Exercise training after coronary angioplasty improves cardiorespiratory function

Aim. The aim of this prospective randomized study was to evaluate the impact of long-term aerobic exercise training on respiratory function, left ventricular systolic function and remodeling in patients with coronary heart disease and ischemic heart failure after successful angioplasty. Design. Patients (n=185) have undergone Doppler echocardiography and ergospirometry. Ninety-five patients practiced 6 month-term aerobic exercise training, less by 10% to their anaerobic threshold. Ninety patients were studied as controls. They were given only drug treatment without training. Measurements were repeated after 6 and 12 months. Results. Training group patients after 6 months showed significant (p<0.05) improvement in exercise capacity, oxygen consumption and ventilating equivalents. The Doppler echocardiographic findings revealed significant (p<0.05) improvement in ejection fraction, left ventricular and atria morphometric data. Improved ergospirometric and echocardiographic data were established after 12 months, too. Conclusions. Long-term aerobic exercise training is an effective and workable measure improving respiratory efficiency, left ventricular systolic function, attenuating negative remodeling and stopping further progression in patients with coronary heart disease and chronic heart failure after successful angioplasty.     

Normoxic ventilatory resuscitation following controlled cortical impact reduces peroxynitrite-mediated protein nitration in the hippocampus

OBJECTIVES: Ventilatory resuscitation with 100% O2 after severe traumatic brain injury (TBI) raises concerns about the increased production of reactive oxygen species (ROS). The product of peroxynitrite-meditated tyrosine residue nitration, 3-nitrotyrosine (3-NT), is a marker for oxidative damage to proteins. The authors hypothesized that posttraumatic resuscitation with hyperoxia (100% fraction of inspired oxygen [FiO2] concentration) results in increased ROS-induced damage to proteins compared with resuscitation using normoxia (21% FiO2 concentration). METHODS: Male Sprague-Dawley rats underwent controlled cortical impact (CCI) injury and resuscitation with either normoxic or hyperoxic ventilation for 1 hour (5 rats per group). Twenty-four hours after injury, rat hippocampi were evaluated using 3-NT immunostaining. In a second experiment, animals similarly underwent CCI injury and normoxic or hyperoxic ventilation for 1 hour (4 rats per group). One week after injury, neuronal counts were performed after neuronal nuclei immunostaining. RESULTS: The 3-NT staining was significantly increased in the hippocampi of the hyperoxic group. The normoxic group showed a 51.0% reduction of staining in the CA1 region compared with the hyperoxic group and a 50.8% reduction in the CA3 region (p < 0.05, both regions). There was no significant difference in staining between the injured normoxic group and sham-operated control groups. In the delayed analysis of neuronal survival (neuronal counts), there was no significant difference between the hyperoxic and normoxic groups. CONCLUSIONS: In this clinically relevant model of TBI, normoxic resuscitation significantly reduced oxidative damage to proteins compared with hyperoxic resuscitation. Neuronal counts showed no benefit from hyperoxic resuscitation. These findings indicate that hyperoxic ventilation in the early stages after severe TBI may exacerbate oxidative damage to proteins.     

Persistent myocardial ischemia following chronic hyperoxia in conscious dogs

Following acute occlusion of the proximal left anterior descending (LAD) coronary artery, dogs were exposed continuously for 4 days in an environmental chamber to either 21% or 40% oxygen. Regional transmural myocardial blood flow was then determined by means of radioactive microspheres (8 to 10 microD) while each animal breathed room air (approximately equal to 21% oxygen). Blood flows in the anterolateral and apical regions of the left ventricle in normoxic animals (n = 5) averaged 0.95 +/- 0.03 and 0.69 +/- 0.13 ml/min X gm-1, respectively. In hyperoxic dogs (n = 5), blood flows in these regions were significantly lower, averaging 0.71 +/- 0.07 and 0.28 +/- 0.08 ml/min X gm-1, respectively in the anterolateral free wall, the greatest disparity in perfusion between experimental groups occurred in the subendocardial layers, and macroscopic evidence of necrosis was more widespread after hyperoxia.     

