Biomedical subjects

D De Canniere

Publications and source records attributed to D De Canniere.

7 recordsLinked to original sources

PubMed2002

Conversion from ministernotomy to full sternotomy in aortic valve replacement.

Conversion (C) from ministernotomy (M.S.) to full sternotomy was necessary in 5% of the cases in a series of 100 patients consecutively operated for Aortic Valve Replacement (A.V.R.) Analysis of the demographics and surgical techniques indicate older age, aortic fragility, diffuse coronary disease, chronic renal failure and left vent insertion as contributing factors. Despite increased operative blood losses, extra-corporeal circulation (E.C.C.) times, intensive care unit (I.C.U.) stay and hospital stay, no mortality was observed in the conversion group, as compared to 4.2% mortality in the total ministernotomy (MS) population. Preoperative patients selection, avoidance of technical pitfalls, and knowledge of alternative surgical measures are suggested to further decrease the incidence of conversions.

Aged↗

PubMed1998

Effects of pulmonary embolism on pulmonary vascular impedance in dogs and minipigs.

Pigs have been reported to present with a stronger pulmonary vascular reactivity than many other species, including dogs. We investigated the pulmonary vascular impedance response to autologous blood clot embolic pulmonary hypertension in anesthetized and ventilated minipigs (n = 6) and dogs (n = 6). Before embolization, minipigs, compared with dogs, presented with higher mean pulmonary arterial pressure (Ppa; by an average of 9 mmHg), a steeper slope of Ppa-flow (Q) relationships, and higher 0-Hz impedance (Z0) and first-harmonic impedance (Z1), without significant differences in characteristic impedance (Zc), and a lower ratio of pulsatile hydraulic power to total hydraulic power. Embolic pulmonary hypertension (mean Ppa: 40-55 mmHg) was associated with increased Z0 and Z1 in both species, but the minipigs had a steeper slope of Ppa/Q plots and an increased Zc. At identical Q and Ppa, minipigs still presented with higher Z1 and Zc and a lower ratio of pulsatile hydraulic power to total hydraulic power. The energy transmission ratio, defined as the hydraulic power in the measured waves divided by the hydraulic power in the forward waves, was better preserved after embolism in minipigs. No differences in wave reflection indexes were found before and after embolism. We conclude that minipigs, compared with dogs, present with a higher pulmonary vascular resistance and reactivity and adapt to embolic pulmonary hypertension by an increased Zc without earlier wave reflection. These differences allow for a reduced pulsatile component of hydraulic power and, therefore, a better energy transfer from the right ventricle to the pulmonary circulation.

Animals↗

PubMed1997

Left ventricular outflow tract obstruction after mitral valve replacement.

We describe a patient with left ventricular outflow tract obstruction after mitral valve replacement preserving the anterior subvalvular apparatus. Postoperative transesophageal echocardiography demonstrated systolic narrowing of the left ventricular outflow tract by a bulging septum and systolic anterior motion of the preserved anterior mitral leaflet. Septal myectomy and transaortic mitral apparatus resection enabled us to relieve the left ventricular outflow tract obstruction. This suggests that septal hypertrophy might be a relative contraindication to the preservation of the anterior mitral subvalvular apparatus in mitral replacement.

Aged↗

PubMed1996

Severe syncope due to the application of a pacemaker telemetry wand.

We report a case of a transient defective anodal contact between pacemaker ground plate and patient's tissues (the so-called dry pocket). During unipolar-DDD pacing, mild compression of the pocket with the telemetry head caused a severe syncope, due to asystole and secondary to complete loss of ventricular capture. Normal pacemaker function resumed with bipolar pacing configuration.

Equipment Failure↗

PubMed1995

Pulmonary vascular impedance response to hypoxia in dogs and minipigs: effects of inhaled nitric oxide.

