Perception of cognitive function in older adults following coronary artery bypass surgery.

This study examined the effects of coronary artery bypass grafting (CABG) on objective and subjective measures of neurocognitive functioning. Participants were 170 older patients (127 men and 43 women; mean age?=?61 years) undergoing CABG. Measures of neurocognitive function, depression, anxiety, and perceived cognitive abilities were administered immediately prior to and 6 weeks following surgery. Although objective measures of impaired cognitive performance following CABG were not related to perceived cognitive difficulties, the presence of anxiety and depression was related to the perception of cognitive functioning. Patients who reported high levels of anxiety and depression 6 weeks after surgery perceived themselves as having poorer cognitive function. Interventions designed to reduce emotional distress could improve patient's perceived cognitive abilities following CABG. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Predictors of long-term change in functional status after coronary artery bypass graft surgery in women

A cohort of 164 women who had undergone coronary artery bypass graft surgery (CABG) was followed for one year to examine changes in functional status and determine the relative influence of clinical, psychosocial and sociodemographic factors on change in functional status outcomes between 6 and 12 months after surgery. Clinical, psychosocial, sociodemographic and preoperative functional status data were collected by written questionnaire and personal interview at the time of surgery and again at 6 and 12 months after CABG. Functional status scores improved significantly from before to 6 months after CABG. Between 6 and 12 months post-CABG 65% sustained or continued to experience improvement in physical functioning, 83% in social and leisure activities, and 54% in psychological functioning. Predictors of sustained improvement in physical functioning were being married, younger age, low 6-month functioning, having an ejection fraction of 50% or greater, and being white. The significant predictors of sustained improvement in social and leisure activities and psychological functioning were being married and low 6-month psychological functioning, respectively. These data suggest that interventions to improve long-term outcomes in women undergoing CABG should take into account not only their age, functional capacity and level of functioning at 6 months post-CABG, but also their race and marital status as potential risk factors for long-term functional status disability.     

Landmarks in the development of coronary artery bypass surgery

Genetic linkage maps have been produced for a wide range of organisms during the last decade, thanks to the increasing availability of molecular markers. The use of microsatellites (or Simple Sequence Repeats, SSRs) as genetic markers has led to the construction of "second-generation" genetic maps for humans, mouse and other organisms of major importance. We constructed a second-generation single-tree genetic linkage map of Norway spruce (Picea abies K.) using a panel of 72 haploid megagametophytes with a total of 447 segregating bands [366 Amplified Fragment Length Polymorphisms (AFLPs), 20 Selective Amplification of Microsatellite Polymorphic Loci (SAMPLs) and 61 SSRs, each single band being treated initially as a dominant marker]. Four hundred and thirteen markers were mapped in 29 linkage groups (including triplets and doublets) covering a genetic length of 2198.3 cM, which represents 77.4% of the estimated genome length of Picea abies (approximately 2839 cM). The map is still far from coalescing into the expected 12 chromosomal linkage groups of Norway spruce (2n = 2x = 24). A possible explanation for this comes from the observed non-random distribution of markers in the framework map. Thirty-eight SSR marker loci could be mapped onto 19 linkage groups. This set of highly informative Sequence Tagged Sites (STSs) can be used in many aspects of genetic analysis of forest trees, such as marker-assisted selection, QTL mapping, positional cloning, gene flow analysis, mating system analysis and genetic diversity studies.     

