Clinical evaluation of leukocyte-depleted blood cardioplegia for pediatric open heart operation

Background. Blood cardioplegia (BCP) is widely used for myocardial protection during open heart operation. However, BCP may have a chance to induce neutrophil-mediated myocardial injury during aortic cross-clamping. We clinically evaluated the myocardial protective effect of leukocyte-depleted blood cardioplegia (LDBCP) for initial and intermittent BCP administration in pediatric patients.

Methods. Fifty patients undergoing open heart operation for congenital heart disease between January 1997 and March 1999 were reviewed. Twenty-five were administered LDBCP for myocardial protection during ischemic periods (LDBCP group), and the remaining 25 were given BCP without leukocyte depletion (BCP group).

Results. The difference in plasma concentrations of malondialdehyde between coronary sinus effluent blood and arterial blood just after reperfusion in the LDBCP group (1.68 ± 0.56 μmol/L) was significantly lower than that in the BCP group (2.35 ± 0.62 μmol/L; p < 0.01). The LDBCP group showed significantly lower plasma concentrations of human heart fatty acid-binding protein at 50 minutes after reperfusion (LDBCP group, 103.5 ± 38.7 IU/L; BCP group, 144.8 ± 48.8 IU/L; p < 0.01) and the peak value of creatine kinase-MB during the first 24 postoperative hours (LDBCP group, 17.0 ± 8.5 IU/L; BCP group, 26.0 ± 11.6 IU/L; p < 0.01) than did the BCP group. The maximum dose of catecholamine was significantly smaller in the LDBCP group (LDBCP group, 3.20 ± 2.18 μg · kg⁻¹ · min⁻¹; BCP group, 5.60 ± 2.83 μg · kg⁻¹· min⁻¹; p < 0.01).

Conclusions. These results suggest the usefulness of LDBCP for protection from the myocardial injury that can be induced by BCP administration during aortic cross-clamping.     

SMA circuits reduce platelet consumption and platelet factor release during cardiac surgery

Background. Platelet count and function are particularly damaged by cardiopulmonary bypass (CPB). This study evaluated the effects of a novel CPB circuit in terms of platelet count and activation, and postoperative need for blood products.

Methods. One hundred patients undergoing coronary grafting were randomized in two groups: control group (n = 50) and test group (n = 50, surface modifying additives circuit, SMA group). Blood samples were taken before, during, and after CPB. Postoperative blood loss, number of transfused blood products, and postoperative variables were recorded.

Results. The platelet count decreased less in the SMA group compared to the control group (end of CPB: respectively, 165 ± 9 × 10³/mm³ vs 137 ± 8 × 10³/mm³; p < 0.01). This was paralleled by a reduction in β-thromboglobulin plasma levels in the SMA group. There was a trend to decreased blood loss in the SMA group, but the difference was significant only in patients taking aspirin preoperatively (p < 0.05). In the SMA group nearly 50% less fresh frozen plasma and platelet units were administered (p < 0.01). No operative deaths were observed.

Conclusions. The use of circuits with surface additives is clinically safe, preserves platelet levels, and attenuates platelet activation. This may lead to a reduced need for blood products.     

Dose-response effect of short-term calcitriol treatment on bone and mineral metabolism in normal males

To evaluate the effects of short-term treatment with calcitriol on biochemical markers of calcium and bone metabolism, 36 normal male volunteers (aged 21–54 years) were randomized to oral treatment for 7 days with either (A) calcitriol, 1 μg twice daily, (B) calcitrol, 0.5 μg twice daily, or (C) placebo twice daily. Serum calcium increased slightly in a dose-dependent manner (maximal increase 2.5%, p < 0.05) followed by a heavy increase in both 24 h (max. 156.1%, p < 0.001) and fasting urinary calcium excretion (max. 123.1%, p < 0.001), and a striking reduction in serum PTH (max. −43.1%, p < 0.001). Biochemical markers of osteoblast activity and bone formation increased immediately in a dose-dependent manner [serum osteocalcin (max. 37.8%, p < 0.03) and serum procollagen type I C-terminal propeptide (PICP) (max. 26.0%, p < 0.05)], whereas there was no effect on serum bone alkaline phosphatase. Calcitriol treatment had no effect on biochemical markers of bone resorption [serum C-terminal telopeptide of type I collagen (ICTP) and fasting urinary excretion of hydroxyproline/creatinine (OHP)]. Extraosseous collagen matrix synthesis was not affected evaluated by serum procollagen type III N-terminal propeptide (PIIINP). In the follow-up period (15 weeks) no unequivocal changes were observed. The fast and protracted increase in biochemical markers of osteoblast activity and bone formation, without affecting bone resorption and extraosseous connective tissue metabolism points toward a selective effect of calcitriol on bone matrix formation.     

