Abstracts & Publications

JACC 2008;52:1584-8

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IABP delivers comparable hemodynamic support to the Impella 2.5.

INTRODUCTION: The objective of this study was to determine if Impella 2.5 provides superior hemodynamic support compared with the IABP in cardiogenic shock patients.

METHOD: A prospective, randomized study on 26 patients with cardiogenic shock.

• Primary end point was the change of the cardiac index from baseline to 30 min after implantation.
• Secondary end points included lactic acidosis, hemolysis, and mortality after 30 days.

RESULTS:

•   Impella IABP
• CI at Baseline 1.7 l/min/m2 1.7 l/min/m2
• CI at 4 hours 2.23 l/min/m2 2.25 l/min/m2
• SVR at Baseline (dyns-s-cm-5) 1,617 1,546
• SVR after Implantation 1,457 1,333
• PCWP at Baseline (mm Hg) 22 22
• PCWP after Implantation 19 20
• LVEF at Baseline 27% 28%
• LVEF at Discharge 35% 45%
• 30-day Mortality 46% 46%

DISCUSSION:

• Reversal of serum lactate levels were comparable for both groups
• Hemolysis was significantly higher in Impella patients
• Impella delays treatment with extended insertion times
• Impella patients required more packed red blood cells and fresh-frozen plasma, while one patient suffered from acute limb ischemia requiring surgery

Abstract - E P Tsagalou, et al. CHF 2009;15:35-40

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Intractable heart failure (HF) remains a leading fatal complication of acute myocardial infarction (AMI). Intra-aortic balloon pump (IABP) counterpulsation assists the failing left ventricle and accelerates the functional recovery of stunned myocardium. Despite its remarkable performance, the beneficial effects of the IABP in the setting of acute HF or cardiogenic shock complicating AMI have not been confirmed in a randomized clinical trial. Instead, large amounts of information have been collected in observational studies or in retrospective analyses of randomized trials of reperfusion strategies in patients with AMI. The strategy of "stabilize with IABP, treat with reperfusion, and transfer for complete revascularization" has, thus far, yielded the best outcomes, and every effort should be made to implement this strategy in all patients presenting with AMI and severe HF.

Abstract - M Seyfarth, et al. JACC 2008;52:1584-8

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OBJECTIVES: The aim of this study was to test whether the left ventricular assist device (LVAD) Impella LP2.5 (Abiomed Europe GmbH, Aachen, Germany) provides superior hemodynamic support compared with the intra-aortic balloon pump (IABP).

BACKGROUND: Cardiogenic shock caused by left ventricular failure is associated with high mortality in patients with acute myocardial infarction (AMI). An LVAD may help to bridge patients to recovery from left ventricular failure.

METHODS: In a prospective, randomized study, 26 patients with cardiogenic shock were studied. The primary end point was the change of the cardiac index (CI) from baseline. Secondary end points included lactic acidosis, hemolysis, and mortality after 30 days.

RESULTS: Baseline cardiac index (CI) was 1.7 l/min/m2 for both groups. At 4 hours CI was higher with IABP (2.23 l/min) vs. IABP (2.25 l/min). Reversal of serum lactate levels were comparable for both groups. Hemolysis, as measured by free hemoglobin, was significantly higher in Impella patients during the first 24 hours. The Impella patients also required more packed red blood cells and fresh-frozen plasma, while one patient suffered from acute limb ischemia requiring surgery.Overall 30 day mortality was 46% in both groups.

Abstract - H Thiele, et al. EHJ 2007;28:2057-2063

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Cardiogenic shock (CS) remains the most common cause of death in patients with acute myocardial infarction (AMI). In addition to percutaneous coronary intervention, inotropes, and fluids, intraaortic balloon pumping (IABP) is most widely used for initial haemodynamic stabilization. However, the main limitation of IABP is the lack of active circulatory support and the requirement of a certain level of left ventricular (LV) function. In many patients with severe depression of LV function, haemodynamic support and LV unloading derived from IABP is insufficient to reverse CS. The use of percutaneous LV assist devices (LVAD) with active circulatory support might be beneficial in CS patients not responding to standard treatment including IABP support. This review reports the current experience of percutaneous LVAD in CS complicating AMI.