Outcomes of coronary artery bypass surgery in elderly people

The role of non-invasive nocturnal domiciliary ventilation (NNV) in chronic obstructive pulmonary disease (COPD) patients with chronic hypercapnia is still discussed. The aims of this study were to evaluate the long-term survival, the clinical effectiveness and side-effects of NNV in these patients. Forty-nine stable hypercapnic COPD patients on long-term oxygen therapy (LTOT) were assigned to two groups: in Group 1, 28 patients performed NNV by pressure support modality in addition to LTOT; in Group 2, 21 patients continued their usual LTOT regimen. Treatment was assigned according to the compliance to NNV, after an in hospital period. Mortality rate, hospital stay (HS) and ICU admissions (IA) were recorded in the two groups. HS and IA were compared to those recorded in a similar period of follow-back. Lung and respiratory muscle function, dyspnoea, and exercise capacity (by 6-min walk test) were evaluated baseline and every 3-6 months up to 3 yr. Mean follow-up time was 35 +/- 7 months. Mortality rate was not different between the two groups: 16, 33, 46% and 13, 28, 50% at 1, 2 and 3 yr in Groups 1 and 2 respectively. Lung and respiratory muscle function did not significantly change over time. A significant increase in 6-min walk test (from 245 +/- 78 to 250 +/- 88, 291 +/- 75, 284 +/- 89 m after 1, 2 and 3 yr respectively, P < 0.01) was observed only in patients undergoing NNV. In comparison to the follow back HS significantly decreased in both groups (from 37 +/- 29 to 15 +/- 12 and from 32 +/- 18 to 17 +/- 11 days/pt/yr in Groups 1 and 2 respectively, P < 0.001) whereas IA significantly decreased only in patients performing also NNV (from 1.0 +/- 0.7 to 0.2 +/- 0.3/pt/yr, P < 0.0001). Addition of NNV by pressure support modality to LTOT does not improve long term survival but significantly reduces ICU admissions and improves exercise capacity in severe COPD with hypercapnia.     

Utility of stress single-photon emission computed tomography (SPECT) perfusion imaging in predicting outcome after coronary artery bypass grafting

Previous studies have examined the predictors of outcome in medically treated patients with coronary artery disease (CAD). There is limited information on predictors of outcome after coronary artery bypass grafting (CABG). This study examined the predictors of outcome of 255 patients with CAD, at a mean time of 5 years after CABG for angina pectoris. The 255 patients underwent coronary angiography and stress single-photon emission computed tomography (SPECT) myocardial perfusion imaging after CABG. During a mean follow-up of 41 +/- 28 months after stress testing, there were 34 hard events (24 cardiac deaths and 10 nonfatal myocardial infarctions). The hemodynamics during stress testing, and age and gender were not predictors of events. The SPECT variables of multivessel perfusion abnormality, perfusion deficit size, and increased lung thallium uptake were predictors of death and total events by uni- and multivariate survival analysis. There were 14 events in 45 patients (31%) with multivessel abnormality and increased lung thallium uptake, 14 events in 101 patients (14%) with either multivessel abnormality or increased lung uptake, and 6 events in 109 patients (6%) with neither of these 2 variables (p = 0.0001). The annual mortality and total event rates were 7.5% and 9.5% with both variables, 3.4% and 4.3% with either variable, and 0.6% and 1.7% with neither of the variables (p = 0.01). Thus, stress SPECT perfusion imaging is useful to stratify patients after CABG into low, intermediate, and high risk groups for future cardiac events.     

Elimination of cardiopulmonary bypass: a prime goal in reoperative coronary artery bypass surgery

OBJECTIVE: The purpose of this study was to evaluate morbidity and mortality in reoperative coronary artery bypass surgery using the New York State database. METHODS: Patients undergoing reoperative coronary artery bypass between January-1995 and December 1996 were included. Patients were operated using cardiopulmonary bypass (CPB group, n = 184) or without cardiopulmonary bypass (non-CPB group, n = 105) by surgeon preference. Groups were compared for preoperative risk factors, postoperative mortality and major complications. RESULTS: Crude mortality was lower in the non-CPB group, despite a higher expected mortality, resulting in a risk-adjusted mortality of 1.3% versus 2.7% for the CPB group (NS). Of non-CPB patients, 91.4% were without complications, while only 72.1% of CPB patients (P < 0.0001) were complication-free. Major complications were significantly reduced in non-CPB patients compared to CPB patients: stroke 0% versus 3.8% (P < 0.04), cardiovascular complications 4.8% versus 15.8% (P < 0.005), other major complications 1.9% versus 10.4% (P < 0.007). Postoperative IABP support was needed in 1.9% of the non-CPB group patients and in 14.2% of the CPB group (P < 0.0007). CONCLUSIONS: The main object of reoperative CABG is to relieve symptoms, since the survival benefit of the procedure has not been demonstrated. Performance of reoperative coronary artery bypass surgery without cardiopulmonary bypass significantly reduces morbidity. We conclude that cardiopulmonary bypass should be avoided whenever possible in reoperative coronary bypass surgery.     

