ORIGINAL ARTICLE
Cost-Benefit Analysis of Robotic Versus Nonrobotic Minimally Invasive Mitral Valve Surgery Mohammed Hassan, MD,* Yongjie Miao, MS,Þ Joy Lincoln, PhD,Þ and Marco Ricci, MD*
Objective: To date, a direct comparison of minimally invasive mitral valve repair or replacement (mini-MVR) versus robotic MVR is lacking; therefore, the purpose of this study was to address this deficit and compare mini-MVR with robotic MVR from a cost-benefit perspective. Methods: From a total of 759 literature citations, 21 studies were included for statistical comparisons of benefit outcomes, whereas 3 studies and our institutional experience were used to compare costs. Results: The total cost per case exceeding that of conventional MVR is approximately $2063.90 for robotic MVR and $271 for mini-MVR. Mean 30-day mortality rates for mini-MVR and robotic MVR groups were 1.24% and 0.55%, respectively [106/8548 vs 6/1089; odds ratio (OR), 2.27; P = 0.052]. The conversion rate to conventional MVR was 0.77% in mini-MVR and 1.83% in robotic MVR (35/5092 vs 22/1046; OR, 0.32; P G 0.001). The rate of neurologic events was 1.32% in mini-MVR and 2.37% in robotic MVR (109/8257 vs 20/845; OR, 0.55; P = 0.02). Postoperative atrial fibrillation was seen in 11.42% of mini-MVR patients and in 19.67% of robotic MVR patients (371/3249 vs 203/1032; OR, 0.53, P G 0.001). Mean cardiopulmonary bypass time was longer in mini-MVR (137.4 vs 130.4 minutes), whereas cross-clamp time was shorter (82.2 vs 96.7 minutes). Conclusions: Our comparative analysis provides insights into the clinical benefits versus variable costs relationship related to mini-MVR and robotic MVR.
operations performed through a sternotomy approach. Minimally invasive (nonrobotic) mitral valve surgery can be performed using a variety of approaches including a right minithoracotomy, a right vertical minithoracotomy, or an upper or lower hemisternotomy using special instrumentation and direct or thoracoscopic assisted visualization. The major advantages of mini-MVR as compared with conventional MVR include reduced intraoperative bleeding and postoperative pain, decreased transfusion requirements, and reduced length of stay (LOS), thereby making this an attractive alternative to conventional MVR.1 Similarly, robotic MVR also results in reduced length of hospital stay, transfusion requirements, and analgesic requirement.2 Robotic technology provides enhanced surgical precision, visualization, and accuracy as well as improved threedimensional magnification and ergonomics. The learning curve involved with both techniques is not insignificant.3 In recent years, several studies have compared the benefits of mini-MVR with those of conventional MVR via sternotomy and included limited cost analyses.4 Similar cost comparisons have been made for robotic MVR versus conventional MVR.5,6 However, to date, a comparative analysis of mini-MVR versus robotic MVR is lacking. Herein, we present a comparative analysis of mini-MVR versus robotic MVR to determine how these two surgical approaches differ from an in-hospital cost-benefit perspective.
Key Words: Minimally invasive surgery, Mitral valve surgery, Robotics, Cost-benefit analysis. (Innovations 2015;10:90Y95)
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inimally invasive mitral valve repair or replacement (mini-MVR) and robotic MVR have recently emerged as less invasive alternatives to conventional mitral valve Accepted for publication December 31, 2014. From the *Division of Cardiothoracic Surgery, Department of Surgery, University of New Mexico, Albuquerque, NM USA; and †Center for Cardiovascular and Pulmonary Research, Nationwide Children’s Hospital Research Institute, Department of Pediatrics, The Ohio State University, Columbus, OH USA. Disclosures: Marco Ricci, MD, is a consultant to MAQUET, Wayne, NJ USA. Mohammed Hassan, MD, Yongjie Miao, MS, and Joy Lincoln, PhD, declare no conflicts of interest. Address correspondence and reprints requests to Mohammed Hassan, MD, Division of Cardiothoracic Surgery, University of New Mexico, 1 University of New Mexico, Albuquerque, NM 87131Y0001 USA. E-mail: [email protected]. Copyright * 2015 by the International Society for Minimally Invasive Cardiothoracic Surgery ISSN: 1556-9845/15/1002-0090
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PATIENTS AND METHODS The search was conducted using PubMed in May 2013. Our analysis was performed by using two sets of studies from the available literature: (a) one data set to compare mini-MVR and robotic MVR with conventional MVR via sternotomy with respect to clinical benefits; (b) a second data set to compare mini-MVR and robotic MVR with conventional MVR via sternotomy with respect to in-hospital costs. Inclusion criteria included the following: (1) the patient population underwent mitral valve repair or replacement; (2) there was a comparison of outcomes between mini-MVR and conventional MVR via sternotomy or between robotic MVR and conventional MVR; and (3) the study reported 30-day mortality. We included the largest studies with the most complete set of data, while avoiding studies with potential repetition. Meta-analyses and studies where the data had been previously reported were excluded. Cost analysis used data from the literature as well as our institutional experience.
Clinical Benefit Analysis The variables analyzed included total number of patients, age, mortality, central nervous system event (stroke or transient Innovations & Volume 10, Number 2, March/April 2015
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TABLE 1. Efficacy Studies Study, Year, Reference Iribarne McClure Vanermen Torracca Aybek Pfanmuller D’Alfonso El-Fiky Grossi Seeburger Murzi Svensson Goldstone Chitwood Folliguet Murphy Tatooles Bhamidipati Cheng Jones Mihaljevic
Period
No. Patients
Approach
2000Y2008 1996Y2011 1997Y2000 1999Y2003 1997Y2004 1999Y2010 1999Y2010 N/A 1995Y2007 1999Y2007 2003Y2011 1995Y2004 2002Y2011 2000Y2006 2004Y2005 N/A 2001Y2002 2004Y2008 2005Y2009 2003Y2004 2007Y2010
382 1000 175 104 241 180 179 50 1282 1339 936 2124 556 309 25 201 25 43 120 32 334
Minimally invasive Minimally invasive Minimally invasive Minimally invasive Minimally invasive Minimally invasive Minimally invasive Minimally invasive Minimally invasive Minimally invasive Minimally invasive Minimally invasive Minimally invasive Robotic assisted Robotic assisted Robotic assisted Robotic assisted Robotic assisted Robotic assisted Robotic assisted Robotic assisted
ischemic attack), atrial fibrillation, wound infection, conversions sternotomy from the initial intended approach, cardiopulmonary bypass (CPB) time, cross-clamp time, LOS, ejection fraction, number of repairs, and number of concomitant procedures.
