Catheterization and Cardiovascular Interventions 83:647–648 (2014)
Editorial Comment The Learning Curve in New Structural Interventions Charles A. Henrikson, MD, FHRS, and Joaquin E. Cigarroa,* MD, FACC, FSCAI Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon 97201
New procedures are often accompanied by a “learning curve,” which refers to the fact that an operator and their support staff may have more difficulties in patient selection and the performance of a procedure. Learning curves often translate into higher complication rates, at the initiation of a new procedure, but with experience, the difficulties will decrease to a certain baseline complication level. The learning curve creates a dilemma for both patients and operators—a reasonable patient does not want to be the first to have a new procedure, especially if there are alternatives, and the operator is put in a classic bind, needing to recruit patients for the new procedure, but knowing that the risk of being one of the first patients is often higher than that of a later patients. The article by Cruz-Gonzalez et al. [1] in this month’s journal looks at their single center experience with the Amplatzer Cardiac Plug (ACP) and the Watchman left atrial appendage occluder devices. Although the numbers are small, they demonstrate a high early complication rate (3/10 patients) followed by a dramatic drop (0/21 patients). The novel aspect of their paper is the comparison of the ACP to the Watchman. The early group was comprised of the first 10 ACP patients, and these were compared to 11 later ACP patients and the first 10 Watchman patients. The authors conclude that there was overlap in the learning curve for the ACP and Watchman procedures, and attribute the lack of complications in the first 10 Watchman patients to this. Again, the numbers are very small, making it quite difficult to draw conclusions. In the three major studies of the Watchman device, PROTECT AF, the continuing access protocol (CAP), and PREVAIL, clearer conclusions can be drawn. PROTECT AF [2], was the first randomized trial of the Watchman, taking patients with a CHADS2 score of 1 or high and randomizing 2:1 to Watchman vs. warfarin. A total of 592 patients underwent attempted Watchman placement. After PROTECT was closed, C 2014 Wiley Periodicals, Inc. V
study sites still had access to the device under CAP, and another 460 were implanted. Then, the PREVAIL study was started, for patients with a CHADS2 score of 2 or higher, again randomized 2:1 to Watchman. Interesting aspects of the learning curve emerge [2]. In the first half of the PROTECT AF trial, the complication rate was 10.0% which dropped to 5.5% for the second half of PROTECT. In CAP and PREVAIL, the complication rates were 3.7 and 4.2%, respectively. Recent data regarding PREVAIL was presented at a FDA panel and revealed no difference in complication rates between the experienced operators (who had been part of PROTECT and CAP) and new operators (who started placing the Watchman in PREVAIL). The most likely explanation for this is the implementation of extensive mandatory training for new sites and new operators in PREVAIL. Following identification of new sites, the training includes extensive online training, an examination, in person training, proctoring by company personnel or experienced physicians, and ongoing case support by industry personnel. Impressively, by the PREVAIL data, this approach seems to have worked. The Cruz-Gonzalez paper hints at another method for shifting the learning curve [1]. There is an implication (although the numbers are very small) that the learning curve for the ACP can substitute for the learning curve for the Watchman. There is certainly some logic to this, as they are similar devices and access and deployment are similar. The main dangers in both of these devices are the transseptal puncture and manipulating the device in the thin-walled left atrial appendage. Although all new operators should go through the required training, those with experience using similar devices would likely achieve independence earlier than an operator without such experience. Conflict of Interest: Nothing to report. *Correspondence to: Joaquin E. Cigarroa, MD, Knight Cardiovascular Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, UHN 62, Portland, OR 97201. E-mail: [email protected] Received 7 January 2014; Revision accepted 12 January 2014 DOI: 10.1002/ccd.25400 Published online 24 February 2014 in Wiley Online Library (wileyonlinelibrary.com)
648
Henrikson and Cigarroa
As operators, we all have a responsibility to patients to try to minimize the learning curve as much as possible, ideally shifting the learning curve to preclinical models or simulators. As demonstrated by Watchman, proficiency in coronary and electrophysiology procedures does not translate into low complication rates in structural left appendage work. For our patients, we must ensure comprehensive training by physicians and industry, often incorporating specific aspects including an understanding of equipment design, anatomic variation, procedural components, and where feasible simulation training and proctoring. Experience in
PROTECT AF, CAP, and PREVAIL trials demonstrate this is possible and beneficial. REFERENCES 1. Cruz-Gonzalez I, Perez-Rivera A, Lopez-Jimenez R, et al. Significance of the learning curve in left atrial appendage occlusion with two different devices. Catheter Cardiovasc Interv 2014;83:642–646. 2. Reddy VY, Holomes D, Doshi SK, et al. Safety of percutaneous left atrial appendage closure: Results from the Watchman left atrial appendage system for embolic protection in patients with AF (PROTECT AF) clinical trial and the continued access registry. Circulation 2011;123:417–424.
Catheterization and Cardiovascular Interventions DOI 10.1002/ccd. Published on behalf of The Society for Cardiovascular Angiography and Interventions (SCAI).
