Morphologic alterations of myocardium under conditions of left ventricular assistance.
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Adult↗
Biomedical subjects
R Dion
Publications and source records attributed to R Dion.
Long-term survival after aortic valve replacement for native active infective endocarditis.
BACKGROUND: The objective of this study was to analyse the impact of acute surgery for native aortic valve endocarditis and its influence on the long-term prognosis after surgery. METHODS: A total of 161 patients underwent aortic valve replacement for native active aortic valve endocarditis (NAAVE) during a 29-year period, from 1967 to 1995 (age range: 10 to 72 years; mean 48 +/- 12). The main indication for surgery was progressive congestive heart failure (76%). Other indications were untreatable sepsis (27%), peripheral or central emboli (12%) and, from 1978, echocardiographic evidence of friable, pedunculated vegetations (3%). Streptococcal and staphylococcal infections predominated. Concomitant procedures were performed in 27% of the patients, including mitral and tricuspid valve surgery and coronary bypass procedures. RESULTS: Operative mortality was 8% in the majority of cases caused by heart failure or multi-organ failure. Multivariate logistic regression analysis identified NYHA class IV to be an independent predictor for postoperative death. Long-term survival for discharged patients was 75% at 10 years and 58% at 15 years, with a mortality rate of 3.6%/patient/year. Cox regression analysis identified the year of operation, trivalvular endocarditis and staphylococcal infection as independent predictors of survival. At 10 and 15 years after aortic valve replacement, 91% and 84% of the patients, respectively, were free of recurrent endocarditis. The presence of an abscess cavity at first operation was found to be predictive of recurrent endocarditis. CONCLUSIONS: Valve replacement for NAAVE offers a good chance for a cure and satisfactory long-term survival. Improvements in pre- and per-operative management of the very ill patient, and the use of allograft valves are likely to further improve long-term results. Finally, the presence of staphylococcal endocarditis requires long-term postoperative antibiotic therapy.
Adolescent↗
Use of the right gastroepiploic artery as a coronary artery bypass graft in 307 patients.
From October 1988 to October 1995 the right gastroepiploic artery was used as a conduit for coronary surgery in 307 patients. Their average age was 56.5 years (range 25-75) and 274 patients (89%) were male. Twenty-six cases (8.5%) were re-operations and 58 patients (19%) were operated upon on an urgent or semi-urgent basis. Target coronary vessels were the right coronary artery and its branches in 280 cases (91.4%), the circumflex artery in 25 cases (8%) and the left anterior descending artery in two cases. The right gastroepiploic artery was used as an in situ graft in 303 cases (98.7%) and as a free graft in 4 (1.3%). A total of 291 patients (94.8%) also received at least one mammary artery graft: both mammary arteries were used in 167 patients (54.4%). An average of 3.6 distal anastomoses were made per patient, three of them with arterial grafts. Eleven (3.2%) right gastroepiploic artery grafts were doubled with saphenous vein intraoperatively because of persistent myocardial ischemia. In-hospital mortality was 1.6% (five patients). Perioperative myocardial infarction occurred in twelve patients (3.9%). Follow-up now averages 26 months (range 6-88). There have been five late deaths (1.6%). A total of 265 (89.2%) patients are angina free. Of the total, 145 patients have been investigated with a maximal-stress test coupled with scintigraphy: residual myocardial ischemia was found in 10 patients, right gastroepiploic artery was related in three. Ninety-six patients have undergone angiographic restudy at a mean of 12 months (range 8-88) postoperatively. Patency of the right gastroepiploic artery grafts was 91.8%. This study confirms that the right gastroepiploic artery can be used as a conduit for coronary artery bypass surgery with minimal mortality or morbidity. Mid-term patency rates and clinical outcome are encouraging.
Adult↗
Radical debridement and omental transposition for post sternotomy mediastinitis.
