Evaluation of revascularization subtypes in octogenarians undergoing coronary artery bypass grafting

What does complete revascularization mean in 2021? - Definitions, implications, and biases

PURPOSE OF REVIEW

Coronary revascularization is known to be an excellent treatment for coronary artery disease. However, whether incomplete myocardial revascularization compromises long-term outcomes, as compared to complete revascularization (CR), remains contentious. Herein, we review the concept of and evidence on CR/incomplete revascularization (ICR) and discuss future perspectives.

RECENT FINDINGS

When possible, achieving CR in coronary artery bypass grafting is desirable; nonetheless, ICR is also a reasonable option to balance the therapeutic benefits against the risks.

SUMMARY

Although angiography-based assessment currently remains the standard of care, fractional flow reserve guidance may reduce the number of lesions requiring revascularization, which may be helpful for an appropriate surgical revascularization strategy. In particular, utilizing this approach may refine hybrid revascularization procedures, especially among high-risk patients.

Complete surgical revascularization: Different definitions, same impact?

BACKGROUND

There are several different definitions of complete revascularization on coronary surgery across the literature. Despite the importance of this definition, there is no agreement on which one has the most impact. The aim of this study was to evaluate which definition of complete surgical revascularization correlates with early and late outcomes.

METHODS

All consecutive patients submitted to isolated CABG from 2012 to 2016 with previous myocardial scintigraphy were evaluated.

EXCLUSION CRITERIA

emergent procedures and previous cardiac surgery procedures. The population of 162 patients, follow-up complete in 100% patients; median 5.5; IQR: 4.4-6.9 years. Each and all of the 162 patients were classified as complying or not with the four different definitions: numerical, functional, anatomical conditional, and anatomical unconditional. Perioperative outcome: MACCE; long-term outcomes: survival and repeat revascularization. Univariable and multivariable analyses were developed to detect predictors of outcomes.

RESULTS

Complete functional revascularization was a predictor of increased survival (HR: 0.47; CI 95: 0.226-0.969; p = .041). No other definitions showed effect on follow-up mortality. Age and cardiac dysfunction increased long-term mortality. The definition of complete revascularization did not have an impact on MACCE or the need for revascularization CONCLUSIONS: A uniformly accepted definition of complete coronary revascularization is lacking. This study raises awareness about the importance of viability guidance for CABG.

Complete revascularization determined by myocardial perfusion imaging could improve the outcomes of patients with stable coronary artery disease, compared with incomplete revascularization and no revascularization

OBJECTIVES

To compare the outcomes among patients treated by complete coronary revascularization (CCR) or incomplete coronary revascularization (ICR) and no coronary revascularization (NCR) by myocardial perfusion imaging (MPI), as well as to evaluate the impact of severity of ischemia on patients with coronary artery disease (CAD) by different therapy strategies.

BACKGROUND

Using myocardial ischemia severity determined by MPI guiding treatment strategies for CAD patients still lacks strong clinical evidences.

METHODS

Consecutive patients (N = 286) underwent clinical stress-rest SPECT MPI and were retrospectively followed-up. For assessment of outcome of treatment, all patients were classified into three groups (CCR, ICR, and NCR), and further divided into two subgroups as mild ischemia (< 10% ischemic myocardium) and moderate-severe ischemia (≥ 10% ischemic myocardium). All-cause death was defined as the primary endpoint, and the composite of deaths, nonfatal myocardial infarction, and repeat revascularization (MACE) as the secondary endpoint.

RESULTS

Two-hundred eighty-six patients were followed-up for 46 ± 21 months. Thirty deaths and 65 MACEs were recorded. Patients treated by revascularization had significantly lower MACE (P < .001) but not mortality (P = .158) than patients treated by NCR. Outcomes of CCR related to mortality rate were greater than ICR and NCR (death: P = .019, MACE: P < .001). In patients with moderate-severe ischemia, CCR showed improved outcomes than ICR and NCR (death: P = .034; and MACE: P < .001). In patients with mild ischemia, the outcomes of CCR, ICR, and NCR had no significant difference (P > .05). Multivariate regression Cox analysis revealed that summed difference score [death: HR 1.09 (1.03, 1.15), P = .004] was an independent risk factor and CCR was an independent negative predictor [death: HR 0.31 (0.12, 0.81), P = .017; MACE: HR 0.30 (0.16, 0.57), P < .001].

CONCLUSIONS

Outcomes of patients treated by CCR were most likely more promising in comparison with treatment of ICR and NCR, especially when patients had over 10% ischemic myocardium.

Predicting operative mortality in octogenarians for isolated coronary artery bypass grafting surgery: a retrospective study

Background

Available cardiac surgery risk scores have not been validated in octogenarians. Our objective was to compare the predictive ability of the Society of Thoracic Surgeons (STS) score, EuroSCORE I, and EuroSCORE II in elderly patients undergoing isolated coronary artery bypass grafting surgery (CABG).

