Does the completeness of revascularization affect early survival after coronary artery bypass grafting in elderly patients?

Outcomes of quantitative flow ratio-based functional incomplete revascularization after coronary artery bypass grafting surgery

OBJECTIVE

Quantitative flow ratio is a novel functional assessment tool of coronary diseases. Whether quantitative flow ratio could improve the outcomes of coronary artery bypass grafting is undetermined. This study aimed to investigate the association between the quantitative flow ratio based functional incomplete revascularization and the outcomes after coronary artery bypass grafting surgery.

METHODS

The quantitative flow ratio assessment was retrospectively performed in patients undergoing coronary artery bypass grafting surgery in the PATENCY trial. The anatomic complete revascularization denoted revascularizing each territory with stenosis greater than 50% evaluated by angiography. The functional complete revascularization was defined as grafting all vessels with a quantitative flow ratio 0.80 or less. The primary end point was the 12-month composite major adverse cardiac or cerebral vascular events.

RESULTS

A total of 2024 patients with available quantitative flow ratio values were included. Functional complete revascularization was achieved in 1846 patients (91.2%), and 1600 received anatomic complete revascularization (79.1%). Both the functional incomplete revascularization and anatomic incomplete revascularization groups were associated with significantly increased risks of 12-month major adverse cardiac or cerebral vascular events (functional: hazard ratio, 2.91; 95% confidence interval, 1.56 to 5.43; P = .001; anatomic: hazard ratio, 2.82; 95% confidence interval, 1.54 to 5.16; P = .001). Additionally, for the subgroup of patients (n = 246) receiving anatomic incomplete revascularization but judged as functional complete revascularization by quantitative flow ratio, the risk of the 12-month major adverse cardiac or cerebral vascular events was not significantly increased (adjusted hazard ratio, 1.36; 95% confidence interval, 0.71-2.60; P = .35).

CONCLUSIONS

Both the functional incomplete revascularization and anatomic incomplete revascularization were associated with increased risks of 12-month major adverse cardiac or cerebral vascular events after coronary artery bypass grafting surgery. The quantitative flow ratio can serve as a supplementary tool for the decision-making of surgical revascularization.

Synergistic Effect of Transmyocardial Revascularization and Platelet-Rich Plasma on Improving Cardiac Function After Coronary Artery Bypass Grafting

Background Coronary artery disease (CAD) is a global health burden, contributing to mortality and morbidity. A proportion of patients with CAD suffer from diffuse CAD, where conventional revascularization techniques such as percutaneous coronary intervention and coronary artery bypass grafting (CABG) may be insufficient to adequately restore myocardial perfusion. Transmyocardial revascularization (TMR) uses a laser to create microscopic channels in the myocardium, inducing inflammation, angiogenesis, and neovascularization to improve perfusion to ischemic regions. Platelet-rich plasma (PRP) is an autologous concentrate of platelets that contains a myriad of growth factors and bioactive proteins, which have been shown to promote tissue regeneration and wound healing. The combination of TMR and PRP therapies has been proposed to synergistically enhance myocardial revascularization and functional recovery in patients with advanced CAD undergoing surgical revascularization. Methods This study evaluated the efficacy of combining TMR and PRP with CABG in improving cardiac function in diffuse CAD patients. Fifty-two patients were randomized to CABG alone (n = 16), CABG+TMR (n = 17), CABG+PRP (n = 10), and CABG+TMR+PRP (n = 9). TMR was performed using a holmium:YAG laser to create 10 channels in the inferolateral left ventricular wall. PRP was prepared from autologous whole blood and injected into the myocardium adjacent to the TMR channels. Cardiac function was assessed using speckle-tracking echocardiography preoperatively, postoperatively, and at one-year follow-up. Adverse events, including post-operative atrial fibrillation, acute kidney injury, and readmissions, were also recorded. Statistical analyses were performed to compare outcomes between the treatment groups. Results The CABG+TMR+PRP group showed significantly improved global longitudinal strain (GLS) at one year compared to CABG alone (mean GLS -15.96 vs -12.09, p = 0.02). Post-operative left ventricular ejection fraction trended higher in the TMR+PRP group (57.78%) vs other groups, but not significantly. Post-operative atrial fibrillation was higher in the TMR+PRP group (67% vs 25%, p = 0.04), potentially reflecting increased inflammation. No significant differences were observed in other adverse events. Conclusions The results of this study suggest a synergistic benefit of combining TMR and PRP therapies as an adjunct to CABG in patients with diffuse CAD. The significant improvement in GLS at one year in the TMR+PRP group compared to CABG alone indicates enhanced myocardial remodeling and functional recovery, which may translate to improved long-term outcomes. The higher incidence of postoperative atrial fibrillation in the TMR+PRP group warrants further investigation but may reflect the heightened inflammatory response necessary for angiogenesis and tissue regeneration. Prospective, randomized controlled trials with larger sample sizes and longer follow-up periods are needed to validate these findings and optimize treatment protocols. Nonetheless, concomitant TMR+PRP therapy represents a promising approach to augmenting myocardial revascularization and recovery in patients with advanced CAD undergoing surgical revascularization.

