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Beating heart surgery in octogenarians: perioperative outcome and comparison with younger age groups
Beating Heart Surgery in Octogenarians: Perioperative Outcome and Comparison With Younger Age Groups Sotiris C. Stamou, MD, George Dangas, MD, Mercedes K. C. Dullum, MD, Albert J. Pfister, MD, Steven W. Boyce, MD, Ammar S. Bafi, MD, Jorge M. Garcia, MD, and Paul J. Corso, MD Division of Cardiac Surgery, Department of Surgery, Washington Hospital Center; MedStar Research Institute, Washington, DC
Background. Octogenarians have higher morbidity and mortality rates (9% to 16%) after coronary artery bypass grafting with cardiopulmonary bypass, compared with younger patients. Methods. We compared the perioperative outcome and hospital stay after coronary artery bypass grafting without cardiopulmonary bypass (off-pump) from January 1987 to May 1999, among patients older than 80 years (n ⴝ 71), patients between 70 and 79 years (n ⴝ 228), and patients whose age ranged from 60 to 69 years (n ⴝ 296). In comparison with younger patients, more octogenarians were female (51% versus 39% in patients aged 70 to 79 years and 35% in those aged 60 to 69 years, p ⴝ 0.04), they had previous myocardial infarction more frequently (48% versus 47% versus 34%, respectively, p ⴝ 0.008), and were operated on urgently (69% versus 56% versus 52%, respectively, p ⴝ 0.04). Results. Postoperative complications that were signif-
icantly higher in octogenarians compared with younger groups included pneumonia (6% in octogenarians versus 2% in patients aged 70 to 79 years and 0% in patients aged 60 to 69 years, p ⴝ 0.001) and atrial fibrillation (47% versus 32% versus 21%, respectively, p < 0.001). By multivariate logistic regression analysis, age over 80 years was an independent predictor of prolonged hospital stay (odds ratio ⴝ 2.7, 95% confidence interval, 1.4 to 5, p < 0.001). The in-hospital mortality rate was higher in octogenarians (6% versus 3% for 70 to 79 year-olds and 0.3% for 60 to 69 year-olds, p ⴝ 0.006). Conclusions. When appropriately applied in patients older than 80 years, off-pump coronary artery bypass grafting can be done with acceptable postoperative morbidity, mortality, and hospital stay.
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could result in migration of atheromatous microemboli in the brain during aortic cannulation and thus cause neurologic deterioration shortly after on-pump CABG [11]. In the present study, we compared perioperative morbidity, mortality, and hospital length of stay after offpump CABG in patients older than 80 years with those in younger age groups.
onger life expectancy in patients 80 years old or older [1] has led to increased incidence of cardiovascular disease and a concomitant upsurge in the number of cardiac operations in this age group [2– 4]. Recent studies have demonstrated improved outcomes in terms of morbidity and mortality rates in elderly patients who have coronary artery bypass operations with cardiopulmonary bypass (on-pump), compared with results of a decade ago [5–7]. Improvements in cardiac anesthesia, surgical techniques, and postoperative treatment have contributed significantly to these favorable results [8 –12]. The current trend toward minimally invasive cardiac operations has particular implications for high-risk patients, such as the very elderly. Coronary artery bypass grafting without cardiopulmonary bypass (off-pump CABG) could benefit octogenarians [7]. Lower stroke rates and improved perioperative outcomes have been reported after off-pump CABG compared with on-pump techniques [7]. Moreover, octogenarians are more likely to have atherosclerosis of the ascending aorta, which
Accepted for publication Oct 5, 1999. Address reprint requests to Dr Corso, Washington Hospital Center, 106 Irving St NW, Suite 316 South Tower, Washington, DC 20010; e-mail: [email protected].
© 2000 by The Society of Thoracic Surgeons Published by Elsevier Science Inc
(Ann Thorac Surg 2000;69:1140 –5) © 2000 by The Society of Thoracic Surgeons
Patients and Methods Patients The computerized database of the Division of Cardiac Surgery of the Washington Hospital Center was used to identify all patients who had off-pump CABG between January 1987 and May 1999. During the study period, 993 patients had off-pump CABG. Data from patients 80 years old or older (n ⫽ 71, 7%) were compared with those from patients 70 to 79 years old (n ⫽ 228, 23%) and 60 to 69 years old (n ⫽ 296, 30%). Patients younger than 60 This article has been selected for the open discussion forum on the STS Web site: http://www.sts.org/section/atsdiscussion/
0003-4975/00/$20.00 PII S0003-4975(99)01430-7
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years (n ⫽ 389, 39%) were not included in the study. Baseline demographics, procedural data, and perioperative outcomes were recorded according to prespecified data entry forms. Data were analyzed according to The Society of Thoracic Surgeons National Cardiac Surgery Database guidelines and definitions (www.ctsnet.org/ doc/230). Significant atherosclerosis of the ascending aorta was defined as operator-identified diffuse irregularities, ulcerated plaques, large mobile or protruding atheromata, thrombi, or circumferential involvement of most or all of the ascending aorta were present.
Selection Criteria Indications for off-pump CABG included patients who were considered high risk for on-pump CABG because of medical comorbidities such as renal failure, diffuse cerebrovascular and peripheral vascular disease, aortic atherosclerosis, chronic obstructive pulmonary disease, and religious convictions that precluded blood transfusions. Whenever accuracy or patency of distal anastomosis was in doubt because of fair-sized vessels on the back of the beating heart, on-pump CABG was done.
