Impact on contrast, fluoroscopy, and catheter utilization from knowing the coronary artery bypass graft anatomy before diagnostic coronary angiography

The value of non-invasive computed tomography coronary angiography in imaging patients with coronary artery bypass grafts

INTRODUCTION

Invasive coronary angiography (ICA) is associated with higher complication rates in patients following coronary artery bypass surgery (CABG). CT coronary angiography (CTCA) has emerged as an attractive alternative. We assessed the impact of CTCA on subsequent ICA.

METHODS

We identified 213 CABG patients undergoing CTCA between 2015 and 2018. In 151 the indication was suspected recurrence of angina. We then identified patients undergoing ICA within 1 year of CTCA.

RESULTS

CTCA obviated the need for ICA in 115 cases (76%). CTCA was better at identifying targets for percutaneous coronary intervention (PCI) to saphenous vein grafts (SVG's) than to native vessels (89% vs 47%). 7 out of 10 lesions of "probable" significance by CTCA proved flow-limiting, and 4 out of 13 "indeterminate" lesions. CTCA concordance was 97% for left internal mammary (LIMA) grafts.

CONCLUSION

CTCA directed management in a majority of patients without ICA. It identified a cohort of patients likely to be candidates for SVG PCI, but was less effective in identifying PCI targets in the native vessels. CTCA renders invasive LIMA cannulation redundant unless a target lesion is suspected.

The sternal wire code; Solving the problem of missing coronary artery bypass graft records during cardiac catheterization

Background

The sternal wire code records details of coronary artery bypass surgery (CABG) inside patients, based on the orientation of wires used for sternal closure. Visible on X-ray, the code overcomes the problem of missing graft-notes needed before repeat angiography. We determined (i) the potential value (ii) acceptability and (iii) accuracy of the code in practice.

Methods

(i) Consecutive coronary angiogram reports (2015–2016 Barts, London) were reviewed to identify patients with previous CABG and those with and without graft-notes before angiography. (ii) UK surgeons were surveyed on whether they would insert the code during CABG. (iii) A clinician, blinded to operative details, interpreted 16 post-CABG X-rays, 8 with the code and 8 without.

Results

(i) Of 6483 angiography patients, 559 had previous CABG (9.2% (8.5–10%)). Graft-notes were missing in 91/559 (15.1% (12–18%)); almost all (88/91) among patients with acute myocardial infarction. (ii) In the survey, 66/71surgeons (93% (84–98%)) were willing to use the code. (iii) In the accuracy test, all coded X-rays were identified and 28/28 grafts correctly interpreted (p < 0.001).

Conclusions

About 1 in 6 patients with previous CABG, who require emergency coronary angiography, undergo this procedure without graft-notes and would benefit from the sternal wire code which appears clinically acceptable and accurate.

Predictors of Excess Patient Radiation Exposure During Chronic Total Occlusion Coronary Intervention: Insights From a Contemporary Multicentre Registry

BACKGROUND

High patient radiation dose during chronic total occlusion (CTO) percutaneous coronary intervention (PCI) might lead to procedural failure and radiation skin injury.

METHODS

We examined the association between several clinical and angiographic variables on patient air kerma (AK) radiation dose among 748 consecutive CTO PCIs performed at 9 experienced US centres between May 2012 and May 2015.

RESULTS

The mean age was 65 ± 10 years, 87% of patients were men, and 35% had previous coronary artery bypass graft surgery (CABG). Technical and procedural success was 92% and 90%, respectively. The median patient AK dose was 3.40 (interquartile range, 2.00-5.40) Gy and 34% of the patients received > 4.8 Gy (high radiation exposure). In univariable analysis male sex (P = 0.016), high body mass index (P < 0.001), history of hyperlipidemia (P = 0.023), previous CABG (P < 0.001), moderate or severe calcification (P < 0.001), tortuosity (P < 0.001), proximal cap ambiguity (P = 0.001), distal cap at a bifurcation (P = 0.006), longer CTO occlusion length (P < 0.001), blunt/no blunt stump (P < 0.001), and centre (P < 0.001) were associated with higher patient AK dose. In multivariable analysis high body mass index (P < 0.001), previous CABG (P = 0.005), moderate or severe calcification (P = 0.005), longer CTO occlusion length (P < 0.001), and centre (P < 0.001) were independently associated with higher patient AK dose.

CONCLUSIONS

Approximately 1 in 3 patients who undergo CTO PCI receive high AK radiation dose (> 4.8 Gy). Several baseline clinical and angiographic characteristics can help predict the likelihood of high radiation dose and assist with intensifying efforts to reduce radiation exposure for the patient and the operator.

Value of Image Fusion in Coronary Angiography for the Detection of Coronary Artery Bypass Grafts

BACKGROUND

Coronary angiography is more complex in patients with coronary artery bypass grafts (CABG). Image fusion is a new technology that allows the overlay of a computed tomography (CT) three-dimension (3D) model with fluoroscopic images in real time.

