Maria Elizabeth Currie, MD, PhD

All Publications

• Survival, Function, and Immune Profiling after Beating Heart Transplantation. The Journal of thoracic and cardiovascular surgery Krishnan, A., Elde, S., Ruaengsri, C., Guenthart, B. A., Zhu, Y., Fawad, M., Lee, A., Currie, M., Ma, M. R., Hiesinger, W., Shudo, Y., MacArthur, J. W., Woo, Y. J. 2024

  Abstract

  Ex-vivo normothermic perfusion of cardiac allografts has expanded the donor pool. Utilizing a beating heart implantation method avoids the second cardioplegic arrest and subsequent ischemia reperfusion injury typically associated with ex-vivo heart perfusion. We sought to describe our institutional experience with beating heart transplantation.This was a single-institution retrospective study of adult patients who underwent heart transplantation utilizing ex-vivo heart perfusion (EVHP) and a beating heart implantation technique between October 2022 and March 2024. Primary outcomes of interest included survival, initiation of mechanical circulatory support, and rejection. A sub-analysis of our institutional series of non-beating DCD heart transplantation was also performed.Twenty-four patients underwent isolated heart transplantation with the use of ex-vivo heart perfusion and beating heart implantation between October 2022 and March 2024; 21 (87.5%) received hearts from DCD donors, and 3 (12.5%) patients received hearts from DBD donors. Median follow-up was 192 days (interquartile range of 124-253.5 days), and 23 out of 24 patients (95.8%) were alive at last follow up. No patients required initiation of mechanical circulatory support. The majority of patients had pathological grade 0 rejection at the time of biopsy (n=16, 66.7%), and the median cell-free DNA percent was 0.04% (interquartile range 0.04-0.09). The rate of mechanical circulatory support initiation in the 22-patient non-beating DCD heart transplant cohort was significantly higher at 36.4% (p<0.005).A beating heart implantation technique can be used on DCD and DBD hearts on EVHP and is associated with excellent survival and low levels of rejection.

  View details for DOI 10.1016/j.jtcvs.2024.07.058

  View details for PubMedID 39111693

• Induction Therapy Confers Survival Advantage in Mechanically Supported Patients Regardless of Peak CPRA in Heart Transplantation Bahatyrevich, N., Dale, R., Leipzig, M., Pines, K., Jimenez, S., Currie, M. ELSEVIER SCIENCE INC. 2024: S148

  View details for Web of Science ID 001281353100282

• Nonlinear Effect of Body Mass Index on Postoperative Survival Following Isolated Heart Transplant Dale, R., Bahatyrevich, N., Leipzig, M., Currie, M. ELSEVIER SCIENCE INC. 2024: S74

  View details for Web of Science ID 001281353100138

• Misalignment of Ethics and Statistical Risk Models in Organ Allocation Dale, R., Cheng, M., Pines, K., Currie, M. ELSEVIER SCIENCE INC. 2024: S260

  View details for Web of Science ID 001281353101187

• Utilizing Machine Learning Clustering Trees to Risk Stratify Exception patients in Heart Transplantation Dale, R., Anyetei-Anum, G., Bahatyrevich, N., Pines, K., Leipzig, M., Currie, M. ELSEVIER SCIENCE INC. 2024: S78

  View details for Web of Science ID 001281353100145

• Causal Nonlinear Dose Response Analysis of Predicted Heart Mass Mismatching Dale, R., Leipzig, M., Bahatyrevich, N., Currie, M. ELSEVIER SCIENCE INC. 2024: S574

  View details for Web of Science ID 001281353103001

• Donor-Recipient Sex-Mismatching in Isolated Heart Transplant Confers No Postoperative Risk as Established by Equivalence Testing and Causal Estimation Dale, R., Leipzig, M., Bahatyrevich, N., Pines, K., Chen, Q., Teuteberg, J., Woo, J., Currie, M. ELSEVIER SCIENCE INC. 2024: S574-S575

  View details for Web of Science ID 001281353103002

• Trends in the Use of Exception Status since Implementation of 2018 United Network for Organ Sharing Single-Organ Adult Heart Transplant and Its Relation to Postoperative Survival Outcomes Dale, R., Leipzig, M., Pines, K., Chen, Q., Currie, M. E. LIPPINCOTT WILLIAMS & WILKINS. 2023: S65-S66

  View details for Web of Science ID 001094086300118

• Outcomes of Patients Undergoing Combined Heart-Kidney Transplantation With or Without Prior Ventricular Assist Device. Transplantation proceedings Currie, M., Leipzig, M., Kaghazchi, A., Zhu, Y., Shudo, Y., Woo, Y. J. 2023

  Abstract

  BACKGROUND: Both combined heart-kidney transplantation and ventricular assist devices (VADs) pose significant challenges, including sensitization, immunosuppressive treatment, and infrastructure demands. Despite these challenges, we hypothesized that the recipients of combined heart-kidney transplants with and without VADs would have equivalent survival. We aimed to compare the survival of heart-kidney transplant recipients with and without prior VAD placement.METHODS: We retrospectively analyzed all patients enrolled in the United Network for Organ Sharing database who underwent heart-kidney transplants. We created a matched cohort of patients undergoing heart-kidney transplantation with or without prior VAD using 1:1 nearest propensity-score matching with preoperative variables.RESULTS: In the propensity-matched cohort, 399 patients underwent heart-kidney transplantation with prior VAD, and 399 underwent heart-kidney transplantation without prior VAD. The estimated survival of heart--kidney recipients with prior VAD was 84.8% at one year, 81.2% at 3 years, and 75.3% at 5 years. The estimated survival of heart-kidney recipients without prior VAD was 86.8.7% at one year, 84.0% at 3 years, and 78.8% at 5 years. There was no statistically significant difference in the survival of heart-kidney transplant recipients with or without prior VAD at one year (P=.42; Figure 2), 3 years (P=.34), or 5 years (P=.30).CONCLUSION: Despite the increased challenge of heart-kidney transplantation in recipients with prior VAD, we demonstrated that these patients have similar survival to those who underwent heart-kidney transplantation without previous VAD placement.

