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Biomedical subjects

R Dion

Publications and source records attributed to R Dion.

At least 19 recordsLinked to original sources
PubMed2001

Complementary saphenous grafting: long-term follow-up.

OBJECTIVE: Recently we reviewed the 10-year clinical and angiographic outcomes of sequential internal thoracic artery grafting. Most of the patients also received complementary saphenous grafts, and their overall long-term patency rates were surprisingly high. Therefore, we decided to analyze these results in more detail. METHODS: The first consecutive 500 patients having received at least one sequential internal thoracic artery graft between October 1985 and August 1991 were restudied retrospectively. The saphenous grafts were only used to achieve complete revascularization in addition to complex arterial grafting on less significant or remote coronary vessels. A total of 161 patients consented to a late angiographic restudy at a mean postoperative interval of 7.5 years (1-12.2 years). RESULTS: At 5 and 10 years postoperatively, freedom from angina was 96% and 82%, and freedom from any cardiac event was 92.8% and 69%, respectively. Only 15 (3.1%) patients needed additional revascularization (0.3% per patient-year): 4 coronary artery bypass grafting (0.8%) and 11 percutaneous transluminal coronary angioplasty (2.3%). The overall patency and intactness rates of saphenous anastomoses were 72.5% and 60.2%, respectively. There was a significant difference between the patency and intactness of sequential versus single anastomoses: 76% versus 60% and 64.5% versus 44.4%, respectively. There was no significant difference in either patency or intactness between right internal thoracic and sequential saphenous grafts anastomosed to the right coronary artery: 83.4% versus 75.2% and 77.8% versus 62.4%, respectively. The same was true for the anastomoses to the "remote area" (distal circumflex, distal right coronary artery). CONCLUSIONS: Complementary sequential saphenous grafting still deserves consideration in some patients below 70 years of age, particularly for those with disease in the "remote area": the distal circumflex and right coronary branches.

Adult↗
PubMed2001

Structure of lifestyle disruptions in chronic disease: a confirmatory factor analysis of the Illness Intrusiveness Ratings Scale.

BACKGROUND: The Illness Intrusiveness Ratings Scale (IIRS) measures the extent to which disease or its treatment or both interfere with activities in important life domains. Before comparing IIRS scores within or across groups it is crucial to determine whether a common underlying factor structure exists across patient populations. OBJECTIVE: To investigate the factor structure underlying the IIRS and evaluate its stability across diagnoses. METHODS: IIRS responses from 5,671 respondents were pooled from 15 separate studies concerning quality of life in eight patient groups: rheumatoid arthritis; osteoarthritis; systemic lupus erythematosus; multiple sclerosis; end-stage renal disease (maintenance dialysis); renal transplantation; heart, liver, and lung transplantation; and insomnia. Data were gathered by different methods (eg, interview, self-administered, mail survey) and in diverse contexts (eg, individual vs. group). RESULTS: Exploratory maximum-likelihood factor analysis identified three underlying factors in a randomly selected subset of respondents (n = 400), corresponding to "Relationships and Personal Development," "Intimacy," and "Instrumental" life domains. Confirmatory factor analysis corroborated the stability of this structure in an independent subsample (n = 2100). Complementary goodness-of-fit indices confirmed the consistency of the three-factor solution, corroborating that IIRS scores are uniquely defined across patient populations. Coefficient alpha was high for total and subscale scores. CONCLUSIONS: IIRS scores can be compared meaningfully within and across patient groups. Both total and subscale scores can be used depending on research objectives.

Adult↗
PubMed2001

Hepatitis A vaccination during an outbreak among gay men in Montréal, Canada, 1995-1997.

