A New Pneumatic Pump for Extracorporeal Circulation: TPP (True Pulsatile Pump). Experimental and First Clinical Results

A pulsatile, membrane type pump, TPP, was developed for use in routine cardiac surgery. The artificial ventricle consists of a polycarbonate housing with an inlet and outlet polyurethane tricuspid valve. The membrane is actuated hydraulically. For pre-clinical studies, we designed a study in sheep. After a pump run of 6 hours the animals were allowed to recover and sacrificed after 72 hours. All clinical parameters returned to normal values (p>0.05 vs. control values). During pump run we found elevated free plasma hemoglobine. However, these values returned to normal until the end of the observation period. Thereafter, the device was used in ten routine cardiac surgery procedures. All patients survived the procedure and were discharged from hospital. The postoperative course of lab parameters (kidney, liver and blood count) was no different to routine cardiac surgical procedures. This pulsatile pump system can thus be safely employed in cardiac surgery.

Open clinical study of eye-drops containing tetrapeptides derived from substance P and insulin-like growth factor-1 for treatment of persistent corneal epithelial defects associated with neurotrophic keratopathy

BACKGROUND/AIMS

Loss of corneal sensation results in the development of persistent corneal epithelial defects. The combination of a substance P-derived peptide (FGLM-amide) and an insulin-like growth factor-1 (IGF-1)-derived peptide (SSSR) stimulates rabbit corneal epithelial migration in vitro and rabbit corneal epithelial wound closure in vivo. The clinical efficacy of eye-drops containing FGLM-amide and SSSR for the treatment of persistent corneal epithelial defects in individuals with neurotrophic keratopathy was examined in a prospective open study.

METHODS

Twenty-five consecutive patients (26 eyes) with persistent corneal epithelial defects associated with neurotrophic keratopathy were treated by administration of eye-drops containing FGLM-amide and SSSR. The course of epithelial healing was monitored by slit-lamp examination.

RESULTS

Epithelial defects resurfaced completely in 19 of the 26 eyes (73%) within 4 weeks after treatment initiation. Complete resurfacing of epithelial defects was apparent in 18 of 22 (82%) or in one of four (25%) eyes without or with limbal stem cell deficiency, respectively. No adverse effects of treatment were observed in any subject.

CONCLUSION

Eye-drops containing FGLM-amide and SSSR induced the rapid resurfacing of persistent epithelial defects in stem cell-positive individuals with neurotrophic keratopathy.

[Aprotinin reduces bleeding during off-pump coronary artery bypass grafting in a patient on ticlopidine; report of a case]

A 65-year-old man was admitted to a local hospital with symptoms of unstable angina pectoris. He was administered ticlopidine before drug eluting stent (DES) stenting for 2 weeks. Coronary angiography showed 3 vessel diseases. He was then admitted to our hospital due to a sudden onset of unstable angina following shock during the percutaneous coronary intervention (PCI) procedure, emergency off-pump coronary artery bypass grafting (OPCAB) was thus performed. He received aprotinin 5 hundred thousand KIU just at the start of surgery and 5 hundred thousand KIU after undergoing anastomosis of the coronary artery. Postoperatively, only some minor bleeding was observed. Aprotinin reduces bleeding, the transfusion requirements of packed red blood cells, platelets, and the total blood units in patients on ticlopidine who undergo emergency OPCAB.

[Posterior ventricular septal perforation successfully repaired through right ventricular approach]

A 65-year-old man underwent a successful repair of a posterior ventricular septal perforation (VSP) 9 days after suffering an acute inferior myocardial infarction. After hospitalization, his hemodynamic condition gradually worsened, in spite of administering intensive medical therapy. Emergent operation was performed on the 4th day after onset. An equine pericardial patch was sutured around the VSP through the right ventricular side of the septum using the double-patch repair method and the right ventricular wall was closed as using the standard extracorporeal perfusion technique. The dimensions of the VSP measured 5 mm in diameter. Transesophageal echocardiography was performed on the 14th postoperative day. Cardiac catheter examination was done on the 18th postoperative day. No residual shunt was recognized and cardiac function was good. He was discharged on the 20th postoperative day. The occurrence of a posterior VSP is comparatively rare, and repair of VSP is difficult to perform during an acute period. Therefore, the operative results of VSP cases remain poor.