Surgical Techniques Surgical approaches were median sternotomy or minimally invasive direct coronary artery bypass (MIDCAB) through a left anterior thoracotomy or left posterolateral thoracotomy. Major indications for MIDCAB included isolated disease of the proximal or mid-left anterior descending artery or first diagonal. If more than three vessels were diseased, a median sternotomy approach was favored. Major indications for left posterolateral thoracotomy included stenosis and regrafting of the circumflex arterial system. The three off-pump surgical techniques are briefly described below. MINIMALLY INVASIVE DIRECT CORONARY ARTERY BYPASS. A left anterolateral thoracotomy approach was used. After a 6to 9-cm incision was made, the fourth intercostal space was entered without removing the rib. The costal cartilage was not excised routinely. The left internal mammary artery was harvested under direct vision from the fifth intercostal space to the left subclavian vein, then it was clipped and divided. The pericardium was incised near the internal mammary artery pedicle and parallel to the midline and was suspended by traction sutures. After the diseased artery was located, a silicone elastomer suture bolstered with a pledget encircling the entire artery, epicardial fat, and veins was placed proximally to the anastomotic site to achieve temporary coronary artery occlusion. No ischemic preconditioning was used for myocardial protection. A compression stabilizer (CardioThoracic Systems Inc, Cupertino, CA) was used to stabilize the coronary artery. The anastomosis was done using continuous 7-0 Prolene sutures (Ethicon, Somerville, NJ). A blower device (Aries CO2 Blower, CardioThoracic Systems Inc, Cupertino, CA) was used to keep the field clear of blood and the incised edges of the coronary artery separated during the anastomosis. After the anas-
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tomosis was completed, the internal mammary pedicle was fixed to the epicardium with three 6-0 silk sutures. After a median sternotomy, the left internal mammary artery was harvested using a specialized internal mammary artery access retractor (Rultract; Rultract, Inc, Cleveland, OH). Two or three lap tapes or, alternatively, a glove injected with normal saline via a Foley catheter, was placed beneath the left ventricle to bring the left anterior descending, first diagonal, or ramus marginal artery to the surface and achieve better exposure. Distal anastomoses were done as in the MIDCAB technique using the same compression stabilizer. The inferior and posterolateral arteries were approached using pericardial traction sutures placed anterior to the pulmonary veins and fixed to the drapes on the patient’s left side. Two traction sutures were placed through the acute margin of the right ventricle to approach the right coronary arteries.
MEDIAN STERNOTOMY.
POSTEROLATERAL THORACOTOMY. Single-lung ventilation, lateral decubitus positioning of the patient, and a fifth intercostal space approach were used as appropriate. After retraction of the lung, the pericardium was opened posterior to the phrenic nerve. The radial artery or saphenous vein were used as conduits. The proximal anastomosis was usually placed on the descending thoracic aorta with this approach.
Anesthesia and Intraoperative Monitoring Routine hemodynamic, electrocardiographic, and arterial blood gas monitoring was done during the procedure. Heparin, in a bolus dose of 10,000 IU intravenously, was administered routinely to all patients. Activated clotting time was kept at a range of 300 to 350 seconds. Before the anastomoses were done, lidocaine and magnesium were administered routinely to all patients. Intercostal blocks with bupivacaine were used to achieve pain control after left posterolateral thoracotomy CABG or MIDCAB.
Statistical Analysis Primary comparisons were performed between age groups. Data are expressed as percentages or as mean ⫾ standard deviation. Categoric variables were compared using the two-tailed Pearson 2 test. Continuous variables were compared with two-tailed, one-way analysis of variance for variables with normal distributions and with the two-tailed Kruskal Wallis test for variables with non-normal distributions. A stepwise logistic regression analysis was conducted to define predictors of postoperative stay longer than 7 days (discharge to home). p values of 0.05 or less were considered statistically significant. All statistical analyses were done using the program SPSS 8.0 for Windows 95 (SPSS Inc, Chicago, IL).
Results An increasing number of off-pump CABG procedures were performed in octogenarians during the more recent years of the study period (Fig 1). The preoperative clinical
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Fig 1. Octogenarians who had off-pump versus on-pump coronary artery bypass grafting during the study period (1987 to 1999). There has been an increase in the percentage of octogenarians operated off-pump, over time: from 10% during 1987 to 1989 to 76% during 1996 to 1999. White and black bars represent the percentage of octogenarians operated on-pump and off-pump, respectively.
characteristics of patients in the three age groups are summarized in Table 1. In comparison with the younger age groups, more octogenarians were women (n ⫽ 36, 51%) and they were more likely to have a history of previous myocardial infarction (n ⫽ 34, 48%) and congestive heart failure (n ⫽ 13, 18%). Octogenarians were more likely to have chronic obstructive pulmonary disease (n ⫽ 7, 10%) and more than one diseased vessel (n ⫽ 44, 62%) than younger patients. Finally, octogenarians had a higher frequency of urgent or emergent operations (n ⫽ 49, 69%) than younger patients. Emergent CABG within
24 hours after failed angioplasty was done in 6 patients overall, including 1 octogenarian (1%), 2 septagenarians (1%) and 3 sexagenarians (1%), ( p ⬎ 0.05). Off-pump CABG and transmyocardial revascularization was done in 3 of 595 concurrent patients (0.5%). Significant atherosclerosis of the ascending aorta was identified in 8 octogenarians (11%), 20 septuagenarians (9%), and 8 sexagenarians (3%) ( p ⫽ 0.002). Conduit grafts used in patients with significant atherosclerosis were only arterial (n ⫽ 14, 39%), both arterial and venous (n ⫽ 12, 33%), and only venous (n ⫽ 10, 28%). Complete revascularization was achieved in all patients. Postoperative data are given in Table 2. Mean number of grafts for median sternotomy was 1.6 ⫾ 1.4 compared with 1.0 ⫾ 0.2 for MIDCAB and 1.1 ⫾ 0.3 for left posterolateral thoracotomy ( p ⬍ 0.001). During the course of this study we noted an increase in the number of vessels bypassed with a median sternotomy approach (1.3 ⫾ 0.5 vessels for 1987 to 1996 versus 1.9 ⫾ 1.8 grafts for 1997 to 1999). Median sternotomy has been the preferred approach for more than three vessel CABG (n ⫽ 84). From 1987 to 1995, only 2 patients had more than three vessel bypass in our institution, whereas 82 patients had more than three-vessel off-pump CABG between 1996 and 1999. We preferred MIDCAB mostly in octogenarians, in comparison with the younger age groups, ( p ⫽ 0.02). The octogenarians had slightly higher pulmonary complication and significantly higher postoperative atrial fibrillation rates compared with the other groups.
Table 1. Baseline Clinical Characteristics Characteristic Female gender Age (y) History of myocardial infarction Diabetes Hypertension History of transient ischemic attack History of stroke Chronic renal failure History of COPD Congestive heart failure Ejection fraction ⬍ 0.34 Canadian Cardiological Society class III or IV Preoperative IABP Preoperative nitroglycerine Preoperative inotropic agents Preoperative cardiogenic shock More than one vessel disease Grafted vessels Prior CABG Urgent or emergent CABG
60 – 69 Years (n ⫽ 296)
70 –79 Years (n ⫽ 228)
ⱖ 80 Years (n ⫽ 71)
p Value
102 (34) 65 ⫾ 3 104 (35) 83 (28) 181 (61) 6 (2) 28 (9) 10 (3) 23 (8) 13 (4) 45 (15) 156 (53) 1 (0.3) 19 (6) 1 (0.3) 2 (1) 133 (45) 1⫾1 44 (15) 155 (52)
89 (39) 74 ⫾ 3 108 (47) 60 (26) 159 (70) 5 (2) 28 (12) 3 (1) 21 (9) 16 (7) 63 (21) 130 (57) 2 (1) 23 (10) 1 (0.4) 1 (0.4) 128 (56) 2⫾1 41 (18) 128 (56)
36 (51) 84 ⫾ 3 34 (48) 11 (15) 38 (53) 1 (1) 7 (10) 1 (1) 7 (10) 13 (18) 18 (25) 44 (62) 2 (3) 7 (10) 1 (1) 1 (1) 44 (62) 2⫾1 8 (11) 49 (69)
0.04 ⬍ 0.001 0.008 NS 0.02 NS NS NS 0.05 ⬍ 0.001 0.002 NS NS NS NS NS 0.008 0.001 NS 0.04
Variables are expressed as mean ⫾ standard deviation or n (%). Comparisons were done with Pearson’s 2 or one-way analysis of variance. CABG ⫽ coronary artery bypass graft operation; support; NS ⫽ not significant.
