Coronary angioplasty versus repeat coronary artery bypass grafting for patients with previous bypass surgery

Percutaneous coronary intervention versus repeat surgical revascularization in patients with prior coronary artery bypass grafting: A systematic review and meta-analysis

Objectives

Repeat coronary artery bypass grafting (RCABG) and percutaneous coronary intervention (PCI) are both used for the treatment of symptomatic patients with coronary artery disease and prior CABG, but the optimal treatment strategy remains unknown. We sought to perform a systematic review and meta-analysis to compare operative and follow-up outcomes following RCABG versus PCI in patients with prior CABG.

Methods

Medline and Embase were searched for studies comparing RCABG versus PCI. The primary outcome was follow-up mortality, and secondary outcomes were follow-up repeat revascularization, operative mortality, periprocedural stroke, and myocardial infarction. Time-to-event outcomes were summarized as incidence rate ratios, whereas operative outcomes were summarized as odds ratios. A random effect meta-analysis was performed. Individual patient survival data was extracted from available survival curves and reconstructed using restricted mean survival time.

Results

Among 2982 articles, 7 studies (9945 patients) were included. In the aggregated data meta-analysis, there was no difference in follow-up survival between RCABG and PCI (incidence rate ratio, 1.02; 95% CI, 0.83-1.25); however, restricted mean survival time analysis of individual data showed a survival benefit for RCABG over PCI (0.7 years; 95% CI, 0.23-1.19 years; P = .004). PCI was found to have a higher incidence rate of follow-up need for repeat revascularization (incidence rate ratio, 1.61; 95% CI, 1.16-2.23), but lower odds for operative mortality and stroke. No difference in the odds for myocardial infarction was found.

Conclusions

In patients with prior CABG, PCI is associated with better operative outcomes, but RCABG is associated with better survival and freedom from repeat revascularization at follow-up.

Revascularization for Coronary Artery Disease: Principle and Challenges

Coronary revascularization is the most important strategy for coronary artery disease. This review summarizes the current most prevalent approaches for coronary revascularization and discusses the evidence on the mechanisms, indications, techniques, and outcomes of these approaches. Targeting coronary thrombus, fibrinolysis is indicated for patients with diagnosed myocardial infarction and without high risk of severe hemorrhage. The development of fibrinolytic agents has improved the outcomes of ST-elevation myocardial infarction. Percutaneous coronary intervention has become the most frequently performed procedure for coronary artery disease. The evolution of stents plays an important role in the result of the procedure. Coronary artery bypass grafting is the most effective revascularization approach for stenotic coronary arteries. The choice of conduits and surgical techniques are important determinants of patient outcomes. Multidisciplinary decision-making should analyze current evidence, considering the clinical condition of patients, and determine the safety and necessity for coronary revascularization with either PCI or CABG. For coronary artery disease with more complex lesions like left main disease and multivessel disease, CABG results in more complete revascularization than PCI. Furthermore, comorbidities, such as heart failure and diabetes, are always correlated with adverse clinical events, and a routine invasive strategy should be recommended. For patients under revascularization, secondary prevention therapies are also of important value for the prevention of subsequent adverse events.

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.

Factors associated with switching between low and super utilization in the surgical population: A study in medicare expenditure

BACKGROUND

Considered the top 5% of healthcare utilizers, "super-utilizers" are estimated to consume as much as 40-55% of all healthcare costs. The aim of this study was to identify factors associated with switching between low- and super-utilization.

METHODS

Low and super-utilizers who underwent abdominal aortic aneurysm (AAA) repair, coronary artery bypass graft (CABG), colectomy, total hip arthroplasty (THA), total knee arthroplasty (TKA), or lung resection between 2013 and 2015 were identified from 100% Medicare Inpatient Standard Analytic Files.

RESULTS

Among 1,049,160 patients, 788,488 (75.1%) and 21,700 (2.1%) patients were low- or super-utilizers prior to surgery, respectively. Among patients who were super-utilizers before surgery, 23% remained super-utilizers post-operatively, yet 26.8% patients became low-utilizers after surgery. Factors associated with moving from low-to super-utilization in the pre-versus post-operative setting included AAA repair, higher Charlson, and pulmonary failure. In contrast, pre-operative super-utilizers who became low-utilizers in the post-operative setting were less likely to be African American or have undergone CABG.

