Clinical Review of Coronary Revascularization in Special Subgroups in the Current Era-Juniper Publishers
JUNIPER PUBLISHERS-OPEN ACCESS JOURNAL OF CARDIOLOGY &
CARDIOVASCULAR THERAPY
Coronary artery bypass grafting (CABG) and
Percutaneous coronary intervention (PCI) revascularization strategies
have undergone significant advancements in recent years, creating the
need to reexamine data from clinical studies and critically scrutinize
existing guidelines in order to determine the optimal care for each
individual patient. In this review, we aim to address the current data
available for the treatment of patients with multi vessel disease,
focusing on special population subgroups based on advanced age, gender,
previous CABG, renal failure and diabetes mellitus. This synthesis of
information is necessary and timely as it will provide an essential
framework for physician dialogue and evidence-based approach of coronary
revascularization in the current and beyond in the management of these
selected patients.
Abbreviations:PCI: Percutaneous Coronary Intervention; DES: Drug-Eluding Stent; MVD: Multi-Vessel Coronary Artery Disease; CABG: Coronary Artery Bypass Grafting; ARTS I: Arterial Revascularization Therapies Study Part I; MASS II: Multi vessel Coronary Artery Disease; ERACI-II: Patients with Multiple Vessel Disease; SOS: Stent on Surgery; ASCERT: American College of Cardiology Foundation and the Society of Thoracic Surgeons Collaboration on the Comparative Effectiveness of Revascularization Strategies; DM: Diabetes Mellitus; HCR: Hybrid Coronary Revascularization
Introduction
Multivessel coronary artery disease (MVD) is defined
by significant atherosclerosis (>70% occlusion) involving at least
two or three of the major coronary arteries, and it occurs in 40-65% of
patients with acute myocardial infarction [1]. MVD is associated with a
higher burden of comorbidities and left ventricular dysfunction, and it
significantly increases the risk of morbidity and mortality after
interventional therapy, as observed in previous studies [1,2]. Numerous
additional studies on MVD have contrasted coronary artery bypass
grafting (CABG) with the various methods of Percutaneous coronary
intervention (PCI), from balloon angioplasty and bare metal stents, to
first- and second-generation drug- eluting stents, and conclusions have
fluctuated with time. Several factors contribute to this discrepancy,
including but not limiting to the size and nature of the patient
population, the type of technology utilized as well as experiences of
the clinicians performing those procedures. To incorporate multiple
trials and draw empirical conclusions with enough statistical power and
confidence, it is beneficial to conduct a meta-analysis of randomized
controlled trials or refer to large clinical registries or other
observational datasets.
Clinical trials investigating bare metal stent PCI
versus CABG in multi vessel CAD include the Arterial Revascularization
Therapies Study Part I [ARTS I], the Medicine, Angioplasty, or Surgery
Study for Multi vessel Coronary Artery Disease [MASS II], the Argentine
Randomized Study of Coronary Angioplasty with Stenting versus Coronary
Bypass Surgery in Patients with Multiple Vessel Disease [ERACI-II]. In
these studies, negligible difference was noted in long-term survival
rates [3,4]. Secondary outcomes from these trials revealed an increased
need for revascularization after 5 years with bare metal stenting [3,4].
However, when comparing first generation drug- eluting stents to CABG
in the Stent on Surgery (SOS) trial, Booth and colleagues showed a
continuing survival advantage after 6 years for patients who had a CABG
[5]. Notably, PCI consistently reduced hospital mortality in all age
groups [6].
CABG patients experienced greater relief from angina than
those undergoing PCI, though the difference was minimal [7].
The ASCERT (American College of Cardiology Foundation and the
Society of Thoracic Surgeons Collaboration on the Comparative
Effectiveness of Revascularization Strategies) published in the
New England Journal of Medicine showed that even though
CABG had better outcomes over a period of four years (16.4%
versus 20.8%; risk ratio 0.779), it did so with a higher financial
burden than PCI [8]. More recently, in 2015, an observational
registry study in New York compared second-generation DES
to CABG (n=9223 matched pairs). PCI with evorlimus-eluting
stents had a lower risk of death and stroke within 30 days of
the procedure, though there was no difference long-term (>30
days) [9].However, PCI was found to be associated with greater
risk of myocardial infarction in patients with incomplete
revascularization, and a need for future revascularization.
Likewise, authors of this study propose weighing the shortterm
risk of death and stroke with CABG against the long-term
need for additional revascularization and the risk of myocardial
infarction if complete revascularization cannot be achieved.
Importantly, specific patient subgroups with multi vessel
coronary disease must be evaluated and assessed critically in
order to determine the most optimal treatment strategy i.e.
CABG or PCI. These subgroups include patients with advanced
age, gender, previous CABG, renal failure and diabetes mellitus.
