Determinants of Percutaneous Coronary Intervention and Coronary Artery Bypass Grafting: A Systematic Review and Meta-analysis
Correspondence Address :
Dr. Premjithlal Bhaskaran,
Department of Cardiothoracic Surgery, Imperial College, London, United Kingdom.
Introduction: Coronary Artery Bypass Graft (CABG) surgery has potential benefits for patients with Coronary Artery Disease (CAD). The consensus associated with Percutaneous Coronary Intervention (PCI) and CABG was in terms of clinical outcomes, type of vessel disease, repeat revascularization, stroke, myocardial infarction, and heart failure. Hence, a comparison of PCI versus CABG is becoming important to identify patients who would benefit from PCI and CABG.
Aim: This review was conducted to identify the pathophysiological determinants of PCI and CABG.
Materials and Methods: In the present systematic review, Medline (PubMed), EMBASE, ProQuest, and the Cochrane database were searched, by using the key words “PCI” OR “percutaneous coronary intervention” AND “CABG” OR “coronary artery bypass grafting”. The searches were restricted from January 2009 to June 2021, with studies published in the English language. Comparative studies of CABG versus PCI with stent placement were the inclusion criteria. For meta-analysis Mantel–Haenszel Odds Ratio (MHOR) with its 95% Confidence Interval (CI), Mean Difference (MD) with its 95 % CI were computed.
Results: Overall, 408 titles or abstracts were identified from the initial search, of which full manuscripts of 93 studies were retrieved, in the first phase. Later, 71 studies were excluded. Of the remaining 22 studies, 19 were subjected to meta-analysis. This review contributes a sample size of 17,053. Mean age of the study population of PCI group was 66.15±10.71 years and in CABG group it was 66.16±9.43 years. PCI was performed among patients with higher ejection fraction (MD=2.13; 95% CI=1.75 to 2.52) or higher Synergy between percutaneous coronary intervention with Taxus and coronary artery bypass surgery (SYNTAX) score score (MD=-3.43; 95% CI=-3.98 to -2.87). CABG was considered for the patients with a higher Euro score (MD=0.28; 95% CI=0.2 to 0.35).
Conclusion: The ejection fraction, SYNTAX score, euro score, type of vessel disease, chronic kidney disease, and diabetes are the determinants of PCI and CABG.
Coronary artery disease, Ejection fraction, Euro score, Revascularisation
Percutaneous coronary intervention is focused on treating flow disrupting lesions and it is constrained to new infarcts. The CABG supports the flow distal to the occluded vessel. The CABG was primarily done in patients with triple vessel disease and PCI was performed in single or double vessel diseased cases (1).
Even though PCI is routinely followed, the CABG is considered as gold standard for cardiac remodeling. The consensus associated with PCI and CABG was in terms of safety outcomes, especially an increase in repeat revascularization in PCI and an increase in the incidents of strokes among CABG cases. However, CABG is the best revascularization technique, conferring decreased mortality and risk of repeat revascularization (2). PCI is suggested to be an appropriate revascularization procedure in patients with a lower SYNTAX score and CABG is preferred for the cases with a high euro score (3). Non-surgical patients present a challenge in the treatment and are recommended for the PCI with bare metal stents. Unfortunately, the mortality and revascularization rates are inferior among PCI cases, when compare with CABG (4).
CABG is not a cure for Coronary Heart Disease (CHD), as it does not stop disease progression and the grafts can calcify with restenosis. It also carries the risks of Myocardial Infarctions (MI), stroke, arrhythmias and death. PCI has advanced the survival of patients with CHD by reducing the need for CABG. Independent of stent type used, the PCI reports patient survival as well as the incidence of MI (2). Despite the development in stent technology, pharmacotherapy or adjunctive imaging, which made the use of PCI a common treatment regimen, CABG continues to be the standard treatment for CAD. However, the optimal revascularization procedure in CAD patient’s remains controversial (5). The emergence of drug eluting stents and advancement in technology has caused a pivotal role in cardiology (6). Hence, identifications of patients who would benefit from PCI and CABG would be intriguing. This review aimed to identify the pathophysiological determinants of PCI and CABG.
In the present systematic review, Medline (PubMed), EMBASE, ProQuest, and the Cochrane database were searched, by utilizing a combination of the relevant Medical Subject Heading (MeSH) terms and the key words “PCI” OR “percutaneous coronary intervention” AND “CABG” OR “coronary artery bypass grafting”. In the Cochrane database the search was limited by the term “clinical trial”. The searches were restricted from January 2009 to June 2021 with studies published in the English language. Citations were screened at the title or abstract level and retrieved as a full report if they were clinical studies, compared PCI with CABG.The literature search and analysis was conducted from December 2020 to June 2021.
