Use of the intra-aortic balloon pump after valve replacement

[Intraaortic Ballon-pump: Physiology, Indication, Management]

The intraaortic ballon-pump (IABP) is a percutaneous mechanical circulatory support device, which is used in patients either with insufficient cardiac output or in patients with high-risk situation before cardiac intervention, like surgical revascularisation or percutaneous coronary intervention (PCI). Due to electrocardiographic or arterial pressure pulse the IABP augments diastolic coronary perfusion pressure and reduces systolic afterload. Thereby, myocardial oxygen supply-demand ratio is improved and cardiac output is increased. Many national and international cardiology, cardiothoracic and intensive care medicine societies and associations worked together in order to develop evidence-based recommendations and guidelines for the preoperative, intraoperative and postoperative management of the IABP. This manuscript is mainly based on the S3 guideline "Use of intraaortic balloon-pump in cardiac surgery" from the German Society for Thoracic and Cardiovascular Surgery (DGTHG).

A New Method of Mechanical Circulatory Support with an Implantable Multichamber Pump System (IMPS): Presentation and First Experimental Results

This paper presents a new cardiac support device for left ventricular failure which consists of two inflatable bellows positioned dorsally and ventrally to the left ventricle. The implantable multichamber pump system (IMPS) is driven by a pneumatic pump system and controlled by a microcomputer using ECG-trigger and pacemaker modules. It was implanted via thoracotomy in 8 pigs. The circulatory parameters were measured in the animals on β-blockers, with cardiac failure and in ventricular fibrillation with an activated (IMPS on) and deactivated (IMPS off) system.

IMPS significantly increased the left ventricular pressure (LVPsys IMPS off: 63 ∓ 6 mmHg vs IMPS on: 96 ∓ 8 mmHg) and the blood pressure in the common carotid artery (Bpca' IMPS off: 69/38 mmHg vs IMPS on: 95/40 mmHg).

The IMPS proved to be highly efficient in the therapy of animals with acute cardiac failure and in ventricular fibrillation in the experimental model. Apart from its efficiency the advantages with this system are the ease of handling and its high biocompatibility due to the lack of contact with circulating blood.

Mortality in Open Heart Surgery with Intraaortic Balloon Pump Support

Mechanical circulatory assistance is frequently needed to support the failing heart. The aim of this study was to determine perioperative prognostic factors for hospital mortality in patients undergoing open heart surgery who required intraaortic balloon pump support. Between January 2002 and September 2006, 475 patients received an intraaortic balloon pump perioperatively. Hospital mortality was 21.89%. Risk factors for hospital death identified by multivariate logistic regression analysis were peripheral vascular disease, left main coronary artery disease, postoperative renal failure, postoperative cardiac arrest, and prolonged hospital stay. Minor and major intraaortic balloon pump-related complications were not significant in univariate and multivariate analysis; the incidence was 5.05%. It is suggested that the threshold for using balloon pump support is decreased in high-risk patients undergoing cardiac surgery.

Adverse 30-Day Outcomes After Cardiac Surgery: Predictive Role of Intraoperative Myocardial Acidosis

BACKGROUND

Regional myocardial acidosis in patients undergoing cardiac surgery has been shown to be reflective of regional myocardial ischemia. This study elucidates the relationship between intraoperative regional myocardial acidosis and 30-day postoperative outcomes after cardiac surgery.

METHODS

Intramyocardial tissue pH in the anterior and posterior left ventricular walls was measured in 397 adult patients undergoing valve replacement or coronary revascularization surgery between 1987 and 2001. Dedicated nurses and research assistants prospectively collected preoperative, intraoperative, and outcomes data. Regional myocardial acidosis was defined in terms of pH thresholds identified by recursive partitioning. Adverse 30-day outcome, defined as death or any one of six complications, was the dependent variable in a multivariate logistic regression analysis. A morbidity score was developed on the basis of the sensitivity of each of the six complications in predicting death, and was the dependent variable in a multivariate linear regression analysis.

