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The objective of this study was to analyze the early predictive factors for successful weaning from a percutaneous cardiopulmonary support system (PCPS) in patients with low cardiac output syndrome after cardiovascular surgery. A total of 938 patients underwent cardiovascular surgery with cardiopulmonary bypass (CPB) from January 1991 to September 2006 at Gunma University Hospital. Of these 938 patients, 13 (1.4%) required PCPS to maintain hemodynamics within 48 hours after surgery. The mean age of the 13 patients was 66 years (range, 45 to 86 years). Nine patients underwent open-heart surgery, 3 repair of a thoracic aortic aneurysm, and 1 a pericardiectomy. The patients were divided into 2 groups; group A (n = 4) who were removed from PCPS and group B (n = 9) who were not removed from PCPS. The conditions during the operation and after PCPS support were compared between the 2 groups. The mean age was higher, and operation time, CPB time, and aortic cross-clamping time were significantly (P < 0.05) longer in patients with PCPS than in those without PCPS. The mean PCPS time in all 13 patients was 190 +/- 122 hours. The mean age was higher, and CPB time and the aortic cross-clamping time were longer in group B than in group A (NS). The mean duration of PCPS support was significantly (P < 0.05) shorter in group A than in group B (117 +/- 42 hours versus 235 +/- 136 hours). PCPS flow in group A could be reduced from 48 hours after PCPS induction. However, PCPC flow in group B could not be reduced, and there were significant (P < 0.05) differences in PCPS flow at 72 and 96 hours after starting PCPS. Significant (P < 0.05) differences in the absolute values of the APACHE II score, serum lactate levels, administered epinephrine dose, and levels of total bilirubin (T-Bil), serum creatinine (sCr), and lactate dehydrogenase (LDH) were found between the 2 groups within 96 hours after PCPS induction. In addition, there were significant (P < 0.05) differences in the rate of change compared with the baseline control value obtained prior to PCPS use in PCPS flow, APACHE II score, and levels of T-Bil, sCr, and LDH within 96 hours after PCPS induction. Significant differences in the rate of change of sCr and LDH were found, especially from the early phase after PCPS use, compared with other parameters. In the patients removed from PCPS, PCPS flow could be reduced within 48 hours after commencement of PCPS. Improvements in the APACHE II score and biochemical variables within 96 hours appear to be reliable prognostic factors for PCPS patients.

A specific cannula allowing single site transaortic inflow and outflow cannulation for centrifugal assist devices is described. The cannula is inserted through a straight 18 mm collagen coated Dacron tube anastomosed to the anterior aspect of the ascending aorta. The inflow conduit of the cannula is positioned into the left ventricle through the aortic valve, and the end hole of the outflow conduit is positioned in the ascending aorta. The cannula was evaluated in vivo in 3 adult pigs by the institution of a centrifugal pump for left ventricular support. Optimal flow varied between 5 and 6 L/min and mean aortic pressure between 55 and 70 mm Hg throughout the 3 days of left ventricular support. Recently, we employed this cannula in a patient who was not able to be weaned from cardiopulmonary bypass for the institution of left ventricular support using a centrifugal pump. The cannula provided effective inflow and outflow drainage with an optimal flow of 5.2 L/min throughout the 72 h of support. The patient was successfully weaned from support on the fourth postoperative day. This rational transaortic approach of cannulation using this specific cannula is a refined implantation technique which allows direct left ventricular inflow drainage, reduces the time of implantation, spares left ventricular myocardium, avoids bleeding that is sometimes encountered at other cannulation sites, and avoids compression of the heart by cannulas.