Promotion of corneal epithelial wound healing in diabetic rats by the combination of a substance P-derived peptide (FGLM-NH2) and insulin-like growth factor-1

AIMS/HYPOTHESIS

The healing of corneal epithelial wounds is often delayed in individuals with diabetes. The effect of the combination of a substance P-derived tetrapeptide (phenylalanine-glycine-leucine-methionine amide, or FGLM-NH(2)) and insulin-like growth factor-1 (IGF-1) on corneal epithelial wound healing was investigated in rats with streptozotocin-induced diabetes.

METHODS

The corneal epithelium of diabetic and non-diabetic rats was removed, and the animals were treated by the application of eye drops containing FGLM-NH(2) and IGF-1, or vehicle alone as a control, six times a day for 3 days. The area of the corneal epithelial wound was measured at various times up to 72 h after removal of the corneal epithelium.

RESULTS

The rate of corneal epithelial wound healing was slower in diabetic rats treated with vehicle than in non-diabetic rats. However, the rate of wound closure in diabetic rats treated with FGLM-NH(2) and IGF-1 was markedly increased compared with that in diabetic rats treated with vehicle. The wound healing process seemed similar in normal rats and in diabetic rats treated with FGLM-NH(2) and IGF-1.

CONCLUSION/INTERPRETATION

The combination of FGLM-NH(2) and IGF-1 promotes corneal epithelial wound healing in diabetic rats, suggesting that such a treatment might prove effective in humans with diabetic keratopathy.

Abnormal light scattering detected by confocal biomicroscopy at the corneal epithelial basement membrane of subjects with type II diabetes

AIMS/HYPOTHESIS

Abnormalities of the basement membrane are thought to contribute to the complications of diabetes. The suitability of the cornea for detecting such abnormalities was assessed by determining its light-scattering index, a quantitative measure of tissue reflectivity in the basement membrane zone, with a confocal biomicroscope.

METHODS

The light-scattering index was measured in 65 subjects with Type II (non-insulin-dependent) diabetes mellitus and 18 control subjects and was evaluated for its possible relation to the stage of diabetic retinopathy. Diabetic retinopathy was staged by ophthalmoscopic examination as non-diabetic (NDR), simple (SDR), preproliferative (PPDR), or proliferative (PDR).

RESULTS

Examination of the cornea layer-by-layer with a confocal biomicroscope did not show any marked differences in morphology between diabetic and control subjects. The LSI (mean +/- SD) was 0.81 +/- 0.13, 0.87 +/- 0.09, 0.90 +/- 0.09, 0.90 +/- 0.13, and 1.02 +/- 0.25 in control subjects and in diabetic subjects with NDR, SDR, PPDR, or PDR, respectively; the light-scattering index of diabetic subjects with PDR was significantly greater than that of the control subjects (p = 0.001). An LSI greater than 1.0 was detected in 5.6, 6.3, 15.0, 15.4, and 50.0% of control subjects and of patients with NDR, SDR, PPDR, or PDR, respectively; the percentage of subjects with an LSI greater than 1.0 was significantly increased in diabetic patients with PDR than for control subjects.

CONCLUSION/INTERPRETATION

These results suggest that the LSI increases with the stage of diabetic retinopathy, and that measurement of corneal light scattering could provide an index of basement membrane abnormality in people with diabetes.

[Retrograde continuous cold blood cardioplegia for combined aortic valve replacement and coronary artery bypass grafting]

Efficacy of retrograde continuous cold blood cardioplegia (RCBC) during aortic valve replacement combined with coronary bypass grafting was studied. Forty patients underwent elective aortic valve replacement, either combined with coronary bypass grafting (7 patients: group I), or isolated (33 patients: group II) using RCBC between 1996 and 1999 were analyzed retrospectively. Aortic cross clamp time was significantly prolonged in group I (150 +/- 33 min) compared to group II (109 +/- 32 min). The postoperative peak creatine kinase-MB levels were similar in both groups (73.3 +/- 23.9 versus 97.6 +/- 88.7 ng/ml). The doses of dopamine and dobutamine administered during 24 hours after surgery did not differ between the two groups (7.5 +/- 3.9 versus 6.5 +/- 5.5 mg/kg). The early (< 30-day) mortality was 0 in group I, and 3.0% in group II. These results suggest that RCBC is a safe method of myocardial protection in patients undergoing aortic valve replacement combined with coronary artery bypass grafting.

[The management of aortic root replacement using the Top-Hat/Gelweave composite graft]

Composite graft replacement of the aortic root has become a routine procedure for annuloaortic ectasia (AAE) and aortic valve insufficiency (AR) with aortic dissection and the results have improved. We treated six cases of aortic root reconstruction using the Carrel patch method in 1998. The Top-Hat/Gelweave Composite graft fit together well and the procedure is technically similar to standard valve replacement. Upon measuring the valve size a Gelweave graft 1 mm larger than the valve size should be selected. There were no incidence of hemorrhage or postoperative hemolysis. Further long-term follow-up is necessary.

