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J Thorac Cardiovasc Surg 2005;130:245-249
© 2005 The American Association for Thoracic Surgery
Editorial |
Department of Cardiothoracic Surgery, UCLA Medical Center, Los Angeles, Calif
Received for publication February 24, 2005; accepted for publication March 1, 2005. * Address for reprints: Gerald D. Buckberg, MD, David Geffen School of Medicine at UCLA, 10833 Le Conte Ave, 62-258 CHS, Los Angeles, CA 90095 (Email: gbuckberg{at}mednet.ucla.edu).
A recent editorial, the first on this subject, appeared in the Journal
1
: "To STICH or not to STICH: We know the answer, but do we understand the question?" Although the article indicates the answer is "to STICH," this report asks whether the STICH investigators’ response understood the question.
Patient Selection and Inclusion Criteria
The underlying principle of the STICH (Surgical Treatment for IschemiC Heart failure) trial involves recognition of the potentially lethal complications of enlarging ventricular volume, and its questions are closely linked to volume measurements, the first entry criteria for inclusion in the trial. This fundamental concept stems from the seminal work of White and colleagues,
2
showing how increased left ventricular end-systolic volume affects mortality. For example, Figure 1A shows that doubling of mortality follows doubling of volume and defines how death rate worsens after the progressive end-systolic volume expansion. Measuring ventricular volume is a central ingredient of the STICH trial and is expressed as left ventricular end-systolic volume index (LVESVI) in the database. The congestive heart failure (CHF) community must recognize that this vital measurement reflects a major departure from conventional analysis because ejection fraction is now the traditional marker. White and colleagues
2
have shown, in Figure 1B, the survival discrepancy between conventional ejection fraction and LVESVI measurement. Unfortunately, this central issue is never raised in the invited editorial that just appeared in the Journal.
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published a nonrandomized report in which the entry criterion was LVESVI of approximately 60 mL/m2 and compared medical therapy and CABG. Follow-up data (Figure 2) demonstrated that prognosis was determined on the basis of LVESVI changes over 4 years and was independent of the treatment category. The STICH trial will place randomization into this equation.
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Consequently, the surgeon and cardiologist must ask 3 different questions than those posed by the authors of this article: (1) How much asynergy (ie, the scar nidus of dilation) exists; (2) is there sufficient compensatory muscle (seen by means of magnetic resonance imaging [MRI], ventriculography, echocardiography, and nuclear medicine studies of remote regions) to resume function; and (3) what is the ventricular volume, a measurement obtained by means of MRI, biplane ventriculography, nuclear medicine, and echocardiography?
It seems that a very important task of this prior editorial is to advise the cardiologist or surgeon who wonders how to treat such a patient that the enclosed workup does not provide the STICH team with sufficient information to answer the basic questions that underlie this trial. Failure to address these issues during a response to individuals posing this STICH trial question suggests that the authors do not (1) use these basic criteria in their selection or (2) advise inquiring physicians that correct use of these inclusion criteria is essential to understand this trial.
The STICH protocol uses LVESVI measurement to make decisions about placing patients into the 3 study groups. If volume is less than 60 mL/m2, the intervention decision relates to comparing the effects of either using medical treatment or adding CABG. Recruitment is down in this 1600-patient cohort because cardiologists are aware that all trials and registries show the benefit of CABG in improving survival in ischemic patients, as summarized in their reported Coronary Artery Surgery Study, and simply do not wish to withhold revascularization in patients with ischemic CHF. More importantly, the editorial does not define limitations of the 3-year observation period, does not emphasize the downward survival trajectory observed with longer follow-up intervals,
4,5
and excludes the recent Duke database showing the advantages of CABG versus medical treatment over a 10-year follow-up interval.
6
Of interest, this Duke database did not include recurrent CHF as a late problem
7
because they only followed death, new myocardial infarction, or repeat CABG as adverse follow-up events.