Preconditioning with oxygen attenuates rat renal ischemia-reperfusion injury

BACKGROUND: Short time pretreatment with oxygen is reported to be protective against subsequent ischemia-reperfusion (IR) injury of heart and spinal cord in some animal models. The purpose of this study was to investigate the effects of pre-exposure to hyperoxic environment on rat renal IR injury for the first time. MATERIALS AND METHODS: The effects of 1 h/d pretreatment with oxygen (>or=95%) for 5 days on a right nephrectomized rat model of renal IR injury was investigated by comparing creatinine clearance, fractional excretion of sodium, plasma creatinine, blood urea nitrogen, and histological injury scores among three groups: IR (40 min ischemia-24 h reperfusion), sham (no IR), and hyperoxia (5 days intermittent pretreatment with oxygen + IR). RESULTS: Intermittent pretreatment with oxygen resulted in significant improvement of creatine clearance and fractional excretion of sodium (P 相似文献   

High-intensity aerobic exercise improves diastolic function in coronary artery disease

OBJECTIVE: To study the effect of aerobic treadmill exercise training with different intensity on left ventricular (LV) function in patients with stable coronary artery disease, using Strain Rate- and Tissue Doppler Imaging. DESIGN: Seventeen patients were randomly assigned to either moderate (50-60% of peak oxygen uptake (VO(2peak)) or high intensity exercise (80-90% of VO(2peak)) for 10 weeks. RESULTS: The increase of VO(2peak) was significantly higher (p=0.01) in the high intensity group (17 vs. 8%). Mean LV early diastolic strain rate increased in the high, but not in the moderate, intensity group. For systolic strain rate or mitral annular velocities there were no change after training in either group. CONCLUSIONS: Aerobic treadmill exercise improves early diastolic relaxation in patients with stable coronary artery disease, measured by the mean LV early diastolic strain rate.     

Hyperbaric hyperoxia suppresses growth of Staphylococcus aureus, including methicillin-resistant strains

Purpose. We investigated the effects of increased oxygen tension on the in vitro growth of Staphylococcus aureus (MRSA), methicillin-sensitive Staphylococcus aureus (MSSA), and Escherichia coli (E. coli). Methods. The effects of oxygen tension [normobaric normoxia (21% O₂ at 1 atm), normobaric hyperoxia (100% O₂ at 1 atm), hyperbaric normoxia (21% O₂ at 2 atm), and hyperbaric hyperoxia (100% O₂ at 2 atm) on the in vitro growth of MRSA, MSSA, and E. coli were investigated by population analysis. Results. Compared with normobaric normoxia, a 90-min exposure to hyperbaric hyperoxia significantly inhibited growth of both MRSA (by 25.0 ± 3.0%, mean ± SEM; P < 0.01) and MSSA (by 24.0 ± 3.3%; P < 0.01). Normobaric hyperoxia and hyperbaric normoxia were without effect. In contrast, the growth of E. coli was not affected by any of the above treatments. Conclusion. Our results indicate that the bacterium S. aureus, including resistant strains, is susceptible to oxygen stress. The observation that relatively brief (90-min) treatment with hyperbaric hyperoxia is sufficient to produce significant growth inhibition suggests that hyperbaric hyperoxia may be useful in the treatment of serious staphylococcal infections. Received: March 6, 2000 / Accepted: August 7, 2000     

