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Tatu Juvonen

Publications and source records attributed to Tatu Juvonen.

52 records · Page 3Linked to original sources
PubMed2003

Does angiographic severity of coronary artery disease predict postoperative outcome after coronary artery bypass surgery?

OBJECTIVE: It is not clear whether the severity of coronary artery disease as assessed on angiography has an impact on the postoperative outcome after coronary artery bypass surgery (CABG). DESIGN: The angiographic status of 15 coronary arteries/segments of 2,233 patients who underwent isolated on-pump CABG was graded according to the following criteria: 1 = no stenosis; 2 = stenosis <50%; 3 = stenosis of 50-69%; 4 = stenosis of 70-89%; 5 = stenosis of 90-99%; 6 = vessel occlusion; and 7 = vessel is not visualized. RESULTS: Thirty-seven patients (1.7%) died during the in-hospital stay and 108 (4.8%) developed postoperatively low cardiac output syndrome. Multivariate analysis showed that along with other risk factors the overall coronary angiographic score was predictive of postoperative death (p = 0.03; OR: 1.027, 95% CI: 1.003-1.052) and of low cardiac output syndrome (p = 0.04; OR: 1.172, 95% CI: 1.010-1.218). The status of the proximal segment of the left circumflex coronary artery, the diagonal arteries and the left obtuse marginal arteries was most closely associated with adverse postoperative outcome. CONCLUSION: The angiographic status of coronary arteries has an impact on the immediate outcome after CABG.

Aged↗
PubMed2002

Ten-year outcome of patients with very small abdominal aortic aneurysm.

BACKGROUND: The long-term fate of very small abdominal aortic aneurysms (AAA) is not well known. METHODS: Forty-one patients with asymptomatic small AAA (range 25 to 40 mm) underwent ultrasonographic surveillance. RESULTS: The median follow-up period was 7.3 years. The median linear aneurysm expansion rate was 2.0 mm/year (range 0 to 8.4). Three patients experienced aneurysm rupture (7.3%) which resulted in 1 patient'death. Thirteen patients underwent aneurysm repair (31.7%) and 1 patient died postoperatively (7.7%). The survival rate at 10-year follow-up was 59.0%. The survival rate free from aneurysm rupture and repair at 10-year follow-up was 69.9%. The median time for occurrence of aneurysm rupture was 4.9 years (range 1.8 to 10.5) and the need for aneurysm repair was 4.5 years (range 1.4 to 10.4). CONCLUSIONS: The fate of very small AAA is to slowly enlarge in size, sometimes threatening the patient's life. These observations underline the importance of continuous surveillance and the potential benefits of any medical treatment in this patient population.

Adult↗
PubMed2002

Lamotrigine plus leukocyte filtration as a neuroprotective strategy in experimental hypothermic circulatory arrest.

BACKGROUND: Lamotrigine and leukocyte filtration seem to improve cerebral protection during experimental hypothermic circulatory arrest (HCA). This study was performed to evaluate whether their combined use may further improve cerebral protection. METHODS: Twenty-four pigs undergoing 75-minute period of HCA at 20 degrees C were randomly assigned to receive saline; lamotrigine (20 mg/kg) before HCA (L); or lamotrigine (20 mg/kg) before HCA plus leukocyte filtration before and after HCA (L + LF). RESULTS: Seven animals (87%) in the L + LF group, 4 (50%) in the L group, and 3 (37%) in the control group were alive on the seventh postoperative day. The median electroencephalogram burst recovery was 94% in the L + LF group (p = 0.024 versus control group), 81% in the L group, and 64% in the control group. Among the surviving animals, the median behavioral scores were 9, 9, and 6 at the seventh day, respectively (p = 0.005 between the L + LF group and the control group). The median histopathologic score was 14 in the L + LF group (p = 0.046 versus control group), 14.5 in the L group (p = 0.062 versus control group), and 21 in the control group. CONCLUSIONS: Lamotrigine has neuroprotective effect during HCA. The combined use of lamotrigine and LF may further improve the survival outcome.

Animals↗
PubMed2002

Effect of hypothermia on cerebral blood flow and metabolism in the pig.

