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 Table of Contents  
ORIGINAL ARTICLE
Year : 2022  |  Volume : 10  |  Issue : 3  |  Page : 128-133

Coronary endarterectomy – A way to complete revascularization


1 Department of Cardio Vascular and Thoracic Surgery, U. N. Mehta Institute of Cardiology and Research Centre, Ahmedabad, Gujarat, India
2 Department of Research, U. N. Mehta Institute of Cardiology and Research Centre, Ahmedabad, Gujarat, India

Date of Submission02-Sep-2022
Date of Decision15-Oct-2022
Date of Acceptance27-Oct-2022
Date of Web Publication14-Dec-2022

Correspondence Address:
Jignesh Kothari
Department of Cardio Vascular and Thoracic Surgery, U. N. Mehta Institute of Cardiology and Research Center, Ahmadabad, Gujarat
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/heartindia.heartindia_39_22

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  Abstract 


Background and Aim of the Study: Coronary endarterectomy (CE) is performed adjacent to coronary artery bypass grafting (CABG) grafting to aid complete revascularization. However, the purpose of CE in surgical management of diffuse coronary artery disease (CAD) is controversial. The objective of this study was to highlight the operative outcomes, safety, and complications associated with CE.
Methods: An observational, prospective research was carried out in the Department of Cardiovascular and Thoracic Surgery at our institute. All patients undergoing isolated CABG + CE from 2019 till 2021 were evaluated. Patients undergoing urgent, emergency, or elective CABG + CE off-pump/on-pump surgery were enrolled.
Results: One hundred patients with CABG + CE were evaluated based on symptomatology with sequential electrocardiogram monitoring and blood samples for cardiac biomarkers. The blood samples were taken 6, 12, 24, 48, and 72 h following surgery. Eighty-five patients required single CE and 15 patients required double CE. We noticed a rising trend of cardiac markers in the first 6 h, reaching its peak level at 24 h, and downward trend following 72 h following surgery. Although patients had a tremendous rise in the cardiac biomarker values, clinically patients were stable with operative mortality of 5%.
Conclusions: We believe CE helps in complete revascularization in patients with diffuse CAD. CE should be given due consideration in an era where it has been neglected due to its complexities and accompanying myths. CE is an important and integral weapon in a surgeon's armamentarium, and we should not hesitate to perform CE due to associated myths.

Keywords: Coronary artery bypass grafting, coronary artery disease, coronary endarterectomy


How to cite this article:
Patel H, Gohil I, Kothari J, Shah P. Coronary endarterectomy – A way to complete revascularization. Heart India 2022;10:128-33

How to cite this URL:
Patel H, Gohil I, Kothari J, Shah P. Coronary endarterectomy – A way to complete revascularization. Heart India [serial online] 2022 [cited 2023 Feb 2];10:128-33. Available from: https://www.heartindia.net/text.asp?2022/10/3/128/363541




  Introduction Top


Heart disease is on the rise globally, and the Indian population is no exception. However, one remarkable fact is that it is progressing more quickly in young Indians than in their global counterparts.[1] The incidence of coronary artery disease (CAD) in young Indians has been rising in urban population, and it was estimated to be 12%–16% by 2020.[2] The peculiar feather of CAD among the Indian population is that it is diffuse in nature and it is premature.[1]

Different strategies exist for diffuse CAD ranging from purely medical management to percutaneous coronary intervention (PCI) to surgical coronary revascularization or transmyocardial laser revascularization. However, each of these methods for diffuse CAD is not completely characterized. Research shows that up to 12% of patients undergoing coronary angiography are not suitable for surgical or percutaneous intervention.[3]

In the context of the aforementioned issues and an effort to improve the success rate of coronary artery bypass grafting (CABG), the relevance of coronary endarterectomy (CE) has been reviewed. CE is a procedure in which coronary artery is opened longitudinally and atheromatous plaque occluding the vessel is extracted.[4] The study aims to enlighten the wider perspective of this complex procedure. This study also evaluates the overall outcomes including postoperative complication in postoff-pump coronary endarterectomy done at our institute.