超声二维应变评价冠状动脉介入治疗后左心室心肌收缩功能

目的应用超声二维应变（2DS）技术观察单支和多支冠状动脉病变心绞痛患者经皮冠状动脉介入治疗（PCI）后左心室局部心肌径向收缩功能改变有无差异。方法将63例心绞痛患者根据冠状动脉造影结果分为单支病变组（n=33）和多支病变组（n=30）,另选志愿者30名作为正常对照组,分别记录PCI术前、术后3个月及正常对照组左心室基底水平、乳头肌水平及心尖部水平18个室壁节段的二维灰阶图像。应用GE Echo PAC软件测量左心室短轴各室壁节段收缩期峰值径向应变。结果与正常对照组比较,单支病变组和多支病变组PCI术前大部分心肌节段和术后3个月部分心肌节段的左心室收缩期短轴峰值径向应变减低（P〈0.05）;单支病变组PCI术后3个月73.51%（136/185）心肌缺血节段恢复到正常水平,与多支病变组54.11%（158/292）差异有统计学意义（P〈0.01）。结论不同冠状动脉病变心绞痛患者PCI术后左心室径向收缩功能改善情况有所不同。     

Lidocaine attenuates hyperoxic lung injury in rabbits

Background: High concentrations of oxygen acute lung injury. Neutrophils are thought to play a pivotal role in the pathogenesis of this lung injury through the release of oxygen radicals, neutral proteases, and lysosomal enzymes. Lidocaine has been shown to inhibit neutrophil function. We examined whether intravenous pretreatment with lidocaine attenuated acute lung injury induced by hyperoxia. Method: Twenty-seven anaesthetized male rabitts were allocated to receive one of three treatments (n = 9 for each group): ventilation with 100% oxygen for 36 h with and without lidocaine treatment, and ventilation with air for 36 h without lidocaine. In the lidocaine-treated group, a single intravenous lidocaine 2 mg/kg was administered immediately after the initiation of exposure to 100% oxygen; Results: Pure oxygen for 36 h caused no significant changes in haemodynamics, lung mechanics, or PaO₂/FiO₂ ratio. However, hyperoxia significantly increased the lung W/D weight ratio, the influx of neutrophils into the lung, and BALF concentrations of C3a, C5a, TNF-α, IL-1β, and albumin. Lidocaine attenuated these increases (W/D ratio: 5.7 vs 5.1, %PMN: 19.2% vs 1.6%, C3a: 62 ng/dl vs 14 ng/dl, C5a: 7.9 ng/dl vs 4.1 ng/dl, TNF-α: 25 fmol/ml vs 2.8 fmol/ml, IL-1β: 36 fmol/ml vs 2.2 fmol/ml, and albumin: 9.5 mg/dl vs 2.8 mg/dl, all: P <0.05). The chemiluminescence was increased in hyperoxic compared with in normoxic rabbits and lidocaine treatment attenuated the increase (opsonized zymosan stiluated: 3.7×10⁶ cpm vs 2.3×10⁶ cpm, P <0.05). Exposure to 100% oxygen caused extensive morphologic lung damage which was lessened by lidocaine (lung injury score (mean): 3 vs 4, P <0.05). Conclusion: These findings suggest that intravenous lidocaine has a prophylatic effect on initial hyperoxic lung injury (pulmonary vascular permeability, histopathological, and biochemical BALF changes) in rabbits. The effects of lidocaine on more severe lung injury (decreased oxygenation) caused by hyperoxia for 72 h deserve further study.     

Combined Strength and Endurance Training in Competitive Swimmers

A combined intervention of strength and endurance training is common practice in elite swimming training, but the scientific evidence is scarce. The influences between strength and endurance training have been investigated in other sports but the findings are scattered. Some state the interventions are negative to each other, some state there is no negative relationship and some find bisected and supplementary benefits from the combination when training is applied appropriately. The aim of this study was to investigate the impact of a combined intervention among competitive swimmers. 20 subjects assigned to a training intervention group (n = 11) or a control group (n = 9) from two different teams completed the study. Anthropometrical data, tethered swimming force, land strength, performance in 50m, 100m and 400m, work economy, peak oxygen uptake, stroke length and stroke rate were investigated in all subjects at pre- and post-test. A combined intervention of maximal strength and high aerobic intensity interval endurance training 2 sessions per week over 11 weeks in addition to regular training were used, while the control group continued regular practice with their respective teams. The intervention group improved land strength, tethered swimming force and 400m freestyle performance more than the control group. The improvement of the 400m was correlated with the improvement of tethered swimming force in the female part of the intervention group. No change occurred in stroke length, stroke rate, performance in 50m or 100m, swimming economy or peak oxygen uptake during swimming. Two weekly dry-land strength training sessions for 11 weeks increase tethered swimming force in competitive swimmers. This increment further improves middle distance swimming performance. 2 weekly sessions of high- intensity interval training does not improve peak oxygen uptake compared with other competitive swimmers.