Editorial Comment The Learning Curve in New Structural Interventions Charles A. Henrikson, MD, FHRS, and Joaquin E. Cigarroa,* MD, FACC, FSCAI Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon 97201
New procedures are often accompanied by a “learning curve,” which refers to the fact that an operator and their support staff may have more difficulties in patient selection and the performance of a procedure. Learning curves often translate into higher complication rates, at the initiation of a new procedure, but with experience, the difficulties will decrease to a certain baseline complication level. The learning curve creates a dilemma for both patients and operators—a reasonable patient does not want to be the first to have a new procedure, especially if there are alternatives, and the operator is put in a classic bind, needing to recruit patients for the new procedure, but knowing that the risk of being one of the first patients is often higher than that of a later patients. The article by Cruz-Gonzalez et al. [1] in this month’s journal looks at their single center experience with the Amplatzer Cardiac Plug (ACP) and the Watchman left atrial appendage occluder devices. Although the numbers are small, they demonstrate a high early complication rate (3/10 patients) followed by a dramatic drop (0/21 patients). The novel aspect of their paper is the comparison of the ACP to the Watchman. The early group was comprised of the first 10 ACP patients, and these were compared to 11 later ACP patients and the first 10 Watchman patients. The authors conclude that there was overlap in the learning curve for the ACP and Watchman procedures, and attribute the lack of complications in the first 10 Watchman patients to this. Again, the numbers are very small, making it quite difficult to draw conclusions. In the three major studies of the Watchman device, PROTECT AF, the continuing access protocol (CAP), and PREVAIL, clearer conclusions can be drawn. PROTECT AF [2], was the first randomized trial of the Watchman, taking patients with a CHADS2 score of 1 or high and randomizing 2:1 to Watchman vs. warfarin. A total of 592 patients underwent attempted Watchman placement. After PROTECT was closed, C 2014 Wiley Periodicals, Inc. V
study sites still had access to the device under CAP, and another 460 were implanted. Then, the PREVAIL study was started, for patients with a CHADS2 score of 2 or higher, again randomized 2:1 to Watchman. Interesting aspects of the learning curve emerge [2]. In the first half of the PROTECT AF trial, the complication rate was 10.0% which dropped to 5.5% for the second half of PROTECT. In CAP and PREVAIL, the complication rates were 3.7 and 4.2%, respectively. Recent data regarding PREVAIL was presented at a FDA panel and revealed no difference in complication rates between the experienced operators (who had been part of PROTECT and CAP) and new operators (who started placing the Watchman in PREVAIL). The most likely explanation for this is the implementation of extensive mandatory training for new sites and new operators in PREVAIL. Following identification of new sites, the training includes extensive online training, an examination, in person training, proctoring by company personnel or experienced physicians, and ongoing case support by industry personnel. Impressively, by the PREVAIL data, this approach seems to have worked. The Cruz-Gonzalez paper hints at another method for shifting the learning curve [1]. There is an implication (although the numbers are very small) that the learning curve for the ACP can substitute for the learning curve for the Watchman. There is certainly some logic to this, as they are similar devices and access and deployment are similar. The main dangers in both of these devices are the transseptal puncture and manipulating the device in the thin-walled left atrial appendage. Although all new operators should go through the required training, those with experience using similar devices would likely achieve independence earlier than an operator without such experience. Conflict of Interest: Nothing to report. *Correspondence to: Joaquin E. Cigarroa, MD, Knight Cardiovascular Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, UHN 62, Portland, OR 97201. E-mail: [email protected] Received 7 January 2014; Revision accepted 12 January 2014 DOI: 10.1002/ccd.25400 Published online 24 February 2014 in Wiley Online Library (wileyonlinelibrary.com)
648
Henrikson and Cigarroa
As operators, we all have a responsibility to patients to try to minimize the learning curve as much as possible, ideally shifting the learning curve to preclinical models or simulators. As demonstrated by Watchman, proficiency in coronary and electrophysiology procedures does not translate into low complication rates in structural left appendage work. For our patients, we must ensure comprehensive training by physicians and industry, often incorporating specific aspects including an understanding of equipment design, anatomic variation, procedural components, and where feasible simulation training and proctoring. Experience in
PROTECT AF, CAP, and PREVAIL trials demonstrate this is possible and beneficial. REFERENCES 1. Cruz-Gonzalez I, Perez-Rivera A, Lopez-Jimenez R, et al. Significance of the learning curve in left atrial appendage occlusion with two different devices. Catheter Cardiovasc Interv 2014;83:642–646. 2. Reddy VY, Holomes D, Doshi SK, et al. Safety of percutaneous left atrial appendage closure: Results from the Watchman left atrial appendage system for embolic protection in patients with AF (PROTECT AF) clinical trial and the continued access registry. Circulation 2011;123:417–424.
Catheterization and Cardiovascular Interventions DOI 10.1002/ccd. Published on behalf of The Society for Cardiovascular Angiography and Interventions (SCAI).
