was an independent risk factor (hazard ratio = 3.6; 95% confidence interval = 1.5-8.9; p = 0.006) when adjusting for differences in pump speed and anticoagulation level. Our analysis shows that HeartMate II pump position at implant can significantly impact event-free survival and the incidence of adverse events at 6 months.

The Effect of Inflow Cannula Angle on the Intraventricular Flow Field of the Left Ventricular Assist Device-Assisted Heart: An In Vitro Flow Visualization Study.

Previous studies have identified left ventricular assist device (LVAD) inflow cannula (IC) malposition as a significant risk for pump thrombosis. Thrombus development is a consequence of altered flow dynamics, which can produce areas of flow stasis or high shear that promote coagulation. The goal of this study was to measure the effect of IC orientation on the left ventricle (LV) flow field using a mock circulatory loop, and identify flow-based indices that are sensitive measures of cannula malposition. Experimental studies were performed with a customized silicone model of the dilated LV and the EVAHEART Centrifugal LVAS (Evaheart, Inc.; Houston TX). The velocity field of the LV midplane was measured for a transparent IC oriented parallel to and rotated 15° toward the septum under matched hemodynamic conditions. Vortex structures were analyzed and localized stasis calculated within the IC and combined with a map of normalized pulsatile velocity. The velocity fields revealed increased apical stasis and lower pulsatility with a small angulation of the IC. A significant change in vortex dynamics with the angled IC was observed, doubling the size of the counterclockwise (CCW) vortex while reducing the kinetic energy provided by LVAD support. A significant decrease in average and systolic velocities within the IC was found with cannula angulation, suggesting an increased resistance that affects primarily systolic flow and is worsened with increased LVAD support. These common echocardiographic indices offer the opportunity for immediate clinical application during ramp study assessment. Optimized IC positioning may be determined preoperatively using imaging techniques to develop patient-specific surgical recommendations.

Telecardiographic measurements for device migration: A useful tool for follow-up.

OBJECTIVE:Pump thrombosis in left ventricular assist device (LVAD) patients is an important cause of mortality and morbidity. Inflow cannula migration is a predisposing factor for pump thrombosis. Telecardiographic measurements can be used to follow up apical cannula deviation. In this study, we aimed to evaluate the migration of the inflow cannulas in patients with LVADs using angle measurements on telecardiogramsMETHODS:Twenty-three patients who were implanted left ventricular assist devices in our clinic between February 2013 and April 2016 were included in our study. During the first year of follow-up, changes in angle measurements on postoperative 1st, 3rd, 6th, and 12th month telecardiograms were compared against the incidence of device thrombus and serum Lactate Dehydrogenase (LDH) levels.RESULTS:Patients who were diagnosed with device thrombosis had more change in inflow cannula angles than patients without device thrombus (p<0.05 at 6th and 12th months). Patients with higher LDH values had more parallel angular changes at all intervals, and the change in angle was statistically significant at 3rd, 6th and 12th months (p<0.05).CONCLUSION:This study shows that it is possible to track the migration of inflow cannulas in patients with left ventricular heart failure using telecardiograms. The correlation between angle change and LDH levels and embolic events may suggest that telecardiographic follow up of angles may be a useful tool for ventricular assist devices teams for early detection of thrombus.