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Biomedical subjects

P Coriat

Publications and source records attributed to P Coriat.

At least 19 recordsLinked to original sources
PubMed1996

Oxygen consumption and delivery relationship in brain-dead organ donors.

The oxygen delivery (DO2) and consumption (VO2) relationship in brain-dead organ donors is unknown. Therefore, in a prospective study, we determined the DO2/VO2 relationship in 21 consecutive brain-dead patients. Patients were allocated to one of two groups, according to plasma lactate concentration: normal (group NL, n = 11) or high (> 2.5 mmol litre-1) (group HL, n = 10). VO2 was measured independently, using indirect calorimetry, under control conditions, during low DO2 challenge with PEEP administration, and high DO2 challenge with inflation of medical antishock trousers and volume expansion or blood transfusion, as required. Under control conditions, there were no significant differences between groups NL and HL in haemodynamic or oxygenation variables, both groups having a low VO2 (mean 114 (SD 21) ml min-1 m-2). In group HL there was a different DO2/VO2 relationship pattern, with a dependent VO2 only. The mean slope of the DO2/VO2 relationship was significantly higher in group HL than in group NL (0.12 (0.09) vs 0.04 (0.07), P < 0.05). We conclude that brain death was associated with a low VO2, and patients in group HL exhibited DO2/VO2 dependency which was not observed in patients in group NL.

Adolescent↗
PubMed1996

The effects of triiodothyronine on hemodynamic status and cardiac function in potential heart donors.

Brain death is associated with altered cardiac function and low concentrations of circulating triiodothryronine (T3). However, the effects of T3 administration on hemodynamic status and cardiac function in potential heart donors remain controversial. Thirty-seven brain-dead patients were randomly and blindly allocated to receive an intravenous bolus of either 0.2 microgram/kg T3 (n = 19) or saline placebo (n = 18). Measurements included conventional hemodynamic and echocardiographic variables of cardiac volume conditions and systolic function of the left ventricle (fractional area change [FAC], velocity of myocardial fiber shortening) using a transesophageal probe, arterial and mixed venous blood gas parameters, and serum thyroid hormone concentrations. The mean concentration of T3 was 1.86 +/- 1.55 pmol/L, and only six patients (16%) had normal values of T3 in control conditions. There was no significant correlation between T3 concentration and FAC (R = 0.17, not significant). All patients receiving T3 had normalized serum T3 concentration (7.55 +/- 2.56 pmol/L) in contrast to patients receiving saline (1.48 +/- 1.26 pmol/L). No significant differences in hemodynamic and echocardiographic parameters were observed between the placebo and T3 groups. Indeed, FAC remained unchanged after T3 (44% +/- 17% vs 46% +/- 22%) or placebo (47% +/- 18% vs 50% +/- 14%) administration. In 20 patients with impaired left ventricular function (FAC < 50%), FAC remained unchanged after T3 (n = 10; 34% +/- 12% vs 30% +/- 10%) or placebo (n = 10; 38% +/- 12% vs 35% +/- 13%) administration. In 17 patients in whom organ harvesting was delayed, transesophageal echocardiography was performed 6 h later and no significant changes in FAC were noted in the T3 group (n = 8; 49% +/- 17% vs 44% +/- 17%) and the placebo group (n = 9; 51% +/- 18% vs 47% +/- 18%). In conclusion, T3 administration did not improve hemodynamic status and myocardial function in brain-dead patients, suggesting that the euthyroid sick syndrome is not the main determinant of myocardial dysfunction in these patients.

Adolescent↗
PubMed1996

Fluoride ion toxicity in human kidney collecting duct cells.