Anaphylactic/anaphylactoid reactions during cardiac surgery

Over a 12-month period, 1,743 patients were retrospectively evaluated for anaphylactic/anaphylactoid reactions during cardiac surgery. Reactions to protamine, vancomycin, blood, and metocurine were observed in eight patients (0.46%). Base-line to reaction mean arterial pressures decreased from 81 ± 9 mmHg to 50 ± 7 mmHg (mean ± SD; p < 0.001), cardiac output increased from 4.6 ± 0.6 L/min to 6.5 ± 1.2 L/min (p < 0.005), stroke volume increased from 49 ± 11 to 83 ± 22 ml/beat (p < 0.02), and systemic vascular resistance decreased from 1,294 ± 137 to 563 ± 127 dyne/sec/cm⁻⁵ (p < 0.001). Two patients developed pulmonary artery hypertension, while only one patient developed bronchospasm. Initial hypertnsion during anaphylacticlanaphylactoid reactions is due to decreased systemic vascular resistance, not myocardial depression.     

Effect of growth hormone therapy in burn patients on conservative treatment

Evaluation of growth hormone therapy in burns is limited and none is reported from developing countries where burns still carry high mortality. We analysed serial observations on the clinical and biochemical profiles in 13 patients with second and third degree burns who received recombinant human growth hormone (rhGH) (0.5 IU/kg body wt) for 2 weeks in addition to standard conservative treatment and in 9 patients who were managed with standard conservative treatment only. The two groups of patients had burns, comparable in extent and severity. Additional rhGH treatment resulted in improved wound healing (p<0.001), delayed separation of eschars (p<0.01), increase in haemoglobin (p<0.05), serum albumin (p<0.01), calcium (p<0.05), phosphorus (p<0.001), glomerular filtration rate (p<0.05) and 7 fold elevation in IGF-1. Also, a reduction in weight loss (p<0.01), nitrogen production rate (p<0.05), catabolic index (p<0.01), duration of sepsis (p<0.01) and hospital stay by 40% (p<0.01) was noted with rhGH therapy. Transient hypercalcemia (3 patients), albuminuria (2 patients) and elevated blood glucose (one patient) were noted in the rhGH treated group not necessitating any specific therapy. Mortality in rhGH treatment group was 8.3% compared to 44.5% in the “no rhGH” treatment group. These observations suggest significant benefits of short term rhGH treatment in burn patients on conservative management.     

Epoxyeicosatrienoic acids (EET(11,12)) may partially restore endothelium-derived hyperpolarizing factor-mediated function in coronary microarteries.

Background. Endothelial cells derive nitric oxide, prostacyclin, and endothelium-derived hyperpolarizing factor (EDHF). The cytochrome P-450–monooxygenase metabolites of arachidonic acid (epoxyeicosatrienoic acids [EETs]) have been suggested to be EDHF. This study was designed to examine the effect of EET_11,12 with regard to the possibility of restoring EDHF function when added into hyperkalemic cardioplegic solution.

Methods. Porcine coronary microartery rings were studied in a myograph. In groups 1 and 2, paired arteries were incubated in either hyperkalemic solution (K⁺ 20 mmol/L) or Krebs’ solution (control). In group 3, the paired arteries were incubated in hyperkalemia plus EET_11,12 (1 × 10^−6.5 mol/L) or hyperkalemia alone (control) at 37°C for 1 hour, followed by Krebs’ washout and then precontracted with 1 × 10^−8.5 mol/L U46619. The EDHF-mediated relaxation to EET_11,12 (group 1) or bradykinin (groups 2 and 3) was studied in the presence of N^G-nitro-l-arginine, indomethacin, and oxyhemoglobin.