Am J Card 2010;105:967-971

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INTRODUCTION: Comparison of Hospital Mortality With Intra-Aortic Balloon Counterpulsation Insertion Before Versus After Primary Percutaneous Coronary Intervention for Cardiogenic Shock Complicating Acute Myocardial Infarction

• Single Center, Retrospective Study
• 48 Patients with AMI complicated by cardiogenic shock
• No significant differences in baseline clinical characteristics

METHOD:

• All patients were given intravenous aspirin & clopidogrel
• 26 Patients treated with IABC before primary PCI
• 22 Patients treated with IABC after primary PCI

RESULTS: Multivariate analysis identified renal failure and insertion of the IABP after PCI as the only independent predictors of in-hospital mortality.

•  
    IABP Before PCI
  (n=26) IABP After PCI
  (n=22) P Value
• In-hospital Death 5 (19%) 13 (59%) 0.007
• MAACE 6 (23%) 17 (77%) 0.0004

DISCUSSION: The principle finding of the present analysis was that LV unloading using IABP during primary PCI resulted in a significant reduction in in-hospital mortality.

Mechanical unloading of the ventricle using IABP during ischemia and reperfusion probably results in significant myocardial salvage compared to reperfusion alone. Possible mechanisms include a reduction in myocardial oxygen demand, an increase in coronary artery blood flow and reduced microvascular obstruction, leading to a reduction in infarct expansion after reperfusion.

Christenson JT; Badel P; Simonet F; Schmuziger M, Preoperative intraaortic balloon pump enhances cardiac performance and improves the outcome of redo CABG. Ann Thorac Surg, 1997 Nov, 64:5, 1237-44

BACKGROUND: Reoperative coronary artery bypass grafting (redo CABG) is associated with an increased operative risk compared with primary CABG. Because the hospital mortality in redo CABG is known to be influenced by poor left ventricular function (left ventricular ejection fraction < or = 0.40), unstable angina, and left main stem stenosis greater than or equal to 70%, a preoperative intraaortic balloon pump (IABP) support could be beneficial to improve the outcome in high-risk redo CABG.

METHODS: Between June 1994 and October 1996, 48 high-risk patients underwent redo CABG and were randomized into the following groups: group 1 (24 patients) who received preoperative IABP treatment on average 2 hours before cardiopulmonary bypass, and group 2 (24 patients) who received no preoperative IABP and served as controls. Mean age was 65 years and 90% (43 patients) were men. Forty-one patients had preoperative left ventricular ejection fraction less than or equal to 0.40 (85%), 38% (18 patients) had left main stem stenosis greater than or equal to 70%, and 54% (26 patients) had unstable angina preoperatively. Preoperative patient characteristics did not differ between the groups.

RESULTS: The time on cardiopulmonary bypass was shorter in group 1, 86 versus 110 minutes (p = 0.006). There were no hospital deaths in group 1, but four deaths occurred in the control group (p = 0.049). Cardiac index rose significantly preoperatively after introduction of the IABP in group 1. Cardiac index was significantly higher postoperatively in group 1 compared with group 2 and remained significantly higher during the first 24 hours after cardiopulmonary bypass. Significantly fewer patients in the IABP group had postoperative low cardiac output (4 versus 13 patients). Nine patients in group 2 required IABP support postoperatively for 4.1 +/- 1.7 days. Only 2 patients in group 1 needed IABP postoperatively, and their IABPs were successfully removed on the first postoperative day. The preoperative IABP-supported patients had a shorter intensive care unit stay, 2.4 +/- 0.8 days compared with group 2, 4.5 +/- 2.2 days (p = 0.007), as well as a shorter hospital stay. The preoperative IABP treatment was found to be cost-effective.

CONCLUSIONS: Preoperative treatment with IABP in high-risk redo CABG patients is an effective modality to prepare these patients to have their myocardial revascularization in an as nonischemic situation as possible, which resulted in a significantly lower hospital mortality, fewer instances of postoperative low cardiac output, and shorter stays in both the intensive care unit and the hospital.