OBJECTIVE: Reported mortality for postoperative mediastinitis treated by debridement alone can reach 40%. The authors' experience with radical debridement and omental transposition is reviewed. METHODS: Between May 1990 and August 1996, 14 patients with untractable mediastinitis had a transfer of the greater omentum: 11 after coronary artery bypass grafting (CABG) (6 bilateral internal thoracic arteries ITA grafts), one after a heart transplant, one after an aortic valve replacement and CABG, and one after a repair of the aortic isthmus related to a motor vehicle accident. The mean age was 63 +/- 8 years. Infection was proven in all patients by cultures of intraoperative specimens. Two patients had such a large sternal defect that no primary closure could be attempted. The remaining 12 patients had a mean of 1.4 +/- 0.7 previous debridement. Five patients had a total sternectomy. After radical debridement, the omentum was transferred over the entirety of the wound and covered with a meshed thin skin graft. All patients had a minimum of 4 weeks of i.v. antibiotic therapy. RESULTS: There was no operative death. Apart from one focal necrosis and one traumatic dehiscence of the omentum, there was no hospital complication. Sepsis was controlled in all patients. The median hospital stay was 31 days (range 20-154 days). At a median follow-up of 20 months (range: 6-44 months), there were two late deaths: one sudden and unexpected death and one after a re-do CABG. The remaining patients had resumed their previous activities. One patient had developed an incisional hernia and another underwent further surgery for cosmetic reasons. CONCLUSION: Radical debridement and omental transposition may achieve a cure for postoperative mediastinitis with good mid-term results.
Aged↗
[Sensitivity, specificity, and impact on the surgical strategy of the perioperative neuromonitoring of somatic evoked potentials in vascular surgery performed with circulatory arrest under deep hypothermia].
AIM: Median nerve somatosensory evoked potentials (SEP) monitoring performed in deep hypothermic circulatory arrest is useful in determining when brain cooling may sufficiently permit circulatory arrest, and to immediately indicate when brain injury occurs. The aim of this retrospective study, including 58 patients, is to determine SEP sensitivity, specificity and impact on the surgical strategy. METHOD: Sensitivity was determined on patients presenting new neurological complications. Specificity was measured on the patients without any new neurological defect. The impact of intraoperative SEP on the surgical strategy was determined when the occurrence of SEP alterations had provoked a modification of the surgical procedure. RESULTS: Five patients died intraoperatively due to non-neurological complications. Fourteen patients presented new neurological complications. SEP sensitivity reaches 64.3% when all the complications are included, but increases to 100% in our series if late postoperative complications, paraplegia and tibial posterior nerve lesion are excluded because median nerve SEP are not able to detect such complications. SEP monitoring was uneventful in the 39 patients whose did not present neurological complication: thus SEP specificity is absolute in our series. SEP had an impact on the surgical procedure whenever neurological complications due to hemodynamic disturbances occurred. CONCLUSION: This retrospective study shows the interest of intraoperative SEP as an useful tool for promptly identifying and preventing the neurological complication of hypothermic circulatory arrest.
Adolescent↗
Cardiac troponin I as an early marker of myocardial damage after coronary bypass surgery.
STUDY OBJECTIVE: To evaluate the performance of cardiac specific markers, cardiac troponin I (cTnI) and CK-MB by mass assay (CK-MB mass), for the early diagnosis of myocardial ischemia and/or infarction after coronary bypass surgery. METHODS: Prospective clinical, electrocardiograpic and biologic follow-up of 117 patients undergoing isolated coronary surgery with the use of intermittent anterograde normothermic blood cardioplegia. Blood samples for biochemical analysis were drawn before surgery (T0) and at 2 (T1), 6 (T2), 10 (T3) and 20 h (T4) after aortic cross-clamp release. Without knowledge of the biochemical data, patients were classified according to the electrocardiographic evolution into two groups: group 1, uneventful recovery and group 2, evidence of ischemia/infarction based on continuous ST-T segment monitoring and 12-lead ECG. RESULTS: No patients had abnormal markers at T0. At T1, although both markers were elevated, no difference was noted between the two groups. At T2, 6 h after surgery, cTnI and CK-MB mass levels were significantly higher in group 2 than in group 1 (median = 17 microg/l, Interquartile Range (IR): 14.7-27.3 vs. 3.1 microg/l, IR 1.9-5.3 for cTnI and median 42.5 microg/l, IR: 27.1-95.7 vs. 13.6 microg/l, IR: 9.5-18.5 for CK-MB mass). A receiver operating characteristic (ROC) curve analysis shows that a cTnI value of 13.1 microg/ml has 100% specificity and 90% sensitivity to separate both groups, whereas a value of 33.2 microg/ml for CK-MB mass has a specificity of 100% and a sensitivity of 73%. At T3 and T4, the same difference was noted between the groups. cTnI values in all six patients with a Q-wave infarction were > or = 20 ng/ml, whereas only one of five patients with prolonged ischemia had cTnI level > 20 ng/ml. CONCLUSION: As soon as 6 h postoperatively, cTnI and CK-MB by mass assay were able to separate those patients with an uneventful recovery from those with significant ischemia. This is particularly useful in frequent cases when the ECG is difficult to interpret.
