Which One Should be Treated in the Setting of Acute ST Elevation Myocardial Infarction - Culprit Lesion or Culprit Vessel?
Condition: Myocardial Infarction
MeSH terms: Myocardial Infarction; Infarction
Study type: Observational

Summary: 
      The current guidelines still recommend emergent PCI of the culprit lesion and state that
      primary PCI should be limited to the culprit vessel with the exception of cardiogenic shock
      and persistent ischaemia after PCI of the supposed culprit lesion. This recommendation is
      based on a high number of studies. However, several studies are present about the safety and
      efficacy of non-culprit vessel PCI during acute MI. Nowadays, the debate is increasingly
      going on about the PCI of the non-culprit arteries during the index event with newer
      prospective randomized studies. Besides, it is still unclear for the culprit artery whether
      to treat only the culprit lesion or all the other lesions in the culprit vessel during the
      index event. The present report describes a retrospective comparison between the two
      strategies during primary PCI for STEMI, looking for their influence on the clinical and
      angiographic course of the patients.
    

Detailed description: 
      Patient selection: This multi-centre retrospective study included patients from 3 high-volume
      primary PCI centres in Turkey. A total number of 5512 patients underwent emergent PCI for
      acute STEMI between January 2011 and December 2013. From this patient population, patients
      were looked for the presence of an additional lesion to the culprit lesion (CL). Additional
      lesion was defined as the presence of an angiographically severe (≥70%) lesion other than the
      CL either proximal or distal to it in the same coronary artery after the distal flow was
      observed most commonly as a result of guide-wire passage or PTCA of the total occlusion.

      Exclusion criteria: - Presence of LMCA lesion

        -  Cardiogenic shock

        -  Previous CABG operation

        -  Decision for CABG operation after primary PCI

        -  Severe valvular disease including aortic stenosis of mitral insufficiency

        -  Severe kidney disease (serum creatinine >2.5 mg/dl or patients on maintenance
           hemodialysis)

        -  Rejection of second PCI by the patient after the index event

      The eligible patients were retrospectively sought from the database of the relevant hospital.
      The basal characteristics of the patients like age, sex, presence of coronary risk factors
      (smoking, hypertension, diabetes mellitus and hyperlipidemia), vital signs and location of
      STEMI at admission were noted. The emergent coronary angiograms of the patients were then
      examined and several angiographic and post-PCI features which are defined in detail in the
      following sections were addressed. Follow-up of these patients were succeeded either by phone
      call, routine polyclinic visits or from the database of hospital.

      Study groups: Patients were grouped into 2 according to the PCI strategy; culprit vessel (CV)
      group including patients who underwent emergent PCI of all severe (≥70 stenosis in CAG)
      lesions in the culprit vessel and culprit lesion (CL) group including patients who underwent
      emergency PCI only for the CL and staged PCI in 2 weeks for the other additional lesions in
      the CV. Both groups underwent staged PCI for the severe lesion(s) in non-culprit vessel(s) if
      necessary in a different session in 28 days after the index event. Staged PCI was the
      preferred strategy in both groups if necessary because staged PCI has been found to be at
      least non-inferior to other strategies in several studies [3, 4, 10, 13].

      Definition of acute STEMI: The criteria for diagnosis of STEMI were: (1) chest pain within 24
      h before admission that lasted for more than 30 min and was not relieved by sublingual
      nitroglycerin; (2) ST-segment elevation on electrocardiogram; and (3) elevated serum creatine
      kinase (CK) or troponin levels.

      Emergent coronary angiography and PCI procedure: All patients were routinely treated with
      heparin, clopidogrel, aspirin, statin and an angiotensin converting enzyme inhibitor or
      angiotensin II receptor blocker unless contraindicated.

      Coronary angioplasty and stent implantation were performed according to standard percutaneous
      techniques through the femoral artery. Standard selective coronary angiography with at least
      4 views of the left coronary system and 2 views of the right coronary artery was performed
      using the Judgkins technique.

      All the patients with the diagnosis of acute STEMI underwent emergent PCI with bare metal or
      drug-eluting stents. Stent implantation was performed at an inflation pressure of 10 to 16
      atm. When suboptimal stent deployment was observed, angiographic optimization was performed
      using high-pressure noncompliant balloon dilatation to achieve <20% residual stenosis by
      visual estimation. Angiographic no-reflow phenomenon was diagnosed if a significant coronary
      flow decrease (Thrombolysis In Myocardial Infarction [TIMI] grade <3 flow) without mechanical
      obstruction was noticed in final cineangiograms obtained at completion of the PCI procedure
      [14, 15].

      Staged PCI: Staged PCI procedure was performed either to the culprit vessel in CL group
      and/or to the non-culprit lesion(s) in non-culprit vessel(s) in both groups in 14 days after
      the index event. In the CL group, it was performed to culprit and non-culprit vessels during
      same intervention. In the CV group, it was performed to non-culprit vessels if necessary.

      Follow-up of patients: The investigators collected follow-up information from the database of
      the hospitals and/or during telephone calls with patients. Follow-up included screening for
      major outcomes including death (in-hospital, cardiac and non-cardiac), non-fatal myocardial
      infarction, and need for surgical or percutaneous revas¬cularisation.

      Myocardial infarction was defined as a troponin level above the 99th percentile and symptoms
      of cardiac ischemia. For patients with re-infarction, the definition required ≥20% increase
      of cardiac markers (Troponin) with ischemic symptoms or ECG findings or angiographic evidence
      of coronary artery occlusion including early stent thrombosis. Early stent thrombosis was
      defined as acute myocardial infarction due to stent thrombosis in 30 days after implantation,
      usually during index hospitalization.

      Statistical analysis: The analysis of the results was performed using the Predictive
      Analytics SoftWare (PASW) Statistics 18.0 for Windows (Statistical Package for the Social
      Sciences, SPSS Inc., Chicago, Illinois). Data were tested for a normal distribution using the
      Kolmogorov-Smirnov test. The categorical variables were shown as numbers of cases with
      percentages and the normally distributed continuous variables were shown as mean ± SD.
      Student's t-test was used for the analysis of the continuous variables that were normally
      distributed and the χ2 test for the categorical variables. The Kruskal-Wallis rank-sum test
      was used for the variables that were not normally distributed. Statistical significance was
      defined as p value less than 0.05.
    

Intervention name(s): Primary PCI
Intervention type(s): Procedure
Observational model: Cohort
Time perspective: Retrospective
Sampling method: Non-Probability Sample
Study population: 
        This multi-centre retrospective study included patients from 3 high-volume primary PCI
        centres in Turkey. A total number of 5512 patients underwent emergent PCI for acute STEMI
        between January 2011 and December 2013. From this patient population, patients were looked
        for the presence of an additional lesion to the culprit lesion (CL). Additional lesion was
        defined as the presence of an angiographically severe (≥70%) lesion other than the CL
        either proximal or distal to it in the same coronary artery after the distal flow was
        observed most commonly as a result of guide-wire passage or PTCA of the total occlusion.
      
Keywords: myocardial infarction; TIMI flow; culprit lesion; culprit vessel