Change in anaesthesia practice and postoperative sedation shortens ICU and hospital length of stay following coronary artery bypass surgery

We randomized prospectively 144 patients, undergoing elective coronary artery bypass surgery, to either early or to routine extubation [mechanical ventilatory support for 4-7 h (Group A), or 8-14 h (Group B)]. Anaesthesia was modified for both groups. The groups were well matched in terms of sex, age, NYHA class, preoperative left ventricular ejection fraction, bypass time and aortic cross-clamp time, number of grafts used, and blood units transfused. All patients had normal preoperative respiratory, renal, hepatic and cerebral functions. Mechanical ventilatory support (mean +/- SD) was 6.3 +/- 0.7 h for Group A and 11.6 +/- 1.3 h for Group B. Mean ICU stay was 17 +/- 1.3 h for Group A and 22 +/- 1.2 h for Group B, while the mean hospital stay was 7.3 +/- 0.8 days and 8.4 +/- 0.9, respectively. There were no statistically significant differences in the frequency of all postoperative complications among the two groups. There were no reintubation, readmission to the ICU or death in either group. We concluded that change in anaesthesia practice and early postoperative sedation in patients undergoing elective coronary artery bypass graft (CABG) surgery resulted in earlier tracheal extubation, shorter ICU and hospital length of stay without organ dysfunction or postoperative complications. Early extubation was only possible due to the modification of anaesthesia and ICU sedation regime.     

Thrombogenic and atherogenic lipid modifications in plasma and patients with coronary artery disease and after coronary artery bypass surgery

BACKGROUND: Although multiple studies have shown that the left ventricular assist device (LVAD) improves distorted cardiac geometry, the pathological mechanisms of the "reverse remodeling" of the heart are unknown. Our goal was to determine the effects of LVAD support on cardiac myocyte size and shape. METHODS AND RESULTS: Isolated myocytes were obtained at cardiac transplantation from 30 failing hearts (12 ischemic, 18 nonischemic) without LVAD support, 10 failing hearts that received LVAD support for 75+/-15 days, and 6 nonfailing hearts. Cardiac myocyte volume, length, width, and thickness were determined by use of previously validated techniques. Isolated myocytes from myopathic hearts exhibited increased volume, length, width, and length-to-thickness ratio compared with normal myocytes (P<0.05). However, there were no differences in any parameter between myocytes from ischemic and nonischemic cardiomyopathic hearts. Long-term LVAD support resulted in a 28% reduction in myocyte volume, 20% reduction in cell length, 20% reduction in cell width, and 32% reduction in cell length-to-thickness ratio (P<0.05). In contrast, LVAD support was associated with no change in cell thickness. These cellular changes were associated with reductions in left ventricular dilation and left ventricular mass measured echocardiographically in 6 of 10 LVAD-supported patients. CONCLUSIONS: These studies suggest that the regression of cellular hypertrophy is a major contributor to the "reverse remodeling" of the heart after LVAD implantation. The favorable alterations in geometry that occur in parallel fashion at both the organ and cellular levels may contribute to reduced wall stress and improved mechanical performance after LVAD support.     

Management of unstable coronary syndromes in patients with previous coronary artery bypass grafts following coronary angiography

A recent survey of psychiatric research indicates religion has been given little attention, and when it has been considered, the measures have been simplistic. The present study was designed to describe the religious needs and resources of psychiatric inpatients. With the use of a multidimensional conception of religion and two established instruments, 51 adult psychiatric inpatients were surveyed about their religious needs and resources. For comparison, 50 general medical/surgical patients, matched for age and gender, were also surveyed. Eighty-eight percent of the psychiatric patients reported three or more current religious needs. Although there were no differences in religious needs between the two patient groups, there were significant differences in religious resources. Psychiatric patients had lower spiritual well-being scores and were less likely to have talked with their clergy. Religion is important for the psychiatric patients, but they may need assistance to find resources to address their religious needs.     