BACKGROUND: The pig has become an increasingly popular model for the study of cerebral protection during cardiothoracic surgery in recent years, but little information is available concerning hypothermic porcine physiology. Because the efficacy of cerebral protection depends largely upon metabolic suppression, we studied cerebral oxygen metabolism at various temperatures using two different methods to assess cerebral blood flow (CBF). MATERIAL AND METHODS: Twelve pigs (7 to 13 kg) underwent cooling on cardiopulmonary bypass to 8 degrees C as recorded by an electrode placed deep in the parenchyma of the brain. CBF was measured in 6 animals using radioactive microspheres and in the other 6 using fluorescent microspheres. CBF, cerebral oxygen consumption, and cerebral vascular resistance were determined at 37 degrees C, 28 degrees C, 18 degrees C, and 8 degrees C. RESULTS: Both methods produced very similar data. CBF fell steadily with decrease in temperature to 18 degrees C but failed to drop further with more profound hypothermia. With both groups combined, mean cerebral oxygen metabolism was 2.63 mL/100 g per minute at 37 degrees C. Metabolic activity was 50% of base line values at 28 degrees C, 19% at 18 degrees C, and 11% at 8 degrees C. The Q10 value in the pig--the degree of metabolic suppression achieved by a 10 degrees C drop in temperature--is 2.46 (95% confidence interval 2.1 to 2.9); this value is consistent with similar studies in humans. CONCLUSIONS: The presence of significant residual metabolic activity at 18 degrees C suggests that this degree of hypothermia may provide incomplete cerebral protection during prolonged interruption of CBF. This study demonstrates that cooling to temperatures below 18 degrees C in the pig can achieve greater metabolic suppression although it may be associated with loss of cerebral autoregulation.

Animals↗
PubMed2002

Automatic analysis and monitoring of burst suppression in anesthesia.

OBJECTIVE: We studied the spectral characteristics of the EEG burst suppression patterns (BSP) of two intravenous anesthetics, propofol and thiopental. Based on the obtained results, we developed a method for automatic segmentation, classification and compact presentation of burst suppression patterns. METHODS: The spectral analysis was performed with the short time Fourier transform and with autoregressive modeling to provide information of frequency contents of bursts. This information was used when designing appropriate filters for segmentation algorithms. The adaptive segmentation was carried out using two different nonparametric methods. The first one was based on the absolute values of amplitudes and is referred to as the ADIF method. The second method used the absolute values of the Nonlinear Energy Operator (NLEO) and is referred to as the NLEO method. Both methods have been described earlier but they were modified for the purposes of BSP detection. The signal was classified to bursts, suppressions and artifacts. Automatic classification was compared with manual classification. Results. The NLEO method was more accurate, especially in the detection of artifacts. NLEO method classified correctly 94.0% of the propofol data and 92.8% of the thiopental data. With the ADIF method, the results were 90.5% and 88.1% respectively. CONCLUSIONS: Our results show that burst suppression caused by the different anesthetics can be reliably detected with our segmentation and classification methods. The analysis of normal and pathological EEG, however, should include information of the anesthetic used. Knowledge of the normal variation of the EEG is necessary in order to detect the abnormal BSP of, for instance, seizure patients.

Adult↗
PubMed2002

Prolonged mild hypothermia after experimental hypothermic circulatory arrest in a chronic porcine model.

OBJECTIVES: We sought to evaluate the potential efficacy of prolonged mild hypothermia after hypothermic circulatory arrest. METHODS: Twenty pigs, after a 75-minute period of hypothermic circulatory arrest, were randomly assigned to be rewarmed to 37 degrees C (normothermia group) or to 32 degrees C and kept at that temperature for 14 hours from the start of rewarming (hypothermia group). RESULTS: The 7-day survival was 30% in the hypothermia group and 70% in the normothermia group (P =.08). The hypothermia group had poorer postoperative behavioral scores than the normothermia group. Prolonged hypothermia was associated with lower oxygen extraction and consumption rates and higher mixed venous oxygen saturation levels during the first hours after hypothermic circulatory arrest. Decreased cardiac index, lower pH, and higher partial pressure of carbon dioxide were observed in the hypothermia group. There was a trend for beneficial effect of prolonged hypothermia in terms of lower brain lactate levels until the 4-hour interval and of intracranial pressure until the 10-hour interval. Postoperatively, total leukocyte and neutrophil counts were lower, and creatine kinase BB was significantly increased in the hypothermia group. At extubation, the hypothermia group had higher oxygen extraction rates and lower brain tissue oxygen tension. CONCLUSIONS: A 14-hour period of mild hypothermia after 75-minute hypothermic circulatory arrest seems to be associated with poor outcome. However, the results of this study suggest that mild hypothermia may preserve its efficacy when it is used for no longer than 4 hours, but the potentials of a shorter period of postoperative mild hypothermia still require further investigation.

Animals↗
PubMed2002

Potential neuroprotective benefits of erythropoietin during experimental hypothermic circulatory arrest.