CONCLUSION

While 3% of pre-operative low-utilizers became super-utilizers likely due to complications, nearly one quarter of all pre-operative super-utilizers became low-utilizers following surgery suggesting success of the surgery to resolve underlying conditions associated with preoperative super-utilization.

Management and Prevention of Saphenous Vein Graft Failure: A Review

Coronary artery bypass grafting (CABG) remains a vital treatment for patients with multivessel coronary artery disease (CAD), especially diabetics. The long-term benefit of the internal thoracic artery graft is well established and remains the gold standard for revascularization of severe CAD. It is not always possible to achieve complete revascularization through arterial grafts, necessitating the use of saphenous vein grafts (SVG). Unfortunately, SVGs do not have the same longevity, and their failure is associated with significant adverse cardiac outcomes and mortality. This paper reviews the pathogenesis of SVG failure, highlighting the difference between early, intermediate, and late failure. It also addresses the different surgical techniques that affect the incidence of SVG failure, as well as the medical and percutaneous prevention and treatment options in contemporary practice.

Comparison of sirolimus-eluting stents with paclitaxel-eluting stents in saphenous vein graft intervention (from a multicenter Southern California Registry)

This study was designed to compare the safety and efficacy of sirolimus-eluting stents (SESs) to paclitaxel-eluting stents (PESs) in percutaneous intervention of saphenous vein graft (SVG) lesions. SVGs develop atherosclerosis at high rates and often require repeat revascularization. Percutaneous intervention with drug-eluting stents has become the preferred method of revascularization due to higher restenosis with bare metal stents and increased morbidity and mortality with repeat coronary artery bypass grafting. We sought to compare the rate of major adverse cardiac events and stent thrombosis between SESs and PESs in patients undergoing SVG intervention. A multicenter analysis of 172 patients with SVG lesions treated with SESs or PESs was performed. The 30-day and 1-year clinical outcomes of 102 patients receiving SESs were compared to those of 70 patients receiving PESs. There was no significant difference in baseline demographic, angiographic, and procedural characteristics between the SES and PES treatment groups. There was no statistical difference in major adverse cardiac events at 30 days and at 1 year (hazard ratio [HR] 1.58, 95% confidence interval [CI] 0.77 to 3.23, log-rank p = 0.21). There was also no difference in survival (HR 1.28, 95% CI 0.39 to 4.25, log-rank p = 0.69) or target vessel revascularization (HR 2.54, 95% CI 0.84 to 7.72, log-rank p = 0.09). In conclusion, this multicenter analysis of real-world patients demonstrated that SESs and PESs have similar clinical outcomes when used in SVG intervention.

Nonrevascularizable coronary artery disease following coronary artery bypass graft surgery: a population-based study in Olmsted County, Minnesota

AIMS

Therapeutic options for patients with recurrent cardiac ischemia after coronary artery bypass surgery may be limited and some patients may be considered nonrevascularizable. To further the understanding of this patient cohort, we performed a population-based study of post-coronary bypass patients who developed recurrent angina.

METHODS AND RESULTS

Patients who underwent coronary artery and bypass graft angiography at Mayo Clinic from 2001 to 2005 were identified. Medical records were reviewed to determine indication for angiography, and angiographic analysis was performed in all patients. Among 133 000 residents of Olmsted County, Minnesota, 347 post-bypass patients with angina underwent coronary angiography from 2001 to 2005. Of these, 177 patients received further revascularization (145 percutaneous coronary intervention and 32 redo coronary artery bypass grafting) and the remaining 170 patients were managed medically. Revascularization was not associated with improvement in all-cause or cardiac mortality. Multivariate analysis identified renal dysfunction, diabetes, and severe left ventricular dysfunction but not the lack of revascularization as predictors of mortality.

CONCLUSION

In this population-based study, we identified a yearly incidence range of 17.9-33.2 patients with nonrevascularizable angina after coronary artery bypass grafting per 100 000 population. Further revascularization was not associated with improved mortality or morbidity. Attempts to develop therapeutics for this population must consider the incidence and outcomes of this cohort.