Outcome of coronary bypass surgery versus coronary angioplasty in diabetic patients with multivessel coronary artery disease

The coloration of cells of the cyanobacterium Synechococcus sp. PCC 7002 changed from normal blue-green to yellow-green when cells were grown at 15 degrees C in a medium containing nitrate as the sole nitrogen source. This change of coloration was similar to a general response to nutrient deprivation (chlorosis). For the chlorotic cells at 15 degrees C, the total amounts of phycobiliproteins and chlorophyll a decreased, high levels of glycogen accumulated, and growth was arithmetic rather than exponential. These changes in composition and growth occurred in cells grown at low (50 microE m-2 s-1) as well as high (250 microE m-2 s-1) light intensity. After a temperature shift-up to 38 degrees C, chlorotic cells rapidly regained their normal blue-green coloration and normal exponential growth rate within 7 h. When cells were grown at 15 degrees C in a medium containing urea as the reduced nitrogen source, cells grew exponentially and the symptoms of chlorosis were not observed. The decrease in photosynthetic oxygen evolution activity at low temperature was much smaller than the decrease in growth rate for cells grown on nitrate as the nitrogen source. These studies demonstrate that low-temperature-induced chlorosis of Synechococcus sp. PCC 7002 is caused by nitrogen limitation and is not the result of limited photosynthetic activity or photodamage to the photosynthetic apparatus, and that nitrogen assimilation is an important aspect of the low-temperature physiology of cyanobacteria.     

Efficacy of epidural analgesia in minimally invasive direct coronary artery bypass surgery

Minimally invasive direct coronary artery bypass surgery (MIDCAB), coronary bypass grafting with small thoracotomy using no cardiopulmonary bypass (CPB), became popular recently. To attenuate perioperative stress-response, we used epidural analgesia (EPI) with general anesthesia for MIDCAB operation. In this study, we compared retrospectively 11 cases of MIDCAB managed with EPI [ED (+)], and 14 cases of MIDCAB anesthetized without using EPI [ED (-)], concerning extubation time, ICU stay, hospital stay and perioperative complications. The mean time from cessation of general anesthesia to extubation was significantly shorter in ED (+) patients (0.5 hours) when compared to ED (-) patients (18.2 hours). Mean periods of ICU stay and hospital stay were, also, shorter in ED (+) patients (2.1 days, 30.5 days, respectively) when compared to ED (-) (4.3 days, 45.1 days, respectively) patients. We experienced ventricular tachycardia in three patients of ED (-). No major complication occurred in ED (+) patients. These results suggest that EPI shortened extubation time, ICU and hospital stay for MIDCAB patients.     

The value of donor iliac artery pressure gradients in predicting the outcome of femorofemoral bypass

PURPOSE: This study tests the clinical value of femoral artery pressure measurements by analysis of the relationship between iliac artery pressure gradients (PGs) and both femorofemoral bypass graft patency and the hemodynamic changes produced in the donor and recipient limbs. METHODS: Systemic and donor femoral artery systolic and mean pressures were measured during surgery at rest and during papaverine-induced hyperemia before 94 femorofemoral bypasses. Ankle/brachial (A/B) pressure ratios and pulse volume recordings (PVRs) were measured before and early after surgery. Donor iliac artery stenosis was 25% +/- 23% (mean +/- 1 SD). Follow-up was 23+/- 20 months. RESULTS: Eight bypasses failed at 21 +/- 20 months. Patients with failed bypasses had a resting systolic and mean PG of 23 +/- 22 mm Hg and 5 +/- 7 mm Hg, respectively, compared with 10 +/- 11 mm Hg (p = 0.007) and 1 +/- 2 mm Hg (p = 0.001) for the 86 patent bypasses. Donor limb A/B ratios and PVRs decreased 9% +/- 5% and 15% +/- 14%, respectively, had a linear regression slope less than 0 (p < 0.05) with resting and hyperemic PGs, and correlated best with resting PGs (p < 0.05). Recipient limb A/B ratios and PVRs increased 86% +/- 48% and 191% +/- 111%, respectively, had a linear regression slope greater than 0 (p < 0.05) with all resting and hyperemic PGs, and correlated best with hyperemic systolic PGs (p < 0.05). However, all regressions had a large SD, wide 95% confidence limit, and a low correlation coefficient. Sensitivity-specificity receiver-operating characteristic curves for optimal PG criteria for both graft failure and donor limb hemodynamic impairment are weak, with an accuracy of 50% to 75%. Recommended criteria for not performing a femorofemoral bypass are a resting systolic PG of 28 mm Hg or greater or a resting mean PG of 6 mm Hg or greater. CONCLUSIONS: Although iliac artery PGs correlate with graft failure and both the degree of donor limb hemodynamic impairment and recipient limb improvement, the large variability in PGs between patients with similar outcomes and the low accuracy of optimal PG criteria indicate that they have limited clinical value in decision making.     