We evaluated the efficacy and problems of circulatory support with percutaneous cardiopulmonary support (PCPS) for severe cardiogenic shock and discussed our strategy of mechanical circulatory assist for severe cardiopulmonary failure. We also described the effects of an alternative way of PCPS as venoarterial (VA) bypass from the right atrium (RA) to the ascending aorta (Ao), which was used recently in 3 patients. Over the past 9 years, 30 patients (20 men and 10 women; mean age: 61 years) received perioperative PCPS at our institution. Indications of PCPS were cardiopulmonary bypass weaning in 13 patients, postoperative low output syndrome (LOS) in 14 patients, and preoperative cardiogenic shock in 3 patients. Approaches of the PCPS system were the femoral artery to the femoral vein (F-F) in 21 patients, the RA to the femoral artery (RA-FA) in 5 patients, the RA to the Ao (RA-Ao) in 3 patients, and the right and left atrium to the Ao in 1 patient. Seventeen (56.7%) patients were weaned from mechanical circulatory support (Group 1) and the remaining 13 patients were not (Group 2). In Group 1, PCPS running time was 33.1 +/- 13.6 h, which was significantly shorter than that of Group 2 (70.6 +/- 44.4 h). Left ventricular ejection fraction was improved from 34.8 +/- 12.0% at the pump to 42.5 +/- 4.6% after 24 h support in Group 1, which was significantly better than that of Group 2 (21.6 +/- 3.5%). In particular, it was 48.6 +/- 5.7% in the patients with RA-Ao, which was further improved. Two of 3 patients with RA-Ao were discharged. Thrombectomy was carried out for ischemic complication of the lower extremity in 5 patients with F-F and 1 patient with RA-FA. One patient with F-F needed amputation of the leg due to necrosis. Thirteen patients (43.3%) were discharged. Hospital mortality indicated 17 patients (56.7%). Fifteen patients died with multiple organ failure. In conclusion, our alternate strategy of assisted circulation for severe cardiac failure is as follows. In patients with postcardiotomy cardiogenic shock or LOS, PCPS should be applied first under intraaortic balloon pumping (IABP) assist for a maximum of 2 or 3 days. In older aged patients particularly, the RA-Ao approach of PCPS is superior to control flow rate easily, with less of the left ventricular afterload and ischemic complications of the lower extremity. If native cardiac function does not recover and longer support is necessary, several types of ventricular assist devices should be introduced, according to end-organ function and the expected support period.

A great number of patients suffer and die from the sequelae of acute and chronic heart failure each year. Although advances in medical and surgical therapy have benefited many of these patients, the majority suffer from disease refractory to any definitive therapy. For these patients, cardiac transplantation is the only remaining hope. Unfortunately, because of the increasing demand for donor organs in the face of a fixed and limited supply, this option is only available to a small percentage of these patients. Even in patients accepted for transplantation, a significant waiting list mortality has been observed. A variety of ventricular assist devices (VAD) have been developed since the first successful case of mechanical cardiac assistance over 30 years ago. These devices differ in basic mechanical function, method of insertion, and degree of implantability, and thus have different indications and potential applications. While the intra-aortic balloon pump and centrifugal pumps are effective short-term support modalities, extracorporeal and implantable pulsatile devices have been used successfully for long-term support of patients with reversible and non-reversible cardiac failure. These pumps have most commonly been utilized as bridges to transplantation, but increasing clinical experience has supported the notion of long-term mechanical assistance as a definitive therapy for endstage heart disease. While complications, particularly infection and thromboembolism, pose significant challenges and long-term device reliability remains to be fully determined, available implantable devices seem capable of providing effective long-term support. As data is obtained from currently ongoing trials comparing VAD support to medical therapy for endstage heart failure, ethical and economic issues will assume increasing importance.

Extracorporeal membrane oxygenation (ECMO) was initially developed for respiratory failure. Its use, however, has evolved into an excellent method of preoperative and postoperative support in the treatment of infants and children with acquired and congenital heart disease. Along with ECMO, the left ventricular assist device (LVAD) and the intraaortic balloon pump (IABP) have also found a place in the management of paediatric patients with heart failure. This report documents 15 patients who were treated with one or a combination of these mechanical devices, either preoperatively or postoperatively. There is a 74% survival rate and the long-term outcome has been excellent in most cases. The use of heparin-coated devices and tight regulation of heparin has allowed the transfer of infants and children from standard cardiopulmonary bypass to assist devices in the operating room. Mechanical devices are an essential adjunct for the preoperative and postoperative treatment of infants and children with cardiac disease.

