Changing Pattern of Reoperative Coronary Artery Bypass Grafting: A 20-Year Study

A radiologist's guide to median sternotomy

Median sternotomy is widely recognised as the primary incision technique in cardiac surgery. This surgical procedure involves dividing the sternum to gain access to the heart and lungs, making it invaluable in correcting congenital heart defects. Furthermore, it is frequently employed in adult patients, particularly during coronary artery bypass graft (CABG) procedures. In this imaging review, we present a comprehensive overview of the pre-procedural assessment and various post-sternotomy complications encountered within our clinical experience at a tertiary cardiothoracic centre. The focus of this review is to outline the imaging features associated with mediastinal adhesions and establish the minimal safe distance between the sternum and common mediastinal structures when considering re-sternotomy. By providing visual examples, we aim to facilitate a better understanding of these key concepts. Moreover, we delve into a detailed discussion of a spectrum of postoperative complications that may arise following median sternotomy including those related to metalwork (sternal wire fracture), bone (sternal dehiscence, non-union and osteomyelitis), and soft tissue (abscess, haematoma).

Trends of re-operative coronary artery bypass grafting: A two-decade experience

BACKGROUND

The prevalence of redo coronary artery bypass grafting has markedly changed over the last two decades. We aim to assess the trends of redo coronary artery bypass grafting and clinical outcomes of redo coronary artery bypass grafting over two different periods.

METHODS

This is a retrospective, metachronous, observational study of patients who underwent redo coronary artery bypass grafting between January 1998 through December 2004 and January 2005 through September 2021 who were categorized into group 1 and group 2, respectively. The trends in the prevalence of redo coronary artery bypass grafting, and 30-day outcomes were analyzed.

RESULTS

A total of 261 patients underwent a redo coronary artery bypass grafting. Group 1 and group 2 included 114 and 147 patients, respectively. 62.59% of group 2 patients underwent off-pump coronary artery bypass grafting compared to 6.14% in group 1 (p < 0.01). The patients undergoing redo coronary artery bypass grafting in group 2 were significantly older (60.65 ± 7.78 years vs. 50.99 ± 7.66 years, p < 0.001) and were more likely to be hypertensive (49.66% vs. 29.82%, p < 0.001). There was no significant difference in the proportion of diabetes (p = 0.82), smoking (p = 0.24), dyslipidemia (p = 0.64), and preoperative myocardial infarction (p = 0.14). The proportion of patients who presented post-PCI was significantly higher in group 2 (27.89% vs. 10.53%, p < 0.001). There was also a shift in the usage of grafts from the left internal thoracic artery to the saphenous vein graft (p < 0.001).

CONCLUSION

The annual rate of redo coronary artery bypass grafting was declining but has now reached a plateau. The current outcomes of patients undergoing redo coronary artery bypass grafting are comparable to that of the earlier times despite a higher co-morbidity burden in patients of recent times.

Definitions of low cardiac output syndrome after cardiac surgery and their effect on the incidence of intraoperative LCOS: A literature review and cohort study

Objectives

Low cardiac output syndrome (LCOS) is a serious complication after cardiac surgery. Despite scientific interest in LCOS, there is no uniform definition used in current research and clinicians cannot properly compare different study findings. We aimed to collect the LCOS definitions used in literature and subsequently applied the definitions obtained to existing data to estimate their effect on the intraoperative LCOS incidences in adults, children and infants.

Design

This is a literature review, followed by a retrospective cohort study.

Setting

This is a single-institutional study from a university hospital in the Netherlands.

Participants

Patients from all ages undergoing cardiac surgery with cardiopulmonary bypass between June 2011 and August 2018.

Interventions

We obtained different definitions of LCOS used in the literature and applied these to data obtained from an anesthesia information management system to estimate intraoperative incidences of LCOS. We compared intraoperative incidences of LCOS in different populations based on age (infants, children and adults).

Measurements and main results

The literature search identified 262 LCOS definitions, that were applied to intraoperative data from 7,366 patients. Using the 10 most frequently published LCOS definitions, the obtained incidence estimates ranged from 0.4 to 82% in infants, from 0.6 to 56% in children and from 1.5 to 91% in adults.

Conclusion

There is an important variety in definitions used to describe LCOS. When applied to data obtained from clinical care, these different definitions resulted in large distribution of intraoperative LCOS incidence rates. We therefore advocate for standardization of the LCOS definition to improve clinical understanding and enable adequate comparison of outcomes and treatment effects both in daily care and in research.