Results. After exposure to hyperkalemia, the EDHF-mediated maximal relaxation by bradykinin (72.5% ± 7.8% versus 41.6% ± 10.6%; p < 0.05), but not by EET_11,12 (18.4% ± 3.3% versus 25.1% ± 4.9%; p > 0.05) was significantly reduced. Incubation with EET_11,12 partially restored EDHF function (33.3% ± 9.5% versus 62.0% ± 8.5%; p < 0.05).

Conclusions. In coronary microarteries, hyperkalemia impairs EDHF-mediated relaxation, and EET_11,12 may partially mimic the EDHF function. Addition of EET_11,12 into cardioplegic solution may partially restore EDHF-mediated function reduced by exposure to hyperkalemia.     

Right internal thoracic artery through the transverse sinus in myocardial revascularization

Background. A major concern in evaluating dynamic cardiomyoplasty has been whether the synchronous stimulation of latissimus dorsi muscle is essential for benefit or not. We studied 10 patients to determine the efficacy of the systolic augmentation generated by the synchronous electrical stimulation of the latissimus dorsi muscle.

Methods. Left ventricular ejection fraction, end-systolic and end-diastolic volume indexes, and stroke volume index obtained during resting, peak exercise, and recovery periods (“on” values) were compared with those obtained 1 week after cessation of electrical stimulus (“off” values). Double product and estimated total body oxygen consumption at peak exercise were also calculated and compared.

Results. Higher ejection fractions (0.36 ± 0.07 versus 0.33 ± 0.06 at rest, 0.40 ± 0.07 versus 0.33 ± 0.07 peak exercise, and 0.37 ± 0.06 versus 0.31 ± 0.06 at recovery) and lower end-systolic volume indexes with relatively constant end-diastolic volume indexes were observed with the cardiomyostimulator on. Further, exercise response was better with the cardiomyostimulator on. Double product indirectly reflected better myocardial oxygen supply/demand ratio when on at peak exercise (17 ± 2.2 mm Hg × beats/min × 10⁻³ for on versus 19 ± 2.6 mm Hg × beats/min × 10⁻³ for off). Estimated total body oxygen consumption was improved at peak exercise when the cardiomyostimulator was functional (12 ± 2.7 mL · kg⁻¹ · min⁻¹ versus 11 ± 2.6 mL · kg⁻¹ · min⁻¹).

Conclusions. Current data suggest a true systolic assist during synchronous contractions of the latissimus dorsi muscle. It is thought, therefore, that synchronous electrical stimulation is essential for maximum benefit and all the beneficial effect of cardiomyoplasty certainly cannot be attributed to simple wrapping itself.     

Serum vitamin D metabolites and nuclear uptake of (3H)-1,25-dihydroxyvitamin D3 in monocytes from patients with autosomal dominant osteopetrosis: a study of two radiological types

The nuclear uptake of (³H)-1,25 dihydroxyvitamin D₃ in freshly isolated human monocytes and the serum levels of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D were investigated in 13 patients with autosomal dominant osteopetrosis and in sex- and age-matched controls. Seven patients had type I osteopetrosis characterized by diffuse, symmetrical osteosclerosis with pronounced sclerosis of the skull and increased thickness of the cranial vault. The other six patients had type II with “Rugger Jersey Spine” and “endobones” as characteristic findings. In type I osteopetrosis the serum 1,25-dihydroxy vitamin D was significantly reduced (p < 0.05), whereas serum 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D receptor binding were normal. In type II osteopetrosis the serum vitamin D metabolites were normal, as was the maximal binding capacity (Bmax) of 1,25-dihydroxyvitamin D to the nuclear receptor. The dissociation constant (Kd), however, was significantly increased (p < 0.01) indicating a modest resistance to 1,25-dihydroxyvitamin D. It is concluded that a general end-organ resistance to 1,25-dihydroxyvitamin D at the receptor level does not exist in type I osteopetrosis, but may contribute to some of the radiological and biochemical findings in type II.     