Key points

• Two weekly sessions of dry land strength training improves the swimming force.
• Two weekly sessions of high-intensity endurance training did not cause improved endurance capacity.
• It may seem that dry land strength training can improve middle distance performance.

Key words: Oxygen consumption, muscle strength, metabolic efficiency     

Hyperoxia and the cerebral hemodynamic responses to moderate hyperventilation

BACKGROUND: A reduction in the arterial partial pressure of CO2 (PaCO2) leads to a rapid reduction in cerebral blood flow (CBF). However, despite continuing hypocapnia there is secondary recovery of CBF over time as a result of increases in lactic acid production. Hyperoxia is thought to modulate the production of lactic acid. This study examined the kinetics of middle cerebral artery flow velocity (MCA FV) reduction during hyperventilation, and its modulation by hyperoxia. METHODS: Cerebral blood flow was assessed using transcranial Doppler ultrasound in nine healthy, awake human volunteers. Subjects were ventilated, via a mouthpiece, to achieve a stable end-tidal CO2 (PETCO2). After a 20-min baseline period the minute volume on the ventilator was passively increased by approximately 20% to reduce PETCO2 by 0.75-1 kPa. After a 10-min stabilization period the new PETCO2 level was maintained at a constant level for 20 min, and MCA FV recovery was measured during this 20-min period. Subjects undertook the protocol breathing air and breathing 100% oxygen. RESULTS: The PETCO2 level was (mean +/- SD) 4.9 +/- 0.4 kPa (normoxia baseline), 4.0 +/- 0.3 kPa (normoxia hyperventilation), 4.6 +/- 0.4 kPa (hyperoxia baseline) and 3.9 +/- 0.4 kPa (hyperoxia hyperventilation). CO2 reactivity was significantly lower with normoxia than hyperoxia (16.5 +/- 3.8 vs. 21.2 +/- 4.6 % kPa-1; P< 0.05). Middle cerebral artery FV recovery was significantly more rapid with normoxia than hyperoxia (0.23 +/- 0.17 vs. 0.08 +/- 0.1 % baseline min-1; P< 0.01). CONCLUSIONS: Our results suggest that cerebral hemodynamic responses to moderate hyperventilation are different in normoxic and hyperoxic conditions. Clinical assessment of CO2 reactivity and CBF recovery during hyperventilation should take the degree of arterial oxygenation into account.     

Hyperoxia-Induced Protection against Rat's Renal Ischemic Damage: Relation to Oxygen Exposure Time

Background. Pre-exposure to hyperoxic gas (≥ 95%) has been shown to protect the heart and central nervous system from ischemia-reperfusion injury. In the present study, we investigated whether oxygen pretreatment induces delayed renal protection in rats. The possible role of some renal antioxidant agents was also investigated. Materials and methods. Adult male Wistar rats were kept in a hyperoxic (HO) (≥ 95% O₂) environment for 0.5 h, 1 h, 2 h, 3 h, 6 h, and 2 h/day for three consecutive days and 4 h/day for six consecutive days, and control group (IR) animals were kept in the cage with no HO, one day before subjecting their kidney to 40 minutes of ischemia and 24h of reperfusion. Renal function was assessed by comparing plasma creatinine (Cr), blood urea nitrogen (BUN), creatinine clearance (CLCr), and fractional excretion of sodium (FENa%). Histopathological injury score was also determined according to the Jablonski method. To examine the antioxidant system induction by hyperoxia, we measured renal catalase and superoxide dismutase activity, and renal glutathione and malondialdehyde content. Results. Our data demonstrated that only in 4 h/day HO for six consecutive days, the renal function tests (Cr, CLCr, BUN, and FENa%) and Jablonski histological injury were better than control group (p < 0.05). The beneficial effect of oxygen pretreatment in this group was associated with increased renal catalase activity compared with those obtained from control group (p < 0.05). Conclusion. The present study demonstrates that repeated exposure to hyperoxic (≥ 95% O₂) environment can reduce subsequent rat's renal ischemia-reperfusion damage. Induction of endogenous antioxidant system may partially explain this beneficial effect of hyperoxic preconditioning.     