  View details for DOI 10.1016/j.transproceed.2023.04.037

  View details for PubMedID 37393169

• World's first en bloc heart-lung transplantation using the paragonix lungguard donor preservation system. Journal of cardiothoracic surgery Neto, D., Guenthart, B., Shudo, Y., Currie, M. E. 2023; 18 (1): 131

  Abstract

  We present the first en bloc heart-lung donor transplant procurement using the Paragonix LUNGguard™ donor preservation system. This system offers reliable static hypothermic conditions designed to prevent major complications such as cold ischemic injury, uneven cooling and physical damage. While this represents a single case, the encouraging results warrant further investigation.

  View details for DOI 10.1186/s13019-023-02281-7

  View details for PubMedID 37041582

  View details for PubMedCentralID PMC10091844

• Successful Heart Transplantation Using a Portable Normothermic Ex-Vivo Donor Heart Preservation System for Extended Criteria Donor after Circulatory Death: A Case Series with Extended Perfusion Times Ruaengsri, C., Shudo, Y., Malki, A., Neto, D., Chen, R., Bethencourt, D., Hiesinger, W., MacArthur, J., Currie, M., Boyd, J., Guenthart, B., Lee, A., Woo, J. ELSEVIER SCIENCE INC. 2023: S467-S468

  View details for Web of Science ID 000992480601308

• Outcomes of Patients Undergoing Combined Heart-Kidney Transplantation with or without Prior Ventricular Assist Device Currie, M. E., Leipzig, M., Kaghazchi, A., Shudo, Y., Woo, Y. J. ELSEVIER SCIENCE INC. 2022: S85-S86

  View details for Web of Science ID 000780119700176

• Predicting Survival in Combined Heart-Liver Transplantation Compared to Heart Transplantation Alone Currie, M. E., Rinewalt, D. E., Leipzig, M., Shudo, Y., Kaghazchi, A., Zhu, Y., Woo, Y. J. ELSEVIER SCIENCE INC. 2022: S84-S85

  View details for Web of Science ID 000780119700173

• Post-Transplant Extracorporeal Membrane Oxygenation for Severe Primary Graft Dysfunction to Support the Use of Marginal Donor Hearts. Transplant international : official journal of the European Society for Organ Transplantation Shudo, Y., Alassar, A., Wang, H., Lingala, B., He, H., Zhu, Y., Hiesinger, W., MacArthur, J. W., Boyd, J. H., Lee, A. M., Currie, M., Woo, Y. J. 2022; 35: 10176

  Abstract

  Severe primary graft dysfunction (PGD) is the leading cause of early postoperative mortality following orthotopic heart transplantation (OHT). Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) has been used as salvage therapy. This study aimed to evaluate the outcomes in adult OHT recipients who underwent VA-ECMO for severe PGD. We retrospectively reviewed 899 adult (≥18years) patients who underwent primary OHT at our institution between 1997 and 2017. Recipients treated with VA-ECMO (19, 2.1%) exhibited a higher incidence of previous cardiac surgery (p = .0220), chronic obstructive pulmonary disease (p = .0352), and treatment with a calcium channel blocker (p = .0018) and amiodarone (p = .0148). Cardiopulmonary bypass (p = .0410) and aortic cross-clamp times (p = .0477) were longer in the VA-ECMO cohort and they were more likely to have received postoperative transfusion (p = .0013); intra-aortic balloon pump (IABP, p < .0001), and reoperation for bleeding or tamponade (p < .0001). The 30-day, 1-year, and overall survival after transplantation of non-ECMO patients were 95.9, 88.8, and 67.4%, respectively, compared to 73.7, 57.9, and 47.4%, respectively in the ECMO cohort. Fourteen (73.7%) of the ECMO patients were weaned after a median of 7days following OHT (range: 1-12days). Following OHT, VA-ECMO may be a useful salvage therapy for severe PGD and can potentially support the usage of marginal donor hearts.