The response of rat tibiae to incremental bouts of mechanical loading: A quantum concept for bone formation

To investigate the minimum number of loading bouts necessary to produce new lamellar or woven bone formation, and the time required for its initiation, bone formation was measured in 32 retired breeder female Sprague-Dawley rats following one, two, three, or five bouts of applied loading. Bending forces of 54 N were applied to right tibiae using a four-point loading apparatus, and left tibiae served as contralateral controls. Loading was applied as a sine wave with a frequency of 2 Hz for 18 s (36 cycles) per loading bout. Rats were injected with alizarin on day 1 and calcein on days 5 and 12, and were killed on day 19. One bout of loading was sufficient to increase the periosteal woven bone surface (Wb.Pm/B.Pm) from 0% to 40% (p < 0.01), and to 80% after five bouts of loading (p < 0.01), with a dose-response relationship for increases in Wb.Pm/B.Pm (p < 0.0001), mineral apposition rate (Wb.AR; p = 0.002), and bone formation rate (Wb.BFR/BS; p = 0.0001). In the first labeling period (days 1–5), the endocortical lamellar bone forming surface (BS_f/BS) was increased slightly (p < 0.05), but no significant differences were shown for BFR/BS or MAR. From days 5 to 19, right tibiae showed a dose-response increase in BFR/BS (p = 0.002) and BS_f/BS (p = 0.008), but not MAR. These results are consistent with a “quantum” model of bone formation such that a “quantum” of bone cells is activated in response to the loading bout and the strain magnitude dictate the size or microstructural organization of a given packet of new bone. Conversely, the distributed nature of loading may define the recruitment, rather than size, of new packets of bone.     

Sex and age distribution of 1,25(OH)2D3 receptors in peripheral blood mononuclear cells from normal human subjects

Specific receptors for 1,25 Dihydroxyvitamin D₃ have been described in human peripheral blood mononuclear cells (PBMC). We have tried to find out whether these receptors could show any difference in sex or age distribution. Twenty two healthy men aged 21–66 yr (mean ± SD 41.0 ± 13.6) and nineteen healthy women aged 22–60 yr (38.9 ± 13.9) have been studied. The mean dissociation constant (Kd) was similar in both sexes (1.35 ± 0.70 × 10⁻¹⁰M in males, 1.13 ± 0.66 × 10⁻¹⁰M in females), but the concentration of binding sites (Nmax) was significantly lower in females (2.32 ± 0.92 fmol/10⁷ PBMC vs 4.43 ± 1.38 fmol/10⁷ PBMC in males; p = 0.0001). Neither Kd nor Nmax were significantly correlated with age. No difference was found between pre and postmenopausal women. Further studies are needed to elucidate if this sex difference in PBMC receptors for 1,25 Dihydroxy vitamin D₃ is of any pathophysiological relevance.     

A Pilot Study of Body Composition and Bone Mineral Density in Healthy Men From Argentina

A precise assessment of bone mineral density (BMD) and body composition can be performed using dual-energy X-ray absorptiometry (DXA). Values of body composition for males would be useful to evaluate the occurrence of alterations in body composition in a number of diseases. The objectives of this study were to establish BMD and body composition values in healthy men and to analyze age-related changes. BMD and body composition of total body and subareas were determined in 116 healthy men (aged 20–79 yr) using DXA. Comparison between 20–29- and 70–79-yr-old men showed that older subjects were shorter (p < 0.03), and had a higher body mass index (p < 0.01). Fat mass increased (+46.7%; p < 0.001) especially in the trunk. Lean mass (LM) decreased (−9.4%; p < 0.05) mainly in the arms and legs. Bone mineral content (BMC) and BMD decreased (−15.3% [p < 0.001], −6.3% [p < 0.05], respectively). Correlation was observed between BMC and LM (r = 0.7, p < 0.01). Values of BMD and body composition in healthy men were obtained. A relation was observed between bone mass and body composition, suggesting that the age-related decrease in LM may be associated to bone mass loss. Further studies should be conducted to elucidate the role of body composition in the occurrence of osteoporosis in men.     