BACKGROUND: Several halogenated anesthetics induce a urinary concentrating defect, partly related to fluoride ion toxicity in collecting duct cells. The aim of this study was to investigate the effects of fluoride ion in human kidney cells. METHODS: Immortalized human collecting duct cells were used. In a first set of experiments, the toxicity threshold concentration was determined by exposing cell cultures for 24 h to increasing concentrations of fluoride ion in the medium: 0, 1, 5, and 10 mM. The second set of experiments was a time- effect study in which cells were exposed to 5 mM fluoride for 2, 6, and 24 h. Assessment of toxicity was based on several endpoints: cell number, protein content, (3)H-leucine incorporation in newly synthesized proteins, extracellularly released lactate dehydrogenase, Na-K-ATPase pump activity, and electron microscope studies. RESULTS: After 24 h of exposure, fluoride ion decreased cell number (-23%, P<0.05), total protein content (-30%, P<0.05) and increased lactate dehydrogenase release (+236%, P<0.05) at a threshold concentration of 5mM. Fluoride ion also inhibited Na-K- ATPase activity at 5 mM (-58%, P<0.05). Major morphologic alterations of mitochondria, including crystal formation, were detected from 1 mM fluoride concentration. Time-effect studies showed that, after only 6 h of exposure at 5 mM, fluoride decreased cell number (-13%, P<0.05), (3)H-leucine incorporation (-48%, P<0.05), and Na-K-ATPase activity (- 20%, P<0.05) and increased lactate dehydrogenase release (+145%, P<0.05). Crystal deposits in mitochondria again were a more sensitive marker of cell injury, detectable after only 2 h of exposure. CONCLUSIONS: these results suggest that the mitochondrion is a target of fluoride toxicity in human collecting duct cells, and its alteration is partly responsible for the sodium and water disturbances observed in patients.

Anesthetics, Inhalation↗
PubMed1995

[Comparison of the effects of ketorolac and aspirin on hemostasis in the rabbit].

OBJECTIVE: Comparison of ketorolac with aspirin and placebo for the antithrombotic activity using the Folts' model of experimental arterial thrombosis and the perioperative blood loss. STUDY DESIGN: Experimental randomized blinded study anaesthetized, tracheotomized and mechanically ventilated. Carotid blood flow variations were detected by a probe directly inserted around the artery and monitored by an electromagnetic flowmeter. A segment of the exposed carotid artery was de-endothelialized by gently squeezing the artery with a needle holder forceps, and an external constrictor was placed around it (stenosis 60%), to induce cyclic flow reductions (CFR). During 20 min, CFR rate was assessed. Animals were then randomized in 3 groups of 9: ketorolac (K) 1 mg.kg-1, aspirin (A) 10 mg.kg-1 or saline (S), injected intravenously (peripheral ear vein). After drug administration, CFR rate was assessed over 20 min, to determine the potential antithrombotic activity of the drug (curative phase). Thereafter, the opposite carotid artery was injured and stenosed and the occurrence of CFR was assessed over 20 min (preventive phase). The amount of blood loss of a xipho-pubic laparotomy with a spleen section was also measured 30 min after drug administration. RESULTS: In all untreated animals, CFRs developed with a mean rate of 4 cycles/20 min. Aspirin completely abolished CFR during the curative phase in all rabbits, except in one. No effect was observed during this phase with ketorolac or saline. During the preventive phase, a partial inhibition of CFRs was induced by ketorolac and aspirin. Peri-operative bleeding was not increased significantly by ketorolac or aspirin. Postinjection bleeding-time did not differ between the three groups. CONCLUSIONS: Ketorolac (1mg.kg-1) has not a strong antithrombotic activity. Ketorolac and aspirin do not increase peri-operative blood loss, and therefore do not seem to strongly interfere with haemostasis in the rabbit.

Animals↗
PubMed1995

Determinants of systolic pressure variation in patients ventilated after vascular surgery.

