Learning curve analysis of thoracic endovascular aortic repair in relation to credentialing guidelines

ObjectiveRecently, practice guideline documents have recommended the completion of different levels of interventional experience and 5 or 10 thoracic endovascular aortic cases prior to surgeon credentialing. This study’s purpose was to determine whether these requirements are valid by reviewing three surgeons’ learning curves with thoracic aortic endovascular repairs.MethodsBetween 1998 and 2006, 67 patients underwent emergent or elective endovascular repair of thoracic aortic pathologies by one of three vascular surgeons with extensive experience with catheter manipulation and abdominal aortic endografts. Following standard retrospective review, each surgeon’s learning curve was analyzed using the cumulative sum failure method with a target success rate of 95% derived from the literature. The main outcome variable was primary technical success.ResultsThese 67 patients presented with several pathologies including elective (n = 31) and ruptured (n = 11) thoracic aortic aneurysms, acute dissections or aortic ulcers (n = 10), and acute blunt thoracic aortic trauma (n = 15). The mean age was 65 (range: 20 to 90) and the early (30 day) mortality rate was 19.4% in urgent cases (n = 36) and 0% in elective cases (n = 31). Paraplegia occurred in two patients (3%). Primary technical success was achieved in 62 cases (92.5%) and did not differ between surgeons (92.6%, 91.3%, 94.1%, respectively; P = .9). Each surgeon’s cases were plotted sequentially and the resulting learning curves were similar. Although acceptable outcomes were obtained throughout the study period, improved results, compared with the target success rate, were not achieved until each surgeon treated 5 to 10 patients.ConclusionThis study supports the case volume requirements of the Society for Vascular Surgery credentialing guidelines, which also requires extensive catheter and guidewire experience. With this background in catheter manipulation and endovascular abdominal aortic repair, surgeons can achieve optimal outcomes with thoracic aortic lesions following 5 to 10 cases

Simultaneous Individually Controlled Upper and Lower Body Perfusion for Valve-Sparing Root and Total Aortic Arch Replacement: A Case Study

Optimal perfusion strategies for extensive aortic resection in patients with mega-aortic syndromes include: tailored myocardial preservation, antegrade cerebral perfusion, controlled hypothermia and selective organ perfusion. Typically, the aortic arch resection and elephant trunk procedure are performed under hypothermic circulatory arrest with myocardial and cerebral protection. However, mesenteric and systemic ischemia occur during circulatory arrest and commonly rely upon deep hypothermia alone for metabolic protection. We hypothesized that simultaneously controlled mesenteric and systemic perfusion can attenuate some of the metabolic debt accrued during circulatory arrest, which may help improve perioperative outcomes. The perfusion strategy consisted of delivering a 1 to 3 liter per minute flow at 25°C to the head/upper body via right axillary graft and simultaneous perfusion to the lower body/mesenteric organs of 1 to 3 liters per minute at 30°C via a right femoral arterial graft. We describe our technique of simultaneous mesenteric, systemic, cerebral and myocardial perfusion, and protection utilized for a young male patient with Marfan’s syndrome, while undergoing a valve sparing root replacement, total arch replacement and elephant trunk reconstruction. This perfusion technique allowed us to deliver differential flow rates and temperatures to the upper and lower body (cold head/warm lower body perfusion) to minimize ischemic debt and quickly reverse metabolic derangements

Higher-risk mitral valve operations after previous sternotomy: endoscopic, minimally invasive approach improves patient outcomes