Short- and long-term prognosis after coronary artery bypass grafting in relation to smoking habits

A study was conducted to determine the conditions needed to achieve the equilibrium concentration for the epimerization of d-lysergic acid diethylamide (LSD) to iso-LSD. The reaction was followed by integration of the C-9 resonance of LSD and iso-LSD by proton nuclear magnetic resonance (NMR). The C-9 resonance of LSD and iso-LSD appear as singlets at 6.35 and 6.27 ppm respectively. Starting with pure LSD, the conversion to iso-LSD is attained at temperatures above 37 degrees C and pH levels over 7.0. At a pH of 7.0 or higher, the LSD/iso-LSD ratio of 9:1 is achieved after one week at 45 degrees C or two weeks at 37 degrees C. Starting with iso-LSD, the conversion to LSD requires more vigorous conditions. The 9:1 LSD/iso-LSD ratio is attained only after 6 weeks at a temperature of 45 degrees C and a pH of 9.7. At lower pH levels, the reaction proceeds more slowly. The 9:1 LSD/iso-LSD ratio is achieved whether the starting material is LSD or iso-LSD and therefore represents an equilibrium concentration (K = 9). In addition, the more vigorous conditions needed to achieve equilibrium of iso-LSD to LSD demonstrate the difficulty in extraction of the epimerizable proton of iso-LSD. This study is the first to quantitate the epimerization of LSD by NMR techniques and establishes the conditions needed to induce epimerization in solution.     

New electrocardiographic criteria for predicting the site of coronary artery occlusion in inferior wall acute myocardial infarction

In patients with inferior wall acute myocardial infarction (AMI), the site of the culprit lesion is an important determinant of outcome. Patients with right ventricular infarction have a poor prognosis, whereas those with occlusion of the left circumflex coronary artery (LCx) have a good prognosis. Therefore, we assessed whether standard 12-lead electrocardiograms obtained on admission could identify the site of coronary artery occlusion, (i.e., a site proximal to the origin of the right ventricular branch of the right coronary artery [RCA], a site distal to the origin of the right ventricular branch of the RCA, or a site in the LCx). The ratio of ST depression in lead V3 to ST elevation in lead III (V3/III ratio) was evaluated immediately before coronary angiography in 152 patients with a first inferior wall AMI confirmed by coronary angiography within 12 hours after the onset of symptoms. For occlusion of the proximal RCA, distal RCA, and LCx, V3/III ratio was 0.2+/-0.3, 0.8+/-0.5, and 2.5+/-2.5 (p = 0.0001), respectively. The V3/III ratio <0.5 identified proximal RCA occlusion, 0.5 相似文献   

Comparison of long-term efficacy of medical treatment versus coronary artery bypass grafting (CABG) in multivessel coronary artery disease

The long-term results of medical therapy and coronary artery bypass grafting (CABG) were compared in patients with multivessel disease. All patients were confirmed to have > or = 75% luminal narrowing of major coronary arteries by coronary arteriogram. When multivessel disease was stratified into double- and triple- vessel disease, the outcomes varied. In triple-vessel disease, the outcome with CABG was good, but the outcome was unfavorable in those employing medical therapy, particularly in patients with decreased left ventricular (LV) function. In patients with double-vessel disease with good LV function, the long-term results with medical therapy were just as favorable as those with CABG. However, double-vessel disease complicated by reduced LV function (ejection faction < or = 40%) had a clearly less favorable outcome when treated with medical therapy than with CABG. Thus, it is important for patients with multivessel disease to undergo revascularization if indicated, to improve their prognosis. On the other hand, the incidence of cardiac events arising from vein graft occlusions tended to increase in CABG patients after 5 years or more following surgery.     