OBJECTIVE: To discover the predominant determinant of systolic pressure variation during positive-pressure ventilation in mechanically ventilated patients after a vascular surgical procedure. DESIGN: Case control study. SETTING: Postanesthesia care unit at a university hospital. PARTICIPANTS: Eleven patients who were sedated during mechanical ventilation after abdominal aortic surgery. INTERVENTIONS: Radial arterial pressure and airway pressure were simultaneously recorded. The systolic pressure variation was measured as the mean difference between the maximal and minimal systolic pressure values during five consecutive mechanical breaths. The delta down was measured as the difference between the systolic blood pressure during apnea and the minimal values of the systolic pressure after one mechanical breath. The velocity time integral, which is closely related to stroke volume, was measured throughout the systolic pressure measurements. MEASUREMENTS AND MAIN RESULTS: Positive correlation was found between changes in velocity time integral and the magnitude of both systolic pressure variation (r = 0.73) and delta down (r = 0.80). Volume loading did not significantly modify systolic blood pressure. However, it did not significantly decrease systolic pressure variation and delta down. The corresponding changes in velocity time integral provoked by mechanical ventilation decreased significantly as well. CONCLUSIONS: The decrease in systolic pressure provoked by positive-pressure inspiration reflects simultaneous decreases in stroke volume. This suggests that a decrease in left ventricular filling, associated with positive-pressure inspiration, is responsible for systolic pressure variation. This finding confirms the interest in considering systolic pressure variation to provide reliable information about the responsiveness of the heart to preload variations.

Aged↗
PubMed1995

Inhibition of platelet aggregation by inhaled nitric oxide in patients with acute respiratory distress syndrome.

BACKGROUND: Nitric oxide inhibits platelet adhesion and aggregation in vitro. The aim of this prospective study was to assess the platelet antiaggregating activity of nitric oxide administered to patients with acute respiratory distress syndrome (ARDS) at increasing concentrations. METHODS: In six critically ill patients (mean age 37 +/- 16 yr) with ARDS (lung injury severity score > or = 2.2), the lungs were mechanically ventilated with inhaled nitric oxide (1, 3, 10, 30, and 100 ppm) randomly administered. Patients with cardiac dysrhythmias, septic shock, an underlying hemostasis disorder (constitutive or acquired), a platelet count less than 100 Giga/l, or a decreased platelet aggregation and those treated with antiplatelet or anticoagulant agents were excluded. Platelet aggregation was measured without nitric oxide and at each nitric oxide concentration in platelet-rich plasma issued from radial artery. Ivy bleeding time using a horizontal incision was simultaneously performed. RESULTS: After nitric oxide, a non-dose-dependent but statistically significant decrease in ex vivo platelet aggregation induced by three aggregating agents was observed: adenosine diphosphate = -56 +/- 18%, collagen = -37 +/- 18%, and ristocetin = -45 +/- 18% (P < 0.05). In each individual, Ivy bleeding time remained within normal values measured in healthy volunteers, and variations after nitric oxide did not correlate with changes in platelet aggregation. Simultaneously, arterial oxygenation improved significantly and pulmonary artery pressure decreased significantly. CONCLUSIONS: In patients with ARDS and without preexisting coagulation disorders, the beneficial effects of inhaled nitric oxide on arterial oxygenation and pulmonary circulation are associated with a significant inhibition of platelet aggregation. This antithrombotic effect is not associated with a significant prolongation of the bleeding time.

Acute Disease↗
PubMed1995

Dose-response curves of inhaled nitric oxide with and without intravenous almitrine in nitric oxide-responding patients with acute respiratory distress syndrome.

