Repair of aortic leaflet prolapse: The "sliding leaflet technique"

Valve-preserving aortic replacement has become an accepted therapeutic option for aortic dilatation with normal valve leaflets. The presence of a leaflet prolapse often induces the choice of a composite graft repair. In these cases, however, the repair of a leaflet prolapse is possible and represents a valuable alternative to a prosthetic valve. The conventional techniques of repair of a cusp prolapse are designed to restore coaptation through a reduction of free margin length. The sliding leaflet technique is an alternative procedure conceived to repair the prolapsed valve cusp by remodeling both the free margin and the annular insertion. \ua9 2005 by The Society of Thoracic Surgeons

Mechanisms of desflurane-induced preconditioning in isolated human right atria in vitro

BACKGROUND: The authors examined the role of adenosine triphosphate-sensitive potassium (K(ATP)) channels, adenosine A1 receptor, and alpha and beta adrenoceptors in desflurane-induced preconditioning in human myocardium, in vitro. METHODS: The authors recorded isometric contraction of human right atrial trabeculae suspended in oxygenated Tyrode's solution (34 degrees C; stimulation frequency, 1 Hz). Before a 30-min anoxic period, 3, 6, and 9% desflurane was administered during 15 min. Desflurane, 6%, was also administered in the presence of 10 microm glibenclamide, a K(ATP) channels antagonist; 10 microm HMR 1098, a sarcolemmal K(ATP) channel antagonist; 800 microm 5-hydroxy-decanoate (5-HD), a mitochondrial K(ATP) channel antagonist; 1 microm phentolamine, an alpha-adrenoceptor antagonist; 1 microm propranolol, a beta-adrenoceptor antagonist; and 100 nm 8-cyclopentyl-1,3-dipropylxanthine (DPX), the adenosine A1 receptor antagonist. Developed force at the end of a 60-min reoxygenation period was compared (mean +/- SD). RESULTS: Desflurane at 3% (95 +/- 13% of baseline), 6% (86 +/- 6% of baseline), and 9% (82 +/- 6% of baseline) enhanced the recovery of force after 60 min of reoxygenation as compared with the control group (50 +/- 11% of baseline). Glibenclamide (60 +/- 12% of baseline), 5-HD (57 +/- 21% of baseline), DPX (63 +/- 19% of baseline), phentolamine (56 +/- 20% of baseline), and propranolol (63 +/- 13% of baseline) abolished desflurane-induced preconditioning. In contrast, HMR 1098 (85 +/- 12% of baseline) did not modify desflurane-induced preconditioning. CONCLUSIONS: In vitro, desflurane preconditions human myocardium against simulated ischemia through activation of mitochondrial K(ATP) channels, adenosine A1 receptor, and alpha and beta adrenoceptors

Etomidate has no effect on hypoxia reoxygenation and hypoxic preconditioning in isolated human right atrial myocardium

BACKGROUND: We examined the effects of etomidate on recovery of contractile function after hypoxia reoxygenation and hypoxic preconditioning in vitro using isolated human myocardium. METHODS: Human right atrial myocardium were obtained at the time of cardiac surgery from 38 adults patients. We recorded isometric force of contraction (FoC) of atrial trabeculae suspended in an oxygenated Tyrode's solution (34 degrees C, stimulation frequency 1 Hz). In all groups, a 30-min hypoxic period was followed by 60 min of reoxygenation (HR). In separate groups, muscles were exposed to etomidate (10(-7), 10(-6), 10(-5) M) 10 min before and throughout the HR periods. Hypoxic preconditioning was induced by 4-min hypoxia followed by 7-min reoxygenation applied before HR periods. Etomidate 10(-5) M was administered before, throughout, and after the hypoxic preconditioning stimulus. Recovery of FoC (expressed as % of baseline value) at the end of HR was compared among groups. RESULTS: Compared with the control group (FoC: 52%+/-10%), etomidate 10(-7) M (FoC: 57%+/-9%; P=0.24), 10(-6) M (FoC: 61%+/-11%; P=0.10), and 10(-5) M (FoC: 54%+/-9%; P=0.29) did not modify the recovery of FoC after HR. Hypoxic preconditioning-induced increase in the recovery of FoC (87%+/-5%; P<0.001 vs control group) was not modified in the presence of etomidate 10(-5) M (FoC: 86%+/-7%; P=0.74 vs hypoxic preconditioning group). CONCLUSIONS: Etomidate did not modify the in vitro FoC of human myocardium exposed to HR. Furthermore, etomidate did not modify the protective effect of hypoxic preconditioning

Reactive oxygen species mediate sevoflurane- and desflurane-induced preconditioning in isolated human right atria in vitro