RESULTS

During the period of aortic clamping, a mean intramyocardial tissue pH less than 6.85 was identified to be significant by recursive partitioning, and was encountered in either the anterior or posterior left ventricular wall in 85.4% of patients. After adjusting for preoperative and intraoperative variables, this pH threshold was found to be significantly associated with increased adverse outcomes within 30 days after surgery (p = 0.045). It was also significantly associated with increase in the morbidity score (p = 0.05).

CONCLUSIONS

Regional myocardial acidosis of a magnitude frequently encountered during aortic clamping is an independent determinant of adverse 30-day outcomes after cardiac surgery. Its reversal by pH-guided myocardial management has the potential of improving postoperative patient outcomes.

Beating-heart valvular surgery: a possible alternative for patients with severely compromised ventricular function

Cardioplegic arrest of the severely compromised ventricle may make weaning from cardiopulmonary bypass problematic. We report a novel approach to myocardial protection in a patient requiring multi-valve surgery who had an ejection fraction of 15%. Warm oxygenated blood was infused continuously both antegrade and retrograde during aortic valve replacement and mitral and tricuspid valve repair. Adequacy of perfusion was confirmed by the absence of electrocardiographic changes. Clinical improvement suggests that this strategy of myocardial protection warrants further investigation.

Extracorporeal membrane oxygenation support for adult postcardiotomy cardiogenic shock

BACKGROUND

Postcardiotomy cardiogenic shock occasionally develops in patients who have undergone cardiac procedures. We report our experience using extracorporeal membrane oxygenation (ECMO) in adult patients with postcardiotomy cardiogenic shock, and analyze the factors that affected outcomes for these ECMO patients.

METHODS

We retrospectively reviewed the medical records of ECMO patients.

RESULTS

From August 1994 to May 2000, 76 adult patients (48 men, 28 women; mean age, 56.8+/-15.9 years) received ECMO support for postcardiotomy cardiogenic shock at the National Taiwan University Hospital. The mean ECMO blood flow was 2.53+/-0.84 L/min. The cardiac operations included coronary artery bypass grafting (n = 37), coronary artery bypass grafting and valvular operation (n = 6), valvular operation alone (n = 14), heart transplantation (n = 12), correction of congenital heart defects (n = 3), implantation of a left ventricular assist device (n = 2), and aortic operations (n = 2). Fifty-four patients received ECMO support after intraaortic balloon pumping, but 22 patients directly received ECMO support. Two patients were bridged to heart transplantation and two bridged to ventricular assist devices. Thirty patients died on ECMO support. The causes of mortality included brain death (n = 3), refractory arrhythmia (n = 2), near motionless heart (n = 2), acute graft rejection (n = 1), primary graft failure (n = 1), uncontrolled bleeding (n = 5), and multiple organ failure (n = 16). Twenty-two patients were weaned off ECMO support but presented intrahospital mortality. The cause of mortality included brain death (n = 1), sudden death (n = 4), and multiple organ failure (n = 17). Twenty patients were weaned off ECMO support and survived to hospital discharge. During the follow-up of 33+/-22 months, all were in New York Heart Association functional status I or II except two cases of late deaths. Among the ECMO-weaned patients, "dialysis for acute renal failure" was a significant factor in reducing the chance of survival.

CONCLUSIONS

The ECMO provided a satisfactory partial cardiopulmonary support to patients with postcardiotomy cardiogenic shock, and allowed time for clinicians to assess the patients and make appropriate decisions.

Acute and temporary ventricular support with BioMedicus centrifugal pump

BACKGROUND

Short-term ventricular and pulmonary support can be provided by the Medtronic BioMedicus (Eden Prairie, MN) centrifugal pump, which is available in most cardiovascular surgery centers. This versatile pump can provide support during cardiopulmonary resuscitation, cardiopulmonary bypass, extracorporeal membrane oxygenation, and ventricular assistance. A common use of the pump is to provide ventricular assistance for patients after cardiotomy or cardiogenic shock.