Biomarkers↗
Mental health and the academic performance of first nations and majority-culture children.
Prior classroom achievement and verbal IQ are identified as predictors of school performance for both Native and non-Native youngsters. Children's assessments of their competence, which appear to be, in part, a product of interactions with teachers, were found to be independent predictors of classroom performance. Results suggest that verbal IQ and compromised self-assessments contribute to the difficulties many Native children experience in majority-culture schools.
Acculturation↗
Chronic dissection of the thoracic aorta in a patient with tuberculous pleuro-pericarditis.
We describe a case of chronic dissection of thoracic aorta presumed to be due to tuberculosis from pleuro-pericarditis foci and who was cured by antituberculous therapy and surgery. With the recent increase of tuberculosis cases, tuberculous aortitis might become less rare and the clinicians should suspect this diagnosis in subjects with aortic dissection and history of tuberculosis.
Adult↗
Depression and conduct disorder in native and non-native children.
OBJECTIVE: To compare depression and conduct disorder symptoms between North American Native and non-Native children as rated by teacher, parent, and self-reports. METHOD: The sample included 1,251 Native children in grades 2 and 4 in four different settings across North America and comparison samples of 457 non-Native children. Parents, teachers, and children rated children's mental health using culturally sensitive measures of depression and conduct disorder symptoms. RESULTS: According to parent ratings and child self-reports, there were no Native/non-Native differences in levels of conduct disorder symptoms. However, non-Native teachers rated higher levels of conduct disorder symptoms among Native children compared with non-Native students. Children reported higher levels of depression than the adults rating them. CONCLUSIONS: Results challenge assertions about high levels of psychopathology among Native youngsters. Cultural distance may introduce a negative bias in teacher evaluations of Native children's mental health.
Child↗
Validation of cardiac echocardiography for measuring cardiac output to be applied for the multiple inert gas elimination technique.
The multiple inert gas elimination technique (MIGET) is being increasingly used in respiratory physiology and pathophysiology. Six inert gases are given as an intravenous infusion then measured in samples of expired air and mixed arterial and venous blood. This requires right-sided catheterization, a procedure that is sometimes ethically inappropriate. The present article reports a method in which inert gas levels in mixed venous blood were calculated, rather than measured, using Fick's law. Echocardiography was used to measure arterial inert gas levels and cardiac output. The method was validated in 11 men scheduled to undergo coronary bypass surgery. Cardiac output was either calculated based on biometrical (C) data or measured using four different methods in random order, namely Fick's law with oxygen (FiO2) or the inert gases (FiIG) as the tracers, thermodilution (TH), and echocardiography (E). Cardiac output values in L.min-1 (mean +/- SD) were as follows: C, 4.99 +/- 0.39; FiO2, 5.44 +/- 0.86; FiIG, 5.55 +/- 0.92; TH, 5.77 +/- 0.88; and E, 5.53 +/- 0.64. No significant differences were found among the four measured cardiac output values, of which the mean was 5.57 +/- 0.70 L/min, a value that was significantly higher than the calculated value. This difference is probably ascribable to the use of dopamine, dobutamine, or epinephrine in six of the 11 patients. A 1 L/min-1 cardiac output error, in either direction, was found to have a marked influence on the distribution of alveolar perfusion at various VA/Q ratios. Conversely, as expected, ventilation distribution was not influenced by cardiac output. In conclusion, echocardiography provides satisfactory cardiac output estimations using the MIGET except in patients with septal hypertrophy, subaortic membranes, a mitral valve prosthesis, or a mitral valve ring.