Cost Analysis Assumptions Three articles were identified for the in-hospital cost analysis. Two of the three studies came from the same institution; however, one addressed robotic costs and the other addressed minimally invasive nonrobotic costs. For mini-MVR and robotic MVR, cost data were presented as added cost of the procedure as compared with conventional MVR. Because the robot is now a common part of the operating room inventory and there is great variability across hospitals in the services using the robot, we excluded the fixed cost component of using the robot and only considered variable costs made up of disposables. Similarly, the fixed cost of the minimally invasive instrument set was excluded from the calculation. Variable costs were estimated as the cost per case of mini-MVR or robotic MVR in excess of conventional MVR cost.
Statistical Analysis Fixed models were used to calculate the mean, SE, and 95% confidence intervals using the weighted method for each of the continuous variables under each treatment. W2 test was used for categorical data. The SE, odds ratio (OR), and the 95% TABLE 2. Cost Studies Study, Year, Reference Iribarne Kam Morgan
Period
No. Patients
Approach
2003Y2008 2005Y2008 N/A
217 107 10
Minimally invasive Robotic assisted Robotic assisted
Cost-Benefit in Mitral Valve Surgery
confidence intervals (CIs) were calculated. For continuous variables, if CIs overlapped, there was no significant difference between the two treatments; otherwise, we considered there to be evidence of a difference. A P value of less than 0.05 was considered statistically significant.
RESULTS Study Selection A total of 759 literature citations were identified, 21 were used to compare outcome measures, and 3 were used to compare costs using the study selection criteria described in the Patients and Methods section.1Y24 Of the 21 clinical studies, 13 compared mini-MVR with conventional MVR, whereas 8 compared robotic MVR with conventional MVR (Table 1). A total of 8548 patients were included in the mini-MVR group and 1089 in the robotic MVR group. Only three studies and our institutional data were used to examine the in-hospital costs of mini-MVR and robotic MVR (Table 2).
Benefit Analysis Results The summary of the statistical analysis is presented in Tables 3 and 4. The mini-MVR cohort included 8548, whereas the robotic MVR cohort included 1089 patients. In analyzing the continuous variables, the differences noted were based on comparing the 95% CIs between surgical approaches. In the study population, the mean age for mini-MVR patients was 57.8 years (95% CI, 57.7Y57.82), and for robotic MVR patients, it was 56.6 years (95% CI, 55.88Y57.26). The 30-day mean mortality rate was 1.24% and 0.55% in the mini-MVR and robotic MVR groups, respectively (OR, 2.27; P = 0.052). The conversion rate to conventional MVR was 0.77% in the mini-MVR group and 1.83% in the robotic MVR group (OR, 0.32; P G 0.001). Mean CPB time was similar in the two groups (137.4 minutes in the mini-MVR vs 130.4 minutes in the robotic MVR group), as was cross-clamp time (82.2 minutes in the mini-MVR vs
TABLE 3. Continuous Variables Variable Age Mini-MVR Robotic MVR Ejection fraction Mini-MVR Robotic MVR CPB Mini-MVR Robotic MVR Cross-clamp Mini-MVR Robotic MVR LOS Mini-MVR Robotic MVR
Mean
SE
Lower Limit
Upper Limit
57.76 56.57
0.029 0.355
57.7 55.88
57.82 57.26
52.12 58.79
0.02 0.296
52.08 58.20
52.16 59.36
137.37 130.38
0.129 1.15
137.12 128.13
137.62 132.65
82.24 96.686
0.093 0.902
82.06 94.92
82.42 98.45
7.78 5.545
0.019 0.193
7.75 5.167
7.82 5.923
CPB indicates cardiopulmonary bypass; LOS, length of stay; mini-MVR, minimally invasive mitral valve repair or replacement; MVR, mitral valve repair or replacement.
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TABLE 4. Categorical Variables Variable
Mini-MVR Events
Mini-MVR Total n
Robotic MVR Events
Robotic MVR Total n
OR
P
109 371 106 20 35 5381 1192
8257 3249 8548 4188 5092 8548 7162
20 203 6 3 22 886 218
845 1032 1089 820 1046 888 888
0.5518 0.526 2.266 1.306 0.322145 3.84E-03 0.6136
1.57E-02 2.11E-11 0.0519 0.666 3.62E-05 4.00E-15 6.59E-09
Stroke Atrial fibrillation Mortality Infection Conversion Repair Concomitant procedures
Mini-MVR indicates minimally invasive mitral valve repair or replacement; MVR, mitral valve repair or replacement; OR, odds ratio.
96.7 minutes in the robotic MVR group). The LOS was longer in the mini-MVR group (7.8 days vs 5.5 days). When examining the categorical variables, the mortality rate was 1.24% in the mini-MVR group and 0.55% in the robotic MVR group (OR, 2.266; P = 0.0519). Mitral valve repair was performed in 73.5% of the mini-MVR operations, whereas it was performed in 99.7% of the robotic MVR surgeries (OR, 0.003; P G 0.001). Concomitant procedures, including ablation for atrial fibrillation and tricuspid valve surgery, were performed in 16.6% of the mini-MVR patients and in 23.4% of the robotic MVR patients (OR, 0.61; P G 0.001). The rate of neurologic events was 1.3% in the miniMVR group and 2.3% in the robotic MVR group (OR, 0.55; P = 0.02). Atrial fibrillation was seen in 11.4% of the miniMVR patients and in 19.6% of the robotic MVR patients (OR, 0.53; P G 0.001). The rate of wound infection was 0.4% in the mini-MVR group and 0.6% in the robotic MVR group (OR, 1.3; P = 0.67). The conversion rate (to thoracotomy or sternotomy) from the originally intended minimally invasive surgery was 0.7% in the mini-MVR group and 1.8% in the robotic MVR group (OR, 0.32; P G 0.001).