Hyperoxia and angiogenesis

We hypothesized that tissue hyperoxia would enhance and hypoxia inhibit neovascularization in a wound model. Therefore, we used female Swiss-Webster mice to examine the influence of differential oxygen treatment on angiogenesis. One milliliter plugs of Matrigel, a mixture of matrix proteins that supports but does not itself elicit angiogenesis, were injected subcutaneously into the mice. Matrigel was used without additive or with added vascular endothelial growth factor (VEGF) or anti-VEGF antibody. Animals were maintained in hypoxic, normoxic, or one of four hyperoxic environments: hypoxia -- 13 percent oxygen at 1 atmosphere absolute (ATA); normoxia -- 21 percent oxygen at 1 ATA; hyperoxia -- (groups a-d) 100 percent oxygen for 90 minutes twice daily at the following pressures: Group a, 1 ATA; Group b, 2 ATA; Group c, 2.5 ATA; Group d, 3.0 ATA. Subcutaneous oxygen tension was measured in all groups. The Matrigel was removed 7 days after implantation. Sections were graded microscopically for the extent of neovascularization. Angiogenesis was significantly greater in all hyperoxic groups and significantly less in the hypoxic group compared with room air-exposed controls. Anti-VEGF antibody abrogated the angiogenic effect of both VEGF and increased oxygen tension. We conclude that angiogenesis is proportional to ambient pO(2) over a wide range. This confirms the clinical impression that angiogenesis requires oxygen. Intermittent oxygen exposure can satisfy the need for oxygen in ischemic tissue.     

Surgical site wound infection,and other postoperative problems after coronary artery bypass grafting in subjects with chronic obstructive pulmonary disease: A meta-analysis

We performed a meta-analysis to evaluate the effect of chronic obstructive pulmonary disease on surgical site wound infection, and other postoperative problems after coronary artery bypass grafting. A systematic literature search up to April 2022 was performed and 37 444 subjects with coronary artery bypass grafting at the baseline of the studies; 4320 of them were with the chronic obstructive pulmonary disease, and 33 124 were without chronic obstructive pulmonary disease. Odds ratio (OR), and mean difference (MD) with 95% confidence intervals (CIs) were calculated to assess the effect of chronic obstructive pulmonary disease on surgical site wound infection, and other postoperative problems after coronary artery bypass grafting using the dichotomous, and contentious methods with a random or fixed-effect model. The chronic obstructive pulmonary disease subjects had a significantly higher surgical site wound infection (OR, 1.27; 95% CI, 1.01-1.60, P = 0.04), respiratory failure (OR, 1.84; 95% CI, 1.55-2.18, P < 0.001), mortality (OR, 1.61; 95% CI, 1.37-1.89, P < 0.001), pneumonia (OR, 2.30; 95% CI, 1.97-2.68, P < 0.001), pleural effusion (OR, 1.78; 95% CI, 1.12-2.83, P = 0.02), stroke (OR, 1.99; 95% CI, 1.17-3.36, P = 0.01), and length of intensive care unit stay (MD, 0.73; 95% CI, 0.19-1.26, P = 0.008) after coronary artery bypass grafting compared with subjects without chronic obstructive pulmonary disease. However, chronic obstructive pulmonary disease subjects did not show any significant difference in length of hospital stay (MD, 0.83; 95% CI, −0.01 to 1.67, P = 0.05), and pneumothorax (OR, 1.59; 95% CI, 0.98-2.59, P = 0.06) after coronary artery bypass grafting compared with subjects without chronic obstructive pulmonary disease. The chronic obstructive pulmonary disease subjects had a significantly higher surgical site wound infection, respiratory failure, mortality, pneumonia, pleural effusion, stroke, and length of intensive care unit stay, and no significant difference in length of hospital stay, and pneumothorax after coronary artery bypass grafting compared with subjects without chronic obstructive pulmonary disease. The analysis of outcomes should be with caution because of the low sample size of 1 out of 11 studies in the meta-analysis and a low number of studies in certain comparisons.     

