Yvon R. Baribeau

Determination of Etiologic Mechanisms of Strokes Secondary to Coronary Artery Bypass Graft Surgery

Background and Purpose— Current research focused on stroke in the setting of coronary artery bypass graft (CABG) surgery has missed important opportunities for additional understanding by failing to consider the range of different stroke mechanisms. We developed and implemented a classification system to identify the distribution and timing of stroke subtypes. Methods— We conducted a regional study of 388 patients with the diagnosis of stroke after isolated CABG surgery in northern New England from 1992 to 2000. Data were collected on patient and disease characteristics, intraoperative and postoperative care, and outcomes. Stroke etiology was classified into 1 of the following: hemorrhage, thromboembolic (embolic, thrombotic, lacunar), hypoperfusion, other (subtype not listed above), multiple (≥2 competing mechanisms), or unclassified (unknown mechanism). The reliability of the classification system was determined by percent agreement and &kgr; statistics. Results— Embolic strokes accounted for 62.1% of strokes, followed by multiple etiologies (10.1%), hypoperfusion (8.8%), lacunar (3.1%), thrombotic (1.0%), and hemorrhage (1.0%). There were 54 strokes with unknown etiology (13.9%). There were no strokes classified as “other.” Nearly 45% (105/235) of the embolic and 56% (18/32) of hypoperfusion strokes occurred within the first postoperative day. Conclusions— We used a locally developed classification system to determine the etiologic mechanism of 388 strokes secondary to CABG surgery. The principal etiologic mechanism was embolic, followed by stroke having multiple mechanisms and hypoperfusion. Regardless of mechanism, strokes predominantly occurred within the first postoperative day.

Comparing long-term survival of patients with multivessel coronary disease after CABG or PCI: Analysis of BARI-like patients in Northern New England

Background—Randomized trials comparing coronary artery bypass graft surgery (CABG) with percutaneous coronary interventions (PCIs) for patients with multivessel coronary disease (MVD) report similar long-term survival for CABG and PCI. These studies used a highly selected population of patients and providers, and their results may not be generalizable to actual care. Our goal in this study was to compare long-term survival of MVD patients treated with CABG vs PCI in contemporary practice. Methods and Results—From our northern New England registries of consecutive coronary revascularizations, we identified 10 198 CABG and 4295 PCI patients with MVD who may have been eligible for either procedure between 1994 and 2001. Vital status was obtained by linkage to the National Death Index. Proportional-hazards regression was used to calculate hazard ratios (HRs) for survival in CABG vs PCI patients after adjustment for comorbidities and disease characteristics. CABG patients were older; had more comorbidities, more 3-vessel disease, and lower ejection fractions; and were more completely revascularized. Adjusted long-term survival for patients with 3-vessel disease was better after CABG than PCI (HR, 0.60; P<0.01) but not for patients with 2-vessel disease (HR, 0.98; P=0.77). The survival advantage of CABG for 3-vessel disease patients was present in all patient populations, including women, diabetics, and the elderly and in the era of high stent utilization. Conclusions—In contemporary practice, survival for patients with 3-vessel coronary disease is better after CABG than PCI, an observation that patients and physicians should carefully consider when deciding on a revascularization strategy.

In-hospital outcomes of off-pump versus on-pump coronary artery bypass procedures: a multicenter experience ☆