BACKGROUND: We examined the role of reactive oxygen species (ROS) in sevoflurane- and desflurane-induced preconditioning on isolated human right atrial myocardium. METHODS: We recorded isometric contraction of human right atrial trabeculae suspended in an oxygenated Tyrode's solution (34 degrees C, stimulation frequency 1 Hz). In all groups, a 30-min hypoxic period was followed by 60 min of reoxygenation. Ten minutes before hypoxia reoxygenation, muscles were exposed to 5 min of sevoflurane 2% or desflurane 6%. In separate groups, the sevoflurane 2% (Sevo + N-(2-mercaptopropionyl)-glycine [MPG]) or desflurane 6% (Des + MPG) was administered in the presence of 0.1 mM MPG, a ROS scavenger. The effect of 0.1 mM MPG alone was tested. Recovery of force after a 60-min reoxygenation period was compared between groups (mean +/- sd). RESULTS: Preconditioning with sevoflurane 2% (85% +/- 4% of baseline) or desflurane 6% (86% +/- 7% of baseline) enhanced the recovery of the force of myocardial contraction after 60 min reoxygenation compared with the control group (53% +/- 11% of baseline, P < 0.001). This effect was abolished in the presence of MPG (56% +/- 12% of baseline for Sevo + MPG, 48% +/- 13% of baseline for Des + MPG). The effect of MPG alone on the recovery of force was not different from the control group (57% +/- 7% of baseline versus 53% +/- 11%; P = NS). CONCLUSIONS: In vitro, sevoflurane and desflurane preconditioned human myocardium against hypoxia through a ROS-dependent mechanism

Less invasive radial artery harvesting: Two years' experience

Background. For coronary surgery we often use the radial artery (RA) instead of the saphenous vein, trying to exploit the advantages offered by this conduit. To eliminate the problems regarding alteration of upper-extremity function after RA procurement related to the standard conventional harvesting technique, we started using the less invasive harvesting technique with surprisingly good preliminary results. To compare the outcomes of open versus less invasive harvesting procedures, a prospective, nonrandomized study was developed by 2 centers. Methods. From January 2001 to March 2003, there were 87 consecutive patients in the less invasive radial artery harvesting (LIRAH) group and 90 patients in the conventional radial artery harvesting (CRAH) group. Patient characteristics and demographics were similar in the groups. Data collection was made to evaluate possible benefits of the LIRAH technique in terms of fewer forearm and hand complications, better aesthetics, and improved patient satisfaction. Results. Between January 11, 2001, and March 30, 2003, 177 patients underwent either primary or redo coronary artery revascularizations with, procurement of the RA for use as a conduit with the less invasive harvesting technique. The mean follow-up was 2 months. Four patients died, and overall mortality was 2.26%. One hundred seventy-three patients were successfully examined during the first postoperative control, 85 in the LIRAH group and 88 patients in the CRAH group. Objective and subjective data were collected from the consultant. The overall average age was 60.5 years (range, 40-77 years). In the LIRAH group, the mean overall incision length (when 2 incisions were necessary, both, incision lengths were measured) was 5.6 cm (range, 4-10 cm), and the mean vessel length was 16 cm (range, 10-19 cm). Eighteen patients (20.6%) necessitated double incision. Mean harvesting time (from incision to skin closure) was 43.3 min (range, 25-70 min). Fourteen patients (16.4%) presented some kind of complication during the study. There were no cases with, acute ischemia, bleeding, or re-exploration. Seventy-five patients (88.2%) found the cosmetic result excellent. Ten patients (11.8%) found it good, and none considered it mediocre. In the CRAH group, the mean incision length was 20 cm (range, 18-22 cm), and the mean vessel length was 18 cm (range, 17-20 cm ). Mean harvesting time (from incision to skin closure) was 30.8 min (range, 14-45 min). Thirty-four patients (38.6%) presented some kind of complication during the study. Three patients (3.5%) found the cosmetic result excellent. Forty-three (48.8%) found it good, and 42 (47.7%) considered it mediocre. Conclusions. A potential of fewer neurological forearm postoperative complications, better aesthetics, and improved patient satisfaction can be achieved by the LIRAH technique. \ua9 2005 Forum Multimedia Publishing, LLC

Mechanisms of sevoflurane-induced myocardial preconditioning in isolated human right atria in vitro