Impact of embolization during coronary artery bypass grafting on outcome and length of stay

BACKGROUND: Transcranial Doppler ultrasonography detects emboli in most patients during coronary artery bypass grafting. However, the significance of these emboli has not yet been established. METHODS: We monitored 82 patients during coronary artery bypass grafting with this technique and related the numbers of emboli to the outcomes and length of hospital stay. RESULTS: We detected cerebral emboli in all patients. Patients with stroke (n = 4; 4.9%) had a mean of 449 emboli, as compared with 169 emboli in patients without stroke (n = 78) (p = 0.005). Patients with major cardiac complications (n = 7) had a mean of 392 emboli, as compared with 163 in patients without such complications (n = 75) (p = 0.003). The mean hospital stay of survivors was 8.6 days in patients with fewer than 100 emboli (n = 40), 13.5 days in patients with 101 to 300 emboli (n = 23), 16.3 days in those with 301 to 500 emboli (n = 16), and 55.8 days in patients with more than 500 emboli (n = 6) (p = 0.0007). This relation was unchanged when patients with complications were excluded. The correlation between embolization and outcome was independent of the extent of aortic atheroma or age. CONCLUSIONS: Emboli detected during coronary artery bypass grafting are significantly related to major cardiac and neurologic complications and affect length of stay in all patients, even in the absence of such specific complications.     

Inotropic reserve and histological appearance of hibernating myocardium in conscious pigs with ameroid-induced coronary stenosis

Inotropic reserve, demonstrated with administration of sympathomimetic amines, is characteristic of hibernating myocardium. The goal of this study was to determine whether inotropic reserve was present following chronic coronary artery constriction in the pig, which is one potential model of hibernating myocardium. The effects of isoproterenol were examined in five conscious pigs 21 +/- 2.1 days after ameroid implantation on the left circumflex coronary artery on measurements of left ventricular (LV) pressure, LV dP/dt, and regional wall thickening in the ameroid-dependent zone (posterior wall) and contralateral non-ischemic zone (anterior wall). Isoproterenol, 0.1 microgram/kg/min, increased LV dP/dt by 96 +/- 11%, heart rate by 43 +/- 13 beats/min, and normalized systolic wall thickening, slightly, but not significantly more in the ameroid-dependent zone (+1.57 +/- 0.31 mm) than in the contralateral non-ischemic zone (+1.04 +/- 0.31 mm), although the baseline wall thickening was reduced significantly in the ameroid-dependent zone. This occurred at a time when baseline myocardial blood flow was preserved and myocardial perfusion in the ameroid-dependent zone was derived in part from the native coronary circulation and also through collateral channels. Two weeks later histological evidence of lesions characteristic of hibernating myocardium, i.e., myofibrolysis and increased glycogen deposition, were observed. Thus, these histological changes and the confluence of chronically depressed regional function and residual inotropic reserve in the conscious pig with chronic ameroid-induced coronary constriction support this model for further study of hibernating myocardium.     

Improved outcome after coronary bypass surgery in patients with ischemic cardiomyopathy and residual myocardial viability

