Anoar Zacharias

Improved Survival With Radial Artery Versus Vein Conduits in Coronary Bypass Surgery With Left Internal Thoracic Artery to Left Anterior Descending Artery Grafting

Background—Given its proven survival benefit, left internal thoracic artery to left anterior descending (LITA-LAD) grafting has become a fundamental part of CABG. This grafting also led to increased use of other arterial conduits, of which the radial artery is most popular. Whether radial grafting improves survival beyond that achieved by LITA-LAD alone is not known. Methods and Results—We compared 6-year outcomes in propensity-matched CABG-LITA-LAD patients (925 each) divided into those with ≥1 radial grafts and those with vein-only grafting. Matched patients had essentially identical demographics, comorbidities, coronary disease, and operative data. Perioperative outcomes, including death (radial, 11 [1.2%]; vein, 10 [1.1%]), were similar for the 2 groups. Cumulative 0- to 6-year survival was better for radial patients (risk ratio, 0.675), particularly after 3 years (P <0.03). Six-year survival in vein (86.8%) and radial (92.1%) patients indicated 67% greater overall vein mortality. Incidence rates of radial and vein repeated catheterization (190 of 925 [20.5%] versus 199 of 925 [21.5%]) and revascularization (8.8% versus 8.5%) were similar. Angiography data in restudied symptomatic patients showed a trend for greater radial patency. Vein failure (66 of 161 [41%]) was significantly worse than radial failure (46 of 157 [29.3%]) in patients receiving both types of grafts (P =0.039). Conclusions—Using radial as a second arterial conduit in CABG-LITA-LAD as opposed to vein grafting improves long-term outcomes as a result of decreased late deaths, especially after the third postoperative year.

Obesity and risk of new-onset atrial fibrillation after cardiac surgery.

Background— New-onset postoperative atrial fibrillation (AF) is a common complication of cardiac surgery that has substantial effects on outcomes. In the general (nonsurgical) adult population, AF has been linked to increasing obesity, which correlates with left atrial enlargement. It is not known whether postoperative AF is similarly linked to obesity. Methods and Results— This was a retrospective analysis of the incidence of AF in terms of body mass index (BMI). A total of 8051 consecutive cardiac surgery patients (1994 to 2004; mean age 64 [SD 11] years; 5372 men [67%]) who were free of any history of preoperative AF or flutter were included in the analysis. This series included 3164 obese patients (39%; median age 62 years) and 4887 nonobese patients (61%; median age 66 years), who were further divided on the basis of BMI (kg/m2) into 6 groups: BMI <22 kg/m2, 22≤BMI≤25 kg/m2 (normal), 2540 kg/m2 (obese III). Unadjusted AF incidence was similar in obese and nonobese patients (n=742 [23.5%] versus n=1068 [21.9%], respectively; P=0.099). Covariate-adjusted ORs for AF were systematically greater for larger patients than for patients in the normal group (adjusted OR [95% CI]=1.18 [1.00 to 1.40], 1.36 [1.14 to 1.63], 1.69 [1.35 to 2.11], and 2.39 [1.81 to 3.17] for overweight, obese I, obese II, and obese III, respectively). Other AF predictors included age (adjusted OR=1.52 [95% CI 1.46 to 1.58] per 10 years), mitral valve surgery (adjusted OR=2.42 [95% CI 1.92 to 3.06]), aortic valve surgery (adjusted OR=1.79 [95% CI 1.45 to 2.22]), chronic obstructive pulmonary disease (adjusted OR=1.28 [95% CI 1.12 to 1.46]), male gender (adjusted OR=1.24 [95% CI 1.10 to 1.40]), preoperative &bgr;-blocker use (adjusted OR=1.17 [95% CI 1.05 to 1.32]), vascular disease (adjusted OR=1.18 [95% CI 1.05 to 1.32]), white race (adjusted OR=1.33 [95% CI 1.07 to 1.66]), history of arrhythmia other than AF/flutter (adjusted OR=0.80 [95% CI 0.68 to 0.96]), ejection fraction <40% (adjusted OR=1.16 [95% CI 1.03 to 1.31]), left main disease (adjusted OR=1.15 [95% CI 1.00 to 1.32]), and off-pump surgery (adjusted OR=0.61 [95% CI 0.44 to 0.83]). The obesity-AF association was confirmed in 4 1-to-1 propensity-matched obese versus nonobese comparisons and in 2 separate derivation/validation subcohort analyses. Conclusions— Obesity is an important determinant of new-onset AF after cardiac surgery. Future postoperative AF risk models should incorporate BMI or obesity levels. Studies examining the efficacy of AF-minimizing prophylactic interventions in high-BMI patients, particularly in the elderly, may be warranted.