Choice of coronary revascularization strategy in special subgroups
a) Patients aged 65 and older:The elderly patient
population requires special attention, because of increased
risk of mortality and perioperative complications with
revascularization in the setting of multiple comorbidities and
overall frailty. Weintraub et al. [10] investigated elderly patients
and determined that after 4 years there was lower mortality as
well as a long term survival advantage with CABG than with PCI
in patients65 years and older with two- or three-vessel coronary
artery disease without acute myocardial infarction. A 2009
meta-analysis of 10 clinical trials also reported lower mortality
rated with CABG intervention than PCI for those greater than
65 years [11]. In a population of octogenarians, Singh et al also
determined that the mortality rate was five times higher in
comparison to the younger population and actually represents
thirty percent of all deaths after PCI [6].In fact, in a cohort of
previous studies, age was actually an independent predictor of
outcomes after Percutaneous revascularization overall [6].
b) Gender:While the majority of patients with coronary
artery disease are men, CAD is also the leading cause of death in
women [6,12,13], yet women receive less revascularization and
evidence-based medications [14]. In a population-based cohort
study that spanned a decade, Guru et al. showed that women
have a more complex clinical preoperative presentation and
unfortunately are more likely to be readmitted with unstable angina and congestive heart failure after CABG, despite having
similar survival to men [12]. In some studies, such as the one
by Lempereur et al. [15] that examined the risk factors for
in- hospital mortality following PCI, female sex remained an
independent predictor of mortality. Furthermore, in evaluating
DES versus BMS angioplasty, while there is a profound prognostic
advantage for both genders, female patients reportedly had a
higher benefit [16].
c) Previous CABG:angina and congestive heart failure after CABG, despite having
similar survival to men [12]. In some studies, such as the one
by Lempereur et al. [15] that examined the risk factors for
in- hospital mortality following PCI, female sex remained an
independent predictor of mortality. Furthermore, in evaluating
DES versus BMS angioplasty, while there is a profound prognostic
advantage for both genders, female patients reportedly had a
higher benefit [16].
d) Renal Failure:Kidney function is an important
clinical parameter to assess when considering coronary
revascularization. Chronic renal disease and renal failure are
common sequale of CAD and increase patients’ risk of procedurerelated
morbidity and mortality [18,19]. Additionally, patients
with end stage renal disease have a much greater incidence of
CAD and acute myocardial infarction [20,21]. Hemmelgarn et al.
[22] evaluated survival in patients who received CABG, PCI or
no revascularization for three stratifications of kidney function:
dialysis-dependent kidney disease, non-dialysis- dependent
kidney disease, and a group with serum creatinine above 2.3
mg/dL (reference group).
Based on their data, CABG was associated with increased
survival in all groups of kidney disease, while PCI was superior
to the no-revascularization group particularly in the reference
group patients and the dialysis- dependent group [22]. This
study was further validated by Krishnaswami et al. [23] in which
CABG is more favorable than PCI with stenting, primarily due to a
low re-operation rate, despite a higher level of invasiveness and
longer recovery time. Despite these results, however, a recent
assessment of nationwide trends in revascularization for patients
with end stage renal disease showed that PCI intervention for a
ST-elevation myocardial infarction has increased from 18.6% to
37.8% between 2003 and 2011; CABG had decreased slightly,
6.1% to 5.7% [24].>/p>
There was no significant difference seen at 1-year, and
no difference in incidence of non-fatal myocardial infarction
between the two groups. However, the relative risk of stroke
after CABG was 2.4 times that of PCI patients (PCI risk of 0.8%).
While CABG currently appears to be a superior technique to PCI
in the diabetic subgroup, the impact of covariates on this decision
remains uncertain. Comparing patients with insulin-treated
diabetes mellitus with non- insulin treated patients, a subgroup
analysis of the FREEDOM trial study found minimal difference
in PCI versus CABG [27]. Thus, factors of insulin use, gender,
age, and comorbidities should be taken into consideration for
treatment of CAD in patients with diabetes.
Treatment patterns of coronary artery disease either
through PCI or CABG have evolved significantly over the last
decade, especially with the advent of moresophisticated stent
technology such bio-absorbable vascular scaffolds, novel anti
platelet agents, robust imaging and surgical platforms, as well
as reliable extracorporeal circulatory support devices. Likewise,
in recent years, institutional experiences have also grown
resulting in better outcomes and improved efficacies of both
these procedures. At the same time, there is also widespread
interest among clinicians to minimize surgical trauma and
improve techniques to further improve graft patency following
CABG procedures. This has been achieved via standardization
of routine surgical procedures, and use of buffered saline
graft preservation solutions [28]. The field of hybrid coronary
revascularization (HCR)- involving simultaneous or staged PCI/
CABG procedures in select patients- has also emerged in recent
years with comparable and promising outcomes to CABG alone
[29]. In a recent survey among 200 cardiologists and cardiac
surgeons from 100 top-ranked U.S. hospitals, more than 75% of
responders felt that HCR is a reasonable alternative technique for
coronary revascularization among suitable patients (including
older and relatively healthy patient population without complex
lesions)
Most predicted that the use of HCR would increase in
the next decade [30]. While the current state of HCR is still
limited to selected patients, with increasing engagement
from and dialogue between the interventionists and surgical
communities, as well as validated data from RCTs, HCR has the
possibility of being a reliable revascularization strategy in the
upcoming years. This review is by no means comprehensive,
but rather serves as a framework in initiate physician dialogue
on the optimal management of select, and in some ways at-risk
patient subgroups. It also serves to synthesize existing literature
with a goal of pointing out various knowledge gaps that could
potentially be addressed through additional research studies.
For more articles in Open Access Journal of Cardiology & Cardiovascular
Therapy please
click on:
https://juniperpublishers.com/jocct/index.php
https://juniperpublishers.com/jocct/index.php
Comments
Post a Comment