2.3 Statistical Analysis
The statistical analysis was performed using the SPSS version 21
program. Variables were presented as number and percentage or as mean ±
standard deviation for discrete and continuous variables respectively. A
two-sample t-test test was used for continuous data, and a χ2 test for
categorical data. A two-sided p value less than o.o5 was considered
significant.
This study was approved by the Institutional Committee on Human Research
of our institution.
RESULTS
The HT and the No HT groups included 93 patients each. The mean age was
66 ±12 years and the majority of patients in both groups were men
(65%). There were no differences in the percentage of patients with
comorbidities and in other baseline clinical characteristics of both
groups except for a higher rate of previous PCI in the No HT group (47%
vs. 26%, p<0.05). The great majority of patients in both
groups presented with acute coronary syndromes (90%) with a high
prevalence of NSTEMI or evolved STEMI patients (64%). No differences
were observed in the complexity
of the coronary artery disease according either to the number of vessels
with significant stenosis or the SYNTAX Score.
Significant three vessel disease
or left main disease was seen in 75% of the HT group and 80% of the No
HT group (p=0.49). Baseline characteristics are presented in Table 1.
The mean SYNTAX score was similar between groups (19±6 in the No HT and
21±6 in the HT group, p=0.589) although there was a trend for a greater
percentage of patients with low SYNTAX scores in the No HT group (75.3%
in the No HT and 59.6% in the HT group p=0.06). The mean perioperative
risk according to the STS score was low and similar in both groups (3±2
vs. 3±3). Again, there was a trend for a higher percentage of patients
with intermediate and high STS scores in the No HT group, compared to
the HT group (22% vs 8% and 12% vs 8% respectively, p=0.052). (Table
2)
A significant difference in the
modality of treatment chosen in each period was observed. In cases
treated without HT discussion, PCI was the most frequent method of
treatment, being employed in 69% of cases. During the HT period we
observed a radical change in treatment recommendations, with most
patients being referred to CABG (63%) (Figure 1). This corresponds to a
174% increase in the use of surgical revascularization.
On the other hand, there was a significant increase in the time from
diagnostic angiography to revascularization in the HT group (8.5 ±4
days) in comparison with the No HT group (1.8 ± 5 days). (Table 3). When
examining this variable according to revascularization strategy, time to
CABG was similar in both the HT and No HT groups (7±8 vs 8±5, p=0.75)
but the time to PCI was substantially longer in the HT group compared to
the No HT group (0.39±2 vs 8±6 p<0.01).
DISCUSSION
This study shows that the implementation of Heart Team discussion in the
decision-making process of patients with complex coronary artery disease
was associated with a profound change in the strategy for
revascularization characterized by an increased rate of CABG with a
reduction in the rate of PCI. Moreover, HT discussion was associated
with a significant delay in the time to PCI in comparison with patients
treated in earlier periods before the establishment of the HT.
The Heart Team has been recommended as standard care for patients with
complex CAD since the publication of the European and American
guidelines for myocardial revascularization in 2010 [6, 10]. This
recommendation, while intended to provide interdisciplinary sharing of
knowledge and experience in decision-making, is based solely on expert
opinion. As such, little is known about the impact of this approach on
rates of revascularization methods and on short and long-term outcomes
as well as immediate peri-procedural risks and potential benefits in
each individualized setting.
The main finding of our study was a significant change in the
revascularization modalities before and after HT implementation. In
fact, there was an increase in CABG recommendations from 23% without HT
to 63% in the HT group with a parallel decrease in the rate of PCI.
There are a few possible explanations for this substantial change:
first, the baseline characteristics of the patients was slightly
different. Despite individual matching, a trend for a lower STS score
was observed in the patients in the No HT group. This difference however
should have favored a surgical approach within this group, and these
were not the results that were noted.