Cost Analysis Results We found one study that analyzed costs associated with mini-MVR and two studies that analyzed costs with robotic MVR. The mean variable added cost of robotic MVR over conventional MVR was estimated at $2063.90 per case, resulting in a total variable cost of $515,975.00 during a 5-year period over conventional MVR assuming 50 cases per year and $1,031,950.00 assuming 100 cases per year (Table 5, Fig. 1A). For mini-MVR, the estimated variable cost per case in excess of conventional MVR cost was $79.4 This value from the article of Iribarne et al assumed central aortic cannulation. Based on our institutional data, we added the net excess cost of
using a peripheral arterial cannula ($305) and subtracted the cost of a central aortic cannula ($34), for a total excess variable cost of $271.00 per case. This totaled $67,750.00 and $135,500.00 during a 5-year period over conventional MVR assuming 50 cases per year and 100 cases per year, respectively (Table 5, Fig. 1A). The mean LOS for the mini-MVR group was 7.7 days (95% CI, 7.75Y7.82), whereas that for the robotic MVR group was 5.5 days (95% CI, 5.17Y5.92). The daily hospital cost was estimated at $368.67.6
Comment Minimally invasive mitral valve operations, with or without the use of robotic technology, have increased from 11.9% to 20.1% of total mitral valve operations between 2004 and 2008.25 These minimally invasive options have been shown to offer benefits to patients compared with conventional MVR with reduced pain, transfusion requirement, and a shorter hospital stay.6 Although the use of robotic surgery has become a tool in the marketing of sophisticated surgical services, the associated costs are not insignificant.3 In the United States, reimbursement rates for mini-MVR or robotic MVR do not differ from those of conventional MVR, although this may be different in other countries. Robotic MVR has been compared with conventional MVR but not with nonrobotic mini-MVR. Our analysis aimed to shed light on the relative in-hospital cost-benefit profiles of these two approaches. During the training phase, the learning curve for robotic or minimally invasive operations can be steep,25 but the initial costs of training surgeons and staff are difficult to quantify and were not included in our analysis. Our analysis suggests that mini-MVR had a lower conversion rate to sternotomy. In terms of clinical benefits, the mortality rate in the mini-MVR group approached statistical
TABLE 5. Costs of Mini-MVR and Robotic MVR in Excess of Conventional MVR Cost Excess cost per case (variable cost) 5-y hospital costs (50 cases annually) 5-y hospital costs (100 cases annually)
Mean Excess Cost in Mini-MVR
Mean Excess Cost in Robotic MVR
$350.00 $67,750.00 $135,500.00
$2,063.90* $515,975.00 $1,031,950.00
*Based on mean costs of two studies: $2635.80 + $1492.00 / 2 = $2063.90. Mini-MVR indicates minimally invasive mitral valve repair or replacement; MVR, mitral valve repair or replacement.
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FIGURE 1. A, Cost of mini-MVR and robotic MVR in excess of conventional MVR cost assuming 100 cases per year. B, Map of estimated values (benefit/cost) of different surgical approaches. Mini-MVR indicates minimally invasive mitral valve repair or replacement; MVR, mitral valve repair or replacement.
significance. The mini-MVR group included slightly older patients with a lower preoperative ejection fraction. As the patient populations of both groups were not matched for preoperative risk factors, care should be taken when interpreting data related to the relative risk of mortality for each surgical approach. A future prospective randomized trial would be better suited to address this question. Although the rates of stroke and atrial fibrillation were lower in the mini-MVR patients, there was no significant difference in the rate of infection between the two approaches. Considered collectively, these clinical outcome profiles suggest that, from a clinical benefit perspective, both approaches seem to offer comparable clinical benefits. The robotic MVR group had a higher proportion of reported valve repairs (73.5% vs 99.7%). The goal of the article was not to compare repair rates of both approaches because the data reported did not specify the ‘‘intent to repair.’’ It is therefore difficult to make conclusions about comparing the ability to repair or replace based on the data used. The decision when to use mini-MVR or robotic MVR with regard to the intent to repair likely varies between institutions. However, the high repair rate using robotic MVR is consistent with the superior capabilities offered by the robot such as enhanced valve
visualization and surgical precision. Similarly, the rate of success in achieving a valve repair using the mini-MVR approach has been reported with excellent results.25 Some may also elect to replace the valve robotically because this approach has been reported with success.26 With respect to procedural costs, we estimated the added costs (variable costs) in excess of conventional MVR. Our analysis revealed that the total in-hospital cost added by miniMVR to conventional MVR was $271.00 per case (assuming peripheral cannulation) versus $2063.90 per case for robotic MVR. This translated into a total added cost to the hospital of $67,750 during a 5-year period for a mini-MVR program versus a cost of $515,975.00 for a robotic MVR program, if performing 50 cases per year (Table 5). When assuming 100 cases per year, the total in-hospital costs in 5 years would amount to $135,500.00 for a mini-MVR program versus $1,031,950.00 for a robotic MVR program (Table 5, Fig. 1A). With respect to the LOS, we are uncertain that the longer LOS noted in mini-MVR group versus robotic MVR is clinically meaningful, in light of the fact that in all US studies, the LOS for the two procedures was comparable. The difference was entirely caused by the effect of one isolated European report7 in which the LOS for mini-MVR was
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considerably longer (mean, 12.4 days) than that of any other contemporary report. Nonetheless, both approaches have been associated with a shorter LOS when compared with the conventional approach. Because there is great variety between hospitals and across countries in discharge policies, the effect of the clinical outcome parameters examined on costs related to intensive care unit or total LOS is difficult to ascertain. Should the longer LOS in mini-MVR be confirmed by larger studies, we acknowledge that this difference could also impact LOS-related costs. Our study provides an in-hospital cost-benefit model for the mini-MVR versus robotic MVR approach that is likely applicable to the majority of health care environments, taking into account the current mitral valve surgery institutional volumes in the United States.27 Taken together, from a health care economic perspective, mini-MVR potentially provides comparable benefits at reduced operating costs (Fig. 1B). We acknowledge that our study has several important limitations. Retrospective multicenter analyses have inherent biases. Our study included data from centers not only in the United States but also outside the United States. Different patient management policies and reimbursement models could affect length of hospital stay. Fixed costs were not analyzed for both approaches as already mentioned. Other immeasurable factors that could alter the cost-benefit equation, including the learning curve, and marketing value of robotics were not analyzed. Moreover, the level of experience of the different centers from which data were obtained was difficult to quantify. However, the smallest study for robotic MVR included 50 patients, whereas that for mini-MVR reported 25 patients. We realize that the level of experience with mini-MVR or robotic MVR could also affect the observed outcomes. Lastly, the potential impact of LOS differences on costs was discussed earlier. Despite the limitations noted earlier, our comparative analysis provides insights into the clinical benefits versus variable costs relationship related to mini-MVR and robotic MVR. Although institution-specific variables may affect this relationship, health care organizations may take these costbenefit profiles into consideration when making strategic decisions in relation to cardiovascular service line development.
REFERENCES 1. McClure RS, Athanasopoulos LV, McGurk S, Davidson MJ, Couper GS, Cohn LH. One thousand minimally invasive mitral valve operations: early outcomes, late outcomes, and echocardiographic follow-up. J Thorac Cardiovasc Surg. 2013;145:1199Y1206. 2. Mihaljevic T, Pattakos G, Gillinov AM, et al. Robotic posterior mitral leaflet repair: neochordal versus resectional techniques. Ann Thorac Surg. 2013;95:787Y794. 3. Chitwood W Jr, Rodriguez E, Chu MW, et al. Robotic mitral valve repairs in 300 patients: a single-center experience. J Thorac Cardiovasc Surg. 2008;136:436Y441. 4. Iribarne A, Easterwood R, Russo MJ, et al. A minimally invasive approach is more cost-effective than a traditional sternotomy approach for mitral valve surgery. J Thorac Cardiovasc Surg. 2011;142:1507Y1514. 5. Morgan JA, Thornton BA, Peacock JC, et al. Does robotic technology make minimally invasive cardiac surgery too expensive? A hospital cost analysis of robotic and conventional techniques. J Card Surg. 2005;20: 246Y251.