Mid-Term Outcomes and Angiographic Patency of Redo Coronary Artery Bypass Grafting: A Comparison between Off-Pump and On-Pump Surgery

Background

We evaluated the mid-term outcomes and angiographic patency of redo coronary artery bypass grafting (CABG).

Methods

Of 2,851 patients who underwent isolated CABG at Seoul National University Hospital from 2000 to 2017, 88 underwent redo CABG. Patients’ mean age at redo CABG was 66.0±8.0 years. The mean interval between the first-time and redo CABG was 113.0±62.4 months. The mean follow-up duration was 86 months. Early and mid-term clinical outcomes were evaluated. Angiographic patency rates were evaluated early (1–2 days), 1 year, and 5 years after surgery. Comparative analyses between on-pump and off-pump CABG were also performed.

Results

The culprits for reoperation were previous grafts (65.6%), native coronary vessels (17.8%), and both (16.7%). Off-pump CABG was performed in 75 cases (85.2%), and the mean number of distal anastomoses was 1.8±0.8. The saphenous vein (39.7%) was used most frequently, followed by the right internal thoracic artery (28.4%), right gastroepiploic artery (21.3%), left internal thoracic artery (7.8%), and radial artery (2.8%). Operative mortality was 1.1%. The overall survival, cumulative incidence of cardiac death, and cumulative incidence of major adverse cardiac events were 71.3%,12.0%, and 23.3% at 5 years after surgery, respectively. The overall angiographic patency rates were 95.7%, 90.1%, and 92.2% on early, 1-year, and 5-year angiograms, respectively. The angiographic patency rates of saphenous vein grafts were 93.1%, 85.6%, and 91.3% on early, 1-year, and 5-year angiograms, respectively. No significant differences in clinical outcomes or angiographic patency rates were observed between the on-pump (n=13) versus off-pump (n=75) groups. Multivariable analysis revealed that age (hazard ratio [HR], 1.07; p=0.005) and chronic kidney disease (HR, 3.85; p=0.001) were risk factors for all-cause mortality.

Conclusion

Redo CABG could mostly be performed using the off-pump technique and did not show increased operative mortality and morbidities.

25 Years' Experience with Redo Operations in Cardiac Surgery-Third-Time Sternotomy Procedures

BACKGROUND

 Over the years, open heart surgery has become more complex, and especially reoperative surgery, more demanding. The risk of third-time or more sternotomy procedures is unclear.

METHODS

 We reviewed our institutional experience of 25 years based on two generations of cardiac surgeons in a German university medical center to document frequency, outcome, and complications of the various types of open heart procedures.

RESULTS

 Overall, we included 104 patients with a mean age of 64 ± 13 years. The EuroSCORE II (European System for Cardiac Operative Risk Evaluation) calculated an average mortality risk of 15.7 ± 15.4%. Subgroup comparison of isolated coronary artery bypass grafting (CABG), aortic valve replacement, and mitral valve replacement procedures did not delineate significantly different risk profiles except for the incidence of acute myocardial infarction, which was present in every second patient (53.3%) scheduled for CABG surgery. The time interval to previous surgery was 4.7 ± 6.3 years on average. Most frequent surgical procedures were valve operations, which were accomplished in 72 patients (69.2%), whereas coronary bypass surgery was performed in 23 patients (22.1%) only. Combined procedures were performed in 27 patients. Complex aortic arch replacement with a frozen elephant trunk procedure was necessary in six patients. Overall, 30-day survival was 81.7%.

CONCLUSION

 In conclusion, third-time and more sternotomy procedures offer acceptable outcome and should therefore be considered in appropriate patients.

Trends in Reoperative Coronary Artery Bypass Graft Surgery for Older Adults in the United States, 1998 to 2017

Background The likelihood of undergoing reoperative coronary artery bypass graft surgery (CABG) is important for older patients who are considering first-time CABG. Trends in the reoperative CABG for these patients are unknown. Methods and Results We used the Medicare fee-for-service inpatient claims data of adults undergoing isolated first-time CABG between 1998 and 2017. The primary outcome was time to first reoperative CABG within 5 years of discharge from the index surgery, treating death as a competing risk. We fitted a Cox regression to model the likelihood of reoperative CABG as a function of patient baseline characteristics. There were 1 666 875 unique patients undergoing first-time isolated CABG and surviving to hospital discharge. The median (interquartile range) age of patients did not change significantly over time (from 74 [69-78] in 1998 to 73 [69-78] in 2017); the proportion of women decreased from 34.8% to 26.1%. The 5-year rate of reoperative CABG declined from 0.77% (95% CI, 0.72%-0.82%) in 1998 to 0.23% (95% CI, 0.19%-0.28%) in 2013. The annual proportional decline in the 5-year rate of reoperative CABG overall was 6.6% (95% CI, 6.0%-7.1%) nationwide, which did not differ across subgroups, except the non-white non-black race group that had an annual decline of 8.5% (95% CI, 6.2%-10.7%). Conclusions Over a recent 20-year period, the Medicare fee-for-service patients experienced a significant decline in the rate of reoperative CABG. In this cohort of older adults, the rate of declining differed across demographic subgroups.