COPD ⫽ chronic obstructive pulmonary disease;
IABP ⫽ intra-aortic balloon pump
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Table 2. Operative and Postoperative Patient Characteristics Characteristic Median sternotomy MIDCAB Thoracotomy Reoperation due to bleeding Q-wave myocardial infarction Mediastinitis Stroke Pulmonary embolism Pulmonary edema Prolonged ventilation Pneumonia Hemodialysis Atrial fibrillation Intraaortic balloon pump Inotropic support Postoperative stay (days) Intensive care unit stay (days) In-hospital death
60 – 69 Years (n ⫽ 296)
70 –79 Years (n ⫽ 228)
ⱖ 80 Years (n ⫽ 71)
p Value
214 (72) 71 (24) 11 (4) 3 (1) 2 (1) 2 (1) 1 (0.3) 2 (1) 4 (1) 3 (1) 0 (0) 1 (0.3) 63 (21) 3 (1) 16 (5) 6⫾5 1.5 ⫾ 2 1 (0.3)
174 (77) 42 (18) 12 (5) 3 (1) 1 (0.4) 1 (0.4) 3 (1) 0 (0) 2 (1) 9 (4) 4 (2) 2 (1) 72 (32) 3 (1) 22 (10) 7⫾7 2⫾3 7 (3)
46 (65) 24 (34) 1 (1) 1 (1) 0 (0) 0 (0) 2 (3) 1 (1) 3 (4) 1 (1) 4 (6) 0 (0) 33 (47) 2 (3) 15 (21) 9⫾6 2⫾2 4 (6)
0.02 0.02 NS NS NS NS NS NS NS 0.07 0.001 NS ⬍ 0.001 NS ⬍ 0.001 0.008 NS 0.006
Variables are expressed as mean ⫾ standard deviation or n (%). MIDCAB ⫽ minimally invasive direct coronary artery bypass;
NS ⫽ not significant.
Postoperative Hospital Stay Postoperative hospital stay was significantly longer in octogenarians, with a rising trend from 60- to 69-yearolds to those age 80 years or older. Univariate correlates of prolonged hospital stay included age 80 years or older, MIDCAB, postoperative atrial fibrillation, postoperative stroke, postoperative prolonged ventilatory support, Canadian Cardiological Society class III or IV, postoperative need for intraaortic balloon pump, more than one vessel disease, congestive heart failure, history of previous stroke, previous myocardial infarction, insulindependent diabetes, and ejection fraction less than 0.34; other significant correlates were preoperative chronic obstructive pulmonary disease ( p ⫽ 0.02) and previous CABG ( p ⫽ 0.01). To investigate whether age over 80 years was an independent predictor of prolonged hospital stay in patients who had off-pump CABG, a multivariate logistic regression analysis was conducted using the factors that were significant in the univariate analysis as independent Table 3. Predictors of Prolonged Postoperative Hospital Stay
Preoperative Age ⱖ 80 years Congestive heart failure Previous stroke Ejection fraction ⬍ 0.34 Postoperative Atrial fibrillation Inotropic support
Odds Ratio
95% Confidence Interval
2.7 2.5 2.2 1.6
1.4 to 5.0 1.1 to 4.3 1.1 to 4.2 1.1 to 2.5
0.002 0.04 0.02 0.04
3.5 6.3
2.2 to 5.2 3.2 to 12
⬍ 0.001 ⬍ 0.001
p Value
variables and postoperative stay more than 7 days as the dependent variable (Table 3). In the multivariate analysis, the preoperative factors of age 80 years or more ( p ⫽ 0.002), congestive heart failure ( p ⫽ 0.04), previous stroke ( p ⫽ 0.02), and ejection fraction less than 0.34 ( p ⫽ 0.04), and the postoperative factors of atrial fibrillation ( p ⬍ 0.001) and need for inotropic support ( p ⬍ 0.001) emerged as independent predictors of prolonged postoperative length of stay.
In-Hospital Mortality The in-hospital mortality rate after off-pump CABG for overall patients included in our study was low (n ⫽ 12, 2%). Despite the low overall mortality rate in patients who had off-pump CABG, we found a statistically significant difference in the hospital mortality rate of octogenarians versus younger patients. The octogenarians had a relatively low mortality rate (6%), although it was higher than that of the 70- to 79-year-old (3%) and 60- to 69-year-old (0.3%) patients. Causes of death for the octogenarians included multiorgan failure (n ⫽ 3) and stroke (n ⫽ 1). Patients in the 70 to 79-year-old age group died of heart failure (n ⫽ 4) and multiorgan failure (n ⫽ 3), and one patient of the 60- to 69-year-olds died of heart failure. (Two deaths occurred in patients younger than 60 years; data not shown.)