  View details for DOI 10.3389/ti.2022.10176

  View details for PubMedID 35340846

• Expanding the armamentarium for reoperative coronary artery bypass grafting JOURNAL OF CARDIAC SURGERY Currie, M. 2021

  View details for DOI 10.1111/jocs.15901

  View details for Web of Science ID 000682717600001

  View details for PubMedID 34365672

• Relation of Length of Survival After Orthotopic Heart Transplantation to Age of the Donor. The American journal of cardiology Shudo, Y., Guenther, S. P., Lingala, B., He, H., Hiesinger, W., MacArthur, J. W., Currie, M. E., Lee, A. M., Boyd, J. H., Woo, Y. J. 2020

  Abstract

  We aim to evaluate the impact of donor age on the outcomes in orthotropic heart transplantation recipients. The United Network for Organ Sharing database was queried for adult patients (age; ≥60) underwent first-time orthotropic heart transplantation between 1987 and 2019 (n = 18,447). We stratified the cohort by donor age; 1,702 patients (9.2%) received a heart from a donor age of <17 years; 11,307 patients (61.3%) from a donor age of 17 ≥, < 40; 3,525 patients (19.1%) from a donor age of 40 ≥, < 50); and 1,913 patients (10.4%) from a donor age of ≥50. There was a significant difference in the survival likelihood (p < 0.0001) based on donor's age-based categorized cohort, however, the median survival was 10.5 years in the cohort in whom the donor was <17, 10.3 years in whom the donor was 17 ≥, < 40, 9.4 years in whom the donor was 40 ≥, < 50, and 9.0 years in whom the donor was ≥ 50. Additionally, there was no significant difference in the episode of acute rejection (p = 0.19) nor primary graft failure (p = 0.24). In conclusion, this study demonstrated that patients receiving hearts from the donor age of ≥50 years old showed slight inferior survival likelihood, but appeared to be equivalent median survival.

  View details for DOI 10.1016/j.amjcard.2020.06.036

  View details for PubMedID 32736794

• Malignancy Following Heart Transplant: Few and Far Between Chang, E., Moayedi, Y., Hoppenfeld, M., Lafreniere-Roula, M., Fan, S., Henricksen, E. J., Feng, K., Morales, D. P., Purewal, S., Duclos, S., Lee, R., Lyapin, A., Currie, M., Ross, H. J., Teuteberg, J. J., Khush, K. K. ELSEVIER SCIENCE INC. 2020: S282–S283

  View details for Web of Science ID 000522637202041

• Impact of Surgical Approach in Double Lung Transplantation: Median Sternotomy vs Clamshell Thoracotomy. Transplantation proceedings Shudo, Y. n., Rinewalt, D. n., Lingala, B. n., Kim, F. Y., He, H. n., Boyd, J. H., Lee, A. M., Hiesinger, W. n., Currie, M. E., MacArthur, J. W., Woo, Y. J. 2020

  Abstract

  Double lung transplantation (DLT) remains the gold standard for end-stage lung disease. Although DLT was historically performed via clamshell thoracotomy, recently the median sternotomy has emerged as a viable alternative. As the ideal surgical approach remains unclear, the aim of our study was to compare the short- and long-term outcomes of these 2 surgical approaches in DLT.We retrospectively reviewed 192 consecutive adult patients who underwent primary DLT at our institution between 2012 and 2017 (sternotomy, n = 147; clamshell, n = 45). The impact of each surgical approach on post-transplant morbidity was investigated, and the overall survival probability analyses were performed.There were no significant differences in recipients' baseline and donors' characteristics and bilateral allograft ischemic time. Freedom from primary graft dysfunction, acute rejection episodes, postoperative prolonged ventilator support, tracheostomy, postoperative stroke, and airway dehiscence were comparable between these 2 groups. The duration of cardiopulmonary bypass and operative time were significantly longer in the clamshell thoracotomy group. Postoperative extracorporeal membrane oxygenation usage tended to be more frequent in the clamshell thoracotomy group than the median sternotomy group, despite no statistical significance. Length of hospital and intensive care unit stay were not influenced by the type of incision. There was no significant difference in overall survival between these 2 procedure groups (P = .61, log-rank test).The median sternotomy approach in DLT decreases operative time and more importantly leads to a shorter duration of cardiopulmonary bypass. The type of surgical approach did not show any statistically significant impact on adult DLT recipients' morbidity and survival.

  View details for DOI 10.1016/j.transproceed.2019.10.018

  View details for PubMedID 31911057

• Impact of Surgical Approach in Double Lung Transplantation: Median Sternotomy Decreases Operative and Cardiopulmonary Bypass Time Compared to Clamshell Thoracotomy Shudo, Y., Rinewalt, D., Lingala, B., Kim, F. Y., He, H., Boyd, J. H., Lee, A. M., Hiesinger, W., Currie, M. E., MacArthur, J. W., Woo, J. ELSEVIER SCIENCE INC. 2019: S414

  View details for DOI 10.1016/j.healun.2019.01.1054

  View details for Web of Science ID 000461365103045

• Comparison of Patients Undergoing Multiorgan Transplantation with or without Prior Ventricular Assist Device Currie, M. E., Banerjee, D., Shudo, Y., Lingala, B., Zhu, Y., Haddad, F., Woo, J. ELSEVIER SCIENCE INC. 2019: S216–S217

  View details for DOI 10.1016/j.healun.2019.01.527

  View details for Web of Science ID 000461365101212

• Successful Heart-Lung Transplant for a Patient on Continuous-Flow Left Ventricular Assist Device Support Complicated With Amiodarone-Induced Pulmonary Fibrosis TRANSPLANTATION PROCEEDINGS Currie, M. E., Shudo, Y., Mooney, J., Woo, Y. J. 2019; 51 (2): 593–94

  View details for DOI 10.1016/j.transproceed.2018.12.024

  View details for Web of Science ID 000473378100086

• Successful Heart-Lung Transplant for a Patient on Continuous-Flow Left Ventricular Assist Device Support Complicated With Amiodarone-Induced Pulmonary Fibrosis. Transplantation proceedings Currie, M. E., Shudo, Y., Mooney, J., Woo, Y. J. 2019; 51 (2): 593–94

  Abstract

  In this case report, we present a successful case of en bloc heart-lung transplant in a patient with advanced cardiopulmonary respiratory failure from amiodarone-associated pulmonary fibrosis that occurred post-left ventricular assist device implantation.