Study design

An observational, prospective study was carried out in our institute after obtaining ethical approval from the committee “UNMICRC (UNMICRC/CVTS/2018/22)”. From 2019 to 2021, patients undergoing off-pump/on-pump CABG with concomitant CE were studied. The decision for CE was purely based on the preoperative angiograms and intraoperative vessel anatomy.

Inclusion criteria

All patients receiving off-pump/on-pump CABG + CE, including urgent, emergency, and elective surgery, were included in the study.

Exclusion criteria

Bypass surgery with concomitant valvular heart surgery or redo surgery were excluded.


  Methods Top


Data regarding demographics, comorbid conditions, and intraoperative and postoperative parameters were noted. society of thoracic surgeons (STS) definitions were used to define variables including postoperative outcomes and causes of mortality.[5]

In postoperative period, blood samples were collected to estimate myocardial enzymes (CK-MB and cTnI) immediately after shifting into the intensive care unit (ICU) and at 6, 12, 24, 48, and 72 h following surgery. The standard 12-lead electrocardiogram (ECG) was taken on shifting the patient to ICU and repeated every day till the 5th day of the surgery. All ECGs were analyzed by the same observer and compared with the preoperative recording. All patients received injection heparin 5000 IU and tablet aspirin 150 mg and clopidogrel 75 mg from the day of surgery. Tablet warfarin was added for the next 3 months. Inhospital mortality and morbidity were recorded.

Definitions

Emergency CABG was defined as unscheduled surgery required in the next available theater on the same day due to refractory angina or cardiac compromise.

Urgent CABG was defined as a procedure required during the same hospitalization in order to minimize the chance of further clinical deterioration. This includes worsening sudden chest pain, congestive heart failure(CHF), an acute myocardial infarction (MI), threatening coronary anatomy, intra-aortic balloon pump (IABP), unstable angina, or rest angina.

Low cardiac output syndrome (LCOS) was defined as the decrease in the cardiac index to <2.0 L/min/m2 and the systolic blood pressure of <90 mmHg, with elevated end-diastolic pressure on the right (>10–15 mmHg) and/or pulmonary capillary wedge pressure (PCWP) (>18 mmHg) in the left side of heart, in the conjunction with sign of tissue hypoperfusion (cold periphery, clammy skin, confusion, and elevated lactate level), oliguria (urine output <0.5 ml/kg/h.) in the absence of hypovolemia, and need of inotropic supports or mechanical circulatory supports to improve patient hemodynamics

Operative technique

CE was done when the target vessel was found to be substantially calcified, making bypass grafting unsafe and insecure. All CE operations were carried out without the cardiopulmonary bypass (CPB). The saphenous vein (SV) and the internal thoracic artery (ITA) were used for grafting.

The closed method was used for CE.[6] Two fine forceps were used to apply gentle traction to extract atheromatous core from adventitia. We took care not to disrupt endarterectomy core and pulled it out completely with tapering end distally [Figure 1]. In cases a core was still in place, the length of incision was extended distally and extraction was achieved. Following the endarterectomy, bypass was accomplished with ITA or SV graft.
Figure 1: Coronary endarterectomy

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Endarterectomy of the left anterior descending (LAD) artery required an open technique to remove the plaques from individual septal branches. Manipulation on the proximal plaque was restricted to prevent competitive flow from native artery. Following CE, ITA was grafted in all LAD using onlay technique.[6]

Statistical analysis

Statistical analysis was done using software SPSS v. 20. Continuous variables were expressed as mean ± SD, whereas categorical variables were defined as percentage.


  Results Top


Total 100 patients underwent CABG + CE from 2019 to 2021. The preoperative data are presented in [Table 1]. All patients intended for off-pump CABG + CE. In four patients, the procedure had to be converted to on-pump surgery. There was one intraoperative death. Eighty-five patients required single EA and 15 patients required double EA. Left ITA and SV graft were used as conduits in all patients. [Table 2] and [Table 3] highlight the number of EAs in each case with total number of grafts and postoperative parameters, respectively.
Table 1: Characteristics of patients who underwent coronary artery bypass graft + coronary endarterectomy

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Table 2: Number of endarterectomies

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Table 3: Postoperative complication following coronary endarterectomy

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The mean ventilation time (h) and ICU stay were 9 h and 70 h, respectively. Nineteen patients were diagnosed with LCOS and required inotropic assistance. Four patients needed re-intubation due to significant LV dysfunction, and all four died within 14 days. One patient with LAD CE had developed an incomplete left bundle branch block. Nine patients developed atrial fibrillation (AF) which was medically managed. Two patients needed re-exploration for excessive drain output. Two patients developed postoperative stroke and two patients had acute kidney injury (AKI). The overall operative mortality was 5%.

