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30. Nakata M, Saeki H, Yokoyama N, Kurita A, Takiyama W, Takashima S.

Pulmonary function after lobectomy: video-assisted thoracic surgery versus

thoracotomy. Ann Thorac Surg. 2000;70:938-41.

31. Kaseda S, Aoki T, Hangai N, Shimizu K. Better pulmonary function

and prognosis with video-assisted thoracic surgery than with thoracotomy.

Ann Thorac Surg. 2000;70:1644-6.

DiscussionDr David C. Rice (Houston, Tex). This study is important for a

number of reasons. First, it adds to the voluminous body of datashowing that VATS lobectomy, at least for straightforwardresections, is safer for patients than open lobectomy, especiallyfor high-risk patients. Second, it is the only large study of thistype that has been able to document a decreased operativemortality associated with VATS. Finally, it has demonstratedcontinued increased adoption of VATS lobectomy by surgeonsaffiliated with the Society of Thoracic Surgeons. Almost onehalf of the lobectomies in this study were performed by VATS,double the number just 6, 7 years ago.

The study had several obvious limitations, not the least of whichwas that apart from the spirometric measurements, we knownothing of the functional assessments that these high-riskpatients underwent that might have allowed or disallowed theircandidacy for surgery. Thus, the general applicability to an overallpopulation of patients with lung cancer at high risk is debatable.You appropriately dealt with the odd clumping of VATSsegmentectomy with lobectomy, and I applaud your use ofpropensity analysis. I have 4 questions.

I understand that patients who underwent sleeve lobectomywere excluded from the analysis, but did you also exclude patientsundergoing more extensive procedures such as bilobectomy, chestwall resection, diaphragm resection, or redo resections that mighthave negatively biased the open group?

Second, the Duke University group published a study last yearthat used the same database for an earlier cohort and analyzed bythe same biostatistical group that showed a greater incidence ofpulmonary morbidity but a relatively less overall reduction inmortality related to VATS. How do you account for the differencesbetween that study and yours?

Third, it has been shown by several other studies that theoperative outcomes after lobectomy are highly related to centervolume. Is it possible that the centers that performed VATS werealso the high-volume centers and did you or do you plan onstudying hospital volume as a possible contributing factor?

Finally, if the ppoFEV1 and ppoDLCO of <40% were notnecessarily associated with prohibitive morbidity after VATSlobectomy, at what value should we stop?

I congratulate you on an excellent presentation and thank youfor allowing me to review the report and slides well in advance.

Dr Burt. Thank you, Dr Rice, for reviewing the report and foryour insightful questions.

In terms of your first question, we did exclude patients whowere undergoing sleeve lobectomy and we did exclude patientswho underwent bilobectomy. We included patients who wereundergoing a reoperation; that was about 5.5% of the cases. Thatwas controlled for in our multivariate analysis and was balancedin our propensity analysis. Your point on the additional chest

10 The Journal of Thoracic and Cardiovascular Surge

wall resection and diaphragm resection is a good one, and althoughthese probably represented a low overall fraction of lobectomies,they were not controlled for in the present study.

Then your second question is about the report by Drs Ceppa andOnaitis last year in the Annals of Surgery.What they showed, usingmostly the previous version of the Society of Thoracic Surgeonsdatabase was that patients who underwent open lobectomy hadincreased cardiopulmonary complications if their FEV1 was<60%. Thus, patients whose FEV1 was<60% who underwentopen lobectomy had greater rates of postoperative complicationsthan a nonmatched VATS comparison group. Their overall rateof complications was about 22% in the open group and 18% inthe VATS group, greater than our overall complication rate. I didnot show it in the slides, but our overall rate of cardiopulmonarycomplications was 13% in the open group and 7% in the VATSgroup, which was significantly lower. I believe that this wasprobably a function of time. We considered the period from2009 to 2011, and the previously quoted study was from 2002 to2009 or 2010, and it is likely that our complication rates havebeen decreasing over time.

Your third point is about center volume. As you alluded, it hasbeen shown that for a variety of operations, higher volume centershave had lower rates of operative risk, and we did not consider thisspecifically in our study. However, I will tell you that I did surveyall the input data from the 186 institutions that contributed to theSociety of Thoracic Surgeons database during the study period,and no one or several institutions disproportionately contributedto the number of VATS operations.

Then, your final question is really, I guess, the crux of ourreport, which is how should these data be interpreted. It was notour intention to decide a numeric value for which there is aprohibitive, or high, or low risk of surgery. That is why I showedthe data in the figure so that practicing thoracic surgeons canmake an informed decision of the risk at different levels of ppo.As you also alluded, this is only 1 variable in the equation whenevaluating patients, and it is a combination of clinical judgmentand experience and an evaluation of patient frailty and a numberof other patient-related factors that are just as important or moreimportant than any of the numbers I have shown you. However,I hope I did convince you that patients with compromisedpulmonary function can undergo VATS lobectomy with relativesafety.

Dr Scott Swanson (Boston, Mass).Bryan, that was an excellentpresentation. You have obviously been well trained. My questionfor you is, do you think these data about marginal reserve relatedto DLCO is generalizable to other types of marginal reserve,whether cardiac or age or other evidence of frailty, such thatVATS would be an improvement in those groups as well?

