STICH Trial-
A Critical Appraisal

    -Dr Akshay Mehta

  Dr B Nanavati Hospital
   Asian Heart Institute
Background 1
   CAD is the commonest substrate for HF

   The role of CABG for Rx of CAD with HF not clearly
    established.

   Landmark trials in the 1970s comparing CABG with
    medical therapy alone, were predominantly in pts
    with chronic stable angina.
Background 2
   These trials excluded patients with severe LV
    dysfunction (patients with an ejection fraction of
    <35%).

   A meta-analysis of the trials showed that 7.2% of
    the patients who underwent randomization had an
    EF of 40% or less

   Only 4.0% had primary symptoms of heart failure
    rather than angina

   Predate the major developments in medical
    therapy and cardiac surgery
Surgical Treatment for Ischemic
   Heart Failure –STICH Trial


                Two Hypotheses
         I
                                   II


        Surgical
                           LV restoration
    Revascularization
                            hypothesis
       Hypothesis
I] Surgical Revascularization
                Hypothesis
    Primary Hypothesis:
    In patients with HF, LVD and CAD amenable to surgical
    revascularization, CABG added to intensive medical therapy
    (MED) will decrease all-cause mortality compared to MED
    alone.

 Secondary hypothesis:
 Presence and extent of dysfunctional but viable myocardium,
  as defined by radionuclide imaging, dobutamine stress
  echocardiography, or both, will identify patients with greatest
  survival advantage of MED + CABG compared with MED
  alone.
II] LV restoration hypothesis
In patients with dominant anterior wall LV akinesia or
 dyskinesia, LV shape and size optimization by SVR
 combined with CABG and MED improves long-term
 survival free of cardiac hospitalization compared
 with CABG and MED without SVR.
Original Article
  Coronary-Artery Bypass Surgery in Patients
      with Left Ventricular Dysfunction

Eric J. Velazquez, M.D., Kerry L. Lee, Ph.D., Marek A. Deja, M.D., Ph.D., Anil
 Jain, M.D., George Sopko, M.D., M.P.H., Andrey Marchenko, M.D., Ph.D.,
    Imtiaz S. Ali, M.D., Gerald Pohost, M.D., Sinisa Gradinac, M.D., Ph.D.,
  William T. Abraham, M.D., Michael Yii, M.S., F.R.C.S., F.R.A.C.S., Dorairaj
Prabhakaran, M.D., D.M., Hanna Szwed, M.D., Paolo Ferrazzi, M.D., Mark C.
  Petrie, M.D., Christopher M. O'Connor, M.D., Pradit Panchavinnin, M.D.,
 Lilin She, Ph.D., Robert O. Bonow, M.D., Gena Roush Rankin, M.P.H., R.D.,
       Robert H. Jones, M.D., Jean-Lucien Rouleau, M.D., for the STICH
                                 Investigators



                                                             N Engl J Med
                                                       Volume 364(17):1607-1616
                                                            April 28, 2011
STICH Revascularization Hypothesis

                     Randomized MED only
                            602

     1212
                      Randomized CABG
  HF, LVD and CAD           610
  amenable to CABG
All-Cause Mortality
            Adjusted HR 0.82
            (0.68,0.99)
            Adjusted P = 0.039
Thus Primary End Point:


As randomized, CABG led to a 14% RRR in all-cause
          mortality compared to MED
                (not significant)
Has CABG no role in Ischemic HF ?


“We were unable to show a significant benefit for
CABG in our primary analysis, but if you dive deeper,
the data are much more supportive of bypass
surgery,”

                               -Dr Eric J. Velazquez, M.D.
Cardiovascular Mortality
          HR 0.81 (0.66, 1.00)
          P = 0.050
          Adjusted HR 0.77 (0.62, 0.94)
          Adjusted P = 0.012
• Death from any cause adjusted outcomes models.
  Model 1: surgical ventricular reconstruction eligibility
  (i.e., enrollment stratum); Model 2: Model 1 + age,
  sex, race, baseline New York Heart Association heart
  failure class, myocardial infarction history, previous
  revascularization, best available core lab ejection
  fraction; Model 3: Model 2+ number of diseased
  vessels, presence of chronic renal insufficiency, mitral
  regurgitation grade, stroke history, atrial fibrillation
  or flutter.
Death or Cardiovascular
Death or Cardiovascular hospitalization
       Hospitalization-nt done
                    HR 0.74 (0.64, 0.85)
                    P < 0.001
                    Adjusted HR 0.70 (0.61, 0.81) P <
                    0.001
Time-varying Hazard Ratios




0.25   0.5   1   2            4

   CABG              MED
   group             group
   better            better
STICH Revascularization Hypothesis
Effect of Actual Treatment Received
                             1212



Randomized       602                         610        Randomized
  MED only                                              CABG


