Usefulness of postoperative percutaneous cardiopulmonary support using a centrifugal pump: retrospective analysis of complications

Clinical results and pump analysis of the Gyro pump for long-term extracorporeal life support

Rescuing patients in severe cardiac failure with extracorporeal support remains challenging. The Gyro pump is a centrifugal blood pump and was now used for cardiopulmonary bypass, although it was originally developed for long-term cardiac assist. Little is known about clinical experiences using this pump. Here, we report on the clinical results of long-term extracorporeal life support for over 4 days using the Gyro pump with Excelung, a hollow fiber oxygenator coated with silicone and heparin. Seven patients underwent extracorporeal life support with 15 pump and oxygenator combinations. Gyro and Excelung were used for venoarterial extracorporeal support in six patients and for right ventricular support in one patient. Patient characteristics, pump driving conditions, and blood chemistry were obtained retrospectively. All pumps were subsequently disassembled and examined macroscopically, with 6 of 15 pumps also examined by scanning electron microscopy (SEM). The patient mortality rate was 57.1%. Mean duration of support was 10.5 ± 7.2 days per pump and oxygenator combination. Lactate dehydrogenase and aspartate aminotransferase were generally maintained below 1000 and 100 IU/L, respectively, after the first 4 days of pump driving. Thrombi were found in two pumps, one used without anticoagulation and the other driven at a very slow rotational speed. SEM revealed no wear in the male bearings and very low wear and deformation (0.02 ± 0.03 mm) in the female bearings. The combination of Gyro and Excelung may be applicable for long-term biventricular and right ventricular support, although proper anticoagulation should be administrated to avoid thrombus formation inside the pump.

Active internal re-warming using a centrifugal pump and heat exchanger following haemorrhagic shock, surgical trauma and hypothermia in a porcine model

BACKGROUND

The centrifugal vortex blood pump (CVBP) using heparin-bonded circuitry allows re-warming of hypothermic trauma patients without anticoagulation. Study objectives were to confirm efficacy, and to characterise the physiology of CVBP re-warming in a porcine model.

METHODS

Sixteen pigs were randomised to conventional or CVBP re-warming. They were bled to a mean arterial pressure of 30 mmHg and cooled to 29 degrees C. A physiological analysis was recorded during resuscitation to normo-tension and re-warming back to 37 degrees C.

RESULTS

CVBP animals re-warmed significantly faster: 85.0+16.4 min versus 217.4+49.3 min (p<0.0001). Activated clotting time was significantly elevated in both groups at 29 degrees C with a marked trend to normalise faster in CVBP pigs. The peak cardiac index (CI) was significantly lower (1.14+0.68 versus 4.83+1.50 L/(min m2), while the systemic vascular resistance (SVR) was significantly higher (4239.9+1173.0 versus 1472.6+451.2 dyn x S x m2/cm5) with CVBP (p<0.001).

CONCLUSION

CVBP is simple and very effective at re-warming hypothermic animals and may also reverse coagulopathy more quickly. Physiological derangements of elevated SVR and diminished CI require further study to elaborate underlying aetiology, and define optimal re-warming strategies.

Limitation of venoarterial bypass. Early predictor and optimal conversion

Conversion from venoarterial bypass to a ventricular assist device may be lifesaving for patients with severe heart failure, but the criteria for conversion have not yet been established. Forty patients who underwent venoarterial bypass for cardiac failure were reviewed. Of these, 18 (45%) could be weaned from venoarterial bypass, and 11 survived for more than 30 days after weaning (survival rate, 27.5%). Liver dysfunction, renal dysfunction, and the need for left-sided cardiac venting were risk factors for mortality. The appearance of patient's own cardiac pulse wave within 24 hours after the introduction of venoarterial bypass was a good indication for weaning. Delayed appearance of the cardiac pulse wave was considered to be a risk factor for death. According to these indices, conversion from venoarterial bypass to a ventricular assist device should be considered to prevent deterioration in the function of systemic organs.

