Elassy SM

Research Article

Austin Cardio & Cardiovasc Case Rep. 2016; 1(1): 1005.

Impact of Previous Stenting on the Outcome of CABG in Multivessel Disease

Elassy SM*

Department of Cardiothoracic Surgery, Ain Shams University, Cairo, Egypt

*Corresponding author: Elassy SM, Department of Cardiothoracic Surgery, Ain Shams University, Cairo, Egypt

Received: December 01, 2015; Accepted: January 27, 2016; Published: January 29, 2016

Abstract

Aim of the Study: To determine if previous coronary stenting has an impact on the outcome of subsequent CABG.

Patients and Methods: Between May 2009 and January 2011, 200 patients who were candidate for CABG, where prospectively divided into two groups Group I had previous PCI (n = 100, mean age 57.20 ± 8.52 years, 9 women) and group II (n = 100, mean age 53.25 ± 7.95, 18 women) had no prior PCI. Group I patients presented with higher incidence previous MI (p value=0.001) and higher mean NYHA class (P = 0.012).

Results: In Group II there was higher mean total number of grafts (P value=0.001), higher incidence of total revascularization (P value=0.001), respectively. In Group I there was a higher incidence of inotropic support usage (P value = 0.001), incidence of arrhythmias (P value = 0.026), incidence of bleeding (P value = 0.002), wound infection (P value = 0.002) and the mean hospital stay (P value = 0.001). Postoperative echo after 3 months showed, more improved parameters of myocardial function in Group I, as evidence by statistically significant more decrease in LVEDD (P<0.001) and LVESD (P=0.015), a significant more improvement in LV paradoxical motion (P<0.001) as well as a non-significant improvement in LVEF %.

Conclusion: Prior PCI increases the morbidity and reduces the improvement of cardiac function after subsequent CABG in multivessel disease patients.

Keywords: Multivessel disease; Stenting

Introduction

Since the introduction of Percutaneous Coronary Intervention (PCI) for treatment of Coronary Artery Disease (CAD), there has been a shift from its primary indication for single isolated single vessel lesion to multivessel disease. [1] Moreover with increased experience, aggressive repeated PCI therapy has become more common. Results from randomized controlled trials and registries comparing PCI and Coronary Artery Bypass Graft (CABG) have shown that PCI is inferior to CABG as regards the need for repeat revascularization and recurrence of angina particularly in patients with diabetes mellitus and complex triple-vessel disease even in the era of Drug Eluting Stents (DES). [2,3,4,5,6,7] Combining the previous facts, will conclude that there is an increasing number of patients with multivessel or triple-vessel disease in whom PCI is initially performed before subsequent CABG. There is some evidence that previous PCI has a negative impact on subsequent CABG [8,9,10], however this topic needs further investigations especially on the impact of PCI on the complexity of coronary disease. We therefore sought to determine whether previous PCI has a prognostic impact on surgical outcome of subsequent CABG.

Material and Methods

This study included 100 patients who benefited from CABG after successful primary PCI (group A) and 100 patients who benefited from primary CABG (group B) at Eldemardash hospital, Ain shams specialized hospital and National heart institute, in the period between May 2009 and January 2011. In group A, 46 patients benefited from bare metal stent and 54 patients benefited from DES. The number of implanted stents varied from 1 to 5 (1.89 + 0.8 stents), with 36 patients benefited from 1 stent, 45 patients benefited from 2 stents, 16 patients from 3 stents, 2 from 4 stents and only 1 patient benefited from 5 stents. Common to both groups, our inclusion criteria were: patients’ age between 40 and 70 years, of both sexes, undergoing CABG for multi-vessel disease, with or without the need for surgery for ischemic mitral valve disease. Redo cases, cases presenting with organic valvular heart disease, patients undergoing CABG for single vessel diseases well as those patients needing emergency CABG after failure of PCI were excluded from this study.

As shown in (Table 1), patients’ demographic criteria and risk factors were comparable between both groups, with the exception of group A patients being significantly younger and including more females; compared to group B patients. However, patients with primary PCI presented in a more significantly advanced NYHA class, included significantly more patients with previous MI and a nonsignificant higher proportion of left main disease. On the other hand, group B patients had significantly higher proportion of peripheral arterial disease, compared to patients in group A. Angiograms were scored according to the SYNTAX score algorithm (www.syntaxscore. com) [11] by the Angiographic Core Laboratory (Cardialysis BV, Rotterdam, The Netherlands). Although SYNTAX score is statistically comparable in both groups preoperatively, the mean SYNTAX score in group A has increased from 10.96±6.28in angiograms before PCI to 18.8±7.2 in angiograms before CABG. Also, it worth mentioning that when comparing pre PCI and pre CABG SYNTAX score, we have noticed that 20 patients have moved from low score category to intermediate and high score category after PCI (Table 2).

