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The impact of customized blood pressure during cardiopulmonary bypass
Abstracts / Journal of Clinical Epidemiology 56 (2003) 920–923
2001 through October 2002) to identify case-control studies that described a gene-gene, gene-environment, or gene-drug interaction on risk of disease. For each of the eligible articles, we determined whether or not an internal prediction error was reported. Results: Of the nine eligible studies, only one presented an internal prediction error. The most frequently used analytic method in the studies published in the general medical journals was logistic regression. In contrast, a greater variety of analytic techniques, some specifically developed for genetic investigations, were employed in the studies published in the American Journal of Human Genetics. The study presenting an internal prediction error was set apart in that the Multifactor Dimensionality Reduction (MDR) method of analysis was used, designed to detect interactions with moderate sample sizes. An internal prediction error is automatically included in the MDR output, but not in most standard logistic regression software packages. Conclusion: An internal prediction error is infrequently reported in case-control studies of genetic interactions. In addition to educating investigators and clinicians regarding the importance of reporting this measure, the addition of prediction error capabilities to standard logistic regression software packages would facilitate routine reporting. doi: 10.1016/S0895-4356(03)00235-X
THE IMPACT OF CUSTOMIZED BLOOD PRESSURE DURING CARDIOPULMONARY BYPASS Peterson JC, Krieger KH, Isom OW, Charlson ME Weill Medical College of Cornell University Background: We have previously examined mean arterial pressure (MAP) during coronary artery bypass graft (CABG) surgery and showed that a high MAP during cardiopulmonary bypass (CPB) of 80 mmHg resulted in significantly less morbidity and mortality when compared to usual MAP (50–60 mmHg). The purpose of this new randomized trial among elective CABG patients was to compare the efficacy of 2 strategies of MAP management during CPB: 80 mmHg (“Standard”) vs. a tailored MAP (“Custom”) determined by the patient’s pre-bypass MAP on major morbidity, mortality and quality of life. Methods: 412 patients undergoing primary elective CABG were prospectively studied. Pre-operatively, standard cardiac and neurologic exams were done, as was the Charlson Comorbidity Index and the SF-36 Health Survey. Intra-operative monitoring included downloaded MAP’s medications and duration of CPB. At 6 months, an interval history was obtained, cardiac and neurologic exams were repeated and the SF-36 was readministered. Results: The study groups did not differ at baseline with respect to age, gender, race and cardiac history. Overall, their mean age 64.7 years, with 71% Caucasian and 64% male. The mean ejection fraction was 44%. Intra-operatively, there were no differences with respect to pre-bypass MAP, medication doses or CPB pump flows between the 2 groups. The MAP’s achieved during CPB demonstrated that the randomization MAP was attained for both groups. The duration of CPB was similar in the standard and custom groups (74.3 vs. 76.7 min.) as was the cross clamp application time (39.7 vs. 40.4 min.). At 6 months, both groups reported significant improvement in all domains of the SF-36 when compared to baseline.
Cardiac morbidity and mortality Neurologic morbidity and mortality Combined cardiac/neurologic Other mortality Total
923
Standard (n ⫽ 206)
Custom (n ⫽ 206)
5.3% (11) 3.4% (7) 1.5% (3) 1.5% (3) 11.7% (24)
6.8% (14) 3.9% (8) — 1.9% (4) 12.6% (26)
Conclusions: A patient-specific, customized approach to intraoperative MAP during CPB did not further reduce post-operative morbidity/mortality or prevent dysfunction when compared to 80 mmHg. doi: 10.1016/S0895-4356(03)00230-0
THE CASE FOR AGE DISCRIMINATION IN THE ALLOCATION OF CADAVERIC KIDNEYS Votruba Mark E Case Western Reserve University, Cleveland, OH Background: Given the shortage of cadaveric kidneys available for renal transplantation, difficult decisions must be made regarding their allocation to patients suffering end-stage renal disease (ESRD). Promoting allocations to younger transplant candidates could increase the aggregate health benefits generated from the limited supply of organs, but necessarily reduces transplantation access of elderly candidates. Methods: Using data on 129,547 ESRD patients placed on the transplant waiting list between 1987 and 1997, the author estimates the independent effect of candidate age on the hazard rates of pretransplant mortality, post-transplant mortality and post-transplant graft failure. The estimated parameters of these models are used to calculate differences in the expected health benefits (increased life expectancy and graft survival time) generated from transplantation of candidates of different ages. Allocations and subsequent patient outcomes are simulated for a hypothetical region under the current allocation system and under a proposed system that promotes allocations to candidates with larger expected health benefits from transplantation as predicted by their age. Results: Middle aged transplant recipients receive substantially smaller health benefits from transplantation that elderly recipients. The expected graft survival time of recipients aged 40–49 exceeds that of recipients aged 60–69 by almost 2.6 years. The increase in life expectancy generated from transplantation is about 8 years higher for recipients aged 40–49 relative to those aged 60–69. Simulations suggest that promoting allocations to younger candidates could increase the average number of life years generated per cadaveric transplant by 25% and the average duration of graft function by 10%. However, allocations to elderly candidates would be nearly eliminated. Conclusions: Discriminating in favor of middle age transplant candidates over elderly candidates in the allocation of cadaveric kidneys would substantially increase the aggregate health of the candidate pool, but at the cost of reducing transplantation access of elderly candidates. Though questionable on ethical (equity) grounds, this proposal can be viewed as an extension to the preference already bestowed on candidates under age 18. doi: 10.1016/S0895-4356(03)00231-2