Dietl CA; Berkheimer MD; Woods EL; Gilbert CL; Pharr WF; Benoit CH, Efficacy and cost-effectiveness of preoperative IABP in patients with ejection fraction of 0.25 or less. Ann Thorac Surg, 1996 Aug, 62:2, 401-8; discussion 408-9

BACKGROUND:The purposes of this study are to determine whether patients with severe left ventricular dysfunction benefit from prophylactic insertion of an intraaortic balloon pump and to evaluate its cost-effectiveness.

METHODS:Between January 1991 and December 1995, 163 consecutive patients with a left ventricular ejection fraction of 0.25 or less underwent isolated coronary artery bypass grafting. An intraaortic balloon pump was inserted before operation in 37 patients (group A). The remaining 126 patients underwent operation without preoperative insertion of the device (group B). Preoperatively, 91.9% (34/37) of group A patients and 54.8% (69/126) of group B patients were in New York Heart Association functional class III or IV (p < 0.001).

RESULTS:The 30-day mortality rate was 2.7% (1/37) and 11.9% (15/126) for groups A and B, respectively (p < 0.005). All deaths occurred in patients in functional class III or IV. In group B, 28 patients (22.2%) required an intraaortic balloon pump after cardiotomy for low cardiac output, 42.9% (12/28) of whom died. Median postoperative hospital stay was 9.9 days and 12.0 days, and mean hospital charges were $50,627 and $54,818 for survivors in groups A and B; respectively (p = not significant).

CONCLUSIONS:Our experience suggests that patients with severe left ventricular dysfunction undergoing coronary artery bypass grafting may benefit from preoperative intraaortic balloon pump insertion, especially patients in functional class III or IV. This approach improved survival significantly, reduced hospital stay, and was more cost-effective.

Ingram JM, Innovations in intra-aortic balloon pump management: Computer modem technology, J Extra-Corporeal Technology 1994;26(3):135-139

The computer modem technology being developed by Datascope Corp. for the purpose of off-site intra-aortic balloon pump (IABP) monitoring was clinically evaluated in 30 patients requiring IABP support. The Datascope System 95 model IABP with built-in modem was used on all patients. Remote communications via a personal computer with modem were conducted under both routine and emergency settings. The Datascope PC IABP software was evaluated for its user compatibility, efficiency, diagnostic capability and overall usefulness as a clinical tool. During the eight month evaluation period, 87 remote communications were conducted for both routine and emergency IABP evaluation checks. Adjustments were recommended on 22 occasions relevant to balloon timing, trigger mode selection and augmentation volume settings. Eight communications were initiated in emergency settings due to a variety of patient conditions. Emergency intervention was successful in diagnosing and resolving critical situations including atrial arrhythmias, pacemaker timing, low cardiac output syndrome, loss of trigger source, catheter malpositioning and poor augmentation. The diagnostic capabilities and efficient means of data collection by the computer software provide the clinician with a valuable tool for routine IABP clinical monitoring, as well as emergency problem resolution.

Kovack PJ; Rasak MA; Bates ER; Ohman EM; Stomel RJ, Thrombolysis plus aortic counterpulsation: improved survival in patients who present to community hospitals with cardiogenic shock. J Am Coll Cardiol, 1997 Jun, 29:7, 1454-8

OBJECTIVE:We sought to explore the potential benefit of combining intraaortic balloon counterpulsation (IABP) with thrombolysis for acute myocardial infarction (MI) complicated by cardiogenic shock.

BACKGROUND:In community hospitals, this condition is usually managed with thrombolysis alone.

METHODS:We reviewed the charts of 335 patients from two community hospitals who presented with acute MI and had cardiogenic shock between 1985 and 1995. RESULTS: Of 46 patients who underwent thrombolysis within 12 h of acute infarction with confirmed cardiogenic shock, 27 underwent IABP and 19 did not. Age, systolic blood pressure with shock, pulmonary artery catheter use, pulmonary capillary wedge pressure and the incidence of diabetes mellitus and anterior MI did not differ between groups. Patients treated with IABP were somewhat more likely to have prior MI and had a significantly greater cardiac index (2.0 vs. 1.5 liters/min per m2, p = 0.04). Although no deaths occurred within 2 h of presentation, patients not treated with IABP tended to die earlier (6.8 +/- 5 vs. 23.8 +/- 19 h, p = 0.13). Patients treated with IABP had a significantly higher rate of community hospital survival (93% vs. 37%, p = 0.0002), and more of them were transferred for revascularization (85% vs. 37%). Of 30 patients transferred for revascularization, 27 underwent angioplasty or bypass surgery; hospital survival was 74%. Patients treated with IABP also had a significantly higher overall hospital and 1-year survival rate (67% vs. 32%, p = 0.019).