  View details for PubMedID 30879597

• Evaluation of Risk Factors for Heart-Lung Transplant Recipient Outcome: An Analysis of the United Network for Organ Sharing Database. Circulation Shudo, Y. n., Wang, H. n., Lingala, B. n., He, H. n., Kim, F. Y., Hiesinger, W. n., Lee, A. M., Boyd, J. H., Currie, M. n., Woo, Y. J. 2019; 140 (15): 1261–72

  Abstract

  Heart-lung transplantation (HLTx) is an effective treatment for patients with advanced cardiopulmonary failure. However, no large multicenter study has focused on the relationship between donor and recipient risk factors and post-HLTx outcomes. Thus, we investigated this issue using data from the United Network for Organ Sharing database.All adult patients (age ≥18 years) registered in the United Network for Organ Sharing database who underwent HLTx between 1987 and 2017 were included (n=997). We stratified the cohort by patients who were alive without retransplant at 1 year (n=664) and patients who died or underwent retransplant within 1 year of HLTx (n=333). The primary outcome was the influence of donor and recipient characteristics on 1-year post-HLTx recipient death or retransplant. Kaplan-Meier curves were created to assess overall freedom from death or retransplant. To obtain a better effect estimation on hazard and survival time, the parametric Accelerated Failure Time model was chosen to perform time-to-event modeling analyses.Overall graft survival at 1-year post-HLTx was 66.6%. Of donors, 53% were male, and the mean age was 28.2 years. Univariable analysis showed advanced donor age, recipient male sex, recipient creatinine, recipient history of prior cardiac or lung surgery, recipient extracorporeal membrane oxygenation support, transplant year, and transplant center volume were associated with 1-year post-HLTx death or retransplant. On multivariable analysis, advanced donor age (hazard ratio [HR], 1.017; P=0.0007), recipient male sex (HR, 1.701; P=0.0002), recipient extracorporeal membrane oxygenation support (HR, 4.854; P<0.0001), transplant year (HR, 0.962; P<0.0001), and transplantation at low-volume (HR, 1.694) and medium-volume centers (HR, 1.455) in comparison with high-volume centers (P=0.0007) remained as significant predictors of death or retransplant. These predictors were incorporated into an equation capable of estimating the preliminary probability of graft survival at 1-year post-HLTx on the basis of preoperative factors alone.HLTx outcomes may be improved by considering the strong influence of donor age, recipient sex, recipient hemodynamic status, and transplant center volume. Marginal donors and recipients without significant factors contributing to poor post-HLTx outcomes may still be considered for transplantation, potentially with less impact on the risk of early postoperative death or retransplant.

  View details for DOI 10.1161/CIRCULATIONAHA.119.040682

  View details for PubMedID 31589491

• Successful Outcome Following Orthotopic Heart Transplantation With a Donor Half Way Across The Country. Transplantation proceedings Currie, M. E., Shudo, Y., Woo, Y. J. 2018; 50 (10): 4062–63

  Abstract

  Orthotopic heart transplantation is the criterion standard treatment for end-stage heart failure and the number of recipient candidates has been increasing. Despite this increasing demand, there is limited donor organ supply. In order to surmount this challenge, we propose harvesting donor hearts from more distant locations and accepting longer cold ischemic times. The usual accepted total ischemic time limit for the transplanted human heart is up to 4 hours. Here, we report the successful use of a donor heart from 1268 miles away with a total allograft ischemic time greater than 6 hours.

  View details for PubMedID 30577315

• Successful Outcome Following Orthotopic Heart Transplantation With a Donor Half Way Across The Country TRANSPLANTATION PROCEEDINGS Currie, M. E., Shudo, Y., Woo, Y. J. 2018; 50 (10): 4062–63

  View details for DOI 10.1016/j.transproceed.2018.09.014

  View details for Web of Science ID 000454972000196

• The role of visual and direct force feedback in robotics-assisted mitral valve annuloplasty INTERNATIONAL JOURNAL OF MEDICAL ROBOTICS AND COMPUTER ASSISTED SURGERY Currie, M. E., Talasaz, A., Rayman, R., Chu, M. A., Kiaii, B., Peters, T., Trejos, A., Patel, R. 2017; 13 (3)

  Abstract

  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.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.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 < 0.05).To achieve better control of interaction forces on cardiac tissue during robotics-assisted mitral valve annuloplasty suturing, force feedback may be required.