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6. Kam J, Cooray SD, Kam JK, Smith JA, Almeida AA. A cost-analysis study of robotic versus conventional mitral valve repair. Heart Lung Circ. 2010;19:413Y418. 7. Seeburger J, Borger MA, Falk V, et al. Minimal invasive mitral valve repair for mitral regurgitation: results of 1339 consecutive patients. Eur J Cardiothorac Surg. 2008;34:760Y765. 8. Bhamidipati CM, Mehta GS, Sarwar MF, Sooppan R, Dilip KA, Lutz CJ. Robot-assisted mitral valve repair: a single institution review. Innovations. 2010;5:295Y299. 9. Iribarne A, Russo M, Easterwood R, et al. Minimally invasive versus sternotomy approach for mitral valve surgery: a propensity analysis. Ann Thorac Surg. 2010;90:1471Y1478. 10. Tatooles AJ, Pappas PS, Gordon PJ, Slaughter MS. Minimally invasive mitral valve repair using the da Vinci robotic system. Ann Thorac Surg. 2004;77:1978Y1982. 11. Folliguet T, Vanhuyse F, Constantino X, Realli M, Laborde F. Mitral valve repair robotic versus sternotomy. Eur J Cardiothorac Surg. 2006;29: 362Y366. 12. Murphy D, Smith JM, Siwek L, et al. Multicenter mitral valve study: a lateral approach using the da Vinci surgical system. Innovations. 2007;2:56Y61. 13. Svensson LG, Atik FA, Cosgrove DM, et al. Minimally invasive versus conventional mitral valve surgery: a propensity-matched comparison. J Thorac Cardiovasc Surg. 2010;139:926Y932. 14. Schroeyers P, Wellens F, De Geest R, et al. Minimally invasive video-assisted mitral valve surgery: our lessons after a 4-year experience. Ann Thorac Surg. 2001;72:S1050YS1054. 15. Torracca L, Lapenna E, De Bonis M, et al. Minimally invasive mitral valve repair as a routine approach in selected patients. J Cardiovasc Med (Hagerstown). 2006;7:57Y60. 16. Aybek T, Dogan S, Risteski PS, et al. Two hundred forty minimally invasive mitral operations through right minithoracotomy. Ann Thorac Surg. 2006;81:1618Y1624. 17. Pfannmu¨ller B, Seeburger J, Misfeld M, Borger MA, Garbade J, Mohr FW. Minimally invasive mitral valve repair for anterior leaflet prolapse. J Thorac Cardiovasc Surg. 2013;146:109Y113. 18. D’Alfonso A, Capestro F, Zingaro C, Matteucci S, Rescigno G, Torracca L. Ten years’ follow-up of single-surgeon minimally invasive reparative surgery for degenerative mitral valve disease. Innovations. 2012;7: 270Y273. 19. El-Fiky MM, El-Sayegh T, El-Beishry AS, et al. Limited right anterolateral thoracotomy for mitral valve surgery. Eur J Cardiothorac Surg. 2000;17: 710Y713. 20. Grossi EA, Loulmet DF, Schwartz CF, et al. Evolution of operative techniques and perfusion strategies for minimally invasive mitral valve repair. J Thorac Cardiovasc Surg. 2012;143:S68YS70. 21. Murzi M, Cerillo AG, Bevilacqua S, et al. Enhancing departmental quality control in minimally invasive mitral valve surgery: a single-institution experience. Eur J Cardiothorac Surg. 2012;42:500Y506. 22. Goldstone AB, Atluri P, Szeto WY, et al. Minimally invasive approach provides at least equivalent results for surgical correction of mitral regurgitation: a propensity-matched comparison. J Thorac Cardiovasc Surg. 2013;145:748Y756. 23. Cheng W, Fontana GP, De Robertis MA, et al. Is robotic mitral valve repair a reproducible approach? J Thorac Cardiovasc Surg. 2010;139:628Y633. 24. Jones BA, Krueger S, Howell D, Meinecke B, Dunn S. Robotic mitral valve repair: a community hospital experience. Tex Heart Inst J. 2005;32: 143Y146. 25. Gammie JS, Zhao Y, Peterson ED, O’Brien SM, Rankin JS, Griffith BP. Less-invasive mitral valve operations: trends and outcomes from The Society of Thoracic Surgeons Adult Cardiac Surgery Database. Ann Thorac Surg. 2010;90:1401Y1410. 26. Gao C, Yang M, Xiao C, et al. Robotically assisted mitral valve replacement. Thorac Cardiovasc Surg. 2012;143:S64YS67. 27. Kilic A, Shah A, Conte J, Baumgartner WA, Yuh DD. Operative outcomes in mitral valve surgery: Combined effect of surgeon and hospital volume in a population-based analysis. J Thorac Cardiovasc Surg. 2013;146: 638Y646.
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Cost-Benefit in Mitral Valve Surgery
CLINICAL PERSPECTIVE This cost-benefit analysis of robotic versus nonrobotic minimally invasive mitral valve surgery (mini-MVR) from Dr Hassan and his colleagues is an excellent contribution. To look at clinical benefit, they examined 21 studies involving more than 9600 patients. Thirteen studies compared mini-MVR with conventional MVR, whereas the others compared robotic MVR with conventional approaches. The cost analysis examined three studies that included only 334 patients and their own institutional experience. They concluded that there seemed to be both a clinical and a cost benefit to minimally invasive as opposed to robotic MVR. In terms of clinical benefit, there was a significantly higher rate of stroke, atrial fibrillation, and conversion to conventional sternotomy in the robotic patients. There was a higher percentage of repairs in the robotic versus the mini-MVR group. However, this was likely due to the individual institutional experiences. In terms of cost, there was a distinct advantage to the mini-MVR over the robotic MVR group. The excess cost per case was $350 for the mini-MVR patients and $2064 for the robotic patients. This is an important study, and these analyses are extremely valuable when assessing new technology. Any new technology must provide clinical value. Value is defined as quality divided by cost. With the excess cost of robotic valve surgery when compared to mini-MVR, one would have to see a distinct clinical benefit to provide similar value. In this literature review, the clinical value of robotic technology is clearly less than that for mini-MVR. There are limitations to the study. These are all retrospective multicenter analyses and subject to inherent biases. Moreover, they included data from both inside and outside of the United States. Their cost data were based on a relatively small number of patients, and they did not look at fixed costs, only variable costs. Moreover, it was difficult to define the level of experience of the different centers, and a number of the studies had only a small number of patients. However, the authors are to be congratulated for performing this analysis. It is provocative and suggests that robotic valve surgery does not provide clinical value when compared with a nonrobotic minimally invasive approach. However, this hypothesis would need to be tested in larger prospective trials or ideally in a randomized, multicenter approach. It is unlikely that this will ever be performed because of the inherent prejudices of many centers. In the meantime, this review provides food for thought.
