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Comparison of Results of Coronary Artery Bypass Grafting Versus Percutaneous Coronary Intervention in Octogenarians

      The aim of the present study was to compare the outcomes after coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) in patients aged ≥80 years. The present analysis included 274 patients who underwent isolated CABG and 393 patients who underwent PCI. The patients undergoing PCI had a greater prevalence of a history of cardiac surgery and recent myocardial infarction and had more frequently undergone emergency revascularization. Patients undergoing CABG had a significantly greater prevalence of 3-vessel coronary artery disease. The unadjusted 30-day mortality rate was 8.8% after CABG and 7.4% after PCI (p = 0.514). However, on multivariate analysis, CABG was associated with a significantly increased risk of 30-day mortality (odds ratio 2.246, 95% confidence interval 1.141 to 4.422). The unadjusted overall intermediate survival was significantly poorer after PCI (at 5 years, CABG 72.2% vs PCI 59.5%, p = 0.004), but this was not confirmed on multivariate analysis. PCI and CABG had similar intermediate survival rates when adjusted for propensity score (p = 0.698), a finding confirmed by the analysis of 130 propensity score-matched pairs (at 5 years, CABG 66.4% vs PCI 58.9%, p = 0.730). In conclusion, the survival of patients aged ≥80 years undergoing CABG is excellent, and the suboptimal survival after PCI seems to be related to the disproportionately greater risk of these patients compared to those undergoing CABG. When adjusted for important clinical variables, PCI and CABG achieved similar intermediate results.
      Data from the United Nations have indicated that by 2050 the >80-year age group is projected to reach 379 million worldwide, about 5.5 times as many in 2000, when there were 69 million persons aged ≥80 years. Coronary revascularization procedures are becoming more common in this age group with the increasing numbers of persons aged ≥80 years, as well as because of the favorable outcomes of octogenarians after coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI).
      • McKellar S.H.
      • Brown M.L.
      • Frye R.L.
      • Schaff H.V.
      • Sundt III, T.M.
      Comparison of coronary revascularization procedures in octogenarians: a systematic review and meta-analysis.
      The use of PCI in these high-risk patients is attractive because of its minimally invasive nature and its somewhat lower operative mortality.
      • McKellar S.H.
      • Brown M.L.
      • Frye R.L.
      • Schaff H.V.
      • Sundt III, T.M.
      Comparison of coronary revascularization procedures in octogenarians: a systematic review and meta-analysis.
      However, CABG has been shown to achieve excellent intermediate survival.
      • Vasques F.
      • Rainio A.
      • Heikkinen J.
      • Mikkola R.
      • Lahtinen J.
      • Kettunen U.
      • Juvonen T.
      • Biancari F.
      Off-pump versus on-pump coronary artery bypass surgery in patients aged 80 years and older: institutional results and meta-analysis.
      • Nissinen J.
      • Wistbacka J.O.
      • Loponen P.
      • Korpilahti K.
      • Teittinen K.
      • Virkkilä M.
      • Tarkka M.
      • Biancari F.
      Coronary artery bypass surgery in octogenarians: long-term outcome can be better than expected.
      Whether PCI is superior to CABG in patients aged ≥80 years is largely unknown, and we investigated this issue in the present study.

      Methods

      The present study included a consecutive series of 274 patients who underwent isolated CABG at the Oulu University Hospital and Turku University Hospital, Finland, from January 2001 to January 2011 and 393 consecutive patients who underwent PCI at the Turku University Hospital, Finland, from January 2002 to January 2011. All the patients were aged ≥80 years. The ethics committee of our institutions approved the study protocol. Data on the cause and date of death for all patients were retrieved from the Finnish National Registry Statistics Finland. The mean follow-up was 3.6 ± 2.6 years. The cause of late death was unknown for 9 patients (2.3%) who had undergone PCI and for 7 patients (2.6%) who had undergone CABG, and these were considered noncardiac deaths for the present analysis. The main outcome end points of the study were cardiac and all-cause mortality.
      Statistical analysis was performed using PASW, version 18 (IBM SPSS, Chicago, Illinois). Fisher's exact test, the Mann-Whitney U test, and the Kaplan-Meier test were used for univariate analysis. Multivariate analysis was performed using logistic and Cox regression analyses with backward selection by including variables with p <0.05 on univariate analysis. The treatment groups differed with respect to the pretreatment covariables. Therefore, the propensity score was calculated by logistic regression analysis with backward selection by including the clinical variables with p <0.20 on univariate analysis. This was used for 1-to-1 matching and for adjustment of the risk in the overall series. One-to-one propensity score matching between the study groups was done with a caliber width (0.06) estimated according to Austin.