Determinants of prolonged mechanical ventilation after coronary artery bypass grafting

BACKGROUND Early extubation of cardiac surgical patients enhances ambulation, improves cardiopulmonary function, and can lead to savings in health care costs. METHODS We retrospectively examined the role of 48 variables in determining the period of ventilatory support in 507 patients having coronary artery bypass grafting. RESULTS Fifteen (< 3%) of 507 patients required ventilatory support in excess of 24 hours. Among the remaining patients, extubation was achieved early (< or = 8 hours) (mean time, 5.65 +/- 1.31 hours) in 53% and late (> 8 hours) (mean time, 13.7 +/- 3.4 hours) in 47%. Logistic and linear multivariate regression analyses implicated increased age, New York Heart Association functional class IV, intraoperative fluid retention, postoperative intraaortic balloon pump requirement, and bank blood transfusions as predictors of late extubation. Also, the linear regression linked lower body weight and number of anastomoses (or grafts) to increased mechanical ventilatory support. CONCLUSIONS Analysis of the fluid balance and cardiopulmonary bypass data suggests that earlier extubation may be achieved by actively reducing fluid retention (eg, by hemoconcentration) and time on bypass (eg, normothermia). Finally, intensive care unit stay and postoperative length of stay were significantly lower in the early versus late extubation groups without an increase in pulmonary complications.

Late Results of Conventional Versus All-Arterial Revascularization Based on Internal Thoracic and Radial Artery Grafting

BACKGROUND Use of one or more arterial grafts to revascularize two-vessel and three-vessel coronary artery disease has been shown to improve coronary artery bypass graft surgery (CABG) survival. Yet, the presumed long-term survival benefits of all-arterial CABG have not been quantified. METHODS We compared propensity-adjusted 12-year survival in two contemporaneous multivessel primary CABG cohorts with all patients receiving 2 or more grafts: (1) all-arterial cohort (n = 612; 297 three-vessel disease [49%]); and (2) single internal thoracic artery (ITA) plus saphenous vein (SV) cohort (n = 4,131; 3,187 three-vessel disease [77%]). RESULTS Early (30-day) deaths were similar for the all-arterial and ITA/SV cohorts (8 [1.30%] versus 69 [1.67%]) whereas late mortality was substantially greater for the ITA/SV cohort (85 [13.9%] versus 1,216 [29.4%]; p < 0.0001). The risk-adjusted 12-year survival was significantly better for all-arterial (with a risk ratio [RR] = 0.60; 95% confidence interval [CI]: 0.48 to 0.75; p < 0.001), but this benefit was true only for three-vessel disease (RR = 0.58; 95% CI: 0.43 to 0.78; p < 0.001) and not for two-vessel disease (RR = 0.97; 95% CI: 0.66 to 1.43; p = 0.89). The all-arterial survival benefit was also true for varying risk subcohorts: no diabetes mellitus (RR = 0.50; 95% CI: 0.37 to 0.69), diabetes mellitus (RR = 0.77; 95% CI: 0.56 to 1.07), ejection fraction 40% or greater (RR = 0.60; 95% CI: 0.45 to 0.78), and ejection fraction less than 40% (RR = 0.62; 95% CI: 0.40 to 0.98). Lastly, the multivariate analysis indicated a strong long-term effect of completeness of revascularization, particularly for all-arterial patients, so that compared with patients with two grafts, survival was significantly better when three grafts (RR = 0.54; 95% CI: 0.33 to 0.87) or four grafts (RR = 0.40; 95% CI: 0.21 to 0.76) were completed. CONCLUSIONS All-arterial revascularization is associated with significantly better 12-year survival compared with the standard single ITA with saphenous vein CABG operation, in particular for triple-vessel disease patients. The completeness of revascularization of the underlying coronary disease is critical for maximizing the long-term benefits of arterial-only grafting.

Long-term survival and health status after prolonged mechanical ventilation after cardiac surgery.