Number 2, you are a practicing cardiothoracic surgeon. How doyou use these data? Do you believe that VATS lobectomy is aparadigm shift and allows you to perform operations that youmight not have had you only been able to perform openthoracotomy?

Dr Burt. In terms of your first question, these are multivariatepredictors; thus, it takes into account all the other variables. Othershave shown that if you have something else in addition to acompromised pulmonary function, such as increased age orworsening cardiac function, your risk can double. Thus, I think

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all those measures must be accounted for separately when you areevaluating a patient.

Regarding your second question about a paradigm shift, I thinkso. Obviously, less trauma and better pulmonary recoveryoccurs after VATS lobectomy. I believe these data represent animprovement in the care of patients with lung cancer who wouldpreviously not have been able to undergo lobectomy secondaryto compromised pulmonary function and who now couldpotentially be offered VATS lobectomy.

Dr Joel D. Cooper (Philadelphia, Pa). Dr Burt, I enjoyed yourreport, and it is obvious that a great deal of work and data miningwent into it. Although I disagree with your conclusion, I think themost important point is being missed. It is not a question of VATSversus open. We could argue that all day, and I happen to disagreewith you. What I am mainly concerned about however, are otherissues.

Your abstract read ‘‘predicted postoperative values of<40% ofnormal are considered prohibitive for lobectomy owing to highrates of mortality and cardiopulmonary complications.’’ Thatsimply is not true, and this is not the first report that has madethat statement. What you are saying is that a preoperative FEV1of 50% of the predicted value is considered too high a risk forlobectomy. You do not believe that, do you? The results youhave reported for the open procedures show, overall, a rathergood result. Thus, I am concerned about such a misleadingstatement, and my first question is, do you really believe it,regardless of whether the procedure is to be VATS or open?

Dr Burt. I submit that statement might have been a littleaggressive in the abstract, which I did not actually end up includingin the report. What I do believe and what the American College ofChest Physicians recommends is that a ppo value of <40%identifies a patient at high risk, and their national guidelines wouldsuggest that patients with a ppoFEV1 of<40% deserve additionalworkup, possibly cardiopulmonary exercise testing. They havestated that a ppoFEV1 of<30% is a prohibitive risk and that thosepatients should perhaps undergo sublobar resection or stereotacticbody radiotherapy instead of lobectomy. So, I do not believe that appo of <40% is prohibitive risk, but I believe it does identifypatients at very high risk.

If you look at the data, the mortality was 5 times greater amongthe>600 matched patients with a ppoFEV1 of<40% undergoingopen compared with VATS lobectomy. To me, that is a prettyimpressive statistic.

Dr Cooper. But with VATS, you report a 5 times greatermortality when you operate on patients who have a predicted post-operative FEV1 of 20% to 30% compared with your group of

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patients whose predicted postoperative FEV1 was<20%. So, thereare many ways one can interpret or play with the data.

The second point is I do not believe that the prediction of thepostoperative FEV1 is helpful, especially as one goes to lowerand lower values of the FEV1. The patients with the poorestpreoperative FEV1s usually have the most severe emphysema.In those patients, the actual postoperative FEV1 after lobectomyusually increases, not diminishes, because of the so-called volumereduction effect of removing a lobe that has a significant degree ofemphysematous destruction. Therefore, why use the prediction ofthe postoperative value in such patients? Returning to my firstpoint, what you are suggesting is that a patient with an actualFEV1 of <50% of the predicted value would represent aprohibitive risk of morbidity and mortality after lobectomy. Thisleads to my last and greatest concern. By accepting as your prem-ise, someone else’s guidelines, especially nonsurgeons’ opinionsas to what does and does not constitute prohibitive risk, we areabrogating our responsibility as thoracic surgeons. You know aswell as I do that many factors must be considered in selectingappropriate candidates for lung resection. These include theseverity, pattern, and distribution of the emphysematous changes,the overall performance status of the patient, how much of thereduced FEV1 has resulted from airway disease and how muchfrom emphysema, and so forth. We reported 10 years ago at thismeeting on 21 consecutive patients with a FEV1 <30% whounderwent resection of lung cancer, 18 of the 21 beinglobectomies. None of these patients had died within the first12 months. Thus, my question is what are we going to do to changethe misconception in the nonthoracic community as to what doesand does not constitute a prohibitive risk of morbidity andmortality?

Dr Burt. I would like to reply to your first point about theemphysema. It is clear that the FEV1 is not as accurate inpatients with chronic obstructive pulmonary disease, and 1limitation of the study was that we could not know whichnonfunctional emphysematous lobes were removed. Thesepatients perhaps benefited from the lung volume reductionsurgery effect of a lobectomy. So, that is a limitation of the study.However, the DLCO has been shown, even in patients withcompromised pulmonary function or decreased air flow orchronic obstructive pulmonary disease, to still predict operativemortality.

I understand your point. I think we all have to make our owndecisions. I am not suggesting that we follow others’ guidelines,but I think there is a clear separation between those undergoingVATS and open lobectomy based on at least these parameters.

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