BACKGROUNDnConcern about the possible adverse effects of the cardiopulmonary bypass (CPB) pump and advances in retractors and operative techniques to access all coronary segments have resulted in increased interest in off-pump coronary artery bypass (OPCAB) procedures. Four of the Northern New England Cardiovascular Disease Study Group centers initiated OPCAB programs in 1998. We compared the preoperative risk profiles and in-hospital outcomes of patients done off-pump with those done by conventional coronary artery bypass (CCAB) with CPB.nnnMETHODSnBetween 1998 and 2000, 1,741 OPCAB and 6,126 CCAB procedures were performed at these four medical centers. Minimally invasive direct coronary artery bypass grafting procedures were excluded. Data were available for patient and disease risk factors, extent of coronary disease and adverse in-hospital outcomes.nnnRESULTSnThe OPCAB and CCAB groups were somewhat different in their preoperative patient and disease characteristics. The OPCAB patients were more likely to be female and to have peripheral vascular disease. The CCAB patients were more likely to have an ejection fraction less than 0.40 and be urgent or emergent at operation. However, overall predicted risk of in-hospital mortality, based on preoperative factors, was similar in the OPCAB and CCAB groups; the mean predicted risk was 2.6% (p = 0.567). Crude rates of mortality (2.54% OPCAB versus 2.57%, CCAB), intraoperative or postoperative stroke (1.33% versus 1.82%), mediastinitis (1.10% versus 1.37%), and return to the operating room for bleeding (3.46% versus 2.93%) did not differ significantly. The OPCAB patients did have a statistically significant reduction in the need for intraoperative or postoperative intraaortic balloon pump support (2.31% versus 3.41%; p = 0.023) and in the incidence of postoperative atrial fibrillation (21.21% versus 26.31%; p < 0.001). Adjustment for preoperative risk factors and extent of coronary disease did not substantially change the crude results. Median postoperative length of stay was significantly shorter (5 days versus 6 days, p < 0.001) for OPCAB patients than for CCAB patients.nnnCONCLUSIONSnThis multicenter study showed that patients having OPCAB are not exposed to a greater risk of short-term adverse outcomes. These data also provided evidence that patients having OPCAB have significantly lower need for intraoperative or postoperative intraaortic balloon pump, lower rates of postoperative atrial fibrillation, and a shorter length of stay.

Arterial inflow via an axillary artery graft for the severely atheromatous aorta

BACKGROUNDnStrategy for severe aortic atheromatous disease identified by intraoperative epiaortic ultrasound remains to be determined. We used axillary artery inflow through graft interposition in an attempt to avoid potential embolization.nnnMETHODSnBetween July 1995 and June 1997, axillary artery inflow was used in 29 patients. Procedures performed were coronary artery bypass in 21 patients (3 with combined carotid endarterectomy), aortic valve replacement in 2, valve replacement plus coronary artery bypass in 4, atrial septal defect repair in 1, and arch replacement in 1 patient. Fibrillatory arrest was used in 16 patients and circulatory arrest was used in 16 patients for excision of mobile atheroma or arch reconstruction. Antegrade cerebral perfusion through the axillary artery graft was carried out in 11 patients.nnnRESULTSnThere were no brachial neurovascular complications. Two operative deaths occurred. Two patients had operative strokes and 2 more had postoperative stroke, all with resolution at late follow-up. There were no strokes in the subset of patients who had antegrade cerebral perfusion during circulatory arrest.nnnCONCLUSIONnThe axillary artery is an excellent site for arterial inflow. Furthermore, antegrade cerebral perfusion is easily accomplished during periods of circulatory arrest. Finally, graft placement avoids potential local neurovascular complications.

Long-Term Survival of the Very Elderly Undergoing Aortic Valve Surgery

Background— Increasing numbers of the very elderly are undergoing aortic valve procedures. We describe the short- and long-term survivorship for this cohort. Methods and Results— We conducted a cohort study of 7584 consecutive patients undergoing open aortic valve surgery without (51.1%; AVR) or with (48.9%; AVR + CABG) concomitant coronary artery bypass graft surgery between November 10, 1987 through June 30, 2006. Patient records were linked to the Social Security Administration’s Death Master File. Survivorship was stratified by age and concomitant CABG surgery. During 39 835 person-years of follow-up, there were 2877 deaths. Among AVR, there were 3304 patients <80 years of age, 419 patients 80 to 84 years, and 156 patients ≥85 years (24 patients >90 years). Among AVR+CABG patients, there were 2890 patients <80 years of age, 577 patients 80 to 84 years, and 238 patients ≥85 years (22 patients >90 years). Median survivorship for patients undergoing isolated AVR was 11.5 years (<80 years), 6.8 years (80 to 84 years), 6.2 years (≥85 years); for patients undergoing AVR+CABG, median survivorship was 9.4 years (<80 years), 6.8 years (80 to 84 years), and 7.1 years (≥85 years). Among both procedures, adjusted survivorship was significantly different across strata of age (P<0.001). These findings are similar to life expectancy of the general population from actuarial tables: 80 to 84 years (7 years) and ≥85 years (5 years). Conclusions— Survivorship among octogenarians is favorable, with more than half the patients surviving more than 6 years after their surgery. Concomitant CABG surgery does not diminish median survivorship among patients >80 years of age.