Short-term inspiratory muscle training potentiates the benefits of aerobic and resistance training in patients undergoing CABG in phase II cardiac rehabilitation program

Objective

To investigate the efficiency of short-term inspiratory muscle training program associated with combined aerobic and resistance exercise on respiratory muscle strength, functional capacity and quality of life in patients who underwent coronary artery bypass and are in the phase II cardiac rehabilitation program.

Methods

A prospective, quasi-experimental study with 24 patients who underwent coronary artery bypass and were randomly assigned to two groups in the Phase II cardiac rehabilitation program: inspiratory muscle training program associated with combined training (aerobic and resistance) group (GCR + IMT, n=12) and combined training with respiratory exercises group (GCR, n=12), over a period of 12 weeks, with two sessions per week. Before and after intervention, the following measurements were obtained: maximal inspiratory and expiratory pressures (PImax and PEmax), peak oxygen consumption (peak VO₂) and quality of life scores. Data were compared between pre- and post-intervention at baseline and the variation between the pre- and post-phase II cardiac rehabilitation program using the Student''s t-test, except the categorical variables, which were compared using the Chi-square test. Values of P<0.05 were considered statistically significant.

Results

Compared to GCR, the GCR + IMT group showed larger increments in PImax (P<0.001), PEmax (P<0.001), peak VO₂ (P<0.001) and quality of life scores (P<0.001).

Conclusion

The present study demonstrated that the addition of inspiratory muscle training, even when applied for a short period, may potentiate the effects of combined aerobic and resistance training, becoming a simple and inexpensive strategy for patients who underwent coronary artery bypass and are in phase II cardiac rehabilitation.     

No effect of group-based aerobic interval training on N-terminal pro- B-type natriuretic peptide levels in patients with chronic heart failure

Abstract

Objectives. Exercise training might improve cardiac function as well as functional capacity in patients with chronic heart failure (CHF). N-terminal pro-B-type natriuretic peptide (NT pro-BNP), is associated with the severity of the disease, and has been reported to be an independent predictor of outcome in CHF. We evaluated the effect of a four months group-based aerobic interval training program on circulating levels of NT pro-BNP in patients with CHF. We have previously reported improved functional capacity in 80 patients after exercise in this exercise program. Methods. Seventy-eight patients with stable CHF (21% women; 70±8 years; left ventricular ejection fraction 30±8.6%) on optimal medical treatment were randomized either to interval training (n=39), or to a control group (n=39). Circulating levels of NT pro-BNP, a six minute walk test (6MWT) and cycle ergometer test were evaluated at baseline, post exercise, and further after 12 months. Results. There were no significant differences in NT pro-BNP levels from baseline to either post exercise or long-term follow-up between or within the groups. Inverse correlations were observed between NT pro-BNP and 6MWT (r=?0.24, p=0.035) and cycle exercise time (r=?0.48, p<0.001) at baseline. But no significant correlations were observed between change in NT pro-BNP and change in functional capacity (6MWT; r=0.12, p=0.33, cycle exercise time; r=0.04, p=0.72). Conclusion. No significant changes in NT pro-BNP levels were observed after interval training, despite significant improvement of functional capacity.     