The standard 12-lead ECG was taken on shifting the patient to ICU and repeated every day till the 5th day of the surgery. All ECGs were compared with previous ECG. Transthoracic two-dimensional echocardiography was performed the next day postprocedure in all patients and before discharge.

Serial monitoring of cardiac enzymes such as hs-cTnI and CPK-MB was performed at 6, 12, 24, 48, and 72 hours after surgery. The hs-cTnI values above >10 × 99th percentile (262 ng/L) and the CPK-MB value >25 ng/L were considered elevated. We observed an increase in cardiac markers in the early postoperative hours, which peaked at 24 hours and then began to decline progressively after 72 hours [Figure 2] and [Figure 3]. Although there was a tremendous rise noted in cardiac markers, patients were clinically stable.
Figure 2: Average value of high-sensitive troponin I (ng/L) in postoperative period

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Figure 3: Average value of CPK-MB (ng/L) in postoperative period

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  Discussion Top


Patients referred for CABG have diffuse CAD and may have had a history of PCI. Many studies have proven that overzealous use of catheter-based intervention in multi-vessel diseases with comorbid conditions had more atherosclerotic lesions distally with a higher rate of restenosis when they were offered CABG.[7]

CE was introduced in the mid-1950s to treat CAD as a primary treatment for improving blood flow to diseased artery.[4] The aim of the endarterectomy is to pull out the calcified atheroma and establish adequate revascularization. Complete revascularization is accompanied by improvement of cardiac contractility, lesser ventricular tachycardia, and enhanced ejection fraction.[8]

In this study, we have tried to demonstrate the perioperative outcomes of patients undergoing isolated CABG + CE.

The efficacy of off-pump CABG has established a new benchmark as an effective and safest way of coronary revascularization. In the last two decades, off-pump CABG has proven to be superior to on-pump CABG, as it reduces CPB time, transfusion rates, and ICU/hospital stays and improves cerebrovascular stroke outcomes.[9],[10] When possible, we conduct off-pump CABG in our institute to reduce myocardial damage in older patients with moderate-to-severe LV dysfunction.[11] Off-pump CE also helps the surgeon to extract atheromatous plaque easily from LAD territory due to continuous beating of the heart which augments retraction.[12] We performed off-pump CE in 100 patients with a conversion rate of 4% to on-pump surgery.[6]

Although multi-vessel endarterectomy has been recorded, the outcomes are inferior to single-vessel LAD endarterectomy.[6] In our study, we performed single-vessel EA in 85 and double-vessel EA in 15 patients. The LAD was the most common culprit vessel in 14 of the 15 patients. We noticed a high incidence of LCOS (40%) among double-vessel EA. Two patients expired due to multi-organ dysfunction and intractable arrhythmias.

Depending on the defining criteria, the incidence of PMI in CABG + CE has been reported to be as high as 20%.[13] Because of a lack of consensus on such matter, false-positive diagnosis may occur due to rise in cardiac biomarkers and ECG changes following incisions on cardiac chambers. Pathological Q-wave following cardiac surgery may be due to minor myocardial injury and infrequently correlated with MI.[14],[15]

At 6 hours after surgery, we found that 68 individuals had hs-cTnI and CPK-MB levels of 2631 ng/L and 51 ng/L, respectively. HscTnI and CPKMB levels were 7718 ng/L and 71 ng/L, respectively, at 24 hours. At 72 hours, it was discovered that the readings were gradually falling to 3778 and 40 ng/L, respectively [Figure 2] and [Figure 3]. Even though the patients in our study had significantly elevated levels of cardiac biomarkers, they were nonetheless stable.