CONCLUSIONS:Survival may be enhanced and transfer for revascularization facilitated when community hospitals use both thrombolysis and IABP to treat patients with acute MI complicated by cardiogenic shock.

O'Murchu B; Foreman RD; Shaw RD; Brown DL; Peterson KL; Buchbinder M, Role of intraaortic balloon pump counterpulsation in high risk coronary rotational atherectomy, J Am Coll Cardiol 1995;26:1270-5

OBJECTIVE:This study sought to evaluate the role of intraaortic balloon pump counterpulsation in preventing hemodynamic instability and promoting a successful outcome during percutaneous transluminal coronary rotational atherectomy in high risk patients.

BACKGROUND:The application of rotational atherectomy has widened to include patients with complex lesions and left ventricular dysfunction. Although intraaortic balloon pumping has been successfully used to provide hemodynamic support during balloon angioplasty, its role in high risk rotational atherectomy has not yet been defined.

METHODS:In a retrospective review of 159 consecutive high risk patients who underwent rotational atherectomy, 28 had an intraaortic balloon pump placed electively before the procedure (Group 1) whereas 131 did not (Group 2). RESULTS. Group 1 was older and more likely to have multivessel disease and left ventricular dysfunction. Augmented diastolic pressure was maintained >90mmHg in all Group 1 patients, and significant procedure-related hypotension was encountered in nine Group 2 patients, requiring an emergency intraaortic balloon pump in five. Procedural success was achieved in all 28 patients in Group 1 and in 118 in Group 2 (p=0.07). Slow flow occurred in 18% and 17% of Group 1 and 2 patients, respectively. Among patients with slow flow, non-Q wave myocardial infarction occurred only in Group 2 (0% vs. 27%). On multivariate analysis, elective intraaortic balloon pump placement was the only variable to correlate with a successful procedure uncomplicated by hypotension (p<0.05). Hospital stay and vascular complications were similar in both groups.

CONCLUSIONS:Elective placement of an intraaortic balloon pump before coronary rotational atherectomy in selected high risk patients promotes both procedural hemodynamic stability and a successful outcome.

Ohman EM; George BS; White CJ; Kern MJ; Gurbel PA; Freedman RJ; Lundergan C; Hartmann JR; Talley JD; Frey MJ; et al, Use of aortic counterpulsation to improve sustained coronary artery patency during acute myocardial infarction. Results of a randomized trial. The Randomized IABP Study Group. Circulation, 1994 Aug, 90:2, 792-9

BACKGROUND:Aortic counterpulsation has been observed to reduce the rate of reocclusion of the infarct-related artery after patency has been restored during acute myocardial infarction in observational studies. To evaluate the benefit-to-risk ratio of aortic counterpulsation during the early phase of myocardial infarction, a multicenter randomized clinical trial was performed.

METHODS & RESULTS:Patients who had patency restored during acute cardiac catheterization within the first 24 hours of onset of myocardial infarction were randomly assigned to aortic counterpulsation for 48 hours versus standard care. Intravenous heparin was used similarly in both groups and was continued for a median (25th, 75th percentile) of 5 (2,7) days. A total of 182 patients were enrolled; 96 were assigned to aortic counterpulsation and 86 to standard care. Repeat cardiac catheterization was performed at a median of 5 (4,6) days after randomization in 89% of patients assigned to aortic counterpulsation and in 90% of control patients. Patients randomized to aortic counterpulsation had similar rates of severe bleeding complications (2% versus 1%), number of units of blood transfused (mean, 1.3 +/- 2.6 versus 0.9 +/- 1.8 units), and vascular repair or thrombectomy (5% versus 2%) compared with patients treated in a conventional manner. Patients randomized to aortic counterpulsation had significantly less reocclusion of the infarct-related artery during follow-up compared with control patients (8% versus 21%, P < .03). In addition, there was a significantly lower event rate in patients assigned to aortic counterpulsation in terms of a composite clinical end point (death, stroke, reinfarction, need for emergency revascularization with angioplasty or bypass surgery, or recurrent ischemia): 13% versus 24%, P < .04.

