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Biomedical subjects

J Vanhaecke

Publications and source records attributed to J Vanhaecke.

85 records · Page 5Linked to original sources
PubMed1985

Emergency bypass surgery: late effects on size of infarction and ventricular function.

Using thallium myocardial scintigraphy and radionuclide ventriculography, we assessed size of infarction and left ventricular function at late follow-up (greater than 2 months) in 13 patients who underwent emergency coronary artery bypass surgery (ECABS) during evolving myocardial infarction and in 26 controls who received conventional treatment for acute infarction. Thallium scans were quantitatively analyzed. The thallium defect, expressed as a numerical value in arbitrary units, was smaller after early revascularization (within 4 hr of the onset of symptoms, n = 10) than in the controls: 397 +/- 232 vs 2779 +/- 972 for anterior infarction (p less than .001) and 475 +/- 511 vs 1454 +/- 960 for inferior infarction (p less than .05). The patients undergoing revascularization late (4 to 5 hr after the onset of symptoms, n = 3) had thallium defects comparable to those in the controls. Regional ejection fraction of the involved left ventricular segment was higher after early revascularization (41 +/- 9% vs 21 +/- 8% for anterior infarction, p less than .005; 67 +/- 14% vs 51 +/- 11% for inferior infarction, p less than .01). Global ejection fraction was higher after early revascularization in patients with anterior infarction (57 +/- 10% vs 37 +/- 9%, p less than 0.02), but not in those with inferior infarction (60 +/- 11% vs 54 +/- 8%, p greater than .05). After late revascularization, regional and global ejection fraction were comparable to those in controls. In selected patients, early reperfusion of acutely ischemic myocardium by ECABS can limit size of infarction and preserve left ventricular function, but time constraints may be severe.

Adult↗
PubMed1983

Angiographic evolution of coronary atherosclerosis in non-operated patients.

Repeat coronary arteriography was performed in 100 patients with angiographically proven coronary artery disease, because of worsening symptoms (n = 67), persistent stable angina (n = 22) or other reasons (n = 11). The mean interval between the studies was 34.6 months (range 6-99). No patient had interim coronary artery bypass surgery. Progression of coronary artery disease was demonstrated in 60 patients and was correlated in bivariate analysis with the time interval between coronary arteriograms (P less than 0.0001) and with the interim clinical evolution (P less than 0.01). The incidence of progression was similar in the coronary arteries. Moderate lesions (40-70% narrowing) had the highest progression percentages. New significant lesions in previously normal arterial segments were rare. A multivariate analysis of 18 possible predictors revealed three independent variables correlated with progression of coronary artery disease: time interval (P less than 0.0001) and change in functional class (P less than 0.02) between coronary arteriograms, as well as the presence of clinical diabetes (P less than 0.03). Other risk factors and a change of individual risk factors between coronary arteriograms were not correlated with progression of coronary artery disease. Using the results of the multivariate analysis, the evolution of coronary artery disease was correctly predicted in only 72 patients. Following the repeat coronary arteriogram, coronary artery bypass surgery was proposed to 62 patients, 26 of whom needed more distal anastomoses for optimal myocardial revascularization. Because of the important therapeutic implications and the lack of reliable predictors, an aggressive follow-up of patients with known coronary artery disease seems warranted.

Adult↗
PubMed1981

Coronary arterial lesions in young men who survived a first myocardial infarction: clinical and electrocardiographic predictors of multivessel disease.

An analysis was made of clinical and electrocardiographic prognostic determinants of multiple vessel disease in 100 men, aged under 45 years, who survived a myocardial infarction. All patients underwent selective coronary arteriography within 1 year after sustaining a myocardial infarction. Multivessel disease was present in 64 patients; 33 patients had single vessel disease and 3 had either normal coronary arteries or minimal lesions. Exercise stress testing, electrocardiographic location of the infarction, total serum cholesterol and clinical features including body build, arterial blood pressure, smoking habits, family history of coronary artery disease and the presence of angina pectoris either before or after the acute event proved to be poor predictors of multiple vessel disease. Only 74 percent of the patients were correctly classified by a discriminant function analysis. Thus, for prognostic reasons, coronary arteriography seems warranted in young patients after acute myocardial infarction, even in the absence of residual angina or multiple risk factors.

Adult↗
PubMedDate not supplied

Tibial osteomyelitis due to Aspergillus flavus in a heart transplant patient.

Aspergillus flavus was identified as the causative organism of a case of osteomyelitis involving the proximal epiphysis of the left tibia in a heart transplant patient. History revealed a previous pretibial wound due to a fall in the street as the consequence of a sudden cardiac arrest. Surgical debridement combined with fungostatic treatment including amphotericin B and itraconazole was followed by clinical improvement, although the fungus could still be recovered by culture on subsequent samples.