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Cost-Benefit Analysis of Robotic Versus Nonrobotic Minimally Invasive Mitral Valve Surgery Mohammed Hassan, MD,* Yongjie Miao, MS,Þ Joy Lincoln, PhD,Þ and Marco Ricci, MD*
Objective: To date, a direct comparison of minimally invasive mitral valve repair or replacement (mini-MVR) versus robotic MVR is lacking; therefore, the purpose of this study was to address this deficit and compare mini-MVR with robotic MVR from a cost-benefit perspective. Methods: From a total of 759 literature citations, 21 studies were included for statistical comparisons of benefit outcomes, whereas 3 studies and our institutional experience were used to compare costs. Results: The total cost per case exceeding that of conventional MVR is approximately $2063.90 for robotic MVR and $271 for mini-MVR. Mean 30-day mortality rates for mini-MVR and robotic MVR groups were 1.24% and 0.55%, respectively [106/8548 vs 6/1089; odds ratio (OR), 2.27; P = 0.052]. The conversion rate to conventional MVR was 0.77% in mini-MVR and 1.83% in robotic MVR (35/5092 vs 22/1046; OR, 0.32; P G 0.001). The rate of neurologic events was 1.32% in mini-MVR and 2.37% in robotic MVR (109/8257 vs 20/845; OR, 0.55; P = 0.02). Postoperative atrial fibrillation was seen in 11.42% of mini-MVR patients and in 19.67% of robotic MVR patients (371/3249 vs 203/1032; OR, 0.53, P G 0.001). Mean cardiopulmonary bypass time was longer in mini-MVR (137.4 vs 130.4 minutes), whereas cross-clamp time was shorter (82.2 vs 96.7 minutes). Conclusions: Our comparative analysis provides insights into the clinical benefits versus variable costs relationship related to mini-MVR and robotic MVR.
operations performed through a sternotomy approach. Minimally invasive (nonrobotic) mitral valve surgery can be performed using a variety of approaches including a right minithoracotomy, a right vertical minithoracotomy, or an upper or lower hemisternotomy using special instrumentation and direct or thoracoscopic assisted visualization. The major advantages of mini-MVR as compared with conventional MVR include reduced intraoperative bleeding and postoperative pain, decreased transfusion requirements, and reduced length of stay (LOS), thereby making this an attractive alternative to conventional MVR.1 Similarly, robotic MVR also results in reduced length of hospital stay, transfusion requirements, and analgesic requirement.2 Robotic technology provides enhanced surgical precision, visualization, and accuracy as well as improved threedimensional magnification and ergonomics. The learning curve involved with both techniques is not insignificant.3 In recent years, several studies have compared the benefits of mini-MVR with those of conventional MVR via sternotomy and included limited cost analyses.4 Similar cost comparisons have been made for robotic MVR versus conventional MVR.5,6 However, to date, a comparative analysis of mini-MVR versus robotic MVR is lacking. Herein, we present a comparative analysis of mini-MVR versus robotic MVR to determine how these two surgical approaches differ from an in-hospital cost-benefit perspective.
Key Words: Minimally invasive surgery, Mitral valve surgery, Robotics, Cost-benefit analysis. (Innovations 2015;10:90Y95)
M
inimally invasive mitral valve repair or replacement (mini-MVR) and robotic MVR have recently emerged as less invasive alternatives to conventional mitral valve Accepted for publication December 31, 2014. From the *Division of Cardiothoracic Surgery, Department of Surgery, University of New Mexico, Albuquerque, NM USA; and †Center for Cardiovascular and Pulmonary Research, Nationwide Children’s Hospital Research Institute, Department of Pediatrics, The Ohio State University, Columbus, OH USA. Disclosures: Marco Ricci, MD, is a consultant to MAQUET, Wayne, NJ USA. Mohammed Hassan, MD, Yongjie Miao, MS, and Joy Lincoln, PhD, declare no conflicts of interest. Address correspondence and reprints requests to Mohammed Hassan, MD, Division of Cardiothoracic Surgery, University of New Mexico, 1 University of New Mexico, Albuquerque, NM 87131Y0001 USA. E-mail: [email protected]. Copyright * 2015 by the International Society for Minimally Invasive Cardiothoracic Surgery ISSN: 1556-9845/15/1002-0090
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PATIENTS AND METHODS The search was conducted using PubMed in May 2013. Our analysis was performed by using two sets of studies from the available literature: (a) one data set to compare mini-MVR and robotic MVR with conventional MVR via sternotomy with respect to clinical benefits; (b) a second data set to compare mini-MVR and robotic MVR with conventional MVR via sternotomy with respect to in-hospital costs. Inclusion criteria included the following: (1) the patient population underwent mitral valve repair or replacement; (2) there was a comparison of outcomes between mini-MVR and conventional MVR via sternotomy or between robotic MVR and conventional MVR; and (3) the study reported 30-day mortality. We included the largest studies with the most complete set of data, while avoiding studies with potential repetition. Meta-analyses and studies where the data had been previously reported were excluded. Cost analysis used data from the literature as well as our institutional experience.
Clinical Benefit Analysis The variables analyzed included total number of patients, age, mortality, central nervous system event (stroke or transient Innovations & Volume 10, Number 2, March/April 2015
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Innovations & Volume 10, Number 2, March/April 2015
TABLE 1. Efficacy Studies Study, Year, Reference Iribarne McClure Vanermen Torracca Aybek Pfanmuller D’Alfonso El-Fiky Grossi Seeburger Murzi Svensson Goldstone Chitwood Folliguet Murphy Tatooles Bhamidipati Cheng Jones Mihaljevic
Period
No. Patients
Approach
2000Y2008 1996Y2011 1997Y2000 1999Y2003 1997Y2004 1999Y2010 1999Y2010 N/A 1995Y2007 1999Y2007 2003Y2011 1995Y2004 2002Y2011 2000Y2006 2004Y2005 N/A 2001Y2002 2004Y2008 2005Y2009 2003Y2004 2007Y2010
382 1000 175 104 241 180 179 50 1282 1339 936 2124 556 309 25 201 25 43 120 32 334
Minimally invasive Minimally invasive Minimally invasive Minimally invasive Minimally invasive Minimally invasive Minimally invasive Minimally invasive Minimally invasive Minimally invasive Minimally invasive Minimally invasive Minimally invasive Robotic assisted Robotic assisted Robotic assisted Robotic assisted Robotic assisted Robotic assisted Robotic assisted Robotic assisted
ischemic attack), atrial fibrillation, wound infection, conversions sternotomy from the initial intended approach, cardiopulmonary bypass (CPB) time, cross-clamp time, LOS, ejection fraction, number of repairs, and number of concomitant procedures.