CONCLUSIONS:This randomized trial showed that careful use of prophylactic aortic counterpulsation can prevent reocclusion of the infarct-related artery and improve overall clinical outcome in patients undergoing acute cardiac catheterization during myocardial infarction.

Talley JD; Ohman EM; Mark DB; George BS; Leimberger JD; Berdan LG; Davidson Ray L; Rawert M; Lam LC; Phillips HR; Califf RM, Economic implications of the prophylactic use of intraaortic balloon counterpulsation in the setting of acute myocardial infarction. The Randomized IABP Study Group. Intraaortic Balloon Pump. Am J Cardiol 1997 Mar 79;5: 590-4

Intraaortic balloon counterpulsation (IABP) has been shown to improve coronary artery patency and reduce the rates of recurrent myocardial ischemia and its sequelae in selected patients when used within 24 hours of acute myocardial infarction. The economic implications of prophylactic IABP use are unknown. We obtained hospital bills for 102 patients enrolled in the Randomized IABP Trial (56%) and converted charges to costs using each hospital's Medicare cost report. In-hospital costs for patients who had 48 hours of IABP were compared with those of patients who did not. The costs of angiographic and clinical complications were determined. Small differences in clinical and angiographic characteristics existed between patients in the economic substudy and the overall population, but overall angiographic and clinical outcomes were comparable. Costs for patients who had IABP versus control patients were similar: mean $22,357 +/- $14,369 versus $19,211 +/- $8,414, median (25th and 75th percentiles) $17,903 ($15,787, $22,147) versus $17,913 ($15,144, $21,433), p = 0.45. Hospital costs were higher with the development of recurrent ischemia: mean $23,125 +/- $7,690 versus $20,416 +/- $12,449, median $21,069 ($17,896, $26,885) versus $17,492 ($14,892, $20,998) p = 0.02. Patients who had an adverse clinical event (death, stroke, reinfarction, and emergency revascularization) also had higher hospital costs: mean $25,598 +/- $10,024 versus $19,790 +/- $12,045, median $21,877 ($18,380, $28,049) versus $17,364 ($14,773, $20,779), p = 0.002. The prophylactic use of IABP in patients at high risk of infarct artery reocclusion within 24 hours of acute myocardial infarction provides sustained clinical benefit without substantially increasing hospital costs.

Jan T. Christenson, MD, PhD, François Simonet, MD, Pierre Badel, MD, and Martin Schmuziger, MD Optimal Timing of Preoperative Intraaortic Balloon Pump Support in High-Risk Coronary Patients Departments of Cardiovascular Surgery and Anesthesiology, Hôpital de la Tour, Meyrin-Geneva, Switzerland

BACKGROUND:Beneficial effects of preoperative intraaortic balloon pump (IABP) treatment, on outcome and cost, in high-risk patients who have coronary artery bypass grafting have been demonstrated. We conducted a prospective, randomized study to determine the optimal timing for preoperative IABP support in a cohort of high-risk patients.

METHODS:Sixty consecutive high-risk patients who had coronary artery bypass grafting (presenting with two or more of the following criteria: left ventricular ejection fraction less than 0.30, unstable angina, reoperation, or left main stenosis greater than 70%) entered the study. Thirty patients did not receive preoperative IABP (controls), 30 patients had preoperative IABP therapy starting 2 hours (T2), 12 hours (T12), or 24 hours (T24), by random assignment, before the operation. Fifty patients had preoperative left ventricular ejection fraction mean, less than 0.30 (less than 0.26 ± 0.08), (n=40) unstable angina, 28% (n=17) left main stenosis, and 32% (n=19) were reoperations.

RESULTS:Cardiopulmonary bypass was shorter in the IABP groups. There was one death in the IABP group and six in the control group. The complication rate for IABP was 8.3% (n=5) without group differences. Cardiac index was significantly higher postoperatively (p < 0.001) in patients with preoperative IABP treatment compared with controls. There were no significant differences between the three IABP subgroups at any time. The incidence of postoperative low cardiac output was significantly lower in the IABP groups (p < 0.001) Iintubation time, length of stay in the intensive care unit and the hospital was shorter in the IABP groups (p=0.211, p < 0.001, and p=0.002, respectively). There were no differences between the IABP subgroups in any of the studied variables.