      • Austin P.C.
      Optimal caliper widths for propensity-score matching when estimating differences in means and differences in proportions in observational studies.
      p Values <0.050 were considered statistically significant.

      Results

      The patients undergoing PCI were significantly older and more frequently had a history of cardiac surgery, had had a recent myocardial infarction, and had required emergency revascularization (Table 1). Patients undergoing CABG had a significantly greater prevalence of 3-vessel coronary artery disease (Table 1).
      Table 1Baseline characteristics, operative data, and survival of patients aged ≥80 years
      VariableOverall SeriesPropensity Score-Matched Pairs
      CABG Group (n = 273)PCI Group (n = 392)p ValueCABG Group (n = 130)PCI Group (n = 130)p Value
      Age (years)82.0 ± 1.783.3 ± 2.5<0.000182.5 ± 2.082.6 ± 2.10.808
      Women107 (39%)193 (49%)0.01048 (37%)59 (45%)0.166
      Serum creatinine (mg/dl)89 ± 2494 ± 520.50890 ± 25102 ± 710.178
      Pulmonary disease34 (13%)39 (10%)0.27113 (10%)16 (12%)0.555
      Extracardiac arteriopathy28 (10%)31 (8%)0.27520 (15%)12 (9%)0.131
      Diabetes mellitus47 (18%)88 (22%)0.12433 (25%)25 (19%)0.233
      Hypertension182 (68%)273 (70%)0.58892 (71%)92 (71%)1.000
      Stroke15 (6%)25 (6%)0.66310 (8%)12 (9%)0.656
      Neurologic dysfunction9 (3%)5 (1%)0.1006 (5%)1 (1%)0.120
      Previous percutaneous coronary intervention23 (9%)42 (11%)0.36716 (12%)13 (10%)0.541
      Previous cardiac surgery4 (2%)31 (8%)<0.00014 (3%)3 (2%)1.000
      Coronary arteries narrowed (n)<0.00010.488
       15 (2%)83 (21%)5 (4%)3 (2%)
       230 (11%)170 (43%)27 (21%)34 (26%)
       3238 (87%)139 (36%)98 (75%)93 (72%)
      Left main stenosis118 (43%)119 (43%)0.96156 (43%)48 (51%)0.268
      Left ventricular ejection fraction ≤50%72 (26%)105 (27%)0.90645 (35%)32 (25%)0.077
      Myocardial infarction <3 mo154 (56%)303 (77%)<0.000191 (70%)84 (65%)0.355
      Emergency procedure26 (10%)125 (32%)<0.000123 (18%)24 (19%)0.872
      Beating heart surgery106 (39%)3 (4%)
      ≥1 Mammary artery graft224 (82%)99 (76%)
      No. distal anastomoses3.3 ± 1.03.1 ± 1.1
      Vessels treated by percutaneous coronary intervention1.2 ± 0.41.2 ± 0.5
      Drug-eluting stents (n)106 (27%)35 (27%)
      Short and intermediate overall survival0.0040.730
       30 day91.2%92.6%89.2%92.3%
       1 year87.5%86.0%83.1%86.2%
       3 years80.4%71.6%71.3%69.7%
       5 years72.2%59.5%66.4%58.9%
      Continuous variable are reported as mean ± SD.
      Definition criteria were according to the European System for Cardiac Operative Risk Evaluation criteria.
      The 30-day mortality rate was 8.8% after CABG and 7.4% after PCI (p = 0.514). Diabetes (p = 0.018), an emergency procedure (p <0.0001), and serum creatinine (p <0.0001) were independent predictors of 30-day mortality on logistic regression analysis. When the procedure was adjusted for the latter variables, CABG (odds ratio 2.246, 95% confidence interval 1.141 to 4.422; p = 0.019), serum creatinine (odds ratio 1.019, 95% confidence interval 1.009 to 1.029; p <0.0001), and emergency procedure (odds ratio 4.725, 95% confidence interval 2.389 to 9.346; p <0.0001) were significantly associated with an increased risk of 30-day mortality (area under the receiver operating characteristics curve 0.747, 95% confidence interval 0.671 to 0.823; p = 0.296, Hosmer-Lemeshow test).