Between January 1990 and September 1992, ten patients required assisted circulation for postcardiotomy heart failure which was unresponsive to inotropic drugs and aortic counterpulsation. All patients were supported by a Bio-Medicus centrifugal pump (biventricular assist in five, left ventricular in three, right ventricular in two); six had ischaemic heart disease, two a congenital ventricular septal defect, one an acute mitral valve incompetence and one an aortic type 'A' dissection. The mean duration of circulatory support was 5.1 days (range 2 hours to 8 days). Six patients were weaned from the device and four were discharged; the perioperative deaths among the patients weaned from support were the result of cerebral haemorrhage and multiorgan failure respectively. No late deaths occurred at a mean follow-up of 15 months. Common complications were bleeding (40%), acute renal failure (30%) and sepsis (30%). All patients who developed renal failure died. The high incidence of haemorrhagic complications makes the use of pre-heparinized circuits desirable as these patients do not then require additional anticoagulation.

We have invented a mechanical circulatory assist system that uses a heparin-coated tube and a roller pump. Experimental left heart bypass was performed on 13 mongrel dogs for 24 hours without systemic heparinization. There were no significant changes in coagulation variables during the experiment, and pathological examination of internal organs after bypass revealed no evidence of thromboembolism. We applied this assist system to 13 patients who could not be weaned from cardiopulmonary bypass after an open heart operation. Left heart bypass was performed on 7 patients, right heart bypass on 1 patient, combined left and right heart bypass on 2, and venoarterial bypass without oxygenation on 3. Duration of support ranged from 5 hours to 21 days, and the pump flow rate ranged from 0.8 to 3.2 L/min. Eight patients were successfully weaned from this support, and 6 were discharged from the hospital. Examination of the tubes in the assist system revealed excellent antithrombogenicity for at least 3 days without systemic heparinization. There was no evidence of thromboembolism in brain, kidneys, lungs, or other organs. Because of its simplicity and antithrombogenicity, this mechanical assist system is beneficial for patients who cannot be weaned from cardiopulmonary bypass after open heart operations.

A previously well 53-year-old man with fulminant myocarditis is presented. Cardiogenic shock and medically refractory low cardiac output syndrome were unsuccessfully treated using an intraaortic balloon pump. A percutaneous extracorporeal bypass system improved hemodynamics, DIC and other multiorgan injuries following acute myocarditis.

The model of the failure of the right ventricle was formed in dog experiments. The animals were connected with the right mechanically assisted circulation. The blood was pumped synchronously with the heart action from the right atrium directly to the pulmonary artery by temporary bypass of the right ventricle. The right volume relief improved (p less than 0.03) the decisive hemodynamic parameters. The value of assisted circulation in case of the hitherto only difficulty to controlled failure of the right ventricle is proved with that.

A patient had right ventricular infarction complicated by cardiogenic shock. Volume expansion along with high doses of dopamine hydrochloride successfully alleviated hypotension in this patient. However, he had persistent mental obtundation and low cardiac output, and adverse chronotropic responses to high doses of dopamine developed. Counterpulsation effectively maintained an adequate arterial pressure and dopamine therapy was discontinued. Counterpulsation, however, failed to augment cardiac output. Simultaneous use of dobutamine hydrochloride along with counterpulsation was associated with a noticeable increase in cardiac output. To our knowledge, this is the first reported case of right ventricular infarct complicated by shock in which the simultaneous use of counterpulsation and dobutamine therapy resulted in a substantial increase in cardiac output.

At the present time mechanical assisted circulation is indicated in patients with cardiac failure after open heart operations. The results after clinical implantation of the left ventricular assist devices are not encouraging. However, most of these patients suffer from irreversible cardiac failure and no restitution is to be expected. In patients with postoperative cardiac failure, a distinction must be made between isolated left heart failure and total heart failure. In patients with total heart failure - for example with diffuse, marked coronary sclerosis - both left and right ventricle failure exists. In these patients, no left ventricular assist device per se can bring the desired effect, since due to the right heart failure syndrome, the left system does not work adequately. With the biventricular bypass it is possible to maintain complete circulation in cases of cardiac insufficiency. The cannulation concept is biventricular transatrial to the aorta or to the pulmonary artery. The technique is simple and can be carried out very quickly. In cases of clinical emergency this device can be recommended due to the satisfactory haemodynamic effects achieved and the small degree of traumatic haemolysis. It represents an easy and quick implantable system for total functional heart replacement.

