SMart Angioplasty Research Team-Optimal STRATEGY for Provisional Side Branch Intervention in Coronary Bifurcation Lesions - SMART-STRATEGY

Mar 21, 2016
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Author/Summarized by Author:
Anthony A. Bavry, MD,MPH,FACC
Summary Reviewer:
Deepak L. Bhatt, MD, MPH, MBA, FACC
Trial Sponsor:
Sungkyunkwan University Foundation for Corporate Collaboration
Date Published:
03/21/2016
Original Posted Date:
03/21/2016
References

Description:

The goal of the trial was to evaluate a conservative strategy versus an aggressive strategy for provisional treatment of a side branch coronary artery.

Contribution to the Literature: The SMART-STRATEGY trial showed that a conservative approach to treating the side branch is superior to a more aggressive approach.

Study Design

  • Randomized
  • Parallel
  • Stratified

Patients with a bifurcation coronary lesion were randomized to a conservative strategy (n = 128) versus an aggressive strategy (n = 130) for provisional treatment of side branch coronary arteries.

Left main lesions:

  • Conservative approach defined as side branch ballooning only if >75% stenosis, followed by side branch stenting only if residual stenosis >50% or dissection
  • Aggressive approach defined as side branch ballooning only if >50% stenosis, followed by side branch stenting only if residual stenosis >30% or dissection

Non-left main lesions:

  • Conservative approach defined as side branch ballooning only if < Thrombolysis in Myocardial Infarction (TIMI) 3 flow in the side branch, followed by side branch stenting only if residual TIMI 3 flow in the side branch
  • Aggressive approach defined as side branch ballooning only if >75% stenosis, followed by side branch stenting only if residual stenosis >50% or dissection

  • Total number of enrollees: 258
  • Duration of follow-up: 3 years
  • Mean patient age: 62 years
  • Percentage female: 18%
  • Percentage diabetics: 29%

Inclusion criteria:

  • Stable coronary artery disease or non-ST-elevation acute coronary syndrome
  • Main vessel diameter ≥2.5 mm
  • Side branch diameter ≥2.3 mm

Exclusion criteria:

  • Hemodynamic instability
  • Left ventricular ejection fraction <25%
  • Primary percutaneous coronary intervention

Other salient features/characteristics:

  • Left main lesions: 45%
  • Non-left main lesions: 55%

In the conservative group, balloon inflation of the side branch occurred in 26%, while stent implantation of the side branch occurred in 7%.

In the aggressive group, balloon inflation of the side branch occurred in 69%, while stent implantation of the side branch occurred in 30%.

Principal Findings:

The primary outcome of target vessel failure (TVF) defined as cardiac death, spontaneous MI, or target vessel revascularization (TVR) at 1 year occurred in 9.4% of the conservative group versus 9.2% of the aggressive group (p = 0.97).

Secondary outcomes:

  • TVF at 3 years: 11.7% of the conservative group vs. 20.8% of the aggressive group (p = 0.049)
  • Cardiac death or MI at 3 years: 0.8% of the conservative group vs. 6.2% of the aggressive group (p = 0.036)
  • Cardiac death at 1-3 years: 1 in the conservative group vs. 3 in the aggressive group (p = 0.62)
  • MI at 1-3 years: 0 in the conservative group vs. 4 in the aggressive group (p = 0.12)
  • TVR at 1-3 years: 2 in the conservative group vs. 10 in the aggressive group (p = 0.02)
  • Target lesion revascularization (TLR) for main branch at 1-3 years: 0 in the conservative group vs. 8 in the aggressive group (p = 0.007)

Interpretation:

Among individuals with a bifurcation coronary lesion, a conservative approach to provisionally treat the side branch was superior to an aggressive approach. Although there was no difference between these strategies at 1 year, there were greater numbers (individually) of cardiac death, MI, and TVR between 1 and 3 years in the aggressive group. The difference in TVR was mainly due to a significant increase in main vessel TLR in the aggressive group. Overall, there was a lower frequency of TVF at 3 years from a conservative approach. These results apply to both left main and non-left main bifurcation lesions.

A conservative approach resulted in fewer balloon inflations and stent implantations in the side branch. Possible reasons for late harm include stent deformation from kissing balloon inflation and/or overlapping stent struts. These results support a high threshold to treat jailed side branch arteries.

References:

Song YB, Park TK, Hahn JY, et al. Optimal Strategy for Provisional Side Branch Intervention in Coronary Bifurcation Lesions: 3-Year Outcomes of the SMART-STRATEGY Randomized Trial. JACC Cardiovasc Interv 2016; 9:517-26.

Clinical Topics: Acute Coronary Syndromes, Cardiovascular Care Team, Invasive Cardiovascular Angiography and Intervention, Atherosclerotic Disease (CAD/PAD), Interventions and ACS, Interventions and Coronary Artery Disease

Keywords: Angioplasty, Angioplasty, Balloon, Acute Coronary Syndrome, Constriction, Pathologic, Coronary Artery Disease, Death, Myocardial Infarction, Myocardial Ischemia, Stents


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