Coronary artery bypass graft vs. percutaneous coronary angioplasty: CABG on the rebound?

Endothelin-1, endothelin receptor antagonists, and vein graft occlusion in coronary artery bypass surgery: 20 years on and still no journey from bench to bedside

The saphenous vein is the most commonly used bypass graft in patients with coronary artery disease. During routine coronary artery bypass, grafting the vascular damage inflicted on the vein is likely to stimulate the release of endothelin-1, a potent endothelium-derived vasoconstrictor that also possesses cell proliferation and inflammatory properties, conditions associated with vein graft failure. In both in vitro and in vivo studies, endothelin receptor antagonists reduce neointimal thickening. The mechanisms underlying these observations are multifactorial and include an effect on cell proliferation and cell/tissue damage. Much of the data supporting the beneficial action of endothelin-1 receptor antagonism at reducing intimal thickening and occlusion in experimental vein grafts were published over 20 years ago. The theme of the recent ET-16 conference in Kobe was "Visiting Old and Learning New". This short review article provides an overview of studies showing the potential of endothelin receptor antagonists to offer an adjuvant therapeutic approach for reducing saphenous vein graft failure and poses the question why this important area of research has not been translated from bench to bedside given the potential benefit for coronary artery bypass patients.

A systematic review of cost-effectiveness of percutaneous coronary intervention vs. surgery for the treatment of multivessel coronary artery disease in the drug-eluting stent era

Aims

The suitability of percutaneous coronary intervention (PCI), compared with coronary artery bypass grafting (CABG), for patients with complex multivessel coronary artery disease (MVCAD) remains a contentious topic. While the body of evidence regarding the clinical effectiveness of these revascularization strategies is growing, there is limited evidence concerning their long-term cost-effectiveness. We aim to critically appraise the body of literature investigating the cost-effectiveness of CABG compared with PCI using stents, and to assess the quality of the economic evidence available.

Methods and results

A systematic review was performed across six electronic databases; Medline, Embase, the NHS Economic Evaluation Database, the Database of Abstracts of Reviews of Effects, the health technology assessment database, and the Cochrane Library. All studies comparing economic attractiveness of CABG vs. PCI using bare-metal stents (BMS) or drug-eluting stents (DES) in balanced groups of patients were considered. Sixteen studies were included. These comprised studies of conventional CABG vs. BMS (n = 8), or DES (n = 4); off-pump CABG vs. BMS (n = 2), or DES (n = 1); and minimally invasive direct CABG vs. BMS (n = 2). The majority adopted a healthcare payer perspective (n = 14). The incremental cost-effectiveness ratios (ICERs) reported across studies varied widely according to perspective and time horizon. Favourable lifetime ICERs were reported for CABG in three trials. For patients with left main coronary artery disease, however, DES was reported as the dominant (more effective and cost-saving) strategy in one study.

Conclusion

Overall, CABG rather than PCI was the favoured cost-effective treatment for complex MVCAD in the long term. While the evidence base for the cost-effectiveness of DES compared with CABG is growing, there is a need for more evaluations adopting a societal perspective, and time horizons of a lifetime or 10 or more years.

Immediate Postoperative Complications in Patients Undergoing CABG; Investigating the Role of Prior Coronary Stenting

Introduction: Approximately 15 to 30% of patients undergoing percutaneous coronary intervention (PCI) will require repeated revascularization. There is an ongoing debate concerning the impact of prior PCI on subsequent coronary artery bypass graft (CABG) surgery. This study sought to compare immediate post-CABG complications between patients with and without previous coronary stenting.

Methods: A total of 556 CABG candidates including 73 patients with previous coronary stenting and 483 patients without prior stenting were enrolled in this retrospective-prospective study. Demographic information, cardiac markers (CK-MB, Troponin T), and postoperative data including inotrope administration, intra-aortic balloon pump (IABP) use, bleeding, pathological electrocardiography (ECG) changes, and overall complications were compared between the two groups.