The effect of combined treatment of coenzyme Q10 (CoQ10) and aprotinin with intra-aortic balloon pumping (IABP) was evaluated in patients who underwent aorto-coronary bypass surgery. Forty-one patients were divided into two groups. Group A (27) were treated by IABP only and Group B (14) were treated by the concomitant use of CoQ10 and aprotinin with IABP. Both groups were subdivided into two groups with regard to the ability to be weaned from IABP (Group A-I, Group B-I) or the inability (Group A-II, Group B-II). CoQ10 was administrated intravenously at doses of 5-10 mg/kg/day and aprotinin was infused at doses 5,000-10,000 KU/kg/day. The percentile incidence of ability to be weaned from IABP was 93 per cent (13/14) in Group B was higher than that of 74 per cent (20/27) in Group A. There were no significant differences among Group A-I, Group A-II, and Group B-I with regard to preoperative and intraoperative factors. Serum GOT and CPK levels on the first postoperative day were significantly higher in Group A-II and Group B-I than those in Group A-I but there was no significant difference between GOT or CPK levels in Group A-II and Group B-I. These results suggest that concomitant treatment of CoQ10 and aprotinin with IABP leads to an improvement in postoperative low cardiac output syndrome.

A new, simple left ventricular assist system has been developed and its use in experimental animals has been evaluated. The system achieves ventricular drainage by a transaortic valve cannula and utilizes a new centrifugal pump; the blood access is unique in requiring only a simple end-to-side synthetic graft anastomosis to the ascending aorta. Adequate pulsatility is obtained by concomitant use of an intraaortic balloon pump. This case report documents our initial clinical experience with this system in a postoperative patient with profound left ventricular failure unresponsive to all usual treatment. There was temporary recovery of left ventricular function upon decannulation after five and a half days of assist pumping. Despite the eventual death of the patient, the system functioned adequately, suggesting that it has good potential for use in a small, selected group of patients.

Various forms of circulatory assist devices are currently under investigation. Clinical use of ventricular bypass devices ranging from roller-pump-driven units to pneumatically powered VADs have been in use for several years. These devices are indicated for patients in cardiogenic shock following cardiac surgery or myocardial infarction when all other forms of conventional therapy have failed. Success, though modest, is encouraging in these patients with a dismal prognosis. An increasing role for the VAD may be found in supporting patients whose condition deteriorates while awaiting cardiac transplantation.

A paracorporeal left ventricular assist device (LVAD) with a capacity to pump 8 L/min of blood was employed in a clinical trial, and this report details the first survivor. A 60-year-old man could not be separated from the pump oxygenator following coronary artery bypass grafting, and, therefore, an LVAD was employed. Almost the entire left ventricular workload was assumed by the mechanical pump so that the myocardium was allowed to rest and recover. The LVAD support was continued for 105 hours. It provided satisfactory total body perfusion with maintenance of good hemodynamics--without serious deleterious effects on hematologic factors. The patient is alive and active without cardiac symptoms 16 months after his operation. The total experience with 13 LVAD implantations warrants continuation of the clinical trials in selected patients.