Low-megahertz ultrasonic properties of bovine cancellous bone

Ultrasound offers a noninvasive means to detect changes that occur to the density of cancellous bone as a result of degenerative diseases such as osteoporosis. Techniques based on the velocity and frequency dependence of attenuation of ultrasonic pulses propagated through cancellous bone have proven sensitive to bone density. Most previous studies have investigated these two parameters in the frequency range of 0.1–1.0 MHz. The present study had two goals. The first was to measure three ultrasonic parameters: longitudinal mode velocity; broadband ultrasonic attenuation (BUA); and apparent integrated backscatter (AIB), at higher frequencies using a broadband 2.25 MHz measurement system. The second goal was to assess the dependence of these parameters on bone density. Twenty-one specimens of cancellous bone acquired from the proximal end of four bovine tibiae were investigated in this study. The apparent density of the specimens (determined with the bone marrow removed and the specimens thoroughly dry) ranged between 0.3 and 0.9 g/cm³. Ultrasonic measurements were performed along three mutually perpendicular directions corresponding to the anteroposterior (AP), mediolateral (ML), and superoinferior (SI) axes of the tibia. A linear regression was used to analyze the results of these measurements as a function of apparent density. Velocity demonstrated a highly significant linear increase with density for all three directions (AP: p < 0.001; ML: p < 0.001; SI: p < 0.01). AIB decreased with density in all three directions; however, only the ML and SI directions demonstrated a significant linear correlation (AP: p = n.s.; ML: p < 0.05; SI: p < 0.05). In the frequency range 0.5–1.0 MHz, BUA exhibited a significant linear increase in the AP and ML directions, but not the SI direction (AP: p < 0.05; ML: p < 0.01; SI: p = n.s.). In contrast, in the frequency range 1.0–2.0 MHz, BUA exhibited a highly significant increase with density in the SI direction, but no significant change in the AP and ML directions (AP: p = n.s., ML: p = n.s., SI: p < 0.001).     

High prevalence of vitamin D deficiency and reduced bone mass in elderly women with Alzheimer’s disease

Patients with Alzheimer’s disease (AD) are at increased risk for falls and hip fractures. To better understand causes and prevention, we measured bone mineral density (BMD) in the second metacarpals of 46 ambulatory elderly women with AD and analyzed its relation to serum biochemical indices, sunlight exposure, and vitamin D intake. BMD was significantly less than in age-matched controls. In 26% of AD patients, the serum 25-hydroxyvitamin D (25-OHD) concentration was at a deficient level (5–10 ng/mL), and in 54% it was at an osteomalacic level (<5 ng/mL). Concentrations of ionized calcium were significantly lower in patients. Conversely, concentrations of serum bone Gla-protein and urinary hydroxyproline in patients were significantly higher than in controls. BMD correlated positively with 25-OHD concentration (p = 0.0041) and negatively with parathyroid hormone (PTH) concentration (p = 0.0022). PTH was higher in patients than in controls, and correlated negatively with 25-OHD (p < 0.0001). Many AD patients were sunlight-deprived and consumed less than 100 IU of vitamin D per day. We concluded that vitamin D deficiency due to sunlight deprivation and malnutrition, together with compensatory hyperparathyroidism, contributes significantly to reduced BMD in AD patients. Low BMD increases risk of hip fractures in patients with AD, but may be improved by vitamin D supplementation.     

Early response in biochemical markers predicts long-term response in bone mass during hormone replacement therapy in early postmenopausal women