      On univariate analysis, PCI was associated with significantly poorer overall survival (p = 0.004; Table 2), although the freedom from fatal cardiac events was similar between the study groups (p = 0.187, Table 3). Cox regression analysis showed that the treatment methods did not affect either all-cause mortality or cardiac mortality (Table 2, Table 3).
      Table 2Predictors of all-cause mortality in patients aged ≥80 years
      VariableUnivariate Analysis (p Value)Multivariate Analysis (HR, 95% CI)
      Procedure type
      PCI versus CABG.
      0.004
      Age<0.00011.118, 1.056–1.183
      Serum creatinine<0.00011.006, 1.004–1.008
      Pulmonary disease0.0081.941, 1.344–2.804
      Diabetes0.0011.627, 1.193–2.218
      Recent myocardial infarction<0.00011.606, 1.163–2.217
      Ejection fraction ≤50%0.004
      Neurologic dysfunction0.0272.575, 1.254–5.289
      Extracardiac arteriopathy0.0021.557, 1.045–2.319
      Emergency procedure<0.00011.644, 1.202–2.249
      CI = confidence interval; HR = hazard ratio.
      low asterisk PCI versus CABG.
      Table 3Predictors of cardiac mortality in patients aged ≥80 years
      VariableUnivariate Analysis (p Value)Multivariate Analysis (HR, 95% CI)
      Procedure type
      PCI versus CABG.
      0.187
      Age<0.00011.113, 1.035–1.197
      Serum creatinine<0.00011.006, 1.004–1.008
      Pulmonary disease0.0491.928, 1.173–3.171
      Diabetes0.0011.593, 1.060–2.393
      Recent myocardial infarction0.050
      Ejection fraction ≤50%0.003
      Emergency procedure<0.00011.925, 1.284–2.886
      Abbreviations as in Table 2.
      low asterisk PCI versus CABG.
      Logistic regression analysis showed that age (p <0.0001), previous cardiac surgery (p <0.0001), number of diseased vessels (p <0.0001), recent myocardial infarction (p <0.0001), and emergent procedure (p <0.0001) were independent predictors of being assigned to PCI or CABG (area under the receiver operating characteristics curve 0.870, 95% confidence interval 0.843 to 0.897; p = 0.048, Hosmer-Lemeshow test). When adjusted for propensity score, PCI and CABG had similar intermediate all-cause (p = 0.698) and cardiac (p = 0.895) mortality. Propensity score matching resulted in 130 pairs of patients undergoing either CABG or PCI with similar baseline characteristics (Table 1). The intermediate overall mortality (p = 0.730, log-rank test; Table 1 and Figure 1) and freedom from fatal cardiac events (p = 0.648, log-rank test; Figure 2) were similar between the study groups. Such findings did not change even when the treatment method was adjusted for the baseline serum creatinine, a left ventricular ejection fraction ≤50%, and the number of diseased vessels (PCI vs CABG, all-cause mortality, p = 0.948, cardiac mortality, p = 0.428).
      Figure thumbnail gr1
      Figure 1Kaplan-Meier estimates of overall survival in 130 propensity-matched pairs of patients aged ≥80 years who underwent CABG or PCI (log-rank p = 0.730).
      Figure thumbnail gr2
      Figure 2Kaplan-Meier estimates of freedom from fatal cardiac events in 130 propensity-matched pairs of patients aged ≥80 years who underwent CABG or PCI (log-rank p = 0.648).

      Discussion

      Although increased age is a well-known risk factor for adverse events after invasive procedures, satisfactory early and late survival have been reported for patients aged ≥80 years after major cardiovascular surgery.
      • McKellar S.H.
      • Brown M.L.
      • Frye R.L.
      • Schaff H.V.
      • Sundt III, T.M.
      Comparison of coronary revascularization procedures in octogenarians: a systematic review and meta-analysis.
      • Vasques F.
      • Rainio A.
      • Heikkinen J.
      • Mikkola R.
      • Lahtinen J.
      • Kettunen U.
      • Juvonen T.
      • Biancari F.
      Off-pump versus on-pump coronary artery bypass surgery in patients aged 80 years and older: institutional results and meta-analysis.
      • Di Luozzo G.
      • Shirali A.S.
      • Varghese R.
      • Lin H.M.
      • Weiss A.J.
      • Bischoff M.S.
      • Griepp R.B.
      Quality of life and survival of septuagenarians and octogenarians after repair of descending and thoracoabdominal aortic aneurysms.
      • Biancari F.