Inclusion criteria: Randomized Controlled Trials (RCTs), cohort and descriptive studies, which made an attempt to address the pathophysiological characteristics of revascularization procedures, were included. The studies conducted on adult patients who underwent PCI or CABG irrespective of study setting and regions were also included.
Exclusion criteria: If the outcome measure (pathophysiological determinants) was not reported or was impossible to extract or calculate from the available results, then such studies were excluded.
Search strategy: Screening criteria in preliminary search were the pathophysiological determinants associated with PCI and CABG. In the second phase full manuscripts of all the studies which qualified the screening criteria, were obtained. Selection criteria were applied to each of these studies and valid studies were subjected for final data extraction.
Methods used to collect the data: The keywords “PCI” OR “percutaneous coronary intervention” AND “CABG” OR “coronary artery bypass grafting” were entered into different database and year wise search was conducted. Titles or abstracts were screened for the content and full manuscripts of the studies were obtained. All the downloaded articles were studied and subjected for eligibility criteria and a list of selected studies was obtained. They were further subjected for inclusion and relevant data were extracted.
Quality assessment: All the included studies for meta-analysis were subjected to methodological quality appraisal using the Cochrane risk of bias assessment tool, and the Joanna Briggs Institute (JBI) checklist for descriptive and cohort studies (7), (8). For each item the response was recorded as yes or no and a credit point of “one” was assigned for yes and “zero” for no. Total counts of all the points were obtained. Higher counts indicates well appraisal.
For meta-analysis MHOR, MD, and 95% CI were computed by using the fixed effect model. The Chi- square and I2 statistic were used to test heterogeneity (9).The Review Manager Software (Rev Man 5, Cochrane collaboration, Oxford, England) was used for data analytics (10).
Overall, 408 citations were identified from the initial search, of which 93 studies were retrieved. Later, 315 studies were excluded. Of the remaining 22 studies, 19 were subjected to meta-analysis in the second phase (Table/Fig 1). The critical appraisal of the studies included in the present review has been shown in (Table/Fig 2) (11),(12),(13),(14),(15),(16),(17),(18),(19),(20),(21),(22),(23),(24),(25),(26),(27),(28),(29),(30),(31),(32).
The studies selected for meta-analysis (n=19) contributed a sample of size 17,053 (Table/Fig 1). A total of 9,663 (57%) patients underwent PCI and 7,390 (43%) underwent CABG. Mean age of the study population in PCI group was 66.15±10.71 and in CABG group it was 66.16±9.43.Thus age was homogeneous (MD=0.14; 95% CI=-0.15 to 0.43) between PCI and CABG (Table/Fig 3).
The majority of the study population was males (71% in the PCI group and 73% in CABG). Performance of PCI or CABG was not associated (MHOR=0.97; 95% CI=0.91 to 1.04) with gender (Table/Fig 4).
The PCI was extensively performed in single vessel disease cases (MHOR=3.09; 95% CI=2.6 to 3.68) or double vessel disease cases (MHOR=2.52; 95% CI=2.25 to 2.81) (Table/Fig 5),(Table/Fig 6). The patients with triple vessel disease underwent CABG (MHOR=0.24; 95% CI=0.21 to 0.26) (Table/Fig 7).
Choices for PCI and CABG was not associated with peripheral vascular diseases (MHOR=0.99; 95% CI=0.82 to 1.19), cardiovascular diseases (MHOR=0.92; 95% CI=0.56 to 1.52), previous MI (MHOR=1.1; 95% CI=1 to 1.21), previous heart failure (MHOR=0.91; 95% CI=0.78 to 1.05), Hyperlipidemia (MHOR=1; 95% CI=0.88 to 1.14) smoking habit (MHOR=0.89; 95% CI=0.83 to 0.95), hypertension (MHOR=0.93; 95% CI=0.87 to 1) and stroke (MHOR=1.04;95% CI=0.91 to 1.19) (Table/Fig 8),(Table/Fig 9),(Table/Fig 10),(Table/Fig 11),(Table/Fig 12),(Table/Fig 13),(Table/Fig 14),(Table/Fig 15).
The PCI and CABG improve prognosis in CAD patients by attenuating the ischemic state and reversing the left ventricular remodeling (33). Effectiveness of PCI and CABG is associated with revascularization and clinical outcomes. Cases with an EF of 35% or less have reported better survival with CABG than PCI (34).Those patients who undergo PCI multiple times before being referred for CABG were at higher risk for graft failure (33).