Calcium Modification Therapies in Contemporary Percutaneous Coronary Intervention

Coronary Artery Calcification (CAC) has been known to be associated with worse Percutaneous Coronary Intervention (PCI) short- and long-term outcomes. Nowadays, with the increased prevalence of the risk factors leading to CAC in the population and also more PCI procedures done in older patients and with the growing number of higher-risk cases of Chronic Total Occlusion (CTO) PCI and PCI after Coronary Artery Bypass Grafting (CABG), severe cases of CAC are now encountered on a daily basis in the catheterization lab and remain a big challenge to the interventional community, making it crucial to identify cases of severe CAC and plan a CAC PCI modification strategy upfront. Improved CAC detection with intravascular imaging helped identify more of these severe CAC cases and predict response to therapy and stent expansion based on CAC distribution in the vessel. Multiple available therapies for CAC modification have evolved over the years. Familiarity with the specifics and special considerations and limitations of each of these tools are essential in the choice and application of these therapies when used in severe CAC treatment. In this review, we discuss CAC pathophysiology, modes of detection, and different available therapies for CAC modification.

Complete revascularization during coronary artery bypass grafting is associated with reduced major adverse events

OBJECTIVE

Complete revascularization literature is limited by variance in patient cohorts and inconsistent definitions. The objective of the current study was to provide risk-adjusted outcomes for complete revascularization of significant nonmain-branch and main-branch vessel stenoses.

METHODS

All patients that underwent first-time isolated coronary artery bypass grafting procedures were included. Kaplan-Meier survival estimates, cumulative incidence function, and Cox regression were used to analyze outcomes.

RESULTS

The total population consisted of 3356 patients that underwent first-time isolated coronary artery bypass grafting. Eight hundred eighty-nine (26.5%) patients had incomplete and 2467 (73.5%) had complete revascularization. For main-branch vessels, 677 (20.2%) patients had incomplete revascularization and 2679 (79.8%) were completely revascularized. Following risk adjustment with inverse probability treatment weighting, all baseline characteristics were balanced (standardized mean difference, ≤ 0.10). On Kaplan-Meier estimates, survival at 1 year (94.6% vs 92.5%) and 5 years (86.5% vs 82.1%) (P = .05) was significantly better for patients who received complete revascularization. Freedom from major adverse cardiac and cerebrovascular events was significantly higher for the complete revascularization cohort at both 1 year (89.2% vs 84.2%) and 5 years (72.5% vs 66.7%) (P < .001). Complete revascularization (hazard ratio, 0.82; 95% confidence interval, 0.70-0.95; P = .01) was independently associated with a significant reduction in major adverse cardiac and cerebrovascular events. Incomplete revascularization of nonmain-branch vessels was not associated with mortality (hazard ratio, 1.14; 95% confidence interval, 0.74-1.8; P = .55) or major adverse cardiac and cerebrovascular events (hazard ratio, 0.90; 95% confidence interval, 0.66-1.24; P = .52).

CONCLUSIONS

Complete surgical revascularization of all angiographically stenotic vessels in patients with multivessel coronary artery disease is associated with fewer major adverse events. Incomplete revascularization of nonmain-branch vessels is not associated with survival or major adverse cardiac and cerebrovascular events.

Transmyocardial revascularization (TMR): current status and future directions

Purpose

Cardiac surgeons are increasingly faced with a more complex patient who has developed a pattern of diffuse coronary artery disease (CAD), which is refractory to medical, percutaneous, and surgical interventions. This paper will review the clinical science surrounding transmyocardial revascularization (TMR) with an emphasis on the results from randomized controlled trials.

Methods

Randomized controlled trials which evaluated TMR used as sole therapy and when combined with coronary artery bypass grafting were reviewed. Pertinent basic science papers exploring TMR's possible mechanism of action along with future directions, including the synergism between TMR and cell-based therapies were reviewed.

Results

Two laser-based systems have been approved by the United States Food and Drug Administration (FDA) to deliver laser therapy to targeted areas of the left ventricle (LV) that cannot be revascularized using conventional methods: the holmium:yttrium-aluminum-garnet (Ho:YAG) laser system (CryoLife, Inc., Kennesaw, GA) and the carbon dioxide (CO₂) Heart Laser System (Novadaq Technologies Inc., (Mississauga, Canada). TMR can be performed either as a stand-alone procedure (sole therapy) or in conjunction with coronary artery bypass graft (CABG) surgery in patients who would be incompletely revascularized by CABG alone. Societal practice guidelines have been established and are supportive of using TMR in the difficult population of patients with diffuse CAD.

Conclusions

Patients with diffuse CAD have increased operative and long-term cardiac risks predicted by incomplete revascularization. The documented operative and long-term benefits associated with sole therapy and adjunctive TMR in randomized trials supports TMR's increased use in this difficult patient population.

Survival outcomes post percutaneous coronary intervention: Why the hype about stent type? Lessons from a healthcare system in India

A prospective, multicenter study was initiated by the Government of Maharashtra, India, to determine predictors of long-term outcomes of percutaneous coronary intervention (PCI) for coronary artery disease, and to compare the effectiveness of drug-eluting stents (DESs) and bare-metal stents (BMSs) in patients undergoing PCI under government-funded insurance. The present analysis included 4595 patients managed between August 2012 and November 2016 at any of 110 participating centers. Using the classical multivariable regression and propensity-matching approach, we found age to be the most important predictor of 1-year mortality and target lesion revascularization at 1 year post-PCI. However, using machine learning methods to account for unmeasured confounders and bias in this large observational study, we determined total stent length and number of stents deployed as the most important predictors of 1-year survival, followed by age and employment status. The unadjusted death rates were 5.0% and 3.8% for the BMS and DES groups, respectively (p = 0.185, log-rank test). The rate of re-hospitalization (p<0.001) and recurrence of unstable angina (p = 0.08) was significantly lower for DESs than for BMSs. Increased use of DES after 2015 (following establishment of a price cap on DESs) was associated with a sharp decrease in adjusted hazard ratios of DESs versus BMSs (from 0.94 in 2013 to 0.58 in 2016), suggesting that high price was limiting DES use in some high-risk patients. Since stented length and stent number were the most important predictors of survival outcomes, adopting an ischemia-guided revascularization strategy is expected to help improve outcomes and reduce procedural costs. In the elderly, PCI should be reserved for cases where the benefits outweigh the higher risk of the procedure. As unemployed patients had poorer long-term outcomes, we expect that implementation of a post-PCI cardiovascular rehabilitation program may improve long-term outcomes.