Results: The mean age of the patients in stented group was significantly higher than that in unstented group (63.49±7.71 vs. 61.37±9.80 years, p=0.05). The mean serum level of Troponin T 12 h postoperation was significantly higher in the same group (323.26±33.16 vs. 243.30±11.52 ng/dL; p=0.03). Comparing the stented and unstented groups, the rates of inotrope use (17.8% vs. 7.2%; p=0.003), significant bleeding (15.1% vs. 4.3%; p=0.001), and overall complications (32.9% vs. 11.6%; odds ratio: 3.74 with 95% confidence interval of 2.13-6.55, p<0.001) were significantly higher in the former group. The association between overall complications and prior stenting was independent (odd ratio: 3.06). No significant connections were found between postoperative complications and stent number or type.

Conclusion: A positive history of previous coronary stenting significantly increases the risk of immediate post-CABG complications.

Percutaneous versus surgical interventions for coronary artery disease in those with diabetes mellitus

Diabetes mellitus (DM) is a metabolic disorder of multiple etiologies that causes long-term damage of various organs including the cardiovascular system. A consistent observation shows that DM amplifies the risk of cardiovascular events by 4- to 6-fold. Since coronary artery disease (CAD) in diabetic patients exhibits diffuse and accelerated lesions, invasive revascularization continues to be a challenge and has worse outcomes than patients without DM. Owing to the pathogenesis of DM and the presence of severe endothelial dysfunction, investigators have been trying to find new treatment modalities that could target the treatment of the disease rather than the treatment of the lesion. Until new treatment modalities are proven and gain acceptance, invasive revascularization remains to be the choice of treatment in such patients. The focus of this review is to compare the results of percutaneous coronary intervention (PCI) with coronary artery bypass grafting (CABG) for the treatment of stable CAD in patients with DM.

Similar survival 15 years after coronary artery surgery irrespective of left main stem stenosis

OBJECTIVES

To evaluate 15-year survival after coronary artery bypass grafting (CABG) in relation to grade left main stenosis (LMS) and right coronary artery (RCA) obstruction.

DESIGN

Coronary angiographic findings were prospectively collected in 977 patients who had CABG for stable angina during 1994-1995 and were included in the Swedish Coronary Revascularization - Swedish Council of Technology Assessment study.

RESULTS

Significant LMS was present in one fifth of the patients and significant RCA obstruction was found in 61% of those with LMS and in 68% of patients without LMS. The patients were categorized as no LMS (Group I), LMS without RCA obstruction (Group II) or significant LMS with significant right coronary artery (RCA) obstruction (Group III). Early mortality did not differ in the three groups and was 1.2, 1.2% and 0.8% in group I, II and III, respectively. Corresponding survival at 15 years was similar 51%, 47% and 47%, respectively. In multivariable analysis older age, smoking, severe angina, positive stress test, hypertension, diabetes mellitus and ejection fraction < 50% were risk factors for death at 15 years.

CONCLUSIONS

Death 15 years after CABG correlated to clinical variables but was not predicted from presence of LMS with or without significant associated RCA obstruction.

Operating room cost for coronary artery bypass graft procedures: does experience or severity of illness matter?

OBJECTIVE

Very few studies have addressed the magnitude of the effect of the condition of the patients and the surgical volume on possible cost savings in coronary artery bypass grafting (CABG). The objectives of this study were to analyse and compare the costs of the CABG operating room (OR) between two hospitals, and to examine the effect of surgical volume and severity of illness on the OR costs.

METHOD

The charts of patients who were diagnosed with coronary artery disease and who underwent CABG at two acute tertiary care hospitals in 2004 were reviewed retrospectively. Data on patient demographics, length of stay (LOS) and the American Society of Anesthesiologists Physical Status (ASAPS) score were extracted from the patient records. Cost information was obtained from detailed billing charges and from the financial accounting divisions of the hospitals.