BACKGROUND: Inhaled nitric oxide, a selective pulmonary vasodilator, in combination with intravenous almitrine, a selective pulmonary vasoconstrictor, markedly improves arterial oxygenation in 50-60% of patients with acute lung injury. The goal of this study was to assess dose response of inhaled nitric oxide with and without almitrine in patients with acute respiratory distress syndrome responding to nitric oxide. METHODS: Six critically ill patients (aged 44 +/- 7 yr) were studied during early stage of their acute respiratory failure (Murray score: 2.6 +/- 0.1). All responded to 15 parts per million (ppm) of inhaled nitric oxide by an increase in Pao2 of at least 40 mmHg at FIo2 1. Hemodynamic and respiratory parameters were recorded continuously from pulmonary artery and systemic catheters. Inspiratory, expiratory, and mean intratracheal nitric oxide concentrations were monitored continuously using a fast response time chemiluminescence apparatus (NOX 4000, Sérès, Aix-en-provence, France). On day 1, 6 inspiratory concentrations of nitric oxide were randomly administered: 0.15, 0.45, 1.5, 4.5, 15, and 45 ppm to determine the dose response of inhaled nitric oxide on Pao2, pulmonary shunt, mean pulmonary artery pressure, and pulmonary vascular resistance index. On day 2, a continuous intravenous infusion of almitrine at a dose of 16 micrograms.kg-1.min-1 was administered and dose response to inhaled nitrix oxide was repeated according to the same protocol as during day 1. A constant FIo2 of 0.85 was used throughout the study. RESULTS: Nitric oxide induced a dose-dependent increase in Pao2 for inspiratory nitric oxide concentrations ranging between 0.15 and 1.5 ppm. Almitrine increased Pao2/FIo2 from 161 +/- 30 to 251 +/- 45 mmHg (P < 0.001) and pulmonary vascular resistance index from 455 +/- 185 to 527 +/- 176 dyn.s.cm-5.m2 (P < 0.05), and decreased pulmonary shunt (Qs/QT) from 35 +/- 2 to 33 +/- 3% (P < 0.001). During almitrine combined with nitric oxide, a dose-dependent increase in Pao2 was observed for inspiratory nitric oxide concentrations ranging between 0.15 and 1.5 ppm. Almitrine plus nitric oxide 1.5 ppm increased Pao2/FIo2 from 161 +/- 30 to 355 +/- 36 mmHg (P < 0.001), decreased Qs/QT from 35 +/- 2 to 24 +/- 2% (P < 0.001), pulmonary vascular resistance index from 455 +/- 185 to 385 +/- 138 dyn.s.cm-5.m2 (P < 0.05), and mean pulmonary artery pressure from 31 +/- 4 to 28 +/- 4 mmHg (P < 0.001). CONCLUSIONS: In 6 patients with early acute respiratory distress syndrome and highly responsive to inhaled nitrix oxide, the administration of intravenous almitrine at a concentration of 16 micrograms.kg-1.min-1 induced an additional increase in Pao2. Dose response of nitric oxide was not changed by the administration of almitrine and a plateau effect was observed at inspiratory nitric oxide concentrations of 1.5 ppm.

Administration, Inhalation↗
PubMed1995

Circulatory effects of desflurane.

The cardiovascular properties of desflurane and some other inhalational anaesthetics are outlined and compared, and the way in which they may be effectively used in clinical practice is considered. Desflurane appears to offer some advantages compared with currently available anaesthetics. Its effects on left ventricular function are moderate and the solubility of the agent in blood and tissue is remarkably less than isoflurane, enflurane, or halothane.

Anesthesia↗
PubMed1994

Dipyridamole-thallium scintigraphy and gated radionuclide angiography to assess cardiac risk before abdominal aortic surgery.