CONCLUSIONS:The beneficial effect of preoperative IABP in high-risk patients who have coronary artery bypass grafting was confirmed. There were no differences in outcome between the subgroups; therefore, at 2 hours preoperatively, IABP therapy can be started. (Ann Thorac Surg 1999;68:934-9) ©1999 by The Society of Thoracic Surgeons

Brodie BR; Stuckey TD; Hansen C; Muncy D.; Intra-aortic balloon counterpulsation before primary percutaneous transluminal coronary angioplasty reduces catheterization laboratory events in high-risk patients with acute myocardial infarction. Am J Cardiol 1999 Jul 1;84(1):18-23

The benefit of intra-aortic balloon counterpulsation (IABC) before primary percutaneous transluminal coronary angioplasty (PTCA) for acute myocardial infarction in high-risk patients has not been well documented. Consecutive patients (n = 1,490) with acute myocardial infarction treated with primary PTCA from 1984 to 1997 were prospectively enrolled in an ongoing registry. Catheterization laboratory events occurred during or after intervention in 88 patients (5.9%), including ventricular fibrillation in 59 patients (4.0%), cardiopulmonary arrest in 46 patients (3.1%), and prolonged hypotension in 33 patients (2.2%). Cardiogenic shock was the strongest predictor of catheterization laboratory events (odds ratio [OR] 2.18, 95% confidence intervals [CI] 1.58 to 3.02) followed by low ejection fraction (<30%) (OR 1.51, 95% CI 1.06 to 2.15) and congestive heart failure (CHF) (OR 1.45, 95% CI 1.01 to 2.07). IABC used before intervention was associated with fewer catheterization laboratory events in patients with cardiogenic shock (n = 1 19) (14.5% vs. 35.1%, p = 0.009), in patients with CHF or low ejection fraction (n = 119) (0% vs. 14.6%, p = 0.10), and in all high-risk patients combined (n = 238) (1 1.5% vs. 21.9%, p = 0.05). IABC was a significant independent predictor of freedom from catheterization laboratory events (OR 0.48, 95% CI 0.29 to 0.79). These data support the use of IABC before primary PTCA for acute myocardial infarction in all patients with cardiogenic shock, and suggest that prophylactic IABC may also be beneficial in patients with CHF or depressed left ventricular function.

Rosen AB; Humphries JO; Muhlbaier LH; Kiefe CI; Kresowik T; Peterson ED.; Effect of clinical factors on length of stay after coronary artery bypass surgery: results of the cooperative cardiovascular project. Am Heart J 1999 Jul;138(1 Pt 1):69-77

BACKGROUND:Rising health care costs have prompted careful review of comparative hospital resource use. Length of stay after bypass surgery has received particular attention. However, many providers assert that these variations are caused by differences in the clinical mix of patients treated. Our goals were to identify the major clinical predictors of postoperative length of stay (PLOS) after coronary artery bypass graft surgery (CABG), document variations in PLOS among 28 hospitals, and assess the degree to which patient characteristics account for hospital variations in PLOS.

METHODS:Detailed clinical data on 3605 Medicare patients undergoing CABG in 28 Alabama and Iowa hospitals were analyzed by stepwise linear regression to identify significant clinical predictors of PLOS. Analysis of variance was used to compare hospitals' PLOS while controlling for significant patient risk factors. RESULTS: The mean age was 72.1 years, 34.7% were female, and the in-hospital mortality rate was 5.6%. The median and mean PLOS were 8 and 11.1 days, respectively. Significant predictors of longer PLOS included increasing age, female sex, history of chronic obstructive pulmonary disease, cerebrovascular disease, or mitral valve disease, elevated admission blood urea nitrogen, and preoperative placement of an intraaortic balloon pump. Hospitals varied significantly (P =.0001) in their unadjusted PLOS. These hospital-level variations persisted despite adjustment for both preoperative patient characteristics (P =.0001) and postoperative complications and death (P =.0001).