Residual SYNTAX score following coronary artery bypass grafting

Objectives

To quantify residual coronary artery disease measured using the SYNTAX score (SS) and its relation to outcomes after coronary artery bypass grafting (CABG).

Methods

We conducted a retrospective analysis on a consecutive series of 1608 patients [mean age 68 years, standard deviation (SD): 7, F:M, 242:1366] undergoing first-time isolated CABG from 2004 to 2015. The baseline SS was retrospectively determined from preoperative angiograms, and the residual SS (rSS) was measured during assessment of the actual operative report for each patient after CABG. Patients were then stratified according to tercile cut points of low (rSS low 0-11, N  = 537), intermediate (rSS mid  >11-18.5, N  = 539) and high residual SS (rSS high  >18.5, N  = 532). The Cox regression model was used to investigate the impact of rSS on major adverse cardiac and cerebrovascular events (MACCE) at 1 year.

Results

The mean preoperative SS was 26.6 (SD: 9.4) (range 10.1-53), and the residual SS after CABG was 15.3 (SD: 8.4) (range 0-34) ( P  <   0.001 versus preoperative). At 1 year, cumulative incidence of MACCE in the low rSS was 1.5% ( N  = 8/537), 4.5% ( N  = 24/539) in the intermediate and 8.8% ( N  = 47/532) in the high rSS group. Kaplan-Meier analysis showed a statistically significant difference of MACCE-free survival between the three groups (log-rank test, P  <   0.001). The estimated MACCE-free survival rate at 1 year was 98.1% [standard error (SE): 1.6] for the rSS low , 95.5% (SE: 1.9) for the rSS mid , and 90.5% (SE: 1.3) for the rSS high group, respectively. After multivariable adjustment, the rSS high group was independently associated with a higher incidence of MACCE at 1 year (hazard ratio 1.92, 95% confidence interval 1.21-3.23) compared to the rSS low group.

Conclusions

These unanticipated findings suggest that a residual SS may be a useful tool for risk stratification of patients undergoing isolated first-time CABG. Our study may set the stage for further investigations addressing this important clinical question.

Right-sided reverse T composite arterial grafting to complete revascularization of the right coronary artery

Complete arterial revascularization for the right coronary artery is underused mainly due to technical issues. Herein we report on a new approach for complete arterial revascularization of arterial revascularization for the right coronary artery branches. Complete arterial revascularization for the right coronary artery revascularization was performed in 8 patients using a reverse T composite arterial graft. None of the patients suffered perioperative myocardial infarction. All patients underwent noninvasive coronary imaging, displaying an early patency rate of 100%. Complete arterial arterial revascularization for the right coronary artery revascularization using a reverse T graft offers a new paradigm with enhanced technical flexibility in performing all arterial myocardial complete revascularizations in selected patients.

Transmyocardial revascularization devices: technology update

Transmyocardial laser revascularization (TMR) emerged as treatment modality for patients with diffuse coronary artery disease not amendable to percutaneous or surgical revascularization. The procedure entails the creation of laser channels within ischemic myocardium in an effort to better perfuse these areas. Currently, two laser devices are approved by the US Food and Drug Administration for TMR – holmium:yttrium–aluminum–garnet and CO₂. The two devices differ in regard to energy outputs, wavelengths, ability to synchronize with the heart cycle, and laser–tissue interactions. These differences have led to studies showing different efficacies between the two laser devices. Over 50,000 procedures have been performed worldwide using TMR. Improvements in angina stages, quality of life, and perfusion of the myocardium have been demonstrated with TMR. Although several mechanisms for these improvements have been suggested, evidence points to new blood vessel formation, or angiogenesis, within the treated myocardium, as the major contributory factor. TMR has been used as sole therapy and in combination with coronary artery bypass grafting. Clinical studies have demonstrated that TMR is both safe and effective in angina relief long term. The objective of this review is to present the two approved laser devices and evidence for the safety and efficacy of TMR, along with future directions with this technology.

Holmium:YAG laser system for transmyocardial revascularization

Transmyocardial revascularization, using the US FDA-approved holmium: yttrium-aluminum-garnet (Ho:YAG) laser system, is a surgical option for patients with debilitating angina caused by diffuse coronary artery disease in areas of the heart not amenable to complete revascularization using conventional treatments. Increased utilization of this therapy is warranted, in parallel with continuing research into therapeutic or cell-based methods for enhancing the clinically relevant, positive outcomes. This article will review the clinical science surrounding Ho:YAG transmyocardial revascularization with an emphasis on the randomized controlled trials performed in these patient groups.