  View details for DOI 10.1002/rcs.1787

  View details for Web of Science ID 000411294000020

  View details for PubMedID 27862833

• Phantom study of an ultrasound guidance system for transcatheter aortic valve implantation COMPUTERIZED MEDICAL IMAGING AND GRAPHICS McLeod, A., Currie, M. E., Moore, J. T., Bainbridge, D., Kiaii, B. B., Chu, M. A., Peters, T. M. 2016; 50: 24–30

  Abstract

  A guidance system using transesophageal echocardiography and magnetic tracking is presented which avoids the use of nephrotoxic contrast agents and ionizing radiation required for traditional fluoroscopically guided procedures. The aortic valve is identified in tracked biplane transesophageal echocardiography and used to guide stent deployment in a mixed reality environment. Additionally, a transapical delivery tool with intracardiac echocardiography capable of monitoring stent deployment was created. This system resulted in a deployment depth error of 3.4mm in a phantom. This was further improved to 2.3mm with the custom-made delivery tool. In comparison, the variability in deployment depth for traditional fluoroscopic guidance was estimated at 3.4mm.

  View details for DOI 10.1016/j.compmedimag.2014.12.001

  View details for Web of Science ID 000376833600004

  View details for PubMedID 25595049

• Augmented Reality System for Ultrasound Guidance of Transcatheter Aortic Valve Implantation INNOVATIONS-TECHNOLOGY AND TECHNIQUES IN CARDIOTHORACIC AND VASCULAR SURGERY Currie, M. E., McLeod, A., Moore, J. T., Chu, M. A., Patel, R., Kiaii, B., Peters, T. M. 2016; 11 (1): 31–39

  Abstract

  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.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.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.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.

  View details for DOI 10.1097/IMI.0000000000000235

  View details for Web of Science ID 000377677200006

  View details for PubMedID 26938173

• Dual antiplatelet therapy use by Canadian cardiac surgeons JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY Yanagawa, B., Ruel, M., Bonneau, C., Lee, M. M., Chung, J., Al Shouli, S., Fagan, A., Al Khalifa, A., White, C. W., Yamashita, M. H., Currie, M. E., Teoh, H., Mewhort, H. M., Verma, S. 2015; 150 (6): 1548–U260

  Abstract

  Dual antiplatelet therapy is the cornerstone treatment for patients with acute coronary syndrome. Recent Canadian Guidelines recommend the use of dual antiplatelet therapy for 1 year after coronary artery bypass grafting in patients with acute coronary syndrome, but considerable variability remains.We performed a survey of 75 Canadian cardiac surgeons to assess the use of dual antiplatelet therapy.Whereas 58.6% of respondents indicated that the benefits of dual antiplatelet therapy were seen irrespective of how patients were managed after acute coronary syndrome, 36.2% believed that the benefits of dual antiplatelet therapy were limited to those treated medically or percutaneously. In regard to the timing of dual antiplatelet therapy administration, 57% of respondents indicated that dual antiplatelet therapy should be given upstream in the emergency department, whereas 36.2% responded that dual antiplatelet therapy should be given only once the coronary anatomy has been defined. The majority surveyed (81%) weighed bleeding risk as being more important than ischemic risk reduction. In stable patients after acute coronary syndrome, the majority of surgeons would wait approximately 4 days after the last dose of P2Y12 antagonist before coronary artery bypass grafting. Only 44.6% indicated that they routinely use dual antiplatelet therapy postrevascularization in the setting of acute coronary syndrome. Rather, most surgeons use dual antiplatelet therapy for select patients, such as those with a stented vessel without a bypass graft, endarterectomy, or off-pump coronary artery bypass grafting.Cardiac surgeons exhibit variation in their attitudes and practice patterns toward dual antiplatelet therapy after coronary artery bypass grafting, and in approximately half of cases, their practice does not adhere to current guideline recommendations. New trials focusing on coronary artery bypass grafting cases in their primary analysis and educational initiatives for surgeons that focus on guideline recommendations may be warranted.

  View details for DOI 10.1016/j.jtcvs.2015.08.066

  View details for Web of Science ID 000365040700051

  View details for PubMedID 26395051

• Recalcitrant Prosthetic Valve Endocarditis Requiring Repeated Reconstruction: Running Out of Options CANADIAN JOURNAL OF CARDIOLOGY Pepe, D. L., Anantha, R. V., Currie, M. E., McCormick, J. K., Mele, T., Chu, M. A. 2014; 30 (12): 1732.e5–8

  Abstract

  In this report we describe a previously healthy 36-year-old man who presented with septic shock secondary to bacterial endocarditis with multiple cerebral, mesenteric, and peripheral embolic phenomena. He underwent emergent porcine prosthetic valve replacement with aortic annular reconstruction. Subsequently, he developed recalcitrant Candida parapsilosis endocarditis requiring treatment with multiple antifungal agents and 4 repeated complex reconstructions of the aortic root and fibrous trigones over 3 years, before the infection was successfully controlled. This case underscores the significant morbidity associated with fungal endocarditis and importance of an early combined medical and surgical approach.