RESULTS

The high-volume hospital consumed fewer resources than the low-volume hospital (US$5411 vs. US$6407). The age of the patients, surgical volume, operating hours and LOS were associated with the OR cost. Patient age and ASAPS score, hospital, and surgical volume were associated with LOS. Patient age, the number of diseased vessels, doctor volume and pump used or not were positively associated with the operation time. The LOS and the operation time may be the mediators of the relationship between the ASAPS score and cost, and may moderate the association of volume with cost.

CONCLUSIONS

This study supports the saying that 'practice makes perfect'. The knowledge and experience of the surgeons and the hospital management team are equally important in the supply of health services to patients with varying severity of illness, and are needed to maintain the competitive position of a hospital.

Correlates of coronary angiography in patients with stable angina and geographical differences in its utilisation: the ACTION experience

BACKGROUND

Utilisation of coronary angiography (CAG) varies between different countries. For patients with stable angina, the present study aimed to assess whether such differences could be explained by differences in patient characteristics, and whether these differences were related to outcome.

METHODS

Using data from the ACTION trial, which compared long-acting nifedipine GITS with placebo in 7665 patients with stable angina from 19 countries, we determined by country the ratio of the observed (O) and the expected (E, based on multivariate models) number of patients who had a history of CAG before entry, or underwent CAG during a mean follow-up of 5 years. Similarly, we determined corresponding O/E ratios for the combined occurrence of any death, myocardial infarction (MI) or debilitating stroke (DS) during follow-up.

RESULTS

O/E ratios for a history of CAG before entry ranged from 0.68 [95% confidence interval (CI) 0.60-0.77) for Sweden to 1.43 (95%CI 1.36-1.44) for Belgium, and were significantly correlated (p=0.04) to the corresponding O/E ratios for CAG during follow-up. The combined O/E ratio for CAG either before entry or during follow-up was not correlated (p=0.7) to the O/E for death, MI or DS, which ranged from 0.38 (95%CI undetermined) for Austria to 1.34 (95%CI 0.80-1.89) for France.

CONCLUSIONS

The degree to which CAG is utilised in patients with stable angina varies between countries but is not related to the occurrence of death, MI or stroke. This supports the notion that percutaneous coronary intervention does not reduce the risk of events.

Racial and ethnic disparities in access to higher and lower quality cardiac surgeons for coronary artery bypass grafting

To determine whether Hispanic and African-American patients are treated by cardiac surgeons with better or worse risk-standardized outcomes than surgeons of white patients, clinical data from the Massachusetts Data Analysis Center Registry were analyzed on all patients who underwent isolated coronary artery bypass grafting (CABG) from 2002 to 2004 by surgeons who performed >or=10 operations. Surgeons were divided into 4 groups based on their risk-standardized 30-day all-cause mortality incidence rates (top decile, top quartile, bottom quartile, and bottom decile). A total of 12,973 isolated CABGs were performed by 56 surgeons for 11,800 whites (91%), 413 Hispanics (3.2%), and 251 African-Americans (1.9%). White patients were more likely to be treated by surgeons in the top decile than by surgeons in the bottom decile (odds ratio [OR] 1.37, 95% confidence interval [CI] 1.07 to 1.76). In contrast, Hispanic patients were almost 3 times more likely to be treated by surgeons in the bottom decile compared with the top decile (OR 2.85, 95% CI 1.82 to 4.47). Compared with whites, Hispanic patients were about 1/2 as less likely to be treated by surgeons in the top decile (OR 0.51, 95% CI 0.35 to 0.75). African-American and white patients were similarly likely to be treated by surgeons in the top- and bottom-quality performance groups. In conclusion, Hispanics undergoing isolated CABG in Massachusetts were more likely to be operated on by cardiac surgeons with higher risk-standardized mortality rates than by surgeons with lower rates.