METHODS

From January 1986 to September 1995, 141 patients at The Methodist Hospital in Houston, Texas were placed on the BioMedicus centrifugal pump after postcardiotomy cardiac failure. Patient treatment and postimplant complications are discussed.

RESULTS

Fifty-four percent of the patients were weaned; however, only 22% survived to discharge. There was a very high mortality rate in the early stage after support was discontinued, after weaning, and after device removal.

CONCLUSIONS

A high incidence of complications and death is likely related to the period of attempted weaning from cardiopulmonary bypass before the initiation of ventricular support. When weaning a patient from the pump during cardiopulmonary bypass or during ventricular assistance, it is important to optimize preload, after-load, ventricular function, and cardiac rhythm. In patients who have had postcardiotomy support, avoiding fluid overload, low colloid oncotic pressure, hypoperfusion, and use of excessive inotropic and vasoactive medications improve results.

Intraaortic balloon pump in open heart operations: 10-year follow-up with risk analysis

BACKGROUND

The intraaortic balloon pump (IABP) is the primary mechanical device used for perioperative cardiac failure.

METHODS

We analyzed the prognostic predictors and long-term survival of 344 patients undergoing cardiac operations who required the perioperative use of an IABP at our institution from January 1980 to December 1989. Hospital survivors (163 patients) were followed up for a mean of 7.45 years (range, 1 month to 15.3 years); cumulative follow-up included 1,167 patient-years.

RESULTS

The early mortality rate was 52.6% (181 patients). From parameters available at the time of IABP insertion, logistic regression analysis identified preoperative serum creatinine level, left ventricular ejection fraction, perioperative myocardial infarction, timing of IABP insertion, and indication for operation as independent predictors of early (30-day) death (p < 0.05). Cox regression analysis of hospital survivors identified timing of IABP insertion, perfusion time, and preoperative serum creatinine level as independent prognostic factors for late death (p < 0.05), whereas patient age was only marginally significant (p < 0.06). There was no association between IABP-related complications and death. Survival analysis demonstrated a 10-year actual survival rate of 22.04% +/- 0.023%, with 57 patients still at risk and significantly improved survival among those who received an IABP before operation (p < 0.02).

CONCLUSIONS

The early mortality rate in patients who received an IABP was high. Hospital survivors had a relatively good long-term prognosis. The significantly better short- and long-term survival of patients who received an IABP before operation may justify more liberal preoperative use of the IABP in high-risk patients.

Improved results for postcardiotomy cardiogenic shock with the use of implantable left ventricular assist devices

BACKGROUND

Over the past decade, the use of mechanical circulatory support in patients with postcardiotomy cardiogenic shock has resulted in hospital discharge rates of 25% to 40%. In an attempt to improve patient survival, we initiated a program of early insertion of an implantable Thermocardiosystems Incorporated Heartmate left ventricular assist device in patients who have circulatory failure after having undergone high-risk cardiac operations.

METHODS

Between April 1993 and February 1997, 12 patients underwent insertion of an implantable left ventricular assist device for postcardiotomy cardiogenic shock after coronary artery bypass grafting. Indications for insertion included postoperative cardiogenic shock (7 patients), postoperative cardiac arrest (3 patients), and failure to wean from cardiopulmonary bypass (2 patients).

RESULTS

The median time to device insertion was 3.5 days. The mean duration of left ventricular assist device support was 103 +/- 19 days (range, 2 to 225 days). Nine of 11 patients (82%) survived to undergo either transplantation (8 patients) or explantation (1 patient), with successful hospital discharge of all 9 patients. The major complication was device-related infection (42%). A single thromboembolism occurred in a patient with an infection.

CONCLUSIONS

Long-term outcome after postcardiotomy cardiogenic shock is improved substantially with the use of an implantable left ventricular assist device early in the postoperative course. Access to such a device is an important consideration before undertaking a high-risk cardiac operation, and early implantation of the device is a critical factor in ensuring long-term survival.