BACKGROUND: Because many patients with atherosclerotic disease of the abdominal aorta also have coronary artery disease, assessment of cardiac risk before abdominal aortic surgery has received much attention. Our prospective study was designed to identify predictors of cardiac risk in consecutive patients evaluated preoperatively with dipyridamole-thallium single-photon-emission computed tomography (SPECT) to assess myocardial perfusion and radionuclide angiography to measure left ventricular ejection fraction. METHODS: Clinical and scintigraphic data were collected prospectively during hospitalization in 457 consecutive patients undergoing elective abdominal aortic surgery. Adverse cardiac outcomes were predicted with multivariate analyses. RESULTS: Eighty-six patients (19 percent) had one or more of the following postoperative complications: prolonged myocardial ischemia (61 patients), myocardial infarction (22), congestive heart failure (20), and severe ventricular tachyarrhythmia (2). Twenty patients died postoperatively (4.4 percent), half of them from cardiac causes. Information about myocardial perfusion obtained from dipyridamole-thallium SPECT did not accurately predict adverse cardiac outcomes. The best correlates of cardiac complications were definite clinical evidence of coronary artery disease (odds ratio, 2.6; 95 percent confidence interval, 1.6 to 4.3) and age greater than 65 years (odds ratio, 2.3; 95 percent confidence interval, 1.4 to 3.6). Measurement of the ejection fraction was useful only in the prediction of left ventricular failure. Age greater than 65 years was the only predictor of death (odds ratio, 26.4; 95 percent confidence interval, 3.5 to 200.0). CONCLUSIONS: The presence of definite clinical evidence of coronary artery disease and older age were the most important preoperative predictors of an adverse cardiac outcome after abdominal aortic surgery. These results suggest that the routine use of dipyridamole-thallium SPECT and radionuclide angiography for screening before abdominal aortic surgery may not be justified.

Aged↗
PubMed1994

Aprotinin to decrease bleeding and intraoperative blood transfusion requirements during descending thoracic and thoracoabdominal aortic aneurysmectomy using cardiopulmonary bypass.

The purpose of this retrospective study was to assess the efficacy of aprotinin, an antifibrinolytic agent, in reducing bleeding and blood transfusion requirements in patients undergoing descending thoracic or thoracoabdominal aortic aneurysmectomy using cardiopulmonary bypass (CPB). Sixty-nine consecutive patients underwent thoracic or thoracoabdominal aneurysmectomy using CPB in a 2-year period. None of the 29 patients operated on in 1990 (group 1) received aprotinin, whereas all 40 patients operated on in 1991 (group 2) were placed on a high-dose regimen of aprotinin. There were no significant differences between the two groups. Administration of aprotinin was associated with a decrease in CPB time (p = 0.02), surgical duration (p = 0.05) and intraoperative blood loss (p = 0.008) as well as a reduction in intraoperative packed red cells (p = 0.01), Cell-Saver units (p = 0.05), fresh-frozen plasma units (p = 0.002), and platelet concentrate (p = 0.01) requirements. These data suggest that aprotinin is effective in reducing bleeding and blood transfusion requirements during descending thoracic or thoracoabdominal aortic aneurysmectomy using CPB.

Adult↗
PubMed1994

Influence of chronic angiotensin-converting enzyme inhibition on anesthetic induction.

BACKGROUND: Several cases of hypotension have been reported in patients who received angiotensin-converting enzyme inhibitors (ACEIs) before a surgical procedure, suggesting that interactions between ACEIs and anesthesia may be neither beneficial nor predictable. To determine if continuation of ACEI therapy until the morning of surgery leads to an unacceptable decrease in blood pressure on induction, we investigated 51 vascular surgical patients that were chronically treated for hypertension with either captopril or enalapril. METHODS: After randomization, ACEI therapy was either continued until the morning of surgery or stopped at the time of the preanesthetic visit, at least 12 h (captopril) or 24 h (enalapril) before surgery. Each patient received a standardized anesthetic induction. If systolic blood pressure (monitored using a radial artery cannula) decreased to less than 90 mmHg in response to induction, ephedrine was administered. RESULTS: A marked decrease in plasma converting-enzyme activity was found in patients who received enalapril until the morning of the surgical procedure, and 100% of them required ephedrine after induction. In patients who received their usual dose of captopril on the morning of surgery, plasma converting-enzyme activity was reduced to a lesser extent (when compared with patients who received enalapril). Finally, in the patients in whom ACEI therapy, either enalapril or captopril, was stopped of the evening before surgery, the incidence of induction-induced hypotension was significantly less when enalapril or captopril therapy has been discontinued. CONCLUSIONS: These data indicate that in hypertensive patients chronically treated with ACEIs, maintenance of therapy until the day of surgery may increase the probability of hypotension at induction.