[The management of infectious mediastinitis after the open heart surgery]

Between October of 1992 and September of 1998, we performed 604 open heart operations. Among them, 12 cases (1.9%) were complicated with postoperative infectious mediastinitis. Five patients (Group A) were treated by conservative therapy which consists of open drainage and intermittent closed irrigation with dilute povidone iodine solution. Seven patients (Group B) were treated surgically in addition to the above-mentioned conservative treatment. Among those patients, one patient developed fatal complication. We have realized that mental care of the patients was also very important when long term hospitalization was necessitated. The hyperbaric oxygen therapy seemed to be also effective for postoperative mediastinitis caused by MRSA.

Direct observation of corneal nerve fibres in neurotrophic keratopathy by confocal biomicroscopy

Non-invasive confocal biomicroscopy revealed regeneration of corneal nerve fibres coincident with corneal epithelial healing in a patient with neurotrophic keratopathy.

A new pneumatic pump for extracorporeal circulation: TPP (true pulsatile pump). Experimental and first clinical results

A pulsatile, membrane type pump, TPP, was developed for use in routine cardiac surgery. The artificial ventricle consists of a polycarbonate housing with an inlet and outlet polyurethane tricuspid valve. The membrane is actuated hydraulically. For pre-clinical studies, we designed a study in sheep. After a pump run of 6 hours the animals were allowed to recover and sacrificed after 72 hours. All clinical parameters returned to normal values (p > 0.05 vs. control values). During pump run we found elevated free plasma hemoglobine. However, these values returned to normal until the end of the observation period. Thereafter, the device was used in ten routine cardiac surgery procedures. All patients survived the procedure and were discharged from hospital. The postoperative course of lab parameters (kidney, liver and blood count) was no different to routine cardiac surgical procedures. This pulsatile pump system can thus be safely employed in cardiac surgery.

R56865, a Na(+)- and Ca(2+)-overload inhibitor, reduces myocardial ischemia-reperfusion injury in blood-perfused rabbit hearts

The cardioprotective effects of R56865 were studied in isolated rabbit hearts, blood-perfused with a support rabbit system. The effect on ischemic injury was evaluated by comparing myocardial contracture and contents of ATP catabolites and of lactate during 60 min of normothermic ischemia in untreated hearts (group I) and in hearts treated with 0.63 mg/kg of R56865 starting 20 min before ischemia (group II; n = 5 in each group). R56865 delayed the onset, and decreased the extent of ischemic contracture, but had no effect on the myocardial content of ATP, of its catabolites of lactate. The effect on reperfusion injury was studied by monitoring left ventricular function during 80-min reperfusion after the 60-min ischemia in three groups (n = 6 in each): an untreated group (group I) and two groups treated with R56865 given either before (group II) or after ischemia (group III). Ultrastructural changes and cellular calcium distribution after reperfusion were also studied. R56865 improved the recovery of function and prevented contracture during reperfusion. Left ventricular end-diastolic pressure was 13.2 +/- 2.8 mmHg in group II and 31.3 +/- 8.1 mmHg in group III vs 45.0 +/- 2.6 mmHg in group I (P < 0.0001 for II vs I; P > 0.05 for III vs I). Left ventricular developed pressure, maximum dP/dt and minimum dP/dt recovered to 71.0 +/- 5.4%, 98.9 +/- 6.1%, 85.3 +/- 4.8% of baseline values, respectively, in group II, to 64.5 +/- 3.0% (P > 0.05), 76.8 +/- 3.0%, 70.2 +/- 4.0% in group III, vs 52.0 +/- 6.5%, 58.9 +/- 6.9% and 53.6 +/- 5.8% in untreated hearts (P < 0.05 for II or III vs I). Coronary flow was 24.5 +/- 2.2 ml/min and 19.8 +/- 1.8 ml/min in groups II and III vs 14.8 +/- 0.7 ml/min (P < 0.05) in the untreated group. On histology the myocardium in hearts treated either before or after ischemia was well protected and calcium distribution was almost normal after reperfusion, while in untreated hearts, most of the myocardium displayed irreversible damage accompanied by massive intracellular calcium accumulation. We conclude that R56865 could attenuate Ca(2+)-overload, thereby reducing myocardial ischemia-reperfusion injury after an extended period of ischemia.