Adult↗
Popliteal-to-distal bypass grafts for limb salvage.
From July 1989 to July 1994, a total of 44 popliteal-to-distal artery bypasses were performed in 36 patients (29 men and seven women, mean age 62 +/- 10 years). These procedures accounted for 8.8% of all infrainguinal revascularizations performed during that period. Risk factors included diabetes in 33 patients (92%), smoking in 18 (50%), and coronary artery disease in 15 (42%). Prior to revascularization all patients were at risk of limb loss. Tissue necrosis was present in 31 cases (71%), ulceration in eight cases (18%), and rest pain in five cases (11%). Patency of the femoral and popliteal arteries was confirmed prior to surgery in all cases. Intraoperative percutaneous angioplasty of the superficial femoral artery was performed in three cases. Proximal anastomosis was made to the distal popliteal artery in all cases. A total of 52 distal anastomoses (eight sequential bypasses) were made on the following arteries: posterior tibial artery in 13 cases, anterior tibial artery in eight cases, peroneal artery in six cases, plantar artery in two cases, and dorsalis pedis artery in 21 cases. The greater saphenous vein was used as graft material in 42 cases (95%) and the lesser saphenous vein in two cases (5%). No patient died during hospitalization. Early bypass occlusion occurred in three cases (6.8%) and led to amputation in all cases. Secondary patency and limb salvage rates at 3 years calculated using the actuarial method were 74% and 82% respectively. Bypass thrombosis due to superficial femoral artery deterioration was not observed in any case. The present study indicates that popliteal-to-distal artery bypass is a simple, durable, and low-risk method of lower limb revascularization. Medium-term results are promising and support routine use of popliteal-to-distal artery bypass for limb salvage in patients without significant stenosis of the superficial femoral artery.
Aged↗
Correlation of functional recovery with myocardial blood flow, glucose uptake, and morphologic features in patients with chronic left ventricular ischemic dysfunction undergoing coronary artery bypass grafting.
OBJECTIVE: Our objective was to investigate the influence of preoperative myocardial ultrastructure and metabolism on recovery of contractile function after coronary artery bypass grafting in patients with coronary artery disease and left ventricular dysfunction. METHODS: Dynamic positron emission tomography with 13N-ammonia and 18F-deoxyglucose was used to assess myocardial perfusion and glucose uptake in 53 patients scheduled for coronary revascularization because of coronary artery disease and left ventricular dysfunction. The degree of tissue fibrosis and the presence of potentially reversible alterations of cardiomyocytes (loss of myofilaments and accumulation of glycogen) were quantified from transmural biopsy specimens. These were harvested from the center of the dysfunctional area during the operation and analyzed with a light microscope. The recovery of contractile performance was assessed from the changes in left ventricular function at contrast ventriculography or echocardiography before and 6 months after the operation. RESULTS: According to postoperative changes in regional wall motion, left ventricular function was considered to have improved in 34 patients, whereas dysfunction persisted in 19 patients. In patients with improved wall motion, ejection fraction rose by 12% and end-systolic volume decreased by 28%. By contrast, in patients with persistent dysfunction, ejection fraction decreased by 6% and end-systolic volume increased by 25%. Before revascularization, myocardium with reversible dysfunction displayed higher levels of absolute myocardial blood flow, higher myocardial glucose uptake, less tissue fibrosis, and more altered cardiomyocytes than myocardium with persistent dysfunction. Significant correlations were found between regional blood flow and the surface of the biopsy specimen covered by fibrosis, as well as between glucose uptake and the density of altered cardiomyocytes. CONCLUSION: In patients with left ventricular ischemic dysfunction, the recovery of regional and global left ventricular function after surgical revascularization is associated with higher preoperative blood flow and glucose uptake, with less tissue fibrosis and a higher amount of viable cardiomyocytes in the dysfunctional area. The current study thus confirms the value of noninvasive preoperative metabolic imaging for identification of residual viable myocardium and for prediction of the functional outcome after revascularization.
Adult↗
Somatosensory evoked potential monitoring in carotid surgery. I. Relationships between qualitative SEP alterations and intraoperative events.