Anesthesia↗
PubMed1994

High-frequency jet ventilation vs continuous positive airway pressure for differential lung ventilation in patients undergoing resection of thoracoabdominal aortic aneurysm.

Twenty patients, scheduled for surgical resection of thoracoabdominal aortic aneurysm were divided into two groups according to the type of differential lung ventilation used during graft replacement of the descending thoracic aorta. In the high-frequency jet ventilation (HFJV) group of ten patients, HFJV was applied to the left lung once collapsed and retracted by the surgeon, the patient lying in the right lateral decubitus and being intubated by a Carlens' tube. In the continuous positive airway pressure (CPAP) group of ten patients, CPAP was applied to the left lung at the same mean airway pressure as HFJV (1 kPa). Before anaesthetic induction, an arterial and a Swan-Ganz catheter were inserted for cardiovascular monitoring. The same anaesthetic technique using fentanyl 6 micrograms.kg-1, flunitrazepam 0.02 mg.kg-1 and pancuronium 0.1 mg.kg-1 was used for each patient. Haemodynamic and respiratory measurements were made; 15 min after positioning the patients in the right lateral decubitus using two-lung ventilation; 15 min after collapse and retraction of the left lung using one-lung ventilation and 15 min after using differential lung ventilation with CPAP or HFJV. Left lung collapse with conventional one-lung ventilation induced a dramatic decrease in arterial oxygenation: PaO2/FIO2 ratio decreased from 43 +/- 6 kPa to 20 +/- 8 kPa, alveolo-arterial oxygen difference increased from 24 +/- 7 kPa to 72 +/- 11 kPa and pulmonary shunt increased from 17 +/- 2% to 37 +/- 3%. Whereas differential lung ventilation with CPAP did not improve any of the respiratory parameters measured, differential lung ventilation with HFJV, significantly increased PaO2/FIO2 ratio to 41 +/- 14 kPa.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

A comparison of systolic blood pressure variations and echocardiographic estimates of end-diastolic left ventricular size in patients after aortic surgery.

As suggested by experimental studies, systolic pressure variation (SPV), the difference between maximum and minimum values of systolic blood pressure after a single positive pressure breath, may be a fair indicator of left ventricular preload. SPV was quantified in 21 patients who had undergone abdominal aortic surgery and were sedated under mechanical ventilation. The aim of the study was to assess the ability of this parameter to qualitatively estimate left ventricular preload measured using transesophageal echocardiography. All patients had preoperative radionuclide ejection fraction > 45%. Postoperative mechanical ventilatory patterns were the same for all patients: tidal volume = 10 mL/kg; respiratory frequency = 12-14 breaths/min; and zero end-expiratory pressure mode. Left ventricular dimensions at end-diastole correlated well with the magnitude of both SPV (r = 0.80) and its delta down (dDown) component (i.e., the degree by which systolic pressure decreases with each mechanical breath) (r = 0.83). Once the first measurement was completed, volume loading with two increments of 250 mL of human albumin 5% was performed in all but three patients. Each volume loading step caused a significant increase in the end-diastolic area (EDa) index (7.0 +/- 1.6 to 8.5 +/- 1.6 cm2/m2) and cardiac index (CI) (3.1 +/- 0.9 to 4.1 +/- 0.9 L.min-1 x m-2) and a concomitant significant decrease in the SPV (8.6 +/- 4.5 to 6.1 +/- 3.7 mm Hg) and its dDown component (5.9 +/- 4.1 to 2.9 +/- 2 mm Hg).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

[Interferences between angiotensin-converting enzyme inhibitors and spinal anesthesia].