CONCLUSIONS:This study found significant between-hospital variations in PLOS that were not explained by patient factors. This finding suggests the potential for increased efficiency in the care of patients undergoing CABG at many institutions. Further research is needed to determine the practice patterns contributing to variations in length of stay after bypass surgery.

Holman WL, Li Q, Kiefe CI, McGiffin DC, Peterson ED, Allman RM, Nielsen VG, Pacifico AD.; Prophylactic value of preincision intra-aortic balloon pump: analysis of a statewide experience. J Thorac Cardiovasc Surg 2000 Dec;120(6):1112-9

OBJECTIVE:The objective of this study was to determine whether preincision use of an intra-aortic balloon pump improves survival and shortens postoperative length of stay in hemodynamically stable, high-risk patients undergoing coronary artery bypass grafting.

METHODS:A post hoc analysis of the Alabama CABG Cooperative Project database was performed by using propensity scores to model the likelihood of receiving a prophylactic preincision intra-aortic balloon pump. Every patient receiving a prophylactic preincision balloon pump was matched with another patient of similar propensity score who did not receive one. We then compared outcomes for matched pairs.

RESULTS:There were 7581 patients of whom 592 received a prophylactic preincision balloon pump. Patients with preoperative renal insufficiency, heart failure, or left main coronary artery disease, or who had undergone previous bypass grafting were significantly more likely to receive a prophylactic preincision balloon pump. By using propensity scores, we matched 550 patients who received a prophylactic preincision balloon pump with 550 who did not. Survival did not significantly differ by whether a prophylactic preincision balloon pump was used. However, surviving patients who received a preincision balloon pump had a significantly shorter postbypass length of stay (7 +/- 7.3 days) than did matched patients not receiving a balloon pump (8 +/- 6.2 days; P <.05).

CONCLUSIONS:No survival advantage was found for use of a prophylactic intra-aortic balloon pump in hemodynamically stable, high-risk patients undergoing bypass grafting, as opposed to placing a balloon pump on an "as needed" basis during or after the operation. However, the patients receiving the balloon pump had improved convalescence as shown by significantly shorter length of stay.

Hasdai D; Califf RM; Thompson TD; Hochman JS; Ohman EM; Pfisterer M; Bates ER; Vahanian A; Armstrong PW; Criger DA; Topol EJ; Holmes DR Jr.; Predictors of cardiogenic shock after thrombolytic therapy for acute myocardial infarction. J Am Coll Cardiol 2000 Jan;35(1):136-43

OBJECTIVE:This study characterized clinical factors predictive of cardiogenic shock developing after thrombolytic therapy for acute myocardial infarction (AMI).

BACKGROUND:Cardiogenic shock remains a common and ominous complication of AMI. By identifying patients at risk of developing shock, preventive measures may be implemented to avert its development.

METHODS:We analyzed baseline variables associated with the development of shock after thrombolytic therapy in the Global Utilization of Streptikonase and Tissue-Plasminogen Activator for Occluded Coronary Arteries (GUSTO-I) trial. Using a Cox proportional hazards model, we devised a scoring system predicting the risk of shock. This model was then validated in the Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO-III) cohort.

RESULTS:Shock developed in 1,889 patients a median of 11.6 h after enrollment. The major factors associated with increased adjusted risk of shock were age (chi2 = 285, hazard ratio [95% confidence interval] 1.47 [1.40, 1.53]), systolic blood pressure (chi2 = 280), heart rate (chi2 = 225) and Killip class (chi2 = 161, hazard ratio 1.70 [1.52, 1.90] and 2.95 [2.39, 3.63] for Killip II versus I and Killip III versus I, respectively) upon presentation. Together, these four variables accounted for >85% of the predictive information. These findings were transformed into an algorithm with a validated concordance index of 0.758. Applied to the GUSTO-III cohort, the four variables accounted for > 95% of the predictive information, and the validated concordance index was 0.796.

CONCLUSIONS:A scoring system accurately predicts the risk of shock after thrombolytic therapy for AMI based primarily on the patient's age and physical examination on presentation.

