A QUANTIFICATION AND IMPACT OF INCOMPLETE REVASCULARIZATION USING RESIDUAL SYNTAX SCORE IN NSTEMI PATIENTS AFTER PERCUTANEOUS CORONARY INTERVENTION

Abstract

Objectives: The aim of this study was to assess the prognostic significance of rSS after PCI for NSTEMI in terms of all-cause mortality and MACE (Major adverse cardiac event) at 3 years of follow-up.

Methodology: A retrospective analysis of 115 consecutive NSTEMI patients who underwent PCI at the Aga Khan University Hospital Karachi between January 2016 and December 2016 was performed. 7 patients were excluded from the final analysis due to missing data (n=108). The SYNTAX scores before (baseline syntax=bSS) and after PCI (rSS) were calculated. Patients were stratified as CR if rSS =0, RICR if rSS >0 and ≤8 and ICR if rSS >8.

Results: Patients that achieved CR were 44 (40.7%), RICR were 40 (37.7%) and ICR were 24 (22.2%). After three-year follow-up, ICR patients had the highest incidence of both all-cause mortality [(CR) 4.5% vs. (RICR) 5% vs. (ICR) 37.5% respectively; p<0.001] and major adverse cardiovascular (MACE) defined as composite of follow up cardiac death, MI and revascularization [(CR) 5% vs. (RICR) 10% vs. (ICR) 50% respectively; p<0.001]. There was no difference in the incidence of all-cause death (4.5% vs. 5%; p=0.92) or MACE (4.5% vs 10%, p=0.332) in patients with CR and ICR respectively (Table 1).

Table 1: Outcomes at two years of follow-up according to residual SYNTAX score

MACE- Major Adverse cardiac event (Cardiac death,MI or Revascularisation); CR- complete revascularization; RICR- Reasonable incomplete revascularization; ICR- Incomplete revascularization

CR (rSS=0)

N= 44

RICR (rSS >0 and ≤8)

N= 40

ICR (rSS>8)

N= 24

P value

CR vs RICR

p value

CR vs ICR

P value

RICR vs ICR

P value

All cause death

2 (4.5)

2 (5)

9 (37.5)

<0.001

0.92

<0.001

0.001

Cardiac death

1 (2.3)

2 (5)

7 (29.2)

0.001

0.50

0.001

0.007

MI

1 (2.3)

1 (2.5)

8 (33.3)

<0.001

0.949

<0.001

0.001

Revascularization

1 (2.3)

3 (7.5)

3 (12.5)

0.25

0.261

0.087

0.51

MACE

2 (4.5)

4 (10)

12 (50)

<0.001

0.332

<0.001

<0.001

Conclusion: The residual SYNTAX score (rSS) is a useful tool in quantifying incomplete revascularization in patients undergoing PCI for NSTEMI. ICR appears to confer a higher three-year mortality and MACE, however outcomes for RICR and CR were comparable. Hence the calculation of rSS in daily practice may also be used to determine a reasonable level of revascularization in patients where complete revascularization may not be possible.