Detection of gender differences in incomplete revascularization after coronary artery bypass surgery varies with classification technique

Background. Incomplete revascularization negatively affects survival after coronary artery bypass surgery (CABG). Since gender and classification technique might impact outcome and reporting, we investigated their effect on revascularization patterns and mortality. Methods. A cohort of bypass patients (N = 1545, 23% women) was enrolled prospectively. The degree of revascularization was determined as mathematical difference between affected vessels upon diagnosis and number of grafts or the surgeon's rating on the case file. Results. Although men displayed more triple-vessel disease, they obtained complete revascularization more frequently than women (85% versus 77%, P < 0.001). The two calculation methods identified analogous percentages of incompletely revascularized patients, yet there was only a 50% overlap between the two groups. Mathematically, more women, older patients, and patients with NYHA class III/IV appeared incompletely revascularized, while the surgeons identified more patients undergoing technically challenging procedures. Regardless of the definition, incompleteness was a significant risk factor for mortality in both genders (mathematical calculation: HR 2.62, 95% CI 1.76–3.89, P < 0.001; surgeon: HR 2.04, 95% CI 1.35–3.89, P = 0.001). Conclusions. Given the differences in identification patterns, we advise that the mathematical calculation be performed after-procedure in all patients regardless of the surgeons' rating to uncover additional subjects at increased risk.

Impact of incomplete revascularization in patients undergoing PCI for unprotected left main stem stenosis

INTRODUCTION

Percutaneous revascularization of patients with multivessel and left main stem (LMS) disease may be incomplete and the impact of this is not well reported and may influence outcome. In this study we assessed the role of completeness of revascularization upon outcome after PCI for unprotected left main stem (uLMS) PCI in the "real world."

MATERIALS AND METHOD

Consecutive patients (n = 353) with uLMS disease were treated by PCI by a single operator with a policy of maximal feasible revascularization between 2000 and 2011. The SYNTAX score was calculated before and after PCI (residual SYNTAX score) to gauge the completeness of revascularization. The endpoints were mortality and repeat revascularization.

RESULTS

Mean age was 69 ± 11 years, baseline SYNTAX score was 33.4 ± 15, 53% were nonelective, 10% were in cardiogenic shock, and 45% were not surgical candidates. LMS bifurcation was involved in 74% and 2.0 ± 0.9 other vessels were diseased. Complete revascularization was achieved in 49% and was associated with reduced mortality compared with incomplete, at 30 days [5(2.9%) v 23(13%)], 1 year [9(5%) v 34(19%)], and 3 years [14(8%) v 46(26%)]; all P < 0.0001). Median rSYNTAX score was 1(0-11), 1-year survival for the lowest, middle and highest tertiles of rSYNTAX were 1.7%, 3.1% and 7.3% (P < 0.0001), respectively. In multivariate analysis postprocedure rSYNTAX score independently predicted outcome but preprocedural SYNTAX score did not.

CONCLUSIONS

For unselected patients with uLMS treated by PCI, completeness of revascularization is associated with superior survival. The rSYNTAX score, a novel index of completeness of revascularization, independently predicts survival. Baseline SYNTAX score does not.

Complete revascularization is compromised in off-pump coronary artery bypass grafting

OBJECTIVE

Patients who undergo off-pump coronary artery bypass grafting (OPCAB) commonly receive fewer bypass grafts and are more often incompletely revascularized compared with those receiving conventional coronary artery bypass (CCAB) recipients. Because this can compromise survival, we sought to determine whether patients undergoing OPCAB are incompletely revascularized and whether this affects long-term survival and freedom from cardiac events.

METHODS

OPCAB cases (n = 411) performed from January 1, 1997 to June 30, 2003 were considered for inclusion and matching with 874 randomly selected, contemporary CCAB cases. After propensity matching, 308 OPCAB cases and 308 CCAB cases were included in the final analysis. We compared the number of bypass grafts and the completeness of revascularization by coronary territory. Survival and readmission for cardiac causes were monitored for up to 10 years postoperatively, with a median follow-up period of 5.9 years.

RESULTS

On average, the patients undergoing OPCAB received significantly fewer distal anastomoses than did those undergoing CCAB (mean ± standard deviation, 2.6 ± 0.9 vs 3.0 ± 1.0, P < .0001). The circumflex territory was the most likely territory to be ungrafted during OPCAB in patients with angiographically significant obstruction (P = .0006). The frequency of complete revascularization was significantly different between the 2 groups (OPCAB, 79.2% vs CCAB, 88.3%; P = .0.002). The OPCAB group had a significantly greater rate of total arterial grafting (OPCAB, 66.6% vs CCAB, 49.7%; P = .0001). No difference was seen in 8-year survival or freedom from cardiac cause hospital readmission between the 2 groups.

CONCLUSIONS

Despite receiving fewer distal anastomoses and the decreased frequency of complete revascularization, OPCAB and CCAB techniques produced comparable results.

Incidence, predictors and outcomes of incomplete revascularization after percutaneous coronary intervention and coronary artery bypass grafting: a subgroup analysis of 3-year SYNTAX data

OBJECTIVE

To assess whether incomplete revascularization by percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) has an effect on long-term outcomes.

METHODS

During a heart team discussion to evaluate whether patients were eligible for randomization in the SYNTAX trial, both the cardiologist and surgeon agreed on which vessels needed revascularization. This statement was compared with the actual revascularization after treatment. Incomplete revascularization was defined as when a preoperatively identified vessel with a lesion was not revascularized. Outcomes were major adverse cardiac or cerebrovascular events (MACCE), the composite safety endpoint of death/stroke/myocardial infarction (MI), and individual MACCE components death, MI and repeat revascularization at 3 years. Predictors of incomplete revascularization were explored.