Outcomes of Reoperative Coronary Artery Bypass Graft Surgery in the United States

Background

There is a paucity of data on the trends and outcomes of reoperative coronary artery bypass graft (CABG) surgery during the current decade in the United States.

Methods and Results

We queried the National Inpatient Sample database (2002–2016) for all hospitalizations with isolated CABG procedure. We reported the temporal trends and outcomes of reoperative CABG versus primary CABG procedures. The main outcome was in‐hospital mortality. Among 3 212 768 hospitalizations with CABG, 46 820 (1.5%) had reoperative CABG. Over the 15‐year study period, there were no changes in the proportion of reoperative CABG (1.8% in 2002 versus 2.2% in 2016, P_tren=0.08), and the related in‐hospital mortality (3.7% in 2002 versus 2.7% in 2016, P_trend=0.97). Reoperative CABG was performed in patients with increasingly higher risk profile. Compared with primary CABG, hospitalizations for reoperative CABG were associated with higher in‐hospital mortality (3.2% versus 1.9%, P<0.001), cardiac arrest, cardiogenic shock, vascular complications, and respiratory complications. Among hospitalizations for reoperative CABG, the predictors of higher mortality included history of heart failure and chronic kidney disease.

Conclusions

In this 15‐year nationwide analysis, reoperative CABG procedures were increasingly performed in patients with higher risk profile. In‐hospital mortality rates were relatively low and did not change during the examined period. Compared with primary CABG, reoperative CABG is associated with higher in‐hospital mortality.

Repeat Coronary Bypass Surgery or Percutaneous Coronary Intervention After Previous Surgical Revascularization

OBJECTIVE

To assess long-term survival with repeat coronary artery bypass grafting (RCABG) or percutaneous coronary intervention (PCI) in patients with previous CABG.

METHODS

From January 1, 2000, through December 31, 2013, 1612 Mayo Clinic patients underwent RCABG (n=215) or PCI (n=1397) after previous CABG. The RCABG cohort was grouped by use of saphenous vein grafts only (n=75), or with additional arterial grafts (n=140); the PCI cohort by, bare metal stents (BMS; n=628), or drug-eluting stents (DES; n=769), and by the treated target into native coronary artery (n=943), bypass grafts only (n=338), or both (n=116). Multivariable regression and propensity score analysis (n=280 matched patients) were used.

RESULTS

In multivariable analysis, the 30-day mortality was increased in RCABG versus PCI patients (hazard ratio [HR], 5.32; 95%CI, 2.34-12.08; P<.001), but overall survival after 30 days improved with RCABG (HR, 0.72; 95% CI, 0.55-0.94; P=.01). Internal mammary arteries were used in 61% (129 of 215) of previous CABG patients and improved survival (HR, 0.82; 95% CI, 0.69-0.98; P=.03). Patients treated with drug-eluting stent had better 10-year survival (HR, 0.74; 95% CI, 0.59-0.91; P=.001) than those with bare metal stent alone. In matched patients, RCABG had improved late survival over PCI: 48% vs 33% (HR, 0.57; 95% CI, 0.35-0.91; P=.02). Compared with RCABG, patients with PCI involving bypass grafts (n=60) had increased late mortality (HR, 1.62; 95% CI, 1.10-2.37; P=.01), whereas those having PCI of native coronary arteries (n=80) did not (HR, 1.09; 95% CI, 0.75-1.59; P=.65).

CONCLUSION

RCABG is associated with improved long-term survival after previous CABG, especially compared with PCI involving bypass grafts.

Validation of the Coronary Artery Bypass Graft SYNTAX Score (Synergy Between Percutaneous Coronary Intervention With Taxus) as a Prognostic Marker for Patients With Previous Coronary Artery Bypass Graft Surgery After Percutaneous Coronary Intervention

BACKGROUND

The efficacy and prognosis of percutaneous coronary intervention (PCI) as secondary revascularization in patients with previous coronary artery bypass graft surgery remain uncertain.