  View details for DOI 10.1016/j.cjca.2014.09.003

  View details for Web of Science ID 000345584400048

  View details for PubMedID 25475479

• Myocardium at Risk Is Associated With Adverse Clinical Events in Women but Not in Men, After Coronary Artery Bypass Grafting CANADIAN JOURNAL OF CARDIOLOGY Ouzounian, M., Currie, M. E., Buth, K. J., Yip, A. M., Hassan, A., Hirsch, G. M. 2014; 30 (7): 808–13

  Abstract

  Women undergoing coronary artery bypass grafting (CABG) are at increased risk for morbidity and mortality. Factors responsible for this observation include smaller coronary size and delayed presentation. To date, no studies have examined the effect of the degree of myocardium at risk (MAR) on the relationship between female sex and adverse postoperative events.Consecutive patients undergoing first-time isolated CABG at a single institution from 2002-2007 were identified. MAR was calculated using the weighted Duke Index and was categorized as low, moderate, or high. Multivariable logistic regression models were created to compare the impact of MAR on adverse clinical events.We identified 3741 patients, 3325 (89%) of whom had complete angiographic data. Women (n = 755) were older (P = 0.0001) and presented more often with hypertension (P = 0.0001), diabetes (P = 0.0001), heart failure (P = 0.0001), and an urgent/emergent situation (P = 0.002). After surgery, women experienced greater rates of adverse events (15.2% vs 9.3%; P = 0.0001). In a fully adjusted logistic regression model, the nested interaction of sex in MAR showed that women had a significantly greater risk of major adverse cardiovascular events (MACE) when MAR was high (odds ratio [OR], 1.9; 95% confidence interval [CI], 1.3-2.6; P = 0.0004). Greater severity of MAR emerged as an independent predictor of adverse events among women (high: OR, 2.9; 95% CI, 1.2-7.3; moderate: OR, 2.2; 95% CI, 0.8-5.7; low: OR, 1.0), but not among men.MAR was independently associated with higher rates of adverse events among women but not in men undergoing CABG. This finding may help explain differences in outcomes seen between women and men after revascularization.

  View details for DOI 10.1016/j.cjca.2014.03.039

  View details for Web of Science ID 000339981300015

  View details for PubMedID 24880935

• Knowledge, attitudes, and practice patterns in surgical management of bicuspid aortopathy: A survey of 100 cardiac surgeons JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY Verma, S., Yanagawa, B., Kalra, S., Ruel, M., Peterson, M. D., Yamashita, M. H., Fagan, A., Currie, M. E., White, C. W., Sang, S., Rosu, C., Singh, S., Mewhort, H., Gupta, N., Fedak, P. M. 2013; 146 (5): 1033–40

  Abstract

  Clinical practice guidelines have been established for surgical management of the aorta in bicuspid aortic valve disease. We hypothesized that surgeons' knowledge of and attitudes toward bicuspid aortic valve aortopathy influence their surgical approaches.We surveyed cardiac surgeons to probe the knowledge of, attitudes toward, and surgical management of bicuspid aortopathy. A total of 100 Canadian adult cardiac surgeons participated.Fifty-two percent of surgeons believed that the mechanism underlying aortic dilation in those with bicuspid aortic valve was due to an inherent genetic abnormality of the aorta, whereas only 2% believed that altered valve-related processes were involved in this process. Only a minority (15%) believed that bicuspid valve leaflet fusion type is associated with a unique pattern of aortic dilatation aortic phenotype. Sixty-five percent of surgeons recommended echocardiographic screening of first-degree relatives of patients with bicuspid aortic valve. Most surgeons (61%) elected to replace the aorta when the diameter is 45 mm or greater at the time of valve surgery. Fifty-five percent of surgeons surveyed suggested that in the absence of concomitant valvular disease, they would recommend ascending aortic replacement at a threshold of 50 mm or greater. Approximately one third of surgeons suggested that they would elect to replace a mildly dilated ascending aorta (40 mm) at the time of valve surgery. The most common surgical approach (61%) for combined valve and aortic surgery was aortic valve replacement and supracoronary replacement of the ascending aorta, and only a minority suggested the use of deep hypothermic circulatory arrest and open distal anastomosis. More aggressive approaches were favored with greater surgeon experience, and when circulatory arrest was chosen, the majority (68%) suggested they would use antegrade cerebral perfusion. In the setting of aortic insufficiency and a dilated aorta, 42% of surgeons suggested that they would perform valve-sparing surgery. Of note, 40% of respondents used an index measure of aortic size to body surface area in addition to absolute aortic diameter in assessing the threshold for intervention.This large survey uncovered significant gaps in the knowledge and attitudes of surgeons toward the diagnosis and management of bicuspid aortopathy, many of which were at odds with current guideline recommendations. Efforts to promote knowledge translation in this area are strongly encouraged.

  View details for DOI 10.1016/j.jtcvs.2013.06.037

  View details for Web of Science ID 000325603300008

  View details for PubMedID 23988289

• Evaluating the Effect of Three-Dimensional Visualization on Force Application and Performance Time During Robotics-Assisted Mitral Valve Repair INNOVATIONS-TECHNOLOGY AND TECHNIQUES IN CARDIOTHORACIC AND VASCULAR SURGERY Currie, M. E., Trejos, A., Rayman, R., Chu, M. A., Patel, R., Peters, T., Kiaii, B. B. 2013; 8 (3): 199–205

  Abstract

  The purpose of this study was to determine the effect of three-dimensional (3D) binocular, stereoscopic, and two-dimensional (2D) monocular visualization on robotics-assisted mitral valve annuloplasty versus conventional techniques in an ex vivo animal model. In addition, we sought to determine whether these effects were consistent between novices and experts in robotics-assisted cardiac surgery.A cardiac surgery test-bed was constructed to measure forces applied during mitral valve annuloplasty. Sutures were passed through the porcine mitral valve annulus by the participants with different levels of experience in robotics-assisted surgery and tied in place using both robotics-assisted and conventional surgery techniques.The mean time for both the experts and the novices using 3D visualization was significantly less than that required using 2D vision (P < 0.001). However, there was no significant difference in the maximum force applied by the novices to the mitral valve during suturing (P = 0.7) and suture tying (P = 0.6) using either 2D or 3D visualization. The mean time required and forces applied by both the experts and the novices were significantly less using the conventional surgical technique than when using the robotic system with either 2D or 3D vision (P < 0.001).Despite high-quality binocular images, both the experts and the novices applied significantly more force to the cardiac tissue during 3D robotics-assisted mitral valve annuloplasty than during conventional open mitral valve annuloplasty. This finding suggests that 3D visualization does not fully compensate for the absence of haptic feedback in robotics-assisted cardiac surgery.