Methods

All patients who underwent isolated CABG (2002 – 2008) were identified from the Alberta Provincial Project for Outcomes Assessment in Coronary Heart Disease (APPROACH) registry. All patients aged 80 and older (n = 304) were then matched 1:2 with a randomly selected control group of patients under age 80 (n = 608 of 4732). Risk scores were calculated. Discriminatory accuracy of the risk models was assessed by plotting the areas under the receiver operator characteristic (AUC) and comparing the observed to predicted operative mortality.

Results

Octogenarians had a significantly higher predicted mortality by STS Score (3 ± 2% vs. 1 ± 1%; p < 0.001), additive EuroSCORE (8 ± 3% vs. 4 ± 3%; p < 0.001), logistic EuroSCORE (15 ± 14% vs. 5 ± 6%; p < 0.001), and EuroSCORE II (4 ± 3% vs. 2 ± 2%; p < 0.001) compared to patients under age 80 years. Observed mortality was 2% and 1% for patients age 80 and older and under age 80, respectively (p = 0.323). AUC revealed areas for STS, additive and logistic EuroSCORE I and EuroSCORE II, respectively, for patients age 80 and older (0.671, 0.709, 0.694, 0.794) and under age 80 (0.829, 0.750, 0.785, 0.845).

Conclusion

All risk prediction models assessed overestimated surgical risk, particularly in octogenarians. EuroSCORE II demonstrated better discriminatory accuracy in this population. Inclusion of new variables into these risk models, such as frailty, may allow for more accurate prediction of true operative risk.

Revascularization in ischemic heart failure with reduced left ventricular ejection fraction. The impact of complete revascularization

Heart failure is a growing problem worldwide, with coronary artery disease being the underlying cause of over two-thirds of cases. Revascularization in this group of patients may potentially inhibit the progressive damage to the myocardium and lead to improved outcomes, but data in this area are scarce. This article emphasizes the role of qualification for revascularization and selection of method (percutaneous coronary intervention vs. coronary artery bypass grafting) and subsequently focuses on the issue of completeness of revascularization in this group of patients.

Arterial grafts balance survival between incomplete and complete revascularization: a series of 1000 consecutive coronary artery bypass graft patients with 98% arterial grafts

OBJECTIVE

Coronary artery bypass grafting (CABG) with incomplete revascularization (ICR) is thought to decrease survival. We studied the survival of patients with ICR undergoing total arterial grafting.

METHODS

In a consecutive series of all-comer 1000 patients with isolated CABG, operative and midterm survival were assessed for patients undergoing complete versus ICR, with odds ratios and hazard ratios, adjusted for European System for Cardiac Operative Risk Evaluation category, CABG urgency, age, and comorbidities.

RESULTS

In this series of 1000 patients with 98% arterial grafts (2922 arterial, 59 vein grafts), 73% of patients with multivessel disease received bilateral internal mammary artery grafts. ICR occurred in 140 patients (14%). Operative mortality was 3.8% overall, 8.6% for patients with ICR, and 3.2% for patients with complete revascularization (P = .008). For operative mortality using multivariable logistic regression, after controlling for European System for Cardiac Operative Risk Evaluation category (P < .001) and CABG urgency (P = .03), there was no evidence of a statistically significant increased risk of death due to ICR (odds ratio, 1.73; 95% confidence interval, 0.80-3.77). For midterm follow-up (median, 54 months [interquartile range, 27-85 months]), after controlling for European System for Cardiac Operative Risk Evaluation category (P < .001) and comorbidities (P = .017) there was a significant interaction between age ≥ 80 years and ICR (P = .017) in predicting mortality. The adjusted hazard ratio associated with ICR for patients older than age 80 years was 5.7 (95% confidence interval, 1.8-18.0) versus 1.2 (95% confidence interval, 0.7-2.1) for younger patients.

CONCLUSIONS

This is the first study to suggest that ICR in patients with mostly arterial grafts is not associated with decreased survival perioperatively and at midterm in patients younger than age 80 years. Arterial grafting, because of longevity, may balance survival between complete revascularization and ICR.

Effect of complete revascularization on 10-year survival of patients with stable multivessel coronary artery disease: MASS II trial

BACKGROUND

The importance of complete revascularization remains unclear and contradictory. This current investigation compares the effect of complete revascularization on 10-year survival of patients with stable multivessel coronary artery disease (CAD) who were randomly assigned to percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG).