           537         65              555         55

Received                    Received                      Received
   MED                       CABG                         MED
             Per protocol: MED (537) vs. CABG (555)
             As treated:   MED (592) vs. CABG (620)
All-Cause Mortality
All cause mortality-as treated
    — As Treated (nt done)
                    HR 0.70 (0.58 – 0.84)
                    P < 0.001
All-cause mortality:Mortality
          All-Cause as per protocol
      — As Per Protocol (nt done)
                         HR 0.76 (0.62, 0.92)
                         P = 0.005
Conclusions
   STICH trial supports bypass surgery on top of best medical
    therapy vs medical therapy alone to reduce cardiovascular
    morbidity and mortality

   “Although the totality of information supports CABG, there is
    an early hazard

   A fair approach is to evaluate each patient’s prognosis. If they
    have a low likelihood of living two years or don’t want to take
    the risk of having surgery medical therapy may be a good
    option.”
                                                    - Dr Eric Velazquez
   Also, as a start, aggressive medical therapy should be initiated
    and optimized, according to evidence-based guidelines.

   For patients with persistent or progressive symptoms,
    revascularization can be offered.

   Patients who are being treated for HF should be evaluated for
    coronary disease

   Heart failure without angina shouldn't exclude patients from
    an angiographic evaluation.
Myocardial Viability and Survival
in Ischemic Left Ventricular Dysfunction


              Robert O. Bonow, MD
       On behalf of the STICH Trial Investigators
STICH Viability Hypothesis

In this prospective substudy, we tested the hypothesis
   that assessment of myocardial viability identifies
 patients with CAD and LV dysfunction who have the
   greatest survival benefit with CABG compared to
              aggressive medical therapy
STICH Viability
Viability testing was optional at enrolling sites and was not a
                  prerequisite for enrollment.
                                           Dobutamine echo
           SPECT protocols:
                                              protocols:
       • Thallium-201 stress-          • Staged increase in
         redistribution-                 dobutamine starting
         reinjection                     at 5 μg/kg/min
       • Thallium-201 rest-
         redistribution
       • Nitrate-enhanced Tc-
         99m perfusion
         imaging
Patients randomized
                                            Patients with no
           Patients with no                 usable myocardial
           myocardial viability test        viability test


                   594                            611

                                              Unusable test
1212                                   17      • Timing
                                               • Poor quality


                   618                            601

                Patients with               Patients with usable
                 myocardial                      myocardial
                viability test                  viability test
Patients randomized in STICH
        Revascularization Hypothesis
                                       1212



                  SPECT      Dobutamine echo
                  n=471        n=280



                       321 150 130
                                                              Patients with no
                                                   611        usable myocardial
                                                              viability test
     Patients with
usable myocardial          601
      viability test                     114
                                                  Nonviable

                                 487
                                         Viable
STICH Viability Results

        …demonstrate that association between
        myocardial viability and survival, is non-
     significant when subjected to a multivariable
    analysis that includes other baseline variables.


    …fail to demonstrate a significant interaction
      between myocardial viability and medical
      versus surgical treatment with respect to
      mortality, whether assessed according to
    treatment assigned (intention to treat) or to
           the treatment actually received.
STICH Viability


Implications:
   In patients with CAD and LV dysfunction, assessment of
   myocardial viability does not identify patients who will
   have the greatest survival benefit from adding CABG to
   aggressive medical therapy
However, Limitations of the Trial
Patients were selected for viability testing individually at the
physicians' discretion

Patients represent a subpopulation of STICH (<50%)

The number of patients without substantial viability was small(114)
which limited statistical power

Use of two different imaging methods for assessing myocardial
viability and their limitations of specificity/sensitivity.

Analysis limited to SPECT and dobutamine echo, not PET or cardiac
MRI
              while the analysis looked at "substantial viability" as an "all-or-none" variable,
              decisions whether to revascularize or not have generally depended on the
              extent of viability—that is, as a continuous variable.
Take home message:
Despite all its imperfections the viability study suggests that assessment of
 myocardial viability alone may not be the deciding factor in selecting the
 best therapy for patients with ischemic heart disease and LV dysfunction.

Besides viability one should also look at other factors like target vessels, LV
                              volumes, EF etc.


This is specially true if SPECT or Dobutamine echo only are used for viability
                                     testing.

    Whether they have viability or not, STICH like patients benefit from
coronary bypass and we shouldn't be using viability studies such as these to
                  exclude patients from cardiac surgery.