If volume is greater than 60 mL/m2, a frequent finding in patients with CHF, the decision question relates to how SVR fits into the treatment scheme in 1200 patients. A first cohort is divided into 600 patients who do not have either angina or critical coronary lesions and are treated with medical therapy, CABG, or CABG and SVR. The second cohort involves a 600-patient subgroup with angina or critical lesions that will undergo CABG with or without SVR. There is no problem in recruitment in this last group.
Viability and Revascularization
The issue of viability is somewhat confusing in this editorial because an inclusion criterion for STICH consideration is infarction of the anterior septal region. Consequently, observation of anterior viability in the STICH trial is not as vital in the asynergic scar (the size of which must be measured as >35% of LV perimeter on right anterior oblique ventriculography) as determination of viability of remote muscle that might develop compensatory improvement after revascularization. This remote muscle is viable in the patient presented in the editorial. However, the responsibility of the authors is to clarify the trial focus by emphasizing that the surgeon and cardiologist must look at the compensating muscle
8
rather than the scar, which currently remains the focal area of interest during current viability testing. Addressing remote muscle should be an important component of this editorial because such leadership will improve the surgeon’s and cardiologist’s understanding of the decision tree that underlies the STICH trial.
Additionally, discussions about the importance of viability studies while making decisions about the role of surgical revascularization should overview the recent work of Mahrholdt and associates.
9
Their findings emphasize the gadolinium aspect of MRI scans (MRI is a part of the STICH trial) by analyzing the amount of damage within the infarct area scar. This is a critical aspect of the evaluation process because most patients show an akinetic rather than a dyskinetic scar. This wall motion finding relates to the consequences of reperfusion by thrombolysis or percutaneous transluminal coronary angioplasty, which salvages the epicardial (and potentially mid myocardial) surface of the infarct region. Early reflow will prevent transmural bulging (dyskinesia) and creates the akinetic area that differs from the aneurysm previously treated by Cooley and coworkers,
10
when reperfusion strategies were not used. The authors should use this new MRI information to explain why successful revascularization will not allow contractile recovery if more than 50% of muscle is scarred by gadolinium.
9
They should also point out that the critical issue is not viability of the scar but rather recognition of why segmental contraction of the scar cannot improve through revascularization of regions containing extensive nonviable muscle. The SVR procedure understands this logic because the operation excludes this nonfunctional region.
Surgical Ventricular Restoration for Ischemic Heart Failure
The authors present a limited overview of the background role of SVR to treat the dilated heart. Aside from excluding the vital importance of volume measurements,
2
they should focus on past reports that clarify why bigger ventricular volumes might limit prognosis.
11,12
Di Donato and coworkers
8,12
reported longitudinal survival studies that demonstrate better survival and functional outcome after SVR interventions when LVESVI is not markedly increased. Athanasuleas and associates
13–15
found similar late findings, especially in the recent 5-year follow-up of 1198 patients undergoing SVR in the recent RESTORE
*
team report. The critical role of volume must be clarified because the authors introduce a CABG article that uses ejection fraction rather than volume measurements to quantify recovery as a contrast to SVR findings of the RESTORE group.
16
Luciani and coworkers
7
provided evidence of the prognostic importance of volume rather than ejection fraction, in which a 7-year CABG patient study follow-up identified differences between improved ejection fraction (in his patients) and observed progressive increase of ventricular volume and CHF worsening. These adverse clinical events existed despite improved survival after CABG therapy, and the authors stress the importance of measuring ventricular volume and body oxygen uptake to assess recovery. Furthermore, Di Donato and coworkers
12
(Figure 3) have confirmed the data of White and associates
2
by showing that volume, rather than ejection fraction, is the vital prognostic component. Yamaguchi and colleagues
17
have also emphasized the prognostic importance of LVESVI by showing impaired prognosis and increasing incidence of CHF when preoperative LVESVI is greater than 100 mL/m2. This 1998 observation is now updated
17,18
by a 2005 report showing that the 54% mortality that followed successful CABG in a patient population whose preoperative LVESVI value was greater than 100 mL/m2 was improved to 90% 5-year survival after restoration (SVR) to produce LV rebuilding.