Drug-eluting stents versus bare metal stents for narrowing in saphenous vein grafts

Conflicting data exist regarding an advantage of drug-eluting stents (DES) over bare metal stents (BMS) in catheter-based treatment of saphenous vein graft (SVG) stenoses. This study was undertaken to compare the efficacy of these modalities in that lesion subset. The DES group consisted of 138 cases with 183 lesions (sirolimus-eluting stents, n = 117; paclitaxel-eluting stents, n = 66) and the BMS group consisted of 344 cases with 478 lesions that were followed to 1 year. We examined a composite end point that comprised death, Q-wave myocardial infarction, and target lesion revascularization. More BMS were deployed per patient (p <0.001) and the diameters of BMS deployed was significantly greater (p <0.001). Peak postprocedure values of creatine kinase-MB (p = 0.003) and troponin I (p = 0.05) were higher in BMS. At 1 year there was no significant superiority of DES over BMS with regard to hard end points (death and Q-wave myocardial infarction). In conclusion, this study indicates that both DES and BMS for SVG disease provide acceptably safe and efficacious results, but unlike the case in native coronary arteries, DES use does not reduce the frequency of the need for repeat revascularization.

Evidence based medicine: role of multidetector CT in the follow-up of patients receiving coronary artery bypass graft

PURPOSE

The aim of this study was to define the role of multidetector computed tomography (MDCT) in the follow-up assessment of patients undergoing coronary artery bypass grafting (CABG) using an evidence-based medicine (EBM) approach.

MATERIALS AND METHODS

We performed a literature search of the most reputable studies published in the period 1990-2005 on the clinical follow-up of patients after myocardial revascularisation by CABG. Relevant studies were ranked according to levels of evidence using EBM criteria. A similar search was also conducted on the Internet to identify and review the guidelines posted by the major international scientific societies.

RESULTS

A total of 29 papers meeting the basic reliability requirements of EBM were identified. The reported sensitivity and specificity for electrocardiogram (ECG) testing, stress echocardiography and radionuclide myocardial perfusion imaging were 45% and 82%, 86% and 90%, and 68% and 84%, respectively. All 16 CT studies (one retrospective, the remaining prospective) were validation studies comparing MDCT with conventional coronary angiography. The total number of patients and graft segments studied were 705 and 1,974, respectively. The total number of assessable graft segments were 62%-100%, with a sensitivity and specificity of 75%-100% and 76.9%-100%, respectively.

CONCLUSIONS

The applications of MDCT in the follow-up assessment of patients after CABG are derived from indirect evidence only. The efficacy of the method should be evaluated in randomised clinical trials comparing MDCT not only with conventional coronary angiography but also with other noninvasive stress imaging methods. On the basis of the clinical evidence reported in the literature, the indications for the use of MDCT are still limited. In our view, the completion of such randomised trials combined with the development of new-generation scanners is required to correctly define the role of MDCT in the follow-up assessment of patients who have undergone CABG.

Six-month outcomes after percutaneous intervention for lesions in aortocoronary saphenous vein grafts using distal protection devices: results from the FIRE trial

BACKGROUND

The filter-based FilterWire EX (Boston Scientific, Natick, MA) embolic protection system and the GuardWire (Medtronic, Santa Rosa, CA) balloon occlusion and aspiration device have been previously shown to reduce periprocedural complication rates of percutaneous coronary intervention for saphenous vein graft (SVG) disease and are considered the standard of care in this setting. The late clinical course after treatment with these devices has not been reported.

METHODS

In the FIRE trial, 651 patients undergoing SVG intervention were randomized to either the FilterWire EX or GuardWire. Six-month rates of the primary end point (composite major adverse cardiac events [MACE]) and its components (death, myocardial infarction [MI], or target vessel revascularization) were studied.

RESULTS

MACE at 30 days occurred in 9.9% of patients randomized to the FilterWire EX compared with 11.6% with the GuardWire, P = .53. By 6 months, MACE had increased to 19.3% and 21.9% in FilterWire EX and GuardWire groups, respectively, (relative risk 0.88, 95% CI 0.65-1.19; P = .44). All-cause 6-month mortality in the entire population was 3.5% (3.0% with FilterWire EX vs 4.1% with GuardWire, P = .53, with all deaths occurring after hospital discharge). MI occurred in 12.0% of patients at 6 months (12.1% vs 11.9% with the FilterWire EX and GuardWire, respectively, P = .99), and target vessel revascularization was required in 9.1% (8.2% vs 10.0%, respectively, P = .42).

CONCLUSIONS

SVG intervention with the FilterWire EX and GuardWire distal protection devices resulted in similar outcomes at 6 months, although the clinical course after hospital discharge was not benign, with significant rates of death, MI, and repeat intervention.