Back from Irreversibility: Extracorporeal Life Support for Prolonged Cardiac Arrest

BACKGROUND

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.

METHODS

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 +/- 15 years; the average time of external cardiac massage was 105 +/- 44 minutes.

RESULTS

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.

CONCLUSIONS

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.

Outcome of the Perioperative Use of Percutaneous Cardiopulmonary Support for Adult Cardiac Surgery: Factors Affecting Hospital Mortality

Percutaneous cardiopulmonary bypass support (PCPS) has become a widespread standard modality for the treatment of circulatory collapse; however, its clinical use for postcardiotomy low cardiac output syndrome (LOS) has been reported to be unsatisfactory. We reviewed the clinical outcomes of twenty-three patients undergoing cardiac surgery and treated with PCPS. Solitary coronary artery grafting was undertaken for nine patients, while three had concomitant procedures. The remaining patients underwent valvular surgery. The indications for PCPS were preoperative shock in two patients and postcardiotomy LOS or shock in twenty-one patients. All patients except one underwent an intraaortic balloon pump. Sixteen of the twenty-three patients (69.6%) were weaned from PCPS and twelve patients (52.2%) reached hospital discharge. A univariate analysis revealed that risk factors for hospital mortality were age older than seventy years (P = 0.05), PCPS running time (P = 0.017), low cardiac function at the institution of PCPS (P = 0.004), and urine output within the initial 24 h (P = 0.041). The cardiac index (CI) in survivors was improved within 24 h, and eleven of the twelve survivors were weaned off PCPS within 48 h, whereas ten of the twelve nonsurvivors required PCPS for more than 48 h (P = 0.0006). There is little possibility of weaning patients from PCPS who do not show any signs of hemodynamic recovery within 48 h after its institution. Limited use of PCPS within 48 h may be applicable for postcardiotomy patients, but other cardiopulmonary support, such as a left ventricular assist device, may be required when hemodynamic recovery is not obtained within 48 h.

Use of a Centrifugal Vortex Blood Pump and Heparin-Bonded Circuit for Extracorporeal Rewarming of Severe Hypothermia in Acutely Injured and Coagulopathic Patients

BACKGROUND

Standard rewarming methods for posttraumatic hypothermia are ineffective or require systemic heparinization. Centrifugal vortex blood pumps (CVBPs), heparin-bonded circuits, and, potentially, percutaneous access techniques, facilitate the institution of an extracorporeal circulation by noncardiac surgeons.

METHODS

Seven severely hypothermic patients requiring emergent operative intervention were rewarmed intraoperatively using the CVBP with heparin-bonded circuitry.

RESULTS

Patients were critically ill (average Injury Severity Score of 43.5 [SD, 13.6] for the traumatized patients). The mean temperature before rewarming was 31.5 degrees C (SD, 1.6 degrees C). The CVBP outflow site was the common femoral vein in all patients, with the inflow into the superficial femoral artery (n = 2), contralateral common femoral vein (n = 2), and internal jugular vein (n = 3). The mean time to rewarm to 37 degrees C was 73.3 (SD, 30.5) minutes. All patients survived the initial operation, although the ultimate survival was 43%.

CONCLUSION

Noncardiac surgeons can effectively use an extracorporeal rewarming strategy incorporating a heparin-bonded CVBP to rapidly rewarm hypothermic coagulopathic patients undergoing surgery.

Experience with percutaneous venoarterial cardiopulmonary bypass for emergency circulatory support

OBJECTIVE

Mechanical circulatory support can maintain vital organ perfusion in patients with cardiac failure unresponsive to standard pharmacologic treatment. The purpose of the current study was to report complication and survival rates in patients supported with emergency percutaneous venoarterial cardiopulmonary bypass because of prolonged cardiogenic shock or cardiopulmonary arrest.

DESIGN

Retrospective clinical study.