Comment Perioperative morbidity and mortality rates increase with increasing age for patients who have CABG with or without cardiopulmonary bypass [12–14]. A rising trend has been documented in the number of octogenarians who have cardiac operations [4, 15]. Less invasive ap-
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Table 4. Published Series of In-Hospital Mortality Rates in Octogenarians Who Had On-Pump Coronary Artery Bypass Grafting Study Mullany et al [22] Weintraub et al [14] Tsai et al [24] Kaul et al [25] Williams et al [26] Morris et al [17] Akins et al [16] Kirsch et al [5] Craver et al [4]
Year Published
Time Frame
Patients (n)
Mortality Rate
1990 1991 1994 1994 1995 1996 1997 1998 1999
1977–1989 1978 –1989 1982–1993 1982–1993 1989 –1994 1987–1994 1985–1995 1991–1996 1976 –1994
159 154 303 205 300 474 292 47 430
11% 10% 8% 6% 11% 8% 6% 13% 8%
proaches have been favored in this subset of patients because of advanced age and associated medical conditions [16 –18]. Off-pump CABG might be a reasonable alternative for octogenarians; however, the risks and outcomes of off-pump CABG in patients older than 80 years have not been clearly defined. During the past 10 years, the number of off-pump CABG operations performed at our institution has increased significantly. A parallel increase in the age of patients who had off-pump procedures has also been documented. We prefer MIDCAB in patients over 80 years of age to reduce operative time and to minimize interventions in geriatric patients. In comparison with the younger patients, octogenarians were more likely to present with congestive heart failure, Canadian Cardiological Society angina class III or IV, ejection fraction lower than 0.34, and more than one vessel coronary artery disease, and they were slightly more likely to present with chronic obstructive pulmonary disease (Table 1). These comorbid conditions increased operative morbidity and mortality, echoing previously reported findings [5, 19, 20]. In addition, a higher percentage of octogenarians were women. Female sex has been recognized as a predictor of operative death [5], partially because of the late referral pattern of women [19] and possibly because of their smaller coronary arteries, which makes myocardial revascularization technically more demanding [5]. However, more recent data suggest that the mortality rate in women is no different than that in men [21]. Moreover, more than two thirds of the octogenarians were operated on an urgent basis, a factor that has a profound effect on perioperative morbidity and mortality rates [9]. Previous studies have reported a high incidence of postoperative complications in octogenarians [13, 22]. Similarly, in our study, octogenarians had a slightly higher rate of pulmonary complications compared with the younger age groups. Additionally, octogenarians more often required postoperative inotropic agents and had a relatively higher in-hospital stroke rate than younger patients, in accordance with a previous report [4]. The postoperative atrial fibrillation rate was significantly higher in the octogenarians, further complicating
their in-hospital outcome, and was an independent predictor of prolonged postoperative stay. Advanced age consistently has been associated with an increase in the risk of atrial fibrillation and is considered a major factor for increased morbidity, mortality, and prolonged hospital stay after CABG [23]. Almassi and associates [23] have reported an 1.6-fold increase in the incidence of postoperative atrial fibrillation for each additional decade of life.
Predictors of Prolonged Postoperative Stay Age 80 years and over emerged as an independent predictor of prolonged postoperative stay in patients who had off-pump CABG. Preoperative congestive heart failure, history of stroke, and ejection fraction less than 0.34 and postoperative inotropic support and new onset atrial fibrillation were also found to prolong postoperative stay. A trend during the study period was the abbreviation of postoperative stay in octogenarians in more recent years. Specifically, for the first 35 octogenarians in our study the median postoperative stay was 8 days (mean, 11 ⫾ 8 days), whereas for the last 36 patients the median postoperative stay was 6 days (mean, 7 ⫾ 4 days). In the current era of reduced health care funds, a shortened hospital stay could favorably affect the relative riskbenefit ratio for cardiac operations, reduce the use of hospital resources, and therefore the cost of care. An interesting trend documented in our study was the increasing percentage of patients receiving one or more internal mammary artery grafts. Use of internal mammary artery grafts has been associated with better shortand long-term outcome [16, 17]. Of the first 35 octogenarians, fewer patients (n ⫽ 14, 40%) received internal mammary artery grafts compared with the last 36 patients (n ⫽ 32, 89%), reflecting a shift in cardiac surgical practice during the past decade.
In-Hospital Mortality Despite the associated comorbid conditions, in-hospital mortality in octogenarians after off-pump CABG was low and comparable to rates reported for octogenarians who had on-pump CABG [4, 5, 16, 17, 22, 24 –26] (Table 4). Further research and comparison between risk-stratified and adjusted populations are needed to compare the two
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techniques and to identify the indications for off-pump versus conventional on-pump CABG in octogenarians.
Limitations The limitations of our study include the drawbacks inherent in any retrospective study, the small number of patients in each group, and the inability to conduct a reliable multivariate analysis to search for predictor variables of early mortality because of the small number of patients with this outcome. Moreover, the short period of clinical follow-up was another limitation, along with the absence of angiographic follow-up, which would document the early and late graft patency in octogenarian patients who had off-pump CABG. Additionally, quality of life and long-term survival after off-pump CABG are important issues that need further investigation. Prospective studies are needed to confirm these results and to investigate the long-term implications of advanced age regarding morbidity and mortality after off-pump CABG.
References 1. Statistical Abstract of the United States: 1991. 11th ed. Washington, DC: US Bureau of the Census, 1991:81. 2. Blanche C, Khan SS, Chaux A, et al. Cardiac reoperations in octogenarians: analysis of outcomes. Ann Thorac Surg 1999; 67:93– 8. 3. Rohrer-Gubler I, Niederhauser U, Turina MI. Late outcome of coronary artery bypass grafting in young versus older patients. Ann Thorac Surg 1998;65:377– 82. 4. Craver JM, Puskas JD, Weintraub WW, et al. 601 octogenarians undergoing cardiac surgery: outcome and comparison with younger age groups. Ann Thorac Surg 1999;67:1104–10. 5. Kirsch M, Guesnier L, LeBesnerais P, et al. Cardiac operations in octogenarians: perioperative risk factors for death and impaired autonomy. Ann Thorac Surg 1998;66:60–7. 6. Katz NM, Hannan RL, Hopkins RA, Wallace RB. Cardiac operations in patients aged 70 years and over: mortality, length of stay, and hospital charge. Ann Thorac Surg 1995; 60:96 –101. 7. BhaskerRao B, VanHimbergen D, Edmonds HL Jr, et al. Evidence for improved cerebral function after minimally invasive bypass surgery. J Cardiac Surg 1998;13:27–31. 8. Cernaianu AC, Vassilidze TV, Flum DR, et al. Predictors of stroke after cardiac surgery. J Cardiac Surg 1995;10:334–9. 9. Gersh BJ, Kronmal RA, Frye RL, et al. Coronary arteriography and coronary artery bypass surgery: morbidity and mortality in patient ages 65 years or older: a report from the Coronary Artery Surgery Study. Circulation 1983;67:483–91.