METHODS AND RESULTS

This single-center prospective study included 66 previous CABG patients undergoing coronary and bypass graft angiography. Image fusion coronary angiographies (fusion group, 20 patients) were compared to conventional coronary angiographies (control group, 46 patients). The fusion group included patients for whom a previous chest CT scan with contrast was available. For patients in this group, aorta and CABG were reconstructed in 3D from CT acquisitions and merged in real time with fluoroscopic images. The following parameters were compared: time needed to localize the CABG; procedure duration; air kerma (AK); dose area product (DAP); and volume of contrast media injected. Results are expressed as median. There were no significant differences between the 2 groups in patient demographics and procedure characteristics (access site, number of bypass to be found, and interventional cardiologist's experience). The time to localize CABG was significantly shorter in the fusion group (7.3 versus 12.4 minutes; P=0.002), as well as the procedure duration (20.6 versus 25.6 minutes; P=0.002), AK (610 versus 814 mGy; P=0.02), DAP (4390 versus 5922.5 cGy·cm(2); P=0.02), and volume of iodinated contrast media (85 versus 116 cc; P=0.002).

CONCLUSIONS

3D image fusion improves the CABG detection in coronary angiography and reduces the time necessary to localize CABG, total procedure time duration, radiation exposure, and volume of contrast media.

A randomized comparison of the transradial and transfemoral approaches for coronary artery bypass graft angiography and intervention: the RADIAL-CABG Trial (RADIAL Versus Femoral Access for Coronary Artery Bypass Graft Angiography and Intervention)

OBJECTIVES

This study sought to compare and contrast use and radiation exposure using radial versus femoral access during cardiac catheterization of patients who had previously undergone coronary artery bypass graft (CABG) surgery.

BACKGROUND

Limited information is available on the relative merits of radial compared with femoral access for cardiac catheterization in patients who had previously undergone CABG surgery.

METHODS

Consecutive patients (N = 128) having previously undergone CABG surgery and referred for cardiac catheterization were randomized to radial or femoral access. The primary study endpoint was contrast volume. Secondary endpoints included fluoroscopy time, procedure time, patient and operator radiation exposure, vascular complications, and major adverse cardiac events. Analyses were by intention-to-treat.

RESULTS

Compared with femoral access, diagnostic coronary angiography via radial access was associated with a higher mean contrast volume (142 ± 39 ml vs. 171 ± 72 ml, p < 0.01), longer procedure time (21.9 ± 6.8 min vs. 34.2 ± 14.7 min, p < 0.01), greater patient air kerma (kinetic energy released per unit mass) radiation exposure (1.08 ± 0.54 Gy vs. 1.29 ± 0.67 Gy, p = 0.06), and higher operator radiation dose (first operator: 1.3 ± 1.0 mrem vs. 2.6 ± 1.7 mrem, p < 0.01; second operator 0.8 ± 1.1 mrem vs. 1.8 ± 2.1 mrem, p = 0.01). Fewer patients underwent ad hoc percutaneous coronary intervention (PCI) in the radial group (37.5% vs. 46.9%, p = 0.28) and radial PCI procedures were less complex. The incidences of the primary and secondary endpoints was similar with femoral and radial access among PCI patients. Access crossover was higher in the radial group (17.2% vs. 0.0%, p < 0.01) and vascular access site complications were similar in both groups (3.1%).

CONCLUSIONS

In patients who had previously undergone CABG surgery, transradial diagnostic coronary angiography was associated with greater contrast use, longer procedure time, and greater access crossover and operator radiation exposure compared with transfemoral angiography. (RADIAL Versus Femoral Access for Coronary Artery Bypass Graft Angiography and Intervention [RADIAL-CABG] Trial; NCT01446263).

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.

Percutaneous coronary intervention in native arteries versus bypass grafts in prior coronary artery bypass grafting patients: a report from the National Cardiovascular Data Registry

OBJECTIVES

This study examined a large registry to determine the frequency, predictors, and outcomes of native coronary artery versus bypass graft percutaneous coronary intervention (PCI) in patients with prior coronary artery bypass graft surgery (CABG).

BACKGROUND

The PCI target vessel and corresponding outcomes in prior CABG patients are poorly studied.

METHODS

We analyzed the frequency and factors associated with native versus bypass graft PCI in prior CABG patients undergoing PCI between January 1, 2004, and June 30, 2009, in the National Cardiovascular Data Registry (NCDR) CathPCI Registry. Generalized estimating equations logistic regression modeling was used to generate independent variables associated with native versus bypass graft PCI and in-hospital mortality.

RESULTS

During the study period, PCI in prior CABG patients represented 17.5% of the total PCI volume (300,902 of 1,721,046). The PCI target was a native coronary artery in 62.5% and a bypass graft in 37.5%: saphenous vein graft (SVG) (104,678 [34.9%]), arterial graft (7,517 [2.5%]), or both arterial graft and SVG (718 [0.2%]). Compared with patients undergoing native coronary artery PCI, those undergoing bypass graft PCI had higher-risk characteristics and more procedural complications. On multivariable analysis, several parameters (including graft stenosis and longer interval from CABG) were associated with performing native coronary PCI, and bypass graft PCI was associated with higher in-hospital mortality (adjusted odds ratio: 1.22, 95% confidence interval: 1.12 to 1.32).

CONCLUSIONS

Most PCIs performed in prior CABG patients are done in native coronary artery lesions. Compared with native coronary PCI, bypass graft PCI is independently associated with higher in-hospital mortality.