2001 through October 2002) to identify case-control studies that described a gene-gene, gene-environment, or gene-drug interaction on risk of disease. For each of the eligible articles, we determined whether or not an internal prediction error was reported. Results: Of the nine eligible studies, only one presented an internal prediction error. The most frequently used analytic method in the studies published in the general medical journals was logistic regression. In contrast, a greater variety of analytic techniques, some specifically developed for genetic investigations, were employed in the studies published in the American Journal of Human Genetics. The study presenting an internal prediction error was set apart in that the Multifactor Dimensionality Reduction (MDR) method of analysis was used, designed to detect interactions with moderate sample sizes. An internal prediction error is automatically included in the MDR output, but not in most standard logistic regression software packages. Conclusion: An internal prediction error is infrequently reported in case-control studies of genetic interactions. In addition to educating investigators and clinicians regarding the importance of reporting this measure, the addition of prediction error capabilities to standard logistic regression software packages would facilitate routine reporting. doi: 10.1016/S0895-4356(03)00235-X
THE IMPACT OF CUSTOMIZED BLOOD PRESSURE DURING CARDIOPULMONARY BYPASS Peterson JC, Krieger KH, Isom OW, Charlson ME Weill Medical College of Cornell University Background: We have previously examined mean arterial pressure (MAP) during coronary artery bypass graft (CABG) surgery and showed that a high MAP during cardiopulmonary bypass (CPB) of 80 mmHg resulted in significantly less morbidity and mortality when compared to usual MAP (50–60 mmHg). The purpose of this new randomized trial among elective CABG patients was to compare the efficacy of 2 strategies of MAP management during CPB: 80 mmHg (“Standard”) vs. a tailored MAP (“Custom”) determined by the patient’s pre-bypass MAP on major morbidity, mortality and quality of life. Methods: 412 patients undergoing primary elective CABG were prospectively studied. Pre-operatively, standard cardiac and neurologic exams were done, as was the Charlson Comorbidity Index and the SF-36 Health Survey. Intra-operative monitoring included downloaded MAP’s medications and duration of CPB. At 6 months, an interval history was obtained, cardiac and neurologic exams were repeated and the SF-36 was readministered. Results: The study groups did not differ at baseline with respect to age, gender, race and cardiac history. Overall, their mean age 64.7 years, with 71% Caucasian and 64% male. The mean ejection fraction was 44%. Intra-operatively, there were no differences with respect to pre-bypass MAP, medication doses or CPB pump flows between the 2 groups. The MAP’s achieved during CPB demonstrated that the randomization MAP was attained for both groups. The duration of CPB was similar in the standard and custom groups (74.3 vs. 76.7 min.) as was the cross clamp application time (39.7 vs. 40.4 min.). At 6 months, both groups reported significant improvement in all domains of the SF-36 when compared to baseline.
Cardiac morbidity and mortality Neurologic morbidity and mortality Combined cardiac/neurologic Other mortality Total
923
Standard (n ⫽ 206)
Custom (n ⫽ 206)
5.3% (11) 3.4% (7) 1.5% (3) 1.5% (3) 11.7% (24)
6.8% (14) 3.9% (8) — 1.9% (4) 12.6% (26)
Conclusions: A patient-specific, customized approach to intraoperative MAP during CPB did not further reduce post-operative morbidity/mortality or prevent dysfunction when compared to 80 mmHg. doi: 10.1016/S0895-4356(03)00230-0
THE CASE FOR AGE DISCRIMINATION IN THE ALLOCATION OF CADAVERIC KIDNEYS Votruba Mark E Case Western Reserve University, Cleveland, OH Background: Given the shortage of cadaveric kidneys available for renal transplantation, difficult decisions must be made regarding their allocation to patients suffering end-stage renal disease (ESRD). Promoting allocations to younger transplant candidates could increase the aggregate health benefits generated from the limited supply of organs, but necessarily reduces transplantation access of elderly candidates. Methods: Using data on 129,547 ESRD patients placed on the transplant waiting list between 1987 and 1997, the author estimates the independent effect of candidate age on the hazard rates of pretransplant mortality, post-transplant mortality and post-transplant graft failure. The estimated parameters of these models are used to calculate differences in the expected health benefits (increased life expectancy and graft survival time) generated from transplantation of candidates of different ages. Allocations and subsequent patient outcomes are simulated for a hypothetical region under the current allocation system and under a proposed system that promotes allocations to candidates with larger expected health benefits from transplantation as predicted by their age. Results: Middle aged transplant recipients receive substantially smaller health benefits from transplantation that elderly recipients. The expected graft survival time of recipients aged 40–49 exceeds that of recipients aged 60–69 by almost 2.6 years. The increase in life expectancy generated from transplantation is about 8 years higher for recipients aged 40–49 relative to those aged 60–69. Simulations suggest that promoting allocations to younger candidates could increase the average number of life years generated per cadaveric transplant by 25% and the average duration of graft function by 10%. However, allocations to elderly candidates would be nearly eliminated. Conclusions: Discriminating in favor of middle age transplant candidates over elderly candidates in the allocation of cadaveric kidneys would substantially increase the aggregate health of the candidate pool, but at the cost of reducing transplantation access of elderly candidates. Though questionable on ethical (equity) grounds, this proposal can be viewed as an extension to the preference already bestowed on candidates under age 18. doi: 10.1016/S0895-4356(03)00231-2