We should await similar randomized studies with other methods of viability
                          detection like MRI etc.
Myocardial Viabilityand Mortality
                        Myocardial Viability and Mortality
                          1.0                                       Variables associated with mortality
                                                                                                   Chi-square     p

                                                                        Risk score Chi-          p33.26         <0.001
                          0.8                                                    square
                                                                        LV ejection fraction      24.80         <0.001
                                    HR         95% Cl scoreP
                                                     Risk
                                                                        LV EDVI
                                                                                   33.26       <0.001
                                                                                                  35.36         <0.001
                                    O.65       0.48 0.86 0.003 LV ESVI 24.80
                                                     LV ejection fraction                      <0.001
         Mortality Rate




                                                     LV EDVI                       35.36          33.90
                                                                                               <0.001           <0.001
                          0.6
                                                     LV ESVI            Myocardial viability
                                                                                   33.90           8.54
                                                                                               <0.001            0.003
                                                        Myocardial viability        8.54           0.003

                          0.4
                                                                                               50%


                          0.2                                                                  33%



                          0.0
                                0          1             2         3       4                   5            6
                                                        Years from Randomization
Without viability
With viability
Myocardial Viability and Mortality
                           Univariate            Multivariable
Variable       No.
                      Chi-square   p value   Chi-square   p value



SPECT and/or DE 601     8.54       0.003       1.57       0.210


SPECT alone    471      7.35       0.007       0.58       0.444


DE alone       280      1.18       0.277       0.42       0.518
Myocardial Viability and Cardiovascular Mortality
                                          Univariate        Multivariable
                                       Chi-square p value Chi-square p value
            HR 95%       Cl       P
            0.61 0.44   0.84   0.003
                                         8.81     0.003      0.91     0.339
Myocardial Viability and Mortality + CV Hospitaliztion




                                Univariate            Multivariable

                            Chi-square   p value   Chi-square   p value

                              20.27      <0.001      8.60        0.003
Patients with viability tests

                                   601
Patients with                                           Patients
  myocardial                                            without
     viability       487                         114    myocardial
                                                        viability



             243           244           60            54
              MED          CABG           MED          CABG
             49.9%         50.1%         52.6%         47.4%
Myocardial Viability and Mortality




                                     56%

                                                                                        35%
                                     42%
                                                                                        31%




Subgroup            N     Deaths   HR       95% CI                                 Interaction
                                                                                     P value
Without viability   114    58      0.70    0.41, 1.18                                0.528
With viability      487   178      0.86    0.64, 1.16
                                                        0.25    0.5   1       2
                                                         CABG              MED
                                                         better           better
   the patients without substantial viability, "who had perhaps
    less likelihood of functional recovery [than those with
    substantial viability], did as well from CABG as patients who
    did. . . . I think that's what we have to take away from this: we
    shouldn't be using [viability] studies to exclude patients from
    cardiac surgery
                                                    -Dr Eric Velazquez
Surgical Treatment for Ischemic
   Heart Failure –STICH Trial
                      In patients with HF, LVD < 35% and
                     CAD amenable to CABG, CABG +MED
                       will decrease all-cause mortality
               I      compared to MED alone+ (Viability
                                   Substudy)

  Hypotheses
                     In pts with dominant anterior wall LV
               II     akinesia or dyskinesia, SVR + CABG +
                    MED > hosp free survival compared with
                            CABG + MED without SVR.
For management of patients with
HF with surgically revascularizable CAD
      and decreased LV function
      (1) Is contemporary CABG surgery superior to
       contemporary medical/secondary prevention
        therapy in prolonging survival in these pts?

     (2) Among patients with significant anterior wall
          dysfunction, does the addition of surgical
          ventricular reconstruction (SVR) to CABG
           improve hospitalization-free survival?
Surgical Treatment for Ischemic Heart Failure
        trial stratum and treatment assignment.
                                             CAD
                                             EF <=
                                             0.35


                   SVR           YES                       NO                   NO
                                           Medical                SVR
                   eligible?                                                           Not in trial
                                           eligibility            eligible?
       NO
                               YES
                                                                          YES
       Stratum A
                               Stratum B
                                                                  Stratum C

                                                                                     CABG + SVR
MED           CABG

                                                         CABG + SVR           CABG
                           MED             CABG
Hypotheses :
  In patients with heart failure, left ventricular EF of 0.35 or less

(1)   coronary artery bypass grafting with intensive medical
      therapy improves long-term survival compared with
      survival with medical therapy alone, and
(2)   in patients with anterior left ventricular dysfunction,
      surgical ventricular reconstruction to a more normal left
      ventricular size plus coronary artery bypass grafting
      improves survival free of subsequent hospitalization for
      cardiac cause when compared with that with coronary
      artery bypass grafting alone.
Major STICH hypotheses
  Primary                                Major secondary
 Hypotheses                               hypotheses

