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At least 451 records · Page 25Linked to original sources
PubMed1979

[Partial mechanical cardiac replacement in experimental cardiogenic shock].

The importance to evaluate artificial ventricles for left heart assist under cardiogenic shock conditions is emphasized. The main cardiogenic shock models currently used for assisted circulation research are mentioned. Our own method called selective peripheral coronary embolization is presented in detail with its anatomic, pathologic-histologic and electrocardiographic pattern. Polyester fibrils are embolized selectively to the posterior wall of the heart by direct puncture of the circumflex branch of the left coronary artery. Shock hemodynamics and the effects of circulatory assist by the pneumatically driven ellipsoid ventricle (ELVAD) are demonstrated in 20 acute calf experiments. The artificial ventricle was inserted to the circulation between the natural left ventricle and the thoracic aorta in a paracorporeal and intrathoracic position. ELVAD activation was followed by a significant decrease of left ventricular pressure (-65%) and left atrial pressure (-35%). Cardiac index was increased by 10% and mean aortic pressure by 28% from their shock levels. Hemodynamics in irreversible ventricular fibrillation are analyzed in a calf experiment with a 40 hours survival only with ELVAD assist.

Animals↗
PubMed1979

[Acute mitral incompetence of ischemic origin (author's transl)].

Clinical findings and results of treatment in 17 patients with acute mitral incompetence are described. The lesions were secondary to a recent myocardial necrosis causing severe cardiac failure (shock, or acute left ventricular failure), and the presence of mitral incompetence was confirmed by right catherization (15 cases) and/or left ventricular angiography (13 cases). The anatomical lesions are described in 14 cases: rupture of the posterior mitral papillary muscle in 7 cases, and acute dysfunction of the muscle in 7 other cases. Eight patients were treated by an intra-aortic balloon to assist circulation, and 14 were given vasodilators (phentolamine, trinitrin) associated in 5 cases with positive inotropic drugs. Surgical treatment was given (mitral valve replacement) in 7 cases. The respective effects of vasodilators and circulatory assistance are discussed, as well as the indications for, and results of urgent surgical treatment (6 successes in 7 operations).

Acute Disease↗
PubMed1991

Sympathetic nerve activity during maintaining circulation with only left ventricular assist device.

Maintaining circulation with an left ventricular assist device (LVAD) alone during cardiac arrest until heart transplantation, was evaluated by the use of the sympathetic neurogram. To evaluate the influences of this method on autonomic nervous system, sympathetic neurogram was analyzed by power spectrum and coherence function. In acute animal experiments using mongrel dogs, LVAD were implanted. After the LVAD implantation, ventricular fibrillation was induced electrically. Renal sympathetic nerve activity (RSNA) was detected by the use of bipolar electrodes attached to the left renal sympathetic nerve. Values of squared coherence between the arterial pulse wave and RSNA were calculated. Under the condition of circulatory maintenance with LVAD, coherence at the cardiac rhythm frequency was decreased, and coherence at the LVAD pumping rhythm frequency was increased. These results suggest that the arterial pressure which was observed during maintaining the circulation with only LVAD contributed to sympathetic neurogram.

Animals↗
PubMed1987

Cardiopulmonary bypass after prolonged cardiac arrest in dogs.

Ventricular fibrillation (VF) cardiac arrest of more than ten minutes can be survived by cerebral neurons, but restoration of spontaneous circulation (ROSC) by external CPR is unreliable. Cardiopulmonary bypass (CPB) permits control of pressure, flow, oxygenation, temperature, and composition of blood. After 12 1/2 minutes of normothermic VF cardiac arrest, CPB was used as a research tool for reperfusion and assisted circulation for two hours in ten dogs without thoracotomy, with plasma substitute priming, and without preceding CPR (a deliberately nonclinical scenario). Recovery was compared with that in ten control dogs in which standard CPR with advanced life support (ALS) for up to 30 minutes was used to achieve ROSC. Both groups subsequently had blood pressure, blood gases, ventilation, and other parameters controlled for 20 hours, and intensive therapy to 72 hours. CPB achieved ROSC more successfully (ten of ten vs six of ten controls) (P less than .05), and more rapidly, with fewer defibrillation attempts and with less epinephrine (P less than .05). CPB improved 72-hour survival (seven of ten vs two of ten controls) (P = .025). Between two and 24 hours, of those with ROSC, intractable cardiogenic shock killed four of six control dogs (NS). CPB was followed by fewer arrhythmias. CPB increased recovery of consciousness (five of ten CPB vs zero of six controls with ROSC) (P = .037), but achieved neurologic normality in only one of ten. Cardiac arrest and CPB (without CPR) resulted in less myocardial morphologic damage than did standard CPR (P less than .025).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

[Progress in heart transplantation].