  View details for DOI 10.1097/imi.0b013e3182a3200e

  View details for Web of Science ID 000217630100005

  View details for PubMedID 23989813

• A Navigation Platform for Guidance of Beating Heart Transapical Mitral Valve Repair IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING Moore, J. T., Chu, M. A., Kiaii, B., Bainbridge, D., Guiraudon, G., Wedlake, C., Currie, M., Rajchl, M., Patel, R. V., Peters, T. M. 2013; 60 (4): 1034–40

  Abstract

  Traditional surgical approaches for repairing diseased mitral valves (MVs) have relied on placing the patient on cardiopulmonary bypass (on pump), stopping the heart and accessing the arrested heart directly. However, because this approach has the potential for adverse neurological, vascular, and immunological sequelae, less invasive beating heart alternatives are desirable. Emerging beating heart techniques have been developed to offer high-risk patients MV repair using ultrasound guidance alone without stopping the heart. This paper describes the first porcine trials of the NeoChord DS1000 (Minnetonka, MN), employed to attach neochordae to a MV leaflet using the traditional ultrasound-guided protocol augmented by dynamic virtual geometric models. The distance errors of the tracked tool tip from the intended midline trajectory (5.2 ± 2.4 mm versus 16.8 ± 10.9 mm, p = 0.003), navigation times (16.7 ± 8.0 s versus 92.0 ± 84.5 s, p = 0.004), and total path lengths (225.2 ± 120.3 mm versus 1128.9 ± 931.1 mm, p = 0.003) were significantly shorter in the augmented ultrasound compared to navigation with ultrasound alone, indicating a substantial improvement in the safety and simplicity of the procedure.

  View details for DOI 10.1109/TBME.2012.2222405

  View details for Web of Science ID 000316812200020

  View details for PubMedID 23047858

• Can internal thoracic arteries be used for both coronary artery bypass and breast reconstruction? INTERACTIVE CARDIOVASCULAR AND THORACIC SURGERY Currie, M. E., Fox, S. A., Greer-Bayramoglu, R. J., Fortin, A. J., Chu, M. A. 2012; 15 (5): 811–15

  Abstract

  Recently, the internal thoracic arteries have been preferentially used in autologous breast reconstruction at the levels of the third or fourth intercostal spaces. This may compromise future treatment of occult coronary disease. We hypothesized that internal thoracic artery length at the fourth intercostal space would allow both breast reconstruction and future coronary artery bypass grafting (CABG).Anatomic analysis of 20 female patients undergoing CABG was performed examining internal thoracic artery length from its origin to the third, fourth, fifth intercostal spaces and the left anterior descending (LAD) artery target.The left internal thoracic artery was anastamosed to the LAD target at a mean length of 11.4 ± 1.4 cm. The mean lengths of the pedicled left internal thoracic artery from its origin to the third, fourth and fifth intercostal space were 8.5 ± 1.0, 10.9 ± 1.2 and 13.0 ± 1.4 cm, respectively. Therefore, the left internal thoracic artery length was adequate at the fourth intercostal space in 6 of 20 (30%) patients.Dissection of the left internal thoracic artery to the fourth intercostal space would allow for concomitant use in CABG and breast reconstruction in one-third of cases. However, skeletonization of the internal thoracic artery at the level of the fourth intercostal space would be sufficient for CABG in all cases following autologous breast reconstruction.

  View details for DOI 10.1093/icvts/ivs366

  View details for Web of Science ID 000310224000001

  View details for PubMedID 22899665

  View details for PubMedCentralID PMC3480617

• Augmented Reality Image Guidance Improves Navigation for Beating Heart Mitral Valve Repair INNOVATIONS-TECHNOLOGY AND TECHNIQUES IN CARDIOTHORACIC AND VASCULAR SURGERY Chu, M. A., Moore, J., Peters, T., Bainbridge, D., McCarty, D., Guiraudon, G. M., Wedlake, C., Lang, P., Rajchl, M., Currie, M. E., Daly, R. C., Kiaii, B. 2012; 7 (4): 274–81