  H1 Coronary revascularization
          hypothesis                           Presence and extent of
                                               dysfunctional but viable
  ● Improvement in myocardial                myocardium, as defined by
  perfusion by CABG combined                    radionuclide imaging,
  with MED improves long-term                     dobutamine stress
  survival compared with MED                 echocardiography, or both,
             alone.                           will identify patients with
                                             greatest survival advantage
  H2: LV restoration hypothesis             of MED and CABG compared
  ● In patients with dominant anterior              with MED alone.
   wall LV akinesia or dyskinesia, LV
  shape and size optimization by SVR
      combined with CABG and
 MED improves long-term survival free
  of cardiac hospitalization compared
   with CABG and MED without SVR.
The conclusions that can be drawn
from this substudy are limited by a
        number of factors
   Viability data were not available for all the patients who were
       enrolled in the STICH main trial.3 The substudy patients
      represent slightly less than 50% of the randomized group.
        Furthermore, viability testing was not performed on a
       randomly selected subgroup of patients but, rather, was
     obtained according to test availability and the judgment of
      the recruiting investigator. Third, the possibility cannot be
        excluded that the results of viability testing could have
            influenced subsequent clinical decision-making
   Despite the goal of uniform testing in this trial, the
    nonrandom and nonblinded selection for viability testing of
    only 601 of the 1212 eligible patients (49.6%) introduces
    considerable biases. Moreover, viability was defined in a
    binary fashion, and revascularization was not guided by the
    presence of viable myocardium within specific coronary-
    artery territories. In addition, the study is underpowered in
    the group with nonviable myocardium (i.e., 60 patients who
    received medical therapy and 54 patients who underwent
    CABG). Finally, viability assessment was restricted to single-
    photon-emission computed tomography (SPECT) and
    dobutamine echocardiography, which have well-known
    limitations in their ability to detect viability.1 We believe
    there is need for a randomized study of revascularization
    versus medical therapy after viability assessment with a
    standard technique such as contrast-enhanced magnetic
    resonance imaging (MRI) or positron-emission tomography
    (PET),1-3 which would allow targeted revascularization based
    on the presence of viable myocardium within specific
    coronary-artery territor
   "The analysis of intention-to-treat vs actual treatment is
    interesting, but the biological effect that our patients feel
    is what treatment they receive, and under that analysis,
    as a surgeon, you must conclude that patients with left
    ventricular dysfunction should receive coronary bypass." -
    Dr Steven Bolling (University of Michigan Cardiovascular
    Center, Ann Arbor)
Study Design
   Randomized controlled trial, non-blinded
   99 clinical sites in 22 countries
   Investigator-initiated and led
   National Heart, Lung and Blood Institute funded
   Duke Clinical Research Institute managed
   Independent Data and Safety Monitoring Committee
   Clinical Events Adjudication Committee
   Blinded Core Laboratories
Endpoints

Primary Endpoint
  – All-cause mortality


Major Secondary Endpoints
  – Cardiovascular mortality
  – Death (all-cause) + cardiovascular hospitalization
Important Inclusion Criteria

 LVEF ≤ 0.35 within 3 months of trial entry
 CAD suitable for CABG

 MED eligible

   – Absence of left main CAD as defined by an intraluminal
     stenosis of ≥ 50%
   – Absence of CCS III angina or greater
     (angina markedly limiting ordinary activity)
Major Exclusion Criteria
   Recent acute MI (within 30 days)
   Cardiogenic shock (within 72 hours of randomization)
   Plan for percutaneous intervention
   Aortic valve disease requiring valve repair or replacement
   History of more than 1 prior CABG
   Non-cardiac illness with a life expectancy of less than 3 years or
    imposing substantial operative mortality
Surgical Treatment for Ischemic Heart Failure
        trial stratum and treatment assignment.
                                              CAD
                                              EF <=         + CABG amenable
                                              0.35


                   SVR          YES                         NO         SVR       NO
                                            Medical
                   eligible?                                           eligible?        Not in trial
                                            eligibility
       NO
                               YES
                                                                            YES
       Stratum A
                               Stratum B
                                                                   Stratum C

                                                                                      CABG + SVR
MED           CABG

                                                          CABG + SVR         CABG
                        MED                CABG
STICH Viability

• All randomized patients were eligible for viability testing
  with SPECT myocardial perfusion imaging or dobutamine
  echo.


• Viability testing was optional at enrolling sites and was
  not a prerequisite for enrollment.
STICH Viability
Criteria for myocardial viability were prospective and pre-
  specified


SPECT:
  • 17 segment model
  • ≥11 segments manifesting viability based on relative
    tracer activity

Dobutamine echo:
  • 16 segment model
  • ≥5 segments with dysfunction at rest manifesting
    contractile reserve with dobutamine
STICH Viability
 Primary endpoint:
 ▪ All-cause mortality

Secondary endpoints:

  ▪ Mortality plus cardiovascular hospitalization
  ▪ Cardiovascular mortality
Intention-to-treat analysis
Baseline Characteristics
Patients With and Without Myocardial Viability
                                                 Viable         Non-Viable
Variable                                        (n=487)          (n=114)            P value

Age                                             61 ± 10            61 ± 9              NS
Multivessel CAD                                   73%                73%               NS
Proximal LAD stenosis                             64%                70%               NS

Risk score*                                    12.4 ± 8.7        12.9 ± 9.3            NS

Previous MI                                      76.6%              94.7%           <0.001
LV ejection fraction (percent)                   28 ± 8             23 ± 9          <0.001

LV end-diastolic volume index (ml/m2*
                                    )          117 ± 37           147 ± 53          <0.001

LV end-systolic volume index (ml/m2)             86 ± 33          116 ± 50          <0.001

                         Significant covariates in risk model: Age, renal function, heart failure,
                         ejection fraction, CAD index, mitral regurgitation, stroke
Background
• LV dysfunction in patients with CAD is not always an
  irreversible process, as LV function may improve substantially
  after CABG
• Assessment of myocardial viability is often used to predict
  improvement in LV function after CABG and improvement in
  survival
THANK YOU!!