CABG has been found to be superior to PCI in patients older than seventy years with respect to the incidence of adverse cardiac events. Among the patients younger than seventy years, there was no difference in the adverse cardiac events between PCI and CABG (35). In this study, there was no difference in age between PCI and CABG groups. Also, the performance of PCI and CABG was not associated with gender. However, despite the similar prevalence of CAD between the genders, female cases were less likely to undergo revascularization (36).
PCI is associated with single or double vessel diseases and it is mainly driven by higher rates of myocardial infarction and revascularization. CABG is associated with multi-vessel or unprotected left main coronary artery disease (15). The lower rate of adverse cardiac or cerebrovascular events at one year among patients with triple vessel diseases or left main CAD (or both) induces CABG as standard care as compared with PCI (37). CABG improves Left Ventricular (LV) function and it reverses adverse remodeling. This has resulted in improved survival rate and decreased the incidence of adverse cardiac events. However, CABG in patients without viable myocardium (hibernating / stunned myocardium)leads to an unfavorable structural alteration and the clinical benefits (38). The magnitude of the recovered ventricular function was reported to be proportional to the amount of dysfunctional myocardium, greater than 25% LV (four from seventeen segment model) results in improvement in reverse remodeling (38). The rate of peripheral vascular diseases, previous MI, heart failure, stroke, diabetes, hyperlipidemia, smoking habit and hypertension are consistently homogeneous between PCI and CABG.
Patients with previous CABG often develop progression of atherosclerotic diseases and hence they may require further revascularization. Among such cases, PCI is associated with higher incidence of restenosis, procedural complications and chronic adverse cardiac events (32). However, PCI with drug eluting stents for ostial or mid-shaft lesions in CAD demonstrated favorable clinical outcomes than PCI for distal bifurcation lesions (31). The ability of drug eluting stents to reduce restenosis as compared to PCI with bare metal stents enhances their use in CAD. Thus, in left main stenosis has become an alternative to surgery and it favors for further revascularization (30).
Patients with a high SYNTAX score undergo CABG and cases with a high euro score followed PCI. Performance of PCI is also associated with a higher ejection fraction (3). PCI with stent implantation and CABG are associated with Q-wave MI, cerebrovascular accidents, angina, or stroke among CAD patients (12),(15). The Target Vessel Revascularization (TVR) rates were reportedly higher among PCI group than CABG. This inferiority character of TVR was associated with repeat revascularization, whereas the risk of MI was non inferior in PCI cases with lower perioperative morbidity (31). In PCI group, the rate of long-term repeat revascularization was higher than CABG. The decision towards PCI and CABG also determined by the anticipated periprocedural risk, graft occlusion and restenosis; based on the SYNTAX score, lesions observed in morphology, and underlying co-morbidities (23), (27)
Stratification of patients into PCI and CABG was reported among the included studies have been followed by the eligibility criteria of this review. However, the PCI procedures can be altered with respect to number of stents implanted, repeated revascularization, and types of techniques (culotte / V-stenting / protrusion / crush) used. These heterogeneities were the major limitations of this study.
The PCI is thought to be limited mainly to single vessel disease whereas CABG provided better outcomes in complex multi vessel diseased cases. The ejection fraction, SYNTAX score, euro score, type of vessel disease, CKD, and presence of diabetes are the pathophysiological determinants for PCI and CABG.
Date of Submission: Jul 03, 2021
Date of Peer Review: Oct 05, 2021
Date of Acceptance: Dec 11, 2021
Date of Publishing: May 01, 2022
• Financial or Other Competing Interests: None
• Was Ethics Committee Approval obtained for this study? No
• Was informed consent obtained from the subjects involved in the study? NA
• For any images presented appropriate consent has been obtained from the subjects. NA
PLAGIARISM CHECKING METHODS:
• Plagiarism X-checker: Jul 05, 2021
• Manual Googling: Nov 19, 2021
• iThenticate Software: Dec 08, 2021 (11%)
ETYMOLOGY: Author Origin
- Emerging Sources Citation Index (Web of Science, thomsonreuters)
- Index Copernicus ICV 2017: 134.54
- Academic Search Complete Database
- Directory of Open Access Journals (DOAJ)
- Google Scholar
- HINARI Access to Research in Health Programme
- Indian Science Abstracts (ISA)
- Journal seek Database
- Popline (reproductive health literature)