Cost Analysis Assumptions Three articles were identified for the in-hospital cost analysis. Two of the three studies came from the same institution; however, one addressed robotic costs and the other addressed minimally invasive nonrobotic costs. For mini-MVR and robotic MVR, cost data were presented as added cost of the procedure as compared with conventional MVR. Because the robot is now a common part of the operating room inventory and there is great variability across hospitals in the services using the robot, we excluded the fixed cost component of using the robot and only considered variable costs made up of disposables. Similarly, the fixed cost of the minimally invasive instrument set was excluded from the calculation. Variable costs were estimated as the cost per case of mini-MVR or robotic MVR in excess of conventional MVR cost.
Statistical Analysis Fixed models were used to calculate the mean, SE, and 95% confidence intervals using the weighted method for each of the continuous variables under each treatment. W2 test was used for categorical data. The SE, odds ratio (OR), and the 95% TABLE 2. Cost Studies Study, Year, Reference Iribarne Kam Morgan
Period
No. Patients
Approach
2003Y2008 2005Y2008 N/A
217 107 10
Minimally invasive Robotic assisted Robotic assisted
Cost-Benefit in Mitral Valve Surgery
confidence intervals (CIs) were calculated. For continuous variables, if CIs overlapped, there was no significant difference between the two treatments; otherwise, we considered there to be evidence of a difference. A P value of less than 0.05 was considered statistically significant.
RESULTS Study Selection A total of 759 literature citations were identified, 21 were used to compare outcome measures, and 3 were used to compare costs using the study selection criteria described in the Patients and Methods section.1Y24 Of the 21 clinical studies, 13 compared mini-MVR with conventional MVR, whereas 8 compared robotic MVR with conventional MVR (Table 1). A total of 8548 patients were included in the mini-MVR group and 1089 in the robotic MVR group. Only three studies and our institutional data were used to examine the in-hospital costs of mini-MVR and robotic MVR (Table 2).
Benefit Analysis Results The summary of the statistical analysis is presented in Tables 3 and 4. The mini-MVR cohort included 8548, whereas the robotic MVR cohort included 1089 patients. In analyzing the continuous variables, the differences noted were based on comparing the 95% CIs between surgical approaches. In the study population, the mean age for mini-MVR patients was 57.8 years (95% CI, 57.7Y57.82), and for robotic MVR patients, it was 56.6 years (95% CI, 55.88Y57.26). The 30-day mean mortality rate was 1.24% and 0.55% in the mini-MVR and robotic MVR groups, respectively (OR, 2.27; P = 0.052). The conversion rate to conventional MVR was 0.77% in the mini-MVR group and 1.83% in the robotic MVR group (OR, 0.32; P G 0.001). Mean CPB time was similar in the two groups (137.4 minutes in the mini-MVR vs 130.4 minutes in the robotic MVR group), as was cross-clamp time (82.2 minutes in the mini-MVR vs
TABLE 3. Continuous Variables Variable Age Mini-MVR Robotic MVR Ejection fraction Mini-MVR Robotic MVR CPB Mini-MVR Robotic MVR Cross-clamp Mini-MVR Robotic MVR LOS Mini-MVR Robotic MVR
Mean
SE
Lower Limit
Upper Limit
57.76 56.57
0.029 0.355
57.7 55.88
57.82 57.26
52.12 58.79
0.02 0.296
52.08 58.20
52.16 59.36
137.37 130.38
0.129 1.15
137.12 128.13
137.62 132.65
82.24 96.686
0.093 0.902
82.06 94.92
82.42 98.45
7.78 5.545
0.019 0.193
7.75 5.167
7.82 5.923
CPB indicates cardiopulmonary bypass; LOS, length of stay; mini-MVR, minimally invasive mitral valve repair or replacement; MVR, mitral valve repair or replacement.
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TABLE 4. Categorical Variables Variable
Mini-MVR Events
Mini-MVR Total n
Robotic MVR Events
Robotic MVR Total n
OR
P
109 371 106 20 35 5381 1192
8257 3249 8548 4188 5092 8548 7162
20 203 6 3 22 886 218
845 1032 1089 820 1046 888 888
0.5518 0.526 2.266 1.306 0.322145 3.84E-03 0.6136
1.57E-02 2.11E-11 0.0519 0.666 3.62E-05 4.00E-15 6.59E-09
Stroke Atrial fibrillation Mortality Infection Conversion Repair Concomitant procedures
Mini-MVR indicates minimally invasive mitral valve repair or replacement; MVR, mitral valve repair or replacement; OR, odds ratio.
96.7 minutes in the robotic MVR group). The LOS was longer in the mini-MVR group (7.8 days vs 5.5 days). When examining the categorical variables, the mortality rate was 1.24% in the mini-MVR group and 0.55% in the robotic MVR group (OR, 2.266; P = 0.0519). Mitral valve repair was performed in 73.5% of the mini-MVR operations, whereas it was performed in 99.7% of the robotic MVR surgeries (OR, 0.003; P G 0.001). Concomitant procedures, including ablation for atrial fibrillation and tricuspid valve surgery, were performed in 16.6% of the mini-MVR patients and in 23.4% of the robotic MVR patients (OR, 0.61; P G 0.001). The rate of neurologic events was 1.3% in the miniMVR group and 2.3% in the robotic MVR group (OR, 0.55; P = 0.02). Atrial fibrillation was seen in 11.4% of the miniMVR patients and in 19.6% of the robotic MVR patients (OR, 0.53; P G 0.001). The rate of wound infection was 0.4% in the mini-MVR group and 0.6% in the robotic MVR group (OR, 1.3; P = 0.67). The conversion rate (to thoracotomy or sternotomy) from the originally intended minimally invasive surgery was 0.7% in the mini-MVR group and 1.8% in the robotic MVR group (OR, 0.32; P G 0.001).