Critical appraisal of Stitch Trial by Dr. Akshay Mehta

  • 1.
    STICH Trial- A CriticalAppraisal -Dr Akshay Mehta Dr B Nanavati Hospital Asian Heart Institute
  • 2.
    Background 1  CAD is the commonest substrate for HF  The role of CABG for Rx of CAD with HF not clearly established.  Landmark trials in the 1970s comparing CABG with medical therapy alone, were predominantly in pts with chronic stable angina.
  • 3.
    Background 2  These trials excluded patients with severe LV dysfunction (patients with an ejection fraction of <35%).  A meta-analysis of the trials showed that 7.2% of the patients who underwent randomization had an EF of 40% or less  Only 4.0% had primary symptoms of heart failure rather than angina  Predate the major developments in medical therapy and cardiac surgery
  • 4.
    Surgical Treatment forIschemic Heart Failure –STICH Trial Two Hypotheses I II Surgical LV restoration Revascularization hypothesis Hypothesis
  • 5.
    I] Surgical Revascularization Hypothesis Primary Hypothesis:  In patients with HF, LVD and CAD amenable to surgical revascularization, CABG added to intensive medical therapy (MED) will decrease all-cause mortality compared to MED alone. Secondary hypothesis:  Presence and extent of dysfunctional but viable myocardium, as defined by radionuclide imaging, dobutamine stress echocardiography, or both, will identify patients with greatest survival advantage of MED + CABG compared with MED alone.
  • 6.
    II] LV restorationhypothesis In patients with dominant anterior wall LV akinesia or dyskinesia, LV shape and size optimization by SVR combined with CABG and MED improves long-term survival free of cardiac hospitalization compared with CABG and MED without SVR.
  • 7.
    Original Article Coronary-Artery Bypass Surgery in Patients with Left Ventricular Dysfunction Eric J. Velazquez, M.D., Kerry L. Lee, Ph.D., Marek A. Deja, M.D., Ph.D., Anil Jain, M.D., George Sopko, M.D., M.P.H., Andrey Marchenko, M.D., Ph.D., Imtiaz S. Ali, M.D., Gerald Pohost, M.D., Sinisa Gradinac, M.D., Ph.D., William T. Abraham, M.D., Michael Yii, M.S., F.R.C.S., F.R.A.C.S., Dorairaj Prabhakaran, M.D., D.M., Hanna Szwed, M.D., Paolo Ferrazzi, M.D., Mark C. Petrie, M.D., Christopher M. O'Connor, M.D., Pradit Panchavinnin, M.D., Lilin She, Ph.D., Robert O. Bonow, M.D., Gena Roush Rankin, M.P.H., R.D., Robert H. Jones, M.D., Jean-Lucien Rouleau, M.D., for the STICH Investigators N Engl J Med Volume 364(17):1607-1616 April 28, 2011
  • 8.
    STICH Revascularization Hypothesis Randomized MED only 602 1212 Randomized CABG HF, LVD and CAD 610 amenable to CABG
  • 9.
    All-Cause Mortality Adjusted HR 0.82 (0.68,0.99) Adjusted P = 0.039
  • 10.
    Thus Primary EndPoint: As randomized, CABG led to a 14% RRR in all-cause mortality compared to MED (not significant)
  • 11.
    Has CABG norole in Ischemic HF ? “We were unable to show a significant benefit for CABG in our primary analysis, but if you dive deeper, the data are much more supportive of bypass surgery,” -Dr Eric J. Velazquez, M.D.
  • 12.
    Cardiovascular Mortality HR 0.81 (0.66, 1.00) P = 0.050 Adjusted HR 0.77 (0.62, 0.94) Adjusted P = 0.012
  • 13.
    • Death fromany cause adjusted outcomes models. Model 1: surgical ventricular reconstruction eligibility (i.e., enrollment stratum); Model 2: Model 1 + age, sex, race, baseline New York Heart Association heart failure class, myocardial infarction history, previous revascularization, best available core lab ejection fraction; Model 3: Model 2+ number of diseased vessels, presence of chronic renal insufficiency, mitral regurgitation grade, stroke history, atrial fibrillation or flutter.
  • 14.
    Death or Cardiovascular Deathor Cardiovascular hospitalization Hospitalization-nt done HR 0.74 (0.64, 0.85) P < 0.001 Adjusted HR 0.70 (0.61, 0.81) P < 0.001
  • 15.
    Time-varying Hazard Ratios 0.25 0.5 1 2 4 CABG MED group group better better
  • 16.
    STICH Revascularization Hypothesis Effectof Actual Treatment Received 1212 Randomized 602 610 Randomized MED only CABG 537 65 555 55 Received Received Received MED CABG MED Per protocol: MED (537) vs. CABG (555) As treated: MED (592) vs. CABG (620)
  • 17.
    All-Cause Mortality All causemortality-as treated — As Treated (nt done) HR 0.70 (0.58 – 0.84) P < 0.001
  • 18.
    All-cause mortality:Mortality All-Cause as per protocol — As Per Protocol (nt done) HR 0.76 (0.62, 0.92) P = 0.005
  • 19.