RESULTS

Incomplete revascularization was found in 43.3% (388/896) PCI and 36.8% (320/870) CABG patients. Patients with complete revascularization by PCI had lower rates of MACCE (66.5 versus 76.2%, P < 0.001), the composite safety endpoint (83.4 versus 87.9%, P = 0.05) and repeat revascularization (75.5 versus 83.9%, P < 0.001), but not death and MI. In the CABG group, no difference in outcomes was seen between incomplete and complete revascularization groups. Incomplete revascularization was identified as independent predictor of MACCE in PCI (HR = 1.55, 95% CI 1.15-2.08, P = 0.004) but not CABG patients. Independent predictors of incomplete revascularization by PCI were hyperlipidaemia (OR = 1.59, 95% CI 1.04-2.42, P = 0.031), a total occlusion (OR = 2.46, 95% CI 1.66-3.64, P < 0.001) and the number of vessels (OR = 1.58, 95% CI 1.41-1.77, P < 0.001). Independent predictors of incomplete revascularization by CABG were unstable angina (OR = 1.42, 95% CI 1.02-1.98, P = 0.038), diffuse disease or narrowed ( < 2 mm) segment distal to the lesion (OR = 1.87, 95% CI 1.31-2.69, P = 0.001) and the number of vessels (OR = 1.70, 95% CI 1.53-1.89, P < 0.001).

CONCLUSIONS

Despite the hypothesis-generating nature of this data, this study demonstrates that incomplete revascularization is associated with adverse events during follow-up after PCI but not CABG.

Off-pump coronary artery bypass may increase late mortality: a meta-analysis of randomized trials

BACKGROUND

Although a lot of randomized trials of off-pump coronary artery bypass grafting (CABG) versus on-pump CABG were conducted, the majority of them reported only early outcomes. Previous meta-analyses of a few randomized trials found no differences for 1-year to 2-year mortality.

METHODS

We focused late (> or = 1 year) all-cause mortality and performed a meta-analysis of randomized controlled trials of off-pump versus on-pump CABG. The MEDLINE, the EMBASE, and the Cochrane Central Register of Controlled Trials were searched using PubMed and OVID. For each study, data regarding all-cause mortality in both the off-pump and on-pump groups were used to generate risk ratios (RRs) and 95% confidence intervals. Study-specific estimates were combined using inverse variance-weighted averages of logarithmic RRs in both fixed-effects and random-effects models.

RESULTS

Our search identified 11 results of 12 randomized trials (4,326 patients) of off-pump versus on-pump CABG. Pooled analysis demonstrated a statistically significant increase in midterm all-cause mortality by a factor of 1.37 with off-pump relative to on-pump CABG (RR, 1.373; 95% confidence interval, 1.043 to 1.808). Exclusion of any single result, except for the largest (>2,000 patients) trial, from the analysis did not substantively alter the overall result of our analysis. Eliminating the largest trial demonstrated a statistically nonsignificant benefit of on-pump over off-pump CABG for midterm all-cause mortality (RR, 1.344; 95% confidence interval, 0.952 to 1.896).

CONCLUSIONS

The results of our analysis suggest that off-pump CABG may increase late all-cause mortality by a factor of 1.37 over on-pump CABG. Longer term mortality from randomized trials of off-pump versus on-pump CABG is needed.

Remote ischemic preconditioning reduces myocardial injury after coronary artery bypass surgery with crystalloid cardioplegic arrest

Remote ischemic preconditioning (RIPC) with transient upper limb ischemia reduces myocardial injury in patients undergoing on-pump coronary artery bypass grafting (CABG) with cross-clamp fibrillation or blood cardioplegia for myocardial protection. Whether or not such protection is still operative when standard crystalloid cardioplegic arrest is used is uncertain. Fifty-three consecutive, non-diabetic patients with triple-vessel disease and 64 +/- 12 years of age (mean +/- SD), who underwent elective CABG surgery with crystalloid (Bretschneider) cardioplegic arrest, were allocated in a prospective, randomized, single-blinded protocol to receive either a RIPC protocol (3 cycles of 5 min transient left upper arm ischemia induced by inflating a blood pressure cuff to 200 mmHg with 5 min of reperfusion) or control, respectively, after induction of anesthesia. Cardiac troponin I (cTnI) concentration was measured preoperatively and over 72 h postoperatively, and the area under the curve (AUC) was calculated. Peak postoperative cTnI concentration was significantly reduced from 13.7 +/- 7.7 ng/mL in controls to 8.9 +/- 4.4 ng/mL in RIPC (P = 0.008). Mean cTnI concentration was significantly lower at 6, 12, 24, and 48 h after surgery (ANOVA; P < 0.0001) in the RIPC patients (N = 27) than in controls (N = 26), resulting in a 44.5% reduction of cTnI (AUC at 72 h). RIPC by repetitive inflation of a cuff around the left upper arm before surgery enhances myocardial protection in patients undergoing CABG surgery with antegrade cold crystalloid cardioplegia.

Long-Term Outcomes After CABG With Concomitant CO2 Transmyocardial Revascularization in Comparison With CABG Alone

OBJECTIVES

: Transmyocardial revascularization (TMR) has been used as an isolated or adjunctive revascularization therapy in patients presumed to have nonbypassable coronary artery disease. The purpose of this study is to evaluate the short- and midterm mortality for patients with complete revascularization using TMR and coronary artery bypass grafting (CABG) compared with those patients with incomplete CABG revascularization and to document long-term follow-up in patients receiving TMR + CABG.