Within the past 10 years, heart transplantation has become established as a standard procedure in heart surgery. Improvements in immunosuppressive therapy and diagnosis of graft rejection have been crucial. The criteria for transplantation have been broadened for recipients as well as for donors. Newborns, pediatric patients, diabetics, and patients with impaired renal function will no longer be excluded from transplantation due to improved postoperative therapy. Furthermore, progress has been made with assisted circulation. Patients with acute heart failure can now be bridged to transplantation.

Adult↗
PubMed1994

Transesophageal echocardiography in children with cardiac assist.

Transesophageal echocardiography (TEE) is an easy, relatively non-invasive method for evaluation of cardiac function and abnormalities during cardiac assist. We used 19 TEE in 9 children (age: 10 days-4 years, weight: 2.7-12 kg) with mechanically assisted circulation for postcardiotomy cardiogenic shock. TEE provided valuable information: (1) dislocation of the cannula causing hemodynamic instability could be easily diagnosed and corrected; (2) Doppler evaluation of valvular function revealed severe malfunction in two patients; (3) intracardiac thrombus could be clearly detected in two children with seriously impaired hemodynamics. These findings were followed by therapeutic interventions; (4) left-ventricular function before attempted weaning from cardiac assist was moderately reduced or normal in the survivors, but poor in the nonsurvivors. We conclude that TEE is a valuable contribution to improved patient management during cardiac assist.

Child, Preschool↗
PubMed1995

Efficacy of a skeletal muscle-powered dynamic patch: Part 1. Left ventricular assistance.

In this study, we examined the capability of a skeletal muscle-powered, dynamic patch to provide left ventricular assistance. An actuator was developed that used linear traction power furnished by the latissimus dorsi muscle and liquid as the medium for power transfer. The proximal portion of the muscle was dissected and was reattached to the actuator. The left ventricular apex was excised, and the dynamic patch lined with autologous pericardium was implanted during cardiopulmonary bypass. Hemodynamic studies were performed in 8 dogs after weaning from cardiopulmonary bypass. Muscle stimulation was found to significantly increase the systolic aortic pressure (91.6 versus 112.1 mm Hg; p < 0.01), the mean aortic pressure (65.2 versus 73.0 mm Hg; p < 0.01), and aortic blood flow (0.77 versus 0.92 L/min; p < 0.01). The left atrial pressure decreased from 17.9 to 16.6 mm Hg (p < 0.01). This "hybrid" left ventricular assist device possesses notable clinical advantages because of its remarkable efficacy in assisting circulation. Further experimental studies using preconditioned skeletal muscle are necessary to assess the long-term effects of this technique.

Animals↗
PubMed2002

Extracorporeal membrane oxygenation and left ventricular assist device: a case of double mechanical bridge.

A 14-year-old boy with dilated cardiomyopathy with cardiac arrest was successfully implanted with a left ventricular assist device (LVAD) after 6-day extracorporeal membrane oxygenation (ECMO). He had multiple organ failure at the initiation of ECMO, but the failed organs recovered during assisted circulation, leading to LVAD implantation. This case showed the advantages of the "double bridge" such as: (1) quick and easy installation for acute cardiogenic shock, (2) providing intervention time for complications refractory to LVAD implantation, and (3) providing evaluation time for potential LVAD implantation and transplant candidates.

Adolescent↗
PubMedDate not supplied

Anticoagulation during use of a left ventricular assist device.