STUDY OBJECTIVE: To evaluate an intervention designed to curtail an outbreak of hepatitis A among gay men, especially the young and sexually active, by promoting their free vaccination. DESIGN: The study analysed routine passive surveillance data, carried out questionnaire and serological surveys of vaccinees, and surveys among the target population in non-clinical venues. SETTING AND INTERVENTION: 15 000 free doses of hepatitis A vaccine were made available through clinics with large gay clienteles, or at gay events, and advertised by various means, in Montréal, Canada, from August 1996 to November 1997. Simultaneous vaccination against hepatitis B (always free for gay men) was also encouraged. PARTICIPANTS: Information was obtained from persons with the disease during the epidemic period, a sample of men requesting vaccination, and five community samples of gay men. MAIN RESULTS: The outbreak involved 376 gay men and the vaccine was distributed to approximately 10 000. Vaccinees were older than cases, but had many sex partners and comprised more food handlers. Special vaccination clinics at gay events were well attended but did not reach more high risk men than regular medical venues. A self reported vaccine coverage of 49% was achieved, but 26% of vaccinees already had anti-HAV antibodies. Disease incidence declined rapidly during the campaign. CONCLUSIONS: The intervention nearly tripled self reported hepatitis A vaccine coverage but its late start precludes proving that it caused the subsequent drop in incidence. However, it also increased hepatitis B vaccination and it is believed it improved links between gay men, public health, clinicians and community groups.

Adolescent↗
PubMed2000

Time course of functional recovery after coronary artery bypass graft surgery in patients with chronic left ventricular ischemic dysfunction.

Chronic left ventricular (LV) ischemic dysfunction, a condition often referred to as myocardial hibernation, is associated in humans with ultrastructural alterations of the myocytes, including the loss of myofilaments and the accumulation of glycogen. Given the severity of these structural changes, contractile function is unlikely to resume immediately upon revascularization. Therefore, the aim of the present study was to assess the time course of functional improvement after successful revascularization as well as its potential structural correlates. We studied 32 patients with coronary disease and chronic LV ischemic dysfunction who underwent bypass surgery. Dynamic positron emission tomography with N-13 ammonia and F-18 deoxyglucose to assess myocardial perfusion and glucose metabolism was performed in 29 patients. In all patients, a transmural biopsy was harvested from the center of the dysfunctional area, to quantify the increase in extracellular matrix and the presence of structurally altered cardiomyocytes. LV function was serially measured by digitized 2-dimensional echocardiography before and at 10 days, 2 months, and 6 months after revascularization. The time course of recovery of regional function was estimated from the monoexponential decrease in dysfunctional wall motion score. At follow-up, 19 patients had improved LV function, whereas 13 patients showed persistent dysfunction. Before revascularization, reversibly dysfunctional segments had higher myocardial blood flow (82 +/- 29 vs 53 +/- 21 ml. (min. 100 g)(-1), p = 0.044), higher glucose uptake (40 +/- 16 vs 21 +/- 9 micromol. (min. 100 g)(-1), p = 0.001), and less increase in extracellular matrix (25 +/- 15% vs 46 +/- 17%, p = 0.0008) than segments with persistent dysfunction. The extent to which function recovered was positively correlated with myocardial blood flow and negatively correlated with the increase in the extracellular matrix. In patients with reversible dysfunction, the return of segmental function was progressive and followed a monoexponential time course with a median time constant of 23 days (range 6 to 78). The rate of recovery correlated best with the proportion of altered cardiomyocytes in the biopsy. The present study thus indicates that the recovery of regional and global LV function after successful revascularization is progressive and follows a monoexponential time course that is influenced by the extent of the structural changes affecting cardiomyocytes.

Adult↗
PubMed2000

Cardiac function after intermittent antegrade warm blood cardioplegia: contribution of the double-indicator dilution technique.

OBJECTIVE: To evaluate cardiac performance following coronary artery surgery using two different techniques of cardioplegia. DESIGN: Randomized prospective study. SETTING: Adult cardiothoracic intensive care unit in a university hospital. STUDY POPULATION: Thirty patients undergoing isolated coronary surgery. INTERVENTIONS: Patients were randomized to receive either intermittent antegrade warm blood cardioplegia with normothermic bypass (group 1) or combined antegrade and retrograde cold crystalloid cardioplegia with hypothermic bypass (group 2). Hemodynamic evaluation included conventional measurements from a pulmonary artery catheter and data obtained by thermal dye dilution utilizing an arterial thermistor-tipped fiberoptic catheter. RESULTS: The only major difference between groups was a significantly higher right atrial pressure in group 2, from 4 h to 24 h after surgery (8.8 +/- 2.6 vs. 11.8 +/- 3.2 mmHg at 4 h and 11 +/- 3.1 vs. 8.5 +/- 1.8 mmHg at 24 h, P = 0.04). After cold cardioplegia a significant increase in right atrial pressure was observed (7.5 +/- 3.1 before surgery vs. 11.4 +/- 3 mmHg at 8 h, P = 0.003) whereas right ventricular end diastolic volume index did not increase significantly, suggesting impaired right ventricular diastolic compliance in this group. CONCLUSIONS: Until 24 h after surgery cold cardioplegia is associated with impaired right ventricular filling, which seems better preserved by intermittent antegrade warm blood cardioplegia. End-diastolic volume measurement with the double-indicator technique allows differentiation between systolic and diastolic dysfunction.