Successful application of hypothermia combined with intra-aortic balloon pump support to low-cardiac-output state after open heart surgery

The authors report a successful application of hypothermia, along with intra-aortic balloon pump (IABP) support, to postcardiotomy ventricular failure. Surface-cooling hypothermia was applied in 8 patients after open heart surgery. The original cardiac procedure consisted of 3 aortocoronary bypass graftings (ACBGs), 2 aortic valve replacements (AVRs), 1 repair for left ventricular (LV) rupture after mitral valve replacement (MVR), 1 MVR + ACBG, and 1 MVR + AVR + tricuspid valve annuloplasty (TAP). Their ages ranged from fifty-two to sixty-eight years with a mean of sixty-one years. Hemodynamic criteria for induction of hypothermia included cardiac index (CI) less than 2.0 L/min/m2 with left atrial pressure greater than 18 mmHg despite the use of IABP and maximum pharmacologic support. Blood temperature was maintained at around 33 degrees C. By six hours after induction of hypothermia the tissue oxygen consumption decreased significantly with no hemodynamic deterioration as compared with that before cooling. The duration of hypothermia ranged from thirty-six to one hundred fifty-nine hours with a mean of seventy-eight hours. All 8 patients finally discontinued IABP support with a mean driving time of one hundred thirty-two hours. Five of them were ultimately discharged from the hospital and returned to their previous life-style. The authors believe that, from the perspective of monetary and personal resources, the use of hypothermia with IABP support could be a therapeutic option for patients with postcardiotomy ventricular failure.

Extracorporeal membrane oxygenation for postcardiotomy cardiogenic shock

BACKGROUND

Extracorporeal membrane oxygenation circuits have recently been introduced for extracorporeal life support (ECLS) in adult patients in cardiogenic shock and have been shown to provide excellent oxygenation and hemodynamic support. Heparin coating of the extracorporeal circuit provides a more biocompatible surface, which has been shown to minimize early surface-induced complement activation and platelet dysfunction and hence may improve patient survival. This report reviews our experience with extracorporeal membrane oxygenation to treat postcardiotomy cardiogenic shock using minimal to no systemic heparinization in 23 patients.

METHODS

During the 22-month period September 1992 through July 1994, 23 patients in cardiogenic shock were placed on venoarterial ECLS using a heparin-bonded circuit. These patients' charts were retrospectively reviewed. A logistic regression analysis of the variables collected was performed to identify clear-cut predictors of ability to be weaned from ECLS.

RESULTS

Average patient age was 47.3 +/- 16.4 years (range, 5 to 72 years). There were 17 male patients. Average time on ECLS was 58.4 +/- 35.1 hours (range, 0.5 to 144 hours). Statistical analysis revealed that patients unable to be weaned from ECLS were more likely to have a critically dilated left ventricle on echocardiography and were female. Ten patients (43.5%) died while on ECLS. Four patients were transferred to an implantable left ventricular assist device, and 3 underwent successful transplantation. The 9 other patients were successfully weaned from ECLS, and 4 were discharged home from the hospital. Overall, 7 patients (30.4%) who were placed on ECLS were successfully discharged home.

CONCLUSIONS

Extracorporeal life support using an extracorporeal membrane oxygenation system provides excellent cardiac support with similar hospital survival rates as centrifugal mechanical support. Extracorporeal life support has complications unique to itself, but with time, these are likely to be overcome. Women and patients with persistent left ventricular dilatation are less likely to be weaned.

Bio-Medicus centrifugal ventricular support for postcardiotomy cardiac failure: a review of 129 cases

BACKGROUND

Bio-Medicus centrifugal ventricular support has been used widely for postcardiotomy cardiac failure. The purpose of this study was to review a large series of support patients examining complications and outcomes.