In addition, the mean SYNTAX score and the proportion of patients with
intermediate or high SYNTAX scores was numerically higher in patients
discussed by the HT, although not statistically significant. This may
reflect the fact that the patients in the HT group had more complex
coronary anatomy hence being referred to surgery more often. In fact,
the past two decades have seen a myriad of trials [2, 11-16] seeking
to answer the question of which strategy provides better short and long
term outcomes for complex CAD while balancing patient satisfaction and
costs, mainly in the setting of stable disease. In summary, most trials
on multivessel disease show a survival advantage of CABG over PCI
according to anatomical complexity as assessed by the SYNTAX score,
while there are no clear benefits to either treatment when it comes to
isolated LM disease. Based on these findings, an intermediate or high
SYNTAX score is recognized by recent revascularization guidelines as a
class IA indication for CABG over PCI [4, 17]. Furthermore, the
FREEDOM randomized trial [18] compared CABG to PCI solely in
diabetic patients with multivessel disease and found reduced mortality
associated with the surgical approach. The accumulation of data on the
subject as well as updated guideline recommendations might have
influenced the change in revascularization strategies seen in our study
in the last few years. Supporting this observation is the fact that the
operator in the HT period between 2016 and 2017 recommended CABG in 57%
of the cases whereas only 23% of operators during the No HT period
(2005-2015) referred the patients for surgery.
Other factors such as personal tendencies and beliefs of the
cardiologists involved as well as financial or professional interests
that could influence the revascularization decision are neutralized by
the HT discussion leading to a change in treatment strategies. This
point was emphasized in a study by Abdulrahman et al [19]
that described how HT recommendations changed according to which
professionals were present at the discussion.
Our findings are similar to recent reports in the literature. In 2016,
Bonzel et al . [20] described that between 46-66% of patients
discussed by the HT were referred to isolated CABG. They also
demonstrated that the patients referred to PCI had a low rate of need
for CABG during long term follow up with no increase in mortality after
2 years. Also, a possible intrinsic bias of the interventional
cardiologist in recommending PCI as a primary revascularization approach
was noticed in a study by Sanchez et al [21] that used the HT
to review decisions on revascularization strategies based on SYNTAX and
STS scores and on Appropriate Use Criteria for coronary
revascularization. They found that 34.9% out of 301 patients who had
undergone PCI in the past two years had an inappropriate or uncertain
indication for angioplasty as recommended by the HT.
Another important finding of the present study is that the decision to
bring the case to HT discussion was associated with a significant delay
in the performance of revascularization. Indeed, we observed a
significant increase in ”time to PCI” from an average of 0.36 days to 8
days, while the time to CABG did not differ substantially. This was most
probably due to a limitation in institutional resources, but could also
occur in other hospitals should the HT approach be systematically
adopted. Taking into account that the population analyzed included 90%
of patients with ACS, such a delay may be associated with potential
risks for this population. According to the European Society of
Cardiology/European Association for Cardio-Thoracic Surgery (ESC/EACTS)
guidelines on myocardial revascularization [6], PCI or CABG should
be performed within 6 weeks after angiography for patients presenting
stable coronary disease and within 2 weeks for patients with a high-risk
coronary anatomy. For patients presenting with ACS the recommended time
frame for revascularization is shorter, based on adverse events that may
occur while on the waiting list for revascularization. Guidelines for
the management of patients with non-ST elevation acute coronary
syndromes (NSTE-ACS) [22] recommend an invasive strategy in moderate
to high-risk patients. The timing of the intervention in those patients
is dependent on the patient’s baseline risk factors and extend up to 72
hours from initial presentation. The HT approach potentially promotes
delays in time to revascularization which was evident in the population
that was ultimately treated by PCI, in conflict with the aforementioned
recommendations. Multiple trials investigated and confirmed the value of
early revascularization in patients with NSTEMI (8), although the
clinical significance and major events rate during the waiting period
until revascularization after the HT have not been investigated. The
present study was not designed to examine such clinical outcomes, which
would be valuable data to be reported in follow up research.
Nevertheless, a 2018 single center [9] study of 1000 consecutive
patients concluded that the HT approach was feasible, with decision
making and treatment following within a short time after referral and
largely in accordance with clinical guidelines. This study however,
included mainly patients referred from a community setting and as such
the mean time to revascularization of 6 weeks was considered safe and
appropriate.
Our study has a number of limitations. First, this was an observational
study with a retrospective attempt of matching patients on the basis of
clinical and angiographic variables. Despite this attempt, numerical
differences in the number of patients with previous PCI, the complexity
of CAD and surgical risk were observed between groups. This potential
selection bias could explain differences in the choice of type of
revascularization between the two periods. Secondly, our sample size
might have been small to detect differences in characteristics between
the groups. Third, there was no long-term outcome follow up of the
patients treated with and without HT discussion. Further research into
the impact of HT discussions on clinical outcomes would be most
certainly welcome.
Nonetheless, this is to the best of our knowledge the first study to
analyze the change in revascularization policy associated with the
introduction of systematic, institutional HT discussions for complex
CAD.