      • Venermo M.
      Finnish Arterial Disease Investigators
      Open repair of ruptured abdominal aortic aneurysm in patients aged 80 years and older.
      • Vicchio M.
      • Feo M.D.
      • Giordano S.
      • Provenzano R.
      • Cotrufo M.
      • Nappi G.
      Coronary artery bypass grafting associated to aortic valve replacement in the elderly: survival and quality of life.
      • Vasques F.
      • Messori A.
      • Lucenteforte E.
      • Biancari F.
      Immediate and late outcome of patients aged 80 years and older undergoing isolated aortic valve replacement: a systematic review and meta-analysis of 48 studies.
      Increasing evidence has shown the benefits of invasive treatment of coronary artery disease in the elderly. PCI in octogenarians seems to be associated with good early and intermediate results,
      • McKellar S.H.
      • Brown M.L.
      • Frye R.L.
      • Schaff H.V.
      • Sundt III, T.M.
      Comparison of coronary revascularization procedures in octogenarians: a systematic review and meta-analysis.
      • Rittger H.
      • Hochadel M.
      • Behrens S.
      • Hauptmann K.E.
      • Zahn R.
      • Mudra H.
      • Brachmann J.
      • Senges J.
      • Zeymer U.
      Age-related differences in diagnosis, treatment and outcome of acute coronary syndromes: results from the German ALKK registry.
      and the long-term results after CABG can be even better.
      • Vasques F.
      • Rainio A.
      • Heikkinen J.
      • Mikkola R.
      • Lahtinen J.
      • Kettunen U.
      • Juvonen T.
      • Biancari F.
      Off-pump versus on-pump coronary artery bypass surgery in patients aged 80 years and older: institutional results and meta-analysis.
      • Nissinen J.
      • Wistbacka J.O.
      • Loponen P.
      • Korpilahti K.
      • Teittinen K.
      • Virkkilä M.
      • Tarkka M.
      • Biancari F.
      Coronary artery bypass surgery in octogenarians: long-term outcome can be better than expected.
      • Filsoufi F.
      • Rahmanian P.B.
      • Castillo J.G.
      • Chikwe J.
      • Silvay G.
      • Adams D.H.
      Results and predictors of early and late outcomes of coronary artery bypass graft surgery in octogenarians.
      • Baskett R.
      • Buth K.
      • Ghali W.
      • Norris C.
      • Maas T.
      • Maitland A.
      • Ross D.
      • Forgie R.
      • Hirsch G.
      Outcomes in octogenarians undergoing coronary artery bypass grafting.
      Despite these encouraging results, physicians could still be reluctant to refer very elderly patients for invasive treatment of coronary artery disease
      • Rittger H.
      • Schnupp S.
      • Sinha A.M.
      • Breithardt O.A.
      • Schmidt M.
      • Zimmermann S.
      • Mahnkopf C.
      • Brachmann J.
      • Rieber J.
      Predictors of treatment in acute coronary syndromes in the elderly: impact on decision making and clinical outcome after interventional versus conservative treatment.
      because of their perceived prohibitive operative risk and relatively short life expectancy. This can be particularly true for CABG. Indeed, as reported in the present study, the 30-day mortality rate after CABG approaches 10%, and this is of clinical significance. The present results, as well as those from a previous study in Finland,
      • Vasques F.
      • Rainio A.
      • Heikkinen J.
      • Mikkola R.
      • Lahtinen J.
      • Kettunen U.
      • Juvonen T.
      • Biancari F.
      Off-pump versus on-pump coronary artery bypass surgery in patients aged 80 years and older: institutional results and meta-analysis.
      showed that the 5-year survival rate can be >70% and did not significantly differ from that of an age-matched general population (73.3%; Statistics Finland).
      To the best of our knowledge, the present study is the first to address this important issue by comparing the early and intermediate outcomes after PCI and CABG in octogenarians. In contrast to expectations,
      • McKellar S.H.
      • Brown M.L.
      • Frye R.L.
      • Schaff H.V.
      • Sundt III, T.M.
      Comparison of coronary revascularization procedures in octogenarians: a systematic review and meta-analysis.
      in the present series, the early results after PCI were not significantly better than those after CABG, even though the 30-day mortality rate after CABG was somewhat high, because previously reported pooled rates ranged from 6% to 7%.
      • McKellar S.H.
      • Brown M.L.
      • Frye R.L.
      • Schaff H.V.
      • Sundt III, T.M.