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10. Horneffer PJ, Gardner TJ, Manolio TA, et al. The effects of age on outcome after coronary bypass surgery. Circulation 1987;76(Suppl V):V6 –12. 11. Freeman WK, Schaff HV, O’Brian PC, et al. Cardiac surgery in the octogenarian: perioperative outcome and clinical follow-up. J Am Coll Cardiol 1991;18:29–35. 12. Edmunds LH Jr, Stephenson LW, Edie RN, Ratcliffe MB. Open heart surgery in octogenarians. N Engl J Med 1988;319: 131– 6. 13. Stason WB, Sanders CA, Smith HC. Cardiovascular care of the elderly: economic considerations. J Am Coll Cardiol 1987;10:18A–21A. 14. Weintraub WS, Craver JM, Cohen C, Jones EL, Guyton RA. Influence of age on results of coronary artery surgery. Circulation 1991;84(Suppl 3):226–35. 15. Cane ME, Chen C, Bailey BM, et al. CABG in octogenarians: early and late events and actuarial survival in comparison with a matched population. Ann Thorac Surg 1995;60:1033–7. 16. Akins CW, Daggett WM, Vlahakes GJ, et al. Cardiac operations in patients 80 years old and older. Ann Thorac Surg 1997;64:606–15. 17. Morris RJ, Strong MD, Grunewald KE, et al. Internal thoracic artery for coronary artery grafting in octogenarians. Ann Thorac Surg 1996;62:16–22. 18. Peterson ED, Cowper PA, Jollis JG, et al. Outcomes of coronary artery bypass graft surgery in 24,461 patients aged 80 years or older. Circulation 1995;92(Suppl 2):85–91. 19. Khan SS, Nessim S, Gray R, Czer LS, Chaux A, Matloff J. Increased mortality of women in coronary artery bypass surgery: evidence for referral bias. Ann Intern Med 1990;112: 561–7. 20. Rich MW, Sandza JG, Kleiger RE, Connors JP. Cardiac operations in patients over 80 years of age. J Thorac Cardiovasc Surg 1985;90:56– 60. 21. Jacobs AK, Kelsey SF, Brooks DM, et al. Better outcome of women compared with men undergoing coronary revascularization: a report from the Bypass Angioplasty Revascularization Investigation (BARI). Circulation 1998;98:1279– 85. 22. Mullany CJ, Darling GE, Pluth JR, et al. Early and late results after isolated coronary artery bypass surgery in 159 patients aged 80 years and older. Circulation 1990;82(Suppl 4):229–36. 23. Almassi GH, Schowalter T, Nicolosi AC, et al. Atrial fibrillation after cardiac surgery: a major morbid event? Ann Surg 1997;226:501–13. 24. Tsai TP, Chaux A, Matloff JM, et al. Ten year experience of cardiac surgery in patients aged 80 years and over. Ann Thorac Surg 1994;58:445–51. 25. Kaul TK, Fields BL, Wyatt DA, Jones CR, Kahn DR. Angioplasty versus coronary artery bypass in octogenarians. Ann Thorac Surg 1994;58:1419–26. 26. Williams DB, Carillo RJ, Traad EA. Determinants of operative mortality in octogenarians undergoing coronary bypass. Ann Thorac Surg 1995;60:1038– 43.
Background. Octogenarians have higher morbidity and mortality rates (9% to 16%) after coronary artery bypass grafting with cardiopulmonary bypass, compared with younger patients. Methods. We compared the perioperative outcome and hospital stay after coronary artery bypass grafting without cardiopulmonary bypass (off-pump) from January 1987 to May 1999, among patients older than 80 years (n ⴝ 71), patients between 70 and 79 years (n ⴝ 228), and patients whose age ranged from 60 to 69 years (n ⴝ 296). In comparison with younger patients, more octogenarians were female (51% versus 39% in patients aged 70 to 79 years and 35% in those aged 60 to 69 years, p ⴝ 0.04), they had previous myocardial infarction more frequently (48% versus 47% versus 34%, respectively, p ⴝ 0.008), and were operated on urgently (69% versus 56% versus 52%, respectively, p ⴝ 0.04). Results. Postoperative complications that were signif-
icantly higher in octogenarians compared with younger groups included pneumonia (6% in octogenarians versus 2% in patients aged 70 to 79 years and 0% in patients aged 60 to 69 years, p ⴝ 0.001) and atrial fibrillation (47% versus 32% versus 21%, respectively, p < 0.001). By multivariate logistic regression analysis, age over 80 years was an independent predictor of prolonged hospital stay (odds ratio ⴝ 2.7, 95% confidence interval, 1.4 to 5, p < 0.001). The in-hospital mortality rate was higher in octogenarians (6% versus 3% for 70 to 79 year-olds and 0.3% for 60 to 69 year-olds, p ⴝ 0.006). Conclusions. When appropriately applied in patients older than 80 years, off-pump coronary artery bypass grafting can be done with acceptable postoperative morbidity, mortality, and hospital stay.
L
could result in migration of atheromatous microemboli in the brain during aortic cannulation and thus cause neurologic deterioration shortly after on-pump CABG [11]. In the present study, we compared perioperative morbidity, mortality, and hospital length of stay after offpump CABG in patients older than 80 years with those in younger age groups.
onger life expectancy in patients 80 years old or older [1] has led to increased incidence of cardiovascular disease and a concomitant upsurge in the number of cardiac operations in this age group [2– 4]. Recent studies have demonstrated improved outcomes in terms of morbidity and mortality rates in elderly patients who have coronary artery bypass operations with cardiopulmonary bypass (on-pump), compared with results of a decade ago [5–7]. Improvements in cardiac anesthesia, surgical techniques, and postoperative treatment have contributed significantly to these favorable results [8 –12]. The current trend toward minimally invasive cardiac operations has particular implications for high-risk patients, such as the very elderly. Coronary artery bypass grafting without cardiopulmonary bypass (off-pump CABG) could benefit octogenarians [7]. Lower stroke rates and improved perioperative outcomes have been reported after off-pump CABG compared with on-pump techniques [7]. Moreover, octogenarians are more likely to have atherosclerosis of the ascending aorta, which
Accepted for publication Oct 5, 1999. Address reprint requests to Dr Corso, Washington Hospital Center, 106 Irving St NW, Suite 316 South Tower, Washington, DC 20010; e-mail: [email protected].
© 2000 by The Society of Thoracic Surgeons Published by Elsevier Science Inc
(Ann Thorac Surg 2000;69:1140 –5) © 2000 by The Society of Thoracic Surgeons
Patients and Methods Patients The computerized database of the Division of Cardiac Surgery of the Washington Hospital Center was used to identify all patients who had off-pump CABG between January 1987 and May 1999. During the study period, 993 patients had off-pump CABG. Data from patients 80 years old or older (n ⫽ 71, 7%) were compared with those from patients 70 to 79 years old (n ⫽ 228, 23%) and 60 to 69 years old (n ⫽ 296, 30%). Patients younger than 60 This article has been selected for the open discussion forum on the STS Web site: http://www.sts.org/section/atsdiscussion/
0003-4975/00/$20.00 PII S0003-4975(99)01430-7
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years (n ⫽ 389, 39%) were not included in the study. Baseline demographics, procedural data, and perioperative outcomes were recorded according to prespecified data entry forms. Data were analyzed according to The Society of Thoracic Surgeons National Cardiac Surgery Database guidelines and definitions (www.ctsnet.org/ doc/230). Significant atherosclerosis of the ascending aorta was defined as operator-identified diffuse irregularities, ulcerated plaques, large mobile or protruding atheromata, thrombi, or circumferential involvement of most or all of the ascending aorta were present.