Treatment of postcardiotomy low-output syndrome includes intraaortic balloon pumping (IABP), volume loading, pharmacological afterload reduction, and stimulation with an inotropic agent. This study compares the effectiveness of combined nitroprusside and dopamine therapy and nitroprusside and dobutamine therapy in 12 patients requiring IABP postoperatively. Serial hemodynamic measurements were made before and during infusion of nitroprusside and after administration of the combined therapy (N = 6 in each group). Prior to pharmacological therapy, cardiac index was 1.47 +/- 0.31 L/min/m2 and systemic vascular resistance (SVR) was 3,114 +/- 1,350 dynes sec cm-5 in patients subsequently given dopamine, and 1.59 +/- 0.38 L/min/m2 and 2,661 +/- 405 dynes sec cm-5, respectively, in those given dobutamine. With infusion of nitroprusside, both groups showed significant reduction in SVR. Nitroprusside plus either inotropic agent resulted in augmentation of cardiac index and an additional reduction in SVR, both changes being greater in the group given dopamine. Larger doses of dobutamine than dopamine were needed to achieve similar hemodynamic improvement. We conclude that the addition of an inotropic agent to vasodilator therapy during IABP results in a greater increase in cardiac index and a greater decrease in afterload than a vasodilator alone. In addition to its beneficial effect on renal perfusion at the dose required to effect these improvements, dopamine appears a better inotropic agent than dobutamine for postcardiotomy low-output syndrome.

Right ventricular failure following cardiac surgery must be rapidly diagnosed and treated to minimize injury to the heart. Switching from aortic to pulmonary artery perfusion during cardiopulmonary bypass is a method of rapidly testing the adequacy of right ventricular function and supporting the ventricle if necessary. A centrifugal pump has been used for long-term support for two cases managed in this manner.

From June, 1977, to December, 1978, 14 children had intraaortic balloon support after open-heart operation. There were 6 long-term survivors. Four of 5 children more than 10 years old and 2 of 5 children between 5 and 10 years old survived. All 4 children less than 5 years old died. In the youngest group, it was difficult to use the balloon successfully because of their very low cardiac output coming off bypass and their greater aortic elasticity. The smallest sizes of balloon available were found to be too long, extending well below the diaphragm in younger patients. In 7 out of 10 patients 5 years old or more, augmentation was obtained.

Intraaortic balloon pumping and atrial pacing are both useful in treating postoperative low output syndrome. However, the electrocardiographic atrial pacing spike can interfere with the electrocardiogram tracking mechanism of many balloon consoles. Bipolar epicardial pacing can avoid this problem and allow simultaneous atrial pacing and intraaortic balloon pumping.

Intra-aortic balloon pumping (IABP) has been utilized in our institution in over 600 patients for the treatment of postcardiotomy low-output syndrome, with a 59% survival rate. Volume loading and pharmacologic treatment have played integral roles in the overall treatment of this syndrome. This investigation documents the hemodynamic effectivenss of combined nitroprusside/dopamine therapy in patients who required IABP for weaning from cardiopulmonary bypass. Serial hemodynamic measurements were made before and during infusion of nitroprusside (0.5 to 5.0 microgram/kg/min) and after combined nitroprusside/dopamine (7.5 micrograms/kg/min) therapy in 10 patients during IABP. Prior to pharmacologic therapy, cardiac index was 1.6 +/- 0.4 L/min/m2 and systemic vascular resistance (SVR) was 2,774 +/- 932 dynes sec cm-5. After nitroprusside infusion, cardiac index increased to 1.8 +/- 0.5 L/min/m2 (NS) and SVR decreased to 1,957 +/- 791 dynes sec cm-5 (p less than 0.01). The simultaneous infusion of nitroprusside and dopamine resulted in further augmentation of cardiac index to 2.5 +/- 0.5 L/min/m2 (p less than 0.01) and an additional reduction of SVR to 1,439 +/- 358 dynes sec cm-5 (p less than 0.02). In addition, pressure-rate-product, an index of myocardial oxygen demand, was decreased by nitroprusside (p less than 0.02) but was not significantly altered by both agents. This study provides a rationale for the combined use of nitroprusside/dopamine in postcardiotomy low-output syndrome necessitating IABP when SVR is greater than 2,000 dynes sec cm-5 and cardiac index is less than 2.0 L/min/m2.