METHODS AND RESULTS

This is a post hoc analysis of the Second Medicine, Angioplasty, or Surgery Study (MASS II), which is a randomized trial comparing treatments in patients with stable multivessel CAD, and preserved systolic ventricular function. We analyzed patients who underwent surgery (CABG) or stent angioplasty (PCI). The survival free of overall mortality of patients who underwent complete (CR) or incomplete revascularization (IR) was compared. Of the 408 patients randomly assigned to mechanical revascularization, 390 patients (95.6%) underwent the assigned treatment; complete revascularization was achieved in 224 patients (57.4%), 63.8% of those in the CABG group and 36.2% in the PCI group (P=0.001). The IR group had more prior myocardial infarction than the CR group (56.2% × 39.2%, P=0.01). During a 10-year follow-up, the survival free of cardiovascular mortality was significantly different among patients in the 2 groups (CR, 90.6% versus IR, 84.4%; P=0.04). This was mainly driven by an increased cardiovascular specific mortality in individuals with incomplete revascularization submitted to PCI (P=0.05).

CONCLUSIONS

Our study suggests that in 10-year follow-up, CR compared with IR was associated with reduced cardiovascular mortality, especially due to a higher increase in cardiovascular-specific mortality in individuals submitted to PCI.

CLINICAL TRIAL REGISTRATION INFORMATION

URL: http://www.controlled-trials.com.

REGISTRATION NUMBER

ISRCTN66068876.

Completeness of revascularization and survival among octogenarians with triple-vessel disease

BACKGROUND

We sought to determine the impact of the completeness of surgical revascularization among octogenarians with triple-vessel disease.

METHODS

Between 1992 and 2008, 476 consecutive patients aged 80 years or more who underwent primary isolated coronary artery bypass grafting (CABG) procedures were identified. Early and late survival were compared among patients who underwent complete revascularization (CR, n=391) and incomplete revascularization (IR, n=85). IR was present when 1 or more of the 3 main coronary arteries with 50% or greater stenosis that were identified preoperatively as a surgical target by the operating surgeon were not grafted. The mean follow-up was 5.4±3.0 years (maximum 15.3 years).

RESULTS

Baseline risk was similar between the 2 groups of patients. IR was more frequent in off-pump compared with on-pump CABG (34.9% versus 16.2%, respectively; p=0.002). The most common reason for IR was small or severely diseased arteries (87%). The incidence of postoperative myocardial infarction (MI) was similar in both groups (CR, 18.4% versus IR, 17.3%; p=0.81). In-hospital mortality was 7.2% among patients with CR and 4.7% among patients with IR (p=0.60). Three, 5-, and 8-year freedom from all-cause mortality among patients who underwent CR were 89.2%, 74.1%, and 54.3%, respectively, and were not significantly different from those patients who underwent IR (86.6%, 74.5%, and 49.4%, respectively) (p=0.40).

CONCLUSIONS

In octogenarians with triple-vessel disease, a strategy of incomplete revascularization during CABG does not negatively impact early or long-term survival.

Differential modulation of right ventricular strain and right atrial mechanics in mild vs. severe pressure overload

Increased right atrial (RA) and ventricular (RV) chamber volumes are a late maladaptive response to chronic pulmonary hypertension. The purpose of the current investigation was to characterize the early compensatory changes that occur in the right heart during chronic RV pressure overload before the development of chamber dilation. Magnetic resonance imaging with radiofrequency tissue tagging was performed on dogs at baseline and after 10 wk of pulmonary artery banding to yield either mild RV pressure overload (36% rise in RV pressure; n = 5) or severe overload (250% rise in RV pressure; n = 4). The RV free wall was divided into three segments within a midventricular plane, and circumferential myocardial strain was calculated for each segment, the septum, and the left ventricle. Chamber volumes were calculated from stacked MRI images, and RA mechanics were characterized by calculating the RA reservoir, conduit, and pump contribution to RV filling. With mild RV overload, there were no changes in RV strain or RA function. With severe RV overload, RV circumferential strain diminished by 62% anterior (P = 0.04), 42% inferior (P = 0.03), and 50% in the septum (P = 0.02), with no change in the left ventricle (P = 0.12). RV filling became more dependent on RA conduit function, which increased from 30 ± 9 to 43 ± 13% (P = 0.01), than on RA reservoir function, which decreased from 47 ± 6 to 33 ± 4% (P = 0.04), with no change in RA pump function (P = 0.94). RA and RV volumes and RV ejection fraction were unchanged from baseline during either mild (P > 0.10) or severe RV pressure overload (P > 0.53). In response to severe RV pressure overload, RV myocardial strain is segmentally diminished and RV filling becomes more dependent on RA conduit rather than reservoir function. These compensatory mechanisms of the right heart occur early in chronic RV pressure overload before chamber dilation develops.

[Update on geriatric cardiology]

This article contains a review of the main developments in the field of geriatric cardiology reported during 2010. The focus is on research into the specific characteristics of elderly patients with heart failure, ischemic heart disease, valvular heart disease and arrhythmias.

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.