The pig has been reported to present with a stronger hypoxic pulmonary vasoconstriction (HPV) than many other species, including dogs. We investigated [pulmonary arterial pressure (Ppa)-pulmonary arterial occluded pressure (Ppao)] vs. pulmonary blood flow (Q) relationships and pulmonary vascular impedance (PVZ) spectra in nine minipigs and nine weight-matched dogs. The animals were anesthetized and ventilated in hyperoxia [inspired O2 fraction 0.4] or hypoxia (inspired O2 fraction 0.12). PVZ was computed from the Fourier series for Ppa and Q. In hyperoxia, the pigs had a higher Ppa (26 +/- 1 vs. 16 +/- 1 mmHg), a higher first-harmonic impedance (Z1), and a more negative low-frequency phase angle but no different characteristic impedance (Zc) compared with the dogs at the same Q. Hypoxia in the dogs increased (Ppa-Ppao) at all levels of Q studied by an average of 2 mmHg but did not affect Z1 or Zc. Hypoxia in the pigs increased (Ppa-Ppao) at all levels of Q by an average of 13 mmHg and increased Z1 and Zc. Inhaled NO (150 ppm) reversed the hypoxia-induced changes in (Ppa-Ppao)/Q plots and PVZ in the dogs and pigs. However, differences in (Ppa-Ppao)/Q plots and PVZ between the dogs and pigs in hyperoxia and hypoxia were not affected by inhaled NO. We conclude 1) that minipigs present with an elevated pulmonary vascular resistance and impedance in hypoxia more than in hyperoxia and 2) that baseline differences in pulmonary hemodynamics between dogs and minipigs are structural rather than functional.

Administration, Inhalation↗

PubMed1994

Effects of a chronic aortopulmonary shunt on pulmonary hemodynamics in piglets.

Systemic-to-pulmonary shunting in growing pigs has been proposed as an experimental model of high-flow pulmonary hypertension associated with congenital heart defects. We investigated multipoint pulmonary arterial pressure (Ppa) vs. cardiac output (Q) plots and pulmonary vascular impedance spectra in 13 piglets aged approximately 4 mo and ventilated alternatively in hyperoxia (inspired O2 fraction 0.4) and in hypoxia (inspired O2 fraction 0.12). The measurements were done 8 wk after either an anastomosis between the thoracic aorta and the pulmonary trunk (n = 7 piglets) or a sham operation (n = 6). Cardiac output was altered by a manipulation of venous return. In the sham-operated piglets, hypoxia increased Ppa by an average of 12 mmHg over the entire range of Q studied, from 60 to 120 ml/kg, and increased both 0 Hz (Z0) and characteristic (Zc) pulmonary vascular impedance. In the shunted piglets compared with the sham-operated piglets in hyperoxia, Ppa was increased by an average of 5-6 mmHg at all levels of Q studied, from 60 to 120 ml/kg (P < 0.01), and Zc was also increased (P < 0.01), whereas Z0 was unchanged. In the shunted piglets, hypoxia increased Ppa at all levels of Q studied only to an average of 3 mmHg, and neither Z0 nor Zc was altered by hypoxia. We conclude that an aortopulmonary shunt of 2-mo duration in growing pigs increases both pulmonary vascular resistance and impedance and is associated with a blunting of pulmonary vascular reactivity to hypoxia.

Animals↗

PubMed1992

Stimulus-response curves for hypoxic pulmonary vasoconstriction in piglets.

OBJECTIVE: The aim was to characterise stimulus-response curves for hypoxic pulmonary vasoconstriction and to observe the effects of drugs reputed to enhance it: aspirin (a cyclo-oxygenase inhibitor), and doxapram (a peripheral chemoreceptor agonist). METHODS: Mean pulmonary artery pressure (Ppa) versus fraction of inspired O2 (FIO2) relationships were studied in 18 intact anaesthetised piglets, before and after the intravenous administration, in random order, of either physiological saline, 1 g aspirin, or 20 mg.kg-1 doxapram. Cardiac output (Q) was kept constant, to avoid passive Q dependent changes in Ppa. RESULTS: A progressive decrease in FIO2 from 100% to 12% was associated with an average increase in Ppa from 19 to 38 mm Hg (p < 0.001). When FIO2 was further decreased to 8%, Ppa decreased to 32 mm Hg (p < 0.01). This stimulus-response curve was unaffected by saline, but displaced in a non-PO2-dependent manner to higher Ppa by doxapram and by aspirin. CONCLUSIONS: The pulmonary vascular response to inspiratory hypoxia in intact anaesthetised piglets is biphasic, with a maximum at an FIO2 of 12%. Neither aspirin nor doxapram affect the shape of this stimulus-response curve, and in particular do not prevent low FIO2 associated inhibition of hypoxic pulmonary vasoconstriction.

Animals↗