To determine whether angiotensine converting enzyme inhibition (ACEI) therapy should be continued up to the time of the surgical procedure, a standard practice for other modern antihypertensive agents, it should be known whether stopping the treatment does or does not lead to a hypertensive episode before surgery or at intubation and whether continuing treatment is or is not associated with an unacceptable fall in blood pressure at induction. Data from the literature obtained in patients chronically treated for essential hypertension with captopril or enalapril demonstrate that withdrawal of ACEI therapy before surgery does not result in a higher incidence of hypertensive episodes both preoperatively and at intubation. In contrast, an increased need for ephedrine to maintain blood pressure at induction is observed in patients who receive ACEI together with their premedication. This exaggerated hypotensive response to induction is in agreement with previous studies in anaesthetized subjects which have shown that angiotensin II contributes to hemodynamic regulation during general and epidural anaesthesia. It might also be the consequence of the specific effects of ACEI therapy on the loading conditions of the heart and/or the autonomic nervous system. It must be emphasized that both ACEIs and epidural anaesthesia dilate large arteries as capacitance vessels and increase vagal tone. The decreased tone in capacitance vessels accentuates the drops in blood pressure provoked by general or epidural anaesthesia through an increase in blood pooling at the expense of cardiac filling. This mechanism is enhanced by the presence of either a preoperative hypovolemia or a disturbed left ventricular diastolic function, which are two abnormalities frequently seen in hypertensive vascular surgical patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Epidural↗
PubMed1994

Evaluation of the effects of rocuronium bromide on haemodynamics and left ventricular function in patients undergoing abdominal aortic surgery.

In an open study of 26 patients undergoing abdominal aortic surgery, the effects of rocuronium 0.6 mg kg-1 (eight patients) and 0.9 mg kg-1 (nine patients) were compared with those of pancuronium 0.085 mg kg-1 (eight patients) on haemodynamic parameters and transoesophageal echocardiography. The anaesthetic technique was based on a benzodiazepine and low dose fentanyl (6 micrograms kg-1). Pancuronium was associated with a significant increase in mean arterial pressure, end-diastolic area and heart rate, none of which were seen after rocuronium at either dose level.

Androstanols↗
PubMed1993

[Value of thallium-dipyridamole myocardial scintigraphy in coronary patients in non cardiac surgery].

Cardiac assessment is of particular importance in patients with documented or suspected coronary artery disease (CAD) as well as in all those patients undergoing vascular surgery. Use of dipyridamole thallium scintigraphy (DTS) in this population could help to detect significant coronary artery narrowing, together with the location and quantification of the areas of myocardium in jeopardy. Such information might lead to changing the surgical procedure, or to starting other treatment, such as coronary angioplasty or bypass graft surgery, thereby diminishing the morbidity and mortality associated with surgery in these high-risk patients. The ability of DTS to predict acute postoperative ischaemic events has been suggested by several studies. Various shortcomings of DTS used as a preoperative screening test have been pointed out in some recent papers. Therefore it is concluded that: 1) DTS should not be used as a routine preoperative test in vascular surgical patients. DTS is not accurate enough when used in patients without any clinical findings suggestive of CAD, 2) DTS may prove more useful in stratifying patients with an intermediate probability of developing cardiac complications. In such patients, the test will not provide a linear "all or nothing" result, but, when taken together with the clinical findings and the nature of the surgical procedure, a complex stratification, 3) Because of progress in the perioperative management of high-risk patients, positive findings on preoperative DTS may not correlate perfectly with perioperative cardiac events, 4) As several factors influence thallium uptake after dipyridamole, DTS does not have a perfect specificity, thus leading to order an excessive number of coronary angiographies. Some patients will be seen as having a false-positive DTS, 5) Preoperative screening DTS leads to cardiac catheterization and hence to revascularisation, independently of symtomatology. Further studies must be undertaken to determine whether this approach will improve short and long term patient survival.

Coronary Disease↗