Cost Analysis Results We found one study that analyzed costs associated with mini-MVR and two studies that analyzed costs with robotic MVR. The mean variable added cost of robotic MVR over conventional MVR was estimated at $2063.90 per case, resulting in a total variable cost of $515,975.00 during a 5-year period over conventional MVR assuming 50 cases per year and $1,031,950.00 assuming 100 cases per year (Table 5, Fig. 1A). For mini-MVR, the estimated variable cost per case in excess of conventional MVR cost was $79.4 This value from the article of Iribarne et al assumed central aortic cannulation. Based on our institutional data, we added the net excess cost of
using a peripheral arterial cannula ($305) and subtracted the cost of a central aortic cannula ($34), for a total excess variable cost of $271.00 per case. This totaled $67,750.00 and $135,500.00 during a 5-year period over conventional MVR assuming 50 cases per year and 100 cases per year, respectively (Table 5, Fig. 1A). The mean LOS for the mini-MVR group was 7.7 days (95% CI, 7.75Y7.82), whereas that for the robotic MVR group was 5.5 days (95% CI, 5.17Y5.92). The daily hospital cost was estimated at $368.67.6
Comment Minimally invasive mitral valve operations, with or without the use of robotic technology, have increased from 11.9% to 20.1% of total mitral valve operations between 2004 and 2008.25 These minimally invasive options have been shown to offer benefits to patients compared with conventional MVR with reduced pain, transfusion requirement, and a shorter hospital stay.6 Although the use of robotic surgery has become a tool in the marketing of sophisticated surgical services, the associated costs are not insignificant.3 In the United States, reimbursement rates for mini-MVR or robotic MVR do not differ from those of conventional MVR, although this may be different in other countries. Robotic MVR has been compared with conventional MVR but not with nonrobotic mini-MVR. Our analysis aimed to shed light on the relative in-hospital cost-benefit profiles of these two approaches. During the training phase, the learning curve for robotic or minimally invasive operations can be steep,25 but the initial costs of training surgeons and staff are difficult to quantify and were not included in our analysis. Our analysis suggests that mini-MVR had a lower conversion rate to sternotomy. In terms of clinical benefits, the mortality rate in the mini-MVR group approached statistical
TABLE 5. Costs of Mini-MVR and Robotic MVR in Excess of Conventional MVR Cost Excess cost per case (variable cost) 5-y hospital costs (50 cases annually) 5-y hospital costs (100 cases annually)
Mean Excess Cost in Mini-MVR
Mean Excess Cost in Robotic MVR
$350.00 $67,750.00 $135,500.00
$2,063.90* $515,975.00 $1,031,950.00
*Based on mean costs of two studies: $2635.80 + $1492.00 / 2 = $2063.90. Mini-MVR indicates minimally invasive mitral valve repair or replacement; MVR, mitral valve repair or replacement.
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Cost-Benefit in Mitral Valve Surgery
FIGURE 1. A, Cost of mini-MVR and robotic MVR in excess of conventional MVR cost assuming 100 cases per year. B, Map of estimated values (benefit/cost) of different surgical approaches. Mini-MVR indicates minimally invasive mitral valve repair or replacement; MVR, mitral valve repair or replacement.
significance. The mini-MVR group included slightly older patients with a lower preoperative ejection fraction. As the patient populations of both groups were not matched for preoperative risk factors, care should be taken when interpreting data related to the relative risk of mortality for each surgical approach. A future prospective randomized trial would be better suited to address this question. Although the rates of stroke and atrial fibrillation were lower in the mini-MVR patients, there was no significant difference in the rate of infection between the two approaches. Considered collectively, these clinical outcome profiles suggest that, from a clinical benefit perspective, both approaches seem to offer comparable clinical benefits. The robotic MVR group had a higher proportion of reported valve repairs (73.5% vs 99.7%). The goal of the article was not to compare repair rates of both approaches because the data reported did not specify the ‘‘intent to repair.’’ It is therefore difficult to make conclusions about comparing the ability to repair or replace based on the data used. The decision when to use mini-MVR or robotic MVR with regard to the intent to repair likely varies between institutions. However, the high repair rate using robotic MVR is consistent with the superior capabilities offered by the robot such as enhanced valve
visualization and surgical precision. Similarly, the rate of success in achieving a valve repair using the mini-MVR approach has been reported with excellent results.25 Some may also elect to replace the valve robotically because this approach has been reported with success.26 With respect to procedural costs, we estimated the added costs (variable costs) in excess of conventional MVR. Our analysis revealed that the total in-hospital cost added by miniMVR to conventional MVR was $271.00 per case (assuming peripheral cannulation) versus $2063.90 per case for robotic MVR. This translated into a total added cost to the hospital of $67,750 during a 5-year period for a mini-MVR program versus a cost of $515,975.00 for a robotic MVR program, if performing 50 cases per year (Table 5). When assuming 100 cases per year, the total in-hospital costs in 5 years would amount to $135,500.00 for a mini-MVR program versus $1,031,950.00 for a robotic MVR program (Table 5, Fig. 1A). With respect to the LOS, we are uncertain that the longer LOS noted in mini-MVR group versus robotic MVR is clinically meaningful, in light of the fact that in all US studies, the LOS for the two procedures was comparable. The difference was entirely caused by the effect of one isolated European report7 in which the LOS for mini-MVR was
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considerably longer (mean, 12.4 days) than that of any other contemporary report. Nonetheless, both approaches have been associated with a shorter LOS when compared with the conventional approach. Because there is great variety between hospitals and across countries in discharge policies, the effect of the clinical outcome parameters examined on costs related to intensive care unit or total LOS is difficult to ascertain. Should the longer LOS in mini-MVR be confirmed by larger studies, we acknowledge that this difference could also impact LOS-related costs. Our study provides an in-hospital cost-benefit model for the mini-MVR versus robotic MVR approach that is likely applicable to the majority of health care environments, taking into account the current mitral valve surgery institutional volumes in the United States.27 Taken together, from a health care economic perspective, mini-MVR potentially provides comparable benefits at reduced operating costs (Fig. 1B). We acknowledge that our study has several important limitations. Retrospective multicenter analyses have inherent biases. Our study included data from centers not only in the United States but also outside the United States. Different patient management policies and reimbursement models could affect length of hospital stay. Fixed costs were not analyzed for both approaches as already mentioned. Other immeasurable factors that could alter the cost-benefit equation, including the learning curve, and marketing value of robotics were not analyzed. Moreover, the level of experience of the different centers from which data were obtained was difficult to quantify. However, the smallest study for robotic MVR included 50 patients, whereas that for mini-MVR reported 25 patients. We realize that the level of experience with mini-MVR or robotic MVR could also affect the observed outcomes. Lastly, the potential impact of LOS differences on costs was discussed earlier. Despite the limitations noted earlier, our comparative analysis provides insights into the clinical benefits versus variable costs relationship related to mini-MVR and robotic MVR. Although institution-specific variables may affect this relationship, health care organizations may take these costbenefit profiles into consideration when making strategic decisions in relation to cardiovascular service line development.