This paper presents the results of intraoperative median nerve SEP monitoring in 205 successive patients undergoing isolated carotid endarterectomy (CE) (N = 172) or CE followed by coronary bypass (CBP) and/or vascular replacement (VR) (N = 33). The left and right median nerves were alternately stimulated and recordings performed on 4 channels: cervical, ipsi- and contralateral parietal, and frontal. SEPs were qualitatively rated in terms of mild, moderate, or severe ipsilateral, contralateral, or bilateral abnormalities. The SEP abnormalities were subdivided into 5 categories as a function of their relationships with intraoperative events: no alterations (67.3%), early or late SEP alterations after carotid cross-clamping (15.6%), SEP alterations after a drop in blood pressure (occurring outside of or within the cross-clamping period) (15.1%), SEP alterations of a most likely embolic origin (2.4%), SEP changes after head positioning (1%), and SEP changes after a modification of the anesthetic regimen (1.5%). Only moderate to severe SEP alterations occurring soon after carotid cross-clamping justified shunt installation in 16% of the cases. SEP alterations after a drop in blood pressure were reversed merely by restoring blood pressure. The neurological outcome was uneventful in 94.2% of cases. Of the 12 patients who developed neurological sequellae, only one case presented transient sequellae after isolated CE without SEP changes while most cases either had undergone combined CE and CBP and/or VR (6 cases) or had presented SEP alterations of embolic origin (3 cases). We conclude that our system of qualitative rating of SEPs proved very sensitive to intraoperative hemodynamic disturbances or macroembolisms.
Adult↗
The usefulness of the spinal and subcortical components of the posterior tibial nerve SEPs for spinal cord monitoring during aortic coarctation repair.
This study examines how the recording of the lumbar and subcortical components of the posterior tibial nerve (PTN) SEPs may usefully replace that of cortical components in situations in which these components cannot be reliably obtained (infants, high concentrations of halogenated gasses). Lumbar, brain-stem, and cortical PTN SEPs were intraoperatively monitored in 7 patients undergoing repair of aortic coarctation under variable isoflurane concentration (up to 1.2%). Four patients were less than 1 year old. Two distinct activities were evidenced at the lumbar level in all of the patients: the dorsal root component (DRC) and the dorsal horn negativity (DHN). The equivalent of the adult P30 (lemniscal positivity; LP) was also present in all of the patients, whatever their age or the concentration of isoflurane. By contrast, the parietal activities were absent intraoperatively in the youngest patients. Spinal-cord ischemia consecutive to aortic cross-clamping gave rise to early DHN changes and later alterations of the LP in the two patients in which it occurred, while the DRC and the peripheral nerve activities remained unchanged. This elective sensitivity of the DHN is likely due to it being dependent on the gray matter of the spinal cord, the basal metabolism of which is greater than that of the white matter and to the situation of the DHN generator in a watershed zone of the spinal cord. This study emphasizes the interest of PTN SEPs for spinal-cord monitoring in vascular surgery and the importance of combining the recording of parietal activities with that of the lumbar spinal components.
Adult↗
Aortic allograft and pulmonary autograft for aortic valve replacement: mid-term results.
Between April 1990 and August 1996, 138 patients (median age 42 years, range 10 days to 66 years) underwent aortic valve or root replacement with allografts (n = 70) or autografts (n = 68). Aortic stenosis was the main indication (80 patients, 58%) followed by aortic incompetence (31 patients, 22%). Twenty-five patients had endocarditis (18%) and two patients had truncus repair (2%). Some 140 allograft valves were inserted (70 pulmonary, 70 aortic). Most of the valves were conditioned and cryopreserved by the European Homograft Bank, Brussels, Belgium. Subcoronary implantation was performed in 46 patients, intraluminal cylinder in 29 and root replacement in 63. Peroperative transoesophageal echocardiography was routinely used. Three patients required valves replacement by mechanical valves at the time of surgery due to technical failure. Seven patients (5%) died early, while 131 were followed up from 1 to 76 months (mean 32 months). There were two late deaths. All survivors are in NYHA class I and currently free of any medication. There have been no thromboembolic events. Three patients developed endocarditis (2%). Transthoracic echocardiography was performed routinely in all patients; an initial study showed grade 1 aortic incompetence in nine patients and grade 2 in two. Late studies up to 6 years after surgery showed progression of aortic incompetence in 18 of 43 survivors with subcoronary implantation and in four of 75 survivors who underwent other techniques (P < 0.002). In congenital patients with preoperative aortic incompetence, the left ventricular function has been prospectively analysed by echocardiography. Risk factors have been identified as dilated ventricles with spherical shapes, thin wall and reduced velocities by measuring ejection fraction and velocity of shortening of myocardial fibres. Allograft and autograft replacement of the aortic valve can be performed with excellent results. Considering the risk of degeneration of allografts, and the growth potential of the pulmonary autograft, this should be regarded as the optimal method of treatment for diseased aortic valves in neonates, children and young adults.