SUBJECTS

A total of 46 patients supported with venoarterial cardiopulmonary bypass, 25 because of cardiogenic shock unresponsive to pharmacologic therapy and 21 because of cardiopulmonary arrest unresponsive to standard advanced cardiac life support.

RESULTS

In 41 of the 46 patients (89%), stable extracorporeal circulation was established; in five patients (11%), femoral cannulation was accomplished only after a surgical cutdown. A total of 28 patients were weaned from cardiopulmonary bypass (19 of 25 patients with cardiogenic shock vs. 9 of 21 patients with cardiopulmonary arrest, p =.03), and 13 patients had long-term survival (10 of 25 patients with cardiogenic shock vs. 3 of 21 patients with cardiopulmonary arrest, p =.1). Complications directly related to the use of cardiopulmonary bypass were found in 18 patients (39%), major complications related to femoral cannulation being the most common single cause for bypass-associated morbidity (eight patients, 17%).

CONCLUSIONS

Long-term survival rates after emergency percutaneous cardiopulmonary bypass are encouraging in patients with an underlying cardiocirculatory disease amenable to immediate corrective intervention (angioplasty, surgery, transplantation).

Percutaneous Cardiopulmonary Support Aids Resuscitation From Sustained Ventricular Tachycardia

A 67-year-old man was transferred to hospital because of acute circulatory failure resulting from sustained left ventricular tachycardia (LVT) and dysfunction. Transthoracic echocardiography revealed severely impaired left ventricular contraction and dyskinesis of the apical wall. Neither anti-arrhythmic agents nor direct current cardioversion was effective; the patient was resuscitated by immediate use of percutaneous cardiopulmonary support and intraaortic balloon counterpulsation. Ventricular contraction returned to normal following restoration of normal sinus rhythm with amiodarone and cibenzoline. The pathogenesis of LVT accompanied by transient ventricular dyskinesis is discussed with regard to the efficient use of a mechanical circulatory support system in resuscitation.

Percutaneous cardiopulmonary bypass for cardiac emergencies

Percutaneous cardiopulmonary support systems (PCPS) are compact, battery-powered, portable heart-lung machines that can be implemented rapidly in any area of the hospital using thin-walled cannulae inserted via the femoral vessels. PCPS provides temporary circulatory support by actively aspirating blood from the patient's venous system using a centrifugal pump and hollow fiber membrane oxygenator for gas exchange. A review of clinical reports has delineated several indications for emergent applications, with the most frequent being cardiac arrest (CA) or cardiogenic shock (CS). Survival is more likely in patients with CS (40%) compared to CA (21%). Implementation of PCPS after unwitnessed CA or cardiopulmonary resuscitation > 30 min yields a patient survival rate of < 10%. The likelihood of patient survival after emergent PCPS is most often related to the patient undergoing a definitive anatomic surgical repair such as coronary artery bypass or pulmonary embolectomy. If the need for circulatory support extends beyond 6 h, conversion to conventional long-term extracorporeal membrane oxygenation or a ventricular assist device is recommended.

Percutaneous cardiopulmonary support as a bridge to emergency operation--two surviving cases

Two patients had percutaneous cardiopulmonary support (PCPS) used as a bridge to emergency surgery. A 66-year-old man admitted with profound cardiogenic shock underwent direct stenting under PCPS with the diagnosis of acute myocardial infarction of the left main trunk, with the intention of performing revascularization as soon as possible. Subsequently, double coronary artery bypass grafting was successfully accomplished. A 69-year-old woman, admitted with acute heart failure due to critical aortic stenosis, manifested cardiogenic shock while undergoing catheterization. PCPS was immediately instituted until the acute deterioration of her hemodynamic state could be reversed, and was continued uneventfully till aortic valve replacement was performed. These results suggest that the current PCPS system is an effective response to acute circulatory collapse and will contributed to the improved survival of patients.

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.