METHODS

: Seventy TMR + CABG patients were cohort matched with 70 patients undergoing isolated CABG with circumflex coronary artery disease, but with no bypassable distal targets, from 1999 to 2005 at Emory University Hospital. The data were retrospectively reviewed from a database after being prospectively entered. Results are presented in mean ± standard deviation, and Kaplan-Meier curves were created for long-term all-cause mortality.

RESULTS

: The TMR + CABG patients had a similar incidences to the CABG only group for preoperative ejection fraction (50.9 ± 11.2% vs. 50.7 ± 10.3%, P = 0.93), number of grafts (2.6 ± 1.1 vs. 2.5 ± 1.3, P = 0.5), and number of diseased vessels (2.8 ± 0.3 vs. 2.9 ± 0.4, P = 0.26). Off-pump surgery was used more often in the CABG alone group versus the TMR combined with CABG group (74.3% vs. 41.4%, P < 0.001). Postoperatively, there was no statistical difference among the TMR + CABG and the CABG alone groups for intensive care unit length of stay (4.3 ± 7.8 days vs. 2.6 ± 3.4 days, P = 0.026), postsurgical length of stay (7.6 ± 6.1 days vs. 6.8 ± 4.5 days, P = 0.31), stroke events (1.4% vs. 1.4%, P = 1.00), myocardial infarction (4.3% vs. 2.9%, P = 0.65), and 30-day mortality (5.7% vs. 4.3%, P = 0.70). Long-term survival rate was not statistically significant. In addition, 4-year follow-up in the TMR + CABG group had symptom improvement with reduction in New York Heart Association classification for class III/IV (P < 0.0001, baseline vs. 4-year follow-up).

CONCLUSIONS

: The combination of TMR and CABG for complete revascularization is safe and carries no further risk to patients compared with CABG only. CABG + TMR patients tend to have increased resource utilization. Long-term follow-up shows similar survival between the groups. TMR can be a useful adjunct to CABG for complete revascularization.

[Minimally invasive heart and mitral valve surgery]

During the last decades, minimally invasive operative techniques have been established in various subspecialties of modern cardiac surgery, offering now safe and efficient alternative treatment options for most of the patients. Those new and innovative options thereby aimed to reduce the operative trauma and perioperative morbidity, and furthermore, to increase patients' satisfaction and optimize patients' security. After continuous enhancement of these minimally invasive techniques during the last 10 years, numerous current reports demonstrate minimally invasive cardiac surgery techniques to be safe and efficient, resulting in equal or even better mortality and morbidity compared to conventional cardiac surgery. The underlying benefits of minimally invasive cardiac surgery are characterized by shorter hospital stay, less postoperative pain, accelerated rehabilitation, and superior cosmetic results. Minimally invasive treatment options in cardiac surgery should always be considered for suitable patients.

Transmyocardial laser revascularization: from randomized trials to clinical practice. A review of techniques, evidence-based outcomes, and future directions

Cardiac surgeons are increasingly faced with a more complex patient who has developed a pattern of diffuse coronary artery disease that cannot be completely revascularized by CAGB alone. Considering the increased operative and long-term cardiac risks predicted by incomplete revascularization, and the documented operative and long-term benefits associated with sole therapy and adjunctive TMR in randomized patients with diffuse coronary artery disease, increased use of sole therapy and adjunctive TMR therapy is warranted.

Transmyocardial laser revascularization

It has been almost a decade since transmyocardial laser revascularization (TMR) was approved for clinical use in the United States. The safety of TMR was demonstrated initially with nonrandomized studies in which TMR was used as the only treatment for patients with severe angina. TMR efficacy was proven after multiple randomized controlled trials. These revealed significant angina relief compared to maximum medical therapy in patients with diffuse coronary disease not amenable to conventional revascularization. In light of these results, TMR has been used as an adjunct to coronary artery bypass grafting (CABG). By definition, patients treated with this combined therapy have more severe coronary disease and comorbidities that are associated with end-stage atherosclerosis. Combination CABG + TMR has resulted in symptomatic improvement without additional risk. The likely mechanism whereby TMR has provided benefit is the angiogenesis engendered by the laser-tissue interaction. Improved perfusion and concomitant improvement in myocardial function have been observed post-TMR. Additional therapies to enhance the angiogenic response include combining TMR with stem cell-based treatments, which appear to be promising future endeavors.

Single versus sequential saphenous vein grafting of the circumflex system: a flowmetric study

OBJECTIVE

We sought to evaluate if patients with proximal critical circumflex (CX) lesions did better with single SV-CABG on the best obtuse marginal (OM), or with sequential SV-CABG on two OM branches.

DESIGN

Ninety patients were prospectively randomised to single SV-CABG on the best OM (sSV-CABG-45 patients; Group A) or to sequential SV-CABG on 2 OM (seqSV-CABG 45 patients; Group B). Transit-time flowmetry (TTF), and graft flow reserve were evaluated. Recurrent angina, acute myocardial infarction, readmission for coronary reintervention were defined "treatment failure" during follow-up.

RESULTS

SeqSV-CABG showed better intraoperative maximum (119.1+/-57.5 ml/min vs. sSV-CABG 62.4+/-29.6; p=0.001), mean (56.3+/-31.5 ml/min vs. 30.8+/-12.8; p=0.0001), minimum flow (22.8+/-9.2 ml/min vs. 11.8+/-8.9; p=0.001) and P.I. (0.71+/-0.4 vs.1.46+/-0.9; p=0.006). Graft flow reserve also proved to be higher (95.4+/-29.7 ml/min mean flow vs. sSV-CABG 42.3+/-15.2 ml/min mean flow; p=0.0001; flow reserve 1.72+/-0.99 vs 1.32+/-1.09; p=0.001) as well as freedom from treatment failure (97.5+/-0.5% vs 88.7+/-0.4%; p=0.05).