Predictors of revascularization method and long-term outcome of percutaneous coronary intervention or repeat coronary bypass surgery in patients with multivessel coronary disease and previous coronary bypass surgery

AIMS

The optimal revascularization strategy in patients with symptomatic multivessel coronary artery disease (CAD) and previous coronary artery bypass grafting (CABG) remains unknown.

METHODS AND RESULTS

We evaluated all patients with previous CABG undergoing isolated, non-emergency multivessel revascularization between 1 January 1995 and 31 December 2000. The analysis concentrated on the independent predictors of the revascularization method, as well as on long-term mortality and its predictors, after calculating a propensity score for the method of revascularization. There were 2191 patients (1487 with reoperation and 704 with percutaneous coronary intervention, PCI) in the study. The most important factors in choosing reoperation were presence of more diseased or occluded grafts, previous infarction, lower ejection fraction (EF), longer interval from first CABG, and more total occlusions of native arteries, as well as absence of a patent mammary graft. The distribution of the propensity score was skewed towards the two extremes. At 5 years, the unadjusted cumulative survival was 79.5% for CABG and 75.3% for PCI, P=0.008. After adjustment for the propensity score for PCI vs. CABG, PCI was associated with a hazard ratio of 1.47 (0.94-2.28), P=0.09. The most powerful predictors of mortality were higher age and lower EF.

CONCLUSION

The choice of the revascularization method in patients with previous CABG is dictated mostly by anatomical considerations and less by clinical characteristics. In contrast, clinical characteristics predominantly affect long-term outcome, whereas the method of revascularization has a limited effect. A randomized clinical trial addressing this important segment of the population with ischaemic heart disease is warranted.

Decreasing significance of left ventricular dysfunction and reoperative surgery in predicting coronary artery bypass grafting–associated mortality: A twelve-year study

OBJECTIVES

Patients undergoing coronary artery bypass grafting are older and have greater comorbidity than those operated on previously. We evaluated the changes in the predictors of in-hospital mortality among patients undergoing coronary artery bypass grafting during the last 12 years.

METHODS

Data on demographic characteristics, preoperative risk factors, operative variables, and hospital outcomes were collected prospectively for all patients undergoing isolated coronary artery bypass grafting at a single institution from January 1, 1990, to December 31, 2001. To examine the effect of time on patient risk profiles and outcomes, we divided patients into three groups according to year of operation (1990-1993 n = 5171, 1994-1997 n = 5977, 1998-2001 n = 6893).

RESULTS

In-hospital mortality declined from 2.4% (1990-1993) to 1.2% (1998-2001, P <.0001). Left ventricular dysfunction, increasing age, female gender, hypertension, diabetes, cardiogenic shock, congestive heart failure, peripheral vascular disease, reoperative coronary artery bypass grafting, left main disease, and urgent surgery independently predicted in-hospital mortality in the entire cohort of 18,041 patients. Severe left ventricular dysfunction was the most significant predictor of in-hospital mortality in the 12-year cohort, but it had a declining influence with time (1990-1993 odds ratio 7.1, 1994-1997 odds ratio 5.1, 1998-2001 not statistically significant) because of improving outcomes. Reoperative coronary artery bypass grafting similarly decreased in significance as a predictor of mortality. Emergency coronary artery bypass grafting was performed less frequently in recent years, but the requirement for emergency surgery carried an increasing odds ratio for mortality.

CONCLUSIONS

Despite increasing patient age and comorbidity, improvements in perioperative management have reduced the significance of severe left ventricular dysfunction and reoperative coronary artery bypass grafting but not emergency surgery as predictors of in-hospital mortality.

Enhanced External Counterpulsation for the relief of angina in patients with diabetes: safety, efficacy and 1-year clinical outcomes

BACKGROUND

Patients with diabetes are at greater risk for coronary events, yet they are less likely to benefit from revascularization than those without diabetes. Enhanced external counterpulsation has recently emerged as a treatment option for select patients with chronic stable angina.

METHODS

We examined baseline characteristics, angina response, and cardiac outcomes of patients with diabetes mellitus treated with Enhanced External Counterpulsation (EECP) for chronic stable angina. Data were collected from patients enrolled in the International EECP Patient Registry (IEPR) before and after a course of EECP, and at 1 year after completion of treatment.