BACKGROUND: The authors examined the role of adenosine triphosphate-sensitive potassium channels and adenosine A(1) receptors in sevoflurane-induced preconditioning on isolated human myocardium. METHODS: The authors recorded isometric contraction of human right atrial trabeculae suspended in oxygenated Tyrode's solution (34 degrees C; stimulation frequency, 1 Hz). In all groups, a 30-min hypoxic period was followed by 60 min of reoxygenation. Seven minutes before hypoxia reoxygenation, muscles were exposed to 4 min of hypoxia and 7 min of reoxygenation or 15 min of sevoflurane at concentrations of 1, 2, and 3%. In separate groups, sevoflurane 2% was administered in the presence of 10 microm HMR 1098, a sarcolemmal adenosine triphosphate-sensitive potassium channel antagonist; 800 microm 5-hydroxy-decanoate, a mitochondrial adenosine triphosphate-sensitive potassium channel antagonist; and 100 nm 8-cyclopentyl-1,3-dipropylxanthine, an adenosine A(1) receptor antagonist. Recovery of force at the end of the 60-min reoxygenation period was compared between groups (mean +/- SD). RESULTS: Hypoxic preconditioning (90 +/- 4% of baseline) and sevoflurane 1% (82 +/- 3% of baseline), 2% (92 +/- 5% of baseline), and 3% (85 +/- 7% of baseline) enhanced the recovery of force after 60 min of reoxygenation compared with the control groups (52 +/- 9% of baseline). This effect was abolished in the presence of 5-hydroxy-decanoate (55 +/- 14% of baseline) and 8-cyclopentyl-1,3-dipropylxanthine (58 +/- 16% of baseline) but was attenuated in the presence of HMR 1098 (73 +/- 10% of baseline). CONCLUSIONS: In vitro, sevoflurane preconditions human myocardium against hypoxia through activation of adenosine triphosphate-sensitive potassium channels and stimulation of adenosine A(1) receptors

Back from irreversibility: Extracorporeal life support for prolonged cardiac arrest

The survival of patients after prolonged cardiac arrest is still inadequate. Extracorporeal life support (ECLS) represents an alternative therapeutic method for patients who do not respond to conventional cardiopulmonary cerebral resuscitation. This technology is used to support the circulation of a patient with severe cardiac failure. Between June 1997 and January 2003, 40 ECLS procedures were performed in patients who presented with refractory cardiac arrest. During external cardiac massage, the patient was connected to an extracorporeal circuit by the insertion of an arterial and venous cannula through the femoral vessels. The extracorporeal circuit included a centrifugal pump and an oxygenator. Mean age was 42 \ub1 15 years; the average time of external cardiac massage was 105 \ub1 44 minutes. Once the circulation was restored, 22 patients were disconnected from the extracorporeal circulation because of brain death or multiorgan failure; after 24 hours, among the 18 survivors, 6 were weaned off the pump, 9 were bridged to a ventricular assist device, and 2 patients were directly bridged to cardiac transplantation. Eight patients are alive and without any sequelae at 18 month's follow-up. In prolonged cardiac arrest with failing conventional measures, rescue by extracorporeal support provides an ultimate therapeutic option with a good outcome in survivors. Our results encourage the wider application of ECLS for refractory cardiocirculatory arrest in selected patients. The high rate of neurologic death needs further improvements in the early phase of resuscitation maneuvers. \ua9 2005 by The Society of Thoracic Surgeons

The inotropic and lusitropic effects of ketamine in isolated human atrial myocardium: The effect of adrenoceptor blockade

We studied the direct myocardial effects of racemic ketamine, in the presence of \u3b1- and \u3b2-adrenoceptor blockade, on isolated human right atrial myocardium. Isometric force of contraction (FoC), its first derivative with time (+dF/dt), the contraction relaxation coupling parameter R2 = (+dF/dt) / (-dF/dt), and time to half relaxation (T1/2) were recorded before and after addition of 10-6, 10-5 and 10-4 M racemic ketamine alone and in the presence of \u3b1-adrenoceptor blockade (phentolamine 10-6 M) and \u3b2-adrenoceptor blockade (propranolol at 10-6 M). Ketamine had a moderate positive inotropic effect at 10-5 M (FoC, 104% \ub1 5% of baseline value; P = 0.03) and 10-4 M (FoC, 107% \ub1 11% of baseline value; P = 0.09). Racemic ketamine had a negative inotropic effect in the presence of propranolol (FoC, ketamine 10-6 M, 77% \ub1 11%; ketamine 10-5 M, 63% \ub1 16%; ketamine 10-4 M, 62% \ub1 17% of baseline; P < 0.001) but not phentolamine (FoC, ketamine at 10-6 M, 94% \ub1 6%; ketamine 10-5 M, 96% \ub1 5%; and ketamine 10-4 M, 98% \ub1 15% of baseline). Ketamine decreased T1/2 (ketamine 10-5 M, 94% \ub1 3% of baseline value; P < 0.001 and ketamine 10-4 M, 90% \ub1 9% of baseline value; P = 0.007) but did not modify R2. In human right atrial myocardium, racemic ketamine induced a moderate positive inotropic effect and hastened isometric relaxation. In the presence of \u3b2-adrenoceptor blockade it induced a direct negative inotropic effect