ObjectiveTo determine hospital mortality, weaning from mechanical ventilation, long-term survival, and functional health status in patients receiving ≥7 days of mechanical ventilation after cardiac surgery. DesignRetrospective chart review and prospective patient interviews. SettingA university-affiliated, tertiary care medical center. PatientsA total of 124 patients that received ≥7 days of mechanical ventilation after cardiac surgery. InterventionsNone. Main Outcome MeasuresHospital and long-term death, liberation from mechanical ventilation, and functional health status. Measurements and Main ResultsA total of 19 (15%) patients died in hospital. Of the 105 survivors, 104 (99%) were completely weaned from mechanical ventilation. Patients who died in the hospital were more likely to have had a preoperative stroke or to have a new postoperative stroke, more likely to have postoperative renal failure, and less likely to have chronic obstructive pulmonary disease. Kaplan-Meier survival was 59% at 5 yrs and expected median survival was 6.2 yrs. Patients who died anytime after discharge were more likely to have preoperative renal dysfunction or stroke, took longer to be weaned from mechanical ventilation and to be discharged, and were more likely to have postoperative complications such as stroke or renal dysfunction. Also, they were more likely to be too debilitated to walk or eat. By multivariate analysis, admitting creatinine, aortic valve surgery, number of ventilator days, and discharged on tube feedings remained significant predictors of mortality. A total of 40 of 53 survivors were interviewed. Participants were similar to nonparticipants (p > .10 for all characteristics). A few (16%) had limitations of their activities of daily living (eating, dressing, bathing), and most had limitations of moderate activity (60%) and vigorous activity (94%). Only 36% could climb stairs or walk uphill without limitations, 54% could walk a block, and 41% had no limitations in house or job work. Half the participants had no body pain; 38% had moderate and 4% severe pain. Most (59%) described their general health as good to excellent. Only 10% said it was poor. ConclusionPatients’ chances of being liberated from mechanical ventilation are excellent. Their long-term survival and health status are good.

Variables Predicting Reintubation After Cardiac Surgical Procedures

BACKGROUND This study sought to determine patient characteristics, processes of care, and intermediate outcomes as predictors of reintubation after cardiac surgical procedures. METHODS We performed a retrospective case-control study that included all patients undergoing cardiac surgical intervention who required reintubation and an equal number of control patients not requiring reintubation. Putative risk factors were analyzed univariately by chi2, Fisher exact, Students t, or Mann-Whitney tests. A logistic regression model was developed using data from patients requiring reintubation for cardiorespiratory reasons. RESULTS Of the 1,000 consecutive patients reviewed, 41 (4.1%) required reintubation (30 [3%] for cardiorespiratory reasons and 11 [1.1] for unplanned operations). Univariate predictors of reintubation (p<0.05) were older age, chronic obstructive pulmonary disease, New York Heart Association functional class IV, preoperative renal failure, lower arterial oxygen tension, insertion of intraaortic balloon pump, longer time in the operating room, longer duration of cardiopulmonary bypass times, positive fluid balance, postoperative renal failure, and worse pulmonary mechanics. Patients requiring reintubation also required a longer initial period of mechanical ventilation (median, 16.3 versus 6.0 hours; p<0.05). Excellent prediction was found with a model consisting of four variables: operating room time, respiratory rate, vital capacity, and chronic obstructive pulmonary disease. CONCLUSIONS Patients who required reintubation were sicker and had worse respiratory function and more comorbidity. Prompt extubation did not contribute to reintubation. Patients identified as having a high risk for reintubation should be followed up closely, and interventions should be directed to treating the problems leading to reintubation.

Sequential Radial Artery Grafts for Multivessel Coronary Artery Bypass Graft Surgery: 10-Year Survival and Angiography Results