METHODS

One hundred twenty-nine patients undergoing cardiac operations at The Methodist Hospital in Houston, Texas, were placed on Bio-Medicus centrifugal ventricular support for postcardiotomy cardiac failure; 102 were male and 27 were female with a mean age of 61.6 years. These patients were selected for ventricular support based solely on failure to be weaned from cardiopulmonary bypass or progressive postcardiotomy cardiac failure shortly after arrival in the intensive care unit.

RESULTS

These patients experienced numerous complications including coagulopathy, renal insufficiency or failure, sepsis, neurologic deficits, ventricular failure, arrhythmias, and death; 56.3% of patients were weaned from mechanical support and 21.0% were discharged alive. Causes of death included ventricular failure (62.4%), arrhythmias (12.9%), triage (6.9%), perioperative myocardial infarction or cardiac arrest (5.0%), coagulopathy (4.0%), sepsis syndrome (4.0%), cardiac graft failure (3.0%), and device related (1.0%). The one device-related death was a venous cannula dislodgment in the intensive care unit with subsequent exsanguination. Device-related complications were seen in only 1.6% of patients.

CONCLUSIONS

Bio-Medicus centrifugal ventricular support can be implemented rapidly and relatively easily. There are few device-related complications and the cost is relatively inexpensive compared with other assist systems. This series demonstrates that a substantial number of patients who experience reversible postcardiotomy myocardial injury will benefit from temporary centrifugal ventricular support.

Vascular complications from intraaortic balloons: risk analysis

PURPOSE

The purpose of this study was to assess the incidence of and predictors for vascular complications in patients who required perioperative intraaortic balloon pump (IABP) support.

METHODS

Data from 580 patients collected with a retrospective review were statistically analyzed with 25 perioperative parameters, and significant variables were evaluated with multivariate analysis. These data were also statistically compared with data from a 1983 study from our institution.

RESULTS

Vascular complications occurred in 72 patients (12.4%). The three aortic perforations were fatal. Ipsilateral leg ischemia occurred in 69 patients. Of these, ischemia was resolved in 82% of patients by IABP removal (21), thrombectomy (21), vascular repair (13), fasciotomy (2), or without intervention (2). Six patients died with the intraaortic balloon in place. Four patients required amputation for ischemia, but all survived.

CONCLUSIONS

Vascular complications were not predictive of operative death (p = 0.26). Risk analyses with 25 perioperative parameters revealed that history of peripheral vascular disease, female sex, history of smoking, and postoperative insertion were independent predictors of vascular complications. However, most risk for vascular complications cannot be explained by these factors because of a low R2 value. Compared with the results of our 1983 study, the incidence of IABP-related complications has not changed, but the severity of complications has decreased significantly, and IABP-induced death has decreased significantly.

A model to predict survival at time of postcardiotomy intraaortic balloon pump insertion

To facilitate timely application of new forms of cardiac support to patients at highest risk after cardiotomy despite conventional support with the intraaortic balloon pump, an accurate prediction of survival must be available at the time of weaning from cardiopulmonary bypass. We, therefore, acquired 240 demographic, disease, and perioperative characteristics of 322 patients (mortality rate, 48.4%) who required IABP support to separate from bypass. Four variables available before or within 10 minutes of the first attempt at weaning from bypass significantly predicted mortality by stepwise logistic regression: complete heart block as demonstrated by need for temporary pacing at weaning (p < 0.001), advanced age (p < 0.002), preoperative blood urea nitrogen concentration (p = 0.036), and female sex (p = 0.048). An equation generated by the logistic model predicted a 72.2% survival rate in the 25% of patients at least risk (actual survival rate, 71.6%); in the 25% at greatest risk, death was predicted in 73.0%, and the actual mortality rate was 74.1%. The equation was then prospectively applied to 330 intraaortic balloon pump-supported patients managed at another institution. The overall mortality rate there was 41.2%; in the 25% at least risk, predicted survival rate was 70.5% (actual survival rate, 77.1%), and in the 25% at greatest risk, predicted mortality rate was 75.7% (actual mortality rate, 62.7%). Thus, retrospectively at one institution and prospectively at another, the equation generated by this model based only on data available at the time of weaning from bypass was able to define one subgroup of patients 2.6 to 2.7 times as likely to die as another subgroup from within similar cohorts.(ABSTRACT TRUNCATED AT 250 WORDS)