BACKGROUND: Although residual myocardial viability in patients with coronary artery disease and extensive regional asynergy is associated with improved ventricular function after coronary bypass surgery, the relationship between viability and clinical outcome after surgery is unclear. We hypothesized that patients with poor ventricular function and predominantly viable myocardium have a better outcome after bypass surgery compared with those with less viability. METHODS AND RESULTS: Seventy patients with multivessel coronary artery disease and left ventricular ejection fractions < 40% who underwent preoperative quantitative 201Tl scintigraphy before coronary bypass surgery were analyzed retrospectively. 201Tl scintigrams were reviewed blindly, and each segment was assigned a score based on defect magnitude. Segmental viability scores were summed and divided by the number of segments visualized to determine a viability index. The viability index was significantly related to 3-year survival free of cardiac event (cardiac death or heart transplant) after bypass surgery (P=.011) and was independent of age, ejection fraction, and number of diseased coronary vessels. Patients with greater viability (group 1; viability index > 0.67; n=33) were similar to patients with less viability (group 2; viability index < or = 0.67; n=37) with respect to age, comorbidities, and extent of coronary artery disease. There were 6 cardiac deaths and no heart transplants in group 1 patients and 15 cardiac deaths and two transplants in group 2 patients. Survival free of cardiac death or transplantation was significantly better in group 1 patients on Kaplan-Meier analysis (P=.018). CONCLUSIONS: We conclude that resting 201Tl scintigraphy may be useful in preoperative risk stratification for identification of patients more likely to benefit from surgical revascularization.     

Morbidity, cost, and six-month outcome of minimally invasive direct coronary artery bypass grafting

BACKGROUND: Minimally invasive direct coronary artery bypass grafting (MIDCABG) promises to reduce the morbidity of coronary bypass, but this has not been proved. METHODS: This retrospective study compares the morbidity, mortality, cost, and 6-month outcome of patients less than 80 years old undergoing elective left internal mammary artery to left anterior descending artery bypass grafting via MIDCABG (n = 60) or sternotomy (n = 55) between January 1995 and December 1996. There were no differences between the groups in mean age, sex distribution, or preoperative risk level. The left internal mammary artery was mobilized from the fifth costal cartilage to the subclavian artery in all patients. The anastomoses were done with a beating heart in the MIDCABG group and with cardioplegic arrest in the sternotomy group. RESULTS: There were no operative deaths in either group. The MIDCABG patients had a lower transfusion incidence (10/60 [17%] versus 22/55 [40%]; p< or =0.02) and a shorter postoperative intubation time (2.1+/-4.2 versus 12.6+/-9 hours; p< or =0.0001). One patient in each group was reexplored for bleeding. Three sternotomy patients (3/55, 5%) required ventilatory support for greater than 48 hours, but no MIDCABG patient was ventilated for more than 24 hours. Median postoperative length of stay was 4 days for MIDCABG and 7 days for sternotomy. Estimated hospital costs were $11,200+/-3100 for MIDCABG and $15,600+/-4200 for CABG (p < 0.001). The reduced morbidity and cost of MIDCABG was found mostly in high-risk patients. At 6-month follow-up, 5 MIDCABG patients (5/60, 8%) had evidence of recurrent ischemia involving the left anterior descending artery, primarily the result of anastomotic stricture. CONCLUSIONS: This analysis shows that MIDCABG reduces the initial morbidity and cost of coronary bypass, but some patients require subsequent reintervention. Long-term follow-up is needed before MIDCABG can be judged better than traditional bypass, but the initial results are promising, especially in high-risk patients.     

Magnetic resonance spectroscopy of high-energy phosphates and lactate immediately after coronary artery bypass surgery

Hypothermic cardiopulmonary bypass (CPB) is associated with a high incidence of neuropsychological defects, marked cerebral swelling immediately after surgery and jugular bulb desaturation during rewarming. This suggests cerebral ischaemia may occur, but evidence is indirect. We studied four patients with 31P magnetic resonance spectroscopy (MRS) and four with 1H MRS before and immediately after coronary surgery. There was no visible lactate in 1H MR spectra. In 31P MR spectra, the ratio of phosphocreatine to adenosine triphosphate was maintained (before: 2.13 +/- 0.86 vs after: 2.57 +/- 1.31; mean +/- 1 SD) and there was no intracellular acidosis (intracellular pH: 7.1 +/- 0.04 vs 7.16 +/- 0.08), while phosphocreatine/inorganic phosphate was increased immediately after the operation (2.92 +/- 0.37 vs 6.39 +/- 2.67, p = 0.03). This suggests rebound replacement of energy stores following recovery from temporary cerebral ischaemia during CPB: intra-operative studies would be needed to test this hypothesis further.