    Conclusions  STICH trial supports bypass surgery on top of best medical therapy vs medical therapy alone to reduce cardiovascular morbidity and mortality  “Although the totality of information supports CABG, there is an early hazard  A fair approach is to evaluate each patient’s prognosis. If they have a low likelihood of living two years or don’t want to take the risk of having surgery medical therapy may be a good option.” - Dr Eric Velazquez
  • 20.
    Also, as a start, aggressive medical therapy should be initiated and optimized, according to evidence-based guidelines.  For patients with persistent or progressive symptoms, revascularization can be offered.  Patients who are being treated for HF should be evaluated for coronary disease  Heart failure without angina shouldn't exclude patients from an angiographic evaluation.
  • 21.
    Myocardial Viability andSurvival in Ischemic Left Ventricular Dysfunction Robert O. Bonow, MD On behalf of the STICH Trial Investigators
  • 22.
    STICH Viability Hypothesis Inthis prospective substudy, we tested the hypothesis that assessment of myocardial viability identifies patients with CAD and LV dysfunction who have the greatest survival benefit with CABG compared to aggressive medical therapy
  • 23.
    STICH Viability Viability testingwas optional at enrolling sites and was not a prerequisite for enrollment. Dobutamine echo SPECT protocols: protocols: • Thallium-201 stress- • Staged increase in redistribution- dobutamine starting reinjection at 5 μg/kg/min • Thallium-201 rest- redistribution • Nitrate-enhanced Tc- 99m perfusion imaging
  • 24.
    Patients randomized Patients with no Patients with no usable myocardial myocardial viability test viability test 594 611 Unusable test 1212 17 • Timing • Poor quality 618 601 Patients with Patients with usable myocardial myocardial viability test viability test
  • 25.
    Patients randomized inSTICH Revascularization Hypothesis 1212 SPECT Dobutamine echo n=471 n=280 321 150 130 Patients with no 611 usable myocardial viability test Patients with usable myocardial 601 viability test 114 Nonviable 487 Viable
  • 26.
    STICH Viability Results …demonstrate that association between myocardial viability and survival, is non- significant when subjected to a multivariable analysis that includes other baseline variables. …fail to demonstrate a significant interaction between myocardial viability and medical versus surgical treatment with respect to mortality, whether assessed according to treatment assigned (intention to treat) or to the treatment actually received.
  • 27.
    STICH Viability Implications: In patients with CAD and LV dysfunction, assessment of myocardial viability does not identify patients who will have the greatest survival benefit from adding CABG to aggressive medical therapy
  • 28.
    However, Limitations ofthe Trial Patients were selected for viability testing individually at the physicians' discretion Patients represent a subpopulation of STICH (<50%) The number of patients without substantial viability was small(114) which limited statistical power Use of two different imaging methods for assessing myocardial viability and their limitations of specificity/sensitivity. Analysis limited to SPECT and dobutamine echo, not PET or cardiac MRI while the analysis looked at "substantial viability" as an "all-or-none" variable, decisions whether to revascularize or not have generally depended on the extent of viability—that is, as a continuous variable.
  • 29.
    Take home message: Despiteall its imperfections the viability study suggests that assessment of myocardial viability alone may not be the deciding factor in selecting the best therapy for patients with ischemic heart disease and LV dysfunction. Besides viability one should also look at other factors like target vessels, LV volumes, EF etc. This is specially true if SPECT or Dobutamine echo only are used for viability testing. Whether they have viability or not, STICH like patients benefit from coronary bypass and we shouldn't be using viability studies such as these to exclude patients from cardiac surgery. We should await similar randomized studies with other methods of viability detection like MRI etc.
  • 30.
    Myocardial Viabilityand Mortality Myocardial Viability and Mortality 1.0 Variables associated with mortality Chi-square p Risk score Chi- p33.26 <0.001 0.8 square LV ejection fraction 24.80 <0.001 HR 95% Cl scoreP Risk LV EDVI 33.26 <0.001 35.36 <0.001 O.65 0.48 0.86 0.003 LV ESVI 24.80 LV ejection fraction <0.001 Mortality Rate LV EDVI 35.36 33.90 <0.001 <0.001 0.6 LV ESVI Myocardial viability 33.90 8.54 <0.001 0.003 Myocardial viability 8.54 0.003 0.4 50% 0.2 33% 0.0 0 1 2 3 4 5 6 Years from Randomization Without viability With viability
  • 31.