METHODS AND RESULTS

We retrospectively evaluated 434 consecutive patients with previous coronary artery bypass graft surgery hospitalized for PCI between 2004 and 2011 (men 84%, age 71 (interquartile range, 66-76) years) and calculated the coronary artery bypass graft Synergy Between Percutaneous Coronary Intervention With Taxus score (CSS) before (baseline CSS) and after PCI (post-PCI CSS). Patients were divided into 2 groups based on median post-PCI CSS: low-score (≤23; n=217) and high-score groups (>23; n=217). Major adverse cardiovascular events (MACE) were defined as the composite of cardiovascular death, myocardial infarction, and unplanned repeat revascularization for myocardial ischemia. The median baseline and post-PCI CSS were 30 (interquartile range, 21-40) and 23 (interquartile range, 14.5-33.5), respectively. During a median follow-up of 69 months, the prevalence of MACE and cardiac death differed significantly between the 2 post-PCI CSS groups (MACE: low, 13.8%; high, 28.6%; P<0.001; cardiac death: low, 6.2%; high, 16.7%; P=0.002). In multivariable analysis, the high post-PCI CSS divided by the median was associated with substantially greater cumulative MACE (hazard ratio, 2.09; 95% confidence interval, 1.31-3.34; P=0.002) and cardiac death (hazard ratio, 2.02; 95% confidence interval, 1.03-3.98; P=0.042) compared with the low post-PCI CSS. Net reclassification improvement analysis revealed that post-PCI CSS resulted in significantly improved prediction of MACE and cardiac death compared with baseline CSS.

CONCLUSIONS

In this external validation study, the CSS was a potential prognostic factor after subsequent PCI, even for previous coronary artery bypass graft surgery patients.

Plasma homocysteine levels are related to medium-term venous graft degeneration in coronary artery bypass graft patients

Objective:

Saphenous venous grafts (SVGs) are established choices for coronary artery bypass grafting (CABG); however, their lumen patency is limited. Our goal was to investigate the risk factors of SVG degeneration.

Methods:

Seventy-five patients (mean age, 57.5±10.4 years) with 133 SVG conduits who had cardiac catheterization ≥1 year after CABG were selected; follow-up period was 67.6±36.8 months. Patients were divided into 3 groups according to angiographic status at follow up [intact: <20% (n=23); narrowed: 20–99% (n=24); and occluded (n=28)]. Baseline clinical conditions were evaluated in relation to follow-up angiography. As onset date of chronic total occlusions is usually uncertain, they arise typically from thrombotic lesions; thus, their value in evaluation is limited.

Results:

There were no significant differences between the 3 groups in clinical parameters. Linear correlation analysis found significant (p<0.01) positive connection of SVG disease (luminal diameter reduction 20–99%) with C-reactive protein (CRP) and homocysteine (Hcy), as well as between CRP and Hcy. Multiple regression analysis showed plasma Hcy level to be significantly related to graft diameter reduction normalized to time elapsed until angiography in narrowed grafts: 1 µmol/L increase of Hcy was associated with 0.053%/month decrease in lumen diameter (p<0.01; R²=0.428); extrapolating: +10 µmol/L higher Hcy level during 5 years is associated with 32.1% lumen reduction.

Conclusion:

Medium- to long-term SVG degeneration is related to elevated plasma total Hcy in patients with sub-occlusive graft stenosis, while in cases with intact SVGs, the beneficial local flow conditions may protect the grafts from degeneration.

Secondary revascularization after CABG surgery

CABG surgery is an effective way to improve symptoms and prognosis in patients with advanced coronary atherosclerotic disease. Despite multiple improvements in surgical technique and patient treatment, graft failure after CABG surgery occurs in a time-dependent fashion, particularly in the second decade after the intervention, in a substantial number of patients because of atherosclerotic progression and saphenous-vein graft (SVG) disease. Until 2010, repeat revascularization by either percutaneous coronary intervention (PCI) or surgical techniques was performed in these high-risk patients in the absence of specific recommendations in clinical practice guidelines, and within a culture of inadequate communication between cardiac surgeons and interventional cardiologists. Indeed, some of the specific technologies developed to reduce procedural risk, such as embolic protection devices for SVG interventions, are largely underused. Additionally, the implementation of secondary prevention, which reduces the need for reintervention in these patients, is still suboptimal. In this Review, graft failure after CABG surgery is examined as a clinical problem from the perspective of holistic patient management. Issues such as the substrate and epidemiology of graft failure, the choice of revascularization modality, the specific problems inherent in repeat CABG surgery and PCI, and the importance of secondary prevention are discussed.