BACKGROUND Increasing the number of arterial grafts for coronary artery bypass grafting (CABG) has been linked to improved late survival. Currently, it is not known if these long-term benefits are also true when sequential radial artery (RA) grafts are the primary means to maximizing arterial revascularization. METHODS We compared late survival of 532 consecutive patients receiving sequential RA grafts (sequential RA group: 438 men; 462 with three-vessel disease) with that of a 4,131 contemporaneous internal thoracic artery (ITA) with saphenous vein (SV) multivessel CABG cohort (conventional group). Graft failure rates were determined from symptom-driven repeat angiography films in 122 sequential RA patients performed 2 to 4,317 days after surgery. Median survival sequential RA follow-up was 5.3 years (range, 0.5 to 12.3). RESULTS The sequential RA patients received a total of 1,181 RA grafts (538 sequential [30 triple] and 75 single) along with 636 SV and 533 ITA. Overall RA graft failure (80 of 272; 29%) was intermediate to that for ITA (7 of 121; 5.8%; p < 0.001) and vein (54 of 133, 41.6%; p = 0.032) grafts. Sequential versus nonsequential RA failure did not differ (77 of 252 [31%] versus 3 of 20 [15%]; p = 0.202), while failure of the proximal (36 of 123; 29%) and distal (40 of 129; 31%) components of sequential RA grafts were essentially identical. A total of 69 deaths (6 operative; 1.1%) have occurred in the sequential RA cohort. Unadjusted 10-year sequential RA cohort survival was 76.2% overall, and 79.0% for the 454 primary isolated CABG subgroup. The risk-adjusted 10-year survival using a logit propensity score was substantially better for the sequential RA cohort versus the conventional CABG cohort (risk ratio [95% confidence interval] 0.61 [0.44 to 0.85]; p = 0.003). CONCLUSIONS Sequential RA grafting is a safe method for maximizing arterial revascularization and is associated with excellent 10-year survival that seems to be superior to conventional or ITA/SV CABG results. Also, the similar proximal and distal sequential RA patency mitigates concerns of a clinically significant effect of increased vasoreactivity of distal segments of RA conduits.

Late outcomes after radial artery versus saphenous vein grafting during reoperative coronary artery bypass surgery

OBJECTIVE We investigated whether use of radial artery versus saphenous vein grafts during coronary artery bypass grafting reoperations is associated with a significant long-term survival benefit. METHODS We reviewed a series of 347 consecutive coronary artery bypass grafting reoperations (1996-2007; 270 [78%] male patients; age, 65.3 +/- 9.2 years). Internal thoracic artery grafts were used in 248 (71%) patients at the time of the first coronary artery bypass grafting operation and in 154 (44%) patients at reoperation. Patients were grouped based on whether a functional radial artery graft was present after coronary artery bypass grafting reoperation (radial artery cohort, n = 203 [59%]) or not (saphenous vein cohort, n = 144 [41%]). Median time to reoperation was similar for the radial artery (10.3 years) and saphenous vein (10.1 years) cohorts (P = .55). Angiographic data were used to ascertain the number and type of grafts that remained functional from initial coronary artery bypass grafting. Survival data (< or = 12 years) were time segmented based on multiphase hazard modeling at 90 days, and late survival was then analyzed by using proportional hazard Cox regression, with risk adjustment based on a radial artery-use propensity score computed from 48 covariates, including time to reoperation, month of surgical intervention, and total arterial and vein grafts after reoperation. Propensity-matched and propensity quintile comparisons were also done. RESULTS Follow-up was similar for the radial artery versus saphenous vein cohorts (5.7 +/- 3.4 vs 5.8 +/- 4.0 years, P = .86), and 112 (50 in the radial artery and 62 in the saphenous vein cohorts) deaths were documented. Early mortality (< or = 90 days) did not differ for the radial artery (7.4%) and saphenous vein (12.5%) cohorts (P = .14). Unadjusted late outcomes were superior for the radial artery versus saphenous vein cohorts, with survival of 97.3% versus 92.9%, 84.9% versus 77.2%, and 74.1% versus 60.3% at 1, 5, and 10 years, respectively. Propensity-adjusted radial artery survival was superior, with a hazard ratio of 0.58 (P = .04), and this result was confirmed in a propensity-matched comparison. CONCLUSIONS We conclude that the use of radial artery as opposed to saphenous vein grafting for reoperative coronary artery bypass grafting, either with or without concomitant internal thoracic artery grafts, is associated with a substantial improvement in late survival. This benefit is likely derived from the increased overall number of arterial grafts.

Protection of the right internal mammary artery in the retorsternal position with stented grafts

One of the limiting factors for the use of the right internal mammary artery as a pedicle graft to the anterolateral vessels of the left coronary system is the necessary midline crossover and the close proximity to the sternum. In this setting, the right internal mammary artery pedicle is at increased risk of injury during sternal reentry and dissection. A technique is described where stented polytetrafluoroethylene grafts were used to shield right internal mammary artery pedicles. There were no operative deaths or polytetrafluoroethylene-related complications. The right internal mammary artery was patent with its target vessel well perfused in 6 restudied patients.