Intra- and postoperative predictors of stroke after coronary artery bypass grafting.

BACKGROUNDnStroke is a devastating complication of coronary artery bypass graft surgery. An individuals risk of stroke is based in part on preoperative characteristics but also on intra- and postoperative factors. We developed a risk prediction model for stroke based on factors in intra- and postoperative care, after adjusting for a patients preoperative risk.nnnMETHODSnWe conducted a regional prospective study of 11,825 consecutive patients undergoing coronary artery bypass graft surgery surgery from 1996 to 2001. Data were collected on patient and disease characteristics, intra- and postoperative care and course, and outcomes. Stroke was defined as a new focal neurologic deficit which appears and is still at least partially evident more than 24 hours after its onset. Logistic regression identified significant predictors of stroke.nnnRESULTSnThe incidence of stroke was 1.5%. The regression model significantly predicted the occurrence of stroke. As compared with cardiopulmonary bypass for less than 90 minutes, cardiopulmonary bypass for 90 to 113 minutes, odds ratio = 1.59, p = 0.022), cardiopulmonary bypass for 114 minutes or more (odds ratio = 2.36, p < 0.001), atrial fibrillation (odds ratio = 1.82, p < 0.001), and prolonged inotrope use (odds ratio = 2.59, p = 0.001) significantly improved our ability to predict stroke. Nearly 75% of all strokes occurred among the 90% of patients at low or medium preoperative risk.nnnCONCLUSIONSnThe inclusion of factors associated with intra- and postoperative care and course significantly improved the prediction model. Most strokes occurred among patients at low or medium preoperative risk, suggesting that many of these strokes may be preventable. Reduction in stroke risk may require modifications in intra- and postoperative care and course.

Long-Term Survival of the Very Elderly Undergoing Coronary Artery Bypass Grafting

BACKGROUNDnIncreasing numbers of the very elderly are undergoing coronary artery bypass graft surgery (CABG). Short-term results have been studied, but few data are available concerning long-term outcomes.nnnMETHODSnWe conducted a cohort study of 54,397 consecutive patients undergoing primary, isolated CABG surgery between July 1, 1987, and June 30, 2006. Patient records were linked to the Social Security Administrations Death Master File.nnnRESULTSnDuring 390,871 person-years of follow-up, there were 17,352 deaths. There were 51,149 patients younger than 80 years, 2,661 patients aged 80 to 84 years, and 587 patients aged 85 or more years who underwent isolated CABG surgery. Crude in-hospital survival was 97.2% for those less than 80 years, 98.3% for those aged 80 to 84 years, and 87.6% for those aged 85 or more years. Patients aged 80 or more years were more likely to be female (46.9%), more likely to be emergency priority (10.2%), and more likely to have associated comorbidities than younger patients. Patients aged 85 or more years were more likely to have intraoperative and postoperative morbid events. Among patients younger than 80, median survival was 14.4 years with an annual incidence of death of 4.2%. Among patients 80 to 84 years old, median survival time was 7.4 years, with an annual incidence rate of death of 10.3%. Among patients aged 85 or more years, median survival was 5.8 years, and the annual incidence of death was 13.7%.nnnCONCLUSIONSnAlthough very elderly CABG patients have more comorbidities and more acute presentation than younger patients and their in-hospital mortality rate is high, their long-term survival is surprisingly good.