OBJECTIVE: Recent studies have shown that erythropoietin protects neurons from glutamate toxicity and ischemia. This study was performed to evaluate the potential neuroprotective effect of erythropoietin during experimental hypothermic circulatory arrest. METHODS: Twenty pigs were randomized to receive intravenously either 500 IU/kg recombinant human erythropoietin or saline before a 75-minute period of hypothermic circulatory arrest at an intracerebral temperature of 18 degrees C. RESULTS: After the administration of erythropoietin, its concentration in the cerebrospinal fluid increased 4.5-fold 8 hours after the start of rewarming, whereas it did not increase in control animals. The 7-day survival rate was 60% in the erythropoietin group and 70% in the control group (P = 1.0). No significant differences were observed between the study groups in terms of electroencephalography, behavioral score, and histopathologic score. The erythropoietin group had higher vascular resistance and mean arterial pressure values, lower intracerebral concentrations of glutamate and glycerol, higher brain tissue oxygen tension, and lower apoptotic index. CONCLUSIONS: Administration of 500 IU/kg erythropoietin intravenously before hypothermic circulatory arrest was followed by an increased erythropoietin concentration in the cerebrospinal fluid. Although previous studies have demonstrated neuroprotective effects of erythropoietin during brain ischemia, the present study, using a chronic porcine model, failed to show any significant benefit after administration of erythropoietin in terms of mortality or brain histopathology. Lower intracerebral concentrations of glutamate and glycerol, higher brain tissue oxygen tension, and lower apoptotic index observed in the erythropoietin group, however, suggest that a distinct neuroprotective effect of erythropoietin might be achieved at different dosages and timing of administration.

Animals↗
PubMed2002

Durability of open repair of infrarenal abdominal aortic aneurysm: a 15-year follow-up study.

PURPOSE: This study reviewed the long-term outcome of patients who underwent open repair of infrarenal abdominal aortic aneurysms (AAAs). METHODS: A retrospective study of 208 patients (188 men and 20 women) with a mean age of 65.6 years who survived elective or emergency open repair of an infrarenal AAA was conducted at a university referral hospital. Main outcome measures included late graft-related complications, survival free from any reintervention, survival free from any vascular reintervention, and overall survival rates. RESULTS: Late graft-related complications occurred in 32 patients (15.4%). A proximal para-anastomotic pseudoaneurysm developed in six patients (2.9%), and a distal pseudoaneurysm developed in 18 patients (8.7%); in seven of these cases (3.4%), it was bilateral or recurrent. A graft limb occlusion occurred in 11 patients (5.3%). These complications required 37 surgical or other invasive procedures in 27 patients (13.0%). Thirty-one vascular and/or endovascular reoperations were performed. The 5-year, 10-year, and 15-year survival free from any reintervention rates were 91.5%, 86.2%, and 72.0%, respectively. At the same intervals, the survival free from any vascular reintervention rates were 93.8%, 88.5%, and 73.9%, respectively, and the overall survival rates were 66.8%, 39.4%, and 18.0%, respectively. Complications associated with a ruptured femoral artery pseudoaneurysm, a ruptured aortic pseudoaneurysm, an aortoduodenal fistula, and the elective repair of a femoral pseudoaneurysm were the graft-related causes of death, which occurred in four patients (1.9%). Age (P <.0001) and chronic obstructive pulmonary disease (P =.002) were shown by means of multivariate analysis to be predictive of poor survival outcome, and chronic obstructive pulmonary disease (P =.02) and lower limb ischemia (P =.04) were shown to be associated with an increased need for vascular reinterventions to treat graft-related complications. CONCLUSION: Open repair of infrarenal AAAs can achieve satisfactory 15-year follow-up rates of survival free from reintervention for any graft-related complications, suggesting that surgery should still be considered the procedure of choice for infrarenal AAAs, at least in patients who are fit for surgery.

Adult↗
PubMed2002

Endovenous obliteration versus conventional stripping operation in the treatment of primary varicose veins: a randomized controlled trial with comparison of the costs.

OBJECTIVE: The aim of this randomized study was to compare a new method of endovenous saphenous vein obliteration (Closure System, VNUS Medical Technologies, Inc, Sunnyvale, Calif) with the conventional stripping operation in terms of short-term recovery and costs. METHODS: Twenty-eight selected patients for operative treatment of primary greater saphenous vein tributary varicose veins were randomly assigned to endovenous obliteration (n = 15) or stripping operation (n = 13). Postoperative pain was daily assessed during the 1st week and on the 14th postoperative day. The length of sick leave was determined. The RAND-36 health survey was used to assess the patient health-related quality of life. The patient conditions were controlled 7 to 8 weeks after surgery, and patients underwent examination with duplex ultrasonography. The comparison of costs included both direct medical costs and costs resulting from lost of productivity of the patients. Costs that were similar in the study groups were not considered in the analysis. RESULTS: All operations were successful, and the complication rates were similar in the two groups. Postoperative average pain was significantly less severe in the endovenous obliteration group as compared with the stripping group (at rest: 0.7, standard deviation [SD] 0.5, versus 1.7, SD 1.3, P =.017; on standing: 1.3, SD 0.7, versus 2.6, SD 1.9, P =.026; on walking: 1.8, SD 0.8, versus 3.0, SD 1.8, P =.036; with t test). The sick leaves were significantly shorter in the endovenous obliteration group (6.5 days, SD 3.3 days, versus 15.6 days, SD 6.0 days; 95% CI, 5.4 to 12.9; P <.001, with t test). Physical function was also restored faster in the endovenous obliteration group. The estimated annual investment costs of the closure operation were US $3360. The other direct medical costs of the Closure operation were about $850, and those of the conventional treatment were $360. With inclusion of the value of the lost working days, the Closure treatment was cost-saving for society, and when 40% of the patients are retired (or 60% of the productivity loss was included), the Closure procedure became cost-saving at a level of 43 operations per year. CONCLUSION: Endovenous obliteration may offer advantages over the conventional stripping operation in terms of reduced postoperative pain, shorter sick leaves, and faster return to normal activities, and it appears to be cost-saving for society, especially among employed patients. Because the procedure is also associated with shorter convalescence, this new method may potentially replace conventional varicose vein surgery.