    Myocardial Viability andMortality Univariate Multivariable Variable No. Chi-square p value Chi-square p value SPECT and/or DE 601 8.54 0.003 1.57 0.210 SPECT alone 471 7.35 0.007 0.58 0.444 DE alone 280 1.18 0.277 0.42 0.518
  • 32.
    Myocardial Viability andCardiovascular Mortality Univariate Multivariable Chi-square p value Chi-square p value HR 95% Cl P 0.61 0.44 0.84 0.003 8.81 0.003 0.91 0.339
  • 33.
    Myocardial Viability andMortality + CV Hospitaliztion Univariate Multivariable Chi-square p value Chi-square p value 20.27 <0.001 8.60 0.003
  • 34.
    Patients with viabilitytests 601 Patients with Patients myocardial without viability 487 114 myocardial viability 243 244 60 54 MED CABG MED CABG 49.9% 50.1% 52.6% 47.4%
  • 35.
    Myocardial Viability andMortality 56% 35% 42% 31% Subgroup N Deaths HR 95% CI Interaction P value Without viability 114 58 0.70 0.41, 1.18 0.528 With viability 487 178 0.86 0.64, 1.16 0.25 0.5 1 2 CABG MED better better
  • 36.
    the patients without substantial viability, "who had perhaps less likelihood of functional recovery [than those with substantial viability], did as well from CABG as patients who did. . . . I think that's what we have to take away from this: we shouldn't be using [viability] studies to exclude patients from cardiac surgery -Dr Eric Velazquez
  • 37.
    Surgical Treatment forIschemic Heart Failure –STICH Trial In patients with HF, LVD < 35% and CAD amenable to CABG, CABG +MED will decrease all-cause mortality I compared to MED alone+ (Viability Substudy) Hypotheses In pts with dominant anterior wall LV II akinesia or dyskinesia, SVR + CABG + MED > hosp free survival compared with CABG + MED without SVR.
  • 38.
    For management ofpatients with HF with surgically revascularizable CAD and decreased LV function (1) Is contemporary CABG surgery superior to contemporary medical/secondary prevention therapy in prolonging survival in these pts? (2) Among patients with significant anterior wall dysfunction, does the addition of surgical ventricular reconstruction (SVR) to CABG improve hospitalization-free survival?
  • 39.
    Surgical Treatment forIschemic Heart Failure trial stratum and treatment assignment. CAD EF <= 0.35 SVR YES NO NO Medical SVR eligible? Not in trial eligibility eligible? NO YES YES Stratum A Stratum B Stratum C CABG + SVR MED CABG CABG + SVR CABG MED CABG
  • 40.
    Hypotheses : In patients with heart failure, left ventricular EF of 0.35 or less (1) coronary artery bypass grafting with intensive medical therapy improves long-term survival compared with survival with medical therapy alone, and (2) in patients with anterior left ventricular dysfunction, surgical ventricular reconstruction to a more normal left ventricular size plus coronary artery bypass grafting improves survival free of subsequent hospitalization for cardiac cause when compared with that with coronary artery bypass grafting alone.
  • 41.
    Major STICH hypotheses Primary Major secondary Hypotheses hypotheses H1 Coronary revascularization hypothesis Presence and extent of dysfunctional but viable ● Improvement in myocardial myocardium, as defined by perfusion by CABG combined radionuclide imaging, with MED improves long-term dobutamine stress survival compared with MED echocardiography, or both, alone. will identify patients with greatest survival advantage H2: LV restoration hypothesis of MED and CABG compared ● In patients with dominant anterior with MED alone. wall LV akinesia or dyskinesia, LV shape and size optimization by SVR combined with CABG and MED improves long-term survival free of cardiac hospitalization compared with CABG and MED without SVR.
  • 42.
    The conclusions thatcan be drawn from this substudy are limited by a number of factors  Viability data were not available for all the patients who were enrolled in the STICH main trial.3 The substudy patients represent slightly less than 50% of the randomized group. Furthermore, viability testing was not performed on a randomly selected subgroup of patients but, rather, was obtained according to test availability and the judgment of the recruiting investigator. Third, the possibility cannot be excluded that the results of viability testing could have influenced subsequent clinical decision-making
  • 43.