RESULTS

Of 1532 IEPR patients studied, 43% had diabetes mellitus at baseline. Patients with diabetes were experiencing, on average, 11 episodes of angina per week. Most had been revascularized with prior percutaneous coronary intervention or coronary artery bypass graft surgery (86%) and most were considered unsuitable for either additional procedure (87%). Treatment was completed as prescribed in 79% of patients (mean, 32 hours). Immediately after EECP, 69% of patients with diabetes demonstrated a reduction in angina of > or =1 Canadian Cardiovascular Society angina class. After 1 year, maintenance of angina reduction was reported in 72% of patients with diabetes. Quality of life was significantly improved. Despite a high-risk profile among the diabetic group in this study, 1-year mortality was similar to coronary intervention registry populations.

CONCLUSION

This study suggests that in select patients with diabetes, EECP can be a safe, effective, well-tolerated treatment option for the relief of angina.

Angina 1 year after percutaneous coronary intervention: a report from the NHLBI Dynamic Registry

BACKGROUND

As percutaneous coronary intervention (PCI) is most commonly performed for relief of angina, it is important to identify factors associated with recurrence of anginal symptoms.

METHODS

We examined symptoms at 1-year follow-up in 1755 consecutive NHLBI Dynamic Registry patients who underwent PCI in the setting of symptoms or acute infarction.

RESULTS

At 1-year follow-up, 26% of patients reported angina in the previous 6 weeks. Younger patients and females reported more symptoms. History of coronary artery bypass graft (CABG) or PCI, prior myocardial infarction (MI), diabetes, graft disease, and extensive coronary artery disease (CAD) (>4 significant lesions) were also associated with follow-up angina. Patients receiving stents reported less angina (24% vs 29%, P <.05). Completely revascularized patients and those with residual single-vessel disease had comparable 1-year angina rates (23% both subgroups), while 32% of patients with residual multivessel CAD reported symptoms. Patients undergoing repeat PCI during follow-up reported more 1-year angina than others (34% vs 24%, P <.001), whereas those undergoing CABG after post-PCI hospitalization had less symptoms (15% vs 26%, P <.05). After adjustment for baseline symptom status and outcome of index PCI, residual CAD, and reintervention during follow-up, patient characteristics significantly predictive of angina included female sex, age <62 years, and prior MI.

CONCLUSIONS

While approximately three quarters of patients receiving PCI are angina-free at 1 year, females continue to have more symptoms, as do other subgroups including patients with history of MI or previous intervention. As these symptoms are associated with self-reported activity and quality of life limitation, evaluations of PCI should include angina as a key follow-up outcome.

Outcomes of patients with acute coronary syndromes and prior coronary artery bypass grafting: results from the platelet glycoprotein IIb/IIIa in unstable angina: receptor suppression using integrilin therapy (PURSUIT) trial

BACKGROUND

Patients with prior CABG with a subsequent non-ST-segment elevation acute coronary syndrome (ACS) pose an increasingly important clinical problem. Although GP IIb/IIIa inhibitors have improved the outcome of patients with ACS, their efficacy in patients with prior CABG has not been previously evaluated. Methods and Results- We analyzed the 30- and 180-day outcomes of patients with prior CABG enrolled in the Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Therapy (PURSUIT) trial. In this trial, which evaluated the efficacy of eptifibatide in patients with ACS, 1134 patients (12%) with prior CABG and 8321 without prior CABG were enrolled. After adjusting for differences in baseline characteristics and treatment, patients with prior CABG had a significantly higher mortality rates at 30 days (hazard ratio [HR], 1.45 [95% CI, 1.06 to 1.98]; P=0.019) and at 180 days (HR, 1.32 [95% CI, 1.04 to 1.67]; P=0.021). At 30 days, there was a similar effect on the primary end point of death or myocardial infarction in the eptifibatide group versus the placebo group in prior CABG patients (unadjusted HR, 0.90 [95% CI, 0.67 to 1.20]) and in patients without a history of CABG (unadjusted HR, 0.89 [95% CI, 0.80 to 0.99]).

CONCLUSIONS

Patients with prior CABG with non-ST-segment elevation ACS have a significantly worse prognosis than do patients without a history of CABG. The treatment effect of eptifibatide in the prior CABG group was similar to the effect seen in patients without prior CABG.

Long-term clinical outcome and predictors of major adverse cardiac events after percutaneous interventions on saphenous vein grafts

OBJECTIVES

The purpose of this study was to examine the long-term clinical outcome after percutaneous intervention of saphenous vein grafts (SVG) and to identify the predictors of major adverse cardiac events (MACE).