Adult↗
PubMed2002

A retrospective comparative study of aortic valve replacement with St. Jude medical and medtronic-hall prostheses: a 20-year follow-up study.

OBJECTIVE: To compare the long-term clinical outcome of patients who underwent aortic valve replacement with St. Jude Medical and Medtronic-Hall mechanical prostheses. DESIGN: From June 1978 to June 1982, 43 Medtronic-Hall and 48 St. Jude Medical mechanical valves were implanted in 90 consecutive patients with aortic valve disease, and their clinical outcome was retrospectively assessed. RESULTS: At 20 years in the St. Jude Medical group and in the Medtronic-Hall group the actuarial rates of overall survival were 50 and 49% (p = NS), of cardiovascular survival 66 and 63% (p = NS), of valve-related survival 95 and 91% (p = NS), of freedom from major valve-related complications 83 and 45% (p = 0.005), from major cerebrovascular events 93 and 71% (p =0.06), from valve thrombosis 97 and 89% (p = NS), from aortic valve reoperation 93 and 88% (p = NS), from major bleeding 96 and 82% (p = 0.04), and from endocarditis 93 and 82% (p = NS), respectively. The linearized rate of overall major aortic valve prosthesis-related complications was 3.47%/year in the Medtronic-Hall valve group and 1.53%/year in the St. Jude Medical valve group (p = 0.003). Multivariate analysis showed that the type of prosthesis was predictive of freedom from valve-related complications (p = 0.01; 2.849; C.I. 95%: 1.246-6.516). CONCLUSION: The aortic St. Jude Medical mechanical valve seems to be associated with a slightly lower rate of long-term valve-related morbidity than the aortic Medtronic-Hall mechanical valve. Because of the small patient population and the retrospective nature of the study, the choice between these two prostheses should not be made only on the basis of these findings. However, these results suggest a reappraisal for further comparative studies with such an extended follow-up.

Adult↗
PubMed2002

Increase of intracranial pressure after hypothermic circulatory arrest in a chronic porcine model.

OBJECTIVE: An increase in intracranial pressure has been shown to threaten the outcome of patients with ischemic or traumatic brain injury. Its impact on the outcome of pigs undergoing hypothermic circulatory arrest has been evaluated in this study. DESIGN: Fifty-six pigs underwent a 75-min period of hypothermic circulatory arrest at 20 degrees C. Intracranial pressure, cerebral microdialysis, hemodynamic and metabolic parameters were monitored throughout the experiment. The animals were allowed to survive until the 7th postoperative day and, then, electively killed. RESULTS: The 7-day survival rate was 60.7%, and among survivors, 20 of them (58.8%) developed brain infarction. A significant increase in intracranial pressure as compared with the baseline level was observed since the end of cooling (p = 0.047) and the difference became larger during all the postoperative intervals (p < 0.0001). Animals that died postoperatively tended to have higher intracranial pressure levels during all the postoperative intervals, but such a difference reached significance only at the 4-h postoperative interval (p = 0.040). The same tendency was observed among animals that survived until the 7th postoperative day and that developed brain infarction or not, but the difference between these two groups did not reach statistical significance. The animals that died or developed postoperatively brain infarction had higher intracranial pressure values postoperatively as compared with those that survived without developing brain infarction and such a difference reached significance at the 2-h (p = 0.015) and 4-h postoperative intervals (p = 0.035). The peak intracranial pressure was 17.2 mmHg (IQR, 13.7-20.8) in animals that died or developed brain infarction and 14.1 mmHg (IQR, 11.8-16.4) in those that survived 7 days without developing brain infarction (p = NS). CONCLUSION: Intracranial pressure increases significantly after 75 min of experimental hypothermic circulatory arrest and such an increase is associated with a high risk of postoperative death and brain infarction.

Animals↗