Velez CA; Kahn J; Compartment syndrome from balloon pump. Catheter Cardiovasc Interv 2000 Oct;51(2):217-9

A 35-year-old man had significant left main coronary artery disease and required intra-aortic balloon catheter insertion owing to refractory ischemia before emergency coronary artery bypass graft. In the immediate postoperative period the patient started complaining of leg pain and diminished sensation in the right foot despite palpable pulses. The diagnosis of acute compartment syndrome of the right leg was made by an intracompartment pressure measurement of 90 mm Hg.

Kang N; Edwards M; Larbalestier R; Preoperative intraaortic balloon pumps in high-risk patients undergoing open heart surgery. Ann Thorac Surg 2001 Jul;72(1):54-7

BACKGROUND:The use of the preoperative intraaortic balloon pump (IABP) in patients with severe left ventricular dysfunction or unstable angina with critical coronary anatomy is becoming more frequent as surgical casemix changes. The aim of this study was to determine the impact of preoperative IABP use on survival in high-risk patients having open heart surgery.

METHODS:Prospectively collected data for 645 consecutive patients were reviewed. Patients receiving an IABP were identified and grouped as follows: group A (preoperative IABP for high-risk nonemergent cases), group B (preoperative IABP for emergent cases), and group C (intra/postoperative IABP). Risk-adjusted hospital mortality rates in these three groups was compared using the modified Parsonnet score for preoperative risk stratification.

RESULTS:IABPs were used in 101 cases (16%). The predicted versus actual hospital mortality rate was 20% versus 5.7% in group A, 32.1% versus 47.6% in group B, and 12.6% versus 22.2% in group C (group A vs group B, p = 0.0014; group A vs group C, p = 0.012). IABP-related morbidity occurred in 3% of cases (all in group C).

CONCLUSIONS:Risk-adjusted mortality was significantly lower in high-risk cases with preoperative IABPs compared with emergent cases and intraoperative/postoperative IABPs. We encourage the use of preoperative IABPs in selected high-risk patients.

Menon V; Hochman JS; Stebbins A; Pfisterer M; Col J; Anderson RD; Hasdai D; Holmes DR; Bates ER; Topol EJ; Califf RM; Ohman EM; Lack of progress in cardiogenic shock: lessons from the GUSTO trials. Eur Heart J 2000 Dec;21(23):1928-36

OBJECTIVES:We used the GUSTO-I and GUSTO-III databases to evaluate our performance in treating cardiogenic shock patients over much of the 1990s.

METHODS &; RESULTS:GUSTO-I (1990-1993) and GUSTO-III (1995-1997) prospectively identified all patients with cardiogenic shock complicating acute myocardial infarction. Demographics, clinical presentation and outcomes for cardiogenic shock patients in the two trials were compared. Only patients enrolled with cardiogenic shock in countries common to both trials were included in these analysis. The 695 patients with cardiogenic shock in GUSTO-III were compared with the 2814 patients with cardiogenic shock in GUSTO-I. GUSTO-III patients were older (P=0.0001) and more likely to be diabetic (P=0.009) and hypertensive (P=0.025). They had a higher Killip class (P=0.002) and significantly greater index anterior infarction than cardiogenic shock patients enrolled in GUSTO-I. Time to treatment, presentation heart rate, and diastolic blood pressure were similar; however, systolic blood pressure at presentation was higher among GUSTO-III patients (P=0.002). Rates of coronary angiography, pulmonary artery catheterization, and mechanical ventilation declined in GUSTO-III compared with GUSTO-I (P=0.001); rates of angioplasty and bypass surgery were similar. Cardiogenic shock mortality in GUSTO-III was significantly higher than in GUSTO-I (62 vs 54%, P=0.001), as were rates of reinfarction (14 vs 11%, P=0.013) and recurrent ischaemia (35 vs 27%, P=0.00001). Mortality at non-U.S. sites (68 and 64%) was higher than at U.S. sites (53 and 50%) in both GUSTO-I and GUSTO-III studies, respectively. Angioplasty, bypass surgery, and balloon pump rates were lower for non-U.S. patients.

CONCLUSIONS:Cardiogenic shock continues to be associated with high mortality in thrombolytic-treated patients. Lower mortality observed in the U.S.A. supports consideration for percutaneous and surgical revascularization. Copyright 2000 The European Society of Cardiology.