BACKGROUND

Percutaneous interventions of SVGs have been associated with more procedural complications and higher restenosis rates compared with interventions on native vessels.

METHODS

From 1993 to 1997, 1,062 patients underwent percutaneous intervention on 1,142 SVG lesions. Procedural, in-hospital and long-term clinical outcomes were recorded in a database and analyzed.

RESULTS

In-hospital MACE occurred in 137 patients (13%) including death (8%), Q-wave myocardial infarction (MI) (2%) and coronary artery bypass surgery (3%). Late MACE occurred in 565 patients (54%) including death (9%), Q-wave MI (9%) and target vessel revascularization (36%). Any MACE occurred in 457 (43%) patients. Follow-up was available in 1,056 (99%) patients at 3 +/- 1 year. Univariate predictors were restenotic lesion (odds ratio [OR]: 2.47, confidence interval [CI]: 1.13 to 3.85, p = 0.0003), unstable angina (OR: 1.99, CI: 1.27 to 2.91, p = 0.04) and congestive heart failure (CHF) (OR: 1.97, CI: 1.14 to 3.24, p = 0.02) for in-hospital MACE, and peripheral vascular disease (PVD) (OR: 2.18, CI: 1.34 to 3.44, p = 0.002), intra-aortic balloon pump placement (OR: 2.08, CI: 1.13 to 3.85, p = 0.02) and previous MI (OR: 1.97, CI: 1.14 to 3.25, p = 0.007) for late MACE. Independent multivariate predictors for late MACE were restenotic lesion (relative risk [RR] 1.33, p = 0.02), PVD (RR: 1.31, p = 0.01), CHF (RR: 1.42, p = 0.01) and multiple stents (RR: 1.47, p = 0.004). Angiographic follow-up was available for 422 patients. Angiographic restenosis occurred in 122 (29%) of stented SVGs and 181 (43%) of nonstented SVGs (p = 0.04). Stent implantation did not confer a survival benefit.

CONCLUSIONS

Despite the use of new interventional devices, SVG interventions are associated with significant morbidity and mortality; SVG stenting is not associated with better three-year event-free survival. This may be due to progressive disease at nonstented sites.

Direct coronary artery perfusion from the left ventricle

OBJECTIVES

Trends in coronary bypass surgery require less invasive techniques and more conduits. We investigated the ability of direct coronary perfusion from the left ventricle to support regional and global cardiac function.

METHODS

A conduit was established between the left ventricle and left anterior descending coronary artery (n = 6) with an interposed Starling resistor that allowed for graded regulation of backward flow. Changes of coronary flow, regional function in the territory of the left anterior descending coronary artery, and reactive hyperemia were studied. In 3 separate dogs, functional tolerance to increased heart rate was tested. In another 3 dogs, left ventricle-left anterior descending and left ventricle-left circumflex coronary artery conduits were established simultaneously (double conduit), and global function was tested.

RESULTS

Without flow regulation, flow through the left ventricle-left anterior descending conduit exhibited high peaking (102 +/- 35 mL/min), midsystolic forward flow, and large pandiastolic backward flow (peaking at -47 +/- 22 mL/min). Mean coronary flow and regional function were maintained at 46.0% +/- 7.1% (35.8%-54.2%) and 45.3% +/- 29.1% (-1.8%-74.2%) of their respective normal values. When the Starling resistor was used to regulate backward flow, these values increased to 70.8% +/- 12.5% (56.8%-90.4%) and 70.2% +/- 27.8% (23.6%-107.7%), respectively. Coronary and functional reserve with a left ventricle-left anterior descending conduit were not observed. With the double conduit, global ventricular contractility indexed by end-systolic pressure-volume relation averaged 46% +/- 35% of its normal value.

CONCLUSIONS

A left ventricle-coronary artery conduit supplied approximately 45% of normal blood flow and regional function, and both were improved by regulation of backward flow. Therefore, a conduit from the left ventricle to an epicardial vessel could serve as a rapidly deployable means of revascularizing totally occluded coronary vessels for which suitable natural conduits are not available.

The changing pattern of reoperative coronary surgery: trends in 1230 consecutive reoperations

OBJECTIVE

We noted an increasing risk profile of patients undergoing reoperative coronary surgery. We evaluated the risk compared with primary procedures, our results over a 16-year span, and the predictors of hospital outcomes after redo surgery.