Improved in-hospital mortality in women undergoing coronary artery bypass grafting

BACKGROUNDnFew studies have examined the changes in in-hospital mortality for women over time. We describe the changing case mix and mortality for women undergoing coronary artery bypass grafting (CABG) from 1987 to 1997 in northern New England.nnnMETHODSnData were collected on 8,029 women and 21,139 men undergoing isolated CABG. The study consisted of three time periods (1987 to 1989, 1990 to 1992, and 1993 to 1997) to account for regional efforts to improve quality of care that occurred during 1990 to 1992.nnnRESULTSnCompared with 1987 to 1989, women undergoing CABG in 1993 to 1997 were older, had poorer ventricular function, and more often required urgent or emergency operations. The crude and adjusted mortality rates for both women and men decreased significantly over time. The absolute magnitude of the change in adjusted rates was greater for women (3.1%) than for men (1.5%). Although women represented only 28% of the study population, the decrease in their mortality accounted for 44% of the total decrease in adjusted mortality during the study period.nnnCONCLUSIONSnOver the last decade there has been a marked decrease in CABG mortality for women, despite a worsening case mix.

Outcomes of Patients Undergoing Concomitant Aortic and Mitral Valve Surgery in Northern New England

Background— Concomitant aortic (AV) and mitral (MV) valve surgery accounts for 4% of all valve procedures in northern New England. We examined in-hospital and long-term mortality. Methods and Results— This is a report of a prospective study of 1057 patients undergoing concomitant AV and MV surgery from 1989 to 2007. The Social Security Administration Death Master File was used to assess long-term survival. Kaplan–Meier and log-rank tests were performed. In-hospital mortality was 15.5% (11.0% for patients <70 years, 18.0% for 70- to 79-year-olds, and 24% for those ≥80 years). Overall median survival was 7.3 years. Median survival without coronary artery bypass grafting was 9.5 years and with coronary artery bypass grafting was 5.7 years (P<0.001). Survival in women was worse than in men (7.3 versus 9.3, years, P=0.033). Median survival by age was 11.0 years for patients <70 years, 5.4 years for 70- to 79-year-olds, and 4.8 years for those ≥80 years. Median survival was not significantly different for patients ≥80 years compared with those who were 70 to 79 years old (P=0.245). Conclusions— Double-valve surgery has a high in-hospital mortality rate and a median survival of 7.3 years. After patients have survived surgery, long-term survival is similar between men and women, smaller and larger patients, and those receiving MV repair or replacement. Survival continues to decline after surviving surgery for patients ≥70 years old and those who undergo concomitant coronary artery bypass grafting. In patients <70 years, either mechanical valves in both positions or a tissue AV and mitral repair have the lowest in-hospital mortality and the best long-term survival. In patients ≥70 years, tissue valves in both positions have the best in-hospital and long-term survival.

Effect of Preoperative Pulmonary Hypertension on Outcomes in Patients With Severe Aortic Stenosis Following Surgical Aortic Valve Replacement

Pulmonary hypertension (PH) is prevalent in patients with aortic stenosis (AS); however, previous studies have demonstrated inconsistent results regarding the association of PH with adverse outcomes after aortic valve replacement (AVR). The goal of this study was to evaluate the effects of preoperative PH on outcomes after AVR. We performed a regional prospective cohort study using the Northern New England Cardiovascular Disease Study Group database to identify 1,116 consecutive patients from 2005 to 2010 who underwent AVR ± coronary artery bypass grafting for severe AS with a preoperative assessment of pulmonary pressures by right-sided cardiac catheterization. PH was defined as a mean pulmonary artery pressure of ≥25 mm Hg, with severity based on the pulmonary artery systolic pressure-mild, 35 to 44 mm Hg; moderate, 45 to 59 mm Hg; and severe, ≥60 mm Hg. We found that PH was present in 536 patients (48%). Postoperative acute kidney injury, low-output heart failure, and in-hospital mortality increased with worsening severity of PH. In multivariate logistic regression, severe PH was independently associated with postoperative acute kidney injury (adjusted odds ratio 4.1, 95% confidence interval [CI] 1.7 to 10, p = 0.002) and in-hospital mortality (adjusted odds ratio 6.9, 95% CI 2.5 to 19.1, p <0.001). There was a significant association between PH and decreased 5-year survival (adjusted log-rank p value = 0.006), with severe PH being associated with the poorest survival (adjusted hazard ratio 2.4, 95% CI 1.3 to 4.2, p = 0.003). In conclusion, severe PH in patients with severe AS is associated with increased rates of in-hospital adverse events and decreased 5-year survival after AVR.