Thirty-six mongrel dogs underwent 24hr left ventricular assist. The VAD was placed between the left atrium and the descending aorta, and the dogs were divided into four groups according to type of anticoagulation: no anticoagulation, argatroban, nafamostat mesylate, and nafamostat mesylate + prostacyclin analog. Results of this animal experiment revealed that a newly developed synthetic thrombin inhibitor argatroban can prevent activation of the intrinsic coagulation pathway. Argatroban is efficient under any blood coagulative condition, even lack of anti-thrombin III, because of its direct inhibitory effect on thrombin, making argatroban more useful than heparin as an anticoagulant for LVAD. Argatroban, as well as heparin, provides marked and significant prolongation of the prothrombin time from early assisted circulation, but produces a bleeding tendency. Nafamostat mesylate can maintain blood coagulation parameters within the acceptable range. Combined administration of nafamostat mesylate and a prostacyclin analog cause the least decrease in fibrinogen and alpha2-plasmin inhibitor among the four groups and causes no significant prolongation of prothrombin time.

Animals↗
PubMed1989

[Selection of candidates for a ventricular assist device as a bridge to heart transplantation].

This study was undertaken to see how many people could receive the ventricular assist device (VAD) as a bridge to heart transplantation and to get selection criteria of the recipient. From January 1984 to December 1987, 9916 patients were admitted to our institute and 399 cases of them were dead. All dead cases were examined in terms of age, heart disease, other organ function, infection, and so on. There were 42 possible candidates for VAD, 31 men and 11 women. The average age was 50 years with a range from 22 to 63 years. Ten cases (23.8%) of them had the indication for VAD bridge to transplantation. The criteria for transplantable patients included the following three categories: I) Cardiogenic shock: Irreversible left or double ventricular failure with or without life-threatening dysrhythmia during IABP therapy--4 cases. II) End-stage valvular heart disease; Operation under VAD stand-by--2 cases. III) Postoperative refractory ventricular pump failure: Failure to wean from assist circulation after IABP trial or sustained ventricular failure under IABP support--4 cases. It was indicated that continuous precise evaluation of the deteriorating hemodynamics and the intensive care for major organ functions (renal, pulmonary, neurologic, hepatic, coagulation, etc.) were important to select the candidate for VAD bridge to heart transplantation.

Adult↗
PubMedDate not supplied

Development of an antithrombogenic and antitraumatic blood pump: the Gyro C1E3.

The Gyro C1E3 is a centrifugal blood pump. Its antithrombogenic and antitraumatic blood features were demonstrated by prior studies. Based upon these studies, a mass production model of the C1E3 is becoming commercially available. Therefore, this feasibility study was conducted using the mass production models of the Gyro C1E3 for long-term cardiac assist in ex vivo animal experiments. Five healthy calves were used and 15 pump heads were applied for different time periods (Group 1, 30 days; Group 2, 14 days; Group 3, 10 and 7 days; Group 4, 4 days; and Group 5, 2 days). Activated clotting time (ACT) was kept at 200-250 sec. All five calves demonstrated neither abnormal signs nor abnormal blood examination data throughout the experiment. During necropsy, no thromboembolism was found in any downstream organs. Groups 1-4 showed thrombi inside the pump heads while two pumps in Group 5 had no thrombi formations. Bearing deformation or possible wear did not increase after 2 days of pumping. The C1E3 is capable of long-term assist circulation. However, after 2 days of pumping, careful observation is necessary since thrombi may occur inside the pump when ACT is controlled under 250 sec. During the weaning stage or low flow (under 2 L/min), over 250 sec of ACT is recommended to assure the safety of the patient.

Animals↗
PubMed1997

Chronic animal experiment with magnetically suspended centrifugal pump.

We have been developing a new type of centrifugal pump for long-term use. The magnetically suspended centrifugal pump (MSCP) contains no shaft and seal so that long life expectancy is predicted. Paracorporeal left ventricular (LV) assist circulation between the left atrium and the descending aorta was instituted using sheep. The flow rates ranged from 2.5-5.5 L/min. The sheep that lived the longest (46 days) died of an embolism as a result of the thrombus in the pump. No thrombus formation was observed in other pumps. Plasma free hemoglobin levels ranged from 9 to 18 mg/dl, which led to the conclusion that the hemolysis level remained within an acceptable range. Two driving modes were compared. The slope of the pressure-flow relationship plot under a constant motor current mode was steeper than that under a constant rotational speed mode, and thus, the flow fluctuation decreased. In conclusion, the MSCP is durable for more than a month at the current stage of development and is a promising device for long-term ventricular assist.