Analysis of Variance↗
PubMed2000

Long-term clinical and angiographic follow-up of sequential internal thoracic artery grafting.

OBJECTIVE: Sequential internal thoracic artery (ITA) grafting allows a more complete arterial revascularization of the myocardium. We wanted to verify whether the excellent clinical and angiographic short term results reported by us before where maintained over 10 years and more. METHODS: the first consecutive 500 patients having received at least one sequential ITA graft between October 1985 and August 1991 were reviewed. Age averaged 61 years. Fifty-three patients had a left ventricular ejection fraction less than 40%, 117 were not elective, 35 (7%) were reoperations, 56 (11%) had diabetes. In total 2156 anastomoses were constructed (4.3/patient), among them 1367 arterial anastomoses (2.7/patient) and 1150 sequential ITA anastomoses (2.3/patient). The clinical follow-up was 97.4% complete and averaged 9.6 (range 8.6-13.6) years. One hundred and sixty-one patients consented to a late angiographic restudy after a mean interval of 7.4 (range 1-12.2) years. RESULTS: At 5 and 10 years, 89 and 72% of the patients were still alive. At 10 years 82% are still asymptomatic and 71% free of any type of ischaemia. Only four patients (0.8%) needed a repeat surgical revascularization, and 11 (2.3%) a percutaneous coronary angioplasty. At 5 and 10 years, 92.8 and 69% of the patients remained free of any cardiac event. Overall, 95.5% of the arterial anastomoses were patent and 96.1% of the sequential ITA were patent. There was a significant difference between the patency rate of pedicled ITA and free ITA anastomoses: 96.3 vs. 86.5% (P=0.02). There was no difference in patency between left ITA and right ITA anastomoses for the LAD and Cx areas. Sequential ITA anastomoses showed excellent patency rates to all coronary vessels but the very distal circumflex and the distal branches of right coronary artery (85%). There was no significant difference between the patency of the proximal and the distal sequential ITA anastomoses. The sequential anastomoses constructed in the length tend to remain more patent than the diamond-shaped ones: 97.2 vs. 91.5% (P=0.004). CONCLUSIONS: Sequential ITA grafting optimizes arterial revascularization. The long-term patency is excellent, is identical to that of single ITA grafting, and appears not much different from postoperative patency. The need for repeat surgical and interventional revascularization has been extremely low: 3.1% over the whole follow-up.

Adult↗
PubMed2000

Intra- and postoperative factors determining neurological complications after surgery under deep hypothermic circulatory arrest: a retrospective somatosensory evoked potential study.

OBJECTIVES: Intraoperative median nerve SEP monitoring uses the disappearance of cortical and brain stem activities as the criterion to determine that brain cooling is sufficient in deep hypothermic circulatory arrest (CA) surgery. This study presents the results of a retrospective SEP analysis of intraoperative events that engendered neurological complications. METHODS: Median nerve SEP monitoring was performed on 58 consecutive patients who underwent surgery under deep hypothermic CA. The monitoring was retrospectively analyzed and compared with intraoperative events, and postoperative symptoms. RESULTS: Intraoperative SEP abnormalities were observed in 9 out of the 16 patients who presented neurological complications. Among the 7 others, the abnormalities either were present preoperatively (n = 2), occurred postoperatively (n = 3) or only involved the lower limbs (n = 2). Although the mere inspection of the intraoperative SEPs was insufficient to determine the origin of the alterations, their comparison with intraoperative events facilitated the identification of hemodynamic factors in 7 cases and embolism in two cases. There were no patients in whom CA per se caused neurological complications. CONCLUSIONS: Intraoperative SEP monitoring helps identify intraoperative events responsible for neurological complications and prevent these in subsequent procedures. However, the neurological complications of deep hypothermic CA can also be due to pre- or postoperative factors that escape the domain of intraoperative monitoring.