Table 1: Comparison of preoperative variables between both groups: Group A undergoing primary CABG and group B undergoing CABG after PCI.




  
     
    Patient groups
    P value^*
  
  
    A
      (100 patients)
    B
      (100 patients)
  
  
    Age (years)
    52.9+ 7.6
    57.2+ 8.5
    0.001
  
  
    Female sex
    27
    10
    0.002
  
  
    DM
    59
    61
    NS
  
  
    Hypertension
    37
    27
    NS
  
  
    Dyslipidemia
    39
    47
    NS
  
  
    Smokers
    49
    49
    NS
  
  
    Family history of ischemic heart disease
    15
    10
    NS
  
  
    Previous MI
    68
    24
    0.001
  
  
    RecentMI
    6
    7
    NS
  
  
    Previous HF
    0
    2
    NS
  
  
    Left main disease
    19
    11
    NS
  
  
    Syntax score
    18.8 + 7.2
    20.68 + 7.6
    NS
  
  
    Euro score
    2.1 + 2.2
    2.8 + 5.4
    NS
  
  
    Preoperative Shock
    2
    0
    NS
  
  
    UnstableAngina
    13
    14
    NS
  
  
    Number of diseased vessels
    3.3 + 0.5
    3.5 + 0.5
    NS
  
  
    Ischemic MR
    37
    40
    NS
  
  
    NYHA FC
    1.86 + 0.94
    1.55 + 0.88
    0.012
  
  
    CCS FC
    2.2 + 0.85
    2.15 + 1.1
    NS
  
  
    Chronic renal impairment
    7
    2
    NS
  
  
    COPD
    9
    10
    NS
  
  
    Pulmonary hypertension
    5
    1
    NS
  
  
    Peripheral arteriopathies
    6
    16
    0.027
  
  
    Values are presented as numbers (%) or mean + SD. ^*=    Chi-Square test / Fisher’s exact test or unpaired Student’s test, as    indicated.



Table 1:  Comparison of preoperative variables between both groups: Group A
undergoing primary CABG and group B undergoing CABG after PCI.

Table 2: Number of patients in each category of SYNTAX score in both groups: Group A undergoing primary CABG and group B undergoing CABG after PCI.




  
    Syntax score
    Group A
    Group B 
  
  
    Pre stent
      (100 patients)
    Preoperative
      (100 patients)
    Preoperative
      (100 patients)
  
  
    Low    (0-22)
    92
    72
    63
  
  
    Intermediate    (22-32)
    8
    24
    29
  
  
    High    (>32)
    0
    4
    8
  
  
    Values are    presented as numbers.



Table 2:  Number of patients in each category of SYNTAX score in both groups:
Group A undergoing primary CABG and group B undergoing CABG after PCI.

An echo was done within one month preoperatively, before discharge and 3 months after the operation. (Table 3) shows the preoperative echocardiographic data, with group a patients showing significantly larger LVEDD, compared to group B patients. Other echocardiographic data; including LVESD, EF% and LV systolic wall motion abnormality were comparable between the 2 groups.

Table 3: Comparison of echocardiographic data between both groups: Group A undergoing primary CABG and group B undergoing CABG after PCI.




  
     
    Patient groups
    P value^*
  
  
    A
      (100 patients)
    B
      (100 patients)
  
  
    LV ESD (cm)
      1) Preoperative
      2) Postoperative
      3) Mean of the difference
     
      3.66 + 0.8
      3.5 + 0.76
      0.12 + 0.57
     
      3.86 + 0.95
      3.45 + 0.75
      0.34 + 0.64
     
      NS
      NS
      0.015
  
  
    LVEDD (cm)
      1) Preoperative
      2) Postoperative
      3) Mean of the difference
     
      5.2 + 6.5
      5.1 + 0.65
      0.11 + 0.6
     
      4.95 + 0.9
      4.45 + 0.98
      0.48 + 0.67
     
      0.21
      0.001
      0.001
  
  
    EF%
      1) Preoperative
      2) Postoperative
      3) Mean of the difference
     
      57 + 9.1
      58.3 + 7
      1.32 + 6.8
     
      54.57 + 11.3
      60 + 5.67
      4.1 + 9.1
     
      NS
      NS
      NS
  
  
    Paradoxical systolic motion
      1)Preoperative
      2)Postoperative
     
      58
      44
     
      45
      16
     
      NS
      0.001^**
  
  
    Values are presented as numbers (%) or mean + SD. ^*=    Chi-Square test / Fisher’s exact test or unpaired Student’s test, as    indicated, ^** = McNemar test.