Comparisons of the physiologic bases of intraaortic balloon and extracorporeal or implantable left ventricular assist device or partial artificial heart pumping in experimental and clinical setting are made. The concepts and first principles common and unique to both of these forms of mechanical circulatory support are presented with emphasis on the similarities and important differences. Intraaortic balloon counterpulsation is examined as an intravascular, volume displacement device in series with the systemic circulations. Left ventricular assist devices are analyzed as extravascular in-series or parallel volume-capturing/ejecting devices and as true blood pumps which can be implanted. The interrelated mechanisms of synchronous, diversion/counterpulsation/diastolic augmentation are discussed in relation to quantitative indices of myocardial ischemia, myocardial oxygen supply/demand ratios, the Sarnoff theorem and the Laplace relationship, vis à vis ventricular unloading/impedance reductions. Some of the many clinical settings of IABP are mentioned, along with hydraulic considerations which allow non-invasive determination of stroke volume during clinical IABP mechanical circulatory support. Cardiogenic shock/left ventricular failure/low cardiac output are defined in terms of failure to generate pressure and displace volume and deficits of ejection fraction and stroke volume. Vasodilator therapy (nitroprusside), IABP, and LVAD are then viewed as escalating methods of reversing these deficits. Finally, pressure volume loops of the human left ventricle are compared with those of LVADs, experimentally and clinically, to indicate that LVADs can function and support the circulation during all low output states including ventricular fibrillation and standstill. Representative hemodynamic traces (Fig. 5 and 6) obtained during clinical LVAD trials in man are included to illustrate these theoretical and practical considerations. The use of LVADs in any instance of IABP inadequacy is implicit and inferred.

Antithrombogenicity of pneumatic ventricular assist devices (VAD) for postoperative ventricular failure was evaluated macroscopically and microscopically in relation to VAD flow, coagulation parameters, and other potentially thrombogenic factors. A total of 12 sack type pumps were used in nine cases after operations for ischemic heart diseases (4 cases), valvular diseases (3 cases), and congenital anomalies (2 cases). Durations of pumping of each device ranged from 18 hours to 37 days (mean, 10.9 days). The clinical protocol for antithrombogenicity of the device indicates maintenance of ACT around 150 sec and keeping VAD flow more than 2.0 L/min. In our clinical series, however, heparin was given only in most cases to maintain activated clotting times (ACT) at 120-140 sec for the first three postoperative days. Minute ringlike thrombi were noted at connectors of cannula in two pumps after low flow (1.5 L/min) pumping for 5 days or after frequent on/off studies for weaning. A small thrombus (2 X 2 mm) and fine granular thrombi were noted on actuating bladders in two pumps that were used with frequent on/off studies or in a patient with severe sepsis during VAD pumping. Other VAD pumps were macroscopically free of thrombus. SEM analyses on surfaces of actuating bladders demonstrated mild to moderate platelet adhesions, which were correlated with platelet count, but not with other coagulation parameters including platelet agglutination and pumping duration. In cases with leucocytosis during VAD uses, leucocyte adhesion was noted as well without correlation to the coagulation parameters.

Temporary femorofemoral bypass, combined with intra-aortic balloon pump counterpulsation, was used as a final resort to salvage the life of patients with extremely low cardiac output at the end of cardiopulmonary bypass and in patients who had cardiac arrest perioperatively who were unresponsive to conventional methods of resuscitation. Eight of 15 patients survived initially, 7 of them left hospital and remain well. These data are comparable to results obtained with the newly developed, but not readily available, left ventricular assist devices. The combination of femorofemoral bypass and intra-aortic balloon pump counterpulsation represents an important practical alternative as it can be used successfully for temporary cardiac support in critical situations, is potentially life-saving and is readily available at any cardiac centre at minimal cost.

During ventilation, the lungs may serve as accessory pumps for forward blood flow. We have noted significant hemodynamic improvement in several patients during short periods of vigorous hand ventilation with the Ambu bag and tried to reproduce the hemodynamic improvement in the management of four patients with profound low cardiac output syndrome secondary to right ventricular (RV) failure following open heart surgery. High frequency, high volume (HFHV) ventilation resulted in improved hemodynamics in these patients, as evidenced by pulsatile pulmonary blood flow and increased cardiac output. Right-sided stroke work was present and there was a fall in mean central venous pressure (CVP) and rise in mean pulmonary artery pressure (PAP).