Animals↗
PubMed1999

Total vascular resistance and blood flow frequency during left ventricular assistance using a vibrating flow pump.

A vibrating flow pump (VFP) can generate high frequency oscillated blood flow within 10-30 Hz by the oscillation of its central tube. A totally implantable artificial heart using a VFP is being developed as a unique type of blood pump. In this study, left ventricular (LV) assist circulation was performed using a VFP. The total vascular resistance and driving frequency of the VFP were estimated from their relationship. The effect of oscillation on the vascular system was studied by the frequency analysis method and vascular impedance. Adult goats were anesthetized by halothane using an inhaler and a left fourth thoracotomy was performed. The inflow cannula was inserted into the left ventricle, and the outflow cannula was sutured to the descending aorta. The VFP and a centrifugal pump were set in parallel for alternation and comparison. The driving frequency of the VFP was changed and included 15, 20, 25, and 30 Hz. The hemodynamic parameters were continuously recorded during experiments by a digital audio tape (DAT) data recorder. The internal pressure of the left ventricular cavity and aortic pressure were monitored by the pressure manometers continuously. One hundred percent LV assistance was judged by the separation of LV and aortic pressure. The total vascular resistance was decreased by the start of operation of each pump. The decrease during flow using the VFP was not as large as that using a centrifugal pump (CP). The arterial input impedance during oscillated blood flow by the VFP showed a slow curve appearance. It was similar to the frequency characteristics curve of natural heart beats within the lower frequencies. The study of arterial impedance may be important for the estimation of the reflection of the pulsatile wave from the arterial branch, among other things.

Animals↗
PubMed2003

New experience with the paracardial right ventricular axial flow micropump impella elect 600.

Beating heart surgery is still challenging and could be made safer using assisted circulation. We evaluated clinical outcome following beating heart myocardial revascularisation using the impella elect system with intracardial left ventricular (LV) and paracardial right ventricular (RV) microaxial pumps in eight patients. Clinical course was uneventful. There were no device-related complications. The paracardial design of the RV-pump is a great advantage compared to the former intracardial design because it eliminates arrhythmia and LV hypovolemia. Support by microaxial pumps can make beating heart surgery safer and applicable for more complex cases.

Aged↗
PubMed1995

Suggested set-up and layout of instruments and equipment for advanced operative laparoscopy.

Crucial elements that ensure the organization and smoothness of a laparoscopic procedure are clear communication among well-trained endoscopy team members, properly maintained equipment, and a sensible layout of the instruments. The team consists of the surgeon, surgical assistant, circulator, scrub nurse, laser nurse, and anesthesiologist. To promote continuity and interaction and to ensure a systematic, pleasant pace for laparoscopic procedures, the team should establish a specific routine, as well as set-up and layout of tables, equipment, and instruments. Key ingredients for advanced operative laparoscopy to be performed with optimum efficiency and effectiveness are the best organization and placement of the equipment, instrumentation, and team in a particular setting in the operating room.

Anesthesiology↗
PubMed1994

Use of left-ventricular assist with the Hemopump in cardiac surgery.

From July 1989 to May 1992 16 patients received circulatory support with a Hemopump assist device in the Department of Cardiac Surgery of the Katholieke Universiteit Leuven. The mean age of those patients was 56 +/- 13 years (ranging from 23 to 72 years). The mean time of assisted circulation was 60 +/- 46 h (ranging from 2 to 168 h). Group I consists of 13 patients who received the device after postcardiotomy cardiac failure (survival 38%). Group II includes 1 patient who received the pump prior to repair of a large postinfarction ventricular septal defect (survival 10%). Group III consists of 2 patients for whom the Hemopump was used as a bridge to cardiac retransplantation. Both are still alive (survival 100%). If the 21-F Hemopump is implanted following a critical indication it can be used rather successfully for mechanical circulatory support.

Adult↗