Table 3:  Comparison of echocardiographic data between both groups: Group A
undergoing primary CABG and group B undergoing CABG after PCI.

According to the surgeon’s preference, patients were either operated with OPCAB with ACROBAT™ Mechanical Stabilizer System or under routine CPB with mild hypothermia and repeated infusions of antegrade warm blood cardioplegia. In all patients, the Left internal mammary artery was used to graft an Omni present LAD lesion. Total arterial revascularization was attempted whenever feasible, with the use of the right internal mammary artery and/ or radial artery of the non-dominant hand; otherwise additional coronary lesions were grafted with a suitable venous conduit. Patients with grade 3-4 ischemic mitral regurge were planned to benefit from mitral valve repair. Operative and postoperative data are presented in (Table 4).

Table 4: Comparison of operative and postoperative variables between both groups: Group A undergoing primary CABG and group B undergoing CABG after PCI.




  
     
    Patient groups
     
      P value^*
  
  
    A
      (100 patients)
    B
      (100 patients)
  
  
    Number of grafts:
      a) Number of    arterial grafts
      b) Number of venous    grafts
    2.47 +0.85
      1.07 + 0.3
      1.39 + 0.9
    3.12 + 0.73
      1.24 + 0.5
      1.89 + 0.7
    0.001
      0.001
      0.001
  
  
    Total revascularization
    79 (79%)
    50 (50%)
    0.001
  
  
    Total arterial revascularization
    18 (18%)
    1 (1%)
    0.001
  
  
    Mitral valve repair for ischemic MR
    0
    4
    NS
  
  
    Surgical technique:
      1) OPCAB
      2) CPB
     
      35
      65
     
      27
      73
     
       
      NS
  
  
    ACC time (minutes)
    62.7 + 28.1
    68.7 + 25.6
    NS
  
  
    CPB time (minutes)
    91.2 +42.6
    102.1 +33.8
    NS
  
  
    PerioperativeMI
    18
    17
    NS
  
  
    Use of positive inotropes
    62
    40
    0.001
  
  
    Use of IABP
    13
    11
    NS
  
  
    Duration of mechanical ventilation
    13.2 + 12.7
    10.24 + 11.9
    NS
  
  
    Arrhythmias
    21
    10
    0.026
  
  
    Postoperative heart failure
    11
    13
    NS
  
  
    Neurologicalcomplications
    2
    1
    NS
  
  
    Renal impairment
    7
    2
    NS
  
  
    Endocarditis
    0
    2
    NS
  
  
    ICU stay (days)
    2.9 + 1.44
    3.4 + 4.5
    NS
  
  
    Death
    6
    7
    NS
  
  
    Exploration
    25
    9
    0.002
  
  
    Endocarditis
    0
    2
    NS
  
  
    Dehiscent sternum
    5
    10
    NS
  
  
    Superficial wound infection
    35
    18
    0.004
  
  
    Deep wound infection
    15
    3
    0.002
  
  
    Organ failure
    2
    2
    NS
  
  
    Hospital stay (days)
    11.3 + 3.8
    9.3 + 3.8
    0.001
  
  
    Values are presented as numbers (%) or mean + SD. ^*=    Chi-Square test / Fisher’s exact test or unpaired Student’s test, as    indicated.



Table 4:  Comparison of operative and postoperative variables between both
groups: Group A undergoing primary CABG and group B undergoing CABG after
PCI.

Statistical analysis: Data are presented as number (%) or mean + SD. The distribution of categorical data was compared with Chi- Square test or Fisher’s exact test, as indicated. Means were compared with unpaired Student’s test, as indicated. The means of the differences of recorded echocardiographic data (LVEDD, LVESD and EF %) were compared using unpaired Student test too. On the other hand, amelioration of LV systolic wall motion abnormality after surgery was compared in the 2 groups using the non-parametric McNemar test. A P value of <0.05 was considered as a limit of statistical significance. SPSS 19 statistical package was used for data analysis.

Results

As shown in (Table 4), and compared to group A, Group B patients benefited from significantly larger number of grafts, total revascularization as defined by grafting all stenotic vessels greater than 1.5 mm and/or all stenotic main-branch vessels, was achieved in only 129 patients (64.5%): 79 patients in group A (79%) and 50 patients in group B (50 %; P<0.001). Also, total arterial revascularization was achieved in 19 cases (9.5%): 18 patients in group A (18%) and 1 patient in group B (1%; P<0.001). In addition, 4 patients with grade 3-4 mitral regurge benefited from annuloplasty using Mitral annuloplasty ring (Carpentier-Edwards Classic) (Edwards Life sciences, Irvine, Calif.) size 28 mm. In group A, more patients needed positive inotropic support, were re-explored for bleeding, developed superficial as well as deep wound infection, stayed for longer time in hospital and suffered from more incidences of arrhythmias compared to group B patients. Other operative and postoperative variables, including mortality and other morbidity figures were comparable between both groups of patients (Table 3).