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6. Kam J, Cooray SD, Kam JK, Smith JA, Almeida AA. A cost-analysis study of robotic versus conventional mitral valve repair. Heart Lung Circ. 2010;19:413Y418. 7. Seeburger J, Borger MA, Falk V, et al. Minimal invasive mitral valve repair for mitral regurgitation: results of 1339 consecutive patients. Eur J Cardiothorac Surg. 2008;34:760Y765. 8. Bhamidipati CM, Mehta GS, Sarwar MF, Sooppan R, Dilip KA, Lutz CJ. Robot-assisted mitral valve repair: a single institution review. Innovations. 2010;5:295Y299. 9. Iribarne A, Russo M, Easterwood R, et al. Minimally invasive versus sternotomy approach for mitral valve surgery: a propensity analysis. Ann Thorac Surg. 2010;90:1471Y1478. 10. Tatooles AJ, Pappas PS, Gordon PJ, Slaughter MS. Minimally invasive mitral valve repair using the da Vinci robotic system. Ann Thorac Surg. 2004;77:1978Y1982. 11. Folliguet T, Vanhuyse F, Constantino X, Realli M, Laborde F. Mitral valve repair robotic versus sternotomy. Eur J Cardiothorac Surg. 2006;29: 362Y366. 12. Murphy D, Smith JM, Siwek L, et al. Multicenter mitral valve study: a lateral approach using the da Vinci surgical system. Innovations. 2007;2:56Y61. 13. Svensson LG, Atik FA, Cosgrove DM, et al. Minimally invasive versus conventional mitral valve surgery: a propensity-matched comparison. J Thorac Cardiovasc Surg. 2010;139:926Y932. 14. Schroeyers P, Wellens F, De Geest R, et al. Minimally invasive video-assisted mitral valve surgery: our lessons after a 4-year experience. Ann Thorac Surg. 2001;72:S1050YS1054. 15. Torracca L, Lapenna E, De Bonis M, et al. Minimally invasive mitral valve repair as a routine approach in selected patients. J Cardiovasc Med (Hagerstown). 2006;7:57Y60. 16. Aybek T, Dogan S, Risteski PS, et al. Two hundred forty minimally invasive mitral operations through right minithoracotomy. Ann Thorac Surg. 2006;81:1618Y1624. 17. Pfannmu¨ller B, Seeburger J, Misfeld M, Borger MA, Garbade J, Mohr FW. Minimally invasive mitral valve repair for anterior leaflet prolapse. J Thorac Cardiovasc Surg. 2013;146:109Y113. 18. D’Alfonso A, Capestro F, Zingaro C, Matteucci S, Rescigno G, Torracca L. Ten years’ follow-up of single-surgeon minimally invasive reparative surgery for degenerative mitral valve disease. Innovations. 2012;7: 270Y273. 19. El-Fiky MM, El-Sayegh T, El-Beishry AS, et al. Limited right anterolateral thoracotomy for mitral valve surgery. Eur J Cardiothorac Surg. 2000;17: 710Y713. 20. Grossi EA, Loulmet DF, Schwartz CF, et al. Evolution of operative techniques and perfusion strategies for minimally invasive mitral valve repair. J Thorac Cardiovasc Surg. 2012;143:S68YS70. 21. Murzi M, Cerillo AG, Bevilacqua S, et al. Enhancing departmental quality control in minimally invasive mitral valve surgery: a single-institution experience. Eur J Cardiothorac Surg. 2012;42:500Y506. 22. Goldstone AB, Atluri P, Szeto WY, et al. Minimally invasive approach provides at least equivalent results for surgical correction of mitral regurgitation: a propensity-matched comparison. J Thorac Cardiovasc Surg. 2013;145:748Y756. 23. Cheng W, Fontana GP, De Robertis MA, et al. Is robotic mitral valve repair a reproducible approach? J Thorac Cardiovasc Surg. 2010;139:628Y633. 24. Jones BA, Krueger S, Howell D, Meinecke B, Dunn S. Robotic mitral valve repair: a community hospital experience. Tex Heart Inst J. 2005;32: 143Y146. 25. Gammie JS, Zhao Y, Peterson ED, O’Brien SM, Rankin JS, Griffith BP. Less-invasive mitral valve operations: trends and outcomes from The Society of Thoracic Surgeons Adult Cardiac Surgery Database. Ann Thorac Surg. 2010;90:1401Y1410. 26. Gao C, Yang M, Xiao C, et al. Robotically assisted mitral valve replacement. Thorac Cardiovasc Surg. 2012;143:S64YS67. 27. Kilic A, Shah A, Conte J, Baumgartner WA, Yuh DD. Operative outcomes in mitral valve surgery: Combined effect of surgeon and hospital volume in a population-based analysis. J Thorac Cardiovasc Surg. 2013;146: 638Y646.
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Cost-Benefit in Mitral Valve Surgery
CLINICAL PERSPECTIVE This cost-benefit analysis of robotic versus nonrobotic minimally invasive mitral valve surgery (mini-MVR) from Dr Hassan and his colleagues is an excellent contribution. To look at clinical benefit, they examined 21 studies involving more than 9600 patients. Thirteen studies compared mini-MVR with conventional MVR, whereas the others compared robotic MVR with conventional approaches. The cost analysis examined three studies that included only 334 patients and their own institutional experience. They concluded that there seemed to be both a clinical and a cost benefit to minimally invasive as opposed to robotic MVR. In terms of clinical benefit, there was a significantly higher rate of stroke, atrial fibrillation, and conversion to conventional sternotomy in the robotic patients. There was a higher percentage of repairs in the robotic versus the mini-MVR group. However, this was likely due to the individual institutional experiences. In terms of cost, there was a distinct advantage to the mini-MVR over the robotic MVR group. The excess cost per case was $350 for the mini-MVR patients and $2064 for the robotic patients. This is an important study, and these analyses are extremely valuable when assessing new technology. Any new technology must provide clinical value. Value is defined as quality divided by cost. With the excess cost of robotic valve surgery when compared to mini-MVR, one would have to see a distinct clinical benefit to provide similar value. In this literature review, the clinical value of robotic technology is clearly less than that for mini-MVR. There are limitations to the study. These are all retrospective multicenter analyses and subject to inherent biases. Moreover, they included data from both inside and outside of the United States. Their cost data were based on a relatively small number of patients, and they did not look at fixed costs, only variable costs. Moreover, it was difficult to define the level of experience of the different centers, and a number of the studies had only a small number of patients. However, the authors are to be congratulated for performing this analysis. It is provocative and suggests that robotic valve surgery does not provide clinical value when compared with a nonrobotic minimally invasive approach. However, this hypothesis would need to be tested in larger prospective trials or ideally in a randomized, multicenter approach. It is unlikely that this will ever be performed because of the inherent prejudices of many centers. In the meantime, this review provides food for thought.
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