Adult↗
Is mechanical circulatory support helpful before cardiac retransplantation?
Ventricular assist devices are widely used as a bridge for cardiac transplantation patients. The purpose of the present study was to evaluate retrospectively, whether the use of ventricular assist devices could increase survival after early or late retransplantation. Over the past 10 years, 219 patients were transplanted in the authors' centre. Eight of 11 retransplanted patients required preoperative insertion of a ventricular assist device. Five assist systems were implanted in the early period after transplantation ( < 30 days) and three later after transplantation ( > 30 days). After early retransplantation, two patients survived and three died. All three late retransplantations were successful and all patients are still alive with a mean (s.d.) follow-up of 25(22) months. Ventricular assist devices are helpful for late retransplantation but do not improve poor survival after early retransplantation. Such devices should not be set up for early retransplantation.
Adult↗
Surgical angioplasty of the left main coronary artery.
OBJECTIVE: The conventional surgical treatment of isolated critical stenosis of the left main coronary artery (LMCA) leads to the definitive occlusion of LMCA, restores only a retrograde perfusion to a rather extensive myocardial area and consumes bypass material. Direct surgical angioplasty avoids these inconveniences. METHODS: Between June 1985 and August 1996, 49 surgical angioplasties have been performed in 47 patients. LMCA was approached posteriorly in the first 11 procedures, and an anterior approach was preferred in the last 38 because of better exposure. The onlay patch consisted of saphenous vein in 37 cases; pericardium was used in 12 cases, and only for ostial stenosis. RESULTS: No technical failure occurred in the last 28 cases. 44 procedures, (90%), succeeded, but 1 patient (2.3%) died later of a massive air embolism, and 2 patients needed conventional CABG after 3 and 5 months, respectively. The 35 survivors still benefiting from a successful LMCA angioplasty on the long term are free of ischemia after a mean follow-up of 75 months (2-136). Angiographic restudy was obtained in 30 patients (70%) at an average of 38 months and revealed an excellent result in 26 (87%). In 10 patients, a late angiographic restudy at an average of 71 months (32-119) still revealed a perfect result. CONCLUSION: Provided that well-defined contra-indications (involvement of the distal bifurcation, heavy calcification) are respected, LMCA surgical angioplasty deserves a place in the array of surgical strategies.
Angioplasty↗
Cross-cultural measurements of psychological well-being: the psychometric equivalence of Cantonese, Vietnamese, and Laotian translations of the Affect Balance Scale.
OBJECTIVES: This paper evaluates the cultural equivalence of Cantonese, Vietnamese, and Laotian translations of the Affect Balance Scale. METHODS: The scale was completed by 399 Vietnamese, 193 Laotian, 756 Cantonese, and 319 English speakers who were participants in the Clarke Institute-University of Toronto Refugee Resettlement Project (n = 1667). RESULTS: Confirmatory factor analyses indicated a good fit between the hypothesized two-factor model (separate factors for positive and negative affect) across the original English-language version and each of the Asian-language translations. Factorial invariance (numbers and patterns of factor loadings) was evident across all versions of the scale. No evidence of item bias was detected by mixed Language x Item analyses of variance. Acceptable reliability was observed; coefficient alphas ranged from .62 to .72 for positive affect and from .62 to .70 for negative affect items. CONCLUSIONS: These findings substantiate the cultural equivalence of the three translations of the scale for population health research. Important future research directions made possible by the availability of culturally equivalent instruments are discussed.
Adult↗