Total parenteral nutrition in patients with intra-aortic balloon counterpulsation

The effects of total parenteral nutrition (TPN) were studied in nine of 19 patients with intra-aortic balloon pumping TPN (c. 27 kcal/kg/day) was begun 3 hours after the start of pumping. The non-protein caloric source was composed of hypertonic dextrose and fat emulsion (60% and 40%). The nitrogen intake was 1 g/150-200 kcal/day. The ten control patients received 5% dextrose in corresponding volume/hour. Hemodynamic studies were performed before and 24, 48 and 72 hours after the start of counterpulsation. The predicted and the observed resting energy expenditure were recorded in both patient groups during counter-pulsation. Systemic and pulmonary vascular resistance differed significantly between the groups. Cardiac function improved in both groups. In the TPN group the measured resting energy expenditure increased by 33% more than predicted on day 2 and by 56% on day 3 and in the controls the figures were 31% and 40%--all rises significant. Total parenteral nutrition with low fat content thus alters the hemodynamic equilibrium without clinically significant effects in patients undergoing intra-aortic balloon pumping. These patients are hypermetabolic and should receive artificial nutrition as soon as possible.

Intraaortic balloon counterpulsation: patterns of usage and outcome in cardiac surgery patients

Between January 1, 1986, and May 6, 1991, 7,884 cardiac surgical procedures requiring cardiopulmonary bypass were performed at our institution, including 672 (9.8% of adult procedures) performed in 669 patients that were associated with preoperative (n = 240), intraoperative (n = 353), or postoperative (n = 79) use of an intraaortic balloon pump. The mean age of recipients was 65.3 years (range, 16 to 89 years). Intraaortic balloon pump usage increased during the study period from 6.4% of patients (83/1,298) in 1986 to 12.7% of patients (169/1,333) in 1990. The relative distribution between preoperative (mean, 35.7%), intraoperative (52.5%), and postoperative (11.8%) insertion remained nearly constant during the study period. The overall operative (30-day) mortality for patients with preoperative, intraoperative, or postoperative insertion of the intraaortic balloon pump was 19.6%, 32.3%, and 40.5%, respectively (X2 = 16.4; p less than 0.001). Although use of the intraaortic balloon pump in the intraoperative and postoperative settings is accompanied by a favorable outcome in most patients, the high associated mortality suggests the need for earlier use of the intraaortic balloon pump or other supportive measures such as the ventricular assist device.

Intra-aortic counterpulsation balloon pumps: CT appearance

Intra-aortic counterpulsation balloon pumps (ICBP) used in the setting of cardiogenic shock or high risk cardiac surgery, have been identified on chest films in the inflated state during diastole (1). We report characteristic computed tomography (CT) findings of an inflated ICBP, discuss its radiographically identified complications, and suggest that the presence of this device should be excluded before suspecting other etiologies for intra-aortic gas.

Operative intra-aortic balloon rupture

Rupture of an intra-aortic balloon (IAB), inserted to assist in weaning from cardiopulmonary bypass, occurred during attempted intra-aortic administration of protamine in a 71-year-old male who later died. Intra-aortic balloon counterpulsation (IABC) is most commonly utilized to assist in weaning from cardiopulmonary bypass (CPB) or to augment low-flow states following CPB. In-hospital survival following IAB insertion in these circumstances in patients with coronary artery disease is approximately 60 per cent. Patients with valvular disease have a lower in-hospital survival rate (50 per cent). Complications of IABC are usually of vascular or infectious origin. Balloon rupture is a rare though potentially lethal complication. The effects of balloon rupture may be compounded by the use of helium as a driving gas to inflate the balloon. Intra-aortic administration of protamine has not been shown to be superior to peripheral administration and should be avoided if an IAB is in place.