As shown in (Table 3), parameters of myocardial function were more improved in group A patients, as evidenced by statistically significant more decrease in LVEDD (P<0.001) and LVESD(P=0.015), a significant more improvement in LV paradoxical motion as well as a non-significant improvement in LVEF%, compared to group B patients (Table 3).

Discussion

PCI is often preferred over CABG for its “less invasiveness” especially when bothprocedures are justified.This choice is reinforced by the belief that patients can bereferred to surgery after PCI without a negative impact on subsequent CABG. However there is now cumulating evidence thatprior PCI has a negative impact on subsequent CABG. It is associated with a higher early mortality [12,13] morbidity [12] and MACE rate [9,11,14] with impaired longterm outcome and quality of life [9] and with more unstable angina requiring hospitalization and repeated coronary revascularization during follow-up [8]. Also it has been found to be associated with increased mortality and morbidity and reduced 2 years survival in diabetic patients. [15]

In the current study, although patients with previous PCI appears to have more advanced disease as evidenced by advanced NYHA class and more previous MI, all parameters of myocardial function were more improved after surgery in patients who underwent CABG without previous stenting. The operative results showed less total and arterial revascularization in previous PCI patients. Also, the postoperative outcome in the stent group was inferior to patients who underwent CABG without previous PCI as evidenced by higher rate of overall morbidity, usage of inotropes, arrhythmias, reoperation for bleeding and wound infection. The hospital stay was also significantly higher in stent group. However, our results showed similar rates of in-hospital mortality between the two groups.

Although statistical correlation does not imply causation, yet there are several rational hypotheses to explain the results. Periprocedural infarction during previous PCI [16] may be the cause for higher incidence of preoperative MI and preoperative higher NYHA class in the stent group. PCI procedures initiate a sequence of local inflammatory reactions which lead to poor targets for grafting this may explainless total revascularization and less number of grafts in the stent group [17]. Coagulopathy from adjunctive anti-platelet therapy especially after DES may explain higher incidence of reexploration for bleeding in Group A [18]. There are other explanations to explain negative impact of stents on CABG as grafts being performed more distally due to the presence of stents (9), instant rest enosis is associated with a higher risk of early venous graft failure [19], post stenting structural changes affecting the stented area and the coronary artery section distal to the stent which would be the target area of a subsequent bypass graftanastomosis [17]. These explanations are summarized and classified into intrinsic pathophysiology, acquired pathophysiology and technical squeal by Rao and colleagues [20].

To our knowledge this is the first study to use SYNTAX score in comparing the complexity of coronary disease between patients who underwent CABG without previous stenting and with previous stenting. Although there were no statistical differences between the two groups preoperatively the results showed that after PCI patients where shifted to the intermediate and high risk score categories which means that when patients are referred for surgery after PCI they seems to have a more complex coronary disease and this might be one of the reasons for negative outcome of PCI on subsequent CABG. Moreover, this negative impact is more manifested with DES.

DES use is associated with increased risks of both early and late stent thrombosis, as well as death and MI [21]. DES impair endothelialization, leaving a potentially prothrombotic substrate within the vessel [22] and leave a further conflict for the surgeon in terms of control of ant platelet medication and whether to perform bypass grafts to a coronary vessel with a DES without critical rest enosis in patients who have multi vessel disease [23]. In our study Group A patients included patients who had DES but in further study BMS could be compared with DES regarding their impact on subsequent CABG.

Although, we have not compared cost in our study, the fore mentioned clinical concerns are compounded by cost implications; not only are DES significantly more expensive than BMS, but new recommendations that patients remain on clopidogrel for at least a year, and possibly indefinitely, add significantly to overall costs [23].

The conclusion from the findings that prior PCI increases the risk of subsequent CABG is to add to the supply of data against the false belief that CABG can always be safely postponed after an initial PCI in multivessel disease and any cardiac intervention especially in multi vessel disease should be discussed by a multidisciplinary team including a surgeon rather than by the individual cardiologist.

Study Limitations

This study has several limitations. It has been designed as a consecutive, observational, multicenter investigation. The number of enrolled patients limits the explanatory power o four study. Selection of patients of both groups may introduce an underlying bias. Finally we limited our analysis to short-term outcomes.

Conclusion

Prior PCI increases the morbidity and reduces the improvement of cardiac function after subsequent CABG in multivessel disease patients.

References

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Citation: Elassy SM. Impact of Previous Stenting on the Outcome of CABG in Multivessel Disease. Austin Cardio & Cardiovasc Case Rep. 2016; 1(1): 1005.

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