  Abstract

  Emerging off-pump beating heart valve repair techniques offer patients less invasive alternatives for mitral valve (MV) repair. However, most of these techniques rely on the limited spatial and temporal resolution of transesophageal echocardiography (TEE) alone, which can make tool visualization and guidance challenging.Using a magnetic tracking system and integrated sensors, we created an augmented reality (AR) environment displaying virtual representations of important intracardiac landmarks registered to biplane TEE imaging. In a porcine model, we evaluated the AR guidance system versus TEE alone using the transapically delivered NeoChord DS1000 system to perform MV repair with chordal reconstruction.Successful tool navigation from left ventricular apex to MV leaflet was achieved in 12 of 12 and 9 of 12 (P = 0.2) attempts with AR imaging and TEE alone, respectively. The distance errors of the tracked tool tip from the intended midline trajectory (5.2 ± 2.4 mm vs 16.8 ± 10.9 mm, P = 0.003), navigation times (16.7 ± 8.0 seconds vs 92.0 ± 84.5 seconds, P = 0.004), and total path lengths (225.2 ± 120.3 mm vs 1128.9 ± 931.1 mm, P = 0.003) were significantly shorter in the AR-guided trials compared with navigation with TEE alone. Furthermore, the potential for injury to other intracardiac structures was nearly 40-fold lower when using the AR imaging for tool navigation. The AR guidance also seemed to shorten the learning curve for novice surgeons.Augmented reality-enhanced TEE facilitates more direct and safe intracardiac navigation of the NeoChord DS tool from left ventricular apex to MV leaflet. Tracked tool path results demonstrate fourfold improved accuracy, fivefold shorter navigation times, and overall improved safety with AR imaging guidance.

  View details for DOI 10.1097/imi.0b013e31827439ea

  View details for Web of Science ID 000217612800008

  View details for PubMedID 23123995

• Long-Term Angiographic Follow-Up of Robotic-Assisted Coronary Artery Revascularization ANNALS OF THORACIC SURGERY Currie, M. E., Romsa, J., Fox, S. A., Vezina, W. C., Akincioglu, C., Warrington, J. C., McClure, R., Stitt, L. W., Menkis, A. H., Boyd, W., Kiaii, B. 2012; 93 (5): 1426–31

  Abstract

  Robotic-assisted coronary artery bypass grafting (CABG) has been shown in short-term studies to increase patient satisfaction and to reduce surgical morbidity and recovery times. However, the long-term patency rate of robotic-assisted CABG is unknown. Therefore, the objective of this study was to assess the long-term patency rate of robotic-assisted coronary artery bypass grafts.The study cohort included all patients who underwent robotic-assisted conduit dissection for CABG at London Health Sciences Centre between September 1999 and December 2003. These patients had selective graft patency assessment using cardiac catheterization or computed tomography angiography (CTA), or both, and stress myocardial perfusion scintigraphy (MPS) 5 to 10 years after surgery to evaluate graft patency and to give functional information on the hemodynamic significance of any graft stenosis. Patients also completed quality of life questionnaires.From a total of 160 patients who underwent robotic-assisted CABG, 82 eligible patients were followed with graft patency assessments for a mean period of 8 years±16.3 months. The patency rate of all robotic-assisted CABG grafts in this patient cohort was 92.7%. The patency rate of left internal thoracic artery grafts to the left anterior descending artery after robotic-assisted CABG in this patient cohort was 93.4%. Patients consistently attained high scores on quality of life questionnaires after surgery.The long-term patency rate of grafts after robotic-assisted CABG was 92.7% at a mean follow-up period of 95.8±16.3 months. Specifically, the patency rate of left internal thoracic artery grafts to the left anterior descending artery after robotic-assisted CABG was 93.4%.

  View details for DOI 10.1016/j.athoracsur.2011.11.031

  View details for Web of Science ID 000303539200013

  View details for PubMedID 22342992

• The role of three-dimensional visualization in robotics-assisted cardiac surgery Currie, M., Trejos, A., Rayman, R., Chu, M. A., Patel, R., Peters, T., Kiaii, B., Holmes, D. R., Wong, K. H. SPIE-INT SOC OPTICAL ENGINEERING. 2012

  View details for DOI 10.1117/12.911714

  View details for Web of Science ID 000305070200015

• Immunologic targets in the etiology of allograft vasculopathy: Endothelium versus media TRANSPLANT IMMUNOLOGY Currie, M., Zaki, A. M., Nejat, S., Hirsch, G. M., Lee, T. G. 2008; 19 (2): 120–26

  Abstract

  The respective roles of the endothelium and the media as allo-immune targets in the generation of allograft vasculopathy (AV) have yet to be clearly defined. Although endothelial damage has been implicated in the progression of AV, evidence from mechanical vascular injury models suggests that medial injury may play a more dominant role. The overall objective of this research was to determine the relative importance of the endothelium versus the media as a target for immune injury and induction of AV. To investigate this we developed a novel model which involved the creation of chimeric aortic segments. To accomplish this we removed aortic segments from C3H/HeJ (C3H) mice and stripped them of endothelium by a short pulse with EDTA. The stripped C3H grafts were implanted into immunodeficient C57BL/6 (B6) RAG1(-/-) mice for a period of 21 days. As the immunodeficient mice did not mount an allo-immune response to the grafts, the endothelium was renewed by normal repair mechanisms. The new endothelium was recipient in origin, resulting in a chimeric graft with C3H media and B6 endothelium. We confirmed complete denudement by immunocytochemistry for endothelial specific markers, as well as by transmission and scanning electron microscopy. Replacement of endothelium with recipient endothelial cells was confirmed by immunocytochemistry, electron microscopy and by using a green fluorescent protein mouse transplant combination. Subsequent re-transplantation of the chimeric grafts into either B6 or C3H recipients demonstrated that an allogeneic media is more important than an allogeneic endothelium in inducing robust AV.

  View details for DOI 10.1016/j.trim.2008.03.002

  View details for Web of Science ID 000257002400005

  View details for PubMedID 18503887