Selection Criteria Indications for off-pump CABG included patients who were considered high risk for on-pump CABG because of medical comorbidities such as renal failure, diffuse cerebrovascular and peripheral vascular disease, aortic atherosclerosis, chronic obstructive pulmonary disease, and religious convictions that precluded blood transfusions. Whenever accuracy or patency of distal anastomosis was in doubt because of fair-sized vessels on the back of the beating heart, on-pump CABG was done.
Surgical Techniques Surgical approaches were median sternotomy or minimally invasive direct coronary artery bypass (MIDCAB) through a left anterior thoracotomy or left posterolateral thoracotomy. Major indications for MIDCAB included isolated disease of the proximal or mid-left anterior descending artery or first diagonal. If more than three vessels were diseased, a median sternotomy approach was favored. Major indications for left posterolateral thoracotomy included stenosis and regrafting of the circumflex arterial system. The three off-pump surgical techniques are briefly described below. MINIMALLY INVASIVE DIRECT CORONARY ARTERY BYPASS. A left anterolateral thoracotomy approach was used. After a 6to 9-cm incision was made, the fourth intercostal space was entered without removing the rib. The costal cartilage was not excised routinely. The left internal mammary artery was harvested under direct vision from the fifth intercostal space to the left subclavian vein, then it was clipped and divided. The pericardium was incised near the internal mammary artery pedicle and parallel to the midline and was suspended by traction sutures. After the diseased artery was located, a silicone elastomer suture bolstered with a pledget encircling the entire artery, epicardial fat, and veins was placed proximally to the anastomotic site to achieve temporary coronary artery occlusion. No ischemic preconditioning was used for myocardial protection. A compression stabilizer (CardioThoracic Systems Inc, Cupertino, CA) was used to stabilize the coronary artery. The anastomosis was done using continuous 7-0 Prolene sutures (Ethicon, Somerville, NJ). A blower device (Aries CO2 Blower, CardioThoracic Systems Inc, Cupertino, CA) was used to keep the field clear of blood and the incised edges of the coronary artery separated during the anastomosis. After the anas-
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tomosis was completed, the internal mammary pedicle was fixed to the epicardium with three 6-0 silk sutures. After a median sternotomy, the left internal mammary artery was harvested using a specialized internal mammary artery access retractor (Rultract; Rultract, Inc, Cleveland, OH). Two or three lap tapes or, alternatively, a glove injected with normal saline via a Foley catheter, was placed beneath the left ventricle to bring the left anterior descending, first diagonal, or ramus marginal artery to the surface and achieve better exposure. Distal anastomoses were done as in the MIDCAB technique using the same compression stabilizer. The inferior and posterolateral arteries were approached using pericardial traction sutures placed anterior to the pulmonary veins and fixed to the drapes on the patient’s left side. Two traction sutures were placed through the acute margin of the right ventricle to approach the right coronary arteries.
MEDIAN STERNOTOMY.
POSTEROLATERAL THORACOTOMY. Single-lung ventilation, lateral decubitus positioning of the patient, and a fifth intercostal space approach were used as appropriate. After retraction of the lung, the pericardium was opened posterior to the phrenic nerve. The radial artery or saphenous vein were used as conduits. The proximal anastomosis was usually placed on the descending thoracic aorta with this approach.
Anesthesia and Intraoperative Monitoring Routine hemodynamic, electrocardiographic, and arterial blood gas monitoring was done during the procedure. Heparin, in a bolus dose of 10,000 IU intravenously, was administered routinely to all patients. Activated clotting time was kept at a range of 300 to 350 seconds. Before the anastomoses were done, lidocaine and magnesium were administered routinely to all patients. Intercostal blocks with bupivacaine were used to achieve pain control after left posterolateral thoracotomy CABG or MIDCAB.
Statistical Analysis Primary comparisons were performed between age groups. Data are expressed as percentages or as mean ⫾ standard deviation. Categoric variables were compared using the two-tailed Pearson 2 test. Continuous variables were compared with two-tailed, one-way analysis of variance for variables with normal distributions and with the two-tailed Kruskal Wallis test for variables with non-normal distributions. A stepwise logistic regression analysis was conducted to define predictors of postoperative stay longer than 7 days (discharge to home). p values of 0.05 or less were considered statistically significant. All statistical analyses were done using the program SPSS 8.0 for Windows 95 (SPSS Inc, Chicago, IL).
Results An increasing number of off-pump CABG procedures were performed in octogenarians during the more recent years of the study period (Fig 1). The preoperative clinical
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Fig 1. Octogenarians who had off-pump versus on-pump coronary artery bypass grafting during the study period (1987 to 1999). There has been an increase in the percentage of octogenarians operated off-pump, over time: from 10% during 1987 to 1989 to 76% during 1996 to 1999. White and black bars represent the percentage of octogenarians operated on-pump and off-pump, respectively.
