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D Thys

Publications and source records attributed to D Thys.

6 recordsLinked to original sources
PubMed1988

Control of perioperative hypertension during coronary artery surgery. A randomised double-blind study comparing isosorbide dinitrate and nitroglycerin.

A reduction in the causes of myocardial ischaemia remains of prime importance during coronary artery surgery. Hypertension with the ensuing increase in myocardial oxygen demand is a major factor in the aetiology of perioperative myocardial ischaemia. Nitroglycerin (NTG) has long been used beneficially to reduce myocardial oxygen demand by its effects on the systemic and peripheral vascular resistances. An alternative nitrate, isosorbide dinitrate (ISDN) is now available as an intravenous preparation, and may offer technical advantages, both due to its stability in solution and also its longer in vivo half-life. We designed and carried out a multi-centre study to compare and evaluate the efficacy of ISDN and NTG in the management of perioperative hypertension in 85 patients undergoing elective coronary artery surgery. A total of 288 events in which the systolic blood pressure (SBP) exceeded a predetermined trigger value were observed. ISDN was successful in treating hypertension in 63% of the events, whereas NTG had an 83% success. The SBP was significantly lowered after treatment with either ISDN, 155 mmHg to 138 mmHg, or NTG, 160 mmHg to 130 mmHg. The mean successful dose rate for ISDN was 6.5 micrograms kg-1 min-1, whereas for NTG this was 3.8 micrograms kg-1 min-1. In the ISDN group less events took place possibly due to the longer duration of this drug. In many previous studies NTG has been found to be effective in controlling hypertension; ISDN offers and alternative approach in reducing hypertension.

Coronary Artery Bypass↗
PubMed1986

Validation of quantitative intraoperative transesophageal echocardiography.

Transesophageal echocardiography (TEE) is a new monitoring technique that images the heart and provides information on regional wall motion and left ventricular filling. However, despite its potential for inaccuracy due to its retrocardiac position and angulation, TEE has not been validated by another imaging technique. Using direct on-heart echocardiography (OHE) as a standard, the authors evaluated the ability of TEE to measure accurately left ventricular end-diastolic area (EDa), end-systolic area (ESa), and ejection fraction area (EFa). Ten patients with coronary artery disease without evidence of valvular dysfunction undergoing myocardial revascularization were studied. A Diasonics 3.5 MHz two-dimensional TEE probe was introduced into each patient's esophagus and positioned to obtain a view equivalent to the parasternal short-axis projection. A similar view was obtained by OHE using a sterilely prepared 3 MHz ATL probe placed on either the pericardium or epicardium. In each patient, immediately prior to and after pericardiotomy, both transesophageal and on-heart short-axis views at the level of the papillary muscles were obtained. Using a dedicated Diasonics computer echoanalyzer, EDa and ESa from four consecutive cardiac cycles were outlined with a light pen and averaged. EFa was calculated by the formula EFa = (EDa - ESa)/EDa. Seventeen comparable transesophageal and on-heart echocardiograms were obtained. ESa by TEE correlated well with ESa by OHE (15.13 +/- 9.62 cm2 vs. 14.92 +/- 10.53 cm2; r = 0.94). Similar results were obtained for EDa (27.75 +/- 9.88 cm2 vs. 30.40 +/- 13.99 cm2; r = 0.88) and EFa (0.49 +/- 0.17 vs. 0.54 +/- 0.13; r = 0.92). filling and ejection.

Coronary Disease↗