Based on data from 153 early postmenopausal women who completed a double-blind, randomized 3 year study of graded hormone replacement therapy (HRT) doses or placebo, we investigated the value of bone markers to predict prevention of bone loss. Absolute values of serum and urinary CrossLaps (S-CTX and U-CTX) after 2 weeks of treatment were significantly correlated to 3 year bone mass response (r = −0.28/−0.35; p < 0.001). These associations were fully expressed at 6 months (r = −0.61/−0.64; p < 0.001). Receiver operating characteristic analyses revealed that the predictive capacity of one measurement of a resorption marker after 6 months’ treatment performed similarly as assessment of hip bone mass over 3 years in predicting preservation of spinal bone mass over 3 years. Comparable results were obtained using percent change from baseline in resorption markers at both 6 and 12 months, whereas for formation markers percent change was superior to absolute value at 6 months but not at 12 months. Values of accuracy for S-CTX for a cutoff of 1881 pmol/L at 6 months were 85.2% (sensitivity), 74.3% (specificity), 90.5% (positive predictive value), and 63.4% (negative predictive value); U-CTX performed similarly, whereas the values for the formation markers were slightly lower. A cutoff for S-CTX of 1245 pmol/L eliminated false-positive individuals (those who had a decrease below the cutoff but lost bone). In the false-negative group, which was composed of individuals whose S-CTX did not decrease below the cutoff but had preserved bone mass, S-CTX was significantly associated with spinal bone mass response (r = −0.41; p < 0.01), indicating these women had been treated with a dose that was not at its optimum for their individual bone turnover. For this cutoff, the values were 49.5% (sensitivity), 97.1% (specificity), 98% (positive predictive value), and 40% (negative predictive value). In conclusion, early bone marker measurements predict long-term preservation of bone mass during HRT. Resorption markers seem superior to formation markers, which reflects that the primary effect of HRT is on bone resorption. A strategy with two cutoff levels may optimize the use of bone markers to predict bone mass response. Whether resorption markers can be used to guide individualized treatment remains to be investigated.     

Heat shock improves recovery and provides protection against global ischemia after hypothermic storage

Background. Improved methods of donor heart preparation before preservation could allow for prolonged storage and permit remote procurement of these organs. Previous studies have shown that overexpression of heat-shock protein 72 provides protection against ischemic cardiac damage. We sought to determine whether rats subjected to heat stress with only 6-hour recovery could acquire protection to a subsequent heart storage for 12 hours at 4°C.

Methods. Three groups of animals (n = 10 each) were studied: control, sham-treated, and heat-shocked rats (whole-body hyperthermia 42°C for 15 minutes). After 12-hour cold ischemia hearts were reperfused on a Langendorff column. To confirm any differences in functional recovery, hearts were then subjected to an additional 15-minute period of warm global ischemia after which function and lactate dehydrogenase enzyme leakage were measured.

Results. Heat-shocked animals showed marked improvements compared with controls in left ventricular developed pressure (63 ± 4 mm Hg versus 44 ± 4 mm Hg, p < 0.05) heart rate × developed pressure (13,883 ± 1,174 beats per minute × mm Hg versus 8,492 ± 1,564 beats per minute × mm Hg, p < 0.05), rate of ventricular pressure increase (1,912 ± 112 mm Hg/second versus 1,215 ± 162 mm Hg/second, p < 0.005), rate of ventricular pressure decrease (1,258 ± 89 mm Hg/second versus 774 ± 106 mm Hg/second, p < 0.005). Diastolic compliance and lactate dehydrogenase release were improved in heat-shocked animals compared with controls and sham-treated animals. Differences between heat-shocked animals and control or sham-treated animals were further increased after the additional 15-minute period of warm ischemia. Western blot experiments confirmed increased heat-shock protein 72 levels in heat-shocked animals (> threefold) compared with sham-treated animals and controls.

Conclusions. Heat shock 6 hours before heart removal resulted in marked expression of heat-shock protein 72 and protected isolated rat hearts by increased functional recovery and decreased cellular necrosis after 12-hour cold ischemia in a protocol mimicking that of heart preservation for transplantation. Protection was further confirmed after an additional 15-minute period of warm ischemia.     

Preliminary experience with the St. Jude Medical Regent mechanical heart valve in the aortic position: early in vivo hemodynamic results

Background. The St. Jude Medical Regent is a new generation mechanical aortic valve.

Methods. Between March 2000 and July 2001, this valve was implanted in the aortic position in 40 patients (21 men; mean age 59.1 ± 9.0 years). Preoperatively, 24 patients (60%) were in New York Heart Association functional class III or IV. Eighteen patients (45%) underwent associated procedures. Mean valve size was 21.4 ± 2.4 mm. The mean duration of follow-up was 8.5 ± 4.5 months (range, 1 to 16 months).