    Despite the goal of uniform testing in this trial, the nonrandom and nonblinded selection for viability testing of only 601 of the 1212 eligible patients (49.6%) introduces considerable biases. Moreover, viability was defined in a binary fashion, and revascularization was not guided by the presence of viable myocardium within specific coronary- artery territories. In addition, the study is underpowered in the group with nonviable myocardium (i.e., 60 patients who received medical therapy and 54 patients who underwent CABG). Finally, viability assessment was restricted to single- photon-emission computed tomography (SPECT) and dobutamine echocardiography, which have well-known limitations in their ability to detect viability.1 We believe there is need for a randomized study of revascularization versus medical therapy after viability assessment with a standard technique such as contrast-enhanced magnetic resonance imaging (MRI) or positron-emission tomography (PET),1-3 which would allow targeted revascularization based on the presence of viable myocardium within specific coronary-artery territor
  • 44.
    "The analysis of intention-to-treat vs actual treatment is interesting, but the biological effect that our patients feel is what treatment they receive, and under that analysis, as a surgeon, you must conclude that patients with left ventricular dysfunction should receive coronary bypass." - Dr Steven Bolling (University of Michigan Cardiovascular Center, Ann Arbor)
  • 45.
    Study Design  Randomized controlled trial, non-blinded  99 clinical sites in 22 countries  Investigator-initiated and led  National Heart, Lung and Blood Institute funded  Duke Clinical Research Institute managed  Independent Data and Safety Monitoring Committee  Clinical Events Adjudication Committee  Blinded Core Laboratories
  • 46.
    Endpoints Primary Endpoint – All-cause mortality Major Secondary Endpoints – Cardiovascular mortality – Death (all-cause) + cardiovascular hospitalization
  • 47.
    Important Inclusion Criteria LVEF ≤ 0.35 within 3 months of trial entry  CAD suitable for CABG  MED eligible – Absence of left main CAD as defined by an intraluminal stenosis of ≥ 50% – Absence of CCS III angina or greater (angina markedly limiting ordinary activity)
  • 48.
    Major Exclusion Criteria  Recent acute MI (within 30 days)  Cardiogenic shock (within 72 hours of randomization)  Plan for percutaneous intervention  Aortic valve disease requiring valve repair or replacement  History of more than 1 prior CABG  Non-cardiac illness with a life expectancy of less than 3 years or imposing substantial operative mortality
  • 49.
    Surgical Treatment forIschemic Heart Failure trial stratum and treatment assignment. CAD EF <= + CABG amenable 0.35 SVR YES NO SVR NO Medical eligible? eligible? Not in trial eligibility NO YES YES Stratum A Stratum B Stratum C CABG + SVR MED CABG CABG + SVR CABG MED CABG
  • 50.
    STICH Viability • Allrandomized patients were eligible for viability testing with SPECT myocardial perfusion imaging or dobutamine echo. • Viability testing was optional at enrolling sites and was not a prerequisite for enrollment.
  • 51.
    STICH Viability Criteria formyocardial viability were prospective and pre- specified SPECT: • 17 segment model • ≥11 segments manifesting viability based on relative tracer activity Dobutamine echo: • 16 segment model • ≥5 segments with dysfunction at rest manifesting contractile reserve with dobutamine
  • 52.
    STICH Viability  Primaryendpoint: ▪ All-cause mortality Secondary endpoints: ▪ Mortality plus cardiovascular hospitalization ▪ Cardiovascular mortality Intention-to-treat analysis
  • 53.
    Baseline Characteristics Patients Withand Without Myocardial Viability Viable Non-Viable Variable (n=487) (n=114) P value Age 61 ± 10 61 ± 9 NS Multivessel CAD 73% 73% NS Proximal LAD stenosis 64% 70% NS Risk score* 12.4 ± 8.7 12.9 ± 9.3 NS Previous MI 76.6% 94.7% <0.001 LV ejection fraction (percent) 28 ± 8 23 ± 9 <0.001 LV end-diastolic volume index (ml/m2* ) 117 ± 37 147 ± 53 <0.001 LV end-systolic volume index (ml/m2) 86 ± 33 116 ± 50 <0.001 Significant covariates in risk model: Age, renal function, heart failure, ejection fraction, CAD index, mitral regurgitation, stroke
  • 54.
    Background • LV dysfunctionin patients with CAD is not always an irreversible process, as LV function may improve substantially after CABG • Assessment of myocardial viability is often used to predict improvement in LV function after CABG and improvement in survival
  • 55.

Editor's Notes

  • #10 Difference statistically significant after allowing for baseline differences Model 3 Covariate adjusted – all variables prospectively specified in STICH protocol or with significant prognostic effect. Stratum, age, gender, race, HF class at baseline, MI history, previous revascularization, best available EF, number of diseased vessels, chronic renal insufficiency, MR, stroke hx, AF hxHR 0.83 (0.68, 0.99) p = 0.039.
  • #16 Need to convert this into HR plot
  • #21 Nejm editorial on stich
  • #31 HR 95% Cl PO.65 0.48 0.86 0.003