CONCLUSIONS

SeqSV-CABG showed higher TTF flows, with no incremental risk for perioperative morbidity. Higher flows and graft flow reserve may allow lower treatment failure at mid-term follow-up.

Endothelial cell-seeded bovine internal mammary artery for complete revascularization

We present a 79-year-old woman with coronary heart disease who underwent complete revascularization by using a No-React bovine internal mammary artery seeded with autologous endothelial cells. Her postoperative course was uneventful, and the patient was recently in New York Heart Association functional class I. Multislice computed tomography imaging showed patent grafts at 20 months of follow-up.

Clinical results of sole therapy TMR treatment

The safety and efficacy of transmyocardial laser revascularization (TMR) is best demonstrated by the data collected from several multi-institutional randomized controlled trials. These trials are an important link between the preclinical data and the most common use of TMR (TMR + Coronary Artery Bypass Grafting). In addition to significant symptomatic relief both short- and long-term objective data were also garnered in these studies. A review of the history, study design, and outcomes is provided.

Transmyocardial laser revascularization as an adjunct to coronary artery bypass grafting

Many patients with angina related to coronary artery disease respond to medical management or can be completely revascularized using available percutaneous coronary interventions or coronary artery bypass grafting (CABG). There is evidence, however, to indicate that up to 25% of patients are incompletely revascularized following CABG and that incomplete revascularization is a significant independent predictor of early and late mortality and adverse events. Transmyocardial revascularization (TMR) is a surgical option for patients with debilitating angina due to coronary artery disease in areas of the heart not amenable to complete revascularization using conventional treatments. In randomized, 1-year controlled trials with long-term follow-up and in additional clinical experience, TMR performed adjunctively to CABG in patients who would be incompletely revascularized by CABG alone has yielded significantly improved clinical outcomes. Based on these published results, the Society of Thoracic Surgeons has issued a practice guideline recommending adjunctive TMR in this difficult patient group.

A review of the application of propensity score methods yielded increasing use, advantages in specific settings, but not substantially different estimates compared with conventional multivariable methods

OBJECTIVE

Propensity score (PS) analyses attempt to control for confounding in nonexperimental studies by adjusting for the likelihood that a given patient is exposed. Such analyses have been proposed to address confounding by indication, but there is little empirical evidence that they achieve better control than conventional multivariate outcome modeling.

STUDY DESIGN AND METHODS

Using PubMed and Science Citation Index, we assessed the use of propensity scores over time and critically evaluated studies published through 2003.

RESULTS

Use of propensity scores increased from a total of 8 reports before 1998 to 71 in 2003. Most of the 177 published studies abstracted assessed medications (N=60) or surgical interventions (N=51), mainly in cardiology and cardiac surgery (N=90). Whether PS methods or conventional outcome models were used to control for confounding had little effect on results in those studies in which such comparison was possible. Only 9 of 69 studies (13%) had an effect estimate that differed by more than 20% from that obtained with a conventional outcome model in all PS analyses presented.

CONCLUSIONS

Publication of results based on propensity score methods has increased dramatically, but there is little evidence that these methods yield substantially different estimates compared with conventional multivariable methods.

Determinants and prognosis of myocardial damage after coronary artery bypass grafting

BACKGROUND

Myocardial infarction remains a devastating complication after coronary revascularization. Although electrocardiography (ECG) and echocardiography suggest transmural infarction, myocardial damage and the quality of myocardial protection are not recognized unless troponin I (TnI) is assessed. Determinants and prognosis of TnI elevation after coronary artery bypass grafting (CABG) were evaluated.

METHODS

Data of 776 consecutive patients undergoing CABG between January 2002 and January 2004 were prospectively exposed to univariate and multivariate analysis. We evaluated the prognosis of patients with all the ECG, echocardiographic, and biochemical criteria for acute myocardial infarction and that of patients with only TnI elevation. Twelve-month follow-up survival and freedom from cardiac events (FCE) were accomplished.

RESULTS

Troponin I greater than 3.1 mug/L at 12 hours was detected in 6.9% of the population, and correlated with lower in-hospital (p < 0.001) and follow-up survival (p = 0.00001), and lower FCE (p = 0.0009). Twenty-one (38.8%) of these fulfilled ECG-echocardiographic criteria (p = 0.05), demonstrating higher TnI values at 12 (p = 0.001), 24 (p = 0.01), 48 (p = 0.01), and 72 (p = 0.04) hours, prolonged ventilation time (p = 0.001), higher in hospital mortality (p = 0.003), lower follow-up survival (p = 0.023), and lower FCE (p = 0.0084). A EuroSCORE greater than 6, ongoing unstable angina, aortic cross-clamp time greater than 90 minutes, cardiopulmonary bypass time greater than 180 minutes, incomplete revascularization, and intraoperative intraaortic balloon pump were independent predictors of myocardial damage (MD) at multivariate analysis. Combined antegrade and retrograde cardioplegia and postoperative enoximone infusion were associated with a lower TnI elevation.

CONCLUSIONS

Troponin I greater than 3.1 mug/L at 12 hours defines perioperative MD. Associated ECG-echocardiographic criteria indicate acute myocardial infarction and anticipate a worse outcome. Identification of predictors for MD is important to develop preventative strategies, as antegrade plus retrograde cardioplegia and enoximone infusion.