Effects of vitamin D supplementation as an adjuvant therapy in coronary artery disease patients*

Objectives: Low vitamin D status has been shown to be associated with coronary artery disease. We planned to research the effects of vitamin D₃ supplementation on the severity of coronary artery disease. Design: We investigated the effect of 0.5 μg vitamin D₃ per day in a randomized, placebo-controlled, double-blind study in 90 stable coronary artery disease patients residing in Beijing. Coronary angiography was performed before and after 6 months of treatment that took place between January and June. 25-Hydroxyvitamin D was measured by chemiluminescence assay. Coronary artery disease severity was assessed by using the SYNTAX scores. Results: In vitamin D supplementation group, there was a significant increase in mean 25-hydroxyvitamin D levels from baseline (19.9?±?9.8 ng/ml) to 6 months (35.8?±?12.1 ng/ml; p?<?0.001). At 6 months, the primary end point, a difference in the fall of SYNTAX score between the groups was ?2.5 (95% CI ?5.1 to ?0.5; p?<?0.001) under intention to treat analysis. Compared with the control group, patients treated with vitamin D₃ also had greater decreases in high sensitivity C-reactive protein and renin-angiotensin system activity (p?<?0.05). Conclusions: Vitamin D supplementation has beneficial effects on coronary artery disease; it can be an adjuvant therapy for patients with coronary artery disease.     

Survival difference between coronary bypass surgery and percutaneous coronary intervention

Abstract

Objectives. To assess whether the previously observed lower death rate with coronary artery bypass surgery compared with percutaneous coronary intervention in subsets of patients with coronary artery disease persists in more recent years. Design. Retrospective study from Feiring Heart Clinic database of survival in 17739 patients followed for 5 years after coronary revascularization. The cohorts treated in 1999–2005 and 2006–2011 were compared using Cox regression and propensity score analyses. Results. Cox regression and propensity score analyses revealed no difference in survival in either time period in one- and two-vessel diseases. In three-vessel disease, the hazard ratios between bypass surgery and percutaneous intervention were 0.62 (95% confidence interval [CI]: 0.53–0.71, p <0.001) and 0.59 (95% CI: 0.47–0.73, p < 0.001), respectively, in the two time periods, indicating persistent higher survival with bypass surgery. Conclusions. The previously observed lower death rate of coronary artery bypass surgery compared with percutaneous intervention in patients with three-vessel disease is persistent in more recent years and indicates that bypass surgery still should be the standard treatment for these patients.     

Off-pump coronary artery bypass grafting in octogenarians

Objectives: Off-pump coronary artery bypass grafting (CABG) has become accepted for myocardial revascularization because it reduces perioperative morbidity. We assessed the safety and efficacy of bypass surgery on the beating heart in elderly patients. Methods: Off-pump CABG was done in 25 patients aged 80 years or older between February 1996 and February 2001. We retrospectively compared clinical results for these patients to those of 18 consecutive age-matched patients undergoing on-pump CABG during the same period. Results: Mean patient age in both groups was similar −82.2±2.3 years in the off-pump group vs 81.9±2.0 years in the on-pump group (p=0.66). Preoperative risk was similar in both groups, but significantly more patients in the on-pump group had triple-vessel disease. Distal anastomoses were significantly fewer in the off-pump group than in the on-pump group at 2.0±1.0 vs 2.8±0.5 (p<0.01). The off-pump group had a shorter postoperative ventilation −13.4±17.2 hours vs 45.2±52.8 hours (p<0.05)—, and less blood transfused −16% vs 89% (p<0.01)—than the on-pump group. Mean postoperative hospitalization and intensive care unit stay were 18.6 days and 3.2 days in the off-pump group, versus 37.1 days and 9.4 days in the on-pump group (p<0.05). No difference was seen in the incidence of major postoperative complications between groups. No hospital deaths occurred in the off-pump group. Conclusion: Off-pump CABG is thus a safe and effective for myocardial revascularization in the elderly.     