Early and late results with combined mitral and aortic valve replacement

From February 1977 to January 1993, a total of 52 patients have undergone combined mitral and aortic valve replacement (MAVR) at the Fukuoka University Hospital. The ages at operation ranged from 35 to 72 years (mean, 55.3 years) for 16 males and 36 females. Twenty-five patients received two bioprosthetic valves (group BB); 6 received a combination of bioprosthetic valve and mechanical valve (group BM); and 21 received two mechanical valves (group MM). The previous intra-cardiac operations were performed on 24 patients (46.2%). The purpose of this study was to learn about the long-term clinical results of MAVR and to analyze the difference among three groups. Seven patients died within 30 days of operation or during initial hospitalization (early mortality: 13.5%). Two patients died at late period, 5.8 years and 6.9 years after operation, respectively (linearized occurrence rate: 0.9%/pt-yr). Patient survival rate including operative death was 82.9% +/- 5.7% at 5 years and 79.0% +/- 6.7% at 8 years in the total number of patients. Thromboembolism occurred in 2 patients in group MM (0.9%/pt-yr). Anticoagulant-related hemorrhage occurred only in 1 patient (0.4%/pt-yr in overall), in whom two bioprosthetic valves were implanted (group BB), in spite of being in good control with anticoagulants. No infective endocarditis was encountered in any patients during any of the periods. Reoperations were performed in 7 patients (3%/pt-yr in overall), 5 in group BB and 2 in group MM. Percentage freedom from reoperation was 86.4% +/- 5.9% at 5 years and 78.2% +/- 7.7% at 8 years in all. There was no difference among the three groups. Percentage freedom from overall morbidity and mortality was 74.5% +/- 6.9% at 5 years in all. Group MM showed higher morbidity and mortality at 8 years than other groups, but there were no significance (MM: 52.4% +/- 17.6%, BB: 76.5% +/- 9.5%, BM: 83.3% +/- 15.2%). We conclude that there were no significant differences in long-term results of NAVR which consisted of the following combinations of prostheses such as BB, BM, and MM. Redoing MAVR with New York Heart Association functional class IV and emergency cases were considered as in-hospital risk factors.

[Treatment of postoperative mediastinitis using an omental pedicle flap]

Four patients with postoperative mediastinitis who were treated by omentopexy at the Fukuoka University Hospital between 1989 and 1990. Three of the 4 patients healed successfully, another one died of multiple organ failure 83 days after surgery. All patients were received coronary artery bypass surgery harvesting a left internal thoracic artery for ischemic heart disease. Three patients had diabetes mellitus, one patient had renal failure preoperatively. Recognition of mediastinitis was made by sternal wound purulent discharge and sternal dehiscence. Culture of the discharge fluid yielded methicillin-resistant Staphylococcus aureus in three, and Enterococcus cloacae in one. Irrigation with popidone-iodine or blonopol were ineffective. Thus, the wound was treated with debridement and omentopexy with an omental pedicle flap, respectively. Postoperative course after omentopexy were excellent, had no complications. We conclude that the omentopexy is useful in the treatment of postoperative refractory anterior mediastinitis.

[Preservation of the isolated canine heart for 24 hours by retrograde gaseous oxygen insufflation]

Isolated canine hearts were used to evaluate retrograde gaseous oxygen insufflation into the heart at 4 degrees C compared with simple storage as a method of preservation for 24 hours. The hearts were reperfused with ex vivo apparatus and assessed by left ventricular functional recovery and myocardial energy metabolism. Gas insufflated hearts showed significantly better maintenance of creatine phosphate and adenosine triphosphate content, lower lactate accumulation, and better functional recovery compared with simple storage. However, at the early period of reperfusion, coronary vascular resistance rose significantly in gas-insufflated hearts. Gas-insufflation storage of isolated hearts is capable of maintaining aerobic metabolism, and may be suitable for long distant heart procurement. However, this method may cause gas embolism or any vascular damage which impair the beneficial effects.

[En-block bilateral lung transplantation: experiments in dogs]

En-block bilateral lung transplantation was performed in dogs according to methods introduced by Dark et al and Patterson et al. Under the extra-corporeal bypass the donor's trachea, atrium and pulmonary artery trunk were anastomosed to those of recipient, respectively. Five dogs receiving bilateral lung transplantation died after a short period survival because of hemodynamic insufficiency postoperatively. Although the aim of the experiment in this series was the follow-up trial of double lung transplantation, in consequence the poor prognoses were gained, we believe the long-term survival may be possible by the device skill in the technique.