Amphotericin B↗
PubMedDate not supplied

Prevention of the "no reflow" phenomenon in the canine heart by mioflazine.

The effects of oral pretreatment with mioflazine (2.5 mg X kg-1) on regional myocardial reflow, infarct size reduction and hemodynamic recovery were studied in 24 anesthetized open-chest dogs undergoing 90 minutes of acute left anterior descending coronary artery (LAD) occlusion followed by 150 minutes of reperfusion. Regional myocardial blood flow was measured with tracer microspheres, and infarct size was determined by triphenyl tetrazolium chloride staining. Pretreatment with mioflazine resulted in a reduced diastolic aortic pressure (p less than 0.05) and an elevated cardiac output and LV dpdt max (p less than 0.05). These effects persisted throughout the experiment. In control animals (n = 12) a hyperemic reflow response was found in the perfusion area of the LAD during the first minutes of reperfusion. After 150 min of reperfusion, however, the viable myocardium of the LAD area became underperfused, and almost no reflow was found in the infarcted zones. In the animals pretreated with mioflazine (n = 12) the hyperemic response persisted throughout the reperfusion phase and the no-reflow phenomenon was prevented. Infarct size (expressed as percentage of perfusion area) tended to be smaller in this group: 23.7 +/- 12.4% versus 33.7 +/- 19.2% (p greater than 0.05). Left atrial pressure increased during LAD occlusion in both groups but normalized completely in the drug-pretreated animals (p less than 0.05). It is concluded that pretreatment with mioflazine prevents the no-reflow phenomenon after reperfusion of an evolving infarction, tends to reduce infarct size and improves hemodynamic recovery.

Animals↗
PubMedDate not supplied

Determinants of infarct size in non-human primates.

To achieve a better understanding of the major factors that determine infarct size in non-human primates, a mathematical model was constructed using stepwise regression analysis. The model was developed on the basis of infarct size measurements, including the anatomical area at risk, regional myocardial blood flow measurements and hemodynamic determinants obtained in 23 control baboons undergoing up to 2 h of coronary artery thrombosis followed by thrombolysis. In this model, the size of the perfusion bed of the occluded coronary artery and the duration of coronary artery occlusion were found to be the only important predictors of infarct size (expressed as a percentage of left ventricular mass). R2 (square or the multiple correlation coefficient) was 70% in this model. Collateral blood flow and rate-pressure product were not identified as important predictors of infarct size. In a second group of eight baboons, atenolol (0.1 mg.kg-1) was administered intravenously 15 min after the onset of coronary artery thrombosis. Predicted infarct size (based on the mathematical model obtained in the control group) was larger than the observed infarct size in seven out of eight cases. In four instances observed infarct size was smaller than the 95% lower limit of the predicted value. It is concluded that the determinants of infarct size in non-human primates differ from those in canine models with respect to collateral flow and estimates of myocardial oxygen consumption (rate pressure product). The developed mathematical model of infarct size prediction allows the detection of cardioprotective drug effects with an acceptable efficacy.

Animals↗
PubMedDate not supplied

A comparison of two methods for estimating the area at risk in experimental myocardial infarction.

In a canine model of coronary artery occlusion and reperfusion, we assessed the amount of myocardium at risk for necrosis using both post-mortem perfusion staining with triphenyltetrazolium-chloride (TTC) and autoradiography following in vivo injection of 141Ce microspheres. Twenty-four transverse slices of 5 dog hearts were analyzed. In the same heart slice planimetry was performed both on the calibrated colour picture taken after TTC staining (A) and on the autoradiogram (B). The values for the area at risk, as determined by both methods, were very closely correlated and almost identical: A = 0.977 B + 31.4 mm2, r = 0.99, p less than 0.001. This is in contrast to an earlier report where a different autoradiographic technique was used. In short-term experimental models of coronary artery occlusion, autoradiography delineates an area at risk, matching very closely the area at risk obtained after TTC staining.

Animals↗
PubMedDate not supplied

Time constraints in the emergency coronary bypass surgery for acute evolving myocardial infarction.