Adolescent↗
PubMed2000

The structure of attention-deficit and hyperactivity symptoms among native and non-native elementary school children.

This study evaluated the psychometric properties of a measure of Attention-Deficit/Hyperactivity Disorder (ADHD) with Native and non-Native children. Two models, corresponding to DSM-III-R and DSM-IV symptom categorizations of ADHD, were assessed by (a) determining which DSM schema of ADHD best fit the data within each culture group and (b) testing the cross-cultural equivalence of the best-fitting model. Data were taken from the Flower of Two Soils and School Options for Native Children studies, examinations of emotional health and academic achievement among Native and non-Native children. The studies included teacher, parent, and self-report ratings of symptoms among 1555 Native and 489 non-Native children in grades 2 and 4 at four different locations across North America. For the data derived from teacher and parent ratings, a 2-factor solution corresponding to the DSM-IV conceptualization of two subtypes provided the best fit. For student self-ratings, the 2-factor solution showed no improvement over a 1-factor model. The respective factor solutions were culturally invariant. Acceptable internal consistency was observed across raters and within culture groups.

Attention Deficit Disorder with Hyperactivity↗
PubMed2000

Surgical repair of the prolapsing anterior leaflet in degenerative mitral valve disease.

BACKGROUND AND AIM OF THE STUDY: Repair of the prolapsing anterior leaflet (AML) in degenerative mitral valve disease is more demanding than that of the posterior leaflet. We reviewed our experience in the past eight years, to examine the safety, efficacy and stability of various repair artifices. METHODS: Between January 1989 and December 1997, 102 patients (mean age 64 years; range: 26-86 years) with mitral regurgitation (MR) due to prolapse of the anterior or both mitral leaflets underwent mitral valve repair. Sixty-six patients were in NYHA class > or =III, and 94 had MR grade >II. Acute endocarditis was present in 12 patients and Barlow disease in 16. Surgical techniques consisted of chordal shortening (n = 36), chordal transposition (n = 16), papillary muscle shortening or plication (n = 10), flip-over (n = 20) and artificial chordae implantation (n = 20). RESULTS: There was no early mortality; one patient required early mitral valve replacement (MVR) for late-appearing systolic anterior motion, and one patient benefited from a successful re-repair on day 8 for partial posterior leaflet desinsertion. Mean follow up was 30 months (range: 3-92 months); there were four late deaths (two valve-related cerebrovascular accidents); two patients required re-repair (one after three months for prosthetic ring thrombosis, and one after 10 months for rupture of shortened chordae (corrected by flip-over)). Five patients had MVR between four and 32 months later: one for mitral stenosis due to posterior leaflet calcification, and four for recurrent MR due to the rupture of shortened chordae (n = 3) or plicated papillary muscle (n = 1). One patient suffered bacterial endocarditis which was treated medically. Of the 92 remaining patients with valve repair, 81 are currently asymptomatic, five are in NYHA class II and four in class III. Transesophageal echocardiographic restudy (n = 76) at a mean of 30 months after surgery revealed no MR in 68 patients, and MR of grade <II in three. CONCLUSIONS: AML prolapse repair is safe, durable, and therefore can be attempted even in mildly symptomatic patients. However, chordal shortening should be substituted by implantation of artificial chordae or by the flip-over technique.

Aged↗
PubMed2000

Transfer of the posterior leaflet of the tricuspid valve to the mitral valve.

BACKGROUND AND AIM OF THE STUDY: Coverage of large commissural defects may present a surgical challenge in mitral valve repair, for which the transfer of posterior tricuspid valve leaflet tissue is an attractive approach. METHODS: Five patients aged between 35 and 55 years underwent this procedure. After wide excision of the diseased mitral commissures, the posterior leaflet of the tricuspid valve was carefully checked, removed with its subvalvular apparatus, and transferred to the commissural area of the mitral valve. The stress on the papillary muscle suture was relieved by reinforcement of the free edge of the transferred leaflet by natural or artificial chordae. The tricuspid valve was repaired using either a sliding plasty or an annuloplasty. RESULTS: One patient who had no reinforcement of the subvalvular apparatus had a papillary muscle rupture and required mitral valve replacement during the early postoperative period. The four remaining patients remained asymptomatic and had no or trivial mitral regurgitation after a median of 13 months (range: 3-18 months), with excellent result at transesophageal echocardiography. CONCLUSION: We conclude that transfer of the tricuspid valve leaflet allows coverage of large commissural defect, and deserves a place among the surgeon's arsenal of reconstructive techniques for mitral valve repair.