      Comparison of coronary revascularization procedures in octogenarians: a systematic review and meta-analysis.
      • Vasques F.
      • Rainio A.
      • Heikkinen J.
      • Mikkola R.
      • Lahtinen J.
      • Kettunen U.
      • Juvonen T.
      • Biancari F.
      Off-pump versus on-pump coronary artery bypass surgery in patients aged 80 years and older: institutional results and meta-analysis.
      We believe our greater rate might have resulted from preoperative selection bias and a local aggressive revascularization policy. The significantly better intermediate survival after CABG in the overall series seemed to be more related to the baseline patient differences than to the treatment modality. A number of patients might have undergone PCI because of a suboptimal functional status. Frailty is a well-recognized factor affecting survival in the elderly in the general population and in patients with acute coronary syndromes or undergoing surgery.
      • Sirola J.
      • Pitkala K.H.
      • Tilvis R.S.
      • Miettinen T.A.
      • Strandberg T.E.
      Definition of frailty in older men according to questionnaire data (RAND-36/SF-36): the Helsinki Businessmen Study.
      • Ekerstad N.
      • Swahn E.
      • Janzon M.
      • Alfredsson J.
      • Löfmark R.
      • Lindenberger M.
      • Carlsson P.
      Frailty is independently associated with short-term outcomes for elderly patients with non–ST-segment elevation myocardial infarction.
      • Partridge J.S.
      • Harari D.
      • Dhesi J.K.
      Frailty in the older surgical patient: a review.
      We were unable to quantify this, because it is not easily discernible from the patient records. It has been previously demonstrated that the assessment of frailty and disability in patients undergoing cardiac surgery risk might improve the discrimination of the operative risk
      • Afilalo J.
      • Mottillo S.
      • Eisenberg M.J.
      • Alexander K.P.
      • Noiseux N.
      • Perrault L.P.
      • Morin J.F.
      • Langlois Y.
      • Ohayon S.M.
      • Monette J.
      • Boivin J.F.
      • Shahian D.M.
      • Bergman H.
      Addition of frailty and disability to cardiac surgery risk scores identifies elderly patients at high risk of mortality or major morbidity.
      ; however, the high rates of false-positive results might diminish their value in clinical decision making.
      • Pijpers E.
      • Ferreira I.
      • Stehouwer C.D.
      • Kruseman N.
      The frailty dilemma: review of the predictive accuracy of major frailty scores.
      • Daniels R.
      • van Rossum E.
      • Beurskens A.
      • van den Heuvel W.
      • de Witte L.
      The predictive validity of three self-report screening instruments for identifying frail older people in the community.
      The unadjusted lower survival of patients aged ≥80 years after PCI compared with after CABG seemed to be related to the disproportionately greater risk of the patients undergoing PCI. However, multivariate analysis showed that survival after PCI was similar to that of patients undergoing CABG when adjusted for other important clinical variables. These findings suggest that PCI might likely broaden the benefits of coronary revascularization to patients not fit for CABG.

      References

        • Population Division, DESA, and United Nations
        (Accessed on March 28, 2012)
        • McKellar S.H.
        • Brown M.L.
        • Frye R.L.
        • Schaff H.V.
        • Sundt III, T.M.
        Comparison of coronary revascularization procedures in octogenarians: a systematic review and meta-analysis.
        Nat Clin Pract Cardiovasc Med. 2008; 5: 738-746
        • Vasques F.
        • Rainio A.
        • Heikkinen J.
        • Mikkola R.
        • Lahtinen J.
        • Kettunen U.
        • Juvonen T.
        • Biancari F.
        Off-pump versus on-pump coronary artery bypass surgery in patients aged 80 years and older: institutional results and meta-analysis.
        Heart Vessels. 2011 Nov 9; (Epub)
        • Nissinen J.
        • Wistbacka J.O.
        • Loponen P.
        • Korpilahti K.
        • Teittinen K.
        • Virkkilä M.
        • Tarkka M.
        • Biancari F.
        Coronary artery bypass surgery in octogenarians: long-term outcome can be better than expected.
        Ann Thorac Surg. 2010; 89: 1119-1124
        • Austin P.C.
        Optimal caliper widths for propensity-score matching when estimating differences in means and differences in proportions in observational studies.
        Pharm Stat. 2011; 10: 150-161
        • Di Luozzo G.
        • Shirali A.S.
        • Varghese R.
        • Lin H.M.
        • Weiss A.J.