Results. There were no operative deaths. Early complications included one reoperation for bleeding and one transient low output syndrome. Valve replacement was followed by a significant reduction in mean and peak transaortic gradients over time (p < 0.001) and analysis of variance failed to demonstrate statistical differences between valve size over time (p = not significant). A significant reduction in left ventricular hypertrophy occurred over time (p = 0.01) in all valve sizes (p = not significant between groups): baseline left ventricular mass index was 194 g/cm²; it reduced by 22 g/cm² (p = 0.006) at discharge. Left ventricular mass index decreased from 172 ± 55 g/cm² to 156 ± 44 g/cm² (p = 0.03) from discharge to 2 months. Further reductions were not significant. Relative wall thickness decreased from 0.57 ± 0.13 preoperatively to 0.42 ± 0.06 at discharge (p = 0.001), and again at 2 months (−0.2; p = not significant), and at 1 year (−0.02; p = not significant).

Conclusions. The early experience with the St. Jude Medical Regent valve has been satisfactory.     

Emergency coronary artery bypass grafting after failed coronary angioplasty: what has changed in a decade?

Background. We assessed the impact of patient and procedural characteristics on the outcome after emergency coronary artery bypass grafting (CABG) for failed percutaneous transluminal coronary angioplasty (PTCA) and temporal changes in these factors.

Methods. Patients who underwent PTCA and subsequent emergency CABG were identified from the databases of the Departments of Cardiology and Cardiothoracic Surgery.

Results. Two periods of clinical practice were compared. In 1989 to 1993, 2,880 PTCAs were performed, 64 patients underwent emergency CABG (2.3%), and 7 patients died (10.9%). During 1994 to 1998, 46 patients of 3,801 PTCAs underwent emergency CABG (1.2%, p < 0.01), and 7 patients died (15.2%, NS). The average rate of stenting increased from 0.8% to 24% in 1994 to 1998 as well as the frequency of arterial bypass grafts (0% vs 39%). In the latter period, patients were older, were more often females, had more cardiovascular risk factors, a higher Cleveland score (each p < 0.05), and suffered more often from periprocedural myocardial infarctions (p < 0.001) and nonfatal periprocedural complications (p < 0.01).

Conclusions. Although the frequency of emergency CABG after failed PTCA declined, perioperative mortality tended to increase according to an unfavorable shift in patient risk factors and morbidity.     

The efficacy of intraoperative internal intercostal nerve block during video-assisted thoracic surgery on postoperative pain

Background. Video-assisted thoracic surgery (VATS) is widely used for many thoracic surgical procedures. Postoperative pain is less after VATS than after conventional thoracic surgery, but is still significant. The objective of this study was to assess the efficacy of thoracoscopic, internal intercostal nerve block in alleviating immediate postoperative pain.

Methods. Thirty-two patients underwent VATS bilateral sympathectomy for the treatment of hyperhidrosis. The patients were randomly divided into two groups with similar demographic and preoperative physiologic parameters. Group A (n = 16) was submitted to thoracoscopic, internal intercostal nerve blocks performed at T2, T3, and T4 intercostal levels using 3 cc of 0.5% bupivacain in each intercostal space. The injections were performed bilaterally, immediately after the sympathectomy, through the same port. Group B (n = 16) underwent bilateral thoracic sympathectomy without the block. During the immediate postoperative period, heart rate, blood pressure, respiratory rate, pain score, and analgesic requirements were monitored every 30 minutes.

Results. No morbidity was recorded in association with the thoracoscopic, internal intercostal nerve block. The mean heart rates (77 ± 6 vs 89 ± 12 beats per minute, p < 0.001), respiratory rates (15 ± 2 vs 18 ± 3 respirations per minute, p < 0.01), pain score (1.9 ± 0.6 vs 2.7 ± 0.5, p < 0.01), and postoperative analgesic requirements (20 ± 18 vs 50 ± 21 mg pethidine HCL, p < 0.001) were significantly lower in group A. There was no significant difference in blood pressures.