characteristics of patients in the three age groups are summarized in Table 1. In comparison with the younger age groups, more octogenarians were women (n ⫽ 36, 51%) and they were more likely to have a history of previous myocardial infarction (n ⫽ 34, 48%) and congestive heart failure (n ⫽ 13, 18%). Octogenarians were more likely to have chronic obstructive pulmonary disease (n ⫽ 7, 10%) and more than one diseased vessel (n ⫽ 44, 62%) than younger patients. Finally, octogenarians had a higher frequency of urgent or emergent operations (n ⫽ 49, 69%) than younger patients. Emergent CABG within
24 hours after failed angioplasty was done in 6 patients overall, including 1 octogenarian (1%), 2 septagenarians (1%) and 3 sexagenarians (1%), ( p ⬎ 0.05). Off-pump CABG and transmyocardial revascularization was done in 3 of 595 concurrent patients (0.5%). Significant atherosclerosis of the ascending aorta was identified in 8 octogenarians (11%), 20 septuagenarians (9%), and 8 sexagenarians (3%) ( p ⫽ 0.002). Conduit grafts used in patients with significant atherosclerosis were only arterial (n ⫽ 14, 39%), both arterial and venous (n ⫽ 12, 33%), and only venous (n ⫽ 10, 28%). Complete revascularization was achieved in all patients. Postoperative data are given in Table 2. Mean number of grafts for median sternotomy was 1.6 ⫾ 1.4 compared with 1.0 ⫾ 0.2 for MIDCAB and 1.1 ⫾ 0.3 for left posterolateral thoracotomy ( p ⬍ 0.001). During the course of this study we noted an increase in the number of vessels bypassed with a median sternotomy approach (1.3 ⫾ 0.5 vessels for 1987 to 1996 versus 1.9 ⫾ 1.8 grafts for 1997 to 1999). Median sternotomy has been the preferred approach for more than three vessel CABG (n ⫽ 84). From 1987 to 1995, only 2 patients had more than three vessel bypass in our institution, whereas 82 patients had more than three-vessel off-pump CABG between 1996 and 1999. We preferred MIDCAB mostly in octogenarians, in comparison with the younger age groups, ( p ⫽ 0.02). The octogenarians had slightly higher pulmonary complication and significantly higher postoperative atrial fibrillation rates compared with the other groups.
Table 1. Baseline Clinical Characteristics Characteristic Female gender Age (y) History of myocardial infarction Diabetes Hypertension History of transient ischemic attack History of stroke Chronic renal failure History of COPD Congestive heart failure Ejection fraction ⬍ 0.34 Canadian Cardiological Society class III or IV Preoperative IABP Preoperative nitroglycerine Preoperative inotropic agents Preoperative cardiogenic shock More than one vessel disease Grafted vessels Prior CABG Urgent or emergent CABG
60 – 69 Years (n ⫽ 296)
70 –79 Years (n ⫽ 228)
ⱖ 80 Years (n ⫽ 71)
p Value
102 (34) 65 ⫾ 3 104 (35) 83 (28) 181 (61) 6 (2) 28 (9) 10 (3) 23 (8) 13 (4) 45 (15) 156 (53) 1 (0.3) 19 (6) 1 (0.3) 2 (1) 133 (45) 1⫾1 44 (15) 155 (52)
89 (39) 74 ⫾ 3 108 (47) 60 (26) 159 (70) 5 (2) 28 (12) 3 (1) 21 (9) 16 (7) 63 (21) 130 (57) 2 (1) 23 (10) 1 (0.4) 1 (0.4) 128 (56) 2⫾1 41 (18) 128 (56)
36 (51) 84 ⫾ 3 34 (48) 11 (15) 38 (53) 1 (1) 7 (10) 1 (1) 7 (10) 13 (18) 18 (25) 44 (62) 2 (3) 7 (10) 1 (1) 1 (1) 44 (62) 2⫾1 8 (11) 49 (69)
0.04 ⬍ 0.001 0.008 NS 0.02 NS NS NS 0.05 ⬍ 0.001 0.002 NS NS NS NS NS 0.008 0.001 NS 0.04
Variables are expressed as mean ⫾ standard deviation or n (%). Comparisons were done with Pearson’s 2 or one-way analysis of variance. CABG ⫽ coronary artery bypass graft operation; support; NS ⫽ not significant.
COPD ⫽ chronic obstructive pulmonary disease;
IABP ⫽ intra-aortic balloon pump
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Table 2. Operative and Postoperative Patient Characteristics Characteristic Median sternotomy MIDCAB Thoracotomy Reoperation due to bleeding Q-wave myocardial infarction Mediastinitis Stroke Pulmonary embolism Pulmonary edema Prolonged ventilation Pneumonia Hemodialysis Atrial fibrillation Intraaortic balloon pump Inotropic support Postoperative stay (days) Intensive care unit stay (days) In-hospital death
60 – 69 Years (n ⫽ 296)
70 –79 Years (n ⫽ 228)
ⱖ 80 Years (n ⫽ 71)
p Value
214 (72) 71 (24) 11 (4) 3 (1) 2 (1) 2 (1) 1 (0.3) 2 (1) 4 (1) 3 (1) 0 (0) 1 (0.3) 63 (21) 3 (1) 16 (5) 6⫾5 1.5 ⫾ 2 1 (0.3)
174 (77) 42 (18) 12 (5) 3 (1) 1 (0.4) 1 (0.4) 3 (1) 0 (0) 2 (1) 9 (4) 4 (2) 2 (1) 72 (32) 3 (1) 22 (10) 7⫾7 2⫾3 7 (3)
46 (65) 24 (34) 1 (1) 1 (1) 0 (0) 0 (0) 2 (3) 1 (1) 3 (4) 1 (1) 4 (6) 0 (0) 33 (47) 2 (3) 15 (21) 9⫾6 2⫾2 4 (6)
0.02 0.02 NS NS NS NS NS NS NS 0.07 0.001 NS ⬍ 0.001 NS ⬍ 0.001 0.008 NS 0.006
Variables are expressed as mean ⫾ standard deviation or n (%). MIDCAB ⫽ minimally invasive direct coronary artery bypass;
NS ⫽ not significant.
Postoperative Hospital Stay Postoperative hospital stay was significantly longer in octogenarians, with a rising trend from 60- to 69-yearolds to those age 80 years or older. Univariate correlates of prolonged hospital stay included age 80 years or older, MIDCAB, postoperative atrial fibrillation, postoperative stroke, postoperative prolonged ventilatory support, Canadian Cardiological Society class III or IV, postoperative need for intraaortic balloon pump, more than one vessel disease, congestive heart failure, history of previous stroke, previous myocardial infarction, insulindependent diabetes, and ejection fraction less than 0.34; other significant correlates were preoperative chronic obstructive pulmonary disease ( p ⫽ 0.02) and previous CABG ( p ⫽ 0.01). To investigate whether age over 80 years was an independent predictor of prolonged hospital stay in patients who had off-pump CABG, a multivariate logistic regression analysis was conducted using the factors that were significant in the univariate analysis as independent Table 3. Predictors of Prolonged Postoperative Hospital Stay
Preoperative Age ⱖ 80 years Congestive heart failure Previous stroke Ejection fraction ⬍ 0.34 Postoperative Atrial fibrillation Inotropic support
Odds Ratio
95% Confidence Interval
2.7 2.5 2.2 1.6
1.4 to 5.0 1.1 to 4.3 1.1 to 4.2 1.1 to 2.5
0.002 0.04 0.02 0.04
3.5 6.3
2.2 to 5.2 3.2 to 12
⬍ 0.001 ⬍ 0.001
p Value
variables and postoperative stay more than 7 days as the dependent variable (Table 3). In the multivariate analysis, the preoperative factors of age 80 years or more ( p ⫽ 0.002), congestive heart failure ( p ⫽ 0.04), previous stroke ( p ⫽ 0.02), and ejection fraction less than 0.34 ( p ⫽ 0.04), and the postoperative factors of atrial fibrillation ( p ⬍ 0.001) and need for inotropic support ( p ⬍ 0.001) emerged as independent predictors of prolonged postoperative length of stay.