BACKGROUND: Reoperative mitral valve (MV) surgery is associated with significant morbidity and mortality; however, endoscopic minimally invasive surgical techniques may preserve the surgical benefits of conventional mitral operations while potentially reducing perioperative risk and length of stay (LOS) in hospital. METHODS: We compared the outcomes of consecutive patients who underwent reoperative MV surgery between 2000 and 2014 using a minimally invasive endoscopic approach (MINI) with those of patients who underwent a conventional sternotomy (STERN). The primary outcome was in-hospital/30-day mortality. Secondary outcomes included blood product transfusion, LOS in hospital and in the intensive care unit (ICU), and postoperative complications. RESULTS: We included 132 patients in our study: 40 (mean age 68 ± 14 yr, 70% men) underwent MINI and 92 (62 ± 13 yr, 40% men) underwent STERN. The MINI group had significantly more comorbidities than the STERN group. While there were no significant differences in complications, all point estimates suggested lower mortality and morbidity in the MINI than the STERN group (in-hospital/30-day mortality 5% v. 11%, p = 0.35; composite any of 10 complications 28% v. 41%, p = 0.13). Individual complication rates were similar between the MINI and STERN groups, except for intra-aortic balloon pump requirement (IABP; 0% v. 12%, p = 0.034). MINI significantly reduced the need for any blood transfusion (68% v. 84%, p = 0.036) or packed red blood cells (63% v. 79%, p = 0.042), fresh frozen plasma (35% v. 59%, p = 0.012) and platelets (20% v. 40%, p = 0.024). It also significantly reduced median hospital LOS (8 v. 12 d, p = 0.014). An exploratory propensity score analysis similarly demonstrated a significantly reduced need for IABP (p < 0.001) and a shorter mean LOS in the ICU (p = 0.046) and in hospital (p = 0.047) in the MINI group. CONCLUSION: A MINI approach for reoperative MV surgery reduces blood product utilization and hospital LOS. Possible clinically relevant differences in perioperative complications require assessment in randomized clinical trials

The role of visual and direct force feedback in robotics-assisted mitral valve annuloplasty

Copyright © 2016 John Wiley & Sons, Ltd. Background: The objective of this work was to determine the effect of both direct force feedback and visual force feedback on the amount of force applied to mitral valve tissue during ex vivo robotics-assisted mitral valve annuloplasty. Methods: A force feedback-enabled master–slave surgical system was developed to provide both visual and direct force feedback during robotics-assisted cardiac surgery. This system measured the amount of force applied by novice and expert surgeons to cardiac tissue during ex vivo mitral valve annuloplasty repair. Results: The addition of visual (2.16 ± 1.67), direct (1.62 ± 0.86), or both visual and direct force feedback (2.15 ± 1.08) resulted in lower mean maximum force applied to mitral valve tissue while suturing compared with no force feedback (3.34 ± 1.93 N; P \u3c 0.05). Conclusions: To achieve better control of interaction forces on cardiac tissue during robotics-assisted mitral valve annuloplasty suturing, force feedback may be required

Augmented Reality System for Ultrasound Guidance of Transcatheter Aortic Valve Implantation

Copyright © 2016 by the International Society for Minimally Invasive Cardiothoracic Surgery. Objective: Transcatheter aortic valve implantation (TAVI) relies on fluoroscopy and nephrotoxic contrast medium for valve deployment. We propose an alternative guidance system using augmented reality (AR) and transesophageal echocardiography (TEE) to guide TAVI deployment. The goals of this study were to determine how consistently the aortic valve annulus is defined from TEE using different aortic valve landmarks and to compare AR guidance with fluoroscopic guidance of TAVI deployment in an aortic root model. Methods: Magnetic tracking sensors were integrated into the TAVI catheter and TEE probe, allowing these tools to be displayed in an AR environment. Variability in identifying aortic valve commissures and cuspal nadirs was assessed using TEE aortic root images. To compare AR guidance of TAVI deployment with fluoroscopic guidance, a TAVI stent was deployed 10 times in the aortic root model using each of the two guidance systems. Results: Commissures and nadirs were both investigated as features for defining the valve annulus in the AR guidance system. The commissures were identified more consistently than the nadirs, with intraobserver variability of 2.2 and 3.8 mm, respectively, and interobserver variability of 3.3 and 4.7 mm, respectively. The precision of TAVI deployment using fluoroscopic guidance was 3.4 mm, whereas the precision of AR guidance was 2.9 mm, and its overall accuracy was 3.4 mm. This indicates that both have similar performance. Conclusions: Aortic valve commissures can be identified more reliably than cuspal nadirs from TEE. The AR guidance system achieved similar deployment accuracy to that of fluoroscopy while eliminating the use and consequences of nephrotoxic contrast and radiation