Conclusions. Thoracoscopic, internal intercostal nerve block with bupivacain 0.5% during VATS is safe and effectively reduced the immediate postoperative pain and analgesic requirements.     

Genetic background influences fluoride's effects on osteoclastogenesis

Excessive fluoride (F) can lead to abnormal bone biology. Numerous studies have focused on the anabolic action of F yet little is known regarding any action on osteoclastogenesis. Little is known regarding the influence of an individual's genetic background on the responses of bone cells to F. Four-week old C57BL/6J (B6) and C3H/HeJ (C3H) female mice were treated with NaF in the drinking water (0 ppm, 50 ppm and 100 ppm F ion) for 3 weeks. Bone marrow cells were harvested for osteoclastogenesis and hematopoietic colony-forming cell assays. Sera were analyzed for biochemical and bone markers. Femurs, tibiae, and lumbar vertebrae were subjected to microCT analysis. Tibiae and femurs were subjected to histology and biomechanical testing, respectively. The results demonstrated new actions of F on osteoclastogenesis and hematopoietic cell differentiation. Strain-specific responses were observed. The anabolic action of F was favored in B6 mice exhibiting dose-dependent increases in serum ALP activity (p < 0.001); in proximal tibia trabecular and vertebral BMD (tibia at 50&100 ppm, p = 0.001; vertebrae at 50 and 100 ppm, p = 0.023&0.019, respectively); and decrease in intact PTH and sRANKL (p = 0.045 and p < 0.001, respectively). F treatment in B6 mice also resulted in increased numbers of CFU-GEMM colonies (p = 0.025). Strain-specific accumulations in bone [F] were observed. For C3H mice, dose-dependent increases were observed in osteoclast potential (p < 0.001), in situ trabecular osteoclast number (p = 0.007), hematopoietic colony forming units (CFU-GEMM: p < 0.001, CFU-GM: p = 0.006, CFU-M: p < 0.001), and serum markers for osteoclastogenesis (intact PTH: p = 0.004, RANKL: p = 0.022, TRAP5b: p < 0.001). A concordant decrease in serum OPG (p = 0.005) was also observed. Fluoride treatment had no significant effects on bone morphology, BMD, and serum PYD cross-links in C3H suggesting a lack of significant bone resorption. Mechanical properties were also unaltered in C3H. In conclusion, short term F treatment at physiological levels has strain-specific effects in mice. The expected anabolic effects were observed in B6 and novel actions hallmarked by enhanced osteoclastogenesis shifts in hematopoietic cell differentiation in the C3H strain.     

Antiinflammatory effects of colforsin daropate hydrochloride, a novel water-soluble forskolin derivative

Background. To evaluate the effects of colforsin daropate hydrochloride (colforsin), a water-soluble forskolin derivative, on hemodynamics and systemic inflammatory response after cardiopulmonary bypass, we conducted a prospective randomized study.

Methods. Twenty-nine patients undergoing coronary artery bypass grafting were randomized to receive either colforsin treatment (colforsin; N = 14) or no colforsin treatment (control; N = 15). Administration of colforsin (0.5 μg · kg⁻¹ · min⁻¹) was started after induction of anesthesia and was continued for 6 hours. Perioperative cytokine and cyclic adenosine monophosphate levels, hemodynamics, and respiratory function were measured serially.

Results. Marked positive inotropic and vasodilatory effects were observed in patients receiving colforsin. Interleukin 1β, interleukin 6, and interleukin 8 levels after cardiopulmonary bypass were significantly (p < 0.05) lower in the colforsin group. Plasma levels of cyclic adenosine monophosphate increased significantly (p < 0.05) in the colforsin group, and the levels correlated inversely (r = −0.56, p = 0.002) with the respiratory index after cardiopulmonary bypass.

Conclusions. Intraoperative administration of colforsin daropate hydrochloride had potent inotropic and vasodilatory activity and attenuated cytokine production and respiratory dysfunction after cardiopulmonary bypass. The results indicate that the technique can be a novel therapeutic strategy for the systemic inflammatory response associated with cardiopulmonary bypass.