In-Hospital Mortality The in-hospital mortality rate after off-pump CABG for overall patients included in our study was low (n ⫽ 12, 2%). Despite the low overall mortality rate in patients who had off-pump CABG, we found a statistically significant difference in the hospital mortality rate of octogenarians versus younger patients. The octogenarians had a relatively low mortality rate (6%), although it was higher than that of the 70- to 79-year-old (3%) and 60- to 69-year-old (0.3%) patients. Causes of death for the octogenarians included multiorgan failure (n ⫽ 3) and stroke (n ⫽ 1). Patients in the 70 to 79-year-old age group died of heart failure (n ⫽ 4) and multiorgan failure (n ⫽ 3), and one patient of the 60- to 69-year-olds died of heart failure. (Two deaths occurred in patients younger than 60 years; data not shown.)
Comment Perioperative morbidity and mortality rates increase with increasing age for patients who have CABG with or without cardiopulmonary bypass [12–14]. A rising trend has been documented in the number of octogenarians who have cardiac operations [4, 15]. Less invasive ap-
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Table 4. Published Series of In-Hospital Mortality Rates in Octogenarians Who Had On-Pump Coronary Artery Bypass Grafting Study Mullany et al [22] Weintraub et al [14] Tsai et al [24] Kaul et al [25] Williams et al [26] Morris et al [17] Akins et al [16] Kirsch et al [5] Craver et al [4]
Year Published
Time Frame
Patients (n)
Mortality Rate
1990 1991 1994 1994 1995 1996 1997 1998 1999
1977–1989 1978 –1989 1982–1993 1982–1993 1989 –1994 1987–1994 1985–1995 1991–1996 1976 –1994
159 154 303 205 300 474 292 47 430
11% 10% 8% 6% 11% 8% 6% 13% 8%
proaches have been favored in this subset of patients because of advanced age and associated medical conditions [16 –18]. Off-pump CABG might be a reasonable alternative for octogenarians; however, the risks and outcomes of off-pump CABG in patients older than 80 years have not been clearly defined. During the past 10 years, the number of off-pump CABG operations performed at our institution has increased significantly. A parallel increase in the age of patients who had off-pump procedures has also been documented. We prefer MIDCAB in patients over 80 years of age to reduce operative time and to minimize interventions in geriatric patients. In comparison with the younger patients, octogenarians were more likely to present with congestive heart failure, Canadian Cardiological Society angina class III or IV, ejection fraction lower than 0.34, and more than one vessel coronary artery disease, and they were slightly more likely to present with chronic obstructive pulmonary disease (Table 1). These comorbid conditions increased operative morbidity and mortality, echoing previously reported findings [5, 19, 20]. In addition, a higher percentage of octogenarians were women. Female sex has been recognized as a predictor of operative death [5], partially because of the late referral pattern of women [19] and possibly because of their smaller coronary arteries, which makes myocardial revascularization technically more demanding [5]. However, more recent data suggest that the mortality rate in women is no different than that in men [21]. Moreover, more than two thirds of the octogenarians were operated on an urgent basis, a factor that has a profound effect on perioperative morbidity and mortality rates [9]. Previous studies have reported a high incidence of postoperative complications in octogenarians [13, 22]. Similarly, in our study, octogenarians had a slightly higher rate of pulmonary complications compared with the younger age groups. Additionally, octogenarians more often required postoperative inotropic agents and had a relatively higher in-hospital stroke rate than younger patients, in accordance with a previous report [4]. The postoperative atrial fibrillation rate was significantly higher in the octogenarians, further complicating
their in-hospital outcome, and was an independent predictor of prolonged postoperative stay. Advanced age consistently has been associated with an increase in the risk of atrial fibrillation and is considered a major factor for increased morbidity, mortality, and prolonged hospital stay after CABG [23]. Almassi and associates [23] have reported an 1.6-fold increase in the incidence of postoperative atrial fibrillation for each additional decade of life.
Predictors of Prolonged Postoperative Stay Age 80 years and over emerged as an independent predictor of prolonged postoperative stay in patients who had off-pump CABG. Preoperative congestive heart failure, history of stroke, and ejection fraction less than 0.34 and postoperative inotropic support and new onset atrial fibrillation were also found to prolong postoperative stay. A trend during the study period was the abbreviation of postoperative stay in octogenarians in more recent years. Specifically, for the first 35 octogenarians in our study the median postoperative stay was 8 days (mean, 11 ⫾ 8 days), whereas for the last 36 patients the median postoperative stay was 6 days (mean, 7 ⫾ 4 days). In the current era of reduced health care funds, a shortened hospital stay could favorably affect the relative riskbenefit ratio for cardiac operations, reduce the use of hospital resources, and therefore the cost of care. An interesting trend documented in our study was the increasing percentage of patients receiving one or more internal mammary artery grafts. Use of internal mammary artery grafts has been associated with better shortand long-term outcome [16, 17]. Of the first 35 octogenarians, fewer patients (n ⫽ 14, 40%) received internal mammary artery grafts compared with the last 36 patients (n ⫽ 32, 89%), reflecting a shift in cardiac surgical practice during the past decade.
In-Hospital Mortality Despite the associated comorbid conditions, in-hospital mortality in octogenarians after off-pump CABG was low and comparable to rates reported for octogenarians who had on-pump CABG [4, 5, 16, 17, 22, 24 –26] (Table 4). Further research and comparison between risk-stratified and adjusted populations are needed to compare the two
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techniques and to identify the indications for off-pump versus conventional on-pump CABG in octogenarians.
Limitations The limitations of our study include the drawbacks inherent in any retrospective study, the small number of patients in each group, and the inability to conduct a reliable multivariate analysis to search for predictor variables of early mortality because of the small number of patients with this outcome. Moreover, the short period of clinical follow-up was another limitation, along with the absence of angiographic follow-up, which would document the early and late graft patency in octogenarian patients who had off-pump CABG. Additionally, quality of life and long-term survival after off-pump CABG are important issues that need further investigation. Prospective studies are needed to confirm these results and to investigate the long-term implications of advanced age regarding morbidity and mortality after off-pump CABG.
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