METHODS

We analyzed 20,614 patients undergoing isolated coronary surgery at our institution from 1982 to 1997. Of these, 1230 (6.0%) were undergoing reoperation. Independent predictors of outcomes were identified by multivariable regression.

RESULTS

The prevalence of reoperation peaked in 1994 at 8.2%. Patients undergoing reoperation were more likely to be male, to have left ventricular dysfunction and worse symptoms, and to require an urgent operation than patients undergoing a primary operation (P <.0001). Perioperative myocardial infarctions (3.7% vs 7.4%), low-output syndrome (9.0% vs 24.0%), and death (2.4% vs 6.8%) were more common in patients undergoing reoperation (all P <.0001). Over the years, the risk profile of patients undergoing reoperation increased. Age, left ventricular dysfunction, severity of symptoms, extent of coronary artery disease, left main stenosis, and requirement for urgent or emergency operations increased with time (P <.05). However, mortality, myocardial infarction, and low-output syndrome have remained constant. The independent predictors of mortality after reoperative surgery were increased age, greater Canadian Cardiovascular Society symptom class, earlier year of operation, and greater left ventricular dysfunction. After 1990, analysis of an expanded data set also identified peripheral vascular disease and failure to use retrograde cardioplegia as predictors of mortality.

CONCLUSIONS

Improving results of reoperative surgery have been offset by an increasing patient risk profile. Meticulous operative technique and retrograde cardioplegia may permit good results in these high-risk patients.

Functional assessment of disease-free saphenous vein grafts at redo coronary artery bypass grafting

BACKGROUND

Reoperations for coronary artery bypass grafting are on the rise. The general rule of replacing all saphenous vein grafts (SVGs) older than 5 years of age at the time of reoperation has recently been challenged on clinical grounds. This study provides functional data of endothelial behavior in long-term vein grafts.

METHODS

Previously placed SVGs were removed at the time of redo operations. Nitric oxide (NO) measurements in real time were carried out before and after stimulation with morphine. The measurements were compared to the angiographic appearance of the grafts obtained prior to operation. Grafts were categorized into 3 groups: disease-free, moderately diseased, and severely diseased.

RESULTS

Sixteen grafts were analyzed. Five were angiographically disease-free, 4 had moderate, and 7 severe disease. In the disease-free group, peak NO production after 10(-6) mol/L morphine stimulation was 35 mol/L, equivalent to the production of native saphenous vein. The severely diseased group did not demonstrate an increase in NO production, and the moderately diseased group produced a small rise in production.

CONCLUSIONS

Measurement of NO release of old SVGs, when angiographically pristine, equals that of native saphenous vein. These findings support the recent clinical observations that long-term angiographically disease-free vein grafts are biologically privileged.

Percutaneous coronary interventions in patients with prior coronary artery bypass surgery: changes in patient characteristics and outcome during two decades

PURPOSE

Patients who develop recurrent myocardial ischemia after coronary artery bypass graft (CABG) surgery are often referred for percutaneous coronary interventions. The objective of this study was to evaluate the changing demographic and clinical characteristics, and procedural and long-term outcomes, in patients with prior CABG referred for percutaneous coronary interventions during a 20-year period.

METHODS

We prospectively collected data on patients who underwent coronary interventional procedures following CABG surgery. We compared angiographic and procedural success, and long-term event-free survival, among patients who had procedures from 1979 to 1989 (n = 393), from 1990 to 1994 (n = 811), and from 1995 to 1998 (n = 937).

RESULTS

Patients in the 1995 to 1998 cohort were older, had a lower mean left ventricular ejection fraction, and were more likely to have diabetes, hypertension, and hyperlipidemia, but less likely to smoke. They were more likely to have treatment of complex lesions, including vein graft lesions, and had more prior CABG surgeries. More patients received intracoronary stents in 1995 to 1998. Both angiographic success rates (78% from 1979 to 1989, 88% from 1990 to 1994, and 91% from 1995 to 1998, P < 0.0001) and procedural success rates (78%, 86%, and 91%, P < 0.0001) improved with time. Long-term mortality was greater in the pre-1990 group (relative risk = 1.8, 95% confidence interval: 1.3 to 2.4) and 1990 to 1994 group (relative risk = 1.7, 95% confidence interval: 1.3 to 2.2) compared with the 1995 to 1998 group, as were the likelihoods of repeat revascularization and recurrent severe angina.