        • Bischoff M.S.
        • Griepp R.B.
        Quality of life and survival of septuagenarians and octogenarians after repair of descending and thoracoabdominal aortic aneurysms.
        J Thorac Cardiovasc Surg. 2012 Feb 23; (Epub)
        • Biancari F.
        • Venermo M.
        • Finnish Arterial Disease Investigators
        Open repair of ruptured abdominal aortic aneurysm in patients aged 80 years and older.
        Br J Surg. 2011; 98: 1713-1718
        • Vicchio M.
        • Feo M.D.
        • Giordano S.
        • Provenzano R.
        • Cotrufo M.
        • Nappi G.
        Coronary artery bypass grafting associated to aortic valve replacement in the elderly: survival and quality of life.
        J Cardiothorac Surg. 2012; 7: 13
        • Vasques F.
        • Messori A.
        • Lucenteforte E.
        • Biancari F.
        Immediate and late outcome of patients aged 80 years and older undergoing isolated aortic valve replacement: a systematic review and meta-analysis of 48 studies.
        Am Heart J. 2012; 163: 477-485
        • Rittger H.
        • Hochadel M.
        • Behrens S.
        • Hauptmann K.E.
        • Zahn R.
        • Mudra H.
        • Brachmann J.
        • Senges J.
        • Zeymer U.
        Age-related differences in diagnosis, treatment and outcome of acute coronary syndromes: results from the German ALKK registry.
        EuroIntervention. 2012; 7: 1197-1205
        • Filsoufi F.
        • Rahmanian P.B.
        • Castillo J.G.
        • Chikwe J.
        • Silvay G.
        • Adams D.H.
        Results and predictors of early and late outcomes of coronary artery bypass graft surgery in octogenarians.
        J Cardiothorac Vasc Anesth. 2007; 21: 784-792
        • Baskett R.
        • Buth K.
        • Ghali W.
        • Norris C.
        • Maas T.
        • Maitland A.
        • Ross D.
        • Forgie R.
        • Hirsch G.
        Outcomes in octogenarians undergoing coronary artery bypass grafting.
        Can Med Assoc J. 2005; 172: 1183-1186
        • Rittger H.
        • Schnupp S.
        • Sinha A.M.
        • Breithardt O.A.
        • Schmidt M.
        • Zimmermann S.
        • Mahnkopf C.
        • Brachmann J.
        • Rieber J.
        Predictors of treatment in acute coronary syndromes in the elderly: impact on decision making and clinical outcome after interventional versus conservative treatment.
        Catheter Cardiovasc Interv. 2011 Nov 25; (Epub)
        • Sirola J.
        • Pitkala K.H.
        • Tilvis R.S.
        • Miettinen T.A.
        • Strandberg T.E.
        Definition of frailty in older men according to questionnaire data (RAND-36/SF-36): the Helsinki Businessmen Study.
        J Nutr Health Aging. 2011; 15: 783-787
        • Ekerstad N.
        • Swahn E.
        • Janzon M.
        • Alfredsson J.
        • Löfmark R.
        • Lindenberger M.
        • Carlsson P.
        Frailty is independently associated with short-term outcomes for elderly patients with non–ST-segment elevation myocardial infarction.
        Circulation. 2011; 124: 2397-2404
        • Partridge J.S.
        • Harari D.
        • Dhesi J.K.
        Frailty in the older surgical patient: a review.
        Age Ageing. 2012; 41: 142-147
        • Afilalo J.
        • Mottillo S.
        • Eisenberg M.J.
        • Alexander K.P.
        • Noiseux N.
        • Perrault L.P.
        • Morin J.F.
        • Langlois Y.
        • Ohayon S.M.
        • Monette J.
        • Boivin J.F.
        • Shahian D.M.
        • Bergman H.
        Addition of frailty and disability to cardiac surgery risk scores identifies elderly patients at high risk of mortality or major morbidity.
        Circ Cardiovasc Qual Outcomes. 2012; 5: 222-228
        • Pijpers E.
        • Ferreira I.
        • Stehouwer C.D.
        • Kruseman N.
        The frailty dilemma: review of the predictive accuracy of major frailty scores.
        Eur J Intern Med. 2012; 23: 118-123
        • Daniels R.
        • van Rossum E.
        • Beurskens A.
        • van den Heuvel W.
        • de Witte L.
        The predictive validity of three self-report screening instruments for identifying frail older people in the community.
        BMC Public Health. 2012; 12: 69