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Evidence-based medicine is the recurrent theme in surveying randomized series. The validity of surgical trials powered to yield creditable results must also address 2 other components: technical proficiency and competent myocardial protection. The importance of adding this credibility concept to surgical trial design was clear from a 1977 Veterans Affairs’ randomized CABG study that was done in 597 patients that included 286 surgical and 310 medical patients.
19
The authors reported 5.6% surgical mortality, with postoperative deaths ranging from 2% to 12%, a result that was closely linked to an experience within 12 participating individual centers
19
that showed similar 36 month outcomes. In 1978, the Cleveland Clinic reported a nonrandomized series of 1000 patients with a mortality of less than 1%.
20
The overall clinical effect favored experience because obstructed vessels are now treated with revascularization, and current dialogue only relates to creation of the open vessel by using either angioplasty or surgical approaches.
The STICH trial might fall into a similar category because 2800 patients will be studied within the many US and international centers. The editorial states that there is not general acceptance of the SVR procedure that will be performed in only 500 patients among more than 90 participating STICH centers. The potential of approximately 5 patients per center suggests that ensuring competence is essential during evaluation of the role of SVR in high-risk patients with CHF. The recent RESTORE report in 1198 patients (from only 11 contributing centers) might provide some guidelines by reporting 5.3% operative mortality: 4% after SVR and CABG and 8.7% if mitral repair or replacement are added in very large ventricles. This recent RESTORE database might set a benchmark for in-hospital mortality to be expected from STICH centers. Statisticians accurately establish evidence-based medicine, but input for their trial database must involve a safe level of technical competence and satisfactory myocardial protection, so that results can avoid inexperience bias that will invalidate any surgical method.
Conclusions
The questions asked by this current editorial suggest that the editorial of STICH investigators should have advised the cardiologist or surgeon who asks the question "How would you treat this patient?" that the initial workup summary did not have the right measurements. Information on asynergy, remote muscle, and volume are central factors in the STICH evaluation. An important message involves clarifying that the referring physician must know that ejection fraction is a less helpful number than LVESV and suggesting how to obtain this key measurement.
Furthermore, advice about the viability of remote muscle is a new theme and should be emphasized. Additionally, they should define ways that MRI allows study of the underlying scar of the akinetic heart to improve understanding of why its grafting or exclusion might affect prognosis, especially in the 1200 patients with CHF who become SVR candidates. Identifying limitations of 3-year follow-up is needed because medical therapy options are vastly improved. Recognizing this limitation naturally leads to emphasizing the importance of long-term follow-up intervals that are a critical STICH trial component, especially because 10-year data about CABG in the Coronary Artery Surgery Study are discussed. Finally, focus on the role of experience during any randomized surgical series is important to avoid unbiased results. Surgeons act and statisticians count, and both must be done well to define how any randomized or nonrandomized trial can affect future actions.
Footnotes
* Reconstructive Endoventricular Surgery, returning Torsion Original Radius Elliptical Shape. 
References
This article has been cited by other articles:
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  R. B. Prucz, E. S. Weiss, N. D. Patel, L. U. Nwakanma, W. A. Baumgartner, and J. V. Conte Coronary Artery Bypass Grafting With or Without Surgical Ventricular Restoration: A Comparison Ann. Thorac. Surg., September 1, 2008; 86(3): 806 - 814. [Abstract] [Full Text] [PDF]
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H. J. Geissler Invited commentary Ann. Thorac. Surg., October 1, 2007; 84(4): 1287 - 1287. [Full Text] [PDF]
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M. Pocar, A. Moneta, A. Grossi, and F. Donatelli Coronary Artery Bypass for Heart Failure in Ischemic Cardiomyopathy: 17-Year Follow-Up Ann. Thorac. Surg., February 1, 2007; 83(2): 468 - 474. [Abstract] [Full Text] [PDF]
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 S. G. Lloyd, G. D. Buckberg, and the RESTORE Group Use of cardiac magnetic resonance imaging in surgical ventricular restoration Eur. J. Cardiothorac. Surg., April 1, 2006; 29(Suppl_1): S216 - S224. [Abstract] [Full Text] [PDF]
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