Effect of training intensity on physical capacity, lipid profile and insulin sensitivity in early rehabilitation of spinal cord injured individuals

STUDY DESIGN: Pre-post training intervention. OBJECTIVES: To evaluate the effect of training intensity on physical capacity, lipid profile and insulin sensitivity in early rehabilitation of spinal cord injured (SCI) patients, and to assess the correlation between peak aerobic capacity (VO(2Peak)) and insulin sensitivity. SETTING: Spinal Cord Rehabilitation Unit, Sunnaas Hospital, Nesoddtangen, Norway. METHOD: Six recently injured SCI individuals participated in the arm training intervention and were randomly admitted to a high-intensity (HI; 70-80% heart rate reserve (HRR)) and low-intensity (LI; 40-50% HRR) group. The 1 h interval training consisted of 3 min exercise bouts interspersed with 2 min of rest, three times a week for 8 weeks. In addition, a correlation coefficient was obtained between VO(2Peak) and insulin sensitivity in 11 SCI patients. RESULTS: The 8-week training program resulted in a significant increase in VO(2Peak) and maximal power output (PO(Max)) for the group as a whole (P<0.05). VO(2Peak) increased significantly more and total cholesterol/high-density lipoprotein cholesterol (TC/HDL-C) ratio and triglycerids decreased significantly more in the HI group than in the LI group (P=0.05). Training-induced changes in insulin sensitivity were significantly different between the groups (P=0.05), which was due to a nonsignificant decline in insulin sensitivity in the HI group and a nonsignificant improvement in the LI group. A significant positive correlation was found between VO(2peak) and insulin sensitivity (r=0.68, P=0.02). CONCLUSION: The interval arm training protocol as used in the present study enables recently injured SCI patients to do substantial work at a relatively high intensity. Results indicate that improvements in physical capacity and lipid profile were more pronounced in response to high-intensity training. The significant correlation between maximal oxygen consumption and insulin sensitivity indicates that, as in the able-bodied population, peak aerobic capacity is a predictive value with regard to insulin sensitivity in SCI. Future studies with larger groups assessing the role of exercise intensity on insulin sensitivity in SCI are suggested.     

Cardiopulmonary exercise testing in severe osteoarthritis: a crossover comparison of four exercise modalities*

Cardiopulmonary exercise testing is performed increasingly for cardiorespiratory fitness assessment and pre-operative risk stratification. Lower limb osteoarthritis is a common comorbidity in surgical patients, meaning traditional cycle ergometry-based cardiopulmonary exercise testing is difficult. The purpose of this study was to compare cardiopulmonary exercise testing variables and subjective responses in four different exercise modalities. In this crossover study, 15 patients with osteoarthritis scheduled for total hip or knee arthroplasty (mean (SD) age 68 (7) years; body mass index 31.4 (4.1) kg.m^-2) completed cardiopulmonary exercise testing on a treadmill, elliptical cross-trainer, cycle and arm ergometer. Mean (SD) peak oxygen consumption was 20-30% greater on the lower limb modalities (treadmill 21.5 (4.6) (p < 0.001); elliptical cross-trainer (21.2 (4.1) (p < 0.001); and cycle ergometer (19.4 (4.2) ml.min⁻¹.kg⁻¹ (p = 0.001), respectively) than on the arm ergometer (15.7 (3.7) ml.min^-1.kg^-1). Anaerobic threshold was 25-50% greater on the lower limb modalities (treadmill 13.5 (3.1) (p < 0.001); elliptical cross-trainer 14.6 (3.0) (p < 0.001); and cycle ergometer 10.7 (2.9) (p = 0.003)) compared with the arm ergometer (8.4 (1.7) ml.min⁻¹.kg⁻¹). The median (95%CI) difference between pre-exercise and peak-exercise pain scores was greater for tests on the treadmill (2.0 (0.0-5.0) (p = 0.001); elliptical cross-trainer (3.0 (2.0-4.0) (p = 0.001); and cycle ergometer (3.0 (1.0-5.0) (p = 0.001)), compared with the arm ergometer (0.0 (0.0-1.0) (p = 0.406)). Despite greater peak exercise pain, cardiopulmonary exercise testing modalities utilising the lower limbs affected by osteoarthritis elicited higher peak oxygen consumption and anaerobic threshold values compared with arm ergometry.