Increased cardiac troponin level shows myocardial injury but does not predict the mechanism of injury.[16] Other causes of myocardial injury should be investigated if there is no clinical evidence of coronary ischemia. Other studies have shown that an isolated rise in cardiac biomarkers >20 × URL post-CABG may indicate graft failure and prompt action is needed in form of angiography and PCI.[17]

We were unable to compare postoperative ECG finding with preoperative ECG finding in the majority of patients with recent history of MI with ECG changes making it vulnerable for bias.

Various studies have confirmed no uniform correlation between cardiac markers and ECG changes to diagnose perioperative MI.[18] Rising trend of cardiac biomarkers is justified as evidence of acute myocardial injury during intraoperative period and postoperative period. As trajectory of cardiac enzymes is dynamic and bell shape with escalation of values within 24 h and diminishes then after gradually.[19] It is not enough to diagnose PMI purely based on cardiac biomarkers. There are no “gold standard” guidelines for diagnosing and validating perioperative MI in CABG +CE patients.[20]

The incidence of postoperative cardiac complications was comparable with other previously published studies (LCOS: 19%, re-exploration rate: 2%, IABP: 6%, arrhythmias: 9%, stroke: 2%, and AKI: 2%).[21],[22] The prevalence of variations in postoperative complication rate is justified by methods of patient selection, surgical techniques, methods, and criteria for definitions.[23],[24]

The perioperative mortality rate in our study was found to be 5%. Major factors attributing to higher mortality were CE in LAD territory, double CE, multiple comorbidities, recent AWMI, severe LV dysfunction, and old age.[8],[24],[25]

Anticoagulation and platelet inhibition

There has been documented evidence of adding another antithrombotic drug in addition to aspirin helps to maintain patency in diseased vessels in the presence of vulnerable coronary endothelium[26] As aspirin has little direct antithrombin effect, it is reasonable to add an anticoagulant drug, such as warfarin, to the regimen after CE.[27] We have established our protocol of starting injection heparin 5000 IU IV within 2 h of shifting the patients to ICU and it is continued every 6 hourly till the time patient stays in ICU. Dual antiplatelet therapy with aspirin and clopidogrel is given to all patients postoperatively. Warfarin is added and given for 3 months. INR is maintained between 2 and 2.5.[28] The addition of another anticoagulant had not complicated the postoperative course due to bleeding and cardiac tamponade as we had only two re-exploration due to excessive bleeding.[29]


  Conclusions Top


CABG + CE is an important procedure for complete revascularization in patients with diffuse CAD. In selected cases, endarterectomy can be performed at a low risk. It is a safe procedure for complete revascularization with acceptable mortality and morbidity.

  1. Cardiac biomarkers are found to be elevated in range of perioperative MI; however, it did not reflect in ECG changes and hemodynamics. There was no added morbidity
  2. Surgeons should not hesitate to perform CE.


Limitation

We believe there are several limitations to this study. We were unable to conduct a comparative evaluation between cabg and cabg +CE. It was not a long-term study to determine graft patency and patient outcomes. Second, postoperatively we could not conduct postoperative coronary angiography to validate our result and confirm the true nature of increased level of cardiac biomarkers.

Research involving human participants and/or animals

This study complies with the principles of The Declaration of Helsinki and was approved by the institutional ethics committee.

Informed consent

Informed consent was obtained from all individual participants included in the study.

Financial support and sponsorship

This study was financially supported by the U. N. Mehta Institute of Cardiology and Research Centre

Conflicts of interest

There are no conflicts of interest.

Ethical approval

The study involves human participants; the study has been approved by the appropriate Institutional Ethics Committee from UNMICRC, Ahmedabad(UNMICRC/CVTS/2018/22) and has been performed in accordance with the ethical standards as laid down in the 1964 Declaration of Helsinki. This article does not contain study performed on animals by any of the authors.

Authors' contributions

Dr. Herin Patel -Design, Aquisition, Dr. Ishan Gohil-Analysis, Interpretation, Drafting,Aquisition;Dr. Jignesh kothari,-Conceptualization, Design, Interpretation; Mr. Pratik Shah-Data Analysis.



 
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    Figures

  [Figure 1], [Figure 2], [Figure 3]
 
 
    Tables

  [Table 1], [Table 2], [Table 3]



 

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