CONCLUSION

Although the demographic and clinical characteristics of patients who underwent percutaneous intervention following CABG surgery indicate that they are at increasingly greater risk of adverse cardiac events, success rates and long-term survival have improved with time. The rates of recurrent severe angina as well as of subsequent revascularization have also decreased, probably as a result of improvements in technique and greater use of stents and adjunctive medications.

Long-term follow-up after coronary artery bypass grafting reoperation

BACKGROUND

Coronary artery bypass grafting (CABG) reoperation is being performed with increasing frequency.

OBJECTIVE

To determine the clinical outcome and the long-term results of a second CABG.

SETTING

An 1100-bed urban university-affiliated hospital.

DESIGN

Retrieval of data on selected parameters from medical records before surgery and prospective follow-up afterwards.

PATIENTS AND METHODS

We studied the outcomes of 498 consecutive patients who underwent CABG reoperation in our institution from January 1978 to December 1989 and who were followed postoperatively. Their perioperative mortality, morbidity, and long-term follow-up results were re-evaluated. The end points of the study were December 1997, 15 years of follow-up, or the patient's death.

RESULTS

The perioperative mortality rate was 3%. The cumulative survival rates were 90.1%, 74%, and 63.4% at the 5-year, 10-year, and 15-year follow-ups, respectively. The cardiac event-free survival rates were 91.5%, 83.4%, and 67.8% at the 5-year, 10-year, and 15-year follow-ups, respectively. The risk factors adversely affecting long-term survival were advanced age, hypertension, and a low left ventricular ejection fraction (LVEF).

CONCLUSIONS

The long-term results of cumulative survival and cardiac event-free survival in patients who underwent CABG reoperation are good. Although this reoperation is safe overall, advanced age, hypertension, and a decreased LVEF significantly increase the surgical risk.

Perioperative cardiovascular morbidity in patients with coronary artery disease undergoing vascular surgery after percutaneous transluminal coronary angioplasty

OBJECTIVE

Patients with coronary artery disease (CAD) who undergo noncardiac surgery are at increased risk for perioperative myocardial infarction (PMI). Undergoing successful coronary artery bypass grafting (CABG) before such surgery has been shown to decrease perioperative cardiac morbidity and mortality. Percutaneous transluminal coronary angioplasty (PTCA) is an alternative treatment for these patients. Perioperative cardiac morbidity in patients with CAD who underwent PTCA before their vascular surgery was reviewed.

SETTING

A tertiary care referral center for patients with cardiovascular heart disease.

PARTICIPANTS

Review of vascular surgery database for patients who underwent vascular surgery preceded by PTCA between 1984 and 1995. Patients were excluded if they had a history of CABG within 2 years of surgery, had PTCA more than 18 months before surgery, or had incomplete data.

MEASUREMENTS

Data were collected concerning cardiac history, left ventricular (LV) function, perioperative cardiac morbidity (angina, MI, congestive heart failure [CHF], and arrhythmias).

MAIN RESULTS

Of 194 patients who underwent aortic abdominal surgery, carotid endarterectomy (CEA), or peripheral vascular surgery preceded by PTCA, 104 (54%) had a previous MI. Twenty-six patients (13.4%) had perioperative cardiac morbidity. Only one patient had an MI (0.5%; 95% confidence interval [CI], 0.0 to 2.8), whereas one patient died of CHF followed by multisystem organ failure (0.5%). The median interval between PTCA and surgery was 11 days (interquartile range, [IQR] 3 to 49 days). Patients who developed perioperative cardiac morbidity were older than those who did not (p = 0.02). Patients who had a history of CABG (before PTCA) had a higher incidence of postoperative angina (p = 0.04). The degree of preoperative LV dysfunction was linearly related to the incidence of new postoperative CHF (p = 0.01). Arrhythmias were more common in patients undergoing abdominal vascular surgery (17.9%) than in those undergoing CEA (2.5%; p = 0.03) or peripheral vascular surgery (5.2%; p = 0.02).

CONCLUSION

High-risk cardiac patients undergoing vascular surgery who have had PTCA performed up to 18 months preoperatively have a low incidence of perioperative cardiac morbidity. Prophylactic PTCA may be beneficial in patients with CAD who are at high risk for perioperative cardiac complications.