Fourty four patients underwent emergency coronary grafting for evolving myocardial infarction. All patients but one had undergone coronary angiography before the new infarction, 50% were in cardiogenic shock or under cardiopulmonary resuscitation. The mean time interval between the onset symptoms and opening of the bypass to the threatened area was 171 minutes. The operative mortality was 6.8%. At 30 months after surgery, the cardiac actuarial survival was 93.2%, the angina free group 94.2% of the operative survivors. Infarct size and regional ejection fraction of these patients at late follow-up were compared to those of controls treated conventionally for acute infarction. The thallium defects were smaller and the regional ejection fraction of the involved segment was higher after early surgery (less than 3 hours ischemia) than in controls. In the late surgery group the thallium defects and the regional ejection fractions were similar. Ultrastructural studies on biopsy samples taken from the center of the threatened area show reversible changes in the early surgery group but irreversible mitochondrial damage and cell membrane rupture in the late surgery group. Biochemical analysis of similar cardiac biopsies shows recovery after one hour empty beating reperfusion but only in the early surgery group. Our results suggest that coronary surgery can be beneficial to the patient with an evolving myocardial infarction, if the clinical situation does not permit intracoronary thrombolysis. However, one hour reperfusion of the empty beating heart before weaning off bypass is essential. The time constraints for both emergency surgery or thrombolysis are similar.

Adult↗
PubMedDate not supplied

Hospital costs of protective isolation procedures in heart transplant recipients.

BACKGROUND: This study details the hospital costs of strict reverse isolation procedures in heart transplant recipients. METHODS: In a prospective, descriptive design, a research protocol was developed, identifying all of the activities related to strict reverse isolation procedures in heart transplant recipients. For each separate activity, materials used and workload were registered, which allowed the calculation of the material and labor costs for each of the isolation procedures. RESULTS: The cost calculations show that the first day in isolation costs about $160 (for isolation procedures only) and about $65 for each consecutive isolation day. With a mean post-intensive care unit length of stay of 22 days, the mean cost of isolation procedures for heart transplant recipients amounts to $1535. Finally, a modified isolation protocol was developed, incorporating only those procedures with proven effectiveness. It was calculated that a switch to such a modified protocol would allow a savings of over 50% of the hospital resources devoted to isolation measures. CONCLUSIONS: Isolation procedures use a significant portion of hospital resources. Modifying isolation protocols in heart transplant recipients can be a source of considerable savings in a transplant program.

Belgium↗
PubMedDate not supplied

Dobutamine stress echocardiography after heart transplantation.

Dobutamine stress echocardiography was performed in 28 heart transplant recipients to study its value in the detection and staging of transplant vasculopathy. Fourteen patients had angiographic evidence of coronary artery disease (group 1), and 14 had angiographically normal coronary arteries (group 2). The dobutamine stress protocol called for a dose increase of dobutamine every 3 minutes until the age-predicted maximal heart rate was achieved. In groups 1 and 2, the mean maximal dose of dobutamine was, respectively, 24 +/- 9 micrograms/kg min and 29 +/- 8 micrograms/kg min, and the mean rate-pressure product was, respectively, 12386 +/- 1777 mm Hg/min and 10753 +/- 1085 mm Hg/min at rest, increasing to 20987 +/- 4020 mm Hg/min and 19795 +/- 2728 mm Hg/min at maximal dose. No patient in group 1 or 2 had deterioration of global or regional wall motion under dobutamine stress. In group 1, seven patients had wall motion abnormalities at rest, normalizing in five of them under dobutamine stress. In group 2, four patients had wall motion abnormalities at rest, normalizing in all patients under dobutamine stress. Consequently, this protocol of dobutamine stress echocardiography is unsuitable for the early detection of transplant vasculopathy despite its proven value in the general population. Conversely, these data suggest that the functional sequelae of transplant vasculopathy are not necessarily prominent, despite the known angiographic underestimation of the extent of the disease.

Blood Pressure↗
PubMedDate not supplied

Hemopump fails as bridge to transplantation in postinfarction ventricular septal defect.

From 1990, six patients were bridged to transplantation with a catheter-mounted axial flow pump (Hemopump). Indications were graft failure (two patients), postinfarction ventricular septal defect (two patients), myocarditis (1 patient), and myocardial infarction (1 patient). The 21F cannula, inserted via the groin, was used as a partial assist in four patients, and the 31F cannula, inserted via the ascending aorta, was used to assist the other two patients completely. Hemodynamic recovery was achieved in all patients (mean cardiac index rose from 2.1 L/gm/m2 to 3.85 L/gm/m2 after 1 hour assist). Sudden pump failure occurred in the two patients with postinfarction ventricular septal defect and a piece of necrotic tissue blocking the catheter was found. Both patients died. The other four patients were successfully bridged to transplantation. One of these patients died during his postoperative hospital stay; the three remaining patients were discharged and were well at follow-up (46, 40, and 3 months). The Hemopump device provides sufficient organ perfusion to be used as a bridge to transplantation. No conclusions can be drawn for the long-term use (longest run in this series was 102 hours). Postinfarction ventricular septal defect is a contraindication for the use of the Hemopump device.

Adolescent↗