Adult↗
PubMed1999

Prognostic value of myocardial ischemia and viability in patients with chronic left ventricular ischemic dysfunction.

BACKGROUND: Previous studies showed that thallium scintigraphy and dobutamine echocardiography were accurate, noninvasive ways of predicting contractile recovery after revascularization in patients with left ventricular (LV) dysfunction. However, the prognostic impact of such methods remains uncertain. METHODS AND RESULTS: We prospectively studied 137 consecutive patients with coronary disease and LV dysfunction who underwent exercise-redistribution-reinjection thallium scintigraphy and dobutamine echocardiography to identify myocardial ischemia and viability. A total of 94 patients subsequently underwent revascularization, and 43 underwent medical treatment. The primary endpoint was cardiac mortality, and mean follow-up was 33+/-10 months. Twenty-four patients died of cardiac causes. By Cox's regression analysis, long-term survival was related to the extent of coronary disease, the presence of diabetes, type of treatment, the presence of ischemic myocardium as determined by thallium scintigraphy, and the presence of viable myocardium as determined by both tests. Three-year survival was greater in patients with ischemic myocardium (as determined by thallium scintigraphy) or viable myocardium (as determined by both tests) who underwent revascularization than in the other groups (P=0.018 with thallium; P<0.001 with dobutamine). Subgroup analyses indicated that among patients with 1- or 2-vessel disease, only those with ischemic or viable myocardium improved survival after revascularization, whereas in patients with 3-vessel or left main diseases, revascularization always improved survival, albeit more in the presence of ischemic or viable myocardium. CONCLUSIONS: Among the parameters commonly available in patients with LV ischemic dysfunction, the presence of ischemic myocardium (as determined by thallium scintigraphy) and that of viable myocardium (as determined by dobutamine echocardiography) are independent predictors of subsequent mortality. These observations may be useful in the preoperative selection of patients for revascularization.

Aged↗
PubMed1999

The effect of chronic mechanical circulatory support on neuroendocrine activation in patients with end-stage heart failure.

OBJECTIVE: To evaluate if the improvement of patients supported with a Novacor was associated with a normalization in neuroendocrine activity. METHODS: Six patients had a Novacor implanted for end-stage heart failure. Four patients were transplanted after a mean of 4.5 months (range 3-6). One patient was weaned after 5 months and one died of a cerebral haemorrhage 5 weeks after implantation. Analysis of neuroendocrine activity was made prior to implantation and after 14, 30, 60 and 90 days. Levels of aldosterone, renin, cortisol, testosterone and T3 were measured using radio-immunoassays. Twenty-four hour urinary collections were made for assessment of adrenaline and noradrenaline excretion. RESULTS: Renin activity fell to normal after 14 days (16 +/- 3.0 ng/ml per h to 4.28 +/- 2.1 ng/ml per h, P < 0.05) and was maintained at 90 days. A similar picture was seen with aldosterone (1.5 +/- 0.4 nM to 0.12 +/- 0.07 nM, P < 0.05). Norepinephrine (67.46 +/- 14.1 microg/24 h) and epinephrine 12.9 +/- 2.5 microg/24 h) fell to normal physiological levels during the same time period. Cortisol levels were above normal pre-implantation but fell by day 30 (665.25 +/- 80.0 nM to 461.8 +/- 43.0 nM, P < 0.01). T3 and testosterone were lower than normal pre-implantation (T3 50 +/- 9.5 ng/dl vs. 90-200 ng/dl, testosterone 6.83 +/- 1.7 nM vs. 13-35 nM). T3 normalized after 90 days (81 +/- 11.7 ng/dl) and testosterone after 60 days (16.3 +/- 1.7 nM). CONCLUSION: Neuroendocrine function is abnormal in patients with cardiac failure who require circulatory support. The Novacor improved this, but metabolic recovery was delayed. The positive effect on the neuroendocrine axis, in the absence of activation of other endocrine systems, suggests that prolonged support may be well tolerated.

Adult↗
PubMed1998

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↗