Off-Pump Coronary Artery Bypass Grafting Using Only Arterial Grafts in Elderly Patients

BACKGROUND

This study aimed to elucidate the safety and feasibility of off-pump coronary artery bypass grafting with only arterial grafts for elderly patients.

METHODS

Of 653 patients who underwent off-pump coronary artery bypass grafting from April 2000 to December 2003, 581 patients did so with only arterial grafts. The average age was 66.9 +/- 9.3 years. The patients were divided into the elder group E (75 years old or more: 111 cases) or the younger group Y (younger than 75 years old: 470 cases). The mean follow-up term was 21 +/- 12 months.

RESULTS

Additive and logistic EuroSCOREs of group E were significantly higher than those of group Y (p < 0.0001). The number of bypass grafts was 3.3 +/- 0.9 in group E and 3.3 +/- 1.1 in group Y (p = 0.43). The proportion of total revascularization was 74% (82 of 111) in group E and 80% (377 of 470) in group Y (p = 0.15). The number of bilateral implementations of internal thoracic artery was 10 (9.0%) in group E and 196 (42%) in group Y (p < 0.0001). The graft patency rate was 98.7% in group E and 97.8% in group Y (p = 0.96). Hospital mortality was 2.7% (3 of 111) in group E and 0.2% (1 of 470) in group Y (p = 0.095). The causes of death were unrelated to cardiac events. Major adverse cardiac events occurred in 5 patients (5.1%) in group E and in 24 patients (5.6%) in group Y (p > 0.99).

CONCLUSIONS

Off-pump coronary artery bypass grafting using only arterial grafts in elderly patients is as safe and feasible as in young patients.

Impact of Complete Revascularization on Long-Term Survival After Coronary Artery Bypass Grafting in Octogenarians

BACKGROUND

Complete revascularization is important in young patients undergoing coronary artery bypass grafting, but this principle remains less absolute in elderly patients. The purpose of this study was to determine how complete revascularization influenced long-term survival after coronary artery bypass grafting in octogenarians.

METHODS

From 1986 to 2003, 500 consecutive patients 80 to 94 years of age underwent coronary artery bypass grafting. Complete revascularization was defined as placement of at least one graft to each of the three major vascular regions that included a 50% diameter lesion. Revascularization was complete in 400 (80%) patients and incomplete in 100 (20%) patients. Mean (+/- standard deviation) follow-up was 51 +/- 41 months and was 99% complete (2,102 total patient-years).

RESULTS

Operative mortality was 8% +/- 2% (+/-95% confidence interval) and was statistically lower with complete (7% +/- 3%) versus incomplete (13% +/- 7%) revascularization (p < 0.05). Of 459 operative survivors, there were 261 late deaths. Multivariate regression analysis identified six independent predictors of late death: earlier operative year, male sex, peripheral or cerebrovascular disease, congestive heart failure, and incomplete revascularization (p < 0.03 for all). Excluding operative deaths, mean survival (Kaplan-Meier) was 82 months with complete revascularization compared with 65 months with incomplete revascularization (p < 0.008). Survival was 62% +/- 3% with complete versus 45% +/- 6% with incomplete revascularization at 5 years and 39% +/- 3% with complete versus 25% +/- 6% with incomplete revascularization at 8 years (p < 0.008).

CONCLUSIONS

In octogenarians undergoing coronary artery bypass grafting, complete revascularization correlated with improved long-term survival, increasing mean survival by almost 25% compared with incomplete revascularization.

Principles for modeling propensity scores in medical research: a systematic literature review

PURPOSE

To document which established criteria for logistic regression modeling researchers consider when using propensity scores in observational studies.

METHODS

We performed a systematic review searching Medline and Science Citation to identify observational studies published in 2001 that addressed clinical questions using propensity score methods to adjust for treatment assignment. We abstracted aspects of propensity score model development (e.g. variable selection criteria, continuous variables included in correct functional form, interaction inclusion criteria), model discrimination and goodness of fit for 47 studies meeting inclusion criteria.

RESULTS

We found few studies reporting on the propensity score model development or evaluation of model fit.

CONCLUSIONS

Reporting of aspects related to propensity score model development is limited and raises questions about the value of these principles in developing propensity scores from which unbiased treatment effects are estimated.

Propensity score methods gave similar results to traditional regression modeling in observational studies: a systematic review

OBJECTIVE

To determine whether adjusting for confounder bias in observational studies using propensity scores gives different results than using traditional regression modeling.

METHODS

Medline and Embase were used to identify studies that described at least one association between an exposure and an outcome using both traditional regression and propensity score methods to control for confounding. From 43 studies, 78 exposure-outcome associations were found. Measures of the quality of propensity score implementation were determined. The statistical significance of each association using both analytical methods was compared. The odds or hazard ratios derived using both methods were compared quantitatively.

RESULTS

Statistical significance differed between regression and propensity score methods for only 8 of the associations (10%), kappa = 0.79 (95% CI = 0.65-0.92). In all cases, the regression method gave a statistically significant association not observed with the propensity score method. The odds or hazard ratio derived using propensity scores was, on average, 6.4% closer to unity than that derived using traditional regression.

CONCLUSIONS

Observational studies had similar results whether using traditional regression or propensity scores to adjust for confounding. Propensity scores gave slightly weaker associations; however, many of the reviewed studies did not implement propensity scores well.